Re: Issue in grub-probe when boot device is located on device mapper partition.

["Vladimir 'φ-coder/phcoder' Serbinenko" <phcoder@gmail.com>]

Please always try latest version (bzr trunk) before reporting any bug. 
This particular one was fixed quite some time ago.
On 16.07.2013 14:56, Eldar Yusupov wrote:
> Hi,
>
> I've hit an issue when trying to reinstall grub on my system.
> My /boot partition is located on /dev/mapper/pdc_djabadcbjep1 device.
> However, when grub-install executes grub-probe -t fs /boot, and the
> latter one starts probing the filesystem, it incorrectly tries to open
> hostdisk//dev/mapper/pdc_djabadcbje device instead
> of hostdisk//dev/mapper/pdc_djabadcbje,msdos1.
>
> Here's verbose output of grub-probe:
> # grub2-probe -v -t fs /boot/
> grub2-probe: info: cannot open `/boot/grub2/device.map': No such file or
> directory.
> grub2-probe: info: Looking for /dev/mapper/pdc_djabadcbjep1.
> grub2-probe: info: /dev/mapper/pdc_djabadcbje is a parent of
> /dev/mapper/pdc_djabadcbjep1.
> grub2-probe: info: Looking for /dev/mapper/pdc_djabadcbjep1.
> grub2-probe: info: /dev/mapper/pdc_djabadcbje is a parent of
> /dev/mapper/pdc_djabadcbjep1.
> grub2-probe: info: Looking for /dev/mapper/pdc_djabadcbjep1.
> grub2-probe: info: /dev/mapper/pdc_djabadcbje is a parent of
> /dev/mapper/pdc_djabadcbjep1.
> grub2-probe: info: opening hostdisk//dev/mapper/pdc_djabadcbje.
> grub2-probe: info: the size of hostdisk//dev/mapper/pdc_djabadcbje is
> 1953124992.
> grub2-probe: error: unknown filesystem.
>
> I think that the issue is in util/get_root.c
> in convert_system_partition_to_system_disk() function - it does not seem
> to determine if the device is partition or not for device-mapper case.
>
> The following change seems to fix the issue, however I'm not really
> familiar with device mapper and can't be sure if it's correct:
>
> 	  /* Counter-intuitively, device-mapper refers to the disk-like
> 	     device containing a DM-RAID partition device as a "child" of
> 	     the partition device.  */
> 	  child = dm_tree_next_child (&handle, node, 0);
> 	  if (! child)
> 	    {
> 	      grub_util_info ("%s has no DM children", path);
> 	      goto devmapper_out;
> 	    }
> 	  child_uuid = dm_tree_node_get_uuid (child);
> 	  if (! child_uuid)
> 	    {
> 	      grub_util_info ("%s child has no DM uuid", path);
> 	      goto devmapper_out;
> 	    }
> 	  else if (strncmp (child_uuid, "DMRAID-", 7) != 0)
> 	    {
> 	      grub_util_info ("%s child is not DM-RAID", path);
> 	      goto devmapper_out;
> 	    }
> 	  child_name = dm_tree_node_get_name (child);
> 	  if (! child_name)
> 	    {
> 	      grub_util_info ("%s child has no DM name", path);
> 	      goto devmapper_out;
> 	    }
>
> mapper_name = child_name;
> + *is_part = 1;
>
> --
> --
> Regards,
> Eldar Yusupov.
>
>
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