Redo 2298

src/init.cpp

@@ -421,6 +421,7 @@ std::string HelpMessage(HelpMessageMode mode)
     strUsage += HelpMessageOpt("-reindex-chainstate", "Rebuild chain state from the currently indexed blocks");
     strUsage += HelpMessageOpt("-reindex", "Rebuild block chain index from current blk000??.dat files on startup");
     strUsage += HelpMessageOpt("-resync", "Delete blockchain folders and resync from scratch on startup");
+    strUsage += HelpMessageOpt("-rewindblockindex", "Rewind blockchain to the last checkpoint");
 #if !defined(WIN32)
     strUsage += HelpMessageOpt("-sysperms", "Create new files with system default permissions, instead of umask 077 (only effective with disabled wallet functionality)");
 #endif
@@ -1424,6 +1425,7 @@ bool AppInitMain()
 
     fReindex = gArgs.GetBoolArg("-reindex", false);
     bool fReindexChainState = gArgs.GetBoolArg("-reindex-chainstate", false);
+    bool clearWitnessCaches = false;
 
     // cache size calculations
     int64_t nTotalCache = (gArgs.GetArg("-dbcache", nDefaultDbCache) << 20);
@@ -1572,8 +1574,17 @@ bool AppInitMain()
                     }
                 }
 
+                uiInterface.InitMessage(_("Verifying blocks..."));
+
                 if (!is_coinsview_empty) {
-                    uiInterface.InitMessage(_("Verifying blocks..."));
+                    if (!fReindex && chainActive.Tip() != NULL) {
+                        uiInterface.InitMessage(_("Rewinding blocks to last checkpoint if needed..."));
+                        if (!RewindBlockIndexToLastCheckpoint(chainparams, clearWitnessCaches, gArgs.GetBoolArg("-rewindblockindex", false))) {
+                            strLoadError = _("Unable to rewind the blockchain to last checkpoint. You will need to redownload the blockchain");
+                            break;
+                        }
+                    }
+
                     CBlockIndex *tip = chainActive.Tip();
                     RPCNotifyBlockChange(true, tip);
                     if (tip && tip->nTime > GetAdjustedTime() + 2 * 60 * 60) {
@@ -1635,7 +1646,7 @@ bool AppInitMain()
 
 // ********************************************************* Step 8: Backup and Load wallet
 #ifdef ENABLE_WALLET
-    if (!InitLoadWallet())
+    if (!InitLoadWallet(clearWitnessCaches))
         return false;
 #else
     LogPrintf("No wallet compiled in!\n");

src/txdb.cpp

@@ -247,6 +247,14 @@ bool CBlockTreeDB::WriteBatchSync(const std::vector<std::pair<int, const CBlockF
     return WriteBatch(batch, true);
 }
 
+bool CBlockTreeDB::EraseBatchSync(const std::vector<const CBlockIndex*>& blockinfo) {
+    CDBBatch batch;
+    for (std::vector<const CBlockIndex*>::const_iterator it=blockinfo.begin(); it != blockinfo.end(); it++) {
+        batch.Erase(std::make_pair(DB_BLOCK_INDEX, (*it)->GetBlockHash()));
+    }
+    return WriteBatch(batch, true);
+}
+
 bool CBlockTreeDB::ReadTxIndex(const uint256& txid, CDiskTxPos& pos)
 {
     return Read(std::make_pair(DB_TXINDEX, txid), pos);

src/txdb.h

@@ -134,6 +134,7 @@ class CBlockTreeDB : public CDBWrapper
 
     bool WriteBlockIndex(const CDiskBlockIndex& blockindex);
     bool WriteBatchSync(const std::vector<std::pair<int, const CBlockFileInfo*> >& fileInfo, int nLastFile, const std::vector<const CBlockIndex*>& blockinfo);
+    bool EraseBatchSync(const std::vector<const CBlockIndex*>& blockinfo);
     bool ReadBlockFileInfo(int nFile, CBlockFileInfo& info);
     bool ReadLastBlockFile(int& nFile);
     bool WriteReindexing(bool fReindexing);

src/validation.cpp

@@ -3741,6 +3741,102 @@ bool CVerifyDB::VerifyDB(CCoinsView* coinsview, int nCheckLevel, int nCheckDepth
     return true;
 }
 
