From 0a8a6126ea35344e85af7eb64ffc490938edba51 Mon Sep 17 00:00:00 2001
From: Jason Dillaman <dillaman@redhat.com>
Date: Mon, 16 May 2016 18:08:35 -0400
Subject: [PATCH] journal: helper method to detect newer tags

Signed-off-by: Jason Dillaman <dillaman@redhat.com>
---
 src/journal/JournalMetadata.cc           | 70 ++++++++++++++++++++++++
 src/journal/JournalMetadata.h            |  2 +
 src/test/journal/test_JournalMetadata.cc | 29 ++++++++++
 3 files changed, 101 insertions(+)

diff --git a/src/journal/JournalMetadata.cc b/src/journal/JournalMetadata.cc
index a05aa5a907ce0..c24a96aa0ef2b 100644
--- a/src/journal/JournalMetadata.cc
+++ b/src/journal/JournalMetadata.cc
@@ -336,6 +336,66 @@ struct C_FlushCommitPosition : public Context {
   }
 };
 
+struct C_AssertActiveTag : public Context {
+  CephContext *cct;
+  librados::IoCtx &ioctx;
+  const std::string &oid;
+  AsyncOpTracker &async_op_tracker;
+  std::string client_id;
+  uint64_t tag_tid;
+  Context *on_finish;
+
+  bufferlist out_bl;
+
+  C_AssertActiveTag(CephContext *cct, librados::IoCtx &ioctx,
+                    const std::string &oid, AsyncOpTracker &async_op_tracker,
+                    const std::string &client_id, uint64_t tag_tid,
+                    Context *on_finish)
+    : cct(cct), ioctx(ioctx), oid(oid), async_op_tracker(async_op_tracker),
+      client_id(client_id), tag_tid(tag_tid), on_finish(on_finish) {
+    async_op_tracker.start_op();
+  }
+  virtual ~C_AssertActiveTag() {
+    async_op_tracker.finish_op();
+  }
+
+  void send() {
+    ldout(cct, 20) << "C_AssertActiveTag: " << __func__ << dendl;
+
+    librados::ObjectReadOperation op;
+    client::tag_list_start(&op, tag_tid, 2, client_id, boost::none);
+
+    librados::AioCompletion *comp = librados::Rados::aio_create_completion(
+      this, nullptr, &utils::rados_state_callback<
+        C_AssertActiveTag, &C_AssertActiveTag::handle_send>);
+
+    int r = ioctx.aio_operate(oid, comp, &op, &out_bl);
+    assert(r == 0);
+    comp->release();
+  }
+
+  void handle_send(int r) {
+    ldout(cct, 20) << "C_AssertActiveTag: " << __func__ << ": r=" << r << dendl;
+
+    std::set<cls::journal::Tag> tags;
+    if (r == 0) {
+      bufferlist::iterator it = out_bl.begin();
+      r = client::tag_list_finish(&it, &tags);
+    }
+
+    // NOTE: since 0 is treated as an uninitialized list filter, we need to
+    // load to entries and look at the last tid
+    if (r == 0 && !tags.empty() && tags.rbegin()->tid > tag_tid) {
+      r = -ESTALE;
+    }
+    complete(r);
+  }
+
+  virtual void finish(int r) {
+    on_finish->complete(r);
+  }
+};
+
 } // anonymous namespace
 
 JournalMetadata::JournalMetadata(ContextWQ *work_queue, SafeTimer *timer,
@@ -564,6 +624,16 @@ void JournalMetadata::set_active_set(uint64_t object_set, Context *on_finish) {
   m_active_set = object_set;
 }
 
+void JournalMetadata::assert_active_tag(uint64_t tag_tid, Context *on_finish) {
+  Mutex::Locker locker(m_lock);
+
+  C_AssertActiveTag *ctx = new C_AssertActiveTag(m_cct, m_ioctx, m_oid,
+                                                 m_async_op_tracker,
+                                                 m_client_id, tag_tid,
+                                                 on_finish);
+  ctx->send();
+}
+
 void JournalMetadata::flush_commit_position() {
   ldout(m_cct, 20) << __func__ << dendl;
 
diff --git a/src/journal/JournalMetadata.h b/src/journal/JournalMetadata.h
index 9d19af69f1032..db30cf15951a3 100644
--- a/src/journal/JournalMetadata.h
+++ b/src/journal/JournalMetadata.h
@@ -117,6 +117,8 @@ public:
     return m_active_set;
   }
 
+  void assert_active_tag(uint64_t tag_tid, Context *on_finish);
+
   void flush_commit_position();
   void flush_commit_position(Context *on_safe);
   void get_commit_position(ObjectSetPosition *commit_position) const {
diff --git a/src/test/journal/test_JournalMetadata.cc b/src/test/journal/test_JournalMetadata.cc
index b0bb41c844c99..b8f559365f811 100644
--- a/src/test/journal/test_JournalMetadata.cc
+++ b/src/test/journal/test_JournalMetadata.cc
@@ -115,3 +115,32 @@ TEST_F(TestJournalMetadata, UpdateActiveObject) {
 
   ASSERT_EQ(123U, metadata1->get_active_set());
 }
+
+TEST_F(TestJournalMetadata, AssertActiveTag) {
+  std::string oid = get_temp_oid();
+
+  ASSERT_EQ(0, create(oid));
+  ASSERT_EQ(0, client_register(oid, "client1", ""));
+
+  journal::JournalMetadataPtr metadata = create_metadata(oid, "client1");
+  ASSERT_EQ(0, init_metadata(metadata));
+  ASSERT_TRUE(wait_for_update(metadata));
+
+  C_SaferCond ctx1;
+  cls::journal::Tag tag1;
+  metadata->allocate_tag(cls::journal::Tag::TAG_CLASS_NEW, {}, &tag1, &ctx1);
+  ASSERT_EQ(0, ctx1.wait());
+
+  C_SaferCond ctx2;
+  metadata->assert_active_tag(tag1.tid, &ctx2);
+  ASSERT_EQ(0, ctx2.wait());
+
+  C_SaferCond ctx3;
+  cls::journal::Tag tag2;
+  metadata->allocate_tag(tag1.tag_class, {}, &tag2, &ctx3);
+  ASSERT_EQ(0, ctx3.wait());
+
+  C_SaferCond ctx4;
+  metadata->assert_active_tag(tag1.tid, &ctx4);
+  ASSERT_EQ(-ESTALE, ctx4.wait());
+}
-- 
2.39.5