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References: <20211109083309.584081-1-hch@lst.de> <20211109083309.584081-24-hch@lst.de>
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From: Dan Williams <dan.j.williams@intel.com>
Date: Tue, 23 Nov 2021 18:49:06 -0800
Message-ID: <CAPcyv4gVTAddA2cGFKgt5yJVTozxfQgstj3kicZAk2mZX+E1Og@mail.gmail.com>
Subject: Re: [PATCH 23/29] xfs: use IOMAP_DAX to check for DAX mappings
To: Christoph Hellwig <hch@lst.de>
Cc: Mike Snitzer <snitzer@redhat.com>, Ira Weiny <ira.weiny@intel.com>, 
	device-mapper development <dm-devel@redhat.com>, linux-xfs <linux-xfs@vger.kernel.org>, 
	Linux NVDIMM <nvdimm@lists.linux.dev>, linux-s390 <linux-s390@vger.kernel.org>, 
	linux-fsdevel <linux-fsdevel@vger.kernel.org>, linux-erofs@lists.ozlabs.org, 
	linux-ext4 <linux-ext4@vger.kernel.org>, virtualization@lists.linux-foundation.org
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On Tue, Nov 9, 2021 at 12:34 AM Christoph Hellwig <hch@lst.de> wrote:
>
> Use the explicit DAX flag instead of checking the inode flag in the
> iomap code.

It's not immediately clear to me why this is a net benefit, are you
anticipating inode-less operations? With reflink and multi-inode
operations a single iomap flag seems insufficient, no?