u64 bio_offset, void *private_data,
extent_submit_bio_hook_t *submit_bio_start,
extent_submit_bio_hook_t *submit_bio_done);
-unsigned long btrfs_async_submit_limit(struct btrfs_fs_info *info);
int btrfs_write_tree_block(struct extent_buffer *buf);
void btrfs_wait_tree_block_writeback(struct extent_buffer *buf);
int btrfs_init_log_root_tree(struct btrfs_trans_handle *trans,