From: Liu Bo <bo.li.liu@xxxxxxxxxx> [ Upstream commit e321f8a801d7b4c40da8005257b05b9c2b51b072 ] If @block_group is not @used_bg, it'll try to get @used_bg's lock without droping @block_group 's lock and lockdep has throwed a scary deadlock warning about it. Fix it by using down_read_nested. Signed-off-by: Liu Bo <bo.li.liu@xxxxxxxxxx> Reviewed-by: David Sterba <dsterba@xxxxxxxx> Signed-off-by: David Sterba <dsterba@xxxxxxxx> Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxx> --- fs/btrfs/extent-tree.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c index e46e7fbe1b34..14a37ff0b9e3 100644 --- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -7401,7 +7401,8 @@ btrfs_lock_cluster(struct btrfs_block_group_cache *block_group, spin_unlock(&cluster->refill_lock); - down_read(&used_bg->data_rwsem); + /* We should only have one-level nested. */ + down_read_nested(&used_bg->data_rwsem, SINGLE_DEPTH_NESTING); spin_lock(&cluster->refill_lock); if (used_bg == cluster->block_group) -- 2.11.0