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References: <20220410160904.3758789-1-ruansy.fnst@fujitsu.com> <20220410160904.3758789-2-ruansy.fnst@fujitsu.com>
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From:   Dan Williams <dan.j.williams@intel.com>
Date:   Tue, 12 Apr 2022 16:22:34 -0700
Message-ID: <CAPcyv4iqHMR4Pee0Mjca2iM6Vhht8s=56-ZefYvpBmxuEi0Q6A@mail.gmail.com>
Subject: Re: [PATCH v12 1/7] dax: Introduce holder for dax_device
To:     Shiyang Ruan <ruansy.fnst@fujitsu.com>
Cc:     Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        linux-xfs <linux-xfs@vger.kernel.org>,
        Linux NVDIMM <nvdimm@lists.linux.dev>,
        Linux MM <linux-mm@kvack.org>,
        linux-fsdevel <linux-fsdevel@vger.kernel.org>,
        "Darrick J. Wong" <djwong@kernel.org>, david <david@fromorbit.com>,
        Christoph Hellwig <hch@infradead.org>,
        Jane Chu <jane.chu@oracle.com>
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On Sun, Apr 10, 2022 at 9:09 AM Shiyang Ruan <ruansy.fnst@fujitsu.com> wrote:
>
> To easily track filesystem from a pmem device, we introduce a holder for
> dax_device structure, and also its operation.  This holder is used to
> remember who is using this dax_device:
>  - When it is the backend of a filesystem, the holder will be the
>    instance of this filesystem.
>  - When this pmem device is one of the targets in a mapped device, the
>    holder will be this mapped device.  In this case, the mapped device
>    has its own dax_device and it will follow the first rule.  So that we
>    can finally track to the filesystem we needed.
>
> The holder and holder_ops will be set when filesystem is being mounted,
> or an target device is being activated.
>

Looks good to me:

Reviewed-by: Dan Williams <dan.j.wiliams@intel.com>

I am assuming this will be staged in a common DAX branch, but holler
now if this should go through the XFS tree.