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=-2.0 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM,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 C8AFEC433DF for ; Wed, 17 Jun 2020 23:39:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9272E21582 for ; Wed, 17 Jun 2020 23:39:39 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=gmx.net header.i=@gmx.net header.b="jr8/krd8" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726845AbgFQXji (ORCPT ); Wed, 17 Jun 2020 19:39:38 -0400 Received: from mout.gmx.net ([212.227.15.15]:58167 "EHLO mout.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726763AbgFQXjh (ORCPT ); Wed, 17 Jun 2020 19:39:37 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gmx.net; s=badeba3b8450; t=1592437172; bh=9qa7JsvfgCQj6s4iia5rNNJdW8JFoDc/NT7HJdEp5GU=; h=X-UI-Sender-Class:Subject:To:References:From:Date:In-Reply-To; b=jr8/krd8al0cr1awN5EG18YntYXDN++BXesdyuqTJ1CWuwETTmu8l6qPlXeQcGTV/ tucg9Hl2AziPyRld7tDgP2D9SWLQLA30rhYPOegsbDcICXSLULs6MIkwDNWPNHk8IF yGaMD37HztK9HjBqcq+BFIvkj7k1wPqhsn0w8cxI= X-UI-Sender-Class: 01bb95c1-4bf8-414a-932a-4f6e2808ef9c Received: from [0.0.0.0] ([149.28.201.231]) by mail.gmx.com (mrgmx004 [212.227.17.184]) with ESMTPSA (Nemesis) id 1MiacH-1jHc9s3sJz-00fh86; Thu, 18 Jun 2020 01:39:32 +0200 Subject: Re: [PATCH 2/4] btrfs: detect uninitialized btrfs_root::anon_dev for user visible subvolumes To: Josef Bacik , dsterba@suse.cz, Qu Wenruo , linux-btrfs@vger.kernel.org References: <20200616021737.44617-1-wqu@suse.com> <20200616021737.44617-3-wqu@suse.com> <0e274dc7-ac05-078a-2a2c-348e72745d45@suse.com> <20200617113109.GK27795@twin.jikos.cz> From: Qu Wenruo Autocrypt: addr=quwenruo.btrfs@gmx.com; prefer-encrypt=mutual; keydata= mQENBFnVga8BCACyhFP3ExcTIuB73jDIBA/vSoYcTyysFQzPvez64TUSCv1SgXEByR7fju3o 8RfaWuHCnkkea5luuTZMqfgTXrun2dqNVYDNOV6RIVrc4YuG20yhC1epnV55fJCThqij0MRL 1NxPKXIlEdHvN0Kov3CtWA+R1iNN0RCeVun7rmOrrjBK573aWC5sgP7YsBOLK79H3tmUtz6b 9Imuj0ZyEsa76Xg9PX9Hn2myKj1hfWGS+5og9Va4hrwQC8ipjXik6NKR5GDV+hOZkktU81G5 gkQtGB9jOAYRs86QG/b7PtIlbd3+pppT0gaS+wvwMs8cuNG+Pu6KO1oC4jgdseFLu7NpABEB AAG0IlF1IFdlbnJ1byA8cXV3ZW5ydW8uYnRyZnNAZ214LmNvbT6JAVQEEwEIAD4CGwMFCwkI BwIGFQgJCgsCBBYCAwECHgECF4AWIQQt33LlpaVbqJ2qQuHCPZHzoSX+qAUCWdWCnQUJCWYC bgAKCRDCPZHzoSX+qAR8B/94VAsSNygx1C6dhb1u1Wp1Jr/lfO7QIOK/nf1PF0VpYjTQ2au8 