From owner-freebsd-hackers@FreeBSD.ORG Thu Aug 5 14:58:22 2004 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 9887916A4D0 for ; Thu, 5 Aug 2004 14:58:22 +0000 (GMT) Received: from skippyii.compar.com (cistore.compar.com [216.208.38.130]) by mx1.FreeBSD.org (Postfix) with ESMTP id 3094943D1F for ; Thu, 5 Aug 2004 14:58:22 +0000 (GMT) (envelope-from matt@gsicomp.on.ca) Received: from hermes (CPE00062566c7bb-CM000039c69a66.cpe.net.cable.rogers.com [69.193.82.185])i75F373J005768; Thu, 5 Aug 2004 11:03:09 -0400 (EDT) (envelope-from matt@gsicomp.on.ca) Message-ID: <001b01c47afc$3c125c40$1200a8c0@gsicomp.on.ca> From: "Matt Emmerton" To: , References: <20040804144019.83129.qmail@web51805.mail.yahoo.com> <200408051719.44705.ilker.ozupak@emu.edu.tr> Date: Thu, 5 Aug 2004 10:55:19 -0400 MIME-Version: 1.0 Content-Type: text/plain; charset="big5" Content-Transfer-Encoding: 7bit X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2800.1437 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1441 Subject: Re: Mount name length limit (MNAMELEN) X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 05 Aug 2004 14:58:22 -0000 > On Wednesday 04 August 2004 17:40, Patrick Dung wrote: > > Hi > > > > It seems that the constant is in /usr/sys/sys/mount.h. > > The limit is already there since the initial import in > > 1995. (From 4.4BSD?) > > I want to know what is the root cause preventing a > > larger value. > > > > PS: I have found some interesting links about > > MNAMELEN: > > > > http://leaf.dragonflybsd.org/mailarchive/kernel/2003-08/msg00194.html > > > > http://www.secnetix.de/~olli/FreeBSD/mnamelen.hawk I recall bringing this up on the FreeBSD lists a while ago (1-2 years?) and IIRC, the reason this is tough to change is that we use this constant in a lot of internal structures, and changing the constant will change the structure sizes which will break a lot of things. >From what I've seen in the Linux code, they never store a "char blah[MNAMELEN]" in their structures, but rather, a pointer to that data element (in the name cache, I think). Thus, they are free to change the size of the element without affecting the majority of structures that use it. -- Matt Emmerton