bug#26339: [PATCH 02/18] system: Add extlinux support.

[Ludovic Courtès]

Hello,

Danny Milosavljevic <address@hidden> skribis:

> On Tue, 09 May 2017 22:40:23 +0200
> address@hidden (Ludovic Courtès) wrote:
>
>> > -> It was ok with one bootloader, it's more problematic with multiple  
>> > bootloaders. For example switching between two generations with two
>> > different bootloaders.  
>> 
>> OTOH, if it turns out to be safer to keep the current bootloader, which
>> is likely I think, then perhaps it’s best to not try to change.
>> 
>> I mean, I prefer a rollback that doesn’t roll back the bootloader over a
>> rollback that tries to do something smart and makes the system
>> unbootable.
>
> If there is a switch between extlinux and grub, the bootloader config file 
> format (and name, too) will change.
>
> So if you do switch the config file out but don't switch the actual 
> bootloader out it will not boot, right?

Unless you regenerate the bootloader’s config file upon
‘switch-configuration’.

> That means we have to take care that this doesn't happen.
>
> I still think an easy way would be to just always install the config files 
> for all the bootloaders that we support.  That way if there is a bootloader 
> that knows any of the configs, it will boot.  Can't think of a downside 
> either.

Yes, that’s also an option.  The downside would be that if we register
all of these as GC roots, then we end up retaining more than actually
needed.

Thanks,
Ludo’.