rbd-mirror: extract journal local image creation to new state machine

This state machine simplifies the existing bootstrap state machine steps
in that it will always unregister as a first step (might not be registered).
It also take advantage of the previous fix for REPLAYING vs SYNCING state
so that it always uses an initial SYNCING state.

Signed-off-by: Jason Dillaman <dillaman@redhat.com>

src/test/rbd_mirror/CMakeLists.txt

@@ -38,6 +38,7 @@ add_executable(unittest_rbd_mirror
   image_replayer/test_mock_GetMirrorImageIdRequest.cc
   image_replayer/test_mock_PrepareLocalImageRequest.cc
   image_replayer/test_mock_PrepareRemoteImageRequest.cc
+  image_replayer/journal/test_mock_CreateLocalImageRequest.cc
   image_replayer/journal/test_mock_EventPreprocessor.cc
   image_replayer/journal/test_mock_Replayer.cc
   image_sync/test_mock_SyncPointCreateRequest.cc

src/test/rbd_mirror/image_replayer/journal/test_mock_CreateLocalImageRequest.cc

@@ -0,0 +1,362 @@
+// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
+// vim: ts=8 sw=2 smarttab
+
+#include "test/rbd_mirror/test_mock_fixture.h"
+#include "librbd/journal/Types.h"
+#include "librbd/journal/TypeTraits.h"
+#include "tools/rbd_mirror/Threads.h"
+#include "tools/rbd_mirror/image_replayer/CreateImageRequest.h"
+#include "tools/rbd_mirror/image_replayer/journal/CreateLocalImageRequest.h"
+#include "test/journal/mock/MockJournaler.h"
+#include "test/librbd/mock/MockImageCtx.h"
+#include "test/rbd_mirror/mock/MockContextWQ.h"
+#include "test/rbd_mirror/mock/MockSafeTimer.h"
+#include <boost/intrusive_ptr.hpp>
+
+namespace librbd {
+
+namespace {
+
+struct MockTestImageCtx : public librbd::MockImageCtx {
+  explicit MockTestImageCtx(librbd::ImageCtx &image_ctx)
+    : librbd::MockImageCtx(image_ctx) {
+  }
+};
+
+} // anonymous namespace
+
+namespace journal {
+
+template <>
+struct TypeTraits<librbd::MockTestImageCtx> {
+  typedef ::journal::MockJournaler Journaler;
+};
+
+} // namespace journal
+
+namespace util {
+
+static std::string s_image_id;
+
+template <>
+std::string generate_image_id<MockTestImageCtx>(librados::IoCtx&) {
+  ceph_assert(!s_image_id.empty());
+  return s_image_id;
+}
+
+} // namespace util
+} // namespace librbd
+
+namespace rbd {
+namespace mirror {
+
+template <>
+struct Threads<librbd::MockTestImageCtx> {
+};
+
+namespace image_replayer {
+
+template<>
+struct CreateImageRequest<librbd::MockTestImageCtx> {
+  static CreateImageRequest* s_instance;
+  Context *on_finish = nullptr;
+
+  static CreateImageRequest* create(Threads<librbd::MockTestImageCtx>* threads,
+                                    librados::IoCtx &local_io_ctx,
+                                    const std::string &global_image_id,
+                                    const std::string &remote_mirror_uuid,
+                                    const std::string &local_image_name,
+				    const std::string &local_image_id,
+                                    librbd::MockTestImageCtx *remote_image_ctx,
+                                    Context *on_finish) {
+    ceph_assert(s_instance != nullptr);
+    s_instance->on_finish = on_finish;
+    s_instance->construct(local_image_id);
+    return s_instance;
+  }
+
+  CreateImageRequest() {
+    ceph_assert(s_instance == nullptr);
+    s_instance = this;
+  }
+  ~CreateImageRequest() {
+    s_instance = nullptr;
+  }
+
+  MOCK_METHOD1(construct, void(const std::string&));
+  MOCK_METHOD0(send, void());
