Re: [PATCH 6/9] parallels: Move check of cluster outside image to a separate function

From: "Denis V. Lunev" <den@virtuozzo.com>
To: Alexander Ivanov <alexander.ivanov@virtuozzo.com>, qemu-devel@nongnu.org
Cc: qemu-block@nongnu.org, stefanha@redhat.com,
	vsementsov@yandex-team.ru, kwolf@redhat.com, hreitz@redhat.com
Subject: Re: [PATCH 6/9] parallels: Move check of cluster outside image to a separate function
Date: Fri, 19 Aug 2022 14:56:48 +0200	[thread overview]
Message-ID: <582f5f97-1307-dd98-c147-993c37fe96a3@virtuozzo.com> (raw)
In-Reply-To: <20220818151456.2118470-7-alexander.ivanov@virtuozzo.com>

On 18.08.2022 17:14, Alexander Ivanov wrote:
> We will add more and more checks so we need a better code structure
> in parallels_co_check. Let each check performs in a separate loop
> in a separate helper.
> s->data_end fix relates to out-of-image check so move it
> to the helper too.
>
> Signed-off-by: Alexander Ivanov <alexander.ivanov@virtuozzo.com>
> ---
>   block/parallels.c | 67 +++++++++++++++++++++++++++++++----------------
>   1 file changed, 45 insertions(+), 22 deletions(-)
>
> diff --git a/block/parallels.c b/block/parallels.c
> index 3900a0f4a9..1c7626c867 100644
> --- a/block/parallels.c
> +++ b/block/parallels.c
> @@ -438,6 +438,46 @@ static void parallels_check_unclean(BlockDriverState *bs,
>       }
>   }
>   
> +static int parallels_check_outside_image(BlockDriverState *bs,
> +                                         BdrvCheckResult *res,
> +                                         BdrvCheckMode fix)
> +{
> +    BDRVParallelsState *s = bs->opaque;
> +    uint32_t i;
> +    int64_t off, size;
> +
> +    size = bdrv_getlength(bs->file->bs);
> +    if (size < 0) {
> +        res->check_errors++;
> +        return size;
> +    }
> +
> +    for (i = 0; i < s->bat_size; i++) {
> +        off = bat2sect(s, i) << BDRV_SECTOR_BITS;
> +        if (off > size) {
> +            fprintf(stderr, "%s cluster %u is outside image\n",
> +                    fix & BDRV_FIX_ERRORS ? "Repairing" : "ERROR", i);
> +            res->corruptions++;
> +            if (fix & BDRV_FIX_ERRORS) {
> +                parallels_set_bat_entry(s, i, 0);
> +                res->corruptions_fixed++;
> +            }
> +        }
> +    }
> +
> +    /*
> +     * If there were an out-of-image cluster it would be repaired,
> +     * but s->data_end still would point outside image.
> +     * Fix s->data_end by the file size.
> +     */
> +    size >>= BDRV_SECTOR_BITS;
> +    if (s->data_end > size) {
> +        s->data_end = size;
> +    }
and this is incorrect IMHO. In the next patch you could truncate the file
inside leak check and thus data_end will point to a wrong too lengthy
value.


> +
> +    return 0;
> +}
> +
>   static int coroutine_fn parallels_co_check(BlockDriverState *bs,
>                                              BdrvCheckResult *res,
>                                              BdrvCheckMode fix)
> @@ -457,6 +497,11 @@ static int coroutine_fn parallels_co_check(BlockDriverState *bs,
>   
>       parallels_check_unclean(bs, res, fix);
>   
> +    ret = parallels_check_outside_image(bs, res, fix);
> +    if (ret < 0) {
> +        goto out;
> +    }
> +
>       res->bfi.total_clusters = s->bat_size;
>       res->bfi.compressed_clusters = 0; /* compression is not supported */
>   
> @@ -469,19 +514,6 @@ static int coroutine_fn parallels_co_check(BlockDriverState *bs,
>               continue;
>           }
>   
> -        /* cluster outside the image */
> -        if (off > size) {
> -            fprintf(stderr, "%s cluster %u is outside image\n",
> -                    fix & BDRV_FIX_ERRORS ? "Repairing" : "ERROR", i);
> -            res->corruptions++;
> -            if (fix & BDRV_FIX_ERRORS) {
> -                prev_off = 0;
> -                parallels_set_bat_entry(s, i, 0);
> -                res->corruptions_fixed++;
> -                continue;
> -            }
> -        }
> -
>           res->bfi.allocated_clusters++;
>           if (off > high_off) {
>               high_off = off;
> @@ -518,15 +550,6 @@ static int coroutine_fn parallels_co_check(BlockDriverState *bs,
>               res->leaks_fixed += count;
>           }
>       }
> -    /*
> -     * If there were an out-of-image cluster it would be repaired,
> -     * but s->data_end still would point outside image.
> -     * Fix s->data_end by the file size.
> -     */
> -    size >>= BDRV_SECTOR_BITS;
> -    if (s->data_end > size) {
> -        s->data_end = size;
> -    }
>   out:
>       qemu_co_mutex_unlock(&s->lock);
>