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 D0FE4C6FA81 for ; Fri, 2 Sep 2022 06:10:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235376AbiIBGKJ (ORCPT ); Fri, 2 Sep 2022 02:10:09 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46644 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235422AbiIBGKG (ORCPT ); Fri, 2 Sep 2022 02:10:06 -0400 Received: from dggsgout11.his.huawei.com (dggsgout11.his.huawei.com [45.249.212.51]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id F2DCF1208C; Thu, 1 Sep 2022 23:10:02 -0700 (PDT) Received: from mail02.huawei.com (unknown [172.30.67.143]) by dggsgout11.his.huawei.com (SkyGuard) with ESMTP id 4MJnXc3GHmzl0wj; Fri, 2 Sep 2022 14:08:32 +0800 (CST) Received: from [10.174.176.73] (unknown [10.174.176.73]) by APP2 (Coremail) with SMTP id Syh0CgD3SXM2nhFjYkwIAQ--.59249S3; Fri, 02 Sep 2022 14:09:59 +0800 (CST) Subject: Re: [PATCH] fs: fix possible inconsistent mount device To: Christoph Hellwig , Yu Kuai Cc: viro@zeniv.linux.org.uk, linux-fsdevel@vger.kernel.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, yi.zhang@huawei.com, "yukuai (C)" References: <20220813060848.1457301-1-yukuai1@huaweicloud.com> <230cf303-b241-957d-f5aa-5d367eddeb3f@huaweicloud.com> From: Yu Kuai Message-ID: <79effa0e-7ffe-4275-cf36-01fd3d0615b9@huaweicloud.com> Date: Fri, 2 Sep 2022 14:09:58 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=gbk; format=flowed Content-Transfer-Encoding: 8bit X-CM-TRANSID: Syh0CgD3SXM2nhFjYkwIAQ--.59249S3 X-Coremail-Antispam: 1UD129KBjvdXoWrZw17JryUZrykCry5GF1UGFg_yoW3ArXE9a yfJ39rJ3ZrGF1F9w42kFsrtas7Jry7Zr1UAa1fXrZ7Was5ZrZ5uFWqk3yfZr4Syr98ur1Y 9r4vqrZFqFZ3ujkaLaAFLSUrUUUUUb8apTn2vfkv8UJUUUU8Yxn0WfASr-VFAUDa7-sFnT 9fnUUIcSsGvfJTRUUUb4kFF20E14v26r4j6ryUM7CY07I20VC2zVCF04k26cxKx2IYs7xG 6rWj6s0DM7CIcVAFz4kK6r1j6r18M28lY4IEw2IIxxk0rwA2F7IY1VAKz4vEj48ve4kI8w A2z4x0Y4vE2Ix0cI8IcVAFwI0_Ar0_tr1l84ACjcxK6xIIjxv20xvEc7CjxVAFwI0_Gr1j 6F4UJwA2z4x0Y4vEx4A2jsIE14v26rxl6s0DM28EF7xvwVC2z280aVCY1x0267AKxVW0oV Cq3wAS0I0E0xvYzxvE52x082IY62kv0487Mc02F40EFcxC0VAKzVAqx4xG6I80ewAv7VC0 I7IYx2IY67AKxVWUJVWUGwAv7VC2z280aVAFwI0_Jr0_Gr1lOx8S6xCaFVCjc4AY6r1j6r 4UM4x0Y48IcVAKI48JM4x0x7Aq67IIx4CEVc8vx2IErcIFxwCYjI0SjxkI62AI1cAE67vI Y487MxAIw28IcxkI7VAKI48JMxC20s026xCaFVCjc4AY6r1j6r4UMI8I3I0E5I8CrVAFwI 0_Jr0_Jr4lx2IqxVCjr7xvwVAFwI0_JrI_JrWlx4CE17CEb7AF67AKxVWUtVW8ZwCIc40Y 0x0EwIxGrwCI42IY6xIIjxv20xvE14v26r1j6r1xMIIF0xvE2Ix0cI8IcVCY1x0267AKxV WUJVW8JwCI42IY6xAIw20EY4v20xvaj40_WFyUJVCq3wCI42IY6I8E87Iv67AKxVWUJVW8 JwCI42IY6I8E87Iv6xkF7I0E14v26r4j6r4UJbIYCTnIWIevJa73UjIFyTuYvjfUoOJ5UU UUU X-CM-SenderInfo: 51xn3trlr6x35dzhxuhorxvhhfrp/ X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org Hi, Christoph! ÔÚ 2022/08/13 15:15, Christoph Hellwig дµÀ: > On Sat, Aug 13, 2022 at 03:09:58PM +0800, Yu Kuai wrote: >> Thanks for your reply. Do you think it's better to remove the rename >> support from dm? Or it's better to add such limit? > > It will probably be hard to entirely remove it. But documentation > and a rate limited warning discouraging it seems like a good idea. > . > I just found that not just rename, mount concurrent with device remove/create can trigger this problem as well: t1: t2 // create dm-0 with name test1 // mount /dev/mapper/test1 mount_bdev blkdev_get_by_path lookup_bdev // remove dm-0 // create dm-0 with different name test2 blkdev_get_by_dev // succeed Do you think it's ok to add such checking to prevent this problem? Thanks, Kuai