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:
>> 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
> 
> Uhm.. I can't understand why it can't realpath() on that file.  It does
> certainly exist, doesn't it?  Otherwise grub-probe wouldn't have found it
> in first place.

It did exists. But it does not anymore.
I do not know why and when devfs style paths stopped being created.

The udev still provide a 'devfs.rules' but it does not seem to be used anymore.
The the README.Debian of udev, we can find "The rules file devfs.rules [...]
is provided to support devfs-style names, but it's deprecated and its use
is highly discouraged."

I really think that grub stored this path in /boot/grub/devices.map
when it was used in the system and fails now that the path is not used any more.
I do not remember doing something myself about managing or not devfs
paths (ie I think I always use the defaults from the udev package).

Not also that the installer was using devfs a long time (so these paths can
come from the grub run from the installer). According to the udev changelog,
it does not anymore:
"  * Switched d-i from devfs-like to regular names. (Closes: #431556)"

> Please verify it exists.  Also, try "grub-probe -t device /".

It does not exists any more on my system and since I removed the device.map file,
all works well (it had been recreated without these devfs paths)

> And make sure you were using the latest grub-common, it has improvements on
> this area.

You are right:

vdanjean at cayuga:/tmp$ sudo vi /boot/grub/device.map
vdanjean at cayuga:/tmp$ cat /boot/grub/device.map
(hd0) /dev/scsi/host0/bus0/target0/lun0/disc
#(hd0)	/dev/sda
vdanjean at cayuga:/tmp$ sudo grub-probe  /
grub-probe: error: unknown device
vdanjean at cayuga:/tmp$ sudo grub-probe -t device /
/dev/mapper/cayuga-root
vdanjean at cayuga:/tmp$ sudo vi /boot/grub/device.map
vdanjean at cayuga:/tmp$ cat /boot/grub/device.map
(hd0)	/dev/sda
vdanjean at cayuga:/tmp$ sudo grub-probe  /
ext2
vdanjean at cayuga:/tmp$ sudo grub-probe -t device /
/dev/mapper/cayuga-root
vdanjean at cayuga:/tmp$ dpkg -l grub
[...]
ii  grub                     0.97-36                  GRand Unified Bootloader (Legacy version)

  Best regards,
    Vincent

-- 
Vincent Danjean                 Adresse: Laboratoire d'Informatique de Grenoble
Téléphone:  +33 4 76 61 20 11            ENSIMAG - antenne de Montbonnot
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Email: Vincent.Danjean at imag.fr           38330 Montbonnot Saint Martin