Adding upstream version 16.2.11+ds.upstream/16.2.11+dsupstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1789 insertions, 0 deletions

diff --git a/src/test/librbd/test_internal.cc b/src/test/librbd/test_internal.cc
new file mode 100644
index 000000000..4a793a021
--- /dev/null
+++ b/src/test/librbd/test_internal.cc
@@ -0,0 +1,1789 @@
+// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
+// vim: ts=8 sw=2 smarttab
+
+#include "cls/journal/cls_journal_client.h"
+#include "cls/rbd/cls_rbd_client.h"
+#include "cls/rbd/cls_rbd_types.h"
+#include "test/librbd/test_fixture.h"
+#include "test/librbd/test_support.h"
+#include "include/rbd/librbd.h"
+#include "librbd/ExclusiveLock.h"
+#include "librbd/ImageState.h"
+#include "librbd/ImageWatcher.h"
+#include "librbd/internal.h"
+#include "librbd/ObjectMap.h"
+#include "librbd/Operations.h"
+#include "librbd/api/DiffIterate.h"
+#include "librbd/api/Image.h"
+#include "librbd/api/Io.h"
+#include "librbd/api/Migration.h"
+#include "librbd/api/PoolMetadata.h"
+#include "librbd/api/Snapshot.h"
+#include "librbd/io/AioCompletion.h"
+#include "librbd/io/ImageRequest.h"
+#include "osdc/Striper.h"
+#include "common/Cond.h"
+#include <boost/scope_exit.hpp>
+#include <boost/algorithm/string/predicate.hpp>
+#include <boost/assign/list_of.hpp>
+#include <utility>
+#include <vector>
+
+void register_test_internal() {
+}
+
+namespace librbd {
+
+class TestInternal : public TestFixture {
+public:
+
+  TestInternal() {}
+
+  typedef std::vector<std::pair<std::string, bool> > Snaps;
+
+  void TearDown() override {
+    unlock_image();
+    for (Snaps::iterator iter = m_snaps.begin(); iter != m_snaps.end(); ++iter) {
+      librbd::ImageCtx *ictx;
+      EXPECT_EQ(0, open_image(m_image_name, &ictx));
+      if (iter->second) {
+	EXPECT_EQ(0,
+		  ictx->operations->snap_unprotect(cls::rbd::UserSnapshotNamespace(),
+						   iter->first.c_str()));
+      }
+      EXPECT_EQ(0,
+		ictx->operations->snap_remove(cls::rbd::UserSnapshotNamespace(),
+					      iter->first.c_str()));
+    }
+
+    TestFixture::TearDown();
+  }
+
+  int create_snapshot(const char *snap_name, bool snap_protect) {
+    librbd::ImageCtx *ictx;
+    int r = open_image(m_image_name, &ictx);
+    if (r < 0) {
+      return r;
+    }
+
+    r = snap_create(*ictx, snap_name);
+    if (r < 0) {
+      return r;
+    }
+
+    m_snaps.push_back(std::make_pair(snap_name, snap_protect));
+    if (snap_protect) {
+      r = ictx->operations->snap_protect(cls::rbd::UserSnapshotNamespace(), snap_name);
+      if (r < 0) {
+	return r;
+      }
+    }
+    close_image(ictx);
+    return 0;
+  }
+
+  Snaps m_snaps;
+};
+
+class DummyContext : public Context {
+public:
+  void finish(int r) override {
+  }
+};
+
+void generate_random_iomap(librbd::Image &image, int num_objects, int object_size,
+                           int max_count, map<uint64_t, uint64_t> &iomap)
+{
+  uint64_t stripe_unit, stripe_count;
+
+  stripe_unit = image.get_stripe_unit();
+  stripe_count = image.get_stripe_count();
+
+  while (max_count-- > 0) {
+    // generate random image offset based on base random object
+    // number and object offset and then map that back to an
+    // object number based on stripe unit and count.
+    uint64_t ono = rand() % num_objects;
+    uint64_t offset = rand() % (object_size - TEST_IO_SIZE);
+    uint64_t imageoff = (ono * object_size) + offset;
+
+    file_layout_t layout;
+    layout.object_size = object_size;
+    layout.stripe_unit = stripe_unit;
+    layout.stripe_count = stripe_count;
+
+    vector<ObjectExtent> ex;
+    Striper::file_to_extents(g_ceph_context, 1, &layout, imageoff, TEST_IO_SIZE, 0, ex);
+
+    // lets not worry if IO spans multiple extents (>1 object). in such
+    // as case we would perform the write multiple times to the same
+    // offset, but we record all objects that would be generated with
+    // this IO. TODO: fix this if such a need is required by your
+    // test.
+    vector<ObjectExtent>::iterator it;
+    map<uint64_t, uint64_t> curr_iomap;
+    for (it = ex.begin(); it != ex.end(); ++it) {
+      if (iomap.find((*it).objectno) != iomap.end()) {
+        break;
+      }
+
+      curr_iomap.insert(make_pair((*it).objectno, imageoff));
+    }
+
+    if (it == ex.end()) {
+      iomap.insert(curr_iomap.begin(), curr_iomap.end());
+    }
+  }
+}
+
+static bool is_sparsify_supported(librados::IoCtx &ioctx,
+                                  const std::string &oid) {
+  EXPECT_EQ(0, ioctx.create(oid, true));
+  int r = librbd::cls_client::sparsify(&ioctx, oid, 16, true);
+  EXPECT_TRUE(r == 0 || r == -EOPNOTSUPP);
+  ioctx.remove(oid);
+
+  return (r == 0);
+}
+
+static bool is_sparse_read_supported(librados::IoCtx &ioctx,
+                                     const std::string &oid) {
+  EXPECT_EQ(0, ioctx.create(oid, true));
+  bufferlist inbl;
+  inbl.append(std::string(1, 'X'));
+  EXPECT_EQ(0, ioctx.write(oid, inbl, inbl.length(), 1));
+  EXPECT_EQ(0, ioctx.write(oid, inbl, inbl.length(), 3));
+
+  std::map<uint64_t, uint64_t> m;
+  bufferlist outbl;
+  int r = ioctx.sparse_read(oid, m, outbl, 4, 0);
+  ioctx.remove(oid);
+
+  int expected_r = 2;
+  std::map<uint64_t, uint64_t> expected_m = {{1, 1}, {3, 1}};
+  bufferlist expected_outbl;
+  expected_outbl.append(std::string(2, 'X'));
+
+  return (r == expected_r && m == expected_m &&
+          outbl.contents_equal(expected_outbl));
+}
+
+TEST_F(TestInternal, OpenByID) {
+   REQUIRE_FORMAT_V2();
+
+   librbd::ImageCtx *ictx;
+   ASSERT_EQ(0, open_image(m_image_name, &ictx));
+   std::string id = ictx->id;
+   close_image(ictx);
+
+   ictx = new librbd::ImageCtx("", id, nullptr, m_ioctx, true);
+   ASSERT_EQ(0, ictx->state->open(0));
+   ASSERT_EQ(ictx->name, m_image_name);
+   close_image(ictx);
+}
+
+TEST_F(TestInternal, OpenSnapDNE) {
+   librbd::ImageCtx *ictx;
+   ASSERT_EQ(0, open_image(m_image_name, &ictx));
+
+   ictx = new librbd::ImageCtx(m_image_name, "", "unknown_snap", m_ioctx, true);
+   ASSERT_EQ(-ENOENT, ictx->state->open(librbd::OPEN_FLAG_SKIP_OPEN_PARENT));
+}
+
+TEST_F(TestInternal, IsExclusiveLockOwner) {
+  REQUIRE_FEATURE(RBD_FEATURE_EXCLUSIVE_LOCK);
+
+  librbd::ImageCtx *ictx;
+  ASSERT_EQ(0, open_image(m_image_name, &ictx));
+
+  bool is_owner;
+  ASSERT_EQ(0, librbd::is_exclusive_lock_owner(ictx, &is_owner));
+  ASSERT_FALSE(is_owner);
+
+  C_SaferCond ctx;
+  {
+    std::unique_lock l{ictx->owner_lock};
+    ictx->exclusive_lock->try_acquire_lock(&ctx);
+  }
+  ASSERT_EQ(0, ctx.wait());
+  ASSERT_EQ(0, librbd::is_exclusive_lock_owner(ictx, &is_owner));
+  ASSERT_TRUE(is_owner);
+}
+
+TEST_F(TestInternal, ResizeLocksImage) {
+  REQUIRE_FEATURE(RBD_FEATURE_EXCLUSIVE_LOCK);
+
+  librbd::ImageCtx *ictx;
+  ASSERT_EQ(0, open_image(m_image_name, &ictx));
+
+  librbd::NoOpProgressContext no_op;
+  ASSERT_EQ(0, ictx->operations->resize(m_image_size >> 1, true, no_op));
+
+  bool is_owner;
+  ASSERT_EQ(0, librbd::is_exclusive_lock_owner(ictx, &is_owner));
+  ASSERT_TRUE(is_owner);
+}
+
+TEST_F(TestInternal, ResizeFailsToLockImage) {
+  REQUIRE_FEATURE(RBD_FEATURE_EXCLUSIVE_LOCK);
+
+  librbd::ImageCtx *ictx;
+  ASSERT_EQ(0, open_image(m_image_name, &ictx));
+  ASSERT_EQ(0, lock_image(*ictx, ClsLockType::EXCLUSIVE, "manually locked"));
+
+  librbd::NoOpProgressContext no_op;
+  ASSERT_EQ(-EROFS, ictx->operations->resize(m_image_size >> 1, true, no_op));
+}
+
+TEST_F(TestInternal, SnapCreateLocksImage) {
+  REQUIRE_FEATURE(RBD_FEATURE_EXCLUSIVE_LOCK);
+
+  librbd::ImageCtx *ictx;
+  ASSERT_EQ(0, open_image(m_image_name, &ictx));
+
+  ASSERT_EQ(0, snap_create(*ictx, "snap1"));
+  BOOST_SCOPE_EXIT( (ictx) ) {
+    ASSERT_EQ(0,
+	      ictx->operations->snap_remove(cls::rbd::UserSnapshotNamespace(),
