diff --git a/src/index/base.cpp b/src/index/base.cpp
index dac8deb15..4d15271d2 100644
--- a/src/index/base.cpp
+++ b/src/index/base.cpp
@@ -1,279 +1,280 @@
 // Copyright (c) 2017-2018 The Bitcoin Core developers
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 #include <chain.h>
 #include <chainparams.h>
 #include <config.h>
 #include <index/base.h>
 #include <init.h>
 #include <tinyformat.h>
 #include <ui_interface.h>
 #include <util/system.h>
 #include <validation.h>
 #include <warnings.h>
 
 constexpr char DB_BEST_BLOCK = 'B';
 
 constexpr int64_t SYNC_LOG_INTERVAL = 30;           // seconds
 constexpr int64_t SYNC_LOCATOR_WRITE_INTERVAL = 30; // seconds
 
 template <typename... Args>
 static void FatalError(const char *fmt, const Args &... args) {
     std::string strMessage = tfm::format(fmt, args...);
     SetMiscWarning(strMessage);
     LogPrintf("*** %s\n", strMessage);
     uiInterface.ThreadSafeMessageBox(
         "Error: A fatal internal error occurred, see debug.log for details", "",
         CClientUIInterface::MSG_ERROR);
     StartShutdown();
 }
 
 BaseIndex::DB::DB(const fs::path &path, size_t n_cache_size, bool f_memory,
                   bool f_wipe, bool f_obfuscate)
     : CDBWrapper(path, n_cache_size, f_memory, f_wipe, f_obfuscate) {}
 
 bool BaseIndex::DB::ReadBestBlock(CBlockLocator &locator) const {
     bool success = Read(DB_BEST_BLOCK, locator);
     if (!success) {
         locator.SetNull();
     }
     return success;
 }
 
 bool BaseIndex::DB::WriteBestBlock(const CBlockLocator &locator) {
     return Write(DB_BEST_BLOCK, locator);
 }
 
 BaseIndex::~BaseIndex() {
     Interrupt();
     Stop();
 }
 
 bool BaseIndex::Init() {
     CBlockLocator locator;
     if (!GetDB().ReadBestBlock(locator)) {
         locator.SetNull();
     }
 
     LOCK(cs_main);
     if (locator.IsNull()) {
         m_best_block_index = nullptr;
     } else {
         m_best_block_index = FindForkInGlobalIndex(chainActive, locator);
     }
     m_synced = m_best_block_index.load() == chainActive.Tip();
     return true;
 }
 
-static const CBlockIndex *NextSyncBlock(const CBlockIndex *pindex_prev) {
+static const CBlockIndex *NextSyncBlock(const CBlockIndex *pindex_prev)
+    EXCLUSIVE_LOCKS_REQUIRED(cs_main) {
     AssertLockHeld(cs_main);
 
     if (!pindex_prev) {
         return chainActive.Genesis();
     }
 
     const CBlockIndex *pindex = chainActive.Next(pindex_prev);
     if (pindex) {
         return pindex;
     }
 
     return chainActive.Next(chainActive.FindFork(pindex_prev));
 }
 
 void BaseIndex::ThreadSync() {
     const CBlockIndex *pindex = m_best_block_index.load();
     if (!m_synced) {
         auto &consensus_params = GetConfig().GetChainParams().GetConsensus();
 
         int64_t last_log_time = 0;
         int64_t last_locator_write_time = 0;
         while (true) {
             if (m_interrupt) {
                 WriteBestBlock(pindex);
                 return;
             }
 
             {
                 LOCK(cs_main);
                 const CBlockIndex *pindex_next = NextSyncBlock(pindex);
                 if (!pindex_next) {
                     WriteBestBlock(pindex);
                     m_best_block_index = pindex;
                     m_synced = true;
                     break;
                 }
                 pindex = pindex_next;
             }
 
             int64_t current_time = GetTime();
             if (last_log_time + SYNC_LOG_INTERVAL < current_time) {
                 LogPrintf("Syncing %s with block chain from height %d\n",
                           GetName(), pindex->nHeight);
                 last_log_time = current_time;
             }
 
             if (last_locator_write_time + SYNC_LOCATOR_WRITE_INTERVAL <
                 current_time) {
                 WriteBestBlock(pindex);
                 last_locator_write_time = current_time;
             }
 
