Re: [Qemu-devel] [RFC for-2.7 0/1] block/qapi: Add query-block-node-tree

[Max Reitz <mreitz@redhat.com>]

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On 29.03.2016 18:09, Kevin Wolf wrote:
> Am 29.03.2016 um 17:56 hat Max Reitz geschrieben:
>> On 29.03.2016 17:51, Kevin Wolf wrote:
>>> Am 24.03.2016 um 20:07 hat Max Reitz geschrieben:
>>>> As I responded to:
>>>> - http://lists.nongnu.org/archive/html/qemu-devel/2016-03/msg04464.html
>>>> - http://lists.nongnu.org/archive/html/qemu-devel/2016-03/msg05680.html
>>>>
>>>> I think a general solution for querying the block node tree would be
>>>> nice (I don't think we actually have one). The single patch in this
>>>> series implements such a command.
>>>>
>>>> However, this is an RFC because I'm not sure whether we really want this
>>>> and thus I didn't want to write the necessary tests for something we may
>>>> be going to discard anyway.
>>>
>>> I think we do want to have a way to query the tree structure in QMP. The
>>> part that I'm so sure about is whether we want a recursive command or
>>> one that just covers the children of a single node. If we want the
>>> latter, just adding a children field (which maps role names to node
>>> names) to query-block might be enough.
>>
>> Sounds fine in principle to me, but I'd like to add that I think we may
>> want to have a new command for querying a specific BDS. You don't get
>> much choice which nodes you query with query-block, and
>> query-named-block-nodes seems a bit bloated to me by now...
> 
> Maybe we need to start over with a new query-block-node command that
> takes a node name (or BB name as an alias for its root node) and returns
> information only about that node. That is, it adds node-name support
> compared to query-block, but it removes the recursive crap for backing
> files that we added there.

Yes, sounds good to me.

>> About the "mapping role names to node names" though; I suppose you mean
>> like { "file": "file-node", "backing": "other-qcow2-node" }. I'd have
>> loved to do that, but I couldn't imagine a way to represent that in the
>> QAPI schema.
> 
> Eric and Markus will tell us, but if nothing else helps:
> 
>     { 'children': 'any' }

But that's cheating! :-)

Max


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