url_for not matching route

My routes.rb looks like this:

namespace :workflow do

resources :articles, :except => [:index, :new, :create] do
  resources :revisions, :controller => "articles/revisions" do
    get 'body', :on => :member
  end
end

end

When I call body_workflow_article_revision in my view, it raises an ActionController::RoutingError:
No route matches {:controller=>"workflow/articles/revisions", :action=>"body"} The same thing happens when I try using url_for.