Re: [PATCH v7 04/10] qcow2: Support BDRV_REQ_ZERO_WRITE for truncate

[Eric Blake]

On 4/24/20 7:54 AM, Kevin Wolf wrote:
> If BDRV_REQ_ZERO_WRITE is set and we're extending the image, calling
> qcow2_cluster_zeroize() with flags=0 does the right thing: It doesn't
> undo any previous preallocation, but just adds the zero flag to all
> relevant L2 entries. If an external data file is in use, a write_zeroes
> request to the data file is made instead.
>
> Signed-off-by: Kevin Wolf <address@hidden>
> ---
>   block/qcow2-cluster.c |  2 +-
>   block/qcow2.c         | 34 ++++++++++++++++++++++++++++++++++
>   2 files changed, 35 insertions(+), 1 deletion(-)

Reviewed-by: Eric Blake <address@hidden>

--
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
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