+ unsigned int resid;
+ unsigned int error;
+
+ /*
+ * io engine private data
+ */
+ union {
+ unsigned int index;
+ unsigned int seen;
+ void *engine_data;
+ };
+
+ struct flist_head verify_list;
+
+ /*
+ * Callback for io completion
+ */
+ int (*end_io)(struct thread_data *, struct io_u *);
+