xfs: provide a query_range function for freespace btrees

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>

2 files changed, 52 insertions, 0 deletions

diff --git a/fs/xfs/libxfs/xfs_alloc.c b/fs/xfs/libxfs/xfs_alloc.c
index 369adcc18c02..f65b8d49ec16 100644
--- a/fs/xfs/libxfs/xfs_alloc.c
+++ b/fs/xfs/libxfs/xfs_alloc.c
@@ -2868,3 +2868,45 @@ err:
         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 2a8d0fa6fbbe..6c2643c4abd3 100644
--- a/fs/xfs/libxfs/xfs_alloc.h
+++ b/fs/xfs/libxfs/xfs_alloc.h
@@ -219,4 +219,14 @@ 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__ */