From mboxrd@z Thu Jan 1 00:00:00 1970 From: Joel Becker Subject: Re: copy-on-write files Date: Mon, 11 May 2009 10:53:27 -0700 Message-ID: <20090511175327.GA30293@mail.oracle.com> References: <524f69650905111008p4b3d9256qdd0a86c08db31b37@mail.gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: samba-technical , linux-fsdevel To: Steve French Return-path: Received: from acsinet12.oracle.com ([141.146.126.234]:44528 "EHLO acsinet12.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753601AbZEKRzg (ORCPT ); Mon, 11 May 2009 13:55:36 -0400 Content-Disposition: inline In-Reply-To: <524f69650905111008p4b3d9256qdd0a86c08db31b37@mail.gmail.com> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On Mon, May 11, 2009 at 12:08:17PM -0500, Steve French wrote: > Joel, > Looking at your documentation for the new "reflink" syscall (to create > copy-on-write files): > http://git.kernel.org/?p=linux/kernel/git/jlbec/ocfs2.git;a=blob;f=Documentation/filesystems/reflink.txt;h=58a6b3879114c0cb591fb736152b30291037edd2;hb=c04db1c934e67337318b177688c0b882297fdd66 > > Have you looked at whether this is close enough to the existing (e.g. > Windows NTFS) copy-on-write syntax/feature so that we could use it > under Samba (and on the client side from cifs and in the future smb2). > Windows added copy-on-write about 9 or 10 years ago and uses it > extensively. although I have not researched enough to see what > creating these would look like over the network. I didn't know NTFS had it, I don't know the syntax and behavior, and I wonder where Windows uses it (I haven't encountered it on Windows machines, but perhaps it is hidden). Do you have a pointer to any non-encumbered documentation about the feature? Joel -- "If the human brain were so simple we could understand it, we would be so simple that we could not." - W. A. Clouston Joel Becker Principal Software Developer Oracle E-mail: joel.becker@oracle.com Phone: (650) 506-8127