1 files changed, 41 insertions, 5 deletions

diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c
index f9fb52e52bb6..f175471da882 100644
--- a/fs/btrfs/qgroup.c
+++ b/fs/btrfs/qgroup.c
@@ -956,6 +956,7 @@ int btrfs_add_qgroup_relation(struct btrfs_trans_handle *trans,
         struct btrfs_root *quota_root;
         struct btrfs_qgroup *parent;
         struct btrfs_qgroup *member;
+        struct btrfs_qgroup_list *list;
         int ret = 0;
 
         mutex_lock(&fs_info->qgroup_ioctl_lock);
@@ -971,6 +972,14 @@ int btrfs_add_qgroup_relation(struct btrfs_trans_handle *trans,
                 goto out;
         }
 
+        /* check if such qgroup relation exist firstly */
+        list_for_each_entry(list, &member->groups, next_group) {
+                if (list->group == parent) {
+                        ret = -EEXIST;
+                        goto out;
+                }
+        }
+
         ret = add_qgroup_relation_item(trans, quota_root, src, dst);
         if (ret)
                 goto out;
@@ -993,6 +1002,9 @@ int btrfs_del_qgroup_relation(struct btrfs_trans_handle *trans,
                               struct btrfs_fs_info *fs_info, u64 src, u64 dst)
 {
         struct btrfs_root *quota_root;
+        struct btrfs_qgroup *parent;
+        struct btrfs_qgroup *member;
+        struct btrfs_qgroup_list *list;
         int ret = 0;
         int err;
 
@@ -1003,6 +1015,21 @@ int btrfs_del_qgroup_relation(struct btrfs_trans_handle *trans,
                 goto out;
         }
 
+        member = find_qgroup_rb(fs_info, src);
+        parent = find_qgroup_rb(fs_info, dst);
+        if (!member || !parent) {
+                ret = -EINVAL;
+                goto out;
+        }
+
+        /* check if such qgroup relation exist firstly */
+        list_for_each_entry(list, &member->groups, next_group) {
+                if (list->group == parent)
+                        goto exist;
+        }
+        ret = -ENOENT;
+        goto out;
+exist:
         ret = del_qgroup_relation_item(trans, quota_root, src, dst);
         err = del_qgroup_relation_item(trans, quota_root, dst, src);
         if (err && !ret)
@@ -1010,7 +1037,6 @@ int btrfs_del_qgroup_relation(struct btrfs_trans_handle *trans,
 
         spin_lock(&fs_info->qgroup_lock);
         del_relation_rb(fs_info, src, dst);
-
         spin_unlock(&fs_info->qgroup_lock);
 out:
         mutex_unlock(&fs_info->qgroup_ioctl_lock);
@@ -1030,8 +1056,15 @@ int btrfs_create_qgroup(struct btrfs_trans_handle *trans,
                 ret = -EINVAL;
                 goto out;
         }
+        qgroup = find_qgroup_rb(fs_info, qgroupid);
+        if (qgroup) {
+                ret = -EEXIST;
+                goto out;
+        }
 
         ret = add_qgroup_item(trans, quota_root, qgroupid);
+        if (ret)
+                goto out;
 
         spin_lock(&fs_info->qgroup_lock);
         qgroup = add_qgroup_rb(fs_info, qgroupid);
@@ -1058,15 +1091,18 @@ int btrfs_remove_qgroup(struct btrfs_trans_handle *trans,
                 goto out;
         }
 
-        /* check if there are no relations to this qgroup */
         qgroup = find_qgroup_rb(fs_info, qgroupid);
-        if (qgroup) {
-                if (!list_empty(&qgroup->groups) || !list_empty(&qgroup->members)) {
+        if (!qgroup) {
+                ret = -ENOENT;
+                goto out;
+        } else {
+                /* check if there are no relations to this qgroup */
+                if (!list_empty(&qgroup->groups) ||
+                    !list_empty(&qgroup->members)) {
                         ret = -EBUSY;
                         goto out;
                 }
         }
-
         ret = del_qgroup_item(trans, quota_root, qgroupid);
 
         spin_lock(&fs_info->qgroup_lock);