[PATCH] md: make md on-disk bitmaps not host-endian

Current bitmaps use set_bit et.al and so are host-endian, which means
not-portable.  Oops.

Define a new version number (4) for which bitmaps are little-endian.

Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/include/linux/raid/md.h b/include/linux/raid/md.h
index ffa316c..91467a3 100644
--- a/include/linux/raid/md.h
+++ b/include/linux/raid/md.h
@@ -66,8 +66,10 @@
  *     and major_version/minor_version accordingly
  * >=2 means that Internal bitmaps are supported by setting MD_SB_BITMAP_PRESENT
  *     in the super status byte
+ * >=3 means that bitmap superblock version 4 is supported, which uses
+ *     little-ending representation rather than host-endian
  */
-#define MD_PATCHLEVEL_VERSION           2
+#define MD_PATCHLEVEL_VERSION           3
 
 extern int register_md_personality (int p_num, mdk_personality_t *p);
 extern int unregister_md_personality (int p_num);