From mboxrd@z Thu Jan  1 00:00:00 1970
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Date: Wed, 17 Oct 2018 01:40:02 -0700
From: Christoph Hellwig <hch@infradead.org>
To: "Darrick J. Wong" <darrick.wong@oracle.com>
Cc: david@fromorbit.com, sandeen@redhat.com, linux-nfs@vger.kernel.org,
	linux-cifs@vger.kernel.org, linux-unionfs@vger.kernel.org,
	linux-xfs@vger.kernel.org, linux-mm@kvack.org,
	linux-btrfs@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	ocfs2-devel@oss.oracle.com
Subject: Re: [PATCH 25/26] xfs: support returning partial reflink results
Message-ID: <20181017084002.GI16896@infradead.org>
References: <153965939489.1256.7400115244528045860.stgit@magnolia>
 <153966005536.3607.787445581785795364.stgit@magnolia>
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List-ID: <linux-fsdevel.vger.kernel.org>

> @@ -1415,11 +1419,17 @@ xfs_reflink_remap_range(
>  
>  	trace_xfs_reflink_remap_range(src, pos_in, len, dest, pos_out);
>  
> +	if (len == 0) {
> +		ret = 0;
> +		goto out_unlock;
> +	}
> +

As pointed out last time this check is superflous, right above we have
this check:

	if (ret < 0 || len == 0)
		return ret;

>  	ret = xfs_reflink_remap_blocks(src, sfsbno, dest, dfsbno, fsblen,
> -			pos_out + len);
> +			&remappedfsb, pos_out + len);
> +	remapped_bytes = min_t(loff_t, len, XFS_FSB_TO_B(mp, remappedfsb));

I still think returning the bytes from the function would be saner,
but maybe that's just me.