From owner-freebsd-hackers  Sat Sep  8  0:21:50 2001
Delivered-To: freebsd-hackers@freebsd.org
Received: from mailman.zeta.org.au (mailman.zeta.org.au [203.26.10.16])
	by hub.freebsd.org (Postfix) with ESMTP
	id 080AD37B403; Sat,  8 Sep 2001 00:21:45 -0700 (PDT)
Received: from bde.zeta.org.au (bde.zeta.org.au [203.2.228.102])
	by mailman.zeta.org.au (8.9.3/8.8.7) with ESMTP id RAA05457;
	Sat, 8 Sep 2001 17:21:34 +1000
Date: Sat, 8 Sep 2001 17:20:47 +1000 (EST)
From: Bruce Evans <bde@zeta.org.au>
X-X-Sender:  <bde@alphplex.bde.org>
To: Chris Costello <chris@calldei.com>
Cc: Poul-Henning Kamp <phk@critter.freebsd.dk>,
	Maxim Sobolev <sobomax@FreeBSD.ORG>, Brent Verner <brent@rcfile.org>,
	<current@FreeBSD.ORG>, <hackers@FreeBSD.ORG>
Subject: Re: Junior Kernel Hacker task: improve vnode->v_tag
In-Reply-To: <20010908003843.D548@holly.calldei.com>
Message-ID: <20010908170906.G45139-100000@alphplex.bde.org>
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=US-ASCII
Sender: owner-freebsd-hackers@FreeBSD.ORG
Precedence: bulk
List-ID: <freebsd-hackers.FreeBSD.ORG>
List-Archive: <http://docs.freebsd.org/mail/> (Web Archive)
List-Help: <mailto:majordomo@FreeBSD.ORG?subject=help> (List Instructions)
List-Subscribe: <mailto:majordomo@FreeBSD.ORG?subject=subscribe%20freebsd-hackers>
List-Unsubscribe: <mailto:majordomo@FreeBSD.ORG?subject=unsubscribe%20freebsd-hackers>
X-Loop: FreeBSD.ORG

On Sat, 8 Sep 2001, Chris Costello wrote:

> On Saturday, September 08, 2001, Poul-Henning Kamp wrote:
> > No actually not, I want something short and predictable like
> > "VT_CODA".
>
>    How about my second suggestion: making v_tag point to
> mp->mnt_stat.f_fstypename, or a copy thereof?

Good, but I as far as I understand this, the only legitimate point of
v_tag is to tell applications like fstat(1) the type of the vnode.
fstat can find chase the kernel pointers in
vp->v_mount->mnt_stat->f_fstypename almost as (un)easily as it could
chase vp->v_tag if v_tag is a pointer.  Copying the string would give
ugly bloat, but would not be all that much worse than the bloat for a
pointer on alphas (the contents of the string "VT_CODA" takes the same
space as a pointer on alphas).

Bruce


To Unsubscribe: send mail to majordomo@FreeBSD.org
with "unsubscribe freebsd-hackers" in the body of the message