[dm-devel] [PATCH] dm verity fec: fix hash block number in verity_fec_decode

[Sami Tolvanen]

On Thu, Apr 9, 2020 at 8:54 PM Sunwook Eom <speed.eom at samsung.com> wrote:
>
> The error correction data is computed as if data and hash blocks
> were concatenated. But hash block number is start from v->hash_start.
> So, we have to calculate hash block number based on that.
>
> Fixes: a739ff3f543af ("dm verity: add support for forward error correction")
> Signed-off-by: Sunwook Eom <speed.eom at samsung.com>
> ---
>   drivers/md/dm-verity-fec.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/md/dm-verity-fec.c b/drivers/md/dm-verity-fec.c
> index 49147e634046..fb41b4f23c48 100644
> --- a/drivers/md/dm-verity-fec.c
> +++ b/drivers/md/dm-verity-fec.c
> @@ -435,7 +435,7 @@ int verity_fec_decode(struct dm_verity *v, struct
> dm_verity_io *io,
>       fio->level++;
>
>       if (type == DM_VERITY_BLOCK_TYPE_METADATA)
> -        block += v->data_blocks;
> +        block = block - v->hash_start + v->data_blocks;
>
>       /*
>        * For RS(M, N), the continuous FEC data is divided into blocks of N

Thank you for the patch!

Reviewed-by: Sami Tolvanen <samitolvanen at google.com>

Sami