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Date:   Thu, 30 Jun 2022 17:31:19 -0700
From:   "Darrick J. Wong" <djwong@kernel.org>
To:     Shiyang Ruan <ruansy.fnst@fujitsu.com>
Cc:     linux-kernel@vger.kernel.org, linux-xfs@vger.kernel.org,
        nvdimm@lists.linux.dev, linux-fsdevel@vger.kernel.org,
        david@fromorbit.com, hch@infradead.org
Subject: Re: [PATCH] xfs: fail dax mount if reflink is enabled on a partition
Message-ID: <Yr5AV5HaleJXMmUm@magnolia>
References: <20220609143435.393724-1-ruansy.fnst@fujitsu.com>
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On Thu, Jun 09, 2022 at 10:34:35PM +0800, Shiyang Ruan wrote:
> Failure notification is not supported on partitions.  So, when we mount
> a reflink enabled xfs on a partition with dax option, let it fail with
> -EINVAL code.
> 
> Signed-off-by: Shiyang Ruan <ruansy.fnst@fujitsu.com>

Looks good to me, though I think this patch applies to ... wherever all
those rmap+reflink+dax patches went.  I think that's akpm's tree, right?

Ideally this would go in through there to keep the pieces together, but
I don't mind tossing this in at the end of the 5.20 merge window if akpm
is unwilling.

Reviewed-by: Darrick J. Wong <djwong@kernel.org>

--D

> ---
>  fs/xfs/xfs_super.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
> index 8495ef076ffc..a3c221841fa6 100644
> --- a/fs/xfs/xfs_super.c
> +++ b/fs/xfs/xfs_super.c
> @@ -348,8 +348,10 @@ xfs_setup_dax_always(
>  		goto disable_dax;
>  	}
>  
> -	if (xfs_has_reflink(mp)) {
> -		xfs_alert(mp, "DAX and reflink cannot be used together!");
> +	if (xfs_has_reflink(mp) &&
> +	    bdev_is_partition(mp->m_ddev_targp->bt_bdev)) {
> +		xfs_alert(mp,
> +			"DAX and reflink cannot work with multi-partitions!");
>  		return -EINVAL;
>  	}
>  
> -- 
> 2.36.1
> 
> 
>