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

* Issue in grub-probe when boot device is located on device mapper partition.
@ 2013-07-16 12:56 Eldar Yusupov
  2013-07-16 17:51 ` Vladimir 'φ-coder/phcoder' Serbinenko
  0 siblings, 1 reply; 2+ messages in thread
From: Eldar Yusupov @ 2013-07-16 12:56 UTC (permalink / raw)
  To: grub-devel

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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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