From owner-freebsd-current@FreeBSD.ORG Mon Mar 9 22:42:09 2009 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 085EE1065677; Mon, 9 Mar 2009 22:42:08 +0000 (UTC) (envelope-from onemda@gmail.com) Received: from mail-ew0-f166.google.com (mail-ew0-f166.google.com [209.85.219.166]) by mx1.freebsd.org (Postfix) with ESMTP id D93B48FC14; Mon, 9 Mar 2009 22:42:07 +0000 (UTC) (envelope-from onemda@gmail.com) Received: by ewy10 with SMTP id 10so1013303ewy.43 for ; Mon, 09 Mar 2009 15:42:07 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:received:in-reply-to:references :date:message-id:subject:from:to:cc:content-type :content-transfer-encoding; bh=kEWk9FYpW9hyJIZpmRZx4R36ISXBT+QSM8AfaXqEw2Q=; b=Q4g2redoly6XBSBWn6FL31oHBi+bhFADDyLSZyL+GKyl3ZWN0GK+ziJeysUJdezrR0 DI8uT6UsgfPBALYQT1MxTLgcL2UwTkIZTH+ZvShUpeRHInCIEwk19YgMiGwW8tF4Wa34 1p2b3Lgrt6niwyJ+pUtOu/SREGEL3/p4cerW0= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; b=Z5OcJzENkAfLY4WYoZ0+o7vfsLWzkZS6ByGcln2BJhGNyv92U6J8/Ys32ctf1UeyT/ jHv4cqLhpGEHQy6wik2jZfTRU+dwnlh0SYGFb5yY+jlUZ8A/3zBs+bWASfkpmpbXr8RV Xqw9bG+JURFEmw9cja6BXX615GCe3HmnXL/xM= MIME-Version: 1.0 Received: by 10.210.112.4 with SMTP id k4mr2863264ebc.81.1236638526584; Mon, 09 Mar 2009 15:42:06 -0700 (PDT) In-Reply-To: <200903091642.25311.jhb@freebsd.org> References: <3a142e750903090615t63a594e8rbadd7f7231049180@mail.gmail.com> <200903091642.25311.jhb@freebsd.org> Date: Mon, 9 Mar 2009 22:42:06 +0000 Message-ID: <3a142e750903091542x7514f74eod294cb15f4ddf1b8@mail.gmail.com> From: "Paul B. Mahol" To: John Baldwin Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: freebsd-current@freebsd.org Subject: Re: nullfs: panic: vrele: negative ref cnt X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 09 Mar 2009 22:42:09 -0000 On 3/9/09, John Baldwin wrote: > On Monday 09 March 2009 9:15:22 am Paul B. Mahol wrote: >> Hi, >> here is part of textdump: >> >> panic(c061db9e,0,c061cee6,88e,4,...) at panic+0x136 >> vrele(c4326d9c,0,c433fb5f,82,c060f3c7,...) at vrele+0x111 >> null_nodeget(c3fd4780,c4326d9c,c3ba8bf4,0,c3ba8be4,...) at >> null_nodeget+0xa0 >> null_bypass(c3ba8be0,c3f35a78,c3ba8c28) at null_bypass+0x141 >> VOP_VPTOCNP_APV(c4340240,c3ba8be0,c061bf01,387,c3cecc00,...) at >> VOP_VPTOCNP_APV+0xb3 > > Try this. null_bypass() can't handle VOP_VPTOCNP because VPTOCNP doesn't > return a vnode that is locked and VREF'd, but just a vnode that is > vhold()'d. > This patch attempts to give nullfs a VOP_VPTONCP() method which remaps the > directory vnode properly on return by locking the directory vnode while > invoking null_nodeget(). It livelocks active vty into [ufs] state. Will try with WITNESS kernel soon. load: 0.01 cmd: sh 1058 [ufs] 0.00u 0.02s 0% 1672k > --- //depot/user/jhb/lock/fs/nullfs/null_vnops.c > +++ /home/jhb/work/p4/lock/fs/nullfs/null_vnops.c > @@ -722,6 +722,34 @@ > return VOP_VPTOFH(lvp, ap->a_fhp); > } > > +static int > +null_vptocnp(struct vop_vptocnp_args *ap) > +{ > + struct vnode *lvp, *dvp; > + int error; > + > + /* > + * We can't use null_bypass() because 'dvp' is not returned > + * locked. It is merely 'vhold()'ed. > + */ > + lvp = NULLVPTOLOWERVP(ap->a_vp); > + error = VOP_VPTOCNP(lvp, &dvp, ap->a_buf, ap->a_buflen); > + if (error) > + return (error); > + > + /* > + * Map 'dvp' to the corresponding null node. We have to lock > + * it before calling null_nodeget(). > + */ > + vn_lock(dvp, LK_SHARED | LK_RETRY); > + error = null_nodeget(ap->a_vp->v_mount, dvp, ap->a_vpp); > + if (error) { > + vrele(dvp); > + vdrop(dvp); > + } > + return (error); > +} > + > /* > * Global vfs data structures > */ > @@ -743,4 +771,5 @@ > .vop_strategy = VOP_EOPNOTSUPP, > .vop_unlock = null_unlock, > .vop_vptofh = null_vptofh, > + .vop_vptocnp = null_vptocnp, > }; > > > -- > John Baldwin >