From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from magic.merlins.org ([209.81.13.136]:36880 "EHLO mail1.merlins.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755820Ab2FEMXf (ORCPT ); Tue, 5 Jun 2012 08:23:35 -0400 Date: Tue, 5 Jun 2012 04:54:08 -0700 From: Marc MERLIN To: Chris Samuel Cc: linux-btrfs@vger.kernel.org Subject: Re: Recovering a file from a snapshot without duplicating its blocks (--reflink across devs?) Message-ID: <20120605115408.GD7572@merlins.org> References: <20120605030100.GA7572@merlins.org> <4FCD803A.2070906@csamuel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <4FCD803A.2070906@csamuel.org> Sender: linux-btrfs-owner@vger.kernel.org List-ID: On Tue, Jun 05, 2012 at 01:42:50PM +1000, Chris Samuel wrote: > On 05/06/12 13:01, Marc MERLIN wrote: > > > First I though, I sure would be nice if I could take btrfs to reference > > the same blocks from the snapshot to my current image. > > But, --reflink failed across devices nodes, so I was forced to > > copy/duplicate the blocks (36GB). > > Patches for this were posted over a year ago, but it was NAK'd by > Christoph Hellwig. I don't know if it's got any further since then. :-( > > Patch description: > > http://www.spinics.net/lists/linux-btrfs/msg09226.html > > NAK: > > http://www.spinics.net/lists/linux-btrfs/msg09229.html Thanks for that. So, I'm not sure how common my use case is, but obviously for cases were recovering a huge file is important, like disk images, being able to re-link blocks without copying would be fantastic. So here's my vote for that. Thanks, Marc -- "A mouse is a device used to point at the xterm you want to type in" - A.S.R. Microsoft is to operating systems .... .... what McDonalds is to gourmet cooking Home page: http://marc.merlins.org/