read_gpt
static int read_gpt(daddr_t, struct gpt_hdr *);
read_gpt(GPT_HDR_BLKNO, &gpt1);
read_gpt(disksectors - 1, &gpt2);
if (read_gpt(&raidframe, rf_offset, rf_size) != 0) {
error = read_gpt(d, offset, size);