gfio: hold a reference to the fio_client structure

Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/client.h b/client.h
index e280adb..caeb432 100644
--- a/client.h
+++ b/client.h
@@ -115,6 +115,8 @@
 extern void fio_client_add_cmd_option(void *, const char *);
 extern void fio_client_terminate(struct fio_client *);
 extern void fio_clients_terminate(void);
+extern struct fio_client *fio_get_client(struct fio_client *);
+extern void fio_put_client(struct fio_client *);
 
 #endif