dm persistent data: add btree_walk

[karo-tx-linux.git] / drivers / md / persistent-data / dm-btree.c

diff --git a/drivers/md/persistent-data/dm-btree.c b/drivers/md/persistent-data/dm-btree.c
index 4caf66918cdb35249544fdf296dd07d2594ae63a..35865425e4b4443e925014fd918655ef51c07d57 100644 (file)
--- a/drivers/md/persistent-data/dm-btree.c
+++ b/drivers/md/persistent-data/dm-btree.c
@@ -807,3 +807,55 @@ int dm_btree_find_highest_key(struct dm_btree_info *info, dm_block_t root,
        return r ? r : count;
 }
 EXPORT_SYMBOL_GPL(dm_btree_find_highest_key);
+
+/*
+ * FIXME: We shouldn't use a recursive algorithm when we have limited stack
+ * space.  Also this only works for single level trees.
+ */
+static int walk_node(struct ro_spine *s, dm_block_t block,
+                    int (*fn)(void *context, uint64_t *keys, void *leaf),
+                    void *context)
+{
+       int r;
+       unsigned i, nr;
+       struct btree_node *n;
+       uint64_t keys;
+
+       r = ro_step(s, block);
+       n = ro_node(s);
+
+       nr = le32_to_cpu(n->header.nr_entries);
+       for (i = 0; i < nr; i++) {
+               if (le32_to_cpu(n->header.flags) & INTERNAL_NODE) {
+                       r = walk_node(s, value64(n, i), fn, context);
+                       if (r)
+                               goto out;
+               } else {
+                       keys = le64_to_cpu(*key_ptr(n, i));
+                       r = fn(context, &keys, value_ptr(n, i));
+                       if (r)
+                               goto out;
+               }
+       }
+
+out:
+       ro_pop(s);
+       return r;
+}
+
+int dm_btree_walk(struct dm_btree_info *info, dm_block_t root,
+                 int (*fn)(void *context, uint64_t *keys, void *leaf),
+                 void *context)
+{
+       int r;
+       struct ro_spine spine;
+
+       BUG_ON(info->levels > 1);
+
+       init_ro_spine(&spine, info);
+       r = walk_node(&spine, root, fn, context);
+       exit_ro_spine(&spine);
+
+       return r;
+}
+EXPORT_SYMBOL_GPL(dm_btree_walk);