Re: [Qemu-devel] [PATCH v6 01/14] qcow2: Allow "full" discard

[Eric Blake]

On 04/29/2014 09:07 AM, Max Reitz wrote:
> Normally, discarded sectors should read back as zero. However, there are
> cases in which a sector (or rather cluster) should be discarded as if
> they were never written in the first place, that is, reading them should
> fall through to the backing file again.
> 
> Signed-off-by: Max Reitz <address@hidden>
> ---
>  block/qcow2-cluster.c  | 27 +++++++++++++++++----------
>  block/qcow2-snapshot.c |  2 +-
>  block/qcow2.c          |  2 +-
>  block/qcow2.h          |  2 +-
>  4 files changed, 20 insertions(+), 13 deletions(-)

> +         *
> +         * In case of full_discard being true, the sector should not be read
> +         * back as zeroes, but rather fall through to the backing file.

Maybe less awkward as:

If full_discard is true, the sector should not read back as zeroes, but
rather fall through to the backing file.

But minor enough that I'm okay with:

Reviewed-by: Eric Blake <address@hidden>

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org

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