+					    "snap1"));
+  } BOOST_SCOPE_EXIT_END;
+
+  bool is_owner;
+  ASSERT_EQ(0, librbd::is_exclusive_lock_owner(ictx, &is_owner));
+  ASSERT_TRUE(is_owner);
+}
+
+TEST_F(TestInternal, SnapCreateFailsToLockImage) {
+  REQUIRE_FEATURE(RBD_FEATURE_EXCLUSIVE_LOCK);
+
+  librbd::ImageCtx *ictx;
+  ASSERT_EQ(0, open_image(m_image_name, &ictx));
+  ASSERT_EQ(0, lock_image(*ictx, ClsLockType::EXCLUSIVE, "manually locked"));
+
+  ASSERT_EQ(-EROFS, snap_create(*ictx, "snap1"));
+}
+
+TEST_F(TestInternal, SnapRollbackLocksImage) {
+  REQUIRE_FEATURE(RBD_FEATURE_EXCLUSIVE_LOCK);
+
+  ASSERT_EQ(0, create_snapshot("snap1", false));
+
+  librbd::ImageCtx *ictx;
+  ASSERT_EQ(0, open_image(m_image_name, &ictx));
+
+  librbd::NoOpProgressContext no_op;
+  ASSERT_EQ(0, ictx->operations->snap_rollback(cls::rbd::UserSnapshotNamespace(),
+					       "snap1",
+					       no_op));
+
+  bool is_owner;
+  ASSERT_EQ(0, librbd::is_exclusive_lock_owner(ictx, &is_owner));
+  ASSERT_TRUE(is_owner);
+}
+
+TEST_F(TestInternal, SnapRollbackFailsToLockImage) {
+  REQUIRE_FEATURE(RBD_FEATURE_EXCLUSIVE_LOCK);
+
+
+  ASSERT_EQ(0, create_snapshot("snap1", false));
+
+  librbd::ImageCtx *ictx;
+  ASSERT_EQ(0, open_image(m_image_name, &ictx));
+  ASSERT_EQ(0, lock_image(*ictx, ClsLockType::EXCLUSIVE, "manually locked"));
+
+  librbd::NoOpProgressContext no_op;
+  ASSERT_EQ(-EROFS,
+	    ictx->operations->snap_rollback(cls::rbd::UserSnapshotNamespace(),
+					    "snap1",
+					    no_op));
+}
+
+TEST_F(TestInternal, SnapSetReleasesLock) {
+  REQUIRE_FEATURE(RBD_FEATURE_EXCLUSIVE_LOCK);
+
+  ASSERT_EQ(0, create_snapshot("snap1", false));
+
+  librbd::ImageCtx *ictx;
+  ASSERT_EQ(0, open_image(m_image_name, &ictx));
+  ASSERT_EQ(0, librbd::api::Image<>::snap_set(
+                 ictx, cls::rbd::UserSnapshotNamespace(), "snap1"));
+
+  bool is_owner;
+  ASSERT_EQ(0, librbd::is_exclusive_lock_owner(ictx, &is_owner));
+  ASSERT_FALSE(is_owner);
+}
+
+TEST_F(TestInternal, FlattenLocksImage) {
+  REQUIRE_FEATURE(RBD_FEATURE_EXCLUSIVE_LOCK | RBD_FEATURE_LAYERING);
+
+  ASSERT_EQ(0, create_snapshot("snap1", true));
+
+  librbd::ImageCtx *ictx;
+  ASSERT_EQ(0, open_image(m_image_name, &ictx));
+
+  uint64_t features;
+  ASSERT_EQ(0, librbd::get_features(ictx, &features));
+
+  std::string clone_name = get_temp_image_name();
+  int order = ictx->order;
+  ASSERT_EQ(0, librbd::clone(m_ioctx, m_image_name.c_str(), "snap1", m_ioctx,
+			     clone_name.c_str(), features, &order, 0, 0));
+
+  librbd::ImageCtx *ictx2;
+  ASSERT_EQ(0, open_image(clone_name, &ictx2));
+
+  librbd::NoOpProgressContext no_op;
+  ASSERT_EQ(0, ictx2->operations->flatten(no_op));
+
+  bool is_owner;
+  ASSERT_EQ(0, librbd::is_exclusive_lock_owner(ictx2, &is_owner));
+  ASSERT_TRUE(is_owner);
+}
+
+TEST_F(TestInternal, FlattenFailsToLockImage) {
+  REQUIRE_FEATURE(RBD_FEATURE_EXCLUSIVE_LOCK | RBD_FEATURE_LAYERING);
+
+  ASSERT_EQ(0, create_snapshot("snap1", true));
+
+  librbd::ImageCtx *ictx;
+  ASSERT_EQ(0, open_image(m_image_name, &ictx));
+
+  uint64_t features;
+  ASSERT_EQ(0, librbd::get_features(ictx, &features));
+
+  std::string clone_name = get_temp_image_name();
+  int order = ictx->order;
+  ASSERT_EQ(0, librbd::clone(m_ioctx, m_image_name.c_str(), "snap1", m_ioctx,
+                             clone_name.c_str(), features, &order, 0, 0));
+
+  TestInternal *parent = this;
+  librbd::ImageCtx *ictx2 = NULL;
+  BOOST_SCOPE_EXIT( (&m_ioctx) (clone_name) (parent) (&ictx2) ) {
+    if (ictx2 != NULL) {
+      parent->close_image(ictx2);
+      parent->unlock_image();
+    }
+    librbd::NoOpProgressContext no_op;
+    ASSERT_EQ(0, librbd::api::Image<>::remove(m_ioctx, clone_name, no_op));
+  } BOOST_SCOPE_EXIT_END;
+
+  ASSERT_EQ(0, open_image(clone_name, &ictx2));
+  ASSERT_EQ(0, lock_image(*ictx2, ClsLockType::EXCLUSIVE, "manually locked"));
+
+  librbd::NoOpProgressContext no_op;
+  ASSERT_EQ(-EROFS, ictx2->operations->flatten(no_op));
+}
+
+TEST_F(TestInternal, AioWriteRequestsLock) {
+  REQUIRE_FEATURE(RBD_FEATURE_EXCLUSIVE_LOCK);
+
+  librbd::ImageCtx *ictx;
+  ASSERT_EQ(0, open_image(m_image_name, &ictx));
+  ASSERT_EQ(0, lock_image(*ictx, ClsLockType::EXCLUSIVE, "manually locked"));
+
+  std::string buffer(256, '1');
+  Context *ctx = new DummyContext();
+  auto c = librbd::io::AioCompletion::create(ctx);
+  c->get();
+
+  bufferlist bl;
+  bl.append(buffer);
+  api::Io<>::aio_write(*ictx, c, 0, buffer.size(), std::move(bl), 0, true);
+
+  bool is_owner;
+  ASSERT_EQ(0, librbd::is_exclusive_lock_owner(ictx, &is_owner));
+  ASSERT_FALSE(is_owner);
+  ASSERT_FALSE(c->is_complete());
+
+  unlock_image();
+  ASSERT_EQ(0, c->wait_for_complete());
+  c->put();
+}
+
+TEST_F(TestInternal, AioDiscardRequestsLock) {
+  REQUIRE_FEATURE(RBD_FEATURE_EXCLUSIVE_LOCK);
+
+  librbd::ImageCtx *ictx;
+  ASSERT_EQ(0, open_image(m_image_name, &ictx));
+  ASSERT_EQ(0, lock_image(*ictx, ClsLockType::EXCLUSIVE, "manually locked"));
+
+  Context *ctx = new DummyContext();
+  auto c = librbd::io::AioCompletion::create(ctx);
+  c->get();
+  api::Io<>::aio_discard(*ictx, c, 0, 256, false, true);
+
+  bool is_owner;
+  ASSERT_EQ(0, librbd::is_exclusive_lock_owner(ictx, &is_owner));
+  ASSERT_FALSE(is_owner);
+  ASSERT_FALSE(c->is_complete());
+
+  unlock_image();
+  ASSERT_EQ(0, c->wait_for_complete());
+  c->put();
+}
+
+TEST_F(TestInternal, CancelAsyncResize) {
+  REQUIRE_FEATURE(RBD_FEATURE_EXCLUSIVE_LOCK);
+
+  librbd::ImageCtx *ictx;
+  ASSERT_EQ(0, open_image(m_image_name, &ictx));
+
+  C_SaferCond ctx;
+  {
+    std::unique_lock l{ictx->owner_lock};
+    ictx->exclusive_lock->try_acquire_lock(&ctx);
+  }
+
+  ASSERT_EQ(0, ctx.wait());
+  {
+    std::shared_lock owner_locker{ictx->owner_lock};
+    ASSERT_TRUE(ictx->exclusive_lock->is_lock_owner());
+  }
+
+  uint64_t size;
+  ASSERT_EQ(0, librbd::get_size(ictx, &size));
+
+  uint32_t attempts = 0;
+  while (attempts++ < 20 && size > 0) {
+    C_SaferCond ctx;
+    librbd::NoOpProgressContext prog_ctx;
+
+    size -= std::min<uint64_t>(size, 1 << 18);
+    {
+      std::shared_lock l{ictx->owner_lock};
+      ictx->operations->execute_resize(size, true, prog_ctx, &ctx, 0);
+    }
+
+    // try to interrupt the in-progress resize
+    ictx->cancel_async_requests();
+
+    int r = ctx.wait();
+    if (r == -ERESTART) {
+      std::cout << "detected canceled async request" << std::endl;
+      break;
+    }
+    ASSERT_EQ(0, r);
+  }
+}
+
+TEST_F(TestInternal, MultipleResize) {
+  librbd::ImageCtx *ictx;
+  ASSERT_EQ(0, open_image(m_image_name, &ictx));
+
+  if (ictx->exclusive_lock != nullptr) {
+    C_SaferCond ctx;
+    {
+      std::unique_lock l{ictx->owner_lock};
+      ictx->exclusive_lock->try_acquire_lock(&ctx);
+    }
+
+    std::shared_lock owner_locker{ictx->owner_lock};
+    ASSERT_EQ(0, ctx.wait());
+    ASSERT_TRUE(ictx->exclusive_lock->is_lock_owner());
+  }
+
+  uint64_t size;
+  ASSERT_EQ(0, librbd::get_size(ictx, &size));
+  uint64_t original_size = size;
+
+  std::vector<C_SaferCond*> contexts;
+
+  uint32_t attempts = 0;
+  librbd::NoOpProgressContext prog_ctx;
+  while (size > 0) {
+    uint64_t new_size = original_size;
+    if (attempts++ % 2 == 0) {
+      size -= std::min<uint64_t>(size, 1 << 18);
+      new_size = size;
+    }
+
+    std::shared_lock l{ictx->owner_lock};
+    contexts.push_back(new C_SaferCond());
+    ictx->operations->execute_resize(new_size, true, prog_ctx, contexts.back(), 0);
+  }
+
+  for (uint32_t i = 0; i < contexts.size(); ++i) {
+    ASSERT_EQ(0, contexts[i]->wait());
+    delete contexts[i];
+  }
+
+  ASSERT_EQ(0, librbd::get_size(ictx, &size));
+  ASSERT_EQ(0U, size);
+}
+
+TEST_F(TestInternal, Metadata) {
+  REQUIRE_FEATURE(RBD_FEATURE_LAYERING);
