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 9D0B5C433F5 for ; Tue, 17 May 2022 00:27:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230096AbiEQA1b (ORCPT ); Mon, 16 May 2022 20:27:31 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38726 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229802AbiEQA13 (ORCPT ); Mon, 16 May 2022 20:27:29 -0400 Received: from mout.gmx.net (mout.gmx.net [212.227.17.20]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5CA092E6A7 for ; Mon, 16 May 2022 17:27:26 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gmx.net; s=badeba3b8450; t=1652747243; bh=qh5xa5xzyHTBihJw2KIx2Yzz1pqAHBGDEp3OlDExmmk=; h=X-UI-Sender-Class:Date:Subject:To:Cc:References:From:In-Reply-To; b=Ac5prouBwzerv4cDpaqV0MCP75zkTkQGtuTHkuzRP97HwEIDFLv/W7qgRbiwo5NK2 qfJ9gtMxDmFS2bGvTlHGyzdUr83Ya3hlbujRkWNHfL0GJA6JlouvF8r8qsXa8bgFZJ pL0rphrH+fwJWIsgTm6TY+rISmVSWU3WCrJHSR14= X-UI-Sender-Class: 01bb95c1-4bf8-414a-932a-4f6e2808ef9c Received: from [0.0.0.0] ([149.28.201.231]) by mail.gmx.net (mrgmx104 [212.227.17.174]) with ESMTPSA (Nemesis) id 1MORAU-1oFRqe1DHK-00PtEj; Tue, 17 May 2022 02:27:23 +0200 Message-ID: <6f64a575-2dec-78e8-51a6-009ea99a27d4@gmx.com> Date: Tue, 17 May 2022 08:27:19 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.9.0 Subject: Re: [PATCH] btrfs: prevent remounting to v1 space cache for subpage mount Content-Language: en-US To: Josef Bacik , Qu Wenruo Cc: linux-btrfs@vger.kernel.org References: <1e09cf20ca9309f2b9daf57136c3e2c1b22f94f6.1652682383.git.wqu@suse.com> From: Qu Wenruo In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: quoted-printable X-Provags-ID: V03:K1:YgUJNA9wDE04NhKzylzO3sUForzrMSuK0PYkDlOPEUKG7FuXcQJ XgWfMMPGLwhkT/uiHVonfNQ6ajaGlChzYgbyyA+sDFDnHFpIOZQWYs00vJ18tsosLano0W0 ZIt1XCcvq1wDC/YLLxL0Gk8ZuM3pGQy2ZokdUQ/4LItnDXdkhdDA/AmoVVCGf+puPpbPR+n vgqKmHcF33agU9TGKN/Zg== X-UI-Out-Filterresults: notjunk:1;V03:K0:67Tc/qO+HY8=:EZImp8G5KBZEIm2HdqNOCT Fs32N3HqChKzGwHTZmDmEZblYifNoDVZnK0UNqsyUHXyZwDweIs5s1pNDsDfP6HSLUNlVaY8X 1Z9JQ1XBjdeRuMD8hZaY27HDHjc9TO+wAnEL9E6PIKph60SjOuEvf9I57taum088JxzSLTedX E9COmckSE2mC4nTIFQktqhEHYbgn8z7FEY5adpGu1oGeraUbjaxRV1kAQM4tyqJ/LCjFERsKk x9XzSoILC4huPgJEUWoK80gN4SIpUkZ49BY8PVRmCxo1ab+1QkZnsNcFGkwdGf5O+A0i5ZFa9 Ow47d3E0x2OOzBLs+MB2NdBV0na6kwi1Gu0Z1L0ObMOnIYqRFgi5RD/jo0y1YQ1MgquTF+c5V YXMQNCCkPxc1GeT5JUeU6t9x4mH3CjY1Z2x5duQZN6R284vAVUwR8vzGFP6134KWZdCvKHCEb 7Mpjmno6qg4a0YmAFYcaVxAdp3VxOc+FJvvouT32v61PtgnY3XS26SAdfbRq7YoSGsbWoVWPy wxmzkc1MY7mHKvag3HbegXYXZYho2fDMUk/xw9Ca1e78qiqO6r8tsmB7Mc49B4Ymmh9+txc06 tpoC1bxGlJgVJX5rb5MSyzUs0kxBziThCkAso/ysuN6+jFS3vSiKKbjOcSjUT0z1pPlrfMYoy LKa/po2iMue4tJMLYeg0jL/a4+cJ4c92GV2KH0vwMLVRiunrYX1qQPXR8NoBevf4QFEQ6kHGk qt4XWTHdP1jOR5mooIn3REGMo+H25mHzk5v72XCWi104NNG68PTKBvT/83KT8MaL13kTzCoip N7kZ5MSYXjAApXjwQSaA090la0Wc57tXelbNs6/pJZmEmVUsEto5ArSpc8ZNf68xZGacS/Buw TTkzbxapM0bPEEbWJ1Mjmj19+myHgy/Cln6H8ta8OUZQFCZPEglCLMswxFEzn2Wz4UB2LpM/p s3YZOhoIPB7aiXuw5QNxkDuGkWja04ULIEfFSqSxu45H5AyAfan1m9hJFiZEYz22fQkQ8cXog MgqabwbZjMCUH7tCRVTlP4i3+555roNqUYlm9JK5SuqeTrsvCAySlvut7xQ9/RDPG5kaeL/uh Ujn03+q608HbOSk/Qn+m0Bale6CmrcIWz8q4U+Sbb8AkHSTAljpvIntQQ== Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org On 2022/5/16 23:05, Josef Bacik wrote: > On Mon, May 16, 2022 at 02:26:53PM +0800, Qu Wenruo wrote: >> Upstream commit 9f73f1aef98b ("btrfs: force v2 space cache usage for >> subpage mount") forces subpage mount to use v2 cache, to avoid >> deprecated v1 cache which doesn't support subpage properly. >> >> But there is a loophole that user can still remount to v1 cache. >> >> The existing check will only give users a warning, but not really >> prevents the users to do the remount. >> >> Although remounting to v1 will not cause any problems since the v1 cach= e >> will always be marked invalid when mounted with a different page size, >> it's still better to prevent v1 cache at all for subpage mounts. >> >> Signed-off-by: Qu Wenruo >> --- >> fs/btrfs/super.c | 8 ++++++++ >> 1 file changed, 8 insertions(+) >> >> diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c >> index b1fdc6a26c76..1617528a3367 100644 >> --- a/fs/btrfs/super.c >> +++ b/fs/btrfs/super.c >> @@ -1985,6 +1985,14 @@ static int btrfs_remount(struct super_block *sb,= int *flags, char *data) >> if (ret) >> goto restore; >> >> + /* V1 cache is not supported for subpage mount. */ >> + if (fs_info->sectorsize < PAGE_SIZE && >> + btrfs_test_opt(fs_info, SPACE_CACHE)) { >> + btrfs_warn(fs_info, >> + "v1 space cache is not supported for page size %lu with sectorsize %u= ", >> + PAGE_SIZE, fs_info->sectorsize); > > Shouldn't we be doing ret =3D -EINVAL; here? Thanks, > > Josef Oh, forgot that. Thanks for catching it, Qu