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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* Bitcoin Core P2P design
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return;
            }
        }
        
        
        
        
        bool fProcessBLOCKTXN = false;
        CDataStream blockTxnMsg(SER_NETWORK, PROTOCOL_VERSION);
        
        
        bool fRevertToHeaderProcessing = false;
        
        
        std::shared_ptr<CBlock> pblock = std::make_shared<CBlock>();
        bool fBlockReconstructed = false;
        {
        LOCK2(cs_main, g_cs_orphans);
        
        assert(pindex);
        UpdateBlockAvailability(pfrom.GetId(), pindex->GetBlockHash());
        CNodeState *nodestate = State(pfrom.GetId());
        
        
        if (received_new_header && pindex->nChainWork > m_chainman.ActiveChain().Tip()->nChainWork) {
            nodestate->m_last_block_announcement = GetTime();
        }
        std::map<uint256, std::pair<NodeId, std::list<QueuedBlock>::iterator> >::iterator blockInFlightIt = mapBlocksInFlight.find(pindex->GetBlockHash());
        bool fAlreadyInFlight = blockInFlightIt != mapBlocksInFlight.end();
        if (pindex->nStatus & BLOCK_HAVE_DATA)