[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-devel] [PATCH v2] qcow2: Set zero flag for discarded clusters
From: |
Eric Blake |
Subject: |
Re: [Qemu-devel] [PATCH v2] qcow2: Set zero flag for discarded clusters |
Date: |
Mon, 17 Feb 2014 10:12:57 -0700 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.3.0 |
On 02/17/2014 07:45 AM, Kevin Wolf wrote:
> Instead of making the backing file contents visible again after a discard
> request, set the zero flag if possible (i.e. on version >= 3).
>
> Signed-off-by: Kevin Wolf <address@hidden>
> ---
> block/qcow2-cluster.c | 22 ++++++++++++++++++++--
> tests/qemu-iotests/046 | 18 ++++++++++++++----
> 2 files changed, 34 insertions(+), 6 deletions(-)
>
> + if (!!(old_offset & QCOW_OFLAG_ZERO)) {
The !! is not necessary here; any non-zero value in a boolean context
gives the same result as an explicit conversion to 0-or-1.
But as that's cosmetic, I'm okay whether you leave it as is or simplify
it, when adding:
Reviewed-by: Eric Blake <address@hidden>
--
Eric Blake eblake redhat com +1-919-301-3266
Libvirt virtualization library http://libvirt.org
signature.asc
Description: OpenPGP digital signature