[dm-devel] [PATCH] dm-integrity: count failures

[Milan Broz]

On 07/21/2017 06:00 PM, Mikulas Patocka wrote:
> This is a patch to count errors in dm-integrity - as Jon suggested.
> 
> This patch changes dm-integrity so that it counts the number of checksum
> failures and reports the counter in the status line.

Please increase minor target version when adding such table/status feature.

I see it is queued for the next kernel so still possibility to fix it.
(You will save me another hack in libcryptsetup when detecting
availability of this feature :-)

Thanks!
Milan


> 
> Signed-off-by: Mikulas Patocka <mpatocka at redhat.com>
> 
> ---
>  drivers/md/dm-integrity.c |    8 +++++++-
>  1 file changed, 7 insertions(+), 1 deletion(-)
> 
> Index: linux-2.6/drivers/md/dm-integrity.c
> ===================================================================
> --- linux-2.6.orig/drivers/md/dm-integrity.c
> +++ linux-2.6/drivers/md/dm-integrity.c
> @@ -225,6 +225,8 @@ struct dm_integrity_c {
>  	struct alg_spec internal_hash_alg;
>  	struct alg_spec journal_crypt_alg;
>  	struct alg_spec journal_mac_alg;
> +
> +	atomic64_t number_of_mismatches;
>  };
>  
>  struct dm_integrity_range {
> @@ -309,6 +311,8 @@ static void dm_integrity_dtr(struct dm_t
>  
>  static void dm_integrity_io_error(struct dm_integrity_c *ic, const char *msg, int err)
>  {
> +	if (err == -EILSEQ)
> +		atomic64_inc(&ic->number_of_mismatches);
>  	if (!cmpxchg(&ic->failed, 0, err))
>  		DMERR("Error on %s: %d", msg, err);
>  }
> @@ -1273,6 +1277,7 @@ again:
>  					DMERR("Checksum failed at sector 0x%llx",
>  					      (unsigned long long)(sector - ((r + ic->tag_size - 1) / ic->tag_size)));
>  					r = -EILSEQ;
> +					atomic64_inc(&ic->number_of_mismatches);
>  				}
>  				if (likely(checksums != checksums_onstack))
>  					kfree(checksums);
> @@ -2222,7 +2227,7 @@ static void dm_integrity_status(struct d
>  
>  	switch (type) {
>  	case STATUSTYPE_INFO:
> -		result[0] = '\0';
> +		DMEMIT("%llu", (unsigned long long)atomic64_read(&ic->number_of_mismatches));
>  		break;
>  
>  	case STATUSTYPE_TABLE: {
> @@ -2795,6 +2800,7 @@ static int dm_integrity_ctr(struct dm_ta
>  	bio_list_init(&ic->flush_bio_list);
>  	init_waitqueue_head(&ic->copy_to_journal_wait);
>  	init_completion(&ic->crypto_backoff);
> +	atomic64_set(&ic->number_of_mismatches, 0);
>  
>  	r = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), &ic->dev);
>  	if (r) {
>