diff --git a/daemon/name_cache.c b/daemon/name_cache.c
index 3d55ddf..fa4b2b1 100644
--- a/daemon/name_cache.c
+++ b/daemon/name_cache.c
@@ -38,11 +38,21 @@ enum {
     NCLVL2
 };
 
+
 #define NAME_CACHE_EXPIRATION 20 /* TODO: get from configuration */
 
 /* allow up to 128K of memory for name and attribute cache entries */
 #define NAME_CACHE_MAX_SIZE 131072
 
+/* negative lookup caching
+ *
+ * by caching lookups that result in NOENT, we can avoid sending subsequent
+ * lookups over the wire.  a name cache entry is negative when its attributes
+ * pointer is NULL.  negative entries are created by three functions:
+ * nfs41_name_cache_remove(), _insert() when called with NULL for the fh and
+ * attributes, and _rename() for the source entry
+ */
+
 
 /* attribute cache */
 struct attr_cache_entry {