From owner-freebsd-stable@FreeBSD.ORG Sat Jun 12 14:15:57 2010 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 DC417106566C for ; Sat, 12 Jun 2010 14:15:57 +0000 (UTC) (envelope-from kostikbel@gmail.com) Received: from mail.zoral.com.ua (mx0.zoral.com.ua [91.193.166.200]) by mx1.freebsd.org (Postfix) with ESMTP id 4E76D8FC15 for ; Sat, 12 Jun 2010 14:15:56 +0000 (UTC) Received: from deviant.kiev.zoral.com.ua (root@deviant.kiev.zoral.com.ua [10.1.1.148]) by mail.zoral.com.ua (8.14.2/8.14.2) with ESMTP id o5CEFqlm026082 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Sat, 12 Jun 2010 17:15:52 +0300 (EEST) (envelope-from kostikbel@gmail.com) Received: from deviant.kiev.zoral.com.ua (kostik@localhost [127.0.0.1]) by deviant.kiev.zoral.com.ua (8.14.4/8.14.4) with ESMTP id o5CEFqIR076341; Sat, 12 Jun 2010 17:15:52 +0300 (EEST) (envelope-from kostikbel@gmail.com) Received: (from kostik@localhost) by deviant.kiev.zoral.com.ua (8.14.4/8.14.4/Submit) id o5CEFnBe076340; Sat, 12 Jun 2010 17:15:49 +0300 (EEST) (envelope-from kostikbel@gmail.com) X-Authentication-Warning: deviant.kiev.zoral.com.ua: kostik set sender to kostikbel@gmail.com using -f Date: Sat, 12 Jun 2010 17:15:49 +0300 From: Kostik Belousov To: Mikolaj Golub Message-ID: <20100612141549.GM13238@deviant.kiev.zoral.com.ua> References: <20100606144443.GA50876@emmi.physik-pool.tu-berlin.de> <8639wsk4t1.fsf@kopusha.home.net> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="Cqq5NadOW2RfLMJ/" Content-Disposition: inline In-Reply-To: <8639wsk4t1.fsf@kopusha.home.net> User-Agent: Mutt/1.4.2.3i X-Virus-Scanned: clamav-milter 0.95.2 at skuns.kiev.zoral.com.ua X-Virus-Status: Clean X-Spam-Status: No, score=-2.3 required=5.0 tests=ALL_TRUSTED,AWL,BAYES_50, DNS_FROM_OPENWHOIS autolearn=no version=3.2.5 X-Spam-Checker-Version: SpamAssassin 3.2.5 (2008-06-10) on skuns.kiev.zoral.com.ua Cc: Leon Me??ner , freebsd-stable@freebsd.org Subject: Re: freeBSD nullfs together with nfs and "silly rename" 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: Sat, 12 Jun 2010 14:15:57 -0000 --Cqq5NadOW2RfLMJ/ Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Sat, Jun 12, 2010 at 11:56:10AM +0300, Mikolaj Golub wrote: >=20 > On Sun, 6 Jun 2010 16:44:43 +0200 Leon Me??ner wrote: >=20 > LM> Hi, > LM> I hope this is not the wrong list to ask. Didn't get any answers on > LM> -questions. >=20 > LM> When you try to do the following inside a nullfs mounted directory, > LM> where the nullfs origin is itself mounted via nfs you get an error: >=20 > LM> # foo=20 > LM> # tail -f foo&=20 > LM> # rm -f foo=20 > LM> tail: foo: Stale NFS file handle > LM> # fg >=20 > LM> This is really a problem when running services inside jails and using > LM> NFS as storage. As of [2] it looks like this problem is known for a > LM> while. On a normal NFS mount this does not happen as "silly renaming" > LM> [1] works there (producing nasty little .nfsXXXX files). >=20 > nfs_sillyrename() is called when vnode's usecount is more then 1. It is > expected that unlink() syscall increases vnode's usecount in namei() and = if > the file has been already opened usecount will be more then 1. >=20 > But with nullfs layer present the reference counts are held by the upper = node, > not the lower (nfs) one, so when unlink() is called it increases usecount= of > the upper vnode, not nfs vnode and nfs_sillyrename() is never called. >=20 > The strightforward solution looks like to implement null_remove() that wi= ll > increase lower vnode's refcount before calling null_bypass() and then > decrement it after the call. See the attached patch (it works for me on b= oth > 8-STABLE and CURRENT). The upper vnode holds a reference to the lower vnode, as you noted. Now, with your patch, I believe that _all_ calls to the nfs_remove() are happen with refcount > 1. --Cqq5NadOW2RfLMJ/ Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.10 (FreeBSD) iEYEARECAAYFAkwTlpUACgkQC3+MBN1Mb4gkRwCg4QvbVcDxkzdEgeMmtKUpgDP4 F2AAnj+DyLLiPVvIe+7/bjdyKb87oy1f =Jmsd -----END PGP SIGNATURE----- --Cqq5NadOW2RfLMJ/--