+
+  map<string, bool> test_confs = boost::assign::map_list_of(
+    "aaaaaaa", false)(
+    "bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb", false)(
+    "cccccccccccccc", false);
+  map<string, bool>::iterator it = test_confs.begin();
+  int r;
+  librbd::ImageCtx *ictx;
+  ASSERT_EQ(0, open_image(m_image_name, &ictx));
+
+  r = ictx->operations->metadata_set(it->first, "value1");
+  ASSERT_EQ(0, r);
+  ++it;
+  r = ictx->operations->metadata_set(it->first, "value2");
+  ASSERT_EQ(0, r);
+  ++it;
+  r = ictx->operations->metadata_set(it->first, "value3");
+  ASSERT_EQ(0, r);
+  r = ictx->operations->metadata_set("abcd", "value4");
+  ASSERT_EQ(0, r);
+  r = ictx->operations->metadata_set("xyz", "value5");
+  ASSERT_EQ(0, r);
+  map<string, bufferlist> pairs;
+  r = librbd::metadata_list(ictx, "", 0, &pairs);
+  ASSERT_EQ(0, r);
+
+  uint8_t original_pairs_num = 0;
+  if (ictx->test_features(RBD_FEATURE_DIRTY_CACHE)) {
+    original_pairs_num = 1;
+  }
+  ASSERT_EQ(original_pairs_num + 5, pairs.size());
+  r = ictx->operations->metadata_remove("abcd");
+  ASSERT_EQ(0, r);
+  r = ictx->operations->metadata_remove("xyz");
+  ASSERT_EQ(0, r);
+  pairs.clear();
+  r = librbd::metadata_list(ictx, "", 0, &pairs);
+  ASSERT_EQ(0, r);
+  ASSERT_EQ(original_pairs_num + 3, pairs.size());
+  string val;
+  r = librbd::metadata_get(ictx, it->first, &val);
+  ASSERT_EQ(0, r);
+  ASSERT_STREQ(val.c_str(), "value3");
+}
+
+TEST_F(TestInternal, MetadataConfApply) {
+  REQUIRE_FEATURE(RBD_FEATURE_LAYERING);
+
+  librbd::ImageCtx *ictx;
+  ASSERT_EQ(0, open_image(m_image_name, &ictx));
+
+  ASSERT_EQ(-ENOENT, ictx->operations->metadata_remove("conf_rbd_cache"));
+
+  bool cache = ictx->cache;
+  std::string rbd_conf_cache = cache ? "true" : "false";
+  std::string new_rbd_conf_cache = !cache ? "true" : "false";
+
+  ASSERT_EQ(0, ictx->operations->metadata_set("conf_rbd_cache",
+                                              new_rbd_conf_cache));
+  ASSERT_EQ(!cache, ictx->cache);
+
+  ASSERT_EQ(0, ictx->operations->metadata_remove("conf_rbd_cache"));
+  ASSERT_EQ(cache, ictx->cache);
+}
+
+TEST_F(TestInternal, SnapshotCopyup)
+{
+  REQUIRE_FEATURE(RBD_FEATURE_LAYERING);
+
+  librbd::ImageCtx *ictx;
+  ASSERT_EQ(0, open_image(m_image_name, &ictx));
+
+  bool sparse_read_supported = is_sparse_read_supported(
+      ictx->data_ctx, ictx->get_object_name(10));
+
+  bufferlist bl;
+  bl.append(std::string(256, '1'));
+  ASSERT_EQ(256, api::Io<>::write(*ictx, 0, bl.length(), bufferlist{bl}, 0));
+  ASSERT_EQ(256, api::Io<>::write(*ictx, 1024, bl.length(), bufferlist{bl},
+                                  0));
+
+  ASSERT_EQ(0, snap_create(*ictx, "snap1"));
+  ASSERT_EQ(0,
+	    ictx->operations->snap_protect(cls::rbd::UserSnapshotNamespace(),
+					   "snap1"));
+
+  uint64_t features;
+  ASSERT_EQ(0, librbd::get_features(ictx, &features));
+
+  std::string clone_name = get_temp_image_name();
+  int order = ictx->order;
+  ASSERT_EQ(0, librbd::clone(m_ioctx, m_image_name.c_str(), "snap1", m_ioctx,
+			     clone_name.c_str(), features, &order, 0, 0));
+
+  librbd::ImageCtx *ictx2;
+  ASSERT_EQ(0, open_image(clone_name, &ictx2));
+
+  ASSERT_EQ(0, snap_create(*ictx2, "snap1"));
+  ASSERT_EQ(0, snap_create(*ictx2, "snap2"));
+
+  ASSERT_EQ(256, api::Io<>::write(*ictx2, 256, bl.length(), bufferlist{bl},
+                                  0));
+
+  ASSERT_EQ(0, flush_writeback_cache(ictx2));
+  librados::IoCtx snap_ctx;
+  snap_ctx.dup(ictx2->data_ctx);
+  snap_ctx.snap_set_read(CEPH_SNAPDIR);
+
+  librados::snap_set_t snap_set;
+  ASSERT_EQ(0, snap_ctx.list_snaps(ictx2->get_object_name(0), &snap_set));
+
+  uint64_t copyup_end = ictx2->enable_sparse_copyup ? 1024 + 256 : 1 << order;
+  std::vector< std::pair<uint64_t,uint64_t> > expected_overlap =
+    boost::assign::list_of(
+      std::make_pair(0, 256))(
+      std::make_pair(512, copyup_end - 512));
+  ASSERT_EQ(2U, snap_set.clones.size());
+  ASSERT_NE(CEPH_NOSNAP, snap_set.clones[0].cloneid);
+  ASSERT_EQ(2U, snap_set.clones[0].snaps.size());
+  ASSERT_EQ(expected_overlap, snap_set.clones[0].overlap);
+  ASSERT_EQ(CEPH_NOSNAP, snap_set.clones[1].cloneid);
+
+  bufferptr read_ptr(256);
+  bufferlist read_bl;
+  read_bl.push_back(read_ptr);
+
+  std::list<std::string> snaps = {"snap1", "snap2", ""};
+  librbd::io::ReadResult read_result{&read_bl};
+  for (std::list<std::string>::iterator it = snaps.begin();
+       it != snaps.end(); ++it) {
+    const char *snap_name = it->empty() ? NULL : it->c_str();
+    ASSERT_EQ(0, librbd::api::Image<>::snap_set(
+                   ictx2, cls::rbd::UserSnapshotNamespace(), snap_name));
+
+    ASSERT_EQ(256,
+              api::Io<>::read(*ictx2, 0, 256,
+                              librbd::io::ReadResult{read_result}, 0));
+    ASSERT_TRUE(bl.contents_equal(read_bl));
+
+    ASSERT_EQ(256,
+              api::Io<>::read(*ictx2, 1024, 256,
+                              librbd::io::ReadResult{read_result}, 0));
+    ASSERT_TRUE(bl.contents_equal(read_bl));
+
+    ASSERT_EQ(256,
+              api::Io<>::read(*ictx2, 256, 256,
+                              librbd::io::ReadResult{read_result}, 0));
+    if (snap_name == NULL) {
+      ASSERT_TRUE(bl.contents_equal(read_bl));
+    } else {
+      ASSERT_TRUE(read_bl.is_zero());
+    }
+
+    // verify sparseness was preserved
+    {
+      librados::IoCtx io_ctx;
+      io_ctx.dup(m_ioctx);
+      librados::Rados rados(io_ctx);
+      EXPECT_EQ(0, rados.conf_set("rbd_cache", "false"));
+      EXPECT_EQ(0, rados.conf_set("rbd_sparse_read_threshold_bytes", "256"));
+      auto ictx3 = new librbd::ImageCtx(clone_name, "", snap_name, io_ctx,
+                                        true);
+      ASSERT_EQ(0, ictx3->state->open(0));
+      BOOST_SCOPE_EXIT(ictx3) {
+        ictx3->state->close();
+      } BOOST_SCOPE_EXIT_END;
+      std::vector<std::pair<uint64_t, uint64_t>> expected_m;
+      bufferlist expected_bl;
+      if (ictx3->enable_sparse_copyup && sparse_read_supported) {
+        if (snap_name == NULL) {
+          expected_m = {{0, 512}, {1024, 256}};
+          expected_bl.append(std::string(256 * 3, '1'));
+        } else {
+          expected_m = {{0, 256}, {1024, 256}};
+          expected_bl.append(std::string(256 * 2, '1'));
+        }
+      } else {
+        expected_m = {{0, 1024 + 256}};
+        if (snap_name == NULL) {
+          expected_bl.append(std::string(256 * 2, '1'));
+          expected_bl.append(std::string(256 * 2, '\0'));
+          expected_bl.append(std::string(256 * 1, '1'));
+        } else {
+          expected_bl.append(std::string(256 * 1, '1'));
+          expected_bl.append(std::string(256 * 3, '\0'));
+          expected_bl.append(std::string(256 * 1, '1'));
+        }
+      }
+      std::vector<std::pair<uint64_t, uint64_t>> read_m;
+      librbd::io::ReadResult sparse_read_result{&read_m, &read_bl};
+      EXPECT_EQ(1024 + 256,
+                api::Io<>::read(*ictx3, 0, 1024 + 256,
+                                librbd::io::ReadResult{sparse_read_result}, 0));
+      EXPECT_EQ(expected_m, read_m);
+      EXPECT_TRUE(expected_bl.contents_equal(read_bl));
+    }
+
+    // verify the object map was properly updated
+    if ((ictx2->features & RBD_FEATURE_OBJECT_MAP) != 0) {
+      uint8_t state = OBJECT_EXISTS;
+      if ((ictx2->features & RBD_FEATURE_FAST_DIFF) != 0 &&
+          it != snaps.begin() && snap_name != NULL) {
+        state = OBJECT_EXISTS_CLEAN;
+      }
+
+      librbd::ObjectMap<> *object_map = new librbd::ObjectMap<>(*ictx2, ictx2->snap_id);
+      C_SaferCond ctx;
+      object_map->open(&ctx);
+      ASSERT_EQ(0, ctx.wait());
+
+      std::shared_lock image_locker{ictx2->image_lock};
