librbd: helper state machine for detaching children for v1/v2 clones

Signed-off-by: Jason Dillaman <dillaman@redhat.com>

src/librbd/CMakeLists.txt

@@ -46,6 +46,7 @@ set(librbd_internal_srcs
   image/CloneRequest.cc
   image/CloseRequest.cc
   image/CreateRequest.cc
+  image/DetachChildRequest.cc
   image/OpenRequest.cc
   image/RefreshParentRequest.cc
   image/RefreshRequest.cc

src/librbd/image/DetachChildRequest.cc

@@ -0,0 +1,136 @@
+// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
+// vim: ts=8 sw=2 smarttab
+
+#include "librbd/image/DetachChildRequest.h"
+#include "common/dout.h"
+#include "common/errno.h"
+#include "common/WorkQueue.h"
+#include "cls/rbd/cls_rbd_client.h"
+#include "librbd/ImageCtx.h"
+#include "librbd/Utils.h"
+#include <string>
+
+#define dout_subsys ceph_subsys_rbd
+#undef dout_prefix
+#define dout_prefix *_dout << "librbd::image::DetachChildRequest: " << this \
+                           << " " << __func__ << ": "
+
+namespace librbd {
+namespace image {
+
+using util::create_context_callback;
+using util::create_rados_callback;
+
+template <typename I>
+void DetachChildRequest<I>::send() {
+  {
+    RWLock::RLocker snap_locker(m_image_ctx.snap_lock);
+    RWLock::RLocker parent_locker(m_image_ctx.parent_lock);
+
+    // use oldest snapshot or HEAD for parent spec
+    if (!m_image_ctx.snap_info.empty()) {
+      m_parent_spec = m_image_ctx.snap_info.begin()->second.parent.spec;
+    } else {
+      m_parent_spec = m_image_ctx.parent_md.spec;
+    }
+  }
+
+  if (m_parent_spec.pool_id == -1) {
+    // ignore potential race with parent disappearing
+    m_image_ctx.op_work_queue->queue(create_context_callback<
+      DetachChildRequest<I>,
+      &DetachChildRequest<I>::finish>(this), 0);
+    return;
+  } else if (!m_image_ctx.test_op_features(RBD_OPERATION_FEATURE_CLONE_CHILD)) {
+    clone_v1_remove_child();
+    return;
+  }
+
+  clone_v2_child_detach();
+}
+
+template <typename I>
+void DetachChildRequest<I>::clone_v2_child_detach() {
+  auto cct = m_image_ctx.cct;
+  ldout(cct, 5) << dendl;
+
+  librados::ObjectWriteOperation op;
+  cls_client::child_detach(&op, m_parent_spec.snap_id,
+                           {m_image_ctx.md_ctx.get_id(), m_image_ctx.id});
+
+  librados::Rados rados(m_image_ctx.md_ctx);
+  int r = rados.ioctx_create2(m_parent_spec.pool_id, m_parent_io_ctx);
+  assert(r == 0);
+
+  auto aio_comp = create_rados_callback<
+    DetachChildRequest<I>,
+    &DetachChildRequest<I>::handle_clone_v2_child_detach>(this);
+  r = m_parent_io_ctx.aio_operate(util::header_name(m_parent_spec.image_id),
+                                  aio_comp, &op);
+  assert(r == 0);
+  aio_comp->release();
+}
+
+template <typename I>
+void DetachChildRequest<I>::handle_clone_v2_child_detach(int r) {
+  auto cct = m_image_ctx.cct;
+  ldout(cct, 5) << "r=" << r << dendl;
+
+  if (r == -ENOENT) {
+    r = 0;
+  } else if (r < 0) {
+    lderr(cct) << "error detaching child from parent: " << cpp_strerror(r)
+               << dendl;
+    finish(r);
+    return;
+  }
+
+  finish(0);
+}
+
+template<typename I>
+void DetachChildRequest<I>::clone_v1_remove_child() {
+  auto cct = m_image_ctx.cct;
+  ldout(cct, 5) << dendl;
+
+  librados::ObjectWriteOperation op;
+  librbd::cls_client::remove_child(&op, m_parent_spec, m_image_ctx.id);
+
+  auto aio_comp = create_rados_callback<
+    DetachChildRequest<I>,
+    &DetachChildRequest<I>::handle_clone_v1_remove_child>(this);
+  int r = m_image_ctx.md_ctx.aio_operate(RBD_CHILDREN, aio_comp, &op);
+  assert(r == 0);
+  aio_comp->release();
+}
+
+template<typename I>
+void DetachChildRequest<I>::handle_clone_v1_remove_child(int r) {
+  auto cct = m_image_ctx.cct;
+  ldout(cct, 5) << "r=" << r << dendl;
+
+  if (r == -ENOENT) {
+    r = 0;
+  } else if (r < 0) {
+    lderr(cct) << "failed to remove child from children list: "
+               << cpp_strerror(r) << dendl;
+    finish(r);
+    return;
+  }
+
+  finish(0);
+}
+
+template <typename I>
+void DetachChildRequest<I>::finish(int r) {
+  auto cct = m_image_ctx.cct;
+  ldout(cct, 5) << "r=" << r << dendl;
+
+  m_on_finish->complete(r);
+  delete this;
+}
+
+} // namespace image
+} // namespace librbd
+
+template class librbd::image::DetachChildRequest<librbd::ImageCtx>;

