src/Routing/Routes.php | 19 +++++++++++++------
 1 file changed, 13 insertions(+), 6 deletions(-)

diff --git a/src/Routing/Routes.php b/src/Routing/Routes.php
index fd6b81d..ec5fa5a 100644
--- a/src/Routing/Routes.php
+++ b/src/Routing/Routes.php
@@ -231,13 +231,15 @@ class Routes implements ContainerInjectionInterface {
         $new_resource_file_upload_route->addDefaults([RouteObjectInterface::CONTROLLER_NAME => 'jsonapi.file_upload:handleFileUploadForNewResource']);
         $new_resource_file_upload_route->setMethods(['POST']);
         $new_resource_file_upload_route->setRequirement('_csrf_request_header_token', 'TRUE');
-        $routes->add(static::getFileUploadRouteName($resource_type, 'new_resource'), $new_resource_file_upload_route);
+        $new_resource_file_upload_route->setDefault('file_field_name', $relationship_field_name);
+        $routes->add(static::getFileUploadRouteName($resource_type, $relationship_field_name, 'new_resource'), $new_resource_file_upload_route);
 
         $existing_resource_file_upload_route = new Route("/{$path}/{entity}/{$relationship_field_name}");
         $existing_resource_file_upload_route->addDefaults([RouteObjectInterface::CONTROLLER_NAME => 'jsonapi.file_upload:handleFileUploadForExistingResource']);
         $existing_resource_file_upload_route->setMethods(['POST']);
         $existing_resource_file_upload_route->setRequirement('_csrf_request_header_token', 'TRUE');
-        $routes->add(static::getFileUploadRouteName($resource_type, 'existing_resource'), $existing_resource_file_upload_route);
+        $existing_resource_file_upload_route->setDefault('file_field_name', $relationship_field_name);
+        $routes->add(static::getFileUploadRouteName($resource_type, $relationship_field_name, 'existing_resource'), $existing_resource_file_upload_route);
 
         // Add entity parameter conversion to every route.
         $routes->addOptions(['parameters' => ['entity' => ['type' => 'entity:' . $entity_type_id]]]);
@@ -413,15 +415,20 @@ class Routes implements ContainerInjectionInterface {
    * Get a unique route name for the file upload resource type and route type.
    *
    * @param \Drupal\jsonapi\ResourceType\ResourceType $resource_type
-   *   The resource type for which the route collection should be created.
+   *   The resource type for which the file upload route should be created.
+   * @param string $file_field_name
+   *   The file field for which the file upload route should be created.
    * @param string $route_type
-   *   The route type. E.g. 'individual' or 'collection'.
+   *   The route type. E.g. 'new_resource' or 'existing_resource'.
    *
    * @return string
    *   The generated route name.
+   *
+   * @todo remove this in favor of getroutename
    */
-  protected static function getFileUploadRouteName(ResourceType $resource_type, $route_type) {
-    return sprintf('jsonapi.%s.%s.%s', $resource_type->getTypeName(), 'file_upload', $route_type);
+  protected static function getFileUploadRouteName(ResourceType $resource_type, $file_field_name, $route_type) {
+    assert($route_type === 'new_resource' || $route_type === 'existing_resource');
+    return sprintf('jsonapi.%s.%s.%s.%s', $resource_type->getTypeName(), $file_field_name, 'file_upload', $route_type);
   }
 
   /**