Re: [RFC PATCH v2 3/4] block: Support multiple reopening with x-blockdev-reopen

[Alberto Garcia <berto@igalia.com>]

On Wed 24 Feb 2021 01:33:05 PM CET, Kevin Wolf <kwolf@redhat.com> wrote:
>> >   { 'command': 'x-blockdev-reopen',
>> > -  'data': 'BlockdevOptions', 'boxed': true }
>> > +  'data': { 'options': ['BlockdevOptions'] } }
>> 
>> Do we also want to drop x- prefix?
>
> libvirt really wants to have a stable blockdev-reopen interface in 6.0
> because enabling the incremental backup code depends on this (they
> just toggle the readonly flag if I understand correctly, so most of
> the work we're currently doing isn't even relevant at this moment for
> libvirt).
>
> Given that the soft freeze is coming closer (March 16), I wonder if we
> should just make this API change and declare the interface stable. We
> can then make Vladimir's fixes and the file reopening on top of it -
> if it's in time for 6.0, that would be good, but if not we could move
> it to 6.1 without impacting libvirt.

I expect to publish the new version of my patches next week, although
they still apply on top of Vladimir's code, which is not rebased.

We can of course simply update the API and implement the functionality
later, but apart from dropping the prefix we would also be changing the
parameters so qmp_x_blockdev_reopen() would also need to be modified.

Berto