grub 1.99 configuration

grub 1.99 configuration

[Bruce Dubbs]

I'm trying to manually run grub-mkconfig to establish grub-1.99 
installation instructions for Linux From Scratch.

I am getting:

grub-mkconfig -o /boot/grub/grub.cfg
   /usr/sbin/grub-probe: error: cannot stat `/dev/root'

Doing some investigating grub-mkconfig is running:
   /usr/sbin/grub-probe --target=device /

Drilling down, grub-probe is doing:
   device_name = grub_guess_root_device (path);

Which in turn is doing:
   grub_find_root_device_from_mountinfo( "/", NULL );

This is reading /proc/self/mountinfo.  The problem here is that this 
file does not give the device, but specifies /dev/root:

13 1 8:15 / / rw,relatime - ext3 /dev/root 
rw,errors=continue,barrier=0,data=writeback

The kernel is 2.6.39.1, but 2.6.37 seems to give the same thing.
grub-probe should be able to detect /dev/sda15, but fails on newer kernels.

grub-probe for grub-1.98 works fine.  A grep there shows no use of
/proc/self/mountinfo.

Suggestions?

   -- Bruce

Re: grub 1.99 configuration

[Colin Watson]

On Sat, Jun 11, 2011 at 09:28:13PM -0500, Bruce Dubbs wrote:
> grub-mkconfig -o /boot/grub/grub.cfg
>   /usr/sbin/grub-probe: error: cannot stat `/dev/root'

  http://bugs.debian.org/627587

You can fix it by backporting r3318 from trunk:

  http://bazaar.launchpad.net/~vcs-imports/grub/grub2-bzr/revision/3318

The backport to 1.99 is not entirely straightforward.  Here's a version
that works with 1.99:

  http://anonscm.debian.org/loggerhead/pkg-grub/trunk/grub/revision/2435/debian/patches/lazy_stat.patch

-- 
Colin Watson                                       [cjwatson@ubuntu.com]

Re: grub 1.99 configuration

[Bruce Dubbs]

Colin Watson wrote:
> On Sat, Jun 11, 2011 at 09:28:13PM -0500, Bruce Dubbs wrote:
>> grub-mkconfig -o /boot/grub/grub.cfg
>>   /usr/sbin/grub-probe: error: cannot stat `/dev/root'
> 
>   http://bugs.debian.org/627587
> 
> You can fix it by backporting r3318 from trunk:
> 
>   http://bazaar.launchpad.net/~vcs-imports/grub/grub2-bzr/revision/3318
> 
> The backport to 1.99 is not entirely straightforward.  Here's a version
> that works with 1.99:
> 
>   http://anonscm.debian.org/loggerhead/pkg-grub/trunk/grub/revision/2435/debian/patches/lazy_stat.patch

Thanks for the info.  I'll check it out.

   -- Bruce

Re: grub 1.99 configuration

[Vladimir 'φ-coder/phcoder' Serbinenko]

[-- Attachment #1: Type: text/plain, Size: 1441 bytes --]

On 12.06.2011 04:28, Bruce Dubbs wrote:
> I'm trying to manually run grub-mkconfig to establish grub-1.99
> installation instructions for Linux From Scratch.
>
> I am getting:
>
> grub-mkconfig -o /boot/grub/grub.cfg
>   /usr/sbin/grub-probe: error: cannot stat `/dev/root'
>
> Doing some investigating grub-mkconfig is running:
>   /usr/sbin/grub-probe --target=device /
>
> Drilling down, grub-probe is doing:
>   device_name = grub_guess_root_device (path);
>
> Which in turn is doing:
>   grub_find_root_device_from_mountinfo( "/", NULL );
>
> This is reading /proc/self/mountinfo.  The problem here is that this
> file does not give the device, but specifies /dev/root:
>
> 13 1 8:15 / / rw,relatime - ext3 /dev/root
> rw,errors=continue,barrier=0,data=writeback
>
> The kernel is 2.6.39.1, but 2.6.37 seems to give the same thing.
> grub-probe should be able to detect /dev/sda15, but fails on newer
> kernels.
>
> grub-probe for grub-1.98 works fine.  A grep there shows no use of
> /proc/self/mountinfo.
>
> Suggestions?
>
update either udev or grub. normally /dev/root should be a symlink.
Newer grub-probe can cope with some other arrangements as well
>   -- Bruce
>
>
>
>
> _______________________________________________
> Grub-devel mailing list
> Grub-devel@gnu.org
> https://lists.gnu.org/mailman/listinfo/grub-devel
>


-- 
Regards
Vladimir 'φ-coder/phcoder' Serbinenko



[-- Attachment #2: OpenPGP digital signature --]
[-- Type: application/pgp-signature, Size: 294 bytes --]

Re: grub 1.99 configuration

[Bruce Dubbs]

