[PATCH v2 3/6] btrfs: qgroup: fix leak of qgroups in rb tree after failure to enable quotas

[fdmanana@kernel.org]

From: Filipe Manana <fdmanana@suse.com>

When enabling quotas we add struct btrfs_qroup items to the rbtree
fs_info->qgroup_tree, however if there's an error during the quota enable
operation after adding those items, we exit without removing the items
from the rbtree and freeing them.

Fix this by calling btrfs_free_qgroup_config() on error, which also
deletes all sysfs entries (it calls btrfs_sysfs_del_qgroups()).

Signed-off-by: Filipe Manana <fdmanana@suse.com>
---
 fs/btrfs/qgroup.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c
index 4b6c82a24bc5..9f21b091c545 100644
--- a/fs/btrfs/qgroup.c
+++ b/fs/btrfs/qgroup.c
@@ -1293,8 +1293,13 @@ int btrfs_quota_enable(struct btrfs_fs_info *fs_info,
 	if (ret)
 		btrfs_put_root(quota_root);
 out:
-	if (ret)
-		btrfs_sysfs_del_qgroups(fs_info);
+	if (ret) {
+		/*
+		 * Free all qgroups previously added with add_qgroup_rb() and
+		 * sysfs entries.
+		 */
+		btrfs_free_qgroup_config(fs_info);
+	}
 	mutex_unlock(&fs_info->qgroup_ioctl_lock);
 	if (ret && trans)
 		btrfs_end_transaction(trans);
-- 
2.47.2