Bug#707831: UUID detection code broken, wrongly uses UUID

[C. Dominik Bódi]

This bug affects wheezy as well. I just had trouble booting a wheezy
system after adding a second Physical Volume to my LVM setup.

The workaround is setting
GRUB_DISABLE_LINUX_UUID=true
in /etc/default/grub

That will make boot again as it will use the
root=/dev/mapper/nameofrootlv
for the kernel cmdline in /boot/grub/grub.cfg

I'm still getting those errors when doing an update-grub:
"physical volume pv0 not found" (many of them)

Not using the workaround in advance will kill remote servers, if you
don't have access to a KVM console, spice or anything to fix the kernel
cmdline in grub's boot menu manually, though.

The machine affected is a KVM/quemu VM instance. That machine is using
virtio disks, thus I'm having /dev/vda, /dev/vdb and so on.

I've noticed that udev does not generate devices nodes for virtio disks
in /dev/disk/by-id nor /dev/disk/by-uuid . Perhaps this is why grub is
having trouble finding those disks.

Additionally, this might be a corner case when one is using a complete
unpartitioned disk as LVM Physical Volume, as the second PV I've added
to the system is an unpartitioned virtio disk.

Strangely enough, on another KVM/qemu VM running unstable (acutally
running on the same host as the wheezy VM), but having a similar virtio
disk setup, everything is fine. I'm seeing the virtio disk nodes in
/dev/disk/by-id and grub is not complaining about not having found PVs,
either.

I'd likt to ask to re-open this bug, as this still affects wheezy. I'd
kindly request a fix backported to wheezy, as well. Thank you.

Regards,
Dominik Bódi

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