Fix datarace when stopping a node. (#723)

_assets/patches/geth/0016-fix-leveldb-issue.patch

@@ -1,5 +1,91 @@
+diff --git a/eth/downloader/downloader.go b/eth/downloader/downloader.go
+index 7ede530a9..60ff8dbc6 100644
+--- a/eth/downloader/downloader.go
++++ b/eth/downloader/downloader.go
+@@ -141,6 +141,8 @@ type Downloader struct {
+ 	quitCh   chan struct{} // Quit channel to signal termination
+ 	quitLock sync.RWMutex  // Lock to prevent double closes
+
++	downloads sync.WaitGroup // Keeps track of the currently active downloads
++
+ 	// Testing hooks
+ 	syncInitHook     func(uint64, uint64)  // Method to call upon initiating a new sync run
+ 	bodyFetchHook    func([]*types.Header) // Method to call upon starting a block body fetch
+@@ -398,7 +400,9 @@ func (d *Downloader) synchronise(id string, hash common.Hash, td *big.Int, mode
+ // specified peer and head hash.
+ func (d *Downloader) syncWithPeer(p *peerConnection, hash common.Hash, td *big.Int) (err error) {
+ 	d.mux.Post(StartEvent{})
++	d.downloads.Add(1)
+ 	defer func() {
++		d.downloads.Done()
+ 		// reset on error
+ 		if err != nil {
+ 			d.mux.Post(FailedEvent{err})
+@@ -528,6 +532,10 @@ func (d *Downloader) Terminate() {
+
+ 	// Cancel any pending download requests
+ 	d.Cancel()
++
++	// Wait, so external dependencies aren't destroyed
++	// until the download processing is done.
++	d.downloads.Wait()
+ }
+
+ // fetchHeight retrieves the head header of the remote peer to aid in estimating
+diff --git a/eth/handler.go b/eth/handler.go
+index c2426544f..08818a507 100644
+--- a/eth/handler.go
++++ b/eth/handler.go
+@@ -230,6 +230,9 @@ func (pm *ProtocolManager) Stop() {
+ 	// Quit fetcher, txsyncLoop.
+ 	close(pm.quitSync)
+
++	// Stop downloader and make sure that all the running downloads are complete.
++	pm.downloader.Terminate()
++
+ 	// Disconnect existing sessions.
+ 	// This also closes the gate for any new registrations on the peer set.
+ 	// sessions which are already established but not added to pm.peers yet
+diff --git a/eth/sync.go b/eth/sync.go
+index 2da1464bc..f14e84303 100644
+--- a/eth/sync.go
++++ b/eth/sync.go
+@@ -135,7 +135,6 @@ func (pm *ProtocolManager) syncer() {
+ 	// Start and ensure cleanup of sync mechanisms
+ 	pm.fetcher.Start()
+ 	defer pm.fetcher.Stop()
+-	defer pm.downloader.Terminate()
+
+ 	// Wait for different events to fire synchronisation operations
+ 	forceSync := time.NewTicker(forceSyncCycle)
+diff --git a/les/handler.go b/les/handler.go
+index 864abe605..67e459594 100644
+--- a/les/handler.go
++++ b/les/handler.go
+@@ -241,6 +241,9 @@ func (pm *ProtocolManager) Stop() {
+
+ 	close(pm.quitSync) // quits syncer, fetcher
+
++	// Stop downloader and make sure that all the running downloads are complete.
++	pm.downloader.Terminate()
++
+ 	// Disconnect existing sessions.
+ 	// This also closes the gate for any new registrations on the peer set.
+ 	// sessions which are already established but not added to pm.peers yet
+diff --git a/les/sync.go b/les/sync.go
+index c0e17f97d..983dc7f36 100644
+--- a/les/sync.go
++++ b/les/sync.go
+@@ -36,7 +36,6 @@ func (pm *ProtocolManager) syncer() {
+ 	// Start and ensure cleanup of sync mechanisms
+ 	//pm.fetcher.Start()
+ 	//defer pm.fetcher.Stop()
+-	defer pm.downloader.Terminate()
+
+ 	// Wait for different events to fire synchronisation operations
+ 	//forceSync := time.Tick(forceSyncCycle)
 diff --git a/les/backend.go b/les/backend.go
-index 333df920..450d8351 100644
+index 6a324cb0..e3844bf8 100644
 --- a/les/backend.go
 +++ b/les/backend.go
 @@ -20,7 +20,6 @@ package les
@@ -7,79 +93,14 @@ index 333df920..450d8351 100644
  	"fmt"
  	"sync"
 -	"time"
- 
+
  	"github.com/ethereum/go-ethereum/accounts"
  	"github.com/ethereum/go-ethereum/common"
-@@ -248,7 +247,6 @@ func (s *LightEthereum) Stop() error {
+@@ -250,7 +249,6 @@ func (s *LightEthereum) Stop() error {
- 
+
  	s.eventMux.Stop()
- 
+
 -	time.Sleep(time.Millisecond * 200)
  	s.chainDb.Close()
  	close(s.shutdownChan)
- 
-diff --git a/les/handler.go b/les/handler.go
-index 613fbb79..a6ae09ef 100644
---- a/les/handler.go
-+++ b/les/handler.go
-@@ -124,6 +124,10 @@ type ProtocolManager struct {
- 	// wait group is used for graceful shutdowns during downloading
- 	// and processing
- 	wg *sync.WaitGroup
-+
-+	// wait group is used for waiting for currend download
-+	// to finish (if running)
-+	downloads *sync.WaitGroup
- }
 
