Re: [Qemu-devel] [PATCH V11 09/17] qmp: add interface query-snapshots

[Wenchao Xia <xiawenc@linux.vnet.ibm.com>]

于 2013-4-12 11:22, Eric Blake 写道:
> On 04/11/2013 09:17 PM, Wenchao Xia wrote:
>
>>>
>>>> Hmm, as I typed that, I did another search of qemu-schema.json - we have
>>>> the type 'ImageInfo' defined, but none of the existing 'command's ever
>>>> call out the use of that type.  Is it a type we are only using
>>>> internally to date, and where this is the first QMP command that would
>>>> actually expose SnapshotInfo or ImageInfo to a management app?  Then
>>>> maybe we _CAN_ modify SnapshotInfo, clean up all the internal code, and
>>>> provide a saner type for the first time that QMP can actually use it.
>>>
>>> IIRC, it's being used by qemu-img. As it's not trivial to determine if
>>> the field has users and as what goes in the schema is to be considered
>>> stable,
>>> it's better to keep the field. Instead, we could add a better field and
>>> deprecate the current one.
>>>
>>    I remember there is a patch laster year made "qemu-img info" dump out
>> json strings, where vm-clock-sec is dumped out.
>
> Ah, so it's not QMP exposing it, but qemu-info in JSON mode.  Still,
> changing that output to delete a field might break existing tools;
> adding a field might be safer, but then you'd have redundant information
> in the old style for old tools, as well as the added field.
>
   It seems keeping it, is what best we can do now. Markus, are you OK
with it?

-- 
Best Regards

Wenchao Xia