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core: fixed chain reorg during splits

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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
Download Patch File Download Diff File Expand all files Collapse all files

58
core/chain_manager.go
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@ -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() {