diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 76eed592371e..73cdf43a6479 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -318,6 +318,7 @@ static void init_stripe(struct stripe_head *sh, sector_t sector, int previous)
 
 	remove_hash(sh);
 
+	sh->generation = conf->generation - previous;
 	sh->disks = previous ? conf->previous_raid_disks : conf->raid_disks;
 	sh->sector = sector;
 	stripe_set_idx(sector, conf, previous, sh);
@@ -341,7 +342,8 @@ static void init_stripe(struct stripe_head *sh, sector_t sector, int previous)
 	insert_hash(conf, sh);
 }
 
-static struct stripe_head *__find_stripe(raid5_conf_t *conf, sector_t sector, int disks)
+static struct stripe_head *__find_stripe(raid5_conf_t *conf, sector_t sector,
+					 short generation)
 {
 	struct stripe_head *sh;
 	struct hlist_node *hn;
@@ -349,7 +351,7 @@ static struct stripe_head *__find_stripe(raid5_conf_t *conf, sector_t sector, in
 	CHECK_DEVLOCK();
 	pr_debug("__find_stripe, sector %llu\n", (unsigned long long)sector);
 	hlist_for_each_entry(sh, hn, stripe_hash(conf, sector), hash)
-		if (sh->sector == sector && sh->disks == disks)
+		if (sh->sector == sector && sh->generation == generation)
 			return sh;
 	pr_debug("__stripe %llu not in cache\n", (unsigned long long)sector);
 	return NULL;
@@ -363,7 +365,6 @@ get_active_stripe(raid5_conf_t *conf, sector_t sector,
 		  int previous, int noblock)
 {
 	struct stripe_head *sh;
-	int disks = previous ? conf->previous_raid_disks : conf->raid_disks;
 
 	pr_debug("get_stripe, sector %llu\n", (unsigned long long)sector);
 
@@ -373,7 +374,7 @@ get_active_stripe(raid5_conf_t *conf, sector_t sector,
 		wait_event_lock_irq(conf->wait_for_stripe,
 				    conf->quiesce == 0,
 				    conf->device_lock, /* nothing */);
-		sh = __find_stripe(conf, sector, disks);
+		sh = __find_stripe(conf, sector, conf->generation - previous);
 		if (!sh) {
 			if (!conf->inactive_blocked)
 				sh = get_free_stripe(conf);
@@ -3648,7 +3649,7 @@ static int make_request(struct request_queue *q, struct bio * bi)
 				if ((mddev->delta_disks < 0
 				     ? logical_sector >= conf->reshape_progress
 				     : logical_sector < conf->reshape_progress)
-				    && disks == conf->previous_raid_disks)
+				    && previous)
 					/* mismatch, need to try again */
 					must_retry = 1;
 				spin_unlock_irq(&conf->device_lock);
@@ -4837,6 +4838,7 @@ static int raid5_start_reshape(mddev_t *mddev)
 	else
 		conf->reshape_progress = 0;
 	conf->reshape_safe = conf->reshape_progress;
+	conf->generation++;
 	spin_unlock_irq(&conf->device_lock);
 
 	/* Add some new drives, as many as will fit.
diff --git a/drivers/md/raid5.h b/drivers/md/raid5.h
index b2edcc434e41..a081fb40a5a2 100644
--- a/drivers/md/raid5.h
+++ b/drivers/md/raid5.h
@@ -198,6 +198,8 @@ struct stripe_head {
 	struct hlist_node	hash;
 	struct list_head	lru;	      /* inactive_list or handle_list */
 	struct raid5_private_data *raid_conf;
+	short			generation;	/* increments with every
+						 * reshape */
 	sector_t		sector;		/* sector of this row */
 	short			pd_idx;		/* parity disk index */
 	short			qd_idx;		/* 'Q' disk index for raid6 */
@@ -348,6 +350,7 @@ struct raid5_private_data {
 	 */
 	sector_t		reshape_safe;
 	int			previous_raid_disks;
+	short			generation; /* increments with every reshape */
 
 	struct list_head	handle_list; /* stripes needing handling */
 	struct list_head	hold_list; /* preread ready stripes */