From owner-freebsd-current@FreeBSD.ORG Mon May 12 13:17:11 2003 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id C73B437B401 for ; Mon, 12 May 2003 13:17:11 -0700 (PDT) Received: from mx0.freebsd-services.com (survey.codeburst.net [195.149.39.161]) by mx1.FreeBSD.org (Postfix) with ESMTP id E209D43F85 for ; Mon, 12 May 2003 13:17:10 -0700 (PDT) (envelope-from paul@freebsd-services.com) Received: from [192.168.7.2] (freebsd.gotadsl.co.uk [81.6.249.198]) by mx0.freebsd-services.com (Postfix) with ESMTP id 5B84F1B211; Mon, 12 May 2003 21:17:09 +0100 (BST) From: Paul Richards To: Kirk McKusick In-Reply-To: <200305121933.h4CJXHTh037943@beastie.mckusick.com> References: <200305121933.h4CJXHTh037943@beastie.mckusick.com> Content-Type: text/plain Organization: Message-Id: <1052770339.667.1.camel@cf.freebsd-services.com> Mime-Version: 1.0 X-Mailer: Ximian Evolution 1.2.4 Date: 12 May 2003 21:12:21 +0100 Content-Transfer-Encoding: 7bit cc: Julian Elischer cc: freebsd-current@freebsd.org Subject: Re: large ufs2 partitions and 'df' X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 12 May 2003 20:17:12 -0000 On Mon, 2003-05-12 at 20:33, Kirk McKusick wrote: > Date: Mon, 12 May 2003 07:53:49 -0700 > From: Terry Lambert > To: Kirk McKusick > CC: Julian Elischer , freebsd-current@freebsd.org > Subject: Re: large ufs2 partitions and 'df' > X-ASK-Info: Whitelist match > > Kirk McKusick wrote: > > Julian Elisher wrote: > > > I think that swithing to a new syscall with a fixed structure > > > and using the rules you mention above to populate the structure in > > > an ostatfs call might be the best answer. > > > Old binaries probably only need to know that there is > X blocks > > > free and not necessarily the correct number. > > > New binaries can use the new syscall. > > > > So right you are. It would be possible to get the space by nibbling > > a bit more space from MNAMELEN, but at some point we need to just bite > > the bullet and define a new structure. I am leaning towards believing > > that time is now. If we do define a new structure, I would like to > > clean up the existing one a bit. I would propose this: > > If you're going to change the structure, please put a version > number as the first field, so that it's never a problem again. > > Also, put a spare field on the end (64 bits) to allow for > future expansion that maintains binary compatability (by way > of choice about what to copy in). > > -- Terry > > There are already ten spare 64-bit numbers in the middle of the > proposed new structure. They are there where they are guaranteed > to be 64-bit aligned rather than at the end where there is danger > of them being aligned differently on different architectures since > they follow character arrays. A version number would be a good idea though so apps have some chance of knowing what fields are being used in the future. -- Paul Richards