diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index b16d2ee..b45d641 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -318,25 +318,34 @@
 	rdev_dec_pending(conf->mirrors[mirror].rdev, conf->mddev);
 }
 
+static void close_write(r1bio_t *r1_bio)
+{
+	/* it really is the end of this request */
+	if (test_bit(R1BIO_BehindIO, &r1_bio->state)) {
+		/* free extra copy of the data pages */
+		int i = r1_bio->behind_page_count;
+		while (i--)
+			safe_put_page(r1_bio->behind_bvecs[i].bv_page);
+		kfree(r1_bio->behind_bvecs);
+		r1_bio->behind_bvecs = NULL;
+	}
+	/* clear the bitmap if all writes complete successfully */
+	bitmap_endwrite(r1_bio->mddev->bitmap, r1_bio->sector,
+			r1_bio->sectors,
+			!test_bit(R1BIO_Degraded, &r1_bio->state),
+			test_bit(R1BIO_BehindIO, &r1_bio->state));
+	md_write_end(r1_bio->mddev);
+}
+
 static void r1_bio_write_done(r1bio_t *r1_bio)
 {
-	if (atomic_dec_and_test(&r1_bio->remaining))
-	{
-		/* it really is the end of this request */
-		if (test_bit(R1BIO_BehindIO, &r1_bio->state)) {
-			/* free extra copy of the data pages */
-			int i = r1_bio->behind_page_count;
-			while (i--)
-				safe_put_page(r1_bio->behind_bvecs[i].bv_page);
-			kfree(r1_bio->behind_bvecs);
-			r1_bio->behind_bvecs = NULL;
-		}
-		/* clear the bitmap if all writes complete successfully */
-		bitmap_endwrite(r1_bio->mddev->bitmap, r1_bio->sector,
-				r1_bio->sectors,
-				!test_bit(R1BIO_Degraded, &r1_bio->state),
-				test_bit(R1BIO_BehindIO, &r1_bio->state));
-		md_write_end(r1_bio->mddev);
+	if (!atomic_dec_and_test(&r1_bio->remaining))
+		return;
+
+	if (test_bit(R1BIO_WriteError, &r1_bio->state))
+		reschedule_retry(r1_bio);
+	else {
+		close_write(r1_bio);
 		if (test_bit(R1BIO_MadeGood, &r1_bio->state))
 			reschedule_retry(r1_bio);
 		else
@@ -360,12 +369,10 @@
 	/*
 	 * 'one mirror IO has finished' event handler:
 	 */
-	r1_bio->bios[mirror] = NULL;
-	to_put = bio;
 	if (!uptodate) {
-		md_error(r1_bio->mddev, conf->mirrors[mirror].rdev);
-		/* an I/O failed, we can't clear the bitmap */
-		set_bit(R1BIO_Degraded, &r1_bio->state);
+		set_bit(WriteErrorSeen,
+			&conf->mirrors[mirror].rdev->flags);
+		set_bit(R1BIO_WriteError, &r1_bio->state);
 	} else {
 		/*
 		 * Set R1BIO_Uptodate in our master bio, so that we
@@ -380,6 +387,8 @@
 		sector_t first_bad;
 		int bad_sectors;
 
+		r1_bio->bios[mirror] = NULL;
+		to_put = bio;
 		set_bit(R1BIO_Uptodate, &r1_bio->state);
 
