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Date: Fri, 12 Jul 2024 06:56:15 +0200
From: Christoph Hellwig <hch@lst.de>
To: Dave Chinner <david@fromorbit.com>
Cc: "Darrick J. Wong" <djwong@kernel.org>,
	John Garry <john.g.garry@oracle.com>, chandan.babu@oracle.com,
	dchinner@redhat.com, hch@lst.de, viro@zeniv.linux.org.uk,
	brauner@kernel.org, jack@suse.cz, linux-xfs@vger.kernel.org,
	linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	catherine.hoang@oracle.com, martin.petersen@oracle.com
Subject: Re: [PATCH v2 07/13] xfs: Introduce FORCEALIGN inode flag
Message-ID: <20240712045615.GA4833@lst.de>
References: <20240705162450.3481169-1-john.g.garry@oracle.com> <20240705162450.3481169-8-john.g.garry@oracle.com> <20240711025958.GJ612460@frogsfrogsfrogs> <ZpBouoiUpMgZtqMk@dread.disaster.area>
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On Fri, Jul 12, 2024 at 09:20:26AM +1000, Dave Chinner wrote:
> I don't think we should error out the mount because reflink and
> forcealign are enabled - that's going to be the common configuration
> for every user of forcealign, right? I also don't think we should
> throw a corruption error if both flags are set, either.
> 
> We're making an initial *implementation choice* not to implement the
> two features on the same inode at the same time. We are not making a
> an on-disk format design decision that says "these two on-disk flags
> are incompatible".

Oh, right forcealign is per-inode.  In that case we just need to
ensure it never happens.  Which honestly might be a bit confusing if
you can reflink for some files and not others, but that's a separate
discussion.