Index: linux-2.6.22.14/drivers/md/raid5.c
===================================================================
--- linux-2.6.22.14.orig/drivers/md/raid5.c
+++ linux-2.6.22.14/drivers/md/raid5.c
@@ -1268,6 +1268,8 @@ static int add_stripe_bio(struct stripe_
 		bi->bi_next = *bip;
 	*bip = bi;
 	bi->bi_phys_segments ++;
+	if (bio_sync(bi) && !forwrite)
+		clear_bit(R5_UPTODATE, &sh->dev[dd_idx].flags); /* force to read from disk. */
 	spin_unlock_irq(&conf->device_lock);
 	spin_unlock(&sh->lock);
 
@@ -2972,6 +2974,8 @@ static int make_request(request_queue_t 
 			      test_bit(BIO_UPTODATE, &bi->bi_flags)
 			        ? 0 : -EIO);
 	}
+	if (bio_sync(bi))
+		raid5_unplug_device(q);
 	return 0;
 }