From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3448AC32771 for ; Thu, 9 Jan 2020 10:34:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0654120678 for ; Thu, 9 Jan 2020 10:34:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729279AbgAIKe2 (ORCPT ); Thu, 9 Jan 2020 05:34:28 -0500 Received: from mail.itouring.de ([188.40.134.68]:44938 "EHLO mail.itouring.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729165AbgAIKe2 (ORCPT ); Thu, 9 Jan 2020 05:34:28 -0500 Received: from tux.applied-asynchrony.com (p5B07E981.dip0.t-ipconnect.de [91.7.233.129]) by mail.itouring.de (Postfix) with ESMTPSA id 2B0FE41669C5; Thu, 9 Jan 2020 11:34:26 +0100 (CET) Received: from [192.168.100.223] (ragnarok.applied-asynchrony.com [192.168.100.223]) by tux.applied-asynchrony.com (Postfix) with ESMTP id C755CF015C3; Thu, 9 Jan 2020 11:34:25 +0100 (CET) Subject: Re: btrfs scrub: cancel + resume not resuming? To: =?UTF-8?Q?Sebastian_D=c3=b6ring?= , linux-btrfs@vger.kernel.org References: From: =?UTF-8?Q?Holger_Hoffst=c3=a4tte?= Organization: Applied Asynchrony, Inc. Message-ID: Date: Thu, 9 Jan 2020 11:34:25 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.9.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org On 1/9/20 11:03 AM, Sebastian Döring wrote: > Maybe I'm doing it entirely wrong, but I can't seem to get 'btrfs > scrub resume' to work properly. During a running scrub the resume > information (like data_bytes_scrubbed:1081454592) gets written to a > file in /var/lib/btrfs, but as soon as the scrub is cancelled all > relevant fields are zeroed. 'btrfs scrub resume' then seems to > re-start from the very beginning. > > This is on linux-5.5-rc5 and btrfs-progs 5.4, but I've been seeing > this for a while now. > > Is this intended/expected behavior? Am I using the btrfs-progs wrong? > How can I interrupt and resume a scrub? Using 5.4.9+ (all of btrfs-5.5) and btrfs-progs 5.4 I just tried and it still works for me (and always has): $btrfs scrub start /mnt/backup scrub started on /mnt/backup, fsid d163af2f-6e03-4972-bfd6-30c68b6ed312 (pid=25633) $btrfs scrub cancel /mnt/backup scrub cancelled $btrfs scrub resume /mnt/backup scrub resumed on /mnt/backup, fsid d163af2f-6e03-4972-bfd6-30c68b6ed312 (pid=25704) ..and it keeps munching away as expected. TBH it's a bit odd that there is no "pause" - I'd expect cancel to be final, but apart from that it seems to work. -h