Bug#706415: grub-pc: grub-probe fails to find / on a ZFS-on-Linux system

[Steve McIntyre]

Hi Mike,

On Mon, Apr 29, 2013 at 02:59:43PM -0700, Mike Swanson wrote:
>Package: grub-pc
>Version: 1.99-27+deb7u1
>Severity: normal
>
>Dear Maintainer,
>
>I use zfsonlinux using the repository from http://zfsonlinux.org/debian.html
>and ZFS itself is contained in a LUKS volume, so it is a somewhat unusual
>setup.  There is an unencrypted /boot partition (ext4) that I use so that
>the kernel and initramfs can be loaded simply and I unlock the disk at
>the startup time.  Basically the layout of the disk is (gdisk -l):
>
>Number  Start (sector)    End (sector)  Size       Code  Name
>   1            2048       312371200   148.9 GiB   BF01  zfs
>   2       312371202       312581774   102.8 MiB   8300  boot
>   9              34            2047   1007.0 KiB  EF02  BIOS boot partition
>
>GRUB, in Debian at least, is not able to automatically create a configuration
>for my setup, mainly because there is no / device listed in /etc/fstab (ZFS
>on root, it manages the mountpoints itself).  This results in grub-probe
>erroring out, and it causes the package to be marked as being in an
>unconfigured state, resulting in this:
>
>root at philipjfry:~# dpkg --configure grub-pc
>Setting up grub-pc (1.99-27+deb7u1) ...
>grub-probe: error: cannot find a device for / (is /dev mounted?).
>Installation finished. No error reported.
>/usr/sbin/grub-probe: error: cannot find a device for / (is /dev mounted?).
>dpkg: error processing grub-pc (--configure):
> subprocess installed post-installation script returned error exit status 1
>Errors were encountered while processing:
> grub-pc
>
>GRUB still works fine writing the grub.cfg by hand (it's not that hard),
>and using grub-install afterwards.  It's still annoying to have this
>package remain in an "unconfigured" state!

Yes... :-/

Silly question - does this work OK in the previous version of grub-pc
(1.99-27)? I'm assuming not, but I'm interested in case there is a
regression here due to the changes I've made.

-- 
Steve McIntyre, Cambridge, UK.                                steve at einval.com
We don't need no education.
We don't need no thought control.