svn commit: r208899 - stable/8/sys/geom/part

[Andrey V. Elsukov]

Author: ae
Date: Mon Jun  7 20:31:55 2010
New Revision: 208899
URL: http://svn.freebsd.org/changeset/base/208899

Log:
  MFC r197608:
  
  The first 96 bytes may not be zeroes. It can contain trivial boot
  code that merely emits an error and waits for a key press before
  rebooting. The error being that extended partitions are not
  bootable. The origin is presumed to be Windows 2000; Windows XP
  does not do this...
  
  For now, ignore the first 96 bytes when checking that the EBR is
  (for the most part) all zeroes.
  
  Tested by:	Mario Lobo <mlobo at digiart.art.br>
  		Dieter <dieterbsd at engineer.com>
  PR:		kern/141235
  Reviewed by:	marcel
  Approved by:	kib (mentor)
  Approved by:	re (bz)

Modified:
  stable/8/sys/geom/part/g_part_ebr.c
Directory Properties:
  stable/8/sys/   (props changed)
  stable/8/sys/amd64/include/xen/   (props changed)
  stable/8/sys/cddl/contrib/opensolaris/   (props changed)
  stable/8/sys/contrib/dev/acpica/   (props changed)
  stable/8/sys/contrib/pf/   (props changed)
  stable/8/sys/dev/xen/xenpci/   (props changed)
  stable/8/sys/geom/sched/   (props changed)

Modified: stable/8/sys/geom/part/g_part_ebr.c
==============================================================================
--- stable/8/sys/geom/part/g_part_ebr.c	Mon Jun  7 18:47:53 2010	(r208898)
+++ stable/8/sys/geom/part/g_part_ebr.c	Mon Jun  7 20:31:55 2010	(r208899)
@@ -410,13 +410,13 @@ g_part_ebr_probe(struct g_part_table *ta
 		goto out;
 
 	/*
-	 * The sector is all zeroes, except for the partition entries
-	 * and some signatures or disk serial number. Those can be
-	 * found in the 9 bytes immediately in front of the partition
-	 * table.
+	 * The sector is all zeroes, except for the partition entries,
+	 * pseudo boot code and some signatures or disk serial number.
+	 * The latter can be found in the 9 bytes immediately in front
+	 * of the partition table.
 	 */
 	sum = 0;
-	for (index = 0; index < DOSPARTOFF - 9; index++)
+	for (index = 96; index < DOSPARTOFF - 9; index++)
 		sum += buf[index];
 	if (sum != 0)
 		goto out;