From f16dba5dc6f094041ab8c356e1e3a48ee0e3c8cd Mon Sep 17 00:00:00 2001 From: Mikulas Patocka Date: Tue, 25 May 2021 13:16:21 -0400 Subject: [PATCH] dm snapshot: revert "fix a crash when an origin has no snapshots" Commit 7ee06ddc4038f936b0d4459d37a7d4d844fb03db ("dm snapshot: fix a crash when an origin has no snapshots") introduced a regression in snapshot merging - causing the lvm2 test lvcreate-cache-snapshot.sh got stuck in an infinite loop. Even though commit 7ee06ddc4038f936b0d4459d37a7d4d844fb03db was marked for stable@ the stable team was notified to _not_ backport it. Fixes: 7ee06ddc4038 ("dm snapshot: fix a crash when an origin has no snapshots") Signed-off-by: Mikulas Patocka Signed-off-by: Mike Snitzer --- drivers/md/dm-snap.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/md/dm-snap.c b/drivers/md/dm-snap.c index b8e4d31..75e59294 100644 --- a/drivers/md/dm-snap.c +++ b/drivers/md/dm-snap.c @@ -855,11 +855,12 @@ static int dm_add_exception(void *context, chunk_t old, chunk_t new) static uint32_t __minimum_chunk_size(struct origin *o) { struct dm_snapshot *snap; - unsigned chunk_size = rounddown_pow_of_two(UINT_MAX); + unsigned chunk_size = 0; if (o) list_for_each_entry(snap, &o->snapshots, list) - chunk_size = min(chunk_size, snap->store->chunk_size); + chunk_size = min_not_zero(chunk_size, + snap->store->chunk_size); return (uint32_t) chunk_size; } -- 2.7.4