- // NewProtocolManager returns a new ethereum sub protocol manager. The Ethereum sub protocol manages peers capable
-@@ -145,6 +149,7 @@ func NewProtocolManager(chainConfig *params.ChainConfig, lightSync bool, protoco
- 		quitSync:    quitSync,
- 		wg:          wg,
- 		noMorePeers: make(chan struct{}),
-+		downloads:   &sync.WaitGroup{},
- 	}
- 	if odr != nil {
- 		manager.retriever = odr.retriever
-@@ -210,9 +215,32 @@ func NewProtocolManager(chainConfig *params.ChainConfig, lightSync bool, protoco
- 		manager.fetcher = newLightFetcher(manager)
- 	}
-
-+	go manager.monitorDownloads()
-+
- 	return manager, nil
- }
-
-+func (pm *ProtocolManager) monitorDownloads() {
-+	sub := pm.eventMux.Subscribe(downloader.StartEvent{}, downloader.DoneEvent{}, downloader.FailedEvent{})
-+	defer sub.Unsubscribe()
-+
-+	for {
-+		select {
-+		case event := <-sub.Chan():
-+			if event == nil {
-+				return
-+			}
-+
-+			switch event.Data.(type) {
-+			case downloader.StartEvent:
-+				pm.downloads.Add(1)
-+			case downloader.DoneEvent, downloader.FailedEvent:
-+				pm.downloads.Done()
-+			}
-+		}
-+	}
-+}
-+
- // removePeer initiates disconnection from a peer by removing it from the peer set
- func (pm *ProtocolManager) removePeer(id string) {
- 	pm.peers.Unregister(id)
-@@ -240,6 +267,8 @@ func (pm *ProtocolManager) Stop() {
-
- 	close(pm.quitSync) // quits syncer, fetcher
-
-+	pm.downloads.Wait() // Wait until current downloads are finished.
-+
- 	// Disconnect existing sessions.
- 	// This also closes the gate for any new registrations on the peer set.
- 	// sessions which are already established but not added to pm.peers yet

vendor/github.com/ethereum/go-ethereum/eth/downloader/downloader.go

@@ -141,6 +141,8 @@ type Downloader struct {
 	quitCh   chan struct{} // Quit channel to signal termination
 	quitLock sync.RWMutex  // Lock to prevent double closes
 
+	downloads sync.WaitGroup // Keeps track of the currently active downloads
+
 	// Testing hooks
 	syncInitHook     func(uint64, uint64)  // Method to call upon initiating a new sync run
 	bodyFetchHook    func([]*types.Header) // Method to call upon starting a block body fetch
@@ -398,7 +400,9 @@ func (d *Downloader) synchronise(id string, hash common.Hash, td *big.Int, mode
 // specified peer and head hash.
 func (d *Downloader) syncWithPeer(p *peerConnection, hash common.Hash, td *big.Int) (err error) {
 	d.mux.Post(StartEvent{})
+	d.downloads.Add(1)
 	defer func() {
+		d.downloads.Done()
 		// reset on error
 		if err != nil {
 			d.mux.Post(FailedEvent{err})
@@ -528,6 +532,10 @@ func (d *Downloader) Terminate() {
 
