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

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

6 files changed, 14947 insertions, 0 deletions

diff --git a/src/cls/rbd/cls_rbd.cc b/src/cls/rbd/cls_rbd.cc
new file mode 100644
index 000000000..ebf7994c4
--- /dev/null
+++ b/src/cls/rbd/cls_rbd.cc
@@ -0,0 +1,8645 @@
+// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
+// vim: ts=8 sw=2 smarttab
+
+/** \file
+ *
+ * This is an OSD class that implements methods for
+ * use with rbd.
+ *
+ * Most of these deal with the rbd header object. Methods prefixed
+ * with old_ deal with the original rbd design, in which clients read
+ * and interpreted the header object directly.
+ *
+ * The new format is meant to be opaque to clients - all their
+ * interactions with non-data objects should go through this
+ * class. The OSD class interface leaves the class to implement its
+ * own argument and payload serialization/deserialization, so for ease
+ * of implementation we use the existing ceph encoding/decoding
+ * methods. Something like json might be preferable, but the rbd
+ * kernel module has to be able to understand format as well. The
+ * datatypes exposed to the clients are strings, unsigned integers,
+ * and vectors of those types. The on-wire format can be found in
+ * src/include/encoding.h.
+ *
+ * The methods for interacting with the new format document their
+ * parameters as the client sees them - it would be silly to mention
+ * in each one that they take an input and an output bufferlist.
+ */
+#include "include/types.h"
+
+#include <algorithm>
+#include <errno.h>
+#include <sstream>
+
+#include "include/uuid.h"
+#include "common/bit_vector.hpp"
+#include "common/errno.h"
+#include "objclass/objclass.h"
+#include "osd/osd_types.h"
+#include "include/rbd_types.h"
+#include "include/rbd/object_map_types.h"
+
+#include "cls/rbd/cls_rbd.h"
+#include "cls/rbd/cls_rbd_types.h"
+
+#include <boost/algorithm/string/predicate.hpp>
+
+using std::istringstream;
+using std::ostringstream;
+using std::map;
+using std::set;
+using std::string;
+using std::vector;
+
+using ceph::BitVector;
+using ceph::bufferlist;
+using ceph::bufferptr;
+using ceph::encode;
+using ceph::decode;
+
+/*
+ * Object keys:
+ *
+ * <partial list>
+ *
+ * stripe_unit: size in bytes of the stripe unit.  if not present,
+ *   the stripe unit is assumed to match the object size (1 << order).
+ *
+ * stripe_count: number of objects to stripe over before looping back.
+ *   if not present or 1, striping is disabled.  this is the default.
+ *
+ */
+
+CLS_VER(2,0)
+CLS_NAME(rbd)
+
+#define RBD_MAX_KEYS_READ 64
+#define RBD_SNAP_KEY_PREFIX "snapshot_"
+#define RBD_SNAP_CHILDREN_KEY_PREFIX "snap_children_"
+#define RBD_DIR_ID_KEY_PREFIX "id_"
+#define RBD_DIR_NAME_KEY_PREFIX "name_"
+#define RBD_METADATA_KEY_PREFIX "metadata_"
+
+namespace {
+
+uint64_t get_encode_features(cls_method_context_t hctx) {
+  uint64_t features = 0;
+  ceph_release_t require_osd_release = cls_get_required_osd_release(hctx);
+  if (require_osd_release >= ceph_release_t::nautilus) {
+    features |= CEPH_FEATURE_SERVER_NAUTILUS;
+  }
+  return features;
+}
+
+bool calc_sparse_extent(const bufferptr &bp, size_t sparse_size,
+                        uint64_t length, size_t *write_offset,
+                        size_t *write_length, size_t *offset) {
+  size_t extent_size;
+  if (*offset + sparse_size > length) {
+    extent_size = length - *offset;
+  } else {
+    extent_size = sparse_size;
+  }
+
+  bufferptr extent(bp, *offset, extent_size);
+  *offset += extent_size;
+
+  bool extent_is_zero = extent.is_zero();
+  if (!extent_is_zero) {
+    *write_length += extent_size;
+  }
+  if (extent_is_zero && *write_length == 0) {
+    *write_offset += extent_size;
+  }
+
