diff --git a/src/librbd/mirroring_watcher/Types.cc b/src/librbd/mirroring_watcher/Types.cc
index 55e29c97fe1..f81b4ba693a 100644
--- a/src/librbd/mirroring_watcher/Types.cc
+++ b/src/librbd/mirroring_watcher/Types.cc
@@ -2,9 +2,159 @@
 // vim: ts=8 sw=2 smarttab
 
 #include "librbd/mirroring_watcher/Types.h"
+#include "include/assert.h"
+#include "include/stringify.h"
+#include "common/Formatter.h"
 
 namespace librbd {
 namespace mirroring_watcher {
 
+namespace {
+
+class EncodePayloadVisitor : public boost::static_visitor<void> {
+public:
+  explicit EncodePayloadVisitor(bufferlist &bl) : m_bl(bl) {}
+
+  template <typename Payload>
+  inline void operator()(const Payload &payload) const {
+    ::encode(static_cast<uint32_t>(Payload::NOTIFY_OP), m_bl);
+    payload.encode(m_bl);
+  }
+
+private:
+  bufferlist &m_bl;
+};
+
+class DecodePayloadVisitor : public boost::static_visitor<void> {
+public:
+  DecodePayloadVisitor(__u8 version, bufferlist::iterator &iter)
+    : m_version(version), m_iter(iter) {}
+
+  template <typename Payload>
+  inline void operator()(Payload &payload) const {
+    payload.decode(m_version, m_iter);
+  }
+
+private:
+  __u8 m_version;
+  bufferlist::iterator &m_iter;
+};
+
+class DumpPayloadVisitor : public boost::static_visitor<void> {
+public:
+  explicit DumpPayloadVisitor(Formatter *formatter) : m_formatter(formatter) {}
+
+  template <typename Payload>
+  inline void operator()(const Payload &payload) const {
+    NotifyOp notify_op = Payload::NOTIFY_OP;
+    m_formatter->dump_string("notify_op", stringify(notify_op));
+    payload.dump(m_formatter);
+  }
+
+private:
+  ceph::Formatter *m_formatter;
+};
+
+} // anonymous namespace
+
+void ModeUpdatedPayload::encode(bufferlist &bl) const {
+  ::encode(static_cast<uint32_t>(mirror_mode), bl);
+}
+
+void ModeUpdatedPayload::decode(__u8 version, bufferlist::iterator &iter) {
+  uint32_t mirror_mode_decode;
+  ::decode(mirror_mode_decode, iter);
+  mirror_mode = static_cast<cls::rbd::MirrorMode>(mirror_mode_decode);
+}
+
+void ModeUpdatedPayload::dump(Formatter *f) const {
+  f->dump_stream("mirror_mode") << mirror_mode;
+}
+
+void ImageUpdatedPayload::encode(bufferlist &bl) const {
+  ::encode(static_cast<uint32_t>(mirror_image_state), bl);
+  ::encode(image_id, bl);
+  ::encode(global_image_id, bl);
+}
+
+void ImageUpdatedPayload::decode(__u8 version, bufferlist::iterator &iter) {
+  uint32_t mirror_image_state_decode;
+  ::decode(mirror_image_state_decode, iter);
+  mirror_image_state = static_cast<cls::rbd::MirrorImageState>(
+    mirror_image_state_decode);
+  ::decode(image_id, iter);
+  ::decode(global_image_id, iter);
+}
+
+void ImageUpdatedPayload::dump(Formatter *f) const {
+  f->dump_stream("mirror_image_state") << mirror_image_state;
+  f->dump_string("image_id", image_id);
+  f->dump_string("global_image_id", global_image_id);
+}
+
+void UnknownPayload::encode(bufferlist &bl) const {
+  assert(false);
+}
+
+void UnknownPayload::decode(__u8 version, bufferlist::iterator &iter) {
+}
+
+void UnknownPayload::dump(Formatter *f) const {
+}
+
+void NotifyMessage::encode(bufferlist& bl) const {
+  ENCODE_START(1, 1, bl);
+  boost::apply_visitor(EncodePayloadVisitor(bl), payload);
+  ENCODE_FINISH(bl);
+}
+
+void NotifyMessage::decode(bufferlist::iterator& iter) {
+  DECODE_START(1, iter);
+
+  uint32_t notify_op;
+  ::decode(notify_op, iter);
+
+  // select the correct payload variant based upon the encoded op
+  switch (notify_op) {
+  case NOTIFY_OP_MODE_UPDATED:
+    payload = ModeUpdatedPayload();
+    break;
+  case NOTIFY_OP_IMAGE_UPDATED:
+    payload = ImageUpdatedPayload();
+    break;
+  default:
+    payload = UnknownPayload();
+    break;
+  }
+
+  apply_visitor(DecodePayloadVisitor(struct_v, iter), payload);
+  DECODE_FINISH(iter);
+}
+
+void NotifyMessage::dump(Formatter *f) const {
+  apply_visitor(DumpPayloadVisitor(f), payload);
+}
+
+void NotifyMessage::generate_test_instances(std::list<NotifyMessage *> &o) {
+  o.push_back(new NotifyMessage(ModeUpdatedPayload(cls::rbd::MIRROR_MODE_DISABLED)));
+  o.push_back(new NotifyMessage(ImageUpdatedPayload(cls::rbd::MIRROR_IMAGE_STATE_DISABLING,
+                                                    "image id", "global image id")));
+}
+
+std::ostream &operator<<(std::ostream &out, const NotifyOp &op) {
+  switch (op) {
+  case NOTIFY_OP_MODE_UPDATED:
+    out << "ModeUpdated";
+    break;
+  case NOTIFY_OP_IMAGE_UPDATED:
+    out << "ImageUpdated";
+    break;
+  default:
+    out << "Unknown (" << static_cast<uint32_t>(op) << ")";
+    break;
+  }
+  return out;
+}
+
 } // namespace mirroring_watcher
 } // namespace librbd
diff --git a/src/librbd/mirroring_watcher/Types.h b/src/librbd/mirroring_watcher/Types.h
index 4e4dcf4452b..16bf5b65e47 100644
--- a/src/librbd/mirroring_watcher/Types.h
+++ b/src/librbd/mirroring_watcher/Types.h
@@ -5,11 +5,98 @@
 #define CEPH_LIBRBD_MIRRORING_WATCHER_TYPES_H
 
