diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index 4d40d9d..3214606 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -764,7 +764,7 @@
 	mirror_info_t *mirror;
 	r1bio_t *r1_bio;
 	struct bio *read_bio;
-	int i, targets = 0, disks;
+	int i, disks;
 	struct bitmap *bitmap;
 	unsigned long flags;
 	const int rw = bio_data_dir(bio);
@@ -772,6 +772,9 @@
 	const unsigned long do_flush_fua = (bio->bi_rw & (REQ_FLUSH | REQ_FUA));
 	mdk_rdev_t *blocked_rdev;
 	int plugged;
+	int first_clone;
+	int sectors_handled;
+	int max_sectors;
 
 	/*
 	 * Register the new request and wait if the reconstruction
@@ -832,7 +835,6 @@
 		/*
 		 * read balancing logic:
 		 */
-		int max_sectors;
 		int rdisk;
 
 read_again:
@@ -872,7 +874,6 @@
 			/* could not read all from this device, so we will
 			 * need another r1_bio.
 			 */
-			int sectors_handled;
 
 			sectors_handled = (r1_bio->sector + max_sectors
 					   - bio->bi_sector);
@@ -906,9 +907,15 @@
 	/*
 	 * WRITE:
 	 */
-	/* first select target devices under spinlock and
+	/* first select target devices under rcu_lock and
 	 * inc refcount on their rdev.  Record them by setting
 	 * bios[x] to bio
+	 * If there are known/acknowledged bad blocks on any device on
+	 * which we have seen a write error, we want to avoid writing those
+	 * blocks.
+	 * This potentially requires several writes to write around
+	 * the bad blocks.  Each set of writes gets it's own r1bio
+	 * with a set of bios attached.
 	 */
 	plugged = mddev_check_plugged(mddev);
 
@@ -916,6 +923,7 @@
  retry_write:
 	blocked_rdev = NULL;
 	rcu_read_lock();
+	max_sectors = r1_bio->sectors;
 	for (i = 0;  i < disks; i++) {
 		mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
 		if (rdev && unlikely(test_bit(Blocked, &rdev->flags))) {
@@ -923,17 +931,56 @@
 			blocked_rdev = rdev;
 			break;
 		}
-		if (rdev && !test_bit(Faulty, &rdev->flags)) {
-			atomic_inc(&rdev->nr_pending);
-			if (test_bit(Faulty, &rdev->flags)) {
-				rdev_dec_pending(rdev, mddev);
-				r1_bio->bios[i] = NULL;
-			} else {
-				r1_bio->bios[i] = bio;
-				targets++;
+		r1_bio->bios[i] = NULL;
+		if (!rdev || test_bit(Faulty, &rdev->flags)) {
+			set_bit(R1BIO_Degraded, &r1_bio->state);
+			continue;
+		}
+
+		atomic_inc(&rdev->nr_pending);
+		if (test_bit(WriteErrorSeen, &rdev->flags)) {
+			sector_t first_bad;
+			int bad_sectors;
+			int is_bad;
+
+			is_bad = is_badblock(rdev, r1_bio->sector,
+					     max_sectors,
+					     &first_bad, &bad_sectors);
+			if (is_bad < 0) {
+				/* mustn't write here until the bad block is
+				 * acknowledged*/
+				set_bit(BlockedBadBlocks, &rdev->flags);
+				blocked_rdev = rdev;
+				break;
 			}
-		} else
-			r1_bio->bios[i] = NULL;
+			if (is_bad && first_bad <= r1_bio->sector) {
+				/* Cannot write here at all */
+				bad_sectors -= (r1_bio->sector - first_bad);
+				if (bad_sectors < max_sectors)
+					/* mustn't write more than bad_sectors
+					 * to other devices yet
+					 */
+					max_sectors = bad_sectors;
+				rdev_dec_pending(rdev, mddev);
+				/* We don't set R1BIO_Degraded as that
+				 * only applies if the disk is
+				 * missing, so it might be re-added,
+				 * and we want to know to recover this
+				 * chunk.
+				 * In this case the device is here,
+				 * and the fact that this chunk is not
+				 * in-sync is recorded in the bad
+				 * block log
+				 */
+				continue;
+			}
+			if (is_bad) {
+				int good_sectors = first_bad - r1_bio->sector;
+				if (good_sectors < max_sectors)
+					max_sectors = good_sectors;
+			}
+		}
+		r1_bio->bios[i] = bio;
 	}
 	rcu_read_unlock();
 
@@ -944,48 +991,56 @@
 		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);
 		md_wait_for_blocked_rdev(blocked_rdev, mddev);
 		wait_barrier(conf);
 		goto retry_write;
 	}
 
