imsm: validate multiple ppls during assemble

Change validation algorithm to check validity of multiple ppls that
are stored in PPL area.

If read error occurs during - treat the all PPLs as invalid -
there is no guarantee that this one was not latest. If the header CRC is
incorrect - assume that there are no further PPLs in PPL area.

If whole PPL area was written at least once - there is a possibility that
old PPL (with lower generation number) will follow the recent one
(with higest generation number). Compare those generation numbers to check
which PPL is latest.

Signed-off-by: Pawel Baldysiak <pawel.baldysiak@intel.com>
Signed-off-by: Jes Sorensen <jsorensen@fb.com>

diff --git a/super-intel.c b/super-intel.c
index 347838e7549d25c18b006e516e0e04634d079b7a..56dec365b86a59109090513fbedcc68a8b5c5a09 100644 (file)
--- a/super-intel.c
+++ b/super-intel.c
@@ -6106,11 +6106,14 @@ static int validate_ppl_imsm(struct supertype *st, struct mdinfo *info,
        struct imsm_dev *dev;
        struct imsm_map *map;
        __u32 idx;
+       unsigned int i;
+       unsigned long long ppl_offset = 0;
+       unsigned long long prev_gen_num = 0;
 
        if (disk->disk.raid_disk < 0)
                return 0;
 
-       if (posix_memalign(&buf, 4096, PPL_HEADER_SIZE)) {
+       if (posix_memalign(&buf, MAX_SECTOR_SIZE, PPL_HEADER_SIZE)) {
                pr_err("Failed to allocate PPL header buffer\n");
                return -1;
        }
@@ -6123,34 +6126,54 @@ static int validate_ppl_imsm(struct supertype *st, struct mdinfo *info,
        if (!d || d->index < 0 || is_failed(&d->disk))
                goto out;
 
-       if (lseek64(d->fd, info->ppl_sector * 512, SEEK_SET) < 0) {
-               perror("Failed to seek to PPL header location");
-               ret = -1;
-               goto out;
-       }
+       ret = 1;
+       while (ppl_offset < MULTIPLE_PPL_AREA_SIZE_IMSM) {
+               dprintf("Checking potential PPL at offset: %llu\n", ppl_offset);
 
-       if (read(d->fd, buf, PPL_HEADER_SIZE) != PPL_HEADER_SIZE) {
-               perror("Read PPL header failed");
-               ret = -1;
-               goto out;
-       }
+               if (lseek64(d->fd, info->ppl_sector * 512 + ppl_offset,
+                           SEEK_SET) < 0) {
+                       perror("Failed to seek to PPL header location");
+                       ret = -1;
+                       goto out;
+               }
 
-       ppl_hdr = buf;
+               if (read(d->fd, buf, PPL_HEADER_SIZE) != PPL_HEADER_SIZE) {
+                       perror("Read PPL header failed");
+                       ret = -1;
+                       goto out;
+               }
 
-       crc = __le32_to_cpu(ppl_hdr->checksum);
-       ppl_hdr->checksum = 0;
+               ppl_hdr = buf;
 
-       if (crc != ~crc32c_le(~0, buf, PPL_HEADER_SIZE)) {
-               dprintf("Wrong PPL header checksum on %s\n",
-                       d->devname);
-               ret = 1;
-       }
+               crc = __le32_to_cpu(ppl_hdr->checksum);
+               ppl_hdr->checksum = 0;
+
+               if (crc != ~crc32c_le(~0, buf, PPL_HEADER_SIZE)) {
+                       dprintf("Wrong PPL header checksum on %s\n",
+                               d->devname);
+                       goto out;
+               }
+
+               if (prev_gen_num > __le64_to_cpu(ppl_hdr->generation)) {
+                       /* previous was newest, it was already checked */
+                       goto out;
+               }
+
+               if ((__le32_to_cpu(ppl_hdr->signature) !=
+                             super->anchor->orig_family_num)) {
+                       dprintf("Wrong PPL header signature on %s\n",
+                               d->devname);
+                       ret = 1;
+                       goto out;
+               }
+
+               ret = 0;
+               prev_gen_num = __le64_to_cpu(ppl_hdr->generation);
 
-       if (!ret && (__le32_to_cpu(ppl_hdr->signature) !=
-                     super->anchor->orig_family_num)) {
-               dprintf("Wrong PPL header signature on %s\n",
-                       d->devname);
-               ret = 1;
+               ppl_offset += PPL_HEADER_SIZE;
+               for (i = 0; i < __le32_to_cpu(ppl_hdr->entries_count); i++)
+                       ppl_offset +=
+                                  __le32_to_cpu(ppl_hdr->entries[i].pp_size);
        }
 
 out: