Index: linux-2.6.16.60-0.33/drivers/md/raid5.c
===================================================================
--- linux-2.6.16.60-0.33.orig/drivers/md/raid5.c
+++ linux-2.6.16.60-0.33/drivers/md/raid5.c
@@ -900,6 +900,8 @@ 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);
 
@@ -1617,6 +1619,8 @@ static int make_request (request_queue_t
 		bi->bi_end_io(bi, bytes, 0);
 	}
 	spin_unlock_irq(&conf->device_lock);
+	if (bio_sync(bi))
+		raid5_unplug_device(q);
 	return 0;
 }