read_absolute_file_path_from_dentry
size_t len = read_absolute_file_path_from_dentry(filp_dentry, payload);
size_t len = read_absolute_file_path_from_dentry(old_dentry, payload);
len = read_absolute_file_path_from_dentry(new_dentry, payload);
len = read_absolute_file_path_from_dentry(dentry, payload);