mirror_qemu/block
Ari Sundholm 23a512f418 block/blklogwrites: Fix a bug when logging "write zeroes" operations.
There is a bug in the blklogwrites driver pertaining to logging "write
zeroes" operations, causing log corruption. This can be easily observed
by setting detect-zeroes to something other than "off" for the driver.

The issue is caused by a concurrency bug pertaining to the fact that
"write zeroes" operations have to be logged in two parts: first the log
entry metadata, then the zeroed-out region. While the log entry
metadata is being written by bdrv_co_pwritev(), another operation may
begin in the meanwhile and modify the state of the blklogwrites driver.
This is as intended by the coroutine-driven I/O model in QEMU, of
course.

Unfortunately, this specific scenario is mishandled. A short example:
    1. Initially, in the current operation (#1), the current log sector
number in the driver state is only incremented by the number of sectors
taken by the log entry metadata, after which the log entry metadata is
written. The current operation yields.
    2. Another operation (#2) may start while the log entry metadata is
being written. It uses the current log position as the start offset for
its log entry. This is in the sector right after the operation #1 log
entry metadata, which is bad!
    3. After bdrv_co_pwritev() returns (#1), the current log sector
number is reread from the driver state in order to find out the start
offset for bdrv_co_pwrite_zeroes(). This is an obvious blunder, as the
offset will be the sector right after the (misplaced) operation #2 log
entry, which means that the zeroed-out region begins at the wrong
offset.
    4. As a result of the above, the log is corrupt.

Fix this by only reading the driver metadata once, computing the
offsets and sizes in one go (including the optional zeroed-out region)
and setting the log sector number to the appropriate value for the next
operation in line.

Signed-off-by: Ari Sundholm <ari@tuxera.com>
Cc: qemu-stable@nongnu.org
Message-ID: <20240109184646.1128475-1-megari@gmx.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
(cherry picked from commit a9c8ea9547)
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
2024-01-26 18:35:56 +03:00
..
export vhost-user: fully use new backend/frontend naming 2023-06-26 09:50:00 -04:00
monitor meson: Replace softmmu_ss -> system_ss 2023-06-20 10:01:30 +02:00
accounting.c block: add missed block_acct_setup with new block device init procedure 2022-09-30 18:42:34 +02:00
aio_task.c block/aio_task: assert `max_busy_tasks` is greater than 0 2021-10-05 18:56:41 +02:00
amend.c block: Mark BlockDriver callbacks for amend job GRAPH_RDLOCK 2023-05-10 14:16:54 +02:00
backup.c Block layer patches 2023-02-24 15:09:39 +00:00
blkdebug.c blkdebug: add missing coroutine_fn annotation 2023-04-25 13:17:28 +02:00
blkio.c block/blkio: add more comments on the fd passing handling 2023-08-03 11:28:43 -04:00
blklogwrites.c block/blklogwrites: Fix a bug when logging "write zeroes" operations. 2024-01-26 18:35:56 +03:00
blkreplay.c block: Mark bdrv_co_refresh_total_sectors() and callers GRAPH_RDLOCK 2023-02-23 19:49:33 +01:00
blkverify.c block: Mark bdrv_recurse_can_replace() and callers GRAPH_RDLOCK 2023-05-10 14:16:54 +02:00
block-backend.c block: add blk_io_plug_call() API 2023-06-01 07:34:03 -04:00
block-copy.c block: Mark bdrv_co_pwrite_zeroes() and callers GRAPH_RDLOCK 2023-02-23 19:49:14 +01:00
block-gen.h block-coroutine-wrapper.py: support also basic return types 2022-12-15 16:07:43 +01:00
block-ram-registrar.c block: add BlockRAMRegistrar 2022-10-26 14:56:42 -04:00
