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	id B204868AFE; Wed, 19 Jun 2024 10:02:18 +0200 (CEST)
Date: Wed, 19 Jun 2024 10:02:18 +0200
From: Christoph Hellwig <hch@lst.de>
To: John Garry <john.g.garry@oracle.com>
Cc: Keith Busch <kbusch@kernel.org>, Christoph Hellwig <hch@lst.de>,
	axboe@kernel.dk, sagi@grimberg.me, jejb@linux.ibm.com,
	martin.petersen@oracle.com, viro@zeniv.linux.org.uk,
	brauner@kernel.org, dchinner@redhat.com, jack@suse.cz,
	djwong@kernel.org, linux-block@vger.kernel.org,
	linux-kernel@vger.kernel.org, linux-nvme@lists.infradead.org,
	linux-fsdevel@vger.kernel.org, tytso@mit.edu, jbongio@google.com,
	linux-scsi@vger.kernel.org, ojaswin@linux.ibm.com,
	linux-aio@kvack.org, linux-btrfs@vger.kernel.org,
	io-uring@vger.kernel.org, nilay@linux.ibm.com,
	ritesh.list@gmail.com, willy@infradead.org, agk@redhat.com,
	snitzer@kernel.org, mpatocka@redhat.com, dm-devel@lists.linux.dev,
	hare@suse.de, Himanshu Madhani <himanshu.madhani@oracle.com>
Subject: Re: [PATCH v8 05/10] block: Add core atomic write support
Message-ID: <20240619080218.GA4437@lst.de>
References: <20240610104329.3555488-1-john.g.garry@oracle.com> <20240610104329.3555488-6-john.g.garry@oracle.com> <ZnCGwYomCC9kKIBY@kbusch-mbp.dhcp.thefacebook.com> <20240618065112.GB29009@lst.de> <91e9bbe3-75cf-4874-9d64-0785f7ea21d9@oracle.com> <ZnHDCYiRA9EvuLTc@kbusch-mbp.dhcp.thefacebook.com> <24b58c63-95c9-43d4-a5cb-78754c94cbfb@oracle.com>
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On Wed, Jun 19, 2024 at 08:59:33AM +0100, John Garry wrote:
> In this case, I would expect NOIOB >= atomic write boundary.
>
> Would it be sane to have a NOIOB < atomic write boundary in some other 
> config?
>
> I can support these possibilities, but the code will just get more complex.

I'd be tempted to simply not support the case where NOIOB is not a
multiple of the atomic write boundary for now and disable atomic writes
with a big fat warning (and a good comment in the soure code).  If users
show up with a device that hits this and want to use atomic writes we
can resolved it.