Re: [PATCH v2 10/10] qcow2-refcount: check_refblocks(): add separate message for reserved

[Kirill Tkhai]

On 05.05.2021 09:59, Vladimir Sementsov-Ogievskiy wrote:
> Split checking for reserved bits out of aligned offset check.
> 
> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
> Reviewed-by: Eric Blake <eblake@redhat.com>

Tested-by: Kirill Tkhai <ktkhai@virtuozzo.com>

> ---
>  block/qcow2.h          |  1 +
>  block/qcow2-refcount.c | 10 +++++++++-
>  2 files changed, 10 insertions(+), 1 deletion(-)
> 
> diff --git a/block/qcow2.h b/block/qcow2.h
> index 58fd7f1678..fd48a89d45 100644
> --- a/block/qcow2.h
> +++ b/block/qcow2.h
> @@ -591,6 +591,7 @@ typedef enum QCow2MetadataOverlap {
>  #define L2E_STD_RESERVED_MASK 0x3f000000000001feULL
>  
>  #define REFT_OFFSET_MASK 0xfffffffffffffe00ULL
> +#define REFT_RESERVED_MASK 0x1ffULL
>  
>  #define INV_OFFSET (-1ULL)
>  
> diff --git a/block/qcow2-refcount.c b/block/qcow2-refcount.c
> index 15c4f6b075..472a7026db 100644
> --- a/block/qcow2-refcount.c
> +++ b/block/qcow2-refcount.c
> @@ -2091,9 +2091,17 @@ static int check_refblocks(BlockDriverState *bs, 
> BdrvCheckResult *res,
>  
>      for(i = 0; i < s->refcount_table_size; i++) {
>          uint64_t offset, cluster;
> -        offset = s->refcount_table[i];
> +        offset = s->refcount_table[i] & REFT_OFFSET_MASK;
>          cluster = offset >> s->cluster_bits;
>  
> +        if (s->refcount_table[i] & REFT_RESERVED_MASK) {
> +            fprintf(stderr, "ERROR refcount table entry %" PRId64 " has "
> +                    "reserved bits set\n", i);
> +            res->corruptions++;
> +            *rebuild = true;
> +            continue;
> +        }
> +
>          /* Refcount blocks are cluster aligned */
>          if (offset_into_cluster(s, offset)) {
>              fprintf(stderr, "ERROR refcount block %" PRId64 " is not "
>