core, eth, trie: fix data races and review issues

core/blockchain.go

@@ -178,21 +178,21 @@ func (self *BlockChain) loadLastState() error {
 	fastTd := self.GetTd(self.currentFastBlock.Hash())
 
 	glog.V(logger.Info).Infof("Last header: #%d [%x…] TD=%v", self.currentHeader.Number, self.currentHeader.Hash().Bytes()[:4], headerTd)
-	glog.V(logger.Info).Infof("Fast block: #%d [%x…] TD=%v", self.currentFastBlock.Number(), self.currentFastBlock.Hash().Bytes()[:4], fastTd)
 	glog.V(logger.Info).Infof("Last block: #%d [%x…] TD=%v", self.currentBlock.Number(), self.currentBlock.Hash().Bytes()[:4], blockTd)
+	glog.V(logger.Info).Infof("Fast block: #%d [%x…] TD=%v", self.currentFastBlock.Number(), self.currentFastBlock.Hash().Bytes()[:4], fastTd)
 
 	return nil
 }
 
-// SetHead rewind the local chain to a new head entity. In the case of headers,
+// SetHead rewinds the local chain to a new head. In the case of headers, everything
-// everything above the new head will be deleted and the new one set. In the case
+// above the new head will be deleted and the new one set. In the case of blocks
-// of blocks though, the head may be further rewound if block bodies are missing
+// though, the head may be further rewound if block bodies are missing (non-archive
-// (non-archive nodes after a fast sync).
+// nodes after a fast sync).
 func (bc *BlockChain) SetHead(head uint64) {
 	bc.mu.Lock()
 	defer bc.mu.Unlock()
 
-	// Figure out the highest known canonical assignment
+	// Figure out the highest known canonical headers and/or blocks
 	height := uint64(0)
 	if bc.currentHeader != nil {
 		if hh := bc.currentHeader.Number.Uint64(); hh > height {
@@ -266,7 +266,7 @@ func (bc *BlockChain) SetHead(head uint64) {
 // FastSyncCommitHead sets the current head block to the one defined by the hash
 // irrelevant what the chain contents were prior.
 func (self *BlockChain) FastSyncCommitHead(hash common.Hash) error {
-	// Make sure that both the block as well at it's state trie exists
+	// Make sure that both the block as well at its state trie exists
 	block := self.GetBlock(hash)
 	if block == nil {
 		return fmt.Errorf("non existent block [%x…]", hash[:4])
@@ -298,7 +298,7 @@ func (self *BlockChain) LastBlockHash() common.Hash {
 }
 
 // CurrentHeader retrieves the current head header of the canonical chain. The
-// header is retrieved from the chain manager's internal cache.
+// header is retrieved from the blockchain's internal cache.
 func (self *BlockChain) CurrentHeader() *types.Header {
 	self.mu.RLock()
 	defer self.mu.RUnlock()
@@ -307,7 +307,7 @@ func (self *BlockChain) CurrentHeader() *types.Header {
 }
 
 // CurrentBlock retrieves the current head block of the canonical chain. The
-// block is retrieved from the chain manager's internal cache.
+// block is retrieved from the blockchain's internal cache.
 func (self *BlockChain) CurrentBlock() *types.Block {
 	self.mu.RLock()
 	defer self.mu.RUnlock()
@@ -316,7 +316,7 @@ func (self *BlockChain) CurrentBlock() *types.Block {
 }
 
 // CurrentFastBlock retrieves the current fast-sync head block of the canonical
-// chain. The block is retrieved from the chain manager's internal cache.
+// chain. The block is retrieved from the blockchain's internal cache.
 func (self *BlockChain) CurrentFastBlock() *types.Block {
 	self.mu.RLock()
 	defer self.mu.RUnlock()
@@ -353,7 +353,7 @@ func (bc *BlockChain) ResetWithGenesisBlock(genesis *types.Block) {
 	bc.mu.Lock()
 	defer bc.mu.Unlock()
 
-	// Prepare the genesis block and reinitialize the chain
+	// Prepare the genesis block and reinitialise the chain
 	if err := WriteTd(bc.chainDb, genesis.Hash(), genesis.Difficulty()); err != nil {
 		glog.Fatalf("failed to write genesis block TD: %v", err)
 	}
@@ -403,7 +403,7 @@ func (self *BlockChain) ExportN(w io.Writer, first uint64, last uint64) error {
 // insert injects a new head block into the current block chain. This method
 // assumes that the block is indeed a true head. It will also reset the head
 // header and the head fast sync block to this very same block to prevent them
-// from diverging on a different header chain.
+// from pointing to a possibly old canonical chain (i.e. side chain by now).
 //
 // Note, this function assumes that the `mu` mutex is held!
 func (bc *BlockChain) insert(block *types.Block) {
@@ -625,10 +625,10 @@ const (
 
 // writeHeader writes a header into the local chain, given that its parent is
 // already known. If the total difficulty of the newly inserted header becomes
-// greater than the old known TD, the canonical chain is re-routed.
+// greater than the current known TD, the canonical chain is re-routed.
 //
 // Note: This method is not concurrent-safe with inserting blocks simultaneously
-// into the chain, as side effects caused by reorganizations cannot be emulated
+// into the chain, as side effects caused by reorganisations cannot be emulated
 // without the real blocks. Hence, writing headers directly should only be done
 // in two scenarios: pure-header mode of operation (light clients), or properly
 // separated header/block phases (non-archive clients).
@@ -678,10 +678,9 @@ func (self *BlockChain) writeHeader(header *types.Header) error {
 	return nil
 }
 
-// InsertHeaderChain will attempt to insert the given header chain in to the
+// InsertHeaderChain attempts to insert the given header chain in to the local
-// local chain, possibly creating a fork. If an error is returned,  it will
+// chain, possibly creating a reorg. If an error is returned, it will return the
-// return the index number of the failing header as well an error describing
+// index number of the failing header as well an error describing what went wrong.
-// what went wrong.
 //
 // The verify parameter can be used to fine tune whether nonce verification
 // should be done or not. The reason behind the optional check is because some
@@ -766,10 +765,6 @@ func (self *BlockChain) InsertHeaderChain(chain []*types.Header, checkFreq int)
 	pending.Wait()
 
 	// If anything failed, report
-	if atomic.LoadInt32(&self.procInterrupt) == 1 {
-		glog.V(logger.Debug).Infoln("premature abort during receipt chain processing")
-		return 0, nil
-	}
 	if failed > 0 {
 		for i, err := range errs {
 			if err != nil {
@@ -807,6 +802,9 @@ func (self *BlockChain) InsertHeaderChain(chain []*types.Header, checkFreq int)
 // Rollback is designed to remove a chain of links from the database that aren't
 // certain enough to be valid.
 func (self *BlockChain) Rollback(chain []common.Hash) {
+	self.mu.Lock()
+	defer self.mu.Unlock()
+
 	for i := len(chain) - 1; i >= 0; i-- {
 		hash := chain[i]
 
