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References: <20210604011844.1756145-1-ruansy.fnst@fujitsu.com> <20210604011844.1756145-4-ruansy.fnst@fujitsu.com>
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From:   Dan Williams <dan.j.williams@intel.com>
Date:   Tue, 15 Jun 2021 17:48:49 -0700
Message-ID: <CAPcyv4h=bUCgFudKTrW09dzi8MWxg7cBC9m68zX1=HY24ftR-A@mail.gmail.com>
Subject: Re: [PATCH v4 03/10] fs: Introduce ->corrupted_range() for superblock
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 MM <linux-mm@kvack.org>,
        linux-fsdevel <linux-fsdevel@vger.kernel.org>,
        device-mapper development <dm-devel@redhat.com>,
        "Darrick J. Wong" <darrick.wong@oracle.com>,
        david <david@fromorbit.com>, Christoph Hellwig <hch@lst.de>,
        Alasdair Kergon <agk@redhat.com>,
        Mike Snitzer <snitzer@redhat.com>,
        Goldwyn Rodrigues <rgoldwyn@suse.de>,
        Linux NVDIMM <nvdimm@lists.linux.dev>
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[ drop old linux-nvdimm@lists.01.org, add nvdimm@lists.linux.dev ]

On Thu, Jun 3, 2021 at 6:19 PM Shiyang Ruan <ruansy.fnst@fujitsu.com> wrote:
>
> Memory failure occurs in fsdax mode will finally be handled in
> filesystem.  We introduce this interface to find out files or metadata
> affected by the corrupted range, and try to recover the corrupted data
> if possiable.
>
> Signed-off-by: Shiyang Ruan <ruansy.fnst@fujitsu.com>
> ---
>  include/linux/fs.h | 2 ++
>  1 file changed, 2 insertions(+)
>
> diff --git a/include/linux/fs.h b/include/linux/fs.h
> index c3c88fdb9b2a..92af36c4225f 100644
> --- a/include/linux/fs.h
> +++ b/include/linux/fs.h
> @@ -2176,6 +2176,8 @@ struct super_operations {
>                                   struct shrink_control *);
>         long (*free_cached_objects)(struct super_block *,
>                                     struct shrink_control *);
> +       int (*corrupted_range)(struct super_block *sb, struct block_device *bdev,
> +                              loff_t offset, size_t len, void *data);

Why does the superblock need a new operation? Wouldn't whatever
function is specified here just be specified to the dax_dev as the
->notify_failure() holder callback?