[PATCH 040/119] xfs: create helpers for mapping, unmapping, and converting file fork extents

[Brian Foster]

On Thu, Jun 16, 2016 at 06:22:08PM -0700, Darrick J. Wong wrote:
> Create two helper functions to assist with mapping, unmapping, and
> converting flag status of extents in a file's data/attr forks.  For
> non-shared files we can use the _alloc, _free, and _convert functions;
> when reflink comes these functions will be augmented to deal with
> shared extents.
> 
> Signed-off-by: Darrick J. Wong <darrick.wong at oracle.com>
> ---
>  fs/xfs/libxfs/xfs_rmap.c |   42 ++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 42 insertions(+)
> 
> 
> diff --git a/fs/xfs/libxfs/xfs_rmap.c b/fs/xfs/libxfs/xfs_rmap.c
> index f92eaa1..76fc5c2 100644
> --- a/fs/xfs/libxfs/xfs_rmap.c
> +++ b/fs/xfs/libxfs/xfs_rmap.c
> @@ -1123,11 +1123,53 @@ done:
>  	return error;
>  }
>  
> +/*
> + * Convert an unwritten extent to a real extent or vice versa.
> + */
> +STATIC int
> +xfs_rmap_convert(
> +	struct xfs_btree_cur	*cur,
> +	xfs_agblock_t		bno,
> +	xfs_extlen_t		len,
> +	bool			unwritten,
> +	struct xfs_owner_info	*oinfo)
> +{
> +	return __xfs_rmap_convert(cur, bno, len, unwritten, oinfo);
> +}
> +

Hmm, these all look like 1-1 mappings and they're static as well. Is the
additional interface for reflink? If so, I think it might be better to
punt this down to where it is really used (reflink).

Brian

>  #undef	NEW
>  #undef	LEFT
>  #undef	RIGHT
>  #undef	PREV
>  
> +/*
> + * Find an extent in the rmap btree and unmap it.
> + */
> +STATIC int
> +xfs_rmap_unmap(
> +	struct xfs_btree_cur	*cur,
> +	xfs_agblock_t		bno,
> +	xfs_extlen_t		len,
> +	bool			unwritten,
> +	struct xfs_owner_info	*oinfo)
> +{
> +	return __xfs_rmap_free(cur, bno, len, unwritten, oinfo);
> +}
> +
> +/*
> + * Find an extent in the rmap btree and map it.
> + */
> +STATIC int
> +xfs_rmap_map(
> +	struct xfs_btree_cur	*cur,
> +	xfs_agblock_t		bno,
> +	xfs_extlen_t		len,
> +	bool			unwritten,
> +	struct xfs_owner_info	*oinfo)
> +{
> +	return __xfs_rmap_alloc(cur, bno, len, unwritten, oinfo);
> +}
> +
>  struct xfs_rmapbt_query_range_info {
>  	xfs_rmapbt_query_range_fn	fn;
>  	void				*priv;
> 
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