From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mout.gmx.net (mout.gmx.net [212.227.17.20]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D4263155757; Thu, 6 Feb 2025 20:32:46 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=212.227.17.20 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738873968; cv=none; b=OnraD3saxjMHIRJl+sdoLRdjui/fu5VRW0MVh94VQnXgOFVHR+jNQCNw3rKmIDrGySp1QRajzhjnfMKPxWBMg57k8U+ELroB+hMOq8jPeGT1H5C4FFQeCgEL+bgZwxJ6Pi6GrZndD6Z/Q9BSpYLUTATXzqxPpNSxzDhoBEq+oog= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738873968; c=relaxed/simple; bh=jYRWPJl3vxi1pMnmu7IOIQOUwElB6wg+kD4zTfe6PWQ=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=FQLGfmc/LfC2FCQXMkeojnWc+MZ986b/UvvzXLiKVR4YnyN8QyK+USV6I2cnx2TNndm8SjhimC1AGAu1IYnlut0NUykPegG0esCjLlWHl1DuxuTWNUPeijzLb5eyxAVIMbeyzIfIbv8tpcb3ldZPFTrf1qcaj6YdUhv86wb7R9w= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=gmx.com; spf=pass smtp.mailfrom=gmx.com; dkim=pass (2048-bit key) header.d=gmx.com header.i=quwenruo.btrfs@gmx.com header.b=cqoeUZtX; arc=none smtp.client-ip=212.227.17.20 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=gmx.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmx.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmx.com header.i=quwenruo.btrfs@gmx.com header.b="cqoeUZtX" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmx.com; s=s31663417; t=1738873964; x=1739478764; i=quwenruo.btrfs@gmx.com; bh=9R+2vquaROtNZYSPIBsKoJzoSsjO0LkDiuYj8vkxDSk=; h=X-UI-Sender-Class:Message-ID:Date:MIME-Version:Subject:To:Cc: References:From:In-Reply-To:Content-Type: Content-Transfer-Encoding:cc:content-transfer-encoding: content-type:date:from:message-id:mime-version:reply-to:subject: to; b=cqoeUZtXVpxRRmmPEFKsm7Vq8LoLsMZOl+AxSQGsUgFyIpdlq7jQzb8dBqeZ+LJW 2rsbAEnH16aX7R5oZAL/mH5qYF97U0W/rrkFIhnL42M5Pv+IPxUObFCq3no7i6BqL Rnr93Eh3Qlf4u1ScK0a2bB/nly/T2iK+71v/ifAFrwdx5MmZ3kbsZKgXCCzjcd4+l NvGwQyIeQ3Syei29l9836sFUnrtIfd8dV/iwF8VzTf9YPI8zHn0Mvc1ozE4Jhr73G fhgETjenruwUL+GSKg124Tm4VMhAsZPQO9uzTA7QrtgfXUE4wUAnD29n3eNLPHiIR DZGYJCMj8IHeKIrWYg== X-UI-Sender-Class: 724b4f7f-cbec-4199-ad4e-598c01a50d3a Received: from [172.16.0.191] ([159.196.52.54]) by mail.gmx.net (mrgmx105 [212.227.17.174]) with ESMTPSA (Nemesis) id 1MzhjF-1tSqxm2IyH-00zywp; Thu, 06 Feb 2025 21:32:44 +0100 Message-ID: Date: Fri, 7 Feb 2025 07:02:38 +1030 Precedence: bulk X-Mailing-List: