diff --git a/block.c b/block.c
index 179d27ac75..932ce58265 100644
--- a/block.c
+++ b/block.c
@@ -3141,10 +3141,13 @@ static int coroutine_fn bdrv_aligned_pwritev(BlockDriverState *bs,
if (ret < 0) {
/* Do nothing, write notifier decided to fail this request */
} else if (flags & BDRV_REQ_ZERO_WRITE) {
+ BLKDBG_EVENT(bs, BLKDBG_PWRITEV_ZERO);
ret = bdrv_co_do_write_zeroes(bs, sector_num, nb_sectors, flags);
} else {
+ BLKDBG_EVENT(bs, BLKDBG_PWRITEV);
ret = drv->bdrv_co_writev(bs, sector_num, nb_sectors, qiov);
}
+ BLKDBG_EVENT(bs, BLKDBG_PWRITEV_DONE);
if (ret == 0 && !bs->enable_write_cache) {
ret = bdrv_co_flush(bs);
@@ -3215,11 +3218,13 @@ static int coroutine_fn bdrv_co_do_pwritev(BlockDriverState *bs,
};
qemu_iovec_init_external(&head_qiov, &head_iov, 1);
+ BLKDBG_EVENT(bs, BLKDBG_PWRITEV_RMW_HEAD);
ret = bdrv_aligned_preadv(bs, &req, offset & ~(align - 1), align,
align, &head_qiov, 0);
if (ret < 0) {
goto fail;
}
+ BLKDBG_EVENT(bs, BLKDBG_PWRITEV_RMW_AFTER_HEAD);
qemu_iovec_init(&local_qiov, qiov->niov + 2);
qemu_iovec_add(&local_qiov, head_buf, offset & (align - 1));
@@ -3247,11 +3252,13 @@ static int coroutine_fn bdrv_co_do_pwritev(BlockDriverState *bs,
};
qemu_iovec_init_external(&tail_qiov, &tail_iov, 1);
+ BLKDBG_EVENT(bs, BLKDBG_PWRITEV_RMW_TAIL);
ret = bdrv_aligned_preadv(bs, &req, (offset + bytes) & ~(align - 1), align,
align, &tail_qiov, 0);
if (ret < 0) {
goto fail;
}
+ BLKDBG_EVENT(bs, BLKDBG_PWRITEV_RMW_AFTER_TAIL);
if (!use_local_qiov) {
qemu_iovec_init(&local_qiov, qiov->niov + 1);
diff --git a/block/blkdebug.c b/block/blkdebug.c
index 2c03698f93..56c4cd084f 100644
--- a/block/blkdebug.c
+++ b/block/blkdebug.c
@@ -186,6 +186,14 @@ static const char *event_names[BLKDBG_EVENT_MAX] = {
[BLKDBG_FLUSH_TO_OS] = "flush_to_os",
[BLKDBG_FLUSH_TO_DISK] = "flush_to_disk",
+
+ [BLKDBG_PWRITEV_RMW_HEAD] = "pwritev_rmw.head",
+ [BLKDBG_PWRITEV_RMW_AFTER_HEAD] = "pwritev_rmw.after_head",
+ [BLKDBG_PWRITEV_RMW_TAIL] = "pwritev_rmw.tail",
+ [BLKDBG_PWRITEV_RMW_AFTER_TAIL] = "pwritev_rmw.after_tail",
+ [BLKDBG_PWRITEV] = "pwritev",
+ [BLKDBG_PWRITEV_ZERO] = "pwritev_zero",
+ [BLKDBG_PWRITEV_DONE] = "pwritev_done",
};
static int get_event_by_name(const char *name, BlkDebugEvent *event)
diff --git a/include/block/block.h b/include/block/block.h
index 1085992a7a..963a61fa4c 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -527,6 +527,14 @@ typedef enum {
BLKDBG_FLUSH_TO_OS,
BLKDBG_FLUSH_TO_DISK,
+ BLKDBG_PWRITEV_RMW_HEAD,
+ BLKDBG_PWRITEV_RMW_AFTER_HEAD,
+ BLKDBG_PWRITEV_RMW_TAIL,
+ BLKDBG_PWRITEV_RMW_AFTER_TAIL,
+ BLKDBG_PWRITEV,
+ BLKDBG_PWRITEV_ZERO,
+ BLKDBG_PWRITEV_DONE,
+
BLKDBG_EVENT_MAX,
} BlkDebugEvent;
diff --git a/tests/qemu-iotests/077 b/tests/qemu-iotests/077
new file mode 100755
index 0000000000..bbf7b5145a
--- /dev/null
+++ b/tests/qemu-iotests/077
@@ -0,0 +1,278 @@
+#!/bin/bash
+#
+# Test concurrent pread/pwrite
+#
+# Copyright (C) 2014 Red Hat, Inc.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 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
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see .
+#
+
+# creator
+owner=kwolf@redhat.com
+
+seq=`basename $0`
+echo "QA output created by $seq"
+
+here=`pwd`
+tmp=/tmp/$$
+status=1 # failure is the default!
+
+_cleanup()
+{
+ _cleanup_test_img
+}
+trap "_cleanup; exit \$status" 0 1 2 3 15
+
+# get standard environment, filters and checks
+. ./common.rc
+. ./common.filter
+
+_supported_fmt generic
+_supported_proto generic
+_supported_os Linux
+
+CLUSTER_SIZE=4k
+size=128M
+
+_make_test_img $size
+
+echo
+echo "== Some concurrent requests involving RMW =="
+
+function test_io()
+{
+echo "open -o file.align=4k blkdebug::$TEST_IMG"
+# A simple RMW request
+cat <