Propagate io engine error back to 'td', if not already done

Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/ioengines.c b/ioengines.c
index 93e7631..d71e372 100644
--- a/ioengines.c
+++ b/ioengines.c
@@ -288,6 +288,13 @@
 	unlock_file(td, io_u->file);
 
 	/*
+	 * If an error was seen and the io engine didn't propagate it
+	 * back to 'td', do so.
+	 */
+	if (io_u->error && !td->error)
+		td_verror(td, io_u->error, "td_io_queue");
+
+	/*
 	 * Add warning for O_DIRECT so that users have an easier time
 	 * spotting potentially bad alignment. If this triggers for the first
 	 * IO, then it's likely an alignment problem or because the host fs