@@ -920,10 +918,6 @@ func (self *BlockChain) InsertReceiptChain(blockChain types.Blocks, receiptChain
 	pending.Wait()
 
 	// If anything failed, report
-	if atomic.LoadInt32(&self.procInterrupt) == 1 {
-		glog.V(logger.Debug).Infoln("premature abort during receipt chain processing")
-		return 0, nil
-	}
 	if failed > 0 {
 		for i, err := range errs {
 			if err != nil {
@@ -931,6 +925,10 @@ func (self *BlockChain) InsertReceiptChain(blockChain types.Blocks, receiptChain
 			}
 		}
 	}
+	if atomic.LoadInt32(&self.procInterrupt) == 1 {
+		glog.V(logger.Debug).Infoln("premature abort during receipt chain processing")
+		return 0, nil
+	}
 	// Update the head fast sync block if better
 	self.mu.Lock()
 	head := blockChain[len(errs)-1]

core/state/sync.go

@@ -33,7 +33,6 @@ type StateSync trie.TrieSync
 
 // NewStateSync create a new state trie download scheduler.
 func NewStateSync(root common.Hash, database ethdb.Database) *StateSync {
-	// Pre-declare the result syncer t
 	var syncer *trie.TrieSync
 
 	callback := func(leaf []byte, parent common.Hash) error {

core/types/receipt.go

@@ -67,7 +67,7 @@ func (r *Receipt) DecodeRLP(s *rlp.Stream) error {
 	return nil
 }
 
-// RlpEncode implements common.RlpEncode required for SHA derivation.
+// RlpEncode implements common.RlpEncode required for SHA3 derivation.
 func (r *Receipt) RlpEncode() []byte {
 	bytes, err := rlp.EncodeToBytes(r)
 	if err != nil {
@@ -82,7 +82,7 @@ func (r *Receipt) String() string {
 }
 
 // ReceiptForStorage is a wrapper around a Receipt that flattens and parses the
-// entire content of a receipt, opposed to only the consensus fields originally.
+// entire content of a receipt, as opposed to only the consensus fields originally.
 type ReceiptForStorage Receipt
 
 // EncodeRLP implements rlp.Encoder, and flattens all content fields of a receipt
@@ -95,8 +95,8 @@ func (r *ReceiptForStorage) EncodeRLP(w io.Writer) error {
 	return rlp.Encode(w, []interface{}{r.PostState, r.CumulativeGasUsed, r.Bloom, r.TxHash, r.ContractAddress, logs, r.GasUsed})
 }
 
-// DecodeRLP implements rlp.Decoder, and loads the consensus fields of a receipt
+// DecodeRLP implements rlp.Decoder, and loads both consensus and implementation
-// from an RLP stream.
+// fields of a receipt from an RLP stream.
 func (r *ReceiptForStorage) DecodeRLP(s *rlp.Stream) error {
 	var receipt struct {
 		PostState         []byte
@@ -125,7 +125,7 @@ func (r *ReceiptForStorage) DecodeRLP(s *rlp.Stream) error {
 // Receipts is a wrapper around a Receipt array to implement types.DerivableList.
 type Receipts []*Receipt
 
-// RlpEncode implements common.RlpEncode required for SHA derivation.
+// RlpEncode implements common.RlpEncode required for SHA3 derivation.
 func (r Receipts) RlpEncode() []byte {
 	bytes, err := rlp.EncodeToBytes(r)
 	if err != nil {

core/vm/log.go

@@ -66,6 +66,6 @@ func (l *Log) String() string {
 type Logs []*Log
 
 // LogForStorage is a wrapper around a Log that flattens and parses the entire
-// content of a log, opposed to only the consensus fields originally (by hiding
+// content of a log, as opposed to only the consensus fields originally (by hiding
 // the rlp interface methods).
 type LogForStorage Log

eth/downloader/downloader.go

@@ -19,6 +19,7 @@ package downloader
 
 import (
 	"errors"
+	"fmt"
 	"math"
 	"math/big"
 	"strings"
@@ -85,6 +86,7 @@ var (
 	errCancelHeaderFetch  = errors.New("block header download canceled (requested)")
 	errCancelBodyFetch    = errors.New("block body download canceled (requested)")
 	errCancelReceiptFetch = errors.New("receipt download canceled (requested)")
+	errCancelStateFetch   = errors.New("state data download canceled (requested)")
 	errNoSyncActive       = errors.New("no sync active")
 )
 
@@ -844,7 +846,7 @@ func (d *Downloader) fetchBlocks61(from uint64) error {
 
 			for _, peer := range idles {
 				// Short circuit if throttling activated
-				if d.queue.ThrottleBlocks() {
+				if d.queue.ShouldThrottleBlocks() {
 					throttled = true
 					break
 				}
@@ -860,8 +862,13 @@ func (d *Downloader) fetchBlocks61(from uint64) error {
 				}
 				// Fetch the chunk and make sure any errors return the hashes to the queue
 				if err := peer.Fetch61(request); err != nil {
-					glog.V(logger.Error).Infof("%v: fetch failed, rescheduling", peer)
+					// Although we could try and make an attempt to fix this, this error really
-					d.queue.CancelBlocks(request)
+					// means that we've double allocated a fetch task to a peer. If that is the
+					// case, the internal state of the downloader and the queue is very wrong so
+					// better hard crash and note the error instead of silently accumulating into
+					// a much bigger issue.
+					panic(fmt.Sprintf("%v: fetch assignment failed, hard panic", peer))
+					d.queue.CancelBlocks(request) // noop for now
 				}
 			}
 			// Make sure that we have peers available for fetching. If all peers have been tried
@@ -1230,12 +1237,11 @@ func (d *Downloader) fetchBodies(from uint64) error {
 		expire   = func() []string { return d.queue.ExpireBodies(bodyHardTTL) }
 		fetch    = func(p *peer, req *fetchRequest) error { return p.FetchBodies(req) }
 		capacity = func(p *peer) int { return p.BlockCapacity() }
-		getIdles = func() ([]*peer, int) { return d.peers.BodyIdlePeers() }
+		setIdle  = func(p *peer) { p.SetBodiesIdle() }
-		setIdle  = func(p *peer) { p.SetBlocksIdle() }
 	)
 	err := d.fetchParts(errCancelBodyFetch, d.bodyCh, deliver, d.bodyWakeCh, expire,
-		d.queue.PendingBlocks, d.queue.InFlightBlocks, d.queue.ThrottleBlocks, d.queue.ReserveBodies,
+		d.queue.PendingBlocks, d.queue.InFlightBlocks, d.queue.ShouldThrottleBlocks, d.queue.ReserveBodies,
-		d.bodyFetchHook, fetch, d.queue.CancelBodies, capacity, getIdles, setIdle, "Body")
+		d.bodyFetchHook, fetch, d.queue.CancelBodies, capacity, d.peers.BodyIdlePeers, setIdle, "Body")
 
