Test SQ poll threads. Unstable and in fact slower :(

2020-03-03 17:23:39 +03:00
104 changed files with 2954 additions and 16220 deletions
--- a/.gitmodules
+++ b/.gitmodules
@ -1,6 +0,0 @@
 [submodule "cpp-btree"]
 	path = cpp-btree
 	url = ../cpp-btree.git
 [submodule "json11"]
 	path = json11
 	url = ../json11.git
--- a/GPL-2.0.txt
+++ b/GPL-2.0.txt
@ -1,339 +0,0 @@
                    GNU GENERAL PUBLIC LICENSE
                       Version 2, June 1991
 Copyright (C) 1989, 1991 Free Software Foundation, Inc.,
 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 Everyone is permitted to copy and distribute verbatim copies
 of this license document, but changing it is not allowed.
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--- a/Make-gen.pl
+++ b/Make-gen.pl
@ -1,46 +0,0 @@
 #!/usr/bin/perl
 use strict;
 my $deps = {};
 for my $line (split /\n/, `grep '^#include "' *.cpp *.h`)
 {
    if ($line =~ /^([^:]+):\#include "([^"]+)"/s)
    {
        $deps->{$1}->{$2} = 1;
    }
 }
 my $added;
 do
 {
    $added = 0;
    for my $file (keys %$deps)
    {
        for my $dep (keys %{$deps->{$file}})
        {
            if ($deps->{$dep})
            {
                for my $subdep (keys %{$deps->{$dep}})
                {
                    if (!$deps->{$file}->{$subdep})
                    {
                        $added = 1;
                        $deps->{$file}->{$subdep} = 1;
                    }
                }
            }
        }
    }
 } while ($added);
 for my $file (sort keys %$deps)
 {
    if ($file =~ /\.cpp$/)
    {
        my $obj = $file;
        $obj =~ s/\.cpp$/.o/s;
        print "$obj: $file ".join(" ", sort keys %{$deps->{$file}})."\n";
        print "\tg++ \$(CXXFLAGS) -c -o \$\@ \$\<\n";
    }
 }
--- a/205
+++ b/205
@ -1,169 +1,66 @@
 BLOCKSTORE_OBJS := allocator.o blockstore.o blockstore_impl.o blockstore_init.o blockstore_open.o blockstore_journal.o blockstore_read.o \
-	blockstore_write.o blockstore_sync.o blockstore_stable.o blockstore_rollback.o blockstore_flush.o crc32c.o ringloop.o
+	blockstore_write.o blockstore_sync.o blockstore_stable.o blockstore_rollback.o blockstore_flush.o crc32c.o ringloop.o timerfd_interval.o
 # -fsanitize=address
 CXXFLAGS := -g -O3 -Wall -Wno-sign-compare -Wno-comment -Wno-parentheses -Wno-pointer-arith -fPIC -fdiagnostics-color=always
-all: libfio_blockstore.so osd libfio_sec_osd.so libfio_cluster.so stub_osd stub_uring_osd stub_bench osd_test dump_journal qemu_driver.so nbd_proxy
+all: $(BLOCKSTORE_OBJS) libfio_blockstore.so osd libfio_sec_osd.so test_blockstore stub_osd stub_bench osd_test
 clean:
 	rm -f *.o
-dump_journal: dump_journal.cpp crc32c.o blockstore_journal.h
+crc32c.o: crc32c.c
 	g++ $(CXXFLAGS) -o $@ $< crc32c.o
 libblockstore.so: $(BLOCKSTORE_OBJS)
 	g++ $(CXXFLAGS) -o $@ -shared $(BLOCKSTORE_OBJS) -ltcmalloc_minimal -luring
 libfio_blockstore.so: ./libblockstore.so fio_engine.o json11.o
 	g++ $(CXXFLAGS) -shared -o $@ fio_engine.o json11.o ./libblockstore.so -ltcmalloc_minimal -luring
 OSD_OBJS := osd.o osd_secondary.o msgr_receive.o msgr_send.o osd_peering.o osd_flush.o osd_peering_pg.o \
 	osd_primary.o osd_primary_subops.o etcd_state_client.o messenger.o osd_cluster.o http_client.o osd_ops.o pg_states.o \
 	osd_rmw.o json11.o base64.o timerfd_manager.o epoll_manager.o
 osd: ./libblockstore.so osd_main.cpp osd.h osd_ops.h $(OSD_OBJS)
 	g++ $(CXXFLAGS) -o $@ osd_main.cpp $(OSD_OBJS) ./libblockstore.so -ltcmalloc_minimal -luring
 stub_osd: stub_osd.o rw_blocking.o
 	g++ $(CXXFLAGS) -o $@ stub_osd.o rw_blocking.o -ltcmalloc_minimal
 STUB_URING_OSD_OBJS := stub_uring_osd.o epoll_manager.o messenger.o msgr_send.o msgr_receive.o ringloop.o timerfd_manager.o json11.o
 stub_uring_osd: $(STUB_URING_OSD_OBJS)
 	g++ $(CXXFLAGS) -o $@ -ltcmalloc_minimal $(STUB_URING_OSD_OBJS) -luring
 stub_bench: stub_bench.cpp osd_ops.h rw_blocking.o
 	g++ $(CXXFLAGS) -o $@ stub_bench.cpp rw_blocking.o -ltcmalloc_minimal
 osd_test: osd_test.cpp osd_ops.h rw_blocking.o
 	g++ $(CXXFLAGS) -o $@ osd_test.cpp rw_blocking.o -ltcmalloc_minimal
 osd_peering_pg_test: osd_peering_pg_test.cpp osd_peering_pg.o
 	g++ $(CXXFLAGS) -o $@ $< osd_peering_pg.o -ltcmalloc_minimal
 libfio_sec_osd.so: fio_sec_osd.o rw_blocking.o
 	g++ $(CXXFLAGS) -ltcmalloc_minimal -shared -o $@ fio_sec_osd.o rw_blocking.o
 FIO_CLUSTER_OBJS := cluster_client.o epoll_manager.o etcd_state_client.o \
 	messenger.o msgr_send.o msgr_receive.o ringloop.o json11.o http_client.o osd_ops.o pg_states.o timerfd_manager.o base64.o
 libfio_cluster.so: fio_cluster.o $(FIO_CLUSTER_OBJS)
 	g++ $(CXXFLAGS) -ltcmalloc_minimal -shared -o $@ $< $(FIO_CLUSTER_OBJS) -luring
 nbd_proxy: nbd_proxy.o $(FIO_CLUSTER_OBJS)
 	g++ $(CXXFLAGS) -ltcmalloc_minimal -o $@ $< $(FIO_CLUSTER_OBJS) -luring
 qemu_driver.o: qemu_driver.c qemu_proxy.h
 	gcc -I qemu/b/qemu `pkg-config glib-2.0 --cflags` \
 		-I qemu/include $(CXXFLAGS) -c -o $@ $<
 qemu_driver.so: qemu_driver.o qemu_proxy.o $(FIO_CLUSTER_OBJS)
 	g++ $(CXXFLAGS) -ltcmalloc_minimal -shared -o $@ $< $(FIO_CLUSTER_OBJS) qemu_driver.o qemu_proxy.o -luring
 test_blockstore: ./libblockstore.so test_blockstore.cpp timerfd_interval.o
 	g++ $(CXXFLAGS) -o test_blockstore test_blockstore.cpp timerfd_interval.o ./libblockstore.so -ltcmalloc_minimal -luring
 test: test.cpp osd_peering_pg.o
 	g++ $(CXXFLAGS) -o test test.cpp osd_peering_pg.o -luring -lm
 test_allocator: test_allocator.cpp allocator.o
 	g++ $(CXXFLAGS) -o test_allocator test_allocator.cpp allocator.o
 crc32c.o: crc32c.c crc32c.h
 	g++ $(CXXFLAGS) -c -o $@ $<
 json11.o: json11/json11.cpp
 	g++ $(CXXFLAGS) -c -o json11.o json11/json11.cpp
 # Autogenerated
 allocator.o: allocator.cpp allocator.h
 	g++ $(CXXFLAGS) -c -o $@ $<
 base64.o: base64.cpp base64.h
 	g++ $(CXXFLAGS) -c -o $@ $<
 blockstore.o: blockstore.cpp allocator.h blockstore.h blockstore_flush.h blockstore_impl.h blockstore_init.h blockstore_journal.h cpp-btree/btree_map.h crc32c.h malloc_or_die.h object_id.h ringloop.h
 	g++ $(CXXFLAGS) -c -o $@ $<
 blockstore_flush.o: blockstore_flush.cpp allocator.h blockstore.h blockstore_flush.h blockstore_impl.h blockstore_init.h blockstore_journal.h cpp-btree/btree_map.h crc32c.h malloc_or_die.h object_id.h ringloop.h
 	g++ $(CXXFLAGS) -c -o $@ $<
 blockstore_impl.o: blockstore_impl.cpp allocator.h blockstore.h blockstore_flush.h blockstore_impl.h blockstore_init.h blockstore_journal.h cpp-btree/btree_map.h crc32c.h malloc_or_die.h object_id.h ringloop.h
 	g++ $(CXXFLAGS) -c -o $@ $<
 blockstore_init.o: blockstore_init.cpp allocator.h blockstore.h blockstore_flush.h blockstore_impl.h blockstore_init.h blockstore_journal.h cpp-btree/btree_map.h crc32c.h malloc_or_die.h object_id.h ringloop.h
 	g++ $(CXXFLAGS) -c -o $@ $<
 blockstore_journal.o: blockstore_journal.cpp allocator.h blockstore.h blockstore_flush.h blockstore_impl.h blockstore_init.h blockstore_journal.h cpp-btree/btree_map.h crc32c.h malloc_or_die.h object_id.h ringloop.h
 	g++ $(CXXFLAGS) -c -o $@ $<
 blockstore_open.o: blockstore_open.cpp allocator.h blockstore.h blockstore_flush.h blockstore_impl.h blockstore_init.h blockstore_journal.h cpp-btree/btree_map.h crc32c.h malloc_or_die.h object_id.h ringloop.h
 	g++ $(CXXFLAGS) -c -o $@ $<
 blockstore_read.o: blockstore_read.cpp allocator.h blockstore.h blockstore_flush.h blockstore_impl.h blockstore_init.h blockstore_journal.h cpp-btree/btree_map.h crc32c.h malloc_or_die.h object_id.h ringloop.h
 	g++ $(CXXFLAGS) -c -o $@ $<
 blockstore_rollback.o: blockstore_rollback.cpp allocator.h blockstore.h blockstore_flush.h blockstore_impl.h blockstore_init.h blockstore_journal.h cpp-btree/btree_map.h crc32c.h malloc_or_die.h object_id.h ringloop.h
 	g++ $(CXXFLAGS) -c -o $@ $<
 blockstore_stable.o: blockstore_stable.cpp allocator.h blockstore.h blockstore_flush.h blockstore_impl.h blockstore_init.h blockstore_journal.h cpp-btree/btree_map.h crc32c.h malloc_or_die.h object_id.h ringloop.h
 	g++ $(CXXFLAGS) -c -o $@ $<
 blockstore_sync.o: blockstore_sync.cpp allocator.h blockstore.h blockstore_flush.h blockstore_impl.h blockstore_init.h blockstore_journal.h cpp-btree/btree_map.h crc32c.h malloc_or_die.h object_id.h ringloop.h
 	g++ $(CXXFLAGS) -c -o $@ $<
 blockstore_write.o: blockstore_write.cpp allocator.h blockstore.h blockstore_flush.h blockstore_impl.h blockstore_init.h blockstore_journal.h cpp-btree/btree_map.h crc32c.h malloc_or_die.h object_id.h ringloop.h
 	g++ $(CXXFLAGS) -c -o $@ $<
 cluster_client.o: cluster_client.cpp cluster_client.h etcd_state_client.h http_client.h json11/json11.hpp malloc_or_die.h messenger.h object_id.h osd_id.h osd_ops.h ringloop.h timerfd_manager.h
 	g++ $(CXXFLAGS) -c -o $@ $<
 dump_journal.o: dump_journal.cpp allocator.h blockstore.h blockstore_flush.h blockstore_impl.h blockstore_init.h blockstore_journal.h cpp-btree/btree_map.h crc32c.h malloc_or_die.h object_id.h ringloop.h
 	g++ $(CXXFLAGS) -c -o $@ $<
 epoll_manager.o: epoll_manager.cpp epoll_manager.h ringloop.h timerfd_manager.h
 	g++ $(CXXFLAGS) -c -o $@ $<
 etcd_state_client.o: etcd_state_client.cpp base64.h etcd_state_client.h http_client.h json11/json11.hpp object_id.h osd_id.h osd_ops.h pg_states.h timerfd_manager.h
 	g++ $(CXXFLAGS) -c -o $@ $<
 fio_cluster.o: fio_cluster.cpp cluster_client.h epoll_manager.h etcd_state_client.h fio/fio.h fio/optgroup.h http_client.h json11/json11.hpp malloc_or_die.h messenger.h object_id.h osd_id.h osd_ops.h ringloop.h timerfd_manager.h
 	g++ $(CXXFLAGS) -c -o $@ $<
 fio_engine.o: fio_engine.cpp blockstore.h fio/fio.h fio/optgroup.h json11/json11.hpp object_id.h ringloop.h
 	g++ $(CXXFLAGS) -c -o $@ $<
 fio_sec_osd.o: fio_sec_osd.cpp fio/fio.h fio/optgroup.h object_id.h osd_id.h osd_ops.h rw_blocking.h
 	g++ $(CXXFLAGS) -c -o $@ $<
 http_client.o: http_client.cpp http_client.h json11/json11.hpp timerfd_manager.h
 	g++ $(CXXFLAGS) -c -o $@ $<
 messenger.o: messenger.cpp json11/json11.hpp malloc_or_die.h messenger.h object_id.h osd_id.h osd_ops.h ringloop.h timerfd_manager.h
 	g++ $(CXXFLAGS) -c -o $@ $<
 msgr_receive.o: msgr_receive.cpp json11/json11.hpp malloc_or_die.h messenger.h object_id.h osd_id.h osd_ops.h ringloop.h timerfd_manager.h
 	g++ $(CXXFLAGS) -c -o $@ $<
 msgr_send.o: msgr_send.cpp json11/json11.hpp malloc_or_die.h messenger.h object_id.h osd_id.h osd_ops.h ringloop.h timerfd_manager.h
 	g++ $(CXXFLAGS) -c -o $@ $<
 nbd_proxy.o: nbd_proxy.cpp cluster_client.h epoll_manager.h etcd_state_client.h http_client.h json11/json11.hpp malloc_or_die.h messenger.h object_id.h osd_id.h osd_ops.h ringloop.h timerfd_manager.h
 	g++ $(CXXFLAGS) -c -o $@ $<
 osd.o: osd.cpp blockstore.h cpp-btree/btree_map.h epoll_manager.h etcd_state_client.h http_client.h json11/json11.hpp malloc_or_die.h messenger.h object_id.h osd.h osd_id.h osd_ops.h osd_peering_pg.h pg_states.h ringloop.h timerfd_manager.h
 	g++ $(CXXFLAGS) -c -o $@ $<
 osd_cluster.o: osd_cluster.cpp base64.h blockstore.h cpp-btree/btree_map.h epoll_manager.h etcd_state_client.h http_client.h json11/json11.hpp malloc_or_die.h messenger.h object_id.h osd.h osd_id.h osd_ops.h osd_peering_pg.h pg_states.h ringloop.h timerfd_manager.h
 	g++ $(CXXFLAGS) -c -o $@ $<
 osd_flush.o: osd_flush.cpp blockstore.h cpp-btree/btree_map.h epoll_manager.h etcd_state_client.h http_client.h json11/json11.hpp malloc_or_die.h messenger.h object_id.h osd.h osd_id.h osd_ops.h osd_peering_pg.h pg_states.h ringloop.h timerfd_manager.h
 	g++ $(CXXFLAGS) -c -o $@ $<
 osd_main.o: osd_main.cpp blockstore.h cpp-btree/btree_map.h epoll_manager.h etcd_state_client.h http_client.h json11/json11.hpp malloc_or_die.h messenger.h object_id.h osd.h osd_id.h osd_ops.h osd_peering_pg.h pg_states.h ringloop.h timerfd_manager.h
 	g++ $(CXXFLAGS) -c -o $@ $<
 osd_ops.o: osd_ops.cpp object_id.h osd_id.h osd_ops.h
 	g++ $(CXXFLAGS) -c -o $@ $<
 osd_peering.o: osd_peering.cpp base64.h blockstore.h cpp-btree/btree_map.h epoll_manager.h etcd_state_client.h http_client.h json11/json11.hpp malloc_or_die.h messenger.h object_id.h osd.h osd_id.h osd_ops.h osd_peering_pg.h pg_states.h ringloop.h timerfd_manager.h
 	g++ $(CXXFLAGS) -c -o $@ $<
 osd_peering_pg.o: osd_peering_pg.cpp cpp-btree/btree_map.h object_id.h osd_id.h osd_ops.h osd_peering_pg.h pg_states.h
 	g++ $(CXXFLAGS) -c -o $@ $<
 osd_peering_pg_test.o: osd_peering_pg_test.cpp cpp-btree/btree_map.h object_id.h osd_id.h osd_ops.h osd_peering_pg.h pg_states.h
 	g++ $(CXXFLAGS) -c -o $@ $<
 osd_primary.o: osd_primary.cpp blockstore.h cpp-btree/btree_map.h epoll_manager.h etcd_state_client.h http_client.h json11/json11.hpp malloc_or_die.h messenger.h object_id.h osd.h osd_id.h osd_ops.h osd_peering_pg.h osd_primary.h osd_rmw.h pg_states.h ringloop.h timerfd_manager.h
 	g++ $(CXXFLAGS) -c -o $@ $<
 osd_primary_subops.o: osd_primary_subops.cpp blockstore.h cpp-btree/btree_map.h epoll_manager.h etcd_state_client.h http_client.h json11/json11.hpp malloc_or_die.h messenger.h object_id.h osd.h osd_id.h osd_ops.h osd_peering_pg.h osd_primary.h osd_rmw.h pg_states.h ringloop.h timerfd_manager.h
 	g++ $(CXXFLAGS) -c -o $@ $<
 osd_rmw.o: osd_rmw.cpp malloc_or_die.h object_id.h osd_id.h osd_rmw.h xor.h
 	g++ $(CXXFLAGS) -c -o $@ $<
 osd_rmw_test.o: osd_rmw_test.cpp malloc_or_die.h object_id.h osd_id.h osd_rmw.cpp osd_rmw.h test_pattern.h xor.h
 	g++ $(CXXFLAGS) -c -o $@ $<
 osd_secondary.o: osd_secondary.cpp blockstore.h cpp-btree/btree_map.h epoll_manager.h etcd_state_client.h http_client.h json11/json11.hpp malloc_or_die.h messenger.h object_id.h osd.h osd_id.h osd_ops.h osd_peering_pg.h pg_states.h ringloop.h timerfd_manager.h
 	g++ $(CXXFLAGS) -c -o $@ $<
 osd_test.o: osd_test.cpp object_id.h osd_id.h osd_ops.h rw_blocking.h test_pattern.h
 	g++ $(CXXFLAGS) -c -o $@ $<
 pg_states.o: pg_states.cpp pg_states.h
 	g++ $(CXXFLAGS) -c -o $@ $<
 qemu_proxy.o: qemu_proxy.cpp cluster_client.h etcd_state_client.h http_client.h json11/json11.hpp malloc_or_die.h messenger.h object_id.h osd_id.h osd_ops.h qemu_proxy.h ringloop.h timerfd_manager.h
 	g++ $(CXXFLAGS) -c -o $@ $<
 ringloop.o: ringloop.cpp ringloop.h
 	g++ $(CXXFLAGS) -c -o $@ $<
 timerfd_interval.o: timerfd_interval.cpp timerfd_interval.h ringloop.h
 	g++ $(CXXFLAGS) -c -o $@ $<
 %.o: %.cpp allocator.h blockstore_flush.h blockstore.h blockstore_impl.h blockstore_init.h blockstore_journal.h crc32c.h ringloop.h timerfd_interval.h object_id.h
 	g++ $(CXXFLAGS) -c -o $@ $<
 libblockstore.so: $(BLOCKSTORE_OBJS)
 	g++ $(CXXFLAGS) -o libblockstore.so -shared $(BLOCKSTORE_OBJS) -ltcmalloc_minimal -luring
 libfio_blockstore.so: ./libblockstore.so fio_engine.cpp json11.o
 	g++ $(CXXFLAGS) -shared -o libfio_blockstore.so fio_engine.cpp json11.o ./libblockstore.so -ltcmalloc_minimal -luring
 OSD_OBJS := osd.o osd_secondary.o osd_receive.o osd_send.o osd_peering.o osd_peering_pg.o osd_primary.o osd_rmw.o json11.o timerfd_interval.o
 osd_secondary.o: osd_secondary.cpp osd.h osd_ops.h ringloop.h
 	g++ $(CXXFLAGS) -c -o $@ $<
 osd_receive.o: osd_receive.cpp osd.h osd_ops.h ringloop.h
 	g++ $(CXXFLAGS) -c -o $@ $<
 osd_send.o: osd_send.cpp osd.h osd_ops.h ringloop.h
 	g++ $(CXXFLAGS) -c -o $@ $<
 osd_peering.o: osd_peering.cpp osd.h osd_ops.h osd_peering_pg.h ringloop.h
 	g++ $(CXXFLAGS) -c -o $@ $<
 osd_peering_pg.o: osd_peering_pg.cpp object_id.h osd_peering_pg.h
 	g++ $(CXXFLAGS) -c -o $@ $<
 osd_rmw.o: osd_rmw.cpp osd_rmw.h xor.h
 	g++ $(CXXFLAGS) -c -o $@ $<
 osd_rmw_test: osd_rmw_test.cpp osd_rmw.cpp osd_rmw.h xor.h
 	g++ $(CXXFLAGS) -o $@ $<
 osd_primary.o: osd_primary.cpp osd.h osd_ops.h osd_peering_pg.h xor.h ringloop.h
 	g++ $(CXXFLAGS) -c -o $@ $<
 osd.o: osd.cpp osd.h osd_ops.h osd_peering_pg.h ringloop.h
 	g++ $(CXXFLAGS) -c -o $@ $<
 osd: ./libblockstore.so osd_main.cpp osd.h osd_ops.h $(OSD_OBJS)
 	g++ $(CXXFLAGS) -o osd osd_main.cpp $(OSD_OBJS) ./libblockstore.so -ltcmalloc_minimal -luring
 stub_osd: stub_osd.cpp osd_ops.h rw_blocking.o
 	g++ $(CXXFLAGS) -o stub_osd stub_osd.cpp rw_blocking.o -ltcmalloc_minimal
 stub_bench: stub_bench.cpp osd_ops.h rw_blocking.o
 	g++ $(CXXFLAGS) -o stub_bench stub_bench.cpp rw_blocking.o -ltcmalloc_minimal
 rw_blocking.o: rw_blocking.cpp rw_blocking.h
 	g++ $(CXXFLAGS) -c -o $@ $<
-stub_bench.o: stub_bench.cpp object_id.h osd_id.h osd_ops.h rw_blocking.h
+osd_test: osd_test.cpp osd_ops.h rw_blocking.o
-	g++ $(CXXFLAGS) -c -o $@ $<
+	g++ $(CXXFLAGS) -o osd_test osd_test.cpp rw_blocking.o -ltcmalloc_minimal
-stub_osd.o: stub_osd.cpp object_id.h osd_id.h osd_ops.h rw_blocking.h
+
-	g++ $(CXXFLAGS) -c -o $@ $<
+libfio_sec_osd.so: fio_sec_osd.cpp osd_ops.h rw_blocking.o
-stub_uring_osd.o: stub_uring_osd.cpp epoll_manager.h json11/json11.hpp malloc_or_die.h messenger.h object_id.h osd_id.h osd_ops.h ringloop.h timerfd_manager.h
+	g++ $(CXXFLAGS) -ltcmalloc_minimal -shared -o libfio_sec_osd.so fio_sec_osd.cpp rw_blocking.o -luring
-	g++ $(CXXFLAGS) -c -o $@ $<
+
-test.o: test.cpp allocator.h blockstore.h blockstore_flush.h blockstore_impl.h blockstore_init.h blockstore_journal.h cpp-btree/btree_map.h crc32c.h malloc_or_die.h object_id.h osd_id.h osd_ops.h osd_peering_pg.h pg_states.h ringloop.h
+test_blockstore: ./libblockstore.so test_blockstore.cpp
-	g++ $(CXXFLAGS) -c -o $@ $<
+	g++ $(CXXFLAGS) -o test_blockstore test_blockstore.cpp ./libblockstore.so -ltcmalloc_minimal -luring
-test_allocator.o: test_allocator.cpp allocator.h
+test: test.cpp osd_peering_pg.o
-	g++ $(CXXFLAGS) -c -o $@ $<
+	g++ $(CXXFLAGS) -o test test.cpp osd_peering_pg.o -luring
-test_blockstore.o: test_blockstore.cpp blockstore.h object_id.h ringloop.h timerfd_interval.h
+test_allocator: test_allocator.cpp allocator.o
-	g++ $(CXXFLAGS) -c -o $@ $<
+	g++ $(CXXFLAGS) -o test_allocator test_allocator.cpp allocator.o
 timerfd_interval.o: timerfd_interval.cpp ringloop.h timerfd_interval.h
 	g++ $(CXXFLAGS) -c -o $@ $<
 timerfd_manager.o: timerfd_manager.cpp timerfd_manager.h
 	g++ $(CXXFLAGS) -c -o $@ $<
--- a/README.md
+++ b/README.md
@ -1,387 +0,0 @@
 ## Vitastor
 ## The Idea
 Make Software-Defined Block Storage Great Again.
 Vitastor is a small, simple and fast clustered block storage (storage for VM drives),
 architecturally similar to Ceph which means strong consistency, primary-replication, symmetric
 clustering and automatic data distribution over any number of drives of any size
 with configurable redundancy (replication or erasure codes/XOR).
 ## Features
 Vitastor is currently a pre-release, a lot of features are missing and you can still expect
 breaking changes in the future. However, the following is implemented:
 - Basic part: highly-available block storage with symmetric clustering and no SPOF
 - Performance ;-D
 - Two redundancy schemes: Replication and XOR n+1 (simplest case of EC)
 - Configuration via simple JSON data structures in etcd
 - Automatic data distribution over OSDs, with support for:
  - Mathematical optimization for better uniformity and less data movement
  - Multiple pools
  - Placement tree
  - Configurable failure domains
 - Recovery of degraded blocks
 - Rebalancing (data movement between OSDs)
 - Lazy fsync support
 - I/O statistics reporting to etcd
 - Generic user-space client library
 - QEMU driver (built out-of-tree)
 - Loadable fio engine for benchmarks (also built out-of-tree)
 - NBD proxy for kernel mounts
 ## Roadmap
 - Packaging for Debian and, probably, CentOS too
 - OSD creation tool (OSDs currently have to be created by hand)
 - Inode deletion tool (currently you can't delete anything :))
 - Other administrative tools
 - Per-inode I/O and space usage statistics
 - jerasure EC support with any number of data and parity drives in a group
 - Parallel usage of multiple network interfaces
 - Proxmox and OpenNebula plugins
 - iSCSI proxy
 - Inode metadata storage in etcd
 - Snapshots and copy-on-write image clones
 - Operation timeouts and better failure detection
 - Checksums
 - SSD+HDD optimizations, possibly including tiered storage and soft journal flushes
 - RDMA and NVDIMM support
 - Compression (possibly)
 - Read caching using system page cache (possibly)
 ## Architecture
 Similarities:
 - Just like Ceph, Vitastor has Pools, PGs, OSDs, Monitors, Failure Domains, Placement Tree.
 - Just like Ceph, Vitastor is transactional (even though there's a "lazy fsync mode" which
  doesn't implicitly flush every operation to disks).
 - OSDs also have journal and metadata and they can also be put on separate drives.
 - Just like in Ceph, client library attempts to recover from any cluster failure so
  you can basically reboot the whole cluster and only pause, but not crash, your clients
  (I consider this a bug if the client crashes in that case).
 Some basic terms for people not familiar with Ceph:
 - OSD (Object Storage Daemon) is a process that stores data and serves read/write requests.
 - PG (Placement Group) is a container for data that (normally) shares the same replicas.
 - Pool is a container for data that has the same redundancy scheme and placement rules.
 - Monitor is a separate daemon that watches cluster state and handles failures.
 - Failure Domain is a group of OSDs that you allow to fail. It's "host" by default.
 - Placement Tree groups OSDs in a hierarchy to later split them into Failure Domains.
 Architectural differences from Ceph:
 - Vitastor's primary focus is on SSDs. Proper SSD+HDD optimizations may be added in the future, though.
 - Vitastor OSD is (and will always be) single-threaded. If you want to dedicate more than 1 core
  per drive you should run multiple OSDs each on a different partition of the drive.
  Vitastor isn't CPU-hungry though (as opposed to Ceph), so 1 core is sufficient in a lot of cases.
 - Metadata and journal are always kept in memory. Metadata size depends linearly on drive capacity
  and data store block size which is 128 KB by default. With 128 KB blocks, metadata should occupy
  around 512 MB per 1 TB (which is still less than Ceph wants). Journal doesn't have to be big,
  the example test below was conducted with only 16 MB journal. A big journal is probably even
  harmful as dirty write metadata also take some memory.
 - Vitastor storage layer doesn't have internal copy-on-write or redirect-write. I know that maybe
  it's possible to create a good copy-on-write storage, but it's much harder and makes performance
  less deterministic, so CoW isn't used in Vitastor.
 - The basic layer of Vitastor is block storage with fixed-size blocks, not object storage with
  rich semantics like in Ceph (RADOS).
 - There's a "lazy fsync" mode which allows to batch writes before flushing them to the disk.
  This allows to use Vitastor with desktop SSDs, but still lowers performance due to additional
  network roundtrips, so use server SSDs with capacitor-based power loss protection
  ("Advanced Power Loss Protection") for best performance.
 - PGs are ephemeral. This means that they aren't stored on data disks and only exist in memory
  while OSDs are running.
 - Recovery process is per-object (per-block), not per-PG. Also there are no PGLOGs.
 - Monitors don't store data. Cluster configuration and state is stored in etcd in simple human-readable
  JSON structures. Monitors only watch cluster state and handle data movement.
  Thus Vitastor's Monitor isn't a critical component of the system and is more similar to Ceph's Manager.
  Vitastor's Monitor is implemented in node.js.
 - PG distribution isn't based on consistent hashes. All PG mappings are stored in etcd.
  Rebalancing PGs between OSDs is done by mathematical optimization - data distribution problem
  is reduced to a linear programming problem and solved by lp_solve. This allows for almost
  perfect (96-99% uniformity compared to Ceph's 80-90%) data distribution in most cases, ability
  to map PGs by hand without breaking rebalancing logic, reduced OSD peer-to-peer communication
  (on average, OSDs have fewer peers) and less data movement. It also probably has a drawback -
  this method may fail in very large clusters, but up to several hundreds of OSDs it's perfectly fine.
  It's also easy to add consistent hashes in the future if something proves their necessity.
 - There's no separate CRUSH layer. You select pool redundancy scheme, placement root, failure domain
  and so on directly in pool configuration.
 ## Understanding Storage Performance
 The most important thing for fast storage is latency, not parallel iops.
 The best possible latency is achieved with one thread and queue depth of 1 which basically means
 "client load as low as possible". In this case IOPS = 1/latency, and this number doesn't
 scale with number of servers, drives, server processes or threads and so on.
 Single-threaded IOPS and latency numbers only depend on *how fast a single daemon is*.
 Why is it important? It's important because some of the applications *can't* use
 queue depth greater than 1 because their task isn't parallelizable. A notable example
 is any ACID DBMS because all of them write their WALs sequentially with fsync()s.
 fsync, by the way, is another important thing often missing in benchmarks. The point is
 that drives have cache buffers and don't guarantee that your data is actually persisted
 until you call fsync() which is translated to a FLUSH CACHE command by the OS.
 Desktop SSDs are very fast without fsync - NVMes, for example, can process ~80000 write
 operations per second with queue depth of 1 without fsync - but they're really slow with
 fsync because they have to actually write data to flash chips when you call fsync. Typical
 number is around 1000-2000 iops with fsync.
 Server SSDs often have supercapacitors that act as a built-in UPS and allow the drive
 to flush its DRAM cache to the persistent flash storage when a power loss occurs.
 This makes them perform equally well with and without fsync. This feature is called
 "Advanced Power Loss Protection" by Intel; other vendors either call it similarly
 or directly as "Full Capacitor-Based Power Loss Protection".
 All software-defined storages that I currently know are slow in terms of latency.
 Notable examples are Ceph and internal SDSes used by cloud providers like Amazon, Google,
 Yandex and so on. They're all slow and can only reach ~0.3ms read and ~0.6ms 4 KB write latency
 with best-in-slot hardware.
 And that's in the SSD era when you can buy an SSD that has ~0.04ms latency for 100 $.
 I use the following 6 commands with small variations to benchmark any storage:
 - Linear write:
  `fio -ioengine=libaio -direct=1 -invalidate=1 -name=test -bs=4M -iodepth=32 -rw=write -runtime=60 -filename=/dev/sdX`
 - Linear read:
  `fio -ioengine=libaio -direct=1 -invalidate=1 -name=test -bs=4M -iodepth=32 -rw=read -runtime=60 -filename=/dev/sdX`
 - Random write latency (this hurts storages the most):
  `fio -ioengine=libaio -direct=1 -invalidate=1 -name=test -bs=4k -iodepth=1 -fsync=1 -rw=randwrite -runtime=60 -filename=/dev/sdX`
 - Random read latency:
  `fio -ioengine=libaio -direct=1 -invalidate=1 -name=test -bs=4k -iodepth=1 -rw=randread -runtime=60 -filename=/dev/sdX`
 - Parallel write iops (use numjobs if a single CPU core is insufficient to saturate the load):
  `fio -ioengine=libaio -direct=1 -invalidate=1 -name=test -bs=4k -iodepth=128 [-numjobs=4 -group_reporting] -rw=randwrite -runtime=60 -filename=/dev/sdX`
 - Parallel read iops (use numjobs if a single CPU core is insufficient to saturate the load):
  `fio -ioengine=libaio -direct=1 -invalidate=1 -name=test -bs=4k -iodepth=128 [-numjobs=4 -group_reporting] -rw=randread -runtime=60 -filename=/dev/sdX`
 ## Vitastor's Theoretical Maximum Random Access Performance
 Replicated setups:
 - Single-threaded (T1Q1) read latency: 1 network roundtrip + 1 disk read.
 - Single-threaded write+fsync latency:
  - With immediate commit: 2 network roundtrips + 1 disk write.
  - With lazy commit: 4 network roundtrips + 1 disk write + 1 disk flush.
 - Saturated parallel read iops: min(network bandwidth, sum(disk read iops)).
 - Saturated parallel write iops: min(network bandwidth, sum(disk write iops / number of replicas / write amplification)).
 EC/XOR setups:
 - Single-threaded (T1Q1) read latency: 1.5 network roundtrips + 1 disk read.
 - Single-threaded write+fsync latency:
  - With immediate commit: 3.5 network roundtrips + 1 disk read + 2 disk writes.
  - With lazy commit: 5.5 network roundtrips + 1 disk read + 2 disk writes + 2 disk fsyncs.
  - 0.5 in actually (k-1)/k which means that an additional roundtrip doesn't happen when
    the read sub-operation can be served locally.
 - Saturated parallel read iops: min(network bandwidth, sum(disk read iops)).
 - Saturated parallel write iops: min(network bandwidth, sum(disk write iops * number of data drives / (number of data + parity drives) / write amplification)).
  In fact, you should put disk write iops under the condition of ~10% reads / ~90% writes in this formula.
 Write amplification for 4 KB blocks is usually 3-5 in Vitastor:
 1. Journal block write
 2. Journal data write
 3. Metadata block write
 4. Another journal block write for EC/XOR setups
 5. Data block write
 If you manage to get an SSD which handles 512 byte blocks well (Optane?) you may
 lower 1, 3 and 4 to 512 bytes (1/8 of data size) and get WA as low as 2.375.
 Lazy fsync also reduces WA for parallel workloads because journal blocks are only
 written when they fill up or fsync is requested.
 ## Example Comparison with Ceph
 Hardware configuration: 4 nodes, each with:
 - 6x SATA SSD Intel D3-4510 3.84 TB
 - 2x Xeon Gold 6242 (16 cores @ 2.8 GHz)
 - 384 GB RAM
 - 1x 25 GbE network interface (Mellanox ConnectX-4 LX), connected to a Juniper QFX5200 switch
 CPU powersaving was disabled. Both Vitastor and Ceph were configured with 2 OSDs per 1 SSD.
 All of the results below apply to 4 KB blocks.
 Raw drive performance:
 - T1Q1 write ~27000 iops (~0.037ms latency)
 - T1Q1 read ~9800 iops (~0.101ms latency)
 - T1Q32 write ~60000 iops
 - T1Q32 read ~81700 iops
 Ceph 15.2.4 (Bluestore):
 - T1Q1 write ~1000 iops (~1ms latency)
 - T1Q1 read ~1750 iops (~0.57ms latency)
 - T8Q64 write ~100000 iops, total CPU usage by OSDs about 40 virtual cores on each node
 - T8Q64 read ~480000 iops, total CPU usage by OSDs about 40 virtual cores on each node
 T8Q64 tests were conducted over 8 400GB RBD images from all hosts (every host was running 2 instances of fio).
 This is because Ceph has performance penalties related to running multiple clients over a single RBD image.
 cephx_sign_messages was set to false during tests, RocksDB and Bluestore settings were left at defaults.
 In fact, not that bad for Ceph. These servers are an example of well-balanced Ceph nodes.
 However, CPU usage and I/O latency were through the roof, as usual.
 Vitastor:
 - T1Q1 write: 7087 iops (0.14ms latency)
 - T1Q1 read: 6838 iops (0.145ms latency)
 - T2Q64 write: 162000 iops, total CPU usage by OSDs about 3 virtual cores on each node
 - T8Q64 read: 895000 iops, total CPU usage by OSDs about 4 virtual cores on each node
 T8Q64 read test was conducted over 1 larger inode (3.2T) from all hosts (every host was running 2 instances of fio).
 Vitastor has no performance penalties related to running multiple clients over a single inode.
 If conducted from one node with all primary OSDs moved to other nodes the result was slightly lower (689000 iops),
 this is because all operations resulted in network roundtrips between the client and the primary OSD.
 When fio was colocated with OSDs (like in Ceph benchmarks above), 1/4 of the read workload actually
 used the loopback network.
 Vitastor was configured with: `--disable_data_fsync true --immediate_commit all --flusher_count 8
  --disk_alignment 4096 --journal_block_size 4096 --meta_block_size 4096
  --journal_no_same_sector_overwrites true --journal_sector_buffer_count 1024
  --journal_size 16777216`.
 ### NBD
 NBD is currently required to mount Vitastor via kernel, but it imposes additional overhead
 due to additional copying between the kernel and userspace. This mostly hurts linear
 bandwidth, not iops.
 Vitastor with single-thread NBD on the same hardware:
 - T1Q1 write: 6000 iops (0.166ms latency)
 - T1Q1 read: 5518 iops (0.18ms latency)
 - T1Q128 write: 94400 iops
 - T1Q128 read: 103000 iops
 - Linear write (4M T1Q128): 1266 MB/s (compared to 2600 MB/s via fio)
 - Linear read (4M T1Q128): 975 MB/s (compared to 1400 MB/s via fio)
 ## Building
 - Install Linux kernel 5.4 or newer for io_uring support.
 - Install liburing 0.4 or newer and its headers.
 - Install lp_solve.
 - Install etcd.
 - Install node.js 12 or newer.
 - Install gcc and g++ 9.x.
 - Clone https://yourcmc.ru/git/vitalif/vitastor/ with submodules.
 - Install QEMU 4.x or 5.x, get its source, begin to build it, stop the build and copy headers:
   - `<qemu>/include` &rarr; `<vitastor>/qemu/include`
   - Debian:
      * Use qemu packages from the main repository
      * `<qemu>/b/qemu/config-host.h` &rarr; `<vitastor>/qemu/b/qemu/config-host.h`
      * `<qemu>/b/qemu/qapi` &rarr; `<vitastor>/qemu/b/qemu/qapi`
   - CentOS 8:
      * Use qemu packages from the Advanced-Virtualization repository. To enable it, run
        `yum install centos-release-advanced-virtualization.noarch` and then `yum install qemu`
      * `<qemu>/config-host.h` &rarr; `<vitastor>/qemu/b/qemu/config-host.h`
      * `<qemu>/qapi` &rarr; `<vitastor>/qemu/b/qemu/qapi`
   - `config-host.h` and `qapi` are required because they contain generated headers
 - Install fio 3.16, get its source and symlink it into `<vitastor>/fio`. It doesn't currently
  build with fio 3.20 or newer due to the conflicts between g++ and gcc's atomics. This will
  be fixed in the future.
 - Build Vitastor with `make -j8`.
 - Copy binaries somewhere.
 ## Running
 Please note that startup procedure isn't currently simple - you specify configuration
 and calculate disk offsets almost by hand. This will be fixed in near future.
 - Get some SATA or NVMe SSDs with capacitors (server-grade drives). You can use desktop SSDs
  with lazy fsync, but prepare for inferior single-thread latency.
 - Get a fast network (at least 10 Gbit/s).
 - Disable CPU powersaving: `cpupower idle-set -D 0 && cpupower frequency-set -g performance`.
 - Install etcd with `--max-txn-ops=100000 --auto-compaction-retention=10 --auto-compaction-mode=revision` options.
 - Create global configuration in etcd: `etcdctl put /vitastor/config/global '{"immediate_commit":"all"}'`
  (if all your drives have capacitors).
 - Create pool configuration in etcd: `etcdctl put /vitastor/config/pools '{"1":{"name":"testpool","scheme":"replicated","pg_size":2,"pg_minsize":1,"pg_count":256,"failure_domain":"host"}}'`.
 - Calculate offsets for your drives with `node ./mon/simple-offsets.js /dev/sdX`.
 - Make systemd units for your OSDs. Look at `./mon/make-units.sh` for example.
  Notable configuration variables from the example:
  - `disable_data_fsync 1` - only safe with server-grade drives with capacitors.
  - `immediate_commit all` - use this if all your drives are server-grade.
  - `disable_device_lock 1` - only required if you run multiple OSDs on one block device.
  - `flusher_count 16` - flusher is a micro-thread that removes old data from the journal.
    More flushers mean more aggressive journal flushing which allows for more throughput
    but slightly hurts latency under less load. Flushing will probably be improved in the future
    because currently high queue depths sometimes lead to performance degradation.
  - `disk_alignment`, `journal_block_size`, `meta_block_size` should be set to the internal
    block size of your SSDs which is 4096 on most drives.
  - `journal_no_same_sector_overwrites true` prevents multiple overwrites of the same journal sector.
    Some SSDs (like Intel D3-4510) don't like such overwrites so they benefit from this setting.
    When this setting is set, it is also required to raise `journal_sector_buffer_count` setting,
    which is the number of dirty journal sectors that may be written to at the same time.
 - `systemctl start vitastor.target` everywhere.
 - Start any number of monitors: `cd mon; node mon-main.js --etcd_url 'http://10.115.0.10:2379,http://10.115.0.11:2379,http://10.115.0.12:2379,http://10.115.0.13:2379' --etcd_prefix '/vitastor' --etcd_start_timeout 5`.
 - At this point, one of the monitors will configure PGs and OSDs will start them.
 - You can check PG states with `etcdctl get --prefix /vitastor/pg/state`. All PGs should become 'active'.
 - Run tests with (for example): `fio -thread -ioengine=./libfio_cluster.so -name=test -bs=4M -direct=1 -iodepth=16 -rw=write -etcd=10.115.0.10:2379/v3 -pool=1 -inode=1 -size=400G`.
 - Upload VM disk image with qemu-img (for example):
  ```
  LD_PRELOAD=./qemu_driver.so qemu-img convert -f qcow2 debian10.qcow2 -p
    -O raw 'vitastor:etcd_host=10.115.0.10\:2379/v3:pool=1:inode=1:size=2147483648'
  ```
 - Run QEMU with (for example):
  ```
  LD_PRELOAD=./qemu_driver.so qemu-system-x86_64 -enable-kvm -m 1024
    -drive 'file=vitastor:etcd_host=10.115.0.10\:2379/v3:pool=1:inode=1:size=2147483648',format=raw,if=none,id=drive-virtio-disk0,cache=none
    -device virtio-blk-pci,scsi=off,bus=pci.0,addr=0x5,drive=drive-virtio-disk0,id=virtio-disk0,bootindex=1,write-cache=off,physical_block_size=4096,logical_block_size=512
    -vnc 0.0.0.0:0
  ```
 ## Known Problems
 - OSDs may currently crash with "can't get SQE, will fall out of sync with EPOLLET"
  if you try to load them with very long iodepths because io_uring queue (ring) is limited
  and OSDs don't check if it fills up.
 - Object deletion requests may currently lead to unfound objects on crashes because
  proper handling of deletions in a cluster requires a "three-phase cleanup process"
  and it's currently not implemented. In fact, even though deletion requests are
  implemented, there's no user tool to delete anything from the cluster yet :).
  Of course I'll create such tool, but its first implementation will be vulnerable to this issue.
  It's not a big deal though, because you'll be able to just repeat the deletion request
  in this case.
 ## Implementation Principles
 - I like simple and stupid solutions, so expect Vitastor to stay simple.
 - I also like reinventing the wheel to some extent, like writing my own HTTP client
  for etcd interaction instead of using prebuilt libraries, because in this case
  I'm confident about what my code does and what it doesn't do.
 - I don't care about C++ "best practices" like RAII or proper inheritance or usage of
  smart pointers or whatever and I don't intend to change my mind, so if you're here
  looking for ideal reference C++ code, this probably isn't the right place.
 - I like node.js better than any other dynamically-typed language interpreter
  because it's faster than any other interpreter in the world, has neutral C-like
  syntax and built-in event loop. That's why Monitor is implemented in node.js.
 ## Author and License
 Copyright (c) Vitaliy Filippov (vitalif [at] yourcmc.ru), 2019+
 You can also find me in the Russian Telegram Ceph chat: https://t.me/ceph_ru
 All server-side code (OSD, Monitor and so on) is licensed under the terms of
 Vitastor Network Public License 1.0 (VNPL 1.0), a copyleft license based on
 GNU GPLv3.0 with the additional "Network Interaction" clause which requires
 opensourcing all programs directly or indirectly interacting with Vitastor
 through a computer network ("Proxy Programs"). Proxy Programs may be made public
 not only under the terms of the same license, but also under the terms of any
 GPL-Compatible Free Software License, as listed by the Free Software Foundation.
 This is a stricter copyleft license than the Affero GPL.
 Basically, you can't use the software in a proprietary environment to provide
 its functionality to users without opensourcing all intermediary components
 standing between the user and Vitastor or purchasing a commercial license
 from the author 😀.
 Client libraries (cluster_client and so on) are dual-licensed under the same
 VNPL 1.0 and also GNU GPL 2.0 or later to allow for compatibility with GPLed
 software like QEMU and fio.
 You can find the full text of VNPL-1.0 in the file [VNPL-1.0.txt](VNPL-1.0.txt).
 GPL 2.0 is also included in this repository as [GPL-2.0.txt](GPL-2.0.txt).
--- a/VNPL-1.0.txt
+++ b/VNPL-1.0.txt
@ -1,645 +0,0 @@
                     VITASTOR NETWORK PUBLIC LICENSE
                       Version 1, 17 September 2020
 Copyright (C) 2020 Vitaliy Filippov <vitalif@yourcmc.ru>
 Everyone is permitted to copy and distribute verbatim copies
 of this license document, but changing it is not allowed.
                            Preamble
  The Vitastor Network Public License is a free, copyleft license for
 software and other kinds of works, specifically designed to ensure
 cooperation with the community in the case of network server software.
  The licenses for most software and other practical works are designed
 to take away your freedom to share and change the works.  By contrast,
 GNU General Public Licenses and Vitastor Network Public License are
 intended to guarantee your freedom to share and change all versions
 of a program--to make sure it remains free software for all its users.
  When we speak of free software, we are referring to freedom, not
 price.  GNU General Public Licenses and Vitastor Network Public License
 are designed to make sure that you have the freedom to distribute copies
 of free software (and charge for them if you wish), that you receive
 source code or can get it if you want it, that you can change the software
 or use pieces of it in new free programs, and that you know you can do these
 things.
  Developers that use GNU General Public Licenses and Vitastor
 Network Public License protect your rights with two steps:
 (1) assert copyright on the software, and (2) offer
 you this License which gives you legal permission to copy, distribute
 and/or modify the software.
  A secondary benefit of defending all users' freedom is that
 improvements made in alternate versions of the program, if they
 receive widespread use, become available for other developers to
 incorporate.  Many developers of free software are heartened and
 encouraged by the resulting cooperation.  However, in the case of
 software used on network servers, this result may fail to come about.
 The GNU General Public License permits making a modified version and
 letting the public access it on a server without ever releasing its
 source code to the public. Even the GNU Affero General Public License
 permits running a modified version in a closed environment where
 public users only interact with it through a closed-source proxy, again,
 without making the program and the proxy available to the public
 for free.
  The Vitastor Network Public License is designed specifically to
 ensure that, in such cases, the modified program and the proxy stays
 available to the community. It requires the operator of a network server to
 provide the source code of the original program and all other programs
 communicating with it running there to the users of that server.
 Therefore, public use of a modified version, on a server accessible
 directly or indirectly to the public, gives the public access to the source
 code of the modified version.
  The precise terms and conditions for copying, distribution and
 modification follow.
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 (such as an express permission to practice a patent or covenant not to
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 patent against the party.
  If you convey a covered work, knowingly relying on a patent license,
 and the Corresponding Source of the work is not available for anyone
 to copy, free of charge and under the terms of this License, through a
 publicly available network server or other readily accessible means,
 then you must either (1) cause the Corresponding Source to be so
 available, or (2) arrange to deprive yourself of the benefit of the
 patent license for this particular work, or (3) arrange, in a manner
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 license to downstream recipients.  "Knowingly relying" means you have
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 covered work in a country, or your recipient's use of the covered work
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  If, pursuant to or in connection with a single transaction or
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 you grant is automatically extended to all recipients of the covered
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  A patent license is "discriminatory" if it does not include within
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 or that patent license was granted, prior to 28 March 2007.
  Nothing in this License shall be construed as excluding or limiting
 any implied license or other defenses to infringement that may
 otherwise be available to you under applicable patent law.
  12. No Surrender of Others' Freedom.
  If conditions are imposed on you (whether by court order, agreement or
 otherwise) that contradict the conditions of this License, they do not
 excuse you from the conditions of this License.  If you cannot convey a
 covered work so as to satisfy simultaneously your obligations under this
 License and any other pertinent obligations, then as a consequence you may
 not convey it at all.  For example, if you agree to terms that obligate you
 to collect a royalty for further conveying from those to whom you convey
 the Program, the only way you could satisfy both those terms and this
 License would be to refrain entirely from conveying the Program.
  13. Remote Network Interaction.
  Notwithstanding any other provision of this License, if you provide
 any user an opportunity to interact with the covered work directly
 or indirectly through a computer network, an imitation of such network,
 or an additional program (hereinafter referred to as a "Proxy Program")
 that, in turn, interacts with the covered work through a computer network,
 an imitation of such network, or another Proxy Program itself,
 you must prominently offer that user an opportunity to receive the
 Corresponding Source of the covered work and all Proxy Programs from a
 network server at no charge, through some standard or customary means of
 facilitating copying of software. The Corresponding Source for the covered
 work must be made available under the conditions of this License, and
 the Corresponding Source for all Proxy Programs must be made available
 under the conditions of either this License or any GPL-Compatible
 Free Software License, as described by the Free Software Foundation
 in their "GPL-Compatible License List".
  14. Revised Versions of this License.
  Vitastor Author may publish revised and/or new versions of
 the Vitastor Network Public License from time to time.  Such new versions
 will be similar in spirit to the present version, but may differ in detail to
 address new problems or concerns.
  Each version is given a distinguishing version number.  If the
 Program specifies that a certain numbered version of the Vitastor Network
 Public License "or any later version" applies to it, you have the
 option of following the terms and conditions either of that numbered
 version or of any later version. If the Program does not specify a version
 number of the Vitastor Network Public License, you may choose any version
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  Later license versions may give you additional or different
 permissions.  However, no additional obligations are imposed on any
 author or copyright holder as a result of your choosing to follow a
 later version.
  15. Disclaimer of Warranty.
  THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY
 APPLICABLE LAW.  EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT
 HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY
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 ALL NECESSARY SERVICING, REPAIR OR CORRECTION.
  16. Limitation of Liability.
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  17. Interpretation of Sections 15 and 16.
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 reviewing courts shall apply local law that most closely approximates
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 Program, unless a warranty or assumption of liability accompanies a
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                     END OF TERMS AND CONDITIONS
            How to Apply These Terms to Your New Programs
  If you develop a new program, and you want it to be of the greatest
 possible use to the public, the best way to achieve this is to make it
 free software which everyone can redistribute and change under these terms.
  To do so, attach the following notices to the program.  It is safest
 to attach them to the start of each source file to most effectively
 state the exclusion of warranty; and each file should have at least
 the "copyright" line and a pointer to where the full notice is found.
    <one line to give the program's name and a brief idea of what it does.>
    Copyright (C) <year>  <name of author>
    This program is free software: you can redistribute it and/or modify
    it under the terms of the Vitastor Network Public License as published by
    the Vitastor Author, either version 1 of the License, or
    (at your option) any later version.
    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    Vitastor Network Public License for more details.
 Also add information on how to contact you by electronic and paper mail.
  If your software can interact with users remotely through a computer
 network, you should also make sure that it provides a way for users to
 get its source.  For example, if your program is a web application, its
 interface could display a "Source" link that leads users to an archive
 of the code.  There are many ways you could offer source, and different
 solutions will be better for different programs; see section 13 for the
 specific requirements.
--- a/allocator.cpp
+++ b/allocator.cpp
@ -1,6 +1,3 @@
 // Copyright (c) Vitaliy Filippov, 2019+
 // License: VNPL-1.0 (see README.md for details)
 #include <stdexcept>
 #include "allocator.h"
--- a/allocator.h
+++ b/allocator.h
@ -1,6 +1,3 @@
 // Copyright (c) Vitaliy Filippov, 2019+
 // License: VNPL-1.0 (see README.md for details)
 #pragma once
 #include <stdint.h>
--- a/base64.cpp
+++ b/base64.cpp
@ -1,55 +0,0 @@
 // Copyright (c) Vitaliy Filippov, 2019+
 // License: VNPL-1.0 (see README.md for details)
 #include "base64.h"
 std::string base64_encode(const std::string &in)
 {
    std::string out;
    unsigned val = 0;
    int valb = -6;
    for (unsigned char c: in)
    {
        val = (val << 8) + c;
        valb += 8;
        while (valb >= 0)
        {
            out.push_back("ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"[(val>>valb) & 0x3F]);
            valb -= 6;
        }
    }
    if (valb > -6)
        out.push_back("ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"[((val<<8)>>(valb+8)) & 0x3F]);
    while (out.size() % 4)
        out.push_back('=');
    return out;
 }
 static char T[256] = { 0 };
 std::string base64_decode(const std::string &in)
 {
    std::string out;
    if (T[0] == 0)
    {
        for (int i = 0; i < 256; i++)
            T[i] = -1;
        for (int i = 0; i < 64; i++)
            T[(unsigned char)("ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"[i])] = i;
    }
    unsigned val = 0;
    int valb = -8;
    for (unsigned char c: in)
    {
        if (T[c] == -1)
            break;
        val = (val<<6) + T[c];
        valb += 6;
        if (valb >= 0)
        {
            out.push_back(char((val >> valb) & 0xFF));
            valb -= 8;
        }
    }
    return out;
 }
--- a/base64.h
+++ b/base64.h
@ -1,8 +0,0 @@
 // Copyright (c) Vitaliy Filippov, 2019+
 // License: VNPL-1.0 (see README.md for details)
 #pragma once
 #include <string>
 std::string base64_encode(const std::string &in);
 std::string base64_decode(const std::string &in);
--- a/blockstore.cpp
+++ b/blockstore.cpp
@ -1,6 +1,3 @@
 // Copyright (c) Vitaliy Filippov, 2019+
 // License: VNPL-1.0 (see README.md for details)
 #include "blockstore_impl.h"
 blockstore_t::blockstore_t(blockstore_config_t & config, ring_loop_t *ringloop)
@ -58,11 +55,6 @@ uint64_t blockstore_t::get_block_count()
    return impl->get_block_count();
 }
 uint64_t blockstore_t::get_free_block_count()
 {
    return impl->get_free_block_count();
 }
 uint32_t blockstore_t::get_disk_alignment()
 {
    return impl->get_disk_alignment();
--- a/blockstore.h
+++ b/blockstore.h
@ -1,6 +1,3 @@
 // Copyright (c) Vitaliy Filippov, 2019+
 // License: VNPL-1.0 (see README.md for details)
 #pragma once
 #ifndef _LARGEFILE64_SOURCE
@ -18,9 +15,7 @@
 // Memory alignment for direct I/O (usually 512 bytes)
 // All other alignments must be a multiple of this one
 #ifndef MEM_ALIGNMENT
 #define MEM_ALIGNMENT 512
 #endif
 // Default block size is 128 KB, current allowed range is 4K - 128M
 #define DEFAULT_ORDER 17
@ -30,14 +25,13 @@
 #define BS_OP_MIN 1
 #define BS_OP_READ 1
 #define BS_OP_WRITE 2
-#define BS_OP_WRITE_STABLE 3
+#define BS_OP_SYNC 3
-#define BS_OP_SYNC 4
+#define BS_OP_STABLE 4
-#define BS_OP_STABLE 5
+#define BS_OP_DELETE 5
-#define BS_OP_DELETE 6
+#define BS_OP_LIST 6
-#define BS_OP_LIST 7
+#define BS_OP_ROLLBACK 7
-#define BS_OP_ROLLBACK 8
+#define BS_OP_SYNC_STAB_ALL 8
-#define BS_OP_SYNC_STAB_ALL 9
+#define BS_OP_MAX 8
 #define BS_OP_MAX 9
 #define BS_OP_PRIVATE_DATA_SIZE 256
@ -45,9 +39,9 @@
 Blockstore opcode documentation:
-## BS_OP_READ / BS_OP_WRITE / BS_OP_WRITE_STABLE
+## BS_OP_READ / BS_OP_WRITE
-Read or write object data. WRITE_STABLE writes a version that doesn't require marking as stable.
+Read or write object data.
 Input:
 - oid = requested object
@ -56,7 +50,6 @@ Input:
  - version == 0: read the last stable version,
  - version == UINT64_MAX: read the last version,
  - otherwise: read the newest version that is <= the specified version
  - reads aren't guaranteed to return data from previous unfinished writes
  For writes:
  - if version == 0, a new version is assigned automatically
  - if version != 0, it is assigned for the new write if possible, otherwise -EINVAL is returned
@ -99,7 +92,7 @@ Input:
 - buf = pre-allocated obj_ver_id array <len> units long
 Output:
- retval = 0 or negative error number (-EINVAL, -ENOENT if no such version or -EBUSY if not synced)
+- retval = 0 or negative error number (-EINVAL)
 ## BS_OP_SYNC_STAB_ALL
@ -117,8 +110,6 @@ Input:
 - oid.stripe = PG alignment
 - len = PG count or 0 to list all objects
 - offset = PG number
 - oid.inode = min inode number or 0 to list all inodes
 - version = max inode number or 0 to list all inodes
 Output:
 - retval = total obj_ver_id count
@ -184,7 +175,6 @@ public:
    // FIXME rename to object_size
    uint32_t get_block_size();
    uint64_t get_block_count();
    uint64_t get_free_block_count();
    uint32_t get_disk_alignment();
 };
--- a/blockstore_flush.cpp
+++ b/blockstore_flush.cpp
@ -1,19 +1,14 @@
 // Copyright (c) Vitaliy Filippov, 2019+
 // License: VNPL-1.0 (see README.md for details)
 #include "blockstore_impl.h"
 journal_flusher_t::journal_flusher_t(int flusher_count, blockstore_impl_t *bs)
 {
    this->bs = bs;
    this->flusher_count = flusher_count;
    dequeuing = false;
    active_flushers = 0;
-    syncing_flushers = 0;
+    sync_threshold = flusher_count == 1 ? 1 : flusher_count/2;
-    flusher_start_threshold = bs->journal_block_size / sizeof(journal_entry_stable);
+    journal_trim_interval = sync_threshold;
    journal_trim_interval = flusher_start_threshold;
    journal_trim_counter = 0;
-    journal_superblock = bs->journal.inmemory ? bs->journal.buffer : memalign_or_die(MEM_ALIGNMENT, bs->journal_block_size);
+    journal_superblock = bs->journal.inmemory ? bs->journal.buffer : memalign(MEM_ALIGNMENT, bs->journal_block_size);
    co = new journal_flusher_co[flusher_count];
    for (int i = 0; i < flusher_count; i++)
    {
@ -60,13 +55,17 @@ journal_flusher_t::~journal_flusher_t()
 bool journal_flusher_t::is_active()
 {
-    return active_flushers > 0 || dequeuing;
+    return active_flushers > 0 || start_forced && flush_queue.size() > 0 || flush_queue.size() >= sync_threshold;
 }
 void journal_flusher_t::loop()
 {
-    for (int i = 0; (active_flushers > 0 || dequeuing) && i < flusher_count; i++)
+    for (int i = 0; i < flusher_count; i++)
    {
        if (!active_flushers && (start_forced ? !flush_queue.size() : (flush_queue.size() < sync_threshold)))
        {
            return;
        }
        co[i].loop();
    }
 }
@ -84,11 +83,6 @@ void journal_flusher_t::enqueue_flush(obj_ver_id ov)
        flush_versions[ov.oid] = ov.version;
        flush_queue.push_back(ov.oid);
    }
    if (!dequeuing && flush_queue.size() >= flusher_start_threshold)
    {
        dequeuing = true;
        bs->ringloop->wakeup();
    }
 }
 void journal_flusher_t::unshift_flush(obj_ver_id ov)
@ -104,25 +98,14 @@ void journal_flusher_t::unshift_flush(obj_ver_id ov)
        flush_versions[ov.oid] = ov.version;
        flush_queue.push_front(ov.oid);
    }
    if (!dequeuing && flush_queue.size() >= flusher_start_threshold)
    {
        dequeuing = true;
        bs->ringloop->wakeup();
    }
 }
-void journal_flusher_t::request_trim()
+void journal_flusher_t::force_start()
 {
-    dequeuing = true;
+    start_forced = true;
    trim_wanted++;
    bs->ringloop->wakeup();
 }
 void journal_flusher_t::release_trim()
 {
    trim_wanted--;
 }
 #define await_sqe(label) \
    resume_##label:\
        sqe = bs->get_sqe();\
@ -133,7 +116,6 @@ void journal_flusher_t::release_trim()
        }\
        data = ((ring_data_t*)sqe->user_data);
 // FIXME: Implement batch flushing
 bool journal_flusher_co::loop()
 {
    // This is much better than implementing the whole function as an FSM
@ -173,9 +155,10 @@ bool journal_flusher_co::loop()
    else if (wait_state == 18)
        goto resume_18;
 resume_0:
-    if (!flusher->flush_queue.size() || !flusher->dequeuing)
+    if (!flusher->flush_queue.size() ||
        !flusher->start_forced && !flusher->active_flushers && flusher->flush_queue.size() < flusher->sync_threshold)
    {
-        flusher->dequeuing = false;
+        flusher->start_forced = false;
        wait_state = 0;
        return true;
    }
@ -190,7 +173,7 @@ resume_0:
        if (repeat_it != flusher->sync_to_repeat.end())
        {
 #ifdef BLOCKSTORE_DEBUG
-            printf("Postpone %lx:%lx v%lu\n", cur.oid.inode, cur.oid.stripe, cur.version);
+            printf("Postpone %lu:%lu v%lu\n", cur.oid.inode, cur.oid.stripe, cur.version);
 #endif
            // We don't flush different parts of history of the same object in parallel
            // So we check if someone is already flushing this object
@ -203,112 +186,42 @@ resume_0:
        }
        else
            flusher->sync_to_repeat[cur.oid] = 0;
        if (dirty_end->second.journal_sector >= bs->journal.dirty_start &&
            (bs->journal.dirty_start >= bs->journal.used_start ||
            dirty_end->second.journal_sector < bs->journal.used_start))
        {
            flusher->enqueue_flush(cur);
            // We can't flush journal sectors that are still written to
            // However, as we group flushes by oid, current oid may have older writes to flush!
            // And it may even block writes if we don't flush the older version
            // (if it's in the beginning of the journal)...
            // So first try to find an older version of the same object to flush.
            bool found = false;
            while (dirty_end != bs->dirty_db.begin())
            {
                dirty_end--;
                if (dirty_end->first.oid != cur.oid)
                {
                    break;
                }
                if (!(dirty_end->second.journal_sector >= bs->journal.dirty_start &&
                    (bs->journal.dirty_start >= bs->journal.used_start ||
                    dirty_end->second.journal_sector < bs->journal.used_start)))
                {
                    found = true;
                    cur.version = dirty_end->first.version;
                    break;
                }
            }
            if (!found)
            {
                // Try other objects
                flusher->sync_to_repeat.erase(cur.oid);
                int search_left = flusher->flush_queue.size() - 1;
 #ifdef BLOCKSTORE_DEBUG
-                printf("Flusher overran writers (dirty_start=%08lx) - searching for older flushes (%d left)\n", bs->journal.dirty_start, search_left);
+        printf("Flushing %lu:%lu v%lu\n", cur.oid.inode, cur.oid.stripe, cur.version);
 #endif
                while (search_left > 0)
                {
                    cur.oid = flusher->flush_queue.front();
                    cur.version = flusher->flush_versions[cur.oid];
                    flusher->flush_queue.pop_front();
                    flusher->flush_versions.erase(cur.oid);
                    dirty_end = bs->dirty_db.find(cur);
                    if (dirty_end != bs->dirty_db.end())
                    {
                        if (dirty_end->second.journal_sector >= bs->journal.dirty_start &&
                            (bs->journal.dirty_start >= bs->journal.used_start ||
                            dirty_end->second.journal_sector < bs->journal.used_start))
                        {
 #ifdef BLOCKSTORE_DEBUG
                            printf("Write %lx:%lx v%lu is too new: offset=%08lx\n", cur.oid.inode, cur.oid.stripe, cur.version, dirty_end->second.journal_sector);
 #endif
                            flusher->enqueue_flush(cur);
                        }
                        else
                        {
                            repeat_it = flusher->sync_to_repeat.find(cur.oid);
                            if (repeat_it == flusher->sync_to_repeat.end())
                            {
                                flusher->sync_to_repeat[cur.oid] = 0;
                                break;
                            }
                        }
                    }
                    search_left--;
                }
                if (search_left <= 0)
                {
 #ifdef BLOCKSTORE_DEBUG
                    printf("No older flushes, stopping\n");
 #endif
                    flusher->dequeuing = false;
                    wait_state = 0;
                    return true;
                }
            }
        }
 #ifdef BLOCKSTORE_DEBUG
        printf("Flushing %lx:%lx v%lu\n", cur.oid.inode, cur.oid.stripe, cur.version);
 #endif
        flusher->active_flushers++;
 resume_1:
        // Find it in clean_db
        clean_it = bs->clean_db.find(cur.oid);
        old_clean_loc = (clean_it != bs->clean_db.end() ? clean_it->second.location : UINT64_MAX);
        // Scan dirty versions of the object
        if (!scan_dirty(1))
        {
            wait_state += 1;
            return false;
        }
-        // Writes and deletes shouldn't happen at the same time
+        if (copy_count == 0 && clean_loc == UINT64_MAX && !has_delete && !has_empty)
        assert(!(copy_count > 0 || has_writes) || !has_delete);
        if (copy_count == 0 && !has_writes && !has_delete || has_delete && old_clean_loc == UINT64_MAX)
        {
            // Nothing to flush
-            bs->erase_dirty(dirty_start, std::next(dirty_end), clean_loc);
+            flusher->active_flushers--;
-            goto trim_journal;
+            repeat_it = flusher->sync_to_repeat.find(cur.oid);
            if (repeat_it != flusher->sync_to_repeat.end() && repeat_it->second > cur.version)
            {
                // Requeue version
                flusher->unshift_flush({ .oid = cur.oid, .version = repeat_it->second });
            }
            flusher->sync_to_repeat.erase(repeat_it);
            wait_state = 0;
            goto resume_0;
        }
        // Find it in clean_db
        clean_it = bs->clean_db.find(cur.oid);
        old_clean_loc = (clean_it != bs->clean_db.end() ? clean_it->second.location : UINT64_MAX);
        if (clean_loc == UINT64_MAX)
        {
-            if (old_clean_loc == UINT64_MAX)
+            if (copy_count > 0 && has_delete || old_clean_loc == UINT64_MAX)
            {
                // Object not allocated. This is a bug.
                char err[1024];
                snprintf(
-                    err, 1024, "BUG: Object %lx:%lx v%lu that we are trying to flush is not allocated on the data device",
+                    err, 1024, "BUG: Object %lu:%lu v%lu that we are trying to flush is not allocated on the data device",
                    cur.oid.inode, cur.oid.stripe, cur.version
                );
                throw std::runtime_error(err);
@ -374,8 +287,9 @@ resume_1:
            data->iov = (struct iovec){ it->buf, (size_t)it->len };
            data->callback = simple_callback_w;
            my_uring_prep_writev(
-                sqe, bs->data_fd, &data->iov, 1, bs->data_offset + clean_loc + it->offset
+                sqe, bs->data_fd_index, &data->iov, 1, bs->data_offset + clean_loc + it->offset
            );
            sqe->flags |= IOSQE_FIXED_FILE;
            wait_count++;
        }
        // Sync data before writing metadata
@ -407,8 +321,9 @@ resume_1:
            data->iov = (struct iovec){ meta_old.buf, bs->meta_block_size };
            data->callback = simple_callback_w;
            my_uring_prep_writev(
-                sqe, bs->meta_fd, &data->iov, 1, bs->meta_offset + meta_old.sector
+                sqe, bs->meta_fd_index, &data->iov, 1, bs->meta_offset + meta_old.sector
            );
            sqe->flags |= IOSQE_FIXED_FILE;
            wait_count++;
        }
        if (has_delete)
@ -418,7 +333,6 @@ resume_1:
        else
        {
            clean_disk_entry *new_entry = (clean_disk_entry*)(meta_new.buf + meta_new.pos*bs->clean_entry_size);
            assert(new_entry->oid.inode == 0 || new_entry->oid == cur.oid);
            new_entry->oid = cur.oid;
            new_entry->version = cur.version;
            if (!bs->inmemory_meta)
@ -430,8 +344,9 @@ resume_1:
        data->iov = (struct iovec){ meta_new.buf, bs->meta_block_size };
        data->callback = simple_callback_w;
        my_uring_prep_writev(
-            sqe, bs->meta_fd, &data->iov, 1, bs->meta_offset + meta_new.sector
+            sqe, bs->meta_fd_index, &data->iov, 1, bs->meta_offset + meta_new.sector
        );
        sqe->flags |= IOSQE_FIXED_FILE;
        wait_count++;
    resume_7:
        if (wait_count > 0)
@ -474,9 +389,8 @@ resume_1:
        }
        // Update clean_db and dirty_db, free old data locations
        update_clean_db();
    trim_journal:
        // Clear unused part of the journal every <journal_trim_interval> flushes
-        if (!((++flusher->journal_trim_counter) % flusher->journal_trim_interval) || flusher->trim_wanted > 0)
+        if (!((++flusher->journal_trim_counter) % flusher->journal_trim_interval))
        {
            flusher->journal_trim_counter = 0;
            if (bs->journal.trim())
@ -494,7 +408,8 @@ resume_1:
                ((journal_entry_start*)flusher->journal_superblock)->crc32 = je_crc32((journal_entry*)flusher->journal_superblock);
                data->iov = (struct iovec){ flusher->journal_superblock, bs->journal_block_size };
                data->callback = simple_callback_w;
-                my_uring_prep_writev(sqe, bs->journal.fd, &data->iov, 1, bs->journal.offset);
+                my_uring_prep_writev(sqe, bs->journal_fd_index, &data->iov, 1, bs->journal.offset);
                sqe->flags |= IOSQE_FIXED_FILE;
                wait_count++;
            resume_13:
                if (wait_count > 0)
@ -506,8 +421,7 @@ resume_1:
        }
        // All done
 #ifdef BLOCKSTORE_DEBUG
-        printf("Flushed %lx:%lx v%lu (%d copies, wr:%d, del:%d), %ld left\n", cur.oid.inode, cur.oid.stripe, cur.version,
+        printf("Flushed %lu:%lu v%lu\n", cur.oid.inode, cur.oid.stripe, cur.version);
            copy_count, has_writes, has_delete, flusher->flush_queue.size());
 #endif
        flusher->active_flushers--;
        repeat_it = flusher->sync_to_repeat.find(cur.oid);
@ -535,25 +449,19 @@ bool journal_flusher_co::scan_dirty(int wait_base)
    copy_count = 0;
    clean_loc = UINT64_MAX;
    has_delete = false;
-    has_writes = false;
+    has_empty = false;
    skip_copy = false;
    clean_init_bitmap = false;
    while (1)
    {
-        if (!IS_STABLE(dirty_it->second.state))
+        if (dirty_it->second.state == ST_J_STABLE && !skip_copy)
        {
            char err[1024];
            snprintf(
                err, 1024, "BUG: Unexpected dirty_entry %lx:%lx v%lu state during flush: %d",
                dirty_it->first.oid.inode, dirty_it->first.oid.stripe, dirty_it->first.version, dirty_it->second.state
            );
            throw std::runtime_error(err);
        }
        else if (IS_JOURNAL(dirty_it->second.state) && !skip_copy)
        {
            // First we submit all reads
-            has_writes = true;
+            if (dirty_it->second.len == 0)
-            if (dirty_it->second.len != 0)
+            {
                has_empty = true;
            }
            else
            {
                offset = dirty_it->second.offset;
                end_offset = dirty_it->second.offset + dirty_it->second.len;
@ -567,22 +475,23 @@ bool journal_flusher_co::scan_dirty(int wait_base)
                    {
                        submit_offset = dirty_it->second.location + offset - dirty_it->second.offset;
                        submit_len = it == v.end() || it->offset >= end_offset ? end_offset-offset : it->offset-offset;
-                        it = v.insert(it, (copy_buffer_t){ .offset = offset, .len = submit_len, .buf = memalign_or_die(MEM_ALIGNMENT, submit_len) });
+                        it = v.insert(it, (copy_buffer_t){ .offset = offset, .len = submit_len, .buf = memalign(MEM_ALIGNMENT, submit_len) });
                        copy_count++;
                        if (bs->journal.inmemory)
                        {
                            // Take it from memory
-                            memcpy(it->buf, bs->journal.buffer + submit_offset, submit_len);
+                            memcpy(v.back().buf, bs->journal.buffer + submit_offset, submit_len);
                        }
                        else
                        {
                            // Read it from disk
                            await_sqe(0);
-                            data->iov = (struct iovec){ it->buf, (size_t)submit_len };
+                            data->iov = (struct iovec){ v.back().buf, (size_t)submit_len };
                            data->callback = simple_callback_r;
                            my_uring_prep_readv(
-                                sqe, bs->journal.fd, &data->iov, 1, bs->journal.offset + submit_offset
+                                sqe, bs->journal_fd_index, &data->iov, 1, bs->journal.offset + submit_offset
                            );
                            sqe->flags |= IOSQE_FIXED_FILE;
                            wait_count++;
                        }
                    }
@ -592,22 +501,30 @@ bool journal_flusher_co::scan_dirty(int wait_base)
                }
            }
        }
-        else if (IS_BIG_WRITE(dirty_it->second.state) && !skip_copy)
+        else if (dirty_it->second.state == ST_D_STABLE && !skip_copy)
        {
            // There is an unflushed big write. Copy small writes in its position
            has_writes = true;
            clean_loc = dirty_it->second.location;
            clean_init_bitmap = true;
            clean_bitmap_offset = dirty_it->second.offset;
            clean_bitmap_len = dirty_it->second.len;
            skip_copy = true;
        }
-        else if (IS_DELETE(dirty_it->second.state) && !skip_copy)
+        else if (dirty_it->second.state == ST_DEL_STABLE && !skip_copy)
        {
            // There is an unflushed delete
            has_delete = true;
            skip_copy = true;
        }
        else if (!IS_STABLE(dirty_it->second.state))
        {
            char err[1024];
            snprintf(
                err, 1024, "BUG: Unexpected dirty_entry %lu:%lu v%lu state during flush: %d",
                dirty_it->first.oid.inode, dirty_it->first.oid.stripe, dirty_it->first.version, dirty_it->second.state
            );
            throw std::runtime_error(err);
        }
        dirty_start = dirty_it;
        if (dirty_it == bs->dirty_db.begin())
        {
@ -643,7 +560,7 @@ bool journal_flusher_co::modify_meta_read(uint64_t meta_loc, flusher_meta_write_
    if (wr.it == flusher->meta_sectors.end())
    {
        // Not in memory yet, read it
-        wr.buf = memalign_or_die(MEM_ALIGNMENT, bs->meta_block_size);
+        wr.buf = memalign(MEM_ALIGNMENT, bs->meta_block_size);
        wr.it = flusher->meta_sectors.emplace(wr.sector, (meta_sector_t){
            .offset = wr.sector,
            .len = bs->meta_block_size,
@ -656,8 +573,9 @@ bool journal_flusher_co::modify_meta_read(uint64_t meta_loc, flusher_meta_write_
        data->callback = simple_callback_r;
        wr.submitted = true;
        my_uring_prep_readv(
-            sqe, bs->meta_fd, &data->iov, 1, bs->meta_offset + wr.sector
+            sqe, bs->meta_fd_index, &data->iov, 1, bs->meta_offset + wr.sector
        );
        sqe->flags |= IOSQE_FIXED_FILE;
        wait_count++;
    }
    else
@ -673,7 +591,7 @@ void journal_flusher_co::update_clean_db()
    if (old_clean_loc != UINT64_MAX && old_clean_loc != clean_loc)
    {
 #ifdef BLOCKSTORE_DEBUG
-        printf("Free block %lu (new location is %lu)\n", old_clean_loc >> bs->block_order, clean_loc >> bs->block_order);
+        printf("Free block %lu\n", old_clean_loc >> bs->block_order);
 #endif
        bs->data_alloc->set(old_clean_loc >> bs->block_order, false);
    }
@ -720,14 +638,14 @@ bool journal_flusher_co::fsync_batch(bool fsync_meta, int wait_base)
        });
    sync_found:
        cur_sync->ready_count++;
-        flusher->syncing_flushers++;
+        if (cur_sync->ready_count >= flusher->sync_threshold || !flusher->flush_queue.size())
        if (flusher->syncing_flushers >= flusher->flusher_count || !flusher->flush_queue.size())
        {
            // Sync batch is ready. Do it.
