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 053C1C00523 for ; Wed, 8 Jan 2020 08:38:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D457D206DA for ; Wed, 8 Jan 2020 08:37:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727421AbgAHIh7 (ORCPT ); Wed, 8 Jan 2020 03:37:59 -0500 Received: from szxga05-in.huawei.com ([45.249.212.191]:8240 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726313AbgAHIh5 (ORCPT ); Wed, 8 Jan 2020 03:37:57 -0500 Received: from DGGEMS404-HUB.china.huawei.com (unknown [172.30.72.59]) by Forcepoint Email with ESMTP id 8F768DF273F778ADA5C4; Wed, 8 Jan 2020 16:37:54 +0800 (CST) Received: from [10.134.22.195] (10.134.22.195) by smtp.huawei.com (10.3.19.204) with Microsoft SMTP Server (TLS) id 14.3.439.0; Wed, 8 Jan 2020 16:37:53 +0800 Subject: Re: [f2fs-dev] Multidevice f2fs mount after disk rearrangement To: Jaegeuk Kim CC: Oleksandr Natalenko , , References: <4c6cf8418236145f7124ac61eb2908ad@natalenko.name> <2c4cafd35d1595a62134203669d7c244@natalenko.name> <20200106184017.GD50058@jaegeuk-macbookpro.roam.corp.google.com> From: Chao Yu Message-ID: <7cf85056-ef3f-b78c-e7cf-8cce5d5ef1ee@huawei.com> Date: Wed, 8 Jan 2020 16:37:52 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <20200106184017.GD50058@jaegeuk-macbookpro.roam.corp.google.com> Content-Type: text/plain; charset="windows-1252" Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.134.22.195] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2020/1/7 2:40, Jaegeuk Kim wrote: > On 01/06, Chao Yu wrote: >> Hello, >> >> Thanks for the report. :) >> >> On 2020/1/5 5:52, Oleksandr Natalenko via Linux-f2fs-devel wrote: >>> Hi. >>> >>> On 04.01.2020 17:29, Oleksandr Natalenko wrote: >>>> I was brave enough to create f2fs filesystem spanning through 2 >>>> physical device using this command: >>>> >>>> # mkfs.f2fs -t 0 /dev/sdc -c /dev/sdd >>>> >>>> It worked fine until I removed /dev/sdb from my system, so f2fs devices >>>> became: >>>> >>>> /dev/sdc -> /dev/sdb >>>> /dev/sdd -> /dev/sdc >>>> >>>> Now, when I try to mount it, I get the following: >>>> >>>> # mount -t f2fs /dev/sdb /mnt/fs >>>> mount: /mnt/fs: mount(2) system call failed: No such file or directory. >>>> >>>> In dmesg: >>>> >>>> [Jan 4 17:25] F2FS-fs (sdb): Mount Device [ 0]: /dev/sdc, >>>> 59063, 0 - 1cd6fff >>>> [ +0,000024] F2FS-fs (sdb): Failed to find devices >>>> >>>> fsck also fails with the following assertion: >>>> >>>> [ASSERT] (init_sb_info: 908) !strcmp((char *)sb->devs[i].path, (char >>>> *)c.devices[i].path) >>>> >>>> Am I doing something obviously stupid, and the device path can be >>>> (somehow) changed so that the mount succeeds, or this is unfixable, >>>> and f2fs relies on persistent device naming? >>>> >>>> Please suggest. >>>> >>>> Thank you. >>> >>> Erm, fine. I studied f2fs-tools code a little bit and discovered that >>> superblock indeed had /dev/sdX paths saved as strings. So I fired up >>> hexedit and just changed the superblock directly on the first device, >>> substituting sdc with sdb and sdd with sdc (I did it twice; I guess >>> there are 2 copies of superblock), and after this the mount worked. >> >> Alright, it works if superblock checksum feature is off... >> >>> >>> Am I really supposed to do this manually ;)? >> >> We'd better add that ability in tune.f2fs. And I guess we need to let >> kernel/fsck to notice that case, and give hint to run tune.f2fs to >> reconfigure primary/secondary/... device paths. > > I'm thinking to add tunesb.f2fs to edit superblock explicitly, since it has > to edit it without getting superblock/checkpoint and other f2fs metadata. > > For example, > # tunesb.f2fs -c /dev/sdb -c /dev/sdc /dev/sda > .. superblock info .. > .. device list .. > .. hot/cold extensions .. > > Will modify the device list, if it's different from parameter. Looks good to me. Thanks, > >> >> Thanks, >> >>> > . >