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

[Fam Zheng]

On Mon, 11/03 15:32, Kevin Wolf wrote:
> 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 <address@hidden>
> > > 
> > > > 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()).

Yes, to be consistent with drive-backup.

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

I am not sure, it's still blockdev-backup, not blocknode-backup.

I think that may be another thing, to changed drive-*'s @device parameter, and
blockdev-*'s @device and @target to accept node names, altogether.

Fam