diff --git a/src/addrman.h b/src/addrman.h
index cabacbbea..76e7b210f 100644
--- a/src/addrman.h
+++ b/src/addrman.h
@@ -482,6 +482,7 @@ public:
     //! Return the number of (unique) addresses in all tables.
     size_t size() const
     {
+        LOCK(cs); // TODO: Cache this in an atomic to avoid this overhead
         return vRandom.size();
     }
 
@@ -501,13 +502,11 @@ public:
     //! Add a single address.
     bool Add(const CAddress &addr, const CNetAddr& source, int64_t nTimePenalty = 0)
     {
+        LOCK(cs);
         bool fRet = false;
-        {
-            LOCK(cs);
-            Check();
-            fRet |= Add_(addr, source, nTimePenalty);
-            Check();
-        }
+        Check();
+        fRet |= Add_(addr, source, nTimePenalty);
+        Check();
         if (fRet)
             LogPrint("addrman", "Added %s from %s: %i tried, %i new\n", addr.ToStringIPPort(), source.ToString(), nTried, nNew);
         return fRet;
@@ -516,14 +515,12 @@ public:
     //! Add multiple addresses.
     bool Add(const std::vector<CAddress> &vAddr, const CNetAddr& source, int64_t nTimePenalty = 0)
     {
+        LOCK(cs);
         int nAdd = 0;
-        {
-            LOCK(cs);
-            Check();
-            for (std::vector<CAddress>::const_iterator it = vAddr.begin(); it != vAddr.end(); it++)
-                nAdd += Add_(*it, source, nTimePenalty) ? 1 : 0;
-            Check();
-        }
+        Check();
+        for (std::vector<CAddress>::const_iterator it = vAddr.begin(); it != vAddr.end(); it++)
+            nAdd += Add_(*it, source, nTimePenalty) ? 1 : 0;
+        Check();
         if (nAdd)
             LogPrint("addrman", "Added %i addresses from %s: %i tried, %i new\n", nAdd, source.ToString(), nTried, nNew);
         return nAdd > 0;
@@ -532,23 +529,19 @@ public:
     //! Mark an entry as accessible.
     void Good(const CService &addr, int64_t nTime = GetAdjustedTime())
     {
-        {
-            LOCK(cs);
-            Check();
-            Good_(addr, nTime);
-            Check();
-        }
+        LOCK(cs);
+        Check();
+        Good_(addr, nTime);
+        Check();
     }
 
     //! Mark an entry as connection attempted to.
     void Attempt(const CService &addr, bool fCountFailure, int64_t nTime = GetAdjustedTime())
     {
-        {
-            LOCK(cs);
-            Check();
-            Attempt_(addr, fCountFailure, nTime);
-            Check();
-        }
+        LOCK(cs);
+        Check();
+        Attempt_(addr, fCountFailure, nTime);
+        Check();
     }
 
     /**
@@ -582,12 +575,10 @@ public:
     //! Mark an entry as currently-connected-to.
     void Connected(const CService &addr, int64_t nTime = GetAdjustedTime())
     {
-        {
-            LOCK(cs);
-            Check();
-            Connected_(addr, nTime);
-            Check();
-        }
+        LOCK(cs);
+        Check();
+        Connected_(addr, nTime);
+        Check();
     }
 
     void SetServices(const CService &addr, ServiceFlags nServices)
diff --git a/src/net.h b/src/net.h
index 12d438996..0f451c075 100644
--- a/src/net.h
+++ b/src/net.h
@@ -707,7 +707,7 @@ public:
     const bool fInbound;
     bool fNetworkNode;
     std::atomic_bool fSuccessfullyConnected;
-    bool fDisconnect;
+    std::atomic_bool fDisconnect;
     // We use fRelayTxes for two purposes -
     // a) it allows us to not relay tx invs before receiving the peer's version message
     // b) the peer may tell us in its version message that we should not relay tx invs
diff --git a/src/validation.cpp b/src/validation.cpp
index d9ed9e8f2..8f0ebefe5 100644
--- a/src/validation.cpp
+++ b/src/validation.cpp
@@ -71,7 +71,7 @@ CBlockIndex *pindexBestHeader = NULL;
 CWaitableCriticalSection csBestBlock;
 CConditionVariable cvBlockChange;
 int nScriptCheckThreads = 0;
-bool fImporting = false;
+std::atomic_bool fImporting(false);
 bool fReindex = false;
 bool fTxIndex = true;
 bool fAddressIndex = false;
diff --git a/src/validation.h b/src/validation.h
index efb916146..3218b83f9 100644
--- a/src/validation.h
+++ b/src/validation.h
@@ -163,7 +163,7 @@ extern uint64_t nLastBlockSize;
 extern const std::string strMessageMagic;
 extern CWaitableCriticalSection csBestBlock;
 extern CConditionVariable cvBlockChange;
-extern bool fImporting;
+extern std::atomic_bool fImporting;
 extern bool fReindex;
 extern int nScriptCheckThreads;
 extern bool fTxIndex;