+      ASSERT_EQ(state, (*object_map)[0]);
+      object_map->put();
+    }
+  }
+}
+
+TEST_F(TestInternal, SnapshotCopyupZeros)
+{
+  REQUIRE_FEATURE(RBD_FEATURE_LAYERING);
+
+  librbd::ImageCtx *ictx;
+  ASSERT_EQ(0, open_image(m_image_name, &ictx));
+
+  // create an empty clone
+  ASSERT_EQ(0, snap_create(*ictx, "snap1"));
+  ASSERT_EQ(0,
+	    ictx->operations->snap_protect(cls::rbd::UserSnapshotNamespace(),
+					   "snap1"));
+
+  uint64_t features;
+  ASSERT_EQ(0, librbd::get_features(ictx, &features));
+
+  std::string clone_name = get_temp_image_name();
+  int order = ictx->order;
+  ASSERT_EQ(0, librbd::clone(m_ioctx, m_image_name.c_str(), "snap1", m_ioctx,
+			     clone_name.c_str(), features, &order, 0, 0));
+
+  librbd::ImageCtx *ictx2;
+  ASSERT_EQ(0, open_image(clone_name, &ictx2));
+
+  ASSERT_EQ(0, snap_create(*ictx2, "snap1"));
+
+  bufferlist bl;
+  bl.append(std::string(256, '1'));
+  ASSERT_EQ(256, api::Io<>::write(*ictx2, 256, bl.length(), bufferlist{bl}, 0));
+
+  ASSERT_EQ(0, flush_writeback_cache(ictx2));
+
+  librados::IoCtx snap_ctx;
+  snap_ctx.dup(ictx2->data_ctx);
+  snap_ctx.snap_set_read(CEPH_SNAPDIR);
+
+  librados::snap_set_t snap_set;
+  ASSERT_EQ(0, snap_ctx.list_snaps(ictx2->get_object_name(0), &snap_set));
+
+  // verify that snapshot wasn't affected
+  ASSERT_EQ(1U, snap_set.clones.size());
+  ASSERT_EQ(CEPH_NOSNAP, snap_set.clones[0].cloneid);
+
+  bufferptr read_ptr(256);
+  bufferlist read_bl;
+  read_bl.push_back(read_ptr);
+
+  std::list<std::string> snaps = {"snap1", ""};
+  librbd::io::ReadResult read_result{&read_bl};
+  for (std::list<std::string>::iterator it = snaps.begin();
+       it != snaps.end(); ++it) {
+    const char *snap_name = it->empty() ? NULL : it->c_str();
+    ASSERT_EQ(0, librbd::api::Image<>::snap_set(
+                   ictx2, cls::rbd::UserSnapshotNamespace(), snap_name));
+
+    ASSERT_EQ(256,
+              api::Io<>::read(*ictx2, 0, 256,
+                              librbd::io::ReadResult{read_result}, 0));
+    ASSERT_TRUE(read_bl.is_zero());
+
+    ASSERT_EQ(256,
+              api::Io<>::read(*ictx2, 256, 256,
+                              librbd::io::ReadResult{read_result}, 0));
+    if (snap_name == NULL) {
+      ASSERT_TRUE(bl.contents_equal(read_bl));
+    } else {
+      ASSERT_TRUE(read_bl.is_zero());
+    }
+
+    // verify that only HEAD object map was updated
+    if ((ictx2->features & RBD_FEATURE_OBJECT_MAP) != 0) {
+      uint8_t state = OBJECT_EXISTS;
+      if (snap_name != NULL) {
+        state = OBJECT_NONEXISTENT;
+      }
+
+      librbd::ObjectMap<> *object_map = new librbd::ObjectMap<>(*ictx2, ictx2->snap_id);
+      C_SaferCond ctx;
+      object_map->open(&ctx);
+      ASSERT_EQ(0, ctx.wait());
+
+      std::shared_lock image_locker{ictx2->image_lock};
+      ASSERT_EQ(state, (*object_map)[0]);
+      object_map->put();
+    }
+  }
+}
+
+TEST_F(TestInternal, SnapshotCopyupZerosMigration)
+{
+  REQUIRE_FEATURE(RBD_FEATURE_LAYERING);
+
+  librbd::ImageCtx *ictx;
+  ASSERT_EQ(0, open_image(m_image_name, &ictx));
+
+  uint64_t features;
+  ASSERT_EQ(0, librbd::get_features(ictx, &features));
+
+  close_image(ictx);
+
+  // migrate an empty image
+  std::string dst_name = get_temp_image_name();
+  librbd::ImageOptions dst_opts;
+  dst_opts.set(RBD_IMAGE_OPTION_FEATURES, features);
+  ASSERT_EQ(0, librbd::api::Migration<>::prepare(m_ioctx, m_image_name,
+                                                 m_ioctx, dst_name,
+                                                 dst_opts));
+
+  librbd::ImageCtx *ictx2;
+  ASSERT_EQ(0, open_image(dst_name, &ictx2));
+
+  ASSERT_EQ(0, snap_create(*ictx2, "snap1"));
+
+  bufferlist bl;
+  bl.append(std::string(256, '1'));
+  ASSERT_EQ(256, api::Io<>::write(*ictx2, 256, bl.length(), bufferlist{bl}, 0));
+
+  librados::IoCtx snap_ctx;
+  snap_ctx.dup(ictx2->data_ctx);
+  snap_ctx.snap_set_read(CEPH_SNAPDIR);
+
+  librados::snap_set_t snap_set;
+  ASSERT_EQ(0, snap_ctx.list_snaps(ictx2->get_object_name(0), &snap_set));
+
+  // verify that snapshot wasn't affected
+  ASSERT_EQ(1U, snap_set.clones.size());
+  ASSERT_EQ(CEPH_NOSNAP, snap_set.clones[0].cloneid);
+
+  bufferptr read_ptr(256);
+  bufferlist read_bl;
+  read_bl.push_back(read_ptr);
+
+  std::list<std::string> snaps = {"snap1", ""};
+  librbd::io::ReadResult read_result{&read_bl};
+  for (std::list<std::string>::iterator it = snaps.begin();
+       it != snaps.end(); ++it) {
+    const char *snap_name = it->empty() ? NULL : it->c_str();
+    ASSERT_EQ(0, librbd::api::Image<>::snap_set(
+                   ictx2, cls::rbd::UserSnapshotNamespace(), snap_name));
+
+    ASSERT_EQ(256,
+              api::Io<>::read(*ictx2, 0, 256,
+                              librbd::io::ReadResult{read_result}, 0));
+    ASSERT_TRUE(read_bl.is_zero());
+
+    ASSERT_EQ(256,
+              api::Io<>::read(*ictx2, 256, 256,
+                              librbd::io::ReadResult{read_result}, 0));
+    if (snap_name == NULL) {
+      ASSERT_TRUE(bl.contents_equal(read_bl));
+    } else {
+      ASSERT_TRUE(read_bl.is_zero());
+    }
+
+    // verify that only HEAD object map was updated
+    if ((ictx2->features & RBD_FEATURE_OBJECT_MAP) != 0) {
+      uint8_t state = OBJECT_EXISTS;
+      if (snap_name != NULL) {
+        state = OBJECT_NONEXISTENT;
+      }
+
+      librbd::ObjectMap<> *object_map = new librbd::ObjectMap<>(*ictx2, ictx2->snap_id);
+      C_SaferCond ctx;
+      object_map->open(&ctx);
+      ASSERT_EQ(0, ctx.wait());
+
+      std::shared_lock image_locker{ictx2->image_lock};
+      ASSERT_EQ(state, (*object_map)[0]);
+      object_map->put();
+    }
+  }
+}
+
+TEST_F(TestInternal, ResizeCopyup)
+{
+  REQUIRE_FEATURE(RBD_FEATURE_LAYERING);
+
+  m_image_name = get_temp_image_name();
+  m_image_size = 1 << 14;
+
+  uint64_t features = 0;
+  ::get_features(&features);
+  int order = 12;
+  ASSERT_EQ(0, m_rbd.create2(m_ioctx, m_image_name.c_str(), m_image_size,
+                             features, &order));
+
+  librbd::ImageCtx *ictx;
+  ASSERT_EQ(0, open_image(m_image_name, &ictx));
+
+  bufferlist bl;
+  bl.append(std::string(4096, '1'));
+  for (size_t i = 0; i < m_image_size; i += bl.length()) {
+    ASSERT_EQ((ssize_t)bl.length(),
+	      api::Io<>::write(*ictx, i, bl.length(), bufferlist{bl}, 0));
+  }
+
+  ASSERT_EQ(0, snap_create(*ictx, "snap1"));
+  ASSERT_EQ(0,
+	    ictx->operations->snap_protect(cls::rbd::UserSnapshotNamespace(),
+					   "snap1"));
+
+  std::string clone_name = get_temp_image_name();
+  ASSERT_EQ(0, librbd::clone(m_ioctx, m_image_name.c_str(), "snap1", m_ioctx,
+			     clone_name.c_str(), features, &order, 0, 0));
+
+  librbd::ImageCtx *ictx2;
+  ASSERT_EQ(0, open_image(clone_name, &ictx2));
+  ASSERT_EQ(0, snap_create(*ictx2, "snap1"));
+
+  bufferptr read_ptr(bl.length());
+  bufferlist read_bl;
+  read_bl.push_back(read_ptr);
+
+  // verify full / partial object removal properly copyup
+  librbd::NoOpProgressContext no_op;
+  ASSERT_EQ(0, ictx2->operations->resize(m_image_size - (1 << order) - 32,
+                                         true, no_op));
+  ASSERT_EQ(0, ictx2->operations->resize(m_image_size - (2 << order) - 32,
+                                         true, no_op));
+  ASSERT_EQ(0, librbd::api::Image<>::snap_set(ictx2,
+				              cls::rbd::UserSnapshotNamespace(),
+				              "snap1"));
+
+  {
+    // hide the parent from the snapshot
+    std::unique_lock image_locker{ictx2->image_lock};
+    ictx2->snap_info.begin()->second.parent = librbd::ParentImageInfo();
+  }
+
+  librbd::io::ReadResult read_result{&read_bl};
+  for (size_t i = 2 << order; i < m_image_size; i += bl.length()) {
+    ASSERT_EQ((ssize_t)bl.length(),
