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

[Kevin Wolf <kwolf@redhat.com>]

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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.

> 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' }

Kevin

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