From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from plane.gmane.org ([80.91.229.3]:46514 "EHLO plane.gmane.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751306AbbDCEhr (ORCPT ); Fri, 3 Apr 2015 00:37:47 -0400 Received: from list by plane.gmane.org with local (Exim 4.69) (envelope-from ) id 1YdtMW-0007yI-6U for linux-btrfs@vger.kernel.org; Fri, 03 Apr 2015 06:37:44 +0200 Received: from ip68-231-22-224.ph.ph.cox.net ([68.231.22.224]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Fri, 03 Apr 2015 06:37:44 +0200 Received: from 1i5t5.duncan by ip68-231-22-224.ph.ph.cox.net with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Fri, 03 Apr 2015 06:37:44 +0200 To: linux-btrfs@vger.kernel.org From: Duncan <1i5t5.duncan@cox.net> Subject: Re: [PATCH v2] btrfs-progs: Doc: Add warning and note on btrfs-convert. Date: Fri, 3 Apr 2015 04:37:38 +0000 (UTC) Message-ID: References: <1427336364-18161-1-git-send-email-quwenruo@cn.fujitsu.com> <20150402151931.GK6821@twin.jikos.cz> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-btrfs-owner@vger.kernel.org List-ID: David Sterba posted on Thu, 02 Apr 2015 17:19:31 +0200 as excerpted: > On Thu, Mar 26, 2015 at 10:19:24AM +0800, Qu Wenruo wrote: >> WARNING: To ensure *btrfs-convert* be able to rollback btrfs, one >> should never execute *btrfs filesystem defragment* or *btrfs balance* >> command on the converted btrfs. > I don't see now why defrag is harmful to rollback. The defragmented data > are written to the "ext free space", ie. where all new modifications get > written. The old data are pinned by the ext2_saved subvolume and can be > restored. Or not? Is defrag ever going to be snapshot-aware-enabled again? If not, then I don't see that (snapshot-unaware) defrag can affect ext2_saved either. But with snapshot-aware-defrag, AFAIK defrag would affect ext2_saved, unless of course it was special-cased... -- Duncan - List replies preferred. No HTML msgs. "Every nonfree program has a lord, a master -- and if you use the program, he is your master." Richard Stallman