Re: [Qemu-devel] [PATCH v6 for 2.1 04/10] block: make 'top' argument to block-commit optional

[Eric Blake <eblake@redhat.com>]

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On 06/17/2014 04:25 PM, Eric Blake wrote:
> On 06/17/2014 03:53 PM, Jeff Cody wrote:
>> Now that active layer block-commit is supported, the 'top' argument
>> no longer needs to be mandatory.
>>
>> Change it to optional, with the default being the active layer in the
>> device chain.
>>
>> Reviewed-by: Eric Blake <eblake@redhat.com>
>> Reviewed-by: Benoit Canet <benoit@irqsave.net>
>> Signed-off-by: Jeff Cody <jcody@redhat.com>
>> ---
> 
> As mentioned elsewhere, this is the patch that changed from v5.  But so
> there's no confusion, I've gone back over this one, and my R-b still stands.
> 
>> +    /* Important Note:
>> +     *  libvirt relies on the DeviceNotFound error class in order to probe for
>> +     *  live commit feature versions; for this to work, we must make sure to
>> +     *  perform the device lookup before any generic errors that may occur in a
>> +     *  scenario in which all optional arguments are omitted. */
>>      bs = bdrv_find(device);
>>      if (!bs) {
>>          error_set(errp, QERR_DEVICE_NOT_FOUND, device);
> 
> Thanks for adding the comment :)
> 

Should we split this into a different series, since it is
non-controversial (unrelated to the rest of the series' impact on
child-node op-blockers), and useful for libvirt to turn on active
commit?  The rest of the series lets libvirt turn on relative backing
chain work, but we might as well get the easy part into the tree now.

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


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