+};
+
+CreateImageRequest<librbd::MockTestImageCtx>*
+  CreateImageRequest<librbd::MockTestImageCtx>::s_instance = nullptr;
+
+} // namespace image_replayer
+} // namespace mirror
+} // namespace rbd
+
+#include "tools/rbd_mirror/image_replayer/journal/CreateLocalImageRequest.cc"
+
+using ::testing::_;
+using ::testing::InSequence;
+using ::testing::Invoke;
+using ::testing::WithArg;
+
+namespace rbd {
+namespace mirror {
+namespace image_replayer {
+namespace journal {
+
+class TestMockImageReplayerJournalCreateLocalImageRequest : public TestMockFixture {
+public:
+  typedef CreateLocalImageRequest<librbd::MockTestImageCtx> MockCreateLocalImageRequest;
+  typedef Threads<librbd::MockTestImageCtx> MockThreads;
+  typedef CreateImageRequest<librbd::MockTestImageCtx> MockCreateImageRequest;
+
+  void SetUp() override {
+    TestMockFixture::SetUp();
+
+    librbd::RBD rbd;
+    ASSERT_EQ(0, create_image(rbd, m_remote_io_ctx, m_image_name, m_image_size));
+    ASSERT_EQ(0, open_image(m_remote_io_ctx, m_image_name, &m_remote_image_ctx));
+    m_mock_remote_image_ctx = new librbd::MockTestImageCtx(*m_remote_image_ctx);
+  }
+
+  void TearDown() override {
+    delete m_mock_remote_image_ctx;
+    TestMockFixture::TearDown();
+  }
+
+  void expect_journaler_register_client(
+      ::journal::MockJournaler& mock_journaler,
+      const librbd::journal::ClientData& client_data, int r) {
+    bufferlist bl;
+    encode(client_data, bl);
+
+    EXPECT_CALL(mock_journaler, register_client(ContentsEqual(bl), _))
+      .WillOnce(WithArg<1>(Invoke([this, r](Context *on_finish) {
+                                    m_threads->work_queue->queue(on_finish, r);
+                                  })));
+  }
+
+  void expect_journaler_unregister_client(
+      ::journal::MockJournaler& mock_journaler, int r) {
+    EXPECT_CALL(mock_journaler, unregister_client(_))
+      .WillOnce(Invoke([this, r](Context *on_finish) {
+                  m_threads->work_queue->queue(on_finish, r);
+                }));
+  }
+
+  void expect_journaler_update_client(
+      ::journal::MockJournaler& mock_journaler,
+      const librbd::journal::ClientData& client_data, int r) {
+    bufferlist bl;
+    encode(client_data, bl);
+
+    EXPECT_CALL(mock_journaler, update_client(ContentsEqual(bl), _))
+      .WillOnce(WithArg<1>(Invoke([this, r](Context *on_finish) {
+                                    m_threads->work_queue->queue(on_finish, r);
+                                  })));
+  }
+  void expect_create_image(MockCreateImageRequest& mock_create_image_request,
+                           const std::string& image_id, int r) {
+    EXPECT_CALL(mock_create_image_request, construct(image_id));
+    EXPECT_CALL(mock_create_image_request, send())
+      .WillOnce(Invoke([this, &mock_create_image_request, r]() {
+          m_threads->work_queue->queue(mock_create_image_request.on_finish, r);
+        }));
+  }
+
+  MockCreateLocalImageRequest* create_request(
+      MockThreads& mock_threads,
+      ::journal::MockJournaler& mock_journaler,
+      const std::string& global_image_id,
+      const std::string& remote_mirror_uuid,
+      librbd::journal::MirrorPeerClientMeta* mirror_peer_client_meta,
+      std::string* local_image_id, Context* on_finish) {
+    return new MockCreateLocalImageRequest(
+      &mock_threads, m_local_io_ctx, m_mock_remote_image_ctx,
+      &mock_journaler, global_image_id, remote_mirror_uuid,
