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feat: enhance CQuorumManager with active chain view and ancestor caching #6962

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3db85e2
feat: enhance CQuorumManager with active chain view and ancestor caching
PastaPastaPasta Nov 11, 2025
bd8c92e
fix: correct ancestor computation in quorum scanning and selection
PastaPastaPasta Nov 12, 2025
a8fb74f
fix: prevent stale cached tip in ScanQuorums(size_t) by preferring ac…
PastaPastaPasta Nov 12, 2025
970ba10
fix: resolve quorum selection against active chain when signHeight is…
PastaPastaPasta Nov 12, 2025
56f40c3
fix: make SelectQuorumForSigning resolve strictly via active chain un…
PastaPastaPasta Nov 12, 2025
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143 changes: 129 additions & 14 deletions src/llmq/quorums.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -25,7 +25,9 @@
#include <util/time.h>
#include <util/underlying.h>
#include <validation.h>
#include <validationinterface.h>

#include <algorithm>
#include <cxxtimer.hpp>

namespace llmq
Expand Down Expand Up @@ -207,6 +209,82 @@ bool CQuorum::ReadContributions(const CDBWrapper& db)
return true;
}

size_t CQuorumManager::ComputeAncestorCacheMaxSize()
{
size_t max_size = 0;
for (const auto& llmq : Params().GetConsensus().llmqs) {
size_t size = llmq.max_cycles(llmq.keepOldConnections) * (llmq.dkgMiningWindowEnd - llmq.dkgMiningWindowStart) + 128;
max_size = std::max(max_size, size);
}
// Clamp to reasonable bounds
return std::clamp(max_size, size_t(512), size_t(4096));
}

CQuorumManager::ActiveChainView CQuorumManager::GetActiveChainView() const
{
LOCK(cs_active_chain_view);
return m_active_chain_view;
}

const CBlockIndex* CQuorumManager::FindAncestorFast(const ActiveChainView& view, int target_height) const
{
if (target_height < 0 || target_height > view.height || !view.tip) {
return nullptr;
}
LOCK(cs_ancestor_cache);
if (m_lru_tip_hash != view.hash) {
// Distinguish extension vs reorg (or skipped updates).
// If the previous tip hash is an ancestor of the current tip at the recorded height,
// this is an extension (possibly by multiple blocks) and the cache remains valid.
// Otherwise, clear the cache to avoid cross-fork pollution.
bool is_extension = false;
if (m_lru_tip_height >= 0) {
const CBlockIndex* old_tip_as_ancestor = view.tip->GetAncestor(m_lru_tip_height);
if (old_tip_as_ancestor && old_tip_as_ancestor->GetBlockHash() == m_lru_tip_hash) {
is_extension = true;
}
}
if (!is_extension) {
m_ancestor_lru.clear();
}
m_lru_tip_hash = view.hash;
m_lru_tip_height = view.height;
}
const CBlockIndex* out;
if (m_ancestor_lru.get(target_height, out)) {
return out;
}
out = view.tip->GetAncestor(target_height);
if (out) {
m_ancestor_lru.insert(target_height, out);
}
return out;
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⚠️ Potential issue | 🔴 Critical

Fix clang-format issue.

The CI pipeline reports a clang-format difference at this line. Please run clang-format to fix the formatting.

🧰 Tools
🪛 GitHub Actions: Clang Diff Format Check

[error] 261-261: Clang-format differences found in quorums.cpp. Apply clang-format to fix formatting differences.

🤖 Prompt for AI Agents 
In src/llmq/quorums.cpp around line 261, the file's formatting at the return
statement does not match clang-format expectations; run clang-format (using the
repo's configured style) on this file or adjust whitespace so the line reads
exactly as formatted by clang-format (e.g., ensure correct indentation and
spacing around the return statement) and commit the resulting change.

