From 2203600e0523c70815d69512a5c00a2e5a0d5b2a Mon Sep 17 00:00:00 2001
From: Jon Siwek <jsiwek@illinois.edu>
Date: Wed, 25 Sep 2013 12:04:07 -0500
Subject: [PATCH] Fix logic for failed DNS TXT lookups.

A failed request should not evict a previous result from the local
cache/mapping.
---
 src/DNS_Mgr.cc | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/src/DNS_Mgr.cc b/src/DNS_Mgr.cc
index 5880a02c57..08e8889a10 100644
--- a/src/DNS_Mgr.cc
+++ b/src/DNS_Mgr.cc
@@ -711,17 +711,19 @@ void DNS_Mgr::AddResult(DNS_Mgr_Request* dr, struct nb_dns_result* r)
 		if ( dr->ReqIsTxt() )
 			{
 			TextMap::iterator it = text_mappings.find(dr->ReqHost());
+
 			if ( it == text_mappings.end() )
 				text_mappings[dr->ReqHost()] = new_dm;
 			else
 				{
-				if ( new_dm->Failed() && prev_dm && prev_dm->Valid() )
-					++keep_prev;
-				else
-					{
-					prev_dm = it->second;
-					it->second = new_dm;
-					}
+				prev_dm = it->second;
+				it->second = new_dm;
+				}
+
+			if ( new_dm->Failed() && prev_dm && prev_dm->Valid() )
+				{
+				text_mappings[dr->ReqHost()] = prev_dm;
+				++keep_prev;
 				}
 			}
 		else