[PATCH] sanity checks for RAID

[Robert Millan <rmh@aybabtu.com>]

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A pair of sanity checks for RAID.  Jeroen, I'd appreciate if you could have a
quick look.

The second case I haven't run into, but the first I have (in a single-disk
RAID0 I setup for testing).

I wonder if I'm fixing the symptoms of a bug rather than the bug, but I
really don't see what could be wrong in our superblock read routine, plus
even if there's a bug somewhere else this check makes sense to me as a general
safeguard.

-- 
Robert Millan

<GPLv2> I know my rights; I want my phone call!
<DRM> What use is a phone call… if you are unable to speak?
(as seen on /.)

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diff -x configure -x config.h.in -x CVS -x '*~' -x '*.mk' -urp ../grub2/disk/raid.c ./disk/raid.c
--- ../grub2/disk/raid.c	2007-12-30 09:52:03.000000000 +0100
+++ ./disk/raid.c	2008-02-06 23:22:46.000000000 +0100
@@ -493,6 +493,28 @@ grub_raid_scan_device (const char *name)
   /* Add the device to the array. */
   array->device[sb.this_disk.number].name = grub_strdup (name);
   array->device[sb.this_disk.number].disk = grub_disk_open (name);
+
+  if (array->disk_size != array->device[sb.this_disk.number]->total_sectors)
+    {
+      if (array->total_devs == 1)
+	{
+	  grub_dprintf ("raid", "Array contains only one disk, but its size (0x%llx) "
+			"doesn't match with size indicated by superblock (0x%llx).  "
+			"Assuming superblock is wrong.\n",
+			array->device[sb.this_disk.number]->total_sectors, array->disk_size);
+	  array->disk_size = array->device[sb.this_disk.number]->total_sectors;
+	}
+      else if (array->level == 1)
+	{
+	  grub_dprintf ("raid", "Array is RAID level 1, but the size of disk %d (0x%llx) "
+			"doesn't match with size indicated by superblock (0x%llx).  "
+			"Assuming superblock is wrong.\n",
+			sb.this_disk.number,
+			array->device[sb.this_disk.number]->total_sectors, array->disk_size);
+	  array->disk_size = array->device[sb.this_disk.number]->total_sectors;
+	}
+    }
+
   
   if (! array->device[sb.this_disk.number].name
       || ! array->device[sb.this_disk.number].disk)