             CBlock block;
             if (!ReadBlockFromDisk(block, pindex, consensus_params)) {
                 FatalError("%s: Failed to read block %s from disk", __func__,
                            pindex->GetBlockHash().ToString());
                 return;
             }
             if (!WriteBlock(block, pindex)) {
                 FatalError("%s: Failed to write block %s to index database",
                            __func__, pindex->GetBlockHash().ToString());
                 return;
             }
         }
     }
 
     if (pindex) {
         LogPrintf("%s is enabled at height %d\n", GetName(), pindex->nHeight);
     } else {
         LogPrintf("%s is enabled\n", GetName());
     }
 }
 
 bool BaseIndex::WriteBestBlock(const CBlockIndex *block_index) {
     LOCK(cs_main);
     if (!GetDB().WriteBestBlock(chainActive.GetLocator(block_index))) {
         return error("%s: Failed to write locator to disk", __func__);
     }
     return true;
 }
 
 void BaseIndex::BlockConnected(
     const std::shared_ptr<const CBlock> &block, const CBlockIndex *pindex,
     const std::vector<CTransactionRef> &txn_conflicted) {
     if (!m_synced) {
         return;
     }
 
     const CBlockIndex *best_block_index = m_best_block_index.load();
     if (!best_block_index) {
         if (pindex->nHeight != 0) {
             FatalError("%s: First block connected is not the genesis block "
                        "(height=%d)",
                        __func__, pindex->nHeight);
             return;
         }
     } else {
         // Ensure block connects to an ancestor of the current best block. This
         // should be the case most of the time, but may not be immediately after
         // the the sync thread catches up and sets m_synced. Consider the case
         // where there is a reorg and the blocks on the stale branch are in the
         // ValidationInterface queue backlog even after the sync thread has
         // caught up to the new chain tip. In this unlikely event, log a warning
         // and let the queue clear.
         if (best_block_index->GetAncestor(pindex->nHeight - 1) !=
             pindex->pprev) {
             LogPrintf("%s: WARNING: Block %s does not connect to an ancestor "
                       "of known best chain (tip=%s); not updating index\n",
                       __func__, pindex->GetBlockHash().ToString(),
                       best_block_index->GetBlockHash().ToString());
             return;
         }
     }
 
     if (WriteBlock(*block, pindex)) {
         m_best_block_index = pindex;
     } else {
         FatalError("%s: Failed to write block %s to index", __func__,
                    pindex->GetBlockHash().ToString());
         return;
     }
 }
 
 void BaseIndex::ChainStateFlushed(const CBlockLocator &locator) {
     if (!m_synced) {
         return;
     }
 
     const uint256 &locator_tip_hash = locator.vHave.front();
     const CBlockIndex *locator_tip_index;
     {
         LOCK(cs_main);
         locator_tip_index = LookupBlockIndex(locator_tip_hash);
     }
 
     if (!locator_tip_index) {
         FatalError("%s: First block (hash=%s) in locator was not found",
                    __func__, locator_tip_hash.ToString());
         return;
     }
 
     // This checks that ChainStateFlushed callbacks are received after
     // BlockConnected. The check may fail immediately after the the sync thread
     // catches up and sets m_synced. Consider the case where there is a reorg
     // and the blocks on the stale branch are in the ValidationInterface queue
     // backlog even after the sync thread has caught up to the new chain tip. In
     // this unlikely event, log a warning and let the queue clear.
     const CBlockIndex *best_block_index = m_best_block_index.load();
     if (best_block_index->GetAncestor(locator_tip_index->nHeight) !=
         locator_tip_index) {
         LogPrintf("%s: WARNING: Locator contains block (hash=%s) not on known "
                   "best chain (tip=%s); not writing index locator\n",
                   __func__, locator_tip_hash.ToString(),
                   best_block_index->GetBlockHash().ToString());
         return;
     }
 
     if (!GetDB().WriteBestBlock(locator)) {
         error("%s: Failed to write locator to disk", __func__);
     }
 }
 
 bool BaseIndex::BlockUntilSyncedToCurrentChain() {
     AssertLockNotHeld(cs_main);
 
     if (!m_synced) {
         return false;
     }
 
     {
         // Skip the queue-draining stuff if we know we're caught up with
         // chainActive.Tip().
         LOCK(cs_main);
         const CBlockIndex *chain_tip = chainActive.Tip();
         const CBlockIndex *best_block_index = m_best_block_index.load();
         if (best_block_index->GetAncestor(chain_tip->nHeight) == chain_tip) {
             return true;
         }
     }
 
     LogPrintf("%s: %s is catching up on block notifications\n", __func__,
               GetName());
     SyncWithValidationInterfaceQueue();
     return true;
 }
 
 void BaseIndex::Interrupt() {
     m_interrupt();
 }
 
 void BaseIndex::Start() {
     // Need to register this ValidationInterface before running Init(), so that
     // callbacks are not missed if Init sets m_synced to true.
     RegisterValidationInterface(this);
     if (!Init()) {
         FatalError("%s: %s failed to initialize", __func__, GetName());
         return;
     }
 
     m_thread_sync = std::thread(&TraceThread<std::function<void()>>, GetName(),
                                 std::bind(&BaseIndex::ThreadSync, this));
 }
 
 void BaseIndex::Stop() {
     UnregisterValidationInterface(this);
 
     if (m_thread_sync.joinable()) {
         m_thread_sync.join();
     }
 }
diff --git a/src/validation.h b/src/validation.h
index f8e0f394c..cf7518a23 100644
--- a/src/validation.h
+++ b/src/validation.h
@@ -1,738 +1,739 @@
 // Copyright (c) 2009-2010 Satoshi Nakamoto
 // Copyright (c) 2009-2016 The Bitcoin Core developers
 // Copyright (c) 2017 The Bitcoin developers
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 #ifndef BITCOIN_VALIDATION_H
 #define BITCOIN_VALIDATION_H
 
