nilfs_find_entry
de = nilfs_find_entry(dir, qstr, &folio);
de = nilfs_find_entry(dir, &dentry->d_name, &folio);
old_de = nilfs_find_entry(old_dir, &old_dentry->d_name, &old_folio);
new_de = nilfs_find_entry(new_dir, &new_dentry->d_name,
struct nilfs_dir_entry *nilfs_find_entry(struct inode *, const struct qstr *,