md: Add '4' to the list of levels for which bitmaps are supported

I really should make this a function of the personality....
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Adrian Bunk <bunk@kernel.org>

drivers/md/md.c

@@ -761,7 +761,8 @@ static int super_90_validate(mddev_t *mddev, mdk_rdev_t *rdev)
 
 		if (sb->state & (1<<MD_SB_BITMAP_PRESENT) &&
 		    mddev->bitmap_file == NULL) {
-			if (mddev->level != 1 && mddev->level != 5 && mddev->level != 6
+			if (mddev->level != 1 && mddev->level != 4
+			    && mddev->level != 5 && mddev->level != 6
 			    && mddev->level != 10) {
 				/* FIXME use a better test */
 				printk(KERN_WARNING "md: bitmaps not supported for this level.\n");
@@ -1093,6 +1094,7 @@ static int super_1_validate(mddev_t *mddev, mdk_rdev_t *rdev)
 		if ((le32_to_cpu(sb->feature_map) & MD_FEATURE_BITMAP_OFFSET) &&
 		    mddev->bitmap_file == NULL ) {
 			if (mddev->level != 1 && mddev->level != 5 && mddev->level != 6
+			    && mddev->level != 4
 			    && mddev->level != 10) {
 				printk(KERN_WARNING "md: bitmaps not supported for this level.\n");
 				return -EINVAL;