diff --git a/arch/um/os-Linux/file.c b/arch/um/os-Linux/file.c
index 07a7501..08d90fb 100644
--- a/arch/um/os-Linux/file.c
+++ b/arch/um/os-Linux/file.c
@@ -237,6 +237,12 @@
 {
 	close(fd);
 }
+int os_fsync_file(int fd)
+{
+	if (fsync(fd) < 0)
+	    return -errno;
+	return 0;
+}
 
 int os_seek_file(int fd, unsigned long long offset)
 {