+      mirror_peer_client_meta, nullptr, local_image_id, on_finish);
+  }
+
+  librbd::ImageCtx *m_remote_image_ctx;
+  librbd::MockTestImageCtx *m_mock_remote_image_ctx = nullptr;
+};
+
+TEST_F(TestMockImageReplayerJournalCreateLocalImageRequest, Success) {
+  InSequence seq;
+
+  // re-register the client
+  ::journal::MockJournaler mock_journaler;
+  expect_journaler_unregister_client(mock_journaler, 0);
+
+  librbd::journal::MirrorPeerClientMeta mirror_peer_client_meta;
+  librbd::util::s_image_id = "local image id";
+  mirror_peer_client_meta.image_id = "local image id";
+  mirror_peer_client_meta.state = librbd::journal::MIRROR_PEER_STATE_SYNCING;
+  librbd::journal::ClientData client_data;
+  client_data.client_meta = mirror_peer_client_meta;
+  expect_journaler_register_client(mock_journaler, client_data, 0);
+
+  // create the missing local image
+  MockCreateImageRequest mock_create_image_request;
+  expect_create_image(mock_create_image_request, "local image id", 0);
+
+  C_SaferCond ctx;
+  MockThreads mock_threads;
+  std::string local_image_id;
+  auto request = create_request(
+    mock_threads, mock_journaler, "global image id", "remote mirror uuid",
+    &mirror_peer_client_meta, &local_image_id, &ctx);
+  request->send();
+  ASSERT_EQ(0, ctx.wait());
+
+  ASSERT_EQ("local image id", local_image_id);
+  ASSERT_EQ("local image id", mirror_peer_client_meta.image_id);
+  ASSERT_EQ(librbd::journal::MIRROR_PEER_STATE_SYNCING,
+            mirror_peer_client_meta.state);
+}
+
+TEST_F(TestMockImageReplayerJournalCreateLocalImageRequest, UnregisterError) {
+  InSequence seq;
+
+  // re-register the client
+  ::journal::MockJournaler mock_journaler;
+  expect_journaler_unregister_client(mock_journaler, -EINVAL);
+
+  C_SaferCond ctx;
+  MockThreads mock_threads;
+  librbd::journal::MirrorPeerClientMeta mirror_peer_client_meta;
+  std::string local_image_id;
+  auto request = create_request(
+    mock_threads, mock_journaler, "global image id", "remote mirror uuid",
+    &mirror_peer_client_meta, &local_image_id, &ctx);
+  request->send();
+  ASSERT_EQ(-EINVAL, ctx.wait());
+}
+
+TEST_F(TestMockImageReplayerJournalCreateLocalImageRequest, RegisterError) {
+  InSequence seq;
+
+  // re-register the client
+  ::journal::MockJournaler mock_journaler;
+  expect_journaler_unregister_client(mock_journaler, 0);
+
+  librbd::journal::MirrorPeerClientMeta mirror_peer_client_meta;
+  librbd::util::s_image_id = "local image id";
+  mirror_peer_client_meta.image_id = "local image id";
+  mirror_peer_client_meta.state = librbd::journal::MIRROR_PEER_STATE_SYNCING;
+  librbd::journal::ClientData client_data;
+  client_data.client_meta = mirror_peer_client_meta;
+  expect_journaler_register_client(mock_journaler, client_data, -EINVAL);
+
+  C_SaferCond ctx;
+  MockThreads mock_threads;
+  std::string local_image_id;
+  auto request = create_request(
+    mock_threads, mock_journaler, "global image id", "remote mirror uuid",
+    &mirror_peer_client_meta, &local_image_id, &ctx);
+  request->send();
+  ASSERT_EQ(-EINVAL, ctx.wait());
+}
+
+TEST_F(TestMockImageReplayerJournalCreateLocalImageRequest, CreateImageError) {
+  InSequence seq;
+
+  // re-register the client
+  ::journal::MockJournaler mock_journaler;
+  expect_journaler_unregister_client(mock_journaler, 0);
+
+  librbd::journal::MirrorPeerClientMeta mirror_peer_client_meta;
+  librbd::util::s_image_id = "local image id";
