From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S264842AbUEJQA3 (ORCPT ); Mon, 10 May 2004 12:00:29 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S264840AbUEJQA3 (ORCPT ); Mon, 10 May 2004 12:00:29 -0400 Received: from mail.fh-wedel.de ([213.39.232.194]:41108 "EHLO mail.fh-wedel.de") by vger.kernel.org with ESMTP id S264842AbUEJQAL (ORCPT ); Mon, 10 May 2004 12:00:11 -0400 Date: Mon, 10 May 2004 17:59:58 +0200 From: =?iso-8859-1?Q?J=F6rn?= Engel To: "Eric W. Biederman" Cc: linux-kernel@vger.kernel.org, Jamie Lokier , Pavel Machek , Denis Vlasenko Subject: Re: [ANNOUNCEMENT PATCH COW] proof of concept impementation of cowlinks Message-ID: <20040510155958.GD16182@wohnheim.fh-wedel.de> References: <20040506131731.GA7930@wohnheim.fh-wedel.de> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/1.3.28i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Sun, 9 May 2004 23:15:33 -0600, Eric W. Biederman wrote: > Jörn Engel writes: > > 3 copyfile - new copyfile() system call > > http://wohnheim.fh-wedel.de/~joern/cowlink/ > > Question about sys_copyfile. > > Is the intention that a new file with completely new permissions > be created? > > Some people have wanted a copyfile that copies all of the extra > metadata user/group/acls. > > I currently see technical merit in both approaches. > > Looking at the CIFS information it appears that the CopyFILE RPC > copies the permissions. It is not at all clear about that, and > the fact it appears to copy permissions may simply be a specification > bug. Given that FAT does not really have permissions, let alone > extended attributes it would be an easy mistake to make. > > In the general case you cannot copy permissions from one file to > another, either you don't have those permissions yourself or the > target file system may not support them all. Not copying > permissions leads to a simpler implementation with the burden > of the work left to user space. What is not done is a loop through > the extended attributes. Unless someone finds a good reason to change this, I prefer to create new permissions and not copy the acl's. That way, I can also copyfile() a file belonging to someone else, as long as I have read access to it. Jörn -- Don't worry about people stealing your ideas. If your ideas are any good, you'll have to ram them down people's throats. -- Howard Aiken quoted by Ken Iverson quoted by Jim Horning quoted by Raph Levien, 1979