From owner-cvs-src@FreeBSD.ORG  Thu Apr 14 01:38:42 2005
Return-Path: <owner-cvs-src@FreeBSD.ORG>
Delivered-To: cvs-src@freebsd.org
Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125])
	by hub.freebsd.org (Postfix) with ESMTP
	id 826CD16A4CE; Thu, 14 Apr 2005 01:38:42 +0000 (GMT)
Received: from elvis.mu.org (elvis.mu.org [192.203.228.196])
	by mx1.FreeBSD.org (Postfix) with ESMTP
	id 5571843D58; Thu, 14 Apr 2005 01:38:42 +0000 (GMT)
	(envelope-from bright@elvis.mu.org)
Received: by elvis.mu.org (Postfix, from userid 1192)
	id 4A2475CA4E; Wed, 13 Apr 2005 18:38:42 -0700 (PDT)
Date: Wed, 13 Apr 2005 18:38:42 -0700
From: Alfred Perlstein <alfred@freebsd.org>
To: Jeff Roberson <jroberson@chesapeake.net>
Message-ID: <20050414013842.GH60345@elvis.mu.org>
References: <200504131059.j3DAxAUf039007@repoman.freebsd.org>
	<20050413195741.GE60345@elvis.mu.org>
	<20050413182958.L28571@mail.chesapeake.net>
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20050413182958.L28571@mail.chesapeake.net>
User-Agent: Mutt/1.4.2.1i
cc: cvs-src@FreeBSD.org
cc: Jeff Roberson <jeff@FreeBSD.org>
cc: src-committers@FreeBSD.org
cc: cvs-all@FreeBSD.org
Subject: Re: cvs commit: src/sys/coda coda_vnops.c src/sys/compat/linux
	linux_getcwd.c src/sys/fs/devfs devfs_vnops.c src/sys/fs/hpfs
	hpfs_vnops.c src/sys/fs/msdosfs msdosfs_lookup.c src/sys/fs/nwfs
	nwfs_vnops
X-BeenThere: cvs-src@freebsd.org
X-Mailman-Version: 2.1.1
Precedence: list
List-Id: CVS commit messages for the src tree <cvs-src.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/cvs-src>,
	<mailto:cvs-src-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/cvs-src>
List-Post: <mailto:cvs-src@freebsd.org>
List-Help: <mailto:cvs-src-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/cvs-src>,
	<mailto:cvs-src-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Thu, 14 Apr 2005 01:38:42 -0000

* Jeff Roberson <jroberson@chesapeake.net> [050413 15:31] wrote:
> On Wed, 13 Apr 2005, Alfred Perlstein wrote:
> 
> > * Jeff Roberson <jeff@FreeBSD.org> [050413 03:59] wrote:
> > > jeff        2005-04-13 10:59:10 UTC
> > >
> > >   FreeBSD src repository
> > >
> > >   Modified files:
> > >     sys/coda             coda_vnops.c
> > >     sys/compat/linux     linux_getcwd.c
> > >   Log:
> > >    - Change all filesystems and vfs_cache to relock the dvp once the child is
> > >      locked in the ISDOTDOT case.  Se vfs_lookup.c r1.79 for details.
> >
> > Sorry to bumble into your way, but can you explain this?  I thought
> > the lock order was always dvp->vp, doing a vp->dvp lock is a reversal
> > and can cause deadlock.  I guess I'm missing something, can you explain
> > please?
> 
> For ISDOTDOT dvp is really the child of vp.  For example
> 
> a/b/c
> 
> b/.. is a, and a must be locked before b.  So b must be unlocked before we
> can lock ..(a), and then b must be locked again.

Ok thanks!

-- 
- Alfred Perlstein
- email: bright@mu.org cell: 408-480-4684