fanotify: resize pid and reorder structure

resize pid and reorder the fanotify_event_metadata so it is naturally
aligned and we can work towards dropping the packed attributed
Signed-off-by: NTvrtko Ursulin <tvrtko.ursulin@sophos.com>
Cc: Andreas Dilger <adilger@dilger.ca>
Signed-off-by: NEric Paris <eparis@redhat.com>

include/linux/fanotify.h

@@ -65,14 +65,14 @@
 				 FAN_ALL_PERM_EVENTS |\
 				 FAN_Q_OVERFLOW)
 
-#define FANOTIFY_METADATA_VERSION	1
+#define FANOTIFY_METADATA_VERSION	2
 
 struct fanotify_event_metadata {
 	__u32 event_len;
 	__u32 vers;
-	__s32 fd;
 	__u64 mask;
-	__s64 pid;
+	__s32 fd;
+	__s32 pid;
 } __attribute__ ((packed));
 
 struct fanotify_response {