bochs.c bochs: mark more functions as coroutine_fns and GRAPH_RDLOCK 2023-06-28 09:46:24 +02:00
cloop.c cloop: mark more functions as coroutine_fns and GRAPH_RDLOCK 2023-06-28 09:46:27 +02:00
commit.c blockjob: Adhere to rate limit even when reentered early 2023-05-19 19:12:12 +02:00
copy-before-write.c copy-before-write: Fix open with child in iothread 2023-05-30 17:29:35 +02:00
copy-before-write.h block/copy-before-write.h: global state API + assertions 2022-03-04 18:18:25 +01:00
copy-on-read.c block: remove has_variable_length from filters 2023-04-11 16:38:56 +02:00
copy-on-read.h Clean up ill-advised or unusual header guards 2022-05-11 16:50:01 +02:00
coroutines.h nbd: Mark nbd_co_do_establish_connection() and callers GRAPH_RDLOCK 2023-05-10 14:16:53 +02:00
create.c block: Call .bdrv_co_create(_opts) unlocked 2023-05-19 19:12:12 +02:00
crypto.c block: Call .bdrv_co_create(_opts) unlocked 2023-05-19 19:12:12 +02:00
crypto.h nomaintainer: Fix Lesser GPL version number 2020-11-15 17:04:40 +01:00
curl.c aio: remove aio_disable_external() API 2023-05-30 17:37:26 +02:00
dirty-bitmap.c block: Mark bdrv_*_dirty_bitmap() and callers GRAPH_RDLOCK 2023-02-23 19:49:32 +01:00
dmg-bz2.c Include qemu-common.h exactly where needed 2019-06-12 13:20:20 +02:00
dmg-lzfse.c block/dmg: Ignore C99 prototype declaration mismatch from <lzfse.h> 2023-03-30 15:03:36 +02:00
dmg.c dmg: mark more functions as coroutine_fns and GRAPH_RDLOCK 2023-06-28 09:46:28 +02:00
dmg.h block/dmg: Declare a type definition for DMG uncompress function 2023-04-24 13:53:44 -04:00
file-posix.c file-posix: fix over-writing of returning zone_append offset 2023-11-09 16:39:13 +03:00
file-win32.c thread-pool: avoid passing the pool parameter every time 2023-04-25 13:17:28 +02:00
filter-compress.c block: remove has_variable_length from filters 2023-04-11 16:38:56 +02:00
gluster.c cutils: Adjust signature of parse_uint[_full] 2023-06-02 12:27:19 -05:00
graph-lock.c Revert "graph-lock: Disable locking for now" 2023-06-28 08:46:26 +02:00
io.c block/io: clear BDRV_BLOCK_RECURSE flag after recursing in bdrv_co_block_status 2024-01-25 19:14:05 +03:00
io_uring.c block/io_uring: convert to blk_io_plug_call() API 2023-06-01 07:34:03 -04:00
iscsi-opts.c modules: add block module annotations 2021-07-09 18:20:27 +02:00
iscsi.c aio: remove aio_disable_external() API 2023-05-30 17:37:26 +02:00
linux-aio.c block/linux-aio: convert to blk_io_plug_call() API 2023-06-01 07:34:03 -04:00
meson.build meson: Replace softmmu_ss -> system_ss 2023-06-20 10:01:30 +02:00
mirror.c mirror: Hold main AioContext lock for calling bdrv_open_backing_file() 2023-05-30 17:21:23 +02:00
nbd.c nbd/client: Simplify cookie vs. index computation 2023-07-19 15:26:13 -05:00
nfs.c cutils: Adjust signature of parse_uint[_full] 2023-06-02 12:27:19 -05:00
null.c block: Convert bdrv_get_allocated_file_size() to co_wrapper 2023-02-01 16:52:32 +01:00
nvme.c block/nvme: nvme_process_completion() fix bound for cid 2023-11-09 16:39:13 +03:00
parallels-ext.c util/uuid: Add UUID_STR_LEN definition 2023-11-09 16:39:13 +03:00
parallels.c block: use bdrv_co_getlength in coroutine context 2023-06-28 09:46:33 +02:00
parallels.h parallels: support bitmap extension for read-only mode 2021-03-08 14:56:55 +01:00
plug.c block: add blk_io_plug_call() API 2023-06-01 07:34:03 -04:00
preallocate.c block: remove has_variable_length from filters 2023-04-11 16:38:56 +02:00
progress_meter.c coroutine: Clean up superfluous inclusion of qemu/lockable.h 2023-01-19 10:18:28 +01:00
qapi-sysemu.c block: Fix locking in media change monitor commands 2023-11-01 12:51:23 +03:00
