diff --git a/contrib/admin/main.php b/contrib/admin/main.php
index 88cfb9d1..ab902603 100644
--- a/contrib/admin/main.php
+++ b/contrib/admin/main.php
@@ -167,7 +167,7 @@ class AdminPage extends Extension {
 
 		$zip = new ZipArchive;
 		$images = $database->get_all("SELECT * FROM images");
-		$filename = 'data/imgdump-'.date('Ymd').'.zip';
+		$filename = data_path('imgdump-'.date('Ymd').'.zip');
 
 		if($zip->open($filename, 1 ? ZIPARCHIVE::OVERWRITE:ZIPARCHIVE::CREATE) === TRUE){
 			foreach($images as $img){
diff --git a/contrib/oekaki/main.php b/contrib/oekaki/main.php
index 2c534889..49e1e2cc 100644
--- a/contrib/oekaki/main.php
+++ b/contrib/oekaki/main.php
@@ -24,12 +24,10 @@ class Oekaki extends Extension {
 				if(isset($_FILES["picture"])) {
 					header('Content-type: text/plain');
 
-					$uploaddir = './data/oekaki_unclaimed/';
-					if(!file_exists($uploaddir)) mkdir($uploaddir, 0755, true);
 					$file = $_FILES['picture']['name'];
 					$ext = (strpos($file, '.') === FALSE) ? '' : substr($file, strrpos($file, '.'));
 					$uploadname = $_SERVER['REMOTE_ADDR'] . "." . time();
-					$uploadfile = $uploaddir . $uploadname;
+					$uploadfile = data_path('oekaki_unclaimed/'.$uploadname);
 
 					log_info("oekaki", "Uploading file [$uploadname]");
 
@@ -53,7 +51,7 @@ class Oekaki extends Extension {
 				// FIXME: move .chi to data/oekaki/$ha/$hash mirroring images and thumbs
 				// FIXME: .chi viewer?
 				// FIXME: clean out old unclaimed images?
-				$pattern = './data/oekaki_unclaimed/' . $_SERVER['REMOTE_ADDR'] . ".*.png";
+				$pattern = data_path('oekaki_unclaimed/' . $_SERVER['REMOTE_ADDR'] . ".*.png");
 				foreach(glob($pattern) as $tmpname) {
 					assert(file_exists($tmpname));
 
diff --git a/contrib/resize/main.php b/contrib/resize/main.php
index caba3ed4..139f3ca8 100644
--- a/contrib/resize/main.php
+++ b/contrib/resize/main.php
@@ -265,7 +265,6 @@ class ResizeImage extends Extension {
 		$new_hash = md5_file($tmp_filename);
 		$new_size = filesize($tmp_filename);
 		$target = warehouse_path("images", $new_hash);
-		if(!file_exists(dirname($target))) mkdir(dirname($target), 0755, true);
 		if(!@copy($tmp_filename, $target)) {
 			throw new ImageResizeException("Failed to copy new image file from temporary location ({$tmp_filename}) to archive ($target)");
 		}
diff --git a/contrib/update/main.php b/contrib/update/main.php
index 90372e42..9aad4c2c 100644
--- a/contrib/update/main.php
+++ b/contrib/update/main.php
@@ -91,7 +91,7 @@ class Update extends Extension {
 				$commit = $matches[2];
 				mkdir("./backup");
 				$html .= "<br>backup folder created!";
-				$d_dir = "data/cache";
+				$d_dir = data_path("cache");
 				//This should empty the /data/cache/ folder.
 				if (is_dir($d_dir)) {
 					$objects = scandir($d_dir);
diff --git a/core/imageboard.pack.php b/core/imageboard.pack.php
index 83a30d3a..e562de10 100644
--- a/core/imageboard.pack.php
+++ b/core/imageboard.pack.php
@@ -1080,7 +1080,6 @@ class Tag {
  */
 function move_upload_to_archive(DataUploadEvent $event) {
 	$target = warehouse_path("images", $event->hash);
-	if(!file_exists(dirname($target))) mkdir(dirname($target), 0755, true);
 	if(!@copy($event->tmpname, $target)) {
 		$errors = error_get_last(); // note: requires php 5.2
 		throw new UploadException("Failed to copy file from uploads ({$event->tmpname}) to archive ($target): {$errors['type']} / {$errors['message']}");
diff --git a/core/page.class.php b/core/page.class.php
index dae6dd9b..6a562f38 100644
--- a/core/page.class.php
+++ b/core/page.class.php
@@ -246,17 +246,13 @@ class Page {
 		$this->add_html_header("<link rel='icon' type='image/x-icon' href='$data_href/favicon.ico'>");
 		$this->add_html_header("<link rel='apple-touch-icon' href='$data_href/apple-touch-icon.png'>");
 
-		if(!file_exists("data/cache")) {
-			mkdir("data/cache");
-		}
-		
 		$css_files = array();
 		$css_latest = 0;
 		foreach(array_merge(zglob("lib/*.css"), zglob("ext/*/style.css"), zglob("themes/$theme_name/style.css")) as $css) {
 			$css_files[] = $css;
 			$css_latest = max($css_latest, filemtime($css));
 		}
-		$css_cache_file = "data/cache/style.$css_latest.css";
+		$css_cache_file = data_path("cache/style.$css_latest.css");
 		if(!file_exists($css_cache_file)) {
 			$css_data = "";
 			foreach($css_files as $file) {
@@ -276,7 +272,7 @@ class Page {
 			$js_files[] = $js;
 			$js_latest = max($js_latest, filemtime($js));
 		}
-		$js_cache_file = "data/cache/script.$js_latest.js";
+		$js_cache_file = data_path("cache/script.$js_latest.js");
 		if(!file_exists($js_cache_file)) {
 			$js_data = "";
 			foreach($js_files as $file) {
diff --git a/core/util.inc.php b/core/util.inc.php
index 2de968e1..8dff786e 100644
--- a/core/util.inc.php
+++ b/core/util.inc.php
@@ -645,6 +645,12 @@ function warehouse_path(/*string*/ $base, /*string*/ $hash, /*bool*/ $create=tru
 	return $pa;
 }
 
+function data_path($filename) {
+	$filename = "data/" . $filename;
+	if($create && !file_exists(dirname($filename))) mkdir(dirname($filename), 0755, true);
+	return $filename;
+}
+
 function transload($url, $mfile) {
 	global $config;
 
@@ -1075,10 +1081,7 @@ function _load_extensions() {
 			$p .= ");\n";
 
 			$p .= "?".">";
-			if(!file_exists("data/cache")) {
-				mkdir("data/cache", 755, true);
-			}
-			file_put_contents("data/cache/event_listeners.php", $p);
+			file_put_contents(data_path("cache/event_listeners.php"), $p);
 		}
 	}
 
@@ -1232,11 +1235,9 @@ function _start_cache() {
 			$_cache_hash = md5($_SERVER["QUERY_STRING"]);
 			$ab = substr($_cache_hash, 0, 2);
 			$cd = substr($_cache_hash, 2, 2);
-			$_cache_filename = "data/http_cache/$ab/$cd/$_cache_hash";
+			$_cache_filename = data_path("http_cache/$ab/$cd/$_cache_hash");
+			@chmod(data_path('http_cache'), 750);
 
-			if(!file_exists(dirname($_cache_filename))) {
-				mkdir(dirname($_cache_filename), 0750, true);
-			}
 			if(file_exists($_cache_filename) && (filemtime($_cache_filename) > time() - 3600)) {
 				$gmdate_mod = gmdate('D, d M Y H:i:s', filemtime($_cache_filename)) . ' GMT';