From 66bcd6aa343f29e9b4addcfcb9934af15a24a432 Mon Sep 17 00:00:00 2001
From: Jimmy Hu <jimmy.hu@dexon.org>
Date: Sat, 3 Nov 2018 16:02:33 +0800
Subject: core: Fix fork vote (#290)

---
 core/agreement-state.go |  2 +-
 core/agreement.go       | 24 +++++++++++++-----------
 core/consensus.go       |  8 ++++----
 3 files changed, 18 insertions(+), 16 deletions(-)

diff --git a/core/agreement-state.go b/core/agreement-state.go
index 77569d5..fe329f8 100644
--- a/core/agreement-state.go
+++ b/core/agreement-state.go
@@ -118,9 +118,9 @@ func newCommitState(a *agreementData) *commitState {
 func (s *commitState) state() agreementStateType { return stateCommit }
 func (s *commitState) clocks() int               { return 2 }
 func (s *commitState) nextState() (agreementState, error) {
-	hash, ok := s.a.countVote(s.a.period, types.VotePreCom)
 	s.a.lock.Lock()
 	defer s.a.lock.Unlock()
+	hash, ok := s.a.countVoteNoLock(s.a.period, types.VotePreCom)
 	if ok && hash != skipBlockHash {
 		s.a.lockValue = hash
 		s.a.lockRound = s.a.period
diff --git a/core/agreement.go b/core/agreement.go
index d6875bc..b922cae 100644
--- a/core/agreement.go
+++ b/core/agreement.go
@@ -21,6 +21,7 @@ import (
 	"fmt"
 	"math"
 	"sync"
+	"sync/atomic"
 	"time"
 
 	"github.com/dexon-foundation/dexon-consensus/common"
@@ -103,7 +104,7 @@ type agreementData struct {
 type agreement struct {
 	state          agreementState
 	data           *agreementData
-	aID            types.Position
+	aID            *atomic.Value
 	notarySet      map[types.NodeID]struct{}
 	hasOutput      bool
 	lock           sync.RWMutex
@@ -126,6 +127,7 @@ func newAgreement(
 			ID:     ID,
 			leader: leader,
 		},
+		aID:            &atomic.Value{},
 		candidateBlock: make(map[common.Hash]*types.Block),
 		fastForward:    make(chan uint64, 1),
 		authModule:     authModule,
@@ -158,7 +160,7 @@ func (a *agreement) restart(
 		a.state = newInitialState(a.data)
 		a.notarySet = notarySet
 		a.candidateBlock = make(map[common.Hash]*types.Block)
-		a.aID = *aID.Clone()
+		a.aID.Store(aID)
 	}()
 
 	if isStop(aID) {
@@ -231,9 +233,7 @@ func (a *agreement) pullVotes() bool {
 
 // agreementID returns the current agreementID.
 func (a *agreement) agreementID() types.Position {
-	a.lock.RLock()
-	defer a.lock.RUnlock()
-	return a.aID
+	return a.aID.Load().(types.Position)
 }
 
 // nextState is called at the specific clock time.
@@ -288,10 +288,11 @@ func (a *agreement) processVote(vote *types.Vote) error {
 	if err := a.sanityCheck(vote); err != nil {
 		return err
 	}
-	if vote.Position != a.aID {
+	aID := a.agreementID()
+	if vote.Position != aID {
 		// Agreement module has stopped.
-		if !isStop(a.aID) {
-			if a.aID.Newer(&vote.Position) {
+		if !isStop(aID) {
+			if aID.Newer(&vote.Position) {
 				return nil
 			}
 		}
@@ -403,10 +404,11 @@ func (a *agreement) processBlock(block *types.Block) error {
 	a.data.blocksLock.Lock()
 	defer a.data.blocksLock.Unlock()
 
-	if block.Position != a.aID {
+	aID := a.agreementID()
+	if block.Position != aID {
 		// Agreement module has stopped.
-		if !isStop(a.aID) {
-			if a.aID.Newer(&block.Position) {
+		if !isStop(aID) {
+			if aID.Newer(&block.Position) {
 				return nil
 			}
 		}
diff --git a/core/consensus.go b/core/consensus.go
index 29d4aa2..c781de1 100644
--- a/core/consensus.go
+++ b/core/consensus.go
@@ -71,11 +71,11 @@ type consensusBAReceiver struct {
 }
 
 func (recv *consensusBAReceiver) ProposeVote(vote *types.Vote) {
+	if err := recv.agreementModule.prepareVote(vote); err != nil {
+		recv.consensus.logger.Error("Failed to prepare vote", "error", err)
+		return
+	}
 	go func() {
-		if err := recv.agreementModule.prepareVote(vote); err != nil {
-			recv.consensus.logger.Error("Failed to prepare vote", "error", err)
-			return
-		}
 		if err := recv.agreementModule.processVote(vote); err != nil {
 			recv.consensus.logger.Error("Failed to process vote", "error", err)
 			return
-- 
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