| Message ID | 1481673520-30560-1-git-send-email-bo.li.liu@oracle.com (mailing list archive) |
|---|---|
| State | Accepted |
| Headers | show |
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c index 4607af3..68e9d25 100644 --- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -7397,7 +7397,8 @@ 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)
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@oracle.com> --- v2: Use 'SINGLE_DEPTH_NESTING' to avoid magic number. fs/btrfs/extent-tree.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)