#include <linux/module.h>
  #include <linux/fs.h>
  #include <linux/fs_stack.h>
  
  /* does _NOT_ require i_mutex to be held.
   *
   * This function cannot be inlined since i_size_{read,write} is rather
   * heavy-weight on 32-bit systems
   */
  void fsstack_copy_inode_size(struct inode *dst, const struct inode *src)
  {
  	i_size_write(dst, i_size_read((struct inode *)src));
  	dst->i_blocks = src->i_blocks;
  }
  EXPORT_SYMBOL_GPL(fsstack_copy_inode_size);
  
  /* copy all attributes; get_nlinks is optional way to override the i_nlink
   * copying
   */
  void fsstack_copy_attr_all(struct inode *dest, const struct inode *src,
  				int (*get_nlinks)(struct inode *))
  {

  	dest->i_mode = src->i_mode;
  	dest->i_uid = src->i_uid;
  	dest->i_gid = src->i_gid;
  	dest->i_rdev = src->i_rdev;
  	dest->i_atime = src->i_atime;
  	dest->i_mtime = src->i_mtime;
  	dest->i_ctime = src->i_ctime;
  	dest->i_blkbits = src->i_blkbits;
  	dest->i_flags = src->i_flags;

  
  	/*
  	 * Update the nlinks AFTER updating the above fields, because the
  	 * get_links callback may depend on them.
  	 */
  	if (!get_nlinks)
  		dest->i_nlink = src->i_nlink;
  	else
  		dest->i_nlink = (*get_nlinks)(dest);

  }
  EXPORT_SYMBOL_GPL(fsstack_copy_attr_all);