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blockchain: Add ReconsiderBlock() #2181

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blockchain: Add ReconsiderBlock() #2181

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597b68c
blockchain, workmath: refactor functions to workmath package
kcalvinalvin Apr 2, 2024
337d7f6
fullblocktests, testhelper: refactor out spendableOut
kcalvinalvin Apr 2, 2024
d4644df
fullblocktests, testhelper: move solveBlock to testhelper
kcalvinalvin Apr 2, 2024
62790ac
fullblocktests, testhelper: move opTrueScript and lowFee to testhelper
kcalvinalvin Apr 2, 2024
9093243
fullblocktests, testhelper: move uniqueOpReturnScript to testhelper
kcalvinalvin Apr 2, 2024
59c7d10
fullblocktests, testhelper: move standardCoinbaseScript to testhelper
kcalvinalvin Apr 2, 2024
8ab27b9
fullblocktests, testhelper: move createCoinbaseTx to testhelper
kcalvinalvin Apr 2, 2024
5df1437
fullblocktests, testhelper: move createSpendTx to testhelper
kcalvinalvin Apr 2, 2024
ea39fe0
blockchain: add block generating functions in test code
kcalvinalvin Apr 2, 2024
635ae68
blockchain: Add InvalidateBlock() method to BlockChain
kcalvinalvin Apr 2, 2024
c14546b
blockchain: Refactor reorganizeChain to exclude verification
kcalvinalvin Apr 30, 2024
7c04bd8
blockchain: Add ReconsiderBlock to BlockChain
kcalvinalvin Apr 30, 2024
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251 changes: 132 additions & 119 deletions blockchain/chain.go
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Original file line number Diff line number Diff line change
Expand Up @@ -870,19 +870,128 @@ func countSpentOutputs(block *btcutil.Block) int {
//
// This function MUST be called with the chain state lock held (for writes).
func (b *BlockChain) reorganizeChain(detachNodes, attachNodes *list.List) error {
// Check first that the detach and the attach nodes are valid and they
// pass verification.
detachBlocks, attachBlocks, detachSpentTxOuts,
err := b.verifyReorganizationValidity(detachNodes, attachNodes)
if err != nil {
return err
}

// Track the old and new best chains heads.
tip := b.bestChain.Tip()
oldBest := tip
newBest := tip

// Reset the view for the actual connection code below. This is
// required because the view was previously modified when checking if
// the reorg would be successful and the connection code requires the
// view to be valid from the viewpoint of each block being disconnected.
view := NewUtxoViewpoint()
view.SetBestHash(&b.bestChain.Tip().hash)

// Disconnect blocks from the main chain.
for i, e := 0, detachNodes.Front(); e != nil; i, e = i+1, e.Next() {
n := e.Value.(*blockNode)
block := detachBlocks[i]

// Load all of the utxos referenced by the block that aren't
// already in the view.
err := view.fetchInputUtxos(b.utxoCache, block)
if err != nil {
return err
}

// Update the view to unspend all of the spent txos and remove
// the utxos created by the block.
err = view.disconnectTransactions(b.db, block,
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Style nit, can reflow as:

err = view.disconnectTransactions(
    b.db, block, detachSpentTxOuts[i],
)

detachSpentTxOuts[i])
if err != nil {
return err
}

// Update the database and chain state. The cache will be flushed
// here before the utxoview modifications happen to the database.
err = b.disconnectBlock(n, block, view)
if err != nil {
return err
}

newBest = n.parent
}

// Set the fork point only if there are nodes to attach since otherwise
// blocks are only being disconnected and thus there is no fork point.
var forkNode *blockNode
if attachNodes.Len() > 0 {
forkNode = newBest
}

// Connect the new best chain blocks using the utxocache directly. It's more
// efficient and since we already checked that the blocks are correct and that
// the transactions connect properly, it's ok to access the cache. If we suddenly
// crash here, we are able to recover as well.
for i, e := 0, attachNodes.Front(); e != nil; i, e = i+1, e.Next() {
n := e.Value.(*blockNode)
block := attachBlocks[i]

// Update the cache to mark all utxos referenced by the block
// as spent and add all transactions being created by this block
// to it. Also, provide an stxo slice so the spent txout
// details are generated.
stxos := make([]SpentTxOut, 0, countSpentOutputs(block))
err = b.utxoCache.connectTransactions(block, &stxos)
if err != nil {
return err
}