 	// Cancel any pending download requests
 	d.Cancel()
+
+	// Wait, so external dependencies aren't destroyed
+	// until the download processing is done.
+	d.downloads.Wait()
 }
 
 // fetchHeight retrieves the head header of the remote peer to aid in estimating

vendor/github.com/ethereum/go-ethereum/eth/handler.go

@@ -230,6 +230,9 @@ func (pm *ProtocolManager) Stop() {
 	// Quit fetcher, txsyncLoop.
 	close(pm.quitSync)
 
+	// Stop downloader and make sure that all the running downloads are complete.
+	pm.downloader.Terminate()
+
 	// Disconnect existing sessions.
 	// This also closes the gate for any new registrations on the peer set.
 	// sessions which are already established but not added to pm.peers yet

vendor/github.com/ethereum/go-ethereum/eth/sync.go

@@ -135,7 +135,6 @@ func (pm *ProtocolManager) syncer() {
 	// Start and ensure cleanup of sync mechanisms
 	pm.fetcher.Start()
 	defer pm.fetcher.Stop()
-	defer pm.downloader.Terminate()
 
 	// Wait for different events to fire synchronisation operations
 	forceSync := time.NewTicker(forceSyncCycle)

vendor/github.com/ethereum/go-ethereum/les/handler.go

@@ -123,10 +123,6 @@ type ProtocolManager struct {
 	// wait group is used for graceful shutdowns during downloading
 	// and processing
 	wg *sync.WaitGroup
-
-	// wait group is used for waiting for currend download
-	// to finish (if running)
-	downloads *sync.WaitGroup
 }
 
 // NewProtocolManager returns a new ethereum sub protocol manager. The Ethereum sub protocol manages peers capable
@@ -148,7 +144,6 @@ func NewProtocolManager(chainConfig *params.ChainConfig, lightSync bool, protoco
 		quitSync:    quitSync,
 		wg:          wg,
 		noMorePeers: make(chan struct{}),
-		downloads:   &sync.WaitGroup{},
 	}
 	if odr != nil {
 		manager.retriever = odr.retriever
@@ -214,32 +209,9 @@ func NewProtocolManager(chainConfig *params.ChainConfig, lightSync bool, protoco
 		manager.fetcher = newLightFetcher(manager)
 	}
 
-	go manager.monitorDownloads()
-
 	return manager, nil
 }
 
-func (pm *ProtocolManager) monitorDownloads() {
-	sub := pm.eventMux.Subscribe(downloader.StartEvent{}, downloader.DoneEvent{}, downloader.FailedEvent{})
-	defer sub.Unsubscribe()
-
-	for {
-		select {
-		case event := <-sub.Chan():
-			if event == nil {
-				return
-			}
-
-			switch event.Data.(type) {
-			case downloader.StartEvent:
-				pm.downloads.Add(1)
-			case downloader.DoneEvent, downloader.FailedEvent:
-				pm.downloads.Done()
-			}
-		}
-	}
-}
-
 // removePeer initiates disconnection from a peer by removing it from the peer set
 func (pm *ProtocolManager) removePeer(id string) {
 	pm.peers.Unregister(id)
@@ -269,7 +241,8 @@ func (pm *ProtocolManager) Stop() {
 
 	close(pm.quitSync) // quits syncer, fetcher
 
-	pm.downloads.Wait() // Wait until current downloads are finished.
+	// Stop downloader and make sure that all the running downloads are complete.
+	pm.downloader.Terminate()
 
 	// Disconnect existing sessions.
 	// This also closes the gate for any new registrations on the peer set.

vendor/github.com/ethereum/go-ethereum/les/sync.go

@@ -36,7 +36,6 @@ func (pm *ProtocolManager) syncer() {
 	// Start and ensure cleanup of sync mechanisms
 	//pm.fetcher.Start()
 	//defer pm.fetcher.Stop()
-	defer pm.downloader.Terminate()
 
 	// Wait for different events to fire synchronisation operations
 	//forceSync := time.Tick(forceSyncCycle)