qapi.c block: add accounting for zone append operation 2023-05-15 08:18:10 -04:00
qcow.c block: use bdrv_co_debug_event in coroutine context 2023-06-28 09:46:34 +02:00
qcow2-bitmap.c qcow2: mark more functions as coroutine_fns and GRAPH_RDLOCK 2023-06-28 09:46:32 +02:00
qcow2-cache.c include/block: Untangle inclusion loops 2023-01-20 07:24:28 +01:00
qcow2-cluster.c qcow2: keep reference on zeroize with discard-no-unref enabled 2023-11-09 16:39:13 +03:00
qcow2-refcount.c block: use bdrv_co_debug_event in coroutine context 2023-06-28 09:46:34 +02:00
qcow2-snapshot.c qcow2: mark various functions as coroutine_fn and GRAPH_RDLOCK 2023-04-25 13:17:28 +02:00
qcow2-threads.c thread-pool: avoid passing the pool parameter every time 2023-04-25 13:17:28 +02:00
qcow2.c block: use bdrv_co_debug_event in coroutine context 2023-06-28 09:46:34 +02:00
qcow2.h qcow2: mark more functions as coroutine_fns and GRAPH_RDLOCK 2023-06-28 09:46:32 +02:00
qed-check.c qed: mark more functions as coroutine_fns and GRAPH_RDLOCK 2023-06-28 09:46:20 +02:00
qed-cluster.c qed: protect table cache with CoMutex 2017-07-17 11:34:11 +08:00
qed-l2-cache.c osdep: Move memalign-related functions to their own header 2022-03-07 13:16:49 +00:00
qed-table.c block: use bdrv_co_debug_event in coroutine context 2023-06-28 09:46:34 +02:00
qed.c block: use bdrv_co_debug_event in coroutine context 2023-06-28 09:46:34 +02:00
qed.h block: Mark public read/write functions GRAPH_RDLOCK 2023-02-23 19:49:17 +01:00
quorum.c block: Mark bdrv_recurse_can_replace() and callers GRAPH_RDLOCK 2023-05-10 14:16:54 +02:00
raw-format.c block: use bdrv_co_debug_event in coroutine context 2023-06-28 09:46:34 +02:00
rbd.c block/rbd: Add support for layered encryption 2023-02-23 19:49:35 +01:00
replication.c block: remove has_variable_length from filters 2023-04-11 16:38:56 +02:00
reqlist.c block/reqlist: add reqlist_wait_all() 2022-03-07 09:33:30 +01:00
snapshot-access.c block: Mark preadv_snapshot/snapshot_block_status GRAPH_RDLOCK 2023-02-23 19:49:21 +01:00
snapshot.c block: Fix crash when loading snapshot on inactive node 2023-12-22 22:25:28 +03:00
ssh.c aio: remove aio_disable_external() API 2023-05-30 17:37:26 +02:00
stream.c blockjob: Adhere to rate limit even when reentered early 2023-05-19 19:12:12 +02:00
throttle-groups.c block/throttle-groups: throttle_group_co_io_limits_intercept(): 64bit bytes 2021-02-03 08:14:00 -06:00
throttle.c block: Mark bdrv_co_refresh_total_sectors() and callers GRAPH_RDLOCK 2023-02-23 19:49:33 +01:00
trace-events block/io_uring: convert to blk_io_plug_call() API 2023-06-01 07:34:03 -04:00
trace.h trace: switch position of headers to what Meson requires 2020-08-21 06:18:24 -04:00
vdi.c util/uuid: Add UUID_STR_LEN definition 2023-11-09 16:39:13 +03:00
vhdx-endian.c Include qemu-common.h exactly where needed 2019-06-12 13:20:20 +02:00
vhdx-log.c vhdx: mark more functions as coroutine_fns and GRAPH_RDLOCK 2023-06-28 09:46:30 +02:00
vhdx.c vhdx: mark more functions as coroutine_fns and GRAPH_RDLOCK 2023-06-28 09:46:30 +02:00
vhdx.h vhdx: mark more functions as coroutine_fns and GRAPH_RDLOCK 2023-06-28 09:46:30 +02:00
vmdk.c vmdk: Don't corrupt desc file in vmdk_write_cid 2023-12-05 12:32:35 +03:00
vpc.c vpc: mark more functions as coroutine_fns and GRAPH_RDLOCK 2023-06-28 09:46:23 +02:00
vvfat.c vvfat: mark various functions as coroutine_fn 2023-04-25 13:17:28 +02:00
win32-aio.c aio: remove aio_disable_external() API 2023-05-30 17:37:26 +02:00
write-threshold.c include/block: Untangle inclusion loops 2023-01-20 07:24:28 +01:00