There are some potential feefilter cleanups mentioned and motivated in comment https://github.com/bitcoin/bitcoin/pull/21509#issuecomment-805808485 . If you address the locking one, please be careful and make sure that `round()` is only called under a lock. See https://github.com/bitcoin/bitcoin/pull/21509#issuecomment-807992199

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bool ConnectBlock(const CBlock& block, BlockValidationState& state, CBlockIndex* pindex,
                      CCoinsViewCache& view, const CChainParams& chainparams, bool fJustCheck = false) EXCLUSIVE_LOCKS_REQUIRED(cs_main);
    
    bool DisconnectTip(BlockValidationState& state, const CChainParams& chainparams, DisconnectedBlockTransactions* disconnectpool) EXCLUSIVE_LOCKS_REQUIRED(cs_main, m_mempool.cs);
    
    /** Mark a block as precious and reorganize.
     *
     * May not be called in a validationinterface callback.
     */
    bool PreciousBlock(BlockValidationState& state, const CChainParams& params, CBlockIndex* pindex) LOCKS_EXCLUDED(cs_main);
    
    bool InvalidateBlock(BlockValidationState& state, const CChainParams& chainparams, CBlockIndex* pindex) LOCKS_EXCLUDED(cs_main);
    
    void ResetBlockFailureFlags(CBlockIndex* pindex) EXCLUSIVE_LOCKS_REQUIRED(cs_main);
    
    bool ReplayBlocks(const CChainParams& params);
    
    [[nodiscard]] bool NeedsRedownload(const CChainParams& params) const EXCLUSIVE_LOCKS_REQUIRED(cs_main);
    
    bool LoadGenesisBlock(const CChainParams& chainparams);
    void PruneBlockIndexCandidates();
    void UnloadBlockIndex();
    
    bool IsInitialBlockDownload() const;
    /**
     * Make various assertions about the state of the block index.
     *
     * By default this only executes fully when using the Regtest chain; see: fCheckBlockIndex.
     */
    void CheckBlockIndex(const Consensus::Params& consensusParams);