Re: Bug#427289: more LVM stuff (Re: Bug#427289: grub-probe: error: unknown device when / is an encrypted LVM)

[Jeroen Dekkers]

At Mon, 4 Jun 2007 22:30:12 +0200,
Robert Millan wrote:
> 
> On Mon, Jun 04, 2007 at 10:11:30PM +0200, Jeroen Dekkers wrote:
> > At Sun, 3 Jun 2007 23:37:25 +0200,
> > Robert Millan wrote:
> > > Here's another report with issues about LVM.  I notice the device name is
> > > different than previous ones (note: device.map only has /dev/sda).
> > 
> > The problem seems to be that grub-install is probing for things
> > outside of /boot. GRUB shouldn't use anything outside of /boot to
> > start.
> 
> update-grub calls grub-probe a few times, in different places.  Some of them
> could be avoided, but at least these appear to be necessary:
> 
>   # Device containing our userland.  Typicaly used for root= parameter.
>   GRUB_DEVICE="`grub-probe --target=device /`"
> 
>   # Filesystem for the device containing our userland.  Used for stuff like
>   # choosing Hurd filesystem module.
>   GRUB_FS="`grub-probe --target=fs /`"
> 
> See also 00_header.in for code that might scan /usr/share/ in search of
> unifont.  If e.g. /usr is a separate partition, grub needs to know that
> somehow to load the font later.

GRUB shouldn't load anything from any other partition than /boot. The
whole reason that we have /boot partitions is that it might be
possible that the rest isn't readable by GRUB.

The reason we have grub-probe is to find out which modules need to be
in core.img. You're currently using grub-probe for other things and
that isn't always going to work. Grub-probe won't be able to parse
encrypted LVM volumes for example, and thus grub-probe --target=fs /
is never going to work if your / is encrypted.

Jeroen Dekkers