Bug#473532: grub-probe: error: Cannot get the real path of `/dev/scsi/...'

[Vincent Danjean]

Robert Millan wrote:
> On Mon, Mar 31, 2008 at 09:45:36AM +0200, Vincent Danjean wrote:
>> Package: grub
>> Version: 0.97-35
>> Severity: important
>>
>>   Hi,
>>
>> With the new package grub 0.97-35, when update-grub is launched
>> (manually or by installing a new kernel package), I got:
>>
>> Running postinst hook script /usr/sbin/update-grub.
>> Searching for GRUB installation directory ... found: /boot/grub
>> grub-probe: error: Cannot get the real path of
>> `/dev/scsi/host0/bus0/target0/lun0/disc'
>> User postinst hook script [/usr/sbin/update-grub] exited with value 1
>>
>> If I run manually 'grub-probe /', I also got this error.
>>
>> In fstab, I have:
>> /dev/mapper/cayuga-root /       ext3    defaults,errors=remount-ro 0 1
>>
>>
>> In /boot/grub/device.map, I had
>> (hd0) /dev/scsi/host0/bus0/target0/lun0/disc
> 
> Where is your root filesystem?  Is it a physical device (like /dev/scsi/...) or
> an LVM/whatever abstraction?

The root FS is on a LVM partition:
vdanjean at cayuga:~$ mount | grep "/ "
/dev/mapper/cayuga-root on / type ext3 (rw,errors=remount-ro)
vdanjean at cayuga:~$ ls -l /dev/mapper/cayuga-root
brw-rw---- 1 root disk 254, 0 avr  1 13:48 /dev/mapper/cayuga-root
vdanjean at cayuga:~$

> Is your /boot a separate partition?  Where is it?  What does 'grub-probe /boot'
> do?

Yes, it is a 'classical' partition:
vdanjean at cayuga:~$ mount | grep "/boot"
/dev/sda5 on /boot type ext3 (rw)
vdanjean at cayuga:~$ sudo grub-probe /boot
ext2
vdanjean at cayuga:~$

In /etc/fstab, I have:
/dev/mapper/cayuga-root /	ext3    defaults,errors=remount-ro 0       1
LABEL=cayuga:BOOTFS	/boot		ext3    defaults        0       2

Note: now that I did what I described in hte bug report, grub-probe on / works:
vdanjean at cayuga:~$ sudo grub-probe /
ext2
vdanjean at cayuga:~$


My idea about this bug is that, for a reason or another, grub records old-devfs style
path in /boot/grub/devices and does not update this file
I did not use devfs since a very long time
I did not change manually udev rules recently (but I do not know if udev were creating
devfs path until recently. Now, it does not)

  I hope these info can help you

  Best regards,
    Vincent