From 5c783b54d605aa21c8e3e0e188ab99d58135addd Mon Sep 17 00:00:00 2001 From: Philippe Reynes Date: Fri, 22 Apr 2022 17:46:48 +0200 Subject: 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 --- disk/part_efi.c | 86 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 86 insertions(+) (limited to 'disk') diff --git a/disk/part_efi.c b/disk/part_efi.c index f1f3e5bcef..829ccb6bd1 100644 --- a/disk/part_efi.c +++ b/disk/part_efi.c @@ -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) -- cgit v1.2.3