+  mirror_peer_client_meta.image_id = "local image id";
+  mirror_peer_client_meta.state = librbd::journal::MIRROR_PEER_STATE_SYNCING;
+  librbd::journal::ClientData client_data;
+  client_data.client_meta = mirror_peer_client_meta;
+  expect_journaler_register_client(mock_journaler, client_data, 0);
+
+  // create the missing local image
+  MockCreateImageRequest mock_create_image_request;
+  expect_create_image(mock_create_image_request, "local image id", -EINVAL);
+
+  C_SaferCond ctx;
+  MockThreads mock_threads;
+  std::string local_image_id;
+  auto request = create_request(
+    mock_threads, mock_journaler, "global image id", "remote mirror uuid",
+    &mirror_peer_client_meta, &local_image_id, &ctx);
+  request->send();
+  ASSERT_EQ(-EINVAL, ctx.wait());
+}
+
+TEST_F(TestMockImageReplayerJournalCreateLocalImageRequest, CreateImageDuplicate) {
+  InSequence seq;
+
+  // re-register the client
+  ::journal::MockJournaler mock_journaler;
+  expect_journaler_unregister_client(mock_journaler, 0);
+
+  librbd::journal::MirrorPeerClientMeta mirror_peer_client_meta;
+  librbd::util::s_image_id = "local image id";
+  mirror_peer_client_meta.image_id = "local image id";
+  mirror_peer_client_meta.state = librbd::journal::MIRROR_PEER_STATE_SYNCING;
+  librbd::journal::ClientData client_data;
+  client_data.client_meta = mirror_peer_client_meta;
+  expect_journaler_register_client(mock_journaler, client_data, 0);
+
+  // create the missing local image
+  MockCreateImageRequest mock_create_image_request;
+  expect_create_image(mock_create_image_request, "local image id", -EBADF);
+
+  // update image id
+  expect_journaler_update_client(mock_journaler, client_data, 0);
+
+  // re-create the local image
+  expect_create_image(mock_create_image_request, "local image id", 0);
+
+  C_SaferCond ctx;
+  MockThreads mock_threads;
+  std::string local_image_id;
+  auto request = create_request(
+    mock_threads, mock_journaler, "global image id", "remote mirror uuid",
+    &mirror_peer_client_meta, &local_image_id, &ctx);
+  request->send();
+  ASSERT_EQ(0, ctx.wait());
+}
+
+TEST_F(TestMockImageReplayerJournalCreateLocalImageRequest, UpdateClientImageError) {
+  InSequence seq;
+
+  // re-register the client
+  ::journal::MockJournaler mock_journaler;
+  expect_journaler_unregister_client(mock_journaler, 0);
+
+  librbd::journal::MirrorPeerClientMeta mirror_peer_client_meta;
+  librbd::util::s_image_id = "local image id";
+  mirror_peer_client_meta.image_id = "local image id";
+  mirror_peer_client_meta.state = librbd::journal::MIRROR_PEER_STATE_SYNCING;
+  librbd::journal::ClientData client_data;
+  client_data.client_meta = mirror_peer_client_meta;
+  expect_journaler_register_client(mock_journaler, client_data, 0);
+
+  // create the missing local image
+  MockCreateImageRequest mock_create_image_request;
+  expect_create_image(mock_create_image_request, "local image id", -EBADF);
+
+  // update image id
+  expect_journaler_update_client(mock_journaler, client_data, -EINVAL);
+
+  C_SaferCond ctx;
+  MockThreads mock_threads;
+  std::string local_image_id;
+  auto request = create_request(
+    mock_threads, mock_journaler, "global image id", "remote mirror uuid",
+    &mirror_peer_client_meta, &local_image_id, &ctx);
+  request->send();
+  ASSERT_EQ(-EINVAL, ctx.wait());
+}
+
+} // namespace journal
+} // namespace image_replayer
+} // namespace mirror
+} // namespace rbd

src/tools/rbd_mirror/CMakeLists.txt

