hammer_xlate_to_phys
buffer->raw_offset = hammer_xlate_to_phys(volume->ondisk, zone2_offset);
nbio->bio_offset = hammer_xlate_to_phys(volume->ondisk,
buf_offset = hammer_xlate_to_phys(volume->ondisk, zone2_offset);
nbio->bio_offset = hammer_xlate_to_phys(volume->ondisk,
phys_offset = hammer_xlate_to_phys(volume->ondisk, zone2_offset);
buffer->io.offset = hammer_xlate_to_phys(volume->ondisk, zone2_offset);