            await_sqe(0);
            data->iov = { 0 };
            data->callback = simple_callback_w;
-            my_uring_prep_fsync(sqe, fsync_meta ? bs->meta_fd : bs->data_fd, IORING_FSYNC_DATASYNC);
+            my_uring_prep_fsync(sqe, fsync_meta ? bs->meta_fd_index : bs->data_fd_index, IORING_FSYNC_DATASYNC);
            sqe->flags |= IOSQE_FIXED_FILE;
            cur_sync->state = 1;
            wait_count++;
        resume_1:
@ -747,7 +665,6 @@ bool journal_flusher_co::fsync_batch(bool fsync_meta, int wait_base)
            wait_state = 2;
            return false;
        }
        flusher->syncing_flushers--;
        cur_sync->ready_count--;
        if (cur_sync->ready_count == 0)
        {
--- a/blockstore_flush.h
+++ b/blockstore_flush.h
@ -1,6 +1,3 @@
 // Copyright (c) Vitaliy Filippov, 2019+
 // License: VNPL-1.0 (see README.md for details)
 struct copy_buffer_t
 {
    uint64_t offset, len;
@ -48,8 +45,8 @@ class journal_flusher_co
    std::map<object_id, uint64_t>::iterator repeat_it;
    std::function<void(ring_data_t*)> simple_callback_r, simple_callback_w;
-    bool skip_copy, has_delete, has_writes;
+    bool skip_copy, has_delete, has_empty;
-    blockstore_clean_db_t::iterator clean_it;
+    spp::sparse_hash_map<object_id, clean_entry>::iterator clean_it;
    std::vector<copy_buffer_t> v;
    std::vector<copy_buffer_t>::iterator it;
    int copy_count;
@ -76,10 +73,9 @@ public:
 // Journal flusher itself
 class journal_flusher_t
 {
-    int trim_wanted = 0;
+    bool start_forced = false;
    bool dequeuing;
    int flusher_count;
-    int flusher_start_threshold;
+    int sync_threshold;
    journal_flusher_co *co;
    blockstore_impl_t *bs;
    friend class journal_flusher_co;
@ -88,7 +84,6 @@ class journal_flusher_t
    void* journal_superblock;
    int active_flushers;
    int syncing_flushers;
    std::list<flusher_sync_t> syncs;
    std::map<object_id, uint64_t> sync_to_repeat;
@ -100,8 +95,7 @@ public:
    ~journal_flusher_t();
    void loop();
    bool is_active();
-    void request_trim();
+    void force_start();
    void release_trim();
    void enqueue_flush(obj_ver_id oid);
    void unshift_flush(obj_ver_id oid);
 };
--- a/blockstore_impl.cpp
+++ b/blockstore_impl.cpp
@ -1,6 +1,3 @@
 // Copyright (c) Vitaliy Filippov, 2019+
 // License: VNPL-1.0 (see README.md for details)
 #include "blockstore_impl.h"
 blockstore_impl_t::blockstore_impl_t(blockstore_config_t & config, ring_loop_t *ringloop)
@ -8,9 +5,9 @@ blockstore_impl_t::blockstore_impl_t(blockstore_config_t & config, ring_loop_t *
    assert(sizeof(blockstore_op_private_t) <= BS_OP_PRIVATE_DATA_SIZE);
    this->ringloop = ringloop;
    ring_consumer.loop = [this]() { loop(); };
-    ringloop->register_consumer(&ring_consumer);
+    ringloop->register_consumer(ring_consumer);
    initialized = 0;
-    zero_object = (uint8_t*)memalign_or_die(MEM_ALIGNMENT, block_size);
+    zero_object = (uint8_t*)memalign(MEM_ALIGNMENT, block_size);
    data_fd = meta_fd = journal.fd = -1;
    parse_config(config);
    try
@ -39,7 +36,7 @@ blockstore_impl_t::~blockstore_impl_t()
    delete data_alloc;
    delete flusher;
    free(zero_object);
-    ringloop->unregister_consumer(&ring_consumer);
+    ringloop->unregister_consumer(ring_consumer);
    if (data_fd >= 0)
        close(data_fd);
    if (meta_fd >= 0 && meta_fd != data_fd)
@ -101,19 +98,10 @@ void blockstore_impl_t::loop()
    {
        // try to submit ops
        unsigned initial_ring_space = ringloop->space_left();
        // FIXME: rework this "sync polling"
        auto cur_sync = in_progress_syncs.begin();
        while (cur_sync != in_progress_syncs.end())
        {
-            if (continue_sync(*cur_sync) != 2)
+            continue_sync(*cur_sync++);
            {
                // List is unmodified
                cur_sync++;
            }
            else
            {
                cur_sync = in_progress_syncs.begin();
            }
        }
        auto cur = submit_queue.begin();
        int has_writes = 0;
@ -127,13 +115,19 @@ void blockstore_impl_t::loop()
            if (PRIV(op)->wait_for)
            {
                check_wait(op);
 #ifdef BLOCKSTORE_DEBUG
                if (PRIV(op)->wait_for)
                {
                    printf("still waiting for %d\n", PRIV(op)->wait_for);
                }
 #endif
                if (PRIV(op)->wait_for == WAIT_SQE)
                {
                    break;
                }
                else if (PRIV(op)->wait_for)
                {
-                    if (op->opcode == BS_OP_WRITE || op->opcode == BS_OP_WRITE_STABLE || op->opcode == BS_OP_DELETE)
+                    if (op->opcode == BS_OP_WRITE || op->opcode == BS_OP_DELETE)
                    {
                        has_writes = 2;
                    }
@ -142,12 +136,12 @@ void blockstore_impl_t::loop()
            }
            unsigned ring_space = ringloop->space_left();
            unsigned prev_sqe_pos = ringloop->save();
-            bool dequeue_op = false;
+            int dequeue_op = 0;
            if (op->opcode == BS_OP_READ)
            {
                dequeue_op = dequeue_read(op);
            }
-            else if (op->opcode == BS_OP_WRITE || op->opcode == BS_OP_WRITE_STABLE)
+            else if (op->opcode == BS_OP_WRITE || op->opcode == BS_OP_DELETE)
            {
                if (has_writes == 2)
                {
@ -157,16 +151,6 @@ void blockstore_impl_t::loop()
                dequeue_op = dequeue_write(op);
                has_writes = dequeue_op ? 1 : 2;
            }
            else if (op->opcode == BS_OP_DELETE)
            {
                if (has_writes == 2)
                {
                    // Some writes could not be submitted
                    break;
                }
                dequeue_op = dequeue_del(op);
                has_writes = dequeue_op ? 1 : 2;
            }
            else if (op->opcode == BS_OP_SYNC)
            {
                // wait for all small writes to be submitted
@ -182,33 +166,16 @@ void blockstore_impl_t::loop()
            }
            else if (op->opcode == BS_OP_STABLE)
            {
                if (has_writes == 2)
                {
                    // Don't submit additional flushes before completing previous LISTs
                    break;
                }
                dequeue_op = dequeue_stable(op);
            }
            else if (op->opcode == BS_OP_ROLLBACK)
            {
                if (has_writes == 2)
                {
                    // Don't submit additional flushes before completing previous LISTs
                    break;
                }
                dequeue_op = dequeue_rollback(op);
            }
            else if (op->opcode == BS_OP_LIST)
            {
-                // Block LIST operation by previous modifications,
+                process_list(op);
-                // so it always returns a consistent state snapshot
+                dequeue_op = true;
                if (has_writes == 2 || inflight_writes > 0)
                    has_writes = 2;
                else
                {
                    process_list(op);
                    dequeue_op = true;
                }
            }
            if (dequeue_op)
            {
@ -238,7 +205,7 @@ void blockstore_impl_t::loop()
        {
            live = true;
        }
-        queue_stall = !live && !ringloop->has_work();
+        queue_stall = !live && !ringloop->get_loop_again();
        live = false;
    }
 }
@ -278,9 +245,19 @@ void blockstore_impl_t::check_wait(blockstore_op_t *op)
        if (ringloop->space_left() < PRIV(op)->wait_detail)
        {
            // stop submission if there's still no free space
-#ifdef BLOCKSTORE_DEBUG
+            return;
-            printf("Still waiting for %lu SQE(s)\n", PRIV(op)->wait_detail);
+        }
-#endif
+        PRIV(op)->wait_for = 0;
    }
    else if (PRIV(op)->wait_for == WAIT_IN_FLIGHT)
    {
        auto dirty_it = dirty_db.find((obj_ver_id){
            .oid = op->oid,
            .version = PRIV(op)->wait_detail,
        });
        if (dirty_it != dirty_db.end() && IS_IN_FLIGHT(dirty_it->second.state))
        {
            // do not submit
            return;
        }
        PRIV(op)->wait_for = 0;
@ -290,12 +267,8 @@ void blockstore_impl_t::check_wait(blockstore_op_t *op)
        if (journal.used_start == PRIV(op)->wait_detail)
        {
            // do not submit
 #ifdef BLOCKSTORE_DEBUG
            printf("Still waiting to flush journal offset %08lx\n", PRIV(op)->wait_detail);
 #endif
            return;
        }
        flusher->release_trim();
        PRIV(op)->wait_for = 0;
    }
    else if (PRIV(op)->wait_for == WAIT_JOURNAL_BUFFER)
@ -305,9 +278,6 @@ void blockstore_impl_t::check_wait(blockstore_op_t *op)
            journal.sector_info[next].dirty)
        {
            // do not submit
 #ifdef BLOCKSTORE_DEBUG
            printf("Still waiting for a journal buffer\n");
 #endif
            return;
        }
        PRIV(op)->wait_for = 0;
@ -316,9 +286,6 @@ void blockstore_impl_t::check_wait(blockstore_op_t *op)
    {
        if (!data_alloc->get_free_count() && !flusher->is_active())
        {
 #ifdef BLOCKSTORE_DEBUG
            printf("Still waiting for free space on the data device\n");
 #endif
            return;
        }
        PRIV(op)->wait_for = 0;
@ -332,17 +299,17 @@ void blockstore_impl_t::check_wait(blockstore_op_t *op)
 void blockstore_impl_t::enqueue_op(blockstore_op_t *op, bool first)
 {
    if (op->opcode < BS_OP_MIN || op->opcode > BS_OP_MAX ||
-        ((op->opcode == BS_OP_READ || op->opcode == BS_OP_WRITE || op->opcode == BS_OP_WRITE_STABLE) && (
+        ((op->opcode == BS_OP_READ || op->opcode == BS_OP_WRITE) && (
            op->offset >= block_size ||
            op->len > block_size-op->offset ||
            (op->len % disk_alignment)
        )) ||
-        readonly && op->opcode != BS_OP_READ && op->opcode != BS_OP_LIST ||
+        readonly && op->opcode != BS_OP_READ ||
-        first && (op->opcode == BS_OP_WRITE || op->opcode == BS_OP_WRITE_STABLE))
+        first && op->opcode == BS_OP_WRITE)
    {
        // Basic verification not passed
        op->retval = -EINVAL;
-        std::function<void (blockstore_op_t*)>(op->callback)(op);
+        op->callback(op);
        return;
    }
    if (op->opcode == BS_OP_SYNC_STAB_ALL)
@ -383,21 +350,21 @@ void blockstore_impl_t::enqueue_op(blockstore_op_t *op, bool first)
            }
        };
    }
-    if ((op->opcode == BS_OP_WRITE || op->opcode == BS_OP_WRITE_STABLE || op->opcode == BS_OP_DELETE) && !enqueue_write(op))
+    if (op->opcode == BS_OP_WRITE && !enqueue_write(op))
    {
-        std::function<void (blockstore_op_t*)>(op->callback)(op);
+        op->callback(op);
        return;
    }
-    if (op->opcode == BS_OP_SYNC && immediate_commit == IMMEDIATE_ALL)
+    if (0 && op->opcode == BS_OP_SYNC && immediate_commit)
    {
        op->retval = 0;
-        std::function<void (blockstore_op_t*)>(op->callback)(op);
+        op->callback(op);
        return;
    }
    // Call constructor without allocating memory. We'll call destructor before returning op back
    new ((void*)op->private_data) blockstore_op_private_t;
    PRIV(op)->wait_for = 0;
-    PRIV(op)->op_state = 0;
+    PRIV(op)->sync_state = 0;
    PRIV(op)->pending_ops = 0;
    if (!first)
    {
@ -410,201 +377,82 @@ void blockstore_impl_t::enqueue_op(blockstore_op_t *op, bool first)
    ringloop->wakeup();
 }
 static bool replace_stable(object_id oid, uint64_t version, int search_start, int search_end, obj_ver_id* list)
 {
    while (search_start < search_end)
    {
        int pos = search_start+(search_end-search_start)/2;
        if (oid < list[pos].oid)
        {
            search_end = pos;
        }
        else if (list[pos].oid < oid)
        {
            search_start = pos+1;
        }
        else
        {
            list[pos].version = version;
            return true;
        }
    }
    return false;
 }
 void blockstore_impl_t::process_list(blockstore_op_t *op)
 {
    // Count objects
    uint32_t list_pg = op->offset;
    uint32_t pg_count = op->len;
-    uint64_t pg_stripe_size = op->oid.stripe;
+    uint64_t parity_block_size = op->oid.stripe;
-    uint64_t min_inode = op->oid.inode;
+    if (pg_count != 0 && (parity_block_size < MIN_BLOCK_SIZE || list_pg >= pg_count))
    uint64_t max_inode = op->version;
    // Check PG
    if (pg_count != 0 && (pg_stripe_size < MIN_BLOCK_SIZE || list_pg >= pg_count))
    {
        op->retval = -EINVAL;
        FINISH_OP(op);
        return;
    }
-    // Copy clean_db entries (sorted)
+    uint64_t stable_count = 0;
-    int stable_count = 0, stable_alloc = clean_db.size() / (pg_count ? pg_count : 1);
+    if (pg_count > 0)
-    obj_ver_id *stable = (obj_ver_id*)malloc(sizeof(obj_ver_id) * stable_alloc);
+    {
-    if (!stable)
+        for (auto it = clean_db.begin(); it != clean_db.end(); it++)
        {
            uint32_t pg = (it->first.inode + it->first.stripe / parity_block_size) % pg_count;
            if (pg == list_pg)
            {
                stable_count++;
            }
        }
    }
    else
    {
        stable_count = clean_db.size();
    }
    uint64_t total_count = stable_count;
    for (auto it = dirty_db.begin(); it != dirty_db.end(); it++)
    {
        if (!pg_count || ((it->first.oid.inode + it->first.oid.stripe / parity_block_size) % pg_count) == list_pg)
        {
            if (IS_STABLE(it->second.state))
            {
                stable_count++;
            }
            total_count++;
        }
    }
    // Allocate memory
    op->version = stable_count;
    op->retval = total_count;
    op->buf = malloc(sizeof(obj_ver_id) * total_count);
    if (!op->buf)
    {
        op->retval = -ENOMEM;
        FINISH_OP(op);
        return;
    }
    obj_ver_id *vers = (obj_ver_id*)op->buf;
    int i = 0;
    for (auto it = clean_db.begin(); it != clean_db.end(); it++)
    {
-        auto clean_it = clean_db.begin(), clean_end = clean_db.end();
+        if (!pg_count || ((it->first.inode + it->first.stripe / parity_block_size) % pg_count) == list_pg)
        if ((min_inode != 0 || max_inode != 0) && min_inode <= max_inode)
        {
-            clean_it = clean_db.lower_bound({
+            vers[i++] = {
-                .inode = min_inode,
+                .oid = it->first,
-                .stripe = 0,
+                .version = it->second.version,
-            });
+            };
            clean_end = clean_db.upper_bound({
                .inode = max_inode,
                .stripe = UINT64_MAX,
            });
        }
-        for (; clean_it != clean_end; clean_it++)
+    }
    int j = stable_count;
    for (auto it = dirty_db.begin(); it != dirty_db.end(); it++)
    {
        if (!pg_count || ((it->first.oid.inode + it->first.oid.stripe / parity_block_size) % pg_count) == list_pg)
        {
-            if (!pg_count || ((clean_it->first.inode + clean_it->first.stripe / pg_stripe_size) % pg_count) == list_pg)
+            if (IS_STABLE(it->second.state))
            {
-                if (stable_count >= stable_alloc)
+                vers[i++] = it->first;
-                {
+            }
-                    stable_alloc += 32768;
+            else
-                    stable = (obj_ver_id*)realloc(stable, sizeof(obj_ver_id) * stable_alloc);
+            {
-                    if (!stable)
+                vers[j++] = it->first;
                    {
                        op->retval = -ENOMEM;
                        FINISH_OP(op);
                        return;
                    }
                }
                stable[stable_count++] = {
                    .oid = clean_it->first,
                    .version = clean_it->second.version,
                };
            }
        }
    }
    int clean_stable_count = stable_count;
    // Copy dirty_db entries (sorted, too)
    int unstable_count = 0, unstable_alloc = 0;
    obj_ver_id *unstable = NULL;
    {
        auto dirty_it = dirty_db.begin(), dirty_end = dirty_db.end();
        if ((min_inode != 0 || max_inode != 0) && min_inode <= max_inode)
        {
            dirty_it = dirty_db.lower_bound({
                .oid = {
                    .inode = min_inode,
                    .stripe = 0,
                },
                .version = 0,
            });
            dirty_end = dirty_db.upper_bound({
                .oid = {
                    .inode = max_inode,
                    .stripe = UINT64_MAX,
                },
                .version = UINT64_MAX,
            });
        }
        for (; dirty_it != dirty_end; dirty_it++)
        {
            if (!pg_count || ((dirty_it->first.oid.inode + dirty_it->first.oid.stripe / pg_stripe_size) % pg_count) == list_pg)
            {
                if (IS_DELETE(dirty_it->second.state))
                {
                    // Deletions are always stable, so try to zero out two possible entries
                    if (!replace_stable(dirty_it->first.oid, 0, 0, clean_stable_count, stable))
                    {
                        replace_stable(dirty_it->first.oid, 0, clean_stable_count, stable_count, stable);
                    }
                }
                else if (IS_STABLE(dirty_it->second.state))
                {
                    // First try to replace a clean stable version in the first part of the list
                    if (!replace_stable(dirty_it->first.oid, dirty_it->first.version, 0, clean_stable_count, stable))
                    {
                        // Then try to replace the last dirty stable version in the second part of the list
                        if (stable[stable_count-1].oid == dirty_it->first.oid)
                        {
                            stable[stable_count-1].version = dirty_it->first.version;
                        }
                        else
                        {
                            if (stable_count >= stable_alloc)
                            {
                                stable_alloc += 32768;
                                stable = (obj_ver_id*)realloc(stable, sizeof(obj_ver_id) * stable_alloc);
                                if (!stable)
                                {
                                    if (unstable)
                                        free(unstable);
                                    op->retval = -ENOMEM;
                                    FINISH_OP(op);
                                    return;
                                }
                            }
                            stable[stable_count++] = dirty_it->first;
                        }
                    }
                }
                else
                {
                    if (unstable_count >= unstable_alloc)
                    {
                        unstable_alloc += 32768;
                        unstable = (obj_ver_id*)realloc(unstable, sizeof(obj_ver_id) * unstable_alloc);
                        if (!unstable)
                        {
                            if (stable)
                                free(stable);
                            op->retval = -ENOMEM;
                            FINISH_OP(op);
                            return;
                        }
                    }
                    unstable[unstable_count++] = dirty_it->first;
                }
            }
        }
    }
    // Remove zeroed out stable entries
    int j = 0;
    for (int i = 0; i < stable_count; i++)
    {
        if (stable[i].version != 0)
        {
            stable[j++] = stable[i];
        }
    }
    stable_count = j;
    if (stable_count+unstable_count > stable_alloc)
    {
        stable_alloc = stable_count+unstable_count;
        stable = (obj_ver_id*)realloc(stable, sizeof(obj_ver_id) * stable_alloc);
        if (!stable)
        {
            if (unstable)
                free(unstable);
            op->retval = -ENOMEM;
            FINISH_OP(op);
            return;
        }
    }
    // Copy unstable entries
    for (int i = 0; i < unstable_count; i++)
    {
        stable[j++] = unstable[i];
    }
    free(unstable);
    op->version = stable_count;
    op->retval = stable_count+unstable_count;
    op->buf = stable;
    FINISH_OP(op);
 }
--- a/blockstore_impl.h
+++ b/blockstore_impl.h
@ -1,15 +1,14 @@
 // Copyright (c) Vitaliy Filippov, 2019+
 // License: VNPL-1.0 (see README.md for details)
 #pragma once
 #include "blockstore.h"
 #include "timerfd_interval.h"
 #include <sys/types.h>
 #include <sys/ioctl.h>
 #include <sys/stat.h>
 #include <fcntl.h>
 #include <unistd.h>
 #include <malloc.h>
 #include <linux/fs.h>
 #include <vector>
@ -17,40 +16,43 @@
 #include <deque>
 #include <new>
-#include "cpp-btree/btree_map.h"
+#include "sparsepp/sparsepp/spp.h"
 #include "malloc_or_die.h"
 #include "allocator.h"
 //#define BLOCKSTORE_DEBUG
 // States are not stored on disk. Instead, they're deduced from the journal
 // FIXME: Rename to BS_ST_*
-#define BS_ST_SMALL_WRITE 0x01
+#define ST_J_IN_FLIGHT 1
-#define BS_ST_BIG_WRITE 0x02
+#define ST_J_SUBMITTED 2
-#define BS_ST_DELETE 0x03
+#define ST_J_WRITTEN 3
 #define ST_J_SYNCED 4
 #define ST_J_STABLE 5
-#define BS_ST_WAIT_BIG 0x10
+#define ST_D_IN_FLIGHT 15
-#define BS_ST_IN_FLIGHT 0x20
+#define ST_D_SUBMITTED 16
-#define BS_ST_SUBMITTED 0x30
+#define ST_D_WRITTEN 17
-#define BS_ST_WRITTEN 0x40
+#define ST_D_META_WRITTEN 19
-#define BS_ST_SYNCED 0x50
+#define ST_D_META_SYNCED 20
-#define BS_ST_STABLE 0x60
+#define ST_D_STABLE 21
-#define BS_ST_INSTANT 0x100
+#define ST_DEL_IN_FLIGHT 31
 #define ST_DEL_SUBMITTED 32
 #define ST_DEL_WRITTEN 33
 #define ST_DEL_SYNCED 34
 #define ST_DEL_STABLE 35
-#define IMMEDIATE_NONE 0
+#define ST_CURRENT 48
 #define IMMEDIATE_SMALL 1
 #define IMMEDIATE_ALL 2
-#define BS_ST_TYPE_MASK 0x0F
+#define IS_IN_FLIGHT(st) (st == ST_J_IN_FLIGHT || st == ST_D_IN_FLIGHT || st == ST_DEL_IN_FLIGHT || st == ST_J_SUBMITTED || st == ST_D_SUBMITTED || st == ST_DEL_SUBMITTED)
-#define BS_ST_WORKFLOW_MASK 0xF0
+#define IS_STABLE(st) (st == ST_J_STABLE || st == ST_D_STABLE || st == ST_DEL_STABLE || st == ST_CURRENT)
-#define IS_IN_FLIGHT(st) (((st) & 0xF0) <= BS_ST_SUBMITTED)
+#define IS_SYNCED(st) (IS_STABLE(st) || st == ST_J_SYNCED || st == ST_D_META_SYNCED || st == ST_DEL_SYNCED)
-#define IS_STABLE(st) (((st) & 0xF0) == BS_ST_STABLE)
+#define IS_JOURNAL(st) (st >= ST_J_SUBMITTED && st <= ST_J_STABLE)
-#define IS_SYNCED(st) (((st) & 0xF0) >= BS_ST_SYNCED)
+#define IS_BIG_WRITE(st) (st >= ST_D_SUBMITTED && st <= ST_D_STABLE)
-#define IS_JOURNAL(st) (((st) & 0x0F) == BS_ST_SMALL_WRITE)
+#define IS_DELETE(st) (st >= ST_DEL_SUBMITTED && st <= ST_DEL_STABLE)
-#define IS_BIG_WRITE(st) (((st) & 0x0F) == BS_ST_BIG_WRITE)
+#define IS_UNSYNCED(st) (st >= ST_J_SUBMITTED && st <= ST_J_WRITTEN || st >= ST_D_SUBMITTED && st <= ST_D_META_WRITTEN || st >= ST_DEL_SUBMITTED && st <= ST_DEL_WRITTEN)
 #define IS_DELETE(st) (((st) & 0x0F) == BS_ST_DELETE)
 #define BS_SUBMIT_GET_SQE(sqe, data) \
    BS_SUBMIT_GET_ONLY_SQE(sqe); \
@ -122,6 +124,8 @@ struct __attribute__((__packed__)) dirty_entry
 // Suspend operation until there are more free SQEs
 #define WAIT_SQE 1
 // Suspend operation until version <wait_detail> of object <oid> is written
 #define WAIT_IN_FLIGHT 2
 // Suspend operation until there are <wait_detail> bytes of free space in the journal on disk
 #define WAIT_JOURNAL 3
 // Suspend operation until the next journal sector buffer is free
@ -135,7 +139,7 @@ struct fulfill_read_t
 };
 #define PRIV(op) ((blockstore_op_private_t*)(op)->private_data)
-#define FINISH_OP(op) PRIV(op)->~blockstore_op_private_t(); std::function<void (blockstore_op_t*)>(op->callback)(op)
+#define FINISH_OP(op) PRIV(op)->~blockstore_op_private_t(); op->callback(op)
 struct blockstore_op_private_t
 {
@ -143,13 +147,12 @@ struct blockstore_op_private_t
    int wait_for;
    uint64_t wait_detail;
    int pending_ops;
    int op_state;
    // Read
    std::vector<fulfill_read_t> read_vec;
    // Sync, write
-    uint64_t min_flushed_journal_sector, max_flushed_journal_sector;
+    uint64_t min_used_journal_sector, max_used_journal_sector;
    // Write
    struct iovec iov_zerofill[3];
@ -158,13 +161,9 @@ struct blockstore_op_private_t
    std::vector<obj_ver_id> sync_big_writes, sync_small_writes;
    int sync_small_checked, sync_big_checked;
    std::list<blockstore_op_t*>::iterator in_progress_ptr;
-    int prev_sync_count;
+    int sync_state, prev_sync_count;
 };
 // https://github.com/algorithm-ninja/cpp-btree
 // https://github.com/greg7mdp/sparsepp/ was used previously, but it was TERRIBLY slow after resizing
 // with sparsepp, random reads dropped to ~700 iops very fast with just as much as ~32k objects in the DB
 typedef btree::btree_map<object_id, clean_entry> blockstore_clean_db_t;
 typedef std::map<obj_ver_id, dirty_entry> blockstore_dirty_db_t;
 #include "blockstore_init.h"
@ -178,30 +177,29 @@ class blockstore_impl_t
    uint32_t block_size;
    uint64_t meta_offset;
    uint64_t data_offset;
-    uint64_t cfg_journal_size, cfg_data_size;
+    uint64_t cfg_journal_size;
    // Required write alignment and journal/metadata/data areas' location alignment
-    uint32_t disk_alignment = 4096;
+    uint32_t disk_alignment = 512;
    // Journal block size - minimum_io_size of the journal device is the best choice
-    uint64_t journal_block_size = 4096;
+    uint64_t journal_block_size = 512;
    // Metadata block size - minimum_io_size of the metadata device is the best choice
-    uint64_t meta_block_size = 4096;
+    uint64_t meta_block_size = 512;
    // Sparse write tracking granularity. 4 KB is a good choice. Must be a multiple of disk_alignment
    uint64_t bitmap_granularity = 4096;
    bool readonly = false;
    // By default, Blockstore locks all opened devices exclusively. This option can be used to disable locking
    bool disable_flock = false;
    // It is safe to disable fsync() if drive write cache is writethrough
    bool disable_data_fsync = false, disable_meta_fsync = false, disable_journal_fsync = false;
    // Enable if you want every operation to be executed with an "implicit fsync"
-    // Suitable only for server SSDs with capacitors, requires disabled data and journal fsyncs
+    // FIXME Not implemented yet
-    int immediate_commit = IMMEDIATE_NONE;
+    bool immediate_commit = false;
    bool inmemory_meta = false;
    int flusher_count;
    /******* END OF OPTIONS *******/
    struct ring_consumer_t ring_consumer;
-    blockstore_clean_db_t clean_db;
+    // Another option is https://github.com/algorithm-ninja/cpp-btree
    spp::sparse_hash_map<object_id, clean_entry> clean_db;
    uint8_t *clean_bitmap = NULL;
    blockstore_dirty_db_t dirty_db;
    std::list<blockstore_op_t*> submit_queue; // FIXME: funny thing is that vector is better here
@ -218,6 +216,7 @@ class blockstore_impl_t
    int data_fd;
    uint64_t meta_size, meta_area, meta_len;
    uint64_t data_size, data_len;
    int meta_fd_index, data_fd_index, journal_fd_index;
    void *metadata_buffer = NULL;
@ -226,7 +225,6 @@ class blockstore_impl_t
    bool live = false, queue_stall = false;
    ring_loop_t *ringloop;
    int inflight_writes = 0;
    bool stop_sync_submitted;
@ -267,7 +265,7 @@ class blockstore_impl_t
    bool enqueue_write(blockstore_op_t *op);
    int dequeue_write(blockstore_op_t *op);
    int dequeue_del(blockstore_op_t *op);
-    int continue_write(blockstore_op_t *op);
+    void ack_write(blockstore_op_t *op);
    void release_journal_sectors(blockstore_op_t *op);
    void handle_write_event(ring_data_t *data, blockstore_op_t *op);
@ -280,15 +278,11 @@ class blockstore_impl_t
    // Stabilize
    int dequeue_stable(blockstore_op_t *op);
    int continue_stable(blockstore_op_t *op);
    void mark_stable(const obj_ver_id & ov);
    void handle_stable_event(ring_data_t *data, blockstore_op_t *op);
    void stabilize_object(object_id oid, uint64_t max_ver);
    // Rollback
    int dequeue_rollback(blockstore_op_t *op);
    int continue_rollback(blockstore_op_t *op);
    void mark_rolled_back(const obj_ver_id & ov);
    void handle_rollback_event(ring_data_t *data, blockstore_op_t *op);
    void erase_dirty(blockstore_dirty_db_t::iterator dirty_start, blockstore_dirty_db_t::iterator dirty_end, uint64_t clean_loc);
@ -323,6 +317,5 @@ public:
    inline uint32_t get_block_size() { return block_size; }
    inline uint64_t get_block_count() { return block_count; }
    inline uint64_t get_free_block_count() { return data_alloc->get_free_count(); }
    inline uint32_t get_disk_alignment() { return disk_alignment; }
 };
--- a/blockstore_init.cpp
+++ b/blockstore_init.cpp
@ -1,6 +1,3 @@
 // Copyright (c) Vitaliy Filippov, 2019+
 // License: VNPL-1.0 (see README.md for details)
 #include "blockstore_impl.h"
 blockstore_init_meta::blockstore_init_meta(blockstore_impl_t *bs)
@ -58,7 +55,8 @@ int blockstore_init_meta::loop()
                bs->meta_len - metadata_read > bs->metadata_buf_size ? bs->metadata_buf_size : bs->meta_len - metadata_read,
            };
            data->callback = [this](ring_data_t *data) { handle_event(data); };
-            my_uring_prep_readv(sqe, bs->meta_fd, &data->iov, 1, bs->meta_offset + metadata_read);
+            my_uring_prep_readv(sqe, bs->meta_fd_index, &data->iov, 1, bs->meta_offset + metadata_read);
            sqe->flags |= IOSQE_FIXED_FILE;
            bs->ringloop->submit();
            submitted = (prev == 1 ? 2 : 1);
            prev = submitted;
@ -111,13 +109,13 @@ void blockstore_init_meta::handle_entries(void* entries, unsigned count, int blo
                {
                    // free the previous block
 #ifdef BLOCKSTORE_DEBUG
-                    printf("Free block %lu (new location is %lu)\n", clean_it->second.location >> block_order, done_cnt+i >> block_order);
+                    printf("Free block %lu\n", clean_it->second.location >> bs->block_order);
 #endif
                    bs->data_alloc->set(clean_it->second.location >> block_order, false);
                }
                entries_loaded++;
 #ifdef BLOCKSTORE_DEBUG
-                printf("Allocate block (clean entry) %lu: %lx:%lx v%lu\n", done_cnt+i, entry->oid.inode, entry->oid.stripe, entry->version);
+                printf("Allocate block (clean entry) %lu: %lu:%lu v%lu\n", done_cnt+i, entry->oid.inode, entry->oid.stripe, entry->version);
 #endif
                bs->data_alloc->set(done_cnt+i, true);
                bs->clean_db[entry->oid] = (struct clean_entry){
@ -128,7 +126,7 @@ void blockstore_init_meta::handle_entries(void* entries, unsigned count, int blo
            else
            {
 #ifdef BLOCKSTORE_DEBUG
-                printf("Old clean entry %lu: %lx:%lx v%lu\n", done_cnt+i, entry->oid.inode, entry->oid.stripe, entry->version);
+                printf("Old clean entry %lu: %lu:%lu v%lu\n", done_cnt+i, entry->oid.inode, entry->oid.stripe, entry->version);
 #endif
            }
        }
@ -205,7 +203,11 @@ int blockstore_init_journal::loop()
        goto resume_7;
    printf("Reading blockstore journal\n");
    if (!bs->journal.inmemory)
-        submitted_buf = memalign_or_die(MEM_ALIGNMENT, 2*bs->journal.block_size);
+    {
        submitted_buf = memalign(MEM_ALIGNMENT, 2*bs->journal.block_size);
        if (!submitted_buf)
            throw std::bad_alloc();
    }
    else
        submitted_buf = bs->journal.buffer;
    // Read first block of the journal
@ -215,7 +217,8 @@ int blockstore_init_journal::loop()
    data = ((ring_data_t*)sqe->user_data);
    data->iov = { submitted_buf, bs->journal.block_size };
    data->callback = simple_callback;
-    my_uring_prep_readv(sqe, bs->journal.fd, &data->iov, 1, bs->journal.offset);
+    my_uring_prep_readv(sqe, bs->journal_fd_index, &data->iov, 1, bs->journal.offset);
    sqe->flags |= IOSQE_FIXED_FILE;
    bs->ringloop->submit();
    wait_count = 1;
 resume_1:
@ -253,7 +256,8 @@ resume_1:
            GET_SQE();
            data->iov = (struct iovec){ submitted_buf, 2*bs->journal.block_size };
            data->callback = simple_callback;
-            my_uring_prep_writev(sqe, bs->journal.fd, &data->iov, 1, bs->journal.offset);
+            my_uring_prep_writev(sqe, bs->journal_fd_index, &data->iov, 1, bs->journal.offset);
            sqe->flags |= IOSQE_FIXED_FILE;
            wait_count++;
            bs->ringloop->submit();
        resume_6:
@ -265,7 +269,8 @@ resume_1:
            if (!bs->disable_journal_fsync)
            {
                GET_SQE();
-                my_uring_prep_fsync(sqe, bs->journal.fd, IORING_FSYNC_DATASYNC);
+                my_uring_prep_fsync(sqe, bs->journal_fd_index, IORING_FSYNC_DATASYNC);
                sqe->flags |= IOSQE_FIXED_FILE;
                data->iov = { 0 };
                data->callback = simple_callback;
                wait_count++;
@ -316,7 +321,7 @@ resume_1:
                if (journal_pos < bs->journal.used_start)
                    end = bs->journal.used_start;
                if (!bs->journal.inmemory)
-                    submitted_buf = memalign_or_die(MEM_ALIGNMENT, JOURNAL_BUFFER_SIZE);
+                    submitted_buf = memalign(MEM_ALIGNMENT, JOURNAL_BUFFER_SIZE);
                else
                    submitted_buf = bs->journal.buffer + journal_pos;
                data->iov = {
@ -324,7 +329,8 @@ resume_1:
                    end - journal_pos < JOURNAL_BUFFER_SIZE ? end - journal_pos : JOURNAL_BUFFER_SIZE,
                };
                data->callback = [this](ring_data_t *data1) { handle_event(data1); };
-                my_uring_prep_readv(sqe, bs->journal.fd, &data->iov, 1, bs->journal.offset + journal_pos);
+                my_uring_prep_readv(sqe, bs->journal_fd_index, &data->iov, 1, bs->journal.offset + journal_pos);
                sqe->flags |= IOSQE_FIXED_FILE;
                bs->ringloop->submit();
            }
            while (done.size() > 0)
@ -339,7 +345,8 @@ resume_1:
                        GET_SQE();
                        data->iov = { init_write_buf, bs->journal.block_size };
                        data->callback = simple_callback;
-                        my_uring_prep_writev(sqe, bs->journal.fd, &data->iov, 1, bs->journal.offset + init_write_sector);
+                        my_uring_prep_writev(sqe, bs->journal_fd_index, &data->iov, 1, bs->journal.offset + init_write_sector);
                        sqe->flags |= IOSQE_FIXED_FILE;
                        wait_count++;
                        bs->ringloop->submit();
                    resume_7:
@ -353,7 +360,8 @@ resume_1:
                            GET_SQE();
                            data->iov = { 0 };
                            data->callback = simple_callback;
-                            my_uring_prep_fsync(sqe, bs->journal.fd, IORING_FSYNC_DATASYNC);
+                            my_uring_prep_fsync(sqe, bs->journal_fd_index, IORING_FSYNC_DATASYNC);
                            sqe->flags |= IOSQE_FIXED_FILE;
                            wait_count++;
                            bs->ringloop->submit();
                        }
@ -401,9 +409,8 @@ resume_1:
    }
    // Trim journal on start so we don't stall when all entries are older
    bs->journal.trim();
    bs->journal.dirty_start = bs->journal.next_free;
    printf(
-        "Journal entries loaded: %lu, free journal space: %lu bytes (%08lx..%08lx is used), free blocks: %lu / %lu\n",
+        "Journal entries loaded: %lu, free journal space: %lu bytes (%lu..%lu is used), free blocks: %lu / %lu\n",
        entries_loaded,
        (bs->journal.next_free >= bs->journal.used_start
            ? bs->journal.len-bs->journal.block_size - (bs->journal.next_free-bs->journal.used_start)
@ -439,7 +446,7 @@ int blockstore_init_journal::handle_journal_part(void *buf, uint64_t done_pos, u
        {
            journal_entry *je = (journal_entry*)(buf + proc_pos - done_pos + pos);
            if (je->magic != JOURNAL_MAGIC || je_crc32(je) != je->crc32 ||
-                je->type < JE_MIN || je->type > JE_MAX || started && je->crc32_prev != crc32_last)
+                je->type < JE_SMALL_WRITE || je->type > JE_DELETE || started && je->crc32_prev != crc32_last)
            {
                if (pos == 0)
                {
@ -453,15 +460,10 @@ int blockstore_init_journal::handle_journal_part(void *buf, uint64_t done_pos, u
                    break;
                }
            }
-            if (je->type == JE_SMALL_WRITE || je->type == JE_SMALL_WRITE_INSTANT)
+            if (je->type == JE_SMALL_WRITE)
            {
 #ifdef BLOCKSTORE_DEBUG
-                printf(
+                printf("je_small_write oid=%lu:%lu ver=%lu offset=%u len=%u\n", je->small_write.oid.inode, je->small_write.oid.stripe, je->small_write.version, je->small_write.offset, je->small_write.len);
                    "je_small_write%s oid=%lx:%lx ver=%lu offset=%u len=%u\n",
                    je->type == JE_SMALL_WRITE_INSTANT ? "_instant" : "",
                    je->small_write.oid.inode, je->small_write.oid.stripe, je->small_write.version,
                    je->small_write.offset, je->small_write.len
                );
 #endif
                // oid, version, offset, len
                uint64_t prev_free = next_free;
@ -479,7 +481,7 @@ int blockstore_init_journal::handle_journal_part(void *buf, uint64_t done_pos, u
                if (location != je->small_write.data_offset)
                {
                    char err[1024];
-                    snprintf(err, 1024, "BUG: calculated journal data offset (%08lx) != stored journal data offset (%08lx)", location, je->small_write.data_offset);
+                    snprintf(err, 1024, "BUG: calculated journal data offset (%lu) != stored journal data offset (%lu)", location, je->small_write.data_offset);
                    throw std::runtime_error(err);
                }
                uint32_t data_crc32 = 0;
@ -514,9 +516,7 @@ int blockstore_init_journal::handle_journal_part(void *buf, uint64_t done_pos, u
                if (data_crc32 != je->small_write.crc32_data)
                {
                    // journal entry is corrupt, stop here
-                    // interesting thing is that we must clear the corrupt entry if we're not readonly,
+                    // interesting thing is that we must clear the corrupt entry if we're not readonly
                    // because we don't write next entries in the same journal block
                    printf("Journal entry data is corrupt (data crc32 %x != %x)\n", data_crc32, je->small_write.crc32_data);
                    memset(buf + proc_pos - done_pos + pos, 0, bs->journal.block_size - pos);
                    bs->journal.next_free = prev_free;
                    init_write_buf = buf + proc_pos - done_pos;
@ -525,14 +525,14 @@ int blockstore_init_journal::handle_journal_part(void *buf, uint64_t done_pos, u
                }
                auto clean_it = bs->clean_db.find(je->small_write.oid);
                if (clean_it == bs->clean_db.end() ||
-                    clean_it->second.version < je->small_write.version)
+                    clean_it->second.version < je->big_write.version)
                {
                    obj_ver_id ov = {
                        .oid = je->small_write.oid,
                        .version = je->small_write.version,
                    };
                    bs->dirty_db.emplace(ov, (dirty_entry){
-                        .state = (BS_ST_SMALL_WRITE | BS_ST_SYNCED),
+                        .state = ST_J_SYNCED,
                        .flags = 0,
                        .location = location,
                        .offset = je->small_write.offset,
@ -541,27 +541,16 @@ int blockstore_init_journal::handle_journal_part(void *buf, uint64_t done_pos, u
                    });
                    bs->journal.used_sectors[proc_pos]++;
 #ifdef BLOCKSTORE_DEBUG
-                    printf(
+                    printf("journal offset %lu is used by %lu:%lu v%lu\n", proc_pos, ov.oid.inode, ov.oid.stripe, ov.version);
                        "journal offset %08lx is used by %lx:%lx v%lu (%lu refs)\n",
                        proc_pos, ov.oid.inode, ov.oid.stripe, ov.version, bs->journal.used_sectors[proc_pos]
                    );
 #endif
                    auto & unstab = bs->unstable_writes[ov.oid];
                    unstab = unstab < ov.version ? ov.version : unstab;
                    if (je->type == JE_SMALL_WRITE_INSTANT)
                    {
                        bs->mark_stable(ov);
                    }
                }
            }
-            else if (je->type == JE_BIG_WRITE || je->type == JE_BIG_WRITE_INSTANT)
+            else if (je->type == JE_BIG_WRITE)
            {
 #ifdef BLOCKSTORE_DEBUG
-                printf(
+                printf("je_big_write oid=%lu:%lu ver=%lu loc=%lu\n", je->big_write.oid.inode, je->big_write.oid.stripe, je->big_write.version, je->big_write.location);
                    "je_big_write%s oid=%lx:%lx ver=%lu loc=%lu\n",
                    je->type == JE_BIG_WRITE_INSTANT ? "_instant" : "",
                    je->big_write.oid.inode, je->big_write.oid.stripe, je->big_write.version, je->big_write.location
                );
 #endif
                auto clean_it = bs->clean_db.find(je->big_write.oid);
                if (clean_it == bs->clean_db.end() ||
@ -573,7 +562,7 @@ int blockstore_init_journal::handle_journal_part(void *buf, uint64_t done_pos, u
                        .version = je->big_write.version,
                    };
                    bs->dirty_db.emplace(ov, (dirty_entry){
-                        .state = (BS_ST_BIG_WRITE | BS_ST_SYNCED),
+                        .state = ST_D_META_SYNCED,
                        .flags = 0,
                        .location = je->big_write.location,
                        .offset = je->big_write.offset,
@ -587,63 +576,116 @@ int blockstore_init_journal::handle_journal_part(void *buf, uint64_t done_pos, u
                    bs->journal.used_sectors[proc_pos]++;
                    auto & unstab = bs->unstable_writes[ov.oid];
                    unstab = unstab < ov.version ? ov.version : unstab;
                    if (je->type == JE_BIG_WRITE_INSTANT)
                    {
                        bs->mark_stable(ov);
                    }
                }
            }
            else if (je->type == JE_STABLE)
            {
 #ifdef BLOCKSTORE_DEBUG
-                printf("je_stable oid=%lx:%lx ver=%lu\n", je->stable.oid.inode, je->stable.oid.stripe, je->stable.version);
+                printf("je_stable oid=%lu:%lu ver=%lu\n", je->stable.oid.inode, je->stable.oid.stripe, je->stable.version);
 #endif
                // oid, version
                obj_ver_id ov = {
                    .oid = je->stable.oid,
                    .version = je->stable.version,
                };
-                bs->mark_stable(ov);
+                auto it = bs->dirty_db.find(ov);
                if (it == bs->dirty_db.end())
                {
                    // journal contains a legitimate STABLE entry for a non-existing dirty write
                    // this probably means that journal was trimmed between WRITE and STABLE entries
                    // skip it
                }
                else
                {
                    while (1)
                    {
                        it->second.state = (it->second.state == ST_D_META_SYNCED
                            ? ST_D_STABLE
                            : (it->second.state == ST_DEL_SYNCED ? ST_DEL_STABLE : ST_J_STABLE));
                        if (it == bs->dirty_db.begin())
                            break;
                        it--;
                        if (it->first.oid != ov.oid || IS_STABLE(it->second.state))
                            break;
                    }
                    bs->flusher->enqueue_flush(ov);
                }
                auto unstab_it = bs->unstable_writes.find(ov.oid);
                if (unstab_it != bs->unstable_writes.end() && unstab_it->second <= ov.version)
                {
                    bs->unstable_writes.erase(unstab_it);
                }
            }
            else if (je->type == JE_ROLLBACK)
            {
 #ifdef BLOCKSTORE_DEBUG
-                printf("je_rollback oid=%lx:%lx ver=%lu\n", je->rollback.oid.inode, je->rollback.oid.stripe, je->rollback.version);
+                printf("je_rollback oid=%lu:%lu ver=%lu\n", je->rollback.oid.inode, je->rollback.oid.stripe, je->rollback.version);
 #endif
                // rollback dirty writes of <oid> up to <version>
-                obj_ver_id ov = {
+                auto it = bs->dirty_db.lower_bound((obj_ver_id){
                    .oid = je->rollback.oid,
-                    .version = je->rollback.version,
+                    .version = UINT64_MAX,
-                };
+                });
-                bs->mark_rolled_back(ov);
+                if (it != bs->dirty_db.begin())
                {
                    uint64_t max_unstable = 0;
                    auto rm_start = it;
                    auto rm_end = it;
                    it--;
                    while (it->first.oid == je->rollback.oid &&
                        it->first.version > je->rollback.version &&
                        !IS_IN_FLIGHT(it->second.state) &&
                        !IS_STABLE(it->second.state))
                    {
                        if (it->first.oid != je->rollback.oid)
                            break;
                        else if (it->first.version <= je->rollback.version)
                        {
                            if (!IS_STABLE(it->second.state))
                                max_unstable = it->first.version;
                            break;
                        }
                        else if (IS_STABLE(it->second.state))
                            break;
                        // Remove entry
                        rm_start = it;
                        if (it == bs->dirty_db.begin())
                            break;
                        it--;
                    }
                    if (rm_start != rm_end)
                    {
                        bs->erase_dirty(rm_start, rm_end, UINT64_MAX);
                    }
                    auto unstab_it = bs->unstable_writes.find(je->rollback.oid);
                    if (unstab_it != bs->unstable_writes.end())
                    {
                        if (max_unstable == 0)
                            bs->unstable_writes.erase(unstab_it);
                        else
                            unstab_it->second = max_unstable;
                    }
                }
            }
            else if (je->type == JE_DELETE)
            {
 #ifdef BLOCKSTORE_DEBUG
-                printf("je_delete oid=%lx:%lx ver=%lu\n", je->del.oid.inode, je->del.oid.stripe, je->del.version);
+                printf("je_delete oid=%lu:%lu ver=%lu\n", je->del.oid.inode, je->del.oid.stripe, je->del.version);
 #endif
-                auto clean_it = bs->clean_db.find(je->del.oid);
+                // oid, version
-                if (clean_it == bs->clean_db.end() ||
+                obj_ver_id ov = {
-                    clean_it->second.version < je->del.version)
+                    .oid = je->del.oid,
-                {
+                    .version = je->del.version,
-                    // oid, version
+                };
-                    obj_ver_id ov = {
+                bs->dirty_db.emplace(ov, (dirty_entry){
-                        .oid = je->del.oid,
+                    .state = ST_DEL_SYNCED,
-                        .version = je->del.version,
+                    .flags = 0,
-                    };
+                    .location = 0,
-                    bs->dirty_db.emplace(ov, (dirty_entry){
+                    .offset = 0,
-                        .state = (BS_ST_DELETE | BS_ST_SYNCED),
+                    .len = 0,
-                        .flags = 0,
+                    .journal_sector = proc_pos,
-                        .location = 0,
+                });
-                        .offset = 0,
+                bs->journal.used_sectors[proc_pos]++;
                        .len = 0,
                        .journal_sector = proc_pos,
                    });
                    bs->journal.used_sectors[proc_pos]++;
                    // Deletions are treated as immediately stable, because
                    // "2-phase commit" (write->stabilize) isn't sufficient for them anyway
                    bs->mark_stable(ov);
                }
            }
            started = true;
            pos += je->size;
--- a/blockstore_init.h
+++ b/blockstore_init.h
@ -1,6 +1,3 @@
 // Copyright (c) Vitaliy Filippov, 2019+
 // License: VNPL-1.0 (see README.md for details)
 #pragma once
 class blockstore_init_meta
--- a/blockstore_journal.cpp
+++ b/blockstore_journal.cpp
@ -1,6 +1,3 @@
 // Copyright (c) Vitaliy Filippov, 2019+
 // License: VNPL-1.0 (see README.md for details)
 #include "blockstore_impl.h"
 blockstore_journal_check_t::blockstore_journal_check_t(blockstore_impl_t *bs)
@ -9,26 +6,18 @@ blockstore_journal_check_t::blockstore_journal_check_t(blockstore_impl_t *bs)
    sectors_required = 0;
    next_pos = bs->journal.next_free;
    next_sector = bs->journal.cur_sector;
    first_sector = -1;
    next_in_pos = bs->journal.in_sector_pos;
    right_dir = next_pos >= bs->journal.used_start;
 }
 // Check if we can write <required> entries of <size> bytes and <data_after> data bytes after them to the journal
-int blockstore_journal_check_t::check_available(blockstore_op_t *op, int entries_required, int size, int data_after)
+int blockstore_journal_check_t::check_available(blockstore_op_t *op, int required, int size, int data_after)
 {
    int required = entries_required;
    while (1)
    {
-        int fits = bs->journal.no_same_sector_overwrites && bs->journal.sector_info[next_sector].written
+        int fits = (bs->journal.block_size - next_in_pos) / size;
            ? 0
            : (bs->journal.block_size - next_in_pos) / size;
        if (fits > 0)
        {
            if (first_sector == -1)
            {
                first_sector = next_sector;
            }
            required -= fits;
            next_in_pos += fits * size;
            sectors_required++;
@ -49,40 +38,19 @@ int blockstore_journal_check_t::check_available(blockstore_op_t *op, int entries
            right_dir = false;
        }
        next_in_pos = 0;
-        next_sector = ((next_sector + 1) % bs->journal.sector_count);
+        if (bs->journal.sector_info[next_sector].usage_count > 0 ||
-        if (next_sector == first_sector)
+            bs->journal.sector_info[next_sector].dirty)
        {
-            // next_sector may wrap when all sectors are flushed and the incoming batch is too big
+            next_sector = ((next_sector + 1) % bs->journal.sector_count);
            // This is an error condition, we can't wait for anything in this case
            throw std::runtime_error(
                "Blockstore journal_sector_buffer_count="+std::to_string(bs->journal.sector_count)+
                " is too small for a batch of "+std::to_string(entries_required)+" entries of "+std::to_string(size)+" bytes"
            );
        }
        if (bs->journal.sector_info[next_sector].usage_count > 0 ||
            bs->journal.sector_info[next_sector].dirty)
        {
            // No memory buffer available. Wait for it.
-            int used = 0, dirty = 0;
+#ifdef BLOCKSTORE_DEBUG
-            for (int i = 0; i < bs->journal.sector_count; i++)
+            printf("next journal buffer %d is still dirty=%d used=%d\n", next_sector,
-            {
+                bs->journal.sector_info[next_sector].dirty, bs->journal.sector_info[next_sector].usage_count);
-                if (bs->journal.sector_info[i].dirty)
+#endif
                {
                    dirty++;
                    used++;
                }
                if (bs->journal.sector_info[i].usage_count > 0)
                {
                    used++;
                }
            }
            // In fact, it's even more rare than "ran out of journal space", so print a warning
            printf(
                "Ran out of journal sector buffers: %d/%lu buffers used (%d dirty), next buffer (%ld) is %s and flushed %lu times\n",
                used, bs->journal.sector_count, dirty, next_sector,
                bs->journal.sector_info[next_sector].dirty ? "dirty" : "not dirty",
                bs->journal.sector_info[next_sector].usage_count
            );
            PRIV(op)->wait_for = WAIT_JOURNAL_BUFFER;
            return 0;
        }
@ -106,7 +74,7 @@ int blockstore_journal_check_t::check_available(blockstore_op_t *op, int entries
                : bs->journal.used_start - bs->journal.next_free)
        );
        PRIV(op)->wait_for = WAIT_JOURNAL;
-        bs->flusher->request_trim();
+        bs->flusher->force_start();
        PRIV(op)->wait_detail = bs->journal.used_start;
        return 0;
    }
@ -115,21 +83,14 @@ int blockstore_journal_check_t::check_available(blockstore_op_t *op, int entries
 journal_entry* prefill_single_journal_entry(journal_t & journal, uint16_t type, uint32_t size)
 {
-    if (journal.block_size - journal.in_sector_pos < size ||
+    if (journal.block_size - journal.in_sector_pos < size)
        journal.no_same_sector_overwrites && journal.sector_info[journal.cur_sector].written)
    {
        assert(!journal.sector_info[journal.cur_sector].dirty);
        // Move to the next journal sector
        journal.sector_info[journal.cur_sector].written = false;
        if (journal.sector_info[journal.cur_sector].usage_count > 0)
        {
            // Also select next sector buffer in memory
            journal.cur_sector = ((journal.cur_sector + 1) % journal.sector_count);
            assert(!journal.sector_info[journal.cur_sector].usage_count);
        }
        else
        {
            journal.dirty_start = journal.next_free;
        }
        journal.sector_info[journal.cur_sector].offset = journal.next_free;
        journal.in_sector_pos = 0;
@ -155,7 +116,6 @@ journal_entry* prefill_single_journal_entry(journal_t & journal, uint16_t type,
 void prepare_journal_sector_write(journal_t & journal, int cur_sector, io_uring_sqe *sqe, std::function<void(ring_data_t*)> cb)
 {
    journal.sector_info[cur_sector].dirty = false;
    journal.sector_info[cur_sector].written = true;
    journal.sector_info[cur_sector].usage_count++;
    ring_data_t *data = ((ring_data_t*)sqe->user_data);
    data->iov = (struct iovec){
@ -166,8 +126,9 @@ void prepare_journal_sector_write(journal_t & journal, int cur_sector, io_uring_
    };
    data->callback = cb;
    my_uring_prep_writev(
-        sqe, journal.fd, &data->iov, 1, journal.offset + journal.sector_info[cur_sector].offset
+        sqe, journal.fd_index, &data->iov, 1, journal.offset + journal.sector_info[cur_sector].offset
    );
    sqe->flags |= IOSQE_FIXED_FILE;
 }
 journal_t::~journal_t()
@ -188,8 +149,8 @@ bool journal_t::trim()
    auto journal_used_it = used_sectors.lower_bound(used_start);
 #ifdef BLOCKSTORE_DEBUG
    printf(
-        "Trimming journal (used_start=%08lx, next_free=%08lx, dirty_start=%08lx, new_start=%08lx, new_refcount=%ld)\n",
+        "Trimming journal (used_start=%lu, next_free=%lu, first_used=%lu, usage_count=%lu)\n",
-        used_start, next_free, dirty_start,
+        used_start, next_free,
        journal_used_it == used_sectors.end() ? 0 : journal_used_it->first,
        journal_used_it == used_sectors.end() ? 0 : journal_used_it->second
    );
@ -220,7 +181,7 @@ bool journal_t::trim()
        return false;
    }
 #ifdef BLOCKSTORE_DEBUG
-    printf("Journal trimmed to %08lx (next_free=%08lx)\n", used_start, next_free);
+    printf("Journal trimmed to %lu (next_free=%lu)\n", used_start, next_free);
 #endif
    return true;
 }
--- a/blockstore_journal.h
+++ b/blockstore_journal.h
@ -1,6 +1,3 @@
 // Copyright (c) Vitaliy Filippov, 2019+
 // License: VNPL-1.0 (see README.md for details)
 #pragma once
 #include "crc32c.h"
@ -15,16 +12,12 @@
 // Journal entries
 // Journal entries are linked to each other by their crc32 value
 // The journal is almost a blockchain, because object versions constantly increase
 #define JE_MIN         0x01
 #define JE_START       0x01
 #define JE_SMALL_WRITE 0x02
 #define JE_BIG_WRITE   0x03
 #define JE_STABLE      0x04
 #define JE_DELETE      0x05
 #define JE_ROLLBACK    0x06
 #define JE_SMALL_WRITE_INSTANT 0x07
 #define JE_BIG_WRITE_INSTANT   0x08
 #define JE_MAX         0x08
 // crc32c comes first to ease calculation and is equal to crc32()
 struct __attribute__((__packed__)) journal_entry_start
@ -132,32 +125,26 @@ struct journal_sector_info_t
 {
    uint64_t offset;
    uint64_t usage_count;
    bool written;
    bool dirty;
 };
 struct journal_t
 {
-    int fd;
+    int fd, fd_index;
    uint64_t device_size;
    bool inmemory = false;
    void *buffer = NULL;
-    uint64_t block_size;
+    uint64_t block_size = 512;
    uint64_t offset, len;
    // Next free block offset
    uint64_t next_free = 0;
    // First occupied block offset
    uint64_t used_start = 0;
    // End of the last block not used for writing anymore
    uint64_t dirty_start = 0;
    uint32_t crc32_last = 0;
    // Current sector(s) used for writing
    void *sector_buf = NULL;
    journal_sector_info_t *sector_info = NULL;
    uint64_t sector_count;
    bool no_same_sector_overwrites = false;
    int cur_sector = 0;
    int in_sector_pos = 0;
@ -173,7 +160,7 @@ struct blockstore_journal_check_t
 {
    blockstore_impl_t *bs;
    uint64_t next_pos, next_sector, next_in_pos;
-    int sectors_required, first_sector;
+    int sectors_required;
    bool right_dir; // writing to the end or the beginning of the ring buffer
    blockstore_journal_check_t(blockstore_impl_t *bs);
--- a/blockstore_open.cpp
+++ b/blockstore_open.cpp
@ -1,7 +1,3 @@
 // Copyright (c) Vitaliy Filippov, 2019+
 // License: VNPL-1.0 (see README.md for details)
 #include <sys/file.h>
 #include "blockstore_impl.h"
 static uint32_t is_power_of_two(uint64_t value)
@ -38,23 +34,10 @@ void blockstore_impl_t::parse_config(blockstore_config_t & config)
    {
        disable_journal_fsync = true;
    }
    if (config["disable_device_lock"] == "true" || config["disable_device_lock"] == "1" || config["disable_device_lock"] == "yes")
    {
        disable_flock = true;
    }
    if (config["immediate_commit"] == "all")
    {
        immediate_commit = IMMEDIATE_ALL;
    }
    else if (config["immediate_commit"] == "small")
    {
        immediate_commit = IMMEDIATE_SMALL;
    }
    metadata_buf_size = strtoull(config["meta_buf_size"].c_str(), NULL, 10);
    cfg_journal_size = strtoull(config["journal_size"].c_str(), NULL, 10);
    data_device = config["data_device"];
    data_offset = strtoull(config["data_offset"].c_str(), NULL, 10);
    cfg_data_size = strtoull(config["data_size"].c_str(), NULL, 10);
    meta_device = config["meta_device"];
    meta_offset = strtoull(config["meta_offset"].c_str(), NULL, 10);
    block_size = strtoull(config["block_size"].c_str(), NULL, 10);
@ -62,8 +45,6 @@ void blockstore_impl_t::parse_config(blockstore_config_t & config)
    journal_device = config["journal_device"];
    journal.offset = strtoull(config["journal_offset"].c_str(), NULL, 10);
    journal.sector_count = strtoull(config["journal_sector_buffer_count"].c_str(), NULL, 10);
    journal.no_same_sector_overwrites = config["journal_no_same_sector_overwrites"] == "true" ||
        config["journal_no_same_sector_overwrites"] == "1" || config["journal_no_same_sector_overwrites"] == "yes";
    journal.inmemory = config["inmemory_journal"] != "false";
    disk_alignment = strtoull(config["disk_alignment"].c_str(), NULL, 10);
    journal_block_size = strtoull(config["journal_block_size"].c_str(), NULL, 10);
@ -85,7 +66,7 @@ void blockstore_impl_t::parse_config(blockstore_config_t & config)
    }
    if (!disk_alignment)
    {
-        disk_alignment = 4096;
+        disk_alignment = 512;
    }
    else if (disk_alignment % MEM_ALIGNMENT)
    {
@ -93,7 +74,7 @@ void blockstore_impl_t::parse_config(blockstore_config_t & config)
    }
    if (!journal_block_size)
    {
-        journal_block_size = 4096;
+        journal_block_size = 512;
    }
    else if (journal_block_size % MEM_ALIGNMENT)
    {
@ -101,7 +82,7 @@ void blockstore_impl_t::parse_config(blockstore_config_t & config)
    }
    if (!meta_block_size)
    {
-        meta_block_size = 4096;
+        meta_block_size = 512;
    }
    else if (meta_block_size % MEM_ALIGNMENT)
    {
@ -147,22 +128,6 @@ void blockstore_impl_t::parse_config(blockstore_config_t & config)
    {
        metadata_buf_size = 4*1024*1024;
    }
    if (meta_device == "")
    {
        disable_meta_fsync = disable_data_fsync;
    }
    if (journal_device == "")
    {
        disable_journal_fsync = disable_meta_fsync;
    }
    if (immediate_commit != IMMEDIATE_NONE && !disable_journal_fsync)
    {
        throw std::runtime_error("immediate_commit requires disable_journal_fsync");
    }
    if (immediate_commit == IMMEDIATE_ALL && !disable_data_fsync)
    {
        throw std::runtime_error("immediate_commit=all requires disable_journal_fsync and disable_data_fsync");
    }
    // init some fields
    clean_entry_bitmap_size = block_size / bitmap_granularity / 8;
    clean_entry_size = sizeof(clean_disk_entry) + clean_entry_bitmap_size;
@ -175,6 +140,10 @@ void blockstore_impl_t::parse_config(blockstore_config_t & config)
 void blockstore_impl_t::calc_lengths()
 {
    // register fds
    data_fd_index = ringloop->register_fd(data_fd);
    meta_fd_index = meta_fd == data_fd ? data_fd_index : ringloop->register_fd(meta_fd);
    journal.fd_index = journal_fd_index = journal.fd == meta_fd ? meta_fd_index : ringloop->register_fd(journal.fd);
    // data
    data_len = data_size - data_offset;
    if (data_fd == meta_fd && data_offset < meta_offset)
@ -186,15 +155,6 @@ void blockstore_impl_t::calc_lengths()
        data_len = data_len < journal.offset-data_offset
            ? data_len : journal.offset-data_offset;
    }
    if (cfg_data_size != 0)
    {
        if (data_len < cfg_data_size)
        {
            throw std::runtime_error("Data area ("+std::to_string(data_len)+
                " bytes) is less than configured size ("+std::to_string(cfg_data_size)+" bytes)");
        }
        data_len = cfg_data_size;
    }
    // meta
    meta_area = (meta_fd == data_fd ? data_size : meta_size) - meta_offset;
    if (meta_fd == data_fd && meta_offset <= data_offset)
@ -296,10 +256,6 @@ void blockstore_impl_t::open_data()
    {
        throw std::runtime_error("data_offset exceeds device size = "+std::to_string(data_size));
    }
    if (!disable_flock && flock(data_fd, LOCK_EX|LOCK_NB) != 0)
    {
        throw std::runtime_error(std::string("Failed to lock data device: ") + strerror(errno));
    }
 }
 void blockstore_impl_t::open_meta()
@ -317,14 +273,11 @@ void blockstore_impl_t::open_meta()
        {
            throw std::runtime_error("meta_offset exceeds device size = "+std::to_string(meta_size));
        }
        if (!disable_flock && flock(meta_fd, LOCK_EX|LOCK_NB) != 0)
        {
            throw std::runtime_error(std::string("Failed to lock metadata device: ") + strerror(errno));
        }
    }
    else
    {
        meta_fd = data_fd;
        disable_meta_fsync = disable_data_fsync;
        meta_size = 0;
        if (meta_offset >= data_size)
        {
@ -342,15 +295,12 @@ void blockstore_impl_t::open_journal()
        {
            throw std::runtime_error("Failed to open journal device");
        }
-        check_size(journal.fd, &journal.device_size, "journal device");
+        check_size(journal.fd, &journal.device_size, "metadata device");
        if (!disable_flock && flock(journal.fd, LOCK_EX|LOCK_NB) != 0)
        {
            throw std::runtime_error(std::string("Failed to lock journal device: ") + strerror(errno));
        }
    }
    else
    {
        journal.fd = meta_fd;
        disable_journal_fsync = disable_meta_fsync;
        journal.device_size = 0;
        if (journal.offset >= data_size)
        {
--- a/blockstore_read.cpp
+++ b/blockstore_read.cpp
@ -1,6 +1,3 @@
 // Copyright (c) Vitaliy Filippov, 2019+
 // License: VNPL-1.0 (see README.md for details)
 #include "blockstore_impl.h"
 int blockstore_impl_t::fulfill_read_push(blockstore_op_t *op, void *buf, uint64_t offset, uint64_t len,
@ -11,10 +8,12 @@ int blockstore_impl_t::fulfill_read_push(blockstore_op_t *op, void *buf, uint64_
        // Zero-length version - skip
        return 1;
    }
-    else if (IS_IN_FLIGHT(item_state))
+    if (IS_IN_FLIGHT(item_state))
    {
-        // Write not finished yet - skip
+        // Pause until it's written somewhere
-        return 1;
+        PRIV(op)->wait_for = WAIT_IN_FLIGHT;
        PRIV(op)->wait_detail = item_version;
        return 0;
    }
    else if (IS_DELETE(item_state))
    {
@ -32,15 +31,15 @@ int blockstore_impl_t::fulfill_read_push(blockstore_op_t *op, void *buf, uint64_
    PRIV(op)->pending_ops++;
    my_uring_prep_readv(
        sqe,
-        IS_JOURNAL(item_state) ? journal.fd : data_fd,
+        IS_JOURNAL(item_state) ? journal_fd_index : data_fd_index,
        &data->iov, 1,
        (IS_JOURNAL(item_state) ? journal.offset : data_offset) + offset
    );
    sqe->flags |= IOSQE_FIXED_FILE;
    data->callback = [this, op](ring_data_t *data) { handle_read_event(data, op); };
    return 1;
 }
 // FIXME I've seen a bug here so I want some tests
 int blockstore_impl_t::fulfill_read(blockstore_op_t *read_op, uint64_t &fulfilled, uint32_t item_start, uint32_t item_end,
    uint32_t item_state, uint64_t item_version, uint64_t item_location)
 {
@ -53,20 +52,8 @@ int blockstore_impl_t::fulfill_read(blockstore_op_t *read_op, uint64_t &fulfille
        while (1)
        {
            for (; it != PRIV(read_op)->read_vec.end(); it++)
            {
                if (it->offset >= cur_start)
                {
                    break;
                }
                else if (it->offset + it->len > cur_start)
                {
                    cur_start = it->offset + it->len;
                    if (cur_start >= item_end)
                    {
                        goto endwhile;
                    }
                }
            }
            if (it == PRIV(read_op)->read_vec.end() || it->offset > cur_start)
            {
                fulfill_read_t el = {
@ -85,12 +72,9 @@ int blockstore_impl_t::fulfill_read(blockstore_op_t *read_op, uint64_t &fulfille
            }
            cur_start = it->offset + it->len;
            if (it == PRIV(read_op)->read_vec.end() || cur_start >= item_end)
            {
                break;
            }
        }
    }
 endwhile:
    return 1;
 }
@ -150,67 +134,63 @@ int blockstore_impl_t::dequeue_read(blockstore_op_t *read_op)
            dirty_it--;
        }
    }
-    if (clean_it != clean_db.end())
+    if (clean_it != clean_db.end() && fulfilled < read_op->len)
    {
        if (!result_version)
        {
            result_version = clean_it->second.version;
        }
-        if (fulfilled < read_op->len)
+        if (!clean_entry_bitmap_size)
        {
-            if (!clean_entry_bitmap_size)
+            if (!fulfill_read(read_op, fulfilled, 0, block_size, ST_CURRENT, 0, clean_it->second.location))
            {
-                if (!fulfill_read(read_op, fulfilled, 0, block_size, (BS_ST_BIG_WRITE | BS_ST_STABLE), 0, clean_it->second.location))
+                // need to wait. undo added requests, don't dequeue op
-                {
+                PRIV(read_op)->read_vec.clear();
-                    // need to wait. undo added requests, don't dequeue op
+                return 0;
-                    PRIV(read_op)->read_vec.clear();
+            }
-                    return 0;
+        }
-                }
+        else
        {
            uint64_t meta_loc = clean_it->second.location >> block_order;
            uint8_t *clean_entry_bitmap;
            if (inmemory_meta)
            {
                uint64_t sector = (meta_loc / (meta_block_size / clean_entry_size)) * meta_block_size;
                uint64_t pos = (meta_loc % (meta_block_size / clean_entry_size));
                clean_entry_bitmap = (uint8_t*)(metadata_buffer + sector + pos*clean_entry_size + sizeof(clean_disk_entry));
            }
            else
            {
-                uint64_t meta_loc = clean_it->second.location >> block_order;
+                clean_entry_bitmap = (uint8_t*)(clean_bitmap + meta_loc*clean_entry_bitmap_size);
-                uint8_t *clean_entry_bitmap;
+            }
-                if (inmemory_meta)
+            uint64_t bmp_start = 0, bmp_end = 0, bmp_size = block_size/bitmap_granularity;
            while (bmp_start < bmp_size)
            {
                while (!(clean_entry_bitmap[bmp_end >> 3] & (1 << (bmp_end & 0x7))) && bmp_end < bmp_size)
                {
-                    uint64_t sector = (meta_loc / (meta_block_size / clean_entry_size)) * meta_block_size;
+                    bmp_end++;
                    uint64_t pos = (meta_loc % (meta_block_size / clean_entry_size));
                    clean_entry_bitmap = (uint8_t*)(metadata_buffer + sector + pos*clean_entry_size + sizeof(clean_disk_entry));
                }
-                else
+                if (bmp_end > bmp_start)
                {
-                    clean_entry_bitmap = (uint8_t*)(clean_bitmap + meta_loc*clean_entry_bitmap_size);
+                    // fill with zeroes
                    fulfill_read(read_op, fulfilled, bmp_start * bitmap_granularity,
                        bmp_end * bitmap_granularity, ST_DEL_STABLE, 0, 0);
                }
-                uint64_t bmp_start = 0, bmp_end = 0, bmp_size = block_size/bitmap_granularity;
+                bmp_start = bmp_end;
-                while (bmp_start < bmp_size)
+                while (clean_entry_bitmap[bmp_end >> 3] & (1 << (bmp_end & 0x7)) && bmp_end < bmp_size)
                {
-                    while (!(clean_entry_bitmap[bmp_end >> 3] & (1 << (bmp_end & 0x7))) && bmp_end < bmp_size)
+                    bmp_end++;
                }
                if (bmp_end > bmp_start)
                {
                    if (!fulfill_read(read_op, fulfilled, bmp_start * bitmap_granularity,
                        bmp_end * bitmap_granularity, ST_CURRENT, 0, clean_it->second.location + bmp_start * bitmap_granularity))
                    {
-                        bmp_end++;
+                        // need to wait. undo added requests, don't dequeue op
-                    }
+                        PRIV(read_op)->read_vec.clear();
-                    if (bmp_end > bmp_start)
+                        return 0;
                    {
                        // fill with zeroes
                        fulfill_read(read_op, fulfilled, bmp_start * bitmap_granularity,
                            bmp_end * bitmap_granularity, (BS_ST_DELETE | BS_ST_STABLE), 0, 0);
                    }
                    bmp_start = bmp_end;
                    while (clean_entry_bitmap[bmp_end >> 3] & (1 << (bmp_end & 0x7)) && bmp_end < bmp_size)
                    {
                        bmp_end++;
                    }
                    if (bmp_end > bmp_start)
                    {
                        if (!fulfill_read(read_op, fulfilled, bmp_start * bitmap_granularity,
                            bmp_end * bitmap_granularity, (BS_ST_BIG_WRITE | BS_ST_STABLE), 0,
                            clean_it->second.location + bmp_start * bitmap_granularity))
                        {
                            // need to wait. undo added requests, don't dequeue op
                            PRIV(read_op)->read_vec.clear();
                            return 0;
                        }
                        bmp_start = bmp_end;
                    }
                }
            }
        }
@ -218,7 +198,7 @@ int blockstore_impl_t::dequeue_read(blockstore_op_t *read_op)
    else if (fulfilled < read_op->len)
    {
        // fill remaining parts with zeroes
-        fulfill_read(read_op, fulfilled, 0, block_size, (BS_ST_DELETE | BS_ST_STABLE), 0, 0);
+        fulfill_read(read_op, fulfilled, 0, block_size, ST_DEL_STABLE, 0, 0);
    }
    assert(fulfilled == read_op->len);
    read_op->version = result_version;
--- a/blockstore_rollback.cpp
+++ b/blockstore_rollback.cpp
@ -1,14 +1,7 @@
 // Copyright (c) Vitaliy Filippov, 2019+
 // License: VNPL-1.0 (see README.md for details)
 #include "blockstore_impl.h"
 int blockstore_impl_t::dequeue_rollback(blockstore_op_t *op)
 {
    if (PRIV(op)->op_state)
    {
        return continue_rollback(op);
    }
    obj_ver_id* v;
    int i, todo = op->len;
    for (i = 0, v = (obj_ver_id*)op->buf; i < op->len; i++, v++)
@ -21,13 +14,8 @@ int blockstore_impl_t::dequeue_rollback(blockstore_op_t *op)
        });
        if (dirty_it == dirty_db.begin())
        {
            if (v->version == 0)
            {
                // Already rolled back
                // FIXME Skip this object version
            }
        bad_op:
-            op->retval = -ENOENT;
+            op->retval = -EINVAL;
            FINISH_OP(op);
            return 1;
        }
@ -43,9 +31,7 @@ int blockstore_impl_t::dequeue_rollback(blockstore_op_t *op)
                if (!IS_SYNCED(dirty_it->second.state) ||
                    IS_STABLE(dirty_it->second.state))
                {
-                    op->retval = -EBUSY;
+                    goto bad_op;
                    FINISH_OP(op);
                    return 1;
                }
                if (dirty_it == dirty_db.begin())
                {
@ -74,12 +60,39 @@ int blockstore_impl_t::dequeue_rollback(blockstore_op_t *op)
        journal.sector_info[journal.cur_sector].dirty)
    {
        if (cur_sector == -1)
-            PRIV(op)->min_flushed_journal_sector = 1 + journal.cur_sector;
+            PRIV(op)->min_used_journal_sector = 1 + journal.cur_sector;
        cur_sector = journal.cur_sector;
        prepare_journal_sector_write(journal, cur_sector, sqe[s++], cb);
    }
    for (i = 0, v = (obj_ver_id*)op->buf; i < op->len; i++, v++)
    {
        // FIXME This is here only for the purpose of tracking unstable_writes. Remove if not required
        // FIXME ...aaaand this is similar to blockstore_init.cpp - maybe dedup it?
