Re: [PATCH 3/8] xfs: provide a query_range function for freespace btrees

[Brian Foster <bfoster@redhat.com>]

On Fri, Feb 17, 2017 at 05:17:36PM -0800, Darrick J. Wong wrote:
> From: Darrick J. Wong <darrick.wong@oracle.com>
> 
> Implement a query_range function for the bnobt and cntbt.  This will
> be used for getfsmap fallback if there is no rmapbt and by the online
> scrub and repair code.
> 
> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
> ---

Reviewed-by: Brian Foster <bfoster@redhat.com>

>  fs/xfs/libxfs/xfs_alloc.c |   42 ++++++++++++++++++++++++++++++++++++++++++
>  fs/xfs/libxfs/xfs_alloc.h |   10 ++++++++++
>  2 files changed, 52 insertions(+)
> 
> 
> diff --git a/fs/xfs/libxfs/xfs_alloc.c b/fs/xfs/libxfs/xfs_alloc.c
> index 9f06a21..526df17 100644
> --- a/fs/xfs/libxfs/xfs_alloc.c
> +++ b/fs/xfs/libxfs/xfs_alloc.c
> @@ -2875,3 +2875,45 @@ xfs_free_extent(
>  	xfs_trans_brelse(tp, agbp);
>  	return error;
>  }
> +
> +struct xfs_alloc_query_range_info {
> +	xfs_alloc_query_range_fn	fn;
> +	void				*priv;
> +};
> +
> +/* Format btree record and pass to our callback. */
> +STATIC int
> +xfs_alloc_query_range_helper(
> +	struct xfs_btree_cur		*cur,
> +	union xfs_btree_rec		*rec,
> +	void				*priv)
> +{
> +	struct xfs_alloc_query_range_info	*query = priv;
> +	struct xfs_alloc_rec_incore		irec;
> +
> +	irec.ar_startblock = be32_to_cpu(rec->alloc.ar_startblock);
> +	irec.ar_blockcount = be32_to_cpu(rec->alloc.ar_blockcount);
> +	return query->fn(cur, &irec, query->priv);
> +}
> +
> +/* Find all free space within a given range of blocks. */
> +int
> +xfs_alloc_query_range(
> +	struct xfs_btree_cur			*cur,
> +	struct xfs_alloc_rec_incore		*low_rec,
> +	struct xfs_alloc_rec_incore		*high_rec,
> +	xfs_alloc_query_range_fn		fn,
> +	void					*priv)
> +{
> +	union xfs_btree_irec			low_brec;
> +	union xfs_btree_irec			high_brec;
> +	struct xfs_alloc_query_range_info	query;
> +
> +	ASSERT(cur->bc_btnum == XFS_BTNUM_BNO);
> +	low_brec.a = *low_rec;
> +	high_brec.a = *high_rec;
> +	query.priv = priv;
> +	query.fn = fn;
> +	return xfs_btree_query_range(cur, &low_brec, &high_brec,
> +			xfs_alloc_query_range_helper, &query);
> +}
> diff --git a/fs/xfs/libxfs/xfs_alloc.h b/fs/xfs/libxfs/xfs_alloc.h
> index 1d0f48a..f534998 100644
> --- a/fs/xfs/libxfs/xfs_alloc.h
> +++ b/fs/xfs/libxfs/xfs_alloc.h
> @@ -223,4 +223,14 @@ int xfs_free_extent_fix_freelist(struct xfs_trans *tp, xfs_agnumber_t agno,
>  
>  xfs_extlen_t xfs_prealloc_blocks(struct xfs_mount *mp);
>  
> +typedef int (*xfs_alloc_query_range_fn)(
> +	struct xfs_btree_cur		*cur,
> +	struct xfs_alloc_rec_incore	*rec,
> +	void				*priv);
> +
> +int xfs_alloc_query_range(struct xfs_btree_cur *cur,
> +		struct xfs_alloc_rec_incore *low_rec,
> +		struct xfs_alloc_rec_incore *high_rec,
> +		xfs_alloc_query_range_fn fn, void *priv);
> +
>  #endif	/* __XFS_ALLOC_H__ */
> 
> --
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