[PATCH] md: allow a manual resync with md

You can trigger a 'check' with
  echo check > /sys/block/mdX/md/scan_mode
or a check-and-repair errors with
  echo repair > /sys/block/mdX/md/scan_mode

and read the current state from the same file.

Note: personalities need to know the different between 'check' and 'repair',
but don't yet.  Until they do, 'check' will be the same as 'repair' and will
just do a normal resync pass.

Signed-off-by: Neil Brown <neilb@suse.de>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/include/linux/raid/md_k.h b/include/linux/raid/md_k.h
index d1dad32..efd04dc 100644
--- a/include/linux/raid/md_k.h
+++ b/include/linux/raid/md_k.h
@@ -182,6 +182,8 @@
 	 * ERR:      and IO error was detected - abort the resync/recovery
 	 * INTR:     someone requested a (clean) early abort.
 	 * DONE:     thread is done and is waiting to be reaped
+	 * REQUEST:  user-space has requested a sync (used with SYNC)
+	 * CHECK:    user-space request for for check-only, no repair
 	 */
 #define	MD_RECOVERY_RUNNING	0
 #define	MD_RECOVERY_SYNC	1
@@ -189,6 +191,8 @@
 #define	MD_RECOVERY_INTR	3
 #define	MD_RECOVERY_DONE	4
 #define	MD_RECOVERY_NEEDED	5
+#define	MD_RECOVERY_REQUESTED	6
+#define	MD_RECOVERY_CHECK	7
 	unsigned long			recovery;
 
 	int				in_sync;	/* know to not need resync */