text: #include <linux/fs.h>
  
  struct address_space_operations moon_add_ops = {
  	.readpage	= simple_readpage,
  	.write_begin	= simple_write_begin,
  	.write_end	= simple_write_end,
  };
  
  struct file_operations moon_file_operations = {
  	.read_iter	= generic_file_read_iter,
  	.write_iter	= generic_file_write_iter,
  	.mmap		= generic_file_mmap,
  	.fsync		= noop_fsync,
  	.llseek		= generic_file_llseek,
  };
  