src/librbd/image/DetachChildRequest.h

@@ -0,0 +1,74 @@
+// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
+// vim: ts=8 sw=2 smarttab
+
+#ifndef CEPH_LIBRBD_IMAGE_DETACH_CHILD_REQUEST_H
+#define CEPH_LIBRBD_IMAGE_DETACH_CHILD_REQUEST_H
+
+#include "include/int_types.h"
+#include "include/buffer.h"
+#include "include/rados/librados.hpp"
+#include "librbd/Types.h"
+
+class Context;
+
+namespace librbd {
+
+class ImageCtx;
+
+namespace image {
+
+template <typename ImageCtxT = ImageCtx>
+class DetachChildRequest {
+public:
+  static DetachChildRequest* create(ImageCtxT& image_ctx, Context* on_finish) {
+    return new DetachChildRequest(image_ctx, on_finish);
+  }
+
+  DetachChildRequest(ImageCtxT& image_ctx, Context* on_finish)
+    : m_image_ctx(image_ctx), m_on_finish(on_finish) {
+  }
+
+  void send();
+
+private:
+  /**
+   * @verbatim
+   *
+   * <start>
+   *    |
+   *    v (skip if v1)
+   * CHILD_DETACH
+   *    |
+   *    v (skip if v2)
+   * REMOVE_CHILD
+   *    |
+   *    v
+   * <finish>
+   *
+   * @endverbatim
+   */
+
+  ImageCtxT& m_image_ctx;
+  Context* m_on_finish;
+
+  librados::IoCtx m_parent_io_ctx;
+  ParentSpec m_parent_spec;
+
+  ceph::bufferlist m_out_bl;
+
+  void clone_v2_child_detach();
+  void handle_clone_v2_child_detach(int r);
+
+  void clone_v1_remove_child();
+  void handle_clone_v1_remove_child(int r);
+
+  void finish(int r);
+
+};
+
+} // namespace image
+} // namespace librbd
+
+extern template class librbd::image::DetachChildRequest<librbd::ImageCtx>;
+
+#endif // CEPH_LIBRBD_IMAGE_DETACH_CHILD_REQUEST_H

src/test/librbd/CMakeLists.txt

@@ -44,6 +44,7 @@ set(unittest_librbd_srcs
   exclusive_lock/test_mock_PostAcquireRequest.cc
   exclusive_lock/test_mock_PreReleaseRequest.cc
   image/test_mock_CloneRequest.cc
+  image/test_mock_DetachChildRequest.cc
   image/test_mock_RefreshRequest.cc
   image/test_mock_RemoveRequest.cc
   io/test_mock_ImageRequest.cc

