disk: part_efi: add support to repair gpt table

If a gpt table is corrupted (after a power cut
for example), then the gpt table should repaired.
The function gpt_repair_headers check if at least
one gpt table is valid, and then only write the
corrupted gpt table.

Signed-off-by: Philippe Reynes <philippe.reynes@softathome.com>
This commit is contained in:
Philippe Reynes 2022-04-22 17:46:48 +02:00 committed by Tom Rini
parent 145921bdbd
commit 5c783b54d6
2 changed files with 96 additions and 0 deletions

View File

@ -705,6 +705,92 @@ int gpt_verify_headers(struct blk_desc *dev_desc, gpt_header *gpt_head,
return 0;
}
static void restore_primary_gpt_header(gpt_header *gpt_h, struct blk_desc *dev_desc)
{
u32 calc_crc32;
u64 val;
/* recalculate the values for the Primary GPT Header */
val = le64_to_cpu(gpt_h->my_lba);
gpt_h->my_lba = gpt_h->alternate_lba;
gpt_h->alternate_lba = cpu_to_le64(val);
gpt_h->partition_entry_lba = cpu_to_le64(partition_entries_offset(dev_desc));
gpt_h->header_crc32 = 0;
calc_crc32 = efi_crc32((const unsigned char *)gpt_h,
le32_to_cpu(gpt_h->header_size));
gpt_h->header_crc32 = cpu_to_le32(calc_crc32);
}
static int write_one_gpt_table(struct blk_desc *dev_desc,
gpt_header *gpt_h, gpt_entry *gpt_e)
{
const int pte_blk_cnt = BLOCK_CNT((gpt_h->num_partition_entries
* sizeof(gpt_entry)), dev_desc);
lbaint_t start;
int ret = 0;
start = le64_to_cpu(gpt_h->my_lba);
if (blk_dwrite(dev_desc, start, 1, gpt_h) != 1) {
ret = -1;
goto out;
}
start = le64_to_cpu(gpt_h->partition_entry_lba);
if (blk_dwrite(dev_desc, start, pte_blk_cnt, gpt_e) != pte_blk_cnt) {
ret = -1;
goto out;
}
out:
return ret;
}
int gpt_repair_headers(struct blk_desc *dev_desc)
{
ALLOC_CACHE_ALIGN_BUFFER_PAD(gpt_header, gpt_h1, 1, dev_desc->blksz);
ALLOC_CACHE_ALIGN_BUFFER_PAD(gpt_header, gpt_h2, 1, dev_desc->blksz);
gpt_entry *gpt_e1 = NULL, *gpt_e2 = NULL;
int is_gpt1_valid, is_gpt2_valid;
int ret = -1;
is_gpt1_valid = is_gpt_valid(dev_desc, GPT_PRIMARY_PARTITION_TABLE_LBA,
gpt_h1, &gpt_e1);
is_gpt2_valid = is_gpt_valid(dev_desc, dev_desc->lba - 1,
gpt_h2, &gpt_e2);
if (is_gpt1_valid && is_gpt2_valid) {
ret = 0;
goto out;
}
if (is_gpt1_valid && !is_gpt2_valid) {
prepare_backup_gpt_header(gpt_h1);
ret = write_one_gpt_table(dev_desc, gpt_h1, gpt_e1);
goto out;
}
if (!is_gpt1_valid && is_gpt2_valid) {
restore_primary_gpt_header(gpt_h2, dev_desc);
ret = write_one_gpt_table(dev_desc, gpt_h2, gpt_e2);
goto out;
}
if (!is_gpt1_valid && !is_gpt2_valid) {
ret = -1;
goto out;
}
out:
if (is_gpt1_valid)
free(gpt_e1);
if (is_gpt2_valid)
free(gpt_e2);
return ret;
}
int gpt_verify_partitions(struct blk_desc *dev_desc,
struct disk_partition *partitions, int parts,
gpt_header *gpt_head, gpt_entry **gpt_pte)

View File

@ -466,6 +466,16 @@ int write_mbr_and_gpt_partitions(struct blk_desc *dev_desc, void *buf);
int gpt_verify_headers(struct blk_desc *dev_desc, gpt_header *gpt_head,
gpt_entry **gpt_pte);
/**
* gpt_repair_headers() - Function to repair the GPT's header
* and partition table entries (PTE)
*
* @param dev_desc - block device descriptor
*
* Return: - '0' on success, otherwise error
*/
int gpt_repair_headers(struct blk_desc *dev_desc);
/**
* gpt_verify_partitions() - Function to check if partitions' name, start and
* size correspond to '$partitions' env variable