Few more lock-related fixes:

- do not lock cs_main for mnodeman.CheckAndRemove() - we have trylock inside CMasternode.Check, should be enough
- fast cs_main lock for ix
- use RelayInv instead of manually locking nodes / pushing inv
- do not lock cs_vNodes / ClearFulfilledRequest on every 100th block, CMasternodeSync should already handle resync by itself better now

src/darksend.cpp

@@ -2219,16 +2219,7 @@ void ThreadCheckDarkSendPool()
 
             if(c % 60 == 0)
             {
-                {
-                    LOCK(cs_main);
-                    /*
-                        cs_main is required for doing CMasternode.Check because something
-                        is modifying the coins view without a mempool lock. It causes
-                        segfaults from this code without the cs_main lock.
-                    */
-                    mnodeman.CheckAndRemove();
-                }
-
+                mnodeman.CheckAndRemove();
                 mnodeman.ProcessMasternodeConnections();
                 masternodePayments.CleanPaymentList();
                 CleanTransactionLocksList();

src/instantx.cpp

@@ -70,14 +70,14 @@ void ProcessMessageInstantX(CNode* pfrom, std::string& strCommand, CDataStream&
         bool fMissingInputs = false;
         CValidationState state;
 
-        LOCK(cs_main);
-        if (AcceptToMemoryPool(mempool, state, tx, true, &fMissingInputs))
+        bool fAccepted = false;
         {
-            vector<CInv> vInv;
-            vInv.push_back(inv);
-            LOCK(cs_vNodes);
-            BOOST_FOREACH(CNode* pnode, vNodes)
-                pnode->PushMessage("inv", vInv);
+            LOCK(cs_main);
+            fAccepted = AcceptToMemoryPool(mempool, state, tx, true, &fMissingInputs);
+        }
+        if (fAccepted)
+        {
+            RelayInv(inv);
 
             DoConsensusVote(tx, nBlockHeight);
 
@@ -161,12 +161,7 @@ void ProcessMessageInstantX(CNode* pfrom, std::string& strCommand, CDataStream&
                     mapUnknownVotes[ctx.vinMasternode.prevout.hash] = GetTime()+(60*10);
                 }
             }
-            vector<CInv> vInv;
-            vInv.push_back(inv);
-            LOCK(cs_vNodes);
-            BOOST_FOREACH(CNode* pnode, vNodes)
-                pnode->PushMessage("inv", vInv);
-
+            RelayInv(inv);
         }
 
         return;

src/main.cpp

@@ -3279,22 +3279,9 @@ bool ProcessNewBlock(CValidationState &state, CNode* pfrom, CBlock* pblock, CDis
 
     if(!fLiteMode){
         if (masternodeSync.RequestedMasternodeAssets > MASTERNODE_SYNC_LIST) {
-            CScript payee;
-            CTxIn vin;
             darkSendPool.NewBlock();
             masternodePayments.ProcessBlock(GetHeight()+10);
             budget.NewBlock();
-
-            //allow clients to ask for syncing again if they need it
-            if(GetHeight() % 100 == 0) {
-                LOCK(cs_vNodes);
-                BOOST_FOREACH(CNode* pnode, vNodes) {
-                    pnode->ClearFulfilledRequest("getspork");
-                    pnode->ClearFulfilledRequest("mnsync");
-                    pnode->ClearFulfilledRequest("mnwsync");
-                    pnode->ClearFulfilledRequest("busync");
-                }                
-            }
         }
     }