 #include "include/int_types.h"
+#include "include/buffer_fwd.h"
+#include "include/encoding.h"
+#include "cls/rbd/cls_rbd_types.h"
+#include <iosfwd>
+#include <list>
+#include <string>
+#include <boost/variant.hpp>
+
+namespace ceph { class Formatter; }
 
 namespace librbd {
 namespace mirroring_watcher {
 
+enum NotifyOp {
+  NOTIFY_OP_MODE_UPDATED  = 0,
+  NOTIFY_OP_IMAGE_UPDATED = 1
+};
+
+struct ModeUpdatedPayload {
+  static const NotifyOp NOTIFY_OP = NOTIFY_OP_MODE_UPDATED;
+
+  cls::rbd::MirrorMode mirror_mode = cls::rbd::MIRROR_MODE_DISABLED;
+
+  ModeUpdatedPayload() {
+  }
+  ModeUpdatedPayload(cls::rbd::MirrorMode mirror_mode)
+    : mirror_mode(mirror_mode) {
+  }
+
+  void encode(bufferlist &bl) const;
+  void decode(__u8 version, bufferlist::iterator &iter);
+  void dump(Formatter *f) const;
+};
+
+struct ImageUpdatedPayload {
+  static const NotifyOp NOTIFY_OP = NOTIFY_OP_IMAGE_UPDATED;
+
+  cls::rbd::MirrorImageState mirror_image_state =
+    cls::rbd::MIRROR_IMAGE_STATE_ENABLED;
+  std::string image_id;
+  std::string global_image_id;
+
+  ImageUpdatedPayload() {
+  }
+  ImageUpdatedPayload(cls::rbd::MirrorImageState mirror_image_state,
+                      const std::string &image_id,
+                      const std::string &global_image_id)
+    : mirror_image_state(mirror_image_state), image_id(image_id),
+      global_image_id(global_image_id) {
+  }
+
+  void encode(bufferlist &bl) const;
+  void decode(__u8 version, bufferlist::iterator &iter);
+  void dump(Formatter *f) const;
+};
+
+struct UnknownPayload {
+  static const NotifyOp NOTIFY_OP = static_cast<NotifyOp>(-1);
+
+  UnknownPayload() {
+  }
+
+  void encode(bufferlist &bl) const;
+  void decode(__u8 version, bufferlist::iterator &iter);
+  void dump(Formatter *f) const;
+};
+
+typedef boost::variant<ModeUpdatedPayload,
+                       ImageUpdatedPayload,
+                       UnknownPayload> Payload;
+
+struct NotifyMessage {
+  NotifyMessage(const Payload &payload = UnknownPayload()) : payload(payload) {
+  }
+
+  Payload payload;
+
+  void encode(bufferlist& bl) const;
+  void decode(bufferlist::iterator& it);
+  void dump(Formatter *f) const;
+
+  static void generate_test_instances(std::list<NotifyMessage *> &o);
+};
+
+WRITE_CLASS_ENCODER(NotifyMessage);
+
+std::ostream &operator<<(std::ostream &out, const NotifyOp &op);
+
 } // namespace mirroring_watcher
 } // namespace librbd
 
+using librbd::mirroring_watcher::encode;
+using librbd::mirroring_watcher::decode;
+
 #endif // CEPH_LIBRBD_MIRRORING_WATCHER_TYPES_H
diff --git a/src/test/encoding/types.h b/src/test/encoding/types.h
index 382c0a35a40..11dfc503510 100644
--- a/src/test/encoding/types.h
+++ b/src/test/encoding/types.h
@@ -245,6 +245,8 @@ TYPE_FEATUREFUL(EUpdate)
 TYPE(librbd::journal::EventEntry)
 TYPE(librbd::journal::ClientData)
 TYPE(librbd::journal::TagData)
+#include "librbd/mirroring_watcher/Types.h"
+TYPE(librbd::mirroring_watcher::NotifyMessage)
 #include "librbd/WatchNotifyTypes.h"
 TYPE(librbd::watch_notify::NotifyMessage)
 TYPE(librbd::watch_notify::ResponseMessage)