From owner-freebsd-current@FreeBSD.ORG Thu Sep 8 13:45:18 2011 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id CED44106564A for ; Thu, 8 Sep 2011 13:45:18 +0000 (UTC) (envelope-from rmacklem@uoguelph.ca) Received: from esa-annu.mail.uoguelph.ca (esa-annu.mail.uoguelph.ca [131.104.91.36]) by mx1.freebsd.org (Postfix) with ESMTP id 8D1C38FC0C for ; Thu, 8 Sep 2011 13:45:18 +0000 (UTC) X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: Ap0EAJfFaE6DaFvO/2dsb2JhbABDhFWkIoFwBIEHAg0ZAl+gaI1bkWuBLIQwgREEkzORMg X-IronPort-AV: E=Sophos;i="4.68,350,1312171200"; d="scan'208";a="133686420" Received: from erie.cs.uoguelph.ca (HELO zcs3.mail.uoguelph.ca) ([131.104.91.206]) by esa-annu-pri.mail.uoguelph.ca with ESMTP; 08 Sep 2011 09:45:17 -0400 Received: from zcs3.mail.uoguelph.ca (localhost.localdomain [127.0.0.1]) by zcs3.mail.uoguelph.ca (Postfix) with ESMTP id C86AAB3F1F for ; Thu, 8 Sep 2011 09:45:17 -0400 (EDT) Date: Thu, 8 Sep 2011 09:45:17 -0400 (EDT) From: Rick Macklem To: FreeBSD-Current Message-ID: <2047531658.973519.1315489517809.JavaMail.root@erie.cs.uoguelph.ca> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-Originating-IP: [172.17.91.202] X-Mailer: Zimbra 6.0.10_GA_2692 (ZimbraWebClient - FF3.0 (Win)/6.0.10_GA_2692) Subject: NFS server File Handle changing upon reboot X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 08 Sep 2011 13:45:18 -0000 Hiroki Sato spotted a problem with NFS server file handles (FHs) changing after a server upgrade, because the exported file system type(s) get configured in a different order and, therefore, assigned different vfs_typenum values. A patch has been worked out, after discussion with various folks, that uses a hash function to assign the vfs_typenum values. This fixes the problem, except it has one downside: - The first server boot after the patch has been applied will result in FHs changing and, as such, NFS clients will need to remount after this upgrade. So, finally to why I am posting, which is to ask for opinions on what should be done with this patch? 1 - Ask re@ for permission to commit this to -current for 9.0, so that the FH change happens at the 8.X->9.0 upgrade. (It does seem that if some variant of this should go in, then a major release seems like the correct time to do it?) 2 - Add a loader.conf variable to the patch, which would allow a sysadmin to "flip the switch" when it is convenient for them. (I do have a concern that this might just cause more confusion w.r.t. when/what needs to be done.) 3 - Do #2, for 8.X and make the patch the default for 9.0. 4 - Forget the patch and leave things the way the are now. Please respond asap, since if it is to go in head/9.0, I need to queue up the patch soon. Thanks in advance for any comments, rick ps: This patch was discussed under the subject "fsid change of ZFS?"