diff --git a/core/lib/Drupal/Core/Config/CachedStorage.php b/core/lib/Drupal/Core/Config/CachedStorage.php
index cfb06ce..7253b54 100644
--- a/core/lib/Drupal/Core/Config/CachedStorage.php
+++ b/core/lib/Drupal/Core/Config/CachedStorage.php
@@ -97,8 +97,8 @@ public function readMultiple(array $names) {
     $cids = $this->getCacheKeys($names);
     $cached_list = $this->cache->getMultiple($cids);
 
-    if (!empty($names)) {
-      $list = $this->storage->readMultiple($names);
+    if (!empty($cids)) {
+      $list = $this->storage->readMultiple(array_keys($cids));
       // Cache configuration objects that were loaded from the storage, cache
       // missing configuration objects as an explicit FALSE.
       foreach ($names as $name) {
@@ -275,4 +275,14 @@ protected function getCacheKeys(array $names) {
     return $cids;
   }
 
+  /**
+   * Set the cache prefix used by this storage.
+   *
+   * @param string $cachePrefix
+   *   Name of the prefix that should be used for all cache IDs.
+   */
+  public function setCachePrefix($cachePrefix) {
+    $this->cachePrefix = $cachePrefix;
+  }
+
 }
diff --git a/core/lib/Drupal/Core/Config/ConfigInstaller.php b/core/lib/Drupal/Core/Config/ConfigInstaller.php
index ec2d2f2..d1197d7 100644
--- a/core/lib/Drupal/Core/Config/ConfigInstaller.php
+++ b/core/lib/Drupal/Core/Config/ConfigInstaller.php
@@ -138,12 +138,12 @@ public function installDefaultConfig($type, $name) {
       // Remove configuration that already exists in the active storage.
       $sorted_config = array_diff($sorted_config, $this->activeStorage->listAll());
 
-      foreach ($sorted_config as $name) {
-        $new_config = new Config($name, $this->activeStorage, $this->eventDispatcher, $this->typedConfig);
-        if ($data[$name] !== FALSE) {
-          $new_config->setData($data[$name]);
+      foreach ($sorted_config as $config_name) {
+        $new_config = new Config($config_name, $this->activeStorage, $this->eventDispatcher, $this->typedConfig);
+        if ($data[$config_name] !== FALSE) {
+          $new_config->setData($data[$config_name]);
         }
-        if ($entity_type = $this->configManager->getEntityTypeIdByName($name)) {
+        if ($entity_type = $this->configManager->getEntityTypeIdByName($config_name)) {
 
           // If we are syncing do not create configuration entities. Pluggable
           // configuration entities can have dependencies on modules that are
@@ -159,8 +159,8 @@ public function installDefaultConfig($type, $name) {
             ->getStorage($entity_type);
           // It is possible that secondary writes can occur during configuration
           // creation. Updates of such configuration are allowed.
-          if ($this->activeStorage->exists($name)) {
-            $id = $entity_storage->getIDFromConfigName($name, $entity_storage->getEntityType()->getConfigPrefix());
+          if ($this->activeStorage->exists($config_name)) {
+            $id = $entity_storage->getIDFromConfigName($config_name, $entity_storage->getEntityType()->getConfigPrefix());
             $entity = $entity_storage->load($id);
             foreach ($new_config->get() as $property => $value) {
               $entity->set($property, $value);
diff --git a/core/modules/language/lib/Drupal/language/Config/LanguageConfigFactoryOverride.php b/core/modules/language/lib/Drupal/language/Config/LanguageConfigFactoryOverride.php
index 9a1eb2e..37bdf9e 100644
--- a/core/modules/language/lib/Drupal/language/Config/LanguageConfigFactoryOverride.php
+++ b/core/modules/language/lib/Drupal/language/Config/LanguageConfigFactoryOverride.php
@@ -80,7 +80,7 @@ public function loadOverrides($names) {
   public function getOverride($langcode, $name) {
     $storage = clone $this->storage;
     $data = $storage->setLangcode($langcode)->read($name);
-    $override = new LanguageConfigOverride($name, $this->storage, $this->typedConfigManager);
+    $override = new LanguageConfigOverride($name, $storage, $this->typedConfigManager);
     if (!empty($data)) {
       $override->initWithData($data);
     }
diff --git a/core/modules/language/lib/Drupal/language/Config/LanguageOverrideCachedStorage.php b/core/modules/language/lib/Drupal/language/Config/LanguageOverrideCachedStorage.php
index 40983d6..4026102 100644
--- a/core/modules/language/lib/Drupal/language/Config/LanguageOverrideCachedStorage.php
+++ b/core/modules/language/lib/Drupal/language/Config/LanguageOverrideCachedStorage.php
@@ -43,4 +43,13 @@ public function setLangcode($langcode) {
     return $this;
   }
 
+  /**
+   * {@inheritdoc}
+   */
+  function __clone() {
+    // Also clone the inner storage, so that language code changes work as
+    // expected.
+    $this->storage = clone $this->storage;
+  }
+
 }
diff --git a/core/tests/Drupal/Tests/Core/Config/CachedStorageTest.php b/core/tests/Drupal/Tests/Core/Config/CachedStorageTest.php
index 6c60af4..c7d8dc3 100644
--- a/core/tests/Drupal/Tests/Core/Config/CachedStorageTest.php
+++ b/core/tests/Drupal/Tests/Core/Config/CachedStorageTest.php
@@ -84,6 +84,33 @@ public function testGetMultipleOnPrimedCache() {
   }
 
   /**
+   * Test that the cache prefix is used correctly.
+   */
+  public function testGetMultipleCachePrefix() {
+    $configNames = array(
+      'foo.bar',
+      'baz.back',
+    );
+    $configCacheValues = array(
+      'prefix:foo.bar' => array(
+        'foo' => 'bar',
+      ),
+      'prefix:baz.back' => array(
+        'foo' => 'bar',
+      ),
+    );
+    $storage = $this->getMock('Drupal\Core\Config\StorageInterface');
+    $storage->expects($this->never())->method('readMultiple');
+    $cache = new MemoryBackend(__FUNCTION__);
+    foreach ($configCacheValues as $key => $value) {
+      $cache->set($key, $value);
+    }
+    $cachedStorage = new CachedStorage($storage, $cache);
+    $cachedStorage->setCachePrefix('prefix');
+    $this->assertEquals($configCacheValues, $cachedStorage->readMultiple($configNames));
+  }
+
+  /**
    * Test fall through to file storage in CachedStorage::readMulitple().
    */
   public function testGetMultipleOnPartiallyPrimedCache() {
@@ -116,7 +143,7 @@ public function testGetMultipleOnPartiallyPrimedCache() {
     $storage = $this->getMock('Drupal\Core\Config\StorageInterface');
     $storage->expects($this->once())
       ->method('readMultiple')
-      ->with(array(2 => $configNames[2], 4 => $configNames[4]))
+      ->with(array($configNames[2], $configNames[4]))
       ->will($this->returnValue($response));
 
     $cachedStorage = new CachedStorage($storage, $cache);