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core: fixed chain reorg during splits 

Chain reorgs weren't properly handled when a chain was further ahead.
Previously we'd end up with mixed chains in our canonical numbering
sequence. Added test for this type of forking.

```
     /-o-o-o   A
o-C-+
     \-o-o-o-o B
```

Ends up with with C A1, A2, A3, B4
This commit is contained in:
obscuren 2015-04-29 12:43:24 +02:00
parent af73d1d682
commit 4e07967711
2 changed files with 83 additions and 27 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

58
core/chain_manager.go
View File

@ -74,9 +74,8 @@ type ChainManager struct {
eventMux *event.TypeMux
genesisBlock *types.Block
// Last known total difficulty
mu sync.RWMutex
tsmu sync.RWMutex
insertMu sync.Mutex
mu sync.RWMutex
tsmu sync.RWMutex
td *big.Int
currentBlock *types.Block
@ -321,6 +320,7 @@ func (bc *ChainManager) ResetWithGenesisBlock(gb *types.Block) {
bc.insert(bc.genesisBlock)
bc.currentBlock = bc.genesisBlock
bc.makeCache()
bc.td = gb.Difficulty()
}
// Export writes the active chain to the given writer.
@ -348,8 +348,6 @@ func (self *ChainManager) Export(w io.Writer) error {
func (bc *ChainManager) insert(block *types.Block) {
key := append(blockNumPre, block.Number().Bytes()...)
bc.blockDb.Put(key, block.Hash().Bytes())
// Push block to cache
bc.cache.Push(block)
bc.blockDb.Put([]byte("LastBlock"), block.Hash().Bytes())
bc.currentBlock = block
@ -360,6 +358,8 @@ func (bc *ChainManager) write(block *types.Block) {
enc, _ := rlp.EncodeToBytes((*types.StorageBlock)(block))
key := append(blockHashPre, block.Hash().Bytes()...)
bc.blockDb.Put(key, enc)
// Push block to cache
bc.cache.Push(block)
}
// Accessors
@ -498,9 +498,6 @@ func (self *ChainManager) procFutureBlocks() {
}
func (self *ChainManager) InsertChain(chain types.Blocks) error {
self.insertMu.Lock()
defer self.insertMu.Unlock()
// A queued approach to delivering events. This is generally faster than direct delivery and requires much less mutex acquiring.
var (
queue = make([]interface{}, len(chain))
@ -557,16 +554,17 @@ func (self *ChainManager) InsertChain(chain types.Blocks) error {
// Compare the TD of the last known block in the canonical chain to make sure it's greater.
// At this point it's possible that a different chain (fork) becomes the new canonical chain.
if block.Td.Cmp(self.td) > 0 {
//if block.Header().Number.Cmp(new(big.Int).Add(cblock.Header().Number, common.Big1)) < 0 {
if block.Number().Cmp(cblock.Number()) <= 0 {
// Check for chain forks. If H(block.num - 1) != block.parent, we're on a fork and need to do some merging
if previous := self.getBlockByNumber(block.NumberU64() - 1); previous.Hash() != block.ParentHash() {
chash := cblock.Hash()
hash := block.Hash()
if glog.V(logger.Info) {
glog.Infof("Split detected. New head #%v (%x) TD=%v, was #%v (%x) TD=%v\n", block.Header().Number, hash[:4], block.Td, cblock.Header().Number, chash[:4], self.td)
}
// during split we merge two different chains and create the new canonical chain
self.merge(self.getBlockByNumber(block.NumberU64()), block)
self.merge(previous, block)
queue[i] = ChainSplitEvent{block, logs}
queueEvent.splitCount++
@ -592,16 +590,19 @@ func (self *ChainManager) InsertChain(chain types.Blocks) error {
glog.Infof("inserted block #%d (%d TXs %d UNCs) (%x...)\n", block.Number(), len(block.Transactions()), len(block.Uncles()), block.Hash().Bytes()[0:4])
}
} else {
if glog.V(logger.Detail) {
glog.Infof("inserted forked block #%d (%d TXs %d UNCs) (%x...)\n", block.Number(), len(block.Transactions()), len(block.Uncles()), block.Hash().Bytes()[0:4])
}
queue[i] = ChainSideEvent{block, logs}
queueEvent.sideCount++
}
self.futureBlocks.Delete(block.Hash())
}
self.mu.Unlock()
stats.processed++
self.futureBlocks.Delete(block.Hash())
}
if (stats.queued > 0 || stats.processed > 0) && bool(glog.V(logger.Info)) {
@ -615,33 +616,38 @@ func (self *ChainManager) InsertChain(chain types.Blocks) error {
return nil
}
// merge takes two blocks, an old chain and a new chain and will reconstruct the blocks and inserts them
// diff takes two blocks, an old chain and a new chain and will reconstruct the blocks and inserts them
// to be part of the new canonical chain.
func (self *ChainManager) merge(oldBlock, newBlock *types.Block) {
func (self *ChainManager) diff(oldBlock, newBlock *types.Block) types.Blocks {
glog.V(logger.Debug).Infof("Applying diff to %x & %x\n", oldBlock.Hash().Bytes()[:4], newBlock.Hash().Bytes()[:4])
var oldChain, newChain types.Blocks
// First find the split (common ancestor) so we can perform an adequate merge
var newChain types.Blocks
// first find common number
for newBlock = newBlock; newBlock.NumberU64() != oldBlock.NumberU64(); newBlock = self.GetBlock(newBlock.ParentHash()) {
newChain = append(newChain, newBlock)
}
glog.V(logger.Debug).Infoln("Found common number", newBlock.Number())
for {
oldBlock, newBlock = self.GetBlock(oldBlock.ParentHash()), self.GetBlock(newBlock.ParentHash())
if oldBlock.Hash() == newBlock.Hash() {
break
}
oldChain = append(oldChain, oldBlock)
newChain = append(newChain, newBlock)
oldBlock, newBlock = self.GetBlock(oldBlock.ParentHash()), self.GetBlock(newBlock.ParentHash())
}
return newChain
}
// merge merges two different chain to the new canonical chain
func (self *ChainManager) merge(oldBlock, newBlock *types.Block) {
newChain := self.diff(oldBlock, newBlock)
// insert blocks
for _, block := range newChain {
self.insert(block)
}
if glog.V(logger.Detail) {
for i, oldBlock := range oldChain {
glog.Infof("- %.10v = %x\n", oldBlock.Number(), oldBlock.Hash())
glog.Infof("+ %.10v = %x\n", newChain[i].Number(), newChain[i].Hash())
}
}
}
func (self *ChainManager) update() {

