diff --git a/persistent-data/space-maps/recursive.cc b/persistent-data/space-maps/recursive.cc
index dadbe88..0977e61 100644
--- a/persistent-data/space-maps/recursive.cc
+++ b/persistent-data/space-maps/recursive.cc
@@ -97,6 +97,12 @@ namespace {
 				add_op(b, block_op(SET, c));
 			else {
 				recursing_lock lock(*this);
+
+				// the inner set_count may trigger a find_free,
+				// so it's important we update the allocated
+				// blocks list before calling.
+				allocated_blocks_.add(b, b + 1);
+
 				return sm_->set_count(b, c);
 			}
 		}
@@ -111,6 +117,12 @@ namespace {
 				add_op(b, block_op(INC, count));
 			else {
 				recursing_lock lock(*this);
+
+				// the inner inc() may trigger a find_free,
+				// so it's important we update the allocated
+				// blocks list before calling.
+				allocated_blocks_.add(b, b + 1);
+
 				return sm_->inc(b, count);
 			}
 		}