+bool RewindBlockIndexToLastCheckpoint(const CChainParams& chainparams, bool& clearWitnessCaches, bool fJustCheck)
+{
+    LOCK(cs_main);
+
+    // Get current Height and current Checkpoints
+    int nHeight = chainActive.Height();
+    const CBlockIndex* prevCheckPoint = GetLastCheckpoint();
+    const int checkPointHeight = prevCheckPoint ? prevCheckPoint->nHeight : 0;
+
+    // First load options
+    if(!fJustCheck)
+        return true;
+
+    clearWitnessCaches = true;
+    CValidationState state;
+    const int blocksToRollBack = nHeight - checkPointHeight;
+    // Iterate to start removing blocks
+    while (nHeight > checkPointHeight) {
+        if (!DisconnectTip(state, chainparams, nullptr)) {
+            return error("%s: unable to disconnect block at height %i", __func__, nHeight);
+        }
+        // Occasionally flush state to disk.
+        if (!FlushStateToDisk(state, FLUSH_STATE_PERIODIC))
+            return false;
+
+        nHeight = chainActive.Height();
+    }
+
+    // Collect blocks to be removed (blocks in mapBlockIndex must be at least BLOCK_VALID_TREE).
+    // We do this after actual disconnecting, otherwise we'll end up writing the lack of data
+    // to disk before writing the chainstate, resulting in a failure to continue if interrupted.
+    std::vector<const CBlockIndex*> vBlocks;
+    for (BlockMap::iterator it = mapBlockIndex.begin(); it != mapBlockIndex.end(); it++) {
+        CBlockIndex* pindexIter = it->second;
+        if (!chainActive.Contains(pindexIter)) {
+            // Add to the list of blocks to remove
+            vBlocks.emplace_back(pindexIter);
+            if (pindexIter == pindexBestInvalid) {
+                // Reset invalid block marker if it was pointing to this block
+                pindexBestInvalid = nullptr;
+            }
+            // Reduce validity
+            pindexIter->nStatus = std::min<unsigned int>(pindexIter->nStatus & BLOCK_VALID_MASK, BLOCK_VALID_TREE) | (pindexIter->nStatus & ~BLOCK_VALID_MASK);
+            // Remove have-data flags.
+            pindexIter->nStatus &= ~(BLOCK_HAVE_DATA | BLOCK_HAVE_UNDO);
+            // Remove storage location.
+            pindexIter->nFile = 0;
+            pindexIter->nDataPos = 0;
+            pindexIter->nUndoPos = 0;
+            // Remove various other things
+            pindexIter->nTx = 0;
+            pindexIter->nChainTx = 0;
+            pindexIter->nSequenceId = 0;
+            // Update indices
+            setBlockIndexCandidates.erase(pindexIter);
+            auto ret = mapBlocksUnlinked.equal_range(pindexIter->pprev);
+            while (ret.first != ret.second) {
+                if (ret.first->second == pindexIter) {
+                    ret.first = mapBlocksUnlinked.erase(ret.first);
+                } else {
+                    ++ret.first;
+                }
+            }
+        } else if (pindexIter->IsValid(BLOCK_VALID_TRANSACTIONS) && pindexIter->nChainTx) {
+            setBlockIndexCandidates.insert(pindexIter);
+        }
+    }
+
+    // Set pindexBestHeader to the current chain tip
+    // (since we are about to delete the block it is pointing to)
+    pindexBestHeader = chainActive.Tip();
+
+    // Erase block indices on-disk
+    if (!pblocktree->EraseBatchSync(vBlocks)) {
+        return AbortNode(state, "Failed to erase from block index database");
+    }
+
+    // Erase block indices in-memory
+    for (auto pindex : vBlocks) {
+        auto ret = mapBlockIndex.find(*pindex->phashBlock);
+        if (ret != mapBlockIndex.end()) {
+            mapBlockIndex.erase(ret);
+            delete pindex;
+        }
+    }
+
+    CheckBlockIndex();
+
+    if (!FlushStateToDisk(state, FLUSH_STATE_ALWAYS)) {
+        return false;
+    }
+
+    return true;
+}
+
+
 /** Apply the effects of a block on the utxo cache, ignoring that it may already have been applied. */
 static bool RollforwardBlock(const CBlockIndex* pindex, CCoinsViewCache& inputs, const CChainParams& params) EXCLUSIVE_LOCKS_REQUIRED(cs_main)
 {

src/validation.h

@@ -338,6 +338,9 @@ class CVerifyDB
     bool VerifyDB(CCoinsView* coinsview, int nCheckLevel, int nCheckDepth);
 };
 
