diff --git a/persistent-data/data-structures/btree_damage_visitor.cc b/persistent-data/data-structures/btree_damage_visitor.cc
new file mode 100644
index 0000000..d6a6dee
--- /dev/null
+++ b/persistent-data/data-structures/btree_damage_visitor.cc
@@ -0,0 +1,56 @@
+#include "persistent-data/data-structures/btree_damage_visitor.h"
+
+using namespace persistent_data;
+
+//----------------------------------------------------------------
+
+damage_tracker::damage_tracker()
+	: damaged_(false),
+	  damage_begin_(0)
+{
+}
+
+void
+damage_tracker::bad_node()
+{
+	damaged_ = true;
+}
+
+maybe_range64
+damage_tracker::good_internal(block_address begin)
+{
+	maybe_range64 r;
+
+	if (damaged_) {
+		r = maybe_range64(range64(damage_begin_, begin));
+		damaged_ = false;
+	}
+
+	damage_begin_ = begin;
+	return r;
+}
+
+maybe_range64
+damage_tracker::good_leaf(uint64_t begin, uint64_t end)
+{
+	maybe_range64 r;
+
+	if (damaged_) {
+		r = maybe_range64(range64(damage_begin_, begin));
+		damaged_ = false;
+	}
+
+	damage_begin_ = end;
+	return r;
+}
+
+maybe_range64
+damage_tracker::end()
+{
+	if (damaged_)
+		return maybe_range64(damage_begin_);
+	else
+		return maybe_range64();
+}
+
+//----------------------------------------------------------------