Re: [Qemu-devel] [libvirt] [PATCH] qmp: Deprecate query-nodes option of query-blockstats

[Nir Soffer]

On Mon, Jan 28, 2019 at 6:13 PM Daniel P. Berrangé <address@hidden>
wrote:

> On Mon, Jan 28, 2019 at 04:37:50PM +0100, Kevin Wolf wrote:
> > Am 28.01.2019 um 16:15 hat Anton Kuchin geschrieben:
> > > This option is broken since a6baa60807 in v2.9 and returns mostly
> > > zeroes instead of real stats because actual querring of BlockStats
> > > that resides in blk is missing.
> > >
> > > And it makes no sense because with this option BlockDriverState-s
> > > are iterated but BlockAcctStats belong to BlockBackend and not BDS
> > > since 7f0e9da6f13 in v2.5
> > >
> > > Signed-off-by: Anton Kuchin <address@hidden>
> >
> > Isn't query-nodes the only way to get wr_highest_offset for the protocol
> > layer? oVirt depends on this, as far as I know.
>

We do, thanks for caring!

Libvirt just invokes 'query-blockstats' with no arguments, so is not
> relying on 'query-nodes' working. Given that libvirt doesn't use it,
> it doesn't seem like this is relevant for oVirt unless they were
> using QMP passthrough from libvirt.


We don't use QMP passthrough. We use only libvirt public APIs.

You can see what we use here:
https://github.com/oVirt/vdsm/blob/master/lib/vdsm/virt/drivemonitor.py

Nir



> That this has been broken
> since v2.9 though rather suggests oVirt doesn't use it.
>
> Regards,
> Daniel
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