Re: [Qemu-block] [Qemu-devel] [RFC] QMP design: Fixing query-block and friends

[Markus Armbruster]

John Snow <address@hidden> writes:

> On 06/27/2017 12:31 PM, Kevin Wolf wrote:
>> Hi,
>> 
>> I haven't really liked query-block for a long time, but now that
>> blockdev-add and -blockdev have settled, it might finally be the time to
>> actually do something about it. In fact, if used together with these
>> modern interfaces, our query commands are simply broken, so we have to
>> fix something.
>> 
>
> [...words...]
>
>> 
>> So how do we go forward from here?
>> 
>> I guess we could add a few hacks o fix the really urgent things, and
>> just adding more information is always possible (at the cost of even
>> more duplication).
>> 
>
> I think you've included this suggestion so that you can summarily
> dismiss it as foolish.
>
>> However, it appears to me that I dislike so many thing about our current
>> query commands that I'm tempted to say: Throw it all away and start
>> over.
>> 
>
> Inclined to agree. The structure of the block layer has changed so much
> in the past few years and this is easily seen by the gap you've outlined
> here.
>
> We have to keep the old query commands around for a while as Eric says,
> but I worry that they are so wrong and misleading as to be actively harmful.
>
> Maybe there's some hair trigger somewhere that if $NEW_FEATURE_X is used
> to configure QEMU in some way, that the old commands can be deprecated
> at runtime, such that we can more aggressively force their retirement.

We warn on use of deprecated command line and HMP features.  I think we
want the same for QMP, within QMP.

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