        auto dirty_it = dirty_db.lower_bound((obj_ver_id){
            .oid = v->oid,
            .version = UINT64_MAX,
        });
        uint64_t max_unstable = 0;
        while (dirty_it != dirty_db.begin())
        {
            dirty_it--;
            if (dirty_it->first.oid != v->oid)
                break;
            else if (dirty_it->first.version <= v->version)
            {
                if (!IS_STABLE(dirty_it->second.state))
                    max_unstable = dirty_it->first.version;
                break;
            }
        }
        auto unstab_it = unstable_writes.find(v->oid);
        if (unstab_it != unstable_writes.end())
        {
            if (max_unstable == 0)
                unstable_writes.erase(unstab_it);
            else
                unstab_it->second = max_unstable;
        }
        journal_entry_rollback *je = (journal_entry_rollback*)
            prefill_single_journal_entry(journal, JE_ROLLBACK, sizeof(journal_entry_rollback));
        journal.sector_info[journal.cur_sector].dirty = false;
@ -90,117 +103,21 @@ int blockstore_impl_t::dequeue_rollback(blockstore_op_t *op)
        if (cur_sector != journal.cur_sector)
        {
            if (cur_sector == -1)
-                PRIV(op)->min_flushed_journal_sector = 1 + journal.cur_sector;
+                PRIV(op)->min_used_journal_sector = 1 + journal.cur_sector;
            cur_sector = journal.cur_sector;
            prepare_journal_sector_write(journal, cur_sector, sqe[s++], cb);
        }
    }
-    PRIV(op)->max_flushed_journal_sector = 1 + journal.cur_sector;
+    PRIV(op)->max_used_journal_sector = 1 + journal.cur_sector;
    PRIV(op)->pending_ops = s;
    PRIV(op)->op_state = 1;
    inflight_writes++;
    return 1;
 }
 int blockstore_impl_t::continue_rollback(blockstore_op_t *op)
 {
    if (PRIV(op)->op_state == 2)
        goto resume_2;
    else if (PRIV(op)->op_state == 3)
        goto resume_3;
    else if (PRIV(op)->op_state == 5)
        goto resume_5;
    else
        return 1;
 resume_2:
    // Release used journal sectors
    release_journal_sectors(op);
 resume_3:
    if (!disable_journal_fsync)
    {
        io_uring_sqe *sqe = get_sqe();
        if (!sqe)
        {
            return 0;
        }
        ring_data_t *data = ((ring_data_t*)sqe->user_data);
        my_uring_prep_fsync(sqe, journal.fd, IORING_FSYNC_DATASYNC);
        data->iov = { 0 };
        data->callback = [this, op](ring_data_t *data) { handle_rollback_event(data, op); };
        PRIV(op)->min_flushed_journal_sector = PRIV(op)->max_flushed_journal_sector = 0;
        PRIV(op)->pending_ops = 1;
        PRIV(op)->op_state = 4;
        return 1;
    }
 resume_5:
    obj_ver_id* v;
    int i;
    for (i = 0, v = (obj_ver_id*)op->buf; i < op->len; i++, v++)
    {
        mark_rolled_back(*v);
    }
    journal.trim();
    inflight_writes--;
    // Acknowledge op
    op->retval = 0;
    FINISH_OP(op);
    return 1;
 }
 void blockstore_impl_t::mark_rolled_back(const obj_ver_id & ov)
 {
    auto it = dirty_db.lower_bound((obj_ver_id){
        .oid = ov.oid,
        .version = UINT64_MAX,
    });
    if (it != dirty_db.begin())
    {
        uint64_t max_unstable = 0;
        auto rm_start = it;
        auto rm_end = it;
        it--;
        while (it->first.oid == ov.oid &&
            it->first.version > ov.version &&
            !IS_IN_FLIGHT(it->second.state) &&
            !IS_STABLE(it->second.state))
        {
            if (it->first.oid != ov.oid)
                break;
            else if (it->first.version <= ov.version)
            {
                if (!IS_STABLE(it->second.state))
                    max_unstable = it->first.version;
                break;
            }
            else if (IS_STABLE(it->second.state))
                break;
            // Remove entry
            rm_start = it;
            if (it == dirty_db.begin())
                break;
            it--;
        }
        if (rm_start != rm_end)
        {
            erase_dirty(rm_start, rm_end, UINT64_MAX);
        }
        auto unstab_it = unstable_writes.find(ov.oid);
        if (unstab_it != unstable_writes.end())
        {
            if (max_unstable == 0)
                unstable_writes.erase(unstab_it);
            else
                unstab_it->second = max_unstable;
        }
    }
 }
 void blockstore_impl_t::handle_rollback_event(ring_data_t *data, blockstore_op_t *op)
 {
    live = true;
    if (data->res != data->iov.iov_len)
    {
        inflight_writes--;
        throw std::runtime_error(
            "write operation failed ("+std::to_string(data->res)+" != "+std::to_string(data->iov.iov_len)+
            "). in-memory state is corrupted. AAAAAAAaaaaaaaaa!!!111"
@ -209,11 +126,37 @@ void blockstore_impl_t::handle_rollback_event(ring_data_t *data, blockstore_op_t
    PRIV(op)->pending_ops--;
    if (PRIV(op)->pending_ops == 0)
    {
-        PRIV(op)->op_state++;
+        // Release used journal sectors
-        if (!continue_rollback(op))
+        release_journal_sectors(op);
        obj_ver_id* v;
        int i;
        for (i = 0, v = (obj_ver_id*)op->buf; i < op->len; i++, v++)
        {
-            submit_queue.push_front(op);
+            // Erase dirty_db entries
            auto rm_end = dirty_db.lower_bound((obj_ver_id){
                .oid = v->oid,
                .version = UINT64_MAX,
            });
            rm_end--;
            auto rm_start = rm_end;
            while (1)
            {
                if (rm_end->first.oid != v->oid)
                    break;
                else if (rm_end->first.version <= v->version)
                    break;
                rm_start = rm_end;
                if (rm_end == dirty_db.begin())
                    break;
                rm_end--;
            }
            if (rm_end != rm_start)
                erase_dirty(rm_start, rm_end, UINT64_MAX);
        }
        journal.trim();
        // Acknowledge op
        op->retval = 0;
        FINISH_OP(op);
    }
 }
@ -230,13 +173,11 @@ void blockstore_impl_t::erase_dirty(blockstore_dirty_db_t::iterator dirty_start,
 #endif
            data_alloc->set(dirty_it->second.location >> block_order, false);
        }
        int used = --journal.used_sectors[dirty_it->second.journal_sector];
 #ifdef BLOCKSTORE_DEBUG
-        printf(
+        printf("remove usage of journal offset %lu by %lu:%lu v%lu\n", dirty_it->second.journal_sector,
-            "remove usage of journal offset %08lx by %lx:%lx v%lu (%d refs)\n", dirty_it->second.journal_sector,
+            dirty_it->first.oid.inode, dirty_it->first.oid.stripe, dirty_it->first.version);
            dirty_it->first.oid.inode, dirty_it->first.oid.stripe, dirty_it->first.version, used
        );
 #endif
        int used = --journal.used_sectors[dirty_it->second.journal_sector];
        if (used == 0)
        {
            journal.used_sectors.erase(dirty_it->second.journal_sector);
--- a/blockstore_stable.cpp
+++ b/blockstore_stable.cpp
@ -1,6 +1,3 @@
 // Copyright (c) Vitaliy Filippov, 2019+
 // License: VNPL-1.0 (see README.md for details)
 #include "blockstore_impl.h"
 // Stabilize small write:
@ -43,10 +40,6 @@
 int blockstore_impl_t::dequeue_stable(blockstore_op_t *op)
 {
    if (PRIV(op)->op_state)
    {
        return continue_stable(op);
    }
    obj_ver_id* v;
    int i, todo = 0;
    for (i = 0, v = (obj_ver_id*)op->buf; i < op->len; i++, v++)
@ -58,7 +51,7 @@ int blockstore_impl_t::dequeue_stable(blockstore_op_t *op)
            if (clean_it == clean_db.end() || clean_it->second.version < v->version)
            {
                // No such object version
-                op->retval = -ENOENT;
+                op->retval = -EINVAL;
                FINISH_OP(op);
                return 1;
            }
@ -67,10 +60,10 @@ int blockstore_impl_t::dequeue_stable(blockstore_op_t *op)
                // Already stable
            }
        }
-        else if (!IS_SYNCED(dirty_it->second.state))
+        else if (IS_UNSYNCED(dirty_it->second.state))
        {
            // Object not synced yet. Caller must sync it first
-            op->retval = -EBUSY;
+            op->retval = EAGAIN;
            FINISH_OP(op);
            return 1;
        }
@ -105,13 +98,18 @@ int blockstore_impl_t::dequeue_stable(blockstore_op_t *op)
        journal.sector_info[journal.cur_sector].dirty)
    {
        if (cur_sector == -1)
-            PRIV(op)->min_flushed_journal_sector = 1 + journal.cur_sector;
+            PRIV(op)->min_used_journal_sector = 1 + journal.cur_sector;
        cur_sector = journal.cur_sector;
        prepare_journal_sector_write(journal, cur_sector, sqe[s++], cb);
    }
    for (i = 0, v = (obj_ver_id*)op->buf; i < op->len; i++, v++)
    {
-        // FIXME: Only stabilize versions that aren't stable yet
+        auto unstab_it = unstable_writes.find(v->oid);
        if (unstab_it != unstable_writes.end() &&
            unstab_it->second <= v->version)
        {
            unstable_writes.erase(unstab_it);
        }
        journal_entry_stable *je = (journal_entry_stable*)
            prefill_single_journal_entry(journal, JE_STABLE, sizeof(journal_entry_stable));
        journal.sector_info[journal.cur_sector].dirty = false;
@ -122,108 +120,21 @@ int blockstore_impl_t::dequeue_stable(blockstore_op_t *op)
        if (cur_sector != journal.cur_sector)
        {
            if (cur_sector == -1)
-                PRIV(op)->min_flushed_journal_sector = 1 + journal.cur_sector;
+                PRIV(op)->min_used_journal_sector = 1 + journal.cur_sector;
            cur_sector = journal.cur_sector;
            prepare_journal_sector_write(journal, cur_sector, sqe[s++], cb);
        }
    }
-    PRIV(op)->max_flushed_journal_sector = 1 + journal.cur_sector;
+    PRIV(op)->max_used_journal_sector = 1 + journal.cur_sector;
    PRIV(op)->pending_ops = s;
    PRIV(op)->op_state = 1;
    inflight_writes++;
    return 1;
 }
 int blockstore_impl_t::continue_stable(blockstore_op_t *op)
 {
    if (PRIV(op)->op_state == 2)
        goto resume_2;
    else if (PRIV(op)->op_state == 3)
        goto resume_3;
    else if (PRIV(op)->op_state == 5)
        goto resume_5;
    else
        return 1;
 resume_2:
    // Release used journal sectors
    release_journal_sectors(op);
 resume_3:
    if (!disable_journal_fsync)
    {
        io_uring_sqe *sqe = get_sqe();
        if (!sqe)
        {
            return 0;
        }
        ring_data_t *data = ((ring_data_t*)sqe->user_data);
        my_uring_prep_fsync(sqe, journal.fd, IORING_FSYNC_DATASYNC);
        data->iov = { 0 };
        data->callback = [this, op](ring_data_t *data) { handle_stable_event(data, op); };
        PRIV(op)->min_flushed_journal_sector = PRIV(op)->max_flushed_journal_sector = 0;
        PRIV(op)->pending_ops = 1;
        PRIV(op)->op_state = 4;
        return 1;
    }
 resume_5:
    // Mark dirty_db entries as stable, acknowledge op completion
    obj_ver_id* v;
    int i;
    for (i = 0, v = (obj_ver_id*)op->buf; i < op->len; i++, v++)
    {
        // Mark all dirty_db entries up to op->version as stable
        mark_stable(*v);
    }
    inflight_writes--;
    // Acknowledge op
    op->retval = 0;
    FINISH_OP(op);
    return 1;
 }
 void blockstore_impl_t::mark_stable(const obj_ver_id & v)
 {
    auto dirty_it = dirty_db.find(v);
    if (dirty_it != dirty_db.end())
    {
        while (1)
        {
            if ((dirty_it->second.state & BS_ST_WORKFLOW_MASK) == BS_ST_SYNCED)
            {
                dirty_it->second.state = (dirty_it->second.state & ~BS_ST_WORKFLOW_MASK) | BS_ST_STABLE;
            }
            else if (IS_STABLE(dirty_it->second.state))
            {
                break;
            }
            if (dirty_it == dirty_db.begin())
            {
                break;
            }
            dirty_it--;
            if (dirty_it->first.oid != v.oid)
            {
                break;
            }
        }
 #ifdef BLOCKSTORE_DEBUG
        printf("enqueue_flush %lx:%lx v%lu\n", v.oid.inode, v.oid.stripe, v.version);
 #endif
        flusher->enqueue_flush(v);
    }
    auto unstab_it = unstable_writes.find(v.oid);
    if (unstab_it != unstable_writes.end() &&
        unstab_it->second <= v.version)
    {
        unstable_writes.erase(unstab_it);
    }
 }
 void blockstore_impl_t::handle_stable_event(ring_data_t *data, blockstore_op_t *op)
 {
    live = true;
    if (data->res != data->iov.iov_len)
    {
        inflight_writes--;
        throw std::runtime_error(
            "write operation failed ("+std::to_string(data->res)+" != "+std::to_string(data->iov.iov_len)+
            "). in-memory state is corrupted. AAAAAAAaaaaaaaaa!!!111"
@ -232,10 +143,53 @@ void blockstore_impl_t::handle_stable_event(ring_data_t *data, blockstore_op_t *
    PRIV(op)->pending_ops--;
    if (PRIV(op)->pending_ops == 0)
    {
-        PRIV(op)->op_state++;
+        // Release used journal sectors
-        if (!continue_stable(op))
+        release_journal_sectors(op);
        // Mark dirty_db entries as stable, acknowledge op completion
        obj_ver_id* v;
        int i;
        for (i = 0, v = (obj_ver_id*)op->buf; i < op->len; i++, v++)
        {
-            submit_queue.push_front(op);
+            // Mark all dirty_db entries up to op->version as stable
            auto dirty_it = dirty_db.find(*v);
            if (dirty_it != dirty_db.end())
            {
                while (1)
                {
                    if (dirty_it->second.state == ST_J_SYNCED)
                    {
                        dirty_it->second.state = ST_J_STABLE;
                    }
                    else if (dirty_it->second.state == ST_D_META_SYNCED)
                    {
                        dirty_it->second.state = ST_D_STABLE;
                    }
                    else if (dirty_it->second.state == ST_DEL_SYNCED)
                    {
                        dirty_it->second.state = ST_DEL_STABLE;
                    }
                    else if (IS_STABLE(dirty_it->second.state))
                    {
                        break;
                    }
                    if (dirty_it == dirty_db.begin())
                    {
                        break;
                    }
                    dirty_it--;
                    if (dirty_it->first.oid != v->oid)
                    {
                        break;
                    }
                }
 #ifdef BLOCKSTORE_DEBUG
                printf("enqueue_flush %lu:%lu v%lu\n", v->oid.inode, v->oid.stripe, v->version);
 #endif
                flusher->enqueue_flush(*v);
            }
        }
        // Acknowledge op
        op->retval = 0;
        FINISH_OP(op);
    }
 }
--- a/blockstore_sync.cpp
+++ b/blockstore_sync.cpp
@ -1,6 +1,3 @@
 // Copyright (c) Vitaliy Filippov, 2019+
 // License: VNPL-1.0 (see README.md for details)
 #include "blockstore_impl.h"
 #define SYNC_HAS_SMALL 1
@ -14,7 +11,7 @@
 int blockstore_impl_t::dequeue_sync(blockstore_op_t *op)
 {
-    if (PRIV(op)->op_state == 0)
+    if (PRIV(op)->sync_state == 0)
    {
        stop_sync_submitted = false;
        PRIV(op)->sync_big_writes.swap(unsynced_big_writes);
@ -24,11 +21,11 @@ int blockstore_impl_t::dequeue_sync(blockstore_op_t *op)
        unsynced_big_writes.clear();
        unsynced_small_writes.clear();
        if (PRIV(op)->sync_big_writes.size() > 0)
-            PRIV(op)->op_state = SYNC_HAS_BIG;
+            PRIV(op)->sync_state = SYNC_HAS_BIG;
        else if (PRIV(op)->sync_small_writes.size() > 0)
-            PRIV(op)->op_state = SYNC_HAS_SMALL;
+            PRIV(op)->sync_state = SYNC_HAS_SMALL;
        else
-            PRIV(op)->op_state = SYNC_DONE;
+            PRIV(op)->sync_state = SYNC_DONE;
        // Always add sync to in_progress_syncs because we clear unsynced_big_writes and unsynced_small_writes
        PRIV(op)->prev_sync_count = in_progress_syncs.size();
        PRIV(op)->in_progress_ptr = in_progress_syncs.insert(in_progress_syncs.end(), op);
@ -41,7 +38,7 @@ int blockstore_impl_t::dequeue_sync(blockstore_op_t *op)
 int blockstore_impl_t::continue_sync(blockstore_op_t *op)
 {
    auto cb = [this, op](ring_data_t *data) { handle_sync_event(data, op); };
-    if (PRIV(op)->op_state == SYNC_HAS_SMALL)
+    if (PRIV(op)->sync_state == SYNC_HAS_SMALL)
    {
        // No big writes, just fsync the journal
        for (; PRIV(op)->sync_small_checked < PRIV(op)->sync_small_writes.size(); PRIV(op)->sync_small_checked++)
@ -57,17 +54,17 @@ int blockstore_impl_t::continue_sync(blockstore_op_t *op)
            // Write out the last journal sector if it happens to be dirty
            BS_SUBMIT_GET_ONLY_SQE(sqe);
            prepare_journal_sector_write(journal, journal.cur_sector, sqe, cb);
-            PRIV(op)->min_flushed_journal_sector = PRIV(op)->max_flushed_journal_sector = 1 + journal.cur_sector;
+            PRIV(op)->min_used_journal_sector = PRIV(op)->max_used_journal_sector = 1 + journal.cur_sector;
            PRIV(op)->pending_ops = 1;
-            PRIV(op)->op_state = SYNC_JOURNAL_WRITE_SENT;
+            PRIV(op)->sync_state = SYNC_JOURNAL_WRITE_SENT;
            return 1;
        }
        else
        {
-            PRIV(op)->op_state = SYNC_JOURNAL_WRITE_DONE;
+            PRIV(op)->sync_state = SYNC_JOURNAL_WRITE_DONE;
        }
    }
-    if (PRIV(op)->op_state == SYNC_HAS_BIG)
+    if (PRIV(op)->sync_state == SYNC_HAS_BIG)
    {
        for (; PRIV(op)->sync_big_checked < PRIV(op)->sync_big_writes.size(); PRIV(op)->sync_big_checked++)
        {
@ -81,20 +78,21 @@ int blockstore_impl_t::continue_sync(blockstore_op_t *op)
        if (!disable_data_fsync)
        {
            BS_SUBMIT_GET_SQE(sqe, data);
-            my_uring_prep_fsync(sqe, data_fd, IORING_FSYNC_DATASYNC);
+            my_uring_prep_fsync(sqe, data_fd_index, IORING_FSYNC_DATASYNC);
            sqe->flags |= IOSQE_FIXED_FILE;
            data->iov = { 0 };
            data->callback = cb;
-            PRIV(op)->min_flushed_journal_sector = PRIV(op)->max_flushed_journal_sector = 0;
+            PRIV(op)->min_used_journal_sector = PRIV(op)->max_used_journal_sector = 0;
            PRIV(op)->pending_ops = 1;
-            PRIV(op)->op_state = SYNC_DATA_SYNC_SENT;
+            PRIV(op)->sync_state = SYNC_DATA_SYNC_SENT;
            return 1;
        }
        else
        {
-            PRIV(op)->op_state = SYNC_DATA_SYNC_DONE;
+            PRIV(op)->sync_state = SYNC_DATA_SYNC_DONE;
        }
    }
-    if (PRIV(op)->op_state == SYNC_DATA_SYNC_DONE)
+    if (PRIV(op)->sync_state == SYNC_DATA_SYNC_DONE)
    {
        for (; PRIV(op)->sync_small_checked < PRIV(op)->sync_small_writes.size(); PRIV(op)->sync_small_checked++)
        {
@ -124,25 +122,19 @@ int blockstore_impl_t::continue_sync(blockstore_op_t *op)
            journal.sector_info[journal.cur_sector].dirty)
        {
            if (cur_sector == -1)
-                PRIV(op)->min_flushed_journal_sector = 1 + journal.cur_sector;
+                PRIV(op)->min_used_journal_sector = 1 + journal.cur_sector;
            cur_sector = journal.cur_sector;
            prepare_journal_sector_write(journal, cur_sector, sqe[s++], cb);
        }
        while (it != PRIV(op)->sync_big_writes.end())
        {
-            journal_entry_big_write *je = (journal_entry_big_write*)prefill_single_journal_entry(
+            journal_entry_big_write *je = (journal_entry_big_write*)
-                journal, (dirty_db[*it].state & BS_ST_INSTANT) ? JE_BIG_WRITE_INSTANT : JE_BIG_WRITE,
+                prefill_single_journal_entry(journal, JE_BIG_WRITE, sizeof(journal_entry_big_write));
                sizeof(journal_entry_big_write)
            );
            dirty_db[*it].journal_sector = journal.sector_info[journal.cur_sector].offset;
            journal.sector_info[journal.cur_sector].dirty = false;
            journal.used_sectors[journal.sector_info[journal.cur_sector].offset]++;
 #ifdef BLOCKSTORE_DEBUG
-            printf(
+            printf("journal offset %lu is used by %lu:%lu v%lu\n", dirty_db[*it].journal_sector, it->oid.inode, it->oid.stripe, it->version);
                "journal offset %08lx is used by %lx:%lx v%lu (%lu refs)\n",
                dirty_db[*it].journal_sector, it->oid.inode, it->oid.stripe, it->version,
                journal.used_sectors[journal.sector_info[journal.cur_sector].offset]
            );
 #endif
            je->oid = it->oid;
            je->version = it->version;
@ -155,36 +147,37 @@ int blockstore_impl_t::continue_sync(blockstore_op_t *op)
            if (cur_sector != journal.cur_sector)
            {
                if (cur_sector == -1)
-                    PRIV(op)->min_flushed_journal_sector = 1 + journal.cur_sector;
+                    PRIV(op)->min_used_journal_sector = 1 + journal.cur_sector;
                cur_sector = journal.cur_sector;
                prepare_journal_sector_write(journal, cur_sector, sqe[s++], cb);
            }
        }
-        PRIV(op)->max_flushed_journal_sector = 1 + journal.cur_sector;
+        PRIV(op)->max_used_journal_sector = 1 + journal.cur_sector;
        PRIV(op)->pending_ops = s;
-        PRIV(op)->op_state = SYNC_JOURNAL_WRITE_SENT;
+        PRIV(op)->sync_state = SYNC_JOURNAL_WRITE_SENT;
        return 1;
    }
-    if (PRIV(op)->op_state == SYNC_JOURNAL_WRITE_DONE)
+    if (PRIV(op)->sync_state == SYNC_JOURNAL_WRITE_DONE)
    {
        if (!disable_journal_fsync)
        {
            BS_SUBMIT_GET_SQE(sqe, data);
-            my_uring_prep_fsync(sqe, journal.fd, IORING_FSYNC_DATASYNC);
+            my_uring_prep_fsync(sqe, journal_fd_index, IORING_FSYNC_DATASYNC);
            sqe->flags |= IOSQE_FIXED_FILE;
            data->iov = { 0 };
            data->callback = cb;
            PRIV(op)->pending_ops = 1;
-            PRIV(op)->op_state = SYNC_JOURNAL_SYNC_SENT;
+            PRIV(op)->sync_state = SYNC_JOURNAL_SYNC_SENT;
            return 1;
        }
        else
        {
-            PRIV(op)->op_state = SYNC_DONE;
+            PRIV(op)->sync_state = SYNC_DONE;
        }
    }
-    if (PRIV(op)->op_state == SYNC_DONE)
+    if (PRIV(op)->sync_state == SYNC_DONE)
    {
-        return ack_sync(op);
+        ack_sync(op);
    }
    return 1;
 }
@ -205,17 +198,17 @@ void blockstore_impl_t::handle_sync_event(ring_data_t *data, blockstore_op_t *op
        // Release used journal sectors
        release_journal_sectors(op);
        // Handle states
-        if (PRIV(op)->op_state == SYNC_DATA_SYNC_SENT)
+        if (PRIV(op)->sync_state == SYNC_DATA_SYNC_SENT)
        {
-            PRIV(op)->op_state = SYNC_DATA_SYNC_DONE;
+            PRIV(op)->sync_state = SYNC_DATA_SYNC_DONE;
        }
-        else if (PRIV(op)->op_state == SYNC_JOURNAL_WRITE_SENT)
+        else if (PRIV(op)->sync_state == SYNC_JOURNAL_WRITE_SENT)
        {
-            PRIV(op)->op_state = SYNC_JOURNAL_WRITE_DONE;
+            PRIV(op)->sync_state = SYNC_JOURNAL_WRITE_DONE;
        }
-        else if (PRIV(op)->op_state == SYNC_JOURNAL_SYNC_SENT)
+        else if (PRIV(op)->sync_state == SYNC_JOURNAL_SYNC_SENT)
        {
-            PRIV(op)->op_state = SYNC_DONE;
+            PRIV(op)->sync_state = SYNC_DONE;
            ack_sync(op);
        }
        else
@ -227,7 +220,7 @@ void blockstore_impl_t::handle_sync_event(ring_data_t *data, blockstore_op_t *op
 int blockstore_impl_t::ack_sync(blockstore_op_t *op)
 {
-    if (PRIV(op)->op_state == SYNC_DONE && PRIV(op)->prev_sync_count == 0)
+    if (PRIV(op)->sync_state == SYNC_DONE && PRIV(op)->prev_sync_count == 0)
    {
        // Remove dependency of subsequent syncs
        auto it = PRIV(op)->in_progress_ptr;
@ -239,14 +232,14 @@ int blockstore_impl_t::ack_sync(blockstore_op_t *op)
        {
            auto & next_sync = *it++;
            PRIV(next_sync)->prev_sync_count -= done_syncs;
-            if (PRIV(next_sync)->prev_sync_count == 0 && PRIV(next_sync)->op_state == SYNC_DONE)
+            if (PRIV(next_sync)->prev_sync_count == 0 && PRIV(next_sync)->sync_state == SYNC_DONE)
            {
                done_syncs++;
                // Acknowledge next_sync
                ack_one_sync(next_sync);
            }
        }
-        return 2;
+        return 1;
    }
    return 0;
 }
@ -257,47 +250,20 @@ void blockstore_impl_t::ack_one_sync(blockstore_op_t *op)
    for (auto it = PRIV(op)->sync_big_writes.begin(); it != PRIV(op)->sync_big_writes.end(); it++)
    {
 #ifdef BLOCKSTORE_DEBUG
-        printf("Ack sync big %lx:%lx v%lu\n", it->oid.inode, it->oid.stripe, it->version);
+        printf("Ack sync big %lu:%lu v%lu\n", it->oid.inode, it->oid.stripe, it->version);
 #endif
        auto & unstab = unstable_writes[it->oid];
        unstab = unstab < it->version ? it->version : unstab;
-        auto dirty_it = dirty_db.find(*it);
+        dirty_db[*it].state = ST_D_META_SYNCED;
        dirty_it->second.state = ((dirty_it->second.state & ~BS_ST_WORKFLOW_MASK) | BS_ST_SYNCED);
        if (dirty_it->second.state & BS_ST_INSTANT)
        {
            mark_stable(dirty_it->first);
        }
        dirty_it++;
        while (dirty_it != dirty_db.end() && dirty_it->first.oid == it->oid)
        {
            if ((dirty_it->second.state & BS_ST_WORKFLOW_MASK) == BS_ST_WAIT_BIG)
            {
                dirty_it->second.state = (dirty_it->second.state & ~BS_ST_WORKFLOW_MASK) | BS_ST_IN_FLIGHT;
            }
            dirty_it++;
        }
    }
    for (auto it = PRIV(op)->sync_small_writes.begin(); it != PRIV(op)->sync_small_writes.end(); it++)
    {
 #ifdef BLOCKSTORE_DEBUG
-        printf("Ack sync small %lx:%lx v%lu\n", it->oid.inode, it->oid.stripe, it->version);
+        printf("Ack sync small %lu:%lu v%lu\n", it->oid.inode, it->oid.stripe, it->version);
 #endif
        auto & unstab = unstable_writes[it->oid];
        unstab = unstab < it->version ? it->version : unstab;
-        if (dirty_db[*it].state == (BS_ST_DELETE | BS_ST_WRITTEN))
+        dirty_db[*it].state = dirty_db[*it].state == ST_DEL_WRITTEN ? ST_DEL_SYNCED : ST_J_SYNCED;
        {
            dirty_db[*it].state = (BS_ST_DELETE | BS_ST_SYNCED);
            // Deletions are treated as immediately stable
            mark_stable(*it);
        }
        else /* (BS_ST_INSTANT?) | BS_ST_SMALL_WRITE | BS_ST_WRITTEN */
        {
            dirty_db[*it].state = (dirty_db[*it].state & ~BS_ST_WORKFLOW_MASK) | BS_ST_SYNCED;
            if (dirty_db[*it].state & BS_ST_INSTANT)
            {
                mark_stable(*it);
            }
        }
    }
    in_progress_syncs.erase(PRIV(op)->in_progress_ptr);
    op->retval = 0;
--- a/blockstore_write.cpp
+++ b/blockstore_write.cpp
@ -1,13 +1,9 @@
 // Copyright (c) Vitaliy Filippov, 2019+
 // License: VNPL-1.0 (see README.md for details)
 #include "blockstore_impl.h"
 bool blockstore_impl_t::enqueue_write(blockstore_op_t *op)
 {
    // Check or assign version number
    bool found = false, deleted = false, is_del = (op->opcode == BS_OP_DELETE);
    bool is_inflight_big = false;
    uint64_t version = 1;
    if (dirty_db.size() > 0)
    {
@ -21,9 +17,6 @@ bool blockstore_impl_t::enqueue_write(blockstore_op_t *op)
            found = true;
            version = dirty_it->first.version + 1;
            deleted = IS_DELETE(dirty_it->second.state);
            is_inflight_big = (dirty_it->second.state & BS_ST_TYPE_MASK) == BS_ST_BIG_WRITE
                ? !IS_SYNCED(dirty_it->second.state)
                : ((dirty_it->second.state & BS_ST_WORKFLOW_MASK) == BS_ST_WAIT_BIG);
        }
    }
    if (!found)
@ -45,7 +38,7 @@ bool blockstore_impl_t::enqueue_write(blockstore_op_t *op)
    else if (op->version < version)
    {
        // Invalid version requested
-        op->retval = -EEXIST;
+        op->retval = -EINVAL;
        return false;
    }
    if (deleted && is_del)
@ -54,36 +47,18 @@ bool blockstore_impl_t::enqueue_write(blockstore_op_t *op)
        op->retval = 0;
        return false;
    }
-    if (is_inflight_big && !is_del && !deleted && op->len < block_size &&
+    // Immediately add the operation into dirty_db, so subsequent reads could see it
        immediate_commit != IMMEDIATE_ALL)
    {
        // Issue an additional sync so that the previous big write can reach the journal
        blockstore_op_t *sync_op = new blockstore_op_t;
        sync_op->opcode = BS_OP_SYNC;
        sync_op->callback = [this, op](blockstore_op_t *sync_op)
        {
            delete sync_op;
        };
        enqueue_op(sync_op);
    }
 #ifdef BLOCKSTORE_DEBUG
-    if (is_del)
+    printf("%s %lu:%lu v%lu\n", is_del ? "Delete" : "Write", op->oid.inode, op->oid.stripe, op->version);
        printf("Delete %lx:%lx v%lu\n", op->oid.inode, op->oid.stripe, op->version);
    else
        printf("Write %lx:%lx v%lu offset=%u len=%u\n", op->oid.inode, op->oid.stripe, op->version, op->offset, op->len);
 #endif
    // No strict need to add it into dirty_db here, it's just left
    // from the previous implementation where reads waited for writes
    dirty_db.emplace((obj_ver_id){
        .oid = op->oid,
        .version = op->version,
    }, (dirty_entry){
        .state = (uint32_t)(
            is_del
-                ? (BS_ST_DELETE | BS_ST_IN_FLIGHT)
+                ? ST_DEL_IN_FLIGHT
-                : (op->opcode == BS_OP_WRITE_STABLE ? BS_ST_INSTANT : 0) | (op->len == block_size || deleted
+                : (op->len == block_size || deleted ? ST_D_IN_FLIGHT : ST_J_IN_FLIGHT)
                    ? (BS_ST_BIG_WRITE | BS_ST_IN_FLIGHT)
                    : (is_inflight_big ? (BS_ST_SMALL_WRITE | BS_ST_WAIT_BIG) : (BS_ST_SMALL_WRITE | BS_ST_IN_FLIGHT)))
        ),
        .flags = 0,
        .location = 0,
@ -97,21 +72,11 @@ bool blockstore_impl_t::enqueue_write(blockstore_op_t *op)
 // First step of the write algorithm: dequeue operation and submit initial write(s)
 int blockstore_impl_t::dequeue_write(blockstore_op_t *op)
 {
    if (PRIV(op)->op_state)
    {
        return continue_write(op);
    }
    auto dirty_it = dirty_db.find((obj_ver_id){
        .oid = op->oid,
        .version = op->version,
    });
-    assert(dirty_it != dirty_db.end());
+    if (dirty_it->second.state == ST_D_IN_FLIGHT)
    if ((dirty_it->second.state & BS_ST_WORKFLOW_MASK) == BS_ST_WAIT_BIG)
    {
        // Don't dequeue
        return 0;
    }
    else if ((dirty_it->second.state & BS_ST_TYPE_MASK) == BS_ST_BIG_WRITE)
    {
        blockstore_journal_check_t space_check(this);
        if (!space_check.check_available(op, unsynced_big_writes.size() + 1, sizeof(journal_entry_big_write), JOURNAL_STABILIZE_RESERVATION))
@ -135,7 +100,7 @@ int blockstore_impl_t::dequeue_write(blockstore_op_t *op)
        }
        BS_SUBMIT_GET_SQE(sqe, data);
        dirty_it->second.location = loc << block_order;
-        dirty_it->second.state = (dirty_it->second.state & ~BS_ST_WORKFLOW_MASK) | BS_ST_SUBMITTED;
+        dirty_it->second.state = ST_D_SUBMITTED;
 #ifdef BLOCKSTORE_DEBUG
        printf("Allocate block %lu\n", loc);
 #endif
@ -157,25 +122,18 @@ int blockstore_impl_t::dequeue_write(blockstore_op_t *op)
        data->iov.iov_len = op->len + stripe_offset + stripe_end; // to check it in the callback
        data->callback = [this, op](ring_data_t *data) { handle_write_event(data, op); };
        my_uring_prep_writev(
-            sqe, data_fd, PRIV(op)->iov_zerofill, vcnt, data_offset + (loc << block_order) + op->offset - stripe_offset
+            sqe, data_fd_index, PRIV(op)->iov_zerofill, vcnt, data_offset + (loc << block_order) + op->offset - stripe_offset
        );
        sqe->flags |= IOSQE_FIXED_FILE;
        PRIV(op)->pending_ops = 1;
-        PRIV(op)->min_flushed_journal_sector = PRIV(op)->max_flushed_journal_sector = 0;
+        PRIV(op)->min_used_journal_sector = PRIV(op)->max_used_journal_sector = 0;
-        if (immediate_commit != IMMEDIATE_ALL)
+        // Remember big write as unsynced
-        {
+        unsynced_big_writes.push_back((obj_ver_id){
-            // Remember big write as unsynced
+            .oid = op->oid,
-            unsynced_big_writes.push_back((obj_ver_id){
+            .version = op->version,
-                .oid = op->oid,
+        });
                .version = op->version,
            });
            PRIV(op)->op_state = 3;
        }
        else
        {
            PRIV(op)->op_state = 1;
        }
    }
-    else /* if ((dirty_it->second.state & BS_ST_TYPE_MASK) == BS_ST_SMALL_WRITE) */
+    else
    {
        // Small (journaled) write
        // First check if the journal has sufficient space
@ -187,11 +145,10 @@ int blockstore_impl_t::dequeue_write(blockstore_op_t *op)
        }
        // There is sufficient space. Get SQE(s)
        struct io_uring_sqe *sqe1 = NULL;
-        if (immediate_commit != IMMEDIATE_NONE ||
+        if ((journal_block_size - journal.in_sector_pos) < sizeof(journal_entry_small_write) &&
            (journal_block_size - journal.in_sector_pos) < sizeof(journal_entry_small_write) &&
            journal.sector_info[journal.cur_sector].dirty)
        {
-            // Write current journal sector only if it's dirty and full, or in the immediate_commit mode
+            // Write current journal sector only if it's dirty and full
            BS_SUBMIT_GET_SQE_DECL(sqe1);
        }
        struct io_uring_sqe *sqe2 = NULL;
@ -201,32 +158,24 @@ int blockstore_impl_t::dequeue_write(blockstore_op_t *op)
        }
        // Got SQEs. Prepare previous journal sector write if required
        auto cb = [this, op](ring_data_t *data) { handle_write_event(data, op); };
-        if (immediate_commit == IMMEDIATE_NONE)
+        if (sqe1)
        {
-            if (sqe1)
+            prepare_journal_sector_write(journal, journal.cur_sector, sqe1, cb);
-            {
+            // FIXME rename to min/max _flushing
-                prepare_journal_sector_write(journal, journal.cur_sector, sqe1, cb);
+            PRIV(op)->min_used_journal_sector = PRIV(op)->max_used_journal_sector = 1 + journal.cur_sector;
-                PRIV(op)->min_flushed_journal_sector = PRIV(op)->max_flushed_journal_sector = 1 + journal.cur_sector;
+            PRIV(op)->pending_ops++;
-                PRIV(op)->pending_ops++;
+        }
-            }
+        else
-            else
+        {
-            {
+            PRIV(op)->min_used_journal_sector = PRIV(op)->max_used_journal_sector = 0;
                PRIV(op)->min_flushed_journal_sector = PRIV(op)->max_flushed_journal_sector = 0;
            }
        }
        // Then pre-fill journal entry
-        journal_entry_small_write *je = (journal_entry_small_write*)prefill_single_journal_entry(
+        journal_entry_small_write *je = (journal_entry_small_write*)
-            journal, op->opcode == BS_OP_WRITE_STABLE ? JE_SMALL_WRITE_INSTANT : JE_SMALL_WRITE,
+            prefill_single_journal_entry(journal, JE_SMALL_WRITE, sizeof(journal_entry_small_write));
            sizeof(journal_entry_small_write)
        );
        dirty_it->second.journal_sector = journal.sector_info[journal.cur_sector].offset;
        journal.used_sectors[journal.sector_info[journal.cur_sector].offset]++;
 #ifdef BLOCKSTORE_DEBUG
-        printf(
+        printf("journal offset %lu is used by %lu:%lu v%lu\n", dirty_it->second.journal_sector, dirty_it->first.oid.inode, dirty_it->first.oid.stripe, dirty_it->first.version);
            "journal offset %08lx is used by %lx:%lx v%lu (%lu refs)\n",
            dirty_it->second.journal_sector, dirty_it->first.oid.inode, dirty_it->first.oid.stripe, dirty_it->first.version,
            journal.used_sectors[journal.sector_info[journal.cur_sector].offset]
        );
 #endif
        // Figure out where data will be
        journal.next_free = (journal.next_free + op->len) <= journal.len ? journal.next_free : journal_block_size;
@ -238,12 +187,6 @@ int blockstore_impl_t::dequeue_write(blockstore_op_t *op)
        je->crc32_data = crc32c(0, op->buf, op->len);
        je->crc32 = je_crc32((journal_entry*)je);
        journal.crc32_last = je->crc32;
        if (immediate_commit != IMMEDIATE_NONE)
        {
            prepare_journal_sector_write(journal, journal.cur_sector, sqe1, cb);
            PRIV(op)->min_flushed_journal_sector = PRIV(op)->max_flushed_journal_sector = 1 + journal.cur_sector;
            PRIV(op)->pending_ops++;
        }
        if (op->len > 0)
        {
            // Prepare journal data write
@ -256,8 +199,9 @@ int blockstore_impl_t::dequeue_write(blockstore_op_t *op)
            data2->iov = (struct iovec){ op->buf, op->len };
            data2->callback = cb;
            my_uring_prep_writev(
-                sqe2, journal.fd, &data2->iov, 1, journal.offset + journal.next_free
+                sqe2, journal_fd_index, &data2->iov, 1, journal.offset + journal.next_free
            );
            sqe2->flags |= IOSQE_FIXED_FILE;
            PRIV(op)->pending_ops++;
        }
        else
@ -265,119 +209,22 @@ int blockstore_impl_t::dequeue_write(blockstore_op_t *op)
            // Zero-length overwrite. Allowed to bump object version in EC placement groups without actually writing data
        }
        dirty_it->second.location = journal.next_free;
-        dirty_it->second.state = (dirty_it->second.state & ~BS_ST_WORKFLOW_MASK) | BS_ST_SUBMITTED;
+        dirty_it->second.state = ST_J_SUBMITTED;
        journal.next_free += op->len;
        if (journal.next_free >= journal.len)
        {
            journal.next_free = journal_block_size;
        }
-        if (immediate_commit == IMMEDIATE_NONE)
+        // Remember small write as unsynced
-        {
+        unsynced_small_writes.push_back((obj_ver_id){
-            // Remember small write as unsynced
+            .oid = op->oid,
-            unsynced_small_writes.push_back((obj_ver_id){
+            .version = op->version,
-                .oid = op->oid,
+        });
                .version = op->version,
            });
        }
        if (!PRIV(op)->pending_ops)
        {
-            PRIV(op)->op_state = 4;
+            ack_write(op);
            continue_write(op);
        }
        else
        {
            PRIV(op)->op_state = 3;
        }
    }
    inflight_writes++;
    return 1;
 }
 int blockstore_impl_t::continue_write(blockstore_op_t *op)
 {
    io_uring_sqe *sqe = NULL;
    journal_entry_big_write *je;
    auto dirty_it = dirty_db.find((obj_ver_id){
        .oid = op->oid,
        .version = op->version,
    });
    assert(dirty_it != dirty_db.end());
    if (PRIV(op)->op_state == 2)
        goto resume_2;
    else if (PRIV(op)->op_state == 4)
        goto resume_4;
    else
        return 1;
 resume_2:
    // Only for the immediate_commit mode: prepare and submit big_write journal entry
    sqe = get_sqe();
    if (!sqe)
    {
        return 0;
    }
    je = (journal_entry_big_write*)prefill_single_journal_entry(
        journal, op->opcode == BS_OP_WRITE_STABLE ? JE_BIG_WRITE_INSTANT : JE_BIG_WRITE,
        sizeof(journal_entry_big_write)
    );
    dirty_it->second.journal_sector = journal.sector_info[journal.cur_sector].offset;
    journal.sector_info[journal.cur_sector].dirty = false;
    journal.used_sectors[journal.sector_info[journal.cur_sector].offset]++;
 #ifdef BLOCKSTORE_DEBUG
    printf(
        "journal offset %08lx is used by %lx:%lx v%lu (%lu refs)\n",
        journal.sector_info[journal.cur_sector].offset, op->oid.inode, op->oid.stripe, op->version,
        journal.used_sectors[journal.sector_info[journal.cur_sector].offset]
    );
 #endif
    je->oid = op->oid;
    je->version = op->version;
    je->offset = op->offset;
    je->len = op->len;
    je->location = dirty_it->second.location;
    je->crc32 = je_crc32((journal_entry*)je);
    journal.crc32_last = je->crc32;
    prepare_journal_sector_write(journal, journal.cur_sector, sqe,
        [this, op](ring_data_t *data) { handle_write_event(data, op); });
    PRIV(op)->min_flushed_journal_sector = PRIV(op)->max_flushed_journal_sector = 1 + journal.cur_sector;
    PRIV(op)->pending_ops = 1;
    PRIV(op)->op_state = 3;
    return 1;
 resume_4:
    // Switch object state
 #ifdef BLOCKSTORE_DEBUG
    printf("Ack write %lx:%lx v%lu = %d\n", op->oid.inode, op->oid.stripe, op->version, dirty_it->second.state);
 #endif
    bool imm = (dirty_it->second.state & BS_ST_TYPE_MASK) == BS_ST_BIG_WRITE
        ? (immediate_commit == IMMEDIATE_ALL)
        : (immediate_commit != IMMEDIATE_NONE);
    if (imm)
    {
        auto & unstab = unstable_writes[op->oid];
        unstab = unstab < op->version ? op->version : unstab;
    }
    dirty_it->second.state = (dirty_it->second.state & ~BS_ST_WORKFLOW_MASK)
        | (imm ? BS_ST_SYNCED : BS_ST_WRITTEN);
    if (imm && ((dirty_it->second.state & BS_ST_TYPE_MASK) == BS_ST_DELETE || (dirty_it->second.state & BS_ST_INSTANT)))
    {
        // Deletions are treated as immediately stable
        mark_stable(dirty_it->first);
    }
    if (immediate_commit == IMMEDIATE_ALL)
    {
        dirty_it++;
        while (dirty_it != dirty_db.end() && dirty_it->first.oid == op->oid)
        {
            if ((dirty_it->second.state & BS_ST_WORKFLOW_MASK) == BS_ST_WAIT_BIG)
            {
                dirty_it->second.state = (dirty_it->second.state & ~BS_ST_WORKFLOW_MASK) | BS_ST_IN_FLIGHT;
            }
            dirty_it++;
        }
    }
    inflight_writes--;
    // Acknowledge write
    op->retval = op->len;
    FINISH_OP(op);
    return 1;
 }
@ -386,7 +233,6 @@ void blockstore_impl_t::handle_write_event(ring_data_t *data, blockstore_op_t *o
    live = true;
    if (data->res != data->iov.iov_len)
    {
        inflight_writes--;
        // FIXME: our state becomes corrupted after a write error. maybe do something better than just die
        throw std::runtime_error(
            "write operation failed ("+std::to_string(data->res)+" != "+std::to_string(data->iov.iov_len)+
@ -397,118 +243,88 @@ void blockstore_impl_t::handle_write_event(ring_data_t *data, blockstore_op_t *o
    if (PRIV(op)->pending_ops == 0)
    {
        release_journal_sectors(op);
-        PRIV(op)->op_state++;
+        ack_write(op);
        if (!continue_write(op))
        {
            submit_queue.push_front(op);
        }
    }
 }
 void blockstore_impl_t::release_journal_sectors(blockstore_op_t *op)
 {
-    // Release flushed journal sectors
+    // Release used journal sectors
-    if (PRIV(op)->min_flushed_journal_sector > 0 &&
+    if (PRIV(op)->min_used_journal_sector > 0 &&
-        PRIV(op)->max_flushed_journal_sector > 0)
+        PRIV(op)->max_used_journal_sector > 0)
    {
-        uint64_t s = PRIV(op)->min_flushed_journal_sector;
+        uint64_t s = PRIV(op)->min_used_journal_sector;
        while (1)
        {
            journal.sector_info[s-1].usage_count--;
-            if (s != (1+journal.cur_sector) && journal.sector_info[s-1].usage_count == 0)
+            if (s == PRIV(op)->max_used_journal_sector)
            {
                // We know for sure that we won't write into this sector anymore
                uint64_t new_ds = journal.sector_info[s-1].offset + journal.block_size;
                if (new_ds >= journal.len)
                {
                    new_ds = journal.block_size;
                }
                if ((journal.dirty_start + (journal.dirty_start >= journal.used_start ? 0 : journal.len)) <
                    (new_ds + (new_ds >= journal.used_start ? 0 : journal.len)))
                {
                    journal.dirty_start = new_ds;
                }
            }
            if (s == PRIV(op)->max_flushed_journal_sector)
                break;
            s = 1 + s % journal.sector_count;
        }
-        PRIV(op)->min_flushed_journal_sector = PRIV(op)->max_flushed_journal_sector = 0;
+        PRIV(op)->min_used_journal_sector = PRIV(op)->max_used_journal_sector = 0;
    }
 }
 void blockstore_impl_t::ack_write(blockstore_op_t *op)
 {
    // Switch object state
    auto & dirty_entry = dirty_db[(obj_ver_id){
        .oid = op->oid,
        .version = op->version,
    }];
 #ifdef BLOCKSTORE_DEBUG
    printf("Ack write %lu:%lu v%lu = %d\n", op->oid.inode, op->oid.stripe, op->version, dirty_entry.state);
 #endif
    if (dirty_entry.state == ST_J_SUBMITTED)
    {
        dirty_entry.state = ST_J_WRITTEN;
    }
    else if (dirty_entry.state == ST_D_SUBMITTED)
    {
        dirty_entry.state = ST_D_WRITTEN;
    }
    else if (dirty_entry.state == ST_DEL_SUBMITTED)
    {
        dirty_entry.state = ST_DEL_WRITTEN;
    }
    // Acknowledge write without sync
    op->retval = op->len;
    FINISH_OP(op);
 }
 int blockstore_impl_t::dequeue_del(blockstore_op_t *op)
 {
    auto dirty_it = dirty_db.find((obj_ver_id){
        .oid = op->oid,
        .version = op->version,
    });
    assert(dirty_it != dirty_db.end());
    blockstore_journal_check_t space_check(this);
    if (!space_check.check_available(op, 1, sizeof(journal_entry_del), 0))
    {
        return 0;
    }
-    io_uring_sqe *sqe = NULL;
+    BS_SUBMIT_GET_ONLY_SQE(sqe);
    if (immediate_commit != IMMEDIATE_NONE ||
        (journal_block_size - journal.in_sector_pos) < sizeof(journal_entry_del) &&
        journal.sector_info[journal.cur_sector].dirty)
    {
        // Write current journal sector only if it's dirty and full, or in the immediate_commit mode
        BS_SUBMIT_GET_SQE_DECL(sqe);
    }
    auto cb = [this, op](ring_data_t *data) { handle_write_event(data, op); };
    // Prepare journal sector write
-    if (immediate_commit == IMMEDIATE_NONE)
+    journal_entry_del *je = (journal_entry_del*)
-    {
+        prefill_single_journal_entry(journal, JE_DELETE, sizeof(struct journal_entry_del));
        if (sqe)
        {
            prepare_journal_sector_write(journal, journal.cur_sector, sqe, cb);
            PRIV(op)->min_flushed_journal_sector = PRIV(op)->max_flushed_journal_sector = 1 + journal.cur_sector;
            PRIV(op)->pending_ops++;
        }
        else
        {
            PRIV(op)->min_flushed_journal_sector = PRIV(op)->max_flushed_journal_sector = 0;
        }
    }
    // Pre-fill journal entry
    journal_entry_del *je = (journal_entry_del*)prefill_single_journal_entry(
        journal, JE_DELETE, sizeof(struct journal_entry_del)
    );
    dirty_it->second.journal_sector = journal.sector_info[journal.cur_sector].offset;
    journal.used_sectors[journal.sector_info[journal.cur_sector].offset]++;
 #ifdef BLOCKSTORE_DEBUG
-    printf(
+    printf("journal offset %lu is used by %lu:%lu v%lu\n", dirty_it->second.journal_sector, dirty_it->first.oid.inode, dirty_it->first.oid.stripe, dirty_it->first.version);
        "journal offset %08lx is used by %lx:%lx v%lu (%lu refs)\n",
        dirty_it->second.journal_sector, dirty_it->first.oid.inode, dirty_it->first.oid.stripe, dirty_it->first.version,
        journal.used_sectors[journal.sector_info[journal.cur_sector].offset]
    );
 #endif
    je->oid = op->oid;
    je->version = op->version;
    je->crc32 = je_crc32((journal_entry*)je);
    journal.crc32_last = je->crc32;
-    dirty_it->second.state = BS_ST_DELETE | BS_ST_SUBMITTED;
+    auto cb = [this, op](ring_data_t *data) { handle_write_event(data, op); };
-    if (immediate_commit != IMMEDIATE_NONE)
+    prepare_journal_sector_write(journal, journal.cur_sector, sqe, cb);
-    {
+    PRIV(op)->min_used_journal_sector = PRIV(op)->max_used_journal_sector = 1 + journal.cur_sector;
-        prepare_journal_sector_write(journal, journal.cur_sector, sqe, cb);
+    PRIV(op)->pending_ops = 1;
-        PRIV(op)->min_flushed_journal_sector = PRIV(op)->max_flushed_journal_sector = 1 + journal.cur_sector;
+    dirty_it->second.state = ST_DEL_SUBMITTED;
-        PRIV(op)->pending_ops++;
+    // Remember small write as unsynced
-        // Remember small write as unsynced
+    unsynced_small_writes.push_back((obj_ver_id){
-        unsynced_small_writes.push_back((obj_ver_id){
+        .oid = op->oid,
-            .oid = op->oid,
+        .version = op->version,
-            .version = op->version,
+    });
        });
    }
    if (!PRIV(op)->pending_ops)
    {
        PRIV(op)->op_state = 4;
        continue_write(op);
    }
    else
    {
        PRIV(op)->op_state = 3;
    }
    return 1;
 }
--- a/cluster_client.cpp
+++ b/cluster_client.cpp
@ -1,745 +0,0 @@
 // Copyright (c) Vitaliy Filippov, 2019+
 // License: VNPL-1.0 or GNU GPL-2.0+ (see README.md for details)
 #include "cluster_client.h"
 cluster_client_t::cluster_client_t(ring_loop_t *ringloop, timerfd_manager_t *tfd, json11::Json & config)
 {
    this->ringloop = ringloop;
    this->tfd = tfd;
    msgr.osd_num = 0;
    msgr.tfd = tfd;
    msgr.ringloop = ringloop;
    msgr.repeer_pgs = [this](osd_num_t peer_osd)
    {
        if (msgr.osd_peer_fds.find(peer_osd) != msgr.osd_peer_fds.end())
        {
            // peer_osd just connected
            continue_ops();
        }
        else if (unsynced_writes.size())
        {
            // peer_osd just dropped connection
            for (auto op: syncing_writes)
            {
                for (auto & part: op->parts)
                {
                    if (part.osd_num == peer_osd && part.done)
                    {
                        // repeat this operation
                        part.osd_num = 0;
                        part.done = false;
                        assert(!part.sent);
                        op->done_count--;
                    }
                }
            }
            for (auto op: unsynced_writes)
            {
                for (auto & part: op->parts)
                {
                    if (part.osd_num == peer_osd && part.done)
                    {
                        // repeat this operation
                        part.osd_num = 0;
                        part.done = false;
                        assert(!part.sent);
                        op->done_count--;
                    }
                }
                if (op->done_count < op->parts.size())
                {
                    cur_ops.insert(op);
                }
            }
            continue_ops();
        }
    };
    msgr.exec_op = [this](osd_op_t *op)
    {
        // Garbage in
        printf("Incoming garbage from peer %d\n", op->peer_fd);
        msgr.stop_client(op->peer_fd);
        delete op;
    };
    msgr.use_sync_send_recv = config["use_sync_send_recv"].bool_value() ||
        config["use_sync_send_recv"].uint64_value();
    st_cli.tfd = tfd;
    st_cli.on_load_config_hook = [this](json11::Json::object & cfg) { on_load_config_hook(cfg); };
    st_cli.on_change_osd_state_hook = [this](uint64_t peer_osd) { on_change_osd_state_hook(peer_osd); };
    st_cli.on_change_hook = [this](json11::Json::object & changes) { on_change_hook(changes); };
    st_cli.on_load_pgs_hook = [this](bool success) { on_load_pgs_hook(success); };
    log_level = config["log_level"].int64_value();
    st_cli.parse_config(config);
    st_cli.load_global_config();
    if (ringloop)
    {
        consumer.loop = [this]()
        {
            msgr.read_requests();
            msgr.send_replies();
            this->ringloop->submit();
        };
        ringloop->register_consumer(&consumer);
    }
 }
 cluster_client_t::~cluster_client_t()
 {
    if (ringloop)
    {
        ringloop->unregister_consumer(&consumer);
    }
 }
 void cluster_client_t::stop()
 {
    while (msgr.clients.size() > 0)
    {
        msgr.stop_client(msgr.clients.begin()->first);
    }
 }
 void cluster_client_t::continue_ops(bool up_retry)
 {
    for (auto op_it = cur_ops.begin(); op_it != cur_ops.end(); )
    {
        if ((*op_it)->up_wait)
        {
            if (up_retry)
            {
                (*op_it)->up_wait = false;
                continue_rw(*op_it++);
            }
            else
                op_it++;
        }
        else
            continue_rw(*op_it++);
    }
 }
 static uint32_t is_power_of_two(uint64_t value)
 {
    uint32_t l = 0;
    while (value > 1)
    {
        if (value & 1)
        {
            return 64;
        }
        value = value >> 1;
        l++;
    }
    return l;
 }
 void cluster_client_t::on_load_config_hook(json11::Json::object & config)
 {
    bs_block_size = config["block_size"].uint64_value();
    bs_disk_alignment = config["disk_alignment"].uint64_value();
    bs_bitmap_granularity = config["bitmap_granularity"].uint64_value();
    if (!bs_block_size)
    {
        bs_block_size = DEFAULT_BLOCK_SIZE;
    }
    if (!bs_disk_alignment)
    {
        bs_disk_alignment = DEFAULT_DISK_ALIGNMENT;
    }
    if (!bs_bitmap_granularity)
    {
        bs_bitmap_granularity = DEFAULT_BITMAP_GRANULARITY;
    }
    uint32_t block_order;
    if ((block_order = is_power_of_two(bs_block_size)) >= 64 || bs_block_size < MIN_BLOCK_SIZE || bs_block_size >= MAX_BLOCK_SIZE)
    {
        throw std::runtime_error("Bad block size");
    }
    if (config["immediate_commit"] == "all")
    {
        // Cluster-wide immediate_commit mode
        immediate_commit = true;
    }
    else if (config.find("client_dirty_limit") != config.end())
    {
        client_dirty_limit = config["client_dirty_limit"].uint64_value();
    }
    if (!client_dirty_limit)
    {
        client_dirty_limit = DEFAULT_CLIENT_DIRTY_LIMIT;
    }
    up_wait_retry_interval = config["up_wait_retry_interval"].uint64_value();
    if (!up_wait_retry_interval)
    {
        up_wait_retry_interval = 500;
    }
    else if (up_wait_retry_interval < 50)
    {
        up_wait_retry_interval = 50;
    }
    msgr.peer_connect_interval = config["peer_connect_interval"].uint64_value();
    if (!msgr.peer_connect_interval)
    {
        msgr.peer_connect_interval = DEFAULT_PEER_CONNECT_INTERVAL;
    }
    msgr.peer_connect_timeout = config["peer_connect_timeout"].uint64_value();
    if (!msgr.peer_connect_timeout)
    {
        msgr.peer_connect_timeout = DEFAULT_PEER_CONNECT_TIMEOUT;
    }
    st_cli.start_etcd_watcher();
    st_cli.load_pgs();
 }
 void cluster_client_t::on_load_pgs_hook(bool success)
 {
    for (auto pool_item: st_cli.pool_config)
    {
        pg_counts[pool_item.first] = pool_item.second.real_pg_count;
    }
    for (auto op: offline_ops)
    {
        execute(op);
    }
    offline_ops.clear();
    continue_ops();
 }
 void cluster_client_t::on_change_hook(json11::Json::object & changes)
 {
    for (auto pool_item: st_cli.pool_config)
    {
        if (pg_counts[pool_item.first] != pool_item.second.real_pg_count)
        {
            // At this point, all pool operations should have been suspended
            // And now they have to be resliced!
            for (auto op: cur_ops)
            {
                if (INODE_POOL(op->inode) == pool_item.first)
                {
                    op->needs_reslice = true;
                }
            }
            for (auto op: unsynced_writes)
            {
                if (INODE_POOL(op->inode) == pool_item.first)
                {
                    op->needs_reslice = true;
                }
            }
            for (auto op: syncing_writes)
            {
                if (INODE_POOL(op->inode) == pool_item.first)
                {
                    op->needs_reslice = true;
                }
            }
            pg_counts[pool_item.first] = pool_item.second.real_pg_count;
        }
    }
    continue_ops();
 }
 void cluster_client_t::on_change_osd_state_hook(uint64_t peer_osd)
 {
    if (msgr.wanted_peers.find(peer_osd) != msgr.wanted_peers.end())
    {
        msgr.connect_peer(peer_osd, st_cli.peer_states[peer_osd]);
    }
 }
 /**
 * How writes are synced when immediate_commit is false
 *
 * 1) accept up to <client_dirty_limit> write operations for execution,
 *    queue all subsequent writes into <next_writes>
 * 2) accept exactly one SYNC, queue all subsequent SYNCs into <next_writes>, too
 * 3) "continue" all accepted writes
 *
 * "Continue" WRITE:
 * 1) if the operation is not a copy yet - copy it (required for replay)
 * 2) if the operation is not sliced yet - slice it
 * 3) if the operation doesn't require reslice - try to connect & send all remaining parts
 * 4) if any of them fail due to disconnected peers or PGs not up, repeat after reconnecting or small timeout
 * 5) if any of them fail due to other errors, fail the operation and forget it from the current "unsynced batch"
 * 6) if PG count changes before all parts are done, wait for all in-progress parts to finish,
 *    throw all results away, reslice and resubmit op
 * 7) when all parts are done, try to "continue" the current SYNC
 * 8) if the operation succeeds, but then some OSDs drop their connections, repeat
 *    parts from the current "unsynced batch" previously sent to those OSDs in any order
 *
 * "Continue" current SYNC:
 * 1) take all unsynced operations from the current batch
 * 2) check if all affected OSDs are still alive
 * 3) if yes, send all SYNCs. otherwise, leave current SYNC as is.
 * 4) if any of them fail due to disconnected peers, repeat SYNC after repeating all writes
 * 5) if any of them fail due to other errors, fail the SYNC operation
 */
 void cluster_client_t::execute(cluster_op_t *op)
 {
    if (!bs_disk_alignment)
    {
        // We're offline
        offline_ops.push_back(op);
        return;
    }
    op->retval = 0;
    if (op->opcode != OSD_OP_SYNC && op->opcode != OSD_OP_READ && op->opcode != OSD_OP_WRITE ||
        (op->opcode == OSD_OP_READ || op->opcode == OSD_OP_WRITE) && (!op->inode || !op->len ||
        op->offset % bs_disk_alignment || op->len % bs_disk_alignment))
    {
        op->retval = -EINVAL;
        std::function<void(cluster_op_t*)>(op->callback)(op);
        return;
    }
    if (op->opcode == OSD_OP_SYNC)
    {
        execute_sync(op);
        return;
    }
    if (op->opcode == OSD_OP_WRITE && !immediate_commit)
    {
        if (next_writes.size() > 0)
        {
            assert(cur_sync);
            next_writes.push_back(op);
            return;
        }
        if (queued_bytes >= client_dirty_limit)
        {
            // Push an extra SYNC operation to flush previous writes
            next_writes.push_back(op);
            cluster_op_t *sync_op = new cluster_op_t;
            sync_op->is_internal = true;
            sync_op->opcode = OSD_OP_SYNC;
            sync_op->callback = [](cluster_op_t* sync_op) {};
            execute_sync(sync_op);
            return;
        }
        queued_bytes += op->len;
    }
    cur_ops.insert(op);
    continue_rw(op);
 }
 void cluster_client_t::continue_rw(cluster_op_t *op)
 {
    pool_id_t pool_id = INODE_POOL(op->inode);
    if (!pool_id)
    {
        op->retval = -EINVAL;
        std::function<void(cluster_op_t*)>(op->callback)(op);
        return;
    }
    if (st_cli.pool_config.find(pool_id) == st_cli.pool_config.end() ||
        st_cli.pool_config[pool_id].real_pg_count == 0)
    {
        // Postpone operations to unknown pools
        return;
    }
    if (op->opcode == OSD_OP_WRITE && !immediate_commit && !op->is_internal)
    {
        // Save operation for replay when PG goes out of sync
        // (primary OSD drops our connection in this case)
        cluster_op_t *op_copy = new cluster_op_t();
        op_copy->is_internal = true;
        op_copy->orig_op = op;
        op_copy->opcode = op->opcode;
        op_copy->inode = op->inode;
        op_copy->offset = op->offset;
        op_copy->len = op->len;
        op_copy->buf = malloc_or_die(op->len);
        op_copy->iov.push_back(op_copy->buf, op->len);
        op_copy->callback = [](cluster_op_t* op_copy)
        {
            if (op_copy->orig_op)
            {
                // Acknowledge write and forget the original pointer
                op_copy->orig_op->retval = op_copy->retval;
                std::function<void(cluster_op_t*)>(op_copy->orig_op->callback)(op_copy->orig_op);
                op_copy->orig_op = NULL;
            }
        };
        void *cur_buf = op_copy->buf;
        for (int i = 0; i < op->iov.count; i++)
        {
            memcpy(cur_buf, op->iov.buf[i].iov_base, op->iov.buf[i].iov_len);
            cur_buf += op->iov.buf[i].iov_len;
        }
        unsynced_writes.push_back(op_copy);
        cur_ops.erase(op);
        cur_ops.insert(op_copy);
        op = op_copy;
    }
    if (!op->parts.size())
    {
        // Slice the operation into parts
        slice_rw(op);
    }
    if (!op->needs_reslice)
    {
        // Send unsent parts, if they're not subject to change
        for (auto & op_part: op->parts)
        {
            if (!op_part.sent && !op_part.done)
            {
                try_send(op, &op_part);
            }
        }
    }
    if (!op->sent_count)
    {
        if (op->done_count >= op->parts.size())
        {
            // Finished successfully
            // Even if the PG count has changed in meanwhile we treat it as success
            // because if some operations were invalid for the new PG count we'd get errors
            cur_ops.erase(op);
            op->retval = op->len;
            std::function<void(cluster_op_t*)>(op->callback)(op);
            continue_sync();
            return;
        }
        else if (op->retval != 0 && op->retval != -EPIPE)
        {
            // Fatal error (not -EPIPE)
            cur_ops.erase(op);
            if (!immediate_commit && op->opcode == OSD_OP_WRITE)
            {
                for (int i = 0; i < unsynced_writes.size(); i++)
                {
                    if (unsynced_writes[i] == op)
                    {
                        unsynced_writes.erase(unsynced_writes.begin()+i, unsynced_writes.begin()+i+1);
                        break;
                    }
                }
            }
            bool del = op->is_internal;
            std::function<void(cluster_op_t*)>(op->callback)(op);
            if (del)
            {
                if (op->buf)
                    free(op->buf);
                delete op;
            }
            continue_sync();
            return;
        }
        else
        {
            // -EPIPE or no error - clear the error
            op->retval = 0;
            if (op->needs_reslice)
            {
                op->parts.clear();
                op->done_count = 0;
                op->needs_reslice = false;
                continue_rw(op);
            }
        }
    }
 }
 void cluster_client_t::slice_rw(cluster_op_t *op)
 {
    // Slice the request into individual object stripe requests
    // Primary OSDs still operate individual stripes, but their size is multiplied by PG minsize in case of EC
    auto & pool_cfg = st_cli.pool_config[INODE_POOL(op->inode)];
    uint64_t pg_block_size = bs_block_size * (
        pool_cfg.scheme == POOL_SCHEME_REPLICATED ? 1 : pool_cfg.pg_minsize
    );
    uint64_t first_stripe = (op->offset / pg_block_size) * pg_block_size;
    uint64_t last_stripe = ((op->offset + op->len + pg_block_size - 1) / pg_block_size - 1) * pg_block_size;
    op->retval = 0;
    op->parts.resize((last_stripe - first_stripe) / pg_block_size + 1);
    int iov_idx = 0;
    size_t iov_pos = 0;
    int i = 0;
    for (uint64_t stripe = first_stripe; stripe <= last_stripe; stripe += pg_block_size)
    {
        pg_num_t pg_num = (op->inode + stripe/pool_cfg.pg_stripe_size) % pool_cfg.real_pg_count + 1;
        uint64_t begin = (op->offset < stripe ? stripe : op->offset);
        uint64_t end = (op->offset + op->len) > (stripe + pg_block_size)
            ? (stripe + pg_block_size) : (op->offset + op->len);
        op->parts[i] = {
            .parent = op,
            .offset = begin,
            .len = (uint32_t)(end - begin),
            .pg_num = pg_num,
            .sent = false,
            .done = false,
        };
        int left = end-begin;
        while (left > 0 && iov_idx < op->iov.count)
        {
            if (op->iov.buf[iov_idx].iov_len - iov_pos < left)
            {
                op->parts[i].iov.push_back(op->iov.buf[iov_idx].iov_base + iov_pos, op->iov.buf[iov_idx].iov_len - iov_pos);
                left -= (op->iov.buf[iov_idx].iov_len - iov_pos);
                iov_pos = 0;
                iov_idx++;
            }
            else
            {
                op->parts[i].iov.push_back(op->iov.buf[iov_idx].iov_base + iov_pos, left);
                iov_pos += left;
                left = 0;
            }
        }
        assert(left == 0);
        i++;
    }
 }
 bool cluster_client_t::try_send(cluster_op_t *op, cluster_op_part_t *part)
 {
    auto & pool_cfg = st_cli.pool_config[INODE_POOL(op->inode)];
    auto pg_it = pool_cfg.pg_config.find(part->pg_num);
    if (pg_it != pool_cfg.pg_config.end() &&
        !pg_it->second.pause && pg_it->second.cur_primary)
    {
        osd_num_t primary_osd = pg_it->second.cur_primary;
        auto peer_it = msgr.osd_peer_fds.find(primary_osd);
        if (peer_it != msgr.osd_peer_fds.end())
        {
            int peer_fd = peer_it->second;
            part->osd_num = primary_osd;
            part->sent = true;
            op->sent_count++;
            part->op = {
                .op_type = OSD_OP_OUT,
                .peer_fd = peer_fd,
                .req = { .rw = {
                    .header = {
                        .magic = SECONDARY_OSD_OP_MAGIC,
                        .id = op_id++,
                        .opcode = op->opcode,
                    },
                    .inode = op->inode,
                    .offset = part->offset,
                    .len = part->len,
                } },
                .callback = [this, part](osd_op_t *op_part)
                {
                    handle_op_part(part);
                },
            };
            part->op.iov = part->iov;
            msgr.outbox_push(&part->op);
            return true;
        }
        else if (msgr.wanted_peers.find(primary_osd) == msgr.wanted_peers.end())
        {
            msgr.connect_peer(primary_osd, st_cli.peer_states[primary_osd]);
        }
    }
    return false;
 }
 void cluster_client_t::execute_sync(cluster_op_t *op)
 {
    if (immediate_commit)
    {
        // Syncs are not required in the immediate_commit mode
        op->retval = 0;
        std::function<void(cluster_op_t*)>(op->callback)(op);
    }
    else if (cur_sync != NULL)
    {
        next_writes.push_back(op);
    }
    else
    {
        cur_sync = op;
        continue_sync();
    }
 }
 void cluster_client_t::continue_sync()
 {
    if (!cur_sync || cur_sync->parts.size() > 0)
    {
        // Already submitted
        return;
    }
    cur_sync->retval = 0;
    std::set<osd_num_t> sync_osds;
    for (auto prev_op: unsynced_writes)
    {
        if (prev_op->done_count < prev_op->parts.size())
        {
            // Writes not finished yet
            return;
        }
        for (auto & part: prev_op->parts)
        {
            if (part.osd_num)
            {
                sync_osds.insert(part.osd_num);
            }
        }
    }
    if (!sync_osds.size())
    {
        // No dirty writes
        finish_sync();
        return;
    }
    // Check that all OSD connections are still alive
    for (auto sync_osd: sync_osds)
    {
        auto peer_it = msgr.osd_peer_fds.find(sync_osd);
        if (peer_it == msgr.osd_peer_fds.end())
        {
            // SYNC is pointless to send to a non connected OSD
            return;
        }
    }
    syncing_writes.swap(unsynced_writes);
    // Post sync to affected OSDs
    cur_sync->parts.resize(sync_osds.size());
    int i = 0;
    for (auto sync_osd: sync_osds)
    {
        cur_sync->parts[i] = {
            .parent = cur_sync,
            .osd_num = sync_osd,
            .sent = false,
            .done = false,
        };
        send_sync(cur_sync, &cur_sync->parts[i]);
        i++;
    }
 }
 void cluster_client_t::finish_sync()
 {
    int retval = cur_sync->retval;
    if (retval != 0)
    {
        for (auto op: syncing_writes)
        {
            if (op->done_count < op->parts.size())
            {
                cur_ops.insert(op);
            }
        }
        unsynced_writes.insert(unsynced_writes.begin(), syncing_writes.begin(), syncing_writes.end());
        syncing_writes.clear();
    }
    if (retval == -EPIPE)
    {
        // Retry later
        cur_sync->parts.clear();
        cur_sync->retval = 0;
        cur_sync->sent_count = 0;
        cur_sync->done_count = 0;
        return;
    }
    std::function<void(cluster_op_t*)>(cur_sync->callback)(cur_sync);
    if (!retval)
    {
        for (auto op: syncing_writes)
        {
            assert(op->sent_count == 0);
            if (op->is_internal)
            {
                if (op->buf)
                    free(op->buf);
                delete op;
            }
        }
        syncing_writes.clear();
    }
    cur_sync = NULL;
    queued_bytes = 0;
    std::vector<cluster_op_t*> next_wr_copy;
    next_wr_copy.swap(next_writes);
    for (auto next_op: next_wr_copy)
    {
        execute(next_op);
    }
 }
 void cluster_client_t::send_sync(cluster_op_t *op, cluster_op_part_t *part)
 {
    auto peer_it = msgr.osd_peer_fds.find(part->osd_num);
    assert(peer_it != msgr.osd_peer_fds.end());
    part->sent = true;
    op->sent_count++;
    part->op = {
        .op_type = OSD_OP_OUT,
        .peer_fd = peer_it->second,
        .req = {
            .hdr = {
                .magic = SECONDARY_OSD_OP_MAGIC,
                .id = op_id++,
                .opcode = OSD_OP_SYNC,
            },
        },
        .callback = [this, part](osd_op_t *op_part)
        {
            handle_op_part(part);
        },
    };
    msgr.outbox_push(&part->op);
 }
 void cluster_client_t::handle_op_part(cluster_op_part_t *part)
 {
    cluster_op_t *op = part->parent;
    part->sent = false;
    op->sent_count--;
    int expected = part->op.req.hdr.opcode == OSD_OP_SYNC ? 0 : part->op.req.rw.len;
    if (part->op.reply.hdr.retval != expected)
    {
        // Operation failed, retry
        printf(
            "Operation failed on OSD %lu: retval=%ld (expected %d), dropping connection\n",
            part->osd_num, part->op.reply.hdr.retval, expected
        );
        msgr.stop_client(part->op.peer_fd);
        if (part->op.reply.hdr.retval == -EPIPE)
        {
            op->up_wait = true;
            if (!retry_timeout_id)
            {
                retry_timeout_id = tfd->set_timer(up_wait_retry_interval, false, [this](int)
                {
                    retry_timeout_id = 0;
                    continue_ops(true);
                });
            }
        }
        if (!op->retval || op->retval == -EPIPE)
        {
            // Don't overwrite other errors with -EPIPE
            op->retval = part->op.reply.hdr.retval;
        }
    }
    else
    {
        // OK
        part->done = true;
        op->done_count++;
    }
    if (op->sent_count == 0)
    {
        if (op->opcode == OSD_OP_SYNC)
        {
            assert(op == cur_sync);
            finish_sync();
        }
        else
        {
            continue_rw(op);
        }
    }
 }
--- a/cluster_client.h
+++ b/cluster_client.h
@ -1,102 +0,0 @@
 // Copyright (c) Vitaliy Filippov, 2019+
 // License: VNPL-1.0 or GNU GPL-2.0+ (see README.md for details)
 #pragma once
 #include "messenger.h"
 #include "etcd_state_client.h"
 #define MIN_BLOCK_SIZE 4*1024
 #define MAX_BLOCK_SIZE 128*1024*1024
 #define DEFAULT_BLOCK_SIZE 128*1024
 #define DEFAULT_DISK_ALIGNMENT 4096
 #define DEFAULT_BITMAP_GRANULARITY 4096
 #define DEFAULT_CLIENT_DIRTY_LIMIT 32*1024*1024
 struct cluster_op_t;
 struct cluster_op_part_t
 {
    cluster_op_t *parent;
    uint64_t offset;
    uint32_t len;
    pg_num_t pg_num;
    osd_num_t osd_num;
    osd_op_buf_list_t iov;
    bool sent;
    bool done;
    osd_op_t op;
 };
 struct cluster_op_t
 {
    uint64_t opcode; // OSD_OP_READ, OSD_OP_WRITE, OSD_OP_SYNC
    uint64_t inode;
    uint64_t offset;
    uint64_t len;
    int retval;
    osd_op_buf_list_t iov;
    std::function<void(cluster_op_t*)> callback;
 protected:
    void *buf = NULL;
    cluster_op_t *orig_op = NULL;
    bool is_internal = false;
    bool needs_reslice = false;
    bool up_wait = false;
    int sent_count = 0, done_count = 0;
    std::vector<cluster_op_part_t> parts;
    friend class cluster_client_t;
 };
 class cluster_client_t
 {
    timerfd_manager_t *tfd;
    ring_loop_t *ringloop;
    uint64_t bs_block_size = 0;
    uint64_t bs_disk_alignment = 0;
    uint64_t bs_bitmap_granularity = 0;
    std::map<pool_id_t, uint64_t> pg_counts;
    bool immediate_commit = false;
    // FIXME: Implement inmemory_commit mode. Note that it requires to return overlapping reads from memory.
    uint64_t client_dirty_limit = 0;
    int log_level;
    int up_wait_retry_interval = 500; // ms
    uint64_t op_id = 1;
    etcd_state_client_t st_cli;
    osd_messenger_t msgr;
    ring_consumer_t consumer;
    // operations currently in progress
    std::set<cluster_op_t*> cur_ops;
    int retry_timeout_id = 0;
    // unsynced operations are copied in memory to allow replay when cluster isn't in the immediate_commit mode
    // unsynced_writes are replayed in any order (because only the SYNC operation guarantees ordering)
    std::vector<cluster_op_t*> unsynced_writes;
    std::vector<cluster_op_t*> syncing_writes;
    cluster_op_t* cur_sync = NULL;
    std::vector<cluster_op_t*> next_writes;
    std::vector<cluster_op_t*> offline_ops;
    uint64_t queued_bytes = 0;
 public:
    cluster_client_t(ring_loop_t *ringloop, timerfd_manager_t *tfd, json11::Json & config);
    ~cluster_client_t();
    void execute(cluster_op_t *op);
    void stop();
 protected:
    void continue_ops(bool up_retry = false);
    void on_load_config_hook(json11::Json::object & config);
    void on_load_pgs_hook(bool success);
    void on_change_hook(json11::Json::object & changes);
    void on_change_osd_state_hook(uint64_t peer_osd);
    void continue_rw(cluster_op_t *op);
    void slice_rw(cluster_op_t *op);
    bool try_send(cluster_op_t *op, cluster_op_part_t *part);
    void execute_sync(cluster_op_t *op);
    void continue_sync();
    void finish_sync();
    void send_sync(cluster_op_t *op, cluster_op_part_t *part);
    void handle_op_part(cluster_op_part_t *part);
 };
--- a/1
+++ b/1
@ -1 +0,0 @@
 Subproject commit 5dc108754ad40d3b1d024f9bd7cca0595ef1a1db
--- a/dump_journal.cpp
+++ b/dump_journal.cpp
@ -1,173 +0,0 @@
 // Copyright (c) Vitaliy Filippov, 2019+
 // License: VNPL-1.0 (see README.md for details)
 #define _LARGEFILE64_SOURCE
 #include <sys/types.h>
 #include <sys/ioctl.h>
 #include <sys/stat.h>
 #include <sys/time.h>
 #include <fcntl.h>
 #include <unistd.h>
 #include <stdint.h>
 #include <malloc.h>
 #include <linux/fs.h>
 #include <string.h>
 #include <errno.h>
 #include <assert.h>
 #include <stdio.h>
 #include "blockstore_impl.h"
 #include "crc32c.h"
 struct journal_dump_t
 {
    char *journal_device;
    uint32_t journal_block;
    uint64_t journal_offset;
    uint64_t journal_len;
    uint64_t journal_pos;
    int fd;
    void dump_block(void *buf);
 };
 int main(int argc, char *argv[])
 {
    if (argc < 5)
    {
        printf("USAGE: %s <journal_file> <journal_block_size> <offset> <size>\n", argv[0]);
        return 1;
    }
    journal_dump_t self;
    self.journal_device = argv[1];
    self.journal_block = strtoul(argv[2], NULL, 10);
    self.journal_offset = strtoull(argv[3], NULL, 10);
    self.journal_len = strtoull(argv[4], NULL, 10);
    if (self.journal_block < MEM_ALIGNMENT || (self.journal_block % MEM_ALIGNMENT) ||
        self.journal_block > 128*1024)
    {
        printf("Invalid journal block size\n");
        return 1;
    }
    self.fd = open(self.journal_device, O_DIRECT|O_RDONLY);
    if (self.fd == -1)
    {
        printf("Failed to open journal\n");
        return 1;
    }
    void *data = memalign(MEM_ALIGNMENT, self.journal_block);
    self.journal_pos = 0;
    while (self.journal_pos < self.journal_len)
    {
        int r = pread(self.fd, data, self.journal_block, self.journal_offset+self.journal_pos);
        assert(r == self.journal_block);
        uint64_t s;
        for (s = 0; s < self.journal_block; s += 8)
        {
            if (*((uint64_t*)(data+s)) != 0)
                break;
        }
        if (s == self.journal_block)
        {
            printf("offset %08lx: zeroes\n", self.journal_pos);
            self.journal_pos += self.journal_block;
        }
        else if (((journal_entry*)data)->magic == JOURNAL_MAGIC)
        {
            printf("offset %08lx:\n", self.journal_pos);
            self.dump_block(data);
        }
        else
        {
            printf("offset %08lx: no magic in the beginning, looks like random data (pattern=%lx)\n", self.journal_pos, *((uint64_t*)data));
            self.journal_pos += self.journal_block;
        }
    }
    free(data);
    close(self.fd);
    return 0;
 }
 void journal_dump_t::dump_block(void *buf)
 {
    uint32_t pos = 0;
    journal_pos += journal_block;
    int entry = 0;
    bool wrapped = false;
    while (pos < journal_block)
    {
        journal_entry *je = (journal_entry*)(buf + pos);
        if (je->magic != JOURNAL_MAGIC || je->type < JE_MIN || je->type > JE_MAX)
        {
            break;
        }
        const char *crc32_valid = je_crc32(je) == je->crc32 ? "(valid)" : "(invalid)";
        printf("entry % 3d: crc32=%08x %s prev=%08x ", entry, je->crc32, crc32_valid, je->crc32_prev);
        if (je->type == JE_START)
        {
            printf("je_start start=%08lx\n", je->start.journal_start);
        }
        else if (je->type == JE_SMALL_WRITE || je->type == JE_SMALL_WRITE_INSTANT)
        {
            printf(
                "je_small_write%s oid=%lx:%lx ver=%lu offset=%u len=%u loc=%08lx",
                je->type == JE_SMALL_WRITE_INSTANT ? "_instant" : "",
                je->small_write.oid.inode, je->small_write.oid.stripe,
                je->small_write.version, je->small_write.offset, je->small_write.len,
                je->small_write.data_offset
            );
            if (journal_pos + je->small_write.len > journal_len)
            {
                // data continues from the beginning of the journal
                journal_pos = journal_block;
                wrapped = true;
            }
            if (journal_pos != je->small_write.data_offset)
            {
                printf(" (mismatched, calculated = %lu)", journal_pos);
            }
            journal_pos += je->small_write.len;
            if (journal_pos >= journal_len)
            {
                journal_pos = journal_block;
                wrapped = true;
            }
            uint32_t data_crc32 = 0;
            void *data = memalign(MEM_ALIGNMENT, je->small_write.len);
            assert(pread(fd, data, je->small_write.len, journal_offset+je->small_write.data_offset) == je->small_write.len);
            data_crc32 = crc32c(0, data, je->small_write.len);
            free(data);
            printf(
                " data_crc32=%08x%s", je->small_write.crc32_data,
                (data_crc32 != je->small_write.crc32_data) ? " (invalid)" : " (valid)"
            );
            printf("\n");
        }
        else if (je->type == JE_BIG_WRITE || je->type == JE_BIG_WRITE_INSTANT)
        {
            printf(
                "je_big_write%s oid=%lx:%lx ver=%lu loc=%08lx\n",
                je->type == JE_BIG_WRITE_INSTANT ? "_instant" : "",
                je->big_write.oid.inode, je->big_write.oid.stripe, je->big_write.version, je->big_write.location
            );
        }
        else if (je->type == JE_STABLE)
        {
            printf("je_stable oid=%lx:%lx ver=%lu\n", je->stable.oid.inode, je->stable.oid.stripe, je->stable.version);
        }
        else if (je->type == JE_ROLLBACK)
        {
            printf("je_rollback oid=%lx:%lx ver=%lu\n", je->rollback.oid.inode, je->rollback.oid.stripe, je->rollback.version);
        }
        else if (je->type == JE_DELETE)
        {
            printf("je_delete oid=%lx:%lx ver=%lu\n", je->del.oid.inode, je->del.oid.stripe, je->del.version);
        }
        pos += je->size;
        entry++;
    }
    if (wrapped)
    {
        journal_pos = journal_len;
    }
 }
--- a/epoll_manager.cpp
+++ b/epoll_manager.cpp
@ -1,90 +0,0 @@
 // Copyright (c) Vitaliy Filippov, 2019+
 // License: VNPL-1.0 or GNU GPL-2.0+ (see README.md for details)
 #include <sys/epoll.h>
 #include <sys/poll.h>
 #include <unistd.h>
 #include "epoll_manager.h"
 #define MAX_EPOLL_EVENTS 64
 epoll_manager_t::epoll_manager_t(ring_loop_t *ringloop)
 {
    this->ringloop = ringloop;
    epoll_fd = epoll_create(1);
    if (epoll_fd < 0)
    {
        throw std::runtime_error(std::string("epoll_create: ") + strerror(errno));
    }
    tfd = new timerfd_manager_t([this](int fd, bool wr, std::function<void(int, int)> handler) { set_fd_handler(fd, wr, handler); });
    handle_epoll_events();
 }
 epoll_manager_t::~epoll_manager_t()
 {
    if (tfd)
    {
        delete tfd;
        tfd = NULL;
    }
    close(epoll_fd);
 }
 void epoll_manager_t::set_fd_handler(int fd, bool wr, std::function<void(int, int)> handler)
 {
    if (handler != NULL)
    {
        bool exists = epoll_handlers.find(fd) != epoll_handlers.end();
        epoll_event ev;
        ev.data.fd = fd;
        ev.events = (wr ? EPOLLOUT : 0) | EPOLLIN | EPOLLRDHUP | EPOLLET;
        if (epoll_ctl(epoll_fd, exists ? EPOLL_CTL_MOD : EPOLL_CTL_ADD, fd, &ev) < 0)
        {
            throw std::runtime_error(std::string("epoll_ctl: ") + strerror(errno));
        }
        epoll_handlers[fd] = handler;
    }
    else
    {
        if (epoll_ctl(epoll_fd, EPOLL_CTL_DEL, fd, NULL) < 0 && errno != ENOENT)
        {
            throw std::runtime_error(std::string("epoll_ctl: ") + strerror(errno));
        }
        epoll_handlers.erase(fd);
    }
 }
 void epoll_manager_t::handle_epoll_events()
 {
    io_uring_sqe *sqe = ringloop->get_sqe();
    if (!sqe)
    {
        throw std::runtime_error("can't get SQE, will fall out of sync with EPOLLET");
    }
    ring_data_t *data = ((ring_data_t*)sqe->user_data);
    my_uring_prep_poll_add(sqe, epoll_fd, POLLIN);
    data->callback = [this](ring_data_t *data)
    {
        if (data->res < 0)
        {
            throw std::runtime_error(std::string("epoll failed: ") + strerror(-data->res));
        }
        handle_epoll_events();
    };
    ringloop->submit();
    int nfds;
    epoll_event events[MAX_EPOLL_EVENTS];
    do
    {
        nfds = epoll_wait(epoll_fd, events, MAX_EPOLL_EVENTS, 0);
        for (int i = 0; i < nfds; i++)
        {
            auto & cb = epoll_handlers[events[i].data.fd];
            cb(events[i].data.fd, events[i].events);
        }
    } while (nfds == MAX_EPOLL_EVENTS);
 }
--- a/epoll_manager.h
+++ b/epoll_manager.h
@ -1,23 +0,0 @@
 // Copyright (c) Vitaliy Filippov, 2019+
 // License: VNPL-1.0 or GNU GPL-2.0+ (see README.md for details)
 #pragma once
 #include <map>
 #include "ringloop.h"
 #include "timerfd_manager.h"
 class epoll_manager_t
 {
    int epoll_fd;
    ring_loop_t *ringloop;
    std::map<int, std::function<void(int, int)>> epoll_handlers;
 public:
    epoll_manager_t(ring_loop_t *ringloop);
    ~epoll_manager_t();
    void set_fd_handler(int fd, bool wr, std::function<void(int, int)> handler);
    void handle_epoll_events();
    timerfd_manager_t *tfd;
 };
--- a/etcd_state_client.cpp
+++ b/etcd_state_client.cpp
@ -1,556 +0,0 @@
 // Copyright (c) Vitaliy Filippov, 2019+
 // License: VNPL-1.0 or GNU GPL-2.0+ (see README.md for details)
 #include "osd_ops.h"
 #include "pg_states.h"
 #include "etcd_state_client.h"
 #include "http_client.h"
 #include "base64.h"
 json_kv_t etcd_state_client_t::parse_etcd_kv(const json11::Json & kv_json)
 {
    json_kv_t kv;
    kv.key = base64_decode(kv_json["key"].string_value());
    std::string json_err, json_text = base64_decode(kv_json["value"].string_value());
    kv.value = json_text == "" ? json11::Json() : json11::Json::parse(json_text, json_err);
    if (json_err != "")
    {
        printf("Bad JSON in etcd key %s: %s (value: %s)\n", kv.key.c_str(), json_err.c_str(), json_text.c_str());
        kv.key = "";
    }
    return kv;
 }
 void etcd_state_client_t::etcd_txn(json11::Json txn, int timeout, std::function<void(std::string, json11::Json)> callback)
 {
    etcd_call("/kv/txn", txn, timeout, callback);
 }
 void etcd_state_client_t::etcd_call(std::string api, json11::Json payload, int timeout, std::function<void(std::string, json11::Json)> callback)
 {
    std::string etcd_address = etcd_addresses[rand() % etcd_addresses.size()];
    std::string etcd_api_path;
    int pos = etcd_address.find('/');
    if (pos >= 0)
    {
        etcd_api_path = etcd_address.substr(pos);
        etcd_address = etcd_address.substr(0, pos);
    }
    std::string req = payload.dump();
    req = "POST "+etcd_api_path+api+" HTTP/1.1\r\n"
        "Host: "+etcd_address+"\r\n"
        "Content-Type: application/json\r\n"
        "Content-Length: "+std::to_string(req.size())+"\r\n"
        "Connection: close\r\n"
        "\r\n"+req;
    http_request_json(tfd, etcd_address, req, timeout, callback);
 }
 void etcd_state_client_t::parse_config(json11::Json & config)
 {
    this->etcd_addresses.clear();
    if (config["etcd_address"].is_string())
    {
        std::string ea = config["etcd_address"].string_value();
        while (1)
        {
            int pos = ea.find(',');
            std::string addr = pos >= 0 ? ea.substr(0, pos) : ea;
            if (addr.length() > 0)
            {
                if (addr.find('/') < 0)
                    addr += "/v3";
                this->etcd_addresses.push_back(addr);
            }
            if (pos >= 0)
                ea = ea.substr(pos+1);
            else
                break;
        }
    }
    else if (config["etcd_address"].array_items().size())
    {
        for (auto & ea: config["etcd_address"].array_items())
        {
            std::string addr = ea.string_value();
            if (addr != "")
            {
                if (addr.find('/') < 0)
                    addr += "/v3";
                this->etcd_addresses.push_back(addr);
            }
        }
    }
    this->etcd_prefix = config["etcd_prefix"].string_value();
    if (this->etcd_prefix == "")
    {
        this->etcd_prefix = "/vitastor";
    }
    else if (this->etcd_prefix[0] != '/')
    {
        this->etcd_prefix = "/"+this->etcd_prefix;
    }
    this->log_level = config["log_level"].int64_value();
 }
 void etcd_state_client_t::start_etcd_watcher()
 {
    std::string etcd_address = etcd_addresses[rand() % etcd_addresses.size()];
    std::string etcd_api_path;
    int pos = etcd_address.find('/');
    if (pos >= 0)
    {
        etcd_api_path = etcd_address.substr(pos);
        etcd_address = etcd_address.substr(0, pos);
    }
    etcd_watches_initialised = 0;
    etcd_watch_ws = open_websocket(tfd, etcd_address, etcd_api_path+"/watch", ETCD_SLOW_TIMEOUT, [this](const http_response_t *msg)
    {
        if (msg->body.length())
        {
            std::string json_err;
            json11::Json data = json11::Json::parse(msg->body, json_err);
            if (json_err != "")
            {
                printf("Bad JSON in etcd event: %s, ignoring event\n", json_err.c_str());
            }
            else
            {
                if (data["result"]["created"].bool_value())
                {
                    etcd_watches_initialised++;
                }
                if (etcd_watches_initialised == 4)
                {
                    etcd_watch_revision = data["result"]["header"]["revision"].uint64_value();
                }
                // First gather all changes into a hash to remove multiple overwrites
                json11::Json::object changes;
                for (auto & ev: data["result"]["events"].array_items())
                {
                    auto kv = parse_etcd_kv(ev["kv"]);
                    if (kv.key != "")
                    {
                        changes[kv.key] = kv.value;
                    }
                }
                for (auto & kv: changes)
                {
                    if (this->log_level > 0)
                    {
                        printf("Incoming event: %s -> %s\n", kv.first.c_str(), kv.second.dump().c_str());
                    }
                    parse_state(kv.first, kv.second);
                }
                // React to changes
                if (on_change_hook != NULL)
                {
                    on_change_hook(changes);
                }
            }
        }
        if (msg->eof)
        {
            etcd_watch_ws = NULL;
            if (etcd_watches_initialised == 0)
            {
                // Connection not established, retry in <ETCD_SLOW_TIMEOUT>
                tfd->set_timer(ETCD_SLOW_TIMEOUT, false, [this](int)
                {
                    start_etcd_watcher();
                });
            }
            else
            {
                // Connection was live, retry immediately
                start_etcd_watcher();
            }
        }
    });
    etcd_watch_ws->post_message(WS_TEXT, json11::Json(json11::Json::object {
        { "create_request", json11::Json::object {
            { "key", base64_encode(etcd_prefix+"/config/") },
            { "range_end", base64_encode(etcd_prefix+"/config0") },
            { "start_revision", etcd_watch_revision+1 },
            { "watch_id", ETCD_CONFIG_WATCH_ID },
        } }
    }).dump());
    etcd_watch_ws->post_message(WS_TEXT, json11::Json(json11::Json::object {
        { "create_request", json11::Json::object {
            { "key", base64_encode(etcd_prefix+"/osd/state/") },
            { "range_end", base64_encode(etcd_prefix+"/osd/state0") },
            { "start_revision", etcd_watch_revision+1 },
            { "watch_id", ETCD_OSD_STATE_WATCH_ID },
        } }
    }).dump());
    etcd_watch_ws->post_message(WS_TEXT, json11::Json(json11::Json::object {
        { "create_request", json11::Json::object {
            { "key", base64_encode(etcd_prefix+"/pg/state/") },
            { "range_end", base64_encode(etcd_prefix+"/pg/state0") },
            { "start_revision", etcd_watch_revision+1 },
            { "watch_id", ETCD_PG_STATE_WATCH_ID },
        } }
    }).dump());
    etcd_watch_ws->post_message(WS_TEXT, json11::Json(json11::Json::object {
        { "create_request", json11::Json::object {
            { "key", base64_encode(etcd_prefix+"/pg/history/") },
            { "range_end", base64_encode(etcd_prefix+"/pg/history0") },
            { "start_revision", etcd_watch_revision+1 },
            { "watch_id", ETCD_PG_HISTORY_WATCH_ID },
        } }
    }).dump());
 }
 void etcd_state_client_t::load_global_config()
 {
    etcd_call("/kv/range", json11::Json::object {
        { "key", base64_encode(etcd_prefix+"/config/global") }
    }, ETCD_SLOW_TIMEOUT, [this](std::string err, json11::Json data)
    {
        if (err != "")
        {
            printf("Error reading OSD configuration from etcd: %s\n", err.c_str());
            tfd->set_timer(ETCD_SLOW_TIMEOUT, false, [this](int timer_id)
            {
                load_global_config();
            });
            return;
        }
        if (!etcd_watch_revision)
        {
            etcd_watch_revision = data["header"]["revision"].uint64_value();
        }
        json11::Json::object global_config;
        if (data["kvs"].array_items().size() > 0)
        {
            auto kv = parse_etcd_kv(data["kvs"][0]);
            if (kv.value.is_object())
            {
                global_config = kv.value.object_items();
            }
        }
        on_load_config_hook(global_config);
    });
 }
 void etcd_state_client_t::load_pgs()
 {
    json11::Json::array txn = {
        json11::Json::object {
            { "request_range", json11::Json::object {
                { "key", base64_encode(etcd_prefix+"/config/pools") },
            } }
        },
        json11::Json::object {
            { "request_range", json11::Json::object {
                { "key", base64_encode(etcd_prefix+"/config/pgs") },
            } }
        },
        json11::Json::object {
            { "request_range", json11::Json::object {
                { "key", base64_encode(etcd_prefix+"/pg/history/") },
                { "range_end", base64_encode(etcd_prefix+"/pg/history0") },
            } }
        },
        json11::Json::object {
            { "request_range", json11::Json::object {
                { "key", base64_encode(etcd_prefix+"/pg/state/") },
                { "range_end", base64_encode(etcd_prefix+"/pg/state0") },
            } }
        },
        json11::Json::object {
            { "request_range", json11::Json::object {
                { "key", base64_encode(etcd_prefix+"/osd/state/") },
                { "range_end", base64_encode(etcd_prefix+"/osd/state0") },
            } }
        },
    };
    json11::Json::object req = { { "success", txn } };
    json11::Json checks = load_pgs_checks_hook != NULL ? load_pgs_checks_hook() : json11::Json();
    if (checks.array_items().size() > 0)
    {
        req["compare"] = checks;
    }
    etcd_txn(req, ETCD_SLOW_TIMEOUT, [this](std::string err, json11::Json data)
    {
        if (err != "")
        {
            printf("Error loading PGs from etcd: %s\n", err.c_str());
            tfd->set_timer(ETCD_SLOW_TIMEOUT, false, [this](int timer_id)
            {
                load_pgs();
            });
            return;
        }
        if (!data["succeeded"].bool_value())
        {
            on_load_pgs_hook(false);
            return;
        }
        for (auto & res: data["responses"].array_items())
        {
            for (auto & kv_json: res["response_range"]["kvs"].array_items())
            {
                auto kv = parse_etcd_kv(kv_json);
                parse_state(kv.key, kv.value);
            }
        }
        on_load_pgs_hook(true);
    });
 }
 void etcd_state_client_t::parse_state(const std::string & key, const json11::Json & value)
 {
    if (key == etcd_prefix+"/config/pools")
    {
        for (auto & pool_item: this->pool_config)
        {
            pool_item.second.exists = false;
        }
        for (auto & pool_item: value.object_items())
        {
            pool_id_t pool_id = stoull_full(pool_item.first);
            if (!pool_id || pool_id >= POOL_ID_MAX)
            {
                printf("Pool ID %s is invalid (must be a number less than 0x%x), skipping pool\n", pool_item.first.c_str(), POOL_ID_MAX);
                continue;
            }
            if (pool_item.second["pg_size"].uint64_value() < 1 ||
                pool_item.second["scheme"] == "xor" && pool_item.second["pg_size"].uint64_value() < 3)
            {
                printf("Pool %u has invalid pg_size, skipping pool\n", pool_id);
                continue;
            }
            if (pool_item.second["pg_minsize"].uint64_value() < 1 ||
                pool_item.second["pg_minsize"].uint64_value() > pool_item.second["pg_size"].uint64_value() ||
                pool_item.second["pg_minsize"].uint64_value() < (pool_item.second["pg_size"].uint64_value() - 1))
            {
                printf("Pool %u has invalid pg_minsize, skipping pool\n", pool_id);
                continue;
            }
            if (pool_item.second["pg_count"].uint64_value() < 1)
            {
                printf("Pool %u has invalid pg_count, skipping pool\n", pool_id);
                continue;
            }
            if (pool_item.second["name"].string_value() == "")
            {
                printf("Pool %u has empty name, skipping pool\n", pool_id);
                continue;
            }
            if (pool_item.second["scheme"] != "replicated" && pool_item.second["scheme"] != "xor")
            {
                printf("Pool %u has invalid coding scheme (only \"xor\" and \"replicated\" are allowed), skipping pool\n", pool_id);
                continue;
            }
            if (pool_item.second["max_osd_combinations"].uint64_value() > 0 &&
                pool_item.second["max_osd_combinations"].uint64_value() < 100)
            {
                printf("Pool %u has invalid max_osd_combinations (must be at least 100), skipping pool\n", pool_id);
                continue;
            }
            auto & parsed_cfg = this->pool_config[pool_id];
            parsed_cfg.exists = true;
            parsed_cfg.id = pool_id;
            parsed_cfg.name = pool_item.second["name"].string_value();
            parsed_cfg.scheme = pool_item.second["scheme"] == "replicated" ? POOL_SCHEME_REPLICATED : POOL_SCHEME_XOR;
            parsed_cfg.pg_size = pool_item.second["pg_size"].uint64_value();
            parsed_cfg.pg_minsize = pool_item.second["pg_minsize"].uint64_value();
            parsed_cfg.pg_count = pool_item.second["pg_count"].uint64_value();
            parsed_cfg.failure_domain = pool_item.second["failure_domain"].string_value();
            parsed_cfg.pg_stripe_size = pool_item.second["pg_stripe_size"].uint64_value();
            if (!parsed_cfg.pg_stripe_size)
            {
                parsed_cfg.pg_stripe_size = DEFAULT_PG_STRIPE_SIZE;
            }
            parsed_cfg.max_osd_combinations = pool_item.second["max_osd_combinations"].uint64_value();
            if (!parsed_cfg.max_osd_combinations)
            {
                parsed_cfg.max_osd_combinations = 10000;
            }
            for (auto & pg_item: parsed_cfg.pg_config)
            {
                if (pg_item.second.target_set.size() != parsed_cfg.pg_size)
                {
                    printf("Pool %u PG %u configuration is invalid: osd_set size %lu != pool pg_size %lu\n",
                        pool_id, pg_item.first, pg_item.second.target_set.size(), parsed_cfg.pg_size);
                    pg_item.second.pause = true;
                }
            }
        }
    }
    else if (key == etcd_prefix+"/config/pgs")
    {
        for (auto & pool_item: this->pool_config)
        {
            for (auto & pg_item: pool_item.second.pg_config)
            {
                pg_item.second.exists = false;
            }
        }
        for (auto & pool_item: value["items"].object_items())
        {
            pool_id_t pool_id = stoull_full(pool_item.first);
            if (!pool_id || pool_id >= POOL_ID_MAX)
            {
                printf("Pool ID %s is invalid in PG configuration (must be a number less than 0x%x), skipping pool\n", pool_item.first.c_str(), POOL_ID_MAX);
                continue;
            }
            for (auto & pg_item: pool_item.second.object_items())
            {
                pg_num_t pg_num = stoull_full(pg_item.first);
                if (!pg_num)
                {
                    printf("Bad key in pool %u PG configuration: %s (must be a number), skipped\n", pool_id, pg_item.first.c_str());
                    continue;
                }
                auto & parsed_cfg = this->pool_config[pool_id].pg_config[pg_num];
                parsed_cfg.exists = true;
                parsed_cfg.pause = pg_item.second["pause"].bool_value();
                parsed_cfg.primary = pg_item.second["primary"].uint64_value();
                parsed_cfg.target_set.clear();
                for (auto & pg_osd: pg_item.second["osd_set"].array_items())
                {
                    parsed_cfg.target_set.push_back(pg_osd.uint64_value());
                }
                if (parsed_cfg.target_set.size() != pool_config[pool_id].pg_size)
                {
                    printf("Pool %u PG %u configuration is invalid: osd_set size %lu != pool pg_size %lu\n",
                        pool_id, pg_num, parsed_cfg.target_set.size(), pool_config[pool_id].pg_size);
                    parsed_cfg.pause = true;
                }
            }
        }
        for (auto & pool_item: this->pool_config)
