diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index 78da339..d9ee4ed 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -66,7 +66,8 @@
  */
 static int max_queued_requests = 1024;
 
-static void allow_barrier(struct r1conf *conf);
+static void allow_barrier(struct r1conf *conf, sector_t start_next_window,
+			  sector_t bi_sector);
 static void lower_barrier(struct r1conf *conf);
 
 static void * r1bio_pool_alloc(gfp_t gfp_flags, void *data)
@@ -227,6 +228,8 @@
 	struct bio *bio = r1_bio->master_bio;
 	int done;
 	struct r1conf *conf = r1_bio->mddev->private;
+	sector_t start_next_window = r1_bio->start_next_window;
+	sector_t bi_sector = bio->bi_sector;
 
 	if (bio->bi_phys_segments) {
 		unsigned long flags;
@@ -234,6 +237,11 @@
 		bio->bi_phys_segments--;
 		done = (bio->bi_phys_segments == 0);
 		spin_unlock_irqrestore(&conf->device_lock, flags);
+		/*
+		 * make_request() might be waiting for
+		 * bi_phys_segments to decrease
+		 */
+		wake_up(&conf->wait_barrier);
 	} else
 		done = 1;
 
@@ -245,7 +253,7 @@
 		 * Wake up any possible resync thread that waits for the device
 		 * to go idle.
 		 */
-		allow_barrier(conf);
+		allow_barrier(conf, start_next_window, bi_sector);
 	}
 }
 
@@ -827,10 +835,19 @@
 	/* block any new IO from starting */
 	conf->barrier++;
 
-	/* Now wait for all pending IO to complete */
+	/* For these conditions we must wait:
+	 * A: while the array is in frozen state
+	 * B: while barrier >= RESYNC_DEPTH, meaning resync reach
+	 *    the max count which allowed.
+	 * C: next_resync + RESYNC_SECTORS > start_next_window, meaning
+	 *    next resync will reach to the window which normal bios are
+	 *    handling.
+	 */
 	wait_event_lock_irq(conf->wait_barrier,
 			    !conf->array_frozen &&
-			    !conf->nr_pending && conf->barrier < RESYNC_DEPTH,
+			    conf->barrier < RESYNC_DEPTH &&
+			    (conf->start_next_window >=
+			     conf->next_resync + RESYNC_SECTORS),
 			    conf->resync_lock);
 
 	spin_unlock_irq(&conf->resync_lock);
@@ -846,10 +863,33 @@
 	wake_up(&conf->wait_barrier);
 }
 
-static void wait_barrier(struct r1conf *conf)
+static bool need_to_wait_for_sync(struct r1conf *conf, struct bio *bio)
 {
+	bool wait = false;
+
+	if (conf->array_frozen || !bio)
+		wait = true;
+	else if (conf->barrier && bio_data_dir(bio) == WRITE) {
+		if (conf->next_resync < RESYNC_WINDOW_SECTORS)
+			wait = true;
+		else if ((conf->next_resync - RESYNC_WINDOW_SECTORS
+				>= bio_end_sector(bio)) ||
+			 (conf->next_resync + NEXT_NORMALIO_DISTANCE
+				<= bio->bi_sector))
+			wait = false;
+		else
+			wait = true;
+	}
+
+	return wait;
+}
+
+static sector_t wait_barrier(struct r1conf *conf, struct bio *bio)
+{
+	sector_t sector = 0;
+
 	spin_lock_irq(&conf->resync_lock);
-	if (conf->barrier) {
+	if (need_to_wait_for_sync(conf, bio)) {
 		conf->nr_waiting++;
 		/* Wait for the barrier to drop.
 		 * However if there are already pending
@@ -863,21 +903,65 @@
 		wait_event_lock_irq(conf->wait_barrier,
 				    !conf->array_frozen &&
 				    (!conf->barrier ||
-				    (conf->nr_pending &&
+				    ((conf->start_next_window <
+				      conf->next_resync + RESYNC_SECTORS) &&
 				     current->bio_list &&
 				     !bio_list_empty(current->bio_list))),
 				    conf->resync_lock);
 		conf->nr_waiting--;
 	}
+
+	if (bio && bio_data_dir(bio) == WRITE) {
+		if (conf->next_resync + NEXT_NORMALIO_DISTANCE
+		    <= bio->bi_sector) {
+			if (conf->start_next_window == MaxSector)
+				conf->start_next_window =
+					conf->next_resync +
+					NEXT_NORMALIO_DISTANCE;
+
+			if ((conf->start_next_window + NEXT_NORMALIO_DISTANCE)
+			    <= bio->bi_sector)
+				conf->next_window_requests++;
+			else
+				conf->current_window_requests++;
+		}
+		if (bio->bi_sector >= conf->start_next_window)
+			sector = conf->start_next_window;
+	}
+
 	conf->nr_pending++;
 	spin_unlock_irq(&conf->resync_lock);
+	return sector;
 }
 