+  if ((extent_is_zero || *offset == length) && *write_length != 0) {
+    return true;
+  }
+  return false;
+}
+
+} // anonymous namespace
+
+static int snap_read_header(cls_method_context_t hctx, bufferlist& bl)
+{
+  unsigned snap_count = 0;
+  uint64_t snap_names_len = 0;
+  struct rbd_obj_header_ondisk *header;
+
+  CLS_LOG(20, "snapshots_list");
+
+  while (1) {
+    int len = sizeof(*header) +
+      snap_count * sizeof(struct rbd_obj_snap_ondisk) +
+      snap_names_len;
+
+    int rc = cls_cxx_read(hctx, 0, len, &bl);
+    if (rc < 0)
+      return rc;
+
+    if (bl.length() < sizeof(*header))
+      return -EINVAL;
+
+    header = (struct rbd_obj_header_ondisk *)bl.c_str();
+    ceph_assert(header);
+
+    if ((snap_count != header->snap_count) ||
+        (snap_names_len != header->snap_names_len)) {
+      snap_count = header->snap_count;
+      snap_names_len = header->snap_names_len;
+      bl.clear();
+      continue;
+    }
+    break;
+  }
+
+  return 0;
+}
+
+static void key_from_snap_id(snapid_t snap_id, string *out)
+{
+  ostringstream oss;
+  oss << RBD_SNAP_KEY_PREFIX
+      << std::setw(16) << std::setfill('0') << std::hex << snap_id;
+  *out = oss.str();
+}
+
+static snapid_t snap_id_from_key(const string &key) {
+  istringstream iss(key);
+  uint64_t id;
+  iss.ignore(strlen(RBD_SNAP_KEY_PREFIX)) >> std::hex >> id;
+  return id;
+}
+
+template<typename T>
+static int read_key(cls_method_context_t hctx, const string &key, T *out)
+{
+  bufferlist bl;
+  int r = cls_cxx_map_get_val(hctx, key, &bl);
+  if (r < 0) {
+    if (r != -ENOENT) {
+      CLS_ERR("error reading omap key %s: %s", key.c_str(), cpp_strerror(r).c_str());
+    }
+    return r;
+  }
+
+  try {
+    auto it = bl.cbegin();
+    decode(*out, it);
+  } catch (const ceph::buffer::error &err) {
+    CLS_ERR("error decoding %s", key.c_str());
+    return -EIO;
+  }
+
+  return 0;
+}
+
+template <typename T>
+static int write_key(cls_method_context_t hctx, const string &key, const T &t) {
+  bufferlist bl;
+  encode(t, bl);
+
+  int r = cls_cxx_map_set_val(hctx, key, &bl);
+  if (r < 0) {
+    CLS_ERR("failed to set omap key: %s", key.c_str());
+    return r;
+  }
+  return 0;
+}
+
+template <typename T>
+static int write_key(cls_method_context_t hctx, const string &key, const T &t,
+                     uint64_t features) {
+  bufferlist bl;
+  encode(t, bl, features);
+
+  int r = cls_cxx_map_set_val(hctx, key, &bl);
+  if (r < 0) {
+    CLS_ERR("failed to set omap key: %s", key.c_str());
+    return r;
+  }
+  return 0;
+}
+
+static int remove_key(cls_method_context_t hctx, const string &key) {
+  int r = cls_cxx_map_remove_key(hctx, key);
+  if (r < 0 && r != -ENOENT) {
+      CLS_ERR("failed to remove key: %s", key.c_str());
+      return r;
+  }
+  return 0;
+}
+
+static bool is_valid_id(const string &id) {
+  if (!id.size())
+    return false;
+  for (size_t i = 0; i < id.size(); ++i) {
+    if (!isalnum(id[i])) {
+      return false;
+    }
+  }
+  return true;
+}
+
+/**
+ * verify that the header object exists
+ *
+ * @return 0 if the object exists, -ENOENT if it does not, or other error
+ */
+static int check_exists(cls_method_context_t hctx)
+{
+  uint64_t size;
+  time_t mtime;
+  return cls_cxx_stat(hctx, &size, &mtime);
+}
+
+namespace image {
+
+/**
+ * check that given feature(s) are set
+ *
+ * @param hctx context
+ * @param need features needed
+ * @return 0 if features are set, negative error (like ENOEXEC) otherwise
+ */
+int require_feature(cls_method_context_t hctx, uint64_t need)
+{
+  uint64_t features;
+  int r = read_key(hctx, "features", &features);
+  if (r == -ENOENT)   // this implies it's an old-style image with no features
+    return -ENOEXEC;
+  if (r < 0)
+    return r;
+  if ((features & need) != need) {
+    CLS_LOG(10, "require_feature missing feature %llx, have %llx",