+              api::Io<>::read(*ictx2, i, bl.length(),
+                              librbd::io::ReadResult{read_result}, 0));
+    ASSERT_TRUE(bl.contents_equal(read_bl));
+  }
+}
+
+TEST_F(TestInternal, DiscardCopyup)
+{
+  REQUIRE_FEATURE(RBD_FEATURE_LAYERING);
+
+  CephContext* cct = reinterpret_cast<CephContext*>(_rados.cct());
+  REQUIRE(!cct->_conf.get_val<bool>("rbd_skip_partial_discard"));
+
+  m_image_name = get_temp_image_name();
+  m_image_size = 1 << 14;
+
+  uint64_t features = 0;
+  ::get_features(&features);
+  int order = 12;
+  ASSERT_EQ(0, m_rbd.create2(m_ioctx, m_image_name.c_str(), m_image_size,
+                             features, &order));
+
+  librbd::ImageCtx *ictx;
+  ASSERT_EQ(0, open_image(m_image_name, &ictx));
+
+  bufferlist bl;
+  bl.append(std::string(4096, '1'));
+  for (size_t i = 0; i < m_image_size; i += bl.length()) {
+    ASSERT_EQ((ssize_t)bl.length(),
+	      api::Io<>::write(*ictx, i, bl.length(), bufferlist{bl}, 0));
+  }
+
+  ASSERT_EQ(0, snap_create(*ictx, "snap1"));
+  ASSERT_EQ(0,
+	    ictx->operations->snap_protect(cls::rbd::UserSnapshotNamespace(),
+					   "snap1"));
+
+  std::string clone_name = get_temp_image_name();
+  ASSERT_EQ(0, librbd::clone(m_ioctx, m_image_name.c_str(), "snap1", m_ioctx,
+			     clone_name.c_str(), features, &order, 0, 0));
+
+  librbd::ImageCtx *ictx2;
+  ASSERT_EQ(0, open_image(clone_name, &ictx2));
+
+  ASSERT_EQ(0, snap_create(*ictx2, "snap1"));
+
+  bufferptr read_ptr(bl.length());
+  bufferlist read_bl;
+  read_bl.push_back(read_ptr);
+
+  ASSERT_EQ(static_cast<int>(m_image_size - 64),
+            api::Io<>::discard(*ictx2, 32, m_image_size - 64, false));
+  ASSERT_EQ(0, librbd::api::Image<>::snap_set(ictx2,
+				              cls::rbd::UserSnapshotNamespace(),
+				              "snap1"));
+
+  {
+    // hide the parent from the snapshot
+    std::unique_lock image_locker{ictx2->image_lock};
+    ictx2->snap_info.begin()->second.parent = librbd::ParentImageInfo();
+  }
+
+  librbd::io::ReadResult read_result{&read_bl};
+  for (size_t i = 0; i < m_image_size; i += bl.length()) {
+    ASSERT_EQ((ssize_t)bl.length(),
+              api::Io<>::read(*ictx2, i, bl.length(),
+                              librbd::io::ReadResult{read_result}, 0));
+    ASSERT_TRUE(bl.contents_equal(read_bl));
+  }
+}
+
+TEST_F(TestInternal, ImageOptions) {
+  rbd_image_options_t opts1 = NULL, opts2 = NULL;
+  uint64_t uint64_val1 = 10, uint64_val2 = 0;
+  std::string string_val1;
+
+  librbd::image_options_create(&opts1);
+  ASSERT_NE((rbd_image_options_t)NULL, opts1);
+  ASSERT_TRUE(librbd::image_options_is_empty(opts1));
+
+  ASSERT_EQ(-EINVAL, librbd::image_options_get(opts1, RBD_IMAGE_OPTION_FEATURES,
+	  &string_val1));
+  ASSERT_EQ(-ENOENT, librbd::image_options_get(opts1, RBD_IMAGE_OPTION_FEATURES,
+	  &uint64_val1));
+
+  ASSERT_EQ(-EINVAL, librbd::image_options_set(opts1, RBD_IMAGE_OPTION_FEATURES,
+	  string_val1));
+
+  ASSERT_EQ(0, librbd::image_options_set(opts1, RBD_IMAGE_OPTION_FEATURES,
+	  uint64_val1));
+  ASSERT_FALSE(librbd::image_options_is_empty(opts1));
+  ASSERT_EQ(0, librbd::image_options_get(opts1, RBD_IMAGE_OPTION_FEATURES,
+	  &uint64_val2));
+  ASSERT_EQ(uint64_val1, uint64_val2);
+
+  librbd::image_options_create_ref(&opts2, opts1);
+  ASSERT_NE((rbd_image_options_t)NULL, opts2);
+  ASSERT_FALSE(librbd::image_options_is_empty(opts2));
+
+  uint64_val2 = 0;
+  ASSERT_NE(uint64_val1, uint64_val2);
+  ASSERT_EQ(0, librbd::image_options_get(opts2, RBD_IMAGE_OPTION_FEATURES,
+	  &uint64_val2));
+  ASSERT_EQ(uint64_val1, uint64_val2);
+
+  uint64_val2++;
+  ASSERT_NE(uint64_val1, uint64_val2);
+  ASSERT_EQ(-ENOENT, librbd::image_options_get(opts1, RBD_IMAGE_OPTION_ORDER,
+	  &uint64_val1));
+  ASSERT_EQ(-ENOENT, librbd::image_options_get(opts2, RBD_IMAGE_OPTION_ORDER,
+	  &uint64_val2));
+  ASSERT_EQ(0, librbd::image_options_set(opts2, RBD_IMAGE_OPTION_ORDER,
+	  uint64_val2));
+  ASSERT_EQ(0, librbd::image_options_get(opts1, RBD_IMAGE_OPTION_ORDER,
+	  &uint64_val1));
+  ASSERT_EQ(0, librbd::image_options_get(opts2, RBD_IMAGE_OPTION_ORDER,
+	  &uint64_val2));
+  ASSERT_EQ(uint64_val1, uint64_val2);
+
+  librbd::image_options_destroy(opts1);
+
+  uint64_val2++;
+  ASSERT_NE(uint64_val1, uint64_val2);
+  ASSERT_EQ(0, librbd::image_options_get(opts2, RBD_IMAGE_OPTION_ORDER,
+	  &uint64_val2));
+  ASSERT_EQ(uint64_val1, uint64_val2);
+
+  ASSERT_EQ(0, librbd::image_options_unset(opts2, RBD_IMAGE_OPTION_ORDER));
+  ASSERT_EQ(-ENOENT, librbd::image_options_unset(opts2, RBD_IMAGE_OPTION_ORDER));
+
+  librbd::image_options_clear(opts2);
+  ASSERT_EQ(-ENOENT, librbd::image_options_get(opts2, RBD_IMAGE_OPTION_FEATURES,
+	  &uint64_val2));
+  ASSERT_TRUE(librbd::image_options_is_empty(opts2));
+
+  librbd::image_options_destroy(opts2);
+}
+
+TEST_F(TestInternal, WriteFullCopyup) {
+  REQUIRE_FEATURE(RBD_FEATURE_LAYERING);
+
+  librbd::ImageCtx *ictx;
+  ASSERT_EQ(0, open_image(m_image_name, &ictx));
+
+  librbd::NoOpProgressContext no_op;
+  ASSERT_EQ(0, ictx->operations->resize(1 << ictx->order, true, no_op));
+
+  bufferlist bl;
+  bl.append(std::string(1 << ictx->order, '1'));
+  ASSERT_EQ((ssize_t)bl.length(),
+            api::Io<>::write(*ictx, 0, bl.length(), bufferlist{bl}, 0));
+  ASSERT_EQ(0, flush_writeback_cache(ictx));
+
+  ASSERT_EQ(0, create_snapshot("snap1", true));
+
+  std::string clone_name = get_temp_image_name();
+  int order = ictx->order;
+  ASSERT_EQ(0, librbd::clone(m_ioctx, m_image_name.c_str(), "snap1", m_ioctx,
+                             clone_name.c_str(), ictx->features, &order, 0, 0));
+
+  TestInternal *parent = this;
+  librbd::ImageCtx *ictx2 = NULL;
+  BOOST_SCOPE_EXIT( (&m_ioctx) (clone_name) (parent) (&ictx2) ) {
+    if (ictx2 != NULL) {
+      ictx2->operations->snap_remove(cls::rbd::UserSnapshotNamespace(),
+				     "snap1");
+      parent->close_image(ictx2);
+    }
+
+    librbd::NoOpProgressContext remove_no_op;
+    ASSERT_EQ(0, librbd::api::Image<>::remove(m_ioctx, clone_name,
+                                              remove_no_op));
+  } BOOST_SCOPE_EXIT_END;
+
+  ASSERT_EQ(0, open_image(clone_name, &ictx2));
+  ASSERT_EQ(0, ictx2->operations->snap_create(cls::rbd::UserSnapshotNamespace(),
+					      "snap1", 0, no_op));
+
+  bufferlist write_full_bl;
+  write_full_bl.append(std::string(1 << ictx2->order, '2'));
+  ASSERT_EQ((ssize_t)write_full_bl.length(),
+            api::Io<>::write(*ictx2, 0, write_full_bl.length(),
+                             bufferlist{write_full_bl}, 0));
+
+  ASSERT_EQ(0, ictx2->operations->flatten(no_op));
+
+  bufferptr read_ptr(bl.length());
+  bufferlist read_bl;
+  read_bl.push_back(read_ptr);
+
+  librbd::io::ReadResult read_result{&read_bl};
+  ASSERT_EQ((ssize_t)read_bl.length(),
+            api::Io<>::read(*ictx2, 0, read_bl.length(),
+                            librbd::io::ReadResult{read_result}, 0));
+  ASSERT_TRUE(write_full_bl.contents_equal(read_bl));
+
+  ASSERT_EQ(0, librbd::api::Image<>::snap_set(ictx2,
+				              cls::rbd::UserSnapshotNamespace(),
+				              "snap1"));
+  ASSERT_EQ((ssize_t)read_bl.length(),
+            api::Io<>::read(*ictx2, 0, read_bl.length(),
+                            librbd::io::ReadResult{read_result}, 0));
+  ASSERT_TRUE(bl.contents_equal(read_bl));
+}
+
+static int iterate_cb(uint64_t off, size_t len, int exists, void *arg)
+{
+  interval_set<uint64_t> *diff = static_cast<interval_set<uint64_t> *>(arg);
+  diff->insert(off, len);
+  return 0;
+}
+
+TEST_F(TestInternal, DiffIterateCloneOverwrite) {
+  REQUIRE_FEATURE(RBD_FEATURE_LAYERING);
+
+  librbd::RBD rbd;
+  librbd::Image image;
+  uint64_t size = 20 << 20;
+  int order = 0;
+