-static void allow_barrier(struct r1conf *conf)
+static void allow_barrier(struct r1conf *conf, sector_t start_next_window,
+			  sector_t bi_sector)
 {
 	unsigned long flags;
+
 	spin_lock_irqsave(&conf->resync_lock, flags);
 	conf->nr_pending--;
+	if (start_next_window) {
+		if (start_next_window == conf->start_next_window) {
+			if (conf->start_next_window + NEXT_NORMALIO_DISTANCE
+			    <= bi_sector)
+				conf->next_window_requests--;
+			else
+				conf->current_window_requests--;
+		} else
+			conf->current_window_requests--;
+
+		if (!conf->current_window_requests) {
+			if (conf->next_window_requests) {
+				conf->current_window_requests =
+					conf->next_window_requests;
+				conf->next_window_requests = 0;
+				conf->start_next_window +=
+					NEXT_NORMALIO_DISTANCE;
+			} else
+				conf->start_next_window = MaxSector;
+		}
+	}
 	spin_unlock_irqrestore(&conf->resync_lock, flags);
 	wake_up(&conf->wait_barrier);
 }
@@ -1012,6 +1096,7 @@
 	int first_clone;
 	int sectors_handled;
 	int max_sectors;
+	sector_t start_next_window;
 
 	/*
 	 * Register the new request and wait if the reconstruction
@@ -1041,7 +1126,7 @@
 		finish_wait(&conf->wait_barrier, &w);
 	}
 
-	wait_barrier(conf);
+	start_next_window = wait_barrier(conf, bio);
 
 	bitmap = mddev->bitmap;
 
@@ -1162,6 +1247,7 @@
 
 	disks = conf->raid_disks * 2;
  retry_write:
+	r1_bio->start_next_window = start_next_window;
 	blocked_rdev = NULL;
 	rcu_read_lock();
 	max_sectors = r1_bio->sectors;
@@ -1230,14 +1316,24 @@
 	if (unlikely(blocked_rdev)) {
 		/* Wait for this device to become unblocked */
 		int j;
+		sector_t old = start_next_window;
 
 		for (j = 0; j < i; j++)
 			if (r1_bio->bios[j])
 				rdev_dec_pending(conf->mirrors[j].rdev, mddev);
 		r1_bio->state = 0;
-		allow_barrier(conf);
+		allow_barrier(conf, start_next_window, bio->bi_sector);
 		md_wait_for_blocked_rdev(blocked_rdev, mddev);
-		wait_barrier(conf);
+		start_next_window = wait_barrier(conf, bio);
+		/*
+		 * We must make sure the multi r1bios of bio have
+		 * the same value of bi_phys_segments
+		 */
+		if (bio->bi_phys_segments && old &&
+		    old != start_next_window)
+			/* Wait for the former r1bio(s) to complete */
+			wait_event(conf->wait_barrier,
+				   bio->bi_phys_segments == 1);
 		goto retry_write;
 	}
 
@@ -1437,11 +1533,14 @@
 
 static void close_sync(struct r1conf *conf)
 {
-	wait_barrier(conf);
-	allow_barrier(conf);
+	wait_barrier(conf, NULL);
+	allow_barrier(conf, 0, 0);
 
 	mempool_destroy(conf->r1buf_pool);
 	conf->r1buf_pool = NULL;
+
+	conf->next_resync = 0;
+	conf->start_next_window = MaxSector;
 }
 
 static int raid1_spare_active(struct mddev *mddev)
@@ -2713,6 +2812,9 @@
 	conf->pending_count = 0;
 	conf->recovery_disabled = mddev->recovery_disabled - 1;
 
+	conf->start_next_window = MaxSector;
+	conf->current_window_requests = conf->next_window_requests = 0;
+
 	err = -EIO;
 	for (i = 0; i < conf->raid_disks * 2; i++) {
 
diff --git a/drivers/md/raid1.h b/drivers/md/raid1.h
index 331a98a..9bebca7 100644
--- a/drivers/md/raid1.h
+++ b/drivers/md/raid1.h
@@ -41,6 +41,19 @@
 	 */
 	sector_t		next_resync;
 
+	/* When raid1 starts resync, we divide array into four partitions
+	 * |---------|--------------|---------------------|-------------|
+	 *        next_resync   start_next_window       end_window
+	 * start_next_window = next_resync + NEXT_NORMALIO_DISTANCE
+	 * end_window = start_next_window + NEXT_NORMALIO_DISTANCE
+	 * current_window_requests means the count of normalIO between
+	 *   start_next_window and end_window.
+	 * next_window_requests means the count of normalIO after end_window.
+	 * */
+	sector_t		start_next_window;
+	int			current_window_requests;
+	int			next_window_requests;
+
 	spinlock_t		device_lock;
 
 	/* list of 'struct r1bio' that need to be processed by raid1d,
@@ -112,6 +125,7 @@
 						 * in this BehindIO request
 						 */
 	sector_t		sector;
+	sector_t		start_next_window;
 	int			sectors;
 	unsigned long		state;
 	struct mddev		*mddev;