Re: [Qemu-devel] [PATCH] qcow2: Fix qcow2_make_empty() with external data file

[Eric Blake <eblake@redhat.com>]

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On 4/29/19 6:21 AM, Kevin Wolf wrote:
> Am 29.04.2019 um 12:57 hat Kevin Wolf geschrieben:
>> make_completely_empty() is an optimisated path for bdrv_make_empty()
>> where completely new metadata is created inside the image file instead
>> of going through all clusters and discarding them. For an external data
>> file, however, we actually need to do discard operations on the data
>> file; just overwriting the qcow2 file doesn't get rid of the data.
>>
>> The necessary slow path with an explicit discard operation already
>> exists for other cases. Use it for external data files, too.
>>
>> Cc: qemu-stable@nongnu.org
>> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
>> ---
>>  block/qcow2.c | 3 ++-
>>  1 file changed, 2 insertions(+), 1 deletion(-)

> Oops, I hadn't everything committed yet. I'll add a comment change as
> well:

With the comment change squashed in,
Reviewed-by: Eric Blake <eblake@redhat.com>


-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
Virtualization:  qemu.org | libvirt.org


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