Btrfs: properly set blocksize when adding new device.

---

Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 37a8ea2..1546fa6 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -1079,6 +1079,8 @@
 	if (ret)
 		goto out_close_bdev;
 
+	set_blocksize(device->bdev, 4096);
+
 	total_bytes = btrfs_super_total_bytes(&root->fs_info->super_copy);
 	btrfs_set_super_total_bytes(&root->fs_info->super_copy,
 				    total_bytes + device->total_bytes);