 		/* Maybe we can clear some bad blocks. */
@@ -1724,6 +1733,101 @@
 	}
 }
 
+static void bi_complete(struct bio *bio, int error)
+{
+	complete((struct completion *)bio->bi_private);
+}
+
+static int submit_bio_wait(int rw, struct bio *bio)
+{
+	struct completion event;
+	rw |= REQ_SYNC;
+
+	init_completion(&event);
+	bio->bi_private = &event;
+	bio->bi_end_io = bi_complete;
+	submit_bio(rw, bio);
+	wait_for_completion(&event);
+
+	return test_bit(BIO_UPTODATE, &bio->bi_flags);
+}
+
+static int narrow_write_error(r1bio_t *r1_bio, int i)
+{
+	mddev_t *mddev = r1_bio->mddev;
+	conf_t *conf = mddev->private;
+	mdk_rdev_t *rdev = conf->mirrors[i].rdev;
+	int vcnt, idx;
+	struct bio_vec *vec;
+
+	/* bio has the data to be written to device 'i' where
+	 * we just recently had a write error.
+	 * We repeatedly clone the bio and trim down to one block,
+	 * then try the write.  Where the write fails we record
+	 * a bad block.
+	 * It is conceivable that the bio doesn't exactly align with
+	 * blocks.  We must handle this somehow.
+	 *
+	 * We currently own a reference on the rdev.
+	 */
+
+	int block_sectors;
+	sector_t sector;
+	int sectors;
+	int sect_to_write = r1_bio->sectors;
+	int ok = 1;
+
+	if (rdev->badblocks.shift < 0)
+		return 0;
+
+	block_sectors = 1 << rdev->badblocks.shift;
+	sector = r1_bio->sector;
+	sectors = ((sector + block_sectors)
+		   & ~(sector_t)(block_sectors - 1))
+		- sector;
+
+	if (test_bit(R1BIO_BehindIO, &r1_bio->state)) {
+		vcnt = r1_bio->behind_page_count;
+		vec = r1_bio->behind_bvecs;
+		idx = 0;
+		while (vec[idx].bv_page == NULL)
+			idx++;
+	} else {
+		vcnt = r1_bio->master_bio->bi_vcnt;
+		vec = r1_bio->master_bio->bi_io_vec;
+		idx = r1_bio->master_bio->bi_idx;
+	}
+	while (sect_to_write) {
+		struct bio *wbio;
+		if (sectors > sect_to_write)
+			sectors = sect_to_write;
+		/* Write at 'sector' for 'sectors'*/
+
+		wbio = bio_alloc_mddev(GFP_NOIO, vcnt, mddev);
+		memcpy(wbio->bi_io_vec, vec, vcnt * sizeof(struct bio_vec));
+		wbio->bi_sector = r1_bio->sector;
+		wbio->bi_rw = WRITE;
+		wbio->bi_vcnt = vcnt;
+		wbio->bi_size = r1_bio->sectors << 9;
+		wbio->bi_idx = idx;
+
+		md_trim_bio(wbio, sector - r1_bio->sector, sectors);
+		wbio->bi_sector += rdev->data_offset;
+		wbio->bi_bdev = rdev->bdev;
+		if (submit_bio_wait(WRITE, wbio) == 0)
+			/* failure! */
+			ok = rdev_set_badblocks(rdev, sector,
+						sectors, 0)
+				&& ok;
+
+		bio_put(wbio);
+		sect_to_write -= sectors;
+		sector += sectors;
+		sectors = block_sectors;
+	}
+	return ok;
+}
+
 static void raid1d(mddev_t *mddev)
 {
 	r1bio_t *r1_bio;
@@ -1775,7 +1879,8 @@
 				md_done_sync(mddev, s, 1);
 			} else
 				sync_request_write(mddev, r1_bio);
-		} else if (test_bit(R1BIO_MadeGood, &r1_bio->state)) {
+		} else if (test_bit(R1BIO_MadeGood, &r1_bio->state) ||
+			   test_bit(R1BIO_WriteError, &r1_bio->state)) {
 			int m;
 			for (m = 0; m < conf->raid_disks ; m++)
 				if (r1_bio->bios[m] == IO_MADE_GOOD) {
@@ -1785,7 +1890,24 @@
 						r1_bio->sector,
 						r1_bio->sectors);
 					rdev_dec_pending(rdev, mddev);
+				} else if (r1_bio->bios[m] != NULL) {
+					/* This drive got a write error.  We
+					 * need to narrow down and record
+					 * precise write errors.
+					 */
+					if (!narrow_write_error(r1_bio, m)) {
+						md_error(mddev,
+							 conf->mirrors[m].rdev);
+						/* an I/O failed, we can't clear
+						 * the bitmap */
+						set_bit(R1BIO_Degraded,
+							&r1_bio->state);
+					}
+					rdev_dec_pending(conf->mirrors[m].rdev,
+							 mddev);
 				}
+			if (test_bit(R1BIO_WriteError, &r1_bio->state))
+				close_write(r1_bio);
 			raid_end_bio_io(r1_bio);
 		} else if (test_bit(R1BIO_ReadError, &r1_bio->state)) {
 			int disk;