| #val_type uint64_t | |
| BTRFS_ROOT_TREE_OBJECTID 1ULL | |
| BTRFS_EXTENT_TREE_OBJECTID 2ULL | |
| BTRFS_CHUNK_TREE_OBJECTID 3ULL | |
| BTRFS_DEV_TREE_OBJECTID 4ULL | |
| BTRFS_FS_TREE_OBJECTID 5ULL | |
| BTRFS_ROOT_TREE_DIR_OBJECTID 6ULL | |
| BTRFS_CSUM_TREE_OBJECTID 7ULL | |
| BTRFS_QUOTA_TREE_OBJECTID 8ULL | |
| BTRFS_UUID_TREE_OBJECTID 9ULL | |
| BTRFS_FREE_SPACE_TREE_OBJECTID 10ULL | |
| BTRFS_FIRST_FREE_OBJECTID 256ULL | |
| BTRFS_LAST_FREE_OBJECTID -256ULL | |
| UINT64_MAX -1ULL |