Btrfs: fix endless loop in balancing block groups

Qgroup function may overwrite the saved error 'err' with 0
in case quota is not enabled, and this ends up with a
endless loop in balance because we keep going back to balance
the same block group.

It really should use 'ret' instead.

Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Reviewed-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.com>

1 files changed, 5 insertions, 3 deletions

diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
index 8a2c2a07987b..c0c13dc6fe12 100644
--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -4200,9 +4200,11 @@ restart:
                 err = PTR_ERR(trans);
                 goto out_free;
         }
-        err = qgroup_fix_relocated_data_extents(trans, rc);
-        if (err < 0) {
-                btrfs_abort_transaction(trans, err);
+        ret = qgroup_fix_relocated_data_extents(trans, rc);
+        if (ret < 0) {
+                btrfs_abort_transaction(trans, ret);
+                if (!err)
+                        err = ret;
                 goto out_free;
         }
         btrfs_commit_transaction(trans, rc->extent_root);