diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 147406d..e9dc780 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -1527,6 +1527,8 @@
 
 	/* device replace state */
 	struct btrfs_dev_replace dev_replace;
+
+	atomic_t mutually_exclusive_operation_running;
 };
 
 /*