From: Jason Dillaman <dillaman@redhat.com>
Date: Fri, 22 Feb 2019 15:59:26 +0000 (-0500)
Subject: rbd-mirror: complete pool watcher initialization if object missing
X-Git-Tag: v12.2.13~181^2~2
X-Git-Url: http://git-server-git.apps.pok.os.sepia.ceph.com/?a=commitdiff_plain;h=ff149e6121aa7b77a7be76d308a384d96ff3c6ba;p=ceph.git

rbd-mirror: complete pool watcher initialization if object missing

If the mirroring object is missing, complete the initialization and
continue to retry in the background. This is useful for cases where
the remote doesn't (yet) have mirroring enabled but the remote
pool watcher initialization is delaying the leader watcher promotion
to the point where the leader is blacklisted by its peers.

Signed-off-by: Jason Dillaman <dillaman@redhat.com>
(cherry picked from commit 80954cd914c86e11ffb6a8cbfcb21202cb8131b5)

Conflicts:
	src/tools/rbd_mirror/PoolReplayer.cc: missing handle_init_remote_pool_watcher
---

diff --git a/src/test/rbd_mirror/test_mock_PoolWatcher.cc b/src/test/rbd_mirror/test_mock_PoolWatcher.cc
index 4c7463d660c..3c241d8e7c3 100644
--- a/src/test/rbd_mirror/test_mock_PoolWatcher.cc
+++ b/src/test/rbd_mirror/test_mock_PoolWatcher.cc
@@ -498,7 +498,7 @@ TEST_F(TestMockPoolWatcher, RegisterWatcherMissing) {
                                     mock_listener);
   C_SaferCond ctx;
   mock_pool_watcher.init(&ctx);
-  ASSERT_EQ(0, ctx.wait());
+  ASSERT_EQ(-ENOENT, ctx.wait());
 
   ASSERT_TRUE(wait_for_update(1));
   expect_mirroring_watcher_unregister(mock_mirroring_watcher, 0);
diff --git a/src/tools/rbd_mirror/PoolReplayer.cc b/src/tools/rbd_mirror/PoolReplayer.cc
index c766e860903..1edd145b332 100644
--- a/src/tools/rbd_mirror/PoolReplayer.cc
+++ b/src/tools/rbd_mirror/PoolReplayer.cc
@@ -734,9 +734,29 @@ void PoolReplayer::init_remote_pool_watcher(Context *on_finish) {
   assert(!m_remote_pool_watcher);
   m_remote_pool_watcher.reset(new PoolWatcher<>(
     m_threads, m_remote_io_ctx, m_remote_pool_watcher_listener));
+  auto ctx = new FunctionContext([this, on_finish](int r) {
+      handle_init_remote_pool_watcher(r, on_finish);
+    });
   m_remote_pool_watcher->init(create_async_context_callback(
-    m_threads->work_queue, on_finish));
+    m_threads->work_queue, ctx));
+}
 
+void PoolReplayer::handle_init_remote_pool_watcher(int r, Context *on_finish) {
+  dout(10) << "r=" << r << dendl;
+  if (r == -ENOENT) {
+    // Technically nothing to do since the other side doesn't
+    // have mirroring enabled. Eventually the remote pool watcher will
+    // detect images (if mirroring is enabled), so no point propagating
+    // an error which would just busy-spin the state machines.
+    dout(0) << "remote peer does not have mirroring configured" << dendl;
+    r = 0;
+  } else if (r < 0) {
+    derr << "failed to retrieve remote images: " << cpp_strerror(r) << dendl;
+  }
+
+  on_finish->complete(r);
+
+  Mutex::Locker locker(m_lock);
   m_cond.Signal();
 }
 
diff --git a/src/tools/rbd_mirror/PoolReplayer.h b/src/tools/rbd_mirror/PoolReplayer.h
index 49aaee3c4ae..9a581756d5e 100644
--- a/src/tools/rbd_mirror/PoolReplayer.h
+++ b/src/tools/rbd_mirror/PoolReplayer.h
@@ -99,6 +99,7 @@ private:
   void handle_init_local_pool_watcher(int r, Context *on_finish);
 
   void init_remote_pool_watcher(Context *on_finish);
+  void handle_init_remote_pool_watcher(int r, Context *on_finish);
 
   void shut_down_pool_watchers(Context *on_finish);
   void handle_shut_down_pool_watchers(int r, Context *on_finish);
diff --git a/src/tools/rbd_mirror/PoolWatcher.cc b/src/tools/rbd_mirror/PoolWatcher.cc
index 8d60aa4f47a..316329e0967 100644
--- a/src/tools/rbd_mirror/PoolWatcher.cc
+++ b/src/tools/rbd_mirror/PoolWatcher.cc
@@ -174,6 +174,9 @@ void PoolWatcher<I>::handle_register_watcher(int r) {
   } else if (r == -ENOENT) {
     dout(5) << "mirroring directory does not exist" << dendl;
     schedule_refresh_images(30);
+
+    Mutex::Locker locker(m_lock);
+    std::swap(on_init_finish, m_on_init_finish);
   } else {
     derr << "unexpected error registering mirroring directory watch: "
          << cpp_strerror(r) << dendl;