diff --git a/src/auth/cephx/CephxSessionHandler.cc b/src/auth/cephx/CephxSessionHandler.cc
index b2d402d2af3..defc4edda37 100644
--- a/src/auth/cephx/CephxSessionHandler.cc
+++ b/src/auth/cephx/CephxSessionHandler.cc
@@ -31,7 +31,7 @@ int CephxSessionHandler::sign_message(Message *m)
     return 0;
   }
   bufferlist bl_plaintext, bl_encrypted;
-  ceph_msg_header header = m->get_header();
+  const ceph_msg_header& header = m->get_header();
   std::string error;
 
   ceph_msg_footer& en_footer = m->get_footer();
@@ -77,8 +77,8 @@ int CephxSessionHandler::check_message_signature(Message *m)
 
   bufferlist bl_plaintext, bl_ciphertext;
   std::string sig_error;
-  ceph_msg_header& header = m->get_header();
-  ceph_msg_footer& footer = m->get_footer();
+  const ceph_msg_header& header = m->get_header();
+  const ceph_msg_footer& footer = m->get_footer();
 
   if ((features & CEPH_FEATURE_MSG_AUTH) == 0) {
     // it's fine, we didn't negotiate this feature.
diff --git a/src/common/HeartbeatMap.cc b/src/common/HeartbeatMap.cc
index 9787f737cef..2c58276196a 100644
--- a/src/common/HeartbeatMap.cc
+++ b/src/common/HeartbeatMap.cc
@@ -41,7 +41,7 @@ HeartbeatMap::~HeartbeatMap()
   assert(m_workers.empty());
 }
 
-heartbeat_handle_d *HeartbeatMap::add_worker(string name)
+heartbeat_handle_d *HeartbeatMap::add_worker(const string& name)
 {
   m_rwlock.get_write();
   ldout(m_cct, 10) << "add_worker '" << name << "'" << dendl;
@@ -52,7 +52,7 @@ heartbeat_handle_d *HeartbeatMap::add_worker(string name)
   return h;
 }
 
-void HeartbeatMap::remove_worker(heartbeat_handle_d *h)
+void HeartbeatMap::remove_worker(const heartbeat_handle_d *h)
 {
   m_rwlock.get_write();
   ldout(m_cct, 10) << "remove_worker '" << h->name << "'" << dendl;
@@ -61,7 +61,7 @@ void HeartbeatMap::remove_worker(heartbeat_handle_d *h)
   delete h;
 }
 
-bool HeartbeatMap::_check(heartbeat_handle_d *h, const char *who, time_t now)
+bool HeartbeatMap::_check(const heartbeat_handle_d *h, const char *who, time_t now)
 {
   bool healthy = true;
   time_t was;
diff --git a/src/common/HeartbeatMap.h b/src/common/HeartbeatMap.h
index a4aee48a191..5513e186c2a 100644
--- a/src/common/HeartbeatMap.h
+++ b/src/common/HeartbeatMap.h
@@ -41,7 +41,7 @@ namespace ceph {
  */
 
 struct heartbeat_handle_d {
-  std::string name;
+  const std::string name;
   atomic_t timeout, suicide_timeout;
   time_t grace, suicide_grace;
   std::list<heartbeat_handle_d*>::iterator list_item;
@@ -54,8 +54,8 @@ struct heartbeat_handle_d {
 class HeartbeatMap {
  public:
   // register/unregister
-  heartbeat_handle_d *add_worker(std::string name);
-  void remove_worker(heartbeat_handle_d *h);
+  heartbeat_handle_d *add_worker(const std::string& name);
+  void remove_worker(const heartbeat_handle_d *h);
 
   // reset the timeout so that it expects another touch within grace amount of time
   void reset_timeout(heartbeat_handle_d *h, time_t grace, time_t suicide_grace);
@@ -77,7 +77,7 @@ class HeartbeatMap {
   time_t m_inject_unhealthy_until;
   std::list<heartbeat_handle_d*> m_workers;
 
-  bool _check(heartbeat_handle_d *h, const char *who, time_t now);
+  bool _check(const heartbeat_handle_d *h, const char *who, time_t now);
 };
 
 }
diff --git a/src/common/RefCountedObj.h b/src/common/RefCountedObj.h
index 729bbb9fd4b..3755018f801 100644
--- a/src/common/RefCountedObj.h
+++ b/src/common/RefCountedObj.h
@@ -52,7 +52,7 @@ public:
     cct = c;
   }
 
-  uint64_t get_nref() {
+  uint64_t get_nref() const {
     return nref.read();
   }
 };
diff --git a/src/librados/ListObjectImpl.h b/src/librados/ListObjectImpl.h
index fdbe509d154..fe52f68075a 100644
--- a/src/librados/ListObjectImpl.h
+++ b/src/librados/ListObjectImpl.h
@@ -28,9 +28,9 @@ struct ListObjectImpl {
   ListObjectImpl(std::string n, std::string o, std::string l):
       nspace(n), oid(o), locator(l) {}
 