Vladimir 'φ-coder/phcoder' Serbinenko wrote:
> On 12.06.2011 04:28, Bruce Dubbs wrote:
>> I'm trying to manually run grub-mkconfig to establish grub-1.99
>> installation instructions for Linux From Scratch.
>>
>> I am getting:
>>
>> grub-mkconfig -o /boot/grub/grub.cfg
>>   /usr/sbin/grub-probe: error: cannot stat `/dev/root'
>>
>> Doing some investigating grub-mkconfig is running:
>>   /usr/sbin/grub-probe --target=device /
>>
>> Drilling down, grub-probe is doing:
>>   device_name = grub_guess_root_device (path);
>>
>> Which in turn is doing:
>>   grub_find_root_device_from_mountinfo( "/", NULL );
>>
>> This is reading /proc/self/mountinfo.  The problem here is that this
>> file does not give the device, but specifies /dev/root:
>>
>> 13 1 8:15 / / rw,relatime - ext3 /dev/root
>> rw,errors=continue,barrier=0,data=writeback
>>
>> The kernel is 2.6.39.1, but 2.6.37 seems to give the same thing.
>> grub-probe should be able to detect /dev/sda15, but fails on newer
>> kernels.
>>
>> grub-probe for grub-1.98 works fine.  A grep there shows no use of
>> /proc/self/mountinfo.
>>
>> Suggestions?
>>
> update either udev or grub. normally /dev/root should be a symlink.
> Newer grub-probe can cope with some other arrangements as well

Well I'm using udev-171.  That is the most recent version.  We don't 
like to non-release package versions in LFS, but we do occasionally 
patch files.

I don't know when /dev/root became a 'device'.  Udev doesn't create it. 
  We also don't use an initrd.  That's not needed when you know in 
advance what your hardware configuration is.

I did work around the problem by manually creating the symlink.  I do 
not know of anything other than GRUB that needs it, but I don't use lvm.

In any case, I don't think GRUB should choke because /dev/root is missing.

   -- Bruce

Re: grub 1.99 configuration

[Vladimir 'φ-coder/phcoder' Serbinenko]

[-- Attachment #1: Type: text/plain, Size: 2347 bytes --]

On 24.06.2011 04:18, Bruce Dubbs wrote:
> Vladimir 'φ-coder/phcoder' Serbinenko wrote:
>> On 12.06.2011 04:28, Bruce Dubbs wrote:
>>> I'm trying to manually run grub-mkconfig to establish grub-1.99
>>> installation instructions for Linux From Scratch.
>>>
>>> I am getting:
>>>
>>> grub-mkconfig -o /boot/grub/grub.cfg
>>>   /usr/sbin/grub-probe: error: cannot stat `/dev/root'
>>>
>>> Doing some investigating grub-mkconfig is running:
>>>   /usr/sbin/grub-probe --target=device /
>>>
>>> Drilling down, grub-probe is doing:
>>>   device_name = grub_guess_root_device (path);
>>>
>>> Which in turn is doing:
>>>   grub_find_root_device_from_mountinfo( "/", NULL );
>>>
>>> This is reading /proc/self/mountinfo.  The problem here is that this
>>> file does not give the device, but specifies /dev/root:
>>>
>>> 13 1 8:15 / / rw,relatime - ext3 /dev/root
>>> rw,errors=continue,barrier=0,data=writeback
>>>
>>> The kernel is 2.6.39.1, but 2.6.37 seems to give the same thing.
>>> grub-probe should be able to detect /dev/sda15, but fails on newer
>>> kernels.
>>>
>>> grub-probe for grub-1.98 works fine.  A grep there shows no use of
>>> /proc/self/mountinfo.
>>>
>>> Suggestions?
>>>
>> update either udev or grub. normally /dev/root should be a symlink.
>> Newer grub-probe can cope with some other arrangements as well
>
> Well I'm using udev-171.  That is the most recent version.  We don't
> like to non-release package versions in LFS, but we do occasionally
> patch files.
>
> I don't know when /dev/root became a 'device'.  Udev doesn't create
> it.  We also don't use an initrd.  That's not needed when you know in
> advance what your hardware configuration is.
>
> I did work around the problem by manually creating the symlink.  I do
> not know of anything other than GRUB that needs it, but I don't use lvm.
>
> In any case, I don't think GRUB should choke because /dev/root is
> missing.
>
it's fixed now but handling these cases requires to scan /dev to find
the matching device based on major/minor pair which is slower, sometimes
much slower.
>   -- Bruce
>
> _______________________________________________
> Grub-devel mailing list
> Grub-devel@gnu.org
> https://lists.gnu.org/mailman/listinfo/grub-devel


-- 
Regards
Vladimir 'φ-coder/phcoder' Serbinenko



[-- Attachment #2: OpenPGP digital signature --]
[-- Type: application/pgp-signature, Size: 294 bytes --]