 	glog.V(logger.Debug).Infof("Block body download terminated: %v", err)
 	return err
@@ -1252,13 +1258,13 @@ func (d *Downloader) fetchReceipts(from uint64) error {
 			pack := packet.(*receiptPack)
 			return d.queue.DeliverReceipts(pack.peerId, pack.receipts)
 		}
-		expire   = func() []string { return d.queue.ExpireReceipts(bodyHardTTL) }
+		expire   = func() []string { return d.queue.ExpireReceipts(receiptHardTTL) }
 		fetch    = func(p *peer, req *fetchRequest) error { return p.FetchReceipts(req) }
 		capacity = func(p *peer) int { return p.ReceiptCapacity() }
 		setIdle  = func(p *peer) { p.SetReceiptsIdle() }
 	)
 	err := d.fetchParts(errCancelReceiptFetch, d.receiptCh, deliver, d.receiptWakeCh, expire,
-		d.queue.PendingReceipts, d.queue.InFlightReceipts, d.queue.ThrottleReceipts, d.queue.ReserveReceipts,
+		d.queue.PendingReceipts, d.queue.InFlightReceipts, d.queue.ShouldThrottleReceipts, d.queue.ReserveReceipts,
 		d.receiptFetchHook, fetch, d.queue.CancelReceipts, capacity, d.peers.ReceiptIdlePeers, setIdle, "Receipt")
 
 	glog.V(logger.Debug).Infof("Receipt download terminated: %v", err)
@@ -1307,9 +1313,9 @@ func (d *Downloader) fetchNodeData() error {
 		capacity = func(p *peer) int { return p.NodeDataCapacity() }
 		setIdle  = func(p *peer) { p.SetNodeDataIdle() }
 	)
-	err := d.fetchParts(errCancelReceiptFetch, d.stateCh, deliver, d.stateWakeCh, expire,
+	err := d.fetchParts(errCancelStateFetch, d.stateCh, deliver, d.stateWakeCh, expire,
 		d.queue.PendingNodeData, d.queue.InFlightNodeData, throttle, reserve, nil, fetch,
-		d.queue.CancelNodeData, capacity, d.peers.ReceiptIdlePeers, setIdle, "State")
+		d.queue.CancelNodeData, capacity, d.peers.NodeDataIdlePeers, setIdle, "State")
 
 	glog.V(logger.Debug).Infof("Node state data download terminated: %v", err)
 	return err
@@ -1475,8 +1481,13 @@ func (d *Downloader) fetchParts(errCancel error, deliveryCh chan dataPack, deliv
 					fetchHook(request.Headers)
 				}
 				if err := fetch(peer, request); err != nil {
-					glog.V(logger.Error).Infof("%v: %s fetch failed, rescheduling", peer, strings.ToLower(kind))
+					// Although we could try and make an attempt to fix this, this error really
-					cancel(request)
+					// means that we've double allocated a fetch task to a peer. If that is the
+					// case, the internal state of the downloader and the queue is very wrong so
+					// better hard crash and note the error instead of silently accumulating into
+					// a much bigger issue.
+					panic(fmt.Sprintf("%v: %s fetch assignment failed, hard panic", peer, strings.ToLower(kind)))
+					cancel(request) // noop for now
 				}
 				running = true
 			}
@@ -1556,7 +1567,7 @@ func (d *Downloader) process() {
 					blocks = append(blocks, types.NewBlockWithHeader(result.Header).WithBody(result.Transactions, result.Uncles))
 				case d.mode == FastSync:
 					blocks = append(blocks, types.NewBlockWithHeader(result.Header).WithBody(result.Transactions, result.Uncles))
-					if result.Header.Number.Uint64() <= d.queue.fastSyncPivot {
+					if result.Header.Number.Uint64() <= d.queue.FastSyncPivot() {
 						receipts = append(receipts, result.Receipts)
 					}
 				case d.mode == LightSync:
@@ -1574,7 +1585,7 @@ func (d *Downloader) process() {
 
 			case len(receipts) > 0:
 				index, err = d.insertReceipts(blocks, receipts)
-				if err == nil && blocks[len(blocks)-1].NumberU64() == d.queue.fastSyncPivot {
+				if err == nil && blocks[len(blocks)-1].NumberU64() == d.queue.FastSyncPivot() {
 					index, err = len(blocks)-1, d.commitHeadBlock(blocks[len(blocks)-1].Hash())
 				}
 			default:

eth/downloader/downloader_test.go

@@ -43,6 +43,18 @@ var (
 	genesis     = core.GenesisBlockForTesting(testdb, testAddress, big.NewInt(1000000000))
 )
 
+// This is a very ugly hack, but needed to catch a Heisenbug :P. The windows CI
+// servers extremely rarely lock up in this test suite, and adding any logging
+// or measurements simply hides the error completely. This snippet will ensure
+// that in the case of a lockup, we'll at least have a cash dump of the goroutines
+// to at least get a glimpse into what state the tests were in.
+func init() {
+	go func() {
+		time.Sleep(8 * time.Minute)
+		panic("Test probably deadlocked")
+	}()
+}
+
 // makeChain creates a chain of n blocks starting at and including parent.
 // the returned hash chain is ordered head->parent. In addition, every 3rd block
 // contains a transaction and every 5th an uncle to allow testing correct block
@@ -730,6 +742,7 @@ func testThrottling(t *testing.T, protocol int, mode SyncMode) {
 		for start := time.Now(); time.Since(start) < time.Second; {
 			time.Sleep(25 * time.Millisecond)
 
+			tester.lock.RLock()
 			tester.downloader.queue.lock.RLock()
 			cached = len(tester.downloader.queue.blockDonePool)
 			if mode == FastSync {
@@ -739,16 +752,22 @@ func testThrottling(t *testing.T, protocol int, mode SyncMode) {
 					}
 				}
 			}
+			retrieved = len(tester.ownBlocks)
 			tester.downloader.queue.lock.RUnlock()
+			tester.lock.RUnlock()
 
-			if cached == blockCacheLimit || len(tester.ownBlocks)+cached+int(atomic.LoadUint32(&blocked)) == targetBlocks+1 {
+			if cached == blockCacheLimit || retrieved+cached+int(atomic.LoadUint32(&blocked)) == targetBlocks+1 {
 				break
 			}
 		}
 		// Make sure we filled up the cache, then exhaust it
 		time.Sleep(25 * time.Millisecond) // give it a chance to screw up
-		if cached != blockCacheLimit && len(tester.ownBlocks)+cached+int(atomic.LoadUint32(&blocked)) != targetBlocks+1 {
+
-			t.Fatalf("block count mismatch: have %v, want %v (owned %v, target %v)", cached, blockCacheLimit, len(tester.ownBlocks), targetBlocks+1)
+		tester.lock.RLock()
+		retrieved = len(tester.ownBlocks)
+		tester.lock.RUnlock()
+		if cached != blockCacheLimit && retrieved+cached+int(atomic.LoadUint32(&blocked)) != targetBlocks+1 {
+			t.Fatalf("block count mismatch: have %v, want %v (owned %v, blocked %v, target %v)", cached, blockCacheLimit, retrieved, atomic.LoadUint32(&blocked), targetBlocks+1)
 		}
 		// Permit the blocked blocks to import
 		if atomic.LoadUint32(&blocked) > 0 {
@@ -921,12 +940,12 @@ func testMultiProtoSync(t *testing.T, protocol int, mode SyncMode) {
 
