[PATCH 5.10 / 5.4 / 4.19] btrfs: add missing mutex_unlock in btrfs_relocate_sys_chunks()

[Dominique Martinet <dominique.martinet@atmark-techno.com>]

[ Upstream commit 9af503d91298c3f2945e73703f0e00995be08c30 ]

The previous patch that replaced BUG_ON by error handling forgot to
unlock the mutex in the error path.

Link: https://lore.kernel.org/all/Zh%2fHpAGFqa7YAFuM@duo.ucw.cz
Reported-by: Pavel Machek <pavel@denx.de>
Fixes: 7411055db5ce ("btrfs: handle chunk tree lookup error in btrfs_relocate_sys_chunks()")
Cc: stable@vger.kernel.org
Reviewed-by: Pavel Machek <pavel@denx.de>
Signed-off-by: Dominique Martinet <dominique.martinet@atmark-techno.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Dominique Martinet <dominique.martinet@atmark-techno.com>
---
The conflict is in 7411055db5ce ("btrfs: handle chunk tree lookup error
in btrfs_relocate_sys_chunks()") but that no longer cleanly applies
after the backport of 7411055db5ce ("btrfs: handle chunk tree lookup
error in btrfs_relocate_sys_chunks()"); it's probably simpler to just
use the old mutex name directly.

This commit applies and builds on 4.19.313, 5.4.275 and 5.10.216

 fs/btrfs/volumes.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 09c23626feba..2d3aeef01c9e 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -3187,6 +3187,7 @@ static int btrfs_relocate_sys_chunks(struct btrfs_fs_info *fs_info)
 			 * alignment and size).
 			 */
 			ret = -EUCLEAN;
+			mutex_unlock(&fs_info->delete_unused_bgs_mutex);
 			goto error;
 		}
 
-- 
2.39.2