Index: wp-includes/ms-functions.php
===================================================================
--- wp-includes/ms-functions.php	(revision 28222)
+++ wp-includes/ms-functions.php	(working copy)
@@ -2292,8 +2292,14 @@
 		$upload_dir = wp_upload_dir();
 		$space_used = get_dirsize( $upload_dir['basedir'] ) / 1024 / 1024;
 	}
-
-	return $space_used;
+	/**
+	 * Filter the amount of storage space used by the current site after default calculations have been applied.
+	 *
+	 * @since 3.9.1
+	 *
+	 * @param int $space_used The amount of used space, in megabytes.
+	 */
+	return apply_filters( 'get_space_used', $space_used );
 }
 
 /**
Index: .
===================================================================
--- .	(revision 28222)
+++ .	(working copy)

Property changes on: .
___________________________________________________________________
Added: svn:ignore
## -0,0 +1 ##
+.idea