From 867c7f67c5f80905d46f4e6f2e6c30cb6a20c88c Mon Sep 17 00:00:00 2001
From: Jason Dillaman <dillaman@redhat.com>
Date: Wed, 19 Feb 2020 19:03:40 -0500
Subject: [PATCH] rbd-mirror: periodically update sync position for
 snapshot-based images

This will allow the sync to restart at the last known successfully copied
object.

Signed-off-by: Jason Dillaman <dillaman@redhat.com>
---
 .../image_replayer/snapshot/Replayer.cc       | 47 ++++++++++++++-----
 .../image_replayer/snapshot/Replayer.h        |  4 +-
 2 files changed, 39 insertions(+), 12 deletions(-)

diff --git a/src/tools/rbd_mirror/image_replayer/snapshot/Replayer.cc b/src/tools/rbd_mirror/image_replayer/snapshot/Replayer.cc
index 095e2ca2e933..1516713b2cfc 100644
--- a/src/tools/rbd_mirror/image_replayer/snapshot/Replayer.cc
+++ b/src/tools/rbd_mirror/image_replayer/snapshot/Replayer.cc
@@ -76,8 +76,8 @@ struct Replayer<I>::ProgressContext : public librbd::ProgressContext {
   ProgressContext(Replayer* replayer) : replayer(replayer) {
   }
 
-  int update_progress(uint64_t offset, uint64_t total) override {
-    replayer->handle_copy_image_progress(offset, total);
+  int update_progress(uint64_t object_number, uint64_t object_count) override {
+    replayer->handle_copy_image_progress(object_number, object_count);
     return 0;
   }
 };
@@ -631,10 +631,15 @@ void Replayer<I>::handle_copy_image(int r) {
 }
 
 template <typename I>
-void Replayer<I>::handle_copy_image_progress(uint64_t offset, uint64_t total) {
-  dout(10) << "offset=" << offset << ", total=" << total << dendl;
+void Replayer<I>::handle_copy_image_progress(uint64_t object_number,
+                                             uint64_t object_count) {
+  dout(10) << "object_number=" << object_number << ", "
+           << "object_count=" << object_count << dendl;
 
-  // TODO
+  std::unique_lock locker{m_lock};
+  m_local_mirror_snap_ns.last_copied_object_number = object_number;
+
+  update_non_primary_snapshot(false);
 }
 
 template <typename I>
@@ -663,25 +668,33 @@ void Replayer<I>::handle_apply_image_state(int r) {
     return;
   }
 
+  std::unique_lock locker{m_lock};
   update_non_primary_snapshot(true);
 }
 
 template <typename I>
 void Replayer<I>::update_non_primary_snapshot(bool complete) {
-  dout(10) << dendl;
-
-  if (complete) {
+  ceph_assert(ceph_mutex_is_locked_by_me(m_lock));
+  if (!complete) {
+    // disallow two in-flight updates if this isn't the completion of the sync
+    if (m_updating_sync_point) {
+      return;
+    }
+    m_updating_sync_point = true;
+  } else {
     m_local_mirror_snap_ns.complete = true;
   }
 
+  dout(10) << dendl;
+
   librados::ObjectWriteOperation op;
   librbd::cls_client::mirror_image_snapshot_set_copy_progress(
     &op, m_local_snap_id_end, m_local_mirror_snap_ns.complete,
     m_local_mirror_snap_ns.last_copied_object_number);
 
-  auto ctx = new LambdaContext([this, complete](int r) {
+  auto ctx = new C_TrackedOp(this, new LambdaContext([this, complete](int r) {
       handle_update_non_primary_snapshot(complete, r);
-    });
+    }));
   auto aio_comp = create_rados_callback(ctx);
   int r = m_state_builder->local_image_ctx->md_ctx.aio_operate(
     m_state_builder->local_image_ctx->header_oid, aio_comp, &op);
@@ -696,7 +709,19 @@ void Replayer<I>::handle_update_non_primary_snapshot(bool complete, int r) {
   if (r < 0) {
     derr << "failed to update local snapshot progress: " << cpp_strerror(r)
          << dendl;
-    handle_replay_complete(r, "failed to update local snapshot progress");
+    if (complete) {
+      // only fail if this was the final update
+      handle_replay_complete(r, "failed to update local snapshot progress");
+      return;
+    }
+  }
+
+  if (!complete) {
+    // periodic sync-point update -- do not advance state machine
+    std::unique_lock locker{m_lock};
+
+    ceph_assert(m_updating_sync_point);
+    m_updating_sync_point = false;
     return;
   }
 
diff --git a/src/tools/rbd_mirror/image_replayer/snapshot/Replayer.h b/src/tools/rbd_mirror/image_replayer/snapshot/Replayer.h
index f8faf657ee8f..4fb7e90aed59 100644
--- a/src/tools/rbd_mirror/image_replayer/snapshot/Replayer.h
+++ b/src/tools/rbd_mirror/image_replayer/snapshot/Replayer.h
@@ -204,6 +204,7 @@ private:
   ProgressContext* m_progress_ctx = nullptr;
 
   bool m_remote_image_updated = false;
+  bool m_updating_sync_point = false;
 
   void refresh_local_image();
   void handle_refresh_local_image(int r);
@@ -228,7 +229,8 @@ private:
 
   void copy_image();
   void handle_copy_image(int r);
-  void handle_copy_image_progress(uint64_t offset, uint64_t total);
+  void handle_copy_image_progress(uint64_t object_number,
+                                  uint64_t object_count);
 
   void apply_image_state();
   void handle_apply_image_state(int r);
-- 
2.47.3