From 93ca87b7cbf53e6b17a8a6d3b5dec32af94cd00c Mon Sep 17 00:00:00 2001
From: Konstantin Lebedev <9497591+kmlebedev@users.noreply.github.com>
Date: Thu, 21 Jul 2022 15:51:14 +0500
Subject: [PATCH] use safe onPeerUpdateDoneCns

---
 weed/server/master_server.go | 44 ++++++++++++++++++++++++++----------
 1 file changed, 32 insertions(+), 12 deletions(-)

diff --git a/weed/server/master_server.go b/weed/server/master_server.go
index 98fb6aab1..03a3f74d1 100644
--- a/weed/server/master_server.go
+++ b/weed/server/master_server.go
@@ -11,7 +11,6 @@ import (
 	"regexp"
 	"strings"
 	"sync"
-	"sync/atomic"
 	"time"
 
 	"github.com/chrislusf/seaweedfs/weed/cluster"
@@ -33,9 +32,10 @@ import (
 )
 
 const (
-	SequencerType         = "master.sequencer.type"
-	SequencerSnowflakeId  = "master.sequencer.sequencer_snowflake_id"
-	RaftServerRemovalTime = 72 * time.Minute
+	SequencerType                 = "master.sequencer.type"
+	SequencerSnowflakeId          = "master.sequencer.sequencer_snowflake_id"
+	RaftServerRemovalTime         = 72 * time.Minute
+	ResetRaftServerRemovalTimeMsg = "ResetRaftServerRemovalTime"
 )
 
 type MasterOption struct {
@@ -66,8 +66,8 @@ type MasterServer struct {
 
 	boundedLeaderChan chan int
 
-	onPeerUpdateDoneCn         chan string
-	onPeerUpdateGoroutineCount int32
+	onPeerUpdateDoneCns map[string]*chan string
+	onPeerUpdateLock    sync.RWMutex
 
 	// notifying clients
 	clientChansLock sync.RWMutex
@@ -119,9 +119,9 @@ func NewMasterServer(r *mux.Router, option *MasterOption, peers map[string]pb.Se
 		Cluster:         cluster.NewCluster(),
 	}
 	ms.boundedLeaderChan = make(chan int, 16)
-	ms.onPeerUpdateDoneCn = make(chan string)
 
 	ms.MasterClient.OnPeerUpdate = ms.OnPeerUpdate
+	ms.onPeerUpdateDoneCns = make(map[string]*chan string)
 
 	seq := ms.createSequencer(option)
 	if nil == seq {
@@ -367,16 +367,31 @@ func (ms *MasterServer) OnPeerUpdate(update *master_pb.ClusterNodeUpdate, startF
 					hashicorpRaft.ServerAddress(peerAddress.ToGrpcAddress()), 0, 0)
 			}
 		}
-		if atomic.LoadInt32(&ms.onPeerUpdateGoroutineCount) > 0 {
-			ms.onPeerUpdateDoneCn <- peerName
+		ms.onPeerUpdateLock.RLock()
+		if len(ms.onPeerUpdateDoneCns) > 0 {
+			for _, onPeerUpdateDoneCn := range ms.onPeerUpdateDoneCns {
+				*onPeerUpdateDoneCn <- peerName
+			}
 		}
+		ms.onPeerUpdateLock.RUnlock()
 	} else if isLeader {
+		if onPeerUpdateDoneCnPrev, ok := ms.onPeerUpdateDoneCns[peerName]; ok {
+			*onPeerUpdateDoneCnPrev <- ResetRaftServerRemovalTimeMsg
+			return
+		}
+		onPeerUpdateDoneCn := make(chan string)
+		ms.onPeerUpdateLock.Lock()
+		ms.onPeerUpdateDoneCns[peerName] = &onPeerUpdateDoneCn
+		ms.onPeerUpdateLock.Unlock()
+
 		go func(peerName string) {
 			raftServerRemovalTimeAfter := time.After(RaftServerRemovalTime)
 			raftServerPingTicker := time.NewTicker(5 * time.Minute)
-			atomic.AddInt32(&ms.onPeerUpdateGoroutineCount, 1)
 			defer func() {
-				atomic.AddInt32(&ms.onPeerUpdateGoroutineCount, -1)
+				ms.onPeerUpdateLock.Lock()
+				delete(ms.onPeerUpdateDoneCns, peerName)
+				ms.onPeerUpdateLock.Unlock()
+				close(onPeerUpdateDoneCn)
 			}()
 			for {
 				select {
@@ -408,11 +423,16 @@ func (ms *MasterServer) OnPeerUpdate(update *master_pb.ClusterNodeUpdate, startF
 					}
 					glog.V(0).Infof("old raft server %s removed", peerName)
 					return
-				case peerDone := <-ms.onPeerUpdateDoneCn:
+				case peerDone := <-onPeerUpdateDoneCn:
 					if peerName == peerDone {
 						glog.V(0).Infof("raft server %s remove canceled on onPeerUpdate", peerName)
 						return
 					}
+					if peerDone == ResetRaftServerRemovalTimeMsg {
+						raftServerRemovalTimeAfter = time.After(RaftServerRemovalTime)
+						glog.V(0).Infof("rest wait %v for raft server %s activity, otherwise delete",
+							RaftServerRemovalTime, peerName)
+					}
 				}
 			}
 		}(peerName)