-  const std::string& get_nspace() { return nspace; }
-  const std::string& get_oid() { return oid; }
-  const std::string& get_locator() { return locator; }
+  const std::string& get_nspace() const { return nspace; }
+  const std::string& get_oid() const { return oid; }
+  const std::string& get_locator() const { return locator; }
 };
 WRITE_EQ_OPERATORS_3(ListObjectImpl, nspace, oid, locator)
 WRITE_CMP_OPERATORS_3(ListObjectImpl, nspace, oid, locator)
diff --git a/src/msg/Message.h b/src/msg/Message.h
index c2cd1238150..ddba0e57a89 100644
--- a/src/msg/Message.h
+++ b/src/msg/Message.h
@@ -313,15 +313,17 @@ public:
   Throttle *get_message_throttler() { return msg_throttler; }
 
   void set_dispatch_throttle_size(uint64_t s) { dispatch_throttle_size = s; }
-  uint64_t get_dispatch_throttle_size() { return dispatch_throttle_size; }
+  uint64_t get_dispatch_throttle_size() const { return dispatch_throttle_size; }
 
+  const ceph_msg_header &get_header() const { return header; }
   ceph_msg_header &get_header() { return header; }
   void set_header(const ceph_msg_header &e) { header = e; }
   void set_footer(const ceph_msg_footer &e) { footer = e; }
+  const ceph_msg_footer &get_footer() const { return footer; }
   ceph_msg_footer &get_footer() { return footer; }
   void set_src(const entity_name_t& src) { header.src = src; }
 
-  uint32_t get_magic() { return magic; }
+  uint32_t get_magic() const { return magic; }
   void set_magic(int _magic) { magic = _magic; }
 
   /*
@@ -346,7 +348,7 @@ public:
     clear_buffers(); // let subclass drop buffers as well
   }
 
-  bool empty_payload() { return payload.length() == 0; }
+  bool empty_payload() const { return payload.length() == 0; }
   bufferlist& get_payload() { return payload; }
   void set_payload(bufferlist& bl) {
     if (byte_throttler)
diff --git a/src/msg/async/AsyncConnection.cc b/src/msg/async/AsyncConnection.cc
index a0deea1f2d4..0efb11107e7 100644
--- a/src/msg/async/AsyncConnection.cc
+++ b/src/msg/async/AsyncConnection.cc
@@ -2174,7 +2174,7 @@ int AsyncConnection::_send(Message *m)
   return rc;
 }
 
-int AsyncConnection::write_message(ceph_msg_header& header, ceph_msg_footer& footer,
+int AsyncConnection::write_message(const ceph_msg_header& header, const ceph_msg_footer& footer,
                                   bufferlist& blist)
 {
   bufferlist bl;
diff --git a/src/msg/async/AsyncConnection.h b/src/msg/async/AsyncConnection.h
index da2aad1e4f4..91c1d6581ac 100644
--- a/src/msg/async/AsyncConnection.h
+++ b/src/msg/async/AsyncConnection.h
@@ -63,7 +63,7 @@ class AsyncConnection : public Connection {
   int randomize_out_seq();
   void handle_ack(uint64_t seq);
   void _send_keepalive_or_ack(bool ack=false, utime_t *t=NULL);
-  int write_message(ceph_msg_header& header, ceph_msg_footer& footer, bufferlist& blist);
+  int write_message(const ceph_msg_header& header, const ceph_msg_footer& footer, bufferlist& blist);
   int _reply_accept(char tag, ceph_msg_connect &connect, ceph_msg_connect_reply &reply,
                     bufferlist authorizer_reply) {
     bufferlist reply_bl;
@@ -203,7 +203,6 @@ class AsyncConnection : public Connection {
       return statenames[state];
   }
 
-  CephContext *cc;
   AsyncMessenger *async_msgr;
   int global_seq;
   __u32 connect_seq, peer_global_seq;
diff --git a/src/msg/simple/Pipe.cc b/src/msg/simple/Pipe.cc
index 74f2c876218..7ebb6297b45 100644
--- a/src/msg/simple/Pipe.cc
+++ b/src/msg/simple/Pipe.cc
@@ -1798,8 +1798,8 @@ void Pipe::writer()
 	m->encode(features, msgr->crcflags);
 
 	// prepare everything
-	ceph_msg_header& header = m->get_header();
-	ceph_msg_footer& footer = m->get_footer();
+	const ceph_msg_header& header = m->get_header();
+	const ceph_msg_footer& footer = m->get_footer();
 
 	// Now that we have all the crcs calculated, handle the
 	// digital signature for the message, if the pipe has session
@@ -2237,7 +2237,7 @@ int Pipe::write_keepalive2(char tag, const utime_t& t)
 }
 
 
-int Pipe::write_message(ceph_msg_header& header, ceph_msg_footer& footer, bufferlist& blist)
+int Pipe::write_message(const ceph_msg_header& header, const ceph_msg_footer& footer, bufferlist& blist)
 {
   int ret;
 
diff --git a/src/msg/simple/Pipe.h b/src/msg/simple/Pipe.h
index 9b464a5065b..ddfa99f78af 100644
--- a/src/msg/simple/Pipe.h
+++ b/src/msg/simple/Pipe.h
@@ -230,7 +230,7 @@ class DispatchQueue;
 
     int read_message(Message **pm,
 		     AuthSessionHandler *session_security_copy);
-    int write_message(ceph_msg_header& h, ceph_msg_footer& f, bufferlist& body);
+    int write_message(const ceph_msg_header& h, const ceph_msg_footer& f, bufferlist& body);
     /**
      * Write the given data (of length len) to the Pipe's socket. This function
      * will loop until all passed data has been written out.