 	// Create peers of every type
 	tester := newTester(mode)
-	tester.newPeer("peer 61", 61, hashes, headers, blocks, receipts)
+	tester.newPeer("peer 61", 61, hashes, nil, blocks, nil)
-	tester.newPeer("peer 62", 62, hashes, headers, blocks, receipts)
+	tester.newPeer("peer 62", 62, hashes, headers, blocks, nil)
 	tester.newPeer("peer 63", 63, hashes, headers, blocks, receipts)
 	tester.newPeer("peer 64", 64, hashes, headers, blocks, receipts)
 
-	// Synchronise with the requestd peer and make sure all blocks were retrieved
+	// Synchronise with the requested peer and make sure all blocks were retrieved
 	if err := tester.sync(fmt.Sprintf("peer %d", protocol), nil); err != nil {
 		t.Fatalf("failed to synchronise blocks: %v", err)
 	}

eth/downloader/modes.go

@@ -20,7 +20,7 @@ package downloader
 type SyncMode int
 
 const (
-	FullSync  SyncMode = iota // Synchronise the entire block-chain history from full blocks
+	FullSync  SyncMode = iota // Synchronise the entire blockchain history from full blocks
-	FastSync                  // Quikcly download the headers, full sync only at the chain head
+	FastSync                  // Quickly download the headers, full sync only at the chain head
 	LightSync                 // Download only the headers and terminate afterwards
 )

eth/downloader/peer.go

@@ -124,6 +124,10 @@ func (p *peer) Reset() {
 
 // Fetch61 sends a block retrieval request to the remote peer.
 func (p *peer) Fetch61(request *fetchRequest) error {
+	// Sanity check the protocol version
+	if p.version != 61 {
+		panic(fmt.Sprintf("block fetch [eth/61] requested on eth/%d", p.version))
+	}
 	// Short circuit if the peer is already fetching
 	if !atomic.CompareAndSwapInt32(&p.blockIdle, 0, 1) {
 		return errAlreadyFetching
@@ -142,6 +146,10 @@ func (p *peer) Fetch61(request *fetchRequest) error {
 
 // FetchBodies sends a block body retrieval request to the remote peer.
 func (p *peer) FetchBodies(request *fetchRequest) error {
+	// Sanity check the protocol version
+	if p.version < 62 {
+		panic(fmt.Sprintf("body fetch [eth/62+] requested on eth/%d", p.version))
+	}
 	// Short circuit if the peer is already fetching
 	if !atomic.CompareAndSwapInt32(&p.blockIdle, 0, 1) {
 		return errAlreadyFetching
@@ -160,6 +168,10 @@ func (p *peer) FetchBodies(request *fetchRequest) error {
 
 // FetchReceipts sends a receipt retrieval request to the remote peer.
 func (p *peer) FetchReceipts(request *fetchRequest) error {
+	// Sanity check the protocol version
+	if p.version < 63 {
+		panic(fmt.Sprintf("body fetch [eth/63+] requested on eth/%d", p.version))
+	}
 	// Short circuit if the peer is already fetching
 	if !atomic.CompareAndSwapInt32(&p.receiptIdle, 0, 1) {
 		return errAlreadyFetching
@@ -178,6 +190,10 @@ func (p *peer) FetchReceipts(request *fetchRequest) error {
 
 // FetchNodeData sends a node state data retrieval request to the remote peer.
 func (p *peer) FetchNodeData(request *fetchRequest) error {
+	// Sanity check the protocol version
+	if p.version < 63 {
+		panic(fmt.Sprintf("node data fetch [eth/63+] requested on eth/%d", p.version))
+	}
 	// Short circuit if the peer is already fetching
 	if !atomic.CompareAndSwapInt32(&p.stateIdle, 0, 1) {
 		return errAlreadyFetching
@@ -196,35 +212,35 @@ func (p *peer) FetchNodeData(request *fetchRequest) error {
 
 // SetBlocksIdle sets the peer to idle, allowing it to execute new retrieval requests.
 // Its block retrieval allowance will also be updated either up- or downwards,
-// depending on whether the previous fetch completed in time or not.
+// depending on whether the previous fetch completed in time.
 func (p *peer) SetBlocksIdle() {
 	p.setIdle(p.blockStarted, blockSoftTTL, blockHardTTL, MaxBlockFetch, &p.blockCapacity, &p.blockIdle)
 }
 
 // SetBodiesIdle sets the peer to idle, allowing it to execute new retrieval requests.
 // Its block body retrieval allowance will also be updated either up- or downwards,
-// depending on whether the previous fetch completed in time or not.
+// depending on whether the previous fetch completed in time.
 func (p *peer) SetBodiesIdle() {
-	p.setIdle(p.blockStarted, bodySoftTTL, bodyHardTTL, MaxBlockFetch, &p.blockCapacity, &p.blockIdle)
+	p.setIdle(p.blockStarted, bodySoftTTL, bodyHardTTL, MaxBodyFetch, &p.blockCapacity, &p.blockIdle)
 }
 
 // SetReceiptsIdle sets the peer to idle, allowing it to execute new retrieval requests.
 // Its receipt retrieval allowance will also be updated either up- or downwards,
-// depending on whether the previous fetch completed in time or not.
+// depending on whether the previous fetch completed in time.
 func (p *peer) SetReceiptsIdle() {
 	p.setIdle(p.receiptStarted, receiptSoftTTL, receiptHardTTL, MaxReceiptFetch, &p.receiptCapacity, &p.receiptIdle)
 }
 
 // SetNodeDataIdle sets the peer to idle, allowing it to execute new retrieval
 // requests. Its node data retrieval allowance will also be updated either up- or
-// downwards, depending on whether the previous fetch completed in time or not.
+// downwards, depending on whether the previous fetch completed in time.
 func (p *peer) SetNodeDataIdle() {
 	p.setIdle(p.stateStarted, stateSoftTTL, stateSoftTTL, MaxStateFetch, &p.stateCapacity, &p.stateIdle)
 }
 