}

void CQuorumManager::ChainViewSubscriber::UpdatedBlockTip(const CBlockIndex* pindexNew, const CBlockIndex* pindexFork, bool fInitialDownload)
{
if (!pindexNew) return;

// Update snapshot
{
LOCK(m_qman.cs_active_chain_view);
m_qman.m_active_chain_view.tip = pindexNew;
m_qman.m_active_chain_view.height = pindexNew->nHeight;
m_qman.m_active_chain_view.hash = pindexNew->GetBlockHash();
}

// Handle ancestor cache: clear on reorg, keep on extension
{
LOCK(m_qman.cs_ancestor_cache);
if (pindexFork != pindexNew->pprev) {
// Reorg detected: clear cache
m_qman.m_ancestor_lru.clear();
}
m_qman.m_lru_tip_hash = pindexNew->GetBlockHash();
m_qman.m_lru_tip_height = pindexNew->nHeight;
}
}

CQuorumManager::CQuorumManager(CBLSWorker& _blsWorker, CChainState& chainstate, CDeterministicMNManager& dmnman,
CDKGSessionManager& _dkgManager, CEvoDB& _evoDb,
CQuorumBlockProcessor& _quorumBlockProcessor, CQuorumSnapshotManager& qsnapman,
Expand All @@ -222,16 +300,36 @@ CQuorumManager::CQuorumManager(CBLSWorker& _blsWorker, CChainState& chainstate,
m_qsnapman{qsnapman},
m_mn_activeman{mn_activeman},
m_mn_sync{mn_sync},
m_sporkman{sporkman}
m_sporkman{sporkman},
m_ancestor_lru{ComputeAncestorCacheMaxSize()}
{
utils::InitQuorumsCache(mapQuorumsCache, false);
quorumThreadInterrupt.reset();
MigrateOldQuorumDB(_evoDb);

// Initialize snapshot from current tip (under cs_main for bootstrap)
{
LOCK(::cs_main);
const CBlockIndex* tip = m_chainstate.m_chain.Tip();
if (tip) {
LOCK(cs_active_chain_view);
m_active_chain_view.tip = tip;
m_active_chain_view.height = tip->nHeight;
m_active_chain_view.hash = tip->GetBlockHash();
}
}

// Register ValidationInterface subscriber
m_chain_view_subscriber = std::make_unique<ChainViewSubscriber>(*this);
RegisterValidationInterface(m_chain_view_subscriber.get());
}

CQuorumManager::~CQuorumManager()
{
Stop();
if (m_chain_view_subscriber) {
UnregisterValidationInterface(m_chain_view_subscriber.get());
}
}

void CQuorumManager::Start()
Expand Down Expand Up @@ -523,7 +621,17 @@ bool CQuorumManager::RequestQuorumData(CNode* pfrom, CConnman& connman, const CQ

std::vector<CQuorumCPtr> CQuorumManager::ScanQuorums(Consensus::LLMQType llmqType, size_t nCountRequested) const
{
const CBlockIndex* pindex = WITH_LOCK(::cs_main, return m_chainstate.m_chain.Tip());
auto view = GetActiveChainView();
const CBlockIndex* pindex = view.tip;
if (pindex == nullptr) {
pindex = WITH_LOCK(::cs_main, return m_chainstate.m_chain.Tip());
} else {
// If the cached view lags behind the active chain, prefer the up-to-date tip for correctness.
const int active_height = WITH_LOCK(::cs_main, return m_chainstate.m_chain.Height());
if (view.height < active_height) {
pindex = WITH_LOCK(::cs_main, return m_chainstate.m_chain.Tip());
}
}
return ScanQuorums(llmqType, pindex, nCountRequested);
}

