From 677aa3d88c018a235d5b6d929e82f7b16e4f3e41 Mon Sep 17 00:00:00 2001
From: Matt Corallo <git@bluematt.me>
Date: Thu, 22 Oct 2015 11:52:55 -0700
Subject: [PATCH] Discard txn cache entries that were loaded for removed
 mempool txn

---
 src/main.cpp | 23 +++++++++++++++--------
 1 file changed, 15 insertions(+), 8 deletions(-)

diff --git a/src/main.cpp b/src/main.cpp
index e9e982043..73ca8bb05 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -789,6 +789,17 @@ bool CheckTransaction(const CTransaction& tx, CValidationState &state)
     return true;
 }
 
+void LimitMempoolSize(CTxMemPool& pool, size_t limit, unsigned long age) {
+    int expired = pool.Expire(GetTime() - age);
+    if (expired != 0)
+        LogPrint("mempool", "Expired %i transactions from the memory pool\n", expired);
+
+    std::vector<uint256> vNoSpendsRemaining;
+    pool.TrimToSize(limit, &vNoSpendsRemaining);
+    BOOST_FOREACH(const uint256& removed, vNoSpendsRemaining)
+        pcoinsTip->Uncache(removed);
+}
+
 CAmount GetMinRelayFee(const CTransaction& tx, const CTxMemPool& pool, unsigned int nBytes, bool fAllowFree)
 {
     uint256 hash = tx.GetHash();
@@ -1210,12 +1221,8 @@ bool AcceptToMemoryPool(CTxMemPool& pool, CValidationState &state, const CTransa
 
         // trim mempool and check if tx was trimmed
         if (!fOverrideMempoolLimit) {
-            int expired = pool.Expire(GetTime() - GetArg("-mempoolexpiry", DEFAULT_MEMPOOL_EXPIRY) * 60 * 60);
-            if (expired != 0)
-                LogPrint("mempool", "Expired %i transactions from the memory pool\n", expired);
-
-            pool.TrimToSize(GetArg("-maxmempool", DEFAULT_MAX_MEMPOOL_SIZE) * 1000000);
-            if (!pool.exists(tx.GetHash()))
+            LimitMempoolSize(pool, GetArg("-maxmempool", DEFAULT_MAX_MEMPOOL_SIZE) * 1000000, GetArg("-mempoolexpiry", DEFAULT_MEMPOOL_EXPIRY) * 60 * 60);
+            if (!pool.exists(hash))
                 return state.DoS(0, false, REJECT_INSUFFICIENTFEE, "mempool full");
         }
     }
@@ -2571,7 +2578,7 @@ static bool ActivateBestChainStep(CValidationState& state, const CChainParams& c
 
     if (fBlocksDisconnected) {
         mempool.removeForReorg(pcoinsTip, chainActive.Tip()->nHeight + 1, STANDARD_LOCKTIME_VERIFY_FLAGS);
-        mempool.TrimToSize(GetArg("-maxmempool", DEFAULT_MAX_MEMPOOL_SIZE) * 1000000);
+        LimitMempoolSize(mempool, GetArg("-maxmempool", DEFAULT_MAX_MEMPOOL_SIZE) * 1000000, GetArg("-mempoolexpiry", DEFAULT_MEMPOOL_EXPIRY) * 60 * 60);
     }
     mempool.check(pcoinsTip);
 
@@ -2686,7 +2693,7 @@ bool InvalidateBlock(CValidationState& state, const Consensus::Params& consensus
         }
     }
 
-    mempool.TrimToSize(GetArg("-maxmempool", DEFAULT_MAX_MEMPOOL_SIZE) * 1000000);
+    LimitMempoolSize(mempool, GetArg("-maxmempool", DEFAULT_MAX_MEMPOOL_SIZE) * 1000000, GetArg("-mempoolexpiry", DEFAULT_MEMPOOL_EXPIRY) * 60 * 60);
 
     // The resulting new best tip may not be in setBlockIndexCandidates anymore, so
     // add it again.