linux-btrfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2] btrfs: always fallback to buffered write if the inode requires checksum To: "hch@infradead.org" , Qu Wenruo Cc: linux-btrfs@vger.kernel.org, Jan Kara , linux-fsdevel@vger.kernel.org, linux-mm@kvack.org References: Content-Language: en-US From: Qu Wenruo Autocrypt: addr=quwenruo.btrfs@gmx.com; keydata= xsBNBFnVga8BCACyhFP3ExcTIuB73jDIBA/vSoYcTyysFQzPvez64TUSCv1SgXEByR7fju3o 8RfaWuHCnkkea5luuTZMqfgTXrun2dqNVYDNOV6RIVrc4YuG20yhC1epnV55fJCThqij0MRL 1NxPKXIlEdHvN0Kov3CtWA+R1iNN0RCeVun7rmOrrjBK573aWC5sgP7YsBOLK79H3tmUtz6b 9Imuj0ZyEsa76Xg9PX9Hn2myKj1hfWGS+5og9Va4hrwQC8ipjXik6NKR5GDV+hOZkktU81G5 gkQtGB9jOAYRs86QG/b7PtIlbd3+pppT0gaS+wvwMs8cuNG+Pu6KO1oC4jgdseFLu7NpABEB AAHNIlF1IFdlbnJ1byA8cXV3ZW5ydW8uYnRyZnNAZ214LmNvbT7CwJQEEwEIAD4CGwMFCwkI BwIGFQgJCgsCBBYCAwECHgECF4AWIQQt33LlpaVbqJ2qQuHCPZHzoSX+qAUCZxF1YAUJEP5a sQAKCRDCPZHzoSX+qF+mB/9gXu9C3BV0omDZBDWevJHxpWpOwQ8DxZEbk9b9LcrQlWdhFhyn xi+l5lRziV9ZGyYXp7N35a9t7GQJndMCFUWYoEa+1NCuxDs6bslfrCaGEGG/+wd6oIPb85xo naxnQ+SQtYLUFbU77WkUPaaIU8hH2BAfn9ZSDX9lIxheQE8ZYGGmo4wYpnN7/hSXALD7+oun tZljjGNT1o+/B8WVZtw/YZuCuHgZeaFdhcV2jsz7+iGb+LsqzHuznrXqbyUQgQT9kn8ZYFNW 7tf+LNxXuwedzRag4fxtR+5GVvJ41Oh/eygp8VqiMAtnFYaSlb9sjia1Mh+m+OBFeuXjgGlG VvQFzsBNBFnVga8BCACqU+th4Esy/c8BnvliFAjAfpzhI1wH76FD1MJPmAhA3DnX5JDORcga CbPEwhLj1xlwTgpeT+QfDmGJ5B5BlrrQFZVE1fChEjiJvyiSAO4yQPkrPVYTI7Xj34FnscPj /IrRUUka68MlHxPtFnAHr25VIuOS41lmYKYNwPNLRz9Ik6DmeTG3WJO2BQRNvXA0pXrJH1fN GSsRb+pKEKHKtL1803x71zQxCwLh+zLP1iXHVM5j8gX9zqupigQR/Cel2XPS44zWcDW8r7B0 q1eW4Jrv0x19p4P923voqn+joIAostyNTUjCeSrUdKth9jcdlam9X2DziA/DHDFfS5eq4fEv ABEBAAHCwHwEGAEIACYCGwwWIQQt33LlpaVbqJ2qQuHCPZHzoSX+qAUCZxF1gQUJEP5a0gAK CRDCPZHzoSX+qHGpB/kB8A7M7KGL5qzat+jBRoLwB0Y3Zax0QWuANVdZM3eJDlKJKJ4HKzjo B2Pcn4JXL2apSan2uJftaMbNQbwotvabLXkE7cPpnppnBq7iovmBw++/d8zQjLQLWInQ5kNq Vmi36kmq8o5c0f97QVjMryHlmSlEZ2Wwc1kURAe4lsRG2dNeAd4CAqmTw0cMIrR6R/Dpt3ma +8oGXJOmwWuDFKNV4G2XLKcghqrtcRf2zAGNogg3KulCykHHripG3kPKsb7fYVcSQtlt5R6v HZStaZBzw4PcDiaAF3pPDBd+0fIKS6BlpeNRSFG94RYrt84Qw77JWDOAZsyNfEIEE0J6LSR/ In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: quoted-printable X-Provags-ID: V03:K1:cRQTi1qJo2eAixYQuee6+vk0gajfHyEYgIXNP1vsdNHKU3ytq8a uuB9xsRxXiuELi3fSA5fzYKr7Hx6rM+5u4OJ94Wl93muZSrI9UA0A+iJwlIR0BXkuXBvGnM PZbrPlHx62X6f3DrWbj2j/yE3B6HlbEtWzfGoF3GPWbM3IfJDjVaOrvdj9bhTuW7Fp76Lm9 LonIg80uwC4+gVY29qojA== X-Spam-Flag: NO UI-OutboundReport: