Re: [Qemu-devel] [PATCH 15/18] qapi: add md5 checksum of last dirty bitmap level to query-block

["Daniel P. Berrange" <berrange@redhat.com>]

On Tue, Aug 16, 2016 at 01:26:12PM +0300, Vladimir Sementsov-Ogievskiy wrote:
> Reviewed-by: John Snow <jsnow@redhat.com>
> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
> ---
>  block/dirty-bitmap.c   | 1 +
>  include/qemu/hbitmap.h | 8 ++++++++
>  qapi/block-core.json   | 5 ++++-
>  util/hbitmap.c         | 8 ++++++++
>  4 files changed, 21 insertions(+), 1 deletion(-)
> 
> diff --git a/block/dirty-bitmap.c b/block/dirty-bitmap.c
> index 32aa6eb..f895fce 100644
> --- a/block/dirty-bitmap.c
> +++ b/block/dirty-bitmap.c
> @@ -365,6 +365,7 @@ BlockDirtyInfoList *bdrv_query_dirty_bitmaps(BlockDriverState *bs)
>          info->has_name = !!bm->name;
>          info->name = g_strdup(bm->name);
>          info->status = bdrv_dirty_bitmap_status(bm);
> +        info->md5 = hbitmap_md5(bm->bitmap);
>          entry->value = info;
>          *plist = entry;
>          plist = &entry->next;
> diff --git a/include/qemu/hbitmap.h b/include/qemu/hbitmap.h
> index eb46475..8d4f836 100644
> --- a/include/qemu/hbitmap.h
> +++ b/include/qemu/hbitmap.h
> @@ -225,6 +225,14 @@ void hbitmap_deserialize_zeroes(HBitmap *hb, uint64_t start, uint64_t count,
>  void hbitmap_deserialize_finish(HBitmap *hb);
>  
>  /**
> + * hbitmap_md5:
> + * @bitmap: HBitmap to operate on.
> + *
> + * Returns md5 checksum of the last level.
> + */
> +char *hbitmap_md5(const HBitmap *bitmap);
> +
> +/**
>   * hbitmap_free:
>   * @hb: HBitmap to operate on.
>   *
> diff --git a/qapi/block-core.json b/qapi/block-core.json
> index 2bbc027..5642a8a 100644
> --- a/qapi/block-core.json
> +++ b/qapi/block-core.json
> @@ -419,11 +419,14 @@
>  #
>  # @status: current status of the dirty bitmap (since 2.4)
>  #
> +# @md5: md5 checksum (as a hexadecimal string) of the last bitmap level
> +#       (since 2.6)
> +#
>  # Since: 1.3
>  ##
>  { 'struct': 'BlockDirtyInfo',
>    'data': {'*name': 'str', 'count': 'int', 'granularity': 'uint32',
> -           'status': 'DirtyBitmapStatus'} }
> +           'status': 'DirtyBitmapStatus', 'md5': 'str'} }
>  
>  ##
>  # @BlockInfo:
> diff --git a/util/hbitmap.c b/util/hbitmap.c
> index 6a13c12..4afb3d5 100644
> --- a/util/hbitmap.c
> +++ b/util/hbitmap.c
> @@ -669,3 +669,11 @@ void hbitmap_free_meta(HBitmap *hb)
>      hbitmap_free(hb->meta);
>      hb->meta = NULL;
>  }
> +
> +char *hbitmap_md5(const HBitmap *bitmap)
> +{
> +    uint64_t size =
> +        MAX((bitmap->size + BITS_PER_LONG - 1) >> BITS_PER_LEVEL, 1);
> +    const guchar *data = (const guchar *)bitmap->levels[HBITMAP_LEVELS - 1];
> +    return g_compute_checksum_for_data(G_CHECKSUM_MD5, data, size);
> +}

Please use one of the qcrypto_hash_* functions, not GChecksum directly,
as this ensures we use the hash impls that have been through crypto
certification when needed by people shipping QEM.


Regards,
Daniel
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