ihf/RApTna31sVjBx3jzlmpy+lDoPdXwbI3Czx1PwDbdhAAjdRbvBmwM6cUWyqD+zjVm4RTG rFTPi3E7828YJ71Vpda2qghOYdnC45xCcjmHh8FwReLzsV2A6FtXsvd87bq6Iw2axOHVUax2 FGSbardMsHrya1dC2jF2R6n0uxaIc1bWGweYsq0LXvLcvjWH+zDgzYCUB0cfb+6Ib/ipSCYp 3i8BevMsTs62MOBmKz7til6Zdz0kkqDdSNOq8LgWGLOwUTqBh71+lqN2XBpTDu1eLZaNbxSI ilaVuQENBFnVga8BCACqU+th4Esy/c8BnvliFAjAfpzhI1wH76FD1MJPmAhA3DnX5JDORcga CbPEwhLj1xlwTgpeT+QfDmGJ5B5BlrrQFZVE1fChEjiJvyiSAO4yQPkrPVYTI7Xj34FnscPj /IrRUUka68MlHxPtFnAHr25VIuOS41lmYKYNwPNLRz9Ik6DmeTG3WJO2BQRNvXA0pXrJH1fN GSsRb+pKEKHKtL1803x71zQxCwLh+zLP1iXHVM5j8gX9zqupigQR/Cel2XPS44zWcDW8r7B0 q1eW4Jrv0x19p4P923voqn+joIAostyNTUjCeSrUdKth9jcdlam9X2DziA/DHDFfS5eq4fEv ABEBAAGJATwEGAEIACYCGwwWIQQt33LlpaVbqJ2qQuHCPZHzoSX+qAUCXZw1rgUJCWpOfwAK CRDCPZHzoSX+qFcEB/95cs8cM1OQdE/GgOfCGxwgckMeWyzOR7bkAWW0lDVp2hpgJuxBW/gy fmtBnUaifnggx3EE3ev8HTysZU9q0h+TJwwJKGv6sUc8qcTGFDtavnnl+r6xDUY7A6GvXEsS oCEEynby72byGeSovfq/4AWGNPBG1L61Exl+gbqfvbECP3ziXnob009+z9I4qXodHSYINfAk ZkA523JGap12LndJeLk3gfWNZfXEWyGnuciRGbqESkhIRav8ootsCIops/SqXm0/k+Kcl4gG UO/iD/T5oagaDh0QtOd8RWSMwLxwn8uIhpH84Q4X1LadJ5NCgGa6xPP5qqRuiC+9gZqbq4Nj Message-ID: <38c70792-fb5b-f986-e4cc-087efcb3d54b@gmx.com> Date: Thu, 18 Jun 2020 07:39:28 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.9.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: quoted-printable X-Provags-ID: V03:K1:tz8IWc7vshQ0UtDv3a0xtYjx9ANvssDnC1tkz/5i71+cNtddtXP jIWqC1o0NzhoQAGk8AGyCetvKRdhnxzIJOVChBP+XRkpfy/8xXjzzVajvNgCW7SWVWCPiZK KJbPXZ0WqwlK5Tz34ddScdvzzDfJ/dZx5GfFAT7mj3V/SNoC4mzYnQAliS+c9wuexlI6aKH mK27dOa5tgc5ITKI1jf9Q== X-UI-Out-Filterresults: notjunk:1;V03:K0:3aiZDh+I8YE=:1Xx0bbldJUrcyG+/fkDv1S u5qGsBZV5VcJoQmLtE0l3bG00xM+bZMxPZjZ515vk3MMYYkF3pmVO/VPRuNfiG5ZHyKtvPFK3 AUieiC3fZEzplIUJb1JzZuyuit/y4oHk7LFHVAlaqO31TRTt95GxkCIWt9E4eBr3MUaxYXSw1 kkKaWQYXs6W9Q7SkNyJQq3oDWvQucyLXVXksjRMepJ4VbKwBqYkmx90RXOBEGiHM84AVsaEEb 3uPiDhrusc3LmTUGOzh7cK4SMVrn/ws+KdoTTPbA8zSf6mc/biBsj4IF9/rmqo2j9ZvM79LnW TIpUS0hCRUNiFC3RmMxBEh3C6+MQoFEgiApypDhxLydjmGzzx4yQVyUK+ILV9Xx6R6zGeYNxP XJPehV5id+p5hUtQFsJLIvpzdaEbX3OTlKeq7AfDEjK17bzB88y6FQei11BnHerzTIJ8Mi2Lj L+iiDqSQs2kgB+nTG/7tq8+M0FRzhcDT3ZxtpGzLdjkXqz6prlM/RpnVee1ggSWslZaOVUoEA avO4KWBpXElXdf5mbfRQb9FQhysTG8BovMPfx8ypMjp/8TmZjVh/Ba3/VovS0lWhYbtYB2jmT LWNhU/aUtwlHBQVXLwseKcXwHRNIj9E++2utUhIUtCDZ7Y6NfsU501R9Sb7CxIjvXQRuyQCfO