minor changes to doc and comments

src/db.c

@@ -19,7 +19,7 @@ robj *lookupKey(redisDb *db, robj *key) {
 
         if (server.ds_enabled && val->storage == REDIS_DS_SAVING) {
             /* FIXME: change this code to just wait for our object to
-             * get out of the IO Job. */
+             * get out of the IO Job. As it is now it is correct but slow. */
             waitEmptyIOJobsQueue();
             processAllPendingIOJobs();
             redisAssert(val->storage != REDIS_DS_SAVING);

src/dscache.c

@@ -109,6 +109,8 @@
  *   Also, make sure that key preloading is ONLY done for keys that are
  *   not marked as cacheKeyDoesNotExist(), otherwise, again, we can load
  *   data from disk that should instead be deleted.
+ *
+ * - dsSet() use rename(2) in order to avoid corruptions.
  */
 
 /* Virtual Memory is composed mainly of two subsystems: