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

[Kevin Wolf]

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.

Kevin