The commit 92986f6b4c8a ("dm: use bio_clone_fast in alloc_io/alloc_tio")
removed bio_clone_fast() call from alloc_tio() when ci->io->tio is
available. In this case, ci->bio is not copied to ci->io->tio.clone.
This is fine since init_clone_info() sets same values to ci->bio and
ci->io->tio.clone.
However, when incoming bios have REQ_PREFLUSH flag, __send_empty_flush()
prepares a zero length bio on stack and set it to ci->bio. At this time,
ci->io->tio.clone still keeps non-zero length. When alloc_tio() chooses
this ci->io->tio.clone as the bio to map, it is passed to targets as
non-empty flush bio. It causes bio length check failure in dm-zoned and
unexpected operation such as dm_accept_partial_bio() call.
To avoid the non-empty flush bio, set zero length to ci->io->tio.clone
in __send_empty_flush().
Fixes: 92986f6b4c8a ("dm: use bio_clone_fast in alloc_io/alloc_tio")
Signed-off-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@xxxxxxx>
---
drivers/md/dm.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 3c5fad7c4ee6..f2397546b93f 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1392,6 +1392,7 @@ static void __send_empty_flush(struct clone_info *ci)
ci->bio = &flush_bio;
ci->sector_count = 0;
+ ci->io->tio.clone.bi_iter.bi_size = 0;
while ((ti = dm_table_get_target(ci->map, target_nr++)))
__send_duplicate_bios(ci, ti, ti->num_flush_bios, NULL);
--
2.35.1
--
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