 #if defined(HAVE_CONFIG_H)
 #include <config/bitcoin-config.h>
 #endif
 
 #include <amount.h>
 #include <blockfileinfo.h>
 #include <coins.h>
 #include <consensus/consensus.h>
 #include <flatfile.h>
 #include <fs.h>
 #include <protocol.h> // For CMessageHeader::MessageMagic
 #include <script/script_error.h>
 #include <sync.h>
 #include <versionbits.h>
 
 #include <algorithm>
 #include <atomic>
 #include <cstdint>
 #include <exception>
 #include <map>
 #include <set>
 #include <string>
 #include <utility>
 #include <vector>
 
 class arith_uint256;
 
 class CBlockIndex;
 class CBlockTreeDB;
 class CChainParams;
 class CChain;
 class CCoinsViewDB;
 class CConnman;
 class CInv;
 class Config;
 class CScriptCheck;
 class CTxMemPool;
 class CTxUndo;
 class CValidationState;
 
 struct FlatFilePos;
 struct ChainTxData;
 struct PrecomputedTransactionData;
 struct LockPoints;
 
 namespace Consensus {
 struct Params;
 }
 
 #define MIN_TRANSACTION_SIZE                                                   \
     (::GetSerializeSize(CTransaction(), SER_NETWORK, PROTOCOL_VERSION))
 
 /** Default for -whitelistrelay. */
 static const bool DEFAULT_WHITELISTRELAY = true;
 /** Default for -whitelistforcerelay. */
 static const bool DEFAULT_WHITELISTFORCERELAY = true;
 /** Default for -minrelaytxfee, minimum relay fee for transactions */
 static const Amount DEFAULT_MIN_RELAY_TX_FEE_PER_KB(1000 * SATOSHI);
 /** Default for -excessutxocharge for transactions transactions */
 static const Amount DEFAULT_UTXO_FEE = Amount::zero();
 //! -maxtxfee default
 static const Amount DEFAULT_TRANSACTION_MAXFEE(COIN / 10);
 //! Discourage users to set fees higher than this amount (in satoshis) per kB
 static const Amount HIGH_TX_FEE_PER_KB(COIN / 100);
 /**
  * -maxtxfee will warn if called with a higher fee than this amount (in satoshis
  */
 static const Amount HIGH_MAX_TX_FEE(100 * HIGH_TX_FEE_PER_KB);
 /** Default for -limitancestorcount, max number of in-mempool ancestors */
 static const unsigned int DEFAULT_ANCESTOR_LIMIT = 25;
 /** Default for -limitancestorsize, maximum kilobytes of tx + all in-mempool
  * ancestors */
 static const unsigned int DEFAULT_ANCESTOR_SIZE_LIMIT = 101;
 /** Default for -limitdescendantcount, max number of in-mempool descendants */
 static const unsigned int DEFAULT_DESCENDANT_LIMIT = 25;
 /** Default for -limitdescendantsize, maximum kilobytes of in-mempool
  * descendants */
 static const unsigned int DEFAULT_DESCENDANT_SIZE_LIMIT = 101;
 /** Default for -mempoolexpiry, expiration time for mempool transactions in
  * hours */
 static const unsigned int DEFAULT_MEMPOOL_EXPIRY = 336;
 /** The maximum size of a blk?????.dat file (since 0.8) */
 static const unsigned int MAX_BLOCKFILE_SIZE = 0x8000000; // 128 MiB
 /** The pre-allocation chunk size for blk?????.dat files (since 0.8) */
 static const unsigned int BLOCKFILE_CHUNK_SIZE = 0x1000000; // 16 MiB
 /** The pre-allocation chunk size for rev?????.dat files (since 0.8) */
 static const unsigned int UNDOFILE_CHUNK_SIZE = 0x100000; // 1 MiB
 
