Re: [Qemu-devel] [PATCH 1/3] qmp: Add command 'blockdev-backup'

[Kevin Wolf <kwolf@redhat.com>]

Am 03.11.2014 um 02:46 hat Fam Zheng geschrieben:
> On Fri, 10/31 10:01, Kevin Wolf wrote:
> > Am 11.09.2014 um 07:05 hat Fam Zheng geschrieben:
> > > Similar to drive-backup, but this command uses a device id as target
> > > instead of creating/opening an image file.
> > > 
> > > Also add blocker on target bs, since the target is also a named device
> > > now.
> > > 
> > > Add check and report error for bs == target which became possible but is
> > > an illegal case with introduction of blockdev-backup.
> > > 
> > > Signed-off-by: Fam Zheng <famz@redhat.com>
> > 
> > > diff --git a/qapi/block-core.json b/qapi/block-core.json
> > > index a685d02..b953c7b 100644
> > > --- a/qapi/block-core.json
> > > +++ b/qapi/block-core.json
> > > @@ -669,6 +669,40 @@
> > >              '*on-target-error': 'BlockdevOnError' } }
> > >  
> > >  ##
> > > +# @BlockdevBackup
> > > +#
> > > +# @device: the name of the device which should be copied.
> > > +#
> > > +# @target: the name of the backup target device.
> > 
> > Both of these are either a BlockBackend ID or a BDS node-name, right? Do
> > we have a standard way of expressing this? "name of the device" isn't
> > quite clear.
> 
> "name of the device" is used everywhere to document the "device" parameters in
> our json schema. Since we have BlockBackend now, device-name and node-name
> could be better distinguished. All we have to do is giving a beautiful name to
> both.
> 
> [This patch is only a copy&paste and is consistent with the rest part of the
> file. So I'll leave it for now :]

The rest of the file doesn't accept node names. But looking at your
actual code, it seems that you are doing the same (by usign bdrv_find()
instead of bdrv_lookup_bs()).

Shouldn't a proper blockdev-* command accept node names as well?

Kevin