bug#62140: enable LVM in Grub

[Emmanuel Beffara <manu@beffara.org>]

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.

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 ?

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.

-- 
Emmanuel