From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S264796AbUEKP6o (ORCPT ); Tue, 11 May 2004 11:58:44 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S264798AbUEKP6o (ORCPT ); Tue, 11 May 2004 11:58:44 -0400 Received: from mail.fh-wedel.de ([213.39.232.194]:63143 "EHLO mail.fh-wedel.de") by vger.kernel.org with ESMTP id S264796AbUEKP6m (ORCPT ); Tue, 11 May 2004 11:58:42 -0400 Date: Tue, 11 May 2004 17:58:27 +0200 From: =?iso-8859-1?Q?J=F6rn?= Engel To: Steve French Cc: Jan Harkes , linux-kernel@vger.kernel.org Subject: Re: [ANNOUNCEMENT PATCH COW] proof of concept impementation of cowlinks Message-ID: <20040511155827.GA11204@wohnheim.fh-wedel.de> References: <20040506131731.GA7930@wohnheim.fh-wedel.de> <20040508224835.GE29255@atrey.karlin.mff.cuni.cz> <20040510155359.GB16182@wohnheim.fh-wedel.de> <20040510192601.GA11362@delft.aura.cs.cmu.edu> <20040511100232.GA31673@wohnheim.fh-wedel.de> <1084290049.5135.11.camel@stevef95.austin.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <1084290049.5135.11.camel@stevef95.austin.ibm.com> User-Agent: Mutt/1.3.28i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 11 May 2004 10:40:49 -0500, Steve French wrote: > > It would not be helpful to take a userspace request to perform a file > (or directory) copy operation and break it into open/sendfile/close by > passing file handles to the network filesystem and have this work for > SMB/CIFS - there is no equivalent network protocol operation. It also > makes the operation much, much harder to make atomic (since two systems > are involved) and makes error handling and recovery for network > filesystems much harder since inconsistent client and server state have > to be considered if the copy operation is broken into pieces on the > clien (it is also slower - a single copy operation on the network is the > absolute optimal case - minimizes the expensive network latency - the > roundtrip delay - open/sendfile/close sends at a minimum three times as > many but likely four with an extra lookup or two) > > Currently copy file (or copy directory for that matter) as both speced > (and is implemented in various servers) in the SMB/CIFS network > filesystem protocol takes in effect four parameters (there is no handle > based file copy): > > a source pathname, and source export (actually SMB tree identifier for > a share, but in effect the same thing) > a target pathname, and target export (actually SMB tree identifier for a > share, but in effect the same thing) > And the shares (exports) referenced have to be on the same server Or in short, copyfile makes sense for smbfs/cifs. The question whether my hack can be cleaned up enough to get past Al Viro is still open, though. :) Jörn -- Homo Sapiens is a goal, not a description. -- unknown