static struct btrfs_lockdep_keyset {
        u64                     id;             /* root objectid */
-       /* Longest entry: btrfs-free-space-00 */
-       char                    names[BTRFS_MAX_LEVEL][20];
+       /* Longest entry: btrfs-block-group-00 */
+       char                    names[BTRFS_MAX_LEVEL][24];
        struct lock_class_key   keys[BTRFS_MAX_LEVEL];
 } btrfs_lockdep_keysets[] = {
        { .id = BTRFS_ROOT_TREE_OBJECTID,       DEFINE_NAME("root")     },
        { .id = BTRFS_DATA_RELOC_TREE_OBJECTID, DEFINE_NAME("dreloc")   },
        { .id = BTRFS_UUID_TREE_OBJECTID,       DEFINE_NAME("uuid")     },
        { .id = BTRFS_FREE_SPACE_TREE_OBJECTID, DEFINE_NAME("free-space") },
+       { .id = BTRFS_BLOCK_GROUP_TREE_OBJECTID, DEFINE_NAME("block-group") },
        { .id = 0,                              DEFINE_NAME("tree")     },
 };