Re: [PATCH v4 10/18] block/io: introduce block driver snapshot-access API

[Hanna Reitz]

On 16.02.22 20:46, Vladimir Sementsov-Ogievskiy wrote:
> Add new block driver handlers and corresponding generic wrappers.
> It will be used to allow copy-before-write filter to provide
> reach fleecing interface in further commit.
>
> In future this approach may be used to allow reading qcow2 interanal

(s/interanal/internal/)

> snaphots, for example to export them through NBD.

Ooh, that’s indeed quite nice.

Raises the question of how users are to select a specific snapshot in 
qcow2 file, but your next patch answers that question: The snapshot 
access driver is to receive a runtime option for this, and the API is to 
be extended to allow for selecting a specific snapshot.  Sounds good!

> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
> ---
>   include/block/block_int.h | 27 +++++++++++++++
>   block/io.c                | 69 +++++++++++++++++++++++++++++++++++++++
>   2 files changed, 96 insertions(+)

Yes, really nice.  Thanks.

Reviewed-by: Hanna Reitz <hreitz@redhat.com>