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>

diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
index 8a2c2a07987b2e02b6023428b4b931940baffc03..c0c13dc6fe1286673982dfa78d9930cb219927dd 100644 (file)
--- 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);