Expand All @@ -547,10 +655,17 @@ std::vector<CQuorumCPtr> CQuorumManager::ScanQuorums(Consensus::LLMQType llmqTyp
// too early for this cycle, use the previous one
// bail out if it's below genesis block
if (quorumCycleMiningEndHeight < llmq_params_opt->dkgInterval) return {};
pindexStore = pindexStart->GetAncestor(quorumCycleMiningEndHeight - llmq_params_opt->dkgInterval);
// IMPORTANT: compute ancestors strictly relative to pindexStart's chain context
// to avoid cross-fork/cross-tip contamination from global cached views.
const CBlockIndex* ancestor = pindexStart->GetAncestor(quorumCycleMiningEndHeight - llmq_params_opt->dkgInterval);
if (ancestor == nullptr) return {};
pindexStore = gsl::not_null<const CBlockIndex*>{ancestor};
} else if (pindexStart->nHeight > quorumCycleMiningEndHeight) {
// we are past the mining phase of this cycle, use it
pindexStore = pindexStart->GetAncestor(quorumCycleMiningEndHeight);
// See note above: stay on pindexStart's chain
const CBlockIndex* ancestor = pindexStart->GetAncestor(quorumCycleMiningEndHeight);
if (ancestor == nullptr) return {};
pindexStore = gsl::not_null<const CBlockIndex*>{ancestor};
}
// everything else is inside the mining phase of this cycle, no pindexStore adjustment needed

Expand Down Expand Up @@ -1210,17 +1325,17 @@ CQuorumCPtr SelectQuorumForSigning(const Consensus::LLMQParams& llmq_params, con
size_t poolSize = llmq_params.signingActiveQuorumCount;

CBlockIndex* pindexStart;
{
LOCK(::cs_main);
if (signHeight == -1) {
signHeight = active_chain.Height();
}
int startBlockHeight = signHeight - signOffset;
if (startBlockHeight > active_chain.Height() || startBlockHeight < 0) {
return {};
}
pindexStart = active_chain[startBlockHeight];
// Resolve strictly relative to the authoritative active chain to avoid any
// cross-tip inconsistencies during rotations or rapid tip changes.
LOCK(::cs_main);
if (signHeight == -1) {
signHeight = active_chain.Height();
}
int startBlockHeight = signHeight - signOffset;
if (startBlockHeight > active_chain.Height() || startBlockHeight < 0) {
return {};
}
pindexStart = active_chain[startBlockHeight];

if (IsQuorumRotationEnabled(llmq_params, pindexStart)) {
auto quorums = qman.ScanQuorums(llmq_params.type, pindexStart, poolSize);
Expand Down
43 changes: 38 additions & 5 deletions src/llmq/quorums.h
View file
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Original file line number Diff line number Diff line change
Expand Up @@ -17,10 +17,12 @@
#include <saltedhasher.h>
#include <util/threadinterrupt.h>
#include <util/time.h>
#include <validationinterface.h>

#include <gsl/pointers.h>

#include <atomic>
#include <functional>
#include <map>
#include <utility>

Expand Down Expand Up @@ -258,6 +260,33 @@ class CQuorumManager
// it maps `quorum_hash` to `pindex`
mutable Uint256LruHashMap<const CBlockIndex*, 128 /*max_size*/> quorumBaseBlockIndexCache;

// Active chain snapshot to avoid cs_main contention
struct ActiveChainView {
const CBlockIndex* tip{nullptr};
int height{-1};
uint256 hash;
};
mutable Mutex cs_active_chain_view;
ActiveChainView m_active_chain_view GUARDED_BY(cs_active_chain_view);

// Ancestor lookup cache (height -> CBlockIndex*) for current tip
mutable Mutex cs_ancestor_cache;
mutable unordered_lru_cache<int, const CBlockIndex*, std::hash<int>> m_ancestor_lru GUARDED_BY(cs_ancestor_cache);
mutable uint256 m_lru_tip_hash GUARDED_BY(cs_ancestor_cache);
mutable int m_lru_tip_height GUARDED_BY(cs_ancestor_cache){-1};
static size_t ComputeAncestorCacheMaxSize();

