Only call into log_io_piece() when verify is set

Don't know why it currently always logs the IO, it's pretty
pointless.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/io_u.c b/io_u.c
index 9c8ff26..0580f42 100644
--- a/io_u.c
+++ b/io_u.c
@@ -660,7 +660,8 @@
 		add_bw_sample(td, idx, &icd->time);
 		io_u_mark_latency(td, msec);
 
-		if ((td_rw(td) || td_write(td)) && idx == DDIR_WRITE)
+		if ((td_rw(td) || td_write(td)) && idx == DDIR_WRITE &&
+		    td->o.verify != VERIFY_NONE)
 			log_io_piece(td, io_u);
 
 		icd->bytes_done[idx] += bytes;