From owner-freebsd-hackers  Tue Sep 16 00:13:44 1997
Return-Path: <owner-freebsd-hackers>
Received: (from root@localhost)
          by hub.freebsd.org (8.8.7/8.8.7) id AAA21873
          for hackers-outgoing; Tue, 16 Sep 1997 00:13:44 -0700 (PDT)
Received: from cicero.cybercity.dk (cicero.cybercity.dk [195.8.128.13])
          by hub.freebsd.org (8.8.7/8.8.7) with ESMTP id AAA21852
          for <hackers@FreeBSD.ORG>; Tue, 16 Sep 1997 00:13:38 -0700 (PDT)
Received: from schizo.dk.tfs.com (mail.trw.dk [195.8.133.123])
	by cicero.cybercity.dk (8.8.5/8.8.5) with ESMTP id JAA05841;
	Tue, 16 Sep 1997 09:07:46 +0200 (CEST)
Received: from critter.freebsd.dk (critter.dk.tfs.com [140.145.230.252]) by schizo.dk.tfs.com (8.8.7/8.7.3) with ESMTP id JAA07946; Tue, 16 Sep 1997 09:05:00 +0200 (MET DST)
Received: from critter.freebsd.dk (localhost [127.0.0.1])
	by critter.freebsd.dk (8.8.7/8.8.7) with ESMTP id IAA00273;
	Tue, 16 Sep 1997 08:18:25 +0200 (CEST)
To: Eivind Eklund <perhaps@yes.no>
cc: hackers@FreeBSD.ORG
Subject: Re: Pre-conditions (was Re: cvs commit: src/sys/nfs nfs_vnops.c) 
In-reply-to: Your message of "Tue, 16 Sep 1997 01:32:28 +0200."
             <199709152332.BAA25440@bitbox.follo.net> 
Date: Tue, 16 Sep 1997 08:18:25 +0200
Message-ID: <271.874390705@critter.freebsd.dk>
From: Poul-Henning Kamp <phk@critter.freebsd.dk>
Sender: owner-freebsd-hackers@FreeBSD.ORG
X-Loop: FreeBSD.org
Precedence: bulk

In message <199709152332.BAA25440@bitbox.follo.net>, Eivind Eklund writes:
>
>>   Modified files:
>>     sys/nfs              nfs_vnops.c 
>>   Log:
>>   Don't repeat checks done at general level.
>
>On a fairly general level: I'd have changed these to consistency
>checks enclosed in #if DEBUG/#endif, and a panic (lacking a good
>standardized assert facility; assert() is message-less and thus not
>good enough).  I like to make 'each routine its own castle' in
>debugging mode, not trusting ANYTHING that is passed in from anywhere.
>
>How is this for other people?  Is that considered unnecessary
>cluttering of the sources?  Done correctly, I find it a very good form
>of documentation of each functions pre-conditions (and possibly
>post-conditions/invariants, but that is much more clutter).

If circumstances warrant it, ie: you suspect a problem in that area,
by all means go ahead.  If there is no sign of trouble, don't clutter
the sources.

In this particular case we're talkink about checks done against the
vnodes, ie the generic layer, they belong in the generic layer, not
in the individual filesystems.

--
Poul-Henning Kamp             FreeBSD coreteam member
phk@FreeBSD.ORG               "Real hackers run -current on their laptop."