@@ -41,6 +41,7 @@ set(rbd_mirror_internal
   image_replayer/PrepareLocalImageRequest.cc
   image_replayer/PrepareRemoteImageRequest.cc
   image_replayer/Utils.cc
+  image_replayer/journal/CreateLocalImageRequest.cc
   image_replayer/journal/EventPreprocessor.cc
   image_replayer/journal/Replayer.cc
   image_replayer/journal/ReplayStatusFormatter.cc

src/tools/rbd_mirror/image_replayer/journal/CreateLocalImageRequest.cc

@@ -0,0 +1,194 @@
+// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
+// vim: ts=8 sw=2 smarttab
+
+#include "CreateLocalImageRequest.h"
+#include "include/rados/librados.hpp"
+#include "common/debug.h"
+#include "common/dout.h"
+#include "common/errno.h"
+#include "journal/Journaler.h"
+#include "librbd/ImageCtx.h"
+#include "librbd/Utils.h"
+#include "tools/rbd_mirror/ProgressContext.h"
+#include "tools/rbd_mirror/image_replayer/CreateImageRequest.h"
+
+#define dout_context g_ceph_context
+#define dout_subsys ceph_subsys_rbd_mirror
+#undef dout_prefix
+#define dout_prefix *_dout << "rbd::mirror::image_replayer::journal::" \
+                           << "CreateLocalImageRequest: " << this << " " \
+                           << __func__ << ": "
+
+namespace rbd {
+namespace mirror {
+namespace image_replayer {
+namespace journal {
+
+using librbd::util::create_context_callback;
+
+template <typename I>
+void CreateLocalImageRequest<I>::send() {
+  *m_local_image_id = "";
+  unregister_client();
+}
+
+template <typename I>
+void CreateLocalImageRequest<I>::unregister_client() {
+  dout(10) << dendl;
+  update_progress("UNREGISTER_CLIENT");
+
+  auto ctx = create_context_callback<
+    CreateLocalImageRequest<I>,
+    &CreateLocalImageRequest<I>::handle_unregister_client>(this);
+  m_remote_journaler->unregister_client(ctx);
+}
+
+template <typename I>
+void CreateLocalImageRequest<I>::handle_unregister_client(int r) {
+  dout(10) << "r=" << r << dendl;
+  if (r < 0 && r != -ENOENT) {
+    derr << "failed to unregister with remote journal: " << cpp_strerror(r)
+         << dendl;
+    finish(r);
+    return;
+  }
+
+  *m_client_meta = librbd::journal::MirrorPeerClientMeta{""};
+  register_client();
+}
+
+template <typename I>
+void CreateLocalImageRequest<I>::register_client() {
+  ceph_assert(m_local_image_id->empty());
+  *m_local_image_id = librbd::util::generate_image_id<I>(m_local_io_ctx);
+  dout(10) << "local_image_id=" << *m_local_image_id << dendl;
+  update_progress("REGISTER_CLIENT");
+
+  librbd::journal::MirrorPeerClientMeta client_meta{*m_local_image_id};
+  client_meta.state = librbd::journal::MIRROR_PEER_STATE_SYNCING;
+
+  librbd::journal::ClientData client_data{client_meta};
+  bufferlist client_data_bl;
+  encode(client_data, client_data_bl);
+
+  auto ctx = create_context_callback<
+    CreateLocalImageRequest<I>,
+    &CreateLocalImageRequest<I>::handle_register_client>(this);
+  m_remote_journaler->register_client(client_data_bl, ctx);
+}
+
+template <typename I>
+void CreateLocalImageRequest<I>::handle_register_client(int r) {
+  dout(10) << "r=" << r << dendl;
+
+  if (r < 0) {
+    derr << "failed to register with remote journal: " << cpp_strerror(r)
+         << dendl;
+    finish(r);
+    return;
+  }
+
+  *m_client_meta = librbd::journal::MirrorPeerClientMeta{*m_local_image_id};
+  m_client_meta->state = librbd::journal::MIRROR_PEER_STATE_SYNCING;
+
+  create_local_image();
+}
+
+template <typename I>
