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libfdisk: (gpt) move backup header after device resize 

Addresses: https://github.com/karelzak/util-linux/issues/532
Signed-off-by: Karel Zak <kzak@redhat.com>
This commit is contained in:
Karel Zak 2017-11-14 13:51:48 +01:00
parent 6e810fa59d
commit 9a8a3b88dc
1 changed files with 56 additions and 2 deletions
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58
libfdisk/src/gpt.c
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@ -525,6 +525,40 @@ static int gpt_mknew_pmbr(struct fdisk_context *cxt)
return 0;
}
/* Move backup header to the end of the device */
static void gpt_fix_alternative_lba(struct fdisk_context *cxt, struct fdisk_gpt_label *gpt)
{
struct gpt_header *p, *b;
uint64_t esz, esects, last;
if (!cxt)
return;
p = gpt->pheader; /* primary */
b = gpt->bheader; /* backup */
/* count size of partitions array */
esz = (uint64_t) le32_to_cpu(p->npartition_entries) * sizeof(struct gpt_entry);
esects = (esz + cxt->sector_size - 1) / cxt->sector_size;
/* reference from primary to backup */
p->alternative_lba = cpu_to_le64(cxt->total_sectors - 1ULL);
/* reference from backup to primary */
b->alternative_lba = p->my_lba;
b->my_lba = p->alternative_lba;
/* fix backup partitions array address */
b->partition_entry_lba = cpu_to_le64(cxt->total_sectors - 1ULL - esects);
/* update last usable LBA */
last = cxt->total_sectors - 2ULL - esects;
p->last_usable_lba = cpu_to_le64(last);
b->last_usable_lba = cpu_to_le64(last);
DBG(LABEL, ul_debug("Alternative-LBA updated to: %"PRIu64, le64_to_cpu(p->alternative_lba)));
}
/* some universal differences between the headers */
static void gpt_mknew_header_common(struct fdisk_context *cxt,
struct gpt_header *header, uint64_t lba)
@ -824,9 +858,15 @@ static int valid_pmbr(struct fdisk_context *cxt)
if (ret == GPT_MBR_PROTECTIVE) {
uint64_t sz_lba = (uint64_t) le32_to_cpu(pmbr->partition_record[part].size_in_lba);
if (sz_lba != cxt->total_sectors - 1ULL && sz_lba != 0xFFFFFFFFULL) {
fdisk_warnx(cxt, _("GPT PMBR size mismatch (%"PRIu64" != %"PRIu64") "
"will be corrected by w(rite)."),
"will be corrected by write."),
sz_lba, cxt->total_sectors - 1ULL);
/* Note that gpt_write_pmbr() overwrites PMBR, but we want to keep it valid already
* in memory too to disable warnings when valid_pmbr() called next time */
pmbr->partition_record[part].size_in_lba =
cpu_to_le32((uint32_t) min( cxt->total_sectors - 1ULL, 0xFFFFFFFFULL) );
fdisk_label_set_changed(cxt->label, 1);
}
}
@ -1525,6 +1565,7 @@ static int gpt_probe_label(struct fdisk_context *cxt)
if (!gpt->bheader)
goto failed;
gpt_recompute_crc(gpt->bheader, gpt->ents);
fdisk_label_set_changed(cxt->label, 1);
/* primary corrupted, backup OK -- recovery */
} else if (!gpt->pheader && gpt->bheader) {
@ -1534,6 +1575,20 @@ static int gpt_probe_label(struct fdisk_context *cxt)
if (!gpt->pheader)
goto failed;
gpt_recompute_crc(gpt->pheader, gpt->ents);
fdisk_label_set_changed(cxt->label, 1);
}
/* The headers make be correct, but Backup do not have to be on the end
* of the device (due to device resize, etc.). Let's fix this issue. */
if (le64_to_cpu(gpt->pheader->alternative_lba) > cxt->total_sectors ||
le64_to_cpu(gpt->pheader->alternative_lba) < cxt->total_sectors - 1ULL) {
fdisk_warnx(cxt, _("The backup GPT table is not on the end of the device. "
"This problem will be corrected by write."));
gpt_fix_alternative_lba(cxt, gpt);
gpt_recompute_crc(gpt->bheader, gpt->ents);
gpt_recompute_crc(gpt->pheader, gpt->ents);
fdisk_label_set_changed(cxt->label, 1);
}
cxt->label->nparts_max = gpt_get_nentries(gpt);
@ -1991,7 +2046,6 @@ static int gpt_write_disklabel(struct fdisk_context *cxt)
/* check that the backup header is properly placed */
if (le64_to_cpu(gpt->pheader->alternative_lba) < cxt->total_sectors - 1ULL)
/* TODO: correct this (with user authorization) and write */
goto err0;
if (check_overlap_partitions(gpt))