 /** Maximum number of script-checking threads allowed */
 static const int MAX_SCRIPTCHECK_THREADS = 16;
 /** -par default (number of script-checking threads, 0 = auto) */
 static const int DEFAULT_SCRIPTCHECK_THREADS = 0;
 /**
  * Number of blocks that can be requested at any given time from a single peer.
  */
 static const int MAX_BLOCKS_IN_TRANSIT_PER_PEER = 16;
 /**
  * Timeout in seconds during which a peer must stall block download progress
  * before being disconnected.
  */
 static const unsigned int BLOCK_STALLING_TIMEOUT = 2;
 /**
  * Number of headers sent in one getheaders result. We rely on the assumption
  * that if a peer sends less than this number, we reached its tip. Changing this
  * value is a protocol upgrade.
  */
 static const unsigned int MAX_HEADERS_RESULTS = 2000;
 /**
  * Maximum depth of blocks we're willing to serve as compact blocks to peers
  * when requested. For older blocks, a regular BLOCK response will be sent.
  */
 static const int MAX_CMPCTBLOCK_DEPTH = 5;
 /**
  * Maximum depth of blocks we're willing to respond to GETBLOCKTXN requests for.
  */
 static const int MAX_BLOCKTXN_DEPTH = 10;
 /**
  * Size of the "block download window": how far ahead of our current height do
  * we fetch ? Larger windows tolerate larger download speed differences between
  * peer, but increase the potential degree of disordering of blocks on disk
  * (which make reindexing and in the future perhaps pruning harder). We'll
  * probably want to make this a per-peer adaptive value at some point.
  */
 static const unsigned int BLOCK_DOWNLOAD_WINDOW = 1024;
 /** Time to wait (in seconds) between writing blocks/block index to disk. */
 static const unsigned int DATABASE_WRITE_INTERVAL = 60 * 60;
 /** Time to wait (in seconds) between flushing chainstate to disk. */
 static const unsigned int DATABASE_FLUSH_INTERVAL = 24 * 60 * 60;
 /** Maximum length of reject messages. */
 static const unsigned int MAX_REJECT_MESSAGE_LENGTH = 111;
 /** Average delay between local address broadcasts in seconds. */
 static const unsigned int AVG_LOCAL_ADDRESS_BROADCAST_INTERVAL = 24 * 60 * 60;
 /** Average delay between peer address broadcasts in seconds. */
 static const unsigned int AVG_ADDRESS_BROADCAST_INTERVAL = 30;
 /**
  * Average delay between trickled inventory transmissions in seconds.
  * Blocks and whitelisted receivers bypass this, outbound peers get half this
  * delay.
  */
 static const unsigned int INVENTORY_BROADCAST_INTERVAL = 5;
 /**
  * Maximum number of inventory items to send per transmission.
  * Limits the impact of low-fee transaction floods.
  */
 static const unsigned int INVENTORY_BROADCAST_MAX_PER_MB =
     7 * INVENTORY_BROADCAST_INTERVAL;
 /** Average delay between feefilter broadcasts in seconds. */
 static const unsigned int AVG_FEEFILTER_BROADCAST_INTERVAL = 10 * 60;
 /** Maximum feefilter broadcast delay after significant change. */
 static const unsigned int MAX_FEEFILTER_CHANGE_DELAY = 5 * 60;
 /** Block download timeout base, expressed in millionths of the block interval
  * (i.e. 10 min) */
 static const int64_t BLOCK_DOWNLOAD_TIMEOUT_BASE = 1000000;
 /**
  * Additional block download timeout per parallel downloading peer (i.e. 5 min)
  */
 static const int64_t BLOCK_DOWNLOAD_TIMEOUT_PER_PEER = 500000;
 
 static const unsigned int DEFAULT_LIMITFREERELAY = 0;
 static const bool DEFAULT_RELAYPRIORITY = true;
 static const int64_t DEFAULT_MAX_TIP_AGE = 24 * 60 * 60;
 /**
  * Maximum age of our tip in seconds for us to be considered current for fee
  * estimation.
  */
 static const int64_t MAX_FEE_ESTIMATION_TIP_AGE = 3 * 60 * 60;
 
 /** Default for -permitbaremultisig */
 static const bool DEFAULT_PERMIT_BAREMULTISIG = true;
 static const bool DEFAULT_CHECKPOINTS_ENABLED = true;
 static const bool DEFAULT_TXINDEX = false;
 static const unsigned int DEFAULT_BANSCORE_THRESHOLD = 100;
 
 /** Default for -persistmempool */
 static const bool DEFAULT_PERSIST_MEMPOOL = true;
 /** Default for using fee filter */
 static const bool DEFAULT_FEEFILTER = true;
 
 /**
  * Maximum number of headers to announce when relaying blocks with headers
  * message.
  */
 static const unsigned int MAX_BLOCKS_TO_ANNOUNCE = 8;
 
 /** Maximum number of unconnecting headers announcements before DoS score */
 static const int MAX_UNCONNECTING_HEADERS = 10;
 
 static const bool DEFAULT_PEERBLOOMFILTERS = true;
 