+  ASSERT_EQ(0, rbd.open(m_ioctx, image, m_image_name.c_str(), NULL));
+
+  bufferlist bl;
+  bl.append(std::string(4096, '1'));
+  ASSERT_EQ(4096, image.write(0, 4096, bl));
+
+  interval_set<uint64_t> one;
+  ASSERT_EQ(0, image.diff_iterate2(NULL, 0, size, false, false, iterate_cb,
+                                   (void *)&one));
+  ASSERT_EQ(0, image.snap_create("one"));
+  ASSERT_EQ(0, image.snap_protect("one"));
+
+  std::string clone_name = this->get_temp_image_name();
+  ASSERT_EQ(0, rbd.clone(m_ioctx, m_image_name.c_str(), "one", m_ioctx,
+                         clone_name.c_str(), RBD_FEATURE_LAYERING, &order));
+
+  librbd::ImageCtx *ictx;
+  ASSERT_EQ(0, open_image(clone_name, &ictx));
+  ASSERT_EQ(0, snap_create(*ictx, "one"));
+  ASSERT_EQ(0,
+	    ictx->operations->snap_protect(cls::rbd::UserSnapshotNamespace(),
+					   "one"));
+
+  // Simulate a client that doesn't support deep flatten (old librbd / krbd)
+  // which will copy up the full object from the parent
+  std::string oid = ictx->object_prefix + ".0000000000000000";
+  librados::IoCtx io_ctx;
+  io_ctx.dup(m_ioctx);
+  io_ctx.selfmanaged_snap_set_write_ctx(ictx->snapc.seq, ictx->snaps);
+  ASSERT_EQ(0, io_ctx.write(oid, bl, 4096, 4096));
+
+  interval_set<uint64_t> diff;
+  ASSERT_EQ(0, librbd::api::Image<>::snap_set(ictx,
+                                              cls::rbd::UserSnapshotNamespace(),
+                                              "one"));
+  ASSERT_EQ(0, librbd::api::DiffIterate<>::diff_iterate(
+    ictx, cls::rbd::UserSnapshotNamespace(), nullptr, 0, size, true, false,
+    iterate_cb, (void *)&diff));
+  ASSERT_EQ(one, diff);
+}
+
+TEST_F(TestInternal, TestCoR)
+{
+  REQUIRE_FEATURE(RBD_FEATURE_LAYERING);
+
+  std::string config_value;
+  ASSERT_EQ(0, _rados.conf_get("rbd_clone_copy_on_read", config_value));
+  if (config_value == "false") {
+    std::cout << "SKIPPING due to disabled rbd_copy_on_read" << std::endl;
+    return;
+  }
+
+  m_image_name = get_temp_image_name();
+  m_image_size = 4 << 20;
+
+  int order = 12; // smallest object size is 4K
+  uint64_t features;
+  ASSERT_TRUE(::get_features(&features));
+
+  ASSERT_EQ(0, create_image_full_pp(m_rbd, m_ioctx, m_image_name, m_image_size,
+                                    features, false, &order));
+
+  librbd::Image image;
+  ASSERT_EQ(0, m_rbd.open(m_ioctx, image, m_image_name.c_str(), NULL));
+
+  librbd::image_info_t info;
+  ASSERT_EQ(0, image.stat(info, sizeof(info)));
+
+  const int object_num = info.size / info.obj_size;
+  printf("made parent image \"%s\": %ldK (%d * %" PRIu64 "K)\n", m_image_name.c_str(),
+         (unsigned long)m_image_size, object_num, info.obj_size/1024);
+
+  // write something into parent
+  char test_data[TEST_IO_SIZE + 1];
+  for (int i = 0; i < TEST_IO_SIZE; ++i) {
+    test_data[i] = (char) (rand() % (126 - 33) + 33);
+  }
+  test_data[TEST_IO_SIZE] = '\0';
+
+  // generate a random map which covers every objects with random
+  // offset
+  map<uint64_t, uint64_t> write_tracker;
+  generate_random_iomap(image, object_num, info.obj_size, 100, write_tracker);
+
+  printf("generated random write map:\n");
+  for (map<uint64_t, uint64_t>::iterator itr = write_tracker.begin();
+       itr != write_tracker.end(); ++itr)
+    printf("\t [%-8lu, %-8lu]\n",
+           (unsigned long)itr->first, (unsigned long)itr->second);
+
+  bufferlist bl;
+  bl.append(test_data, TEST_IO_SIZE);
+
+  printf("write data based on random map\n");
+  for (map<uint64_t, uint64_t>::iterator itr = write_tracker.begin();
+       itr != write_tracker.end(); ++itr) {
+    printf("\twrite object-%-4lu\t\n", (unsigned long)itr->first);
+    ASSERT_EQ(TEST_IO_SIZE, image.write(itr->second, TEST_IO_SIZE, bl));
+  }
+
+  ASSERT_EQ(0, image.flush());
+
+  bufferlist readbl;
+  printf("verify written data by reading\n");
+  {
+    map<uint64_t, uint64_t>::iterator itr = write_tracker.begin();
+    printf("\tread object-%-4lu\n", (unsigned long)itr->first);
+    ASSERT_EQ(TEST_IO_SIZE, image.read(itr->second, TEST_IO_SIZE, readbl));
+    ASSERT_TRUE(readbl.contents_equal(bl));
+  }
+
+  int64_t data_pool_id = image.get_data_pool_id();
+  rados_ioctx_t d_ioctx;
+  ASSERT_EQ(0, rados_wait_for_latest_osdmap(_cluster));
+  ASSERT_EQ(0, rados_ioctx_create2(_cluster, data_pool_id, &d_ioctx));
+
+  std::string block_name_prefix = image.get_block_name_prefix() + ".";
+
+  const char *entry;
+  rados_list_ctx_t list_ctx;
+  set<string> obj_checker;
+  ASSERT_EQ(0, rados_nobjects_list_open(d_ioctx, &list_ctx));
+  while (rados_nobjects_list_next(list_ctx, &entry, NULL, NULL) != -ENOENT) {
+    if (boost::starts_with(entry, block_name_prefix)) {
+      const char *block_name_suffix = entry + block_name_prefix.length();
+      obj_checker.insert(block_name_suffix);
+    }
+  }
+  rados_nobjects_list_close(list_ctx);
+
+  std::string snapname = "snap";
+  std::string clonename = get_temp_image_name();
+  ASSERT_EQ(0, image.snap_create(snapname.c_str()));
+  ASSERT_EQ(0, image.close());
+  ASSERT_EQ(0, m_rbd.open(m_ioctx, image, m_image_name.c_str(), snapname.c_str()));
+  ASSERT_EQ(0, image.snap_protect(snapname.c_str()));
+  printf("made snapshot \"%s@parent_snap\" and protect it\n", m_image_name.c_str());
+
+  ASSERT_EQ(0, clone_image_pp(m_rbd, image, m_ioctx, m_image_name.c_str(), snapname.c_str(),
+                              m_ioctx, clonename.c_str(), features));
+  ASSERT_EQ(0, image.close());
+  ASSERT_EQ(0, m_rbd.open(m_ioctx, image, clonename.c_str(), NULL));
+  printf("made and opened clone \"%s\"\n", clonename.c_str());
+
+  printf("read from \"child\"\n");
+  {
+    map<uint64_t, uint64_t>::iterator itr = write_tracker.begin();
+    printf("\tread object-%-4lu\n", (unsigned long)itr->first);
+    ASSERT_EQ(TEST_IO_SIZE, image.read(itr->second, TEST_IO_SIZE, readbl));
+    ASSERT_TRUE(readbl.contents_equal(bl));
+  }
+
+  for (map<uint64_t, uint64_t>::iterator itr = write_tracker.begin();
+       itr != write_tracker.end(); ++itr) {
+    printf("\tread object-%-4lu\n", (unsigned long)itr->first);
+    ASSERT_EQ(TEST_IO_SIZE, image.read(itr->second, TEST_IO_SIZE, readbl));
+    ASSERT_TRUE(readbl.contents_equal(bl));
+  }
+
+  printf("read again reversely\n");
+  for (map<uint64_t, uint64_t>::iterator itr = --write_tracker.end();
+       itr != write_tracker.begin(); --itr) {
+    printf("\tread object-%-4lu\n", (unsigned long)itr->first);
+    ASSERT_EQ(TEST_IO_SIZE, image.read(itr->second, TEST_IO_SIZE, readbl));
+    ASSERT_TRUE(readbl.contents_equal(bl));
+  }
+
+  // close child to flush all copy-on-read
+  ASSERT_EQ(0, image.close());
+
+  printf("check whether child image has the same set of objects as parent\n");
+  ASSERT_EQ(0, m_rbd.open(m_ioctx, image, clonename.c_str(), NULL));
+  block_name_prefix = image.get_block_name_prefix() + ".";
+
+  ASSERT_EQ(0, rados_nobjects_list_open(d_ioctx, &list_ctx));
+  while (rados_nobjects_list_next(list_ctx, &entry, NULL, NULL) != -ENOENT) {
+    if (boost::starts_with(entry, block_name_prefix)) {
+      const char *block_name_suffix = entry + block_name_prefix.length();
+      set<string>::iterator it = obj_checker.find(block_name_suffix);
+      ASSERT_TRUE(it != obj_checker.end());
+      obj_checker.erase(it);
+    }
+  }
+  rados_nobjects_list_close(list_ctx);
+  ASSERT_TRUE(obj_checker.empty());
+  ASSERT_EQ(0, image.close());
+
+  rados_ioctx_destroy(d_ioctx);
+}
+
+TEST_F(TestInternal, FlattenNoEmptyObjects)
+{
+  REQUIRE_FEATURE(RBD_FEATURE_LAYERING);
+
+  m_image_name = get_temp_image_name();
+  m_image_size = 4 << 20;
+
+  int order = 12; // smallest object size is 4K
+  uint64_t features;
+  ASSERT_TRUE(::get_features(&features));
+
