lazyfree: fix memory leak for lazyfree-lazy-server-del

src/lazyfree.c

@@ -64,9 +64,10 @@ int dbAsyncDelete(redisDb *db, robj *key) {
         robj *val = dictGetVal(de);
         size_t free_effort = lazyfreeGetFreeEffort(val);
 
-        /* If releasing the object is too much work, let's put it into the
-         * lazy free list. */
-        if (free_effort > LAZYFREE_THRESHOLD) {
+        /* If releasing the object is too much work and the refcount
+         * is 1, that means the object really needs to be freed,
+         * let's put it into the lazy free list. */
+        if (free_effort > LAZYFREE_THRESHOLD && val->refcount == 1) {
             atomicIncr(lazyfree_objects,1);
             bioCreateBackgroundJob(BIO_LAZY_FREE,val,NULL,NULL);
             dictSetVal(db->dict,de,NULL);