-	if (targets < conf->raid_disks) {
-		/* array is degraded, we will not clear the bitmap
-		 * on I/O completion (see raid1_end_write_request) */
-		set_bit(R1BIO_Degraded, &r1_bio->state);
+	if (max_sectors < r1_bio->sectors) {
+		/* We are splitting this write into multiple parts, so
+		 * we need to prepare for allocating another r1_bio.
+		 */
+		r1_bio->sectors = max_sectors;
+		spin_lock_irq(&conf->device_lock);
+		if (bio->bi_phys_segments == 0)
+			bio->bi_phys_segments = 2;
+		else
+			bio->bi_phys_segments++;
+		spin_unlock_irq(&conf->device_lock);
 	}
-
-	/* do behind I/O ?
-	 * Not if there are too many, or cannot allocate memory,
-	 * or a reader on WriteMostly is waiting for behind writes 
-	 * to flush */
-	if (bitmap &&
-	    (atomic_read(&bitmap->behind_writes)
-	     < mddev->bitmap_info.max_write_behind) &&
-	    !waitqueue_active(&bitmap->behind_wait))
-		alloc_behind_pages(bio, r1_bio);
+	sectors_handled = r1_bio->sector + max_sectors - bio->bi_sector;
 
 	atomic_set(&r1_bio->remaining, 1);
 	atomic_set(&r1_bio->behind_remaining, 0);
 
-	bitmap_startwrite(bitmap, bio->bi_sector, r1_bio->sectors,
-				test_bit(R1BIO_BehindIO, &r1_bio->state));
+	first_clone = 1;
 	for (i = 0; i < disks; i++) {
 		struct bio *mbio;
 		if (!r1_bio->bios[i])
 			continue;
 
 		mbio = bio_clone_mddev(bio, GFP_NOIO, mddev);
-		r1_bio->bios[i] = mbio;
+		md_trim_bio(mbio, r1_bio->sector - bio->bi_sector, max_sectors);
 
-		mbio->bi_sector	= r1_bio->sector + conf->mirrors[i].rdev->data_offset;
-		mbio->bi_bdev = conf->mirrors[i].rdev->bdev;
-		mbio->bi_end_io	= raid1_end_write_request;
-		mbio->bi_rw = WRITE | do_flush_fua | do_sync;
-		mbio->bi_private = r1_bio;
+		if (first_clone) {
+			/* do behind I/O ?
+			 * Not if there are too many, or cannot
+			 * allocate memory, or a reader on WriteMostly
+			 * is waiting for behind writes to flush */
+			if (bitmap &&
+			    (atomic_read(&bitmap->behind_writes)
+			     < mddev->bitmap_info.max_write_behind) &&
+			    !waitqueue_active(&bitmap->behind_wait))
+				alloc_behind_pages(mbio, r1_bio);
 
+			bitmap_startwrite(bitmap, r1_bio->sector,
+					  r1_bio->sectors,
+					  test_bit(R1BIO_BehindIO,
+						   &r1_bio->state));
+			first_clone = 0;
+		}
 		if (r1_bio->behind_pages) {
 			struct bio_vec *bvec;
 			int j;
@@ -1003,6 +1058,15 @@
 				atomic_inc(&r1_bio->behind_remaining);
 		}
 
+		r1_bio->bios[i] = mbio;
+
+		mbio->bi_sector	= (r1_bio->sector +
+				   conf->mirrors[i].rdev->data_offset);
+		mbio->bi_bdev = conf->mirrors[i].rdev->bdev;
+		mbio->bi_end_io	= raid1_end_write_request;
+		mbio->bi_rw = WRITE | do_flush_fua | do_sync;
+		mbio->bi_private = r1_bio;
+
 		atomic_inc(&r1_bio->remaining);
 		spin_lock_irqsave(&conf->device_lock, flags);
 		bio_list_add(&conf->pending_bio_list, mbio);
@@ -1013,6 +1077,19 @@
 	/* In case raid1d snuck in to freeze_array */
 	wake_up(&conf->wait_barrier);
 
+	if (sectors_handled < (bio->bi_size >> 9)) {
+		/* We need another r1_bio.  It has already been counted
+		 * in bio->bi_phys_segments
+		 */
+		r1_bio = mempool_alloc(conf->r1bio_pool, GFP_NOIO);
+		r1_bio->master_bio = bio;
+		r1_bio->sectors = (bio->bi_size >> 9) - sectors_handled;
+		r1_bio->state = 0;
+		r1_bio->mddev = mddev;
+		r1_bio->sector = bio->bi_sector + sectors_handled;
+		goto retry_write;
+	}
+
 	if (do_sync || !bitmap || !plugged)
 		md_wakeup_thread(mddev->thread);