svn commit: r207936 - head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs

[Pawel Jakub Dawidek]

Author: pjd
Date: Tue May 11 22:29:00 2010
New Revision: 207936
URL: http://svn.freebsd.org/changeset/base/207936

Log:
  Eventhough r203504 eliminates taste traffic provoked by vdev_geom.c,
  ZFS still like to open all vdevs, close them and open them again,
  which in turn provokes taste traffic anyway.
  
  I don't know of any clean way to fix it, so do it the hard way - if we can't
  open provider for writing just retry 5 times with 0.5 pauses. This should
  elimitate accidental races caused by other classes tasting providers created on
  top of our vdevs.
  
  MFC after:	3 days
  Reported by:	James R. Van Artsdalen <james-freebsd-fs2 at jrv.org>
  Reported by:	Yuri Pankov <yuri.pankov at gmail.com>

Modified:
  head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/vdev_geom.c

Modified: head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/vdev_geom.c
==============================================================================
--- head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/vdev_geom.c	Tue May 11 22:28:55 2010	(r207935)
+++ head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/vdev_geom.c	Tue May 11 22:29:00 2010	(r207936)
@@ -530,8 +530,17 @@ vdev_geom_open(vdev_t *vd, uint64_t *psi
 		ZFS_LOG(1, "Provider %s not found.", vd->vdev_path);
 		error = ENOENT;
 	} else if (cp->acw == 0 && (spa_mode & FWRITE) != 0) {
+		int i;
+
 		g_topology_lock();
-		error = g_access(cp, 0, 1, 0);
+		for (i = 0; i < 5; i++) {
+			error = g_access(cp, 0, 1, 0);
+			if (error == 0)
+				break;
+			g_topology_unlock();
+			tsleep(vd, 0, "vdev", hz / 2);
+			g_topology_lock();
+		}
 		if (error != 0) {
 			printf("ZFS WARNING: Unable to open %s for writing (error=%d).\n",
 			    vd->vdev_path, error);