+/** Rewind chain up to the last checkpoint */
+bool RewindBlockIndexToLastCheckpoint(const CChainParams& chainparams, bool& clearWitnessCaches, bool fJustCheck);
+
 /** Replay blocks that aren't fully applied to the database. */
 bool ReplayBlocks(const CChainParams& params, CCoinsView* view);
 

src/wallet/init.cpp

@@ -205,7 +205,7 @@ bool WalletVerify()
     return true;
 }
 
-bool InitLoadWallet()
+bool InitLoadWallet(bool clearWitnessCaches)
 {
     if (gArgs.GetBoolArg("-disablewallet", DEFAULT_DISABLE_WALLET)) {
         LogPrintf("Wallet disabled!\n");
@@ -214,7 +214,7 @@ bool InitLoadWallet()
 
     for (const std::string& walletFile : gArgs.GetArgs("-wallet")) {
         // create/load wallet
-        CWallet * const pwallet = CWallet::CreateWalletFromFile(walletFile, fs::absolute(walletFile, GetWalletDir()));
+        CWallet * const pwallet = CWallet::CreateWalletFromFile(walletFile, fs::absolute(walletFile, GetWalletDir()), clearWitnessCaches);
         if (!pwallet) {
             return false;
         }

src/wallet/init.h

@@ -21,6 +21,6 @@ bool WalletParameterInteraction();
 bool WalletVerify();
 
 //! Load wallet databases.
-bool InitLoadWallet();
+bool InitLoadWallet(bool clearWitnessCaches);
 
 #endif // PIVX_WALLET_INIT_H

src/wallet/wallet.cpp

@@ -4157,14 +4157,14 @@ void CWallet::LockIfMyCollateral(const CTransactionRef& ptx)
     }
 }
 
-CWallet* CWallet::CreateWalletFromFile(const std::string& name, const fs::path& path)
+CWallet* CWallet::CreateWalletFromFile(const std::string& name, const fs::path& path, bool clearWitnessCaches)
 {
     const std::string& walletFile = name;
 
     // needed to restore wallet transaction meta data after -zapwallettxes
     std::vector<CWalletTx> vWtx;
 
-    if (gArgs.GetBoolArg("-zapwallettxes", false)) {
+    if (clearWitnessCaches || gArgs.GetBoolArg("-zapwallettxes", false)) {
         uiInterface.InitMessage(_("Zapping all transactions from wallet..."));
 
         std::unique_ptr<CWallet> tempWallet = std::make_unique<CWallet>(name, WalletDatabase::Create(path));
@@ -4278,7 +4278,7 @@ CWallet* CWallet::CreateWalletFromFile(const std::string& name, const fs::path&
     LOCK(cs_main);
     CBlockIndex* pindexRescan = chainActive.Genesis();
 
-    if (gArgs.GetBoolArg("-rescan", false)) {
+    if (clearWitnessCaches || gArgs.GetBoolArg("-rescan", false)) {
         // clear note witness cache before a full rescan
         walletInstance->ClearNoteWitnessCache();
     } else {
@@ -4326,7 +4326,7 @@ CWallet* CWallet::CreateWalletFromFile(const std::string& name, const fs::path&
         walletInstance->database->IncrementUpdateCounter();
 
         // Restore wallet transaction metadata after -zapwallettxes=1
-        if (gArgs.GetBoolArg("-zapwallettxes", false) && gArgs.GetArg("-zapwallettxes", "1") != "2") {
+        if ((clearWitnessCaches || gArgs.GetBoolArg("-zapwallettxes", false)) && gArgs.GetArg("-zapwallettxes", "1") != "2") {
             WalletBatch batch(*walletInstance->database);
             for (const CWalletTx& wtxOld : vWtx) {
                 uint256 hash = wtxOld.GetHash();

src/wallet/wallet.h

@@ -1189,7 +1189,7 @@ class CWallet : public CCryptoKeyStore, public CValidationInterface
     bool AbandonTransaction(const uint256& hashTx);
 
     /* Initializes the wallet, returns a new CWallet instance or a null pointer in case of an error */
-    static CWallet* CreateWalletFromFile(const std::string& name, const fs::path& path);
+    static CWallet* CreateWalletFromFile(const std::string& name, const fs::path& path, bool clearWitnessCaches);
 
     /**
      * Wallet post-init setup