diff --git a/core/lib/Drupal/Core/Entity/ContentEntityStorageBase.php b/core/lib/Drupal/Core/Entity/ContentEntityStorageBase.php
index 04a6d8c..ba54f66 100644
--- a/core/lib/Drupal/Core/Entity/ContentEntityStorageBase.php
+++ b/core/lib/Drupal/Core/Entity/ContentEntityStorageBase.php
@@ -289,18 +289,39 @@ protected function doSave($id, EntityInterface $entity) {
    */
   protected function doPreSave(EntityInterface $entity) {
     /** @var \Drupal\Core\Entity\ContentEntityBase $entity */
-
     // Sync the changes made in the fields array to the internal values array.
     $entity->updateOriginalValues();
 
-    $return = parent::doPreSave($entity);
+    $id = $entity->id();
+
+    // Track the original ID.
+    if ($entity->getOriginalId() !== NULL) {
+      $id = $entity->getOriginalId();
+    }
+
+    // Track if this entity exists already.
+    $id_exists = $this->has($id, $entity);
+
+    // A new entity should not already exist.
+    if ($id_exists && $entity->isNew()) {
+      throw new EntityStorageException("'{$this->entityTypeId}' entity with ID '$id' already exists.");
+    }
+
+    // Load the original entity, if any.
+    if ($id_exists && !isset($entity->original)) {
+      $entity->original = $this->loadUnchanged($id);
+    }
 
     // Reset the persistent cache if this entity type uses it.
     if (!$entity->isNew() && $this->entityType->isPersistentlyCacheable()) {
       $this->cacheBackend->delete($this->buildCacheId($entity->id()));
     }
 
-    return $return;
+    // Allow code to run before saving.
+    $entity->preSave($this);
+    $this->invokeHook('presave', $entity);
+
+    return $id;
   }
 
   /**