From 101e784577f9ebdc38d530b64c92e09da76e11be Mon Sep 17 00:00:00 2001
From: Chris Lu <chris.lu@gmail.com>
Date: Thu, 23 Jun 2016 09:10:25 -0700
Subject: [PATCH] add locking on possible concurrent map access

fix https://github.com/chrislusf/seaweedfs/issues/328
---
 weed/storage/compact_map.go | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/weed/storage/compact_map.go b/weed/storage/compact_map.go
index d4438d044..6afaf7df8 100644
--- a/weed/storage/compact_map.go
+++ b/weed/storage/compact_map.go
@@ -190,18 +190,22 @@ func (cm *CompactMap) binarySearchCompactSection(key Key) int {
 // Visit visits all entries or stop if any error when visiting
 func (cm *CompactMap) Visit(visit func(NeedleValue) error) error {
 	for _, cs := range cm.list {
+		cs.RLock()
 		for _, v := range cs.overflow {
 			if err := visit(v); err != nil {
+				cs.RUnlock()
 				return err
 			}
 		}
 		for _, v := range cs.values {
 			if _, found := cs.overflow[v.Key]; !found {
 				if err := visit(v); err != nil {
+					cs.RUnlock()
 					return err
 				}
 			}
 		}
+		cs.RUnlock()
 	}
 	return nil
 }