From: Jason Dillaman <dillaman@redhat.com>
Date: Wed, 2 Dec 2020 19:03:42 +0000 (-0500)
Subject: engines/rbd: issue initial flush to enable writeback/around mode
X-Git-Tag: fio-3.26~77^2
X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=8e4e151fe1f7e2548c4de268e085634696db4cb1;p=fio.git

engines/rbd: issue initial flush to enable writeback/around mode

By default librbd will use a writethrough cache until it receives
the first flush. Send a no-op flush after opening the image to
ensure writearound (default) or writeback cache modes can be
properly enabled (unlesss direct=1).

Signed-off-by: Jason Dillaman <dillaman@redhat.com>
---

diff --git a/engines/rbd.c b/engines/rbd.c
index 336837e9..c6203d4c 100644
--- a/engines/rbd.c
+++ b/engines/rbd.c
@@ -240,6 +240,17 @@ static int _fio_rbd_connect(struct thread_data *td)
 		goto failed_open;
 	}
 
+	if (!td->o.odirect) {
+		/*
+		 * ensure cache enables writeback/around mode unless explicitly
+		 * configured for writethrough mode
+		 */
+		r = rbd_flush(rbd->image);
+		if (r < 0) {
+			log_info("rbd: failed to issue initial flush\n");
+		}
+	}
+
 	if (!_fio_rbd_setup_poll(rbd))
 		goto failed_poll;