+  ASSERT_EQ(0, create_image_full_pp(m_rbd, m_ioctx, m_image_name, m_image_size,
+                                    features, false, &order));
+
+  librbd::Image image;
+  ASSERT_EQ(0, m_rbd.open(m_ioctx, image, m_image_name.c_str(), NULL));
+
+  librbd::image_info_t info;
+  ASSERT_EQ(0, image.stat(info, sizeof(info)));
+
+  const int object_num = info.size / info.obj_size;
+  printf("made parent image \"%s\": %" PRIu64 "K (%d * %" PRIu64 "K)\n",
+	 m_image_name.c_str(), m_image_size, object_num, info.obj_size/1024);
+
+  // write something into parent
+  char test_data[TEST_IO_SIZE + 1];
+  for (int i = 0; i < TEST_IO_SIZE; ++i) {
+    test_data[i] = (char) (rand() % (126 - 33) + 33);
+  }
+  test_data[TEST_IO_SIZE] = '\0';
+
+  // generate a random map which covers every objects with random
+  // offset
+  map<uint64_t, uint64_t> write_tracker;
+  generate_random_iomap(image, object_num, info.obj_size, 100, write_tracker);
+
+  printf("generated random write map:\n");
+  for (map<uint64_t, uint64_t>::iterator itr = write_tracker.begin();
+       itr != write_tracker.end(); ++itr)
+    printf("\t [%-8lu, %-8lu]\n",
+           (unsigned long)itr->first, (unsigned long)itr->second);
+
+  bufferlist bl;
+  bl.append(test_data, TEST_IO_SIZE);
+
+  printf("write data based on random map\n");
+  for (map<uint64_t, uint64_t>::iterator itr = write_tracker.begin();
+       itr != write_tracker.end(); ++itr) {
+    printf("\twrite object-%-4lu\t\n", (unsigned long)itr->first);
+    ASSERT_EQ(TEST_IO_SIZE, image.write(itr->second, TEST_IO_SIZE, bl));
+  }
+
+  ASSERT_EQ(0, image.close());
+  ASSERT_EQ(0, m_rbd.open(m_ioctx, image, m_image_name.c_str(), NULL));
+
+  bufferlist readbl;
+  printf("verify written data by reading\n");
+  {
+    map<uint64_t, uint64_t>::iterator itr = write_tracker.begin();
+    printf("\tread object-%-4lu\n", (unsigned long)itr->first);
+    ASSERT_EQ(TEST_IO_SIZE, image.read(itr->second, TEST_IO_SIZE, readbl));
+    ASSERT_TRUE(readbl.contents_equal(bl));
+  }
+
+  int64_t data_pool_id = image.get_data_pool_id();
+  rados_ioctx_t d_ioctx;
+  ASSERT_EQ(0, rados_wait_for_latest_osdmap(_cluster));
+  ASSERT_EQ(0, rados_ioctx_create2(_cluster, data_pool_id, &d_ioctx));
+
+  std::string block_name_prefix = image.get_block_name_prefix() + ".";
+
+  const char *entry;
+  rados_list_ctx_t list_ctx;
+  set<string> obj_checker;
+  ASSERT_EQ(0, rados_nobjects_list_open(d_ioctx, &list_ctx));
+  while (rados_nobjects_list_next(list_ctx, &entry, NULL, NULL) != -ENOENT) {
+    if (boost::starts_with(entry, block_name_prefix)) {
+      const char *block_name_suffix = entry + block_name_prefix.length();
+      obj_checker.insert(block_name_suffix);
+    }
+  }
+  rados_nobjects_list_close(list_ctx);
+
+  std::string snapname = "snap";
+  std::string clonename = get_temp_image_name();
+  ASSERT_EQ(0, image.snap_create(snapname.c_str()));
+  ASSERT_EQ(0, image.close());
+  ASSERT_EQ(0, m_rbd.open(m_ioctx, image, m_image_name.c_str(), snapname.c_str()));
+  ASSERT_EQ(0, image.snap_protect(snapname.c_str()));
+  printf("made snapshot \"%s@parent_snap\" and protect it\n", m_image_name.c_str());
+
+  ASSERT_EQ(0, clone_image_pp(m_rbd, image, m_ioctx, m_image_name.c_str(), snapname.c_str(),
+                              m_ioctx, clonename.c_str(), features));
+  ASSERT_EQ(0, image.close());
+
+  ASSERT_EQ(0, m_rbd.open(m_ioctx, image, clonename.c_str(), NULL));
+  printf("made and opened clone \"%s\"\n", clonename.c_str());
+
+  printf("flattening clone: \"%s\"\n", clonename.c_str());
+  ASSERT_EQ(0, image.flatten());
+
+  printf("check whether child image has the same set of objects as parent\n");
+  block_name_prefix = image.get_block_name_prefix() + ".";
+
+  ASSERT_EQ(0, rados_nobjects_list_open(d_ioctx, &list_ctx));
+  while (rados_nobjects_list_next(list_ctx, &entry, NULL, NULL) != -ENOENT) {
+    if (boost::starts_with(entry, block_name_prefix)) {
+      const char *block_name_suffix = entry + block_name_prefix.length();
+      set<string>::iterator it = obj_checker.find(block_name_suffix);
+      ASSERT_TRUE(it != obj_checker.end());
+      obj_checker.erase(it);
+    }
+  }
+  rados_nobjects_list_close(list_ctx);
+  ASSERT_TRUE(obj_checker.empty());
+  ASSERT_EQ(0, image.close());
+
+  rados_ioctx_destroy(d_ioctx);
+}
+
+TEST_F(TestInternal, PoolMetadataConfApply) {
+  REQUIRE_FORMAT_V2();
+
+  librbd::api::PoolMetadata<>::remove(m_ioctx, "conf_rbd_cache");
+
+  librbd::ImageCtx *ictx;
+  ASSERT_EQ(0, open_image(m_image_name, &ictx));
+
+  bool cache = ictx->cache;
+  std::string rbd_conf_cache = cache ? "true" : "false";
+  std::string new_rbd_conf_cache = !cache ? "true" : "false";
+
+  ASSERT_EQ(0, librbd::api::PoolMetadata<>::set(m_ioctx, "conf_rbd_cache",
+                                                new_rbd_conf_cache));
+  ASSERT_EQ(0, ictx->state->refresh());
+  ASSERT_EQ(!cache, ictx->cache);
+
+  ASSERT_EQ(0, ictx->operations->metadata_set("conf_rbd_cache",
+                                              rbd_conf_cache));
+  ASSERT_EQ(cache, ictx->cache);
+
+  ASSERT_EQ(0, ictx->operations->metadata_remove("conf_rbd_cache"));
+  ASSERT_EQ(!cache, ictx->cache);
+
+  ASSERT_EQ(0, librbd::api::PoolMetadata<>::remove(m_ioctx, "conf_rbd_cache"));
+  ASSERT_EQ(0, ictx->state->refresh());
+  ASSERT_EQ(cache, ictx->cache);
+  close_image(ictx);
+
+  ASSERT_EQ(0, librbd::api::PoolMetadata<>::set(m_ioctx,
+                                                "conf_rbd_default_order",
+                                                "17"));
+  ASSERT_EQ(0, librbd::api::PoolMetadata<>::set(m_ioctx,
+                                                "conf_rbd_journal_order",
+                                                "13"));
+  std::string image_name = get_temp_image_name();
+  int order = 0;
+  uint64_t features;
+  ASSERT_TRUE(::get_features(&features));
+  ASSERT_EQ(0, create_image_full_pp(m_rbd, m_ioctx, image_name, m_image_size,
+                                    features, false, &order));
+
+  ASSERT_EQ(0, open_image(image_name, &ictx));
+  ASSERT_EQ(ictx->order, 17);
+  ASSERT_EQ(ictx->config.get_val<uint64_t>("rbd_journal_order"), 13U);
+
+  if (is_feature_enabled(RBD_FEATURE_JOURNALING)) {
+    uint8_t order;
+    uint8_t splay_width;
+    int64_t pool_id;
+    C_SaferCond cond;
+    cls::journal::client::get_immutable_metadata(m_ioctx, "journal." + ictx->id,
+                                                 &order, &splay_width, &pool_id,
+                                                 &cond);
+    ASSERT_EQ(0, cond.wait());
+    ASSERT_EQ(order, 13);
+    ASSERT_EQ(0, ictx->operations->update_features(RBD_FEATURE_JOURNALING,
+                                                   false));
+    ASSERT_EQ(0, librbd::api::PoolMetadata<>::set(m_ioctx,
+                                                  "conf_rbd_journal_order",
+                                                  "14"));
+    ASSERT_EQ(0, ictx->operations->update_features(RBD_FEATURE_JOURNALING,
+                                                   true));
+    ASSERT_EQ(ictx->config.get_val<uint64_t>("rbd_journal_order"), 14U);
+
+    C_SaferCond cond1;
+    cls::journal::client::get_immutable_metadata(m_ioctx, "journal." + ictx->id,
+                                                 &order, &splay_width, &pool_id,
+                                                 &cond1);
+    ASSERT_EQ(0, cond1.wait());
+    ASSERT_EQ(order, 14);
+  }
+
+  ASSERT_EQ(0, librbd::api::PoolMetadata<>::remove(m_ioctx,
+                                                   "conf_rbd_default_order"));
+  ASSERT_EQ(0, librbd::api::PoolMetadata<>::remove(m_ioctx,
+                                                   "conf_rbd_journal_order"));
+}
+
