On 07/19/2017 03:44 AM, Kevin Wolf wrote: > Commits 0db832f and 6cdbceb introduced the automatic insertion of filter > nodes above the top layer of mirror and commit block jobs. The > assumption made there was that since libvirt doesn't do node-level > management of the block layer yet, it shouldn't be affected by added > nodes.
Those both landed in 2.9. So this is a regression we're trying to fix. > > This is true as far as commands issued by libvirt are concerned. It only > uses BlockBackend names to address nodes, so any operations it performs > still operate on the root of the tree as intended. > > However, the assumption breaks down when you consider query commands, > which return data for the wrong node now. These commands also return > information on some child nodes (bs->file and/or bs->backing), which > libvirt does make use of, and which refer to the wrong nodes, too. > > One of the consequences is that oVirt gets wrong information about the > image size and stops the VM in response as long as a mirror or commit > job is running: > > https://bugzilla.redhat.com/show_bug.cgi?id=1470634 > > This patch fixes the problem by hiding the implict nodes created > automatically by the mirror and commit block jobs in the output of > query-block and BlockBackend-based query-blockstats as long as the user > doesn't indicate that they are aware of those nodes by providing a node > name for them in the QMP command to start the block job. The approach makes sense to me. I see from the rest of this thread that you'll need a v2 to get the implementation of the approach correct, but I think you're on the right track. > > The node-based commands query-named-block-nodes and query-blockstats > with query-nodes=true still show all nodes, including implicit ones. > This ensures that users that are capable of node-level management can > still access the full information; users that only know BlockBackends > won't use these commands. > > Cc: qemu-sta...@nongnu.org > Signed-off-by: Kevin Wolf <kw...@redhat.com> > --- -- Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3266 Virtualization: qemu.org | libvirt.org
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