write_entry

# File activesupport/lib/active_support/cache/file_store.rb, line 88
        def write_entry(key, entry, options)
          file_name = key_file_path(key)
          ensure_cache_path(File.dirname(file_name))
          File.atomic_write(file_name, cache_path) {|f| Marshal.dump(entry, f)}
          true
        end