diff --git a/[refs] b/[refs]
index b8bde684b935..270d744ed1cb 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: b6a9ce688f613e2ee5f15e6720e0bb8520efc36e
+refs/heads/master: 848b3182365fdf5a05bcd5ed949071cac2c894b3
diff --git a/trunk/drivers/md/raid5.c b/trunk/drivers/md/raid5.c
index 4616bc3a6e71..3c3626d2a1f9 100644
--- a/trunk/drivers/md/raid5.c
+++ b/trunk/drivers/md/raid5.c
@@ -3811,13 +3811,13 @@ static sector_t reshape_request(mddev_t *mddev, sector_t sector_nr, int *skipped
 	safepos = conf->reshape_safe;
 	sector_div(safepos, data_disks);
 	if (mddev->delta_disks < 0) {
-		writepos -= reshape_sectors;
+		writepos -= min(reshape_sectors, writepos);
 		readpos += reshape_sectors;
 		safepos += reshape_sectors;
 	} else {
 		writepos += reshape_sectors;
-		readpos -= reshape_sectors;
-		safepos -= reshape_sectors;
+		readpos -= min(reshape_sectors, readpos);
+		safepos -= min(reshape_sectors, safepos);
 	}
 
 	/* 'writepos' is the most advanced device address we might write.