btrfs_init_work
void btrfs_init_work(struct btrfs_work *work, btrfs_func_t func,
btrfs_init_work(&async->work, run_one_async_start, run_one_async_done);
btrfs_init_work(&caching_ctl->work, caching_thread, NULL);
btrfs_init_work(&async_work->work, btrfs_async_run_delayed_root, NULL);
btrfs_init_work(&async_chunk[i].work, compress_file_range,
btrfs_init_work(&work->work, btrfs_run_delalloc_work, NULL);
btrfs_init_work(&ordered->work, finish_ordered_fn, NULL);
btrfs_init_work(&ordered->flush_work,
btrfs_init_work(&fs_info->qgroup_rescan_work,