1 files changed, 198 insertions, 0 deletions
diff --git a/src/librbd/mirror/DemoteRequest.cc b/src/librbd/mirror/DemoteRequest.cc
new file mode 100644
index 00000000..c5d38752
--- /dev/null
+++ b/src/librbd/mirror/DemoteRequest.cc
@@ -0,0 +1,198 @@
+// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
+// vim: ts=8 sw=2 smarttab
+
+#include "librbd/mirror/DemoteRequest.h"
+#include "common/dout.h"
+#include "common/errno.h"
+#include "cls/rbd/cls_rbd_client.h"
+#include "librbd/ExclusiveLock.h"
+#include "librbd/ImageCtx.h"
+#include "librbd/ImageState.h"
+#include "librbd/Journal.h"
+#include "librbd/Utils.h"
+#include "librbd/mirror/GetInfoRequest.h"
+
+#define dout_subsys ceph_subsys_rbd
+#undef dout_prefix
+#define dout_prefix *_dout << "librbd::mirror::DemoteRequest: " << this \
+                           << " " << __func__ << ": "
+
+namespace librbd {
+namespace mirror {
+
+using librbd::util::create_context_callback;
+
+template <typename I>
+void DemoteRequest<I>::send() {
+  get_info();
+}
+
+template <typename I>
+void DemoteRequest<I>::get_info() {
+  CephContext *cct = m_image_ctx.cct;
+  ldout(cct, 20) << dendl;
+
+  auto ctx = create_context_callback<
+    DemoteRequest<I>, &DemoteRequest<I>::handle_get_info>(this);
+  auto req = GetInfoRequest<I>::create(m_image_ctx, &m_mirror_image,
+                                       &m_promotion_state, ctx);
+  req->send();
+}
+
+template <typename I>
+void DemoteRequest<I>::handle_get_info(int r) {
+  CephContext *cct = m_image_ctx.cct;
+  ldout(cct, 20) << "r=" << r << dendl;
+
+  if (r < 0) {
+    lderr(cct) << "failed to retrieve mirroring state: " << cpp_strerror(r)
+               << dendl;
+    finish(r);
+    return;
+  } else if (m_mirror_image.state != cls::rbd::MIRROR_IMAGE_STATE_ENABLED) {
+    lderr(cct) << "mirroring is not currently enabled" << dendl;
+    finish(-EINVAL);
+    return;
+  } else if (m_promotion_state != PROMOTION_STATE_PRIMARY) {
+    lderr(cct) << "image is not primary" << dendl;
+    finish(-EINVAL);
+    return;
+  }
+
+  acquire_lock();
+}
+
+template <typename I>
+void DemoteRequest<I>::acquire_lock() {
+  CephContext *cct = m_image_ctx.cct;
+
+  m_image_ctx.owner_lock.get_read();
+  if (m_image_ctx.exclusive_lock == nullptr) {
+    m_image_ctx.owner_lock.put_read();
+    lderr(cct) << "exclusive lock is not active" << dendl;
+    finish(-EINVAL);
+    return;
+  }
+
+  // avoid accepting new requests from peers while we demote
+  // the image
+  m_image_ctx.exclusive_lock->block_requests(0);
+  m_blocked_requests = true;
+
+  if (m_image_ctx.exclusive_lock->is_lock_owner()) {
+    m_image_ctx.owner_lock.put_read();
+    demote();
+    return;
+  }
+
+  ldout(cct, 20) << dendl;
+
+  auto ctx = create_context_callback<
+    DemoteRequest<I>, &DemoteRequest<I>::handle_acquire_lock>(this);
+  m_image_ctx.exclusive_lock->acquire_lock(ctx);
+  m_image_ctx.owner_lock.put_read();
+}
+
+template <typename I>
+void DemoteRequest<I>::handle_acquire_lock(int r) {
+  CephContext *cct = m_image_ctx.cct;
+  ldout(cct, 20) << "r=" << r << dendl;
+
+  if (r < 0) {
+    lderr(cct) << "failed to lock image: " << cpp_strerror(r) << dendl;
+    finish(r);
+    return;
+  }
+
+  m_image_ctx.owner_lock.get_read();
+  if (m_image_ctx.exclusive_lock != nullptr &&
+      !m_image_ctx.exclusive_lock->is_lock_owner()) {
+    r = m_image_ctx.exclusive_lock->get_unlocked_op_error();
+    m_image_ctx.owner_lock.put_read();
+    lderr(cct) << "failed to acquire exclusive lock" << dendl;
+    finish(r);
+    return;
+  }
+  m_image_ctx.owner_lock.put_read();
+
+  demote();
+}
+
+template <typename I>
+void DemoteRequest<I>::demote() {
+  CephContext *cct = m_image_ctx.cct;
+  ldout(cct, 20) << dendl;
+
+  auto ctx = create_context_callback<
+    DemoteRequest<I>, &DemoteRequest<I>::handle_demote>(this);
+  Journal<I>::demote(&m_image_ctx, ctx);
+}
+
+template <typename I>
+void DemoteRequest<I>::handle_demote(int r) {
+  CephContext *cct = m_image_ctx.cct;
+  ldout(cct, 20) << "r=" << r << dendl;
+
+  if (r < 0) {
+    m_ret_val = r;
+    lderr(cct) << "failed to demote image: " << cpp_strerror(r) << dendl;
+  }
+
+  release_lock();
+}
+
+template <typename I>
+void DemoteRequest<I>::release_lock() {
+  CephContext *cct = m_image_ctx.cct;
+  ldout(cct, 20) << dendl;
+
+  m_image_ctx.owner_lock.get_read();
+  if (m_image_ctx.exclusive_lock == nullptr) {
+    m_image_ctx.owner_lock.put_read();
+    finish(0);
+    return;
+  }
+
+  auto ctx = create_context_callback<
+    DemoteRequest<I>, &DemoteRequest<I>::handle_release_lock>(this);
+  m_image_ctx.exclusive_lock->release_lock(ctx);
+  m_image_ctx.owner_lock.put_read();
+}
+
+template <typename I>
+void DemoteRequest<I>::handle_release_lock(int r) {
+  CephContext *cct = m_image_ctx.cct;
+  ldout(cct, 20) << "r=" << r << dendl;
+
+  if (r < 0) {
+    lderr(cct) << "failed to release exclusive lock: " << cpp_strerror(r)
+               << dendl;
+  }
+
+  finish(r);
+}
+
+template <typename I>
+void DemoteRequest<I>::finish(int r) {
+  if (m_ret_val < 0) {
+    r = m_ret_val;
+  }
+
+  {
+    RWLock::RLocker owner_locker(m_image_ctx.owner_lock);
+    if (m_blocked_requests && m_image_ctx.exclusive_lock != nullptr) {
+      m_image_ctx.exclusive_lock->unblock_requests();
+    }
+  }
+
+  CephContext *cct = m_image_ctx.cct;
+  ldout(cct, 20) << "r=" << r << dendl;
+
+  m_on_finish->complete(r);
+  delete this;
+}
+
+} // namespace mirror
+} // namespace librbd
+
+template class librbd::mirror::DemoteRequest<librbd::ImageCtx>;