diff --git a/cache_filesystem.go b/cache_filesystem.go
index a5bcb1e..196ffb4 100644
--- a/cache_filesystem.go
+++ b/cache_filesystem.go
@@ -26,15 +26,15 @@ func filesystemCache(center s2.LatLng, zoom int, marker []marker, x, y int) (io.
 	}
 
 	buf := new(bytes.Buffer)
-	if _, err := io.Copy(buf, mapReader); err != nil {
+	if _, err = io.Copy(buf, mapReader); err != nil {
 		return nil, err
 	}
 
-	if err := os.MkdirAll(path.Dir(cacheFileName), 0755); err != nil {
+	if err = os.MkdirAll(path.Dir(cacheFileName), 0700); err != nil {
 		return nil, err
 	}
 
-	if err := ioutil.WriteFile(cacheFileName, buf.Bytes(), 0644); err != nil {
+	if err = ioutil.WriteFile(cacheFileName, buf.Bytes(), 0644); err != nil {
 		return nil, err
 	}
 
diff --git a/main.go b/main.go
index 9846016..7a2fd9c 100644
--- a/main.go
+++ b/main.go
@@ -91,7 +91,7 @@ func handleMapRequest(res http.ResponseWriter, r *http.Request) {
 	}
 
 	if mapReader, err = cacheFunc(*center, zoom, markers, x, y); err != nil {
-		log.Error("Map render failed: %s (Request: %s)", err, r.URL.String())
+		log.Errorf("Map render failed: %s (Request: %s)", err, r.URL.String())
 		http.Error(res, fmt.Sprintf("I experienced difficulties rendering your map: %s", err), http.StatusInternalServerError)
 		return
 	}