[PATCH] btrfs: free qgroup configuration when quota enable fails

[Guanjie Chen]

Quota enable adds qgroups to fs_info->qgroup_tree before the operation is
guaranteed to succeed.  On failure, the current error path removes only the
sysfs entries, leaving the qgroups and their relations in memory.

Use btrfs_free_qgroup_config() instead.  It is the existing qgroup teardown
helper and removes the in-memory qgroups, their relations and the sysfs
entries.

This is safe because the failure cleanup runs with qgroup_ioctl_lock held
and before quota_root is published or quota accounting is enabled.  Qgroups
already added to the tree are freed by btrfs_free_qgroup_config(), while an
untransferred preallocation and quota_root are still released by the
existing cleanup code.  Transaction handling is unchanged.

Signed-off-by: Guanjie Chen <jk.chen1095@xxxxxxxxx>
---
 fs/btrfs/qgroup.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c
--- a/fs/btrfs/qgroup.c
+++ b/fs/btrfs/qgroup.c
@@ -1292,7 +1292,7 @@ out_free_root:
 		btrfs_put_root(quota_root);
 out:
 	if (ret)
-		btrfs_sysfs_del_qgroups(fs_info);
+		btrfs_free_qgroup_config(fs_info);
 	mutex_unlock(&fs_info->qgroup_ioctl_lock);
 	if (ret && trans)
 		btrfs_end_transaction(trans);
-- 
2.43.0