[dm-devel] [PATCH] dm-integrity: Do not check integrity for failed read operations

[Milan Broz]

On 07/31/2017 09:22 AM, Hyunchul Lee wrote:
> From: Hyunchul Lee <cheol.lee at lge.com>
> 
> Even though read operations fail, dm_integrity_map_continue()
> calls integrity_metadata() to check integrity. In this case,
> just complete these.

Yes this makes sense to me.

If bio->bi_status is set, it is directly propagated and the whole
bio is failed.

But this is just shortcut, the bio will fail the same way (with bi_status),
just integrity calculation code is skipped, so I think it should go to 4.13.

Thanks,
Milan

> 
> Signed-off-by: Hyunchul Lee <cheol.lee at lge.com>
> ---
>  drivers/md/dm-integrity.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/md/dm-integrity.c b/drivers/md/dm-integrity.c
> index 10f123e..f99eee9 100644
> --- a/drivers/md/dm-integrity.c
> +++ b/drivers/md/dm-integrity.c
> @@ -1697,7 +1697,11 @@ static void dm_integrity_map_continue(struct dm_integrity_io *dio, bool from_map
>  
>  	if (need_sync_io) {
>  		wait_for_completion_io(&read_comp);
> -		integrity_metadata(&dio->work);
> +		if (likely(!bio->bi_status))
> +			integrity_metadata(&dio->work);
> +		else
> +			dec_in_flight(dio);
> +
>  	} else {
>  		INIT_WORK(&dio->work, integrity_metadata);
>  		queue_work(ic->metadata_wq, &dio->work);
>