# File lib/mongo/gridfs/grid.rb, line 72
    def put(data, opts={})
      opts     = opts.dup
      filename = opts.delete(:filename)
      opts.merge!(default_grid_io_opts)
      file = GridIO.new(@files, @chunks, filename, 'w', opts)
      file.write(data)
      file.close  
      file.files_id
    end