Btrfs: move btrfs_free_qgroup_config() out of spin_lock and fix comments

btrfs_free_qgroup_config() is not only called by open/close_ctree(),but
also btrfs_disable_quota().And for btrfs_disable_quota(),we have set
'quota_root' to be null before calling btrfs_free_qgroup_config(),so it
is safe to cleanup in-memory structures without lock held.

Signed-off-by: Wang Shilong <wangsl.fnst@cn.fujitsu.com>
Reviewed-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>

1 files changed, 6 insertions, 3 deletions

diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c
index 57b9805873f7..01eeffe9ae53 100644
--- a/fs/btrfs/qgroup.c
+++ b/fs/btrfs/qgroup.c
@@ -432,8 +432,10 @@ out:
 }
 
 /*
- * This is only called from close_ctree() or open_ctree(), both in single-
- * treaded paths. Clean up the in-memory structures. No locking needed.
+ * This is called from close_ctree() or open_ctree() or btrfs_quota_disable(),
+ * first two are in single-threaded paths.And for the third one, we have set
+ * quota_root to be null with qgroup_lock held before, so it is safe to clean
+ * up the in-memory structures without qgroup_lock held.
  */
 void btrfs_free_qgroup_config(struct btrfs_fs_info *fs_info)
 {
@@ -937,9 +939,10 @@ int btrfs_quota_disable(struct btrfs_trans_handle *trans,
         fs_info->pending_quota_state = 0;
         quota_root = fs_info->quota_root;
         fs_info->quota_root = NULL;
-        btrfs_free_qgroup_config(fs_info);
         spin_unlock(&fs_info->qgroup_lock);
 
+        btrfs_free_qgroup_config(fs_info);
+
         if (!quota_root) {
                 ret = -EINVAL;
                 goto out;