 /** Default for -stopatheight */
 static const int DEFAULT_STOPATHEIGHT = 0;
 /** Default for -maxreorgdepth */
 static const int DEFAULT_MAX_REORG_DEPTH = 10;
 /**
  * Default for -finalizationdelay
  * This is the minimum time between a block header reception and the block
  * finalization.
  * This value should be >> block propagation and validation time
  */
 static const int64_t DEFAULT_MIN_FINALIZATION_DELAY = 2 * 60 * 60;
 
 extern CScript COINBASE_FLAGS;
 extern CCriticalSection cs_main;
 extern CTxMemPool g_mempool;
 extern std::atomic_bool g_is_mempool_loaded;
 extern uint64_t nLastBlockTx;
 extern uint64_t nLastBlockSize;
 extern const std::string strMessageMagic;
 extern Mutex g_best_block_mutex;
 extern std::condition_variable g_best_block_cv;
 extern uint256 g_best_block;
 extern std::atomic_bool fImporting;
 extern std::atomic_bool fReindex;
 extern int nScriptCheckThreads;
 extern bool fIsBareMultisigStd;
 extern bool fRequireStandard;
 extern bool fCheckBlockIndex;
 extern bool fCheckpointsEnabled;
 extern size_t nCoinCacheUsage;
 
 /**
  * A fee rate smaller than this is considered zero fee (for relaying, mining and
  * transaction creation)
  */
 extern CFeeRate minRelayTxFee;
 /**
  * Absolute maximum transaction fee (in satoshis) used by wallet and mempool
  * (rejects high fee in sendrawtransaction)
  */
 extern Amount maxTxFee;
 /**
  * If the tip is older than this (in seconds), the node is considered to be in
  * initial block download.
  */
 extern int64_t nMaxTipAge;
 
 /**
  * Block hash whose ancestors we will assume to have valid scripts without
  * checking them.
  */
 extern uint256 hashAssumeValid;
 
 /**
  * Minimum work we will assume exists on some valid chain.
  */
 extern arith_uint256 nMinimumChainWork;
 
 /**
  * Best header we've seen so far (used for getheaders queries' starting points).
  */
 extern CBlockIndex *pindexBestHeader;
 
 /** Pruning-related variables and constants */
 /** True if any block files have ever been pruned. */
 extern bool fHavePruned;
 /** True if we're running in -prune mode. */
 extern bool fPruneMode;
 /** Number of MiB of block files that we're trying to stay below. */
 extern uint64_t nPruneTarget;
 /** Block files containing a block-height within MIN_BLOCKS_TO_KEEP of
  * chainActive.Tip() will not be pruned. */
 static const unsigned int MIN_BLOCKS_TO_KEEP = 288;
 /** Minimum blocks required to signal NODE_NETWORK_LIMITED */
 static const unsigned int NODE_NETWORK_LIMITED_MIN_BLOCKS = 288;
 
 static const signed int DEFAULT_CHECKBLOCKS = 6;
 static const unsigned int DEFAULT_CHECKLEVEL = 3;
 
 /**
  * Require that user allocate at least 550MB for block & undo files (blk???.dat
  * and rev???.dat)
  * At 1MB per block, 288 blocks = 288MB.
  * Add 15% for Undo data = 331MB
  * Add 20% for Orphan block rate = 397MB
  * We want the low water mark after pruning to be at least 397 MB and since we
  * prune in full block file chunks, we need the high water mark which triggers
  * the prune to be one 128MB block file + added 15% undo data = 147MB greater
  * for a total of 545MB. Setting the target to > than 550MB will make it likely
  * we can respect the target.
  */
 static const uint64_t MIN_DISK_SPACE_FOR_BLOCK_FILES = 550 * 1024 * 1024;
 
 class BlockValidationOptions {
 private:
     uint64_t excessiveBlockSize;
     bool checkPoW : 1;
     bool checkMerkleRoot : 1;
 
 public:
     // Do full validation by default
     BlockValidationOptions(const Config &config);
     BlockValidationOptions(uint64_t _excessiveBlockSize, bool _checkPow = true,
                            bool _checkMerkleRoot = true)
         : excessiveBlockSize(_excessiveBlockSize), checkPoW(_checkPow),
           checkMerkleRoot(_checkMerkleRoot) {}
 
     BlockValidationOptions withCheckPoW(bool _checkPoW = true) const {
         BlockValidationOptions ret = *this;
         ret.checkPoW = _checkPoW;
         return ret;
     }
 
     BlockValidationOptions
     withCheckMerkleRoot(bool _checkMerkleRoot = true) const {
         BlockValidationOptions ret = *this;
         ret.checkMerkleRoot = _checkMerkleRoot;
         return ret;
     }
 
     bool shouldValidatePoW() const { return checkPoW; }
     bool shouldValidateMerkleRoot() const { return checkMerkleRoot; }
     uint64_t getExcessiveBlockSize() const { return excessiveBlockSize; }
 };
 
