Keep Grack::Auth in the routes for LFS only

config/routes.rb

@@ -59,6 +59,9 @@ Rails.application.routes.draw do
     mount Sidekiq::Web, at: '/admin/sidekiq', as: :sidekiq
   end
 
+  # Enable Grack support (for LFS only)
+  mount Grack::AuthSpawner, at: '/', constraints: lambda { |request| /[-\/\w\.]+\.git\/(info\/lfs|gitlab-lfs)/.match(request.path_info) }, via: [:get, :post, :put]
+
   # Help
   get 'help'                  => 'help#index'
   get 'help/:category/:file'  => 'help#show', as: :help_page, constraints: { category: /.*/, file: /[^\/\.]+/ }