 // setIdle sets the peer to idle, allowing it to execute new retrieval requests.
 // Its data retrieval allowance will also be updated either up- or downwards,
-// depending on whether the previous fetch completed in time or not.
+// depending on whether the previous fetch completed in time.
 func (p *peer) setIdle(started time.Time, softTTL, hardTTL time.Duration, maxFetch int, capacity, idle *int32) {
 	// Update the peer's download allowance based on previous performance
 	scale := 2.0

eth/downloader/queue.go

@@ -56,9 +56,8 @@ type fetchRequest struct {
 	Time    time.Time           // Time when the request was made
 }
 
-// fetchResult is the assembly collecting partial results from potentially more
+// fetchResult is a struct collecting partial results from data fetchers until
-// than one fetcher routines, until all outstanding retrievals complete and the
+// all outstanding pieces complete and the result as a whole can be processed.
-// result as a whole can be processed.
 type fetchResult struct {
 	Pending int // Number of data fetches still pending
 
@@ -89,7 +88,7 @@ type queue struct {
 	receiptPendPool  map[string]*fetchRequest      // [eth/63] Currently pending receipt retrieval operations
 	receiptDonePool  map[common.Hash]struct{}      // [eth/63] Set of the completed receipt fetches
 
-	stateTaskIndex int                      // [eth/63] Counter indexing the added hashes to ensure prioritized retrieval order
+	stateTaskIndex int                      // [eth/63] Counter indexing the added hashes to ensure prioritised retrieval order
 	stateTaskPool  map[common.Hash]int      // [eth/63] Pending node data retrieval tasks, mapping to their priority
 	stateTaskQueue *prque.Prque             // [eth/63] Priority queue of the hashes to fetch the node data for
 	statePendPool  map[string]*fetchRequest // [eth/63] Currently pending node data retrieval operations
@@ -97,10 +96,10 @@ type queue struct {
 	stateDatabase   ethdb.Database   // [eth/63] Trie database to populate during state reassembly
 	stateScheduler  *state.StateSync // [eth/63] State trie synchronisation scheduler and integrator
 	stateProcessors int32            // [eth/63] Number of currently running state processors
-	stateSchedLock  sync.RWMutex     // [eth/63] Lock serializing access to the state scheduler
+	stateSchedLock  sync.RWMutex     // [eth/63] Lock serialising access to the state scheduler
 
 	resultCache  []*fetchResult // Downloaded but not yet delivered fetch results
-	resultOffset uint64         // Offset of the first cached fetch result in the block-chain
+	resultOffset uint64         // Offset of the first cached fetch result in the block chain
 
 	lock sync.RWMutex
 }
@@ -233,9 +232,17 @@ func (q *queue) Idle() bool {
 	return (queued + pending + cached) == 0
 }
 
-// ThrottleBlocks checks if the download should be throttled (active block (body)
+// FastSyncPivot retrieves the currently used fast sync pivot point.
+func (q *queue) FastSyncPivot() uint64 {
+	q.lock.RLock()
+	defer q.lock.RUnlock()
+
+	return q.fastSyncPivot
+}
+
+// ShouldThrottleBlocks checks if the download should be throttled (active block (body)
 // fetches exceed block cache).
-func (q *queue) ThrottleBlocks() bool {
+func (q *queue) ShouldThrottleBlocks() bool {
 	q.lock.RLock()
 	defer q.lock.RUnlock()
 
@@ -248,9 +255,9 @@ func (q *queue) ThrottleBlocks() bool {
 	return pending >= len(q.resultCache)-len(q.blockDonePool)
 }
 
-// ThrottleReceipts checks if the download should be throttled (active receipt
+// ShouldThrottleReceipts checks if the download should be throttled (active receipt
 // fetches exceed block cache).
-func (q *queue) ThrottleReceipts() bool {
+func (q *queue) ShouldThrottleReceipts() bool {
 	q.lock.RLock()
 	defer q.lock.RUnlock()
 
@@ -269,7 +276,7 @@ func (q *queue) Schedule61(hashes []common.Hash, fifo bool) []common.Hash {
 	q.lock.Lock()
 	defer q.lock.Unlock()
 
-	// Insert all the hashes prioritized in the arrival order
+	// Insert all the hashes prioritised in the arrival order
 	inserts := make([]common.Hash, 0, len(hashes))
 	for _, hash := range hashes {
 		// Skip anything we already have
@@ -297,10 +304,10 @@ func (q *queue) Schedule(headers []*types.Header, from uint64) []*types.Header {
 	q.lock.Lock()
 	defer q.lock.Unlock()
 
-	// Insert all the headers prioritized by the contained block number
+	// Insert all the headers prioritised by the contained block number
 	inserts := make([]*types.Header, 0, len(headers))
 	for _, header := range headers {
-		// Make sure chain order is honored and preserved throughout
+		// Make sure chain order is honoured and preserved throughout
 		hash := header.Hash()
 		if header.Number == nil || header.Number.Uint64() != from {
 			glog.V(logger.Warn).Infof("Header #%v [%x] broke chain ordering, expected %d", header.Number, hash[:4], from)
@@ -411,6 +418,9 @@ func (q *queue) TakeResults() []*fetchResult {
 // ReserveBlocks reserves a set of block hashes for the given peer, skipping any
 // previously failed download.
 func (q *queue) ReserveBlocks(p *peer, count int) *fetchRequest {
+	q.lock.Lock()
+	defer q.lock.Unlock()
+
 	return q.reserveHashes(p, count, q.hashQueue, nil, q.blockPendPool, len(q.resultCache)-len(q.blockDonePool))
 }
 
@@ -430,17 +440,21 @@ func (q *queue) ReserveNodeData(p *peer, count int) *fetchRequest {
 			}
 		}
 	}
+	q.lock.Lock()
+	defer q.lock.Unlock()
+
 	return q.reserveHashes(p, count, q.stateTaskQueue, generator, q.statePendPool, count)
 }
 
 // reserveHashes reserves a set of hashes for the given peer, skipping previously
 // failed ones.
+//
+// Note, this method expects the queue lock to be already held for writing. The
+// reason the lock is not obtained in here is because the parameters already need
+// to access the queue, so they already need a lock anyway.
 func (q *queue) reserveHashes(p *peer, count int, taskQueue *prque.Prque, taskGen func(int), pendPool map[string]*fetchRequest, maxPending int) *fetchRequest {
-	q.lock.Lock()
+	// Short circuit if the peer's already downloading something (sanity check to
-	defer q.lock.Unlock()
+	// not corrupt state)
-
-	// Short circuit if the peer's already downloading something (sanity check not
-	// to corrupt state)
 	if _, ok := pendPool[p.id]; ok {
 		return nil
 	}
@@ -492,30 +506,37 @@ func (q *queue) reserveHashes(p *peer, count int, taskQueue *prque.Prque, taskGe
 // previously failed downloads. Beside the next batch of needed fetches, it also
 // returns a flag whether empty blocks were queued requiring processing.
 func (q *queue) ReserveBodies(p *peer, count int) (*fetchRequest, bool, error) {
-	noop := func(header *types.Header) bool {
+	isNoop := func(header *types.Header) bool {
 		return header.TxHash == types.EmptyRootHash && header.UncleHash == types.EmptyUncleHash
 	}
-	return q.reserveHeaders(p, count, q.blockTaskPool, q.blockTaskQueue, q.blockPendPool, q.blockDonePool, noop)
+	q.lock.Lock()
+	defer q.lock.Unlock()
+
+	return q.reserveHeaders(p, count, q.blockTaskPool, q.blockTaskQueue, q.blockPendPool, q.blockDonePool, isNoop)
 }
 
