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Date: Fri, 21 Mar 2025 06:00:23 +0100
From: Christoph Hellwig <hch@lst.de>
To: Theodore Ts'o <tytso@mit.edu>
Cc: "Darrick J. Wong" <djwong@kernel.org>,
	Ritesh Harjani <ritesh.list@gmail.com>,
	Luis Chamberlain <mcgrof@kernel.org>, linux-fsdevel@vger.kernel.org,
	linux-mm@kvack.org, linux-block@vger.kernel.org,
	lsf-pc@lists.linux-foundation.org, david@fromorbit.com,
	leon@kernel.org, hch@lst.de, kbusch@kernel.org, sagi@grimberg.me,
	axboe@kernel.dk, joro@8bytes.org, brauner@kernel.org, hare@suse.de,
	willy@infradead.org, john.g.garry@oracle.com, p.raghav@samsung.com,
	gost.dev@samsung.com, da.gomez@samsung.com
Subject: Re: [LSF/MM/BPF TOPIC] breaking the 512 KiB IO boundary on x86_64
Message-ID: <20250321050023.GB1831@lst.de>
References: <Z9v-1xjl7dD7Tr-H@bombadil.infradead.org> <87o6xvsfp7.fsf@gmail.com> <20250320213034.GG2803730@frogsfrogsfrogs> <87jz8jrv0q.fsf@gmail.com> <20250321030526.GW89034@frogsfrogsfrogs> <20250321045604.GA1161423@mit.edu>
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User-Agent: Mutt/1.5.17 (2007-11-01)

On Fri, Mar 21, 2025 at 12:56:04AM -0400, Theodore Ts'o wrote:
> As I recall, in the eary days Linux's safety for DIO and Bufered I/O
> was best efforts, and other Unix system the recommendation to "don't
> mix the streams" was far stronger.  Even if it works reliably for
> Linux, it's still something I recommend that people avoid if at all
> possible.

It still is a best effort, just a much better effort now.  It's still
pretty easy to break the coherent.