extern int td_io_prep(struct thread_data *, struct io_u *);
extern int td_io_queue(struct thread_data *, struct io_u *);
extern int td_io_sync(struct thread_data *, struct fio_file *);
extern int td_io_prep(struct thread_data *, struct io_u *);
extern int td_io_queue(struct thread_data *, struct io_u *);
extern int td_io_sync(struct thread_data *, struct fio_file *);