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s=arc-20220608; d=hostedemail.com; t=1771397386; a=rsa-sha256; cv=none; b=vnJOAjys7xiqnftnY5m0CaoHd6D53bOXdRLKQD20U+hlk5ARA2RNf2/WIwzofWl/xIvsVA pDqMK5R9vbky7RvCAL5FqRh3RtErvQKEgHR9o+hyDMlHS1doEXJa4yg+JqigR5AgdRCP58 EqkSpVfPyjz9xQ77ejfrGbOh6uerYdc= ARC-Authentication-Results: i=1; imf08.hostedemail.com; dkim=none; spf=pass (imf08.hostedemail.com: domain of hch@lst.de designates 213.95.11.211 as permitted sender) smtp.mailfrom=hch@lst.de; dmarc=pass (policy=none) header.from=lst.de Received: by verein.lst.de (Postfix, from userid 2407) id 8ED2868BFE; Wed, 18 Feb 2026 07:49:42 +0100 (CET) Date: Wed, 18 Feb 2026 07:49:42 +0100 From: Christoph Hellwig To: Dave Chinner Cc: Ojaswin Mujoo , Jan Kara , Pankaj Raghav , linux-xfs@vger.kernel.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, lsf-pc@lists.linux-foundation.org, Andres Freund , djwong@kernel.org, john.g.garry@oracle.com, willy@infradead.org, hch@lst.de, ritesh.list@gmail.com, Luis Chamberlain , dchinner@redhat.com, Javier Gonzalez , gost.dev@samsung.com, tytso@mit.edu, p.raghav@samsung.com, vi.shah@samsung.com Subject: Re: [Lsf-pc] [LSF/MM/BPF TOPIC] Buffered atomic writes Message-ID: <20260218064942.GB8881@lst.de> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.17 (2007-11-01) X-Rspamd-Queue-Id: 63C60160004 X-Stat-Signature: y7cex8t15r6dn5xr9f93amd18qg5n1b6 X-Rspam-User: X-Rspamd-Server: rspam12 X-HE-Tag: 1771397386-179607 X-HE-Meta: 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 x9wkT62/ BvD8kTm6GDTsT9VtbyGi9Xk97P1jCeAmZwEaQC2Gw3ULIbVaogKQqLYFUkRvv8R7yU6ufwU4u1GZ9Ko8al8J1UzcspSNEHsrPGRqueyEB6j1MTVHzW17bs++I8h8FX2eIKEt0pz7AVTHed2aPhVDEav/fJ13Qp1q6mfQ3fRjVitHHHik= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Wed, Feb 18, 2026 at 11:26:06AM +1100, Dave Chinner wrote: > ISTR mentioning that we should be doing exactly this (grab page > cache pages, fill them and submit them through the DIO path) for > O_DSYNC buffered writethrough IO a long time again. Yes, multiple times. And I did a few more times since then. > Regardless, we are here again with proposals for RWF_ATOMIC and > RWF_WRITETHROUGH and a suggestion that maybe we should vector > buffered writethrough via the DIO path..... > > Perhaps it's time to do this? Yes. > FWIW, the other thing that write-through via the DIO path enables is > true async O_DSYNC buffered IO. Right now O_DSYNC buffered writes > block waiting on IO completion through generic_sync_write() -> > vfs_fsync_range(), even when issued through AIO paths. Vectoring it > through the DIO path avoids the blocking fsync path in IO submission > as it runs in the async DIO completion path if it is needed.... It's only true if we can do the page cache updates non-blocking, but in many cases that should indeed be possible.