From owner-freebsd-fs@FreeBSD.ORG Tue May 12 11:50:32 2015 Return-Path: Delivered-To: freebsd-fs@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 07266C6C; Tue, 12 May 2015 11:50:32 +0000 (UTC) Received: from esa-jnhn.mail.uoguelph.ca (esa-jnhn.mail.uoguelph.ca [131.104.91.44]) by mx1.freebsd.org (Postfix) with ESMTP id B3E541108; Tue, 12 May 2015 11:50:31 +0000 (UTC) X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: A2DDBAA4CE9V/95baINcg2NeAQWDGMFNgViGBQKBVhMBAQEBAQEBgQqEIQEBBCNWGxgCAg0ZAlkGiD8Ns1eSegEBAQEBAQQBAQEBAQEBARqBIYoYhDoXNAeCaIFFBZZbgkaFIz6NLodHI2GBKByBbiIxAQEBAYFBgQEBAQE X-IronPort-AV: E=Sophos;i="5.13,414,1427774400"; d="scan'208";a="210356782" Received: from muskoka.cs.uoguelph.ca (HELO zcs3.mail.uoguelph.ca) ([131.104.91.222]) by esa-jnhn.mail.uoguelph.ca with ESMTP; 12 May 2015 07:50:31 -0400 Received: from zcs3.mail.uoguelph.ca (localhost.localdomain [127.0.0.1]) by zcs3.mail.uoguelph.ca (Postfix) with ESMTP id C59D2B3F45; Tue, 12 May 2015 07:50:29 -0400 (EDT) Date: Tue, 12 May 2015 07:50:29 -0400 (EDT) From: Rick Macklem To: Edward Tomasz =?utf-8?Q?Napiera=C5=82a?= Cc: FreeBSD Filesystems Message-ID: <599930852.36285001.1431431429794.JavaMail.root@uoguelph.ca> In-Reply-To: <20150512074602.GA93864@brick.home> Subject: Re: RFC: should automounted file systems be exportable? MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-Originating-IP: [172.17.95.11] X-Mailer: Zimbra 7.2.6_GA_2926 (ZimbraWebClient - FF3.0 (Win)/7.2.6_GA_2926) X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 12 May 2015 11:50:32 -0000 Edward Napierala wrote: > On 0511T2217, Rick Macklem wrote: > > A recent bug was reported related to mountd and the > > "automounted" flag. > > > > Loosely related to this is the question... > > Should automounted file systems be exportable? > > > > I haven't tested it, but I suspect that it would be > > broken and the NFS server will reply NFSERR_STALE > > after the file system has been dismounted. > > > > So, should I patch mountd so that it won't export > > automounted file systems? > > Exporting an automounted filesystem doesn't seem to make much sense, > I agree, but I'm not sure if adding code to prevent it is such > a good idea. If the user asks for it, by putting it into exports(5), > it's his fault; the only thing this code could add would be a more > friendly error message. > > Well, my thinking is that the recent patch to mountd that avoids doing mount update for non-exported file systems + one that doesn't allow automounted volumes to be exported fixes this bug: http://docs.FreeBSD.org/cgi/mid.cgi?1429477202.29812.38.camel That way, there is no rush w.r.t. how to update the high order bits of flags. (As noted in the comment w.r.t. the review of D2506, I'm not sure if an updated syscall is allowed to be MFC'd.) Since MNT_AUTOMOUNTED is the only high order bit at this time, once it is fixed, no MFC of the more generic fix is needed. Make sense? rick