// Update the database and chain state.
err = b.connectBlock(n, block, stxos)
if err != nil {
return err
}

newBest = n
}

// Log the point where the chain forked and old and new best chain
// heads.
if forkNode != nil {
log.Infof("REORGANIZE: Chain forks at %v (height %v)", forkNode.hash,
forkNode.height)
}
log.Infof("REORGANIZE: Old best chain head was %v (height %v)",
&oldBest.hash, oldBest.height)
log.Infof("REORGANIZE: New best chain head is %v (height %v)",
newBest.hash, newBest.height)

return nil
}

// verifyReorganizationValidity will verify that the disconnects and the connects
// that are in the list are able to be processed without mutating the chain.
//
// For the attach nodes, it'll check that each of the blocks are valid and will
// change the status of the block node in the list to invalid if the block fails
// to pass verification. For the detach nodes, it'll check that the blocks being
// detached and their spend journals are present on the database.
func (b *BlockChain) verifyReorganizationValidity(detachNodes, attachNodes *list.List) (
[]*btcutil.Block, []*btcutil.Block, [][]SpentTxOut, error) {

// Nothing to do if no reorganize nodes were provided.
if detachNodes.Len() == 0 && attachNodes.Len() == 0 {
return nil
return nil, nil, nil, nil
}

// Ensure the provided nodes match the current best chain.
tip := b.bestChain.Tip()
if detachNodes.Len() != 0 {
firstDetachNode := detachNodes.Front().Value.(*blockNode)
if firstDetachNode.hash != tip.hash {
return AssertError(fmt.Sprintf("reorganize nodes to detach are "+
"not for the current best chain -- first detach node %v, "+
"current chain %v", &firstDetachNode.hash, &tip.hash))
return nil, nil, nil,
AssertError(fmt.Sprintf("reorganize nodes to detach are "+
"not for the current best chain -- first detach node %v, "+
"current chain %v", &firstDetachNode.hash, &tip.hash))
}
}

Expand All @@ -891,17 +1000,14 @@ func (b *BlockChain) reorganizeChain(detachNodes, attachNodes *list.List) error
firstAttachNode := attachNodes.Front().Value.(*blockNode)
lastDetachNode := detachNodes.Back().Value.(*blockNode)
if firstAttachNode.parent.hash != lastDetachNode.parent.hash {
return AssertError(fmt.Sprintf("reorganize nodes do not have the "+
"same fork point -- first attach parent %v, last detach "+
"parent %v", &firstAttachNode.parent.hash,
&lastDetachNode.parent.hash))
return nil, nil, nil,
AssertError(fmt.Sprintf("reorganize nodes do not have the "+
"same fork point -- first attach parent %v, last detach "+
"parent %v", &firstAttachNode.parent.hash,
&lastDetachNode.parent.hash))
}
}

// Track the old and new best chains heads.
oldBest := tip
newBest := tip

// All of the blocks to detach and related spend journal entries needed
// to unspend transaction outputs in the blocks being disconnected must
// be loaded from the database during the reorg check phase below and
Expand All @@ -916,7 +1022,7 @@ func (b *BlockChain) reorganizeChain(detachNodes, attachNodes *list.List) error
// database and using that information to unspend all of the spent txos
// and remove the utxos created by the blocks.
view := NewUtxoViewpoint()
view.SetBestHash(&oldBest.hash)
view.SetBestHash(&tip.hash)
for e := detachNodes.Front(); e != nil; e = e.Next() {
n := e.Value.(*blockNode)
var block *btcutil.Block
Expand All @@ -926,19 +1032,20 @@ func (b *BlockChain) reorganizeChain(detachNodes, attachNodes *list.List) error
return err
})
if err != nil {
return err
return nil, nil, nil, err
}
if n.hash != *block.Hash() {
return AssertError(fmt.Sprintf("detach block node hash %v (height "+
"%v) does not match previous parent block hash %v", &n.hash,
n.height, block.Hash()))
return nil, nil, nil, AssertError(
fmt.Sprintf("detach block node hash %v (height "+
"%v) does not match previous parent block hash %v",
&n.hash, n.height, block.Hash()))
}

// Load all of the utxos referenced by the block that aren't
// already in the view.
err = view.fetchInputUtxos(b.utxoCache, block)
if err != nil {
return err
return nil, nil, nil, err
}

// Load all of the spent txos for the block from the spend
Expand All @@ -949,7 +1056,7 @@ func (b *BlockChain) reorganizeChain(detachNodes, attachNodes *list.List) error
return err
})
if err != nil {
return err
return nil, nil, nil, err
}

