From: sf <sf@openbsd.org>
Date: Mon, 29 May 2017 14:08:49 +0000 (+0000)
Subject: sd: flush cache when closing writable FD
X-Git-Url: http://artulab.com/gitweb/?a=commitdiff_plain;h=3c102e39dd4a727213d3cd2193bdec3bebab0fa3;p=openbsd

sd: flush cache when closing writable FD

Don't skip the cache flush until the last opening of the device is
closed. Otherwise, when umounting a writable partition while a different
partition is still mounted read-only, the necessary disk flush may be
delayed for a very long time.

ok krw@ deraadt@
---

diff --git a/sys/scsi/sd.c b/sys/scsi/sd.c
index 0a26c87581c..5869d6fdb17 100644
--- a/sys/scsi/sd.c
+++ b/sys/scsi/sd.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: sd.c,v 1.272 2017/05/29 14:05:31 sf Exp $	*/
+/*	$OpenBSD: sd.c,v 1.273 2017/05/29 14:08:49 sf Exp $	*/
 /*	$NetBSD: sd.c,v 1.111 1997/04/02 02:29:41 mycroft Exp $	*/
 
 /*-
@@ -511,10 +511,11 @@ sdclose(dev_t dev, int flag, int fmt, struct proc *p)
 
 	disk_closepart(&sc->sc_dk, part, fmt);
 
-	if (sc->sc_dk.dk_openmask == 0) {
-		if ((sc->flags & SDF_DIRTY) != 0)
-			sd_flush(sc, 0);
+	if (((flag & FWRITE) != 0 || sc->sc_dk.dk_openmask == 0) &&
+	    (sc->flags & SDF_DIRTY) != 0)
+		sd_flush(sc, 0);
 
+	if (sc->sc_dk.dk_openmask == 0) {
 		if (sc->flags & SDF_DYING) {
 			error = ENXIO;
 			goto die;