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Wed, 12 Nov 2025 21:53:57 -0800 (PST) Received: from dw-tp ([49.207.219.162]) by smtp.gmail.com with ESMTPSA id 41be03b00d2f7-bc365da0191sm937384a12.0.2025.11.12.21.53.51 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 12 Nov 2025 21:53:56 -0800 (PST) From: Ritesh Harjani (IBM) To: Christoph Hellwig , Dave Chinner Cc: Ojaswin Mujoo , Christian Brauner , djwong@kernel.org, john.g.garry@oracle.com, tytso@mit.edu, willy@infradead.org, dchinner@redhat.com, hch@lst.de, linux-xfs@vger.kernel.org, linux-kernel@vger.kernel.org, linux-ext4@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, jack@suse.cz, nilay@linux.ibm.com, martin.petersen@oracle.com, rostedt@goodmis.org, axboe@kernel.dk, linux-block@vger.kernel.org, linux-trace-kernel@vger.kernel.org Subject: Re: [RFC PATCH 0/8] xfs: single block atomic writes for buffered IO In-Reply-To: <20251113052337.GA28533@lst.de> Date: Thu, 13 Nov 2025 11:12:49 +0530 Message-ID: <87frai8p46.ritesh.list@gmail.com> References: <20251113052337.GA28533@lst.de> X-Stat-Signature: sh48k6h43hr8ssizjt9ggoombhyp6r6w X-Rspam-User: X-Rspamd-Queue-Id: 7857E140004 X-Rspamd-Server: rspam10 X-HE-Tag: 1763013238-707155 X-HE-Meta: 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 qKWUUtmO 0S1cduy5E3qp5sCehDCninP6JyYf9DmaxC5mvYQie032NLiMOHQ+SRjgQiF3Hq3ZVCngAnxiiKD8nLNBr8OJlcpiH2zsh6WhwaRrlwCShEHVnJaTD+XxNJ4E9fcy2w9M0T9M7BOjT1ycDY/vzJfbUCa711YQtnJ+P9KDDvv23nMb042tYpO6T6yXNkYn/h1abEpqKVaVITJSPAfAcIBoywu9dc9aTPMmFL08yVV+5Kpv/+MiK2QLIcLDZ2cDbU7YpmZrkpSYDjTqGLIA86YJdTSzCIgKnl6Ur6VbiS3kmIL2CtNhkr9nNh7BxdY4tvcGH1pkWBBlI1WfnF5avkn7FbBcSWFz1d+01TSQBr3EOtDJmsRUSWeNsAZBY8w3UC1Gsrz33jZTMJKyLyV/HWYZdzY8u6lreih2mwdqUR+jeV2OMiwHfXgWCuxTRZfpMZj46LC9vEauKdo6sz9fu/U/MUSSl7KbRPnLoe3pF 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: Christoph Hellwig writes: > On Thu, Nov 13, 2025 at 08:56:56AM +1100, Dave Chinner wrote: >> On Wed, Nov 12, 2025 at 04:36:03PM +0530, Ojaswin Mujoo wrote: >> > This patch adds support to perform single block RWF_ATOMIC writes for >> > iomap xfs buffered IO. This builds upon the inital RFC shared by John >> > Garry last year [1]. Most of the details are present in the respective >> > commit messages but I'd mention some of the design points below: >> >> What is the use case for this functionality? i.e. what is the >> reason for adding all this complexity? > > Seconded. The atomic code has a lot of complexity, and further mixing > it with buffered I/O makes this even worse. We'd need a really important > use case to even consider it. I agree this should have been in the cover letter itself. I believe the reason for adding this functionality was also discussed at LSFMM too... For e.g. https://lwn.net/Articles/974578/ goes in depth and talks about Postgres folks looking for this, since PostgreSQL databases uses buffered I/O for their database writes. -ritesh