From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751097AbWFQFou (ORCPT ); Sat, 17 Jun 2006 01:44:50 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751244AbWFQFou (ORCPT ); Sat, 17 Jun 2006 01:44:50 -0400 Received: from gprs189-60.eurotel.cz ([160.218.189.60]:30483 "EHLO spitz.ucw.cz") by vger.kernel.org with ESMTP id S1751097AbWFQFot (ORCPT ); Sat, 17 Jun 2006 01:44:49 -0400 Date: Sat, 17 Jun 2006 05:16:58 +0000 From: Pavel Machek To: carl Cc: linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk Subject: Re: [PATCH 1/1] vfs: support for COW files in sys_open Message-ID: <20060617051657.GA7464@ucw.cz> References: <20060609165321.66EEC118601@localhost.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20060609165321.66EEC118601@localhost.localdomain> User-Agent: Mutt/1.5.9i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Hi! > Giving the O_COW flag to open() will return a special error, if > IS_COW(inode) and write permissions are expressed or implied. COW-aware > applications may set this flag and deal with this error according to > some user defined policy. This will not change the semantics of any > existing application or affect any kernel user of open_namei(); nor does > it affect future applications unless they use O_COW. Filesystem level > code is unimplemented except for an ext2 example. Can you give us overview how this is used? COW for ext2 seems nice... Is the plan to allow cp -a --cow linux linux.new ? Pavel -- Thanks for all the (sleeping) penguins.