MmQeGyA3fpNsAC/S4xM0hkUUPQmV8CgOBTtCidUvQy20nDPy459dINlVAFoiNo5eiNdc3x5R9 DOcc9INDkOjMMOwXtvJDqGB1UlzYQAiIi54+qzHzHtygd8+Npvieg1xiuq+LzqcbsEmYXjVYU X+1z9Iq6kjdrnxMB8dnV6mu7vyGwbfVoQPWS3hewR5ilY6o8HJjyK4kUhlIVXcbp2nCpu1seC JTbp+vS6yt6hZF7q7DJ2/63ALtVc8nbGb4zJT618TnEd5goFCuJWbOmbc9nY0ONknDP3Y7kbo oFlRoNsjgNV9X6UZq/xnwlaydFAunFKxRfC87q9tIKv0CVR3IJnZyx6UyLORSW6Oqu+nk0jZ8 MM+gBaHFPgFxATX2a9eLGrY3A08tU61MiCW/nOalIZN3aNvdNRVWpqY0sirfcI+fIglVxUfzs 93TZesV6iR+urVyYqDJGTGo7u+nA4tSPTTQPH1BaCeqDq6kzWG6l34IS5DQFDCdIUaz7uGXIc 5DEhMrV8Uy0UTwnFZI+MMHBUdADs5MFxtpn7Au10ZF0maCijWzTI4mPT8A8jU7z3ktCW8ARfF x/JCQHF/y9qAcJ8dR Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org On 2020/6/17 =E4=B8=8B=E5=8D=889:37, Josef Bacik wrote: > On 6/17/20 7:31 AM, David Sterba wrote: >> On Wed, Jun 17, 2020 at 07:49:33AM +0800, Qu Wenruo wrote: >>>>>> Can we handle stat->dev not having a device set?=C2=A0 Or will this >>>>>> blow up >>>>>> in other ways?=C2=A0 Thanks, >>>>> >>>>> We can handle it without any problem, just users get confused. >>>>> >>>>> As a common practice, we use different bdev as a namespace for >>>>> different >>>>> subvolumes. >>>>> Without a valid bdev, some user space tools may not be able to >>>>> distinguish inodes in different subvolumes. >>>>> >>>> >>>> Alright that's fine then.=C2=A0 But I feel like stat is one of those = things >>>> that'll flood the console, can we put this somewhere else that's goin= g >>>> to be hit less? Thanks, >>> >>> Unfortunately, stat() is the only user of btrfs_root::anon_dev. >>> >>> While fortunately, the logical is pretty simple, even without the safe >>> net we can understand the lifespan pretty well. >>> >>> I'm fine to drop this patch if you're concerned about the possible >>> warning flood, as the benefit is really not that much. >> >> It could be a developer-only warning but if there's a root with a bad >> anon_dev, a simple 'ls -l' would flood the log for sure. >> > > We'll know in btrfs_init_fs_root() when get_anon_bdev() fails right?=C2= =A0 > Can't we just complain then?=C2=A0 That seems less spammy.=C2=A0 Thanks, That's exactly where we do the allocation, that would be something like warning about the allocation result. That's why I'm fine to drop this patch if it's too spammy. Thanks, Qu > > Josef