[PATCH] md: support check-without-repair of raid10 arrays

Also keep count on the number of errors found.

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/drivers/md/raid10.c b/drivers/md/raid10.c
index 8f58a44..1fa70c3 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -1206,6 +1206,10 @@
 				break;
 		if (j == vcnt)
 			continue;
+		mddev->resync_mismatches += r10_bio->sectors;
+		if (test_bit(MD_RECOVERY_CHECK, &mddev->recovery))
+			/* Don't fix anything. */
+			continue;
 		/* Ok, we need to write this bio
 		 * First we need to fixup bv_offset, bv_len and
 		 * bi_vecs, as the read request might have corrupted these