Btrfs: fix oops when writing dirty qgroups to disk

When disabling quota, we should clear out list 'dirty_qgroups',otherwise,
we will get oops if enabling quota again. Fix this by abstracting similar
code from del_qgroup_rb().

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

1 files changed, 13 insertions, 28 deletions

diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c
index 64a9e3cb9453..57b9805873f7 100644
--- a/fs/btrfs/qgroup.c
+++ b/fs/btrfs/qgroup.c
@@ -157,18 +157,11 @@ static struct btrfs_qgroup *add_qgroup_rb(struct btrfs_fs_info *fs_info,
         return qgroup;
 }
 
-/* must be called with qgroup_lock held */
-static int del_qgroup_rb(struct btrfs_fs_info *fs_info, u64 qgroupid)
+static void __del_qgroup_rb(struct btrfs_qgroup *qgroup)
 {
-        struct btrfs_qgroup *qgroup = find_qgroup_rb(fs_info, qgroupid);
         struct btrfs_qgroup_list *list;
 
-        if (!qgroup)
-                return -ENOENT;
-
-        rb_erase(&qgroup->node, &fs_info->qgroup_tree);
         list_del(&qgroup->dirty);
-
         while (!list_empty(&qgroup->groups)) {
                 list = list_first_entry(&qgroup->groups,
                                         struct btrfs_qgroup_list, next_group);
@@ -185,7 +178,18 @@ static int del_qgroup_rb(struct btrfs_fs_info *fs_info, u64 qgroupid)
                 kfree(list);
         }
         kfree(qgroup);
+}
 
+/* must be called with qgroup_lock held */
+static int del_qgroup_rb(struct btrfs_fs_info *fs_info, u64 qgroupid)
+{
+        struct btrfs_qgroup *qgroup = find_qgroup_rb(fs_info, qgroupid);
+
+        if (!qgroup)
+                return -ENOENT;
+
+        rb_erase(&qgroup->node, &fs_info->qgroup_tree);
+        __del_qgroup_rb(qgroup);
         return 0;
 }
 
@@ -435,30 +439,11 @@ void btrfs_free_qgroup_config(struct btrfs_fs_info *fs_info)
 {
         struct rb_node *n;
         struct btrfs_qgroup *qgroup;
-        struct btrfs_qgroup_list *list;
 
         while ((n = rb_first(&fs_info->qgroup_tree))) {
                 qgroup = rb_entry(n, struct btrfs_qgroup, node);
                 rb_erase(n, &fs_info->qgroup_tree);
-
-                while (!list_empty(&qgroup->groups)) {
-                        list = list_first_entry(&qgroup->groups,
-                                                struct btrfs_qgroup_list,
-                                                next_group);
-                        list_del(&list->next_group);
-                        list_del(&list->next_member);
-                        kfree(list);
-                }
-
-                while (!list_empty(&qgroup->members)) {
-                        list = list_first_entry(&qgroup->members,
-                                                struct btrfs_qgroup_list,
-                                                next_member);
-                        list_del(&list->next_group);
-                        list_del(&list->next_member);
-                        kfree(list);
-                }
-                kfree(qgroup);
+                __del_qgroup_rb(qgroup);
         }
         /*
          * we call btrfs_free_qgroup_config() when umounting