Re: [PATCH 5/5] vvfat: add support for "size" options

["Clément Chigot" <chigot@adacore.com>]

On Wed, Nov 5, 2025 at 10:36 AM Kevin Wolf <kwolf@redhat.com> wrote:
>
> Am 05.11.2025 um 08:08 hat Markus Armbruster geschrieben:
> > Kevin Wolf <kwolf@redhat.com> writes:
> >
> > [...]
> >
> > > To me it looks a bit like what we really want is an enum for floppy
> > > sizes (though is there any real reason why we have only those two?), but
> > > an arbitrary size for hard disks.
> > >
> > > Without the enum, obviously, users could specify 1440k and that would do
> > > the right thing. Maybe special casing whatever 1.44M and 2.88M result
> > > in and translating them into 1440k and 2880k could be more justifiable
> > > than special casing 1M and 2M, but it would still be ugly.
> > >
> > > Markus, do you have any advice how this should be represented in QAPI?
> >
> > Still want answers here?
>
> Yes, I'm still not sure how we could best represent both hard disk and
> floppy sizes in vvfat in a way that isn't completely counterintuitive
> for users, that also isn't just arbitrary magic and that works on the
> command line.

For v2 (probably pushed sometimes this week), I've changed the
command-line approach to allow only `fat-size=1440K` and
`fat-size=2880K`. Other values will be rejected (including `1.44M` or
`2.88M`).
I'm not familiar with QAPI to see if that approach would fit properly.

> Unless the need for different sizes has gone away, but I don't think we
> found any other solution for the problem that would not require a
> configurable disk/file system size?
>
> Kevin
>