Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Date:   Tue, 8 Oct 2019 23:31:44 -0700
From:   Christoph Hellwig <hch@infradead.org>
To:     Shiyang Ruan <ruansy.fnst@cn.fujitsu.com>
Cc:     linux-xfs@vger.kernel.org, linux-nvdimm@lists.01.org,
        darrick.wong@oracle.com, linux-kernel@vger.kernel.org,
        rgoldwyn@suse.de, gujx@cn.fujitsu.com, david@fromorbit.com,
        qi.fuli@fujitsu.com, caoj.fnst@cn.fujitsu.com
Subject: Re: [RFC PATCH 0/7] xfs: add reflink & dedupe support for fsdax.
Message-ID: <20191009063144.GA4300@infradead.org>
References: <20190731114935.11030-1-ruansy.fnst@cn.fujitsu.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20190731114935.11030-1-ruansy.fnst@cn.fujitsu.com>
User-Agent: Mutt/1.12.1 (2019-06-15)
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Btw, I just had a chat with Dan last week on this.  And he pointed out
that while this series deals with the read/write path issues of 
reflink on DAX it doesn't deal with the mmap side issue that
page->mapping and page->index can point back to exactly one file.

I think we want a few xfstests that reflink a file and then use the
different links using mmap, as that should blow up pretty reliably.