Re: [PATCH 034/119] xfs: teach rmapbt to support interval queries

Brian Foster
2016-07-08T18:34:07Z

On Thu, Jun 16, 2016 at 06:21:30PM -0700, Darrick J. Wong wrote:
> Now that the generic btree code supports querying all records within a
> range of keys, use that functionality to allow us to ask for all the
> extents mapped to a range of physical blocks.
>
> v2: Move unwritten bit to rm_offset.
>
> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
> ---
> fs/xfs/libxfs/xfs_rmap.c | 43 ++++++++++++++++++++++++++++++++++++++++
> fs/xfs/libxfs/xfs_rmap_btree.h | 9 ++++++++
> 2 files changed, 52 insertions(+)
>
>
> diff --git a/fs/xfs/libxfs/xfs_rmap.c b/fs/xfs/libxfs/xfs_rmap.c
> index c6a5a0b..0e1721a 100644
> --- a/fs/xfs/libxfs/xfs_rmap.c
> +++ b/fs/xfs/libxfs/xfs_rmap.c
> @@ -184,3 +184,46 @@ out_error:
> trace_xfs_rmap_alloc_extent_error(mp, agno, bno, len, false, oinfo);
> return error;
> }
> +
> +struct xfs_rmapbt_query_range_info {
> + xfs_rmapbt_query_range_fn fn;
> + void *priv;
> +};
> +
> +/* Format btree record and pass to our callback. */
> +STATIC int
> +xfs_rmapbt_query_range_helper(
> + struct xfs_btree_cur *cur,
> + union xfs_btree_rec *rec,
> + void *priv)
> +{
> + struct xfs_rmapbt_query_range_info *query = priv;
> + struct xfs_rmap_irec irec;
> + int error;
> +
> + error = xfs_rmapbt_btrec_to_irec(rec, &irec);
> + if (error)
> + return error;
> + return query->fn(cur, &irec, query->priv);
> +}
> +
> +/* Find all rmaps between two keys. */
> +int
> +xfs_rmapbt_query_range(
> + struct xfs_btree_cur *cur,
> + struct xfs_rmap_irec *low_rec,
> + struct xfs_rmap_irec *high_rec,
> + xfs_rmapbt_query_range_fn fn,
> + void *priv)
> +{
> + union xfs_btree_irec low_brec;
> + union xfs_btree_irec high_brec;
> + struct xfs_rmapbt_query_range_info query;
> +
> + low_brec.r = *low_rec;
> + high_brec.r = *high_rec;

Some checks or asserts that these are actually in order couldn't hurt.
Otherwise looks good:

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

> + query.priv = priv;
> + query.fn = fn;
> + return xfs_btree_query_range(cur, &low_brec, &high_brec,
> + xfs_rmapbt_query_range_helper, &query);
> +}
> diff --git a/fs/xfs/libxfs/xfs_rmap_btree.h b/fs/xfs/libxfs/xfs_rmap_btree.h
> index 796071c..e926c6e 100644
> --- a/fs/xfs/libxfs/xfs_rmap_btree.h
> +++ b/fs/xfs/libxfs/xfs_rmap_btree.h
> @@ -74,4 +74,13 @@ int xfs_rmap_free(struct xfs_trans *tp, struct xfs_buf *agbp,
> xfs_agnumber_t agno, xfs_agblock_t bno, xfs_extlen_t len,
> struct xfs_owner_info *oinfo);
>
> +typedef int (*xfs_rmapbt_query_range_fn)(
> + struct xfs_btree_cur *cur,
> + struct xfs_rmap_irec *rec,
> + void *priv);
> +
> +int xfs_rmapbt_query_range(struct xfs_btree_cur *cur,
> + struct xfs_rmap_irec *low_rec, struct xfs_rmap_irec *high_rec,
> + xfs_rmapbt_query_range_fn fn, void *priv);
> +
> #endif /* __XFS_RMAP_BTREE_H__ */
>
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