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Make DisconnectBlock fault-tolerant

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This commit is contained in:
Pieter Wuille 2012-12-30 15:29:39 +01:00
parent ea9788517b
commit 2cbd71da06
2 changed files with 42 additions and 20 deletions
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55
src/main.cpp
View file

@ -1464,23 +1464,32 @@ bool CTransaction::ClientCheckInputs() const
bool CBlock::DisconnectBlock(CBlockIndex *pindex, CCoinsViewCache &view)
bool CBlock::DisconnectBlock(CBlockIndex *pindex, CCoinsViewCache &view, bool *pfClean)
{
assert(pindex == view.GetBestBlock());
if (pfClean)
*pfClean = false;
bool fClean = true;
CBlockUndo blockUndo;
{
CDiskBlockPos pos = pindex->GetUndoPos();
if (pos.IsNull())
return error("DisconnectBlock() : no undo data available");
FILE *file = OpenUndoFile(pos, true);
if (file == NULL)
return error("DisconnectBlock() : undo file not available");
CAutoFile fileUndo(file, SER_DISK, CLIENT_VERSION);
fileUndo >> blockUndo;
CAutoFile fileUndo(OpenUndoFile(pos, true), SER_DISK, CLIENT_VERSION);
if (!fileUndo)
return error("DisconnectBlock() : cannot open undo file");
try {
fileUndo >> blockUndo;
} catch(std::exception &e) {
return error("DisconnectBlock() : deserialize or I/O error reading udno data");
}
}
assert(blockUndo.vtxundo.size() + 1 == vtx.size());
if (blockUndo.vtxundo.size() + 1 != vtx.size())
return error("DisconnectBlock() : block and undo data inconsistent");
// undo transactions in reverse order
for (int i = vtx.size() - 1; i >= 0; i--) {
@ -1488,13 +1497,15 @@ bool CBlock::DisconnectBlock(CBlockIndex *pindex, CCoinsViewCache &view)
uint256 hash = tx.GetHash();
// check that all outputs are available
if (!view.HaveCoins(hash))
return error("DisconnectBlock() : outputs still spent? database corrupted");
if (!view.HaveCoins(hash)) {
fClean = fClean && error("DisconnectBlock() : outputs still spent? database corrupted");
view.SetCoins(hash, CCoins());
}
CCoins &outs = view.GetCoins(hash);
CCoins outsBlock = CCoins(tx, pindex->nHeight);
if (outs != outsBlock)
return error("DisconnectBlock() : added transaction mismatch? database corrupted");
fClean = fClean && error("DisconnectBlock() : added transaction mismatch? database corrupted");
// remove outputs
outs = CCoins();
@ -1502,24 +1513,27 @@ bool CBlock::DisconnectBlock(CBlockIndex *pindex, CCoinsViewCache &view)
// restore inputs
if (i > 0) { // not coinbases
const CTxUndo &txundo = blockUndo.vtxundo[i-1];
assert(txundo.vprevout.size() == tx.vin.size());
if (txundo.vprevout.size() != tx.vin.size())
return error("DisconnectBlock() : transaction and undo data inconsistent");
for (unsigned int j = tx.vin.size(); j-- > 0;) {
const COutPoint &out = tx.vin[j].prevout;
const CTxInUndo &undo = txundo.vprevout[j];
CCoins coins;
view.GetCoins(out.hash, coins); // this can fail if the prevout was already entirely spent
if (coins.IsPruned()) {
if (undo.nHeight == 0)
return error("DisconnectBlock() : undo data doesn't contain tx metadata? database corrupted");
if (undo.nHeight != 0) {
// undo data contains height: this is the last output of the prevout tx being spent
if (!coins.IsPruned())
fClean = fClean && error("DisconnectBlock() : undo data overwriting existing transaction");
coins = CCoins();
coins.fCoinBase = undo.fCoinBase;
coins.nHeight = undo.nHeight;
coins.nVersion = undo.nVersion;
} else {
if (undo.nHeight != 0)
return error("DisconnectBlock() : undo data contains unneeded tx metadata? database corrupted");
if (coins.IsPruned())
fClean = fClean && error("DisconnectBlock() : undo data adding output to missing transaction");
}
if (coins.IsAvailable(out.n))
return error("DisconnectBlock() : prevout output not spent? database corrupted");
fClean = fClean && error("DisconnectBlock() : undo data overwriting existing output");
if (coins.vout.size() < out.n+1)
coins.vout.resize(out.n+1);
coins.vout[out.n] = undo.txout;
@ -1532,7 +1546,12 @@ bool CBlock::DisconnectBlock(CBlockIndex *pindex, CCoinsViewCache &view)
// move best block pointer to prevout block
view.SetBestBlock(pindex->pprev);
return true;
if (pfClean) {
*pfClean = fClean;
return true;
} else {
return fClean;
}
}
void static FlushBlockFile()

7
src/main.h
View file

@ -1305,8 +1305,11 @@ public:
}
// Undo the effects of this block (with given index) on the UTXO set represented by coins
bool DisconnectBlock(CBlockIndex *pindex, CCoinsViewCache &coins);
/** Undo the effects of this block (with given index) on the UTXO set represented by coins.
* In case pfClean is provided, operation will try to be tolerant about errors, and *pfClean
* will be true if no problems were found. Otherwise, the return value will be false in case
* of problems. Note that in any case, coins may be modified. */
bool DisconnectBlock(CBlockIndex *pindex, CCoinsViewCache &coins, bool *pfClean = NULL);
// Apply the effects of this block (with given index) on the UTXO set represented by coins
bool ConnectBlock(CBlockIndex *pindex, CCoinsViewCache &coins, bool fJustCheck=false);