        {
            int n = 0;
            for (auto pg_it = pool_item.second.pg_config.begin(); pg_it != pool_item.second.pg_config.end(); pg_it++)
            {
                if (pg_it->second.exists && pg_it->first != ++n)
                {
                    printf(
                        "Invalid pool %u PG configuration: PG numbers don't cover whole 1..%lu range\n",
                        pool_item.second.id, pool_item.second.pg_config.size()
                    );
                    for (pg_it = pool_item.second.pg_config.begin(); pg_it != pool_item.second.pg_config.end(); pg_it++)
                    {
                        pg_it->second.exists = false;
                    }
                    n = 0;
                    break;
                }
            }
            pool_item.second.real_pg_count = n;
        }
    }
    else if (key.substr(0, etcd_prefix.length()+12) == etcd_prefix+"/pg/history/")
    {
        // <etcd_prefix>/pg/history/%d/%d
        pool_id_t pool_id = 0;
        pg_num_t pg_num = 0;
        char null_byte = 0;
        sscanf(key.c_str() + etcd_prefix.length()+12, "%u/%u%c", &pool_id, &pg_num, &null_byte);
        if (!pool_id || pool_id >= POOL_ID_MAX || !pg_num || null_byte != 0)
        {
            printf("Bad etcd key %s, ignoring\n", key.c_str());
        }
        else
        {
            auto & pg_cfg = this->pool_config[pool_id].pg_config[pg_num];
            pg_cfg.target_history.clear();
            pg_cfg.all_peers.clear();
            // Refuse to start PG if any set of the <osd_sets> has no live OSDs
            for (auto hist_item: value["osd_sets"].array_items())
            {
                std::vector<osd_num_t> history_set;
                for (auto pg_osd: hist_item.array_items())
                {
                    history_set.push_back(pg_osd.uint64_value());
                }
                pg_cfg.target_history.push_back(history_set);
            }
            // Include these additional OSDs when peering the PG
            for (auto pg_osd: value["all_peers"].array_items())
            {
                pg_cfg.all_peers.push_back(pg_osd.uint64_value());
            }
            // Read epoch
            pg_cfg.epoch = value["epoch"].uint64_value();
            if (on_change_pg_history_hook != NULL)
            {
                on_change_pg_history_hook(pool_id, pg_num);
            }
        }
    }
    else if (key.substr(0, etcd_prefix.length()+10) == etcd_prefix+"/pg/state/")
    {
        // <etcd_prefix>/pg/state/%d/%d
        pool_id_t pool_id = 0;
        pg_num_t pg_num = 0;
        char null_byte = 0;
        sscanf(key.c_str() + etcd_prefix.length()+10, "%u/%u%c", &pool_id, &pg_num, &null_byte);
        if (!pool_id || pool_id >= POOL_ID_MAX || !pg_num || null_byte != 0)
        {
            printf("Bad etcd key %s, ignoring\n", key.c_str());
        }
        else if (value.is_null())
        {
            this->pool_config[pool_id].pg_config[pg_num].cur_primary = 0;
            this->pool_config[pool_id].pg_config[pg_num].cur_state = 0;
        }
        else
        {
            osd_num_t cur_primary = value["primary"].uint64_value();
            int state = 0;
            for (auto & e: value["state"].array_items())
            {
                int i;
                for (i = 0; i < pg_state_bit_count; i++)
                {
                    if (e.string_value() == pg_state_names[i])
                    {
                        state = state | pg_state_bits[i];
                        break;
                    }
                }
                if (i >= pg_state_bit_count)
                {
                    printf("Unexpected pool %u PG %u state keyword in etcd: %s\n", pool_id, pg_num, e.dump().c_str());
                    return;
                }
            }
            if (!cur_primary || !value["state"].is_array() || !state ||
                (state & PG_OFFLINE) && state != PG_OFFLINE ||
                (state & PG_PEERING) && state != PG_PEERING ||
                (state & PG_INCOMPLETE) && state != PG_INCOMPLETE)
            {
                printf("Unexpected pool %u PG %u state in etcd: primary=%lu, state=%s\n", pool_id, pg_num, cur_primary, value["state"].dump().c_str());
                return;
            }
            this->pool_config[pool_id].pg_config[pg_num].cur_primary = cur_primary;
            this->pool_config[pool_id].pg_config[pg_num].cur_state = state;
        }
    }
    else if (key.substr(0, etcd_prefix.length()+11) == etcd_prefix+"/osd/state/")
    {
        // <etcd_prefix>/osd/state/%d
        osd_num_t peer_osd = std::stoull(key.substr(etcd_prefix.length()+11));
        if (peer_osd > 0)
        {
            if (value.is_object() && value["state"] == "up" &&
                value["addresses"].is_array() &&
                value["port"].int64_value() > 0 && value["port"].int64_value() < 65536)
            {
                this->peer_states[peer_osd] = value;
            }
            else
            {
                this->peer_states.erase(peer_osd);
            }
            if (on_change_osd_state_hook != NULL)
            {
                on_change_osd_state_hook(peer_osd);
            }
        }
    }
 }
--- a/etcd_state_client.h
+++ b/etcd_state_client.h
@ -1,83 +0,0 @@
 // Copyright (c) Vitaliy Filippov, 2019+
 // License: VNPL-1.0 or GNU GPL-2.0+ (see README.md for details)
 #pragma once
 #include "osd_id.h"
 #include "http_client.h"
 #include "timerfd_manager.h"
 #define ETCD_CONFIG_WATCH_ID 1
 #define ETCD_PG_STATE_WATCH_ID 2
 #define ETCD_PG_HISTORY_WATCH_ID 3
 #define ETCD_OSD_STATE_WATCH_ID 4
 #define MAX_ETCD_ATTEMPTS 5
 #define ETCD_SLOW_TIMEOUT 5000
 #define ETCD_QUICK_TIMEOUT 1000
 #define DEFAULT_PG_STRIPE_SIZE 4*1024*1024
 struct json_kv_t
 {
    std::string key;
    json11::Json value;
 };
 struct pg_config_t
 {
    bool exists;
    osd_num_t primary;
    std::vector<osd_num_t> target_set;
    std::vector<std::vector<osd_num_t>> target_history;
    std::vector<osd_num_t> all_peers;
    bool pause;
    osd_num_t cur_primary;
    int cur_state;
    uint64_t epoch;
 };
 struct pool_config_t
 {
    bool exists;
    pool_id_t id;
    std::string name;
    uint64_t scheme;
    uint64_t pg_size, pg_minsize;
    uint64_t pg_count;
    uint64_t real_pg_count;
    std::string failure_domain;
    uint64_t max_osd_combinations;
    uint64_t pg_stripe_size;
    std::map<pg_num_t, pg_config_t> pg_config;
 };
 struct etcd_state_client_t
 {
    std::vector<std::string> etcd_addresses;
    std::string etcd_prefix;
    int log_level = 0;
    timerfd_manager_t *tfd = NULL;
    int etcd_watches_initialised = 0;
    uint64_t etcd_watch_revision = 0;
    websocket_t *etcd_watch_ws = NULL;
    std::map<pool_id_t, pool_config_t> pool_config;
    std::map<osd_num_t, json11::Json> peer_states;
    std::function<void(json11::Json::object &)> on_change_hook;
    std::function<void(json11::Json::object &)> on_load_config_hook;
    std::function<json11::Json()> load_pgs_checks_hook;
    std::function<void(bool)> on_load_pgs_hook;
    std::function<void(pool_id_t, pg_num_t)> on_change_pg_history_hook;
    std::function<void(osd_num_t)> on_change_osd_state_hook;
    json_kv_t parse_etcd_kv(const json11::Json & kv_json);
    void etcd_call(std::string api, json11::Json payload, int timeout, std::function<void(std::string, json11::Json)> callback);
    void etcd_txn(json11::Json txn, int timeout, std::function<void(std::string, json11::Json)> callback);
    void start_etcd_watcher();
    void load_global_config();
    void load_pgs();
    void parse_state(const std::string & key, const json11::Json & value);
    void parse_config(json11::Json & config);
 };
--- a/fio_cluster.cpp
+++ b/fio_cluster.cpp
@ -1,338 +0,0 @@
 // Copyright (c) Vitaliy Filippov, 2019+
 // License: VNPL-1.0 or GNU GPL-2.0+ (see README.md for details)
 // FIO engine to test cluster I/O
 //
 // Random write:
 //
 // fio -thread -ioengine=./libfio_cluster.so -name=test -bs=4k -direct=1 -fsync=16 -iodepth=16 -rw=randwrite \
 //     -etcd=127.0.0.1:2379 [-etcd_prefix=/vitastor] -pool=1 -inode=1 -size=1000M
 //
 // Linear write:
 //
 // fio -thread -ioengine=./libfio_cluster.so -name=test -bs=128k -direct=1 -fsync=32 -iodepth=32 -rw=write \
 //     -etcd=127.0.0.1:2379 [-etcd_prefix=/vitastor] -pool=1 -inode=1 -size=1000M
 //
 // Random read (run with -iodepth=32 or -iodepth=1):
 //
 // fio -thread -ioengine=./libfio_cluster.so -name=test -bs=4k -direct=1 -iodepth=32 -rw=randread \
 //     -etcd=127.0.0.1:2379 [-etcd_prefix=/vitastor] -pool=1 -inode=1 -size=1000M
 #include <sys/types.h>
 #include <sys/socket.h>
 #include <netinet/in.h>
 #include <netinet/tcp.h>
 #include <vector>
 #include <unordered_map>
 #include "epoll_manager.h"
 #include "cluster_client.h"
 extern "C" {
 #define CONFIG_HAVE_GETTID
 #define CONFIG_PWRITEV2
 #include "fio/fio.h"
 #include "fio/optgroup.h"
 }
 struct sec_data
 {
    ring_loop_t *ringloop = NULL;
    epoll_manager_t *epmgr = NULL;
    cluster_client_t *cli = NULL;
    bool last_sync = false;
    /* The list of completed io_u structs. */
    std::vector<io_u*> completed;
    uint64_t op_n = 0, inflight = 0;
    bool trace = false;
 };
 struct sec_options
 {
    int __pad;
    char *etcd_host = NULL;
    char *etcd_prefix = NULL;
    uint64_t pool = 0;
    uint64_t inode = 0;
    int cluster_log = 0;
    int trace = 0;
 };
 static struct fio_option options[] = {
    {
        .name   = "etcd",
        .lname  = "etcd address",
        .type   = FIO_OPT_STR_STORE,
        .off1   = offsetof(struct sec_options, etcd_host),
        .help   = "etcd address in the form HOST:PORT[/PATH]",
        .category = FIO_OPT_C_ENGINE,
        .group  = FIO_OPT_G_FILENAME,
    },
    {
        .name   = "etcd",
        .lname  = "etcd key prefix",
        .type   = FIO_OPT_STR_STORE,
        .off1   = offsetof(struct sec_options, etcd_prefix),
        .help   = "etcd key prefix, by default /vitastor",
        .category = FIO_OPT_C_ENGINE,
        .group  = FIO_OPT_G_FILENAME,
    },
    {
        .name   = "pool",
        .lname  = "pool number for the inode",
        .type   = FIO_OPT_INT,
        .off1   = offsetof(struct sec_options, pool),
        .help   = "pool number for the inode to run tests on",
        .category = FIO_OPT_C_ENGINE,
        .group  = FIO_OPT_G_FILENAME,
    },
    {
        .name   = "inode",
        .lname  = "inode to run tests on",
        .type   = FIO_OPT_INT,
        .off1   = offsetof(struct sec_options, inode),
        .help   = "inode to run tests on (1 by default)",
        .category = FIO_OPT_C_ENGINE,
        .group  = FIO_OPT_G_FILENAME,
    },
    {
        .name   = "cluster_log_level",
        .lname  = "cluster log level",
        .type   = FIO_OPT_BOOL,
        .off1   = offsetof(struct sec_options, cluster_log),
        .help   = "Set log level for the Vitastor client",
        .def    = "0",
        .category = FIO_OPT_C_ENGINE,
        .group  = FIO_OPT_G_FILENAME,
    },
    {
        .name   = "osd_trace",
        .lname  = "OSD trace",
        .type   = FIO_OPT_BOOL,
        .off1   = offsetof(struct sec_options, trace),
        .help   = "Trace OSD operations",
        .def    = "0",
        .category = FIO_OPT_C_ENGINE,
        .group  = FIO_OPT_G_FILENAME,
    },
    {
        .name = NULL,
    },
 };
 static int sec_setup(struct thread_data *td)
 {
    sec_data *bsd;
    bsd = new sec_data;
    if (!bsd)
    {
        td_verror(td, errno, "calloc");
        return 1;
    }
    td->io_ops_data = bsd;
    if (!td->files_index)
    {
        add_file(td, "osd_cluster", 0, 0);
        td->o.nr_files = td->o.nr_files ? : 1;
        td->o.open_files++;
    }
    return 0;
 }
 static void sec_cleanup(struct thread_data *td)
 {
    sec_data *bsd = (sec_data*)td->io_ops_data;
    if (bsd)
    {
        delete bsd->cli;
        delete bsd->epmgr;
        delete bsd->ringloop;
        bsd->cli = NULL;
        bsd->epmgr = NULL;
        bsd->ringloop = NULL;
    }
 }
 /* Connect to the server from each thread. */
 static int sec_init(struct thread_data *td)
 {
    sec_options *o = (sec_options*)td->eo;
    sec_data *bsd = (sec_data*)td->io_ops_data;
    json11::Json cfg = json11::Json::object {
        { "etcd_address", std::string(o->etcd_host) },
        { "etcd_prefix", std::string(o->etcd_prefix ? o->etcd_prefix : "/vitastor") },
        { "log_level", o->cluster_log },
    };
    if (o->pool)
        o->inode = (o->inode & ((1l << (64-POOL_ID_BITS)) - 1)) | (o->pool << (64-POOL_ID_BITS));
    if (!(o->inode >> (64-POOL_ID_BITS)))
    {
        td_verror(td, EINVAL, "pool is missing");
        return 1;
    }
    bsd->ringloop = new ring_loop_t(512);
    bsd->epmgr = new epoll_manager_t(bsd->ringloop);
    bsd->cli = new cluster_client_t(bsd->ringloop, bsd->epmgr->tfd, cfg);
    bsd->trace = o->trace ? true : false;
    return 0;
 }
 /* Begin read or write request. */
 static enum fio_q_status sec_queue(struct thread_data *td, struct io_u *io)
 {
    sec_options *opt = (sec_options*)td->eo;
    sec_data *bsd = (sec_data*)td->io_ops_data;
    int n = bsd->op_n;
    fio_ro_check(td, io);
    if (io->ddir == DDIR_SYNC && bsd->last_sync)
    {
        return FIO_Q_COMPLETED;
    }
    io->engine_data = bsd;
    cluster_op_t *op = new cluster_op_t;
    switch (io->ddir)
    {
    case DDIR_READ:
        op->opcode = OSD_OP_READ;
        op->inode = opt->inode;
        op->offset = io->offset;
        op->len = io->xfer_buflen;
        op->iov.push_back(io->xfer_buf, io->xfer_buflen);
        bsd->last_sync = false;
        break;
    case DDIR_WRITE:
        op->opcode = OSD_OP_WRITE;
        op->inode = opt->inode;
        op->offset = io->offset;
        op->len = io->xfer_buflen;
        op->iov.push_back(io->xfer_buf, io->xfer_buflen);
        bsd->last_sync = false;
        break;
    case DDIR_SYNC:
        op->opcode = OSD_OP_SYNC;
        bsd->last_sync = true;
        break;
    default:
        io->error = EINVAL;
        return FIO_Q_COMPLETED;
    }
    op->callback = [io, n](cluster_op_t *op)
    {
        io->error = op->retval < 0 ? -op->retval : 0;
        sec_data *bsd = (sec_data*)io->engine_data;
        bsd->inflight--;
        bsd->completed.push_back(io);
        if (bsd->trace)
        {
            printf("--- %s n=%d retval=%d\n", io->ddir == DDIR_READ ? "READ" :
                (io->ddir == DDIR_WRITE ? "WRITE" : "SYNC"), n, op->retval);
        }
        delete op;
    };
    if (opt->trace)
    {
        if (io->ddir == DDIR_SYNC)
        {
            printf("+++ SYNC # %d\n", n);
        }
        else
        {
            printf("+++ %s # %d 0x%llx+%llx\n",
                io->ddir == DDIR_READ ? "READ" : "WRITE",
                n, io->offset, io->xfer_buflen);
        }
    }
    io->error = 0;
    bsd->inflight++;
    bsd->op_n++;
    bsd->cli->execute(op);
    if (io->error != 0)
        return FIO_Q_COMPLETED;
    return FIO_Q_QUEUED;
 }
 static int sec_getevents(struct thread_data *td, unsigned int min, unsigned int max, const struct timespec *t)
 {
    sec_data *bsd = (sec_data*)td->io_ops_data;
    while (true)
    {
        bsd->ringloop->loop();
        if (bsd->completed.size() >= min)
            break;
        bsd->ringloop->wait();
    }
    return bsd->completed.size();
 }
 static struct io_u *sec_event(struct thread_data *td, int event)
 {
    sec_data *bsd = (sec_data*)td->io_ops_data;
    if (bsd->completed.size() == 0)
        return NULL;
    /* FIXME We ignore the event number and assume fio calls us exactly once for [0..nr_events-1] */
    struct io_u *ev = bsd->completed.back();
    bsd->completed.pop_back();
    return ev;
 }
 static int sec_io_u_init(struct thread_data *td, struct io_u *io)
 {
    io->engine_data = NULL;
    return 0;
 }
 static void sec_io_u_free(struct thread_data *td, struct io_u *io)
 {
 }
 static int sec_open_file(struct thread_data *td, struct fio_file *f)
 {
    return 0;
 }
 static int sec_invalidate(struct thread_data *td, struct fio_file *f)
 {
    return 0;
 }
 struct ioengine_ops ioengine = {
    .name               = "vitastor_cluster",
    .version            = FIO_IOOPS_VERSION,
    .flags              = FIO_MEMALIGN | FIO_DISKLESSIO | FIO_NOEXTEND,
    .setup              = sec_setup,
    .init               = sec_init,
    .queue              = sec_queue,
    .getevents          = sec_getevents,
    .event              = sec_event,
    .cleanup            = sec_cleanup,
    .open_file          = sec_open_file,
    .invalidate         = sec_invalidate,
    .io_u_init          = sec_io_u_init,
    .io_u_free          = sec_io_u_free,
    .option_struct_size = sizeof(struct sec_options),
    .options            = options,
 };
 static void fio_init fio_sec_register(void)
 {
    register_ioengine(&ioengine);
 }
 static void fio_exit fio_sec_unregister(void)
 {
    unregister_ioengine(&ioengine);
 }
--- a/fio_engine.cpp
+++ b/fio_engine.cpp
@ -1,6 +1,3 @@
 // Copyright (c) Vitaliy Filippov, 2019+
 // License: VNPL-1.0 (see README.md for details)
 // FIO engine to test Blockstore
 //
 // Initialize storage for tests:
@ -26,7 +23,6 @@
 #include "blockstore.h"
 extern "C" {
 #define CONFIG_HAVE_GETTID
 #define CONFIG_PWRITEV2
 #include "fio/fio.h"
 #include "fio/optgroup.h"
@ -104,7 +100,7 @@ static void bs_cleanup(struct thread_data *td)
                bsd->ringloop->loop();
                if (bsd->bs->is_safe_to_stop())
                    goto safe;
-            } while (bsd->ringloop->has_work());
+            } while (bsd->ringloop->get_loop_again());
            bsd->ringloop->wait();
        }
    safe:
@ -293,7 +289,7 @@ static int bs_invalidate(struct thread_data *td, struct fio_file *f)
 }
 struct ioengine_ops ioengine = {
-    .name               = "vitastor_blockstore",
+    .name               = "microceph_blockstore",
    .version            = FIO_IOOPS_VERSION,
    .flags              = FIO_MEMALIGN | FIO_DISKLESSIO | FIO_NOEXTEND,
    .setup              = bs_setup,
--- a/fio_sec_osd.cpp
+++ b/fio_sec_osd.cpp
@ -1,6 +1,3 @@
 // Copyright (c) Vitaliy Filippov, 2019+
 // License: VNPL-1.0 or GNU GPL-2.0+ (see README.md for details)
 // FIO engine to test Blockstore through Secondary OSD interface
 //
 // Prepare storage like in fio_engine.cpp, then start OSD with ./osd, then test it
@ -8,7 +5,7 @@
 // Random write:
 //
 // fio -thread -ioengine=./libfio_sec_osd.so -name=test -bs=4k -direct=1 -fsync=16 -iodepth=16 -rw=randwrite \
-//     -host=127.0.0.1 -port=11203 [-block_size_order=17] [-single_primary=1] -size=1000M
+//     -host=127.0.0.1 -port=11203 [-single_primary=1] -size=1000M
 //
 // Linear write:
 //
@ -31,7 +28,6 @@
 #include "rw_blocking.h"
 #include "osd_ops.h"
 extern "C" {
 #define CONFIG_HAVE_GETTID
 #define CONFIG_PWRITEV2
 #include "fio/fio.h"
 #include "fio/optgroup.h"
@ -56,7 +52,6 @@ struct sec_options
    int port = 0;
    int single_primary = 0;
    int trace = 0;
    int block_order = 17;
 };
 static struct fio_option options[] = {
@ -78,15 +73,6 @@ static struct fio_option options[] = {
        .category = FIO_OPT_C_ENGINE,
        .group  = FIO_OPT_G_FILENAME,
    },
    {
        .name   = "block_size_order",
        .lname  = "Blockstore block size order",
        .type   = FIO_OPT_INT,
        .off1   = offsetof(struct sec_options, block_order),
        .help   = "Blockstore block size order (size = 2^order)",
        .category = FIO_OPT_C_ENGINE,
        .group  = FIO_OPT_G_FILENAME,
    },
    {
        .name   = "single_primary",
        .lname  = "Single Primary",
@ -153,8 +139,6 @@ static int sec_init(struct thread_data *td)
 {
    sec_options *o = (sec_options*)td->eo;
    sec_data *bsd = (sec_data*)td->io_ops_data;
    bsd->block_order = o->block_order == 0 ? 17 : o->block_order;
    bsd->block_size = 1 << o->block_order;
    struct sockaddr_in addr;
    int r;
@ -208,7 +192,7 @@ static enum fio_q_status sec_queue(struct thread_data *td, struct io_u *io)
    case DDIR_READ:
        if (!opt->single_primary)
        {
-            op.hdr.opcode = OSD_OP_SEC_READ;
+            op.hdr.opcode = OSD_OP_SECONDARY_READ;
            op.sec_rw.oid = {
                .inode = 1,
                .stripe = io->offset >> bsd->block_order,
@ -229,7 +213,7 @@ static enum fio_q_status sec_queue(struct thread_data *td, struct io_u *io)
    case DDIR_WRITE:
        if (!opt->single_primary)
        {
-            op.hdr.opcode = OSD_OP_SEC_WRITE;
+            op.hdr.opcode = OSD_OP_SECONDARY_WRITE;
            op.sec_rw.oid = {
                .inode = 1,
                .stripe = io->offset >> bsd->block_order,
@ -384,7 +368,7 @@ static int sec_invalidate(struct thread_data *td, struct fio_file *f)
 }
 struct ioengine_ops ioengine = {
-    .name               = "vitastor_secondary_osd",
+    .name               = "microceph_secondary_osd",
    .version            = FIO_IOOPS_VERSION,
    .flags              = FIO_MEMALIGN | FIO_DISKLESSIO | FIO_NOEXTEND,
    .setup              = sec_setup,
--- a/http_client.cpp
+++ b/http_client.cpp
@ -1,691 +0,0 @@
 // Copyright (c) Vitaliy Filippov, 2019+
 // License: VNPL-1.0 or GNU GPL-2.0+ (see README.md for details)
 #include <netinet/tcp.h>
 #include <sys/epoll.h>
 #include <net/if.h>
 #include <arpa/inet.h>
 #include <ifaddrs.h>
 #include <ctype.h>
 #include <unistd.h>
 #include <fcntl.h>
 #include <string.h>
 #include "json11/json11.hpp"
 #include "http_client.h"
 #include "timerfd_manager.h"
 #define READ_BUFFER_SIZE 9000
 static int extract_port(std::string & host);
 static std::string strtolower(const std::string & in);
 static std::string trim(const std::string & in);
 static std::string ws_format_frame(int type, uint64_t size);
 static bool ws_parse_frame(std::string & buf, int & type, std::string & res);
 // FIXME: Use keepalive
 struct http_co_t
 {
    timerfd_manager_t *tfd;
    int request_timeout = 0;
    std::string host;
    std::string request;
    std::string ws_outbox;
    std::string response;
    bool want_streaming;
    http_response_t parsed;
    uint64_t target_response_size = 0;
    int state = 0;
    int peer_fd = -1;
    int timeout_id = -1;
    int epoll_events = 0;
    int sent = 0;
    std::vector<char> rbuf;
    iovec read_iov, send_iov;
    msghdr read_msg = { 0 }, send_msg = { 0 };
    std::function<void(const http_response_t*)> callback;
    websocket_t ws;
    int onstack = 0;
    bool ended = false;
    ~http_co_t();
    inline void stackin() { onstack++; }
    inline void stackout() { onstack--; if (!onstack && ended) end(); }
    inline void end() { ended = true; if (!onstack) { delete this; } }
    void start_connection();
    void handle_events();
    void handle_connect_result();
    void submit_read();
    void submit_send();
    bool handle_read();
    void post_message(int type, const std::string & msg);
 };
 #define HTTP_CO_CONNECTING 1
 #define HTTP_CO_SENDING_REQUEST 2
 #define HTTP_CO_REQUEST_SENT 3
 #define HTTP_CO_HEADERS_RECEIVED 4
 #define HTTP_CO_WEBSOCKET 5
 #define HTTP_CO_CHUNKED 6
 #define DEFAULT_TIMEOUT 5000
 void http_request(timerfd_manager_t *tfd, const std::string & host, const std::string & request,
    const http_options_t & options, std::function<void(const http_response_t *response)> callback)
 {
    http_co_t *handler = new http_co_t();
    handler->request_timeout = options.timeout < 0 ? 0 : (options.timeout == 0 ? DEFAULT_TIMEOUT : options.timeout);
    handler->want_streaming = options.want_streaming;
    handler->tfd = tfd;
    handler->host = host;
    handler->request = request;
    handler->callback = callback;
    handler->ws.co = handler;
    handler->start_connection();
 }
 void http_request_json(timerfd_manager_t *tfd, const std::string & host, const std::string & request,
    int timeout, std::function<void(std::string, json11::Json r)> callback)
 {
    http_request(tfd, host, request, { .timeout = timeout }, [callback](const http_response_t* res)
    {
        if (res->error_code != 0)
        {
            callback("Error code: "+std::to_string(res->error_code)+" ("+std::string(strerror(res->error_code))+")", json11::Json());
            return;
        }
        if (res->status_code != 200)
        {
            callback("HTTP "+std::to_string(res->status_code)+" "+res->status_line+" body: "+trim(res->body), json11::Json());
            return;
        }
        std::string json_err;
        json11::Json data = json11::Json::parse(res->body, json_err);
        if (json_err != "")
        {
            callback("Bad JSON: "+json_err+" (response: "+trim(res->body)+")", json11::Json());
            return;
        }
        callback(std::string(), data);
    });
 }
 websocket_t* open_websocket(timerfd_manager_t *tfd, const std::string & host, const std::string & path,
    int timeout, std::function<void(const http_response_t *msg)> callback)
 {
    std::string request = "GET "+path+" HTTP/1.1\r\n"
        "Host: "+host+"\r\n"
        "Upgrade: websocket\r\n"
        "Connection: upgrade\r\n"
        "Sec-WebSocket-Key: x3JJHMbDL1EzLkh9GBhXDw==\r\n"
        "Sec-WebSocket-Version: 13\r\n"
        "\r\n";
    http_co_t *handler = new http_co_t();
    handler->request_timeout = timeout < 0 ? -1 : (timeout == 0 ? DEFAULT_TIMEOUT : timeout);
    handler->want_streaming = false;
    handler->tfd = tfd;
    handler->host = host;
    handler->request = request;
    handler->callback = callback;
    handler->ws.co = handler;
    handler->start_connection();
    return &handler->ws;
 }
 void websocket_t::post_message(int type, const std::string & msg)
 {
    co->post_message(type, msg);
 }
 void websocket_t::close()
 {
    co->end();
 }
 http_co_t::~http_co_t()
 {
    if (timeout_id >= 0)
    {
        tfd->clear_timer(timeout_id);
        timeout_id = -1;
    }
    if (peer_fd >= 0)
    {
        tfd->set_fd_handler(peer_fd, false, NULL);
        close(peer_fd);
        peer_fd = -1;
    }
    if (parsed.headers["transfer-encoding"] == "chunked")
    {
        int prev = 0, pos = 0;
        while ((pos = response.find("\r\n", prev)) >= prev)
        {
            uint64_t len = strtoull(response.c_str()+prev, NULL, 16);
            parsed.body += response.substr(pos+2, len);
            prev = pos+2+len+2;
        }
    }
    else
    {
        std::swap(parsed.body, response);
    }
    parsed.eof = true;
    callback(&parsed);
 }
 void http_co_t::start_connection()
 {
    stackin();
    int port = extract_port(host);
    struct sockaddr_in addr;
    int r;
    if ((r = inet_pton(AF_INET, host.c_str(), &addr.sin_addr)) != 1)
    {
        parsed.error_code = ENXIO;
        stackout();
        end();
        return;
    }
    addr.sin_family = AF_INET;
    addr.sin_port = htons(port ? port : 80);
    peer_fd = socket(AF_INET, SOCK_STREAM, 0);
    if (peer_fd < 0)
    {
        parsed.error_code = errno;
        stackout();
        end();
        return;
    }
    fcntl(peer_fd, F_SETFL, fcntl(peer_fd, F_GETFL, 0) | O_NONBLOCK);
    if (request_timeout > 0)
    {
        timeout_id = tfd->set_timer(request_timeout, false, [this](int timer_id)
        {
            if (response.length() == 0)
            {
                parsed.error_code = ETIME;
            }
            end();
        });
    }
    epoll_events = 0;
    // Finally call connect
    r = ::connect(peer_fd, (sockaddr*)&addr, sizeof(addr));
    if (r < 0 && errno != EINPROGRESS)
    {
        parsed.error_code = errno;
        stackout();
        end();
        return;
    }
    tfd->set_fd_handler(peer_fd, true, [this](int peer_fd, int epoll_events)
    {
        this->epoll_events |= epoll_events;
        handle_events();
    });
    state = HTTP_CO_CONNECTING;
    stackout();
 }
 void http_co_t::handle_events()
 {
    stackin();
    while (epoll_events)
    {
        if (state == HTTP_CO_CONNECTING)
        {
            handle_connect_result();
        }
        else
        {
            epoll_events &= ~EPOLLOUT;
            if (epoll_events & EPOLLIN)
            {
                submit_read();
            }
            else if (epoll_events & (EPOLLRDHUP|EPOLLERR))
            {
                end();
                break;
            }
        }
    }
    stackout();
 }
 void http_co_t::handle_connect_result()
 {
    stackin();
    int result = 0;
    socklen_t result_len = sizeof(result);
    if (getsockopt(peer_fd, SOL_SOCKET, SO_ERROR, &result, &result_len) < 0)
    {
        result = errno;
    }
    if (result != 0)
    {
        parsed.error_code = result;
        stackout();
        end();
        return;
    }
    int one = 1;
    setsockopt(peer_fd, SOL_TCP, TCP_NODELAY, &one, sizeof(one));
    tfd->set_fd_handler(peer_fd, false, [this](int peer_fd, int epoll_events)
    {
        this->epoll_events |= epoll_events;
        handle_events();
    });
    state = HTTP_CO_SENDING_REQUEST;
    submit_send();
    stackout();
 }
 void http_co_t::submit_read()
 {
    stackin();
    int res;
    if (rbuf.size() != READ_BUFFER_SIZE)
    {
        rbuf.resize(READ_BUFFER_SIZE);
    }
    read_iov = { .iov_base = rbuf.data(), .iov_len = READ_BUFFER_SIZE };
    read_msg.msg_iov = &read_iov;
    read_msg.msg_iovlen = 1;
    res = recvmsg(peer_fd, &read_msg, 0);
    if (res < 0)
    {
        res = -errno;
    }
    if (res == -EAGAIN)
    {
        epoll_events = epoll_events & ~EPOLLIN;
    }
    else if (res <= 0)
    {
        // < 0 means error, 0 means EOF
        if (!res)
            epoll_events = epoll_events & ~EPOLLIN;
        end();
    }
    else
    {
        response += std::string(rbuf.data(), res);
        handle_read();
    }
    stackout();
 }
 void http_co_t::submit_send()
 {
    stackin();
    int res;
 again:
    if (sent < request.size())
    {
        send_iov = (iovec){ .iov_base = (void*)(request.c_str()+sent), .iov_len = request.size()-sent };
        send_msg.msg_iov = &send_iov;
        send_msg.msg_iovlen = 1;
        res = sendmsg(peer_fd, &send_msg, MSG_NOSIGNAL);
        if (res < 0)
        {
            res = -errno;
        }
        if (res == -EAGAIN)
        {
            res = 0;
        }
        else if (res < 0)
        {
            stackout();
            end();
            return;
        }
        sent += res;
        if (state == HTTP_CO_SENDING_REQUEST)
        {
            if (sent >= request.size())
            {
                state = HTTP_CO_REQUEST_SENT;
            }
            else
                goto again;
        }
        else if (state == HTTP_CO_WEBSOCKET)
        {
            request = request.substr(sent);
            sent = 0;
            goto again;
        }
    }
    stackout();
 }
 bool http_co_t::handle_read()
 {
    stackin();
    if (state == HTTP_CO_REQUEST_SENT)
    {
        int pos = response.find("\r\n\r\n");
        if (pos >= 0)
        {
            if (timeout_id >= 0)
            {
                tfd->clear_timer(timeout_id);
                timeout_id = -1;
            }
            state = HTTP_CO_HEADERS_RECEIVED;
            parse_http_headers(response, &parsed);
            if (parsed.status_code == 101 &&
                parsed.headers.find("sec-websocket-accept") != parsed.headers.end() &&
                parsed.headers["upgrade"] == "websocket" &&
                parsed.headers["connection"] == "upgrade")
            {
                // Don't care about validating the key
                state = HTTP_CO_WEBSOCKET;
                request = ws_outbox;
                ws_outbox = "";
                sent = 0;
                submit_send();
            }
            else if (parsed.headers["transfer-encoding"] == "chunked")
            {
                state = HTTP_CO_CHUNKED;
            }
            else if (parsed.headers["connection"] != "close")
            {
                target_response_size = stoull_full(parsed.headers["content-length"]);
                if (!target_response_size)
                {
                    // Sorry, unsupported response
                    stackout();
                    end();
                    return false;
                }
            }
        }
    }
    if (state == HTTP_CO_HEADERS_RECEIVED && target_response_size > 0 && response.size() >= target_response_size)
    {
        stackout();
        end();
        return false;
    }
    if (state == HTTP_CO_CHUNKED && response.size() > 0)
    {
        int prev = 0, pos = 0;
        while ((pos = response.find("\r\n", prev)) >= prev)
        {
            uint64_t len = strtoull(response.c_str()+prev, NULL, 16);
            if (!len)
            {
                // Zero length chunk indicates EOF
                parsed.eof = true;
                break;
            }
            if (response.size() < pos+2+len+2)
            {
                break;
            }
            parsed.body += response.substr(pos+2, len);
            prev = pos+2+len+2;
        }
        if (prev > 0)
        {
            response = response.substr(prev);
        }
        if (parsed.eof)
        {
            stackout();
            end();
            return false;
        }
        if (want_streaming && parsed.body.size() > 0)
        {
            callback(&parsed);
            parsed.body = "";
        }
    }
    if (state == HTTP_CO_WEBSOCKET && response.size() > 0)
    {
        while (ws_parse_frame(response, parsed.ws_msg_type, parsed.body))
        {
            callback(&parsed);
            parsed.body = "";
        }
    }
    stackout();
    return true;
 }
 void http_co_t::post_message(int type, const std::string & msg)
 {
    stackin();
    if (state == HTTP_CO_WEBSOCKET)
    {
        request += ws_format_frame(type, msg.size());
        request += msg;
        submit_send();
    }
    else
    {
        ws_outbox += ws_format_frame(type, msg.size());
        ws_outbox += msg;
    }
    stackout();
 }
 uint64_t stoull_full(const std::string & str, int base)
 {
    if (isspace(str[0]))
    {
        return 0;
    }
    char *end = NULL;
    uint64_t r = strtoull(str.c_str(), &end, base);
    if (end != str.c_str()+str.length())
    {
        return 0;
    }
    return r;
 }
 void parse_http_headers(std::string & res, http_response_t *parsed)
 {
    int pos = res.find("\r\n");
    pos = pos < 0 ? res.length() : pos+2;
    std::string status_line = res.substr(0, pos);
    int http_version;
    char *status_text = NULL;
    sscanf(status_line.c_str(), "HTTP/1.%d %d %ms", &http_version, &parsed->status_code, &status_text);
    if (status_text)
    {
        parsed->status_line = status_text;
        // %ms = allocate a buffer
        free(status_text);
        status_text = NULL;
    }
    int prev = pos;
    while ((pos = res.find("\r\n", prev)) >= prev)
    {
        if (pos == prev)
        {
            res = res.substr(pos+2);
            break;
        }
        std::string header = res.substr(prev, pos-prev);
        int p2 = header.find(":");
        if (p2 >= 0)
        {
            std::string key = strtolower(header.substr(0, p2));
            int p3 = p2+1;
            while (p3 < header.length() && isblank(header[p3]))
                p3++;
            parsed->headers[key] = key == "connection" || key == "upgrade" || key == "transfer-encoding"
                ? strtolower(header.substr(p3)) : header.substr(p3);
        }
        prev = pos+2;
    }
 }
 static std::string ws_format_frame(int type, uint64_t size)
 {
    // Always zero mask
    std::string res;
    int p = 0;
    res.resize(2 + (size >= 126 ? 2 : 0) + (size >= 65536 ? 6 : 0) + /*mask*/4);
    res[p++] = 0x80 | type;
    if (size < 126)
        res[p++] = size | /*mask*/0x80;
    else if (size < 65536)
    {
        res[p++] = 126 | /*mask*/0x80;
        res[p++] = (size >> 8) & 0xFF;
        res[p++] = (size >> 0) & 0xFF;
    }
    else
    {
        res[p++] = 127 | /*mask*/0x80;
        res[p++] = (size >> 56) & 0xFF;
        res[p++] = (size >> 48) & 0xFF;
        res[p++] = (size >> 40) & 0xFF;
        res[p++] = (size >> 32) & 0xFF;
        res[p++] = (size >> 24) & 0xFF;
        res[p++] = (size >> 16) & 0xFF;
        res[p++] = (size >>  8) & 0xFF;
        res[p++] = (size >>  0) & 0xFF;
    }
    res[p++] = 0;
    res[p++] = 0;
    res[p++] = 0;
    res[p++] = 0;
    return res;
 }
 static bool ws_parse_frame(std::string & buf, int & type, std::string & res)
 {
    uint64_t hdr = 2;
    if (buf.size() < hdr)
    {
        return false;
    }
    type = buf[0] & ~0x80;
    bool mask = !!(buf[1] & 0x80);
    hdr += mask ? 4 : 0;
    uint64_t len = ((uint8_t)buf[1] & ~0x80);
    if (len == 126)
    {
        hdr += 2;
        if (buf.size() < hdr)
        {
            return false;
        }
        len = ((uint64_t)(uint8_t)buf[2] << 8) | ((uint64_t)(uint8_t)buf[3] << 0);
    }
    else if (len == 127)
    {
        hdr += 8;
        if (buf.size() < hdr)
        {
            return false;
        }
        len = ((uint64_t)(uint8_t)buf[2] << 56) |
            ((uint64_t)(uint8_t)buf[3] << 48) |
            ((uint64_t)(uint8_t)buf[4] << 40) |
            ((uint64_t)(uint8_t)buf[5] << 32) |
            ((uint64_t)(uint8_t)buf[6] << 24) |
            ((uint64_t)(uint8_t)buf[7] << 16) |
            ((uint64_t)(uint8_t)buf[8] << 8) |
            ((uint64_t)(uint8_t)buf[9] << 0);
    }
    if (buf.size() < hdr+len)
    {
        return false;
    }
    if (mask)
    {
        for (int i = 0; i < len; i++)
            buf[hdr+i] ^= buf[hdr-4+(i & 3)];
    }
    res += buf.substr(hdr, len);
    buf = buf.substr(hdr+len);
    return true;
 }
 std::vector<std::string> getifaddr_list(bool include_v6)
 {
    std::vector<std::string> addresses;
    ifaddrs *list, *ifa;
    if (getifaddrs(&list) == -1)
    {
        throw std::runtime_error(std::string("getifaddrs: ") + strerror(errno));
    }
    for (ifa = list; ifa != NULL; ifa = ifa->ifa_next)
    {
        if (!ifa->ifa_addr)
        {
            continue;
        }
        int family = ifa->ifa_addr->sa_family;
        if ((family == AF_INET || family == AF_INET6 && include_v6) &&
            (ifa->ifa_flags & (IFF_UP | IFF_RUNNING | IFF_LOOPBACK)) == (IFF_UP | IFF_RUNNING))
        {
            void *addr_ptr;
            if (family == AF_INET)
                addr_ptr = &((sockaddr_in *)ifa->ifa_addr)->sin_addr;
            else
                addr_ptr = &((sockaddr_in6 *)ifa->ifa_addr)->sin6_addr;
            char addr[INET6_ADDRSTRLEN];
            if (!inet_ntop(family, addr_ptr, addr, INET6_ADDRSTRLEN))
            {
                throw std::runtime_error(std::string("inet_ntop: ") + strerror(errno));
            }
            addresses.push_back(std::string(addr));
        }
    }
    freeifaddrs(list);
    return addresses;
 }
 static int extract_port(std::string & host)
 {
    int port = 0;
    int pos = 0;
    if ((pos = host.find(':')) >= 0)
    {
        port = strtoull(host.c_str() + pos + 1, NULL, 10);
        if (port >= 0x10000)
        {
            port = 0;
        }
        host = host.substr(0, pos);
    }
    return port;
 }
 static std::string strtolower(const std::string & in)
 {
    std::string s = in;
    for (int i = 0; i < s.length(); i++)
    {
        s[i] = tolower(s[i]);
    }
    return s;
 }
 static std::string trim(const std::string & in)
 {
    int begin = in.find_first_not_of(" \n\r\t");
    if (begin == -1)
        return "";
    int end = in.find_last_not_of(" \n\r\t");
    return in.substr(begin, end+1-begin);
 }
--- a/http_client.h
+++ b/http_client.h
@ -1,59 +0,0 @@
 // Copyright (c) Vitaliy Filippov, 2019+
 // License: VNPL-1.0 or GNU GPL-2.0+ (see README.md for details)
 #pragma once
 #include <string>
 #include <vector>
 #include <map>
 #include <functional>
 #include "json11/json11.hpp"
 #define WS_CONTINUATION 0
 #define WS_TEXT 1
 #define WS_BINARY 2
 #define WS_CLOSE 8
 #define WS_PING 9
 #define WS_PONG 10
 class timerfd_manager_t;
 struct http_options_t
 {
    int timeout;
    bool want_streaming;
 };
 struct http_response_t
 {
    bool eof = false;
    int error_code = 0;
    int status_code = 0;
    std::string status_line;
    std::map<std::string, std::string> headers;
    int ws_msg_type = -1;
    std::string body;
 };
 struct http_co_t;
 struct websocket_t
 {
    http_co_t *co;
    void post_message(int type, const std::string & msg);
    void close();
 };
 void parse_http_headers(std::string & res, http_response_t *parsed);
 std::vector<std::string> getifaddr_list(bool include_v6 = false);
 uint64_t stoull_full(const std::string & str, int base = 10);
 void http_request(timerfd_manager_t *tfd, const std::string & host, const std::string & request,
    const http_options_t & options, std::function<void(const http_response_t *response)> callback);
 void http_request_json(timerfd_manager_t *tfd, const std::string & host, const std::string & request,
    int timeout, std::function<void(std::string, json11::Json r)> callback);
 websocket_t* open_websocket(timerfd_manager_t *tfd, const std::string & host, const std::string & path,
    int timeout, std::function<void(const http_response_t *msg)> callback);
--- a/1
+++ b/1
@ -1 +0,0 @@
 Subproject commit 97f06cb20c1e136fd37d58fb40f57dd8f8a3a4a7
--- a/lambda_size.cpp
+++ b/lambda_size.cpp
@ -1,6 +1,3 @@
 // Copyright (c) Vitaliy Filippov, 2019+
 // License: VNPL-1.0 (see README.md for details)
 #include <iostream>
 #include <functional>
 #include <array>
--- a/malloc_or_die.h
+++ b/malloc_or_die.h
@ -1,50 +0,0 @@
 // Copyright (c) Vitaliy Filippov, 2019+
 // License: VNPL-1.0 or GNU GPL-2.0+ (see README.md for details)
 #pragma once
 #include <malloc.h>
 inline void* memalign_or_die(size_t alignment, size_t size)
 {
    void *buf = memalign(alignment, size);
    if (!buf)
    {
        printf("Failed to allocate %lu bytes\n", size);
        exit(1);
    }
    return buf;
 }
 inline void* malloc_or_die(size_t size)
 {
    void *buf = malloc(size);
    if (!buf)
    {
        printf("Failed to allocate %lu bytes\n", size);
        exit(1);
    }
    return buf;
 }
 inline void* realloc_or_die(void *ptr, size_t size)
 {
    void *buf = realloc(ptr, size);
    if (!buf)
    {
        printf("Failed to allocate %lu bytes\n", size);
        exit(1);
    }
    return buf;
 }
 inline void* calloc_or_die(size_t nmemb, size_t size)
 {
    void *buf = calloc(nmemb, size);
    if (!buf)
    {
        printf("Failed to allocate %lu bytes\n", size * nmemb);
        exit(1);
    }
    return buf;
 }
--- a/messenger.cpp
+++ b/messenger.cpp
@ -1,412 +0,0 @@
 // Copyright (c) Vitaliy Filippov, 2019+
 // License: VNPL-1.0 or GNU GPL-2.0+ (see README.md for details)
 #include <unistd.h>
 #include <fcntl.h>
 #include <sys/socket.h>
 #include <sys/epoll.h>
 #include <netinet/tcp.h>
 #include "messenger.h"
 osd_op_t::~osd_op_t()
 {
    assert(!bs_op);
    assert(!op_data);
    if (rmw_buf)
    {
        free(rmw_buf);
    }
    if (buf)
    {
        // Note: reusing osd_op_t WILL currently lead to memory leaks
        // So we don't reuse it, but free it every time
        free(buf);
    }
 }
 osd_messenger_t::~osd_messenger_t()
 {
    while (clients.size() > 0)
    {
        stop_client(clients.begin()->first);
    }
 }
 void osd_messenger_t::connect_peer(uint64_t peer_osd, json11::Json peer_state)
 {
    if (wanted_peers.find(peer_osd) == wanted_peers.end())
    {
        wanted_peers[peer_osd] = (osd_wanted_peer_t){
            .address_list = peer_state["addresses"],
            .port = (int)peer_state["port"].int64_value(),
        };
    }
    else
    {
        wanted_peers[peer_osd].address_list = peer_state["addresses"];
        wanted_peers[peer_osd].port = (int)peer_state["port"].int64_value();
    }
    wanted_peers[peer_osd].address_changed = true;
    if (!wanted_peers[peer_osd].connecting &&
        (time(NULL) - wanted_peers[peer_osd].last_connect_attempt) >= peer_connect_interval)
    {
        try_connect_peer(peer_osd);
    }
 }
 void osd_messenger_t::try_connect_peer(uint64_t peer_osd)
 {
    auto wp_it = wanted_peers.find(peer_osd);
    if (wp_it == wanted_peers.end())
    {
        return;
    }
    if (osd_peer_fds.find(peer_osd) != osd_peer_fds.end())
    {
        wanted_peers.erase(peer_osd);
        return;
    }
    auto & wp = wp_it->second;
    if (wp.address_index >= wp.address_list.array_items().size())
    {
        return;
    }
    wp.cur_addr = wp.address_list[wp.address_index].string_value();
    wp.cur_port = wp.port;
    wp.connecting = true;
    try_connect_peer_addr(peer_osd, wp.cur_addr.c_str(), wp.cur_port);
 }
 void osd_messenger_t::try_connect_peer_addr(osd_num_t peer_osd, const char *peer_host, int peer_port)
 {
    struct sockaddr_in addr;
    int r;
    if ((r = inet_pton(AF_INET, peer_host, &addr.sin_addr)) != 1)
    {
        on_connect_peer(peer_osd, -EINVAL);
        return;
    }
    addr.sin_family = AF_INET;
    addr.sin_port = htons(peer_port ? peer_port : 11203);
    int peer_fd = socket(AF_INET, SOCK_STREAM, 0);
    if (peer_fd < 0)
    {
        on_connect_peer(peer_osd, -errno);
        return;
    }
    fcntl(peer_fd, F_SETFL, fcntl(peer_fd, F_GETFL, 0) | O_NONBLOCK);
    int timeout_id = -1;
    if (peer_connect_timeout > 0)
    {
        timeout_id = tfd->set_timer(1000*peer_connect_timeout, false, [this, peer_fd](int timer_id)
        {
            osd_num_t peer_osd = clients[peer_fd].osd_num;
            stop_client(peer_fd);
            on_connect_peer(peer_osd, -EIO);
            return;
        });
    }
    r = connect(peer_fd, (sockaddr*)&addr, sizeof(addr));
    if (r < 0 && errno != EINPROGRESS)
    {
        close(peer_fd);
        on_connect_peer(peer_osd, -errno);
        return;
    }
    assert(peer_osd != this->osd_num);
    clients[peer_fd] = (osd_client_t){
        .peer_addr = addr,
        .peer_port = peer_port,
        .peer_fd = peer_fd,
        .peer_state = PEER_CONNECTING,
        .connect_timeout_id = timeout_id,
        .osd_num = peer_osd,
        .in_buf = malloc_or_die(receive_buffer_size),
    };
    tfd->set_fd_handler(peer_fd, true, [this](int peer_fd, int epoll_events)
    {
        // Either OUT (connected) or HUP
        handle_connect_epoll(peer_fd);
    });
 }
 void osd_messenger_t::handle_connect_epoll(int peer_fd)
 {
    auto & cl = clients[peer_fd];
    if (cl.connect_timeout_id >= 0)
    {
        tfd->clear_timer(cl.connect_timeout_id);
        cl.connect_timeout_id = -1;
    }
    osd_num_t peer_osd = cl.osd_num;
    int result = 0;
    socklen_t result_len = sizeof(result);
    if (getsockopt(peer_fd, SOL_SOCKET, SO_ERROR, &result, &result_len) < 0)
    {
        result = errno;
    }
    if (result != 0)
    {
        stop_client(peer_fd);
        on_connect_peer(peer_osd, -result);
        return;
    }
    int one = 1;
    setsockopt(peer_fd, SOL_TCP, TCP_NODELAY, &one, sizeof(one));
    cl.peer_state = PEER_CONNECTED;
    tfd->set_fd_handler(peer_fd, false, [this](int peer_fd, int epoll_events)
    {
        handle_peer_epoll(peer_fd, epoll_events);
    });
    // Check OSD number
    check_peer_config(cl);
 }
 void osd_messenger_t::handle_peer_epoll(int peer_fd, int epoll_events)
 {
    // Mark client as ready (i.e. some data is available)
    if (epoll_events & EPOLLRDHUP)
    {
        // Stop client
        printf("[OSD %lu] client %d disconnected\n", this->osd_num, peer_fd);
        stop_client(peer_fd);
    }
    else if (epoll_events & EPOLLIN)
    {
        // Mark client as ready (i.e. some data is available)
        auto & cl = clients[peer_fd];
        cl.read_ready++;
        if (cl.read_ready == 1)
        {
            read_ready_clients.push_back(cl.peer_fd);
            if (ringloop)
                ringloop->wakeup();
            else
                read_requests();
        }
    }
 }
 void osd_messenger_t::on_connect_peer(osd_num_t peer_osd, int peer_fd)
 {
    auto & wp = wanted_peers.at(peer_osd);
    wp.connecting = false;
    if (peer_fd < 0)
    {
        printf("Failed to connect to peer OSD %lu address %s port %d: %s\n", peer_osd, wp.cur_addr.c_str(), wp.cur_port, strerror(-peer_fd));
        if (wp.address_changed)
        {
            wp.address_changed = false;
            wp.address_index = 0;
            try_connect_peer(peer_osd);
        }
        else if (wp.address_index < wp.address_list.array_items().size()-1)
        {
            // Try other addresses
            wp.address_index++;
            try_connect_peer(peer_osd);
        }
        else
        {
            // Retry again in <peer_connect_interval> seconds
            wp.last_connect_attempt = time(NULL);
            wp.address_index = 0;
            tfd->set_timer(1000*peer_connect_interval, false, [this, peer_osd](int)
            {
                try_connect_peer(peer_osd);
            });
        }
        return;
    }
    printf("Connected with peer OSD %lu (fd %d)\n", peer_osd, peer_fd);
    wanted_peers.erase(peer_osd);
    repeer_pgs(peer_osd);
 }
 void osd_messenger_t::check_peer_config(osd_client_t & cl)
 {
    osd_op_t *op = new osd_op_t();
    op->op_type = OSD_OP_OUT;
    op->peer_fd = cl.peer_fd;
    op->req = {
        .show_conf = {
            .header = {
                .magic = SECONDARY_OSD_OP_MAGIC,
                .id = this->next_subop_id++,
                .opcode = OSD_OP_SHOW_CONFIG,
            },
        },
    };
    op->callback = [this](osd_op_t *op)
    {
        osd_client_t & cl = clients[op->peer_fd];
        std::string json_err;
        json11::Json config;
        bool err = false;
        if (op->reply.hdr.retval < 0)
        {
            err = true;
            printf("Failed to get config from OSD %lu (retval=%ld), disconnecting peer\n", cl.osd_num, op->reply.hdr.retval);
        }
        else
        {
            config = json11::Json::parse(std::string((char*)op->buf), json_err);
            if (json_err != "")
            {
                err = true;
                printf("Failed to get config from OSD %lu: bad JSON: %s, disconnecting peer\n", cl.osd_num, json_err.c_str());
            }
            else if (config["osd_num"].uint64_value() != cl.osd_num)
            {
                err = true;
                printf("Connected to OSD %lu instead of OSD %lu, peer state is outdated, disconnecting peer\n", config["osd_num"].uint64_value(), cl.osd_num);
            }
        }
        if (err)
        {
            osd_num_t osd_num = cl.osd_num;
            stop_client(op->peer_fd);
            on_connect_peer(osd_num, -1);
            delete op;
            return;
        }
        osd_peer_fds[cl.osd_num] = cl.peer_fd;
        on_connect_peer(cl.osd_num, cl.peer_fd);
        delete op;
    };
    outbox_push(op);
 }
 void osd_messenger_t::cancel_osd_ops(osd_client_t & cl)
 {
    for (auto p: cl.sent_ops)
    {
        cancel_op(p.second);
    }
    cl.sent_ops.clear();
    for (auto op: cl.outbox)
    {
        cancel_op(op);
    }
    cl.outbox.clear();
    if (cl.write_op)
    {
        cancel_op(cl.write_op);
        cl.write_op = NULL;
    }
 }
 void osd_messenger_t::cancel_op(osd_op_t *op)
 {
    if (op->op_type == OSD_OP_OUT)
    {
        op->reply.hdr.magic = SECONDARY_OSD_REPLY_MAGIC;
        op->reply.hdr.id = op->req.hdr.id;
        op->reply.hdr.opcode = op->req.hdr.opcode;
        op->reply.hdr.retval = -EPIPE;
        // Copy lambda to be unaffected by `delete op`
        std::function<void(osd_op_t*)>(op->callback)(op);
    }
    else
    {
        // This function is only called in stop_client(), so it's fine to destroy the operation
        delete op;
    }
 }
 void osd_messenger_t::stop_client(int peer_fd)
 {
    assert(peer_fd != 0);
    auto it = clients.find(peer_fd);
    if (it == clients.end())
    {
        return;
    }
    uint64_t repeer_osd = 0;
    osd_client_t cl = it->second;
    if (cl.peer_state == PEER_CONNECTED)
    {
        if (cl.osd_num)
        {
            // Reload configuration from etcd when the connection is dropped
            printf("[OSD %lu] Stopping client %d (OSD peer %lu)\n", osd_num, peer_fd, cl.osd_num);
            repeer_osd = cl.osd_num;
        }
        else
        {
            printf("[OSD %lu] Stopping client %d (regular client)\n", osd_num, peer_fd);
        }
    }
    clients.erase(it);
    tfd->set_fd_handler(peer_fd, false, NULL);
    if (cl.osd_num)
    {
        osd_peer_fds.erase(cl.osd_num);
        // Cancel outbound operations
        cancel_osd_ops(cl);
    }
    if (cl.read_op)
    {
        delete cl.read_op;
        cl.read_op = NULL;
    }
    for (auto rit = read_ready_clients.begin(); rit != read_ready_clients.end(); rit++)
    {
        if (*rit == peer_fd)
        {
            read_ready_clients.erase(rit);
            break;
        }
    }
    for (auto wit = write_ready_clients.begin(); wit != write_ready_clients.end(); wit++)
    {
        if (*wit == peer_fd)
        {
            write_ready_clients.erase(wit);
            break;
        }
    }
    free(cl.in_buf);
    close(peer_fd);
    if (repeer_osd)
    {
        repeer_pgs(repeer_osd);
    }
 }
 void osd_messenger_t::accept_connections(int listen_fd)
 {
    // Accept new connections
    sockaddr_in addr;
    socklen_t peer_addr_size = sizeof(addr);
    int peer_fd;
    while ((peer_fd = accept(listen_fd, (sockaddr*)&addr, &peer_addr_size)) >= 0)
    {
        assert(peer_fd != 0);
        char peer_str[256];
        printf("[OSD %lu] new client %d: connection from %s port %d\n", this->osd_num, peer_fd,
            inet_ntop(AF_INET, &addr.sin_addr, peer_str, 256), ntohs(addr.sin_port));
        fcntl(peer_fd, F_SETFL, fcntl(peer_fd, F_GETFL, 0) | O_NONBLOCK);
        int one = 1;
        setsockopt(peer_fd, SOL_TCP, TCP_NODELAY, &one, sizeof(one));
        clients[peer_fd] = {
            .peer_addr = addr,
            .peer_port = ntohs(addr.sin_port),
            .peer_fd = peer_fd,
            .peer_state = PEER_CONNECTED,
            .in_buf = malloc_or_die(receive_buffer_size),
        };
        // Add FD to epoll
        tfd->set_fd_handler(peer_fd, false, [this](int peer_fd, int epoll_events)
        {
            handle_peer_epoll(peer_fd, epoll_events);
        });
        // Try to accept next connection
        peer_addr_size = sizeof(addr);
    }
    if (peer_fd == -1 && errno != EAGAIN)
    {
        throw std::runtime_error(std::string("accept: ") + strerror(errno));
    }
 }
--- a/messenger.h
+++ b/messenger.h
@ -1,303 +0,0 @@
 // Copyright (c) Vitaliy Filippov, 2019+
 // License: VNPL-1.0 or GNU GPL-2.0+ (see README.md for details)
 #pragma once
 #include <sys/types.h>
 #include <stdint.h>
 #include <arpa/inet.h>
 #include <set>
 #include <map>
 #include <deque>
 #include <vector>
 #include "malloc_or_die.h"
 #include "json11/json11.hpp"
 #include "osd_ops.h"
 #include "timerfd_manager.h"
 #include "ringloop.h"
 #define OSD_OP_IN 0
 #define OSD_OP_OUT 1
 #define CL_READ_HDR 1
 #define CL_READ_DATA 2
 #define CL_READ_REPLY_DATA 3
 #define CL_WRITE_READY 1
 #define CL_WRITE_REPLY 2
 #define OSD_OP_INLINE_BUF_COUNT 16
 #define PEER_CONNECTING 1
 #define PEER_CONNECTED 2
 #define DEFAULT_PEER_CONNECT_INTERVAL 5
 #define DEFAULT_PEER_CONNECT_TIMEOUT 5
 // Kind of a vector with small-list-optimisation
 struct osd_op_buf_list_t
 {
    int count = 0, alloc = OSD_OP_INLINE_BUF_COUNT, done = 0;
    iovec *buf = NULL;
    iovec inline_buf[OSD_OP_INLINE_BUF_COUNT];
    inline osd_op_buf_list_t()
    {
        buf = inline_buf;
    }
    inline osd_op_buf_list_t(const osd_op_buf_list_t & other)
    {
        buf = inline_buf;
        append(other);
    }
    inline osd_op_buf_list_t & operator = (const osd_op_buf_list_t & other)
    {
        reset();
        append(other);
        return *this;
    }
    inline ~osd_op_buf_list_t()
    {
        if (buf && buf != inline_buf)
        {
            free(buf);
        }
    }
    inline void reset()
    {
        count = 0;
        done = 0;
    }
    inline iovec* get_iovec()
    {
        return buf + done;
    }
    inline int get_size()
    {
        return count - done;
    }
    inline void append(const osd_op_buf_list_t & other)
    {
        if (count+other.count > alloc)
        {
            if (buf == inline_buf)
            {
                int old = alloc;
                alloc = (((count+other.count+15)/16)*16);
                buf = (iovec*)malloc(sizeof(iovec) * alloc);
                if (!buf)
                {
                    printf("Failed to allocate %lu bytes\n", sizeof(iovec) * alloc);
                    exit(1);
                }
                memcpy(buf, inline_buf, sizeof(iovec) * old);
            }
            else
            {
                alloc = (((count+other.count+15)/16)*16);
                buf = (iovec*)realloc(buf, sizeof(iovec) * alloc);
                if (!buf)
                {
                    printf("Failed to allocate %lu bytes\n", sizeof(iovec) * alloc);
                    exit(1);
                }
            }
        }
        for (int i = 0; i < other.count; i++)
        {
            buf[count++] = other.buf[i];
        }
    }
    inline void push_back(void *nbuf, size_t len)
    {
        if (count >= alloc)
        {
            if (buf == inline_buf)
            {
                int old = alloc;
                alloc = ((alloc/16)*16 + 1);
                buf = (iovec*)malloc(sizeof(iovec) * alloc);
                if (!buf)
                {
                    printf("Failed to allocate %lu bytes\n", sizeof(iovec) * alloc);
                    exit(1);
                }
                memcpy(buf, inline_buf, sizeof(iovec)*old);
            }
            else
            {
                alloc = alloc < 16 ? 16 : (alloc+16);
                buf = (iovec*)realloc(buf, sizeof(iovec) * alloc);
                if (!buf)
                {
                    printf("Failed to allocate %lu bytes\n", sizeof(iovec) * alloc);
                    exit(1);
                }
            }
        }
        buf[count++] = { .iov_base = nbuf, .iov_len = len };
    }
    inline void eat(int result)
    {
        while (result > 0 && done < count)
        {
            iovec & iov = buf[done];
            if (iov.iov_len <= result)
            {
                result -= iov.iov_len;
                done++;
            }
            else
            {
                iov.iov_len -= result;
                iov.iov_base += result;
                break;
            }
        }
    }
 };
 struct blockstore_op_t;
 struct osd_primary_op_data_t;
 struct osd_op_t
 {
    timespec tv_begin;
    uint64_t op_type = OSD_OP_IN;
    int peer_fd;
    osd_any_op_t req;
    osd_any_reply_t reply;
    blockstore_op_t *bs_op = NULL;
    void *buf = NULL;
    void *rmw_buf = NULL;
    osd_primary_op_data_t* op_data = NULL;
    std::function<void(osd_op_t*)> callback;
    osd_op_buf_list_t iov;
    ~osd_op_t();
 };
 struct osd_client_t
 {
    sockaddr_in peer_addr;
    int peer_port;
    int peer_fd;
    int peer_state;
    int connect_timeout_id = -1;
    osd_num_t osd_num = 0;
    void *in_buf = NULL;
    // Read state
    int read_ready = 0;
    osd_op_t *read_op = NULL;
    iovec read_iov;
    msghdr read_msg;
    int read_remaining = 0;
    int read_state = 0;
    osd_op_buf_list_t recv_list;
    // Incoming operations
    std::vector<osd_op_t*> received_ops;
    // Outbound operations
    std::deque<osd_op_t*> outbox;
    std::map<int, osd_op_t*> sent_ops;
    // PGs dirtied by this client's primary-writes
    std::set<pool_pg_num_t> dirty_pgs;
    // Write state
    osd_op_t *write_op = NULL;
    msghdr write_msg;
    int write_state = 0;
    osd_op_buf_list_t send_list;
 };
 struct osd_wanted_peer_t
 {
    json11::Json address_list;
    int port;
    time_t last_connect_attempt;
    bool connecting, address_changed;
    int address_index;
    std::string cur_addr;
    int cur_port;
 };
 struct osd_op_stats_t
 {
    uint64_t op_stat_sum[OSD_OP_MAX+1] = { 0 };
    uint64_t op_stat_count[OSD_OP_MAX+1] = { 0 };
    uint64_t op_stat_bytes[OSD_OP_MAX+1] = { 0 };
    uint64_t subop_stat_sum[OSD_OP_MAX+1] = { 0 };
    uint64_t subop_stat_count[OSD_OP_MAX+1] = { 0 };
 };
 struct osd_messenger_t
 {
    timerfd_manager_t *tfd;
    ring_loop_t *ringloop;
    // osd_num_t is only for logging and asserts
    osd_num_t osd_num;
    // FIXME: make receive_buffer_size configurable
    int receive_buffer_size = 64*1024;
    int peer_connect_interval = DEFAULT_PEER_CONNECT_INTERVAL;
    int peer_connect_timeout = DEFAULT_PEER_CONNECT_TIMEOUT;
    int log_level = 0;
    bool use_sync_send_recv = false;
    std::map<osd_num_t, osd_wanted_peer_t> wanted_peers;
    std::map<uint64_t, int> osd_peer_fds;
    uint64_t next_subop_id = 1;
    std::map<int, osd_client_t> clients;
    std::vector<int> read_ready_clients;
    std::vector<int> write_ready_clients;
    std::vector<std::function<void()>> set_immediate;
    // op statistics
    osd_op_stats_t stats;
 public:
    void connect_peer(uint64_t osd_num, json11::Json peer_state);
    void stop_client(int peer_fd);
    void outbox_push(osd_op_t *cur_op);
    std::function<void(osd_op_t*)> exec_op;
    std::function<void(osd_num_t)> repeer_pgs;
    void handle_peer_epoll(int peer_fd, int epoll_events);
    void read_requests();
    void send_replies();
    void accept_connections(int listen_fd);
    ~osd_messenger_t();
 protected:
    void try_connect_peer(uint64_t osd_num);
    void try_connect_peer_addr(osd_num_t peer_osd, const char *peer_host, int peer_port);
    void handle_connect_epoll(int peer_fd);
    void on_connect_peer(osd_num_t peer_osd, int peer_fd);
    void check_peer_config(osd_client_t & cl);
    void cancel_osd_ops(osd_client_t & cl);
    void cancel_op(osd_op_t *op);
    bool try_send(osd_client_t & cl);
    void handle_send(int result, int peer_fd);
    bool handle_read(int result, int peer_fd);
    bool handle_finished_read(osd_client_t & cl);
    void handle_op_hdr(osd_client_t *cl);
    bool handle_reply_hdr(osd_client_t *cl);
    void handle_reply_ready(osd_op_t *op);
 };
--- a/mon/PGUtil.js
+++ b/mon/PGUtil.js
@ -1,112 +0,0 @@
 // Copyright (c) Vitaliy Filippov, 2019+
 // License: VNPL-1.0 (see README.md for details)
 module.exports = {
    scale_pg_count,
 };
 function scale_pg_count(prev_pgs, prev_pg_history, new_pg_history, new_pg_count)
 {
    const old_pg_count = prev_pgs.length;
    // Add all possibly intersecting PGs into the history of new PGs
    if (!(new_pg_count % old_pg_count))
    {
        // New PG count is a multiple of the old PG count
        const mul = (new_pg_count / old_pg_count);
        for (let i = 0; i < new_pg_count; i++)
        {
            const old_i = Math.floor(new_pg_count / mul);
            new_pg_history[i] = JSON.parse(JSON.stringify(prev_pg_history[1+old_i]));
        }
    }
    else if (!(old_pg_count % new_pg_count))
    {
        // Old PG count is a multiple of the new PG count
        const mul = (old_pg_count / new_pg_count);
        for (let i = 0; i < new_pg_count; i++)
        {
            new_pg_history[i] = {
                osd_sets: [],
                all_peers: [],
                epoch: 0,
            };
            for (let j = 0; j < mul; j++)
            {
                new_pg_history[i].osd_sets.push(prev_pgs[i*mul]);
                const hist = prev_pg_history[1+i*mul+j];
                if (hist && hist.osd_sets && hist.osd_sets.length)
                {
                    Array.prototype.push.apply(new_pg_history[i].osd_sets, hist.osd_sets);
                }
                if (hist && hist.all_peers && hist.all_peers.length)
                {
                    Array.prototype.push.apply(new_pg_history[i].all_peers, hist.all_peers);
                }
                if (hist && hist.epoch)
                {
                    new_pg_history[i].epoch = new_pg_history[i].epoch < hist.epoch ? hist.epoch : new_pg_history[i].epoch;
                }
            }
        }
    }
    else
    {
        // Any PG may intersect with any PG after non-multiple PG count change
        // So, merge ALL PGs history
        let all_sets = {};
        let all_peers = {};
        let max_epoch = 0;
        for (const pg of prev_pgs)
        {
            all_sets[pg.join(' ')] = pg;
        }
        for (const pg in prev_pg_history)
        {
            const hist = prev_pg_history[pg];
            if (hist && hist.osd_sets)
            {
                for (const pg of hist.osd_sets)
                {
                    all_sets[pg.join(' ')] = pg;
                }
            }
            if (hist && hist.all_peers)
            {
                for (const osd_num of hist.all_peers)
                {
                    all_peers[osd_num] = Number(osd_num);
                }
            }
            if (hist && hist.epoch)
            {
                max_epoch = max_epoch < hist.epoch ? hist.epoch : max_epoch;
            }
        }
        all_sets = Object.values(all_sets);
        all_peers = Object.values(all_peers);
        for (let i = 0; i < new_pg_count; i++)
        {
            new_pg_history[i] = { osd_sets: all_sets, all_peers, epoch: max_epoch };
        }
    }
    // Mark history keys for removed PGs as removed
    for (let i = new_pg_count; i < old_pg_count; i++)
    {
        new_pg_history[i] = null;
    }
    if (old_pg_count < new_pg_count)
    {
        for (let i = new_pg_count-1; i >= 0; i--)
        {
            prev_pgs[i] = prev_pgs[Math.floor(i/new_pg_count*old_pg_count)];
        }
    }
    else if (old_pg_count > new_pg_count)
    {
        for (let i = 0; i < new_pg_count; i++)
        {
            prev_pgs[i] = prev_pgs[Math.round(i/new_pg_count*old_pg_count)];
        }
        prev_pgs.splice(new_pg_count, old_pg_count-new_pg_count);
    }
 }
--- a/mon/afr.js
+++ b/mon/afr.js
@ -1,159 +0,0 @@
 // Functions to calculate Annualized Failure Rate of your cluster
 // if you know AFR of your drives, number of drives, expected rebalance time
 // and replication factor
 // License: VNPL-1.0 (see README.md for details)
 const { sprintf } = require('sprintf-js');
 module.exports = {
    cluster_afr_fullmesh,
    failure_rate_fullmesh,
    cluster_afr,
    print_cluster_afr,
    c_n_k,
 };
 print_cluster_afr({ n_hosts: 4, n_drives: 6, afr_drive: 0.03, afr_host: 0.05, capacity: 4000, speed: 0.1, replicas: 2 });
 print_cluster_afr({ n_hosts: 4, n_drives: 3, afr_drive: 0.03, capacity: 4000, speed: 0.1, replicas: 2 });
 print_cluster_afr({ n_hosts: 4, n_drives: 3, afr_drive: 0.03, afr_host: 0.05, capacity: 4000, speed: 0.1, replicas: 2 });
 print_cluster_afr({ n_hosts: 4, n_drives: 3, afr_drive: 0.03, capacity: 4000, speed: 0.1, ec: [ 2, 1 ] });
 print_cluster_afr({ n_hosts: 4, n_drives: 3, afr_drive: 0.03, afr_host: 0.05, capacity: 4000, speed: 0.1, ec: [ 2, 1 ] });
 print_cluster_afr({ n_hosts: 10, n_drives: 10, afr_drive: 0.1, capacity: 8000, speed: 0.02, replicas: 2 });
 print_cluster_afr({ n_hosts: 10, n_drives: 10, afr_drive: 0.1, afr_host: 0.05, capacity: 8000, speed: 0.02, replicas: 2 });
 print_cluster_afr({ n_hosts: 10, n_drives: 10, afr_drive: 0.1, capacity: 8000, speed: 0.02, replicas: 3 });
 print_cluster_afr({ n_hosts: 10, n_drives: 10, afr_drive: 0.1, afr_host: 0.05, capacity: 8000, speed: 0.02, replicas: 3 });
 print_cluster_afr({ n_hosts: 10, n_drives: 10, afr_drive: 0.1, capacity: 8000, speed: 0.02, replicas: 3, pgs: 100 });
 print_cluster_afr({ n_hosts: 10, n_drives: 10, afr_drive: 0.1, afr_host: 0.05, capacity: 8000, speed: 0.02, replicas: 3, pgs: 100 });
 print_cluster_afr({ n_hosts: 10, n_drives: 10, afr_drive: 0.1, afr_host: 0.05, capacity: 8000, speed: 0.02, replicas: 3, pgs: 100, degraded_replacement: 1 });
 /******** "FULL MESH": ASSUME EACH OSD COMMUNICATES WITH ALL OTHER OSDS ********/
 // Estimate AFR of the cluster
 // n - number of drives
 // afr - annualized failure rate of a single drive
 // l - expected rebalance time in days after a single drive failure
 // k - replication factor / number of drives that must fail at the same time for the cluster to fail
 function cluster_afr_fullmesh(n, afr, l, k)
 {
    return 1 - (1 - afr * failure_rate_fullmesh(n-(k-1), afr*l/365, k-1)) ** (n-(k-1));
 }
 // Probability of at least <f> failures in a cluster with <n> drives with AFR=<a>
 function failure_rate_fullmesh(n, a, f)
 {
    if (f <= 0)
    {
        return (1-a)**n;
    }
    let p = 1;
    for (let i = 0; i < f; i++)
    {
        p -= c_n_k(n, i) * (1-a)**(n-i) * a**i;
    }
    return p;
 }
 /******** PGS: EACH OSD ONLY COMMUNICATES WITH <pgs> OTHER OSDs ********/
 // <n> hosts of <m> drives of <capacity> GB, each able to backfill at <speed> GB/s,
 // <k> replicas, <pgs> unique peer PGs per OSD
 //
 // For each of n*m drives: P(drive fails in a year) * P(any of its peers fail in <l*365> next days).
 // More peers per OSD increase rebalance speed (more drives work together to resilver) if you
 // let them finish rebalance BEFORE replacing the failed drive.
 // At the same time, more peers per OSD increase probability of any of them to fail!
 //
 // Probability of all except one drives in a replica group to fail is (AFR^(k-1)).
 // So with <x> PGs it becomes ~ (x * (AFR*L/365)^(k-1)). Interesting but reasonable consequence
 // is that, with k=2, total failure rate doesn't depend on number of peers per OSD,
 // because it gets increased linearly by increased number of peers to fail
 // and decreased linearly by reduced rebalance time.
 function cluster_afr_pgs({ n_hosts, n_drives, afr_drive, capacity, speed, replicas, pgs = 1, degraded_replacement })
 {
    pgs = Math.min(pgs, (n_hosts-1)*n_drives/(replicas-1));
    const l = capacity/(degraded_replacement ? 1 : pgs)/speed/86400/365;
    return 1 - (1 - afr_drive * (1-(1-(afr_drive*l)**(replicas-1))**pgs)) ** (n_hosts*n_drives);
 }
 function cluster_afr_pgs_ec({ n_hosts, n_drives, afr_drive, capacity, speed, ec: [ ec_data, ec_parity ], pgs = 1, degraded_replacement })
 {
    const ec_total = ec_data+ec_parity;
    pgs = Math.min(pgs, (n_hosts-1)*n_drives/(ec_total-1));
    const l = capacity/(degraded_replacement ? 1 : pgs)/speed/86400/365;
    return 1 - (1 - afr_drive * (1-(1-failure_rate_fullmesh(ec_total-1, afr_drive*l, ec_parity))**pgs)) ** (n_hosts*n_drives);
 }
 // Same as above, but also take server failures into account
 function cluster_afr_pgs_hosts({ n_hosts, n_drives, afr_drive, afr_host, capacity, speed, replicas, pgs = 1, degraded_replacement })
 {
    let otherhosts = Math.min(pgs, (n_hosts-1)/(replicas-1));
    pgs = Math.min(pgs, (n_hosts-1)*n_drives/(replicas-1));
    let pgh = Math.min(pgs*n_drives, (n_hosts-1)*n_drives/(replicas-1));
    const ld = capacity/(degraded_replacement ? 1 : pgs)/speed/86400/365;
    const lh = n_drives*capacity/pgs/speed/86400/365;
    const p1 = ((afr_drive+afr_host*pgs/otherhosts)*lh);
    const p2 = ((afr_drive+afr_host*pgs/otherhosts)*ld);
    return 1 - ((1 - afr_host * (1-(1-p1**(replicas-1))**pgh)) ** n_hosts) *
        ((1 - afr_drive * (1-(1-p2**(replicas-1))**pgs)) ** (n_hosts*n_drives));
 }
 function cluster_afr_pgs_ec_hosts({ n_hosts, n_drives, afr_drive, afr_host, capacity, speed, ec: [ ec_data, ec_parity ], pgs = 1, degraded_replacement })
 {
    const ec_total = ec_data+ec_parity;
    const otherhosts = Math.min(pgs, (n_hosts-1)/(ec_total-1));
    pgs = Math.min(pgs, (n_hosts-1)*n_drives/(ec_total-1));
    const pgh = Math.min(pgs*n_drives, (n_hosts-1)*n_drives/(ec_total-1));
    const ld = capacity/(degraded_replacement ? 1 : pgs)/speed/86400/365;
    const lh = n_drives*capacity/pgs/speed/86400/365;
    const p1 = ((afr_drive+afr_host*pgs/otherhosts)*lh);
    const p2 = ((afr_drive+afr_host*pgs/otherhosts)*ld);
    return 1 - ((1 - afr_host * (1-(1-failure_rate_fullmesh(ec_total-1, p1, ec_parity))**pgh)) ** n_hosts) *
        ((1 - afr_drive * (1-(1-failure_rate_fullmesh(ec_total-1, p2, ec_parity))**pgs)) ** (n_hosts*n_drives));
 }
 // Wrapper for 4 above functions
 function cluster_afr(config)
 {
    if (config.ec && config.afr_host)
    {
        return cluster_afr_pgs_ec_hosts(config);
    }
    else if (config.ec)
    {
        return cluster_afr_pgs_ec(config);
    }
    else if (config.afr_host)
    {
        return cluster_afr_pgs_hosts(config);
    }
    else
    {
        return cluster_afr_pgs(config);
    }
 }
 function print_cluster_afr(config)
 {
    console.log(
        `${config.n_hosts} nodes with ${config.n_drives} ${sprintf("%.1f", config.capacity/1000)}TB drives`+
        `, capable to backfill at ${sprintf("%.1f", config.speed*1000)} MB/s, drive AFR ${sprintf("%.1f", config.afr_drive*100)}%`+
        (config.afr_host ? `, host AFR ${sprintf("%.1f", config.afr_host*100)}%` : '')+
        (config.ec ? `, EC ${config.ec[0]}+${config.ec[1]}` : `, ${config.replicas} replicas`)+
        `, ${config.pgs||1} PG per OSD`+
        (config.degraded_replacement ? `\n...and you don't let the rebalance finish before replacing drives` : '')
    );
    console.log('-> '+sprintf("%.7f%%", 100*cluster_afr(config))+'\n');
 }
 /******** UTILITY ********/
 // Combination count
 function c_n_k(n, k)
 {
    let r = 1;
    for (let i = 0; i < k; i++)
    {
        r *= (n-i) / (i+1);
    }
    return r;
 }
--- a/mon/lp-optimizer.js
+++ b/mon/lp-optimizer.js
@ -1,688 +0,0 @@
 // Copyright (c) Vitaliy Filippov, 2019+
 // License: VNPL-1.0 (see README.md for details)
 // Data distribution optimizer using linear programming (lp_solve)
 const child_process = require('child_process');
 const NO_OSD = 'Z';
 async function lp_solve(text)
 {
    const cp = child_process.spawn('lp_solve');
    let stdout = '', stderr = '', finish_cb;
    cp.stdout.on('data', buf => stdout += buf.toString());
    cp.stderr.on('data', buf => stderr += buf.toString());
    cp.on('exit', () => finish_cb && finish_cb());
    cp.stdin.write(text);
    cp.stdin.end();
    if (cp.exitCode == null)
    {
        await new Promise(ok => finish_cb = ok);
    }
    if (!stdout.trim())
    {
        return null;
    }
    let score = 0;
    let vars = {};
    for (const line of stdout.split(/\n/))
    {
        let m = /^(^Value of objective function: (-?[\d\.]+)|Actual values of the variables:)\s*$/.exec(line);
        if (m)
        {
            if (m[2])
            {
                score = m[2];
            }
            continue;
        }
        else if (/This problem is (infeasible|unbounded)/.exec(line))
        {
            return null;
        }
        let [ k, v ] = line.trim().split(/\s+/, 2);
        if (v)
        {
            vars[k] = v;
        }
    }
    return { score, vars };
 }
 async function optimize_initial({ osd_tree, pg_count, pg_size = 3, pg_minsize = 2, max_combinations = 10000, parity_space = 1 })
 {
    if (!pg_count || !osd_tree)
    {
        return null;
    }
    const all_weights = Object.assign({}, ...Object.values(osd_tree));
    const total_weight = Object.values(all_weights).reduce((a, c) => Number(a) + Number(c), 0);
    const all_pgs = Object.values(random_combinations(osd_tree, pg_size, max_combinations));
    const pg_per_osd = {};
    for (const pg of all_pgs)
    {
        for (let i = 0; i < pg.length; i++)
        {
            const osd = pg[i];
            pg_per_osd[osd] = pg_per_osd[osd] || [];
            pg_per_osd[osd].push((i >= pg_minsize ? parity_space+'*' : '')+"pg_"+pg.join("_"));
        }
    }
    const pg_effsize = Math.min(pg_minsize, Object.keys(osd_tree).length)
        + Math.max(0, Math.min(pg_size, Object.keys(osd_tree).length) - pg_minsize) * parity_space;
    let lp = '';
    lp += "max: "+all_pgs.map(pg => 'pg_'+pg.join('_')).join(' + ')+";\n";
    for (const osd in pg_per_osd)
    {
        if (osd !== NO_OSD)
        {
            let osd_pg_count = all_weights[osd]/total_weight*pg_effsize*pg_count;
            lp += pg_per_osd[osd].join(' + ')+' <= '+osd_pg_count+';\n';
        }
    }
    for (const pg of all_pgs)
    {
        lp += 'pg_'+pg.join('_')+" >= 0;\n";
    }
    lp += "sec "+all_pgs.map(pg => 'pg_'+pg.join('_')).join(', ')+";\n";
    const lp_result = await lp_solve(lp);
    if (!lp_result)
    {
        console.log(lp);
        throw new Error('Problem is infeasible or unbounded - is it a bug?');
    }
    const int_pgs = make_int_pgs(lp_result.vars, pg_count);
    const eff = pg_list_space_efficiency(int_pgs, all_weights, pg_minsize, parity_space);
    const res = {
        score: lp_result.score,
        weights: lp_result.vars,
        int_pgs,
        space: eff * pg_effsize,
        total_space: total_weight,
    };
    return res;
 }
 function make_int_pgs(weights, pg_count)
 {
    const total_weight = Object.values(weights).reduce((a, c) => Number(a) + Number(c), 0);
    let int_pgs = [];
    let pg_left = pg_count;
    let weight_left = total_weight;
    for (const pg_name in weights)
    {
        let n = Math.round(weights[pg_name] / weight_left * pg_left);
        for (let i = 0; i < n; i++)
        {
            int_pgs.push(pg_name.substr(3).split('_'));
        }
        weight_left -= weights[pg_name];
        pg_left -= n;
    }
    return int_pgs;
 }
 function calc_intersect_weights(pg_size, pg_count, prev_weights, all_pgs)
 {
    const move_weights = {};
    if ((1 << pg_size) < pg_count)
    {
        const intersect = {};
        for (const pg_name in prev_weights)
        {
            const pg = pg_name.substr(3).split(/_/);
            for (let omit = 1; omit < (1 << pg_size); omit++)
            {
                let pg_omit = [ ...pg ];
                let intersect_count = pg_size;
                for (let i = 0; i < pg_size; i++)
                {
                    if (omit & (1 << i))
                    {
                        pg_omit[i] = '';
                        intersect_count--;
                    }
                }
                pg_omit = pg_omit.join(':');
                intersect[pg_omit] = Math.max(intersect[pg_omit] || 0, intersect_count);
            }
        }
        for (const pg of all_pgs)
        {
            let max_int = 0;
            for (let omit = 1; omit < (1 << pg_size); omit++)
            {
                let pg_omit = [ ...pg ];
                for (let i = 0; i < pg_size; i++)
                {
                    if (omit & (1 << i))
                    {
                        pg_omit[i] = '';
                    }
                }
                pg_omit = pg_omit.join(':');
                max_int = Math.max(max_int, intersect[pg_omit] || 0);
            }
            move_weights['pg_'+pg.join('_')] = pg_size-max_int;
        }
    }
    else
    {
        const prev_pg_hashed = Object.keys(prev_weights).map(pg_name => pg_name.substr(3).split(/_/).reduce((a, c) => { a[c] = 1; return a; }, {}));
        for (const pg of all_pgs)
        {
            if (!prev_weights['pg_'+pg.join('_')])
            {
                let max_int = 0;
                for (const prev_hash in prev_pg_hashed)
                {
                    const intersect_count = pg.reduce((a, osd) => a + (prev_hash[osd] ? 1 : 0), 0);
                    if (max_int < intersect_count)
                    {
                        max_int = intersect_count;
                        if (max_int >= pg_size)
                        {
                            break;
                        }
                    }
                }
                move_weights['pg_'+pg.join('_')] = pg_size-max_int;
            }
        }
    }
    return move_weights;
 }
 function add_valid_previous(osd_tree, prev_weights, all_pgs)
 {
    // Add previous combinations that are still valid
    const hosts = Object.keys(osd_tree).sort();
    const host_per_osd = {};
    for (const host in osd_tree)
    {
        for (const osd in osd_tree[host])
        {
            host_per_osd[osd] = host;
        }
    }
    skip_pg: for (const pg_name in prev_weights)
    {
        const seen_hosts = {};
        const pg = pg_name.substr(3).split(/_/);
        for (const osd of pg)
        {
            if (!host_per_osd[osd] || seen_hosts[host_per_osd[osd]])
            {
                continue skip_pg;
            }
            seen_hosts[host_per_osd[osd]] = true;
        }
        if (!all_pgs[pg_name])
        {
            all_pgs[pg_name] = pg;
        }
    }
 }
 // Try to minimize data movement
 async function optimize_change({ prev_pgs: prev_int_pgs, osd_tree, pg_size = 3, pg_minsize = 2, max_combinations = 10000, parity_space = 1 })
 {
    if (!osd_tree)
    {
        return null;
    }
    const pg_effsize = Math.min(pg_minsize, Object.keys(osd_tree).length)
        + Math.max(0, Math.min(pg_size, Object.keys(osd_tree).length) - pg_minsize) * parity_space;
    const pg_count = prev_int_pgs.length;
    const prev_weights = {};
    const prev_pg_per_osd = {};
    for (const pg of prev_int_pgs)
    {
        const pg_name = 'pg_'+pg.join('_');
        prev_weights[pg_name] = (prev_weights[pg_name]||0) + 1;
        for (let i = 0; i < pg.length; i++)
        {
            const osd = pg[i];
            prev_pg_per_osd[osd] = prev_pg_per_osd[osd] || [];
            prev_pg_per_osd[osd].push([ pg_name, (i >= pg_minsize ? parity_space : 1) ]);
        }
    }
    // Get all combinations
    let all_pgs = random_combinations(osd_tree, pg_size, max_combinations);
    add_valid_previous(osd_tree, prev_weights, all_pgs);
    all_pgs = Object.values(all_pgs);
    const pg_per_osd = {};
    for (const pg of all_pgs)
    {
        const pg_name = 'pg_'+pg.join('_');
        for (let i = 0; i < pg.length; i++)
        {
            const osd = pg[i];
            pg_per_osd[osd] = pg_per_osd[osd] || [];
            pg_per_osd[osd].push([ pg_name, (i >= pg_minsize ? parity_space : 1) ]);
        }
    }
    // Penalize PGs based on their similarity to old PGs
    const move_weights = calc_intersect_weights(pg_size, pg_count, prev_weights, all_pgs);
    // Calculate total weight - old PG weights
    const all_pg_names = all_pgs.map(pg => 'pg_'+pg.join('_'));
    const all_pgs_hash = all_pg_names.reduce((a, c) => { a[c] = true; return a; }, {});
    const all_weights = Object.assign({}, ...Object.values(osd_tree));
    const total_weight = Object.values(all_weights).reduce((a, c) => Number(a) + Number(c), 0);
    // Generate the LP problem
    let lp = '';
    lp += 'max: '+all_pg_names.map(pg_name => (
        prev_weights[pg_name] ? `${pg_size+1}*add_${pg_name} - ${pg_size+1}*del_${pg_name}` : `${pg_size+1-move_weights[pg_name]}*${pg_name}`
    )).join(' + ')+';\n';
    for (const osd in pg_per_osd)
    {
        if (osd !== NO_OSD)
        {
            const osd_sum = (pg_per_osd[osd]||[]).map(([ pg_name, space ]) => (
                prev_weights[pg_name] ? `${space} * add_${pg_name} - ${space} * del_${pg_name}` : `${space} * ${pg_name}`
            )).join(' + ');
            const rm_osd_pg_count = (prev_pg_per_osd[osd]||[])
                .reduce((a, [ old_pg_name, space ]) => (a + (all_pgs_hash[old_pg_name] ? space : 0)), 0);
            const osd_pg_count = all_weights[osd]*pg_effsize/total_weight*pg_count - rm_osd_pg_count;
            lp += osd_sum + ' <= ' + osd_pg_count + ';\n';
        }
    }
    let pg_vars = [];
    for (const pg_name of all_pg_names)
    {
        if (prev_weights[pg_name])
        {
            pg_vars.push(`add_${pg_name}`, `del_${pg_name}`);
            // Can't add or remove less than zero
            lp += `add_${pg_name} >= 0;\n`;
            lp += `del_${pg_name} >= 0;\n`;
            // Can't remove more than the PG already has
            lp += `add_${pg_name} - del_${pg_name} >= -${prev_weights[pg_name]};\n`;
        }
        else
        {
            pg_vars.push(pg_name);
            lp += `${pg_name} >= 0;\n`;
        }
    }
    lp += 'sec '+pg_vars.join(', ')+';\n';
    // Solve it
    const lp_result = await lp_solve(lp);
    if (!lp_result)
    {
        console.log(lp);
        throw new Error('Problem is infeasible or unbounded - is it a bug?');
    }
    // Generate the new distribution
    const weights = { ...prev_weights };
    for (const k in prev_weights)
    {
        if (!all_pgs_hash[k])
        {
            delete weights[k];
        }
    }
    for (const k in lp_result.vars)
    {
        if (k.substr(0, 4) === 'add_')
        {
            weights[k.substr(4)] = (weights[k.substr(4)] || 0) + Number(lp_result.vars[k]);
        }
        else if (k.substr(0, 4) === 'del_')
        {
            weights[k.substr(4)] = (weights[k.substr(4)] || 0) - Number(lp_result.vars[k]);
        }
        else if (k.substr(0, 3) === 'pg_')
        {
            weights[k] = Number(lp_result.vars[k]);
        }
    }
    for (const k in weights)
    {
        if (!weights[k])
        {
            delete weights[k];
        }
    }
    const int_pgs = make_int_pgs(weights, pg_count);
    // Align them with most similar previous PGs
    const new_pgs = align_pgs(prev_int_pgs, int_pgs);
    let differs = 0, osd_differs = 0;
    for (let i = 0; i < pg_count; i++)
    {
        if (new_pgs[i].join('_') != prev_int_pgs[i].join('_'))
        {
            differs++;
        }
        for (let j = 0; j < pg_size; j++)
        {
            if (new_pgs[i][j] != prev_int_pgs[i][j])
            {
                osd_differs++;
            }
        }
    }
    return {
        prev_pgs: prev_int_pgs,
        score: lp_result.score,
        weights,
        int_pgs: new_pgs,
        differs,
        osd_differs,
        space: pg_effsize * pg_list_space_efficiency(new_pgs, all_weights, pg_minsize, parity_space),
        total_space: total_weight,
    };
 }
 function print_change_stats(retval, detailed)
 {
    const new_pgs = retval.int_pgs;
    const prev_int_pgs = retval.prev_pgs;
    if (prev_int_pgs)
    {
        if (detailed)
        {
            for (let i = 0; i < new_pgs.length; i++)
            {
                if (new_pgs[i].join('_') != prev_int_pgs[i].join('_'))
                {
                    console.log("pg "+i+": "+prev_int_pgs[i].join(' ')+" -> "+new_pgs[i].join(' '));
                }
            }
        }
        console.log(
            "Data movement: "+retval.differs+" pgs, "+
            retval.osd_differs+" pg*osds = "+Math.round(retval.osd_differs / prev_int_pgs.length / 3 * 10000)/100+" %"
        );
    }
    console.log(
        "Total space (raw): "+Math.round(retval.space*100)/100+" TB, space efficiency: "+
        Math.round(retval.space/(retval.total_space||1)*10000)/100+" %"
    );
 }
 function align_pgs(prev_int_pgs, int_pgs)
 {
    const aligned_pgs = [];
    put_aligned_pgs(aligned_pgs, int_pgs, prev_int_pgs, (pg) => [ pg.join(':') ]);
    put_aligned_pgs(aligned_pgs, int_pgs, prev_int_pgs, (pg) => [ pg[0]+'::'+pg[2], ':'+pg[1]+':'+pg[2], pg[0]+':'+pg[1]+':' ]);
    put_aligned_pgs(aligned_pgs, int_pgs, prev_int_pgs, (pg) => [ pg[0]+'::', ':'+pg[1]+':', '::'+pg[2] ]);
    const free_slots = prev_int_pgs.map((pg, i) => !aligned_pgs[i] ? i : null).filter(i => i != null);
    for (const pg of int_pgs)
    {
        if (!free_slots.length)
        {
            throw new Error("Can't place unaligned PG");
        }
        aligned_pgs[free_slots.shift()] = pg;
    }
    return aligned_pgs;
 }
 function put_aligned_pgs(aligned_pgs, int_pgs, prev_int_pgs, keygen)
 {
    let prev_indexes = {};
    for (let i = 0; i < prev_int_pgs.length; i++)
    {
        for (let k of keygen(prev_int_pgs[i]))
        {
            prev_indexes[k] = prev_indexes[k] || [];
            prev_indexes[k].push(i);
        }
    }
    PG: for (let i = int_pgs.length-1; i >= 0; i--)
    {
        let pg = int_pgs[i];
        let keys = keygen(int_pgs[i]);
        for (let k of keys)
        {
            while (prev_indexes[k] && prev_indexes[k].length)
            {
                let idx = prev_indexes[k].shift();
                if (!aligned_pgs[idx])
                {
                    aligned_pgs[idx] = pg;
                    int_pgs.splice(i, 1);
                    continue PG;
                }
            }
        }
    }
 }
 // Convert multi-level osd_tree = { level: number|string, id?: string, size?: number, children?: osd_tree }[]
 // levels = { string: number }
 // to a two-level osd_tree suitable for all_combinations()
 function flatten_tree(osd_tree, levels, failure_domain_level, osd_level, domains = {}, i = { i: 1 })
 {
    osd_level = levels[osd_level] || osd_level;
    failure_domain_level = levels[failure_domain_level] || failure_domain_level;
    for (const node of osd_tree)
    {
        if ((levels[node.level] || node.level) < failure_domain_level)
        {
            flatten_tree(node.children||[], levels, failure_domain_level, osd_level, domains, i);
        }
        else
        {
            domains['dom'+(i.i++)] = extract_osds([ node ], levels, osd_level);
        }
    }
    return domains;
 }
 function extract_osds(osd_tree, levels, osd_level, osds = {})
 {
    for (const node of osd_tree)
    {
        if ((levels[node.level] || node.level) >= osd_level)
        {
            osds[node.id] = node.size;
        }
        else
        {
            extract_osds(node.children||[], levels, osd_level, osds);
        }
    }
    return osds;
 }
 function random_combinations(osd_tree, pg_size, count)
 {
    let seed = 0x5f020e43;
    let rng = () =>
    {
        seed ^= seed << 13;
        seed ^= seed >> 17;
        seed ^= seed << 5;
        return seed + 2147483648;
    };
    const hosts = Object.keys(osd_tree).sort();
    const osds = Object.keys(osd_tree).reduce((a, c) => { a[c] = Object.keys(osd_tree[c]).sort(); return a; }, {});
    const r = {};
    // Generate random combinations including each OSD at least once
    for (let h = 0; h < hosts.length; h++)
    {
        for (let o = 0; o < osds[hosts[h]].length; o++)
        {
            const pg = [ osds[hosts[h]][o] ];
            const cur_hosts = [ ...hosts ];
            cur_hosts.splice(h, 1);
            for (let i = 1; i < pg_size && i < hosts.length; i++)
            {
                const next_host = rng() % cur_hosts.length;
                const next_osd = rng() % osds[cur_hosts[next_host]].length;
                pg.push(osds[cur_hosts[next_host]][next_osd]);
                cur_hosts.splice(next_host, 1);
            }
            while (pg.length < pg_size)
            {
                pg.push(NO_OSD);
            }
            r['pg_'+pg.join('_')] = pg;
        }
    }
    // Generate purely random combinations
    restart: while (count > 0)
    {
        let host_idx = [];
        for (let i = 0; i < pg_size && i < hosts.length; i++)
        {
            let start = i > 0 ? host_idx[i-1]+1 : 0;
            if (start >= hosts.length)
            {
                continue restart;
            }
            host_idx[i] = start + rng() % (hosts.length-start);
        }
        let pg = host_idx.map(h => osds[hosts[h]][rng() % osds[hosts[h]].length]);
        while (pg.length < pg_size)
        {
            pg.push(NO_OSD);
        }
        r['pg_'+pg.join('_')] = pg;
        count--;
    }
    return r;
 }
 // Super-stupid algorithm. Given the current OSD tree, generate all possible OSD combinations
 // osd_tree = { failure_domain1: { osd1: size1, ... }, ... }
 // ordered = return combinations without duplicates having different order
 function all_combinations(osd_tree, pg_size, ordered, count)
 {
    const hosts = Object.keys(osd_tree).sort();
    const osds = Object.keys(osd_tree).reduce((a, c) => { a[c] = Object.keys(osd_tree[c]).sort(); return a; }, {});
    while (hosts.length < pg_size)
    {
        osds[NO_OSD] = [ NO_OSD ];
        hosts.push(NO_OSD);
    }
    let host_idx = [];
    let osd_idx = [];
    for (let i = 0; i < pg_size; i++)
    {
        host_idx.push(i);
        osd_idx.push(0);
    }
    const r = [];
    while (!count || count < 0 || r.length < count)
    {
        r.push(host_idx.map((hi, i) => osds[hosts[hi]][osd_idx[i]]));
        let inc = pg_size-1;
        while (inc >= 0)
        {
            osd_idx[inc]++;
            if (osd_idx[inc] >= osds[hosts[host_idx[inc]]].length)
            {
                osd_idx[inc] = 0;
                inc--;
            }
            else
            {
                break;
            }
        }
        if (inc < 0)
        {
            // no osds left in the current host combination, select the next one
            inc = pg_size-1;
            same_again: while (inc >= 0)
            {
                host_idx[inc]++;
                for (let prev_host = 0; prev_host < inc; prev_host++)
                {
                    if (host_idx[prev_host] == host_idx[inc])
                    {
                        continue same_again;
                    }
                }
                if (host_idx[inc] < (ordered ? hosts.length-(pg_size-1-inc) : hosts.length))
                {
                    while ((++inc) < pg_size)
                    {
                        host_idx[inc] = (ordered ? host_idx[inc-1]+1 : 0);
                    }
                    break;
                }
                else
                {
                    inc--;
                }
            }
            if (inc < 0)
            {
                break;
            }
        }
    }
    return r;
 }
 function pg_weights_space_efficiency(weights, pg_count, osd_sizes)
 {
    const per_osd = {};
    for (const pg_name in weights)
    {
        for (const osd of pg_name.substr(3).split(/_/))
        {
            per_osd[osd] = (per_osd[osd]||0) + weights[pg_name];
        }
    }
    return pg_per_osd_space_efficiency(per_osd, pg_count, osd_sizes);
 }
 function pg_list_space_efficiency(pgs, osd_sizes, pg_minsize, parity_space)
 {
    const per_osd = {};
    for (const pg of pgs)
    {
        for (let i = 0; i < pg.length; i++)
        {
            const osd = pg[i];
            per_osd[osd] = (per_osd[osd]||0) + (i >= pg_minsize ? (parity_space||1) : 1);
        }
    }
    return pg_per_osd_space_efficiency(per_osd, pgs.length, osd_sizes);
 }
 function pg_per_osd_space_efficiency(per_osd, pg_count, osd_sizes)
 {
    // each PG gets randomly selected in 1/N cases
    // & there are x PGs per OSD
    // => an OSD is selected in x/N cases
    // => total space * x/N <= OSD size
    // => total space <= OSD size * N/x
    let space;
    for (let osd in per_osd)
    {
        if (osd in osd_sizes)
        {
            const space_estimate = osd_sizes[osd] * pg_count / per_osd[osd];
            if (space == null || space > space_estimate)
            {
                space = space_estimate;
            }
        }
    }
    return space == null ? 0 : space;
 }
 module.exports = {
    NO_OSD,
    optimize_initial,
    optimize_change,
    print_change_stats,
    pg_weights_space_efficiency,
    pg_list_space_efficiency,
    pg_per_osd_space_efficiency,
    flatten_tree,
    lp_solve,
    make_int_pgs,
    align_pgs,
    random_combinations,
    all_combinations,
 };
--- a/mon/make-units.sh
+++ b/mon/make-units.sh
@ -1,136 +0,0 @@
 #!/bin/bash
 # Example startup script generator
 # Of course this isn't a production solution yet, this is just for tests
 # Copyright (c) Vitaliy Filippov, 2019+
 # License: MIT
 IP=`ip -json a s | jq -r '.[].addr_info[] | select(.broadcast == "10.115.0.255") | .local'`
 [ "$IP" != "" ] || exit 1
 useradd vitastor
 chmod 755 /root
 BASE=${IP/*./}
 BASE=$(((BASE-10)*12))
 cat >/etc/systemd/system/vitastor.target <<EOF
 [Unit]
 Description=vitastor target
 [Install]
 WantedBy=multi-user.target
 EOF
 i=1
 for DEV in `ls /dev/disk/by-id/ | grep ata-INTEL_SSDSC2KB`; do
    dd if=/dev/zero of=/dev/disk/by-id/$DEV bs=1048576 count=$(((427814912+1048575)/1048576+2))
    dd if=/dev/zero of=/dev/disk/by-id/$DEV bs=1048576 count=$(((427814912+1048575)/1048576+2)) seek=$((1920377991168/1048576))
 cat >/etc/systemd/system/vitastor-osd$((BASE+i)).service <<EOF
 [Unit]
 Description=Vitastor object storage daemon osd.$((BASE+i))
 After=network-online.target local-fs.target time-sync.target
 Wants=network-online.target local-fs.target time-sync.target
 PartOf=vitastor.target
 [Service]
 LimitNOFILE=1048576
 LimitNPROC=1048576
 LimitMEMLOCK=infinity
 ExecStart=/root/vitastor/osd \\
    --etcd_address $IP:2379/v3 \\
    --bind_address $IP \\
    --osd_num $((BASE+i)) \\
    --disable_data_fsync 1 \\
    --disable_device_lock 1 \\
    --immediate_commit all \\
    --flusher_count 8 \\
    --disk_alignment 4096 --journal_block_size 4096 --meta_block_size 4096 \\
    --journal_no_same_sector_overwrites true \\
    --journal_sector_buffer_count 1024 \\
    --journal_offset 0 \\
    --meta_offset 16777216 \\
    --data_offset 427814912 \\
    --data_size $((1920377991168-427814912)) \\
    --data_device /dev/disk/by-id/$DEV
 WorkingDirectory=/root/vitastor
 ExecStartPre=+chown vitastor:vitastor /dev/disk/by-id/$DEV
 User=vitastor
 PrivateTmp=false
 TasksMax=infinity
 Restart=always
 StartLimitInterval=0
 StartLimitIntervalSec=0
 RestartSec=10
 [Install]
 WantedBy=vitastor.target
 EOF
    systemctl enable vitastor-osd$((BASE+i))
    i=$((i+1))
 cat >/etc/systemd/system/vitastor-osd$((BASE+i)).service <<EOF
 [Unit]
 Description=Vitastor object storage daemon osd.$((BASE+i))
 After=network-online.target local-fs.target time-sync.target
 Wants=network-online.target local-fs.target time-sync.target
 PartOf=vitastor.target
 [Service]
 LimitNOFILE=1048576
 LimitNPROC=1048576
 LimitMEMLOCK=infinity
 ExecStart=/root/vitastor/osd \\
    --etcd_address $IP:2379/v3 \\
    --bind_address $IP \\
    --osd_num $((BASE+i)) \\
    --disable_data_fsync 1 \\
    --immediate_commit all \\
    --flusher_count 8 \\
    --disk_alignment 4096 --journal_block_size 4096 --meta_block_size 4096 \\
    --journal_no_same_sector_overwrites true \\
    --journal_sector_buffer_count 1024 \\
    --journal_offset 1920377991168 \\
    --meta_offset $((1920377991168+16777216)) \\
    --data_offset $((1920377991168+427814912)) \\
    --data_size $((1920377991168-427814912)) \\
    --data_device /dev/disk/by-id/$DEV
 WorkingDirectory=/root/vitastor
 ExecStartPre=+chown vitastor:vitastor /dev/disk/by-id/$DEV
 User=vitastor
 PrivateTmp=false
 TasksMax=infinity
 Restart=always
 StartLimitInterval=0
 StartLimitIntervalSec=0
 RestartSec=10
 [Install]
 WantedBy=vitastor.target
 EOF
    systemctl enable vitastor-osd$((BASE+i))
    i=$((i+1))
 done
 exit
 node mon-main.js --etcd_url 'http://10.115.0.10:2379,http://10.115.0.11:2379,http://10.115.0.12:2379,http://10.115.0.13:2379' --etcd_prefix '/vitastor' --etcd_start_timeout 5
 podman run -d --network host --restart always -v /var/lib/etcd0.etcd:/etcd0.etcd --name etcd quay.io/coreos/etcd:v3.4.13 etcd -name etcd0 \
    -advertise-client-urls http://10.115.0.10:2379 -listen-client-urls http://10.115.0.10:2379 \
    -initial-advertise-peer-urls http://10.115.0.10:2380 -listen-peer-urls http://10.115.0.10:2380 \
    -initial-cluster-token vitastor-etcd-1 -initial-cluster etcd0=http://10.115.0.10:2380,etcd1=http://10.115.0.11:2380,etcd2=http://10.115.0.12:2380,etcd3=http://10.115.0.13:2380 \
    -initial-cluster-state new --max-txn-ops=100000 --auto-compaction-retention=10 --auto-compaction-mode=revision
 etcdctl --endpoints http://10.115.0.10:2379 put /vitastor/config/global '{"immediate_commit":"all"}'
 etcdctl --endpoints http://10.115.0.10:2379 put /vitastor/config/pools '{"1":{"name":"testpool","scheme":"replicated","pg_size":2,"pg_minsize":1,"pg_count":48,"failure_domain":"host"}}'
 #let pgs = {};
 #for (let n = 0; n < 48; n++) { let i = n/2 | 0; pgs[1+n] = { osd_set: [ (1+i%12+(i/12 | 0)*24), (1+12+i%12+(i/12 | 0)*24) ], primary: (1+(n%2)*12+i%12+(i/12 | 0)*24) }; };
 #console.log(JSON.stringify({ items: { 1: pgs } }));
 #etcdctl --endpoints http://10.115.0.10:2379 put /vitastor/config/pgs ...
