From owner-freebsd-stable@FreeBSD.ORG Tue Feb 14 02:23:40 2012 Return-Path: Delivered-To: freebsd-stable@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 08BD9106566C; Tue, 14 Feb 2012 02:23:40 +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 9B2248FC08; Tue, 14 Feb 2012 02:23:39 +0000 (UTC) X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: Ap8EAPXEOU+DaFvO/2dsb2JhbAA7CIUQrB2BcgEBAQMBAQEBICsgCxsYAgINGQIpAQkmBggHBAEcBIdbCac/kh6BL4dpgjAVFwUKBwEDAgQHAh0BAwIUBIMeAQYBDQYCg0CBFgSISopAgiiTAg X-IronPort-AV: E=Sophos;i="4.73,414,1325480400"; d="scan'208";a="156285400" Received: from erie.cs.uoguelph.ca (HELO zcs3.mail.uoguelph.ca) ([131.104.91.206]) by esa-annu-pri.mail.uoguelph.ca with ESMTP; 13 Feb 2012 21:23:38 -0500 Received: from zcs3.mail.uoguelph.ca (localhost.localdomain [127.0.0.1]) by zcs3.mail.uoguelph.ca (Postfix) with ESMTP id 82976B3F0E; Mon, 13 Feb 2012 21:23:38 -0500 (EST) Date: Mon, 13 Feb 2012 21:23:38 -0500 (EST) From: Rick Macklem To: Doug Barton Message-ID: <318799457.1320617.1329186218494.JavaMail.root@erie.cs.uoguelph.ca> In-Reply-To: <4F397A70.3080104@FreeBSD.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-Originating-IP: [172.17.91.203] X-Mailer: Zimbra 6.0.10_GA_2692 (ZimbraWebClient - FF3.0 (Linux)/6.0.10_GA_2692) Cc: freebsd-fs@FreeBSD.org, freebsd-stable@FreeBSD.org Subject: Re: Why won't 8.2 umount -f? X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 14 Feb 2012 02:23:40 -0000 Doug Barton wrote: > Is there some magic I'm missing to convince an 8.2 system to umount > -f? > I had an NFS server crash, so I'm trying to get the mounts updated. > All > of the 7.x systems happily did 'umount -f', but the 8.x systems > (mostly > 8.2-pN) are just hanging forever. > > Is this a bug, or is it something I'm missing? > Well, I didn't realize that a 7.n system would "umount -f" an NFS mount when the server was down and there were dirty blocks that needed to be written back, but I don't know. (I seem to recall that someone encouraged me to MFC one of my changes related to this back to stable/7, but I'm not sure if it mattered?) I have pretty well fixed the new client w.r.t. this except for the case where you do a "umount " and that gets hung. Once a non "-f" umount gets hung, there is nothing you can do, because the mount point is locked up, so a subsequent "umount -f" can't get as far as nfs_umount(). My guess is that the old (default for 8.n) client isn't fixed for this. If you "grep MNTK_UNMOUNTF" in the sources, you'll see it used some in the old/regular client, but not as much as the new one. You also need a fairly recent (can't remember if that is in 8.2) version of umount.c, since the code had a "sync();" at the beginning of it that would hang before even getting to the umount(2) syscall. Bottom line, I think the newnfs client (the default for 9.0) can do this, but I'm doubtful the old/reguler one can. (I also wouldn't be surprised if there is still a bug other than the above mentioned one w.r.t. doing a "umount /mnt" and getting that hung before trying "umount -f /mnt". rick > > Doug > > -- > > It's always a long day; 86400 doesn't fit into a short. > > Breadth of IT experience, and depth of knowledge in the DNS. > Yours for the right price. :) http://SupersetSolutions.com/ > > _______________________________________________ > freebsd-stable@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-stable > To unsubscribe, send any mail to > "freebsd-stable-unsubscribe@freebsd.org"