From a02f8302d953164685b3185aae5792982e6b5f3f Mon Sep 17 00:00:00 2001
From: UdjinM6 <UdjinM6@users.noreply.github.com>
Date: Tue, 18 May 2021 23:29:51 +0300
Subject: [PATCH] instantsend: Postpone mempool related cleanup fixes until
 dip0020 activation (#4159)

* instantsend: Upgrade IS db on dip0020 activation

* instantsend: Do not remove islocks for txes removed from mempool until dip0020 is activated

* refactor: introduce fUpgradedDB to avoid excessive locking and checking the state

* llmq: Decouple `fUpgradedDB` from `cs`

* Update src/llmq/quorums_instantsend.cpp

Co-authored-by: dustinface <35775977+xdustinface@users.noreply.github.com>

* Fix deadlock

Upgrade locks cs_main via GetTransaction

Co-authored-by: xdustinface <xdustinfacex@gmail.com>
Co-authored-by: dustinface <35775977+xdustinface@users.noreply.github.com>
---
 src/llmq/quorums_instantsend.cpp | 11 +++++++++--
 src/llmq/quorums_instantsend.h   |  6 ++++--
 2 files changed, 13 insertions(+), 4 deletions(-)

diff --git a/src/llmq/quorums_instantsend.cpp b/src/llmq/quorums_instantsend.cpp
index 2d1e26557b..a6e96aca84 100644
--- a/src/llmq/quorums_instantsend.cpp
+++ b/src/llmq/quorums_instantsend.cpp
@@ -52,7 +52,6 @@ uint256 CInstantSendLock::GetRequestId() const
 
 CInstantSendDb::CInstantSendDb(CDBWrapper& _db) : db(_db)
 {
-    Upgrade();
 }
 
 void CInstantSendDb::Upgrade()
@@ -1072,7 +1071,7 @@ void CInstantSendManager::TransactionAddedToMempool(const CTransactionRef& tx)
 
 void CInstantSendManager::TransactionRemovedFromMempool(const CTransactionRef& tx)
 {
-    if (tx->vin.empty()) {
+    if (tx->vin.empty() || !fUpgradedDB) {
         return;
     }
 
@@ -1217,6 +1216,14 @@ void CInstantSendManager::NotifyChainLock(const CBlockIndex* pindexChainLock)
 
 void CInstantSendManager::UpdatedBlockTip(const CBlockIndex* pindexNew)
 {
+    if (!fUpgradedDB) {
+        LOCK(cs_main);
+        if (VersionBitsState(pindexNew, Params().GetConsensus(), Consensus::DEPLOYMENT_DIP0020, versionbitscache) == ThresholdState::ACTIVE) {
+            db.Upgrade();
+            fUpgradedDB = true;
+        }
+    }
+
     bool fDIP0008Active = pindexNew->pprev && pindexNew->pprev->nHeight >= Params().GetConsensus().DIP0008Height;
 
     if (AreChainLocksEnabled() && fDIP0008Active) {
diff --git a/src/llmq/quorums_instantsend.h b/src/llmq/quorums_instantsend.h
index f7850a582d..7b963ab36d 100644
--- a/src/llmq/quorums_instantsend.h
+++ b/src/llmq/quorums_instantsend.h
@@ -55,11 +55,11 @@ private:
     void WriteInstantSendLockMined(CDBBatch& batch, const uint256& hash, int nHeight);
     void RemoveInstantSendLockMined(CDBBatch& batch, const uint256& hash, int nHeight);
 
-    void Upgrade();
-
 public:
     explicit CInstantSendDb(CDBWrapper& _db);
 
+    void Upgrade();
+
     void WriteNewInstantSendLock(const uint256& hash, const CInstantSendLock& islock);
     void RemoveInstantSendLock(CDBBatch& batch, const uint256& hash, CInstantSendLockPtr islock, bool keep_cache = true);
 
@@ -87,6 +87,8 @@ private:
     mutable CCriticalSection cs;
     CInstantSendDb db;
 
+    std::atomic<bool> fUpgradedDB{false};
+
     std::thread workThread;
     CThreadInterrupt workInterrupt;