 #    --disk_alignment 4096 --journal_block_size 4096 --meta_block_size 4096 \\
 #    --data_offset 427814912 \\
 #    --disk_alignment 4096 --journal_block_size 512 --meta_block_size 512 \\
 #    --data_offset 433434624 \\
--- a/mon/mon-main.js
+++ b/mon/mon-main.js
@ -1,25 +0,0 @@
 #!/usr/bin/node
 // Copyright (c) Vitaliy Filippov, 2019+
 // License: VNPL-1.0 (see README.md for details)
 const Mon = require('./mon.js');
 const options = {};
 for (let i = 2; i < process.argv.length; i++)
 {
    if (process.argv[i].substr(0, 2) == '--')
    {
        options[process.argv[i].substr(2)] = process.argv[i+1];
        i++;
    }
 }
 if (!options.etcd_url)
 {
    console.error('USAGE: '+process.argv[0]+' '+process.argv[1]+' --etcd_url "http://127.0.0.1:2379,..." --etcd_prefix "/vitastor" --etcd_start_timeout 5 [--verbose 1]');
    process.exit();
 }
 new Mon(options).start().catch(e => { console.error(e); process.exit(); });
--- a/mon/mon.js
+++ b/mon/mon.js
--- a/mon/package.json
+++ b/mon/package.json
@ -1,15 +0,0 @@
 {
  "name": "vitastor-mon",
  "version": "1.0.0",
  "description": "Vitastor SDS monitor service",
  "main": "mon-main.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "author": "Vitaliy Filippov",
  "license": "UNLICENSED",
  "dependencies": {
    "sprintf-js": "^1.1.2",
    "ws": "^7.2.5"
  }
 }
--- a/mon/simple-offsets.js
+++ b/mon/simple-offsets.js
@ -1,56 +0,0 @@
 // Copyright (c) Vitaliy Filippov, 2019+
 // License: MIT
 // Simple tool to calculate journal and metadata offsets for a single device
 // Will be replaced by smarter tools in the future
 const child_process = require('child_process');
 async function run()
 {
    const options = {
        object_size: 128*1024,
        bitmap_granularity: 4096,
        journal_size: 16*1024*1024,
        device_block_size: 4096,
        journal_offset: 0,
        device_size: 0,
    };
    for (let i = 2; i < process.argv.length; i++)
    {
        if (process.argv[i].substr(0, 2) == '--')
        {
            options[process.argv[i].substr(2)] = process.argv[i+1];
            i++;
        }
    }
    const device_size = Number(options.device_size || await system("blockdev --getsize64 "+options.device));
    if (!device_size)
    {
        process.stderr.write('Failed to get device size\n');
        process.exit(1);
    }
    options.journal_offset = Math.ceil(options.journal_offset/options.device_block_size)*options.device_block_size;
    const meta_offset = options.journal_offset + Math.ceil(options.journal_size/options.device_block_size)*options.device_block_size;
    const entries_per_block = Math.floor(options.device_block_size / (24 + options.object_size/options.bitmap_granularity/8));
    const object_count = Math.floor((device_size-meta_offset)/options.object_size);
    const meta_size = Math.ceil(object_count / entries_per_block) * options.device_block_size;
    const data_offset = meta_offset + meta_size;
    const meta_size_fmt = (meta_size > 1024*1024*1024 ? Math.round(meta_size/1024/1024/1024*100)/100+" GB"
        : Math.round(meta_size/1024/1024*100)/100+" MB");
    process.stdout.write(
        `Metadata size: ${meta_size_fmt}\n`+
        `Options for the OSD:\n`+
        `    --journal_offset ${options.journal_offset}\n`+
        `    --meta_offset ${meta_offset}\n`+
        `    --data_offset ${data_offset}\n`+
        (options.device_size ? `    --data_size ${device_size-data_offset}\n` : '')
    );
 }
 function system(cmd)
 {
    return new Promise((ok, no) => child_process.exec(cmd, { maxBuffer: 64*1024*1024 }, (err, stdout, stderr) => (err ? no(err) : ok(stdout))));
 }
 run().catch(console.error);
--- a/mon/stable-stringify.js
+++ b/mon/stable-stringify.js
@ -1,78 +0,0 @@
 // Copyright (c) Vitaliy Filippov, 2019+
 // License: MIT
 function stableStringify(obj, opts)
 {
    if (!opts)
        opts = {};
    if (typeof opts === 'function')
        opts = { cmp: opts };
    let space = opts.space || '';
    if (typeof space === 'number')
        space = Array(space+1).join(' ');
    const cycles = (typeof opts.cycles === 'boolean') ? opts.cycles : false;
    const cmp = opts.cmp && (function (f)
    {
        return function (node)
        {
            return function (a, b)
            {
                let aobj = { key: a, value: node[a] };
                let bobj = { key: b, value: node[b] };
                return f(aobj, bobj);
            };
        };
    })(opts.cmp);
    const seen = new Map();
    return (function stringify (parent, key, node, level)
    {
        const indent = space ? ('\n' + new Array(level + 1).join(space)) : '';
        const colonSeparator = space ? ': ' : ':';
        if (node === undefined)
        {
            return;
        }
        if (typeof node !== 'object' || node === null)
        {
            return JSON.stringify(node);
        }
        if (node instanceof Array)
        {
            const out = [];
            for (let i = 0; i < node.length; i++)
            {
                const item = stringify(node, i, node[i], level+1) || JSON.stringify(null);
                out.push(indent + space + item);
            }
            return '[' + out.join(',') + indent + ']';
        }
        else
        {
            if (seen.has(node))
            {
                if (cycles)
                    return JSON.stringify('__cycle__');
                throw new TypeError('Converting circular structure to JSON');
            }
            else
                seen.set(node, true);
            const keys = Object.keys(node).sort(cmp && cmp(node));
            const out = [];
            for (let i = 0; i < keys.length; i++)
            {
                const key = keys[i];
                const value = stringify(node, key, node[key], level+1);
                if (!value)
                    continue;
                const keyValue = JSON.stringify(key)
                    + colonSeparator
                    + value;
                out.push(indent + space + keyValue);
            }
            seen.delete(node);
            return '{' + out.join(',') + indent + '}';
        }
    })({ '': obj }, '', obj, 0);
 }
 module.exports = stableStringify;
--- a/mon/test-nonuniform.js
+++ b/mon/test-nonuniform.js
@ -1,130 +0,0 @@
 // Copyright (c) Vitaliy Filippov, 2019+
 // License: VNPL-1.0 (see README.md for details)
 // Interesting real-world example coming from Ceph with EC and compression enabled.
 // EC parity chunks can't be compressed as efficiently as data chunks,
 // thus they occupy more space (2.26x more space) in OSD object stores.
 // This leads to really uneven OSD fill ratio in Ceph even when PGs are perfectly balanced.
 // But we support this case with the "parity_space" parameter in optimize_initial()/optimize_change().
 const LPOptimizer = require('./lp-optimizer.js');
 const osd_tree = {
    ripper5: {
        osd0: 3.493144989013672,
        osd1: 3.493144989013672,
        osd2: 3.454082489013672,
        osd12: 3.461894989013672,
    },
    ripper7: {
        osd4: 3.638690948486328,
        osd5: 3.638690948486328,
        osd6: 3.638690948486328,
    },
    ripper4: {
        osd9: 3.4609375,
        osd10: 3.4609375,
        osd11: 3.4609375,
    },
    ripper6: {
        osd3: 3.5849609375,
        osd7: 3.5859336853027344,
        osd8: 3.638690948486328,
        osd13: 3.461894989013672
    },
 };
 const prev_pgs = [[12,7,5],[6,11,12],[3,6,9],[10,0,5],[2,5,13],[9,8,6],[3,4,12],[7,4,12],[12,11,13],[13,6,0],[4,13,10],[9,7,6],[7,10,0],[10,8,0],[3,10,2],[3,0,4],[6,13,0],[13,10,0],[13,10,5],[8,11,6],[3,9,2],[2,8,5],[8,9,5],[3,12,11],[0,7,4],[13,11,1],[11,3,12],[12,8,10],[7,5,12],[2,13,5],[7,11,0],[13,2,6],[0,6,8],[13,1,6],[0,13,4],[0,8,10],[4,10,0],[8,12,4],[8,12,9],[12,7,4],[13,9,5],[3,2,11],[1,9,7],[1,8,5],[5,12,9],[3,5,12],[2,8,10],[0,8,4],[1,4,11],[7,10,2],[12,13,5],[3,1,11],[7,1,4],[4,12,8],[7,0,9],[11,1,8],[3,0,5],[11,13,0],[1,13,5],[12,7,10],[12,8,4],[11,13,5],[0,11,6],[2,11,3],[13,1,11],[2,7,10],[7,10,12],[7,12,10],[12,11,5],[13,12,10],[2,3,9],[4,3,9],[13,2,5],[7,12,6],[12,10,13],[9,8,1],[13,1,5],[9,5,12],[5,11,7],[6,2,9],[8,11,6],[12,5,8],[6,13,1],[7,6,11],[2,3,6],[8,5,9],[1,13,6],[9,3,2],[7,11,1],[3,10,1],[0,11,7],[3,0,5],[1,3,6],[6,0,9],[3,11,4],[8,10,2],[13,1,9],[12,6,9],[3,12,9],[12,8,9],[7,5,0],[8,12,5],[0,11,3],[12,11,13],[0,7,11],[0,3,10],[1,3,11],[2,7,11],[13,2,6],[9,12,13],[8,2,4],[0,7,4],[5,13,0],[13,12,9],[1,9,8],[0,10,3],[3,5,10],[7,12,9],[2,13,4],[12,7,5],[9,2,7],[3,2,9],[6,2,7],[3,1,9],[4,3,2],[5,3,11],[0,7,6],[1,6,13],[7,10,2],[12,4,8],[13,12,6],[7,5,11],[6,2,3],[2,7,6],[2,3,10],[2,7,10],[11,12,6],[0,13,5],[10,2,4],[13,0,11],[7,0,6],[8,9,4],[8,4,11],[7,11,2],[3,4,2],[6,1,3],[7,2,11],[8,9,4],[11,4,8],[10,3,1],[2,10,13],[1,7,11],[13,11,12],[2,6,9],[10,0,13],[7,10,4],[0,11,13],[13,10,1],[7,5,0],[7,12,10],[3,1,4],[7,1,5],[3,11,5],[7,5,0],[1,3,5],[10,5,12],[0,3,9],[7,1,11],[11,8,12],[3,6,2],[7,12,9],[7,11,12],[4,11,3],[0,11,13],[13,2,5],[1,5,8],[0,11,8],[3,5,1],[11,0,6],[3,11,2],[11,8,12],[4,1,3],[10,13,4],[13,9,6],[2,3,10],[12,7,9],[10,0,4],[10,13,2],[3,11,1],[7,2,9],[1,7,4],[13,1,4],[7,0,6],[5,3,9],[10,0,7],[0,7,10],[3,6,10],[13,0,5],[8,4,1],[3,1,10],[2,10,13],[13,0,5],[13,10,2],[12,7,9],[6,8,10],[6,1,8],[10,8,1],[13,5,0],[5,11,3],[7,6,1],[8,5,9],[2,13,11],[10,12,4],[13,4,1],[2,13,4],[11,7,0],[2,9,7],[1,7,6],[8,0,4],[8,1,9],[7,10,12],[13,9,6],[7,6,11],[13,0,4],[1,8,4],[3,12,5],[10,3,1],[10,2,13],[2,4,8],[6,2,3],[3,0,10],[6,7,12],[8,12,5],[3,0,6],[13,12,10],[11,3,6],[9,0,13],[10,0,6],[7,5,2],[1,3,11],[7,10,2],[2,9,8],[11,13,12],[0,8,4],[8,12,11],[6,0,3],[1,13,4],[11,8,2],[12,3,6],[4,7,1],[7,6,12],[3,10,6],[0,10,7],[8,9,1],[0,10,6],[8,10,1]]
    .map(pg => pg.map(n => 'osd'+n));
 const by_osd = {};
 for (let i = 0; i < prev_pgs.length; i++)
 {
    for (let j = 0; j < prev_pgs[i].length; j++)
    {
        by_osd[prev_pgs[i][j]] = by_osd[prev_pgs[i][j]] || [];
        by_osd[prev_pgs[i][j]][j] = (by_osd[prev_pgs[i][j]][j] || 0) + 1;
    }
 }
 /*
 This set of PGs was balanced by hand, by heavily tuning OSD weights in Ceph:
 {
  osd0: 4.2,
  osd1: 3.5,
  osd2: 3.45409,
  osd3: 4.5,
  osd4: 1.4,
  osd5: 1.4,
  osd6: 1.75,
  osd7: 4.5,
  osd8: 4.4,
  osd9: 2.2,
  osd10: 2.7,
  osd11: 2,
  osd12: 3.4,
  osd13: 3.4,
 }
 EC+compression is a nightmare in Ceph, yeah :))
 To calculate the average ratio between data chunks and parity chunks we
 calculate the number of PG chunks for each chunk role for each OSD:
 {
  osd12: [ 18, 22, 17 ],
  osd7: [ 35, 22, 8 ],
  osd5: [ 6, 17, 27 ],
  osd6: [ 13, 12, 28 ],
  osd11: [ 13, 26, 20 ],
  osd3: [ 30, 20, 10 ],
  osd9: [ 8, 12, 26 ],
  osd10: [ 15, 23, 20 ],
  osd0: [ 22, 22, 14 ],
  osd2: [ 22, 16, 16 ],
  osd13: [ 29, 19, 13 ],
  osd8: [ 20, 18, 12 ],
  osd4: [ 8, 10, 28 ],
  osd1: [ 17, 17, 17 ]
 }
 And now we can pick a pair of OSDs and determine the ratio by solving the following:
 osd5 = 23*X + 27*Y = 3249728140
 osd13 = 48*X + 13*Y = 2991675992
 =>
 osd5 - 27/13*osd13 = 23*X - 27/13*48*X = -76.6923076923077*X = -2963752766.46154
 =>
 X = 38644720.1243731
 Y = (osd5-23*X)/27 = 87440725.0792377
 Y/X = 2.26268232239284 ~= 2.26
 Which means that parity chunks are compressed ~2.26 times worse than data chunks.
 Fine, let's try to optimize for it.
 */
 async function run()
 {
    const all_weights = Object.assign({}, ...Object.values(osd_tree));
    const total_weight = Object.values(all_weights).reduce((a, c) => Number(a) + Number(c), 0);
    const eff = LPOptimizer.pg_list_space_efficiency(prev_pgs, all_weights, 2, 2.26);
    const orig = eff*4.26 / total_weight;
    console.log('Original efficiency was: '+Math.round(orig*10000)/100+' %');
    let prev = await LPOptimizer.optimize_initial({ osd_tree, pg_size: 3, pg_count: 256, parity_space: 2.26 });
    LPOptimizer.print_change_stats(prev);
    let next = await LPOptimizer.optimize_change({ prev_pgs, osd_tree, pg_size: 3, max_combinations: 10000, parity_space: 2.26 });
    LPOptimizer.print_change_stats(next);
 }
 run().catch(console.error);
--- a/mon/test-optimize-undersized.js
+++ b/mon/test-optimize-undersized.js
@ -1,74 +0,0 @@
 // Copyright (c) Vitaliy Filippov, 2019+
 // License: VNPL-1.0 (see README.md for details)
 const LPOptimizer = require('./lp-optimizer.js');
 const crush_tree = [
    { level: 1, children: [
        { level: 2, children: [
            { level: 3, id: 1, size: 3 },
            { level: 3, id: 2, size: 3 },
        ] },
        { level: 2, children: [
            { level: 3, id: 3, size: 3 },
            { level: 3, id: 4, size: 3 },
        ] },
    ] },
    { level: 1, children: [
        { level: 2, children: [
            { level: 3, id: 5, size: 3 },
            { level: 3, id: 6, size: 3 },
        ] },
        { level: 2, children: [
            { level: 3, id: 7, size: 3 },
            { level: 3, id: 8, size: 3 },
        ] },
    ] },
    { level: 1, children: [
        { level: 2, children: [
            { level: 3, id: 9, size: 3 },
            { level: 3, id: 10, size: 3 },
        ] },
        { level: 2, children: [
            { level: 3, id: 11, size: 3 },
            { level: 3, id: 12, size: 3 },
        ] },
    ] },
 ];
 const osd_tree = LPOptimizer.flatten_tree(crush_tree, {}, 1, 3);
 console.log(osd_tree);
 async function run()
 {
    const cur_tree = {};
    console.log('Empty tree:');
    let res = await LPOptimizer.optimize_initial({ osd_tree: cur_tree, pg_size: 3, pg_count: 256 });
    LPOptimizer.print_change_stats(res, false);
    console.log('\nAdding 1st failure domain:');
    cur_tree['dom1'] = osd_tree['dom1'];
    res = await LPOptimizer.optimize_change({ prev_pgs: res.int_pgs, osd_tree: cur_tree, pg_size: 3 });
    LPOptimizer.print_change_stats(res, false);
    console.log('\nAdding 2nd failure domain:');
    cur_tree['dom2'] = osd_tree['dom2'];
    res = await LPOptimizer.optimize_change({ prev_pgs: res.int_pgs, osd_tree: cur_tree, pg_size: 3 });
    LPOptimizer.print_change_stats(res, false);
    console.log('\nAdding 3rd failure domain:');
    cur_tree['dom3'] = osd_tree['dom3'];
    res = await LPOptimizer.optimize_change({ prev_pgs: res.int_pgs, osd_tree: cur_tree, pg_size: 3 });
    LPOptimizer.print_change_stats(res, false);
    console.log('\nRemoving 3rd failure domain:');
    delete cur_tree['dom3'];
    res = await LPOptimizer.optimize_change({ prev_pgs: res.int_pgs, osd_tree: cur_tree, pg_size: 3 });
    LPOptimizer.print_change_stats(res, false);
    console.log('\nRemoving 2nd failure domain:');
    delete cur_tree['dom2'];
    res = await LPOptimizer.optimize_change({ prev_pgs: res.int_pgs, osd_tree: cur_tree, pg_size: 3 });
    LPOptimizer.print_change_stats(res, false);
    console.log('\nRemoving 1st failure domain:');
    delete cur_tree['dom1'];
    res = await LPOptimizer.optimize_change({ prev_pgs: res.int_pgs, osd_tree: cur_tree, pg_size: 3 });
    LPOptimizer.print_change_stats(res, false);
 }
 run().catch(console.error);
--- a/mon/test-optimize.js
+++ b/mon/test-optimize.js
@ -1,115 +0,0 @@
 // Copyright (c) Vitaliy Filippov, 2019+
 // License: VNPL-1.0 (see README.md for details)
 const LPOptimizer = require('./lp-optimizer.js');
 const osd_tree = {
    100: {
        7: 3.63869,
    },
    300: {
        10: 3.46089,
        11: 3.46089,
        12: 3.46089,
    },
    400: {
        1: 3.49309,
        2: 3.49309,
        3: 3.49309,
    },
    500: {
        4: 3.58498,
 //        8: 3.58589,
        9: 3.63869,
    },
    600: {
        5: 3.63869,
        6: 3.63869,
    },
 /*    100: {
        1: 2.72800,
    },
    200: {
        2: 2.72900,
    },
    300: {
        3: 1.87000,
    },
    400: {
        4: 1.87000,
    },
    500: {
        5: 3.63869,
    },*/
 };
 const crush_tree = [
    { level: 1, children: [
        { level: 2, children: [
            { level: 3, id: 1, size: 3 },
            { level: 3, id: 2, size: 2 },
        ] },
        { level: 2, children: [
            { level: 3, id: 3, size: 4 },
            { level: 3, id: 4, size: 4 },
        ] },
    ] },
    { level: 1, children: [
        { level: 2, children: [
            { level: 3, id: 5, size: 4 },
            { level: 3, id: 6, size: 1 },
        ] },
        { level: 2, children: [
            { level: 3, id: 7, size: 3 },
            { level: 3, id: 8, size: 5 },
        ] },
    ] },
    { level: 1, children: [
        { level: 2, children: [
            { level: 3, id: 9, size: 5 },
            { level: 3, id: 10, size: 2 },
        ] },
        { level: 2, children: [
            { level: 3, id: 11, size: 3 },
            { level: 3, id: 12, size: 3 },
        ] },
    ] },
 ];
 async function run()
 {
    let res;
    // Test: add 1 OSD of almost the same size. Ideal data movement could be 1/12 = 8.33%. Actual is ~13%
    // Space efficiency is ~99% in all cases.
    console.log('256 PGs, size=2');
    res = await LPOptimizer.optimize_initial({ osd_tree, pg_size: 2, pg_count: 256 });
    LPOptimizer.print_change_stats(res, false);
    console.log('\nAdding osd.8');
    osd_tree[500][8] = 3.58589;
    res = await LPOptimizer.optimize_change({ prev_pgs: res.int_pgs, osd_tree, pg_size: 2 });
    LPOptimizer.print_change_stats(res, false);
    console.log('\nRemoving osd.8');
    delete osd_tree[500][8];
    res = await LPOptimizer.optimize_change({ prev_pgs: res.int_pgs, osd_tree, pg_size: 2 });
    LPOptimizer.print_change_stats(res, false);
    console.log('\n256 PGs, size=3');
    res = await LPOptimizer.optimize_initial({ osd_tree, pg_size: 3, pg_count: 256 });
    LPOptimizer.print_change_stats(res, false);
    console.log('\nAdding osd.8');
    osd_tree[500][8] = 3.58589;
    res = await LPOptimizer.optimize_change({ prev_pgs: res.int_pgs, osd_tree, pg_size: 3 });
    LPOptimizer.print_change_stats(res, false);
    console.log('\nRemoving osd.8');
    delete osd_tree[500][8];
    res = await LPOptimizer.optimize_change({ prev_pgs: res.int_pgs, osd_tree, pg_size: 3 });
    LPOptimizer.print_change_stats(res, false);
    console.log('\n256 PGs, size=3, failure domain=rack');
    res = await LPOptimizer.optimize_initial({ osd_tree: LPOptimizer.flatten_tree(crush_tree, {}, 1, 3), pg_size: 3, pg_count: 256 });
    LPOptimizer.print_change_stats(res, false);
 }
 run().catch(console.error);
--- a/msgr_receive.cpp
+++ b/msgr_receive.cpp
@ -1,307 +0,0 @@
 // Copyright (c) Vitaliy Filippov, 2019+
 // License: VNPL-1.0 or GNU GPL-2.0+ (see README.md for details)
 #include "messenger.h"
 void osd_messenger_t::read_requests()
 {
    for (int i = 0; i < read_ready_clients.size(); i++)
    {
        int peer_fd = read_ready_clients[i];
        auto & cl = clients[peer_fd];
        if (cl.read_remaining < receive_buffer_size)
        {
            cl.read_iov.iov_base = cl.in_buf;
            cl.read_iov.iov_len = receive_buffer_size;
            cl.read_msg.msg_iov = &cl.read_iov;
            cl.read_msg.msg_iovlen = 1;
        }
        else
        {
            cl.read_iov.iov_base = 0;
            cl.read_iov.iov_len = cl.read_remaining;
            cl.read_msg.msg_iov = cl.recv_list.get_iovec();
            cl.read_msg.msg_iovlen = cl.recv_list.get_size();
        }
        if (ringloop && !use_sync_send_recv)
        {
            io_uring_sqe* sqe = ringloop->get_sqe();
            if (!sqe)
            {
                read_ready_clients.erase(read_ready_clients.begin(), read_ready_clients.begin() + i);
                return;
            }
            ring_data_t* data = ((ring_data_t*)sqe->user_data);
            data->callback = [this, peer_fd](ring_data_t *data) { handle_read(data->res, peer_fd); };
            my_uring_prep_recvmsg(sqe, peer_fd, &cl.read_msg, 0);
        }
        else
        {
            int result = recvmsg(peer_fd, &cl.read_msg, 0);
            if (result < 0)
            {
                result = -errno;
            }
            handle_read(result, peer_fd);
        }
    }
    read_ready_clients.clear();
 }
 bool osd_messenger_t::handle_read(int result, int peer_fd)
 {
    bool ret = false;
    auto cl_it = clients.find(peer_fd);
    if (cl_it != clients.end())
    {
        auto & cl = cl_it->second;
        if (result <= 0 && result != -EAGAIN)
        {
            // this is a client socket, so don't panic on error. just disconnect it
            if (result != 0)
            {
                printf("Client %d socket read error: %d (%s). Disconnecting client\n", peer_fd, -result, strerror(-result));
            }
            stop_client(peer_fd);
            return false;
        }
        if (result == -EAGAIN || result < cl.read_iov.iov_len)
        {
            cl.read_ready--;
            if (cl.read_ready > 0)
                read_ready_clients.push_back(peer_fd);
        }
        else
        {
            read_ready_clients.push_back(peer_fd);
        }
        if (result > 0)
        {
            if (cl.read_iov.iov_base == cl.in_buf)
            {
                // Compose operation(s) from the buffer
                int remain = result;
                void *curbuf = cl.in_buf;
                while (remain > 0)
                {
                    if (!cl.read_op)
                    {
                        cl.read_op = new osd_op_t;
                        cl.read_op->peer_fd = peer_fd;
                        cl.read_op->op_type = OSD_OP_IN;
                        cl.recv_list.push_back(cl.read_op->req.buf, OSD_PACKET_SIZE);
                        cl.read_remaining = OSD_PACKET_SIZE;
                        cl.read_state = CL_READ_HDR;
                    }
                    while (cl.recv_list.done < cl.recv_list.count && remain > 0)
                    {
                        iovec* cur = cl.recv_list.get_iovec();
                        if (cur->iov_len > remain)
                        {
                            memcpy(cur->iov_base, curbuf, remain);
                            cl.read_remaining -= remain;
                            cur->iov_len -= remain;
                            cur->iov_base += remain;
                            remain = 0;
                        }
                        else
                        {
                            memcpy(cur->iov_base, curbuf, cur->iov_len);
                            curbuf += cur->iov_len;
                            cl.read_remaining -= cur->iov_len;
                            remain -= cur->iov_len;
                            cur->iov_len = 0;
                            cl.recv_list.done++;
                        }
                    }
                    if (cl.recv_list.done >= cl.recv_list.count)
                    {
                        if (!handle_finished_read(cl))
                        {
                            goto fin;
                        }
                    }
                }
            }
            else
            {
                // Long data
                cl.read_remaining -= result;
                cl.recv_list.eat(result);
                if (cl.recv_list.done >= cl.recv_list.count)
                {
                    handle_finished_read(cl);
                }
            }
            if (result >= cl.read_iov.iov_len)
            {
                ret = true;
            }
        }
    }
 fin:
    for (auto cb: set_immediate)
    {
        cb();
    }
    set_immediate.clear();
    return ret;
 }
 bool osd_messenger_t::handle_finished_read(osd_client_t & cl)
 {
    cl.recv_list.reset();
    if (cl.read_state == CL_READ_HDR)
    {
        if (cl.read_op->req.hdr.magic == SECONDARY_OSD_REPLY_MAGIC)
            return handle_reply_hdr(&cl);
        else
            handle_op_hdr(&cl);
    }
    else if (cl.read_state == CL_READ_DATA)
    {
        // Operation is ready
        cl.received_ops.push_back(cl.read_op);
        set_immediate.push_back([this, op = cl.read_op]() { exec_op(op); });
        cl.read_op = NULL;
        cl.read_state = 0;
    }
    else if (cl.read_state == CL_READ_REPLY_DATA)
    {
        // Reply is ready
        handle_reply_ready(cl.read_op);
        cl.read_op = NULL;
        cl.read_state = 0;
    }
    else
    {
        assert(0);
    }
    return true;
 }
 void osd_messenger_t::handle_op_hdr(osd_client_t *cl)
 {
    osd_op_t *cur_op = cl->read_op;
    if (cur_op->req.hdr.opcode == OSD_OP_SEC_READ)
    {
        if (cur_op->req.sec_rw.len > 0)
            cur_op->buf = memalign_or_die(MEM_ALIGNMENT, cur_op->req.sec_rw.len);
        cl->read_remaining = 0;
    }
    else if (cur_op->req.hdr.opcode == OSD_OP_SEC_WRITE ||
        cur_op->req.hdr.opcode == OSD_OP_SEC_WRITE_STABLE)
    {
        if (cur_op->req.sec_rw.len > 0)
            cur_op->buf = memalign_or_die(MEM_ALIGNMENT, cur_op->req.sec_rw.len);
        cl->read_remaining = cur_op->req.sec_rw.len;
    }
    else if (cur_op->req.hdr.opcode == OSD_OP_SEC_STABILIZE ||
        cur_op->req.hdr.opcode == OSD_OP_SEC_ROLLBACK)
    {
        if (cur_op->req.sec_stab.len > 0)
            cur_op->buf = memalign_or_die(MEM_ALIGNMENT, cur_op->req.sec_stab.len);
        cl->read_remaining = cur_op->req.sec_stab.len;
    }
    else if (cur_op->req.hdr.opcode == OSD_OP_READ)
    {
        cl->read_remaining = 0;
    }
    else if (cur_op->req.hdr.opcode == OSD_OP_WRITE)
    {
        if (cur_op->req.rw.len > 0)
            cur_op->buf = memalign_or_die(MEM_ALIGNMENT, cur_op->req.rw.len);
        cl->read_remaining = cur_op->req.rw.len;
    }
    if (cl->read_remaining > 0)
    {
        // Read data
        cl->recv_list.push_back(cur_op->buf, cl->read_remaining);
        cl->read_state = CL_READ_DATA;
    }
    else
    {
        // Operation is ready
        cl->received_ops.push_back(cur_op);
        set_immediate.push_back([this, cur_op]() { exec_op(cur_op); });
        cl->read_op = NULL;
        cl->read_state = 0;
    }
 }
 bool osd_messenger_t::handle_reply_hdr(osd_client_t *cl)
 {
    auto req_it = cl->sent_ops.find(cl->read_op->req.hdr.id);
    if (req_it == cl->sent_ops.end())
    {
        // Command out of sync. Drop connection
        printf("Client %d command out of sync: id %lu\n", cl->peer_fd, cl->read_op->req.hdr.id);
        stop_client(cl->peer_fd);
        return false;
    }
    osd_op_t *op = req_it->second;
    memcpy(op->reply.buf, cl->read_op->req.buf, OSD_PACKET_SIZE);
    cl->sent_ops.erase(req_it);
    if ((op->reply.hdr.opcode == OSD_OP_SEC_READ || op->reply.hdr.opcode == OSD_OP_READ) &&
        op->reply.hdr.retval > 0)
    {
        // Read data. In this case we assume that the buffer is preallocated by the caller (!)
        assert(op->iov.count > 0);
        cl->recv_list.append(op->iov);
        delete cl->read_op;
        cl->read_op = op;
        cl->read_state = CL_READ_REPLY_DATA;
        cl->read_remaining = op->reply.hdr.retval;
    }
    else if (op->reply.hdr.opcode == OSD_OP_SEC_LIST && op->reply.hdr.retval > 0)
    {
        assert(!op->iov.count);
        delete cl->read_op;
        cl->read_op = op;
        cl->read_state = CL_READ_REPLY_DATA;
        cl->read_remaining = sizeof(obj_ver_id) * op->reply.hdr.retval;
        op->buf = memalign_or_die(MEM_ALIGNMENT, cl->read_remaining);
        cl->recv_list.push_back(op->buf, cl->read_remaining);
    }
    else if (op->reply.hdr.opcode == OSD_OP_SHOW_CONFIG && op->reply.hdr.retval > 0)
    {
        assert(!op->iov.count);
        delete cl->read_op;
        cl->read_op = op;
        cl->read_state = CL_READ_REPLY_DATA;
        cl->read_remaining = op->reply.hdr.retval;
        op->buf = malloc_or_die(op->reply.hdr.retval);
        cl->recv_list.push_back(op->buf, op->reply.hdr.retval);
    }
    else
    {
        // It's fine to reuse cl->read_op for the next reply
        handle_reply_ready(op);
        cl->recv_list.push_back(cl->read_op->req.buf, OSD_PACKET_SIZE);
        cl->read_remaining = OSD_PACKET_SIZE;
        cl->read_state = CL_READ_HDR;
    }
    return true;
 }
 void osd_messenger_t::handle_reply_ready(osd_op_t *op)
 {
    // Measure subop latency
    timespec tv_end;
    clock_gettime(CLOCK_REALTIME, &tv_end);
    stats.subop_stat_count[op->req.hdr.opcode]++;
    if (!stats.subop_stat_count[op->req.hdr.opcode])
    {
        stats.subop_stat_count[op->req.hdr.opcode]++;
        stats.subop_stat_sum[op->req.hdr.opcode] = 0;
    }
    stats.subop_stat_sum[op->req.hdr.opcode] += (
        (tv_end.tv_sec - op->tv_begin.tv_sec)*1000000 +
        (tv_end.tv_nsec - op->tv_begin.tv_nsec)/1000
    );
    set_immediate.push_back([this, op]()
    {
        // Copy lambda to be unaffected by `delete op`
        std::function<void(osd_op_t*)>(op->callback)(op);
    });
 }
--- a/msgr_send.cpp
+++ b/msgr_send.cpp
@ -1,186 +0,0 @@
 // Copyright (c) Vitaliy Filippov, 2019+
 // License: VNPL-1.0 or GNU GPL-2.0+ (see README.md for details)
 #include "messenger.h"
 void osd_messenger_t::outbox_push(osd_op_t *cur_op)
 {
    assert(cur_op->peer_fd);
    auto & cl = clients.at(cur_op->peer_fd);
    if (cur_op->op_type == OSD_OP_OUT)
    {
        clock_gettime(CLOCK_REALTIME, &cur_op->tv_begin);
    }
    else
    {
        // Check that operation actually belongs to this client
        bool found = false;
        for (auto it = cl.received_ops.begin(); it != cl.received_ops.end(); it++)
        {
            if (*it == cur_op)
            {
                found = true;
                cl.received_ops.erase(it, it+1);
                break;
            }
        }
        if (!found)
        {
            delete cur_op;
            return;
        }
    }
    cl.outbox.push_back(cur_op);
    if (!ringloop)
    {
        while (cl.write_op || cl.outbox.size())
        {
            try_send(cl);
        }
    }
    else if (cl.write_op || cl.outbox.size() > 1 || !try_send(cl))
    {
        if (cl.write_state == 0)
        {
            cl.write_state = CL_WRITE_READY;
            write_ready_clients.push_back(cur_op->peer_fd);
        }
        ringloop->wakeup();
    }
 }
 bool osd_messenger_t::try_send(osd_client_t & cl)
 {
    int peer_fd = cl.peer_fd;
    if (!cl.write_op)
    {
        // pick next command
        cl.write_op = cl.outbox.front();
        cl.outbox.pop_front();
        cl.write_state = CL_WRITE_REPLY;
        if (cl.write_op->op_type == OSD_OP_IN)
        {
            // Measure execution latency
            timespec tv_end;
            clock_gettime(CLOCK_REALTIME, &tv_end);
            stats.op_stat_count[cl.write_op->req.hdr.opcode]++;
            if (!stats.op_stat_count[cl.write_op->req.hdr.opcode])
            {
                stats.op_stat_count[cl.write_op->req.hdr.opcode]++;
                stats.op_stat_sum[cl.write_op->req.hdr.opcode] = 0;
                stats.op_stat_bytes[cl.write_op->req.hdr.opcode] = 0;
            }
            stats.op_stat_sum[cl.write_op->req.hdr.opcode] += (
                (tv_end.tv_sec - cl.write_op->tv_begin.tv_sec)*1000000 +
                (tv_end.tv_nsec - cl.write_op->tv_begin.tv_nsec)/1000
            );
            if (cl.write_op->req.hdr.opcode == OSD_OP_READ ||
                cl.write_op->req.hdr.opcode == OSD_OP_WRITE)
            {
                stats.op_stat_bytes[cl.write_op->req.hdr.opcode] += cl.write_op->req.rw.len;
            }
            else if (cl.write_op->req.hdr.opcode == OSD_OP_SEC_READ ||
                cl.write_op->req.hdr.opcode == OSD_OP_SEC_WRITE ||
                cl.write_op->req.hdr.opcode == OSD_OP_SEC_WRITE_STABLE)
            {
                stats.op_stat_bytes[cl.write_op->req.hdr.opcode] += cl.write_op->req.sec_rw.len;
            }
            cl.send_list.push_back(cl.write_op->reply.buf, OSD_PACKET_SIZE);
            if (cl.write_op->req.hdr.opcode == OSD_OP_READ ||
                cl.write_op->req.hdr.opcode == OSD_OP_SEC_READ ||
                cl.write_op->req.hdr.opcode == OSD_OP_SEC_LIST ||
                cl.write_op->req.hdr.opcode == OSD_OP_SHOW_CONFIG)
            {
                cl.send_list.append(cl.write_op->iov);
            }
        }
        else
        {
            cl.send_list.push_back(cl.write_op->req.buf, OSD_PACKET_SIZE);
            if (cl.write_op->req.hdr.opcode == OSD_OP_WRITE ||
                cl.write_op->req.hdr.opcode == OSD_OP_SEC_WRITE ||
                cl.write_op->req.hdr.opcode == OSD_OP_SEC_WRITE_STABLE ||
                cl.write_op->req.hdr.opcode == OSD_OP_SEC_STABILIZE ||
                cl.write_op->req.hdr.opcode == OSD_OP_SEC_ROLLBACK)
            {
                cl.send_list.append(cl.write_op->iov);
            }
        }
    }
    cl.write_msg.msg_iov = cl.send_list.get_iovec();
    cl.write_msg.msg_iovlen = cl.send_list.get_size();
    if (ringloop && !use_sync_send_recv)
    {
        io_uring_sqe* sqe = ringloop->get_sqe();
        if (!sqe)
        {
            return false;
        }
        ring_data_t* data = ((ring_data_t*)sqe->user_data);
        data->callback = [this, peer_fd](ring_data_t *data) { handle_send(data->res, peer_fd); };
        my_uring_prep_sendmsg(sqe, peer_fd, &cl.write_msg, 0);
    }
    else
    {
        int result = sendmsg(peer_fd, &cl.write_msg, MSG_NOSIGNAL);
        if (result < 0)
        {
            result = -errno;
        }
        handle_send(result, peer_fd);
    }
    return true;
 }
 void osd_messenger_t::send_replies()
 {
    for (int i = 0; i < write_ready_clients.size(); i++)
    {
        int peer_fd = write_ready_clients[i];
        if (!try_send(clients[peer_fd]))
        {
            write_ready_clients.erase(write_ready_clients.begin(), write_ready_clients.begin() + i);
            return;
        }
    }
    write_ready_clients.clear();
 }
 void osd_messenger_t::handle_send(int result, int peer_fd)
 {
    auto cl_it = clients.find(peer_fd);
    if (cl_it != clients.end())
    {
        auto & cl = cl_it->second;
        if (result < 0 && result != -EAGAIN)
        {
            // this is a client socket, so don't panic. just disconnect it
            printf("Client %d socket write error: %d (%s). Disconnecting client\n", peer_fd, -result, strerror(-result));
            stop_client(peer_fd);
            return;
        }
        if (result >= 0)
        {
            cl.send_list.eat(result);
            if (cl.send_list.done >= cl.send_list.count)
            {
                // Done
                cl.send_list.reset();
                if (cl.write_op->op_type == OSD_OP_IN)
                {
                    delete cl.write_op;
                }
                else
                {
                    cl.sent_ops[cl.write_op->req.hdr.id] = cl.write_op;
                }
                cl.write_op = NULL;
                cl.write_state = cl.outbox.size() > 0 ? CL_WRITE_READY : 0;
            }
        }
        if (cl.write_state != 0)
        {
            write_ready_clients.push_back(peer_fd);
        }
    }
 }
--- a/nbd_proxy.cpp
+++ b/nbd_proxy.cpp
@ -1,673 +0,0 @@
 // Copyright (c) Vitaliy Filippov, 2019+
 // License: VNPL-1.0 (see README.md for details)
 // Similar to qemu-nbd, but sets timeout and uses io_uring
 #include <linux/nbd.h>
 #include <sys/ioctl.h>
 #include <sys/socket.h>
 #include <netinet/in.h>
 #include <netinet/tcp.h>
 #include <arpa/inet.h>
 #include <sys/un.h>
 #include <unistd.h>
 #include <fcntl.h>
 #include <signal.h>
 #include "epoll_manager.h"
 #include "cluster_client.h"
 const char *exe_name = NULL;
 class nbd_proxy
 {
 protected:
    uint64_t inode = 0;
    ring_loop_t *ringloop = NULL;
    epoll_manager_t *epmgr = NULL;
    cluster_client_t *cli = NULL;
    ring_consumer_t consumer;
    std::vector<iovec> send_list, next_send_list;
    std::vector<void*> to_free;
    int nbd_fd = -1;
    void *recv_buf = NULL;
    int receive_buffer_size = 9000;
    nbd_request cur_req;
    cluster_op_t *cur_op = NULL;
    void *cur_buf = NULL;
    int cur_left = 0;
    int read_state = 0;
    int read_ready = 0;
    msghdr read_msg = { 0 }, send_msg = { 0 };
    iovec read_iov = { 0 };
 public:
    static json11::Json::object parse_args(int narg, const char *args[])
    {
        json11::Json::object cfg;
        int pos = 0;
        for (int i = 1; i < narg; i++)
        {
            if (!strcmp(args[i], "-h") || !strcmp(args[i], "--help"))
            {
                help();
            }
            else if (args[i][0] == '-' && args[i][1] == '-')
            {
                const char *opt = args[i]+2;
                cfg[opt] = !strcmp(opt, "json") || i == narg-1 ? "1" : args[++i];
            }
            else if (pos == 0)
            {
                cfg["command"] = args[i];
                pos++;
            }
            else if (pos == 1 && (cfg["command"] == "map" || cfg["command"] == "unmap"))
            {
                int n = 0;
                if (sscanf(args[i], "/dev/nbd%d", &n) > 0)
                    cfg["dev_num"] = n;
                else
                    cfg["dev_num"] = args[i];
                pos++;
            }
        }
        return cfg;
    }
    void exec(json11::Json cfg)
    {
        if (cfg["command"] == "map")
        {
            start(cfg);
        }
        else if (cfg["command"] == "unmap")
        {
            if (cfg["dev_num"].is_null())
            {
                fprintf(stderr, "device name or number is missing\n");
                exit(1);
            }
            unmap(cfg["dev_num"].uint64_value());
        }
        else if (cfg["command"] == "list" || cfg["command"] == "list-mapped")
        {
            auto mapped = list_mapped();
            print_mapped(mapped, !cfg["json"].is_null());
        }
        else
        {
            help();
        }
    }
    static void help()
    {
        printf(
            "Vitastor NBD proxy\n"
            "(c) Vitaliy Filippov, 2020 (VNPL-1.0 or GNU GPL 2.0+)\n\n"
            "USAGE:\n"
            "  %s map --etcd_address <etcd_address> --pool <pool> --inode <inode> --size <size in bytes>\n"
            "  %s unmap /dev/nbd0\n"
            "  %s list [--json]\n",
            exe_name, exe_name, exe_name
        );
        exit(0);
    }
    void unmap(int dev_num)
    {
        char path[64] = { 0 };
        sprintf(path, "/dev/nbd%d", dev_num);
        int r, nbd = open(path, O_RDWR);
        if (nbd < 0)
        {
            perror("open");
            exit(1);
        }
        r = ioctl(nbd, NBD_DISCONNECT);
        if (r < 0)
        {
            perror("NBD_DISCONNECT");
            exit(1);
        }
        close(nbd);
    }
    void start(json11::Json cfg)
    {
        // Check options
        if (cfg["etcd_address"].string_value() == "")
        {
            fprintf(stderr, "etcd_address is missing\n");
            exit(1);
        }
        if (!cfg["size"].uint64_value())
        {
            fprintf(stderr, "device size is missing\n");
            exit(1);
        }
        inode = cfg["inode"].uint64_value();
        uint64_t pool = cfg["pool"].uint64_value();
        if (pool)
        {
            inode = (inode & ((1l << (64-POOL_ID_BITS)) - 1)) | (pool << (64-POOL_ID_BITS));
        }
        if (!(inode >> (64-POOL_ID_BITS)))
        {
            fprintf(stderr, "pool is missing\n");
            exit(1);
        }
        // Initialize NBD
        int sockfd[2];
        if (socketpair(AF_UNIX, SOCK_STREAM, 0, sockfd) < 0)
        {
            perror("socketpair");
            exit(1);
        }
        fcntl(sockfd[0], F_SETFL, fcntl(sockfd[0], F_GETFL, 0) | O_NONBLOCK);
        nbd_fd = sockfd[0];
        load_module();
        if (!cfg["dev_num"].is_null())
        {
            if (run_nbd(sockfd, cfg["dev_num"].int64_value(), cfg["size"].uint64_value(), NBD_FLAG_SEND_FLUSH, 30) < 0)
            {
                perror("run_nbd");
                exit(1);
            }
        }
        else
        {
            // Find an unused device
            int i = 0;
            while (true)
            {
                int r = run_nbd(sockfd, i, cfg["size"].uint64_value(), NBD_FLAG_SEND_FLUSH, 30);
                if (r == 0)
                {
                    printf("/dev/nbd%d\n", i);
                    break;
                }
                else if (r == -1 && errno == ENOENT)
                {
                    fprintf(stderr, "No free NBD devices found\n");
                    exit(1);
                }
                else if (r == -2 && errno == EBUSY)
                {
                    i++;
                }
                else
                {
                    printf("%d %d\n", r, errno);
                    perror("run_nbd");
                    exit(1);
                }
            }
        }
        if (cfg["foreground"].is_null())
        {
            daemonize();
        }
        // Create client
        ringloop = new ring_loop_t(512);
        epmgr = new epoll_manager_t(ringloop);
        cli = new cluster_client_t(ringloop, epmgr->tfd, cfg);
        // Initialize read state
        read_state = CL_READ_HDR;
        recv_buf = malloc_or_die(receive_buffer_size);
        cur_buf = &cur_req;
        cur_left = sizeof(nbd_request);
        consumer.loop = [this]()
        {
            submit_read();
            submit_send();
            ringloop->submit();
        };
        ringloop->register_consumer(&consumer);
        // Add FD to epoll
        epmgr->tfd->set_fd_handler(sockfd[0], false, [this](int peer_fd, int epoll_events)
        {
            read_ready++;
            submit_read();
        });
        while (1)
        {
            ringloop->loop();
            ringloop->wait();
        }
    }
    void load_module()
    {
        if (access("/sys/module/nbd", F_OK))
        {
            return;
        }
        int r;
        if ((r = system("modprobe nbd")) != 0)
        {
            if (r < 0)
                perror("Failed to load NBD kernel module");
            else
                fprintf(stderr, "Failed to load NBD kernel module\n");
            exit(1);
        }
    }
    void daemonize()
    {
        if (fork())
            exit(0);
        setsid();
        if (fork())
            exit(0);
        chdir("/");
        close(0);
        close(1);
        close(2);
        open("/dev/null", O_RDONLY);
        open("/dev/null", O_WRONLY);
        open("/dev/null", O_WRONLY);
    }
    json11::Json::object list_mapped()
    {
        const char *self_filename = exe_name;
        for (int i = 0; exe_name[i] != 0; i++)
        {
            if (exe_name[i] == '/')
                self_filename = exe_name+i+1;
        }
        char path[64] = { 0 };
        json11::Json::object mapped;
        int dev_num = -1;
        int pid;
        while (true)
        {
            dev_num++;
            sprintf(path, "/sys/block/nbd%d", dev_num);
            if (access(path, F_OK) != 0)
                break;
            sprintf(path, "/sys/block/nbd%d/pid", dev_num);
            std::string pid_str = read_file(path);
            if (pid_str == "")
                continue;
            if (sscanf(pid_str.c_str(), "%d", &pid) < 1)
            {
                printf("Failed to read pid from /sys/block/nbd%d/pid\n", dev_num);
                continue;
            }
            sprintf(path, "/proc/%d/cmdline", pid);
            std::string cmdline = read_file(path);
            std::vector<const char*> argv;
            int last = 0;
            for (int i = 0; i < cmdline.size(); i++)
            {
                if (cmdline[i] == 0)
                {
                    argv.push_back(cmdline.c_str()+last);
                    last = i+1;
                }
            }
            if (argv.size() > 0)
            {
                const char *pid_filename = argv[0];
                for (int i = 0; argv[0][i] != 0; i++)
                {
                    if (argv[0][i] == '/')
                        pid_filename = argv[0]+i+1;
                }
                if (!strcmp(pid_filename, self_filename))
                {
                    json11::Json::object cfg = nbd_proxy::parse_args(argv.size(), argv.data());
                    if (cfg["command"] == "map")
                    {
                        cfg.erase("command");
                        cfg["pid"] = pid;
                        mapped["/dev/nbd"+std::to_string(dev_num)] = cfg;
                    }
                }
            }
        }
        return mapped;
    }
    void print_mapped(json11::Json mapped, bool json)
    {
        if (json)
        {
            printf("%s\n", mapped.dump().c_str());
        }
        else
        {
            for (auto & dev: mapped.object_items())
            {
                printf("%s\n", dev.first.c_str());
                for (auto & k: dev.second.object_items())
                {
                    printf("%s: %s\n", k.first.c_str(), k.second.string_value().c_str());
                }
                printf("\n");
            }
        }
    }
    std::string read_file(char *path)
    {
        int fd = open(path, O_RDONLY);
        if (fd < 0)
        {
            if (errno == ENOENT)
                return "";
            auto err = "open "+std::string(path);
            perror(err.c_str());
            exit(1);
        }
        std::string r;
        while (true)
        {
            int l = r.size();
            r.resize(l + 1024);
            int rd = read(fd, (void*)(r.c_str() + l), 1024);
            if (rd <= 0)
            {
                r.resize(l);
                break;
            }
            r.resize(l + rd);
        }
        close(fd);
        return r;
    }
 protected:
    int run_nbd(int sockfd[2], int dev_num, uint64_t size, uint64_t flags, unsigned timeout)
    {
        // Check handle size
        assert(sizeof(cur_req.handle) == 8);
        char path[64] = { 0 };
        sprintf(path, "/dev/nbd%d", dev_num);
        int r, nbd = open(path, O_RDWR), qd_fd;
        if (nbd < 0)
        {
            return -1;
        }
        r = ioctl(nbd, NBD_SET_SOCK, sockfd[1]);
        if (r < 0)
        {
            goto end_close;
        }
        r = ioctl(nbd, NBD_SET_BLKSIZE, 4096);
        if (r < 0)
        {
            goto end_unmap;
        }
        r = ioctl(nbd, NBD_SET_SIZE, size);
        if (r < 0)
        {
            goto end_unmap;
        }
        ioctl(nbd, NBD_SET_FLAGS, flags);
        if (timeout >= 0)
        {
            r = ioctl(nbd, NBD_SET_TIMEOUT, (unsigned long)timeout);
            if (r < 0)
            {
                goto end_unmap;
            }
        }
        // Configure request size
        sprintf(path, "/sys/block/nbd%d/queue/max_sectors_kb", dev_num);
        qd_fd = open(path, O_WRONLY);
        if (qd_fd < 0)
        {
            goto end_unmap;
        }
        write(qd_fd, "32768", 5);
        close(qd_fd);
        if (!fork())
        {
            // Run in child
            close(sockfd[0]);
            r = ioctl(nbd, NBD_DO_IT);
            if (r < 0)
            {
                fprintf(stderr, "NBD device terminated with error: %s\n", strerror(errno));
                kill(getppid(), SIGTERM);
            }
            close(sockfd[1]);
            ioctl(nbd, NBD_CLEAR_QUE);
            ioctl(nbd, NBD_CLEAR_SOCK);
            exit(0);
        }
        close(sockfd[1]);
        close(nbd);
        return 0;
    end_close:
        r = errno;
        close(nbd);
        errno = r;
        return -2;
    end_unmap:
        r = errno;
        ioctl(nbd, NBD_CLEAR_SOCK);
        close(nbd);
        errno = r;
        return -3;
    }
    void submit_send()
    {
        if (!send_list.size() || send_msg.msg_iovlen > 0)
        {
            return;
        }
        io_uring_sqe* sqe = ringloop->get_sqe();
        if (!sqe)
        {
            return;
        }
        ring_data_t* data = ((ring_data_t*)sqe->user_data);
        data->callback = [this](ring_data_t *data) { handle_send(data->res); };
        send_msg.msg_iov = send_list.data();
        send_msg.msg_iovlen = send_list.size();
        my_uring_prep_sendmsg(sqe, nbd_fd, &send_msg, MSG_ZEROCOPY);
    }
    void handle_send(int result)
    {
        send_msg.msg_iovlen = 0;
        if (result < 0 && result != -EAGAIN)
        {
            fprintf(stderr, "Socket disconnected: %s\n", strerror(-result));
            exit(1);
        }
        int to_eat = 0;
        while (result > 0 && to_eat < send_list.size())
        {
            if (result >= send_list[to_eat].iov_len)
            {
                free(to_free[to_eat]);
                result -= send_list[to_eat].iov_len;
                to_eat++;
            }
            else
            {
                send_list[to_eat].iov_base += result;
                send_list[to_eat].iov_len -= result;
                break;
            }
        }
        if (to_eat > 0)
        {
            send_list.erase(send_list.begin(), send_list.begin() + to_eat);
            to_free.erase(to_free.begin(), to_free.begin() + to_eat);
        }
        for (int i = 0; i < next_send_list.size(); i++)
        {
            send_list.push_back(next_send_list[i]);
        }
        next_send_list.clear();
        if (send_list.size() > 0)
        {
            ringloop->wakeup();
        }
    }
    void submit_read()
    {
        if (!read_ready || read_msg.msg_iovlen > 0)
        {
            return;
        }
        io_uring_sqe* sqe = ringloop->get_sqe();
        if (!sqe)
        {
            return;
        }
        ring_data_t* data = ((ring_data_t*)sqe->user_data);
        data->callback = [this](ring_data_t *data) { handle_read(data->res); };
        if (cur_left < receive_buffer_size)
        {
            read_iov.iov_base = recv_buf;
            read_iov.iov_len = receive_buffer_size;
        }
        else
        {
            read_iov.iov_base = cur_buf;
            read_iov.iov_len = cur_left;
        }
        read_msg.msg_iov = &read_iov;
        read_msg.msg_iovlen = 1;
        my_uring_prep_recvmsg(sqe, nbd_fd, &read_msg, 0);
    }
    void handle_read(int result)
    {
        read_msg.msg_iovlen = 0;
        if (result < 0 && result != -EAGAIN)
        {
            fprintf(stderr, "Socket disconnected: %s\n", strerror(-result));
            exit(1);
        }
        if (result == -EAGAIN || result < read_iov.iov_len)
        {
            read_ready--;
        }
        if (read_ready > 0)
        {
            ringloop->wakeup();
        }
        void *b = recv_buf;
        while (result > 0)
        {
            if (read_iov.iov_base == recv_buf)
            {
                int inc = result >= cur_left ? cur_left : result;
                memcpy(cur_buf, b, inc);
                cur_left -= inc;
                result -= inc;
                cur_buf += inc;
                b += inc;
            }
            else
            {
                assert(result <= cur_left);
                cur_left -= result;
                result = 0;
            }
            if (cur_left <= 0)
            {
                handle_finished_read();
            }
        }
    }
    void handle_finished_read()
    {
        if (read_state == CL_READ_HDR)
        {
            int req_type = be32toh(cur_req.type);
            if (be32toh(cur_req.magic) != NBD_REQUEST_MAGIC ||
                req_type != NBD_CMD_READ && req_type != NBD_CMD_WRITE && req_type != NBD_CMD_FLUSH)
            {
                printf("Unexpected request: magic=%x type=%x, terminating\n", cur_req.magic, req_type);
                exit(1);
            }
            uint64_t handle = *((uint64_t*)cur_req.handle);
 #ifdef DEBUG
            printf("request %lx +%x %lx\n", be64toh(cur_req.from), be32toh(cur_req.len), handle);
 #endif
            void *buf = NULL;
            cluster_op_t *op = new cluster_op_t;
            if (req_type == NBD_CMD_READ || req_type == NBD_CMD_WRITE)
            {
                op->opcode = req_type == NBD_CMD_READ ? OSD_OP_READ : OSD_OP_WRITE;
                op->inode = inode;
                op->offset = be64toh(cur_req.from);
                op->len = be32toh(cur_req.len);
                buf = malloc_or_die(sizeof(nbd_reply) + op->len);
                op->iov.push_back(buf + sizeof(nbd_reply), op->len);
            }
            else if (req_type == NBD_CMD_FLUSH)
            {
                op->opcode = OSD_OP_SYNC;
                buf = malloc_or_die(sizeof(nbd_reply));
            }
            op->callback = [this, buf, handle](cluster_op_t *op)
            {
 #ifdef DEBUG
                printf("reply %lx e=%d\n", handle, op->retval);
 #endif
                nbd_reply *reply = (nbd_reply*)buf;
                reply->magic = htobe32(NBD_REPLY_MAGIC);
                memcpy(reply->handle, &handle, 8);
                reply->error = htobe32(op->retval < 0 ? -op->retval : 0);
                auto & to_list = send_msg.msg_iovlen > 0 ? next_send_list : send_list;
                if (op->retval < 0 || op->opcode != OSD_OP_READ)
                    to_list.push_back({ .iov_base = buf, .iov_len = sizeof(nbd_reply) });
                else
                    to_list.push_back({ .iov_base = buf, .iov_len = sizeof(nbd_reply) + op->len });
                to_free.push_back(buf);
                delete op;
                ringloop->wakeup();
            };
            if (req_type == NBD_CMD_WRITE)
            {
                cur_op = op;
                cur_buf = buf + sizeof(nbd_reply);
                cur_left = op->len;
                read_state = CL_READ_DATA;
            }
            else
            {
                cur_op = NULL;
                cur_buf = &cur_req;
                cur_left = sizeof(nbd_request);
                read_state = CL_READ_HDR;
                cli->execute(op);
            }
        }
        else
        {
            cli->execute(cur_op);
            cur_op = NULL;
            cur_buf = &cur_req;
            cur_left = sizeof(nbd_request);
            read_state = CL_READ_HDR;
        }
    }
 };
 int main(int narg, const char *args[])
 {
    setvbuf(stdout, NULL, _IONBF, 0);
    setvbuf(stderr, NULL, _IONBF, 0);
    exe_name = args[0];
    nbd_proxy *p = new nbd_proxy();
    p->exec(nbd_proxy::parse_args(narg, args));
    return 0;
 }
--- a/object_id.h
+++ b/object_id.h
@ -1,6 +1,3 @@
 // Copyright (c) Vitaliy Filippov, 2019+
 // License: VNPL-1.0 or GNU GPL-2.0+ (see README.md for details)
 #pragma once
 #include <stdint.h>
--- a/osd.cpp
+++ b/osd.cpp
@ -1,7 +1,5 @@
 // Copyright (c) Vitaliy Filippov, 2019+
 // License: VNPL-1.0 (see README.md for details)
 #include <sys/socket.h>
 #include <sys/epoll.h>
 #include <sys/poll.h>
 #include <netinet/in.h>
 #include <netinet/tcp.h>
@ -9,100 +7,71 @@
 #include "osd.h"
 static const char* osd_op_names[] = {
    "",
    "read",
    "write",
    "sync",
    "stabilize",
    "rollback",
    "delete",
    "sync_stab_all",
    "list",
    "show_config",
    "primary_read",
    "primary_write",
    "primary_sync",
 };
 osd_t::osd_t(blockstore_config_t & config, blockstore_t *bs, ring_loop_t *ringloop)
 {
    this->config = config;
    this->bs = bs;
    this->ringloop = ringloop;
-
+    this->tick_tfd = new timerfd_interval(ringloop, 3, [this]()
    {
        for (int i = 0; i <= OSD_OP_MAX; i++)
        {
            if (op_stat_count[i] != 0)
            {
                printf("avg latency for op %d (%s): %ld us\n", i, osd_op_names[i], op_stat_sum[i]/op_stat_count[i]);
                op_stat_count[i] = 0;
                op_stat_sum[i] = 0;
            }
        }
        for (int i = 0; i <= OSD_OP_MAX; i++)
        {
            if (subop_stat_count[i] != 0)
            {
                printf("avg latency for subop %d (%s): %ld us\n", i, osd_op_names[i], subop_stat_sum[i]/subop_stat_count[i]);
                subop_stat_count[i] = 0;
                subop_stat_sum[i] = 0;
            }
        }
        if (send_stat_count != 0)
        {
            printf("avg latency to send stabilize subop: %ld us\n", send_stat_sum/send_stat_count);
            send_stat_count = 0;
            send_stat_sum = 0;
        }
    });
    this->bs_block_size = bs->get_block_size();
    // FIXME: use bitmap granularity instead
    this->bs_disk_alignment = bs->get_disk_alignment();
    parse_config(config);
    epmgr = new epoll_manager_t(ringloop);
    this->tfd = epmgr->tfd;
    this->tfd->set_timer(print_stats_interval*1000, true, [this](int timer_id)
    {
        print_stats();
    });
    c_cli.tfd = this->tfd;
    c_cli.ringloop = this->ringloop;
    c_cli.exec_op = [this](osd_op_t *op) { exec_op(op); };
    c_cli.repeer_pgs = [this](osd_num_t peer_osd) { repeer_pgs(peer_osd); };
    init_cluster();
    consumer.loop = [this]() { loop(); };
    ringloop->register_consumer(&consumer);
 }
 osd_t::~osd_t()
 {
    ringloop->unregister_consumer(&consumer);
    delete epmgr;
    close(listen_fd);
 }
 void osd_t::parse_config(blockstore_config_t & config)
 {
    // Initial startup configuration
    json11::Json json_config = json11::Json(config);
    st_cli.parse_config(json_config);
    etcd_report_interval = strtoull(config["etcd_report_interval"].c_str(), NULL, 10);
    if (etcd_report_interval <= 0)
        etcd_report_interval = 30;
    osd_num = strtoull(config["osd_num"].c_str(), NULL, 10);
    if (!osd_num)
        throw std::runtime_error("osd_num is required in the configuration");
    c_cli.osd_num = osd_num;
    run_primary = config["run_primary"] != "false" && config["run_primary"] != "0" && config["run_primary"] != "no";
    // Cluster configuration
    bind_address = config["bind_address"];
    if (bind_address == "")
        bind_address = "0.0.0.0";
-    bind_port = stoull_full(config["bind_port"]);
+    bind_port = strtoull(config["bind_port"].c_str(), NULL, 10);
-    if (bind_port <= 0 || bind_port > 65535)
+    if (!bind_port || bind_port > 65535)
-        bind_port = 0;
+        bind_port = 11203;
-    if (config["immediate_commit"] == "all")
+    osd_num = strtoull(config["osd_num"].c_str(), NULL, 10);
-        immediate_commit = IMMEDIATE_ALL;
+    if (!osd_num)
-    else if (config["immediate_commit"] == "small")
+        throw std::runtime_error("osd_num is required in the configuration");
-        immediate_commit = IMMEDIATE_SMALL;
+    run_primary = config["run_primary"] == "true" || config["run_primary"] == "1" || config["run_primary"] == "yes";
-    if (config.find("autosync_interval") != config.end())
+    if (run_primary)
-    {
+        init_primary();
        autosync_interval = strtoull(config["autosync_interval"].c_str(), NULL, 10);
        if (autosync_interval > MAX_AUTOSYNC_INTERVAL)
            autosync_interval = DEFAULT_AUTOSYNC_INTERVAL;
    }
    if (config.find("client_queue_depth") != config.end())
    {
        client_queue_depth = strtoull(config["client_queue_depth"].c_str(), NULL, 10);
        if (client_queue_depth < 128)
            client_queue_depth = 128;
    }
    recovery_queue_depth = strtoull(config["recovery_queue_depth"].c_str(), NULL, 10);
    if (recovery_queue_depth < 1 || recovery_queue_depth > MAX_RECOVERY_QUEUE)
        recovery_queue_depth = DEFAULT_RECOVERY_QUEUE;
    if (config["readonly"] == "true" || config["readonly"] == "1" || config["readonly"] == "yes")
        readonly = true;
    print_stats_interval = strtoull(config["print_stats_interval"].c_str(), NULL, 10);
    if (!print_stats_interval)
        print_stats_interval = 3;
    c_cli.peer_connect_interval = strtoull(config["peer_connect_interval"].c_str(), NULL, 10);
    if (!c_cli.peer_connect_interval)
        c_cli.peer_connect_interval = DEFAULT_PEER_CONNECT_INTERVAL;
    c_cli.peer_connect_timeout = strtoull(config["peer_connect_timeout"].c_str(), NULL, 10);
    if (!c_cli.peer_connect_timeout)
        c_cli.peer_connect_timeout = DEFAULT_PEER_CONNECT_TIMEOUT;
    log_level = strtoull(config["log_level"].c_str(), NULL, 10);
    c_cli.log_level = log_level;
 }
 void osd_t::bind_socket()
 {
    listen_fd = socket(AF_INET, SOCK_STREAM, 0);
    if (listen_fd < 0)
    {
@ -119,27 +88,13 @@ void osd_t::bind_socket()
        throw std::runtime_error("bind address "+bind_address+(r == 0 ? " is not valid" : ": no ipv4 support"));
    }
    addr.sin_family = AF_INET;
    addr.sin_port = htons(bind_port);
    if (bind(listen_fd, (sockaddr*)&addr, sizeof(addr)) < 0)
    {
        close(listen_fd);
        throw std::runtime_error(std::string("bind: ") + strerror(errno));
    }
    if (bind_port == 0)
    {
        socklen_t len = sizeof(addr);
        if (getsockname(listen_fd, (sockaddr *)&addr, &len) == -1)
        {
            close(listen_fd);
            throw std::runtime_error(std::string("getsockname: ") + strerror(errno));
        }
        listening_port = ntohs(addr.sin_port);
    }
    else
    {
        listening_port = bind_port;
    }
    if (listen(listen_fd, listen_backlog) < 0)
    {
@ -149,10 +104,56 @@ void osd_t::bind_socket()
    fcntl(listen_fd, F_SETFL, fcntl(listen_fd, F_GETFL, 0) | O_NONBLOCK);
-    epmgr->set_fd_handler(listen_fd, false, [this](int fd, int events)
+    epoll_fd = epoll_create(1);
    if (epoll_fd < 0)
    {
-        c_cli.accept_connections(listen_fd);
+        close(listen_fd);
-    });
+        throw std::runtime_error(std::string("epoll_create: ") + strerror(errno));
    }
    epoll_fd_index = ringloop->register_fd(epoll_fd);
    epoll_event ev;
    ev.data.fd = listen_fd;
    ev.events = EPOLLIN | EPOLLET;
    if (epoll_ctl(epoll_fd, EPOLL_CTL_ADD, listen_fd, &ev) < 0)
    {
        close(listen_fd);
        close(epoll_fd);
        throw std::runtime_error(std::string("epoll_ctl: ") + strerror(errno));
    }
    consumer.loop = [this]() { loop(); };
    ringloop->register_consumer(consumer);
 }
 osd_t::~osd_t()
 {
    delete tick_tfd;
    ringloop->unregister_consumer(consumer);
    close(epoll_fd);
    close(listen_fd);
 }
 osd_op_t::~osd_op_t()
 {
    if (bs_op)
    {
        delete bs_op;
    }
    if (op_data)
    {
        free(op_data);
    }
    if (rmw_buf)
    {
        free(rmw_buf);
    }
    if (buf)
    {
        // Note: reusing osd_op_t WILL currently lead to memory leaks
        // So we don't reuse it, but free it every time
        free(buf);
    }
 }
 bool osd_t::shutdown()
@ -167,12 +168,191 @@ bool osd_t::shutdown()
 void osd_t::loop()
 {
    if (!wait_state)
    {
        handle_epoll_events();
        wait_state = 1;
    }
    handle_peers();
-    c_cli.read_requests();
+    read_requests();
-    c_cli.send_replies();
+    send_replies();
    ringloop->submit();
 }
 void osd_t::handle_epoll_events()
 {
    io_uring_sqe *sqe = ringloop->get_sqe();
    if (!sqe)
    {
        throw std::runtime_error("can't get SQE, will fall out of sync with EPOLLET");
    }
    ring_data_t *data = ((ring_data_t*)sqe->user_data);
    data->allow_cancel = true;
    my_uring_prep_poll_add(sqe, epoll_fd_index, POLLIN);
    sqe->flags |= IOSQE_FIXED_FILE;
    data->callback = [this](ring_data_t *data)
    {
        if (data->res < 0 && data->res != -ECANCELED)
        {
            throw std::runtime_error(std::string("epoll failed: ") + strerror(-data->res));
        }
        handle_epoll_events();
    };
    ringloop->submit();
    // FIXME With SQ thread we have no guarantee that epoll request will be submitted right here...