+TEST_F(TestInternal, Sparsify) {
+  librbd::ImageCtx *ictx;
+  ASSERT_EQ(0, open_image(m_image_name, &ictx));
+
+  bool sparsify_supported = is_sparsify_supported(ictx->data_ctx,
+                                                  ictx->get_object_name(10));
+  bool sparse_read_supported = is_sparse_read_supported(
+      ictx->data_ctx, ictx->get_object_name(10));
+
+  std::cout << "sparsify_supported=" << sparsify_supported << std::endl;
+  std::cout << "sparse_read_supported=" << sparse_read_supported << std::endl;
+
+  librbd::NoOpProgressContext no_op;
+  ASSERT_EQ(0, ictx->operations->resize((1 << ictx->order) * 20, true, no_op));
+
+  bufferlist bl;
+  bl.append(std::string(4096, '\0'));
+
+  ASSERT_EQ((ssize_t)bl.length(),
+            api::Io<>::write(*ictx, 0, bl.length(), bufferlist{bl}, 0));
+
+  ASSERT_EQ((ssize_t)bl.length(),
+            api::Io<>::write(*ictx, (1 << ictx->order) * 1 + 512,
+                             bl.length(), bufferlist{bl}, 0));
+
+  bl.append(std::string(4096, '1'));
+  bl.append(std::string(4096, '\0'));
+  bl.append(std::string(4096, '2'));
+  bl.append(std::string(4096 - 1, '\0'));
+  ASSERT_EQ((ssize_t)bl.length(),
+            api::Io<>::write(*ictx, (1 << ictx->order) * 10, bl.length(),
+                             bufferlist{bl}, 0));
+
+  bufferlist bl2;
+  bl2.append(std::string(4096 - 1, '\0'));
+  ASSERT_EQ((ssize_t)bl2.length(),
+            api::Io<>::write(*ictx, (1 << ictx->order) * 10 + 4096 * 10,
+                             bl2.length(), bufferlist{bl2}, 0));
+
+  ASSERT_EQ(0, flush_writeback_cache(ictx));
+
+  ASSERT_EQ(0, ictx->operations->sparsify(4096, no_op));
+
+  bufferptr read_ptr(bl.length());
+  bufferlist read_bl;
+  read_bl.push_back(read_ptr);
+
+  librbd::io::ReadResult read_result{&read_bl};
+  ASSERT_EQ((ssize_t)read_bl.length(),
+            api::Io<>::read(*ictx, (1 << ictx->order) * 10, read_bl.length(),
+                            librbd::io::ReadResult{read_result}, 0));
+  ASSERT_TRUE(bl.contents_equal(read_bl));
+
+  std::string oid = ictx->get_object_name(0);
+  uint64_t size;
+  ASSERT_EQ(-ENOENT, ictx->data_ctx.stat(oid, &size, NULL));
+
+  oid = ictx->get_object_name(1);
+  ASSERT_EQ(-ENOENT, ictx->data_ctx.stat(oid, &size, NULL));
+
+  oid = ictx->get_object_name(10);
+  std::map<uint64_t, uint64_t> m;
+  std::map<uint64_t, uint64_t> expected_m;
+  auto read_len = bl.length();
+  bl.clear();
+  if (sparsify_supported && sparse_read_supported) {
+    expected_m = {{4096 * 1, 4096}, {4096 * 3, 4096}};
+    bl.append(std::string(4096, '1'));
+    bl.append(std::string(4096, '2'));
+  } else {
+    expected_m = {{0, 4096 * 4}};
+    bl.append(std::string(4096, '\0'));
+    bl.append(std::string(4096, '1'));
+    bl.append(std::string(4096, '\0'));
+    bl.append(std::string(4096, '2'));
+  }
+  read_bl.clear();
+  EXPECT_EQ(static_cast<int>(expected_m.size()),
+            ictx->data_ctx.sparse_read(oid, m, read_bl, read_len, 0));
+  EXPECT_EQ(m, expected_m);
+  EXPECT_TRUE(bl.contents_equal(read_bl));
+}
+
+
+TEST_F(TestInternal, SparsifyClone) {
+  REQUIRE_FEATURE(RBD_FEATURE_LAYERING);
+
+  librbd::ImageCtx *ictx;
+  ASSERT_EQ(0, open_image(m_image_name, &ictx));
+
+  bool sparsify_supported = is_sparsify_supported(ictx->data_ctx,
+                                                  ictx->get_object_name(10));
+  std::cout << "sparsify_supported=" << sparsify_supported << std::endl;
+
+  librbd::NoOpProgressContext no_op;
+  ASSERT_EQ(0, ictx->operations->resize((1 << ictx->order) * 10, true, no_op));
+
+  ASSERT_EQ(0, create_snapshot("snap", true));
+  std::string clone_name = get_temp_image_name();
+  int order = ictx->order;
+  ASSERT_EQ(0, librbd::clone(m_ioctx, m_image_name.c_str(), "snap", m_ioctx,
+                             clone_name.c_str(), ictx->features, &order, 0, 0));
+  close_image(ictx);
+
+  ASSERT_EQ(0, open_image(clone_name, &ictx));
+
+  BOOST_SCOPE_EXIT_ALL(this, &ictx, clone_name) {
+    close_image(ictx);
+    librbd::NoOpProgressContext no_op;
+    EXPECT_EQ(0, librbd::api::Image<>::remove(m_ioctx, clone_name, no_op));
+  };
+
+  ASSERT_EQ(0, ictx->operations->resize((1 << ictx->order) * 20, true, no_op));
+
+  bufferlist bl;
+  bl.append(std::string(4096, '\0'));
+
+  ASSERT_EQ((ssize_t)bl.length(),
+            api::Io<>::write(*ictx, 0, bl.length(), bufferlist{bl}, 0));
+
+  bl.append(std::string(4096, '1'));
+  bl.append(std::string(4096, '\0'));
+  bl.append(std::string(4096, '2'));
+  bl.append(std::string(4096, '\0'));
+  ASSERT_EQ((ssize_t)bl.length(),
+            api::Io<>::write(*ictx, (1 << ictx->order) * 10, bl.length(),
+                             bufferlist{bl}, 0));
+  ASSERT_EQ(0, flush_writeback_cache(ictx));
+
+  ASSERT_EQ(0, ictx->operations->sparsify(4096, no_op));
+
+  bufferptr read_ptr(bl.length());
+  bufferlist read_bl;
+  read_bl.push_back(read_ptr);
+
+  librbd::io::ReadResult read_result{&read_bl};
+  ASSERT_EQ((ssize_t)read_bl.length(),
+            api::Io<>::read(*ictx, (1 << ictx->order) * 10, read_bl.length(),
+                            librbd::io::ReadResult{read_result}, 0));
+  ASSERT_TRUE(bl.contents_equal(read_bl));
+
+  std::string oid = ictx->get_object_name(0);
+  uint64_t size;
+  ASSERT_EQ(0, ictx->data_ctx.stat(oid, &size, NULL));
+  ASSERT_EQ(0, ictx->data_ctx.read(oid, read_bl, 4096, 0));
+}
+
+TEST_F(TestInternal, MissingDataPool) {
+  REQUIRE_FORMAT_V2();
+
+  librbd::ImageCtx *ictx;
+  ASSERT_EQ(0, open_image(m_image_name, &ictx));
+  ASSERT_EQ(0, snap_create(*ictx, "snap1"));
+  std::string header_oid = ictx->header_oid;
+  close_image(ictx);
+
+  // emulate non-existent data pool
+  int64_t pool_id = 1234;
+  std::string pool_name;
+  int r;
+  while ((r = _rados.pool_reverse_lookup(pool_id, &pool_name)) == 0) {
+    pool_id++;
+  }
+  ASSERT_EQ(r, -ENOENT);
+  bufferlist bl;
+  using ceph::encode;
+  encode(pool_id, bl);
+  ASSERT_EQ(0, m_ioctx.omap_set(header_oid, {{"data_pool_id", bl}}));
+
+  ASSERT_EQ(0, open_image(m_image_name, &ictx));
+
+  ASSERT_FALSE(ictx->data_ctx.is_valid());
+  ASSERT_EQ(pool_id, librbd::api::Image<>::get_data_pool_id(ictx));
+
+  librbd::image_info_t info;
+  ASSERT_EQ(0, librbd::info(ictx, info, sizeof(info)));
+
+  vector<librbd::snap_info_t> snaps;
+  EXPECT_EQ(0, librbd::api::Snapshot<>::list(ictx, snaps));
+  EXPECT_EQ(1U, snaps.size());
+  EXPECT_EQ("snap1", snaps[0].name);
+
+  bufferptr read_ptr(256);
+  bufferlist read_bl;
+  read_bl.push_back(read_ptr);
+  librbd::io::ReadResult read_result{&read_bl};
+  ASSERT_EQ(-ENODEV,
+            api::Io<>::read(*ictx, 0, 256,
+                            librbd::io::ReadResult{read_result}, 0));
+  ASSERT_EQ(-ENODEV,
+            api::Io<>::write(*ictx, 0, bl.length(), bufferlist{bl}, 0));
+  ASSERT_EQ(-ENODEV, api::Io<>::discard(*ictx, 0, 1, 256));
+  ASSERT_EQ(-ENODEV,
+            api::Io<>::write_same(*ictx, 0, bl.length(), bufferlist{bl}, 0));
+  uint64_t mismatch_off;
+  ASSERT_EQ(-ENODEV,
+            api::Io<>::compare_and_write(*ictx, 0, bl.length(),
+                                         bufferlist{bl}, bufferlist{bl},
+                                         &mismatch_off, 0));
+  ASSERT_EQ(-ENODEV, api::Io<>::flush(*ictx));
+
+  ASSERT_EQ(-ENODEV, snap_create(*ictx, "snap2"));
+  ASSERT_EQ(0, ictx->operations->snap_remove(cls::rbd::UserSnapshotNamespace(),
+                                             "snap1"));
+
+  librbd::NoOpProgressContext no_op;
+  ASSERT_EQ(-ENODEV, ictx->operations->resize(0, true, no_op));
+
+  close_image(ictx);
+
+  ASSERT_EQ(0, librbd::api::Image<>::remove(m_ioctx, m_image_name, no_op));
+
+  ASSERT_EQ(0, create_image_pp(m_rbd, m_ioctx, m_image_name, m_image_size));
+}
+
+} // namespace librbd