Btrfs: set qgroup_ulist to be null after calling ulist_free()

We call ulist_free(qgroup_ulist) in btrfs_free_qgroup_config(), and btrfs_free_qgroup_config() may be called in two cases: (1)umount filesystem (2)disabling quota However, if we firstly disable quota and then umount filesystem, a double free happens. Fix it. Signed-off-by: Wang Shilong <[email protected]> Signed-off-by: Josef Bacik <[email protected]> Signed-off-by: Chris Mason <[email protected]>
niw · Sep 1, 2013 · 1e7bac1 · 1e7bac1
1 parent 647f63b
commit 1e7bac1
Showing 1 changed file with 6 additions and 0 deletions.
diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c
@@ -460,7 +460,13 @@ void btrfs_free_qgroup_config(struct btrfs_fs_info *fs_info)
 		}
 		kfree(qgroup);
 	}
+	/*
+	 * we call btrfs_free_qgroup_config() when umounting
+	 * filesystem and disabling quota, so we set qgroup_ulit
+	 * to be null here to avoid double free.
+	 */
 	ulist_free(fs_info->qgroup_ulist);
+	fs_info->qgroup_ulist = NULL;
 }
 
 static int add_qgroup_relation_item(struct btrfs_trans_handle *trans,