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Date: Thu, 14 Oct 2021 23:38:22 -0700
From: Christoph Hellwig <hch@infradead.org>
To: "Darrick J. Wong" <djwong@kernel.org>
Cc: Shiyang Ruan <ruansy.fnst@fujitsu.com>, linux-kernel@vger.kernel.org,
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	dan.j.williams@intel.com, david@fromorbit.com, hch@infradead.org,
	jane.chu@oracle.com
Subject: Re: [PATCH v7 8/8] fsdax: add exception for reflinked files
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On Thu, Oct 14, 2021 at 12:24:50PM -0700, Darrick J. Wong wrote:
> It feels a little dangerous to have page->mapping for shared storage
> point to an actual address_space when there are really multiple
> potential address_spaces out there.  If the mm or dax folks are ok with
> doing this this way then I'll live with it, but it seems like you'd want
> to leave /some/ kind of marker once you know that the page has multiple
> owners and therefore regular mm rmap via page->mapping won't work.

Yes, I thing poisoning page->mapping for the rmap enabled case seems
like a better idea.