From a437d774313a2faedaf9035ae817bede9fef7f3a Mon Sep 17 00:00:00 2001
From: Chris Lu <chris.lu@gmail.com>
Date: Mon, 2 Jun 2014 09:22:23 -0700
Subject: [PATCH] only set lookup cache when successful

---
 go/operation/lookup.go | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/go/operation/lookup.go b/go/operation/lookup.go
index 2eea1ab34..f191bfdbf 100644
--- a/go/operation/lookup.go
+++ b/go/operation/lookup.go
@@ -28,8 +28,9 @@ var (
 func Lookup(server string, vid string) (ret *LookupResult, err error) {
 	locations, cache_err := vc.Get(vid)
 	if cache_err != nil {
-		ret, err = do_lookup(server, vid)
-		vc.Set(vid, ret.Locations, 1*time.Minute)
+		if ret, err = do_lookup(server, vid); err == nil {
+			vc.Set(vid, ret.Locations, 1*time.Minute)
+		}
 	} else {
 		ret = &LookupResult{VolumeId: vid, Locations: locations}
 	}