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Date: Wed, 18 Feb 2026 07:47:39 +0100
From: Christoph Hellwig <hch@lst.de>
To: Dave Chinner <dgc@kernel.org>
Cc: Andres Freund <andres@anarazel.de>,
	Pankaj Raghav <pankaj.raghav@linux.dev>, Jan Kara <jack@suse.cz>,
	Ojaswin Mujoo <ojaswin@linux.ibm.com>, linux-xfs@vger.kernel.org,
	linux-mm@kvack.org, linux-fsdevel@vger.kernel.org,
	lsf-pc@lists.linux-foundation.org, djwong@kernel.org,
	john.g.garry@oracle.com, willy@infradead.org, hch@lst.de,
	ritesh.list@gmail.com, Luis Chamberlain <mcgrof@kernel.org>,
	dchinner@redhat.com, Javier Gonzalez <javier.gonz@samsung.com>,
	gost.dev@samsung.com, tytso@mit.edu, p.raghav@samsung.com,
	vi.shah@samsung.com
Subject: Re: [LSF/MM/BPF TOPIC] Buffered atomic writes
Message-ID: <20260218064739.GA8881@lst.de>
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On Wed, Feb 18, 2026 at 12:04:43PM +1100, Dave Chinner wrote:
> > > > I'd call it RWF_WRITETHROUGH but otherwise it makes sense.
> > > > 
> > > 
> > > One naive question: semantically what will be the difference between
> > > RWF_DSYNC and RWF_WRITETHROUGH?
> 
> None, except that RWF_DSYNC provides data integrity guarantees.

Which boils down to RWF_DSYNC still writing out the inode and flushing
the cache.

> > Which
> > wouldn't be needed for RWF_WRITETHROUGH, right?
> 
> Correct, there shouldn't be any data integrity guarantees associated
> with plain RWF_WRITETHROUGH.

Which makes me curious if the plain RWF_WRITETHROUGH would be all
that useful.