Index: wp-includes/formatting.php
===================================================================
--- wp-includes/formatting.php	(revision 17488)
+++ wp-includes/formatting.php	(working copy)
@@ -734,6 +734,53 @@
 }
 
 /**
+ * Remove dot segments from a path
+ *
+ * @aince 3.2
+ *
+ * @param string $input The string to remove dot segments from
+ * @return string
+ */
+function remove_dot_segments( $input ) {
+	$output = '';
+	while ( false !== strpos( $input, './' ) || false !== strpos( $input, '/.' ) || '.' === $input || '..' === $input ) {
+		// A: If the input buffer begins with a prefix of "../" or "./", then remove that prefix from the input buffer; otherwise,
+		if ( 0 === strpos( $input, '../' ) ) {
+			$input = substr( $input, 3 );
+		} elseif ( 0 === strpos( $input, './' ) ) {
+			$input = substr( $input, 2 );
+		}
+		// B: if the input buffer begins with a prefix of "/./" or "/.", where "." is a complete path segment, then replace that prefix with "/" in the input buffer; otherwise,
+		elseif ( 0 === strpos( $input, '/./' ) ) {
+			$input = substr_replace( $input, '/', 0, 3 );
+		} elseif ( '/.' === $input ) {
+			$input = '/';
+		}
+		// C: if the input buffer begins with a prefix of "/../" or "/..", where ".." is a complete path segment, then replace that prefix with "/" in the input buffer and remove the last segment and its preceding "/" (if any) from the output buffer; otherwise,
+		elseif ( 0 === strpos( $input, '/../' ) ) {
+			$input = substr_replace( $input, '/', 0, 4 );
+			$output = substr_replace( $output, '', strrpos( $output, '/' ) );
+		} elseif ( '/..' === $input ) {
+			$input = '/';
+			$output = substr_replace( $output, '', strrpos( $output, '/' ) );
+		}
+		// D: if the input buffer consists only of "." or "..", then remove that from the input buffer; otherwise,
+		elseif ( '.' === $input || '..' === $input ) {
+			$input = '';
+		}
+		// E: move the first path segment in the input buffer to the end of the output buffer, including the initial "/" character (if any) and any subsequent characters up to, but not including, the next "/" character or the end of the input buffer
+		elseif ( false !== ( $pos = strpos( $input, '/', 1 ) ) ) {
+			$output .= substr( $input, 0, $pos );
+			$input = substr_replace( $input, '', 0, $pos );
+		} else {
+			$output .= $input;
+			$input = '';
+		}
+	}
+	return $output . $input;
+}
+
+/**
  * Sanitize username stripping out unsafe characters.
  *
  * Removes tags, octets, entities, and if strict is enabled, will only keep
Index: wp-includes/general-template.php
===================================================================
--- wp-includes/general-template.php	(revision 17488)
+++ wp-includes/general-template.php	(working copy)
@@ -116,16 +116,34 @@
  * @param string $slug The slug name for the generic template.
  * @param string $name The name of the specialised template.
  */
-function get_template_part( $slug, $name = null ) {
-	do_action( "get_template_part_{$slug}", $slug, $name );
+function get_template_part( $slug, $name = null, $directory = null ) {
+	if ( false !== strpos( $slug, DIRECTORY_SEPARATOR ) ) {
+		$original_slug = $slug;
+		$slug = substr( strrchr( $slug, DIRECTORY_SEPARATOR ), 1 );
+		if ( empty( $directory ) ) {
+			$directory = substr( $original_slug, 0, strrpos( $original_slug, DIRECTORY_SEPARATOR ) );
+		}
+	}
+	$slug = sanitize_file_name( $slug );
 
+	$directory = rtrim( remove_dot_segments( $directory ), DIRECTORY_SEPARATOR );
+
+	do_action( "get_template_part_{$slug}", $slug, $name, $directory );
+
 	$templates = array();
+	if ( ! empty( $directory ) ) {
+		if ( isset($name) )
+			$templates[] = $directory . DIRECTORY_SEPARATOR . "{$slug}-{$name}.php";
+
+		$templates[] = $directory . DIRECTORY_SEPARATOR . "{$slug}.php";
+	}
+
 	if ( isset($name) )
 		$templates[] = "{$slug}-{$name}.php";
 
 	$templates[] = "{$slug}.php";
 
-	locate_template($templates, true, false);
+	locate_template( $templates, true, false );
 }
 
 /**