// ValidationInterface subscriber for tip updates
class ChainViewSubscriber : public CValidationInterface {
public:
explicit ChainViewSubscriber(CQuorumManager& qman) : m_qman(qman) {}
virtual ~ChainViewSubscriber() = default;
void UpdatedBlockTip(const CBlockIndex* pindexNew, const CBlockIndex* pindexFork, bool fInitialDownload) override;
private:
CQuorumManager& m_qman;
};
std::unique_ptr<ChainViewSubscriber> m_chain_view_subscriber;

mutable ctpl::thread_pool workerPool;
mutable CThreadInterrupt quorumThreadInterrupt;

Expand All @@ -276,10 +305,10 @@ class CQuorumManager
void Stop();

void TriggerQuorumDataRecoveryThreads(CConnman& connman, const CBlockIndex* pIndex) const
EXCLUSIVE_LOCKS_REQUIRED(!cs_db, !cs_scan_quorums, !cs_map_quorums);
EXCLUSIVE_LOCKS_REQUIRED(!cs_db, !cs_scan_quorums, !cs_map_quorums, !cs_active_chain_view, !cs_ancestor_cache);

void UpdatedBlockTip(const CBlockIndex* pindexNew, CConnman& connman, bool fInitialDownload) const
EXCLUSIVE_LOCKS_REQUIRED(!cs_db, !cs_scan_quorums, !cs_map_quorums);
EXCLUSIVE_LOCKS_REQUIRED(!cs_db, !cs_scan_quorums, !cs_map_quorums, !cs_active_chain_view, !cs_ancestor_cache);

[[nodiscard]] MessageProcessingResult ProcessMessage(CNode& pfrom, CConnman& connman, std::string_view msg_type,
CDataStream& vRecv)
Expand All @@ -294,17 +323,21 @@ class CQuorumManager
CQuorumCPtr GetQuorum(Consensus::LLMQType llmqType, const uint256& quorumHash) const
EXCLUSIVE_LOCKS_REQUIRED(!cs_db, !cs_map_quorums);
std::vector<CQuorumCPtr> ScanQuorums(Consensus::LLMQType llmqType, size_t nCountRequested) const
EXCLUSIVE_LOCKS_REQUIRED(!cs_db, !cs_map_quorums, !cs_scan_quorums);
EXCLUSIVE_LOCKS_REQUIRED(!cs_db, !cs_map_quorums, !cs_scan_quorums, !cs_active_chain_view, !cs_ancestor_cache);

// this one is cs_main-free
std::vector<CQuorumCPtr> ScanQuorums(Consensus::LLMQType llmqType, const CBlockIndex* pindexStart,
size_t nCountRequested) const
EXCLUSIVE_LOCKS_REQUIRED(!cs_db, !cs_map_quorums, !cs_scan_quorums);
EXCLUSIVE_LOCKS_REQUIRED(!cs_db, !cs_map_quorums, !cs_scan_quorums, !cs_active_chain_view, !cs_ancestor_cache);

// Active chain snapshot accessors (public for use by SelectQuorumForSigning)
ActiveChainView GetActiveChainView() const EXCLUSIVE_LOCKS_REQUIRED(!cs_active_chain_view);
const CBlockIndex* FindAncestorFast(const ActiveChainView& view, int target_height) const EXCLUSIVE_LOCKS_REQUIRED(!cs_ancestor_cache);

private:
// all private methods here are cs_main-free
void CheckQuorumConnections(CConnman& connman, const Consensus::LLMQParams& llmqParams, const CBlockIndex* pindexNew) const
EXCLUSIVE_LOCKS_REQUIRED(!cs_db, !cs_scan_quorums, !cs_map_quorums);
EXCLUSIVE_LOCKS_REQUIRED(!cs_db, !cs_scan_quorums, !cs_map_quorums, !cs_active_chain_view, !cs_ancestor_cache);

CQuorumPtr BuildQuorumFromCommitment(Consensus::LLMQType llmqType,
gsl::not_null<const CBlockIndex*> pQuorumBaseBlockIndex,
Expand Down
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