 /**
  * Process an incoming block. This only returns after the best known valid
  * block is made active. Note that it does not, however, guarantee that the
  * specific block passed to it has been checked for validity!
  *
  * If you want to *possibly* get feedback on whether pblock is valid, you must
  * install a CValidationInterface (see validationinterface.h) - this will have
  * its BlockChecked method called whenever *any* block completes validation.
  *
  * Note that we guarantee that either the proof-of-work is valid on pblock, or
  * (and possibly also) BlockChecked will have been called.
  *
  * May not be called with cs_main held. May not be called in a
  * validationinterface callback.
  *
  * @param[in]   config  The global config.
  * @param[in]   pblock  The block we want to process.
  * @param[in]   fForceProcessing Process this block even if unrequested; used
  * for non-network block sources and whitelisted peers.
  * @param[out]  fNewBlock A boolean which is set to indicate if the block was
  *                        first received via this call.
  * @return True if the block is accepted as a valid block.
  */
 bool ProcessNewBlock(const Config &config,
                      const std::shared_ptr<const CBlock> pblock,
                      bool fForceProcessing, bool *fNewBlock);
 
 /**
  * Process incoming block headers.
  *
  * May not be called with cs_main held. May not be called in a
  * validationinterface callback.
  *
  * @param[in]  config        The config.
  * @param[in]  block         The block headers themselves.
  * @param[out] state         This may be set to an Error state if any error
  *                           occurred processing them.
  * @param[out] ppindex       If set, the pointer will be set to point to the
  *                           last new block index object for the given headers.
  * @param[out] first_invalid First header that fails validation, if one exists.
  * @return True if block headers were accepted as valid.
  */
 bool ProcessNewBlockHeaders(const Config &config,
                             const std::vector<CBlockHeader> &block,
                             CValidationState &state,
                             const CBlockIndex **ppindex = nullptr,
                             CBlockHeader *first_invalid = nullptr);
 
 /**
  * Open a block file (blk?????.dat).
  */
 FILE *OpenBlockFile(const FlatFilePos &pos, bool fReadOnly = false);
 
 /**
  * Translation to a filesystem path.
  */
 fs::path GetBlockPosFilename(const FlatFilePos &pos);
 
 /**
  * Import blocks from an external file.
  */
 bool LoadExternalBlockFile(const Config &config, FILE *fileIn,
                            FlatFilePos *dbp = nullptr);
 
 /**
  * Ensures we have a genesis block in the block tree, possibly writing one to
  * disk.
  */
 bool LoadGenesisBlock(const CChainParams &chainparams);
 
 /**
  * Load the block tree and coins database from disk, initializing state if we're
  * running with -reindex.
  */
 bool LoadBlockIndex(const Config &config);
 
 /**
  * Update the chain tip based on database information.
  */
-bool LoadChainTip(const Config &config);
+bool LoadChainTip(const Config &config) EXCLUSIVE_LOCKS_REQUIRED(cs_main);
 
 /**
  * Unload database information.
  */
 void UnloadBlockIndex();
 
 /**
  * Run an instance of the script checking thread.
  */
 void ThreadScriptCheck();
 
 /**
  * Check whether we are doing an initial block download (synchronizing from disk
  * or network)
  */
 bool IsInitialBlockDownload();
 
 /**
  * Retrieve a transaction (from memory pool, or from disk, if possible).
  */
 bool GetTransaction(const Consensus::Params &params, const TxId &txid,
                     CTransactionRef &tx, uint256 &hashBlock,
                     bool fAllowSlow = false, CBlockIndex *blockIndex = nullptr);
 
 /**
  * Find the best known block, and make it the tip of the block chain
  *
  * May not be called with cs_main held. May not be called in a
  * validationinterface callback.
  */
 bool ActivateBestChain(
     const Config &config, CValidationState &state,
     std::shared_ptr<const CBlock> pblock = std::shared_ptr<const CBlock>());
 Amount GetBlockSubsidy(int nHeight, const Consensus::Params &consensusParams);
 
 /**
  * Guess verification progress (as a fraction between 0.0=genesis and
  * 1.0=current tip).
  */
 double GuessVerificationProgress(const ChainTxData &data,
                                  const CBlockIndex *pindex);
 
 /**
  * Calculate the amount of disk space the block & undo files currently use.
  */
 uint64_t CalculateCurrentUsage();
 
 /**
  * Mark one block file as pruned.
  */
 void PruneOneBlockFile(const int fileNumber);
 
 /**
  * Actually unlink the specified files
  */
 void UnlinkPrunedFiles(const std::set<int> &setFilesToPrune);
 
 /** Flush all state, indexes and buffers to disk. */
 void FlushStateToDisk();
 /** Prune block files and flush state to disk. */
 void PruneAndFlush();
 /** Prune block files up to a given height */
 void PruneBlockFilesManual(int nManualPruneHeight);
 
 /**
  * (try to) add transaction to memory pool
  */
 bool AcceptToMemoryPool(const Config &config, CTxMemPool &pool,
                         CValidationState &state, const CTransactionRef &tx,
                         bool fLimitFree, bool *pfMissingInputs,
                         bool fOverrideMempoolLimit = false,
                         const Amount nAbsurdFee = Amount::zero(),
                         bool test_accept = false)
     EXCLUSIVE_LOCKS_REQUIRED(cs_main);
 
