From owner-freebsd-hackers@FreeBSD.ORG Fri Feb 16 14:37:13 2007 Return-Path: X-Original-To: hackers@freebsd.org Delivered-To: freebsd-hackers@FreeBSD.ORG Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id 3B95916A402; Fri, 16 Feb 2007 14:37:13 +0000 (UTC) (envelope-from kostikbel@gmail.com) Received: from relay01.kiev.sovam.com (relay01.kiev.sovam.com [62.64.120.200]) by mx1.freebsd.org (Postfix) with ESMTP id BC70713C467; Fri, 16 Feb 2007 14:37:12 +0000 (UTC) (envelope-from kostikbel@gmail.com) Received: from [212.82.216.227] (helo=fw.zoral.com.ua) by relay01.kiev.sovam.com with esmtps (TLSv1:AES256-SHA:256) (Exim 4.60) (envelope-from ) id 1HI4Ct-0004Fy-5m; Fri, 16 Feb 2007 16:37:11 +0200 Received: from deviant.kiev.zoral.com.ua (root@deviant.kiev.zoral.com.ua [10.1.1.148]) by fw.zoral.com.ua (8.13.4/8.13.4) with ESMTP id l1GEauKq043680 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Fri, 16 Feb 2007 16:36:56 +0200 (EET) (envelope-from kostikbel@gmail.com) Received: from deviant.kiev.zoral.com.ua (kostik@localhost [127.0.0.1]) by deviant.kiev.zoral.com.ua (8.13.8/8.13.8) with ESMTP id l1GEauVl019393; Fri, 16 Feb 2007 16:36:56 +0200 (EET) (envelope-from kostikbel@gmail.com) Received: (from kostik@localhost) by deviant.kiev.zoral.com.ua (8.13.8/8.13.8/Submit) id l1GEauSJ019392; Fri, 16 Feb 2007 16:36:56 +0200 (EET) (envelope-from kostikbel@gmail.com) X-Authentication-Warning: deviant.kiev.zoral.com.ua: kostik set sender to kostikbel@gmail.com using -f Date: Fri, 16 Feb 2007 16:36:56 +0200 From: Kostik Belousov To: Robert Watson Message-ID: <20070216143656.GM39168@deviant.kiev.zoral.com.ua> References: <20070204023711.GA3393@genius.tao.org.uk> <20070215135750.GR64768@obiwan.tataz.chchile.org> <20070215152259.GA2950@genius.tao.org.uk> <20070215153135.GI39168@deviant.kiev.zoral.com.ua> <20070216125007.D38234@fledge.watson.org> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="NZtAI5QFBF0GmLcW" Content-Disposition: inline In-Reply-To: <20070216125007.D38234@fledge.watson.org> User-Agent: Mutt/1.4.2.2i X-Virus-Scanned: ClamAV version 0.88.7, clamav-milter version 0.88.7 on fw.zoral.com.ua X-Virus-Status: Clean X-Scanner-Signature: b11a0dd960b728cbee92fea3b4ac1d10 X-DrWeb-checked: yes X-SpamTest-Envelope-From: kostikbel@gmail.com X-SpamTest-Group-ID: 00000000 X-SpamTest-Info: Profiles 782 [Feb 16 2007] X-SpamTest-Info: helo_type=3 X-SpamTest-Info: {received from trusted relay: not dialup} X-SpamTest-Method: none X-SpamTest-Method: Local Lists X-SpamTest-Rate: 0 X-SpamTest-Status: Not detected X-SpamTest-Status-Extended: not_detected X-SpamTest-Version: SMTP-Filter Version 3.0.0 [0255], KAS30/Release Cc: Josef Karthauser , hackers@freebsd.org, Jeremie Le Hen , fs@freebsd.org Subject: Re: nullfs and named pipes. X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 16 Feb 2007 14:37:13 -0000 --NZtAI5QFBF0GmLcW Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Fri, Feb 16, 2007 at 12:54:39PM +0000, Robert Watson wrote: >=20 > On Thu, 15 Feb 2007, Kostik Belousov wrote: >=20 > >On Thu, Feb 15, 2007 at 03:22:59PM +0000, Josef Karthauser wrote: > >>On Thu, Feb 15, 2007 at 02:57:50PM +0100, Jeremie Le Hen wrote: > >>> > >>>Note that all processes within a jail can only intefere with processes= =20 > >>>from another jail or host as if they were on different machines. This= =20 > >>>means they can communicate through PF_INET for instance but not PF_LOC= AL. > >> > >>You might think so! However that's not what's going on here. > >> > >>The named pipe/nullfs issue is nothing to do with jails. It's just tha= t=20 > >>nullfs is broken with respect to named pipes as I've previously reporte= d.=20 > >>However with this patch: > >> > >> cvs diff: Diffing . > >> Index: null_subr.c > >> =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D > >> RCS file: /home/ncvs/src/sys/fs/nullfs/null_subr.c,v > >> retrieving revision 1.48.2.1 > >> diff -u -r1.48.2.1 null_subr.c > >> --- null_subr.c 13 Mar 2006 03:05:17 -0000 1.48.2.1 > >> +++ null_subr.c 14 Feb 2007 00:02:28 -0000 > >> @@ -235,6 +235,8 @@ > >> xp->null_vnode =3D vp; > >> xp->null_lowervp =3D lowervp; > >> vp->v_type =3D lowervp->v_type; > >> + if (vp->v_type =3D=3D VSOCK || vp->v_type =3D=3D VFIFO) > >> + vp->v_un =3D lowervp->v_un; > > > >I'm wondering is some reference counting needed there ? >=20 > Yes, I find this a bit worrying also, but I don't know enough about how= =20 > nullfs works to reason about it. What happens when a vnode in the bottom= =20 > layer has its on-disk reference count drop to zero -- is the vnode in the= =20 > top layer invalidated somehow? Vnode reclamation from lower layer cannot do anithing for corresponding nul= lfs vnode, but that vnode has reference from nullfs vnode. On the other hand, can forced unmount proceed for lower layer ? --NZtAI5QFBF0GmLcW Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.6 (FreeBSD) iD8DBQFF1cGHC3+MBN1Mb4gRAmbnAJ4rZL3YjmoJjaBDku4KTaq8fBPSbQCcDAsr S6l/UoJLOLDXyGST6j7MVjM= =1gZf -----END PGP SIGNATURE----- --NZtAI5QFBF0GmLcW--