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| author | Mikulas Patocka <mpatocka@redhat.com> | 2026-09-30 21:35:31 +0200 |
|---|---|---|
| committer | Mikulas Patocka <mpatocka@redhat.com> | 2026-10-01 13:01:57 +0200 |
| commit | a279804752e6c767b7f9ecbb32a15bdfd2b80aea (patch) | |
| tree | 7df436796f98b9a14d2b7045bd6f17c472f3a92c /tools/lib/python/kdoc | |
| parent | 99909b74fb34174b22965c397782cd1a370517ff (diff) | |
dm: fix a bug in dm_accept_partial_bio
dm-writecache doesn't work in pmem mode - mkfs.ext4 and the following
fsck.ext4 fail with data corruption reported.
The commit 7dd76d1feec7 ("dm: improve bio splitting and associated IO
accounting") introduced a latent bug in dm_accept_partial_bio - it set
tio->io->sectors = n_sectors;. This is incorrect, according to the
diagram in the source code at dm_accept_partial_bio, it should be the
size of regions 1+2, not the region 2 alone.
The latent bug become real bug with the commit 8b211aaccb91 ("dm: add two
stage requeue mechanism").
dm-writecache in pmem mode is the only target that actually advances bio
with bio_advance and then calls dm_accept_partial_bio (so, the region 1
is non-empty). All the other targets call dm_accept_partial_bio with
region 1 empty, so bug went unnoticed for so long.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Assisted-by: Claude:claude-opus-5
Cc: stable@vger.kernel.org
Fixes: 8b211aaccb91 ("dm: add two stage requeue mechanism")
Diffstat (limited to 'tools/lib/python/kdoc')
0 files changed, 0 insertions, 0 deletions