void btrfs_wait_block_group_cache_progress(struct btrfs_block_group *cache,
u64 num_bytes);
int btrfs_cache_block_group(struct btrfs_block_group *cache, bool wait);
-void btrfs_put_caching_control(struct btrfs_caching_control *ctl);
struct btrfs_caching_control *btrfs_get_caching_control(
struct btrfs_block_group *cache);
int btrfs_add_new_free_space(struct btrfs_block_group *block_group,