1 files changed, 17 insertions, 0 deletions

diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index 90e951730a23..011827d0df25 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -3201,6 +3201,16 @@ static int run(struct mddev *mddev)
                         continue;
                 disk = conf->mirrors + disk_idx;
 
+                if (test_bit(Replacement, &rdev->flags)) {
+                        if (disk->replacement)
+                                goto out_free_conf;
+                        disk->replacement = rdev;
+                } else {
+                        if (disk->rdev)
+                                goto out_free_conf;
+                        disk->rdev = rdev;
+                }
+
                 disk->rdev = rdev;
                 disk_stack_limits(mddev->gendisk, rdev->bdev,
                                   rdev->data_offset << 9);
@@ -3228,6 +3238,13 @@ static int run(struct mddev *mddev)
 
                 disk = conf->mirrors + i;
 
+                if (!disk->rdev && disk->replacement) {
+                        /* The replacement is all we have - use it */
+                        disk->rdev = disk->replacement;
+                        disk->replacement = NULL;
+                        clear_bit(Replacement, &disk->rdev->flags);
+                }
+
                 if (!disk->rdev ||
                     !test_bit(In_sync, &disk->rdev->flags)) {
                         disk->head_position = 0;