bug#62140: enable LVM in Grub

[Maxim Cournoyer <maxim.cournoyer@gmail.com>]

Hi,

Emmanuel Beffara <manu@beffara.org> writes:

> Hi,
>
> De Maxim Cournoyer le 24/03/2023 à 13:24:
>> OK, thanks for explaining.  Could you please try
>> https://issues.guix.gnu.org/60442 (by applying the patch to a local guix
>> checkout, building it, then 'sudo -E ./pre-inst-env sudo guix system
>> reconfigure /path/to/your/config.scm)?  The test suite was broken it
>> seems (it passed without the fix), but perhaps the fix still does work?
>
> I did as you suggested, and unfortunately the patch has no observable effect
> on my system.

Thanks for testing it!

> I can't say it comes as a surprise. Indeed, what the patch does is set the
> environment variable `GRUB_PRELOAD_MODULES` before calling `grub-install`,
> which is expected to have no effect: this variable is used by `grub-mkconfig`
> to generate a `grub.cfg`, but the code in Guix assembles a Grub configuration
> file itself and never calls `grub-mkconfig`. The same applies to the variable
> `GRUB_ENABLE_CRYPTODISK`, by the way. Maybe the way `grub.cfg` is produced has
> changed at some point in history ?

I'm not sure, but I agree it's confusing to have extraneous setenv
there if they serve no purpose (and my understanding is the same as
yours: I don't see how that'd work).

> The only hypothesis I can make is that it would influence `grub-install` by
> preloading the given modules in the installed image, but that is not the case.
> According to Grub's documentation, passing `--modules=...` to `grub-install`
> would have this effect, but I'm not sure it is the right approach.

Since we already generate a custom grub.cfg, the right approach is
probably to add any needed directive directly to it.

-- 
Thanks,
Maxim