diff --git a/include/linux/drbd.h b/include/linux/drbd.h
index 8723f2a..15a1472 100644
--- a/include/linux/drbd.h
+++ b/include/linux/drbd.h
@@ -357,6 +357,13 @@
 
 #define UUID_JUST_CREATED ((__u64)4)
 
+enum write_ordering_e {
+	WO_NONE,
+	WO_DRAIN_IO,
+	WO_BDEV_FLUSH,
+	WO_BIO_BARRIER
+};
+
 /* magic numbers used in meta data and network packets */
 #define DRBD_MAGIC 0x83740267
 #define DRBD_MAGIC_BIG 0x835a