Re: [Qemu-devel] [PATCH] block: Deprecate bdrv_set_read_only() and users

[Daniel P. Berrange]

On Wed, Nov 08, 2017 at 11:44:01AM +0100, Paolo Bonzini wrote:
> On 07/11/2017 18:39, Daniel P. Berrange wrote:
> > On Tue, Nov 07, 2017 at 06:26:38PM +0100, Kevin Wolf wrote:
> >> bdrv_set_read_only() is used by some block drivers to override the
> >> read-only option given by the user. This is not how read-only images
> >> generally work in QEMU: Instead of second guessing what the user really
> >> meant (which currently includes making an image read-only even if the
> >> user didn't only use the default, but explicitly said read-only=off), we
> >> should error out if we can't provide what the user requested.
> >>
> >> This adds deprecation warnings to all callers of bdrv_set_read_only() so
> >> that the behaviour can be corrected after the usual deprecation period.
> > 
> > All deprecations should be listed in "Deprecated features" appendix
> > in qemu-doc.texi. This probably fits in the 'system emulator command
> > line arguments' section, even though its talking about the need for
> > the user to add something extra, rather than deleting something they
> > currently use.
> 
> I am not sure this counts as deprecation, but it should go in the
> release notes as "future incompatible changes", and that section
> probably should go in qemu-doc.texi itself.

Yeah, adding a "Incompatible changes" appendix to the qemu-doc.texi
would be useful, listing the planned change, and when it is actually
made. That way apps adding support for a feature have an indication
of any incompatiblities they might need to care about.


Regards,
Daniel
-- 
|: https://berrange.com      -o-    https://www.flickr.com/photos/dberrange :|
|: https://libvirt.org         -o-            https://fstop138.berrange.com :|
|: https://entangle-photo.org    -o-    https://www.instagram.com/dberrange :|