udf_read_phys
error1 = udf_read_phys(vds1_buf, layout.vds1, layout.vds1_size);
error2 = udf_read_phys(vds2_buf, layout.vds2, layout.vds2_size);
error = udf_read_phys(data, phys, ext);
error = udf_read_phys(pos, sector + 1, sectors-1);
extern int udf_read_phys(void *blob, uint32_t location, uint32_t sects);