From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262153AbTKTVfg (ORCPT ); Thu, 20 Nov 2003 16:35:36 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262491AbTKTVfg (ORCPT ); Thu, 20 Nov 2003 16:35:36 -0500 Received: from kinesis.swishmail.com ([209.10.110.86]:64523 "HELO kinesis.swishmail.com") by vger.kernel.org with SMTP id S262153AbTKTVff (ORCPT ); Thu, 20 Nov 2003 16:35:35 -0500 Message-ID: <3FBD328C.1070607@techsource.com> Date: Thu, 20 Nov 2003 16:30:52 -0500 From: Timothy Miller User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.0.1) Gecko/20020823 Netscape/7.0 X-Accept-Language: en-us, en MIME-Version: 1.0 To: Andreas Dilger CC: Justin Cormack , Jesse Pollard , linux-kernel mailing list Subject: Re: OT: why no file copy() libc/syscall ?? References: <1068512710.722.161.camel@cube> <03111209360001.11900@tabby> <20031120172143.GA7390@deneb.enyo.de> <03112013081700.27566@tabby> <1069357453.26642.93.camel@lotte.street-vision.com> <3FBD27A0.50803@techsource.com> <20031120140739.I20568@schatzie.adilger.int> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Andreas Dilger wrote: > On Nov 20, 2003 15:44 -0500, Timothy Miller wrote: > >>This could be a problem if COW causes you to run out of space when >>writing to the file. > > > Not much different than running out of space copying a file. It is, though. If you run out of space copying a file, you know it when you're copying. Applications don't usually expect to get out-of-space errors while overwriting something in the middle of a file. In effect, your free space and your used space add up to greater than the capacity of the disk. An application that checks for free space before doing something would be fooled into thinking there is more free space than there really is. How can an application find out in advance that a file that it's about to modify (without appending anything to the end) is going to need more disk space?