diff --git a/extent-cache.c b/extent-cache.c
index 7656ab25..d80aead6 100644
--- a/extent-cache.c
+++ b/extent-cache.c
@@ -230,6 +230,15 @@ struct cache_extent *first_cache_extent(struct cache_tree *tree)
 	return rb_entry(node, struct cache_extent, rb_node);
 }
 
+struct cache_extent *last_cache_extent(struct cache_tree *tree)
+{
+	struct rb_node *node = rb_last(&tree->root);
+
+	if (!node)
+		return NULL;
+	return rb_entry(node, struct cache_extent, rb_node);
+}
+
 struct cache_extent *prev_cache_extent(struct cache_extent *pe)
 {
 	struct rb_node *node = rb_prev(&pe->rb_node);
diff --git a/extent-cache.h b/extent-cache.h
index cba83d15..a9d07e18 100644
--- a/extent-cache.h
+++ b/extent-cache.h
@@ -41,6 +41,7 @@ struct cache_extent {
 void cache_tree_init(struct cache_tree *tree);
 
 struct cache_extent *first_cache_extent(struct cache_tree *tree);
+struct cache_extent *last_cache_extent(struct cache_tree *tree);
 struct cache_extent *prev_cache_extent(struct cache_extent *pe);
 struct cache_extent *next_cache_extent(struct cache_extent *pe);