From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S264505AbUEJFQr (ORCPT ); Mon, 10 May 2004 01:16:47 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S264518AbUEJFQr (ORCPT ); Mon, 10 May 2004 01:16:47 -0400 Received: from ebiederm.dsl.xmission.com ([166.70.28.69]:31381 "EHLO ebiederm.dsl.xmission.com") by vger.kernel.org with ESMTP id S264505AbUEJFQp convert rfc822-to-8bit (ORCPT ); Mon, 10 May 2004 01:16:45 -0400 To: =?iso-8859-1?q?J=F6rn?= Engel Cc: linux-kernel@vger.kernel.org, Jamie Lokier , Pavel Machek , Denis Vlasenko Subject: Re: [ANNOUNCEMENT PATCH COW] proof of concept impementation of cowlinks References: <20040506131731.GA7930@wohnheim.fh-wedel.de> From: ebiederm@xmission.com (Eric W. Biederman) Date: 09 May 2004 23:15:33 -0600 In-Reply-To: <20040506131731.GA7930@wohnheim.fh-wedel.de> Message-ID: User-Agent: Gnus/5.0808 (Gnus v5.8.8) Emacs/21.2 MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org 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. Eric