diff --git a/lib/gollum/committer.rb b/lib/gollum/committer.rb
index 04baa314..002a9531 100644
--- a/lib/gollum/committer.rb
+++ b/lib/gollum/committer.rb
@@ -118,7 +118,7 @@ module Gollum
     def update_working_dir(dir, name, format)
       unless @wiki.repo.bare
         if @wiki.page_file_dir
-          dir = dir.size.zero? ? @wiki.page_file_dir : File.join(dir, @wiki.page_file_dir)
+          dir = dir.size.zero? ? @wiki.page_file_dir : ::File.join(dir, @wiki.page_file_dir)
         end
 
         path =
diff --git a/test/test_wiki.rb b/test/test_wiki.rb
index e34cc542..5b9b486c 100644
--- a/test/test_wiki.rb
+++ b/test/test_wiki.rb
@@ -282,6 +282,11 @@ context "page_file_dir option" do
     assert_equal "Hi", File.read(File.join(@path, @page_file_dir, "New-Page.md"))
     assert !File.exist?(File.join(@path, "New-Page.md"))
   end
+  
+  test "edit a page in a sub directory" do
+    page = @wiki.page('foo')
+    @wiki.update_page(page, page.name, page.format, 'new contents', commit_details)
+  end
 
   test "a file in page file dir should be found" do
     assert @wiki.page("foo")