+void CreateLocalImageRequest<I>::create_local_image() {
+  dout(10) << "local_image_id=" << *m_local_image_id << dendl;
+  update_progress("CREATE_LOCAL_IMAGE");
+
+  m_remote_image_ctx->image_lock.lock_shared();
+  std::string image_name = m_remote_image_ctx->name;
+  m_remote_image_ctx->image_lock.unlock_shared();
+
+  auto ctx = create_context_callback<
+    CreateLocalImageRequest<I>,
+    &CreateLocalImageRequest<I>::handle_create_local_image>(this);
+  auto request = CreateImageRequest<I>::create(
+    m_threads, m_local_io_ctx, m_global_image_id, m_remote_mirror_uuid,
+    image_name, *m_local_image_id, m_remote_image_ctx, ctx);
+  request->send();
+}
+template <typename I>
+void CreateLocalImageRequest<I>::handle_create_local_image(int r) {
+  dout(10) << "r=" << r << dendl;
+
+  if (r == -EBADF) {
+    dout(5) << "image id " << *m_local_image_id << " already in-use" << dendl;
+    *m_local_image_id = "";
+    update_client_image();
+    return;
+  } else if (r < 0) {
+    if (r == -ENOENT) {
+      dout(10) << "parent image does not exist" << dendl;
+    } else {
+      derr << "failed to create local image: " << cpp_strerror(r) << dendl;
+    }
+    finish(r);
+    return;
+  }
+
+  finish(0);
+}
+
+template <typename I>
+void CreateLocalImageRequest<I>::update_client_image() {
+  ceph_assert(m_local_image_id->empty());
+  *m_local_image_id = librbd::util::generate_image_id<I>(m_local_io_ctx);
+
+  dout(10) << "local_image_id=" << *m_local_image_id << dendl;
+  update_progress("UPDATE_CLIENT_IMAGE");
+
+  librbd::journal::MirrorPeerClientMeta client_meta{*m_local_image_id};
+  client_meta.state = librbd::journal::MIRROR_PEER_STATE_SYNCING;
+
+  librbd::journal::ClientData client_data(client_meta);
+  bufferlist data_bl;
+  encode(client_data, data_bl);
+
+  auto ctx = create_context_callback<
+    CreateLocalImageRequest<I>,
+    &CreateLocalImageRequest<I>::handle_update_client_image>(this);
+  m_remote_journaler->update_client(data_bl, ctx);
+}
+
+template <typename I>
+void CreateLocalImageRequest<I>::handle_update_client_image(int r) {
+  dout(10) << "r=" << r << dendl;
+
+  if (r < 0) {
+    derr << "failed to update client: " << cpp_strerror(r) << dendl;
+    finish(r);
+    return;
+  }
+
+  *m_client_meta = librbd::journal::MirrorPeerClientMeta{*m_local_image_id};
+  m_client_meta->state = librbd::journal::MIRROR_PEER_STATE_SYNCING;
+  create_local_image();
+}
+
+template <typename I>
+void CreateLocalImageRequest<I>::finish(int r) {
+  dout(10) << "r=" << r << dendl;
+
+  m_on_finish->complete(r);
+  delete this;
+}
+
+template <typename I>
+void CreateLocalImageRequest<I>::update_progress(
+    const std::string& description) {
+  dout(15) << description << dendl;
+  if (m_progress_ctx != nullptr) {
+    m_progress_ctx->update_progress(description);
+  }
+}
+
+} // namespace journal
+} // namespace image_replayer
+} // namespace mirror
+} // namespace rbd
+
+template class rbd::mirror::image_replayer::journal::CreateLocalImageRequest<librbd::ImageCtx>;

src/tools/rbd_mirror/image_replayer/journal/CreateLocalImageRequest.h

@@ -0,0 +1,122 @@
+// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
+// vim: ts=8 sw=2 smarttab
+
+#ifndef RBD_MIRROR_IMAGE_REPLAYER_JOURNAL_CREATE_LOCAL_IMAGE_REQUEST_H
+#define RBD_MIRROR_IMAGE_REPLAYER_JOURNAL_CREATE_LOCAL_IMAGE_REQUEST_H
+
+#include "include/rados/librados_fwd.hpp"
+#include "librbd/journal/Types.h"
+#include "librbd/journal/TypeTraits.h"
