From: Michael Chang <mchang@suse.com>

The same as in the previous patch, add a support for installing grub
into an extended partition.

Here, we do not ignore extended partitions anymore. Instead we call a
hook that makes sure we have the partition when installing.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
References: https://bugzilla.novell.com/show_bug.cgi?id=750897

From: Andrey Borzenkov <arvidjaar@gmail.com>

Apply this logic only to primary extended partition. Ignore extended
partitions that are used to link together logical partitions.

References: https://bugzilla.novell.com/show_bug.cgi?id=785341
---
Index: grub-2.00/grub-core/partmap/msdos.c
===================================================================
--- grub-2.00.orig/grub-core/partmap/msdos.c
+++ grub-2.00/grub-core/partmap/msdos.c
@@ -188,13 +188,20 @@ grub_partition_msdos_iterate (grub_disk_
 			(unsigned long long) p.len);
 
 	  /* If this partition is a normal one, call the hook.  */
-	  if (! grub_msdos_partition_is_empty (e->type)
-	      && ! grub_msdos_partition_is_extended (e->type))
+	  if (! grub_msdos_partition_is_empty (e->type))
 	    {
-	      p.number++;
+	      if (!grub_msdos_partition_is_extended (e->type) || p.number < 3)
+		{
+		  p.number++;
 
-	      if (hook (disk, &p, hook_data))
-		return grub_errno;
+		  /* prevent someone doing mkfs or mkswap on an
+		  extended partition, but leave room for LILO */
+		  if (grub_msdos_partition_is_extended (e->type))
+		    p.len = 2;
+
+		  if (hook (disk, &p, hook_data))
+		    return grub_errno;
+		}
 	    }
 	  else if (p.number < 3)
 	    /* If this partition is a logical one, shouldn't increase the
