diff --git a/src/evalfunc.c b/src/evalfunc.c
index 1991aa7..25b28bb 100644
--- a/src/evalfunc.c
+++ b/src/evalfunc.c
@@ -13348,6 +13348,9 @@
 {
     int		binary = FALSE;
     int		append = FALSE;
+#ifdef HAVE_FSYNC
+    int		do_fsync = p_fs;
+#endif
     char_u	*fname;
     FILE	*fd;
     int		ret = 0;
@@ -13380,6 +13383,12 @@
 	    binary = TRUE;
 	if (vim_strchr(arg2, 'a') != NULL)
 	    append = TRUE;
+#ifdef HAVE_FSYNC
+	if (vim_strchr(arg2, 's') != NULL)
+	    do_fsync = TRUE;
+	else if (vim_strchr(arg2, 'S') != NULL)
+	    do_fsync = FALSE;
+#endif
     }
 
     fname = get_tv_string_chk(&argvars[1]);
@@ -13398,6 +13407,10 @@
     {
 	if (write_list(fd, list, binary) == FAIL)
 	    ret = -1;
+#ifdef HAVE_FSYNC
+	else if (do_fsync && fsync(fileno(fd)) != 0)
+	    EMSG(_(e_fsync));
+#endif
 	fclose(fd);
     }
 
diff --git a/src/fileio.c b/src/fileio.c
index fbc164a..e76e3d1 100644
--- a/src/fileio.c
+++ b/src/fileio.c
@@ -4771,7 +4771,7 @@
 	 */
 	if (p_fs && fsync(fd) != 0 && !device)
 	{
-	    errmsg = (char_u *)_("E667: Fsync failed");
+	    errmsg = (char_u *)_(e_fsync);
 	    end = 0;
 	}
 #endif
diff --git a/src/globals.h b/src/globals.h
index 3183632..ae62710 100644
--- a/src/globals.h
+++ b/src/globals.h
@@ -1449,6 +1449,9 @@
 #ifdef FEAT_LIBCALL
 EXTERN char_u e_libcall[]	INIT(= N_("E364: Library call failed for \"%s()\""));
 #endif
+#ifdef HAVE_FSYNC
+EXTERN char_u e_fsync[]		INIT(= N_("E667: Fsync failed"));
+#endif
 #if defined(DYNAMIC_PERL) \
 	|| defined(DYNAMIC_PYTHON) || defined(DYNAMIC_PYTHON3) \
 	|| defined(DYNAMIC_RUBY) \
diff --git a/src/testdir/test_writefile.vim b/src/testdir/test_writefile.vim
index f462d04..9703323b 100644
--- a/src/testdir/test_writefile.vim
+++ b/src/testdir/test_writefile.vim
@@ -93,3 +93,10 @@
   endif
   bwipe Xfile
 endfunc
+
+func Test_writefile_sync_arg()
+  " This doesn't check if fsync() works, only that the argument is accepted.
+  call writefile(['one'], 'Xtest', 's')
+  call writefile(['two'], 'Xtest', 'S')
+  call delete('Xtest')
+endfunc
diff --git a/src/version.c b/src/version.c
index 1dd52da..1cffd61 100644
--- a/src/version.c
+++ b/src/version.c
@@ -767,6 +767,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1305,
+/**/
     1304,
 /**/
     1303,