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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 82A40C4321E for ; Sat, 26 Nov 2022 03:21:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230029AbiKZDVC (ORCPT ); Fri, 25 Nov 2022 22:21:02 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60504 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229733AbiKZDVB (ORCPT ); Fri, 25 Nov 2022 22:21:01 -0500 Received: from out30-130.freemail.mail.aliyun.com (out30-130.freemail.mail.aliyun.com [115.124.30.130]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D862159FD7 for ; Fri, 25 Nov 2022 19:20:53 -0800 (PST) X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R161e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=ay29a033018046049;MF=jefflexu@linux.alibaba.com;NM=1;PH=DS;RN=8;SR=0;TI=SMTPD_---0VVhOwfb_1669432849; Received: from 30.15.198.69(mailfrom:jefflexu@linux.alibaba.com fp:SMTPD_---0VVhOwfb_1669432849) by smtp.aliyun-inc.com; Sat, 26 Nov 2022 11:20:50 +0800 Message-ID: Date: Sat, 26 Nov 2022 11:20:49 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:102.0) Gecko/20100101 Thunderbird/102.4.0 Subject: Re: [PATCH v2] erofs: check the uniqueness of fsid in shared domain in advance Content-Language: en-US To: Hou Tao , linux-erofs@lists.ozlabs.org Cc: linux-kernel@vger.kernel.org, Gao Xiang , Chao Yu , Yue Hu , Jia Zhu , houtao1@huawei.com References: <20221125110822.3812942-1-houtao@huaweicloud.com> From: Jingbo Xu In-Reply-To: <20221125110822.3812942-1-houtao@huaweicloud.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Tao, Thanks for catching this! On 11/25/22 7:08 PM, Hou Tao wrote: > From: Hou Tao > > When shared domain is enabled, doing mount twice with the same fsid and > domain_id will trigger sysfs warning as shown below: > > sysfs: cannot create duplicate filename '/fs/erofs/d0,meta.bin' > CPU: 15 PID: 1051 Comm: mount Not tainted 6.1.0-rc6+ #1 > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996) > Call Trace: > > dump_stack_lvl+0x38/0x49 > dump_stack+0x10/0x12 > sysfs_warn_dup.cold+0x17/0x27 > sysfs_create_dir_ns+0xb8/0xd0 > kobject_add_internal+0xb1/0x240 > kobject_init_and_add+0x71/0xa0 > erofs_register_sysfs+0x89/0x110 > erofs_fc_fill_super+0x98c/0xaf0 > vfs_get_super+0x7d/0x100 > get_tree_nodev+0x16/0x20 > erofs_fc_get_tree+0x20/0x30 > vfs_get_tree+0x24/0xb0 > path_mount+0x2fa/0xa90 > do_mount+0x7c/0xa0 > __x64_sys_mount+0x8b/0xe0 > do_syscall_64+0x30/0x60 > entry_SYSCALL_64_after_hwframe+0x46/0xb0 > > The reason is erofs_fscache_register_cookie() doesn't guarantee the primary > data blob (aka fsid) is unique in the shared domain and > erofs_register_sysfs() invoked by the second mount will fail due to the > duplicated fsid in the shared domain and report warning. > > It would be better to check the uniqueness of fsid before doing > erofs_register_sysfs(), so adding a new flags parameter for > erofs_fscache_register_cookie() and doing the uniqueness check if > EROFS_REG_COOKIE_NEED_NOEXIST is enabled. > > After the patch, the error in dmesg for the duplicated mount would be: > > erofs: ...: erofs_domain_register_cookie: XX already exists in domain YY > > Reviewed-by: Jia Zhu > Signed-off-by: Hou Tao LGTM. Reviewed-by: Jingbo Xu -- Thanks, Jingbo