Re: Future of installing GRUB to LVM volumes (and loop devices)

[Sebastian Pipping <sebastian@pipping.org>]

Hello Andrei,


On 05/15/2015 11:34 AM, Andrei Borzenkov wrote:
> On Fri, May 15, 2015 at 12:28 PM, Sebastian Pipping
> <sebastian@pipping.org> wrote:
>>
>> I understand that some relations may be hard to impossible to detect.
>> The cases that I have are plain parent-child relations, though.
>> It would rock the house to get these cases covered again.
>>
>> (On a side note, text "unknown device type loop0" looks like a bug to me
>> since "loop0" is not a type.)
> 
> It comes from Open Firmware part. May be it should be downgraded to
> Info. But as long as it happens in grub-probe only it is OK.

my point was more about the text of the error message.


>>>>> Half working solution would be to assume that it is always child map.
>>>>>
>>>>> Or you can take shortcut and assume that /dev/mapper/XXXXpY is
>>>>> partition of /dev/mapper/XXX but you still will need to verify it.
>>>>>
>>>>> Patches are welcome.
>>>>
>>>> I am still wondering: how come it was working in GRUB 2.00 but now
>>>> longer is?
>>>>
>>>
>>> But by you said in previous message that HEAD works? Not sure how
>>> though :)
>>
>> That referred to the '(hd0)'-parameter-with-device-map case, only.
>>
>> This patch to grml-debootstrap says best what has stopped working:
>> https://github.com/hartwork/grml-debootstrap/commit/a705ff45c2d053b0d90ec51700e2d25a760106f3
>>
> 
> Could you please describe your exact configuration that does not work
> (including all devices and their relationships) and what does not
> work? Sorry if you did it already but I somehow lost track here.

Sure.

The setup is a single plain partition in an LVM volume.

The following commands reproduce the setup (in RAM if /tmp is tmpfs).
With a plain LVM volume, the error is the same tough.

  # tmpfile="$(mktemp)"
  # echo "${tmpfile}"
  # truncate --size=$((100*1024**2)) "${tmpfile}"
  # loop_device_2="$(losetup --show -f "${tmpfile}")"
  # echo "${loop_device_2}"
  # vgcreate vg "${loop_device_2}"
  # lvcreate --name lv -l 100%free vg
  # sleep 1

  # parted /dev/vg/lv --script mklabel msdos
  # parted /dev/vg/lv --script mkpart primary ext4 4m 100%
  # sleep 1
  # mkfs.ext4 /dev/mapper/vg-lv1
  # mkdir /mnt/lv-root
  # mount /dev/mapper/vg-lv1 /mnt/lv-root
  # mkdir /mnt/lv-root/boot
  # grub-install --boot-directory=/mnt/lv-root/boot /dev/mapper/vg-lv ;
echo $?
  Installing for i386-pc platform.
  grub-install: error: disk
`lvmid/KO9MVd-KNgN-Nbo0-RJb0-pGdK-K7lO-apdskW/rrvxSA-SFY6-P6gy-1jYv-0ims-RmyL-m1KZMB'
not found.
  1

Best,



Sebastian