notjunk:1;M01:P0:bAPSaGPjSMM=;A40M8/XugEnMLhwIE8apqxS8O5N 3QBTqotDk/4kZeHFO5Wm5oBaxOIEjAlGHtKD0mP6XaGeOGE23SWTrUgvJf2MpAGMuTqcXtw/L 5FhwxZAVsr84W4BekxEfN8yITFXPVi/ZfdD13NvGdZsH1C1TmG8k02uwnFDvh4gab6cct0Fea 7WQagvc9G2IAjm5AA1kUgEb/p9vq/CVQpAB1jq4w4gZm1HqeRudllErZUMucdHIJHziM9etB/ rwfTZVQ4kqOXuc0lW5qnVhkIX9zbY5a+gdb9sUaB9at/fpVUt+BtLfgdoPz7qcKL7JZvdnf7N J/LjpMES3Am+2x/VVYGsyO67WeS5V6fdX4Iy97hv873jr1aYmHjMM/0pjVoFHyyyvMfJytVMp P7T1GeJpaFCJLfTqK04fjJLa1KBinvdLKX2G75qWK72aUc7f2VltyaqYxBhfi0lKvP9sQ6ElP NN0x5wtphx0MrB7poE9mMK1lkLerGZR78zEt8iO92SkzUiZG4uQWazuuQyntWAQl8pvhk4UOq 2nfIePDWsjxRfa4QpaBh9QHUA09Nx4pVRlCNyI3sSlNPw3EFazpmrV/17DmG9HvfTxt7rUKEd UlL620vp/g3FmZyuluyGomP5Zm6N6K3Qku+mwpsG7mW8t5DtjEbLQxtRQvtmLZ6nea+FwHfHJ lc1BSUrhYvq/khQokQyZ+YEfjkMoSZOLR9p7k0cW/DBGndkflKapZh4cpjjcH1eLzPcJeJjLR fTyTkNKlbTMWQ1Uluyb1CxbC1yT4Gs+HJ5tzhKlZJTBXbUUwteb2ehxWLCDb0G5z0J5Y53ZXe USfi/FGOHQajFX5iQa2H42vVD+yZhK07XWlv5duCLGGO3ZSOxanlVso3bkCNDDOzAEVnrjEo5 PKJEzXvsAVmc4dBiI9M4GHzGQFleRHy3MbRlu1nVVD/EF/VcMZmZTjRiO21uQ9IrwHgltCEt7 ZGe0i5syO+Qh1Q7J9VszAYgb5OOZg/bQmHNQSfLiiRGjSMaxfjqJZvGnwoxhqFA9Y7xko++9B 7eFySf6XXsOM0g1s22Z9PRwDntHe9oHRLULw44L5xqCDD/XOY4oaOHxu07ShIZ7xTtwLqfxMu x/kEC14LL3ePzLZeOjqDDAwjejk8ailB/BL5RClg9/oqo/8am9dAxxeppwmmmsCGtBGY/Addz EL60dmVazcyERelHgmdt/7zzZSaGThsxAbBrynlJY8XvlFLrJkH7XL7SMFAuJeWVi2CGVyVgj fwYUOZGr2HZl/rsPxXtmCbK9O19T9iIjFhqLv2PQpQwXE0Jq8PSKJ9gZN6Lid3r12HKXrMzpU Pm7G0VoJ9nB1ia/HFDDSW+6hPSk80qFxJvdxovdXVK8wmLXFRxMiq4Fvo4Jv3aD7LPYhZC9bC lLFUrg6jLFzO7n+d0NQz/tviVloArlFSni+8AbE3IBN4z1exj3mEwgjLwS =E5=9C=A8 2025/2/7 00:43, hch@infradead.org =E5=86=99=E9=81=93: > On Tue, Feb 04, 2025 at 02:00:23PM +1030, Qu Wenruo wrote: >> [BUG] >> It is a long known bug that VM image on btrfs can lead to data csum >> mismatch, if the qemu is using direct-io for the image (this is commonl= y >> known as cache mode none). >> >> [CAUSE] >> Inside the VM, if the fs is EXT4 or XFS, or even NTFS from Windows, the >> fs is allowed to dirty/modify the folio even the folio is under >> writeback (as long as the address space doesn't have AS_STABLE_WRITES >> flag inherited from the block device). > > Btw, can you add an xfstests that reproduces this by modifying pages > under direct I/O? That would be really helpful to verify the code when > we want to turn back on real direct I/O eventually when the VM is fixed > to prevent the modifications. Sure, although I'm afraid it will need to be a C program instead. Thanks, Qu