On Fri, Jan 05, 2018 at 11:15:39AM -0600, Tony Asleson wrote:
> +static int stratis_valid_sb(blkid_probe pr, uint8_t *p)
> +{
> + const struct stratis_sb *stratis = (const struct stratis_sb *)p;
> + uint32_t crc = 0;
> +
> + // generate CRC from byte position 4 for length 508 == 512 byte sector
> + crc = crc32c(~0L, p + sizeof(stratis->crc32),
> + BS - sizeof(stratis->crc32));
> + crc ^= ~0L;
> +
> + return blkid_probe_verify_csum(pr, crc, le32_to_cpu(stratis->crc32));
Not sure that blkid_probe_verify_csum() is a good idea for your
use-case.
The function ignores (returns 1) bad checksums if BLKID_SUBLKS_BADCSUM
flag is enabled. I guess you want to use second (backup) superblock
if the primary one is broken. It would be better to use
return crc == le32_to_cpu(stratis->crc32);
and do not use blkid_probe_verify_csum() at all.
> +static int probe_stratis(blkid_probe pr,
> + const struct blkid_idmag *mag __attribute__((__unused__)))
> +{
> + const struct stratis_sb *stratis = NULL;
> + uint8_t *buf = blkid_probe_get_buffer(pr, 0, SB_AREA_SIZE);
> +
> + if (!buf)
> + return errno ? -errno : 1;
> +
> + if (stratis_valid_sb(pr, buf + FIRST_COPY_OFFSET)) {
> + stratis = (const struct stratis_sb *)(buf + FIRST_COPY_OFFSET);
> + } else {
> + if (!stratis_valid_sb(pr, buf + SECOND_COPY_OFFSET))
> + return 1;
> +
> + stratis = (const struct stratis_sb *)
> + (buf + SECOND_COPY_OFFSET);
> + }
> +
> + blkid_probe_strncpy_uuid(pr, (unsigned char *)stratis->dev_uuid,
> + sizeof(stratis->dev_uuid));
> + blkid_probe_set_value(pr, "POOL_UUID",
> + (unsigned char *)stratis->pool_uuid,
> + sizeof(stratis->pool_uuid));
> +
> + blkid_probe_sprintf_value(pr, "SECTORS", "%" PRIu64, stratis->sectors);
Hmm... SECTORS sounds pretty generic. Don't forget it will be
stored in udevd db. Would be possible to use any prefix?
For example:
POOL_SECTORS
> + blkid_probe_sprintf_value(pr, "INITIALIZATION_TIME", "%" PRIu64,
> + stratis->initialization_time);
POOL_INITTIME
Karel
--
Karel Zak <kzak@xxxxxxxxxx>
http://karelzak.blogspot.com
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