    int nfds;
    epoll_event events[MAX_EPOLL_EVENTS];
 restart:
    nfds = epoll_wait(epoll_fd, events, MAX_EPOLL_EVENTS, 0);
    for (int i = 0; i < nfds; i++)
    {
        if (events[i].data.fd == listen_fd)
        {
            // Accept new connections
            sockaddr_in addr;
            socklen_t peer_addr_size = sizeof(addr);
            int peer_fd;
            while ((peer_fd = accept(listen_fd, (sockaddr*)&addr, &peer_addr_size)) >= 0)
            {
                char peer_str[256];
                printf("osd: new client %d: connection from %s port %d\n", peer_fd, inet_ntop(AF_INET, &addr.sin_addr, peer_str, 256), ntohs(addr.sin_port));
                fcntl(peer_fd, F_SETFL, fcntl(listen_fd, F_GETFL, 0) | O_NONBLOCK);
                int one = 1;
                setsockopt(peer_fd, SOL_TCP, TCP_NODELAY, &one, sizeof(one));
                clients[peer_fd] = {
                    .peer_addr = addr,
                    .peer_port = ntohs(addr.sin_port),
                    .peer_fd = peer_fd,
                    .peer_fd_index = ringloop->register_fd(peer_fd),
                    .peer_state = PEER_CONNECTED,
                };
                // Add FD to epoll
                epoll_event ev;
                ev.data.fd = peer_fd;
                ev.events = EPOLLIN | EPOLLRDHUP | EPOLLET;
                if (epoll_ctl(epoll_fd, EPOLL_CTL_ADD, peer_fd, &ev) < 0)
                {
                    throw std::runtime_error(std::string("epoll_ctl: ") + strerror(errno));
                }
                // Try to accept next connection
                peer_addr_size = sizeof(addr);
            }
            if (peer_fd == -1 && errno != EAGAIN)
            {
                throw std::runtime_error(std::string("accept: ") + strerror(errno));
            }
        }
        else
        {
            auto & cl = clients[events[i].data.fd];
            if (cl.peer_state == PEER_CONNECTING)
            {
                // Either OUT (connected) or HUP
                handle_connect_result(cl.peer_fd);
            }
            else if (events[i].events & EPOLLRDHUP)
            {
                // Stop client
                printf("osd: client %d disconnected\n", cl.peer_fd);
                stop_client(cl.peer_fd);
            }
            else
            {
                // Mark client as ready (i.e. some data is available)
                cl.read_ready++;
                if (cl.read_ready == 1)
                {
                    read_ready_clients.push_back(cl.peer_fd);
                    ringloop->wakeup();
                }
            }
        }
    }
    if (nfds > 0)
    {
        goto restart;
    }
 }
 void osd_t::cancel_osd_ops(osd_client_t & cl)
 {
    for (auto p: cl.sent_ops)
    {
        cancel_op(p.second);
    }
    cl.sent_ops.clear();
    for (auto op: cl.outbox)
    {
        cancel_op(op);
    }
    cl.outbox.clear();
    if (cl.write_op)
    {
        cancel_op(cl.write_op);
        cl.write_op = NULL;
    }
 }
 void osd_t::cancel_op(osd_op_t *op)
 {
    if (op->op_type == OSD_OP_OUT)
    {
        op->reply.hdr.magic = SECONDARY_OSD_REPLY_MAGIC;
        op->reply.hdr.id = op->req.hdr.id;
        op->reply.hdr.opcode = op->req.hdr.opcode;
        op->reply.hdr.retval = -EPIPE;
        op->callback(op);
    }
    else
    {
        delete op;
    }
 }
 void osd_t::stop_client(int peer_fd)
 {
    auto it = clients.find(peer_fd);
    if (it == clients.end())
    {
        return;
    }
    auto & cl = it->second;
    if (epoll_ctl(epoll_fd, EPOLL_CTL_DEL, peer_fd, NULL) < 0)
    {
        throw std::runtime_error(std::string("epoll_ctl: ") + strerror(errno));
    }
    if (cl.osd_num)
    {
        // Cancel outbound operations
        cancel_osd_ops(cl);
        osd_peer_fds.erase(cl.osd_num);
        repeer_pgs(cl.osd_num, false);
        peering_state |= OSD_PEERING_PEERS;
    }
    if (cl.read_op)
    {
        delete cl.read_op;
    }
    for (auto rit = read_ready_clients.begin(); rit != read_ready_clients.end(); rit++)
    {
        if (*rit == peer_fd)
        {
            read_ready_clients.erase(rit);
            break;
        }
    }
    for (auto wit = write_ready_clients.begin(); wit != write_ready_clients.end(); wit++)
    {
        if (*wit == peer_fd)
        {
            write_ready_clients.erase(wit);
            break;
        }
    }
    clients.erase(it);
    close(peer_fd);
 }
 void osd_t::exec_op(osd_op_t *cur_op)
 {
    clock_gettime(CLOCK_REALTIME, &cur_op->tv_begin);
@ -182,36 +362,23 @@ void osd_t::exec_op(osd_op_t *cur_op)
        delete cur_op;
        return;
    }
-    inflight_ops++;
+    cur_op->send_list.push_back(cur_op->reply.buf, OSD_PACKET_SIZE);
    if (cur_op->req.hdr.magic != SECONDARY_OSD_OP_MAGIC ||
        cur_op->req.hdr.opcode < OSD_OP_MIN || cur_op->req.hdr.opcode > OSD_OP_MAX ||
-        ((cur_op->req.hdr.opcode == OSD_OP_SEC_READ ||
+        (cur_op->req.hdr.opcode == OSD_OP_SECONDARY_READ || cur_op->req.hdr.opcode == OSD_OP_SECONDARY_WRITE) &&
-            cur_op->req.hdr.opcode == OSD_OP_SEC_WRITE ||
+        (cur_op->req.sec_rw.len > OSD_RW_MAX || cur_op->req.sec_rw.len % OSD_RW_ALIGN || cur_op->req.sec_rw.offset % OSD_RW_ALIGN) ||
-            cur_op->req.hdr.opcode == OSD_OP_SEC_WRITE_STABLE) &&
+        (cur_op->req.hdr.opcode == OSD_OP_READ || cur_op->req.hdr.opcode == OSD_OP_WRITE) &&
-            (cur_op->req.sec_rw.len > OSD_RW_MAX ||
+        (cur_op->req.rw.len > OSD_RW_MAX || cur_op->req.rw.len % OSD_RW_ALIGN || cur_op->req.rw.offset % OSD_RW_ALIGN))
            cur_op->req.sec_rw.len % bs_disk_alignment ||
            cur_op->req.sec_rw.offset % bs_disk_alignment)) ||
        ((cur_op->req.hdr.opcode == OSD_OP_READ ||
            cur_op->req.hdr.opcode == OSD_OP_WRITE ||
            cur_op->req.hdr.opcode == OSD_OP_DELETE) &&
            (cur_op->req.rw.len > OSD_RW_MAX ||
            cur_op->req.rw.len % bs_disk_alignment ||
            cur_op->req.rw.offset % bs_disk_alignment)))
    {
        // Bad command
-        finish_op(cur_op, -EINVAL);
+        cur_op->reply.hdr.magic = SECONDARY_OSD_REPLY_MAGIC;
-        return;
+        cur_op->reply.hdr.id = cur_op->req.hdr.id;
-    }
+        cur_op->reply.hdr.opcode = cur_op->req.hdr.opcode;
-    if (readonly &&
+        cur_op->reply.hdr.retval = -EINVAL;
-        cur_op->req.hdr.opcode != OSD_OP_SEC_READ &&
+        outbox_push(this->clients[cur_op->peer_fd], cur_op);
        cur_op->req.hdr.opcode != OSD_OP_SEC_LIST &&
        cur_op->req.hdr.opcode != OSD_OP_READ &&
        cur_op->req.hdr.opcode != OSD_OP_SHOW_CONFIG)
    {
        // Readonly mode
        finish_op(cur_op, -EROFS);
        return;
    }
    inflight_ops++;
    if (cur_op->req.hdr.opcode == OSD_OP_TEST_SYNC_STAB_ALL)
    {
        exec_sync_stab_all(cur_op);
@ -232,84 +399,8 @@ void osd_t::exec_op(osd_op_t *cur_op)
    {
        continue_primary_sync(cur_op);
    }
    else if (cur_op->req.hdr.opcode == OSD_OP_DELETE)
    {
        continue_primary_del(cur_op);
    }
    else
    {
        exec_secondary(cur_op);
    }
 }
 void osd_t::reset_stats()
 {
    c_cli.stats = { 0 };
    prev_stats = { 0 };
    memset(recovery_stat_count, 0, sizeof(recovery_stat_count));
    memset(recovery_stat_bytes, 0, sizeof(recovery_stat_bytes));
 }
 void osd_t::print_stats()
 {
    for (int i = 0; i <= OSD_OP_MAX; i++)
    {
        if (c_cli.stats.op_stat_count[i] != prev_stats.op_stat_count[i])
        {
            uint64_t avg = (c_cli.stats.op_stat_sum[i] - prev_stats.op_stat_sum[i])/(c_cli.stats.op_stat_count[i] - prev_stats.op_stat_count[i]);
            uint64_t bw = (c_cli.stats.op_stat_bytes[i] - prev_stats.op_stat_bytes[i]) / print_stats_interval;
            if (c_cli.stats.op_stat_bytes[i] != 0)
            {
                printf(
                    "[OSD %lu] avg latency for op %d (%s): %lu us, B/W: %.2f %s\n", osd_num, i, osd_op_names[i], avg,
                    (bw > 1024*1024*1024 ? bw/1024.0/1024/1024 : (bw > 1024*1024 ? bw/1024.0/1024 : bw/1024.0)),
                    (bw > 1024*1024*1024 ? "GB/s" : (bw > 1024*1024 ? "MB/s" : "KB/s"))
                );
            }
            else
            {
                printf("[OSD %lu] avg latency for op %d (%s): %lu us\n", osd_num, i, osd_op_names[i], avg);
            }
            prev_stats.op_stat_count[i] = c_cli.stats.op_stat_count[i];
            prev_stats.op_stat_sum[i] = c_cli.stats.op_stat_sum[i];
            prev_stats.op_stat_bytes[i] = c_cli.stats.op_stat_bytes[i];
        }
    }
    for (int i = 0; i <= OSD_OP_MAX; i++)
    {
        if (c_cli.stats.subop_stat_count[i] != prev_stats.subop_stat_count[i])
        {
            uint64_t avg = (c_cli.stats.subop_stat_sum[i] - prev_stats.subop_stat_sum[i])/(c_cli.stats.subop_stat_count[i] - prev_stats.subop_stat_count[i]);
            printf("[OSD %lu] avg latency for subop %d (%s): %ld us\n", osd_num, i, osd_op_names[i], avg);
            prev_stats.subop_stat_count[i] = c_cli.stats.subop_stat_count[i];
            prev_stats.subop_stat_sum[i] = c_cli.stats.subop_stat_sum[i];
        }
    }
    for (int i = 0; i < 2; i++)
    {
        if (recovery_stat_count[0][i] != recovery_stat_count[1][i])
        {
            uint64_t bw = (recovery_stat_bytes[0][i] - recovery_stat_bytes[1][i]) / print_stats_interval;
            printf(
                "[OSD %lu] %s recovery: %.1f op/s, B/W: %.2f %s\n", osd_num, recovery_stat_names[i],
                (recovery_stat_count[0][i] - recovery_stat_count[1][i]) * 1.0 / print_stats_interval,
                (bw > 1024*1024*1024 ? bw/1024.0/1024/1024 : (bw > 1024*1024 ? bw/1024.0/1024 : bw/1024.0)),
                (bw > 1024*1024*1024 ? "GB/s" : (bw > 1024*1024 ? "MB/s" : "KB/s"))
            );
            recovery_stat_count[1][i] = recovery_stat_count[0][i];
            recovery_stat_bytes[1][i] = recovery_stat_bytes[0][i];
        }
    }
    if (incomplete_objects > 0)
    {
        printf("[OSD %lu] %lu object(s) incomplete\n", osd_num, incomplete_objects);
    }
    if (degraded_objects > 0)
    {
        printf("[OSD %lu] %lu object(s) degraded\n", osd_num, degraded_objects);
    }
    if (misplaced_objects > 0)
    {
        printf("[OSD %lu] %lu object(s) misplaced\n", osd_num, misplaced_objects);
    }
 }
--- a/osd.h
+++ b/osd.h
@ -1,6 +1,3 @@
 // Copyright (c) Vitaliy Filippov, 2019+
 // License: VNPL-1.0 (see README.md for details)
 #pragma once
 #include <sys/types.h>
@ -18,86 +15,171 @@
 #include "blockstore.h"
 #include "ringloop.h"
-#include "timerfd_manager.h"
+#include "timerfd_interval.h"
-#include "epoll_manager.h"
+#include "osd_ops.h"
 #include "osd_peering_pg.h"
 #include "messenger.h"
 #include "etcd_state_client.h"
-#define OSD_LOADING_PGS 0x01
+#include "sparsepp/sparsepp/spp.h"
 #define OSD_PEERING_PGS 0x04
 #define OSD_FLUSHING_PGS 0x08
 #define OSD_RECOVERING 0x10
-#define IMMEDIATE_NONE 0
+#define OSD_OP_IN 0
-#define IMMEDIATE_SMALL 1
+#define OSD_OP_OUT 1
 #define IMMEDIATE_ALL 2
-#define MAX_AUTOSYNC_INTERVAL 3600
+#define CL_READ_OP 1
-#define DEFAULT_AUTOSYNC_INTERVAL 5
+#define CL_READ_DATA 2
-#define MAX_RECOVERY_QUEUE 2048
+#define CL_READ_REPLY_DATA 3
-#define DEFAULT_RECOVERY_QUEUE 4
+#define CL_WRITE_READY 1
 #define CL_WRITE_REPLY 2
 #define MAX_EPOLL_EVENTS 64
 #define OSD_OP_INLINE_BUF_COUNT 16
 #define PEER_CONNECTING 1
 #define PEER_CONNECTED 2
 #define OSD_PEERING_PEERS 1
 #define OSD_PEERING_PGS 2
 //#define OSD_STUB
 struct osd_op_buf_list_t
 {
    int count = 0, alloc = 0, sent = 0;
    iovec *buf = NULL;
    iovec inline_buf[OSD_OP_INLINE_BUF_COUNT];
    ~osd_op_buf_list_t()
    {
        if (buf && buf != inline_buf)
        {
            free(buf);
        }
    }
    inline iovec* get_iovec()
    {
        return (buf ? buf : inline_buf) + sent;
    }
    inline int get_size()
    {
        return count - sent;
    }
    inline void push_back(void *nbuf, size_t len)
    {
        if (count >= alloc)
        {
            if (!alloc)
            {
                alloc = OSD_OP_INLINE_BUF_COUNT;
                buf = inline_buf;
            }
            else if (buf == inline_buf)
            {
                int old = alloc;
                alloc = ((alloc/16)*16 + 1);
                buf = (iovec*)malloc(sizeof(iovec) * alloc);
                memcpy(buf, inline_buf, sizeof(iovec)*old);
            }
            else
            {
                alloc = ((alloc/16)*16 + 1);
                buf = (iovec*)realloc(buf, sizeof(iovec) * alloc);
            }
        }
        buf[count++] = { .iov_base = nbuf, .iov_len = len };
    }
 };
 struct osd_primary_op_data_t;
 struct osd_op_t
 {
    timespec tv_begin;
    timespec tv_send;
    int op_type = OSD_OP_IN;
    int peer_fd;
    osd_any_op_t req;
    osd_any_reply_t reply;
    blockstore_op_t *bs_op = NULL;
    void *buf = NULL;
    void *rmw_buf = NULL;
    osd_primary_op_data_t* op_data = NULL;
    std::function<void(osd_op_t*)> callback;
    osd_op_buf_list_t send_list;
    ~osd_op_t();
 };
 struct osd_peer_def_t
 {
    osd_num_t osd_num = 0;
    std::string addr;
    int port = 0;
    time_t last_connect_attempt = 0;
 };
 struct osd_client_t
 {
    sockaddr_in peer_addr;
    int peer_port;
    int peer_fd, peer_fd_index;
    int peer_state;
    std::function<void(osd_num_t, int)> connect_callback;
    osd_num_t osd_num = 0;
    // Read state
    int read_ready = 0;
    osd_op_t *read_op = NULL;
    int read_reply_id = 0;
    iovec read_iov;
    msghdr read_msg;
    void *read_buf = NULL;
    int read_remaining = 0;
    int read_state = 0;
    // Outbound operations sent to this client (which is probably an OSD peer)
    std::map<int, osd_op_t*> sent_ops;
    // Outbound messages (replies or requests)
    std::deque<osd_op_t*> outbox;
    // PGs dirtied by this client's primary-writes
    std::set<pg_num_t> dirty_pgs;
    // Write state
    osd_op_t *write_op = NULL;
    msghdr write_msg;
    int write_state = 0;
 };
 struct osd_rmw_stripe_t;
 struct osd_object_id_t
 {
    osd_num_t osd_num;
    object_id oid;
 };
 struct osd_recovery_op_t
 {
    int st = 0;
    bool degraded = false;
    object_id oid = { 0 };
    osd_op_t *osd_op = NULL;
 };
 class osd_t
 {
    // config
    blockstore_config_t config;
    int etcd_report_interval = 30;
    bool readonly = false;
    osd_num_t osd_num = 1; // OSD numbers start with 1
    bool run_primary = false;
    std::vector<osd_peer_def_t> peers;
    blockstore_config_t config;
    std::string bind_address;
    int bind_port, listen_backlog;
    // FIXME: Implement client queue depth limit
    int client_queue_depth = 128;
    bool allow_test_ops = true;
    int print_stats_interval = 3;
    int immediate_commit = IMMEDIATE_NONE;
    int autosync_interval = DEFAULT_AUTOSYNC_INTERVAL; // sync every 5 seconds
    int recovery_queue_depth = DEFAULT_RECOVERY_QUEUE;
    int log_level = 0;
-    // cluster state
+    // peer OSDs
-    etcd_state_client_t st_cli;
+    std::map<uint64_t, int> osd_peer_fds;
-    osd_messenger_t c_cli;
+    std::vector<pg_t> pgs;
    int etcd_failed_attempts = 0;
    std::string etcd_lease_id;
    json11::Json self_state;
    bool loading_peer_config = false;
    std::set<pool_pg_num_t> pg_state_dirty;
    bool pg_config_applied = false;
    bool etcd_reporting_pg_state = false;
    bool etcd_reporting_stats = false;
    // peers and PGs
    std::map<pool_id_t, pg_num_t> pg_counts;
    std::map<pool_pg_num_t, pg_t> pgs;
    std::set<pool_pg_num_t> dirty_pgs;
    std::set<osd_num_t> dirty_osds;
    uint64_t misplaced_objects = 0, degraded_objects = 0, incomplete_objects = 0;
    int peering_state = 0;
-    std::map<object_id, osd_recovery_op_t> recovery_ops;
+    unsigned pg_count = 0;
-    osd_op_t *autosync_op = NULL;
+    uint64_t next_subop_id = 1;
    // Unstable writes
    std::map<osd_object_id_t, uint64_t> unstable_writes;
@ -109,69 +191,53 @@ class osd_t
    int inflight_ops = 0;
    blockstore_t *bs;
    uint32_t bs_block_size, bs_disk_alignment;
    uint64_t parity_block_size = 4*1024*1024; // 4 MB by default
    ring_loop_t *ringloop;
-    timerfd_manager_t *tfd = NULL;
+    timerfd_interval *tick_tfd;
    epoll_manager_t *epmgr = NULL;
-    int listening_port = 0;
+    int wait_state = 0;
    int epoll_fd = 0, epoll_fd_index = -1;
    int listen_fd = 0;
    ring_consumer_t consumer;
-    // op statistics
+    std::unordered_map<int,osd_client_t> clients;
-    osd_op_stats_t prev_stats;
+    std::vector<int> read_ready_clients;
-    const char* recovery_stat_names[2] = { "degraded", "misplaced" };
+    std::vector<int> write_ready_clients;
-    uint64_t recovery_stat_count[2][2] = { 0 };
+    uint64_t op_stat_sum[OSD_OP_MAX+1] = { 0 };
-    uint64_t recovery_stat_bytes[2][2] = { 0 };
+    uint64_t op_stat_count[OSD_OP_MAX+1] = { 0 };
    uint64_t subop_stat_sum[OSD_OP_MAX+1] = { 0 };
    uint64_t subop_stat_count[OSD_OP_MAX+1] = { 0 };
    uint64_t send_stat_sum = 0;
    uint64_t send_stat_count = 0;
-    // cluster connection
+    // methods
    void parse_config(blockstore_config_t & config);
    void init_cluster();
    void on_change_osd_state_hook(osd_num_t peer_osd);
    void on_change_pg_history_hook(pool_id_t pool_id, pg_num_t pg_num);
    void on_change_etcd_state_hook(json11::Json::object & changes);
    void on_load_config_hook(json11::Json::object & changes);
    json11::Json on_load_pgs_checks_hook();
    void on_load_pgs_hook(bool success);
    void bind_socket();
    void acquire_lease();
    json11::Json get_osd_state();
    void create_osd_state();
    void renew_lease();
    void print_stats();
    void reset_stats();
    json11::Json get_statistics();
    void report_statistics();
    void report_pg_state(pg_t & pg);
    void report_pg_states();
    void apply_pg_count();
    void apply_pg_config();
    // event loop, socket read/write
    void loop();
    void handle_epoll_events();
    void read_requests();
    void handle_read(ring_data_t *data, int peer_fd);
    void handle_op_hdr(osd_client_t *cl);
    void handle_reply_hdr(osd_client_t *cl);
    bool try_send(osd_client_t & cl);
    void send_replies();
    void handle_send(ring_data_t *data, int peer_fd);
    void outbox_push(osd_client_t & cl, osd_op_t *op);
    // peer handling (primary OSD logic)
-    void parse_test_peer(std::string peer);
+    void connect_peer(osd_num_t osd_num, const char *peer_host, int peer_port, std::function<void(osd_num_t, int)> callback);
    void handle_connect_result(int peer_fd);
    void cancel_osd_ops(osd_client_t & cl);
    void cancel_op(osd_op_t *op);
    void stop_client(int peer_fd);
    osd_peer_def_t parse_peer(std::string peer);
    void init_primary();
    void handle_peers();
-    void repeer_pgs(osd_num_t osd_num);
+    void repeer_pgs(osd_num_t osd_num, bool is_connected);
-    void start_pg_peering(pg_t & pg);
+    void start_pg_peering(int i);
    void submit_sync_and_list_subop(osd_num_t role_osd, pg_peering_state_t *ps);
    void submit_list_subop(osd_num_t role_osd, pg_peering_state_t *ps);
    void discard_list_subop(osd_op_t *list_op);
    bool stop_pg(pg_t & pg);
    void finish_stop_pg(pg_t & pg);
    // flushing, recovery and backfill
    void submit_pg_flush_ops(pg_t & pg);
    void handle_flush_op(bool rollback, pool_id_t pool_id, pg_num_t pg_num, pg_flush_batch_t *fb, osd_num_t peer_osd, int retval);
    void submit_flush_op(pool_id_t pool_id, pg_num_t pg_num, pg_flush_batch_t *fb, bool rollback, osd_num_t peer_osd, int count, obj_ver_id *data);
    bool pick_next_recovery(osd_recovery_op_t &op);
    void submit_recovery_op(osd_recovery_op_t *op);
    bool continue_recovery();
    pg_osd_set_state_t* change_osd_set(pg_osd_set_state_t *st, pg_t *pg);
    // op execution
    void exec_op(osd_op_t *cur_op);
    void finish_op(osd_op_t *cur_op, int retval);
    // secondary ops
    void exec_sync_stab_all(osd_op_t *cur_op);
@ -180,37 +246,18 @@ class osd_t
    void secondary_op_callback(osd_op_t *cur_op);
    // primary ops
    void autosync();
    bool prepare_primary_rw(osd_op_t *cur_op);
    void continue_primary_read(osd_op_t *cur_op);
    void continue_primary_write(osd_op_t *cur_op);
    void cancel_primary_write(osd_op_t *cur_op);
    void continue_primary_sync(osd_op_t *cur_op);
-    void continue_primary_del(osd_op_t *cur_op);
+    void finish_primary_op(osd_op_t *cur_op, int retval);
-    bool check_write_queue(osd_op_t *cur_op, pg_t & pg);
+    void handle_primary_subop(osd_op_t *cur_op, int ok, uint64_t version);
-    void remove_object_from_state(object_id & oid, pg_osd_set_state_t *object_state, pg_t &pg);
+    void submit_primary_subops(int submit_type, int read_pg_size, const uint64_t* osd_set, osd_op_t *cur_op);
    bool remember_unstable_write(osd_op_t *cur_op, pg_t & pg, pg_osd_set_t & loc_set, int base_state);
    void handle_primary_subop(osd_op_t *subop, osd_op_t *cur_op);
    void handle_primary_bs_subop(osd_op_t *subop);
    void add_bs_subop_stats(osd_op_t *subop);
    void pg_cancel_write_queue(pg_t & pg, osd_op_t *first_op, object_id oid, int retval);
    void submit_primary_subops(int submit_type, uint64_t op_version, int pg_size, const uint64_t* osd_set, osd_op_t *cur_op);
    void submit_primary_del_subops(osd_op_t *cur_op, uint64_t *cur_set, uint64_t set_size, pg_osd_set_t & loc_set);
    void submit_primary_sync_subops(osd_op_t *cur_op);
    void submit_primary_stab_subops(osd_op_t *cur_op);
    inline pg_num_t map_to_pg(object_id oid, uint64_t pg_stripe_size)
    {
        uint64_t pg_count = pg_counts[INODE_POOL(oid.inode)];
        if (!pg_count)
            pg_count = 1;
        return (oid.inode + oid.stripe / pg_stripe_size) % pg_count + 1;
    }
 public:
    osd_t(blockstore_config_t & config, blockstore_t *bs, ring_loop_t *ringloop);
    ~osd_t();
    void force_stop(int exitcode);
    bool shutdown();
 };
--- a/osd_client.cpp
+++ b/osd_client.cpp
@ -0,0 +1,40 @@
 void slice()
 {
    // Slice the request into blockstore requests to individual objects
    // Primary OSD still operates individual stripes, except they're twice the size of the blockstore's stripe.
    std::vector read_parts;
    int block = bs->get_block_size();
    uint64_t stripe1 = cur_op->req.rw.offset / block / 2;
    uint64_t stripe2 = (cur_op->req.rw.offset + cur_op->req.rw.len + block*2 - 1) / block / 2 - 1;
    for (uint64_t s = stripe1; s <= stripe2; s++)
    {
        uint64_t start = s == stripe1 ? cur_op->req.rw.offset - stripe1*block*2 : 0;
        uint64_t end = s == stripe2 ? cur_op->req.rw.offset + cur_op->req.rw.len - stripe2*block*2 : block*2;
        if (start < block)
        {
            read_parts.push_back({
                .role = 1,
                .oid = {
                    .inode = cur_op->req.rw.inode,
                    .stripe = (s << STRIPE_ROLE_BITS) | 1,
                },
                .version = UINT64_MAX,
                .offset = start,
                .len = (block < end ? block : end) - start,
            });
        }
        if (end > block)
        {
            read_parts.push_back({
                .role = 2,
                .oid = {
                    .inode = cur_op->req.rw.inode,
                    .stripe = (s << STRIPE_ROLE_BITS) | 2,
                },
                .version = UINT64_MAX,
                .offset = (start > block ? start-block : 0),
                .len = end - (start > block ? start-block : 0),
            });
        }
    }
 }
--- a/osd_cluster.cpp
+++ b/osd_cluster.cpp
@ -1,791 +0,0 @@
 // Copyright (c) Vitaliy Filippov, 2019+
 // License: VNPL-1.0 (see README.md for details)
 #include "osd.h"
 #include "base64.h"
 #include "etcd_state_client.h"
 // Startup sequence:
 //   Start etcd watcher -> Load global OSD configuration -> Bind socket -> Acquire lease -> Report&lock OSD state
 //   -> Load PG config -> Report&lock PG states -> Load peers -> Connect to peers -> Peer PGs
 // Event handling
 //   Wait for PG changes -> Start/Stop PGs when requested
 //   Peer connection is lost -> Reload connection data -> Try to reconnect
 void osd_t::init_cluster()
 {
    if (!st_cli.etcd_addresses.size())
    {
        if (run_primary)
        {
            // Test version of clustering code with 1 pool, 1 PG and 2 peers
            // Example: peers = 2:127.0.0.1:11204,3:127.0.0.1:11205
            std::string peerstr = config["peers"];
            while (peerstr.size())
            {
                int pos = peerstr.find(',');
                parse_test_peer(pos < 0 ? peerstr : peerstr.substr(0, pos));
                peerstr = pos < 0 ? std::string("") : peerstr.substr(pos+1);
            }
            if (st_cli.peer_states.size() < 2)
            {
                throw std::runtime_error("run_primary requires at least 2 peers");
            }
            pgs[{ 1, 1 }] = (pg_t){
                .state = PG_PEERING,
                .pg_cursize = 0,
                .pool_id = 1,
                .pg_num = 1,
                .target_set = { 1, 2, 3 },
                .cur_set = { 0, 0, 0 },
            };
            report_pg_state(pgs[{ 1, 1 }]);
            pg_counts[1] = 1;
        }
        bind_socket();
    }
    else
    {
        st_cli.tfd = tfd;
        st_cli.log_level = log_level;
        st_cli.on_change_osd_state_hook = [this](osd_num_t peer_osd) { on_change_osd_state_hook(peer_osd); };
        st_cli.on_change_pg_history_hook = [this](pool_id_t pool_id, pg_num_t pg_num) { on_change_pg_history_hook(pool_id, pg_num); };
        st_cli.on_change_hook = [this](json11::Json::object & changes) { on_change_etcd_state_hook(changes); };
        st_cli.on_load_config_hook = [this](json11::Json::object & cfg) { on_load_config_hook(cfg); };
        st_cli.load_pgs_checks_hook = [this]() { return on_load_pgs_checks_hook(); };
        st_cli.on_load_pgs_hook = [this](bool success) { on_load_pgs_hook(success); };
        peering_state = OSD_LOADING_PGS;
        st_cli.load_global_config();
    }
    if (run_primary && autosync_interval > 0)
    {
        this->tfd->set_timer(autosync_interval*1000, true, [this](int timer_id)
        {
            autosync();
        });
    }
 }
 void osd_t::parse_test_peer(std::string peer)
 {
    // OSD_NUM:IP:PORT
    int pos1 = peer.find(':');
    int pos2 = peer.find(':', pos1+1);
    if (pos1 < 0 || pos2 < 0)
        throw new std::runtime_error("OSD peer string must be in the form OSD_NUM:IP:PORT");
    std::string addr = peer.substr(pos1+1, pos2-pos1-1);
    std::string osd_num_str = peer.substr(0, pos1);
    std::string port_str = peer.substr(pos2+1);
    osd_num_t peer_osd = strtoull(osd_num_str.c_str(), NULL, 10);
    if (!peer_osd)
        throw new std::runtime_error("Could not parse OSD peer osd_num");
    else if (st_cli.peer_states.find(peer_osd) != st_cli.peer_states.end())
        throw std::runtime_error("Same osd number "+std::to_string(peer_osd)+" specified twice in peers");
    int port = strtoull(port_str.c_str(), NULL, 10);
    if (!port)
        throw new std::runtime_error("Could not parse OSD peer port");
    st_cli.peer_states[peer_osd] = json11::Json::object {
        { "state", "up" },
        { "addresses", json11::Json::array { addr } },
        { "port", port },
    };
    c_cli.connect_peer(peer_osd, st_cli.peer_states[peer_osd]);
 }
 json11::Json osd_t::get_osd_state()
 {
    std::vector<char> hostname;
    hostname.resize(1024);
    while (gethostname(hostname.data(), hostname.size()) < 0 && errno == ENAMETOOLONG)
        hostname.resize(hostname.size()+1024);
    hostname.resize(strnlen(hostname.data(), hostname.size()));
    json11::Json::object st;
    st["state"] = "up";
    if (bind_address != "0.0.0.0")
        st["addresses"] = json11::Json::array { bind_address };
    else
        st["addresses"] = getifaddr_list();
    st["host"] = std::string(hostname.data(), hostname.size());
    st["port"] = listening_port;
    st["primary_enabled"] = run_primary;
    st["blockstore_enabled"] = bs ? true : false;
    return st;
 }
 json11::Json osd_t::get_statistics()
 {
    json11::Json::object st;
    timespec ts;
    clock_gettime(CLOCK_REALTIME, &ts);
    char time_str[50] = { 0 };
    sprintf(time_str, "%ld.%03ld", ts.tv_sec, ts.tv_nsec/1000000);
    st["time"] = time_str;
    st["blockstore_ready"] = bs->is_started();
    if (bs)
    {
        st["size"] = bs->get_block_count() * bs->get_block_size();
        st["free"] = bs->get_free_block_count() * bs->get_block_size();
    }
    st["host"] = self_state["host"];
    json11::Json::object op_stats, subop_stats;
    for (int i = 0; i <= OSD_OP_MAX; i++)
    {
        op_stats[osd_op_names[i]] = json11::Json::object {
            { "count", c_cli.stats.op_stat_count[i] },
            { "usec", c_cli.stats.op_stat_sum[i] },
            { "bytes", c_cli.stats.op_stat_bytes[i] },
        };
    }
    for (int i = 0; i <= OSD_OP_MAX; i++)
    {
        subop_stats[osd_op_names[i]] = json11::Json::object {
            { "count", c_cli.stats.subop_stat_count[i] },
            { "usec", c_cli.stats.subop_stat_sum[i] },
        };
    }
    st["op_stats"] = op_stats;
    st["subop_stats"] = subop_stats;
    st["recovery_stats"] = json11::Json::object {
        { recovery_stat_names[0], json11::Json::object {
            { "count", recovery_stat_count[0][0] },
            { "bytes", recovery_stat_bytes[0][0] },
        } },
        { recovery_stat_names[1], json11::Json::object {
            { "count", recovery_stat_count[0][1] },
            { "bytes", recovery_stat_bytes[0][1] },
        } },
    };
    return st;
 }
 void osd_t::report_statistics()
 {
    if (etcd_reporting_stats)
    {
        return;
    }
    etcd_reporting_stats = true;
    json11::Json::array txn = { json11::Json::object {
        { "request_put", json11::Json::object {
            { "key", base64_encode(st_cli.etcd_prefix+"/osd/stats/"+std::to_string(osd_num)) },
            { "value", base64_encode(get_statistics().dump()) },
        } }
    } };
    for (auto & p: pgs)
    {
        auto & pg = p.second;
        if (pg.state & (PG_OFFLINE | PG_STARTING))
        {
            // Don't report statistics for offline PGs
            continue;
        }
        json11::Json::object pg_stats;
        pg_stats["object_count"] = pg.total_count;
        pg_stats["clean_count"] = pg.clean_count;
        pg_stats["misplaced_count"] = pg.misplaced_objects.size();
        pg_stats["degraded_count"] = pg.degraded_objects.size();
        pg_stats["incomplete_count"] = pg.incomplete_objects.size();
        pg_stats["write_osd_set"] = pg.cur_set;
        txn.push_back(json11::Json::object {
            { "request_put", json11::Json::object {
                { "key", base64_encode(st_cli.etcd_prefix+"/pg/stats/"+std::to_string(pg.pool_id)+"/"+std::to_string(pg.pg_num)) },
                { "value", base64_encode(json11::Json(pg_stats).dump()) },
            } }
        });
    }
    st_cli.etcd_txn(json11::Json::object { { "success", txn } }, ETCD_SLOW_TIMEOUT, [this](std::string err, json11::Json res)
    {
        etcd_reporting_stats = false;
        if (err != "")
        {
            printf("[OSD %lu] Error reporting state to etcd: %s\n", this->osd_num, err.c_str());
            // Retry indefinitely
            tfd->set_timer(ETCD_SLOW_TIMEOUT, false, [this](int timer_id)
            {
                report_statistics();
            });
        }
        else if (res["error"].string_value() != "")
        {
            printf("[OSD %lu] Error reporting state to etcd: %s\n", this->osd_num, res["error"].string_value().c_str());
            force_stop(1);
        }
    });
 }
 void osd_t::on_change_osd_state_hook(osd_num_t peer_osd)
 {
    if (c_cli.wanted_peers.find(peer_osd) != c_cli.wanted_peers.end())
    {
        c_cli.connect_peer(peer_osd, st_cli.peer_states[peer_osd]);
    }
 }
 void osd_t::on_change_etcd_state_hook(json11::Json::object & changes)
 {
    // FIXME apply config changes in runtime (maybe, some)
    apply_pg_count();
    apply_pg_config();
 }
 void osd_t::on_change_pg_history_hook(pool_id_t pool_id, pg_num_t pg_num)
 {
    auto pg_it = pgs.find({
        .pool_id = pool_id,
        .pg_num = pg_num,
    });
    if (pg_it != pgs.end() && pg_it->second.epoch > pg_it->second.reported_epoch &&
        st_cli.pool_config[pool_id].pg_config[pg_num].epoch >= pg_it->second.epoch)
    {
        pg_it->second.reported_epoch = st_cli.pool_config[pool_id].pg_config[pg_num].epoch;
        object_id oid = { 0 };
        bool first = true;
        for (auto op: pg_it->second.write_queue)
        {
            if (first || oid != op.first)
            {
                oid = op.first;
                first = false;
                continue_primary_write(op.second);
            }
        }
    }
 }
 void osd_t::on_load_config_hook(json11::Json::object & global_config)
 {
    blockstore_config_t osd_config = this->config;
    for (auto & cfg_var: global_config)
    {
        if (this->config.find(cfg_var.first) == this->config.end())
        {
            if (cfg_var.second.is_string())
            {
                osd_config[cfg_var.first] = cfg_var.second.string_value();
            }
            else
            {
                osd_config[cfg_var.first] = cfg_var.second.dump();
            }
        }
    }
    parse_config(osd_config);
    bind_socket();
    st_cli.start_etcd_watcher();
    acquire_lease();
 }
 // Acquire lease
 void osd_t::acquire_lease()
 {
    // Maximum lease TTL is (report interval) + retries * (timeout + repeat interval)
    st_cli.etcd_call("/lease/grant", json11::Json::object {
        { "TTL", etcd_report_interval+(MAX_ETCD_ATTEMPTS*(2*ETCD_QUICK_TIMEOUT)+999)/1000 }
    }, ETCD_QUICK_TIMEOUT, [this](std::string err, json11::Json data)
    {
        if (err != "" || data["ID"].string_value() == "")
        {
            printf("Error acquiring a lease from etcd: %s\n", err.c_str());
            tfd->set_timer(ETCD_QUICK_TIMEOUT, false, [this](int timer_id)
            {
                acquire_lease();
            });
            return;
        }
        etcd_lease_id = data["ID"].string_value();
        create_osd_state();
    });
    printf("[OSD %lu] reporting to etcd at %s every %d seconds\n", this->osd_num, config["etcd_address"].c_str(), etcd_report_interval);
    tfd->set_timer(etcd_report_interval*1000, true, [this](int timer_id)
    {
        renew_lease();
    });
 }
 // Report "up" state once, then keep it alive using the lease
 // Do it first to allow "monitors" check it when moving PGs
 void osd_t::create_osd_state()
 {
    std::string state_key = base64_encode(st_cli.etcd_prefix+"/osd/state/"+std::to_string(osd_num));
    self_state = get_osd_state();
    st_cli.etcd_txn(json11::Json::object {
        // Check that the state key does not exist
        { "compare", json11::Json::array {
            json11::Json::object {
                { "target", "CREATE" },
                { "create_revision", 0 },
                { "key", state_key },
            }
        } },
        { "success", json11::Json::array {
            json11::Json::object {
                { "request_put", json11::Json::object {
                    { "key", state_key },
                    { "value", base64_encode(self_state.dump()) },
                    { "lease", etcd_lease_id },
                } }
            },
        } },
        { "failure", json11::Json::array {
            json11::Json::object {
                { "request_range", json11::Json::object {
                    { "key", state_key },
                } }
            },
        } },
    }, ETCD_QUICK_TIMEOUT, [this](std::string err, json11::Json data)
    {
        if (err != "")
        {
            etcd_failed_attempts++;
            printf("Error creating OSD state key: %s\n", err.c_str());
            if (etcd_failed_attempts > MAX_ETCD_ATTEMPTS)
            {
                // Die
                throw std::runtime_error("Cluster connection failed");
            }
            // Retry
            tfd->set_timer(ETCD_QUICK_TIMEOUT, false, [this](int timer_id)
            {
                create_osd_state();
            });
            return;
        }
        if (!data["succeeded"].bool_value())
        {
            // OSD is already up
            auto kv = st_cli.parse_etcd_kv(data["responses"][0]["response_range"]["kvs"][0]);
            printf("Key %s already exists in etcd, OSD %lu is still up\n", kv.key.c_str(), this->osd_num);
            int64_t port = kv.value["port"].int64_value();
            for (auto & addr: kv.value["addresses"].array_items())
            {
                printf("  listening at: %s:%ld\n", addr.string_value().c_str(), port);
            }
            force_stop(0);
            return;
        }
        if (run_primary)
        {
            st_cli.load_pgs();
        }
    });
 }
 // Renew lease
 void osd_t::renew_lease()
 {
    st_cli.etcd_call("/lease/keepalive", json11::Json::object {
        { "ID", etcd_lease_id }
    }, ETCD_QUICK_TIMEOUT, [this](std::string err, json11::Json data)
    {
        if (err == "" && data["result"]["TTL"].string_value() == "")
        {
            // Die
            throw std::runtime_error("etcd lease has expired");
        }
        if (err != "")
        {
            etcd_failed_attempts++;
            printf("Error renewing etcd lease: %s\n", err.c_str());
            if (etcd_failed_attempts > MAX_ETCD_ATTEMPTS)
            {
                // Die
                throw std::runtime_error("Cluster connection failed");
            }
            // Retry
            tfd->set_timer(ETCD_QUICK_TIMEOUT, false, [this](int timer_id)
            {
                renew_lease();
            });
        }
        else
        {
            etcd_failed_attempts = 0;
            report_statistics();
        }
    });
 }
 void osd_t::force_stop(int exitcode)
 {
    if (etcd_lease_id != "")
    {
        st_cli.etcd_call("/kv/lease/revoke", json11::Json::object {
            { "ID", etcd_lease_id }
        }, ETCD_QUICK_TIMEOUT, [this, exitcode](std::string err, json11::Json data)
        {
            if (err != "")
            {
                printf("Error revoking etcd lease: %s\n", err.c_str());
            }
            printf("[OSD %lu] Force stopping\n", this->osd_num);
            exit(exitcode);
        });
    }
    else
    {
        printf("[OSD %lu] Force stopping\n", this->osd_num);
        exit(exitcode);
    }
 }
 json11::Json osd_t::on_load_pgs_checks_hook()
 {
    assert(this->pgs.size() == 0);
    json11::Json::array checks = {
        json11::Json::object {
            { "target", "LEASE" },
            { "lease", etcd_lease_id },
            { "key", base64_encode(st_cli.etcd_prefix+"/osd/state/"+std::to_string(osd_num)) },
        }
    };
    return checks;
 }
 void osd_t::on_load_pgs_hook(bool success)
 {
    if (!success)
    {
        printf("Error loading PGs from etcd: lease expired\n");
        force_stop(1);
    }
    else
    {
        peering_state &= ~OSD_LOADING_PGS;
        apply_pg_count();
        apply_pg_config();
    }
 }
 void osd_t::apply_pg_count()
 {
    for (auto & pool_item: st_cli.pool_config)
    {
        if (pool_item.second.real_pg_count != 0 &&
            pool_item.second.real_pg_count != pg_counts[pool_item.first])
        {
            // Check that all pool PGs are offline. It is not allowed to change PG count when any PGs are online
            // The external tool must wait for all PGs to come down before changing PG count
            // If it doesn't wait, a restarted OSD may apply the new count immediately which will lead to bugs
            // So an OSD just dies if it detects PG count change while there are active PGs
            int still_active = 0;
            for (auto & kv: pgs)
            {
                if (kv.first.pool_id == pool_item.first && (kv.second.state & PG_ACTIVE))
                {
                    still_active++;
                }
            }
            if (still_active > 0)
            {
                printf("[OSD %lu] PG count change detected, but %d PG(s) are still active. This is not allowed. Exiting\n", this->osd_num, still_active);
                force_stop(1);
                return;
            }
        }
        this->pg_counts[pool_item.first] = pool_item.second.real_pg_count;
    }
 }
 void osd_t::apply_pg_config()
 {
    bool all_applied = true;
    for (auto & pool_item: st_cli.pool_config)
    {
        auto pool_id = pool_item.first;
        for (auto & kv: pool_item.second.pg_config)
        {
            pg_num_t pg_num = kv.first;
            auto & pg_cfg = kv.second;
            bool take = pg_cfg.exists && pg_cfg.primary == this->osd_num &&
                !pg_cfg.pause && (!pg_cfg.cur_primary || pg_cfg.cur_primary == this->osd_num);
            auto pg_it = this->pgs.find({ .pool_id = pool_id, .pg_num = pg_num });
            bool currently_taken = pg_it != this->pgs.end() && pg_it->second.state != PG_OFFLINE;
            if (currently_taken && !take)
            {
                // Stop this PG
                stop_pg(pg_it->second);
            }
            else if (take)
            {
                // Take this PG
                std::set<osd_num_t> all_peers;
                for (osd_num_t pg_osd: pg_cfg.target_set)
                {
                    if (pg_osd != 0)
                    {
                        all_peers.insert(pg_osd);
                    }
                }
                for (osd_num_t pg_osd: pg_cfg.all_peers)
                {
                    if (pg_osd != 0)
                    {
                        all_peers.insert(pg_osd);
                    }
                }
                for (auto & hist_item: pg_cfg.target_history)
                {
                    for (auto pg_osd: hist_item)
                    {
                        if (pg_osd != 0)
                        {
                            all_peers.insert(pg_osd);
                        }
                    }
                }
                if (currently_taken)
                {
                    if (pg_it->second.state & (PG_ACTIVE | PG_INCOMPLETE | PG_PEERING))
                    {
                        if (pg_it->second.target_set == pg_cfg.target_set)
                        {
                            // No change in osd_set; history changes are ignored
                            continue;
                        }
                        else
                        {
                            // Stop PG, reapply change after stopping
                            stop_pg(pg_it->second);
                            all_applied = false;
                            continue;
                        }
                    }
                    else if (pg_it->second.state & PG_STOPPING)
                    {
                        // Reapply change after stopping
                        all_applied = false;
                        continue;
                    }
                    else if (pg_it->second.state & PG_STARTING)
                    {
                        if (pg_cfg.cur_primary == this->osd_num)
                        {
                            // PG locked, continue
                        }
                        else
                        {
                            // Reapply change after locking the PG
                            all_applied = false;
                            continue;
                        }
                    }
                    else
                    {
                        throw std::runtime_error("Unexpected PG "+std::to_string(pg_num)+" state: "+std::to_string(pg_it->second.state));
                    }
                }
                auto & pg = this->pgs[{ .pool_id = pool_id, .pg_num = pg_num }];
                pg = (pg_t){
                    .state = pg_cfg.cur_primary == this->osd_num ? PG_PEERING : PG_STARTING,
                    .scheme = pool_item.second.scheme,
                    .pg_cursize = 0,
                    .pg_size = pool_item.second.pg_size,
                    .pg_minsize = pool_item.second.pg_minsize,
                    .pool_id = pool_id,
                    .pg_num = pg_num,
                    .reported_epoch = pg_cfg.epoch,
                    .target_history = pg_cfg.target_history,
                    .all_peers = std::vector<osd_num_t>(all_peers.begin(), all_peers.end()),
                    .target_set = pg_cfg.target_set,
                };
                this->pg_state_dirty.insert({ .pool_id = pool_id, .pg_num = pg_num });
                pg.print_state();
                if (pg_cfg.cur_primary == this->osd_num)
                {
                    // Add peers
                    for (auto pg_osd: all_peers)
                    {
                        if (pg_osd != this->osd_num && c_cli.osd_peer_fds.find(pg_osd) == c_cli.osd_peer_fds.end())
                        {
                            c_cli.connect_peer(pg_osd, st_cli.peer_states[pg_osd]);
                        }
                    }
                    start_pg_peering(pg);
                }
                else
                {
                    // Reapply change after locking the PG
                    all_applied = false;
                }
            }
        }
    }
    report_pg_states();
    this->pg_config_applied = all_applied;
 }
 void osd_t::report_pg_states()
 {
    if (etcd_reporting_pg_state || !this->pg_state_dirty.size() || !st_cli.etcd_addresses.size())
    {
        return;
    }
    std::vector<std::pair<pool_pg_num_t,bool>> reporting_pgs;
    json11::Json::array checks;
    json11::Json::array success;
    json11::Json::array failure;
    for (auto it = pg_state_dirty.begin(); it != pg_state_dirty.end(); it++)
    {
        auto pg_it = this->pgs.find(*it);
        if (pg_it == this->pgs.end())
        {
            continue;
        }
        auto & pg = pg_it->second;
        reporting_pgs.push_back({ *it, pg.history_changed });
        std::string state_key_base64 = base64_encode(st_cli.etcd_prefix+"/pg/state/"+std::to_string(pg.pool_id)+"/"+std::to_string(pg.pg_num));
        if (pg.state == PG_STARTING)
        {
            // Check that the PG key does not exist
            // Failed check indicates an unsuccessful PG lock attempt in this case
            checks.push_back(json11::Json::object {
                { "target", "VERSION" },
                { "version", 0 },
                { "key", state_key_base64 },
            });
        }
        else
        {
            // Check that the key is ours
            // Failed check indicates success for OFFLINE pgs (PG lock is already deleted)
            // and an unexpected race condition for started pgs (PG lock is held by someone else)
            checks.push_back(json11::Json::object {
                { "target", "LEASE" },
                { "lease", etcd_lease_id },
                { "key", state_key_base64 },
            });
        }
        if (pg.state == PG_OFFLINE)
        {
            success.push_back(json11::Json::object {
                { "request_delete_range", json11::Json::object {
                    { "key", state_key_base64 },
                } }
            });
        }
        else
        {
            json11::Json::array pg_state_keywords;
            for (int i = 0; i < pg_state_bit_count; i++)
            {
                if (pg.state & pg_state_bits[i])
                {
                    pg_state_keywords.push_back(pg_state_names[i]);
                }
            }
            success.push_back(json11::Json::object {
                { "request_put", json11::Json::object {
                    { "key", state_key_base64 },
                    { "value", base64_encode(json11::Json(json11::Json::object {
                        { "primary", this->osd_num },
                        { "state", pg_state_keywords },
                        { "peers", pg.cur_peers },
                    }).dump()) },
                    { "lease", etcd_lease_id },
                } }
            });
            if (pg.history_changed)
            {
                // Prevent race conditions (for the case when the monitor is updating this key at the same time)
                pg.history_changed = false;
                std::string history_key = base64_encode(st_cli.etcd_prefix+"/pg/history/"+std::to_string(pg.pool_id)+"/"+std::to_string(pg.pg_num));
                json11::Json::object history_value = {
                    { "epoch", pg.epoch },
                    { "all_peers", pg.all_peers },
                    { "osd_sets", pg.target_history },
                };
                checks.push_back(json11::Json::object {
                    { "target", "MOD" },
                    { "key", history_key },
                    { "result", "LESS" },
                    { "mod_revision", st_cli.etcd_watch_revision+1 },
                });
                success.push_back(json11::Json::object {
                    { "request_put", json11::Json::object {
                        { "key", history_key },
                        { "value", base64_encode(json11::Json(history_value).dump()) },
                    } }
                });
            }
        }
        failure.push_back(json11::Json::object {
            { "request_range", json11::Json::object {
                { "key", state_key_base64 },
            } }
        });
    }
    pg_state_dirty.clear();
    etcd_reporting_pg_state = true;
    st_cli.etcd_txn(json11::Json::object {
        { "compare", checks }, { "success", success }, { "failure", failure }
    }, ETCD_QUICK_TIMEOUT, [this, reporting_pgs](std::string err, json11::Json data)
    {
        etcd_reporting_pg_state = false;
        if (!data["succeeded"].bool_value())
        {
            // One of PG state updates failed, put dirty flags back
            for (auto pp: reporting_pgs)
            {
                this->pg_state_dirty.insert(pp.first);
                if (pp.second)
                {
                    auto pg_it = this->pgs.find(pp.first);
                    if (pg_it != this->pgs.end())
                    {
                        pg_it->second.history_changed = true;
                    }
                }
            }
            for (auto & res: data["responses"].array_items())
            {
                if (res["kvs"].array_items().size())
                {
                    auto kv = st_cli.parse_etcd_kv(res["kvs"][0]);
                    if (kv.key.substr(st_cli.etcd_prefix.length()+10) == st_cli.etcd_prefix+"/pg/state/")
                    {
                        pool_id_t pool_id = 0;
                        pg_num_t pg_num = 0;
                        char null_byte = 0;
                        sscanf(kv.key.c_str() + st_cli.etcd_prefix.length()+10, "%u/%u%c", &pool_id, &pg_num, &null_byte);
                        if (null_byte == 0)
                        {
                            auto pg_it = pgs.find({ .pool_id = pool_id, .pg_num = pg_num });
                            if (pg_it != pgs.end() && pg_it->second.state != PG_OFFLINE && pg_it->second.state != PG_STARTING)
                            {
                                // Live PG state update failed
                                printf("Failed to report state of pool %u PG %u which is live. Race condition detected, exiting\n", pool_id, pg_num);
                                force_stop(1);
                                return;
                            }
                        }
                    }
                }
            }
            // Retry after a short pause (hope we'll get some updates and update PG states accordingly)
            tfd->set_timer(500, false, [this](int) { report_pg_states(); });
        }
        else
        {
            // Success. We'll get our changes back via the watcher and react to them
            for (auto pp: reporting_pgs)
            {
                auto pg_it = this->pgs.find(pp.first);
                if (pg_it != this->pgs.end())
                {
                    if (pg_it->second.state == PG_OFFLINE)
                    {
                        // Remove offline PGs after reporting their state
                        this->pgs.erase(pg_it);
                    }
                }
            }
            // Push other PG state updates, if any
            report_pg_states();
            if (!this->pg_state_dirty.size())
            {
                // Update statistics
                report_statistics();
            }
        }
    });
 }
--- a/osd_flush.cpp
+++ b/osd_flush.cpp
@ -1,300 +0,0 @@
 // Copyright (c) Vitaliy Filippov, 2019+
 // License: VNPL-1.0 (see README.md for details)
 #include "osd.h"
 #define FLUSH_BATCH 512
 void osd_t::submit_pg_flush_ops(pg_t & pg)
 {
    pg_flush_batch_t *fb = new pg_flush_batch_t();
    pg.flush_batch = fb;
    auto it = pg.flush_actions.begin(), prev_it = pg.flush_actions.begin();
    bool first = true;
    while (it != pg.flush_actions.end())
    {
        if (!first && (it->first.oid.inode != prev_it->first.oid.inode ||
            (it->first.oid.stripe & ~STRIPE_MASK) != (prev_it->first.oid.stripe & ~STRIPE_MASK)) &&
            fb->rollback_lists[it->first.osd_num].size() >= FLUSH_BATCH ||
            fb->stable_lists[it->first.osd_num].size() >= FLUSH_BATCH)
        {
            // Stop only at the object boundary
            break;
        }
        it->second.submitted = true;
        if (it->second.rollback)
        {
            fb->flush_objects++;
            fb->rollback_lists[it->first.osd_num].push_back((obj_ver_id){
                .oid = it->first.oid,
                .version = it->second.rollback_to,
            });
        }
        if (it->second.make_stable)
        {
            fb->flush_objects++;
            fb->stable_lists[it->first.osd_num].push_back((obj_ver_id){
                .oid = it->first.oid,
                .version = it->second.stable_to,
            });
        }
        prev_it = it;
        first = false;
        it++;
    }
    for (auto & l: fb->rollback_lists)
    {
        if (l.second.size() > 0)
        {
            fb->flush_ops++;
            submit_flush_op(pg.pool_id, pg.pg_num, fb, true, l.first, l.second.size(), l.second.data());
        }
    }
    for (auto & l: fb->stable_lists)
    {
        if (l.second.size() > 0)
        {
            fb->flush_ops++;
            submit_flush_op(pg.pool_id, pg.pg_num, fb, false, l.first, l.second.size(), l.second.data());
        }
    }
 }
 void osd_t::handle_flush_op(bool rollback, pool_id_t pool_id, pg_num_t pg_num, pg_flush_batch_t *fb, osd_num_t peer_osd, int retval)
 {
    pool_pg_num_t pg_id = { .pool_id = pool_id, .pg_num = pg_num };
    if (pgs.find(pg_id) == pgs.end() || pgs[pg_id].flush_batch != fb)
    {
        // Throw the result away
        return;
    }
    if (retval != 0)
    {
        if (peer_osd == this->osd_num)
        {
            throw std::runtime_error(
                std::string(rollback
                    ? "Error while doing local rollback operation: "
                    : "Error while doing local stabilize operation: "
                ) + strerror(-retval)
            );
        }
        else
        {
            printf("Error while doing flush on OSD %lu: %d (%s)\n", osd_num, retval, strerror(-retval));
            auto fd_it = c_cli.osd_peer_fds.find(peer_osd);
            if (fd_it != c_cli.osd_peer_fds.end())
            {
                c_cli.stop_client(fd_it->second);
            }
            return;
        }
    }
    fb->flush_done++;
    if (fb->flush_done == fb->flush_ops)
    {
        // This flush batch is done
        std::vector<osd_op_t*> continue_ops;
        auto & pg = pgs[pg_id];
        auto it = pg.flush_actions.begin(), prev_it = it;
        auto erase_start = it;
        while (1)
        {
            if (it == pg.flush_actions.end() ||
                it->first.oid.inode != prev_it->first.oid.inode ||
                (it->first.oid.stripe & ~STRIPE_MASK) != (prev_it->first.oid.stripe & ~STRIPE_MASK))
            {
                pg.ver_override.erase((object_id){
                    .inode = prev_it->first.oid.inode,
                    .stripe = (prev_it->first.oid.stripe & ~STRIPE_MASK),
                });
                auto wr_it = pg.write_queue.find((object_id){
                    .inode = prev_it->first.oid.inode,
                    .stripe = (prev_it->first.oid.stripe & ~STRIPE_MASK),
                });
                if (wr_it != pg.write_queue.end())
                {
                    continue_ops.push_back(wr_it->second);
                    pg.write_queue.erase(wr_it);
                }
            }
            if ((it == pg.flush_actions.end() || !it->second.submitted) &&
                erase_start != it)
            {
                pg.flush_actions.erase(erase_start, it);
            }
            if (it == pg.flush_actions.end())
            {
                break;
            }
            prev_it = it;
            if (!it->second.submitted)
            {
                it++;
                erase_start = it;
            }
            else
            {
                it++;
            }
        }
        delete fb;
        pg.flush_batch = NULL;
        if (!pg.flush_actions.size())
        {
            pg.state = pg.state & ~PG_HAS_UNCLEAN;
            report_pg_state(pg);
        }
        for (osd_op_t *op: continue_ops)
        {
            continue_primary_write(op);
        }
        if (pg.inflight == 0 && (pg.state & PG_STOPPING))
        {
            finish_stop_pg(pg);
        }
    }
 }
 void osd_t::submit_flush_op(pool_id_t pool_id, pg_num_t pg_num, pg_flush_batch_t *fb, bool rollback, osd_num_t peer_osd, int count, obj_ver_id *data)
 {
    osd_op_t *op = new osd_op_t();
    // Copy buffer so it gets freed along with the operation
    op->buf = malloc_or_die(sizeof(obj_ver_id) * count);
    memcpy(op->buf, data, sizeof(obj_ver_id) * count);
    if (peer_osd == this->osd_num)
    {
        // local
        clock_gettime(CLOCK_REALTIME, &op->tv_begin);
        op->bs_op = new blockstore_op_t({
            .opcode = (uint64_t)(rollback ? BS_OP_ROLLBACK : BS_OP_STABLE),
            .callback = [this, op, pool_id, pg_num, fb](blockstore_op_t *bs_op)
            {
                add_bs_subop_stats(op);
                handle_flush_op(bs_op->opcode == BS_OP_ROLLBACK, pool_id, pg_num, fb, this->osd_num, bs_op->retval);
                delete op->bs_op;
                op->bs_op = NULL;
                delete op;
            },
            .len = (uint32_t)count,
            .buf = op->buf,
        });
        bs->enqueue_op(op->bs_op);
    }
    else
    {
        // Peer
        int peer_fd = c_cli.osd_peer_fds[peer_osd];
        op->op_type = OSD_OP_OUT;
        op->iov.push_back(op->buf, count * sizeof(obj_ver_id));
        op->peer_fd = peer_fd;
        op->req = {
            .sec_stab = {
                .header = {
                    .magic = SECONDARY_OSD_OP_MAGIC,
                    .id = c_cli.next_subop_id++,
                    .opcode = (uint64_t)(rollback ? OSD_OP_SEC_ROLLBACK : OSD_OP_SEC_STABILIZE),
                },
                .len = count * sizeof(obj_ver_id),
            },
        };
        op->callback = [this, pool_id, pg_num, fb, peer_osd](osd_op_t *op)
        {
            handle_flush_op(op->req.hdr.opcode == OSD_OP_SEC_ROLLBACK, pool_id, pg_num, fb, peer_osd, op->reply.hdr.retval);
            delete op;
        };
        c_cli.outbox_push(op);
    }
 }
 bool osd_t::pick_next_recovery(osd_recovery_op_t &op)
 {
    for (auto pg_it = pgs.begin(); pg_it != pgs.end(); pg_it++)
    {
        if ((pg_it->second.state & (PG_ACTIVE | PG_HAS_DEGRADED)) == (PG_ACTIVE | PG_HAS_DEGRADED))
        {
            for (auto obj_it = pg_it->second.degraded_objects.begin(); obj_it != pg_it->second.degraded_objects.end(); obj_it++)
            {
                if (recovery_ops.find(obj_it->first) == recovery_ops.end())
                {
                    op.degraded = true;
                    op.oid = obj_it->first;
                    return true;
                }
            }
        }
    }
    for (auto pg_it = pgs.begin(); pg_it != pgs.end(); pg_it++)
    {
        if ((pg_it->second.state & (PG_ACTIVE | PG_HAS_MISPLACED)) == (PG_ACTIVE | PG_HAS_MISPLACED))
        {
            for (auto obj_it = pg_it->second.misplaced_objects.begin(); obj_it != pg_it->second.misplaced_objects.end(); obj_it++)
            {
                if (recovery_ops.find(obj_it->first) == recovery_ops.end())
                {
                    op.degraded = false;
                    op.oid = obj_it->first;
                    return true;
                }
            }
        }
    }
    return false;
 }
 void osd_t::submit_recovery_op(osd_recovery_op_t *op)
 {
    op->osd_op = new osd_op_t();
    op->osd_op->op_type = OSD_OP_OUT;
    op->osd_op->req = {
        .rw = {
            .header = {
                .magic = SECONDARY_OSD_OP_MAGIC,
                .id = 1,
                .opcode = OSD_OP_WRITE,
            },
            .inode = op->oid.inode,
            .offset = op->oid.stripe,
            .len = 0,
        },
    };
    op->osd_op->callback = [this, op](osd_op_t *osd_op)
    {
        // Don't sync the write, it will be synced by our regular sync coroutine
        if (osd_op->reply.hdr.retval < 0)
        {
            // Error recovering object
            if (osd_op->reply.hdr.retval == -EPIPE)
            {
                // PG is stopped or one of the OSDs is gone, error is harmless
            }
            else
            {
                throw std::runtime_error("Failed to recover an object");
            }
        }
        // CAREFUL! op = &recovery_ops[op->oid]. Don't access op->* after recovery_ops.erase()
        op->osd_op = NULL;
        recovery_ops.erase(op->oid);
        delete osd_op;
        continue_recovery();
    };
    exec_op(op->osd_op);
 }
 // Just trigger write requests for degraded objects. They'll be recovered during writing
 bool osd_t::continue_recovery()
 {
    while (recovery_ops.size() < recovery_queue_depth)
    {
        osd_recovery_op_t op;
        if (pick_next_recovery(op))
        {
            recovery_ops[op.oid] = op;
            submit_recovery_op(&recovery_ops[op.oid]);
        }
        else
            return false;
    }
    return true;
 }
--- a/osd_id.h
+++ b/osd_id.h
@ -1,27 +1,4 @@
 // Copyright (c) Vitaliy Filippov, 2019+
 // License: VNPL-1.0 or GNU GPL-2.0+ (see README.md for details)
 #pragma once
 #define POOL_SCHEME_REPLICATED 1
 #define POOL_SCHEME_XOR 2
 #define POOL_ID_MAX 0x10000
 #define POOL_ID_BITS 16
 #define INODE_POOL(inode) (pool_id_t)((inode) >> (64 - POOL_ID_BITS))
 // Pool ID is 16 bits long
 typedef uint32_t pool_id_t;
 typedef uint64_t osd_num_t;
 typedef uint32_t pg_num_t;
 struct pool_pg_num_t
 {
    pool_id_t pool_id;
    pg_num_t pg_num;
 };
 inline bool operator < (const pool_pg_num_t & a, const pool_pg_num_t & b)
 {
    return a.pool_id < b.pool_id || a.pool_id == b.pool_id && a.pg_num < b.pg_num;
 }
--- a/osd_main.cpp
+++ b/osd_main.cpp
@ -1,28 +1,14 @@
 // Copyright (c) Vitaliy Filippov, 2019+
 // License: VNPL-1.0 (see README.md for details)
 #include "osd.h"
 #include <signal.h>
-static osd_t *osd = NULL;
+void handle_sigint(int sig)
 static bool force_stopping = false;
 static void handle_sigint(int sig)
 {
    if (osd && !force_stopping)
    {
        force_stopping = true;
        osd->force_stop(0);
        return;
    }
    exit(0);
 }
 int main(int narg, char *args[])
 {
    setvbuf(stdout, NULL, _IONBF, 0);
    setvbuf(stderr, NULL, _IONBF, 0);
    if (sizeof(osd_any_op_t) > OSD_PACKET_SIZE ||
        sizeof(osd_any_reply_t) > OSD_PACKET_SIZE)
    {
@ -39,11 +25,9 @@ int main(int narg, char *args[])
        }
    }
    signal(SIGINT, handle_sigint);
    signal(SIGTERM, handle_sigint);
    ring_loop_t *ringloop = new ring_loop_t(512);
    // FIXME: Create Blockstore from on-disk superblock config and check it against the OSD cluster config
    blockstore_t *bs = new blockstore_t(config, ringloop);
-    osd = new osd_t(config, bs, ringloop);
+    osd_t *osd = new osd_t(config, bs, ringloop);
    while (1)
    {
        ringloop->loop();
--- a/osd_ops.cpp
+++ b/osd_ops.cpp
@ -1,22 +0,0 @@
 // Copyright (c) Vitaliy Filippov, 2019+
 // License: VNPL-1.0 or GNU GPL-2.0+ (see README.md for details)
 #include "osd_ops.h"
 const char* osd_op_names[] = {
    "",
    "read",
    "write",
    "write_stable",
    "sync",
    "stabilize",
    "rollback",
    "delete",
    "sync_stab_all",
    "list",
    "show_config",
    "primary_read",
    "primary_write",
    "primary_sync",
    "primary_delete",
 };
--- a/osd_ops.h
+++ b/osd_ops.h
@ -1,6 +1,3 @@
 // Copyright (c) Vitaliy Filippov, 2019+
 // License: VNPL-1.0 or GNU GPL-2.0+ (see README.md for details)
 #pragma once
 #include "object_id.h"
@ -13,25 +10,21 @@
 #define OSD_PACKET_SIZE             0x80
 // Opcodes
 #define OSD_OP_MIN                  1
-#define OSD_OP_SEC_READ             1
+#define OSD_OP_SECONDARY_READ       1
-#define OSD_OP_SEC_WRITE            2
+#define OSD_OP_SECONDARY_WRITE      2
-#define OSD_OP_SEC_WRITE_STABLE     3
+#define OSD_OP_SECONDARY_SYNC       3
-#define OSD_OP_SEC_SYNC             4
+#define OSD_OP_SECONDARY_STABILIZE  4
-#define OSD_OP_SEC_STABILIZE        5
+#define OSD_OP_SECONDARY_ROLLBACK   5
-#define OSD_OP_SEC_ROLLBACK         6
+#define OSD_OP_SECONDARY_DELETE     6
-#define OSD_OP_SEC_DELETE           7
+#define OSD_OP_TEST_SYNC_STAB_ALL   7
-#define OSD_OP_TEST_SYNC_STAB_ALL   8
+#define OSD_OP_SECONDARY_LIST       8
-#define OSD_OP_SEC_LIST             9
+#define OSD_OP_SHOW_CONFIG          9
-#define OSD_OP_SHOW_CONFIG          10
+#define OSD_OP_READ                 10
-#define OSD_OP_READ                 11
+#define OSD_OP_WRITE                11
-#define OSD_OP_WRITE                12
+#define OSD_OP_SYNC                 12
-#define OSD_OP_SYNC                 13
+#define OSD_OP_MAX                  12
 #define OSD_OP_DELETE               14
 #define OSD_OP_MAX                  14
 // Alignment & limit for read/write operations
-#ifndef MEM_ALIGNMENT
+#define OSD_RW_ALIGN                512
 #define MEM_ALIGNMENT               512
 #endif
 #define OSD_RW_MAX                  64*1024*1024
 // common request and reply headers
@ -64,7 +57,6 @@ struct __attribute__((__packed__)) osd_op_secondary_rw_t
    // object
    object_id oid;
    // read/write version (automatic or specific)
    // FIXME deny values close to UINT64_MAX
    uint64_t version;
    // offset
    uint32_t offset;
@ -138,10 +130,7 @@ struct __attribute__((__packed__)) osd_op_secondary_list_t
    osd_op_header_t header;
    // placement group total number and total count
    pg_num_t list_pg, pg_count;
-    // size of an area that maps to one PG continuously
+    uint64_t parity_block_size;
    uint64_t pg_stripe_size;
    // inode range (used to select pools)
    uint64_t min_inode, max_inode;
 };
 struct __attribute__((__packed__)) osd_reply_secondary_list_t
@ -153,7 +142,6 @@ struct __attribute__((__packed__)) osd_reply_secondary_list_t
 };
 // read or write to the primary OSD (must be within individual stripe)
 // FIXME: allow to return used block bitmap (required for snapshots)
 struct __attribute__((__packed__)) osd_op_rw_t
 {
    osd_op_header_t header;
@ -181,7 +169,6 @@ struct __attribute__((__packed__)) osd_reply_sync_t
    osd_reply_header_t header;
 };
 // FIXME it would be interesting to try to unify blockstore_op and osd_op formats
 union osd_any_op_t
 {
    osd_op_header_t hdr;
@ -209,5 +196,3 @@ union osd_any_reply_t
    osd_reply_sync_t sync;
    uint8_t buf[OSD_PACKET_SIZE];
 };
 extern const char* osd_op_names[];
--- a/osd_peering.cpp
+++ b/osd_peering.cpp
@ -1,234 +1,289 @@
 // Copyright (c) Vitaliy Filippov, 2019+
 // License: VNPL-1.0 (see README.md for details)
 #include <netinet/tcp.h>
 #include <sys/epoll.h>
 #include <algorithm>
 #include "base64.h"
 #include "osd.h"
 void osd_t::init_primary()
 {
    // Initial test version of clustering code requires exactly 2 peers
    // FIXME Hardcode
    std::string peerstr = config["peers"];
    while (peerstr.size())
    {
        int pos = peerstr.find(',');
        peers.push_back(parse_peer(pos < 0 ? peerstr : peerstr.substr(0, pos)));
        peerstr = pos < 0 ? std::string("") : peerstr.substr(pos+1);
        for (int i = 0; i < peers.size()-1; i++)
            if (peers[i].osd_num == peers[peers.size()-1].osd_num)
                throw std::runtime_error("same osd number "+std::to_string(peers[i].osd_num)+" specified twice in peers");
    }
    if (peers.size() < 2)
        throw std::runtime_error("run_primary requires at least 2 peers");
    pgs.push_back((pg_t){
        .state = PG_OFFLINE,
        .pg_cursize = 0,
        .pg_num = 1,
        .target_set = { 1, 2, 3 },
        .cur_set = { 1, 0, 0 },
    });
    pg_count = 1;
    peering_state = OSD_PEERING_PEERS;
 }
 osd_peer_def_t osd_t::parse_peer(std::string peer)
 {
    // OSD_NUM:IP:PORT
    int pos1 = peer.find(':');
    int pos2 = peer.find(':', pos1+1);
    if (pos1 < 0 || pos2 < 0)
        throw new std::runtime_error("OSD peer string must be in the form OSD_NUM:IP:PORT");
    osd_peer_def_t r;
    r.addr = peer.substr(pos1+1, pos2-pos1-1);
    std::string osd_num_str = peer.substr(0, pos1);
    std::string port_str = peer.substr(pos2+1);
    r.osd_num = strtoull(osd_num_str.c_str(), NULL, 10);
    if (!r.osd_num)
        throw new std::runtime_error("Could not parse OSD peer osd_num");
    r.port = strtoull(port_str.c_str(), NULL, 10);
    if (!r.port)
        throw new std::runtime_error("Could not parse OSD peer port");
    return r;
 }
 void osd_t::connect_peer(osd_num_t osd_num, const char *peer_host, int peer_port, std::function<void(osd_num_t, int)> callback)
 {
    struct sockaddr_in addr;
    int r;
    if ((r = inet_pton(AF_INET, peer_host, &addr.sin_addr)) != 1)
    {
        callback(osd_num, -EINVAL);
        return;
    }
    addr.sin_family = AF_INET;
    addr.sin_port = htons(peer_port ? peer_port : 11203);
    int peer_fd = socket(AF_INET, SOCK_STREAM, 0);
    if (peer_fd < 0)
    {
        callback(osd_num, -errno);
        return;
    }
    fcntl(peer_fd, F_SETFL, fcntl(peer_fd, F_GETFL, 0) | O_NONBLOCK);
    r = connect(peer_fd, (sockaddr*)&addr, sizeof(addr));
    if (r < 0 && errno != EINPROGRESS)
    {
        close(peer_fd);
        callback(osd_num, -errno);
        return;
    }
    clients[peer_fd] = (osd_client_t){
        .peer_addr = addr,
        .peer_port = peer_port,
        .peer_fd = peer_fd,
        .peer_state = PEER_CONNECTING,
        .connect_callback = callback,
        .osd_num = osd_num,
    };
    osd_peer_fds[osd_num] = peer_fd;
    // Add FD to epoll (EPOLLOUT for tracking connect() result)
    epoll_event ev;
    ev.data.fd = peer_fd;
    ev.events = EPOLLOUT | EPOLLIN | EPOLLRDHUP | EPOLLET;
    if (epoll_ctl(epoll_fd, EPOLL_CTL_ADD, peer_fd, &ev) < 0)
    {
        throw std::runtime_error(std::string("epoll_ctl: ") + strerror(errno));
    }
 }
 void osd_t::handle_connect_result(int peer_fd)
 {
    auto & cl = clients[peer_fd];
    osd_num_t osd_num = cl.osd_num;
    auto callback = cl.connect_callback;
    int result = 0;
    socklen_t result_len = sizeof(result);
    if (getsockopt(peer_fd, SOL_SOCKET, SO_ERROR, &result, &result_len) < 0)
    {
        result = errno;
    }
    if (result != 0)
    {
        stop_client(peer_fd);
        callback(osd_num, -result);
        return;
    }
    int one = 1;
    setsockopt(peer_fd, SOL_TCP, TCP_NODELAY, &one, sizeof(one));
    // Disable EPOLLOUT on this fd
    cl.peer_fd_index = ringloop->register_fd(peer_fd);
    cl.connect_callback = NULL;
    cl.peer_state = PEER_CONNECTED;
    epoll_event ev;
    ev.data.fd = peer_fd;
    ev.events = EPOLLIN | EPOLLRDHUP | EPOLLET;
    if (epoll_ctl(epoll_fd, EPOLL_CTL_MOD, peer_fd, &ev) < 0)
    {
        throw std::runtime_error(std::string("epoll_ctl: ") + strerror(errno));
    }
    callback(osd_num, peer_fd);
 }
 // Peering loop
 void osd_t::handle_peers()
 {
    if (peering_state & OSD_PEERING_PEERS)
    {
        for (int i = 0; i < peers.size(); i++)
        {
            if (osd_peer_fds.find(peers[i].osd_num) == osd_peer_fds.end() &&
                time(NULL) - peers[i].last_connect_attempt > 5) // FIXME hardcode 5
            {
                peers[i].last_connect_attempt = time(NULL);
                connect_peer(peers[i].osd_num, peers[i].addr.c_str(), peers[i].port, [this](osd_num_t osd_num, int peer_fd)
                {
                    // FIXME: Check peer config after connecting
                    if (peer_fd < 0)
                    {
                        printf("Failed to connect to peer OSD %lu: %s\n", osd_num, strerror(-peer_fd));
                        return;
                    }
                    printf("Connected with peer OSD %lu (fd %d)\n", clients[peer_fd].osd_num, peer_fd);
                    int i;
                    for (i = 0; i < peers.size(); i++)
                    {
                        if (osd_peer_fds.find(peers[i].osd_num) == osd_peer_fds.end())
                            break;
                    }
                    if (i >= peers.size())
                    {
                        // Connected to all peers
                        peering_state = peering_state & ~OSD_PEERING_PEERS;
                    }
                    repeer_pgs(osd_num, true);
                });
            }
        }
    }
    if (peering_state & OSD_PEERING_PGS)
    {
-        bool still = false;
+        bool still_doing_pgs = false;
-        for (auto & p: pgs)
+        for (int i = 0; i < pgs.size(); i++)
        {
-            if (p.second.state == PG_PEERING)
+            if (pgs[i].state == PG_PEERING)
            {
-                if (!p.second.peering_state->list_ops.size())
+                if (!pgs[i].peering_state->list_ops.size())
                {
-                    p.second.calc_object_states(log_level);
+                    pgs[i].calc_object_states();
                    report_pg_state(p.second);
                    incomplete_objects += p.second.incomplete_objects.size();
                    misplaced_objects += p.second.misplaced_objects.size();
                    // FIXME: degraded objects may currently include misplaced, too! Report them separately?
                    degraded_objects += p.second.degraded_objects.size();
                    if ((p.second.state & (PG_ACTIVE | PG_HAS_UNCLEAN)) == (PG_ACTIVE | PG_HAS_UNCLEAN))
                        peering_state = peering_state | OSD_FLUSHING_PGS;
                    else if (p.second.state & PG_ACTIVE)
                        peering_state = peering_state | OSD_RECOVERING;
                }
                else
                {
-                    still = true;
+                    still_doing_pgs = true;
                }
            }
        }
-        if (!still)
+        if (!still_doing_pgs)
        {
            // Done all PGs
            peering_state = peering_state & ~OSD_PEERING_PGS;
        }
    }
    if ((peering_state & OSD_FLUSHING_PGS) && !readonly)
    {
        bool still = false;
        for (auto & p: pgs)
        {
            if ((p.second.state & (PG_ACTIVE | PG_HAS_UNCLEAN)) == (PG_ACTIVE | PG_HAS_UNCLEAN))
            {
                if (!p.second.flush_batch)
                {
                    submit_pg_flush_ops(p.second);
                }
                still = true;
            }
        }
        if (!still)
        {
            peering_state = peering_state & ~OSD_FLUSHING_PGS | OSD_RECOVERING;
        }
    }
    if ((peering_state & OSD_RECOVERING) && !readonly)
    {
        if (!continue_recovery())
        {
            peering_state = peering_state & ~OSD_RECOVERING;
        }
    }
 }
-void osd_t::repeer_pgs(osd_num_t peer_osd)
+void osd_t::repeer_pgs(osd_num_t osd_num, bool is_connected)
 {
    // Re-peer affected PGs
-    for (auto & p: pgs)
+    // FIXME: We shouldn't rely just on target_set. Other OSDs may also contain PG data.
    osd_num_t real_osd = (is_connected ? osd_num : 0);
    for (int i = 0; i < pgs.size(); i++)
    {
        bool repeer = false;
-        if (p.second.state & (PG_PEERING | PG_ACTIVE | PG_INCOMPLETE))
+        for (int r = 0; r < pgs[i].target_set.size(); r++)
        {
-            for (osd_num_t pg_osd: p.second.all_peers)
+            if (pgs[i].target_set[r] == osd_num &&
                pgs[i].cur_set[r] != real_osd)
            {
-                if (pg_osd == peer_osd)
+                pgs[i].cur_set[r] = real_osd;
-                {
+                repeer = true;
-                    repeer = true;
+                break;
                    break;
                }
            }
            if (repeer)
            {
                // Repeer this pg
                printf("[PG %u] Repeer because of OSD %lu\n", p.second.pg_num, peer_osd);
                start_pg_peering(p.second);
            }
        }
        if (repeer)
        {
            // Repeer this pg
            printf("Repeer PG %d because of OSD %lu\n", i, osd_num);
            start_pg_peering(i);
            peering_state |= OSD_PEERING_PGS;
        }
    }
 }
 // Repeer on each connect/disconnect peer event
-void osd_t::start_pg_peering(pg_t & pg)
+void osd_t::start_pg_peering(int pg_idx)
 {
    auto & pg = pgs[pg_idx];
    pg.state = PG_PEERING;
    this->peering_state |= OSD_PEERING_PGS;
    report_pg_state(pg);
    // Reset PG state
    pg.cur_peers.clear();
    pg.state_dict.clear();
-    incomplete_objects -= pg.incomplete_objects.size();
+    pg.obj_states.clear();
    misplaced_objects -= pg.misplaced_objects.size();
    degraded_objects -= pg.degraded_objects.size();
    pg.incomplete_objects.clear();
    pg.misplaced_objects.clear();
    pg.degraded_objects.clear();
    pg.flush_actions.clear();
    pg.ver_override.clear();
    if (pg.flush_batch)
    {
        delete pg.flush_batch;
    }
    pg.flush_batch = NULL;
    for (auto p: pg.write_queue)
    {
        cancel_primary_write(p.second);
    }
    pg.write_queue.clear();
    uint64_t pg_stripe_size = st_cli.pool_config[pg.pool_id].pg_stripe_size;
    for (auto it = unstable_writes.begin(); it != unstable_writes.end(); )
    {
        // Forget this PG's unstable writes
        if (INODE_POOL(it->first.oid.inode) == pg.pool_id && map_to_pg(it->first.oid, pg_stripe_size) == pg.pg_num)
            unstable_writes.erase(it++);
        else
            it++;
    }
    dirty_pgs.erase({ .pool_id = pg.pool_id, .pg_num = pg.pg_num });
    // Drop connections of clients who have this PG in dirty_pgs
    if (immediate_commit != IMMEDIATE_ALL)
    {
        std::vector<int> to_stop;
        for (auto & cp: c_cli.clients)
        {
            if (cp.second.dirty_pgs.find({ .pool_id = pg.pool_id, .pg_num = pg.pg_num }) != cp.second.dirty_pgs.end())
            {
                to_stop.push_back(cp.first);
            }
        }
        for (auto peer_fd: to_stop)
        {
            c_cli.stop_client(peer_fd);
        }
    }
    // Calculate current write OSD set
    pg.pg_cursize = 0;
-    pg.cur_set.resize(pg.target_set.size());
+    for (int role = 0; role < pg.cur_set.size(); role++)
    pg.cur_loc_set.clear();
    for (int role = 0; role < pg.target_set.size(); role++)
    {
        pg.cur_set[role] = pg.target_set[role] == this->osd_num ||
            c_cli.osd_peer_fds.find(pg.target_set[role]) != c_cli.osd_peer_fds.end() ? pg.target_set[role] : 0;
        if (pg.cur_set[role] != 0)
        {
            pg.pg_cursize++;
            pg.cur_loc_set.push_back({
                .role = (uint64_t)role,
                .osd_num = pg.cur_set[role],
                .outdated = false,
            });
        }
    }
    if (pg.target_history.size())
    {
        // Refuse to start PG if no peers are available from any of the historical OSD sets
        // (PG history is kept up to the latest active+clean state)
        for (auto & history_set: pg.target_history)
        {
            bool found = false;
            for (auto history_osd: history_set)
            {
                if (history_osd != 0 && c_cli.osd_peer_fds.find(history_osd) != c_cli.osd_peer_fds.end())
                {
                    found = true;
                    break;
                }
            }
            if (!found)
            {
                pg.state = PG_INCOMPLETE;
                report_pg_state(pg);
                return;
            }
        }
    }
    if (pg.pg_cursize < pg.pg_minsize)
    {
        pg.state = PG_INCOMPLETE;
        report_pg_state(pg);
        return;
    }
    std::set<osd_num_t> cur_peers;
    for (auto pg_osd: pg.all_peers)
    {
        if (pg_osd == this->osd_num || c_cli.osd_peer_fds.find(pg_osd) != c_cli.osd_peer_fds.end())
        {
            cur_peers.insert(pg_osd);
        }
        else if (c_cli.wanted_peers.find(pg_osd) == c_cli.wanted_peers.end())
        {
            c_cli.connect_peer(pg_osd, st_cli.peer_states[pg_osd]);
        }
    }
    pg.cur_peers.insert(pg.cur_peers.begin(), cur_peers.begin(), cur_peers.end());
    if (pg.peering_state)
    {
-        // Adjust the peering operation that's still in progress - discard unneeded results
+        // Adjust the peering operation that's still in progress
-        for (auto it = pg.peering_state->list_ops.begin(); it != pg.peering_state->list_ops.end();)
+        for (auto it = pg.peering_state->list_ops.begin(); it != pg.peering_state->list_ops.end(); it++)
        {
-            if (pg.state == PG_INCOMPLETE || cur_peers.find(it->first) == cur_peers.end())
+            int role;
            for (role = 0; role < pg.cur_set.size(); role++)
            {
                if (pg.cur_set[role] == it->first)
                    break;
            }
            if (pg.state == PG_INCOMPLETE || role >= pg.cur_set.size())
            {
                // Discard the result after completion, which, chances are, will be unsuccessful
-                discard_list_subop(it->second);
+                auto list_op = it->second;
                if (list_op->peer_fd == 0)
                {
                    // Self
                    list_op->bs_op->callback = [list_op](blockstore_op_t *bs_op)
                    {
                        if (list_op->bs_op->buf)
                            free(list_op->bs_op->buf);
                        delete list_op;
                    };
                }
                else
                {
                    // Peer
                    list_op->callback = [](osd_op_t *list_op)
                    {
                        delete list_op;
                    };
                }
                pg.peering_state->list_ops.erase(it);
                it = pg.peering_state->list_ops.begin();
            }
            else
                it++;
        }
-        for (auto it = pg.peering_state->list_results.begin(); it != pg.peering_state->list_results.end();)
+        for (auto it = pg.peering_state->list_results.begin(); it != pg.peering_state->list_results.end(); it++)
        {
-            if (pg.state == PG_INCOMPLETE || cur_peers.find(it->first) == cur_peers.end())
+            int role;
            for (role = 0; role < pg.cur_set.size(); role++)
            {
                if (pg.cur_set[role] == it->first)
                    break;
            }
            if (pg.state == PG_INCOMPLETE || role >= pg.cur_set.size())
            {
                if (it->second.buf)
                {
@ -237,8 +292,6 @@ void osd_t::start_pg_peering(pg_t & pg)
                pg.peering_state->list_results.erase(it);
                it = pg.peering_state->list_results.begin();
            }
            else
                it++;
        }
    }
    if (pg.state == PG_INCOMPLETE)
@ -248,297 +301,107 @@ void osd_t::start_pg_peering(pg_t & pg)
            delete pg.peering_state;
            pg.peering_state = NULL;
        }
        printf("PG %d is incomplete\n", pg.pg_num);
        return;
    }
    if (!pg.peering_state)
    {
        pg.peering_state = new pg_peering_state_t();
        pg.peering_state->pool_id = pg.pool_id;
        pg.peering_state->pg_num = pg.pg_num;
    }
-    for (osd_num_t peer_osd: cur_peers)
+    auto ps = pg.peering_state;
    for (int role = 0; role < pg.cur_set.size(); role++)
    {
-        if (pg.peering_state->list_ops.find(peer_osd) != pg.peering_state->list_ops.end() ||
+        osd_num_t role_osd = pg.cur_set[role];
-            pg.peering_state->list_results.find(peer_osd) != pg.peering_state->list_results.end())
+        if (!role_osd)
        {
            continue;
        }
-        submit_sync_and_list_subop(peer_osd, pg.peering_state);
+        if (ps->list_ops.find(role_osd) != ps->list_ops.end() ||
            ps->list_results.find(role_osd) != ps->list_results.end())
        {
            continue;
        }
        if (role_osd == this->osd_num)
        {
            // Self
            osd_op_t *op = new osd_op_t();
            op->op_type = 0;
            op->peer_fd = 0;
            op->bs_op = new blockstore_op_t();
            op->bs_op->opcode = BS_OP_LIST;
            op->bs_op->oid.stripe = parity_block_size;
            op->bs_op->len = pg_count,
            op->bs_op->offset = pg.pg_num-1,
            op->bs_op->callback = [ps, op, role_osd](blockstore_op_t *bs_op)
            {
                if (op->bs_op->retval < 0)
                {
                    throw std::runtime_error("local OP_LIST failed");
                }
                printf(
                    "Got object list from OSD %lu (local): %d object versions (%lu of them stable)\n",
                    role_osd, bs_op->retval, bs_op->version
                );
                ps->list_results[role_osd] = {
                    .buf = (obj_ver_id*)op->bs_op->buf,
                    .total_count = (uint64_t)op->bs_op->retval,
                    .stable_count = op->bs_op->version,
                };
                ps->list_done++;
                ps->list_ops.erase(role_osd);
                delete op;
            };
            bs->enqueue_op(op->bs_op);
            ps->list_ops[role_osd] = op;
        }
        else
        {
            // Peer
            auto & cl = clients[osd_peer_fds[role_osd]];
            osd_op_t *op = new osd_op_t();
            op->op_type = OSD_OP_OUT;
            op->send_list.push_back(op->req.buf, OSD_PACKET_SIZE);
            op->peer_fd = cl.peer_fd;
            op->req = {
                .sec_list = {
                    .header = {
                        .magic = SECONDARY_OSD_OP_MAGIC,
                        .id = this->next_subop_id++,
                        .opcode = OSD_OP_SECONDARY_LIST,
                    },
                    .list_pg = pg.pg_num,
                    .pg_count = pg_count,
                    .parity_block_size = parity_block_size,
                },
            };
            op->callback = [this, ps, role_osd](osd_op_t *op)
            {
                if (op->reply.hdr.retval < 0)
                {
                    printf("Failed to get object list from OSD %lu (retval=%ld), disconnecting peer\n", role_osd, op->reply.hdr.retval);
                    ps->list_ops.erase(role_osd);
                    stop_client(op->peer_fd);
                    delete op;
                    return;
                }
                printf(
                    "Got object list from OSD %lu: %ld object versions (%lu of them stable)\n",
                    role_osd, op->reply.hdr.retval, op->reply.sec_list.stable_count
                );
                ps->list_results[role_osd] = {
                    .buf = (obj_ver_id*)op->buf,
                    .total_count = (uint64_t)op->reply.hdr.retval,
                    .stable_count = op->reply.sec_list.stable_count,
                };
                // set op->buf to NULL so it doesn't get freed
                op->buf = NULL;
                ps->list_done++;
                ps->list_ops.erase(role_osd);
                delete op;
            };
            outbox_push(cl, op);
            ps->list_ops[role_osd] = op;
        }
    }
    ringloop->wakeup();
 }
 void osd_t::submit_sync_and_list_subop(osd_num_t role_osd, pg_peering_state_t *ps)
 {
    // Sync before listing, if not readonly
    if (readonly)
    {
        submit_list_subop(role_osd, ps);
    }
    else if (role_osd == this->osd_num)
    {
        // Self
        osd_op_t *op = new osd_op_t();
        op->op_type = 0;
        op->peer_fd = 0;
        clock_gettime(CLOCK_REALTIME, &op->tv_begin);
        op->bs_op = new blockstore_op_t();
        op->bs_op->opcode = BS_OP_SYNC;
        op->bs_op->callback = [this, ps, op, role_osd](blockstore_op_t *bs_op)
        {
            if (bs_op->retval < 0)
            {
                printf("Local OP_SYNC failed: %d (%s)\n", bs_op->retval, strerror(-bs_op->retval));
                force_stop(1);
                return;
            }
            add_bs_subop_stats(op);
            delete op->bs_op;
            op->bs_op = NULL;
            delete op;
            ps->list_ops.erase(role_osd);
            submit_list_subop(role_osd, ps);
        };
        bs->enqueue_op(op->bs_op);
        ps->list_ops[role_osd] = op;
    }
    else
    {
        // Peer
        auto & cl = c_cli.clients.at(c_cli.osd_peer_fds[role_osd]);
        osd_op_t *op = new osd_op_t();
        op->op_type = OSD_OP_OUT;
        op->peer_fd = cl.peer_fd;
        op->req = {
            .sec_sync = {
                .header = {
                    .magic = SECONDARY_OSD_OP_MAGIC,
                    .id = c_cli.next_subop_id++,
                    .opcode = OSD_OP_SEC_SYNC,
                },
            },
        };
        op->callback = [this, ps, role_osd](osd_op_t *op)
        {
            if (op->reply.hdr.retval < 0)
            {
                // FIXME: Mark peer as failed and don't reconnect immediately after dropping the connection
                printf("Failed to sync OSD %lu: %ld (%s), disconnecting peer\n", role_osd, op->reply.hdr.retval, strerror(-op->reply.hdr.retval));
                ps->list_ops.erase(role_osd);
                c_cli.stop_client(op->peer_fd);
                delete op;
                return;
            }
            delete op;
            ps->list_ops.erase(role_osd);
            submit_list_subop(role_osd, ps);
        };
        c_cli.outbox_push(op);
        ps->list_ops[role_osd] = op;
    }
 }
 void osd_t::submit_list_subop(osd_num_t role_osd, pg_peering_state_t *ps)
 {
    if (role_osd == this->osd_num)
    {
        // Self
        osd_op_t *op = new osd_op_t();
        op->op_type = 0;
        op->peer_fd = 0;
        clock_gettime(CLOCK_REALTIME, &op->tv_begin);
        op->bs_op = new blockstore_op_t();
        op->bs_op->opcode = BS_OP_LIST;
        op->bs_op->oid.stripe = st_cli.pool_config[ps->pool_id].pg_stripe_size;
        op->bs_op->oid.inode = ((uint64_t)ps->pool_id << (64 - POOL_ID_BITS));
        op->bs_op->version = ((uint64_t)(ps->pool_id+1) << (64 - POOL_ID_BITS)) - 1;
        op->bs_op->len = pg_counts[ps->pool_id];
        op->bs_op->offset = ps->pg_num-1;
        op->bs_op->callback = [this, ps, op, role_osd](blockstore_op_t *bs_op)
        {
            if (op->bs_op->retval < 0)
            {
                throw std::runtime_error("local OP_LIST failed");
            }
            add_bs_subop_stats(op);
            printf(
                "[PG %u] Got object list from OSD %lu (local): %d object versions (%lu of them stable)\n",
                ps->pg_num, role_osd, bs_op->retval, bs_op->version
            );
            ps->list_results[role_osd] = {
                .buf = (obj_ver_id*)op->bs_op->buf,
                .total_count = (uint64_t)op->bs_op->retval,
                .stable_count = op->bs_op->version,
            };
            ps->list_ops.erase(role_osd);
            delete op->bs_op;
            op->bs_op = NULL;
            delete op;
        };
        bs->enqueue_op(op->bs_op);
        ps->list_ops[role_osd] = op;
    }
    else
    {
        // Peer
        osd_op_t *op = new osd_op_t();
        op->op_type = OSD_OP_OUT;
        op->peer_fd = c_cli.osd_peer_fds[role_osd];
        op->req = {
            .sec_list = {
                .header = {
                    .magic = SECONDARY_OSD_OP_MAGIC,
                    .id = c_cli.next_subop_id++,
                    .opcode = OSD_OP_SEC_LIST,
                },
                .list_pg = ps->pg_num,
                .pg_count = pg_counts[ps->pool_id],
                .pg_stripe_size = st_cli.pool_config[ps->pool_id].pg_stripe_size,
                .min_inode = ((uint64_t)(ps->pool_id) << (64 - POOL_ID_BITS)),
                .max_inode = ((uint64_t)(ps->pool_id+1) << (64 - POOL_ID_BITS)) - 1,
            },
        };
        op->callback = [this, ps, role_osd](osd_op_t *op)
        {
            if (op->reply.hdr.retval < 0)
            {
                printf("Failed to get object list from OSD %lu (retval=%ld), disconnecting peer\n", role_osd, op->reply.hdr.retval);
                ps->list_ops.erase(role_osd);
                c_cli.stop_client(op->peer_fd);
                delete op;
                return;
            }
            printf(
                "[PG %u] Got object list from OSD %lu: %ld object versions (%lu of them stable)\n",
                ps->pg_num, role_osd, op->reply.hdr.retval, op->reply.sec_list.stable_count
            );
            ps->list_results[role_osd] = {
                .buf = (obj_ver_id*)op->buf,
                .total_count = (uint64_t)op->reply.hdr.retval,
                .stable_count = op->reply.sec_list.stable_count,
            };
            // set op->buf to NULL so it doesn't get freed
            op->buf = NULL;
            ps->list_ops.erase(role_osd);
            delete op;
        };
        c_cli.outbox_push(op);
        ps->list_ops[role_osd] = op;
    }
 }
 void osd_t::discard_list_subop(osd_op_t *list_op)
 {
    if (list_op->peer_fd == 0)
    {
        // Self
        list_op->bs_op->callback = [list_op](blockstore_op_t *bs_op)
        {
            if (list_op->bs_op->buf)
                free(list_op->bs_op->buf);
            delete list_op->bs_op;
            list_op->bs_op = NULL;
            delete list_op;
        };
    }
    else
    {
        // Peer
        list_op->callback = [](osd_op_t *list_op)
        {
            delete list_op;
        };
    }
 }
 bool osd_t::stop_pg(pg_t & pg)
 {
    if (pg.peering_state)
    {
        // Stop peering
        for (auto it = pg.peering_state->list_ops.begin(); it != pg.peering_state->list_ops.end();)
        {
            discard_list_subop(it->second);
        }
        for (auto it = pg.peering_state->list_results.begin(); it != pg.peering_state->list_results.end();)
        {
            if (it->second.buf)
            {
                free(it->second.buf);
            }
        }
        delete pg.peering_state;
        pg.peering_state = NULL;
    }
    if (!(pg.state & PG_ACTIVE))
    {
        return false;
    }
    pg.state = pg.state & ~PG_ACTIVE | PG_STOPPING;
    if (pg.inflight == 0 && !pg.flush_batch)
    {
        finish_stop_pg(pg);
    }
    else
    {
        report_pg_state(pg);
    }
    return true;
 }
 void osd_t::finish_stop_pg(pg_t & pg)
 {
    pg.state = PG_OFFLINE;
    report_pg_state(pg);
 }
 void osd_t::report_pg_state(pg_t & pg)
 {
    pg.print_state();
    this->pg_state_dirty.insert({ .pool_id = pg.pool_id, .pg_num = pg.pg_num });
    if (pg.state == PG_ACTIVE && (pg.target_history.size() > 0 || pg.all_peers.size() > pg.target_set.size()))
    {
        // Clear history of active+clean PGs
        pg.history_changed = true;
        pg.target_history.clear();
        pg.all_peers = pg.target_set;
        pg.cur_peers = pg.target_set;
    }
    else if (pg.state == (PG_ACTIVE|PG_LEFT_ON_DEAD))
    {
        // Clear history of active+left_on_dead PGs, but leave dead OSDs in all_peers
        pg.history_changed = true;
        pg.target_history.clear();
        std::set<osd_num_t> dead_peers;
        for (auto pg_osd: pg.all_peers)
        {
            dead_peers.insert(pg_osd);
        }
        for (auto pg_osd: pg.cur_peers)
        {
            dead_peers.erase(pg_osd);
        }
        for (auto pg_osd: pg.target_set)
        {
            if (pg_osd)
            {
                dead_peers.insert(pg_osd);
            }
        }
        pg.all_peers.clear();
        pg.all_peers.insert(pg.all_peers.begin(), dead_peers.begin(), dead_peers.end());
        pg.cur_peers.clear();
        for (auto pg_osd: pg.target_set)
        {
            if (pg_osd)
            {
                pg.cur_peers.push_back(pg_osd);
            }
        }
    }
    if (pg.state == PG_OFFLINE && !this->pg_config_applied)
    {
        apply_pg_config();
    }
    report_pg_states();
 }
--- a/osd_peering_pg.cpp
+++ b/osd_peering_pg.cpp
@ -1,420 +1,159 @@
 // Copyright (c) Vitaliy Filippov, 2019+
 // License: VNPL-1.0 (see README.md for details)
 #include "osd_peering_pg.h"
-struct obj_ver_role
+void pg_t::remember_object(pg_obj_state_check_t &st, std::vector<obj_ver_role> &all)
 {
-    object_id oid;
+    auto & pg = *this;
    uint64_t version;
    uint64_t osd_num;
    bool is_stable;
 };
 inline bool operator < (const obj_ver_role & a, const obj_ver_role & b)
 {
    // ORDER BY inode ASC, stripe & ~STRIPE_MASK ASC, version DESC, role ASC, osd_num ASC
    return a.oid.inode < b.oid.inode || a.oid.inode == b.oid.inode && (
        (a.oid.stripe & ~STRIPE_MASK) < (b.oid.stripe & ~STRIPE_MASK) ||
        (a.oid.stripe & ~STRIPE_MASK) == (b.oid.stripe & ~STRIPE_MASK) && (
            a.version > b.version ||
            a.version == b.version && (
                a.oid.stripe < b.oid.stripe ||
                a.oid.stripe == b.oid.stripe && a.osd_num < b.osd_num
            )
        )
    );
 }
 struct obj_piece_ver_t
 {
    uint64_t max_ver = 0;
    uint64_t stable_ver = 0;
    uint64_t max_target = 0;
 };
 struct pg_obj_state_check_t
 {
    pg_t *pg;
    bool replicated = false;
    std::vector<obj_ver_role> list;
    int list_pos;
    int obj_start = 0, obj_end = 0, ver_start = 0, ver_end = 0;
    object_id oid = { 0 };
    uint64_t max_ver = 0;
    uint64_t last_ver = 0;
    uint64_t target_ver = 0;
    uint64_t n_copies = 0, has_roles = 0, n_roles = 0, n_stable = 0, n_mismatched = 0;
    uint64_t n_unstable = 0, n_invalid = 0;
    pg_osd_set_t osd_set;
    int log_level;
    void walk();
    void start_object();
    void handle_version();
    void finish_object();
 };
 void pg_obj_state_check_t::walk()
 {
    pg->clean_count = 0;
    pg->total_count = 0;
    pg->state = 0;
    for (list_pos = 0; list_pos < list.size(); list_pos++)
    {
        if (oid.inode != list[list_pos].oid.inode ||
            oid.stripe != (list[list_pos].oid.stripe & ~STRIPE_MASK))
        {
            if (oid.inode != 0)
            {
                finish_object();
            }
            start_object();
        }
        handle_version();
    }
    if (oid.inode != 0)
    {
        finish_object();
    }
    if (pg->state & PG_HAS_INVALID)
    {
        // Stop PGs with "invalid" objects
        pg->state = PG_INCOMPLETE | PG_HAS_INVALID;
        return;
    }
    if (pg->pg_cursize < pg->pg_size)
    {
        pg->state |= PG_DEGRADED;
    }
    pg->state |= PG_ACTIVE;
    if (pg->state == PG_ACTIVE && pg->cur_peers.size() < pg->all_peers.size())
    {
        pg->state |= PG_LEFT_ON_DEAD;
    }
 }
 void pg_obj_state_check_t::start_object()
 {
    obj_start = list_pos;
    oid = { .inode = list[list_pos].oid.inode, .stripe = list[list_pos].oid.stripe & ~STRIPE_MASK };
    last_ver = max_ver = list[list_pos].version;
    target_ver = 0;
    ver_start = list_pos;
    has_roles = n_copies = n_roles = n_stable = n_mismatched = 0;
    n_unstable = n_invalid = 0;
 }
 void pg_obj_state_check_t::handle_version()
 {
    if (!target_ver && last_ver != list[list_pos].version && (n_stable > 0 || n_roles >= pg->pg_minsize))
    {
        // Version is either stable or recoverable
        target_ver = last_ver;
        ver_end = list_pos;
    }
    if (!target_ver)
    {
        if (last_ver != list[list_pos].version)
        {
            ver_start = list_pos;
            has_roles = n_copies = n_roles = n_stable = n_mismatched = 0;
            last_ver = list[list_pos].version;
        }
        unsigned replica = (list[list_pos].oid.stripe & STRIPE_MASK);
        n_copies++;
        if (replicated && replica > 0 || replica >= pg->pg_size)
        {
            n_invalid++;
        }
        else
        {
            if (list[list_pos].is_stable)
            {
                n_stable++;
            }
            if (replicated)
            {
                int i;
                for (i = 0; i < pg->cur_set.size(); i++)
                {
                    if (pg->cur_set[i] == list[list_pos].osd_num)
                    {
                        break;
                    }
                }
                if (i == pg->cur_set.size())
                {
                    n_mismatched++;
                }
            }
            else
            {
                if (pg->cur_set[replica] != list[list_pos].osd_num)
                {
                    n_mismatched++;
                }
                if (!(has_roles & (1 << replica)))
                {
                    has_roles = has_roles | (1 << replica);
                    n_roles++;
                }
            }
        }
    }
    if (!list[list_pos].is_stable)
    {
        n_unstable++;
    }
 }
 void pg_obj_state_check_t::finish_object()
 {
    if (!target_ver && (n_stable > 0 || n_roles >= pg->pg_minsize))
    {
        // Version is either stable or recoverable
        target_ver = last_ver;
        ver_end = list_pos;
    }
    obj_end = list_pos;
    // Remember the decision
    uint64_t state = 0;
-    if (n_invalid > 0)
+    if (st.n_roles == pg.pg_cursize)
    {
-        // It's not allowed to change the replication scheme for a pool other than by recreating it
+        if (st.n_matched == pg.pg_cursize)
-        // So we must bring the PG offline
+            state = OBJ_CLEAN;
        state = OBJ_INCOMPLETE;
        pg->state |= PG_HAS_INVALID;
        pg->total_count++;
        return;
    }
    if (n_unstable > 0)
    {
        pg->state |= PG_HAS_UNCLEAN;
        std::unordered_map<obj_piece_id_t, obj_piece_ver_t> pieces;
        for (int i = obj_start; i < obj_end; i++)
        {
            auto & pcs = pieces[(obj_piece_id_t){ .oid = list[i].oid, .osd_num = list[i].osd_num }];
            if (!pcs.max_ver)
            {
                pcs.max_ver = list[i].version;
            }
            if (list[i].is_stable && !pcs.stable_ver)
            {
                pcs.stable_ver = list[i].version;
            }
            if (list[i].version <= target_ver && !pcs.max_target)
            {
                pcs.max_target = list[i].version;
            }
        }
        for (auto pp: pieces)
        {
            auto & pcs = pp.second;
            if (pcs.stable_ver < pcs.max_ver)
            {
                auto & act = pg->flush_actions[pp.first];
                // osd_set doesn't include rollback/stable states, so don't include them in the state code either
                if (pcs.max_ver > target_ver)
                {
                    act.rollback = true;
                    act.rollback_to = pcs.max_target;
                }
                if (pcs.stable_ver < (pcs.max_ver > target_ver ? pcs.max_target : pcs.max_ver))
                {
                    act.make_stable = true;
                    act.stable_to = pcs.max_ver > target_ver ? pcs.max_target : pcs.max_ver;
                }
            }
        }
    }
    if (!target_ver)
    {
        return;
    }
    if (!replicated && n_roles < pg->pg_minsize)
    {
        if (log_level > 1)
        {
            printf("Object is incomplete: inode=%lu stripe=%lu version=%lu/%lu\n", oid.inode, oid.stripe, target_ver, max_ver);
        }
        state = OBJ_INCOMPLETE;
        pg->state = pg->state | PG_HAS_INCOMPLETE;
    }
    else if ((replicated ? n_copies : n_roles) < pg->pg_cursize)
    {
        if (log_level > 1)
        {
            printf("Object is degraded: inode=%lu stripe=%lu version=%lu/%lu\n", oid.inode, oid.stripe, target_ver, max_ver);
        }
        state = OBJ_DEGRADED;
        pg->state = pg->state | PG_HAS_DEGRADED;
    }
    else if (n_mismatched > 0)
    {
        if (log_level > 1 && (replicated || n_roles >= pg->pg_cursize))
        {
            printf("Object is misplaced: inode=%lu stripe=%lu version=%lu/%lu\n", oid.inode, oid.stripe, target_ver, max_ver);
        }
        state |= OBJ_MISPLACED;
        pg->state = pg->state | PG_HAS_MISPLACED;
    }
    if (log_level > 1 && ((replicated ? n_copies : n_roles) < pg->pg_cursize || n_mismatched > 0))
    {
        if (log_level > 2)
        {
            for (int i = obj_start; i < obj_end; i++)
            {
                printf("v%lu present on: osd %lu, role %ld%s\n", list[i].version, list[i].osd_num,
                    (list[i].oid.stripe & STRIPE_MASK), list[i].is_stable ? " (stable)" : "");
            }
        }
        else
        {
-            for (int i = ver_start; i < ver_end; i++)
+            state = OBJ_MISPLACED;
-            {
+            pg.state = pg.state | PG_HAS_MISPLACED;
                printf("Target version present on: osd %lu, role %ld%s\n", list[i].osd_num,
                    (list[i].oid.stripe & STRIPE_MASK), list[i].is_stable ? " (stable)" : "");
            }
        }
    }
-    pg->total_count++;
+    else if (st.n_roles < pg.pg_minsize)
    if (state != 0 || ver_end < obj_end)
    {
-        osd_set.clear();
+        printf("Object is unfound: inode=%lu stripe=%lu version=%lu/%lu\n", st.oid.inode, st.oid.stripe, st.target_ver, st.max_ver);
-        for (int i = ver_start; i < ver_end; i++)
+        state = OBJ_INCOMPLETE;
-        {
+        pg.state = pg.state | PG_HAS_UNFOUND;
            osd_set.push_back((pg_obj_loc_t){
                .role = (list[i].oid.stripe & STRIPE_MASK),
                .osd_num = list[i].osd_num,
                .outdated = false,
            });
        }
    }
    if (ver_end < obj_end)
    {
        // Check for outdated versions not present in the current target OSD set
        for (int i = ver_end; i < obj_end; i++)
        {
            int j;
            for (j = 0; j < osd_set.size(); j++)
            {
                if (osd_set[j].osd_num == list[i].osd_num)
                {
                    break;
                }
            }
            if (j >= osd_set.size() && pg->cur_set[list[i].oid.stripe & STRIPE_MASK] != list[i].osd_num)
            {
                osd_set.push_back((pg_obj_loc_t){
                    .role = (list[i].oid.stripe & STRIPE_MASK),
                    .osd_num = list[i].osd_num,
                    .outdated = true,
                });
                if (!(state & (OBJ_INCOMPLETE | OBJ_DEGRADED)))
                {
                    state |= OBJ_MISPLACED;
                    pg->state = pg->state | PG_HAS_MISPLACED;
                }
            }
        }
    }
    if (target_ver < max_ver)
    {
        pg->ver_override[oid] = target_ver;
    }
    if (state == 0)
    {
        pg->clean_count++;
    }
    else
    {
-        auto it = pg->state_dict.find(osd_set);
+        printf("Object is degraded: inode=%lu stripe=%lu version=%lu/%lu\n", st.oid.inode, st.oid.stripe, st.target_ver, st.max_ver);
-        if (it == pg->state_dict.end())
+        state = OBJ_DEGRADED;
        pg.state = pg.state | PG_HAS_DEGRADED;
    }
    if (st.n_copies > pg.pg_size)
    {
        state |= OBJ_OVERCOPIED;
        pg.state = pg.state | PG_HAS_UNCLEAN;
    }
    if (st.n_stable < st.n_copies)
    {
        state |= OBJ_NEEDS_STABLE;
        pg.state = pg.state | PG_HAS_UNCLEAN;
    }
    if (st.target_ver < st.max_ver || st.has_old_unstable)
    {
        state |= OBJ_NEEDS_ROLLBACK;
        pg.state = pg.state | PG_HAS_UNCLEAN;
        pg.ver_override[st.oid] = st.target_ver;
    }
    if (st.is_buggy)
    {
        state |= OBJ_BUGGY;
        // FIXME: bring pg offline
        throw std::runtime_error("buggy object state");
    }
    if (state != OBJ_CLEAN)
    {
        st.osd_set.clear();
        for (int i = st.ver_start; i < st.ver_end; i++)
        {
            st.osd_set.push_back((pg_obj_loc_t){
                .role = (all[i].oid.stripe & STRIPE_MASK),
                .osd_num = all[i].osd_num,
                .stable = all[i].is_stable,
            });
        }
        std::sort(st.osd_set.begin(), st.osd_set.end());
        auto it = pg.state_dict.find(st.osd_set);
        if (it == pg.state_dict.end())
        {
            std::vector<uint64_t> read_target;
-            if (replicated)
+            read_target.resize(pg.pg_size);
            for (int i = 0; i < pg.pg_size; i++)
            {
-                for (auto & o: osd_set)
+                read_target[i] = 0;
                {
                    if (!o.outdated)
                    {
                        read_target.push_back(o.osd_num);
                    }
                }
                while (read_target.size() < pg->pg_size)
                {
                    // FIXME: This is because we then use .data() and assume it's at least <pg_size> long
                    read_target.push_back(0);
                }
            }
-            else
+            for (auto & o: st.osd_set)
            {
-                read_target.resize(pg->pg_size);
+                read_target[o.role] = o.osd_num;
                for (int i = 0; i < pg->pg_size; i++)
                {
                    read_target[i] = 0;
                }
                for (auto & o: osd_set)
                {
                    if (!o.outdated)
                    {
                        read_target[o.role] = o.osd_num;
                    }
                }
            }
-            pg->state_dict[osd_set] = {
+            pg.state_dict[st.osd_set] = {
                .read_target = read_target,
-                .osd_set = osd_set,
+                .osd_set = st.osd_set,
                .state = state,
                .object_count = 1,
            };
-            it = pg->state_dict.find(osd_set);
+            it = pg.state_dict.find(st.osd_set);
        }
        else
        {
            it->second.object_count++;
        }
-        if (state & OBJ_INCOMPLETE)
+        pg.obj_states[st.oid] = &it->second;
        if (st.target_ver < st.max_ver)
        {
-            pg->incomplete_objects[oid] = &it->second;
+            pg.ver_override[st.oid] = st.target_ver;
        }
-        else if (state & OBJ_DEGRADED)
+        if (state & (OBJ_NEEDS_ROLLBACK | OBJ_NEEDS_STABLE))
        {
-            pg->degraded_objects[oid] = &it->second;
+            spp::sparse_hash_map<obj_piece_id_t, obj_piece_ver_t> pieces;
-        }
+            for (int i = st.obj_start; i < st.obj_end; i++)
-        else
+            {
-        {
+                auto & pcs = pieces[(obj_piece_id_t){ .oid = all[i].oid, .osd_num = all[i].osd_num }];
-            pg->misplaced_objects[oid] = &it->second;
+                if (!pcs.max_ver)
                {
                    pcs.max_ver = all[i].version;
                }
                if (all[i].is_stable && !pcs.stable_ver)
                {
                    pcs.stable_ver = all[i].version;
                }
            }
            for (auto pp: pieces)
            {
                auto & pcs = pp.second;
                if (pcs.stable_ver < pcs.max_ver)
                {
                    auto & act = obj_stab_actions[pp.first];
                    if (pcs.max_ver > st.target_ver)
                    {
                        act.rollback = true;
                        act.rollback_to = st.target_ver;
                    }
                    else if (pcs.max_ver < st.target_ver && pcs.stable_ver < pcs.max_ver)
                    {
                        act.rollback = true;
                        act.rollback_to = pcs.stable_ver;
                    }
                    if (pcs.max_ver >= st.target_ver && pcs.stable_ver < st.target_ver)
                    {
                        act.make_stable = true;
                        act.stable_to = st.target_ver;
                    }
                }
            }
        }
    }
    else
        pg.clean_count++;
    pg.total_count++;
 }
 // FIXME: Write at least some tests for this function
-void pg_t::calc_object_states(int log_level)
+void pg_t::calc_object_states()
 {
    auto & pg = *this;
    // Copy all object lists into one array
-    pg_obj_state_check_t st;
+    std::vector<obj_ver_role> all;
-    st.log_level = log_level;
+    auto ps = pg.peering_state;
    st.pg = this;
    st.replicated = (this->scheme == POOL_SCHEME_REPLICATED);
    auto ps = peering_state;
    epoch = 0;
    for (auto it: ps->list_results)
    {
        auto nstab = it.second.stable_count;
        auto n = it.second.total_count;
        auto osd_num = it.first;
-        uint64_t start = st.list.size();
+        uint64_t start = all.size();
-        st.list.resize(start + n);
+        all.resize(start + n);
        obj_ver_id *ov = it.second.buf;
        for (uint64_t i = 0; i < n; i++, ov++)
        {
-            if ((ov->version >> (64-PG_EPOCH_BITS)) > epoch)
+            all[start+i] = {
            {
                epoch = (ov->version >> (64-PG_EPOCH_BITS));
            }
            st.list[start+i] = {
                .oid = ov->oid,
                .version = ov->version,
                .osd_num = osd_num,
@ -426,33 +165,101 @@ void pg_t::calc_object_states(int log_level)
    }
    ps->list_results.clear();
    // Sort
-    std::sort(st.list.begin(), st.list.end());
+    std::sort(all.begin(), all.end());
    // Walk over it and check object states
-    st.walk();
+    pg.clean_count = 0;
-    if (this->state & (PG_DEGRADED|PG_LEFT_ON_DEAD))
+    pg.total_count = 0;
    pg.state = 0;
    int replica = 0;
    pg_obj_state_check_t st;
    for (int i = 0; i < all.size(); i++)
    {
-        assert(epoch != ((1ul << PG_EPOCH_BITS)-1));
+        if (st.oid.inode != all[i].oid.inode ||
-        epoch++;
+            st.oid.stripe != (all[i].oid.stripe & ~STRIPE_MASK))
        {
            if (st.oid.inode != 0)
            {
                // Remember object state
                st.obj_end = st.ver_end = i;
                remember_object(st, all);
            }
            st.obj_start = st.ver_start = i;
            st.oid = { .inode = all[i].oid.inode, .stripe = all[i].oid.stripe & ~STRIPE_MASK };
            st.max_ver = st.target_ver = all[i].version;
            st.has_roles = st.n_copies = st.n_roles = st.n_stable = st.n_matched = 0;
            st.is_buggy = st.has_old_unstable = false;
        }
        else if (st.target_ver != all[i].version)
        {
            if (st.n_stable > 0 || st.n_roles >= pg.pg_minsize)
            {
                // Last processed version is either recoverable or stable, choose it as target and skip previous versions
                st.ver_end = i;
                i++;
                while (i < all.size() && st.oid.inode == all[i].oid.inode &&
                    st.oid.stripe == (all[i].oid.stripe & ~STRIPE_MASK))
                {
                    if (!all[i].is_stable)
                    {
                        st.has_old_unstable = true;
                    }
                    i++;
                }
                st.obj_end = i;
                i--;
                continue;
            }
            else
            {
                // Last processed version is unstable and unrecoverable
                // We'll know that because target_ver < max_ver
                st.ver_start = i;
                st.target_ver = all[i].version;
                st.has_roles = st.n_copies = st.n_roles = st.n_stable = st.n_matched = 0;
            }
        }
        replica = (all[i].oid.stripe & STRIPE_MASK);
        st.n_copies++;
        if (replica >= pg.pg_size)
        {
            // FIXME In the future, check it against the PG epoch number to handle replication factor/scheme changes
            st.is_buggy = true;
        }
        else
        {
            if (all[i].is_stable)
            {
                st.n_stable++;
            }
            if (pg.cur_set[replica] == all[i].osd_num)
            {
                st.n_matched++;
            }
            if (!(st.has_roles & (1 << replica)))
            {
                st.has_roles = st.has_roles | (1 << replica);
                st.n_roles++;
            }
        }
    }
    if (st.oid.inode != 0)
    {
        // Remember object state
        st.obj_end = st.ver_end = all.size();
        remember_object(st, all);
    }
    if (pg.pg_cursize < pg.pg_size)
    {
        pg.state = pg.state | PG_DEGRADED;
    }
 }
 void pg_t::print_state()
 {
    printf(
-        "[PG %u] is %s%s%s%s%s%s%s%s%s%s%s%s%s (%lu objects)\n", pg_num,
+        "PG %u is active%s%s%s%s%s (%lu objects)\n", pg.pg_num,
-        (state & PG_STARTING) ? "starting" : "",
+        (pg.state & PG_DEGRADED) ? " + degraded" : "",
-        (state & PG_OFFLINE) ? "offline" : "",
+        (pg.state & PG_HAS_UNFOUND) ? " + has_unfound" : "",
-        (state & PG_PEERING) ? "peering" : "",
+        (pg.state & PG_HAS_DEGRADED) ? " + has_degraded" : "",
-        (state & PG_INCOMPLETE) ? "incomplete" : "",
+        (pg.state & PG_HAS_MISPLACED) ? " + has_misplaced" : "",
-        (state & PG_ACTIVE) ? "active" : "",
+        (pg.state & PG_HAS_UNCLEAN) ? " + has_unclean" : "",
-        (state & PG_STOPPING) ? "stopping" : "",
+        pg.total_count
        (state & PG_DEGRADED) ? " + degraded" : "",
        (state & PG_HAS_INCOMPLETE) ? " + has_incomplete" : "",
        (state & PG_HAS_DEGRADED) ? " + has_degraded" : "",
        (state & PG_HAS_MISPLACED) ? " + has_misplaced" : "",
        (state & PG_HAS_UNCLEAN) ? " + has_unclean" : "",
        (state & PG_HAS_INVALID) ? " + has_invalid" : "",
        (state & PG_LEFT_ON_DEAD) ? " + left_on_dead" : "",
        total_count
    );
    pg.state = pg.state | PG_ACTIVE;
 }
--- a/osd_peering_pg.h
+++ b/osd_peering_pg.h
@ -1,24 +1,43 @@
 // Copyright (c) Vitaliy Filippov, 2019+
 // License: VNPL-1.0 (see README.md for details)
 #include <map>
 #include <unordered_map>
 #include <vector>
 #include <algorithm>
 #include "cpp-btree/btree_map.h"
 #include "object_id.h"
 #include "osd_ops.h"
 #include "pg_states.h"
-#define PG_EPOCH_BITS 48
+#include "sparsepp/sparsepp/spp.h"
 // Placement group states
 // Exactly one of these:
 #define PG_OFFLINE (1<<0)
 #define PG_PEERING (1<<1)
 #define PG_INCOMPLETE (1<<2)
 #define PG_ACTIVE (1<<3)
 // Plus any of these:
 #define PG_DEGRADED (1<<4)
 #define PG_HAS_UNFOUND (1<<5)
 #define PG_HAS_DEGRADED (1<<6)
 #define PG_HAS_MISPLACED (1<<7)
 #define PG_HAS_UNCLEAN (1<<8)
 // FIXME: Safe default that doesn't depend on parity_block_size of pg_parity_size
 #define STRIPE_MASK ((uint64_t)4096 - 1)
 // OSD object states
 #define OBJ_CLEAN 0x01
 #define OBJ_MISPLACED 0x02
 #define OBJ_DEGRADED 0x03
 #define OBJ_INCOMPLETE 0x04
 #define OBJ_NEEDS_STABLE 0x10000
 #define OBJ_NEEDS_ROLLBACK 0x20000
 #define OBJ_OVERCOPIED 0x40000
 #define OBJ_BUGGY 0x80000
 struct pg_obj_loc_t
 {
    uint64_t role;
    osd_num_t osd_num;
-    bool outdated;
+    bool stable;
 };
 typedef std::vector<pg_obj_loc_t> pg_osd_set_t;
@ -45,10 +64,28 @@ struct osd_op_t;
 struct pg_peering_state_t
 {
    // osd_num -> list result
-    std::unordered_map<osd_num_t, osd_op_t*> list_ops;
+    spp::sparse_hash_map<osd_num_t, osd_op_t*> list_ops;
-    std::unordered_map<osd_num_t, pg_list_result_t> list_results;
+    spp::sparse_hash_map<osd_num_t, pg_list_result_t> list_results;
-    pool_id_t pool_id = 0;
+    int list_done = 0;
-    pg_num_t pg_num = 0;
+};
 struct pg_obj_state_check_t
 {
    int obj_start = 0, obj_end = 0, ver_start = 0, ver_end = 0;
    object_id oid = { 0 };
    uint64_t max_ver = 0;
    uint64_t target_ver = 0;
    uint64_t n_copies = 0, has_roles = 0, n_roles = 0, n_stable = 0, n_matched = 0;
    bool is_buggy = false, has_old_unstable = false;
    pg_osd_set_t osd_set;
 };
 struct obj_ver_role
 {
    object_id oid;
    uint64_t version;
    uint64_t osd_num;
    bool is_stable;
 };
 struct obj_piece_id_t
@ -57,67 +94,60 @@ struct obj_piece_id_t
    uint64_t osd_num;
 };
-struct flush_action_t
+struct obj_piece_ver_t
 {
    uint64_t max_ver = 0;
    uint64_t stable_ver = 0;
 };
 struct obj_stab_action_t
 {
    bool rollback = false, make_stable = false;
    uint64_t stable_to = 0, rollback_to = 0;
    bool submitted = false;
 };
 struct pg_flush_batch_t
 {
    std::map<osd_num_t, std::vector<obj_ver_id>> rollback_lists;
    std::map<osd_num_t, std::vector<obj_ver_id>> stable_lists;
    int flush_ops = 0, flush_done = 0;
    int flush_objects = 0;
 };
 struct pg_t
 {
-    int state = 0;
+    int state;
-    uint64_t scheme = 0;
+    uint64_t pg_cursize = 3, pg_size = 3, pg_minsize = 2;
-    uint64_t pg_cursize = 0, pg_size = 0, pg_minsize = 0;
+    pg_num_t pg_num;
    pool_id_t pool_id = 0;
    pg_num_t pg_num = 0;
    uint64_t clean_count = 0, total_count = 0;
    // epoch number - should increase with each non-clean activation of the PG
    uint64_t epoch = 0, reported_epoch = 0;
    // target history and all potential peers
    std::vector<std::vector<osd_num_t>> target_history;
    std::vector<osd_num_t> all_peers;
    bool history_changed = false;
    // peer list from the last peering event
    std::vector<osd_num_t> cur_peers;
    // target_set is the "correct" peer OSD set for this PG
    std::vector<osd_num_t> target_set;
    // cur_set is the current set of connected peer OSDs for this PG
    // cur_set = (role => osd_num or UINT64_MAX if missing). role numbers begin with zero
    std::vector<osd_num_t> cur_set;
    // same thing in state_dict-like format
    pg_osd_set_t cur_loc_set;
    // moved object map. by default, each object is considered to reside on the cur_set.
    // this map stores all objects that differ.
    // it may consume up to ~ (raw storage / object size) * 24 bytes in the worst case scenario
    // which is up to ~192 MB per 1 TB in the worst case scenario
    std::map<pg_osd_set_t, pg_osd_set_state_t> state_dict;
-    btree::btree_map<object_id, pg_osd_set_state_t*> incomplete_objects, misplaced_objects, degraded_objects;
+    spp::sparse_hash_map<object_id, pg_osd_set_state_t*> obj_states;
-    std::map<obj_piece_id_t, flush_action_t> flush_actions;
+    std::map<obj_piece_id_t, obj_stab_action_t> obj_stab_actions;
-    btree::btree_map<object_id, uint64_t> ver_override;
+    spp::sparse_hash_map<object_id, uint64_t> ver_override;
    pg_peering_state_t *peering_state = NULL;
    pg_flush_batch_t *flush_batch = NULL;
    int inflight = 0; // including write_queue
    std::multimap<object_id, osd_op_t*> write_queue;
-    void calc_object_states(int log_level);
+    void calc_object_states();
-    void print_state();
+    void remember_object(pg_obj_state_check_t &st, std::vector<obj_ver_role> &all);
 };
 inline bool operator < (const pg_obj_loc_t &a, const pg_obj_loc_t &b)
 {
-    return a.outdated < b.outdated ||
+    return a.role < b.role || a.role == b.role && a.osd_num < b.osd_num ||
-        a.outdated == b.outdated && a.role < b.role ||
+        a.role == b.role && a.osd_num == b.osd_num && a.stable < b.stable;
-        a.outdated == b.outdated && a.role == b.role && a.osd_num < b.osd_num;
+}
 inline bool operator < (const obj_ver_role & a, const obj_ver_role & b)
 {
    // ORDER BY inode ASC, stripe & ~STRIPE_MASK ASC, version DESC, osd_num ASC
    return a.oid.inode < b.oid.inode || a.oid.inode == b.oid.inode && (
        (a.oid.stripe & ~STRIPE_MASK) < (b.oid.stripe & ~STRIPE_MASK) ||
        (a.oid.stripe & ~STRIPE_MASK) == (b.oid.stripe & ~STRIPE_MASK) && (
            a.version > b.version || a.version == b.version && a.osd_num < b.osd_num
        )
    );
 }
 inline bool operator == (const obj_piece_id_t & a, const obj_piece_id_t & b)
@ -142,6 +172,7 @@ namespace std
                // Copy-pasted from spp::hash_combine()
                seed ^= (e.role + 0xc6a4a7935bd1e995 + (seed << 6) + (seed >> 2));
                seed ^= (e.osd_num + 0xc6a4a7935bd1e995 + (seed << 6) + (seed >> 2));
                seed ^= ((e.stable ? 1 : 0) + 0xc6a4a7935bd1e995 + (seed << 6) + (seed >> 2));
            }
            return seed;
        }
--- a/osd_peering_pg_test.cpp
+++ b/osd_peering_pg_test.cpp
@ -1,57 +0,0 @@
 // Copyright (c) Vitaliy Filippov, 2019+
 // License: VNPL-1.0 (see README.md for details)
 #define _LARGEFILE64_SOURCE
 #include "osd_peering_pg.h"
 #define STRIPE_SHIFT 12
 /**
 * TODO tests for object & pg state calculation.
 *
 * 1) pg=1,2,3. objects:
 *    v1=1s,2s,3s -> clean
 *    v1=1s,2s,3 v2=1s,2s,_ -> degraded + needs_rollback
 *    v1=1s,2s,_ -> degraded
 *    v1=1s,2s,3s v2=1,6,_ -> degraded + needs_stabilize
 *    v1=2s,1s,3s -> misplaced
 *    v1=4,5,6 -> misplaced + needs_stabilize
 *    v1=1s,2s,6s -> misplaced
 * 2) ...
 */
 int main(int argc, char *argv[])
 {
    pg_t pg = {
        .state = PG_PEERING,
        .pg_num = 1,
        .target_set = { 1, 2, 3 },
        .cur_set = { 1, 2, 3 },
        .peering_state = new pg_peering_state_t(),
    };
    for (uint64_t osd_num = 1; osd_num <= 3; osd_num++)
    {
        pg_list_result_t r = {
            .buf = (obj_ver_id*)malloc_or_die(sizeof(obj_ver_id) * 1024*1024*8),
            .total_count = 1024*1024*8,
            .stable_count = (uint64_t)(1024*1024*8 - (osd_num == 1 ? 10 : 0)),
        };
        for (uint64_t i = 0; i < r.total_count; i++)
        {
            r.buf[i] = {
                .oid = {
                    .inode = 1,
                    .stripe = (i << STRIPE_SHIFT) | (osd_num-1),
                },
                .version = (uint64_t)(osd_num == 1 && i >= r.total_count - 10 ? 2 : 1),
            };
        }
        pg.peering_state->list_results[osd_num] = r;
    }
    pg.calc_object_states(0);
    printf("deviation variants=%ld clean=%lu\n", pg.state_dict.size(), pg.clean_count);
    for (auto it: pg.state_dict)
    {
        printf("dev: state=%lx\n", it.second.state);
    }
    return 0;
 }
--- a/osd_primary.cpp
+++ b/osd_primary.cpp
--- a/osd_primary.h
+++ b/osd_primary.h
@ -1,41 +0,0 @@
 // Copyright (c) Vitaliy Filippov, 2019+
 // License: VNPL-1.0 (see README.md for details)
 #pragma once
 #include "osd.h"
 #include "osd_rmw.h"
 #define SUBMIT_READ 0
 #define SUBMIT_RMW_READ 1
 #define SUBMIT_WRITE 2
 struct unstable_osd_num_t
 {
    osd_num_t osd_num;
    int start, len;
 };
 struct osd_primary_op_data_t
 {
    int st = 0;
    pg_num_t pg_num;
    object_id oid;
    uint64_t target_ver;
    uint64_t fact_ver = 0;
    uint64_t scheme = 0;
    int n_subops = 0, done = 0, errors = 0, epipe = 0;
    int degraded = 0, pg_size, pg_minsize;
    osd_rmw_stripe_t *stripes;
    osd_op_t *subops = NULL;
    uint64_t *prev_set = NULL;
    pg_osd_set_state_t *object_state = NULL;
    // for sync. oops, requires freeing
    std::vector<unstable_osd_num_t> *unstable_write_osds = NULL;
    pool_pg_num_t *dirty_pgs = NULL;
    int dirty_pg_count = 0;
    osd_num_t *dirty_osds = NULL;
    int dirty_osd_count = 0;
    obj_ver_id *unstable_writes = NULL;
 };
--- a/osd_primary_subops.cpp
+++ b/osd_primary_subops.cpp
@ -1,575 +0,0 @@
 // Copyright (c) Vitaliy Filippov, 2019+
 // License: VNPL-1.0 (see README.md for details)
 #include "osd_primary.h"
 void osd_t::autosync()
 {
    // FIXME Autosync based on the number of unstable writes to prevent
    // "journal_sector_buffer_count is too low for this batch" errors
    if (immediate_commit != IMMEDIATE_ALL && !autosync_op)
    {
        autosync_op = new osd_op_t();
        autosync_op->op_type = OSD_OP_IN;
        autosync_op->req = {
            .sync = {
                .header = {
                    .magic = SECONDARY_OSD_OP_MAGIC,
                    .id = 1,
                    .opcode = OSD_OP_SYNC,
                },
            },
        };
        autosync_op->callback = [this](osd_op_t *op)
        {
            if (op->reply.hdr.retval < 0)
            {
                printf("Warning: automatic sync resulted in an error: %ld (%s)\n", -op->reply.hdr.retval, strerror(-op->reply.hdr.retval));
            }
            delete autosync_op;
            autosync_op = NULL;
        };
        exec_op(autosync_op);
    }
 }
 void osd_t::finish_op(osd_op_t *cur_op, int retval)
 {
    inflight_ops--;
    if (cur_op->op_data)
    {
        if (cur_op->op_data->pg_num > 0)
        {
            auto & pg = pgs[{ .pool_id = INODE_POOL(cur_op->op_data->oid.inode), .pg_num = cur_op->op_data->pg_num }];
            pg.inflight--;
            assert(pg.inflight >= 0);
            if ((pg.state & PG_STOPPING) && pg.inflight == 0 && !pg.flush_batch)
            {
                finish_stop_pg(pg);
            }
        }
        assert(!cur_op->op_data->subops);
        assert(!cur_op->op_data->unstable_write_osds);
        assert(!cur_op->op_data->unstable_writes);
        assert(!cur_op->op_data->dirty_pgs);
        free(cur_op->op_data);
        cur_op->op_data = NULL;
    }
    if (!cur_op->peer_fd)
    {
        // Copy lambda to be unaffected by `delete op`
        std::function<void(osd_op_t*)>(cur_op->callback)(cur_op);
    }
    else
    {
        // FIXME add separate magic number
        auto cl_it = c_cli.clients.find(cur_op->peer_fd);
        if (cl_it != c_cli.clients.end())
        {
            cur_op->reply.hdr.magic = SECONDARY_OSD_REPLY_MAGIC;
            cur_op->reply.hdr.id = cur_op->req.hdr.id;
            cur_op->reply.hdr.opcode = cur_op->req.hdr.opcode;
            cur_op->reply.hdr.retval = retval;
            c_cli.outbox_push(cur_op);
        }
        else
        {
            delete cur_op;
        }
    }
 }
 void osd_t::submit_primary_subops(int submit_type, uint64_t op_version, int pg_size, const uint64_t* osd_set, osd_op_t *cur_op)
 {
    bool wr = submit_type == SUBMIT_WRITE;
    osd_primary_op_data_t *op_data = cur_op->op_data;
    osd_rmw_stripe_t *stripes = op_data->stripes;
    bool rep = op_data->scheme == POOL_SCHEME_REPLICATED;
    // Allocate subops
    int n_subops = 0, zero_read = -1;
    for (int role = 0; role < pg_size; role++)
    {
        if (osd_set[role] == this->osd_num || osd_set[role] != 0 && zero_read == -1)
        {
            zero_read = role;
        }
        if (osd_set[role] != 0 && (wr || !rep && stripes[role].read_end != 0))
        {
            n_subops++;
        }
    }
    if (!n_subops && (submit_type == SUBMIT_RMW_READ || rep))
    {
        n_subops = 1;
    }
    else
    {
        zero_read = -1;
    }
    osd_op_t *subops = new osd_op_t[n_subops];
    op_data->fact_ver = 0;
    op_data->done = op_data->errors = 0;
    op_data->n_subops = n_subops;
    op_data->subops = subops;
    int i = 0;
    for (int role = 0; role < pg_size; role++)
    {
        // We always submit zero-length writes to all replicas, even if the stripe is not modified
        if (!(wr || !rep && stripes[role].read_end != 0 || zero_read == role))
        {
            continue;
        }
        osd_num_t role_osd_num = osd_set[role];
        if (role_osd_num != 0)
        {
            int stripe_num = rep ? 0 : role;
            if (role_osd_num == this->osd_num)
            {
                clock_gettime(CLOCK_REALTIME, &subops[i].tv_begin);
                subops[i].op_type = (uint64_t)cur_op;
                subops[i].bs_op = new blockstore_op_t({
                    .opcode = (uint64_t)(wr ? (rep ? BS_OP_WRITE_STABLE : BS_OP_WRITE) : BS_OP_READ),
                    .callback = [subop = &subops[i], this](blockstore_op_t *bs_subop)
                    {
                        handle_primary_bs_subop(subop);
                    },
                    .oid = {
                        .inode = op_data->oid.inode,
                        .stripe = op_data->oid.stripe | stripe_num,
                    },
                    .version = op_version,
                    .offset = wr ? stripes[stripe_num].write_start : stripes[stripe_num].read_start,
                    .len = wr ? stripes[stripe_num].write_end - stripes[stripe_num].write_start : stripes[stripe_num].read_end - stripes[stripe_num].read_start,
                    .buf = wr ? stripes[stripe_num].write_buf : stripes[stripe_num].read_buf,
                });
 #ifdef OSD_DEBUG
                printf(
                    "Submit %s to local: %lx:%lx v%lu %u-%u\n", wr ? "write" : "read",
                    op_data->oid.inode, op_data->oid.stripe | stripe_num, op_version,
                    subops[i].bs_op->offset, subops[i].bs_op->len
                );
 #endif
                bs->enqueue_op(subops[i].bs_op);
            }
            else
            {
                subops[i].op_type = OSD_OP_OUT;
                subops[i].peer_fd = c_cli.osd_peer_fds.at(role_osd_num);
                subops[i].req.sec_rw = {
                    .header = {
                        .magic = SECONDARY_OSD_OP_MAGIC,
                        .id = c_cli.next_subop_id++,
                        .opcode = (uint64_t)(wr ? (rep ? OSD_OP_SEC_WRITE_STABLE : OSD_OP_SEC_WRITE) : OSD_OP_SEC_READ),
                    },
                    .oid = {
                        .inode = op_data->oid.inode,
                        .stripe = op_data->oid.stripe | stripe_num,
                    },
                    .version = op_version,
                    .offset = wr ? stripes[stripe_num].write_start : stripes[stripe_num].read_start,
                    .len = wr ? stripes[stripe_num].write_end - stripes[stripe_num].write_start : stripes[stripe_num].read_end - stripes[stripe_num].read_start,
                };
 #ifdef OSD_DEBUG
                printf(
                    "Submit %s to osd %lu: %lx:%lx v%lu %u-%u\n", wr ? "write" : "read", role_osd_num,
                    op_data->oid.inode, op_data->oid.stripe | stripe_num, op_version,
                    subops[i].req.sec_rw.offset, subops[i].req.sec_rw.len
                );
 #endif
                if (wr)
                {
                    if (stripes[stripe_num].write_end > stripes[stripe_num].write_start)
                    {
                        subops[i].iov.push_back(stripes[stripe_num].write_buf, stripes[stripe_num].write_end - stripes[stripe_num].write_start);
                    }
                }
                else
                {
                    if (stripes[stripe_num].read_end > stripes[stripe_num].read_start)
                    {
                        subops[i].iov.push_back(stripes[stripe_num].read_buf, stripes[stripe_num].read_end - stripes[stripe_num].read_start);
                    }
                }
                subops[i].callback = [cur_op, this](osd_op_t *subop)
                {
                    int fail_fd = subop->req.hdr.opcode == OSD_OP_SEC_WRITE &&
                        subop->reply.hdr.retval != subop->req.sec_rw.len ? subop->peer_fd : -1;
                    handle_primary_subop(subop, cur_op);
                    if (fail_fd >= 0)
                    {
                        // write operation failed, drop the connection
                        c_cli.stop_client(fail_fd);
                    }
                };
                c_cli.outbox_push(&subops[i]);
            }
            i++;
        }
    }
 }
 static uint64_t bs_op_to_osd_op[] = {
    0,
    OSD_OP_SEC_READ,            // BS_OP_READ = 1
    OSD_OP_SEC_WRITE,           // BS_OP_WRITE = 2
    OSD_OP_SEC_WRITE_STABLE,    // BS_OP_WRITE_STABLE = 3
    OSD_OP_SEC_SYNC,            // BS_OP_SYNC = 4
    OSD_OP_SEC_STABILIZE,       // BS_OP_STABLE = 5
    OSD_OP_SEC_DELETE,          // BS_OP_DELETE = 6
    OSD_OP_SEC_LIST,            // BS_OP_LIST = 7
    OSD_OP_SEC_ROLLBACK,        // BS_OP_ROLLBACK = 8
    OSD_OP_TEST_SYNC_STAB_ALL,  // BS_OP_SYNC_STAB_ALL = 9
 };
 void osd_t::handle_primary_bs_subop(osd_op_t *subop)
 {
    osd_op_t *cur_op = (osd_op_t*)subop->op_type;
    blockstore_op_t *bs_op = subop->bs_op;
    int expected = bs_op->opcode == BS_OP_READ || bs_op->opcode == BS_OP_WRITE
        || bs_op->opcode == BS_OP_WRITE_STABLE ? bs_op->len : 0;
    if (bs_op->retval != expected && bs_op->opcode != BS_OP_READ)
    {
        // die
        throw std::runtime_error(
            "local blockstore modification failed (opcode = "+std::to_string(bs_op->opcode)+
            " retval = "+std::to_string(bs_op->retval)+")"
        );
    }
    add_bs_subop_stats(subop);
    subop->req.hdr.opcode = bs_op_to_osd_op[bs_op->opcode];
    subop->reply.hdr.retval = bs_op->retval;
    if (bs_op->opcode == BS_OP_READ || bs_op->opcode == BS_OP_WRITE || bs_op->opcode == BS_OP_WRITE_STABLE)
    {
        subop->req.sec_rw.len = bs_op->len;
        subop->reply.sec_rw.version = bs_op->version;
    }
    delete bs_op;
    subop->bs_op = NULL;
    handle_primary_subop(subop, cur_op);
 }
 void osd_t::add_bs_subop_stats(osd_op_t *subop)
 {
    // Include local blockstore ops in statistics
    uint64_t opcode = bs_op_to_osd_op[subop->bs_op->opcode];
    timespec tv_end;
    clock_gettime(CLOCK_REALTIME, &tv_end);
    c_cli.stats.op_stat_count[opcode]++;
    if (!c_cli.stats.op_stat_count[opcode])
    {
        c_cli.stats.op_stat_count[opcode] = 1;
        c_cli.stats.op_stat_sum[opcode] = 0;
        c_cli.stats.op_stat_bytes[opcode] = 0;
    }
    c_cli.stats.op_stat_sum[opcode] += (
        (tv_end.tv_sec - subop->tv_begin.tv_sec)*1000000 +
        (tv_end.tv_nsec - subop->tv_begin.tv_nsec)/1000
    );
    if (opcode == OSD_OP_SEC_READ || opcode == OSD_OP_SEC_WRITE)
    {
        c_cli.stats.op_stat_bytes[opcode] += subop->bs_op->len;
    }
 }
 void osd_t::handle_primary_subop(osd_op_t *subop, osd_op_t *cur_op)
 {
    uint64_t opcode = subop->req.hdr.opcode;
    int retval = subop->reply.hdr.retval;
    int expected = opcode == OSD_OP_SEC_READ || opcode == OSD_OP_SEC_WRITE
        || opcode == OSD_OP_SEC_WRITE_STABLE ? subop->req.sec_rw.len : 0;
    osd_primary_op_data_t *op_data = cur_op->op_data;
    if (retval != expected)
    {
        printf("%s subop failed: retval = %d (expected %d)\n", osd_op_names[opcode], retval, expected);
        if (retval == -EPIPE)
        {
            op_data->epipe++;
        }
        op_data->errors++;
    }
    else
    {
        op_data->done++;
        if (opcode == OSD_OP_SEC_READ || opcode == OSD_OP_SEC_WRITE || opcode == OSD_OP_SEC_WRITE_STABLE)
        {
            uint64_t version = subop->reply.sec_rw.version;
 #ifdef OSD_DEBUG
            uint64_t peer_osd = c_cli.clients.find(subop->peer_fd) != c_cli.clients.end()
                ? c_cli.clients[subop->peer_fd].osd_num : osd_num;
            printf("subop %lu from osd %lu: version = %lu\n", opcode, peer_osd, version);
 #endif
            if (op_data->fact_ver != 0 && op_data->fact_ver != version)
            {
                throw std::runtime_error(
                    "different fact_versions returned from "+std::string(osd_op_names[opcode])+
                    " subops: "+std::to_string(version)+" vs "+std::to_string(op_data->fact_ver)
                );
            }
            op_data->fact_ver = version;
        }
    }
    if ((op_data->errors + op_data->done) >= op_data->n_subops)
    {
        delete[] op_data->subops;
        op_data->subops = NULL;
        op_data->st++;
        if (cur_op->req.hdr.opcode == OSD_OP_READ)
        {
            continue_primary_read(cur_op);
        }
        else if (cur_op->req.hdr.opcode == OSD_OP_WRITE)
        {
            continue_primary_write(cur_op);
        }
        else if (cur_op->req.hdr.opcode == OSD_OP_SYNC)
        {
            continue_primary_sync(cur_op);
        }
        else if (cur_op->req.hdr.opcode == OSD_OP_DELETE)
        {
            continue_primary_del(cur_op);
        }
        else
        {
            throw std::runtime_error("BUG: unknown opcode");
        }
    }
 }
 void osd_t::cancel_primary_write(osd_op_t *cur_op)
 {
    if (cur_op->op_data && cur_op->op_data->subops)
    {
        // Primary-write operation is waiting for subops, subops
        // are sent to peer OSDs, so we can't just throw them away.
        // Mark them with an extra EPIPE.
        cur_op->op_data->errors++;
        cur_op->op_data->epipe++;
        cur_op->op_data->done--; // Caution: `done` must be signed because may become -1 here
    }
    else
    {
        finish_op(cur_op, -EPIPE);
    }
 }
 static bool contains_osd(osd_num_t *osd_set, uint64_t size, osd_num_t osd_num)
 {
    for (uint64_t i = 0; i < size; i++)
    {
        if (osd_set[i] == osd_num)
        {
            return true;
        }
    }
    return false;
 }
 void osd_t::submit_primary_del_subops(osd_op_t *cur_op, osd_num_t *cur_set, uint64_t set_size, pg_osd_set_t & loc_set)
 {
    osd_primary_op_data_t *op_data = cur_op->op_data;
    bool rep = op_data->scheme == POOL_SCHEME_REPLICATED;
    int extra_chunks = 0;
    // ordered comparison for EC/XOR, unordered for replicated pools
    for (auto & chunk: loc_set)
    {
        if (!cur_set || (rep ? !contains_osd(cur_set, set_size, chunk.osd_num) : chunk.osd_num != cur_set[chunk.role]))
        {
            extra_chunks++;
        }
    }
    op_data->n_subops = extra_chunks;
    op_data->done = op_data->errors = 0;
    if (!extra_chunks)
    {
        return;
    }
    osd_op_t *subops = new osd_op_t[extra_chunks];
    op_data->subops = subops;
    int i = 0;
    for (auto & chunk: loc_set)
    {
        if (!cur_set || (rep ? !contains_osd(cur_set, set_size, chunk.osd_num) : chunk.osd_num != cur_set[chunk.role]))
        {
            int stripe_num = op_data->scheme == POOL_SCHEME_REPLICATED ? 0 : chunk.role;
            if (chunk.osd_num == this->osd_num)
            {
                clock_gettime(CLOCK_REALTIME, &subops[i].tv_begin);
                subops[i].op_type = (uint64_t)cur_op;
                subops[i].bs_op = new blockstore_op_t({
                    .opcode = BS_OP_DELETE,
                    .callback = [subop = &subops[i], this](blockstore_op_t *bs_subop)
                    {
                        handle_primary_bs_subop(subop);
                    },
                    .oid = {
                        .inode = op_data->oid.inode,
                        .stripe = op_data->oid.stripe | stripe_num,
                    },
                    // Same version as write
                    .version = op_data->fact_ver,
                });
                bs->enqueue_op(subops[i].bs_op);
            }
            else
            {
                subops[i].op_type = OSD_OP_OUT;
                subops[i].peer_fd = c_cli.osd_peer_fds.at(chunk.osd_num);
                subops[i].req.sec_del = {
                    .header = {
                        .magic = SECONDARY_OSD_OP_MAGIC,
                        .id = c_cli.next_subop_id++,
                        .opcode = OSD_OP_SEC_DELETE,
                    },
                    .oid = {
                        .inode = op_data->oid.inode,
                        .stripe = op_data->oid.stripe | stripe_num,
                    },
                    // Same version as write
                    .version = op_data->fact_ver,
                };
                subops[i].callback = [cur_op, this](osd_op_t *subop)
                {
                    int fail_fd = subop->reply.hdr.retval != 0 ? subop->peer_fd : -1;
                    handle_primary_subop(subop, cur_op);
                    if (fail_fd >= 0)
                    {
                        // delete operation failed, drop the connection
                        c_cli.stop_client(fail_fd);
                    }
                };
                c_cli.outbox_push(&subops[i]);
            }
            i++;
        }
    }
 }
 void osd_t::submit_primary_sync_subops(osd_op_t *cur_op)
 {
    osd_primary_op_data_t *op_data = cur_op->op_data;
    int n_osds = op_data->dirty_osd_count;
    osd_op_t *subops = new osd_op_t[n_osds];
    op_data->done = op_data->errors = 0;
    op_data->n_subops = n_osds;
    op_data->subops = subops;
    for (int i = 0; i < n_osds; i++)
    {
        osd_num_t sync_osd = op_data->dirty_osds[i];
        if (sync_osd == this->osd_num)
        {
            clock_gettime(CLOCK_REALTIME, &subops[i].tv_begin);
            subops[i].op_type = (uint64_t)cur_op;
            subops[i].bs_op = new blockstore_op_t({
                .opcode = BS_OP_SYNC,
                .callback = [subop = &subops[i], this](blockstore_op_t *bs_subop)
                {
                    handle_primary_bs_subop(subop);
                },
            });
            bs->enqueue_op(subops[i].bs_op);
        }
        else
        {
            subops[i].op_type = OSD_OP_OUT;
            subops[i].peer_fd = c_cli.osd_peer_fds.at(sync_osd);
            subops[i].req.sec_sync = {
                .header = {
                    .magic = SECONDARY_OSD_OP_MAGIC,
                    .id = c_cli.next_subop_id++,
                    .opcode = OSD_OP_SEC_SYNC,
                },
            };
            subops[i].callback = [cur_op, this](osd_op_t *subop)
            {
                int fail_fd = subop->reply.hdr.retval != 0 ? subop->peer_fd : -1;
                handle_primary_subop(subop, cur_op);
                if (fail_fd >= 0)
                {
                    // sync operation failed, drop the connection
                    c_cli.stop_client(fail_fd);
                }
            };
            c_cli.outbox_push(&subops[i]);
        }
    }
 }
 void osd_t::submit_primary_stab_subops(osd_op_t *cur_op)
 {
    osd_primary_op_data_t *op_data = cur_op->op_data;
    int n_osds = op_data->unstable_write_osds->size();
    osd_op_t *subops = new osd_op_t[n_osds];
    op_data->done = op_data->errors = 0;
    op_data->n_subops = n_osds;
    op_data->subops = subops;
    for (int i = 0; i < n_osds; i++)
    {
        auto & stab_osd = (*(op_data->unstable_write_osds))[i];
        if (stab_osd.osd_num == this->osd_num)
        {
            clock_gettime(CLOCK_REALTIME, &subops[i].tv_begin);
            subops[i].op_type = (uint64_t)cur_op;
            subops[i].bs_op = new blockstore_op_t({
                .opcode = BS_OP_STABLE,
                .callback = [subop = &subops[i], this](blockstore_op_t *bs_subop)
                {
                    handle_primary_bs_subop(subop);
                },
                .len = (uint32_t)stab_osd.len,
                .buf = (void*)(op_data->unstable_writes + stab_osd.start),
            });
            bs->enqueue_op(subops[i].bs_op);
        }
        else
        {
            subops[i].op_type = OSD_OP_OUT;
            subops[i].peer_fd = c_cli.osd_peer_fds.at(stab_osd.osd_num);
            subops[i].req.sec_stab = {
                .header = {
                    .magic = SECONDARY_OSD_OP_MAGIC,
                    .id = c_cli.next_subop_id++,
                    .opcode = OSD_OP_SEC_STABILIZE,
                },
                .len = (uint64_t)(stab_osd.len * sizeof(obj_ver_id)),
            };
            subops[i].iov.push_back(op_data->unstable_writes + stab_osd.start, stab_osd.len * sizeof(obj_ver_id));
            subops[i].callback = [cur_op, this](osd_op_t *subop)
            {
                int fail_fd = subop->reply.hdr.retval != 0 ? subop->peer_fd : -1;
                handle_primary_subop(subop, cur_op);
                if (fail_fd >= 0)
                {
                    // sync operation failed, drop the connection
                    c_cli.stop_client(fail_fd);
                }
            };
            c_cli.outbox_push(&subops[i]);
        }
    }
 }
 void osd_t::pg_cancel_write_queue(pg_t & pg, osd_op_t *first_op, object_id oid, int retval)
 {
    auto st_it = pg.write_queue.find(oid), it = st_it;
    finish_op(first_op, retval);
    if (it != pg.write_queue.end() && it->second == first_op)
    {
        it++;
    }
    else
    {
        // Write queue doesn't match the first operation.
        // first_op is a leftover operation from the previous peering of the same PG.
        return;
    }
    while (it != pg.write_queue.end() && it->first == oid)
    {
        finish_op(it->second, retval);
        it++;
    }
    if (st_it != it)
    {
        pg.write_queue.erase(st_it, it);
    }
 }
--- a/osd_receive.cpp
+++ b/osd_receive.cpp
@ -0,0 +1,206 @@
 #include "osd.h"
 void osd_t::read_requests()
 {
    for (int i = 0; i < read_ready_clients.size(); i++)
    {
        int peer_fd = read_ready_clients[i];
        auto & cl = clients[peer_fd];
        io_uring_sqe* sqe = ringloop->get_sqe();
        if (!sqe)
        {
            read_ready_clients.erase(read_ready_clients.begin(), read_ready_clients.begin() + i);
            return;
        }
        ring_data_t* data = ((ring_data_t*)sqe->user_data);
        if (!cl.read_buf)
        {
            // no reads in progress
            // so this is either a new command or a reply to a previously sent command
            if (!cl.read_op)
            {
                cl.read_op = new osd_op_t;
                cl.read_op->peer_fd = peer_fd;
            }
            cl.read_op->op_type = OSD_OP_IN;
            cl.read_buf = &cl.read_op->req.buf;
            cl.read_remaining = OSD_PACKET_SIZE;
            cl.read_state = CL_READ_OP;
        }
        cl.read_iov.iov_base = cl.read_buf;
        cl.read_iov.iov_len = cl.read_remaining;
        cl.read_msg.msg_iov = &cl.read_iov;
        cl.read_msg.msg_iovlen = 1;
        data->callback = [this, peer_fd](ring_data_t *data) { handle_read(data, peer_fd); };
        my_uring_prep_recvmsg(sqe, cl.peer_fd_index, &cl.read_msg, 0);
        sqe->flags |= IOSQE_FIXED_FILE;
    }
    read_ready_clients.clear();
 }
 void osd_t::handle_read(ring_data_t *data, int peer_fd)
 {
    int res = data->res;
    auto cl_it = clients.find(peer_fd);
    if (cl_it != clients.end())
    {
        auto & cl = cl_it->second;
        if (res == -EAGAIN)
        {
            cl.read_ready--;
            if (cl.read_ready > 0)
                read_ready_clients.push_back(peer_fd);
            return;
        }
        else if (res < 0)
        {
            // this is a client socket, so don't panic. just disconnect it
            printf("Client %d socket read error: %d (%s). Disconnecting client\n", peer_fd, -res, strerror(-res));
            stop_client(peer_fd);
            return;
        }
        read_ready_clients.push_back(peer_fd);
        if (res > 0)
        {
            cl.read_remaining -= res;
            cl.read_buf += res;
            if (cl.read_remaining <= 0)
            {
                cl.read_buf = NULL;
                if (cl.read_state == CL_READ_OP)
                {
                    if (cl.read_op->req.hdr.magic == SECONDARY_OSD_REPLY_MAGIC)
                    {
                        handle_reply_hdr(&cl);
                    }
                    else
                    {
                        handle_op_hdr(&cl);
                    }
                }
                else if (cl.read_state == CL_READ_DATA)
                {
                    // Operation is ready
                    exec_op(cl.read_op);
                    cl.read_op = NULL;
                    cl.read_state = 0;
                }
                else if (cl.read_state == CL_READ_REPLY_DATA)
                {
                    // Reply is ready
                    auto req_it = cl.sent_ops.find(cl.read_reply_id);
                    osd_op_t *request = req_it->second;
                    cl.sent_ops.erase(req_it);
                    cl.read_reply_id = 0;
                    cl.read_state = 0;
                    // Measure subop latency
                    timespec tv_end;
                    clock_gettime(CLOCK_REALTIME, &tv_end);
                    subop_stat_count[request->req.hdr.opcode]++;
                    subop_stat_sum[request->req.hdr.opcode] += (
                        (tv_end.tv_sec - request->tv_begin.tv_sec)*1000000 +
                        (tv_end.tv_nsec - request->tv_begin.tv_nsec)/1000
                    );
                    request->callback(request);
                }
            }
        }
    }
 }
 void osd_t::handle_op_hdr(osd_client_t *cl)
 {
    osd_op_t *cur_op = cl->read_op;
    if (cur_op->req.hdr.opcode == OSD_OP_SECONDARY_READ)
    {
        if (cur_op->req.sec_rw.len > 0)
            cur_op->buf = memalign(512, cur_op->req.sec_rw.len);
        cl->read_remaining = 0;
    }
    else if (cur_op->req.hdr.opcode == OSD_OP_SECONDARY_WRITE)
    {
        if (cur_op->req.sec_rw.len > 0)
            cur_op->buf = memalign(512, cur_op->req.sec_rw.len);
        cl->read_remaining = cur_op->req.sec_rw.len;
    }
    else if (cur_op->req.hdr.opcode == OSD_OP_SECONDARY_STABILIZE ||
        cur_op->req.hdr.opcode == OSD_OP_SECONDARY_ROLLBACK)
    {
        if (cur_op->req.sec_stab.len > 0)
            cur_op->buf = memalign(512, cur_op->req.sec_stab.len);
        cl->read_remaining = cur_op->req.sec_stab.len;
    }
    else if (cur_op->req.hdr.opcode == OSD_OP_READ)
    {
        if (cur_op->req.rw.len > 0)
            cur_op->buf = memalign(512, cur_op->req.rw.len);
        cl->read_remaining = 0;
    }
    else if (cur_op->req.hdr.opcode == OSD_OP_WRITE)
    {
        if (cur_op->req.rw.len > 0)
            cur_op->buf = memalign(512, cur_op->req.rw.len);
        cl->read_remaining = cur_op->req.rw.len;
    }
    if (cl->read_remaining > 0)
    {
        // Read data
        cl->read_buf = cur_op->buf;
        cl->read_state = CL_READ_DATA;
    }
    else
    {
        // Operation is ready
        cl->read_op = NULL;
        cl->read_state = 0;
        exec_op(cur_op);
    }
 }
 void osd_t::handle_reply_hdr(osd_client_t *cl)
 {
    osd_op_t *cur_op = cl->read_op;
    auto req_it = cl->sent_ops.find(cur_op->req.hdr.id);
    if (req_it == cl->sent_ops.end())
    {
        // Command out of sync. Drop connection
        printf("Client %d command out of sync: id %lu\n", cl->peer_fd, cur_op->req.hdr.id);
        stop_client(cl->peer_fd);
        return;
    }
    osd_op_t *op = req_it->second;
    memcpy(op->reply.buf, cur_op->req.buf, OSD_PACKET_SIZE);
    if (op->reply.hdr.opcode == OSD_OP_SECONDARY_READ &&
        op->reply.hdr.retval > 0)
    {
        // Read data. In this case we assume that the buffer is preallocated by the caller (!)
        assert(op->buf);
        cl->read_state = CL_READ_REPLY_DATA;
        cl->read_reply_id = op->req.hdr.id;
        cl->read_buf = op->buf;
        cl->read_remaining = op->reply.hdr.retval;
    }
    else if (op->reply.hdr.opcode == OSD_OP_SECONDARY_LIST &&
        op->reply.hdr.retval > 0)
    {
        op->buf = memalign(512, sizeof(obj_ver_id) * op->reply.hdr.retval);
        cl->read_state = CL_READ_REPLY_DATA;
        cl->read_reply_id = op->req.hdr.id;
        cl->read_buf = op->buf;
        cl->read_remaining = sizeof(obj_ver_id) * op->reply.hdr.retval;
    }
    else
    {
        cl->read_state = 0;
        cl->sent_ops.erase(req_it);
        // Measure subop latency
        timespec tv_end;
        clock_gettime(CLOCK_REALTIME, &tv_end);
        subop_stat_count[op->req.hdr.opcode]++;
        subop_stat_sum[op->req.hdr.opcode] += (
            (tv_end.tv_sec - op->tv_begin.tv_sec)*1000000 +
            (tv_end.tv_nsec - op->tv_begin.tv_nsec)/1000
        );
        op->callback(op);
    }
 }
--- a/osd_rmw.cpp
+++ b/osd_rmw.cpp
@ -1,11 +1,7 @@
-// Copyright (c) Vitaliy Filippov, 2019+
+#include <malloc.h>
 // License: VNPL-1.0 (see README.md for details)
 #include <string.h>
 #include <assert.h>
 #include "xor.h"
 #include "osd_rmw.h"
 #include "malloc_or_die.h"
 static inline void extend_read(uint32_t start, uint32_t end, osd_rmw_stripe_t & stripe)
 {
@ -59,11 +55,6 @@ static inline void cover_read(uint32_t start, uint32_t end, osd_rmw_stripe_t & s
 void split_stripes(uint64_t pg_minsize, uint32_t bs_block_size, uint32_t start, uint32_t end, osd_rmw_stripe_t *stripes)
 {
    if (end == 0)
    {
        // Zero length request - offset doesn't matter
        return;
    }
    end = start+end;
    for (int role = 0; role < pg_minsize; role++)
    {
@ -75,7 +66,7 @@ void split_stripes(uint64_t pg_minsize, uint32_t bs_block_size, uint32_t start,
    }
 }
-void reconstruct_stripe_xor(osd_rmw_stripe_t *stripes, int pg_size, int role)
+void reconstruct_stripe(osd_rmw_stripe_t *stripes, int pg_size, int role)
 {
    int prev = -2;
    for (int other = 0; other < pg_size; other++)
@ -88,21 +79,18 @@ void reconstruct_stripe_xor(osd_rmw_stripe_t *stripes, int pg_size, int role)
            }
            else if (prev >= 0)
            {
                assert(stripes[role].read_start >= stripes[prev].read_start &&
                    stripes[role].read_start >= stripes[other].read_start);
                memxor(
-                    stripes[prev].read_buf + (stripes[role].read_start - stripes[prev].read_start),
+                    stripes[prev].read_buf + (stripes[prev].read_start - stripes[role].read_start),
-                    stripes[other].read_buf + (stripes[role].read_start - stripes[other].read_start),
+                    stripes[other].read_buf + (stripes[other].read_start - stripes[other].read_start),
                    stripes[role].read_buf, stripes[role].read_end - stripes[role].read_start
                );
                prev = -1;
            }
            else
            {
                assert(stripes[role].read_start >= stripes[other].read_start);
                memxor(
                    stripes[role].read_buf,
-                    stripes[other].read_buf + (stripes[role].read_start - stripes[other].read_start),
+                    stripes[other].read_buf + (stripes[other].read_start - stripes[role].read_start),
                    stripes[role].read_buf, stripes[role].read_end - stripes[role].read_start
                );
            }
@ -155,7 +143,7 @@ void* alloc_read_buffer(osd_rmw_stripe_t *stripes, int read_pg_size, uint64_t ad
        }
    }
    // Allocate buffer
-    void *buf = memalign_or_die(MEM_ALIGNMENT, buf_size);
+    void *buf = memalign(MEM_ALIGNMENT, buf_size);
    uint64_t buf_pos = add_size;
    for (int role = 0; role < read_pg_size; role++)
    {
@ -168,11 +156,10 @@ void* alloc_read_buffer(osd_rmw_stripe_t *stripes, int read_pg_size, uint64_t ad
    return buf;
 }
-void* calc_rmw(void *request_buf, osd_rmw_stripe_t *stripes, uint64_t *read_osd_set,
+void* calc_rmw_reads(void *write_buf, osd_rmw_stripe_t *stripes, uint64_t *osd_set, uint64_t pg_size, uint64_t pg_minsize, uint64_t pg_cursize)
    uint64_t pg_size, uint64_t pg_minsize, uint64_t pg_cursize, uint64_t *write_osd_set, uint64_t chunk_size)
 {
    // Generic parity modification (read-modify-write) algorithm
-    // Read -> Reconstruct missing chunks -> Calc parity chunks -> Write
+    // Reconstruct -> Read -> Calc parity -> Write
    // Now we always read continuous ranges. This means that an update of the beginning
    // of one data stripe and the end of another will lead to a read of full paired stripes.
    // FIXME: (Maybe) read small individual ranges in that case instead.