 // ReserveReceipts reserves a set of receipt fetches for the given peer, skipping
 // any previously failed downloads. Beside the next batch of needed fetches, it
 // also returns a flag whether empty receipts were queued requiring importing.
 func (q *queue) ReserveReceipts(p *peer, count int) (*fetchRequest, bool, error) {
-	noop := func(header *types.Header) bool {
+	isNoop := func(header *types.Header) bool {
 		return header.ReceiptHash == types.EmptyRootHash
 	}
-	return q.reserveHeaders(p, count, q.receiptTaskPool, q.receiptTaskQueue, q.receiptPendPool, q.receiptDonePool, noop)
+	q.lock.Lock()
+	defer q.lock.Unlock()
+
+	return q.reserveHeaders(p, count, q.receiptTaskPool, q.receiptTaskQueue, q.receiptPendPool, q.receiptDonePool, isNoop)
 }
 
 // reserveHeaders reserves a set of data download operations for a given peer,
 // skipping any previously failed ones. This method is a generic version used
 // by the individual special reservation functions.
+//
+// Note, this method expects the queue lock to be already held for writing. The
+// reason the lock is not obtained in here is because the parameters already need
+// to access the queue, so they already need a lock anyway.
 func (q *queue) reserveHeaders(p *peer, count int, taskPool map[common.Hash]*types.Header, taskQueue *prque.Prque,
-	pendPool map[string]*fetchRequest, donePool map[common.Hash]struct{}, noop func(*types.Header) bool) (*fetchRequest, bool, error) {
+	pendPool map[string]*fetchRequest, donePool map[common.Hash]struct{}, isNoop func(*types.Header) bool) (*fetchRequest, bool, error) {
-	q.lock.Lock()
-	defer q.lock.Unlock()
-
 	// Short circuit if the pool has been depleted, or if the peer's already
 	// downloading something (sanity check not to corrupt state)
 	if taskQueue.Empty() {
@@ -537,7 +558,7 @@ func (q *queue) reserveHeaders(p *peer, count int, taskPool map[common.Hash]*typ
 	for proc := 0; proc < space && len(send) < count && !taskQueue.Empty(); proc++ {
 		header := taskQueue.PopItem().(*types.Header)
 
-		// If we're the first to request this task, initialize the result container
+		// If we're the first to request this task, initialise the result container
 		index := int(header.Number.Int64() - int64(q.resultOffset))
 		if index >= len(q.resultCache) || index < 0 {
 			return nil, false, errInvalidChain
@@ -553,7 +574,7 @@ func (q *queue) reserveHeaders(p *peer, count int, taskPool map[common.Hash]*typ
 			}
 		}
 		// If this fetch task is a noop, skip this fetch operation
-		if noop(header) {
+		if isNoop(header) {
 			donePool[header.Hash()] = struct{}{}
 			delete(taskPool, header.Hash())
 
@@ -562,7 +583,7 @@ func (q *queue) reserveHeaders(p *peer, count int, taskPool map[common.Hash]*typ
 			progress = true
 			continue
 		}
-		// Otherwise if not a known unknown block, add to the retrieve list
+		// Otherwise unless the peer is known not to have the data, add to the retrieve list
 		if p.ignored.Has(header.Hash()) {
 			skip = append(skip, header)
 		} else {
@@ -655,35 +676,48 @@ func (q *queue) Revoke(peerId string) {
 }
 
 // ExpireBlocks checks for in flight requests that exceeded a timeout allowance,
-// canceling them and returning the responsible peers for penalization.
+// canceling them and returning the responsible peers for penalisation.
 func (q *queue) ExpireBlocks(timeout time.Duration) []string {
+	q.lock.Lock()
+	defer q.lock.Unlock()
+
 	return q.expire(timeout, q.blockPendPool, q.hashQueue, blockTimeoutMeter)
 }
 
 // ExpireBodies checks for in flight block body requests that exceeded a timeout
-// allowance, canceling them and returning the responsible peers for penalization.
+// allowance, canceling them and returning the responsible peers for penalisation.
 func (q *queue) ExpireBodies(timeout time.Duration) []string {
+	q.lock.Lock()
+	defer q.lock.Unlock()
+
 	return q.expire(timeout, q.blockPendPool, q.blockTaskQueue, bodyTimeoutMeter)
 }
 
 // ExpireReceipts checks for in flight receipt requests that exceeded a timeout
-// allowance, canceling them and returning the responsible peers for penalization.
+// allowance, canceling them and returning the responsible peers for penalisation.
 func (q *queue) ExpireReceipts(timeout time.Duration) []string {
+	q.lock.Lock()
+	defer q.lock.Unlock()
+
 	return q.expire(timeout, q.receiptPendPool, q.receiptTaskQueue, receiptTimeoutMeter)
 }
 
 // ExpireNodeData checks for in flight node data requests that exceeded a timeout
-// allowance, canceling them and returning the responsible peers for penalization.
+// allowance, canceling them and returning the responsible peers for penalisation.
 func (q *queue) ExpireNodeData(timeout time.Duration) []string {
+	q.lock.Lock()
+	defer q.lock.Unlock()
+
 	return q.expire(timeout, q.statePendPool, q.stateTaskQueue, stateTimeoutMeter)
 }
 
 // expire is the generic check that move expired tasks from a pending pool back
 // into a task pool, returning all entities caught with expired tasks.
+//
+// Note, this method expects the queue lock to be already held for writing. The
+// reason the lock is not obtained in here is because the parameters already need
+// to access the queue, so they already need a lock anyway.
 func (q *queue) expire(timeout time.Duration, pendPool map[string]*fetchRequest, taskQueue *prque.Prque, timeoutMeter metrics.Meter) []string {
-	q.lock.Lock()
-	defer q.lock.Unlock()
-
 	// Iterate over the expired requests and return each to the queue
 	peers := []string{}
 	for id, request := range pendPool {
@@ -764,7 +798,7 @@ func (q *queue) DeliverBlocks(id string, blocks []*types.Block) error {
 	case len(errs) == 1 && (errs[0] == errInvalidChain || errs[0] == errInvalidBlock):
 		return errs[0]
 
-	case len(errs) == len(request.Headers):
+	case len(errs) == len(blocks):
 		return errStaleDelivery
 
 	default:
@@ -774,6 +808,9 @@ func (q *queue) DeliverBlocks(id string, blocks []*types.Block) error {
 
