udf_calc_vpart_freespace
udf_calc_vpart_freespace(ump, vpart_num, &freeblks);
udf_calc_vpart_freespace(ump, vpart_num, &freeblks);
udf_calc_vpart_freespace(ump, vpart_num, &freeblks);
udf_calc_vpart_freespace(ump, data_vpart_num, &data_free_lbs);
udf_calc_vpart_freespace(ump, meta_vpart_num, &meta_free_lbs);