diff --git a/.gitmodules b/.gitmodules
index ad9a3025..9a58a7e9 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -4,3 +4,6 @@
 [submodule "ext/gmock"]
 	path = ext/gmock
 	url = https://github.com/google/googlemock.git
+[submodule "ext/gulrak-filesystem"]
+	path = ext/gulrak-filesystem
+	url = https://github.com/gulrak/filesystem
diff --git a/ext/gulrak-filesystem b/ext/gulrak-filesystem
new file mode 160000
index 00000000..614bbe87
--- /dev/null
+++ b/ext/gulrak-filesystem
@@ -0,0 +1 @@
+Subproject commit 614bbe87b80435d87ab8791564370e0c1d13627d