diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 5a80098..5f49215 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -1814,6 +1814,8 @@
 	struct list_head delalloc_inodes;
 	struct list_head delalloc_root;
 	u64 nr_delalloc_inodes;
+
+	struct mutex ordered_extent_mutex;
 	/*
 	 * this is used by the balancing code to wait for all the pending
 	 * ordered extents