// Store the loaded block and spend journal entry for later.
Expand All @@ -958,17 +1065,8 @@ func (b *BlockChain) reorganizeChain(detachNodes, attachNodes *list.List) error

err = view.disconnectTransactions(b.db, block, stxos)
if err != nil {
return err
return nil, nil, nil, err
}

newBest = n.parent
}

// Set the fork point only if there are nodes to attach since otherwise
// blocks are only being disconnected and thus there is no fork point.
var forkNode *blockNode
if attachNodes.Len() > 0 {
forkNode = newBest
}

// Perform several checks to verify each block that needs to be attached
Expand All @@ -993,7 +1091,7 @@ func (b *BlockChain) reorganizeChain(detachNodes, attachNodes *list.List) error
return err
})
if err != nil {
return err
return nil, nil, nil, err
}

// Store the loaded block for later.
Expand All @@ -1005,14 +1103,13 @@ func (b *BlockChain) reorganizeChain(detachNodes, attachNodes *list.List) error
if b.index.NodeStatus(n).KnownValid() {
err = view.fetchInputUtxos(b.utxoCache, block)
if err != nil {
return err
return nil, nil, nil, err
}
err = view.connectTransactions(block, nil)
if err != nil {
return err
return nil, nil, nil, err
}

newBest = n
continue
}

Expand All @@ -1033,96 +1130,12 @@ func (b *BlockChain) reorganizeChain(detachNodes, attachNodes *list.List) error
b.index.SetStatusFlags(dn, statusInvalidAncestor)
}
}
return err
return nil, nil, nil, err
}
b.index.SetStatusFlags(n, statusValid)

newBest = n
}

// Flush the utxo cache for the block disconnect below. The disconnect
// code assumes that it's directly modifying the database so the cache
// will be left in an inconsistent state. It needs to be flushed beforehand
// in order for that to not happen.
err := b.db.Update(func(dbTx database.Tx) error {
return b.utxoCache.flush(dbTx, FlushRequired, b.BestSnapshot())
})
if err != nil {
return err
}

// Reset the view for the actual connection code below. This is
// required because the view was previously modified when checking if
// the reorg would be successful and the connection code requires the
// view to be valid from the viewpoint of each block being disconnected.
view = NewUtxoViewpoint()
view.SetBestHash(&b.bestChain.Tip().hash)

// Disconnect blocks from the main chain.
for i, e := 0, detachNodes.Front(); e != nil; i, e = i+1, e.Next() {
n := e.Value.(*blockNode)
block := detachBlocks[i]

// Load all of the utxos referenced by the block that aren't
// already in the view.
err := view.fetchInputUtxos(b.utxoCache, block)
if err != nil {
return err
}

// Update the view to unspend all of the spent txos and remove
// the utxos created by the block.
err = view.disconnectTransactions(b.db, block,
detachSpentTxOuts[i])
if err != nil {
return err
}

// Update the database and chain state. The cache will be flushed
// here before the utxoview modifications happen to the database.
err = b.disconnectBlock(n, block, view)
if err != nil {
return err
}
}

// Connect the new best chain blocks using the utxocache directly. It's more
// efficient and since we already checked that the blocks are correct and that
// the transactions connect properly, it's ok to access the cache. If we suddenly
// crash here, we are able to recover as well.
for i, e := 0, attachNodes.Front(); e != nil; i, e = i+1, e.Next() {
n := e.Value.(*blockNode)
block := attachBlocks[i]

// Update the cache to mark all utxos referenced by the block
// as spent and add all transactions being created by this block
// to it. Also, provide an stxo slice so the spent txout
// details are generated.
stxos := make([]SpentTxOut, 0, countSpentOutputs(block))
err = b.utxoCache.connectTransactions(block, &stxos)
if err != nil {
return err
}

// Update the database and chain state.
err = b.connectBlock(n, block, stxos)
if err != nil {
return err
}
}

// Log the point where the chain forked and old and new best chain
// heads.
if forkNode != nil {
log.Infof("REORGANIZE: Chain forks at %v (height %v)", forkNode.hash,
forkNode.height)
}
log.Infof("REORGANIZE: Old best chain head was %v (height %v)",
&oldBest.hash, oldBest.height)
log.Infof("REORGANIZE: New best chain head is %v (height %v)",
newBest.hash, newBest.height)

return nil
return detachBlocks, attachBlocks, detachSpentTxOuts, nil
}

// connectBestChain handles connecting the passed block to the chain while
Expand Down