Re: [Qemu-block] [PATCH V2 2/8] qapi: add compress parameters to Qcow2 Blockdev options

[Daniel P. Berrange]

On Thu, Jul 13, 2017 at 10:52:41AM +0200, Kevin Wolf wrote:
> Am 13.07.2017 um 10:45 hat Peter Lieven geschrieben:
> > Am 10.07.2017 um 15:30 schrieb Kevin Wolf:
> > >Am 10.07.2017 um 15:24 hat Peter Lieven geschrieben:
> > >>Am 10.07.2017 um 15:10 schrieb Kevin Wolf:
> > >>>Am 29.06.2017 um 12:57 hat Peter Lieven geschrieben:
> > >>>>Signed-off-by: Peter Lieven <address@hidden>
> > >>>>---
> > >>>>  qapi/block-core.json | 44 +++++++++++++++++++++++++++++++++++++++++++-
> > >>>>  1 file changed, 43 insertions(+), 1 deletion(-)
> > >>>How does this make sense as a runtime option? What would happen if the
> > >>>image contains one compression format and I specify another one on the
> > >>>command line or in blockdev-add?
> > >>>
> > >>>Shouldn't it just be a create-time option and when you run qemu, it uses
> > >>>whatever format that image has?
> > >>I was asked to add it here. It is indeed only a create option and has
> > >>no other effect.
> > >But if it's only a create option, why is it added to blockdev-add?
> > 
> > Is there already a separate schemata for the create options?
> 
> If you mean a separate schema file, no. Putting it in the same file
> isn't a problem either, but hooking it up in structs used by
> blockdev-add (or other QMP commands) probably is.
> 
> So if you want to follow Dan's suggestion, I think you just need to put
> the new type into the schema, without referencing it anywhere except in
> qcow2's .bdrv_create C implementation.

Yep, that's exactly what I intended by my suggestion

Regards,
Daniel
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