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Date: Wed, 23 Apr 2025 07:42:51 +0200
From: Christoph Hellwig <hch@lst.de>
To: "Darrick J. Wong" <djwong@kernel.org>
Cc: John Garry <john.g.garry@oracle.com>, brauner@kernel.org, hch@lst.de,
	viro@zeniv.linux.org.uk, jack@suse.cz, cem@kernel.org,
	linux-fsdevel@vger.kernel.org, dchinner@redhat.com,
	linux-xfs@vger.kernel.org, linux-kernel@vger.kernel.org,
	ojaswin@linux.ibm.com, ritesh.list@gmail.com,
	martin.petersen@oracle.com, linux-ext4@vger.kernel.org,
	linux-block@vger.kernel.org, catherine.hoang@oracle.com,
	linux-api@vger.kernel.org
Subject: Re: [PATCH v7 11/14] xfs: add xfs_file_dio_write_atomic()
Message-ID: <20250423054251.GA23087@lst.de>
References: <20250415121425.4146847-1-john.g.garry@oracle.com> <20250415121425.4146847-12-john.g.garry@oracle.com> <20250421040002.GU25675@frogsfrogsfrogs> <2467484b-382b-47c2-ae70-4a41d63cf4fc@oracle.com> <20250421164241.GD25700@frogsfrogsfrogs>
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User-Agent: Mutt/1.5.17 (2007-11-01)

On Mon, Apr 21, 2025 at 09:42:41AM -0700, Darrick J. Wong wrote:
> Well it turns out that was a stupid question -- zoned=1 can't be enabled
> with reflink, which means there's no cow fallback so atomic writes just
> plain don't work:

Exactly.  It is still on my todo list to support it, but there are a
few higher priority items on it as well, in addition to constant
interruptions for patch reviews :)

> I /think/ all you'd have to do is create an xfs_zoned_end_atomic_io
> function that does what xfs_zoned_end_io but with a single
> tr_atomic_ioend transaction; figure out how to convey "this is an
> atomic out of place write" to xfs_end_ioend so that it knows to call
> xfs_zoned_end_atomic_io; and then update the xfs_get_atomic_write*
> helpers.

Roughly, yes.