Re: [PATCH v8 4/7] qapi: add x-blockdev-replace command

[Vladimir Sementsov-Ogievskiy]

On 18.10.23 13:45, Markus Armbruster wrote:
> Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> writes:
>
> > Add a command that can replace bs in following BdrvChild structures:
> >
> >   - qdev blk root child
> >   - block-export blk root child
> >   - any child of BlockDriverState selected by child-name
> >
> > Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>

[..]

> > --- /dev/null
> > +++ b/stubs/blk-by-qdev-id.c
> > @@ -0,0 +1,9 @@
> > +#include "qemu/osdep.h"
> > +#include "qapi/error.h"
> > +#include "sysemu/block-backend.h"
> > +
> > +BlockBackend *blk_by_qdev_id(const char *id, Error **errp)
> > +{
> > +    error_setg(errp, "blk '%s' not found", id);
>
> Is this expected to happen?

Yes, if call the command from qemu-storage-daemon, where qdev-monitor is not 
linked in.

Maybe, better message would be

   "devices are not supported"

Maybe, that possible to use some 'if': notation in qapi, to not include support 
for qdev into the new command, when it compiled into qemu-storage-daemon? Seems 
that would not be simple, as we also need to split compilation of the command 
somehow, now it compiled once both for qemu and qemu tools..

> > +    return NULL;
> > +}
>
> [...]
>
> QAPI schema
> Acked-by: Markus Armbruster <armbru@redhat.com>

--
Best regards,
Vladimir