diff --git a/lib/filestorage/file_packer.php b/lib/filestorage/file_packer.php
index ad8e8c4aa25..76aeead83ca 100644
--- a/lib/filestorage/file_packer.php
+++ b/lib/filestorage/file_packer.php
@@ -63,9 +63,10 @@ abstract class file_packer {
      *
      * @param stored_file|string $archivefile full pathname of zip file or stored_file instance
      * @param string $pathname target directory
+     * @param array $onlyfiles only extract files present in the array
      * @return array|bool list of processed files; false if error
      */
-    public abstract function extract_to_pathname($archivefile, $pathname);
+    public abstract function extract_to_pathname($archivefile, $pathname, array $onlyfiles = NULL);
 
     /**
      * Extract file to given file path (real OS filesystem), existing files are overwrited
diff --git a/lib/filestorage/tests/zip_packer_test.php b/lib/filestorage/tests/zip_packer_test.php
index ed0ff8e7eee..1d3e278587a 100644
--- a/lib/filestorage/tests/zip_packer_test.php
+++ b/lib/filestorage/tests/zip_packer_test.php
@@ -226,6 +226,46 @@ class zip_packer_testcase extends advanced_testcase {
         }
     }
 
+    /**
+     * @depends test_archive_to_storage
+     */
+    public function test_extract_to_pathname_onlyfiles() {
+        global $CFG;
+
+        $this->resetAfterTest(false);
+
+        $packer = get_file_packer('application/zip');
+        $fs = get_file_storage();
+        $context = context_system::instance();
+
+        $target = "$CFG->tempdir/onlyfiles/";
+        $testcontent = file_get_contents($this->testfile);
+
+        @mkdir($target, $CFG->directorypermissions);
+        $this->assertTrue(is_dir($target));
+
+        $onlyfiles = array('test', 'test.test', 'Žluťoučký/Koníček.txt', 'Idontexist');
+        $willbeextracted = array_intersect(array_keys($this->files), $onlyfiles);
+        $donotextract = array_diff(array_keys($this->files), $onlyfiles);
+
+        $archive = "$CFG->tempdir/archive.zip";
+        $this->assertTrue(file_exists($archive));
+        $result = $packer->extract_to_pathname($archive, $target, $onlyfiles);
+        $this->assertTrue(is_array($result));
+        $this->assertEquals(count($willbeextracted), count($result));
+
+        foreach($willbeextracted as $file) {
+            $this->assertTrue($result[$file]);
+            $this->assertTrue(file_exists($target.$file));
+            $this->assertSame($testcontent, file_get_contents($target.$file));
+        }
+        foreach($donotextract as $file) {
+            $this->assertFalse(isset($result[$file]));
+            $this->assertFalse(file_exists($target.$file));
+        }
+
+    }
+
     /**
      * @depends test_archive_to_storage
      */
diff --git a/lib/filestorage/zip_packer.php b/lib/filestorage/zip_packer.php
index 90afe711a7d..dcfba55cb55 100644
--- a/lib/filestorage/zip_packer.php
+++ b/lib/filestorage/zip_packer.php
@@ -218,9 +218,11 @@ class zip_packer extends file_packer {
      * @todo MDL-31048 localise messages
      * @param string|stored_file $archivefile full pathname of zip file or stored_file instance
      * @param string $pathname target directory
+     * @param array $onlyfiles only extract files present in the array. The path to files MUST NOT
+     *              start with a /. Example: array('myfile.txt', 'directory/anotherfile.txt')
      * @return bool|array list of processed files; false if error
      */
-    public function extract_to_pathname($archivefile, $pathname) {
+    public function extract_to_pathname($archivefile, $pathname, array $onlyfiles = null) {
         global $CFG;
 
         if (!is_string($archivefile)) {
@@ -233,7 +235,7 @@ class zip_packer extends file_packer {
         if (!is_readable($archivefile)) {
             return false;
         }
-       $ziparch = new zip_archive();
+        $ziparch = new zip_archive();
         if (!$ziparch->open($archivefile, file_archive::OPEN)) {
             return false;
         }
@@ -243,7 +245,10 @@ class zip_packer extends file_packer {
             $name = $info->pathname;
 
             if ($name === '' or array_key_exists($name, $processed)) {
-                //probably filename collisions caused by filename cleaning/conversion
+                // Probably filename collisions caused by filename cleaning/conversion.
+                continue;
+            } else if (is_array($onlyfiles) && !in_array($name, $onlyfiles)) {
+                // Skipping files which are not in the list.
                 continue;
             }