core, eth: polish

core/blockchain.go

@@ -1226,7 +1226,7 @@ func (bc *BlockChain) stopWithoutSaving() {
 	bc.scope.Close()
 
 	// Signal shutdown to all goroutines.
-	bc.StopInsert()
+	bc.InterruptInsert(true)
 
 	// Now wait for all chain modifications to end and persistent goroutines to exit.
 	//
@@ -1300,16 +1300,15 @@ func (bc *BlockChain) Stop() {
 	log.Info("Blockchain stopped")
 }
 
-// StopInsert interrupts all insertion methods, causing them to return
-// errInsertionInterrupted as soon as possible. Insertion is permanently disabled after
-// calling this method.
-func (bc *BlockChain) StopInsert() {
+// InterruptInsert interrupts all insertion methods, causing them to return
+// errInsertionInterrupted as soon as possible, or resume the chain insertion
+// if required.
+func (bc *BlockChain) InterruptInsert(on bool) {
+	if on {
 		bc.procInterrupt.Store(true)
-}
-
-// ResumeInsert re-enables the blockchain insertion, which is used to rewinding the chain to
-func (bc *BlockChain) ResumeInsert() {
+	} else {
 		bc.procInterrupt.Store(false)
+	}
 }
 
 // insertStopped returns true after StopInsert has been called.

eth/api_backend.go

@@ -62,10 +62,8 @@ func (b *EthAPIBackend) CurrentBlock() *types.Header {
 }
 
 func (b *EthAPIBackend) SetHead(number uint64) {
-	b.eth.blockchain.StopInsert()
 	b.eth.handler.downloader.Cancel()
 	b.eth.blockchain.SetHead(number)
-	b.eth.blockchain.ResumeInsert()
 }
 
 func (b *EthAPIBackend) HeaderByNumber(ctx context.Context, number rpc.BlockNumber) (*types.Header, error) {

eth/downloader/downloader.go

@@ -199,8 +199,8 @@ type BlockChain interface {
 	// InsertChain inserts a batch of blocks into the local chain.
 	InsertChain(types.Blocks) (int, error)
 
-	// StopInsert interrupts the inserting process.
-	StopInsert()
+	// InterruptInsert whether disables the chain insertion.
+	InterruptInsert(on bool)
 
 	// InsertReceiptChain inserts a batch of blocks along with their receipts
 	// into the local chain. Blocks older than the specified `ancientLimit`
@@ -630,16 +630,15 @@ func (d *Downloader) cancel() {
 // Cancel aborts all of the operations and waits for all download goroutines to
 // finish before returning.
 func (d *Downloader) Cancel() {
+	d.blockchain.InterruptInsert(true)
 	d.cancel()
 	d.cancelWg.Wait()
+	d.blockchain.InterruptInsert(false)
 }
 
 // Terminate interrupts the downloader, canceling all pending operations.
 // The downloader cannot be reused after calling Terminate.
 func (d *Downloader) Terminate() {
-	// Signal to stop inserting in-flight blocks
-	d.blockchain.StopInsert()
-
 	// Close the termination channel (make sure double close is allowed)
 	d.quitLock.Lock()
 	select {