@ -187,89 +174,64 @@ void* calc_rmw(void *request_buf, osd_rmw_stripe_t *stripes, uint64_t *read_osd_
            stripes[role].write_end = stripes[role].req_end;
        }
    }
-    int write_parity = 0;
+    for (int role = 0; role < pg_minsize; role++)
    {
        cover_read(start, end, stripes[role]);
    }
    int has_parity = 0;
    for (int role = pg_minsize; role < pg_size; role++)
    {
-        if (write_osd_set[role] != 0)
+        if (osd_set[role] != 0)
        {
-            write_parity = 1;
+            has_parity++;
            stripes[role].write_start = start;
            stripes[role].write_end = end;
        }
-    }
+        else
-    if (write_parity)
+            stripes[role].missing = true;
    {
        for (int role = 0; role < pg_minsize; role++)
        {
            cover_read(start, end, stripes[role]);
        }
    }
    if (write_osd_set != read_osd_set)
    {
        pg_cursize = 0;
        // Object is degraded/misplaced and will be moved to <write_osd_set>
        for (int role = 0; role < pg_size; role++)
        {
            if (write_osd_set[role] != read_osd_set[role] && write_osd_set[role] != 0)
            {
                // We need to get data for any moved / recovered chunk
                // And we need a continuous write buffer so we'll only optimize
                // for the case when the whole chunk is ovewritten in the request
                if (stripes[role].req_start != 0 ||
                    stripes[role].req_end != chunk_size)
                {
                    stripes[role].read_start = 0;
                    stripes[role].read_end = chunk_size;
                    // Warning: We don't modify write_start/write_end here, we do it in calc_rmw_parity()
                }
            }
            if (read_osd_set[role] != 0)
            {
                pg_cursize++;
            }
        }
    }
    if (pg_cursize < pg_size)
    {
-        // Some stripe(s) are missing, so we need to read parity
+        if (has_parity == 0)
        for (int role = 0; role < pg_size; role++)
        {
-            if (read_osd_set[role] == 0)
+            // Parity is missing, we don't need to read anything
            for (int role = 0; role < pg_minsize; role++)
            {
-                stripes[role].missing = true;
+                stripes[role].read_end = 0;
-                if (stripes[role].read_end != 0)
+            }
        }
        else
        {
            // Other stripe(s) are missing
            for (int role = 0; role < pg_minsize; role++)
            {
                if (osd_set[role] == 0 && stripes[role].read_end != 0)
                {
-                    int found = 0;
+                    stripes[role].missing = true;
-                    for (int r2 = 0; r2 < pg_size && found < pg_minsize; r2++)
+                    for (int r2 = 0; r2 < pg_size; r2++)
                    {
-                        // Read the non-covered range of <role> from at least <minsize> other stripes to reconstruct it
+                        // Read the non-covered range of <role> from all other stripes to reconstruct it
-                        if (read_osd_set[r2] != 0)
+                        if (r2 != role && osd_set[r2] != 0)
                        {
                            extend_read(stripes[role].read_start, stripes[role].read_end, stripes[r2]);
                            found++;
                        }
                    }
                    if (found < pg_minsize)
                    {
                        // FIXME Object is incomplete - refuse partial overwrite
                        assert(0);
                    }
                }
            }
        }
    }
    // Allocate read buffers
-    void *rmw_buf = alloc_read_buffer(stripes, pg_size, (write_parity ? pg_size-pg_minsize : 0) * (end - start));
+    void *rmw_buf = alloc_read_buffer(stripes, pg_size, has_parity * (end - start));
-    // Position write buffers
+    // Position parity & write buffers
    uint64_t buf_pos = 0, in_pos = 0;
    for (int role = 0; role < pg_size; role++)
    {
        if (stripes[role].req_end != 0)
        {
-            stripes[role].write_buf = request_buf + in_pos;
+            stripes[role].write_buf = write_buf + in_pos;
            in_pos += stripes[role].req_end - stripes[role].req_start;
        }
-        else if (role >= pg_minsize && write_osd_set[role] != 0 && end != 0)
+        else if (role >= pg_minsize && osd_set[role] != 0)
        {
            stripes[role].write_buf = rmw_buf + buf_pos;
            buf_pos += end - start;
@ -359,94 +321,47 @@ static void xor_multiple_buffers(buf_len_t *xor1, int n1, buf_len_t *xor2, int n
    }
 }
-void calc_rmw_parity_xor(osd_rmw_stripe_t *stripes, int pg_size, uint64_t *read_osd_set, uint64_t *write_osd_set, uint32_t chunk_size)
+void calc_rmw_parity(osd_rmw_stripe_t *stripes, int pg_size)
 {
-    int pg_minsize = pg_size-1;
+    if (stripes[pg_size-1].missing)
    {
        // Parity OSD is unavailable
        return;
    }
    for (int role = 0; role < pg_size; role++)
    {
        if (stripes[role].read_end != 0 && stripes[role].missing)
        {
-            // Reconstruct missing stripe (XOR k+1)
+            // Reconstruct missing stripe (EC k+1)
-            reconstruct_stripe_xor(stripes, pg_size, role);
+            reconstruct_stripe(stripes, pg_size, role);
            break;
        }
    }
-    uint32_t start = 0, end = 0;
+    // Calculate new parity (EC k+1)
-    if (write_osd_set[pg_minsize] != 0 || write_osd_set != read_osd_set)
+    int parity = pg_size-1, prev = -2;
    auto wr_end = stripes[parity].write_end;
    auto wr_start = stripes[parity].write_start;
    for (int other = 0; other < pg_size-1; other++)
    {
-        // Required for the next two if()s
+        if (prev == -2)
        for (int role = 0; role < pg_minsize; role++)
        {
-            if (stripes[role].req_end != 0)
+            prev = other;
            {
                start = !end || stripes[role].req_start < start ? stripes[role].req_start : start;
                end = std::max(stripes[role].req_end, end);
            }
        }
-    }
+        else
    if (write_osd_set != read_osd_set)
    {
        for (int role = 0; role < pg_minsize; role++)
        {
-            if (write_osd_set[role] != read_osd_set[role] && write_osd_set[role] != 0 &&
+            int n1 = 0, n2 = 0;
-                (stripes[role].req_start != 0 || stripes[role].req_end != chunk_size))
+            buf_len_t xor1[3], xor2[3];
            if (prev == -1)
            {
-                // Copy modified chunk into the read buffer to write it back
+                xor1[n1++] = { .buf = stripes[parity].write_buf, .len = wr_end-wr_start };
                memcpy(
                    stripes[role].read_buf + stripes[role].req_start,
                    stripes[role].write_buf,
                    stripes[role].req_end - stripes[role].req_start
                );
                stripes[role].write_buf = stripes[role].read_buf;
                stripes[role].write_start = 0;
                stripes[role].write_end = chunk_size;
            }
        }
    }
    if (write_osd_set[pg_minsize] != 0 && end != 0)
    {
        // Calculate new parity (XOR k+1)
        int parity = pg_minsize, prev = -2;
        for (int other = 0; other < pg_minsize; other++)
        {
            if (prev == -2)
            {
                prev = other;
            }
            else
            {
-                int n1 = 0, n2 = 0;
+                get_old_new_buffers(stripes[prev], wr_start, wr_end, xor1, n1);
-                buf_len_t xor1[3], xor2[3];
+                prev = -1;
                if (prev == -1)
                {
                    xor1[n1++] = { .buf = stripes[parity].write_buf, .len = end-start };
                }
                else
                {
                    get_old_new_buffers(stripes[prev], start, end, xor1, n1);
                    prev = -1;
                }
                get_old_new_buffers(stripes[other], start, end, xor2, n2);
                xor_multiple_buffers(xor1, n1, xor2, n2, stripes[parity].write_buf, end-start);
            }
        }
    }
    if (write_osd_set != read_osd_set)
    {
        for (int role = pg_minsize; role < pg_size; role++)
        {
            if (write_osd_set[role] != read_osd_set[role] && (start != 0 || end != chunk_size))
            {
                // Copy new parity into the read buffer to write it back
                memcpy(
                    stripes[role].read_buf + start,
                    stripes[role].write_buf,
                    end - start
                );
                stripes[role].write_buf = stripes[role].read_buf;
                stripes[role].write_start = 0;
                stripes[role].write_end = chunk_size;
            }
            get_old_new_buffers(stripes[other], wr_start, wr_end, xor2, n2);
            xor_multiple_buffers(xor1, n1, xor2, n2, stripes[parity].write_buf, wr_end-wr_start);
        }
    }
 }
--- a/osd_rmw.h
+++ b/osd_rmw.h
@ -1,6 +1,3 @@
 // Copyright (c) Vitaliy Filippov, 2019+
 // License: VNPL-1.0 (see README.md for details)
 #pragma once
 #include <stdint.h>
@ -28,13 +25,12 @@ struct osd_rmw_stripe_t
 void split_stripes(uint64_t pg_minsize, uint32_t bs_block_size, uint32_t start, uint32_t len, osd_rmw_stripe_t *stripes);
-void reconstruct_stripe_xor(osd_rmw_stripe_t *stripes, int pg_size, int role);
+void reconstruct_stripe(osd_rmw_stripe_t *stripes, int pg_size, int role);
 int extend_missing_stripes(osd_rmw_stripe_t *stripes, osd_num_t *osd_set, int minsize, int size);
 void* alloc_read_buffer(osd_rmw_stripe_t *stripes, int read_pg_size, uint64_t add_size);
-void* calc_rmw(void *request_buf, osd_rmw_stripe_t *stripes, uint64_t *read_osd_set,
+void* calc_rmw_reads(void *write_buf, osd_rmw_stripe_t *stripes, uint64_t *osd_set, uint64_t pg_size, uint64_t pg_minsize, uint64_t pg_cursize);
    uint64_t pg_size, uint64_t pg_minsize, uint64_t pg_cursize, uint64_t *write_osd_set, uint64_t chunk_size);
-void calc_rmw_parity_xor(osd_rmw_stripe_t *stripes, int pg_size, uint64_t *read_osd_set, uint64_t *write_osd_set, uint32_t chunk_size);
+void calc_rmw_parity(osd_rmw_stripe_t *stripes, int pg_size);
--- a/osd_rmw_test.cpp
+++ b/osd_rmw_test.cpp
@ -1,151 +1,17 @@
 // Copyright (c) Vitaliy Filippov, 2019+
 // License: VNPL-1.0 (see README.md for details)
 #include <string.h>
 #include "osd_rmw.cpp"
 #include "test_pattern.h"
 void dump_stripes(osd_rmw_stripe_t *stripes, int pg_size);
 void test1();
 void test4();
 void test5();
 void test6();
 void test7();
 void test8();
 void test9();
 /***
 Cases:
 1. split(offset=128K-4K, len=8K)
   = [ [ 128K-4K, 128K ], [ 0, 4K ], [ 0, 0 ] ]
 2. read(offset=128K-4K, len=8K, osd_set=[1,0,3])
   = { read: [ [ 0, 128K ], [ 0, 4K ], [ 0, 4K ] ] }
 3. cover_read(0, 128K, { req: [ 128K-4K, 4K ] })
   = { read: [ 0, 128K-4K ] }
 4. write(offset=128K-4K, len=8K, osd_set=[1,0,3])
   = {
     read: [ [ 0, 128K ], [ 4K, 128K ], [ 4K, 128K ] ],
     write: [ [ 128K-4K, 128K ], [ 0, 4K ], [ 0, 128K ] ],
     input buffer: [ write0, write1 ],
     rmw buffer: [ write2, read0, read1, read2 ],
   }
   + check write2 buffer
 5. write(offset=0, len=128K+64K, osd_set=[1,0,3])
   = {
     req: [ [ 0, 128K ], [ 0, 64K ], [ 0, 0 ] ],
     read: [ [ 64K, 128K ], [ 64K, 128K ], [ 64K, 128K ] ],
     write: [ [ 0, 128K ], [ 0, 64K ], [ 0, 128K ] ],
     input buffer: [ write0, write1 ],
     rmw buffer: [ write2, read0, read1, read2 ],
   }
 6. write(offset=0, len=128K+64K, osd_set=[1,2,3])
   = {
     req: [ [ 0, 128K ], [ 0, 64K ], [ 0, 0 ] ],
     read: [ [ 0, 0 ], [ 64K, 128K ], [ 0, 0 ] ],
     write: [ [ 0, 128K ], [ 0, 64K ], [ 0, 128K ] ],
     input buffer: [ write0, write1 ],
     rmw buffer: [ write2, read1 ],
   }
 7. calc_rmw(offset=128K-4K, len=8K, osd_set=[1,0,3], write_set=[1,2,3])
   = {
     read: [ [ 0, 128K ], [ 0, 128K ], [ 0, 128K ] ],
     write: [ [ 128K-4K, 128K ], [ 0, 4K ], [ 0, 128K ] ],
     input buffer: [ write0, write1 ],
     rmw buffer: [ write2, read0, read1, read2 ],
   }
   then, after calc_rmw_parity_xor(): {
     write: [ [ 128K-4K, 128K ], [ 0, 128K ], [ 0, 128K ] ],
     write1==read1,
   }
   + check write1 buffer
   + check write2 buffer
 8. calc_rmw(offset=0, len=128K+4K, osd_set=[0,2,3], write_set=[1,2,3])
   = {
     read: [ [ 0, 0 ], [ 4K, 128K ], [ 0, 0 ] ],
     write: [ [ 0, 128K ], [ 0, 4K ], [ 0, 128K ] ],
     input buffer: [ write0, write1 ],
     rmw buffer: [ write2, read1 ],
   }
   + check write2 buffer
 9. object recovery case:
   calc_rmw(offset=0, len=0, read_osd_set=[0,2,3], write_osd_set=[1,2,3])
   = {
     read: [ [ 0, 128K ], [ 0, 128K ], [ 0, 128K ] ],
     write: [ [ 0, 0 ], [ 0, 0 ], [ 0, 0 ] ],
     input buffer: NULL,
     rmw buffer: [ read0, read1, read2 ],
   }
   then, after calc_rmw_parity_xor(): {
     write: [ [ 0, 128K ], [ 0, 0 ], [ 0, 0 ] ],
     write0==read0,
   }
   + check write0 buffer
 ***/
 int main(int narg, char *args[])
 {
    // Test 1
    test1();
    // Test 4
    test4();
    // Test 5
    test5();
    // Test 6
    test6();
    // Test 7
    test7();
    // Test 8
    test8();
    // Test 9
    test9();
    // End
    printf("all ok\n");
    return 0;
 }
 void dump_stripes(osd_rmw_stripe_t *stripes, int pg_size)
 {
    printf("request");
    for (int i = 0; i < pg_size; i++)
    {
        printf(" {%uK-%uK}", stripes[i].req_start/1024, stripes[i].req_end/1024);
    }
    printf("\n");
    printf("read");
    for (int i = 0; i < pg_size; i++)
    {
        printf(" {%uK-%uK}", stripes[i].read_start/1024, stripes[i].read_end/1024);
    }
    printf("\n");
    printf("write");
    for (int i = 0; i < pg_size; i++)
    {
        printf(" {%uK-%uK}", stripes[i].write_start/1024, stripes[i].write_end/1024);
    }
    printf("\n");
 }
 void test1()
 {
    osd_num_t osd_set[3] = { 1, 0, 3 };
    osd_rmw_stripe_t stripes[3] = { 0 };
-    // Test 1.1
+    // Test 1
    split_stripes(2, 128*1024, 128*1024-4096, 8192, stripes);
    assert(stripes[0].req_start == 128*1024-4096 && stripes[0].req_end == 128*1024);
    assert(stripes[1].req_start == 0 && stripes[1].req_end == 4096);
    assert(stripes[2].req_end == 0);
-    // Test 1.2
+    // Test 2
    for (int i = 0; i < 3; i++)
    {
        stripes[i].read_start = stripes[i].req_start;
@ -154,26 +20,18 @@ void test1()
    assert(extend_missing_stripes(stripes, osd_set, 2, 3) == 0);
    assert(stripes[0].read_start == 0 && stripes[0].read_end == 128*1024);
    assert(stripes[2].read_start == 0 && stripes[2].read_end == 4096);
-    // Test 1.3
+    // Test 3
    stripes[0] = { .req_start = 128*1024-4096, .req_end = 128*1024 };
    cover_read(0, 128*1024, stripes[0]);
    assert(stripes[0].read_start == 0 && stripes[0].read_end == 128*1024-4096);
 }
 void test4()
 {
    osd_num_t osd_set[3] = { 1, 0, 3 };
    osd_rmw_stripe_t stripes[3] = { 0 };
    // Test 4.1
    memset(stripes, 0, sizeof(stripes));
    split_stripes(2, 128*1024, 128*1024-4096, 8192, stripes);
    void* write_buf = malloc(8192);
-    void* rmw_buf = calc_rmw(write_buf, stripes, osd_set, 3, 2, 2, osd_set, 128*1024);
+    void* rmw_buf = calc_rmw_reads(write_buf, stripes, osd_set, 3, 2, 2);
    assert(stripes[0].read_start == 0 && stripes[0].read_end == 128*1024);
    assert(stripes[1].read_start == 4096 && stripes[1].read_end == 128*1024);
    assert(stripes[2].read_start == 4096 && stripes[2].read_end == 128*1024);
    assert(stripes[0].write_start == 128*1024-4096 && stripes[0].write_end == 128*1024);
    assert(stripes[1].write_start == 0 && stripes[1].write_end == 4096);
    assert(stripes[2].write_start == 0 && stripes[2].write_end == 128*1024);
    assert(stripes[0].read_buf == rmw_buf+128*1024);
    assert(stripes[1].read_buf == rmw_buf+128*1024*2);
    assert(stripes[2].read_buf == rmw_buf+128*1024*3-4096);
@ -185,32 +43,24 @@ void test4()
    set_pattern(stripes[0].read_buf, 128*1024, PATTERN1); // old data
    set_pattern(stripes[1].read_buf, 128*1024-4096, UINT64_MAX); // didn't read it, it's missing
    set_pattern(stripes[2].read_buf, 128*1024-4096, 0); // old parity = 0
-    calc_rmw_parity_xor(stripes, 3, osd_set, osd_set, 128*1024);
+    calc_rmw_parity(stripes, 3);
    check_pattern(stripes[2].write_buf, 4096, PATTERN0^PATTERN1); // new parity
    check_pattern(stripes[2].write_buf+4096, 128*1024-4096*2, 0); // new parity
    check_pattern(stripes[2].write_buf+128*1024-4096, 4096, PATTERN0^PATTERN1); // new parity
    free(rmw_buf);
    free(write_buf);
 }
 void test5()
 {
    osd_num_t osd_set[3] = { 1, 0, 3 };
    osd_rmw_stripe_t stripes[3] = { 0 };
    // Test 5.1
    memset(stripes, 0, sizeof(stripes));
    split_stripes(2, 128*1024, 0, 64*1024*3, stripes);
    assert(stripes[0].req_start == 0 && stripes[0].req_end == 128*1024);
    assert(stripes[1].req_start == 0 && stripes[1].req_end == 64*1024);
    assert(stripes[2].req_end == 0);
    // Test 5.2
-    void *write_buf = malloc(64*1024*3);
+    write_buf = malloc(64*1024*3);
-    void *rmw_buf = calc_rmw(write_buf, stripes, osd_set, 3, 2, 2, osd_set, 128*1024);
+    rmw_buf = calc_rmw_reads(write_buf, stripes, osd_set, 3, 2, 2);
    assert(stripes[0].read_start == 64*1024 && stripes[0].read_end == 128*1024);
    assert(stripes[1].read_start == 64*1024 && stripes[1].read_end == 128*1024);
    assert(stripes[2].read_start == 64*1024 && stripes[2].read_end == 128*1024);
    assert(stripes[0].write_start == 0 && stripes[0].write_end == 128*1024);
    assert(stripes[1].write_start == 0 && stripes[1].write_end == 64*1024);
    assert(stripes[2].write_start == 0 && stripes[2].write_end == 128*1024);
    assert(stripes[0].read_buf == rmw_buf+128*1024);
    assert(stripes[1].read_buf == rmw_buf+64*3*1024);
    assert(stripes[2].read_buf == rmw_buf+64*4*1024);
@ -219,22 +69,15 @@ void test5()
    assert(stripes[2].write_buf == rmw_buf);
    free(rmw_buf);
    free(write_buf);
 }
 void test6()
 {
    osd_num_t osd_set[3] = { 1, 2, 3 };
    osd_rmw_stripe_t stripes[3] = { 0 };
    // Test 6.1
    memset(stripes, 0, sizeof(stripes));
    split_stripes(2, 128*1024, 0, 64*1024*3, stripes);
-    void *write_buf = malloc(64*1024*3);
+    osd_set[1] = 2;
-    void *rmw_buf = calc_rmw(write_buf, stripes, osd_set, 3, 2, 3, osd_set, 128*1024);
+    write_buf = malloc(64*1024*3);
    rmw_buf = calc_rmw_reads(write_buf, stripes, osd_set, 3, 2, 3);
    assert(stripes[0].read_end == 0);
    assert(stripes[1].read_start == 64*1024 && stripes[1].read_end == 128*1024);
    assert(stripes[2].read_end == 0);
    assert(stripes[0].write_start == 0 && stripes[0].write_end == 128*1024);
    assert(stripes[1].write_start == 0 && stripes[1].write_end == 64*1024);
    assert(stripes[2].write_start == 0 && stripes[2].write_end == 128*1024);
    assert(stripes[0].read_buf == 0);
    assert(stripes[1].read_buf == rmw_buf+128*1024);
    assert(stripes[2].read_buf == 0);
@ -243,121 +86,8 @@ void test6()
    assert(stripes[2].write_buf == rmw_buf);
    free(rmw_buf);
    free(write_buf);
-}
+    osd_set[1] = 0;
-
+    // End
-void test7()
+    printf("all ok\n");
-{
+    return 0;
    osd_num_t osd_set[3] = { 1, 0, 3 };
    osd_num_t write_osd_set[3] = { 1, 2, 3 };
    osd_rmw_stripe_t stripes[3] = { 0 };
    // Test 7.1
    split_stripes(2, 128*1024, 128*1024-4096, 8192, stripes);
    void *write_buf = malloc(8192);
    void *rmw_buf = calc_rmw(write_buf, stripes, osd_set, 3, 2, 2, write_osd_set, 128*1024);
    assert(stripes[0].read_start == 0 && stripes[0].read_end == 128*1024);
    assert(stripes[1].read_start == 0 && stripes[1].read_end == 128*1024);
    assert(stripes[2].read_start == 0 && stripes[2].read_end == 128*1024);
    assert(stripes[0].write_start == 128*1024-4096 && stripes[0].write_end == 128*1024);
    assert(stripes[1].write_start == 0 && stripes[1].write_end == 4096);
    assert(stripes[2].write_start == 0 && stripes[2].write_end == 128*1024);
    assert(stripes[0].read_buf == rmw_buf+128*1024);
    assert(stripes[1].read_buf == rmw_buf+128*1024*2);
    assert(stripes[2].read_buf == rmw_buf+128*1024*3);
    assert(stripes[0].write_buf == write_buf);
    assert(stripes[1].write_buf == write_buf+4096);
    assert(stripes[2].write_buf == rmw_buf);
    // Test 7.2
    set_pattern(write_buf, 8192, PATTERN0);
    set_pattern(stripes[0].read_buf, 128*1024, PATTERN1); // old data
    set_pattern(stripes[1].read_buf, 128*1024, UINT64_MAX); // didn't read it, it's missing
    set_pattern(stripes[2].read_buf, 128*1024, 0); // old parity = 0
    calc_rmw_parity_xor(stripes, 3, osd_set, write_osd_set, 128*1024);
    assert(stripes[0].write_start == 128*1024-4096 && stripes[0].write_end == 128*1024);
    assert(stripes[1].write_start == 0 && stripes[1].write_end == 128*1024);
    assert(stripes[2].write_start == 0 && stripes[2].write_end == 128*1024);
    assert(stripes[1].write_buf == stripes[1].read_buf);
    check_pattern(stripes[1].write_buf, 4096, PATTERN0);
    check_pattern(stripes[1].write_buf+4096, 128*1024-4096, PATTERN1);
    check_pattern(stripes[2].write_buf, 4096, PATTERN0^PATTERN1); // new parity
    check_pattern(stripes[2].write_buf+4096, 128*1024-4096*2, 0); // new parity
    check_pattern(stripes[2].write_buf+128*1024-4096, 4096, PATTERN0^PATTERN1); // new parity
    free(rmw_buf);
    free(write_buf);
 }
 void test8()
 {
    osd_num_t osd_set[3] = { 0, 2, 3 };
    osd_num_t write_osd_set[3] = { 1, 2, 3 };
    osd_rmw_stripe_t stripes[3] = { 0 };
    // Test 8.1
    split_stripes(2, 128*1024, 0, 128*1024+4096, stripes);
    void *write_buf = malloc(128*1024+4096);
    void *rmw_buf = calc_rmw(write_buf, stripes, osd_set, 3, 2, 2, write_osd_set, 128*1024);
    assert(stripes[0].read_start == 0 && stripes[0].read_end == 0);
    assert(stripes[1].read_start == 4096 && stripes[1].read_end == 128*1024);
    assert(stripes[2].read_start == 0 && stripes[2].read_end == 0);
    assert(stripes[0].write_start == 0 && stripes[0].write_end == 128*1024);
    assert(stripes[1].write_start == 0 && stripes[1].write_end == 4096);
    assert(stripes[2].write_start == 0 && stripes[2].write_end == 128*1024);
    assert(stripes[0].read_buf == NULL);
    assert(stripes[1].read_buf == rmw_buf+128*1024);
    assert(stripes[2].read_buf == NULL);
    assert(stripes[0].write_buf == write_buf);
    assert(stripes[1].write_buf == write_buf+128*1024);
    assert(stripes[2].write_buf == rmw_buf);
    // Test 8.2
    set_pattern(write_buf, 128*1024+4096, PATTERN0);
    set_pattern(stripes[1].read_buf, 128*1024-4096, PATTERN1);
    calc_rmw_parity_xor(stripes, 3, osd_set, write_osd_set, 128*1024);
    assert(stripes[0].write_start == 0 && stripes[0].write_end == 128*1024); // recheck again
    assert(stripes[1].write_start == 0 && stripes[1].write_end == 4096);     // recheck again
    assert(stripes[2].write_start == 0 && stripes[2].write_end == 128*1024); // recheck again
    assert(stripes[0].write_buf == write_buf);                               // recheck again
    assert(stripes[1].write_buf == write_buf+128*1024);                      // recheck again
    assert(stripes[2].write_buf == rmw_buf);                                 // recheck again
    check_pattern(stripes[2].write_buf, 4096, 0); // new parity
    check_pattern(stripes[2].write_buf+4096, 128*1024-4096, PATTERN0^PATTERN1); // new parity
    free(rmw_buf);
    free(write_buf);
 }
 void test9()
 {
    osd_num_t osd_set[3] = { 0, 2, 3 };
    osd_num_t write_osd_set[3] = { 1, 2, 3 };
    osd_rmw_stripe_t stripes[3] = { 0 };
    // Test 9.0
    split_stripes(2, 128*1024, 64*1024, 0, stripes);
    assert(stripes[0].req_start == 0 && stripes[0].req_end == 0);
    assert(stripes[1].req_start == 0 && stripes[1].req_end == 0);
    assert(stripes[2].req_start == 0 && stripes[2].req_end == 0);
    // Test 9.1
    void *write_buf = NULL;
    void *rmw_buf = calc_rmw(write_buf, stripes, osd_set, 3, 2, 3, write_osd_set, 128*1024);
    assert(stripes[0].read_start == 0 && stripes[0].read_end == 128*1024);
    assert(stripes[1].read_start == 0 && stripes[1].read_end == 128*1024);
    assert(stripes[2].read_start == 0 && stripes[2].read_end == 128*1024);
    assert(stripes[0].write_start == 0 && stripes[0].write_end == 0);
    assert(stripes[1].write_start == 0 && stripes[1].write_end == 0);
    assert(stripes[2].write_start == 0 && stripes[2].write_end == 0);
    assert(stripes[0].read_buf == rmw_buf);
    assert(stripes[1].read_buf == rmw_buf+128*1024);
    assert(stripes[2].read_buf == rmw_buf+128*1024*2);
    assert(stripes[0].write_buf == NULL);
    assert(stripes[1].write_buf == NULL);
    assert(stripes[2].write_buf == NULL);
    // Test 9.2
    set_pattern(stripes[1].read_buf, 128*1024, 0);
    set_pattern(stripes[2].read_buf, 128*1024, PATTERN1);
    calc_rmw_parity_xor(stripes, 3, osd_set, write_osd_set, 128*1024);
    assert(stripes[0].write_start == 0 && stripes[0].write_end == 128*1024);
    assert(stripes[1].write_start == 0 && stripes[1].write_end == 0);
    assert(stripes[2].write_start == 0 && stripes[2].write_end == 0);
    assert(stripes[0].write_buf == rmw_buf);
    assert(stripes[1].write_buf == NULL);
    assert(stripes[2].write_buf == NULL);
    check_pattern(stripes[0].read_buf, 128*1024, PATTERN1);
    check_pattern(stripes[0].write_buf, 128*1024, PATTERN1);
    free(rmw_buf);
 }
--- a/osd_secondary.cpp
+++ b/osd_secondary.cpp
@ -1,59 +1,64 @@
 // Copyright (c) Vitaliy Filippov, 2019+
 // License: VNPL-1.0 (see README.md for details)
 #include "osd.h"
 #include "json11/json11.hpp"
 void osd_t::secondary_op_callback(osd_op_t *op)
 {
-    if (op->req.hdr.opcode == OSD_OP_SEC_READ ||
+    inflight_ops--;
-        op->req.hdr.opcode == OSD_OP_SEC_WRITE ||
+    auto cl_it = clients.find(op->peer_fd);
-        op->req.hdr.opcode == OSD_OP_SEC_WRITE_STABLE)
+    if (cl_it != clients.end())
    {
-        op->reply.sec_rw.version = op->bs_op->version;
+        op->reply.hdr.magic = SECONDARY_OSD_REPLY_MAGIC;
-    }
+        op->reply.hdr.id = op->req.hdr.id;
-    else if (op->req.hdr.opcode == OSD_OP_SEC_DELETE)
+        op->reply.hdr.opcode = op->req.hdr.opcode;
-    {
+        op->reply.hdr.retval = op->bs_op->retval;
-        op->reply.sec_del.version = op->bs_op->version;
+        if (op->req.hdr.opcode == OSD_OP_SECONDARY_READ ||
-    }
+            op->req.hdr.opcode == OSD_OP_SECONDARY_WRITE)
    if (op->req.hdr.opcode == OSD_OP_SEC_READ &&
        op->bs_op->retval > 0)
    {
        op->iov.push_back(op->buf, op->bs_op->retval);
    }
    else if (op->req.hdr.opcode == OSD_OP_SEC_LIST)
    {
        // allocated by blockstore
        op->buf = op->bs_op->buf;
        if (op->bs_op->retval > 0)
        {
-            op->iov.push_back(op->buf, op->bs_op->retval * sizeof(obj_ver_id));
+            op->reply.sec_rw.version = op->bs_op->version;
        }
-        op->reply.sec_list.stable_count = op->bs_op->version;
+        else if (op->req.hdr.opcode == OSD_OP_SECONDARY_DELETE)
        {
            op->reply.sec_del.version = op->bs_op->version;
        }
        if (op->req.hdr.opcode == OSD_OP_SECONDARY_READ &&
            op->reply.hdr.retval > 0)
        {
            op->send_list.push_back(op->buf, op->reply.hdr.retval);
        }
        else if (op->req.hdr.opcode == OSD_OP_SECONDARY_LIST)
        {
            // allocated by blockstore
            op->buf = op->bs_op->buf;
            if (op->reply.hdr.retval > 0)
            {
                op->send_list.push_back(op->buf, op->reply.hdr.retval * sizeof(obj_ver_id));
            }
            op->reply.sec_list.stable_count = op->bs_op->version;
        }
        auto & cl = cl_it->second;
        outbox_push(cl, op);
    }
    else
    {
        delete op;
    }
    int retval = op->bs_op->retval;
    delete op->bs_op;
    op->bs_op = NULL;
    finish_op(op, retval);
 }
 void osd_t::exec_secondary(osd_op_t *cur_op)
 {
    cur_op->bs_op = new blockstore_op_t();
    cur_op->bs_op->callback = [this, cur_op](blockstore_op_t* bs_op) { secondary_op_callback(cur_op); };
-    cur_op->bs_op->opcode = (cur_op->req.hdr.opcode == OSD_OP_SEC_READ ? BS_OP_READ
+    cur_op->bs_op->opcode = (cur_op->req.hdr.opcode == OSD_OP_SECONDARY_READ ? BS_OP_READ
-        : (cur_op->req.hdr.opcode == OSD_OP_SEC_WRITE ? BS_OP_WRITE
+        : (cur_op->req.hdr.opcode == OSD_OP_SECONDARY_WRITE ? BS_OP_WRITE
-        : (cur_op->req.hdr.opcode == OSD_OP_SEC_WRITE_STABLE ? BS_OP_WRITE_STABLE
+        : (cur_op->req.hdr.opcode == OSD_OP_SECONDARY_SYNC ? BS_OP_SYNC
-        : (cur_op->req.hdr.opcode == OSD_OP_SEC_SYNC ? BS_OP_SYNC
+        : (cur_op->req.hdr.opcode == OSD_OP_SECONDARY_STABILIZE ? BS_OP_STABLE
-        : (cur_op->req.hdr.opcode == OSD_OP_SEC_STABILIZE ? BS_OP_STABLE
+        : (cur_op->req.hdr.opcode == OSD_OP_SECONDARY_ROLLBACK ? BS_OP_ROLLBACK
-        : (cur_op->req.hdr.opcode == OSD_OP_SEC_ROLLBACK ? BS_OP_ROLLBACK
+        : (cur_op->req.hdr.opcode == OSD_OP_SECONDARY_DELETE ? BS_OP_DELETE
-        : (cur_op->req.hdr.opcode == OSD_OP_SEC_DELETE ? BS_OP_DELETE
+        : (cur_op->req.hdr.opcode == OSD_OP_SECONDARY_LIST ? BS_OP_LIST
-        : (cur_op->req.hdr.opcode == OSD_OP_SEC_LIST ? BS_OP_LIST
+        : -1)))))));
-        : -1))))))));
+    if (cur_op->req.hdr.opcode == OSD_OP_SECONDARY_READ ||
-    if (cur_op->req.hdr.opcode == OSD_OP_SEC_READ ||
+        cur_op->req.hdr.opcode == OSD_OP_SECONDARY_WRITE)
        cur_op->req.hdr.opcode == OSD_OP_SEC_WRITE ||
        cur_op->req.hdr.opcode == OSD_OP_SEC_WRITE_STABLE)
    {
        cur_op->bs_op->oid = cur_op->req.sec_rw.oid;
        cur_op->bs_op->version = cur_op->req.sec_rw.version;
@ -64,7 +69,7 @@ void osd_t::exec_secondary(osd_op_t *cur_op)
        cur_op->bs_op->retval = cur_op->bs_op->len;
 #endif
    }
-    else if (cur_op->req.hdr.opcode == OSD_OP_SEC_DELETE)
+    else if (cur_op->req.hdr.opcode == OSD_OP_SECONDARY_DELETE)
    {
        cur_op->bs_op->oid = cur_op->req.sec_del.oid;
        cur_op->bs_op->version = cur_op->req.sec_del.version;
@ -72,8 +77,8 @@ void osd_t::exec_secondary(osd_op_t *cur_op)
        cur_op->bs_op->retval = 0;
 #endif
    }
-    else if (cur_op->req.hdr.opcode == OSD_OP_SEC_STABILIZE ||
+    else if (cur_op->req.hdr.opcode == OSD_OP_SECONDARY_STABILIZE ||
-        cur_op->req.hdr.opcode == OSD_OP_SEC_ROLLBACK)
+        cur_op->req.hdr.opcode == OSD_OP_SECONDARY_ROLLBACK)
    {
        cur_op->bs_op->len = cur_op->req.sec_stab.len/sizeof(obj_ver_id);
        cur_op->bs_op->buf = cur_op->buf;
@ -81,21 +86,18 @@ void osd_t::exec_secondary(osd_op_t *cur_op)
        cur_op->bs_op->retval = 0;
 #endif
    }
-    else if (cur_op->req.hdr.opcode == OSD_OP_SEC_LIST)
+    else if (cur_op->req.hdr.opcode == OSD_OP_SECONDARY_LIST)
    {
        if (cur_op->req.sec_list.pg_count < cur_op->req.sec_list.list_pg)
        {
            // requested pg number is greater than total pg count
            printf("Invalid LIST request: pg count %u < pg number %u\n", cur_op->req.sec_list.pg_count, cur_op->req.sec_list.list_pg);
            cur_op->bs_op->retval = -EINVAL;
            secondary_op_callback(cur_op);
            return;
        }
-        cur_op->bs_op->oid.stripe = cur_op->req.sec_list.pg_stripe_size;
+        cur_op->bs_op->oid.stripe = cur_op->req.sec_list.parity_block_size;
        cur_op->bs_op->len = cur_op->req.sec_list.pg_count;
        cur_op->bs_op->offset = cur_op->req.sec_list.list_pg - 1;
        cur_op->bs_op->oid.inode = cur_op->req.sec_list.min_inode;
        cur_op->bs_op->version = cur_op->req.sec_list.max_inode;
 #ifdef OSD_STUB
        cur_op->bs_op->retval = 0;
        cur_op->bs_op->buf = NULL;
@ -112,10 +114,15 @@ void osd_t::exec_show_config(osd_op_t *cur_op)
 {
    // FIXME: Send the real config, not its source
    std::string cfg_str = json11::Json(config).dump();
-    cur_op->buf = malloc_or_die(cfg_str.size()+1);
+    cur_op->reply.hdr.magic = SECONDARY_OSD_REPLY_MAGIC;
    cur_op->reply.hdr.id = cur_op->req.hdr.id;
    cur_op->reply.hdr.opcode = cur_op->req.hdr.opcode;
    cur_op->reply.hdr.retval = cfg_str.size()+1;
    cur_op->buf = malloc(cfg_str.size()+1);
    memcpy(cur_op->buf, cfg_str.c_str(), cfg_str.size()+1);
-    cur_op->iov.push_back(cur_op->buf, cfg_str.size()+1);
+    auto & cl = clients[cur_op->peer_fd];
-    finish_op(cur_op, cfg_str.size()+1);
+    cur_op->send_list.push_back(cur_op->buf, cur_op->reply.hdr.retval);
    outbox_push(cl, cur_op);
 }
 void osd_t::exec_sync_stab_all(osd_op_t *cur_op)
--- a/osd_send.cpp
+++ b/osd_send.cpp
@ -0,0 +1,133 @@
 #include "osd.h"
 void osd_t::outbox_push(osd_client_t & cl, osd_op_t *cur_op)
 {
    assert(cur_op->peer_fd);
    if (cur_op->op_type == OSD_OP_OUT)
    {
        clock_gettime(CLOCK_REALTIME, &cur_op->tv_begin);
    }
    cl.outbox.push_back(cur_op);
    if (cl.write_op || cl.outbox.size() > 1 || !try_send(cl))
    {
        if (cl.write_state == 0)
        {
            cl.write_state = CL_WRITE_READY;
            write_ready_clients.push_back(cur_op->peer_fd);
        }
        ringloop->wakeup();
    }
 }
 bool osd_t::try_send(osd_client_t & cl)
 {
    int peer_fd = cl.peer_fd;
    io_uring_sqe* sqe = ringloop->get_sqe();
    if (!sqe)
    {
        return false;
    }
    ring_data_t* data = ((ring_data_t*)sqe->user_data);
    if (!cl.write_op)
    {
        // pick next command
        cl.write_op = cl.outbox.front();
        cl.outbox.pop_front();
        cl.write_state = CL_WRITE_REPLY;
        clock_gettime(CLOCK_REALTIME, &cl.write_op->tv_send);
        if (cl.write_op->op_type == OSD_OP_IN)
        {
            // Measure execution latency
            timespec tv_end = cl.write_op->tv_send;
            op_stat_count[cl.write_op->req.hdr.opcode]++;
            op_stat_sum[cl.write_op->req.hdr.opcode] += (
                (tv_end.tv_sec - cl.write_op->tv_begin.tv_sec)*1000000 +
                (tv_end.tv_nsec - cl.write_op->tv_begin.tv_nsec)/1000
            );
        }
    }
    cl.write_msg.msg_iov = cl.write_op->send_list.get_iovec();
    cl.write_msg.msg_iovlen = cl.write_op->send_list.get_size();
    data->callback = [this, peer_fd](ring_data_t *data) { handle_send(data, peer_fd); };
    my_uring_prep_sendmsg(sqe, cl.peer_fd_index, &cl.write_msg, 0);
    sqe->flags |= IOSQE_FIXED_FILE;
    return true;
 }
 void osd_t::send_replies()
 {
    for (int i = 0; i < write_ready_clients.size(); i++)
    {
        int peer_fd = write_ready_clients[i];
        if (!try_send(clients[peer_fd]))
        {
            write_ready_clients.erase(write_ready_clients.begin(), write_ready_clients.begin() + i);
            return;
        }
    }
    write_ready_clients.clear();
 }
 void osd_t::handle_send(ring_data_t *data, int peer_fd)
 {
    int res = data->res;
    auto cl_it = clients.find(peer_fd);
    if (cl_it != clients.end())
    {
        auto & cl = cl_it->second;
        if (res < 0 && res != -EAGAIN)
        {
            // this is a client socket, so don't panic. just disconnect it
            printf("Client %d socket write error: %d (%s). Disconnecting client\n", peer_fd, -res, strerror(-res));
            stop_client(peer_fd);
            return;
        }
        if (res >= 0)
        {
            osd_op_t *cur_op = cl.write_op;
            while (res > 0 && cur_op->send_list.sent < cur_op->send_list.count)
            {
                iovec & iov = cur_op->send_list.buf[cur_op->send_list.sent];
                if (iov.iov_len <= res)
                {
                    res -= iov.iov_len;
                    cur_op->send_list.sent++;
                }
                else
                {
                    iov.iov_len -= res;
                    iov.iov_base += res;
                    break;
                }
            }
            if (cur_op->send_list.sent >= cur_op->send_list.count)
            {
                // Done
                if (cur_op->req.hdr.opcode == OSD_OP_SECONDARY_STABILIZE)
                {
                    timespec tv_end;
                    clock_gettime(CLOCK_REALTIME, &tv_end);
                    send_stat_count++;
                    send_stat_sum += (
                        (tv_end.tv_sec - cl.write_op->tv_send.tv_sec)*1000000 +
                        (tv_end.tv_nsec - cl.write_op->tv_send.tv_nsec)/1000
                    );
                }
                if (cur_op->op_type == OSD_OP_IN)
                {
                    delete cur_op;
                }
                else
                {
                    cl.sent_ops[cl.write_op->req.hdr.id] = cl.write_op;
                }
                cl.write_op = NULL;
                cl.write_state = cl.outbox.size() > 0 ? CL_WRITE_READY : 0;
            }
        }
        if (cl.write_state != 0)
        {
            write_ready_clients.push_back(peer_fd);
        }
    }
 }
--- a/osd_test.cpp
+++ b/osd_test.cpp
@ -1,6 +1,3 @@
 // Copyright (c) Vitaliy Filippov, 2019+
 // License: VNPL-1.0 (see README.md for details)
 #include <sys/types.h>
 #include <sys/socket.h>
 #include <netinet/in.h>
@ -22,8 +19,6 @@
 int connect_osd(const char *osd_address, int osd_port);
 uint64_t test_read(int connect_fd, uint64_t inode, uint64_t stripe, uint64_t version, uint64_t offset, uint64_t len);
 uint64_t test_write(int connect_fd, uint64_t inode, uint64_t stripe, uint64_t version, uint64_t pattern);
 void* test_primary_read(int connect_fd, uint64_t inode, uint64_t offset, uint64_t len);
@ -34,8 +29,6 @@ void test_primary_sync(int connect_fd);
 void test_sync_stab_all(int connect_fd);
 void test_list_stab(int connect_fd);
 int main0(int narg, char *args[])
 {
    int connect_fd;
@ -101,16 +94,7 @@ int main2(int narg, char *args[])
    return 0;
 }
-int main3(int narg, char *args[])
+int main(int narg, char *args[])
 {
    int connect_fd;
    connect_fd = connect_osd("127.0.0.1", 11203);
    test_list_stab(connect_fd);
    close(connect_fd);
    return 0;
 }
 int main4(int narg, char *args[])
 {
    int connect_fd;
    // Cluster write (sync not implemented yet)
@ -122,15 +106,6 @@ int main4(int narg, char *args[])
    return 0;
 }
 int main(int narg, char *args[])
 {
    int connect_fd;
    connect_fd = connect_osd("192.168.7.2", 43051);
    test_read(connect_fd, 1, 1039663104, UINT64_MAX, 0, 128*1024);
    close(connect_fd);
    return 0;
 }
 int connect_osd(const char *osd_address, int osd_port)
 {
    struct sockaddr_in addr;
@ -173,7 +148,7 @@ bool check_reply(int r, osd_any_op_t & op, osd_any_reply_t & reply, int expected
        printf("bad reply: magic, id or opcode does not match request\n");
        return false;
    }
-    if (expected >= 0 && reply.hdr.retval != expected)
+    if (reply.hdr.retval != expected)
    {
        printf("operation failed, retval=%ld\n", reply.hdr.retval);
        return false;
@ -181,73 +156,13 @@ bool check_reply(int r, osd_any_op_t & op, osd_any_reply_t & reply, int expected
    return true;
 }
 uint64_t test_read(int connect_fd, uint64_t inode, uint64_t stripe, uint64_t version, uint64_t offset, uint64_t len)
 {
    osd_any_op_t op;
    osd_any_reply_t reply;
    op.hdr.magic = SECONDARY_OSD_OP_MAGIC;
    op.hdr.id = 1;
    op.hdr.opcode = OSD_OP_SEC_READ;
    op.sec_rw.oid = {
        .inode = inode,
        .stripe = stripe,
    };
    op.sec_rw.version = version;
    op.sec_rw.offset = offset;
    op.sec_rw.len = len;
    void *data = memalign(MEM_ALIGNMENT, op.sec_rw.len);
    write_blocking(connect_fd, op.buf, OSD_PACKET_SIZE);
    int r = read_blocking(connect_fd, reply.buf, OSD_PACKET_SIZE);
    if (!check_reply(r, op, reply, op.sec_rw.len))
    {
        free(data);
        return 0;
    }
    r = read_blocking(connect_fd, data, len);
    if (r != len)
    {
        free(data);
        perror("read data");
        return 0;
    }
    free(data);
    printf("Read %lx:%lx v%lu = v%lu\n", inode, stripe, version, reply.sec_rw.version);
    op.hdr.opcode = OSD_OP_SEC_LIST;
    op.sec_list.list_pg = 1;
    op.sec_list.pg_count = 1;
    op.sec_list.pg_stripe_size = 4*1024*1024;
    write_blocking(connect_fd, op.buf, OSD_PACKET_SIZE);
    r = read_blocking(connect_fd, reply.buf, OSD_PACKET_SIZE);
    if (reply.hdr.retval < 0 || !check_reply(r, op, reply, reply.hdr.retval))
    {
        return 0;
    }
    data = memalign(MEM_ALIGNMENT, sizeof(obj_ver_id)*reply.hdr.retval);
    r = read_blocking(connect_fd, data, sizeof(obj_ver_id)*reply.hdr.retval);
    if (r != sizeof(obj_ver_id)*reply.hdr.retval)
    {
        free(data);
        perror("read data");
        return 0;
    }
    obj_ver_id *ov = (obj_ver_id*)data;
    for (int i = 0; i < reply.hdr.retval; i++)
    {
        if (ov[i].oid.inode == inode && (ov[i].oid.stripe & ~(4096-1)) == (stripe & ~(4096-1)))
        {
            printf("list: %lx:%lx v%lu stable=%d\n", ov[i].oid.inode, ov[i].oid.stripe, ov[i].version, i < reply.sec_list.stable_count ? 1 : 0);
        }
    }
    return 0;
 }
 uint64_t test_write(int connect_fd, uint64_t inode, uint64_t stripe, uint64_t version, uint64_t pattern)
 {
    osd_any_op_t op;
    osd_any_reply_t reply;
    op.hdr.magic = SECONDARY_OSD_OP_MAGIC;
    op.hdr.id = 1;
-    op.hdr.opcode = OSD_OP_SEC_WRITE;
+    op.hdr.opcode = OSD_OP_SECONDARY_WRITE;
    op.sec_rw.oid = {
        .inode = inode,
        .stripe = stripe,
@ -255,7 +170,7 @@ uint64_t test_write(int connect_fd, uint64_t inode, uint64_t stripe, uint64_t ve
    op.sec_rw.version = version;
    op.sec_rw.offset = 0;
    op.sec_rw.len = 128*1024;
-    void *data = memalign(MEM_ALIGNMENT, op.sec_rw.len);
+    void *data = memalign(512, op.sec_rw.len);
    for (int i = 0; i < (op.sec_rw.len)/sizeof(uint64_t); i++)
        ((uint64_t*)data)[i] = pattern;
    write_blocking(connect_fd, op.buf, OSD_PACKET_SIZE);
@ -290,7 +205,7 @@ void* test_primary_read(int connect_fd, uint64_t inode, uint64_t offset, uint64_
    op.rw.inode = inode;
    op.rw.offset = offset;
    op.rw.len = len;
-    void *data = memalign(MEM_ALIGNMENT, len);
+    void *data = memalign(512, len);
    write_blocking(connect_fd, op.buf, OSD_PACKET_SIZE);
    int r = read_blocking(connect_fd, reply.buf, OSD_PACKET_SIZE);
    if (!check_reply(r, op, reply, len))
@ -318,7 +233,7 @@ void test_primary_write(int connect_fd, uint64_t inode, uint64_t offset, uint64_
    op.rw.inode = inode;
    op.rw.offset = offset;
    op.rw.len = len;
-    void *data = memalign(MEM_ALIGNMENT, len);
+    void *data = memalign(512, len);
    set_pattern(data, len, pattern);
    write_blocking(connect_fd, op.buf, OSD_PACKET_SIZE);
    write_blocking(connect_fd, data, len);
@ -350,40 +265,3 @@ void test_sync_stab_all(int connect_fd)
    int r = read_blocking(connect_fd, reply.buf, OSD_PACKET_SIZE);
    assert(check_reply(r, op, reply, 0));
 }
 void test_list_stab(int connect_fd)
 {
    osd_any_op_t op;
    osd_any_reply_t reply;
    op.hdr.magic = SECONDARY_OSD_OP_MAGIC;
    op.hdr.id = 1;
    op.hdr.opcode = OSD_OP_SEC_LIST;
    op.sec_list.pg_count = 0;
    assert(write_blocking(connect_fd, op.buf, OSD_PACKET_SIZE) == OSD_PACKET_SIZE);
    int r = read_blocking(connect_fd, reply.buf, OSD_PACKET_SIZE);
    assert(check_reply(r, op, reply, -1));
    int total_count = reply.hdr.retval;
    int stable_count = reply.sec_list.stable_count;
    obj_ver_id *data = (obj_ver_id*)malloc(total_count * sizeof(obj_ver_id));
    assert(data);
    assert(read_blocking(connect_fd, data, total_count * sizeof(obj_ver_id)) == (total_count * sizeof(obj_ver_id)));
    int last_start = stable_count;
    for (int i = stable_count; i <= total_count; i++)
    {
        // Stabilize in portions of 32 entries
        if (i - last_start >= 32 || i == total_count)
        {
            op.hdr.opcode = OSD_OP_SEC_STABILIZE;
            op.sec_stab.len = sizeof(obj_ver_id) * (i - last_start);
            assert(write_blocking(connect_fd, op.buf, OSD_PACKET_SIZE) == OSD_PACKET_SIZE);
            assert(write_blocking(connect_fd, data + last_start, op.sec_stab.len) == op.sec_stab.len);
            r = read_blocking(connect_fd, reply.buf, OSD_PACKET_SIZE);
            assert(check_reply(r, op, reply, 0));
            last_start = i;
        }
    }
    obj_ver_id *data2 = (obj_ver_id*)malloc(sizeof(obj_ver_id) * 32);
    assert(data2);
    free(data2);
    free(data);
 }
--- a/pg_states.cpp
+++ b/pg_states.cpp
@ -1,38 +0,0 @@
 // Copyright (c) Vitaliy Filippov, 2019+
 // License: VNPL-1.0 or GNU GPL-2.0+ (see README.md for details)
 #include "pg_states.h"
 const int pg_state_bit_count = 14;
 const int pg_state_bits[14] = {
    PG_STARTING,
    PG_PEERING,
    PG_INCOMPLETE,
    PG_ACTIVE,
    PG_STOPPING,
    PG_OFFLINE,
    PG_DEGRADED,
    PG_HAS_INCOMPLETE,
    PG_HAS_DEGRADED,
    PG_HAS_MISPLACED,
    PG_HAS_UNCLEAN,
    PG_HAS_INVALID,
    PG_LEFT_ON_DEAD,
 };
 const char *pg_state_names[14] = {
    "starting",
    "peering",
    "incomplete",
    "active",
    "stopping",
    "offline",
    "degraded",
    "has_incomplete",
    "has_degraded",
    "has_misplaced",
    "has_unclean",
    "has_invalid",
    "left_on_dead",
 };
--- a/pg_states.h
+++ b/pg_states.h
@ -1,37 +0,0 @@
 // Copyright (c) Vitaliy Filippov, 2019+
 // License: VNPL-1.0 or GNU GPL-2.0+ (see README.md for details)
 #pragma once
 // Placement group states
 // STARTING -> [acquire lock] -> PEERING -> INCOMPLETE|ACTIVE -> STOPPING -> OFFLINE -> [release lock]
 // Exactly one of these:
 #define PG_STARTING (1<<0)
 #define PG_PEERING (1<<1)
 #define PG_INCOMPLETE (1<<2)
 #define PG_ACTIVE (1<<3)
 #define PG_STOPPING (1<<4)
 #define PG_OFFLINE (1<<5)
 // Plus any of these:
 #define PG_DEGRADED (1<<6)
 #define PG_HAS_INCOMPLETE (1<<7)
 #define PG_HAS_DEGRADED (1<<8)
 #define PG_HAS_MISPLACED (1<<9)
 #define PG_HAS_UNCLEAN (1<<10)
 #define PG_HAS_INVALID (1<<11)
 #define PG_LEFT_ON_DEAD (1<<12)
 // Lower bits that represent object role (EC 0/1/2... or always 0 with replication)
 // 12 bits is a safe default that doesn't depend on pg_stripe_size or pg_block_size
 #define STRIPE_MASK ((uint64_t)4096 - 1)
 // OSD object states
 #define OBJ_DEGRADED 0x02
 #define OBJ_INCOMPLETE 0x04
 #define OBJ_MISPLACED 0x08
 #define OBJ_NEEDS_STABLE 0x10000
 #define OBJ_NEEDS_ROLLBACK 0x20000
 extern const int pg_state_bits[];
 extern const char *pg_state_names[];
 extern const int pg_state_bit_count;
--- a/qemu_driver.c
+++ b/qemu_driver.c
@ -1,400 +0,0 @@
 // Copyright (c) Vitaliy Filippov, 2019+
 // License: VNPL-1.0 or GNU GPL-2.0+ (see README.md for details)
 // QEMU block driver
 #define _GNU_SOURCE
 #include "qemu/osdep.h"
 #include "qemu/units.h"
 #include "block/block_int.h"
 #include "block/qdict.h"
 #include "qapi/error.h"
 #include "qapi/qmp/qdict.h"
 #include "qapi/qmp/qerror.h"
 #include "qemu/uri.h"
 #include "qemu/error-report.h"
 #include "qemu/module.h"
 #include "qemu/option.h"
 #include "qemu/cutils.h"
 #include "qemu_proxy.h"
 typedef struct VitastorClient
 {
    void *proxy;
    char *etcd_host;
    char *etcd_prefix;
    uint64_t inode;
    uint64_t pool;
    uint64_t size;
    int readonly;
    QemuMutex mutex;
 } VitastorClient;
 typedef struct VitastorRPC
 {
    BlockDriverState *bs;
    Coroutine *co;
    QEMUIOVector *iov;
    int ret;
    int complete;
 } VitastorRPC;
 static char *qemu_rbd_next_tok(char *src, char delim, char **p)
 {
    char *end;
    *p = NULL;
    for (end = src; *end; ++end)
    {
        if (*end == delim)
            break;
        if (*end == '\\' && end[1] != '\0')
            end++;
    }
    if (*end == delim)
    {
        *p = end + 1;
        *end = '\0';
    }
    return src;
 }
 static void qemu_rbd_unescape(char *src)
 {
    char *p;
    for (p = src; *src; ++src, ++p)
    {
        if (*src == '\\' && src[1] != '\0')
            src++;
        *p = *src;
    }
    *p = '\0';
 }
 // vitastor[:key=value]*
 // vitastor:etcd_host=127.0.0.1:inode=1:pool=1
 static void vitastor_parse_filename(const char *filename, QDict *options, Error **errp)
 {
    const char *start;
    char *p, *buf;
    if (!strstart(filename, "vitastor:", &start))
    {
        error_setg(errp, "File name must start with 'vitastor:'");
        return;
    }
    buf = g_strdup(start);
    p = buf;
    // The following are all key/value pairs
    while (p)
    {
        char *name, *value;
        name = qemu_rbd_next_tok(p, '=', &p);
        if (!p)
        {
            error_setg(errp, "conf option %s has no value", name);
            break;
        }
        qemu_rbd_unescape(name);
        value = qemu_rbd_next_tok(p, ':', &p);
        qemu_rbd_unescape(value);
        if (!strcmp(name, "inode") || !strcmp(name, "pool") || !strcmp(name, "size"))
        {
            unsigned long long num_val;
            if (parse_uint_full(value, &num_val, 0))
            {
                error_setg(errp, "Illegal %s: %s", name, value);
                goto out;
            }
            qdict_put_int(options, name, num_val);
        }
        else
        {
            qdict_put_str(options, name, value);
        }
    }
    if (!qdict_get_try_int(options, "inode", 0))
    {
        error_setg(errp, "inode is missing");
        goto out;
    }
    if (!(qdict_get_try_int(options, "inode", 0) >> (64-POOL_ID_BITS)) &&
        !qdict_get_try_int(options, "pool", 0))
    {
        error_setg(errp, "pool number is missing");
        goto out;
    }
    if (!qdict_get_try_int(options, "size", 0))
    {
        error_setg(errp, "size is missing");
        goto out;
    }
    if (!qdict_get_str(options, "etcd_host"))
    {
        error_setg(errp, "etcd_host is missing");
        goto out;
    }
 out:
    g_free(buf);
    return;
 }
 static int vitastor_file_open(BlockDriverState *bs, QDict *options, int flags, Error **errp)
 {
    VitastorClient *client = bs->opaque;
    int64_t ret = 0;
    client->etcd_host = g_strdup(qdict_get_try_str(options, "etcd_host"));
    client->etcd_prefix = g_strdup(qdict_get_try_str(options, "etcd_prefix"));
    client->inode = qdict_get_int(options, "inode");
    client->pool = qdict_get_int(options, "pool");
    if (client->pool)
        client->inode = (client->inode & ((1l << (64-POOL_ID_BITS)) - 1)) | (client->pool << (64-POOL_ID_BITS));
    client->size = qdict_get_int(options, "size");
    client->readonly = (flags & BDRV_O_RDWR) ? 1 : 0;
    client->proxy = vitastor_proxy_create(bdrv_get_aio_context(bs), client->etcd_host, client->etcd_prefix);
    //client->aio_context = bdrv_get_aio_context(bs);
    bs->total_sectors = client->size / BDRV_SECTOR_SIZE;
    qdict_del(options, "etcd_host");
    qdict_del(options, "etcd_prefix");
    qdict_del(options, "inode");
    qdict_del(options, "pool");
    qdict_del(options, "size");
    qemu_mutex_init(&client->mutex);
    return ret;
 }
 static void vitastor_close(BlockDriverState *bs)
 {
    VitastorClient *client = bs->opaque;
    vitastor_proxy_destroy(client->proxy);
    qemu_mutex_destroy(&client->mutex);
    g_free(client->etcd_host);
    if (client->etcd_prefix)
        g_free(client->etcd_prefix);
 }
 static int vitastor_probe_blocksizes(BlockDriverState *bs, BlockSizes *bsz)
 {
    bsz->phys = 4096;
    bsz->log = 4096;
    return 0;
 }
 static int coroutine_fn vitastor_co_create_opts(
 #if QEMU_VERSION_MAJOR >= 4
    BlockDriver *drv,
 #endif
    const char *url, QemuOpts *opts, Error **errp)
 {
    QDict *options;
    int ret;
    options = qdict_new();
    vitastor_parse_filename(url, options, errp);
    if (*errp)
    {
        ret = -1;
        goto out;
    }
    // inodes don't require creation in Vitastor. FIXME: They will when there will be some metadata
    ret = 0;
 out:
    qobject_unref(options);
    return ret;
 }
 static int coroutine_fn vitastor_co_truncate(BlockDriverState *bs, int64_t offset,
 #if QEMU_VERSION_MAJOR >= 4
    bool exact,
 #endif
    PreallocMode prealloc, Error **errp)
 {
    VitastorClient *client = bs->opaque;
    if (prealloc != PREALLOC_MODE_OFF)
    {
        error_setg(errp, "Unsupported preallocation mode '%s'", PreallocMode_str(prealloc));
        return -ENOTSUP;
    }
    // TODO: Resize inode to <offset> bytes
    client->size = offset / BDRV_SECTOR_SIZE;
    return 0;
 }
 static int vitastor_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
 {
    bdi->cluster_size = 4096;
    return 0;
 }
 static int64_t vitastor_getlength(BlockDriverState *bs)
 {
    VitastorClient *client = bs->opaque;
    return client->size;
 }
 static void vitastor_refresh_limits(BlockDriverState *bs, Error **errp)
 {
    bs->bl.request_alignment = 4096;
    bs->bl.min_mem_alignment = 4096;
    bs->bl.opt_mem_alignment = 4096;
 }
 static int64_t vitastor_get_allocated_file_size(BlockDriverState *bs)
 {
    return 0;
 }
 static void vitastor_co_init_task(BlockDriverState *bs, VitastorRPC *task)
 {
    *task = (VitastorRPC) {
        .co     = qemu_coroutine_self(),
        .bs     = bs,
    };
 }
 static void vitastor_co_generic_bh_cb(int retval, void *opaque)
 {
    VitastorRPC *task = opaque;
    task->ret = retval;
    task->complete = 1;
    if (qemu_coroutine_self() != task->co)
    {
        aio_co_wake(task->co);
    }
 }
 static int coroutine_fn vitastor_co_preadv(BlockDriverState *bs, uint64_t offset, uint64_t bytes, QEMUIOVector *iov, int flags)
 {
    VitastorClient *client = bs->opaque;
    VitastorRPC task;
    vitastor_co_init_task(bs, &task);
    task.iov = iov;
    qemu_mutex_lock(&client->mutex);
    vitastor_proxy_rw(0, client->proxy, client->inode, offset, bytes, iov->iov, iov->niov, vitastor_co_generic_bh_cb, &task);
    qemu_mutex_unlock(&client->mutex);
    while (!task.complete)
    {
        qemu_coroutine_yield();
    }
    return task.ret;
 }
 static int coroutine_fn vitastor_co_pwritev(BlockDriverState *bs, uint64_t offset, uint64_t bytes, QEMUIOVector *iov, int flags)
 {
    VitastorClient *client = bs->opaque;
    VitastorRPC task;
    vitastor_co_init_task(bs, &task);
    task.iov = iov;
    qemu_mutex_lock(&client->mutex);
    vitastor_proxy_rw(1, client->proxy, client->inode, offset, bytes, iov->iov, iov->niov, vitastor_co_generic_bh_cb, &task);
    qemu_mutex_unlock(&client->mutex);
    while (!task.complete)
    {
        qemu_coroutine_yield();
    }
    return task.ret;
 }
 static int coroutine_fn vitastor_co_flush(BlockDriverState *bs)
 {
    VitastorClient *client = bs->opaque;
    VitastorRPC task;
    vitastor_co_init_task(bs, &task);
    qemu_mutex_lock(&client->mutex);
    vitastor_proxy_sync(client->proxy, vitastor_co_generic_bh_cb, &task);
    qemu_mutex_unlock(&client->mutex);
    while (!task.complete)
    {
        qemu_coroutine_yield();
    }
    return task.ret;
 }
 static QemuOptsList vitastor_create_opts = {
    .name = "vitastor-create-opts",
    .head = QTAILQ_HEAD_INITIALIZER(vitastor_create_opts.head),
    .desc = {
        {
            .name = BLOCK_OPT_SIZE,
            .type = QEMU_OPT_SIZE,
            .help = "Virtual disk size"
        },
        { /* end of list */ }
    }
 };
 static const char *vitastor_strong_runtime_opts[] = {
    "inode",
    "pool",
    "etcd_host",
    "etcd_prefix",
    NULL
 };
 static BlockDriver bdrv_vitastor = {
    .format_name                    = "vitastor",
    .protocol_name                  = "vitastor",
    .instance_size                  = sizeof(VitastorClient),
    .bdrv_parse_filename            = vitastor_parse_filename,
    .bdrv_has_zero_init             = bdrv_has_zero_init_1,
 #if QEMU_VERSION_MAJOR >= 4
    .bdrv_has_zero_init_truncate    = bdrv_has_zero_init_1,
 #endif
    .bdrv_get_info                  = vitastor_get_info,
    .bdrv_getlength                 = vitastor_getlength,
    .bdrv_probe_blocksizes          = vitastor_probe_blocksizes,
    .bdrv_refresh_limits            = vitastor_refresh_limits,
    // FIXME: Implement it along with per-inode statistics
    //.bdrv_get_allocated_file_size   = vitastor_get_allocated_file_size,
    .bdrv_file_open                 = vitastor_file_open,
    .bdrv_close                     = vitastor_close,
    // Option list for the create operation
    .create_opts                    = &vitastor_create_opts,
    // For qmp_blockdev_create(), used by the qemu monitor / QAPI
    // Requires patching QAPI IDL, thus unimplemented
    //.bdrv_co_create                 = vitastor_co_create,
    // For bdrv_create(), used by qemu-img
    .bdrv_co_create_opts            = vitastor_co_create_opts,
    .bdrv_co_truncate               = vitastor_co_truncate,
    .bdrv_co_preadv                 = vitastor_co_preadv,
    .bdrv_co_pwritev                = vitastor_co_pwritev,
    .bdrv_co_flush_to_disk          = vitastor_co_flush,
 #if QEMU_VERSION_MAJOR >= 4
    .strong_runtime_opts            = vitastor_strong_runtime_opts,
 #endif
 };
 static void vitastor_block_init(void)
 {
    bdrv_register(&bdrv_vitastor);
 }
 block_init(vitastor_block_init);
--- a/qemu_proxy.cpp
+++ b/qemu_proxy.cpp
@ -1,130 +0,0 @@
 // Copyright (c) Vitaliy Filippov, 2019+
 // License: VNPL-1.0 or GNU GPL-2.0+ (see README.md for details)
 // C-C++ proxy for the QEMU driver
 // (QEMU headers don't compile with g++)
 #include <sys/epoll.h>
 #include "cluster_client.h"
 typedef void* AioContext;
 #include "qemu_proxy.h"
 extern "C"
 {
    // QEMU
    typedef void IOHandler(void *opaque);
    void aio_set_fd_handler(AioContext *ctx, int fd, int is_external, IOHandler *fd_read, IOHandler *fd_write, void *poll_fn, void *opaque);
 }
 struct QemuProxyData
 {
    int fd;
    std::function<void(int, int)> callback;
 };
 class QemuProxy
 {
    std::map<int, QemuProxyData> handlers;
 public:
    timerfd_manager_t *tfd;
    cluster_client_t *cli;
    AioContext *ctx;
    QemuProxy(AioContext *ctx, const char *etcd_host, const char *etcd_prefix)
    {
        this->ctx = ctx;
        json11::Json cfg = json11::Json::object {
            { "etcd_address", std::string(etcd_host) },
            { "etcd_prefix", std::string(etcd_prefix ? etcd_prefix : "/vitastor") },
        };
        tfd = new timerfd_manager_t([this](int fd, bool wr, std::function<void(int, int)> callback) { set_fd_handler(fd, wr, callback); });
        cli = new cluster_client_t(NULL, tfd, cfg);
    }
    ~QemuProxy()
    {
        cli->stop();
        delete cli;
        delete tfd;
    }
    void set_fd_handler(int fd, bool wr, std::function<void(int, int)> callback)
    {
        if (callback != NULL)
        {
            handlers[fd] = { .fd = fd, .callback = callback };
            aio_set_fd_handler(ctx, fd, false, &QemuProxy::read_handler, wr ? &QemuProxy::write_handler : NULL, NULL, &handlers[fd]);
        }
        else
        {
            handlers.erase(fd);
            aio_set_fd_handler(ctx, fd, false, NULL, NULL, NULL, NULL);
        }
    }
    static void read_handler(void *opaque)
    {
        QemuProxyData *data = (QemuProxyData *)opaque;
        data->callback(data->fd, EPOLLIN);
    }
    static void write_handler(void *opaque)
    {
        QemuProxyData *data = (QemuProxyData *)opaque;
        data->callback(data->fd, EPOLLOUT);
    }
 };
 extern "C" {
 void* vitastor_proxy_create(AioContext *ctx, const char *etcd_host, const char *etcd_prefix)
 {
    QemuProxy *p = new QemuProxy(ctx, etcd_host, etcd_prefix);
    return p;
 }
 void vitastor_proxy_destroy(void *client)
 {
    QemuProxy *p = (QemuProxy*)client;
    delete p;
 }
 void vitastor_proxy_rw(int write, void *client, uint64_t inode, uint64_t offset, uint64_t len,
    iovec *iov, int iovcnt, VitastorIOHandler cb, void *opaque)
 {
    QemuProxy *p = (QemuProxy*)client;
    cluster_op_t *op = new cluster_op_t;
    op->opcode = write ? OSD_OP_WRITE : OSD_OP_READ;
    op->inode = inode;
    op->offset = offset;
    op->len = len;
    for (int i = 0; i < iovcnt; i++)
    {
        op->iov.push_back(iov[i].iov_base, iov[i].iov_len);
    }
    op->callback = [cb, opaque](cluster_op_t *op)
    {
        cb(op->retval, opaque);
        delete op;
    };
    p->cli->execute(op);
 }
 void vitastor_proxy_sync(void *client, VitastorIOHandler cb, void *opaque)
 {
    QemuProxy *p = (QemuProxy*)client;
    cluster_op_t *op = new cluster_op_t;
    op->opcode = OSD_OP_SYNC;
    op->callback = [cb, opaque](cluster_op_t *op)
    {
        cb(op->retval, opaque);
        delete op;
    };
    p->cli->execute(op);
 }
 }
--- a/qemu_proxy.h
+++ b/qemu_proxy.h
@ -1,29 +0,0 @@
 // Copyright (c) Vitaliy Filippov, 2019+
 // License: VNPL-1.0 or GNU GPL-2.0+ (see README.md for details)
 #ifndef VITASTOR_QEMU_PROXY_H
 #define VITASTOR_QEMU_PROXY_H
 #ifndef POOL_ID_BITS
 #define POOL_ID_BITS 16
 #endif
 #include <stdint.h>
 #include <sys/uio.h>
 #ifdef __cplusplus
 extern "C" {
 #endif
 // Our exports
 typedef void VitastorIOHandler(int retval, void *opaque);
 void* vitastor_proxy_create(AioContext *ctx, const char *etcd_host, const char *etcd_prefix);
 void vitastor_proxy_destroy(void *client);
 void vitastor_proxy_rw(int write, void *client, uint64_t inode, uint64_t offset, uint64_t len,
    struct iovec *iov, int iovcnt, VitastorIOHandler cb, void *opaque);
 void vitastor_proxy_sync(void *client, VitastorIOHandler cb, void *opaque);
 #ifdef __cplusplus
 }
 #endif
 #endif
--- a/ringloop.cpp
+++ b/ringloop.cpp
@ -1,17 +1,19 @@
-// Copyright (c) Vitaliy Filippov, 2019+
+#include <set>
 // License: VNPL-1.0 or GNU GPL-2.0+ (see README.md for details)
 #include "ringloop.h"
 ring_loop_t::ring_loop_t(int qd)
 {
-    int ret = io_uring_queue_init(qd, &ring, 0);
+    io_uring_params params = { 0 };
    params.flags = IORING_SETUP_SQPOLL;
    params.sq_thread_idle = 10;
    int ret = io_uring_queue_init_params(qd, &ring, &params);
    if (ret < 0)
    {
        throw std::runtime_error(std::string("io_uring_queue_init: ") + strerror(-ret));
    }
-    free_ring_data_ptr = *ring.cq.kring_entries;
+    ring_data_total = free_ring_data_ptr = *ring.cq.kring_entries;
-    ring_datas = (struct ring_data_t*)malloc(sizeof(ring_data_t) * free_ring_data_ptr);
+    ring_datas = (ring_data_t*)malloc(sizeof(ring_data_t) * free_ring_data_ptr);
    free_ring_data = (int*)malloc(sizeof(int) * free_ring_data_ptr);
    if (!ring_datas || !free_ring_data)
    {
@ -19,9 +21,9 @@ ring_loop_t::ring_loop_t(int qd)
    }
    for (int i = 0; i < free_ring_data_ptr; i++)
    {
        ring_datas[i] = { 0 };
        free_ring_data[i] = i;
    }
    wait_sqe_id = 1;
 }
 ring_loop_t::~ring_loop_t()
@ -31,10 +33,110 @@ ring_loop_t::~ring_loop_t()
    io_uring_queue_exit(&ring);
 }
-void ring_loop_t::register_consumer(ring_consumer_t *consumer)
+void ring_loop_t::drain_events(void *completions_ptr)
 {
-    unregister_consumer(consumer);
+    std::set<ring_data_t*> & completions = *((std::set<ring_data_t*> *)completions_ptr);
    if (free_ring_data_ptr < ring_data_total)
    {
        // Try to cancel requests that are allowed to be canceled by the caller (epoll, timerfd and similar)
        for (int i = 0; i < ring_data_total; i++)
        {
            if (ring_datas[i].allow_cancel)
            {
                // allow_cancel may only be true while the operation is inflight
                io_uring_sqe *sqe = get_sqe();
                if (!sqe)
                {
                    throw std::runtime_error("can't get SQE to cancel operation");
                }
                ring_data_t *data = (ring_data_t*)sqe->user_data;
                data->callback = NULL;
                ring_datas[i].res = -ECANCELED;
                my_uring_prep_cancel(sqe, &ring_datas[i], 0);
                // It seems (FIXME) cancel operations don't always get completions
                completions.insert(data);
            }
        }
        if (completions.size() > 0)
        {
            submit();
        }
    }
    int inflight = ring_data_total - free_ring_data_ptr;
    while (completions.size() < inflight)
    {
        io_uring_cqe *cqe;
        while (!io_uring_peek_cqe(&ring, &cqe))
        {
            ring_data_t *d = (ring_data_t*)cqe->user_data;
            d->res = cqe->res;
            d->allow_cancel = false;
            completions.insert(d);
            io_uring_cqe_seen(&ring, cqe);
        }
        if (completions.size() < inflight)
        {
            wait();
        }
    }
 }
 void ring_loop_t::run_completions(void *completions_ptr)
 {
    std::set<ring_data_t*> & completions = *((std::set<ring_data_t*> *)completions_ptr);
    // Call event callbacks
    for (ring_data_t *d: completions)
    {
        free_ring_data[free_ring_data_ptr++] = d - ring_datas;
        if (d->callback)
            d->callback(d);
    }
 }
 int ring_loop_t::register_fd(int fd)
 {
    std::set<ring_data_t*> completions;
    drain_events((void*)&completions);
    // Modify registered files
    int idx = reg_fds.size();
    reg_fds.push_back(fd);
    if (registered)
    {
        io_uring_unregister_files(&ring);
    }
    int ret = io_uring_register_files(&ring, reg_fds.data(), reg_fds.size());
    if (ret != 0)
    {
        throw std::runtime_error(std::string("io_uring_register_files_update: ") + strerror(-ret));
    }
    registered = 1;
    run_completions((void*)&completions);
    return idx;
 }
 void ring_loop_t::unregister_fd(int fd_index)
 {
    std::set<ring_data_t*> completions;
    drain_events((void*)&completions);
    // Modify registered files
    reg_fds.erase(reg_fds.begin()+fd_index, reg_fds.begin()+fd_index+1);
    if (registered)
    {
        io_uring_unregister_files(&ring);
    }
    int ret = io_uring_register_files(&ring, reg_fds.data(), reg_fds.size());
    if (ret != 0)
    {
        throw std::runtime_error(std::string("io_uring_register_files_update: ") + strerror(-ret));
    }
    run_completions((void*)&completions);
 }
 int ring_loop_t::register_consumer(ring_consumer_t & consumer)
 {
    consumer.number = consumers.size();
    consumers.push_back(consumer);
    return consumer.number;
 }
 void ring_loop_t::wakeup()
@ -42,43 +144,34 @@ void ring_loop_t::wakeup()
    loop_again = true;
 }
-void ring_loop_t::unregister_consumer(ring_consumer_t *consumer)
+void ring_loop_t::unregister_consumer(ring_consumer_t & consumer)
 {
-    for (int i = 0; i < consumers.size(); i++)
+    if (consumer.number >= 0 && consumer.number < consumers.size())
    {
-        if (consumers[i] == consumer)
+        consumers[consumer.number].loop = NULL;
-        {
+        consumer.number = -1;
            consumers.erase(consumers.begin()+i, consumers.begin()+i+1);
            break;
        }
    }
 }
 void ring_loop_t::loop()
 {
-    struct io_uring_cqe *cqe;
+    io_uring_cqe *cqe;
    while (!io_uring_peek_cqe(&ring, &cqe))
    {
-        struct ring_data_t *d = (struct ring_data_t*)cqe->user_data;
+        ring_data_t *d = (ring_data_t*)cqe->user_data;
-        if (d->callback)
+        d->res = cqe->res;
-        {
+        d->allow_cancel = false;
            d->res = cqe->res;
            d->callback(d);
        }
        free_ring_data[free_ring_data_ptr++] = d - ring_datas;
        io_uring_cqe_seen(&ring, cqe);
-    }
+        free_ring_data[free_ring_data_ptr++] = d - ring_datas;
-    while (get_sqe_queue.size() > 0)
+        if (d->callback)
-    {
+            d->callback(d);
        (get_sqe_queue[0].second)();
        get_sqe_queue.erase(get_sqe_queue.begin());
    }
    do
    {
        loop_again = false;
        for (int i = 0; i < consumers.size(); i++)
        {
-            consumers[i]->loop();
+            consumers[i].loop();
        }
    } while (loop_again);
 }
--- a/ringloop.h
+++ b/ringloop.h
@ -1,6 +1,3 @@
 // Copyright (c) Vitaliy Filippov, 2019+
 // License: VNPL-1.0 or GNU GPL-2.0+ (see README.md for details)
 #pragma once
 #ifndef _LARGEFILE64_SOURCE
@ -110,54 +107,52 @@ static inline void my_uring_prep_cancel(struct io_uring_sqe *sqe, void *user_dat
 struct ring_data_t
 {
    struct iovec iov; // for single-entry read/write operations
    bool allow_cancel;
    int res;
    std::function<void(ring_data_t*)> callback;
 };
 struct ring_consumer_t
 {
    int number;
    std::function<void(void)> loop;
 };
 class ring_loop_t
 {
-    std::vector<std::pair<int,std::function<void()>>> get_sqe_queue;
+    std::vector<ring_consumer_t> consumers;
    std::vector<ring_consumer_t*> consumers;
    struct ring_data_t *ring_datas;
    int *free_ring_data;
-    int wait_sqe_id;
+    unsigned free_ring_data_ptr, ring_data_total;
    unsigned free_ring_data_ptr;
    bool loop_again;
    struct io_uring ring;
    int registered = 0;
    std::vector<int> reg_fds;
    void drain_events(void *completions_ptr);
    void run_completions(void *completions_ptr);
 public:
    ring_loop_t(int qd);
    ~ring_loop_t();
-    void register_consumer(ring_consumer_t *consumer);
+    int register_consumer(ring_consumer_t & consumer);
-    void unregister_consumer(ring_consumer_t *consumer);
+    void unregister_consumer(ring_consumer_t & consumer);
    int register_fd(int fd);
    void unregister_fd(int fd_index);
    inline struct io_uring_sqe* get_sqe()
    {
        if (free_ring_data_ptr == 0)
        {
            return NULL;
        }
        struct io_uring_sqe* sqe = io_uring_get_sqe(&ring);
        if (sqe)
            io_uring_sqe_set_data(sqe, ring_datas + free_ring_data[--free_ring_data_ptr]);
        return sqe;
    }
    inline int wait_sqe(std::function<void()> cb)
    {
        get_sqe_queue.push_back({ wait_sqe_id, cb });
        return wait_sqe_id++;
    }
    inline void cancel_wait_sqe(int wait_id)
    {
        for (int i = 0; i < get_sqe_queue.size(); i++)
        {
-            if (get_sqe_queue[i].first == wait_id)
+            ring_data_t *data = ring_datas + free_ring_data[--free_ring_data_ptr];
-            {
+            io_uring_sqe_set_data(sqe, data);
                get_sqe_queue.erase(get_sqe_queue.begin()+i, get_sqe_queue.begin()+i+1);
            }
        }
        return sqe;
    }
    inline int submit()
    {
@ -172,7 +167,7 @@ public:
    {
        return free_ring_data_ptr;
    }
-    inline bool has_work()
+    inline bool get_loop_again()
    {
        return loop_again;
    }
--- a/rw_blocking.cpp
+++ b/rw_blocking.cpp
@ -1,6 +1,3 @@
 // Copyright (c) Vitaliy Filippov, 2019+
 // License: VNPL-1.0 or GNU GPL-2.0+ (see README.md for details)
 #include <errno.h>
 #include <stdlib.h>
 #include <stdio.h>
@ -54,40 +51,6 @@ int write_blocking(int fd, void *write_buf, size_t remaining)
    return done;
 }
 int readv_blocking(int fd, iovec *iov, int iovcnt)
 {
    int v = 0;
    int done = 0;
    while (v < iovcnt)
    {
        ssize_t r = readv(fd, iov, iovcnt);
        if (r < 0)
        {
            if (errno != EAGAIN && errno != EPIPE)
            {
                perror("writev");
                exit(1);
            }
            continue;
        }
        while (v < iovcnt)
        {
            if (iov[v].iov_len > r)
            {
                iov[v].iov_len -= r;
                iov[v].iov_base += r;
                break;
            }
            else
            {
                v++;
            }
        }
        done += r;
    }
    return done;
 }
 int writev_blocking(int fd, iovec *iov, int iovcnt)
 {
    int v = 0;
--- a/rw_blocking.h
+++ b/rw_blocking.h
@ -1,6 +1,3 @@
 // Copyright (c) Vitaliy Filippov, 2019+
 // License: VNPL-1.0 or GNU GPL-2.0+ (see README.md for details)
 #pragma once
 #include <unistd.h>
@ -8,5 +5,4 @@
 int read_blocking(int fd, void *read_buf, size_t remaining);
 int write_blocking(int fd, void *write_buf, size_t remaining);
 int readv_blocking(int fd, iovec *iov, int iovcnt);
 int writev_blocking(int fd, iovec *iov, int iovcnt);
--- a/stub_bench.cpp
+++ b/stub_bench.cpp
@ -1,6 +1,3 @@
 // Copyright (c) Vitaliy Filippov, 2019+
 // License: VNPL-1.0 or GNU GPL-2.0+ (see README.md for details)
 /**
 * Stub benchmarker
 */
@ -28,37 +25,20 @@ int connect_stub(const char *server_address, int server_port);
 void run_bench(int peer_fd);
 static uint64_t read_sum = 0, read_count = 0;
 static uint64_t write_sum = 0, write_count = 0;
 static uint64_t sync_sum = 0, sync_count = 0;
 void handle_sigint(int sig)
 {
-    printf("4k randread: %lu us avg\n", read_count ? read_sum/read_count : 0);
+    printf("4k randwrite: %lu us avg\n", write_sum/write_count);
-    printf("4k randwrite: %lu us avg\n", write_count ? write_sum/write_count : 0);
+    printf("sync: %lu us avg\n", sync_sum/sync_count);
    printf("sync: %lu us avg\n", sync_count ? sync_sum/sync_count : 0);
    exit(0);
 }
 int main(int narg, char *args[])
 {
    if (narg < 2)
    {
        printf("USAGE: %s SERVER_IP [PORT]\n", args[0]);
        return 1;
    }
    int port = 11203;
    if (narg >= 3)
    {
        port = atoi(args[2]);
        if (port <= 0 || port >= 65536)
        {
            printf("Bad port number\n");
            return 1;
        }
    }
    signal(SIGINT, handle_sigint);
-    int peer_fd = connect_stub(args[1], port);
+    int peer_fd = connect_stub("127.0.0.1", 11203);
    run_bench(peer_fd);
    close(peer_fd);
    return 0;
@ -118,41 +98,14 @@ void run_bench(int peer_fd)
    osd_any_reply_t reply;
    void *buf = NULL;
    int r;
    iovec iov[2];
    timespec tv_begin, tv_end;
    clock_gettime(CLOCK_REALTIME, &tv_begin);
    while (1)
    {
        // read
        op.hdr.magic = SECONDARY_OSD_OP_MAGIC;
        op.hdr.id = 1;
        op.hdr.opcode = OSD_OP_SEC_READ;
        op.sec_rw.oid.inode = 3;
        op.sec_rw.oid.stripe = (rand() << 17) % (1 << 29); // 512 MB
        op.sec_rw.version = 0;
        op.sec_rw.len = 4096;
        op.sec_rw.offset = (rand() * op.sec_rw.len) % (1 << 17);
        r = write_blocking(peer_fd, op.buf, OSD_PACKET_SIZE) == OSD_PACKET_SIZE;
        if (!r)
            break;
        buf = malloc(op.sec_rw.len);
        iov[0] = { reply.buf, OSD_PACKET_SIZE };
        iov[1] = { buf, op.sec_rw.len };
        r = readv_blocking(peer_fd, iov, 2) == (OSD_PACKET_SIZE + op.sec_rw.len);
        free(buf);
        if (!r || !check_reply(OSD_PACKET_SIZE, op, reply, op.sec_rw.len))
            break;
        clock_gettime(CLOCK_REALTIME, &tv_end);
        read_count++;
        read_sum += (
            (tv_end.tv_sec - tv_begin.tv_sec)*1000000 +
            tv_end.tv_nsec/1000 - tv_begin.tv_nsec/1000
        );
        tv_begin = tv_end;
        // write
        op.hdr.magic = SECONDARY_OSD_OP_MAGIC;
        op.hdr.id = 1;
-        op.hdr.opcode = OSD_OP_SEC_WRITE;
+        op.hdr.opcode = OSD_OP_SECONDARY_WRITE;
        op.sec_rw.oid.inode = 3;
        op.sec_rw.oid.stripe = (rand() << 17) % (1 << 29); // 512 MB
        op.sec_rw.version = 0;
@ -160,9 +113,9 @@ void run_bench(int peer_fd)
        op.sec_rw.offset = (rand() * op.sec_rw.len) % (1 << 17);
        buf = malloc(op.sec_rw.len);
        memset(buf, rand() % 255, op.sec_rw.len);
-        iov[0] = { op.buf, OSD_PACKET_SIZE };
+        r = write_blocking(peer_fd, op.buf, OSD_PACKET_SIZE) == OSD_PACKET_SIZE;
-        iov[1] = { buf, op.sec_rw.len };
+        if (r)
-        r = writev_blocking(peer_fd, iov, 2) == (OSD_PACKET_SIZE + op.sec_rw.len);
+            r = write_blocking(peer_fd, buf, op.sec_rw.len) == op.sec_rw.len;
        free(buf);
        if (!r)
            break;
@ -175,7 +128,6 @@ void run_bench(int peer_fd)
            (tv_end.tv_sec - tv_begin.tv_sec)*1000000 +
            tv_end.tv_nsec/1000 - tv_begin.tv_nsec/1000
        );
        tv_begin = tv_end;
        // sync/stab
        op.hdr.magic = SECONDARY_OSD_OP_MAGIC;
        op.hdr.id = 1;
@ -186,12 +138,11 @@ void run_bench(int peer_fd)
        r = read_blocking(peer_fd, reply.buf, OSD_PACKET_SIZE);
        if (!check_reply(r, op, reply, 0))
            break;
-        clock_gettime(CLOCK_REALTIME, &tv_end);
+        clock_gettime(CLOCK_REALTIME, &tv_begin);
        sync_count++;
        sync_sum += (
-            (tv_end.tv_sec - tv_begin.tv_sec)*1000000 +
+            (tv_begin.tv_sec - tv_end.tv_sec)*1000000 +
-            tv_end.tv_nsec/1000 - tv_begin.tv_nsec/1000
+            tv_begin.tv_nsec/1000 - tv_end.tv_nsec/1000
        );
        tv_begin = tv_end;
    }
 }
--- a/stub_osd.cpp
+++ b/stub_osd.cpp
@ -1,6 +1,3 @@
 // Copyright (c) Vitaliy Filippov, 2019+
 // License: VNPL-1.0 or GNU GPL-2.0+ (see README.md for details)
 /**
 * Stub "OSD" to test & compare network performance with sync read/write and io_uring
 *
@ -133,7 +130,7 @@ void run_stub(int peer_fd)
        reply.hdr.magic = SECONDARY_OSD_REPLY_MAGIC;
        reply.hdr.id = op.hdr.id;
        reply.hdr.opcode = op.hdr.opcode;
-        if (op.hdr.opcode == OSD_OP_SEC_READ)
+        if (op.hdr.opcode == OSD_OP_SECONDARY_READ)
        {
            reply.hdr.retval = op.sec_rw.len;
            buf = malloc(op.sec_rw.len);
@ -144,7 +141,7 @@ void run_stub(int peer_fd)
            if (r < op.sec_rw.len)
                break;
        }
-        else if (op.hdr.opcode == OSD_OP_SEC_WRITE || op.hdr.opcode == OSD_OP_SEC_WRITE_STABLE)
+        else if (op.hdr.opcode == OSD_OP_SECONDARY_WRITE)
        {
            buf = malloc(op.sec_rw.len);
            r = read_blocking(peer_fd, buf, op.sec_rw.len);
--- a/stub_uring_osd.cpp
+++ b/stub_uring_osd.cpp
@ -1,131 +0,0 @@
 // Copyright (c) Vitaliy Filippov, 2019+
 // License: VNPL-1.0 or GNU GPL-2.0+ (see README.md for details)
 /**
 * Stub "OSD" implemented on top of osd_messenger to test & compare
 * network performance with sync read/write and io_uring
 */
 #include <sys/types.h>
 #include <sys/socket.h>
 #include <netinet/in.h>
 #include <netinet/tcp.h>
 #include <arpa/inet.h>
 #include <string.h>
 #include <stdio.h>
 #include <unistd.h>
 #include <fcntl.h>
 #include <errno.h>
 #include <stdlib.h>
 #include <stdexcept>
 #include "ringloop.h"
 #include "epoll_manager.h"
 #include "messenger.h"
 int bind_stub(const char *bind_address, int bind_port);
 void stub_exec_op(osd_messenger_t *msgr, osd_op_t *op);
 int main(int narg, char *args[])
 {
    ring_consumer_t looper;
    ring_loop_t *ringloop = new ring_loop_t(512);
    epoll_manager_t *epmgr = new epoll_manager_t(ringloop);
    osd_messenger_t *msgr = new osd_messenger_t();
    msgr->osd_num = 1351;
    msgr->tfd = epmgr->tfd;
    msgr->ringloop = ringloop;
    msgr->repeer_pgs = [](osd_num_t) {};
    msgr->exec_op = [msgr](osd_op_t *op) { stub_exec_op(msgr, op); };
    // Accept new connections
    int listen_fd = bind_stub("0.0.0.0", 11203);
    epmgr->set_fd_handler(listen_fd, false, [listen_fd, msgr](int fd, int events)
    {
        msgr->accept_connections(listen_fd);
    });
    looper.loop = [msgr, ringloop]()
    {
        msgr->read_requests();
        msgr->send_replies();
        ringloop->submit();
    };
    ringloop->register_consumer(&looper);
    printf("stub_uring_osd: waiting for clients\n");
    while (true)
    {
        ringloop->loop();
        ringloop->wait();
    }
    delete msgr;
    delete epmgr;
    delete ringloop;
    return 0;
 }
 int bind_stub(const char *bind_address, int bind_port)
 {
    int listen_backlog = 128;
    int listen_fd = socket(AF_INET, SOCK_STREAM, 0);
    if (listen_fd < 0)
    {
        throw std::runtime_error(std::string("socket: ") + strerror(errno));
    }
    int enable = 1;
    setsockopt(listen_fd, SOL_SOCKET, SO_REUSEADDR, &enable, sizeof(enable));
    sockaddr_in addr;
    int r;
    if ((r = inet_pton(AF_INET, bind_address, &addr.sin_addr)) != 1)
    {
        close(listen_fd);
        throw std::runtime_error("bind address "+std::string(bind_address)+(r == 0 ? " is not valid" : ": no ipv4 support"));
    }
    addr.sin_family = AF_INET;
    addr.sin_port = htons(bind_port);
    if (bind(listen_fd, (sockaddr*)&addr, sizeof(addr)) < 0)
    {
        close(listen_fd);
        throw std::runtime_error(std::string("bind: ") + strerror(errno));
    }
    if (listen(listen_fd, listen_backlog) < 0)
    {
        close(listen_fd);
        throw std::runtime_error(std::string("listen: ") + strerror(errno));
    }
    fcntl(listen_fd, F_SETFL, fcntl(listen_fd, F_GETFL, 0) | O_NONBLOCK);
    return listen_fd;
 }
 void stub_exec_op(osd_messenger_t *msgr, osd_op_t *op)
 {
    op->reply.hdr.magic = SECONDARY_OSD_REPLY_MAGIC;
    op->reply.hdr.id = op->req.hdr.id;
    op->reply.hdr.opcode = op->req.hdr.opcode;
    if (op->req.hdr.opcode == OSD_OP_SEC_READ)
    {
        op->reply.hdr.retval = op->req.sec_rw.len;
        op->buf = malloc(op->req.sec_rw.len);
        op->iov.push_back(op->buf, op->req.sec_rw.len);
    }
    else if (op->req.hdr.opcode == OSD_OP_SEC_WRITE || op->req.hdr.opcode == OSD_OP_SEC_WRITE_STABLE)
    {
        op->reply.hdr.retval = op->req.sec_rw.len;
    }
    else if (op->req.hdr.opcode == OSD_OP_TEST_SYNC_STAB_ALL)
    {
        op->reply.hdr.retval = 0;
    }
    else
    {
        printf("client %d: unsupported stub opcode: %lu\n", op->peer_fd, op->req.hdr.opcode);
        op->reply.hdr.retval = -EINVAL;
    }
    msgr->outbox_push(op);
 }
--- a/test.cpp
+++ b/test.cpp
@ -1,6 +1,3 @@
 // Copyright (c) Vitaliy Filippov, 2019+
 // License: VNPL-1.0 (see README.md for details)
 #define _LARGEFILE64_SOURCE
 #include <sys/types.h>
 #include <sys/ioctl.h>
@ -16,7 +13,6 @@
 #include <assert.h>
 #include <stdio.h>
 #include <liburing.h>
 #include <math.h>
 #include <sys/socket.h>
 #include <sys/epoll.h>
@ -65,6 +61,24 @@ static void test_write(struct io_uring *ring, int fd)
    free(buf);
 }
 class obj_ver_hash
 {
 public:
    size_t operator()(const obj_ver_id &s) const
    {
        size_t seed = 0;
        spp::hash_combine(seed, s.oid.inode);
        spp::hash_combine(seed, s.oid.stripe);
        spp::hash_combine(seed, s.version);
        return seed;
    }
 };
 inline bool operator == (const obj_ver_id & a, const obj_ver_id & b)
 {
    return a.oid == b.oid && a.version == b.version;
 }
 int main00(int argc, char *argv[])
 {
    // queue with random removal: vector is best :D
@ -156,9 +170,9 @@ int main0(int argc, char *argv[])
    // btree_map 5M entries monotone -> 0.458s, random -> 5.429s
    // absl::btree_map 5M entries random -> 5.09s
    // sparse_hash_map 5M entries -> 2.193s, random -> 2.586s
-    btree::btree_map<obj_ver_id, dirty_entry> dirty_db;
+    //btree::btree_map<obj_ver_id, dirty_entry> dirty_db;
    //std::map<obj_ver_id, dirty_entry> dirty_db;
-    //spp::sparse_hash_map<obj_ver_id, dirty_entry, obj_ver_hash> dirty_db;
+    spp::sparse_hash_map<obj_ver_id, dirty_entry, obj_ver_hash> dirty_db;
    for (int i = 0; i < 5000000; i++)
    {
        dirty_db[(obj_ver_id){
@ -168,7 +182,7 @@ int main0(int argc, char *argv[])
            },
            .version = 1,
        }] = (dirty_entry){
-            .state = ST_D_SYNCED,
+            .state = ST_D_META_SYNCED,
            .flags = 0,
            .location = (uint64_t)i << 17,
            .offset = 0,
@ -323,253 +337,87 @@ int main04(int argc, char *argv[])
    return 0;
 }
-uint64_t jumphash(uint64_t key, int count)
+int main05(int argc, char *argv[])
 {
-    uint64_t b = 0;
+    // FIXME extract this into a test
-    uint64_t seed = key;
+    pg_t pg = {
-    for (int j = 1; j < count; j++)
+        .state = PG_PEERING,
        .pg_num = 1,
        .target_set = { 1, 2, 3 },
        .cur_set = { 1, 2, 3 },
        .peering_state = new pg_peering_state_t(),
    };
    for (uint64_t osd_num = 1; osd_num <= 3; osd_num++)
    {
-        seed = 2862933555777941757ull*seed + 3037000493ull; // LCPRNG
+        pg_list_result_t r = {
-        if (seed < (UINT64_MAX / (j+1)))
+            .buf = (obj_ver_id*)malloc(sizeof(obj_ver_id) * 1024*1024*8),
            .total_count = 1024*1024*8,
            .stable_count = (uint64_t)(1024*1024*8 - (osd_num == 1 ? 10 : 0)),
        };
        for (uint64_t i = 0; i < r.total_count; i++)
        {
-            b = j;
+            r.buf[i] = {
                .oid = {
                    .inode = 1,
                    .stripe = (i << STRIPE_SHIFT) | (osd_num-1),
                },
                .version = (uint64_t)(osd_num == 1 && i >= r.total_count - 10 ? 2 : 1),
            };
        }
        pg.peering_state->list_results[osd_num] = r;
    }
-    return b;
+    pg.calc_object_states();
-}
+    printf("deviation variants=%ld clean=%lu\n", pg.state_dict.size(), pg.clean_count);
-
+    for (auto it: pg.state_dict)
 void jumphash_prepare(int count, uint64_t *out_weights, uint64_t *in_weights)
 {
    if (count <= 0)
    {
-        return;
+        printf("dev: state=%lx\n", it.second.state);
    }
    uint64_t total_weight = in_weights[0];
    out_weights[0] = UINT64_MAX;
    for (int j = 1; j < count; j++)
    {
        total_weight += in_weights[j];
        out_weights[j] = UINT64_MAX / total_weight * in_weights[j];
    }
 }
 uint64_t jumphash_weights(uint64_t key, int count, uint64_t *prepared_weights)
 {
    uint64_t b = 0;
    uint64_t seed = key;
    for (int j = 1; j < count; j++)
    {
        seed = 2862933555777941757ull*seed + 3037000493ull; // LCPRNG
        if (seed < prepared_weights[j])
        {
            b = j;
        }
    }
    return b;
 }
 void jumphash3(uint64_t key, int count, uint64_t *weights, uint64_t *r)
 {
    r[0] = 0;
    r[1] = 1;
    r[2] = 2;
    uint64_t total_weight = weights[0]+weights[1]+weights[2];
    uint64_t seed = key;
    for (int j = 3; j < count; j++)
    {
        seed = 2862933555777941757ull*seed + 3037000493ull; // LCPRNG
        total_weight += weights[j];
        if (seed < UINT64_MAX*1.0*weights[j]/total_weight)
            r[0] = j;
        else
        {
            seed = 2862933555777941757ull*seed + 3037000493ull; // LCPRNG
            if (seed < UINT64_MAX*1.0*weights[j]/total_weight)
                r[1] = j;
            else
            {
                seed = 2862933555777941757ull*seed + 3037000493ull; // LCPRNG
                if (seed < UINT64_MAX*1.0*weights[j]/total_weight)
                    r[2] = j;
            }
        }
    }
 }
 uint64_t crush(uint64_t key, int count, uint64_t *weights)
 {
    uint64_t b = 0;
    uint64_t seed = 0;
    uint64_t max = 0;
    for (int j = 0; j < count; j++)
    {
        seed = (key + 0xc6a4a7935bd1e995 + (seed << 6) + (seed >> 2));
        seed ^= (j + 0xc6a4a7935bd1e995 + (seed << 6) + (seed >> 2));
        seed = 2862933555777941757ull*seed + 3037000493ull; // LCPRNG
        seed = -log(((double)seed) / (1ul << 32) / (1ul << 32)) * weights[j];
        if (seed > max)
        {
            max = seed;
            b = j;
        }
    }
    return b;
 }
 void crush3(uint64_t key, int count, uint64_t *weights, uint64_t *r, uint64_t total_weight)
 {
    uint64_t seed = 0;
    uint64_t max = 0;
    for (int k1 = 0; k1 < count; k1++)
    {
        for (int k2 = k1+1; k2 < count; k2++)
        {
            if (k2 == k1)
            {
                continue;
            }
            for (int k3 = k2+1; k3 < count; k3++)
            {
                if (k3 == k1 || k3 == k2)
                {
                    continue;
                }
                seed = (key + 0xc6a4a7935bd1e995 + (seed << 6) + (seed >> 2));
                seed ^= (k1 + 0xc6a4a7935bd1e995 + (seed << 6) + (seed >> 2));
                seed ^= (k2 + 0xc6a4a7935bd1e995 + (seed << 6) + (seed >> 2));
                seed ^= (k3 + 0xc6a4a7935bd1e995 + (seed << 6) + (seed >> 2));
                seed = 2862933555777941757ull*seed + 3037000493ull; // LCPRNG
                //seed = ((double)seed) / (1ul << 32) / (1ul << 32) * (weights[k1] + weights[k2] + weights[k3]);
                seed = ((double)seed) / (1ul << 32) / (1ul << 32) * (1 -
                    (1 - 1.0*weights[k1]/total_weight)*
                    (1 - 1.0*weights[k2]/total_weight)*
                    (1 - 1.0*weights[k3]/total_weight)
                ) * UINT64_MAX;
                if (seed > max)
                {
                    r[0] = k1;
                    r[1] = k2;
                    r[2] = k3;
                    max = seed;
                }
            }
        }
    }
    return 0;
 }
 int main(int argc, char *argv[])
 {
-    int host_count = 6;
+    timeval fill_start, fill_end, filter_end;
-    uint64_t host_weights[] = {
+    spp::sparse_hash_map<object_id, clean_entry> clean_db;
-        34609*3,
+    //std::map<object_id, clean_entry> clean_db;
-        34931*3,
+    //btree::btree_map<object_id, clean_entry> clean_db;
-        35850+36387+35859,
+    gettimeofday(&fill_start, NULL);
-        36387,
+    printf("filling\n");
-        36387*2,
+    uint64_t total = 1024*1024*8*4;
-        36387,
+    clean_db.resize(total);
-    };
+    for (uint64_t i = 0; i < total; i++)
    /*int osd_count[] = { 3, 3, 3, 1, 2 };
    uint64_t osd_weights[][3] = {
        { 34609, 34609, 34609 },
        { 34931, 34931, 34931 },
        { 35850, 36387, 35859 },
        { 36387 },
        { 36387, 36387 },
    };*/
    uint64_t total_weight = 0;
    for (int i = 0; i < host_count; i++)
    {
-        total_weight += host_weights[i];
+        clean_db[(object_id){
            .inode = 1,
            //.stripe = (i << STRIPE_SHIFT),
            .stripe = (((367*i) % total) << STRIPE_SHIFT),
        }] = (clean_entry){
            .version = 1,
            .location = i << DEFAULT_ORDER,
        };
    }
-    uint64_t host_weights_prepared[host_count];
+    gettimeofday(&fill_end, NULL);
-    jumphash_prepare(host_count, host_weights_prepared, host_weights);
+    // no resize():
-    uint64_t total_pgs[host_count] = { 0 };
+    // spp = 17.87s (seq), 41.81s (rand), 3.29s (seq+resize), 8.3s (rand+resize), ~1.3G RAM in all cases
-    int pg_count = 256;
+    // std::unordered_map = 6.14 sec, ~2.3G RAM
-    double uniformity[pg_count] = { 0 };
+    // std::map = 13 sec (seq), 5.54 sec (rand), ~2.5G RAM
-    for (uint64_t pg = 1; pg <= pg_count; pg++)
+    // cpp-btree = 2.47 sec (seq) ~1.2G RAM, 20.6 sec (pseudo-random 367*i % total) ~1.5G RAM
    printf("filled %.2f sec\n", (fill_end.tv_sec - fill_start.tv_sec) + (fill_end.tv_usec - fill_start.tv_usec) / 1000000.0);
    for (int pg = 0; pg < 100; pg++)
    {
-        uint64_t r[3];
+        obj_ver_id* buf1 = (obj_ver_id*)malloc(sizeof(obj_ver_id) * ((total+99)/100));
-
+        int j = 0;
-/*
+        for (auto it: clean_db)
-        // Select first host
+            if ((it.first % 100) == pg)
-        //r[0] = jumphash_weights(pg, host_count, host_weights_prepared);
+                buf1[j++] = { .oid = it.first, .version = it.second.version };
-        r[0] = crush(pg, host_count, host_weights);
+        free(buf1);
-        // Select second host
+        printf("filtered %d\n", j);
        uint64_t seed = pg;
        r[1] = r[0];
        while (r[1] == r[0])
        {
            seed = 2862933555777941757ull*seed + 3037000493ull; // LCPRNG
            //r[1] = jumphash_weights(seed, host_count, host_weights_prepared);
            r[1] = crush(seed, host_count, host_weights);
        }
        // Select third host
        seed = pg;
        r[2] = r[0];
        while (r[2] == r[0] || r[2] == r[1])
        {
            seed = 2862933555777941757ull*seed + 3037000493ull; // LCPRNG
            //r[2] = jumphash_weights(seed, host_count, host_weights_prepared);
            r[2] = crush(seed, host_count, host_weights);
        }
 */
 /*
        // Select second host
        uint64_t host_weights1[host_count];
        for (int i = 0; i < r[0]; i++)
            host_weights1[i] = host_weights[i];
        for (int i = r[0]+1; i < host_count; i++)
            host_weights1[i-1] = host_weights[i];
        r[1] = crush(pg, host_count-1, host_weights1);
        // Select third host
        for (int i = r[1]+1; i < host_count-1; i++)
            host_weights1[i-1] = host_weights[i];
        r[2] = crush(pg, host_count-2, host_weights1);
        // Transform numbers
        r[2] = r[2] >= r[1] ? 1+r[2] : r[2];
        r[2] = r[2] >= r[0] ? 1+r[2] : r[2];
        r[1] = r[1] >= r[0] ? 1+r[1] : r[1];
 */
        crush3(pg, host_count, host_weights, r, total_weight);
        uint64_t shift = (2862933555777941757ull*pg + 3037000493ull) % host_count;
        if (shift == 1)
        {
            uint64_t tmp;
            tmp = r[0];
            r[0] = r[1];
            r[1] = r[2];
            r[2] = tmp;
        }
        else if (shift == 2)
        {
            uint64_t tmp;
            tmp = r[0];
            r[0] = r[2];
            r[2] = r[1];
            r[1] = tmp;
        }
        total_pgs[r[0]]++;
        total_pgs[r[1]]++;
        total_pgs[r[2]]++;
        double u = 0;
        for (int i = 0; i < host_count; i++)
        {
            double d = abs(1 - total_pgs[i]/3.0/pg * total_weight/host_weights[i]);
            u += d;
        }
        uniformity[pg-1] = u/host_count;
        printf("pg %lu: hosts %lu, %lu, %lu ; avg deviation = %.2f\n", pg, r[0], r[1], r[2], u/host_count);
    }
-    printf("total PGs: ");
+    gettimeofday(&filter_end, NULL);
-    for (int i = 0; i < host_count; i++)
+    // spp = 42.15 sec / 60 sec (rand)
-    {
+    // std::unordered_map = 43.7 sec
-        printf(i > 0 ? ", %lu (%.2f)" : "%lu (%.2f)", total_pgs[i], total_pgs[i]/3.0/pg_count * total_weight/host_weights[i]);
+    // std::map = 156.13 sec
-    }
+    // cpp-btree = 21.87 sec (seq), 44.33 sec (rand)
-    printf("\n");
+    printf("100 times filter %.2f sec\n", (filter_end.tv_sec - fill_end.tv_sec) + (filter_end.tv_usec - fill_end.tv_usec) / 1000000.0);
    return 0;
 }
--- a/test_allocator.cpp
+++ b/test_allocator.cpp
@ -1,6 +1,3 @@
 // Copyright (c) Vitaliy Filippov, 2019+
 // License: VNPL-1.0 (see README.md for details)
 #include <stdio.h>
 #include "allocator.h"
--- a/test_blockstore.cpp
+++ b/test_blockstore.cpp
@ -1,6 +1,3 @@
 // Copyright (c) Vitaliy Filippov, 2019+
 // License: VNPL-1.0 (see README.md for details)
 #include <malloc.h>
 #include "timerfd_interval.h"
 #include "blockstore.h"
@ -118,7 +115,7 @@ int main(int narg, char *args[])
        }
    };
-    ringloop->register_consumer(&main_cons);
+    ringloop->register_consumer(main_cons);
    while (1)
    {
        ringloop->loop();
--- a/test_pattern.h
+++ b/test_pattern.h
@ -1,6 +1,3 @@
 // Copyright (c) Vitaliy Filippov, 2019+
 // License: VNPL-1.0 (see README.md for details)
 #pragma once
 #include <assert.h>
--- a/timerfd_interval.cpp
+++ b/timerfd_interval.cpp
@ -1,6 +1,3 @@
 // Copyright (c) Vitaliy Filippov, 2019+
 // License: VNPL-1.0 or GNU GPL-2.0+ (see README.md for details)
 #include <sys/timerfd.h>
 #include <sys/poll.h>
 #include <unistd.h>
@ -23,14 +20,15 @@ timerfd_interval::timerfd_interval(ring_loop_t *ringloop, int seconds, std::func
        throw std::runtime_error(std::string("timerfd_settime: ") + strerror(errno));
    }
    consumer.loop = [this]() { loop(); };
-    ringloop->register_consumer(&consumer);
+    ringloop->register_consumer(consumer);
    timerfd_index = ringloop->register_fd(timerfd);
    this->ringloop = ringloop;
    this->callback = cb;
 }
 timerfd_interval::~timerfd_interval()
 {
-    ringloop->unregister_consumer(&consumer);
+    ringloop->unregister_consumer(consumer);
    close(timerfd);
 }
@ -47,10 +45,12 @@ void timerfd_interval::loop()
        return;
    }
    struct ring_data_t *data = ((ring_data_t*)sqe->user_data);
-    my_uring_prep_poll_add(sqe, timerfd, POLLIN);
+    my_uring_prep_poll_add(sqe, timerfd_index, POLLIN);
    sqe->flags |= IOSQE_FIXED_FILE;
    data->allow_cancel = true;
    data->callback = [&](ring_data_t *data)
    {
-        if (data->res < 0)
+        if (data->res < 0 && data->res != -ECANCELED)
        {
            throw std::runtime_error(std::string("waiting for timer failed: ") + strerror(-data->res));
        }
--- a/Show More
+++ b/Show More
		`@ -1 +0,0 @@`
			`Subproject commit 5dc108754ad40d3b1d024f9bd7cca0595ef1a1db`
		`@ -1 +0,0 @@`
			`Subproject commit 97f06cb20c1e136fd37d58fb40f57dd8f8a3a4a7`