 /** Convert CValidationState to a human-readable message for logging */
 std::string FormatStateMessage(const CValidationState &state);
 
 /**
  * Check whether all inputs of this transaction are valid (no double spends,
  * scripts & sigs, amounts). This does not modify the UTXO set.
  *
  * If pvChecks is not nullptr, script checks are pushed onto it instead of being
  * performed inline. Any script checks which are not necessary (eg due to script
  * execution cache hits) are, obviously, not pushed onto pvChecks/run.
  *
  * Setting sigCacheStore/scriptCacheStore to false will remove elements from the
  * corresponding cache which are matched. This is useful for checking blocks
  * where we will likely never need the cache entry again.
  */
 bool CheckInputs(const CTransaction &tx, CValidationState &state,
                  const CCoinsViewCache &view, bool fScriptChecks,
                  const uint32_t flags, bool sigCacheStore,
                  bool scriptCacheStore,
                  const PrecomputedTransactionData &txdata,
                  std::vector<CScriptCheck> *pvChecks = nullptr);
 
 /**
  * Mark all the coins corresponding to a given transaction inputs as spent.
  */
 void SpendCoins(CCoinsViewCache &view, const CTransaction &tx, CTxUndo &txundo,
                 int nHeight);
 
 /**
  * Apply the effects of this transaction on the UTXO set represented by view.
  */
 void UpdateCoins(CCoinsViewCache &view, const CTransaction &tx, int nHeight);
 void UpdateCoins(CCoinsViewCache &view, const CTransaction &tx, CTxUndo &txundo,
                  int nHeight);
 
 /**
  * Test whether the LockPoints height and time are still valid on the current
  * chain.
  */
 bool TestLockPointValidity(const LockPoints *lp)
     EXCLUSIVE_LOCKS_REQUIRED(cs_main);
 
 /**
  * Check if transaction will be BIP 68 final in the next block to be created.
  *
  * Simulates calling SequenceLocks() with data from the tip of the current
  * active chain. Optionally stores in LockPoints the resulting height and time
  * calculated and the hash of the block needed for calculation or skips the
  * calculation and uses the LockPoints passed in for evaluation. The LockPoints
  * should not be considered valid if CheckSequenceLocks returns false.
  *
  * See consensus/consensus.h for flag definitions.
  */
 bool CheckSequenceLocks(const CTxMemPool &pool, const CTransaction &tx,
                         int flags, LockPoints *lp = nullptr,
                         bool useExistingLockPoints = false)
     EXCLUSIVE_LOCKS_REQUIRED(cs_main);
 
 /**
  * Closure representing one script verification.
  * Note that this stores references to the spending transaction.
  */
 class CScriptCheck {
 private:
     CScript scriptPubKey;
     Amount amount;
     const CTransaction *ptxTo;
     unsigned int nIn;
     uint32_t nFlags;
     bool cacheStore;
     ScriptError error;
     PrecomputedTransactionData txdata;
 
 public:
     CScriptCheck()
         : amount(), ptxTo(nullptr), nIn(0), nFlags(0), cacheStore(false),
           error(ScriptError::UNKNOWN), txdata() {}
 
     CScriptCheck(const CScript &scriptPubKeyIn, const Amount amountIn,
                  const CTransaction &txToIn, unsigned int nInIn,
                  uint32_t nFlagsIn, bool cacheIn,
                  const PrecomputedTransactionData &txdataIn)
         : scriptPubKey(scriptPubKeyIn), amount(amountIn), ptxTo(&txToIn),
           nIn(nInIn), nFlags(nFlagsIn), cacheStore(cacheIn),
           error(ScriptError::UNKNOWN), txdata(txdataIn) {}
 
     bool operator()();
 
     void swap(CScriptCheck &check) {
         scriptPubKey.swap(check.scriptPubKey);
         std::swap(ptxTo, check.ptxTo);
         std::swap(amount, check.amount);
         std::swap(nIn, check.nIn);
         std::swap(nFlags, check.nFlags);
         std::swap(cacheStore, check.cacheStore);
         std::swap(error, check.error);
         std::swap(txdata, check.txdata);
     }
 
     ScriptError GetScriptError() const { return error; }
 };
 
 /** Functions for disk access for blocks */
 bool ReadBlockFromDisk(CBlock &block, const FlatFilePos &pos,
                        const Consensus::Params &params);
 bool ReadBlockFromDisk(CBlock &block, const CBlockIndex *pindex,
                        const Consensus::Params &params);
 
 /** Functions for validating blocks and updating the block tree */
 
 /**
  * Context-independent validity checks.
  *
  * Returns true if the provided block is valid (has valid header,
  * transactions are valid, block is a valid size, etc.)
  */
 bool CheckBlock(const CBlock &block, CValidationState &state,
                 const Consensus::Params &params,
                 BlockValidationOptions validationOptions);
 
