From owner-freebsd-arch@FreeBSD.ORG  Sat Nov  3 10:50:45 2007
Return-Path: <owner-freebsd-arch@FreeBSD.ORG>
Delivered-To: freebsd-arch@freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34])
	by hub.freebsd.org (Postfix) with ESMTP id B5DCD16A419;
	Sat,  3 Nov 2007 10:50:45 +0000 (UTC)
	(envelope-from brde@optusnet.com.au)
Received: from fallbackmx02.syd.optusnet.com.au
	(fallbackmx02.syd.optusnet.com.au [211.29.133.72])
	by mx1.freebsd.org (Postfix) with ESMTP id 32E0113C4BB;
	Sat,  3 Nov 2007 10:50:45 +0000 (UTC)
	(envelope-from brde@optusnet.com.au)
Received: from mail06.syd.optusnet.com.au (mail06.syd.optusnet.com.au
	[211.29.132.187])
	by fallbackmx02.syd.optusnet.com.au (8.12.11.20060308/8.12.11) with
	ESMTP id l9VGn8Di030089; Thu, 1 Nov 2007 03:49:08 +1100
Received: from c211-30-219-213.carlnfd3.nsw.optusnet.com.au
	(c211-30-219-213.carlnfd3.nsw.optusnet.com.au [211.30.219.213])
	by mail06.syd.optusnet.com.au (8.13.1/8.13.1) with ESMTP id
	l9VGlrv4006843
	(version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO);
	Thu, 1 Nov 2007 03:48:07 +1100
Date: Thu, 1 Nov 2007 03:48:08 +1100 (EST)
From: Bruce Evans <brde@optusnet.com.au>
X-X-Sender: bde@delplex.bde.org
To: "David O'Brien" <obrien@freebsd.org>
In-Reply-To: <20071026163923.GA95109@dragon.NUXI.org>
Message-ID: <20071101032901.L4676@delplex.bde.org>
References: <20071026163923.GA95109@dragon.NUXI.org>
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed
Cc: freebsd-arch@freebsd.org
Subject: Re: Filesystem INVARIANTS
X-BeenThere: freebsd-arch@freebsd.org
X-Mailman-Version: 2.1.5
Precedence: list
List-Id: Discussion related to FreeBSD architecture <freebsd-arch.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-arch>,
	<mailto:freebsd-arch-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-arch>
List-Post: <mailto:freebsd-arch@freebsd.org>
List-Help: <mailto:freebsd-arch-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-arch>,
	<mailto:freebsd-arch-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Sat, 03 Nov 2007 10:50:45 -0000

On Fri, 26 Oct 2007, David O'Brien wrote:

> Hi folks,
>
> Looking at the code in sys/ufs, I think most of the "DIAGNOSTIC"s should
> really be "INVARIANTS"s.  In fact there are no "INVARIANTS" in the
> filesystem code at this time.

I like not having much clutter from INVARIANTS/KASSERT()s, but having
things under DIAGNOSTICs isn't right.  In fs code, there should be
some unconditional checking that the file system isn't corrupt.  That
doesn't belong under any ifdefs (since the errors it finds are more
like errors in user input than logic errors), and it mostly already
isn't.

> Below is a diff of what I feel should change from "DIAGNOSTIC" to
> "INVARIANTS".  I have not yet had a chance to benchmark the impact of
> this change when only INVARIANTS/INVARIANTS_SUPORT and not DIAGNOSTIC is
> set vs. nothing set.

This changes a few things that are probably only caused by corrupt file
systems, and many things where it isn't clear what the causes might be.
OTOH, there are lots of panics that aren't under any ifdef but are probably
only caused by logic errors.

Bruce