 // DeliverBodies injects a block body retrieval response into the results queue.
 func (q *queue) DeliverBodies(id string, txLists [][]*types.Transaction, uncleLists [][]*types.Header) error {
+	q.lock.Lock()
+	defer q.lock.Unlock()
+
 	reconstruct := func(header *types.Header, index int, result *fetchResult) error {
 		if types.DeriveSha(types.Transactions(txLists[index])) != header.TxHash || types.CalcUncleHash(uncleLists[index]) != header.UncleHash {
 			return errInvalidBody
@@ -787,6 +824,9 @@ func (q *queue) DeliverBodies(id string, txLists [][]*types.Transaction, uncleLi
 
 // DeliverReceipts injects a receipt retrieval response into the results queue.
 func (q *queue) DeliverReceipts(id string, receiptList [][]*types.Receipt) error {
+	q.lock.Lock()
+	defer q.lock.Unlock()
+
 	reconstruct := func(header *types.Header, index int, result *fetchResult) error {
 		if types.DeriveSha(types.Receipts(receiptList[index])) != header.ReceiptHash {
 			return errInvalidReceipt
@@ -798,11 +838,12 @@ func (q *queue) DeliverReceipts(id string, receiptList [][]*types.Receipt) error
 }
 
 // deliver injects a data retrieval response into the results queue.
+//
+// Note, this method expects the queue lock to be already held for writing. The
+// reason the lock is not obtained in here is because the parameters already need
+// to access the queue, so they already need a lock anyway.
 func (q *queue) deliver(id string, taskPool map[common.Hash]*types.Header, taskQueue *prque.Prque, pendPool map[string]*fetchRequest,
 	donePool map[common.Hash]struct{}, reqTimer metrics.Timer, results int, reconstruct func(header *types.Header, index int, result *fetchResult) error) error {
-	q.lock.Lock()
-	defer q.lock.Unlock()
-
 	// Short circuit if the data was never requested
 	request := pendPool[id]
 	if request == nil {
@@ -855,7 +896,7 @@ func (q *queue) deliver(id string, taskPool map[common.Hash]*types.Header, taskQ
 	case len(errs) == 1 && (errs[0] == errInvalidChain || errs[0] == errInvalidBody || errs[0] == errInvalidReceipt):
 		return errs[0]
 
-	case len(errs) == len(request.Headers):
+	case len(errs) == results:
 		return errStaleDelivery
 
 	default:
@@ -876,7 +917,7 @@ func (q *queue) DeliverNodeData(id string, data [][]byte, callback func(error, i
 	stateReqTimer.UpdateSince(request.Time)
 	delete(q.statePendPool, id)
 
-	// If no data was retrieved, mark them as unavailable for the origin peer
+	// If no data was retrieved, mark their hashes as unavailable for the origin peer
 	if len(data) == 0 {
 		for hash, _ := range request.Hashes {
 			request.Peer.ignored.Add(hash)

eth/fetcher/fetcher.go

@@ -142,6 +142,8 @@ type Fetcher struct {
 	dropPeer       peerDropFn         // Drops a peer for misbehaving
 
 	// Testing hooks
+	announceChangeHook func(common.Hash, bool) // Method to call upon adding or deleting a hash from the announce list
+	queueChangeHook    func(common.Hash, bool) // Method to call upon adding or deleting a block from the import queue
 	fetchingHook       func([]common.Hash)     // Method to call upon starting a block (eth/61) or header (eth/62) fetch
 	completingHook     func([]common.Hash)     // Method to call upon starting a block body fetch (eth/62)
 	importedHook       func(*types.Block)      // Method to call upon successful block import (both eth/61 and eth/62)
@@ -324,11 +326,16 @@ func (f *Fetcher) loop() {
 		height := f.chainHeight()
 		for !f.queue.Empty() {
 			op := f.queue.PopItem().(*inject)
-
+			if f.queueChangeHook != nil {
+				f.queueChangeHook(op.block.Hash(), false)
+			}
 			// If too high up the chain or phase, continue later
 			number := op.block.NumberU64()
 			if number > height+1 {
 				f.queue.Push(op, -float32(op.block.NumberU64()))
+				if f.queueChangeHook != nil {
+					f.queueChangeHook(op.block.Hash(), true)
+				}
 				break
 			}
 			// Otherwise if fresh and still unknown, try and import
@@ -372,6 +379,9 @@ func (f *Fetcher) loop() {
 			}
 			f.announces[notification.origin] = count
 			f.announced[notification.hash] = append(f.announced[notification.hash], notification)
+			if f.announceChangeHook != nil && len(f.announced[notification.hash]) == 1 {
+				f.announceChangeHook(notification.hash, true)
+			}
 			if len(f.announced) == 1 {
 				f.rescheduleFetch(fetchTimer)
 			}
@@ -714,7 +724,9 @@ func (f *Fetcher) enqueue(peer string, block *types.Block) {
 		f.queues[peer] = count
 		f.queued[hash] = op
 		f.queue.Push(op, -float32(block.NumberU64()))
-
+		if f.queueChangeHook != nil {
+			f.queueChangeHook(op.block.Hash(), true)
+		}
 		if glog.V(logger.Debug) {
 			glog.Infof("Peer %s: queued block #%d [%x…], total %v", peer, block.NumberU64(), hash.Bytes()[:4], f.queue.Size())
 		}
@@ -781,7 +793,9 @@ func (f *Fetcher) forgetHash(hash common.Hash) {
 		}
 	}
 	delete(f.announced, hash)
-
+	if f.announceChangeHook != nil {
+		f.announceChangeHook(hash, false)
+	}
 	// Remove any pending fetches and decrement the DOS counters
 	if announce := f.fetching[hash]; announce != nil {
 		f.announces[announce.origin]--

eth/fetcher/fetcher_test.go

@@ -145,6 +145,9 @@ func (f *fetcherTester) insertChain(blocks types.Blocks) (int, error) {
 // dropPeer is an emulator for the peer removal, simply accumulating the various
 // peers dropped by the fetcher.
 func (f *fetcherTester) dropPeer(peer string) {
+	f.lock.Lock()
+	defer f.lock.Unlock()
+
 	f.drops[peer] = true
 }
 
@@ -608,8 +611,11 @@ func TestDistantPropagationDiscarding(t *testing.T) {
 
 	// Create a tester and simulate a head block being the middle of the above chain
 	tester := newTester()
+
+	tester.lock.Lock()
 	tester.hashes = []common.Hash{head}
 	tester.blocks = map[common.Hash]*types.Block{head: blocks[head]}
+	tester.lock.Unlock()
 
 	// Ensure that a block with a lower number than the threshold is discarded
 	tester.fetcher.Enqueue("lower", blocks[hashes[low]])
@@ -641,8 +647,11 @@ func testDistantAnnouncementDiscarding(t *testing.T, protocol int) {
 
