From owner-freebsd-questions@FreeBSD.ORG Mon Apr 26 16:23:28 2004 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id B7D4016A4CF for ; Mon, 26 Apr 2004 16:23:28 -0700 (PDT) Received: from mta4.rcsntx.swbell.net (mta4.rcsntx.swbell.net [151.164.30.28]) by mx1.FreeBSD.org (Postfix) with ESMTP id 65A7D43D2D for ; Mon, 26 Apr 2004 16:23:28 -0700 (PDT) (envelope-from kris@obsecurity.org) Received: from obsecurity.dyndns.org (ea71035e6e3c76e613e5e7ee3a352f08@adsl-67-115-73-128.dsl.lsan03.pacbell.net [67.115.73.128])i3QNNLBi011213; Mon, 26 Apr 2004 18:23:21 -0500 (CDT) Received: by obsecurity.dyndns.org (Postfix, from userid 1000) id 5713851FCA; Mon, 26 Apr 2004 16:23:20 -0700 (PDT) Date: Mon, 26 Apr 2004 16:23:20 -0700 From: Kris Kennaway To: Dan Nelson Message-ID: <20040426232319.GA22217@xor.obsecurity.org> References: <20040426182547.GF92049@seekingfire.com> <20040426183717.GF2771@dan.emsphone.com> <20040426184324.GH92049@seekingfire.com> <20040426184710.GA22344@dan.emsphone.com> <20040426224633.GN92049@seekingfire.com> <20040426230855.GB22344@dan.emsphone.com> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="MGYHOYXEY6WxJCY8" Content-Disposition: inline In-Reply-To: <20040426230855.GB22344@dan.emsphone.com> User-Agent: Mutt/1.4.2.1i cc: FreeBSD-Questions Subject: Re: NFS occassionally gives "permission" denied in the middle of a large transfer X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 26 Apr 2004 23:23:29 -0000 --MGYHOYXEY6WxJCY8 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Mon, Apr 26, 2004 at 06:08:56PM -0500, Dan Nelson wrote: > In the last episode (Apr 26), Tillman Hodgson said: > > On Mon, Apr 26, 2004 at 01:47:10PM -0500, Dan Nelson wrote: > > > In the last episode (Apr 26), Tillman Hodgson said: > > > > On Mon, Apr 26, 2004 at 01:37:17PM -0500, Dan Nelson wrote: > > > > > The only time I've seen incorrect permission denied messages is > > > > > when mountd is refreshing the exports list. It's not atomic, > > > > > so there's a small window where the old exports have been > > > > > deleted but the new ones aren't in place yet. > > > >=20 > > > > Is there anything in the default weekly cron jobs that would do > > > > something like that on the file server? > > >=20 > > > I don't think so. Mounting or dismounting local (not NFS) > > > filesystems might do it, but I'm not sure. > >=20 > > Including local filesystems that aren't exported? > >=20 > > If so, that's interesting because I do that in my weekly periodic > > cron job. It's a simple script that umounts a backup partition, > > newfs's it, dumps a local copy of /home over to it, and then > > re-mounts it (for easy user-accessible near-line backup storage that > > doesn't require going to tape for the "real" backup). >=20 > That's probably it, then. /sbin/mount has code that sends SIGHUP to > mountd on any mount operation. Which implies that any manual mount > request, including NFS mounts would, cause the problem. Amd calls the > mount syscall directly, bypassing /sbin/mount. >=20 > Ideally, mountd would be able to compare the current and new export > settings and only update the ones that changed, or have a way to create > a new mountlist and ask the kernel to replace the old one in a single > atomic operation. Very interesting..you might have identified the problem that has plagued me on one of my package build clusters (NFS was unusable because of the frequency of EACCESS errors). A difference between these systems and others is that the NFS server is also used to build packages, and does a lot of unmounting and remounting of local filesystems. I can't test this right now because all of the client machines are dead, but I should be able to soon. Thanks for the insight! Kris --MGYHOYXEY6WxJCY8 Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.4 (FreeBSD) iD8DBQFAjZnnWry0BWjoQKURAnwkAKDVCMJz1ThdxgGOxgvXZQ6ON1iIUQCfYNLE J1+AzRXAz4UtcuzKCRB99bI= =T21D -----END PGP SIGNATURE----- --MGYHOYXEY6WxJCY8--