From: Jason Dillaman <dillaman@redhat.com>
Date: Mon, 29 Apr 2019 14:13:21 +0000 (-0400)
Subject: librbd: simplify IO flush handling through AsyncOperation
X-Git-Tag: v13.2.7~277^2~1
X-Git-Url: http://git-server-git.apps.pok.os.sepia.ceph.com/?a=commitdiff_plain;h=69a03c2e042e87a16befdb6c278fe365659850c7;p=ceph.git

librbd: simplify IO flush handling through AsyncOperation

Allow ImageFlushRequest to directly execute a flush call through
AsyncOperation. This will allow the flush to be directly linked
to its preceeding IOs.

Signed-off-by: Jason Dillaman <dillaman@redhat.com>
(cherry picked from commit 09e4127d5df1e2a79f2536dc784ec3730feea9ce)

Conflicts:
	src/librbd/io/AsyncOperation.cc: trivial resolution
	src/test/librbd/io/test_mock_CopyupRequest.cc: DNE
---

diff --git a/src/librbd/ImageCtx.cc b/src/librbd/ImageCtx.cc
index ec09e64b55a..7755b940b35 100644
--- a/src/librbd/ImageCtx.cc
+++ b/src/librbd/ImageCtx.cc
@@ -661,25 +661,6 @@ public:
     return len;
   }
 
-  void ImageCtx::flush_async_operations() {
-    C_SaferCond ctx;
-    flush_async_operations(&ctx);
-    ctx.wait();
-  }
-
-  void ImageCtx::flush_async_operations(Context *on_finish) {
-    {
-      Mutex::Locker l(async_ops_lock);
-      if (!async_ops.empty()) {
-        ldout(cct, 20) << "flush async operations: " << on_finish << " "
-                       << "count=" << async_ops.size() << dendl;
-        async_ops.front()->add_flush_context(on_finish);
-        return;
-      }
-    }
-    on_finish->complete(0);
-  }
-
   void ImageCtx::cancel_async_requests() {
     C_SaferCond ctx;
     cancel_async_requests(&ctx);
diff --git a/src/librbd/ImageCtx.h b/src/librbd/ImageCtx.h
index 819eda609b9..7d55fb37d5d 100644
--- a/src/librbd/ImageCtx.h
+++ b/src/librbd/ImageCtx.h
@@ -292,9 +292,6 @@ namespace librbd {
     uint64_t prune_parent_extents(vector<pair<uint64_t,uint64_t> >& objectx,
 				  uint64_t overlap);
 
-    void flush_async_operations();
-    void flush_async_operations(Context *on_finish);
-
     void cancel_async_requests();
     void cancel_async_requests(Context *on_finish);
 
diff --git a/src/librbd/io/AsyncOperation.cc b/src/librbd/io/AsyncOperation.cc
index ca8daa4c098..efe9bd524cb 100644
--- a/src/librbd/io/AsyncOperation.cc
+++ b/src/librbd/io/AsyncOperation.cc
@@ -20,7 +20,8 @@ struct C_CompleteFlushes : public Context {
   ImageCtx *image_ctx;
   std::list<Context *> flush_contexts;
 
-  explicit C_CompleteFlushes(ImageCtx *image_ctx, std::list<Context *> &&flush_contexts)
+  explicit C_CompleteFlushes(ImageCtx *image_ctx,
+                             std::list<Context *> &&flush_contexts)
     : image_ctx(image_ctx), flush_contexts(std::move(flush_contexts)) {
   }
   void finish(int r) override {
@@ -73,11 +74,20 @@ void AsyncOperation::finish_op() {
   }
 }
 
-void AsyncOperation::add_flush_context(Context *on_finish) {
-  assert(m_image_ctx->async_ops_lock.is_locked());
-  ldout(m_image_ctx->cct, 20) << this << " " << __func__ << ": "
-                              << "flush=" << on_finish << dendl;
-  m_flush_contexts.push_back(on_finish);
+void AsyncOperation::flush(Context* on_finish) {
+  {
+    Mutex::Locker locker(m_image_ctx->async_ops_lock);
+    xlist<AsyncOperation *>::iterator iter(&m_xlist_item);
+    ++iter;
+
+    // linked list stored newest -> oldest ops
+    if (!iter.end()) {
+      (*iter)->m_flush_contexts.push_back(on_finish);
+      return;
+    }
+  }
+
+  m_image_ctx->op_work_queue->queue(on_finish);
 }
 
 } // namespace io
diff --git a/src/librbd/io/AsyncOperation.h b/src/librbd/io/AsyncOperation.h
index 5839a6964ba..74eb6724102 100644
--- a/src/librbd/io/AsyncOperation.h
+++ b/src/librbd/io/AsyncOperation.h
@@ -36,7 +36,7 @@ public:
   void start_op(ImageCtx &image_ctx);
   void finish_op();
 
-  void add_flush_context(Context *on_finish);
+  void flush(Context *on_finish);
 
 private:
 
diff --git a/src/librbd/io/ImageRequest.cc b/src/librbd/io/ImageRequest.cc
index 0b2aa121c8f..187b6d5b348 100644
--- a/src/librbd/io/ImageRequest.cc
+++ b/src/librbd/io/ImageRequest.cc
@@ -488,8 +488,8 @@ void ImageFlushRequest<I>::send_request() {
   }
 
   // ensure all in-flight IOs are settled if non-user flush request
-  image_ctx.flush_async_operations(ctx);
   aio_comp->start_op(true);
+  aio_comp->async_op.flush(ctx);
   aio_comp->put();
 
   // might be flushing during image shutdown
diff --git a/src/test/librbd/io/test_mock_ImageRequest.cc b/src/test/librbd/io/test_mock_ImageRequest.cc
index a785de2dbaa..ae0f201c5de 100644
--- a/src/test/librbd/io/test_mock_ImageRequest.cc
+++ b/src/test/librbd/io/test_mock_ImageRequest.cc
@@ -81,11 +81,6 @@ struct TestMockIoImageRequest : public TestMockFixture {
                   mock_image_ctx.image_ctx->op_work_queue->queue(&spec->dispatcher_ctx, r);
                 }));
   }
-
-  void expect_flush_async_operations(MockImageCtx &mock_image_ctx, int r) {
-    EXPECT_CALL(mock_image_ctx, flush_async_operations(_))
-      .WillOnce(CompleteContext(r, mock_image_ctx.image_ctx->op_work_queue));
-  }
 };
 
 TEST_F(TestMockIoImageRequest, AioWriteJournalAppendDisabled) {
@@ -159,7 +154,6 @@ TEST_F(TestMockIoImageRequest, AioFlushJournalAppendDisabled) {
 
   InSequence seq;
   expect_is_journal_appending(mock_journal, false);
-  expect_flush_async_operations(mock_image_ctx, 0);
   expect_object_request_send(mock_image_ctx, 0);
 
   C_SaferCond aio_comp_ctx;
diff --git a/src/test/librbd/mock/MockImageCtx.h b/src/test/librbd/mock/MockImageCtx.h
index 44ade806c75..3f9206cb784 100644
--- a/src/test/librbd/mock/MockImageCtx.h
+++ b/src/test/librbd/mock/MockImageCtx.h
@@ -186,7 +186,6 @@ struct MockImageCtx {
 			     librados::snap_t id));
 
   MOCK_METHOD0(user_flushed, void());
-  MOCK_METHOD1(flush_async_operations, void(Context *));
   MOCK_METHOD1(flush_copyup, void(Context *));
 
   MOCK_CONST_METHOD1(test_features, bool(uint64_t test_features));