 	// Create a tester and simulate a head block being the middle of the above chain
 	tester := newTester()
+
+	tester.lock.Lock()
 	tester.hashes = []common.Hash{head}
 	tester.blocks = map[common.Hash]*types.Block{head: blocks[head]}
+	tester.lock.Unlock()
 
 	headerFetcher := tester.makeHeaderFetcher(blocks, -gatherSlack)
 	bodyFetcher := tester.makeBodyFetcher(blocks, 0)
@@ -687,14 +696,22 @@ func testInvalidNumberAnnouncement(t *testing.T, protocol int) {
 	tester.fetcher.Notify("bad", hashes[0], 2, time.Now().Add(-arriveTimeout), nil, headerFetcher, bodyFetcher)
 	verifyImportEvent(t, imported, false)
 
-	if !tester.drops["bad"] {
+	tester.lock.RLock()
+	dropped := tester.drops["bad"]
+	tester.lock.RUnlock()
+
+	if !dropped {
 		t.Fatalf("peer with invalid numbered announcement not dropped")
 	}
 	// Make sure a good announcement passes without a drop
 	tester.fetcher.Notify("good", hashes[0], 1, time.Now().Add(-arriveTimeout), nil, headerFetcher, bodyFetcher)
 	verifyImportEvent(t, imported, true)
 
-	if tester.drops["good"] {
+	tester.lock.RLock()
+	dropped = tester.drops["good"]
+	tester.lock.RUnlock()
+
+	if dropped {
 		t.Fatalf("peer with valid numbered announcement dropped")
 	}
 	verifyImportDone(t, imported)
@@ -752,9 +769,15 @@ func testHashMemoryExhaustionAttack(t *testing.T, protocol int) {
 	// Create a tester with instrumented import hooks
 	tester := newTester()
 
-	imported := make(chan *types.Block)
+	imported, announces := make(chan *types.Block), int32(0)
 	tester.fetcher.importedHook = func(block *types.Block) { imported <- block }
-
+	tester.fetcher.announceChangeHook = func(hash common.Hash, added bool) {
+		if added {
+			atomic.AddInt32(&announces, 1)
+		} else {
+			atomic.AddInt32(&announces, -1)
+		}
+	}
 	// Create a valid chain and an infinite junk chain
 	targetBlocks := hashLimit + 2*maxQueueDist
 	hashes, blocks := makeChain(targetBlocks, 0, genesis)
@@ -782,8 +805,8 @@ func testHashMemoryExhaustionAttack(t *testing.T, protocol int) {
 			tester.fetcher.Notify("attacker", attack[i], 1 /* don't distance drop */, time.Now(), nil, attackerHeaderFetcher, attackerBodyFetcher)
 		}
 	}
-	if len(tester.fetcher.announced) != hashLimit+maxQueueDist {
+	if count := atomic.LoadInt32(&announces); count != hashLimit+maxQueueDist {
-		t.Fatalf("queued announce count mismatch: have %d, want %d", len(tester.fetcher.announced), hashLimit+maxQueueDist)
+		t.Fatalf("queued announce count mismatch: have %d, want %d", count, hashLimit+maxQueueDist)
 	}
 	// Wait for fetches to complete
 	verifyImportCount(t, imported, maxQueueDist)
@@ -807,9 +830,15 @@ func TestBlockMemoryExhaustionAttack(t *testing.T) {
 	// Create a tester with instrumented import hooks
 	tester := newTester()
 
-	imported := make(chan *types.Block)
+	imported, enqueued := make(chan *types.Block), int32(0)
 	tester.fetcher.importedHook = func(block *types.Block) { imported <- block }
-
+	tester.fetcher.queueChangeHook = func(hash common.Hash, added bool) {
+		if added {
+			atomic.AddInt32(&enqueued, 1)
+		} else {
+			atomic.AddInt32(&enqueued, -1)
+		}
+	}
 	// Create a valid chain and a batch of dangling (but in range) blocks
 	targetBlocks := hashLimit + 2*maxQueueDist
 	hashes, blocks := makeChain(targetBlocks, 0, genesis)
@@ -825,7 +854,7 @@ func TestBlockMemoryExhaustionAttack(t *testing.T) {
 		tester.fetcher.Enqueue("attacker", block)
 	}
 	time.Sleep(200 * time.Millisecond)
-	if queued := tester.fetcher.queue.Size(); queued != blockLimit {
+	if queued := atomic.LoadInt32(&enqueued); queued != blockLimit {
 		t.Fatalf("queued block count mismatch: have %d, want %d", queued, blockLimit)
 	}
 	// Queue up a batch of valid blocks, and check that a new peer is allowed to do so
@@ -833,7 +862,7 @@ func TestBlockMemoryExhaustionAttack(t *testing.T) {
 		tester.fetcher.Enqueue("valid", blocks[hashes[len(hashes)-3-i]])
 	}
 	time.Sleep(100 * time.Millisecond)
-	if queued := tester.fetcher.queue.Size(); queued != blockLimit+maxQueueDist-1 {
+	if queued := atomic.LoadInt32(&enqueued); queued != blockLimit+maxQueueDist-1 {
 		t.Fatalf("queued block count mismatch: have %d, want %d", queued, blockLimit+maxQueueDist-1)
 	}
 	// Insert the missing piece (and sanity check the import)

eth/handler.go

@@ -103,7 +103,7 @@ func NewProtocolManager(fastSync bool, networkId int, mux *event.TypeMux, txpool
 		if fastSync && version < eth63 {
 			continue
 		}
-		// Compatible, initialize the sub-protocol
+		// Compatible; initialise the sub-protocol
 		version := version // Closure for the run
 		manager.SubProtocols = append(manager.SubProtocols, p2p.Protocol{
 			Name:    "eth",

eth/metrics.go

@@ -101,7 +101,7 @@ func (rw *meteredMsgReadWriter) ReadMsg() (p2p.Msg, error) {
 		packets, traffic = reqBlockInPacketsMeter, reqBlockInTrafficMeter
 
 	case rw.version >= eth62 && msg.Code == BlockHeadersMsg:
-		packets, traffic = reqBlockInPacketsMeter, reqBlockInTrafficMeter
+		packets, traffic = reqHeaderInPacketsMeter, reqHeaderInTrafficMeter
 	case rw.version >= eth62 && msg.Code == BlockBodiesMsg:
 		packets, traffic = reqBodyInPacketsMeter, reqBodyInTrafficMeter
 

trie/sync.go

@@ -31,7 +31,7 @@ type request struct {
 	object *node       // Target node to populate with retrieved data (hashnode originally)
 
 	parents []*request // Parent state nodes referencing this entry (notify all upon completion)
-	depth   int        // Depth level within the trie the node is located to prioritize DFS
+	depth   int        // Depth level within the trie the node is located to prioritise DFS
 	deps    int        // Number of dependencies before allowed to commit this node
 
 	callback TrieSyncLeafCallback // Callback to invoke if a leaf node it reached on this branch