src/test/librbd/image/test_mock_DetachChildRequest.cc

@@ -0,0 +1,160 @@
+// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
+// vim: ts=8 sw=2 smarttab
+
+#include "test/librbd/test_mock_fixture.h"
+#include "test/librbd/test_support.h"
+#include "test/librbd/mock/MockImageCtx.h"
+#include "test/librbd/mock/MockContextWQ.h"
+#include "test/librados_test_stub/MockTestMemIoCtxImpl.h"
+#include "test/librados_test_stub/MockTestMemRadosClient.h"
+#include "librbd/image/DetachChildRequest.h"
+#include "gmock/gmock.h"
+#include "gtest/gtest.h"
+
+namespace librbd {
+namespace {
+
+struct MockTestImageCtx : public MockImageCtx {
+  MockTestImageCtx(ImageCtx &image_ctx) : MockImageCtx(image_ctx) {
+  }
+};
+
+} // anonymous namespace
+} // namespace librbd
+
+// template definitions
+#include "librbd/image/DetachChildRequest.cc"
+
+namespace librbd {
+namespace image {
+
+using ::testing::_;
+using ::testing::DoAll;
+using ::testing::InSequence;
+using ::testing::Return;
+using ::testing::StrEq;
+
+class TestMockImageDetachChildRequest : public TestMockFixture {
+public:
+  typedef DetachChildRequest<MockTestImageCtx> MockDetachChildRequest;
+
+  void SetUp() override {
+    TestMockFixture::SetUp();
+
+    ASSERT_EQ(0, open_image(m_image_name, &image_ctx));
+  }
+
+  void expect_test_op_features(MockTestImageCtx& mock_image_ctx, bool enabled) {
+    EXPECT_CALL(mock_image_ctx,
+                test_op_features(RBD_OPERATION_FEATURE_CLONE_CHILD))
+      .WillOnce(Return(enabled));
+  }
+
+  void expect_child_detach(MockImageCtx &mock_image_ctx, int r) {
+    auto& parent_spec = mock_image_ctx.parent_md.spec;
+
+    bufferlist bl;
+    encode(parent_spec.snap_id, bl);
+    encode(cls::rbd::ChildImageSpec{mock_image_ctx.md_ctx.get_id(),
+                                    mock_image_ctx.id}, bl);
+
+    auto& io_ctx_impl = get_mock_io_ctx(mock_image_ctx.md_ctx);
+    auto rados_client = io_ctx_impl.get_mock_rados_client();
+
+    EXPECT_CALL(*rados_client, create_ioctx(_, _))
+      .WillOnce(DoAll(GetReference(&io_ctx_impl),
+                      Return(&io_ctx_impl)));
+
+    EXPECT_CALL(io_ctx_impl,
+                exec(util::header_name(parent_spec.image_id),
+                     _, StrEq("rbd"), StrEq("child_detach"), ContentsEqual(bl),
+                     _, _))
+      .WillOnce(Return(r));
+  }
+
+  void expect_remove_child(MockImageCtx &mock_image_ctx, int r) {
+    EXPECT_CALL(get_mock_io_ctx(mock_image_ctx.md_ctx),
+                exec(RBD_CHILDREN, _, StrEq("rbd"), StrEq("remove_child"), _,
+                     _, _))
+      .WillOnce(Return(r));
+  }
+
+  librbd::ImageCtx *image_ctx;
+};
+
+TEST_F(TestMockImageDetachChildRequest, SuccessV1) {
+  REQUIRE_FEATURE(RBD_FEATURE_LAYERING);
+
+  MockTestImageCtx mock_image_ctx(*image_ctx);
+  mock_image_ctx.parent_md.spec = {m_ioctx.get_id(), "parent id", 234};
+
+  InSequence seq;
+  expect_test_op_features(mock_image_ctx, false);
+  expect_remove_child(mock_image_ctx, 0);
+
+  C_SaferCond ctx;
+  auto req = MockDetachChildRequest::create(mock_image_ctx, &ctx);
+  req->send();
+  ASSERT_EQ(0, ctx.wait());
+}
+
+TEST_F(TestMockImageDetachChildRequest, SuccessV2) {
+  REQUIRE_FEATURE(RBD_FEATURE_LAYERING);
+
+  MockTestImageCtx mock_image_ctx(*image_ctx);
+  mock_image_ctx.parent_md.spec = {m_ioctx.get_id(), "parent id", 234};
+
+  InSequence seq;
+  expect_test_op_features(mock_image_ctx, true);
+  expect_child_detach(mock_image_ctx, 0);
+
+  C_SaferCond ctx;
+  auto req = MockDetachChildRequest::create(mock_image_ctx, &ctx);
+  req->send();
+  ASSERT_EQ(0, ctx.wait());
+}
+
+TEST_F(TestMockImageDetachChildRequest, ParentDNE) {
+  MockTestImageCtx mock_image_ctx(*image_ctx);
+  expect_op_work_queue(mock_image_ctx);
+
+  C_SaferCond ctx;
+  auto req = MockDetachChildRequest::create(mock_image_ctx, &ctx);
+  req->send();
+  ASSERT_EQ(0, ctx.wait());
+}
+
+TEST_F(TestMockImageDetachChildRequest, ChildDetachError) {
+  REQUIRE_FEATURE(RBD_FEATURE_LAYERING);
+
+  MockTestImageCtx mock_image_ctx(*image_ctx);
+  mock_image_ctx.parent_md.spec = {m_ioctx.get_id(), "parent id", 234};
+
+  InSequence seq;
+  expect_test_op_features(mock_image_ctx, true);
+  expect_child_detach(mock_image_ctx, -EPERM);
+
+  C_SaferCond ctx;
+  auto req = MockDetachChildRequest::create(mock_image_ctx, &ctx);
+  req->send();
+  ASSERT_EQ(-EPERM, ctx.wait());
+}
+
+TEST_F(TestMockImageDetachChildRequest, RemoveChildError) {
+  REQUIRE_FEATURE(RBD_FEATURE_LAYERING);
+
+  MockTestImageCtx mock_image_ctx(*image_ctx);
+  mock_image_ctx.parent_md.spec = {m_ioctx.get_id(), "parent id", 234};
+
+  InSequence seq;
+  expect_test_op_features(mock_image_ctx, false);
+  expect_remove_child(mock_image_ctx, -EINVAL);
+
+  C_SaferCond ctx;
+  auto req = MockDetachChildRequest::create(mock_image_ctx, &ctx);
+  req->send();
+  ASSERT_EQ(-EINVAL, ctx.wait());
+}
+
+} // namespace image
+} // namespace librbd

src/test/librbd/mock/MockImageCtx.h

@@ -198,6 +198,8 @@ struct MockImageCtx {
   MOCK_CONST_METHOD2(test_features, bool(uint64_t test_features,
                                          const RWLock &in_snap_lock));
 
+  MOCK_CONST_METHOD1(test_op_features, bool(uint64_t op_features));
+
   MOCK_METHOD1(cancel_async_requests, void(Context*));
 
   MOCK_METHOD0(create_exclusive_lock, MockExclusiveLock*());