--- convert/source-fs.h.orig	2017-09-08 14:20:05.000000000 +0000
+++ convert/source-fs.h	2017-09-09 08:48:46.648264368 +0000
@@ -20,6 +20,7 @@
 #include "kerncompat.h"
 #include <linux/kdev_t.h>
 #include <pthread.h>
+#include <sys/types.h>
 
 #define CONV_IMAGE_SUBVOL_OBJECTID BTRFS_FIRST_FREE_OBJECTID