52
core/chain_manager_test.go
View File

@ -9,6 +9,7 @@ import (
"strconv"
"testing"
"github.com/ethereum/go-ethereum/core/state"
"github.com/ethereum/go-ethereum/core/types"
"github.com/ethereum/go-ethereum/ethdb"
"github.com/ethereum/go-ethereum/event"
@ -56,12 +57,14 @@ func testFork(t *testing.T, bman *BlockProcessor, i, N int, f func(td1, td2 *big
}
// Compare difficulties
f(tdpre, td)
// Loop over parents making sure reconstruction is done properly
}
func printChain(bc *ChainManager) {
for i := bc.CurrentBlock().Number().Uint64(); i > 0; i-- {
b := bc.GetBlockByNumber(uint64(i))
fmt.Printf("\t%x\n", b.Hash())
fmt.Printf("\t%x %v\n", b.Hash(), b.Difficulty())
}
}
@ -344,3 +347,50 @@ func TestGetAncestors(t *testing.T) {
ancestors := chainMan.GetAncestors(chain[len(chain)-1], 4)
fmt.Println(ancestors)
}
type bproc struct{}
func (bproc) Process(*types.Block) (state.Logs, error) { return nil, nil }
func makeChainWithDiff(genesis *types.Block, d []int, seed byte) []*types.Block {
var chain []*types.Block
for i, difficulty := range d {
header := &types.Header{Number: big.NewInt(int64(i + 1)), Difficulty: big.NewInt(int64(difficulty))}
block := types.NewBlockWithHeader(header)
copy(block.HeaderHash[:2], []byte{byte(i + 1), seed})
if i == 0 {
block.ParentHeaderHash = genesis.Hash()
} else {
copy(block.ParentHeaderHash[:2], []byte{byte(i), seed})
}
chain = append(chain, block)
}
return chain
}
func TestReorg(t *testing.T) {
db, _ := ethdb.NewMemDatabase()
var eventMux event.TypeMux
genesis := GenesisBlock(db)
bc := &ChainManager{blockDb: db, stateDb: db, genesisBlock: genesis, eventMux: &eventMux}
bc.cache = NewBlockCache(100)
bc.futureBlocks = NewBlockCache(100)
bc.processor = bproc{}
bc.ResetWithGenesisBlock(genesis)
bc.txState = state.ManageState(bc.State())
chain1 := makeChainWithDiff(genesis, []int{1, 2, 4}, 10)
chain2 := makeChainWithDiff(genesis, []int{1, 2, 3, 4}, 11)
bc.InsertChain(chain1)
bc.InsertChain(chain2)
prev := bc.CurrentBlock()
for block := bc.GetBlockByNumber(bc.CurrentBlock().NumberU64() - 1); block.NumberU64() != 0; prev, block = block, bc.GetBlockByNumber(block.NumberU64()-1) {
if prev.ParentHash() != block.Hash() {
t.Errorf("parent hash mismatch %x - %x", prev.ParentHash(), block.Hash())
}
}
}