diff --git a/fs/btrfs/reada.c b/fs/btrfs/reada.c
index 7e5d4ac800d9461cdd75baea54dd90c48d82a41e..f0cf5f3b865ae4d16c8f61b0662684b0838d53e6 100644
--- a/fs/btrfs/reada.c
+++ b/fs/btrfs/reada.c
@@ -708,7 +708,7 @@ static int reada_start_machine_dev(struct btrfs_fs_info *fs_info,
 	logical = re->logical;
 
 	spin_lock(&re->lock);
-	if (re->scheduled_for == NULL) {
+	if (!re->scheduled_for && !list_empty(&re->extctl)) {
 		re->scheduled_for = dev;
 		need_kick = 1;
 	}