--- linux/fanotify.h
+++ linux/fanotify.h
@@ -81,6 +81,11 @@
 
 #define FANOTIFY_METADATA_VERSION	3
 
+/* this is a special 64bit data type that is 8-byte aligned */
+#if !defined(__aligned_u64)
+#define __aligned_u64 __u64 __attribute__((aligned(8)))
+#endif
+
 struct fanotify_event_metadata {
 	__u32 event_len;
 	__u8 vers;