From owner-svn-src-all@freebsd.org  Mon May 16 07:23:25 2016
Return-Path: <owner-svn-src-all@freebsd.org>
Delivered-To: svn-src-all@mailman.ysv.freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org
 [IPv6:2001:1900:2254:206a::19:1])
 by mailman.ysv.freebsd.org (Postfix) with ESMTP id 83F69B3C853;
 Mon, 16 May 2016 07:23:25 +0000 (UTC) (envelope-from avg@FreeBSD.org)
Received: from repo.freebsd.org (repo.freebsd.org
 [IPv6:2610:1c1:1:6068::e6a:0])
 (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits))
 (Client did not present a certificate)
 by mx1.freebsd.org (Postfix) with ESMTPS id 51A8916D0;
 Mon, 16 May 2016 07:23:25 +0000 (UTC) (envelope-from avg@FreeBSD.org)
Received: from repo.freebsd.org ([127.0.1.37])
 by repo.freebsd.org (8.15.2/8.15.2) with ESMTP id u4G7NOVo078896;
 Mon, 16 May 2016 07:23:24 GMT (envelope-from avg@FreeBSD.org)
Received: (from avg@localhost)
 by repo.freebsd.org (8.15.2/8.15.2/Submit) id u4G7NOBU078895;
 Mon, 16 May 2016 07:23:24 GMT (envelope-from avg@FreeBSD.org)
Message-Id: <201605160723.u4G7NOBU078895@repo.freebsd.org>
X-Authentication-Warning: repo.freebsd.org: avg set sender to avg@FreeBSD.org
 using -f
From: Andriy Gapon <avg@FreeBSD.org>
Date: Mon, 16 May 2016 07:23:24 +0000 (UTC)
To: src-committers@freebsd.org, svn-src-all@freebsd.org,
 svn-src-head@freebsd.org
Subject: svn commit: r299913 - head/sys/kern
X-SVN-Group: head
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
X-BeenThere: svn-src-all@freebsd.org
X-Mailman-Version: 2.1.22
Precedence: list
List-Id: "SVN commit messages for the entire src tree \(except for &quot;
 user&quot; and &quot; projects&quot; \)" <svn-src-all.freebsd.org>
List-Unsubscribe: <https://lists.freebsd.org/mailman/options/svn-src-all>,
 <mailto:svn-src-all-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/svn-src-all/>
List-Post: <mailto:svn-src-all@freebsd.org>
List-Help: <mailto:svn-src-all-request@freebsd.org?subject=help>
List-Subscribe: <https://lists.freebsd.org/mailman/listinfo/svn-src-all>,
 <mailto:svn-src-all-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Mon, 16 May 2016 07:23:25 -0000

Author: avg
Date: Mon May 16 07:23:24 2016
New Revision: 299913
URL: https://svnweb.freebsd.org/changeset/base/299913

Log:
  dounmount: do not call mountcheckdirs() for mounts with MNT_IGNORE
  
  This is a bit hackish, but the flag is currently set only for ZFS
  snapshots mounted under .zfs.  mountcheckdirs() can change cdir/rdir
  references to a covered vnode.  But for the said snapshots the covered
  vnode is really ephemeral and it must never be accessed (except
  for a few specific cases).
  
  To do:	consider removing mountcheckdirs() entirely
  
  MFC after:	5 days

Modified:
  head/sys/kern/vfs_mount.c

Modified: head/sys/kern/vfs_mount.c
==============================================================================
--- head/sys/kern/vfs_mount.c	Mon May 16 07:19:33 2016	(r299912)
+++ head/sys/kern/vfs_mount.c	Mon May 16 07:23:24 2016	(r299913)
@@ -1298,7 +1298,8 @@ dounmount(struct mount *mp, int flags, s
 	 */
 	if ((flags & MNT_FORCE) &&
 	    VFS_ROOT(mp, LK_EXCLUSIVE, &fsrootvp) == 0) {
-		if (mp->mnt_vnodecovered != NULL)
+		if (mp->mnt_vnodecovered != NULL &&
+		    (mp->mnt_flag & MNT_IGNORE) == 0)
 			mountcheckdirs(fsrootvp, mp->mnt_vnodecovered);
 		if (fsrootvp == rootvnode) {
 			vrele(rootvnode);
@@ -1319,7 +1320,8 @@ dounmount(struct mount *mp, int flags, s
 	if (error && error != ENXIO) {
 		if ((flags & MNT_FORCE) &&
 		    VFS_ROOT(mp, LK_EXCLUSIVE, &fsrootvp) == 0) {
-			if (mp->mnt_vnodecovered != NULL)
+			if (mp->mnt_vnodecovered != NULL &&
+			    (mp->mnt_flag & MNT_IGNORE) == 0)
 				mountcheckdirs(mp->mnt_vnodecovered, fsrootvp);
 			if (rootvnode == NULL) {
 				rootvnode = fsrootvp;