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dm: fix zoned locking imbalance due to needless check in clone_endio 

After the commit ca522482e3 ("dm: pass NULL bdev to bio_alloc_clone"),
clone_endio() only calls dm_zone_endio() when DM targets remap the
clone bio's bdev to something other than the md->disk->part0 default.

However, if a DM target (e.g. dm-crypt) stacked ontop of a dm-zoned
does not remap the clone bio using bio_set_dev() then dm_zone_endio()
is not called at completion of the bios and zone locks are not
properly unlocked. This triggers a hang, in dm_zone_map_bio(), when
blktests block/004 is run for dm-crypt on zoned block devices. To
avoid the hang, simply remove the clone_endio() check that verifies
the target remapped the clone bio to a device other than the default.

Fixes: ca522482e3 ("dm: pass NULL bdev to bio_alloc_clone")
Reported-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
This commit is contained in:
Mike Snitzer 2022-06-10 15:07:48 -04:00
parent d5a37b1998
commit dddf305640
1 changed files with 11 additions and 15 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

26
drivers/md/dm.c
View File

@ -1016,23 +1016,19 @@ static void clone_endio(struct bio *bio)
struct dm_io *io = tio->io;
struct mapped_device *md = io->md;
if (likely(bio->bi_bdev != md->disk->part0)) {
struct request_queue *q = bdev_get_queue(bio->bi_bdev);
if (unlikely(error == BLK_STS_TARGET)) {
if (bio_op(bio) == REQ_OP_DISCARD &&
!bdev_max_discard_sectors(bio->bi_bdev))
disable_discard(md);
else if (bio_op(bio) == REQ_OP_WRITE_ZEROES &&
!q->limits.max_write_zeroes_sectors)
disable_write_zeroes(md);
}
if (static_branch_unlikely(&zoned_enabled) &&
unlikely(blk_queue_is_zoned(q)))
dm_zone_endio(io, bio);
if (unlikely(error == BLK_STS_TARGET)) {
if (bio_op(bio) == REQ_OP_DISCARD &&
!bdev_max_discard_sectors(bio->bi_bdev))
disable_discard(md);
else if (bio_op(bio) == REQ_OP_WRITE_ZEROES &&
!bdev_write_zeroes_sectors(bio->bi_bdev))
disable_write_zeroes(md);
}
if (static_branch_unlikely(&zoned_enabled) &&
unlikely(blk_queue_is_zoned(bdev_get_queue(bio->bi_bdev))))
dm_zone_endio(io, bio);
if (endio) {
int r = endio(ti, bio, &error);
switch (r) {