md: improve message about invalid superblock during autodetect

People try to use raid auto-detect with version-1 superblocks (which is not
supported) and get confused when they are told they have an invalid
superblock.

So be more explicit, and say it it is not a valid v0.90 superblock.
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/md/md.c

@@ -2074,8 +2074,10 @@ static mdk_rdev_t *md_import_device(dev_t newdev, int super_format, int super_mi
 			load_super(rdev, NULL, super_minor);
 		if (err == -EINVAL) {
 			printk(KERN_WARNING
-				"md: %s has invalid sb, not importing!\n",
-				bdevname(rdev->bdev,b));
+				"md: %s does not have a valid v%d.%d "
+			       "superblock, not importing!\n",
+				bdevname(rdev->bdev,b),
+			       super_format, super_minor);
 			goto abort_free;
 		}
 		if (err < 0) {
@@ -5771,7 +5773,7 @@ static void autostart_arrays(int part)
 	for (i = 0; i < dev_cnt; i++) {
 		dev_t dev = detected_devices[i];
 
-		rdev = md_import_device(dev,0, 0);
+		rdev = md_import_device(dev,0, 90);
 		if (IS_ERR(rdev))
 			continue;