+#include <string>
+
+struct Context;
+namespace librbd { class ImageCtx; }
+
+namespace rbd {
+namespace mirror {
+
+class ProgressContext;
+template <typename> struct Threads;
+
+namespace image_replayer {
+namespace journal {
+
+template <typename ImageCtxT>
+class CreateLocalImageRequest {
+public:
+  typedef librbd::journal::MirrorPeerClientMeta MirrorPeerClientMeta;
+  typedef librbd::journal::TypeTraits<ImageCtxT> TypeTraits;
+  typedef typename TypeTraits::Journaler Journaler;
+  typedef rbd::mirror::ProgressContext ProgressContext;
+
+  static CreateLocalImageRequest* create(
+      Threads<ImageCtxT>* threads, librados::IoCtx& local_io_ctx,
+      ImageCtxT* remote_image_ctx, Journaler* remote_journaler,
+      const std::string& global_image_id,
+      const std::string& remote_mirror_uuid,
+      MirrorPeerClientMeta* client_meta, ProgressContext* progress_ctx,
+      std::string* local_image_id, Context* on_finish) {
+    return new CreateLocalImageRequest(threads, local_io_ctx, remote_image_ctx,
+                                       remote_journaler, global_image_id,
+                                       remote_mirror_uuid, client_meta,
+                                       progress_ctx, local_image_id, on_finish);
+  }
+
+  CreateLocalImageRequest(
+      Threads<ImageCtxT>* threads, librados::IoCtx& local_io_ctx,
+      ImageCtxT* remote_image_ctx, Journaler* remote_journaler,
+      const std::string& global_image_id,
+      const std::string& remote_mirror_uuid,
+      MirrorPeerClientMeta* client_meta, ProgressContext* progress_ctx,
+      std::string* local_image_id, Context* on_finish)
+    : m_threads(threads), m_local_io_ctx(local_io_ctx),
+      m_remote_image_ctx(remote_image_ctx),
+      m_remote_journaler(remote_journaler),
+      m_global_image_id(global_image_id),
+      m_remote_mirror_uuid(remote_mirror_uuid), m_client_meta(client_meta),
+      m_progress_ctx(progress_ctx), m_local_image_id(local_image_id),
+      m_on_finish(on_finish) {
+  }
+
+  void send();
+
+private:
+  /**
+   * @verbatim
+   *
+   * <start>
+   *    |
+   *    v
+   * UNREGISTER_CLIENT
+   *    |
+   *    v
+   * REGISTER_CLIENT
+   *    |
+   *    |     . . . . . . . . . UPDATE_CLIENT_IMAGE
+   *    |     .                         ^
+   *    v     v         (id exists)     *
+   * CREATE_LOCAL_IMAGE * * * * * * * * *
+   *    |
+   *    v
+   * <finish>
+   *
+   * @endverbatim
+   */
+
+  Threads<ImageCtxT>* m_threads;
+  librados::IoCtx& m_local_io_ctx;
+  ImageCtxT* m_remote_image_ctx;
+  Journaler* m_remote_journaler;
+  std::string m_global_image_id;
+  std::string m_remote_mirror_uuid;
+  MirrorPeerClientMeta* m_client_meta;
+  ProgressContext* m_progress_ctx;
+  std::string* m_local_image_id;
+  Context* m_on_finish;
+
+  void unregister_client();
+  void handle_unregister_client(int r);
+
+  void register_client();
+  void handle_register_client(int r);
+
+  void create_local_image();
+  void handle_create_local_image(int r);
+
+  void update_client_image();
+  void handle_update_client_image(int r);
+
+  void finish(int r);
+
+  void update_progress(const std::string& description);
+
+};
+
+} // namespace journal
+} // namespace image_replayer
+} // namespace mirror
+} // namespace rbd
+
+extern template class rbd::mirror::image_replayer::journal::CreateLocalImageRequest<librbd::ImageCtx>;
+
+#endif // RBD_MIRROR_IMAGE_REPLAYER_JOURNAL_CREATE_LOCAL_IMAGE_REQUEST_H