 /**
  * This is a variant of ContextualCheckTransaction which computes the contextual
  * check for a transaction based on the chain tip.
  *
  * See consensus/consensus.h for flag definitions.
  */
 bool ContextualCheckTransactionForCurrentBlock(const Consensus::Params &params,
                                                const CTransaction &tx,
                                                CValidationState &state,
                                                int flags = -1);
 
 /**
  * Check a block is completely valid from start to finish (only works on top of
  * our current best block, with cs_main held)
  */
 bool TestBlockValidity(CValidationState &state, const CChainParams &params,
                        const CBlock &block, CBlockIndex *pindexPrev,
                        BlockValidationOptions validationOptions);
 
 /**
  * When there are blocks in the active chain with missing data, rewind the
  * chainstate and remove them from the block index.
  */
 bool RewindBlockIndex(const Config &config);
 
 /**
  * RAII wrapper for VerifyDB: Verify consistency of the block and coin
  * databases.
  */
 class CVerifyDB {
 public:
     CVerifyDB();
     ~CVerifyDB();
     bool VerifyDB(const Config &config, CCoinsView *coinsview, int nCheckLevel,
                   int nCheckDepth);
 };
 
 /** Replay blocks that aren't fully applied to the database. */
 bool ReplayBlocks(const Consensus::Params &params, CCoinsView *view);
 
 /** Find the last common block between the parameter chain and a locator. */
 CBlockIndex *FindForkInGlobalIndex(const CChain &chain,
-                                   const CBlockLocator &locator);
+                                   const CBlockLocator &locator)
+    EXCLUSIVE_LOCKS_REQUIRED(cs_main);
 
 /**
  * Mark a block as precious and reorganize.
  *
  * May not be called with cs_main held. May not be called in a
  * validationinterface callback.
  */
 bool PreciousBlock(const Config &config, CValidationState &state,
                    CBlockIndex *pindex);
 
 /**
  * Mark a block as finalized.
  * A finalized block can not be reorged in any way.
  */
 bool FinalizeBlockAndInvalidate(const Config &config, CValidationState &state,
                                 CBlockIndex *pindex);
 
 /** Mark a block as invalid. */
 bool InvalidateBlock(const Config &config, CValidationState &state,
                      CBlockIndex *pindex);
 
 /** Park a block. */
 bool ParkBlock(const Config &config, CValidationState &state,
                CBlockIndex *pindex);
 
 /** Remove invalidity status from a block and its descendants. */
 void ResetBlockFailureFlags(CBlockIndex *pindex);
 
 /** Remove parked status from a block and its descendants. */
 void UnparkBlockAndChildren(CBlockIndex *pindex);
 
 /** Remove parked status from a block. */
 void UnparkBlock(CBlockIndex *pindex);
 
 /**
  * Retrieve the topmost finalized block.
  */
 const CBlockIndex *GetFinalizedBlock();
 
 /**
  * Checks if a block is finalized.
  */
 bool IsBlockFinalized(const CBlockIndex *pindex);
 
 /** The currently-connected chain of blocks (protected by cs_main). */
 extern CChain &chainActive;
 
 /**
  * Global variable that points to the coins database (protected by cs_main)
  */
 extern std::unique_ptr<CCoinsViewDB> pcoinsdbview;
 
 /**
  * Global variable that points to the active CCoinsView (protected by cs_main)
  */
 extern std::unique_ptr<CCoinsViewCache> pcoinsTip;
 
 /**
  * Global variable that points to the active block tree (protected by cs_main)
  */
 extern std::unique_ptr<CBlockTreeDB> pblocktree;
 
 /**
  * Return the spend height, which is one more than the inputs.GetBestBlock().
  * While checking, GetBestBlock() refers to the parent block. (protected by
  * cs_main)
  * This is also true for mempool checks.
  */
 int GetSpendHeight(const CCoinsViewCache &inputs);
 
 /**
  * Determine what nVersion a new block should use.
  */
 int32_t ComputeBlockVersion(const CBlockIndex *pindexPrev,
                             const Consensus::Params &params);
 
 /**
  * Reject codes greater or equal to this can be returned by AcceptToMemPool or
  * AcceptBlock for blocks/transactions, to signal internal conditions. They
  * cannot and should not be sent over the P2P network.
  */
 static const unsigned int REJECT_INTERNAL = 0x100;
 /** Too high fee. Can not be triggered by P2P transactions */
 static const unsigned int REJECT_HIGHFEE = 0x100;
 /** Block conflicts with a transaction already known */
 static const unsigned int REJECT_AGAINST_FINALIZED = 0x103;
 
 /** Get block file info entry for one block file */
 CBlockFileInfo *GetBlockFileInfo(size_t n);
 
 /** Dump the mempool to disk. */
 bool DumpMempool();
 
 /** Load the mempool from disk. */
 bool LoadMempool(const Config &config);
 
 #endif // BITCOIN_VALIDATION_H