+            (unsigned long long)need, (unsigned long long)features);
+    return -ENOEXEC;
+  }
+  return 0;
+}
+
+std::string snap_children_key_from_snap_id(snapid_t snap_id)
+{
+  ostringstream oss;
+  oss << RBD_SNAP_CHILDREN_KEY_PREFIX
+      << std::setw(16) << std::setfill('0') << std::hex << snap_id;
+  return oss.str();
+}
+
+int set_op_features(cls_method_context_t hctx, uint64_t op_features,
+                    uint64_t mask) {
+  uint64_t orig_features;
+  int r = read_key(hctx, "features", &orig_features);
+  if (r < 0) {
+    CLS_ERR("failed to read features off disk: %s", cpp_strerror(r).c_str());
+    return r;
+  }
+
+  uint64_t orig_op_features = 0;
+  r = read_key(hctx, "op_features", &orig_op_features);
+  if (r < 0 && r != -ENOENT) {
+    CLS_ERR("Could not read op features off disk: %s", cpp_strerror(r).c_str());
+    return r;
+  }
+
+  op_features = (orig_op_features & ~mask) | (op_features & mask);
+  CLS_LOG(10, "op_features=%" PRIu64 " orig_op_features=%" PRIu64,
+          op_features, orig_op_features);
+  if (op_features == orig_op_features) {
+    return 0;
+  }
+
+  uint64_t features = orig_features;
+  if (op_features == 0ULL) {
+    features &= ~RBD_FEATURE_OPERATIONS;
+
+    r = cls_cxx_map_remove_key(hctx, "op_features");
+    if (r == -ENOENT) {
+      r = 0;
+    }
+  } else {
+    features |= RBD_FEATURE_OPERATIONS;
+
+    bufferlist bl;
+    encode(op_features, bl);
+    r = cls_cxx_map_set_val(hctx, "op_features", &bl);
+  }
+
+  if (r < 0) {
+    CLS_ERR("error updating op features: %s", cpp_strerror(r).c_str());
+    return r;
+  }
+
+  if (features != orig_features) {
+    bufferlist bl;
+    encode(features, bl);
+    r = cls_cxx_map_set_val(hctx, "features", &bl);
+    if (r < 0) {
+      CLS_ERR("error updating features: %s", cpp_strerror(r).c_str());
+      return r;
+    }
+  }
+
+  return 0;
+}
+
+int set_migration(cls_method_context_t hctx,
+                  const cls::rbd::MigrationSpec &migration_spec, bool init) {
+  if (init) {
+    bufferlist bl;
+    int r = cls_cxx_map_get_val(hctx, "migration", &bl);
+    if (r != -ENOENT) {
+      if (r == 0) {
+        CLS_LOG(10, "migration already set");
+        return -EEXIST;
+      }
+      CLS_ERR("failed to read migration off disk: %s", cpp_strerror(r).c_str());
+      return r;
+    }
+
+    uint64_t features = 0;
+    r = read_key(hctx, "features", &features);
+    if (r == -ENOENT) {
+      CLS_LOG(20, "no features, assuming v1 format");
+      bufferlist header;
+      r = cls_cxx_read(hctx, 0, sizeof(RBD_HEADER_TEXT), &header);
+      if (r < 0) {
+        CLS_ERR("failed to read v1 header: %s", cpp_strerror(r).c_str());
+        return r;
+      }
+      if (header.length() != sizeof(RBD_HEADER_TEXT)) {
+        CLS_ERR("unrecognized v1 header format");
+        return -ENXIO;
+      }
+      if (memcmp(RBD_HEADER_TEXT, header.c_str(), header.length()) != 0) {
+        if (memcmp(RBD_MIGRATE_HEADER_TEXT, header.c_str(),
+                   header.length()) == 0) {
+          CLS_LOG(10, "migration already set");
+          return -EEXIST;
+        } else {
+          CLS_ERR("unrecognized v1 header format");
+          return -ENXIO;
+        }
+      }
+      if (migration_spec.header_type != cls::rbd::MIGRATION_HEADER_TYPE_SRC) {
+        CLS_LOG(10, "v1 format image can only be migration source");
+        return -EINVAL;
+      }
+
+      header.clear();
+      header.append(RBD_MIGRATE_HEADER_TEXT);
+      r = cls_cxx_write(hctx, 0, header.length(), &header);
+      if (r < 0) {
+        CLS_ERR("error updating v1 header: %s", cpp_strerror(r).c_str());
+        return r;
+      }
+    } else if (r < 0) {
+      CLS_ERR("failed to read features off disk: %s", cpp_strerror(r).c_str());
+      return r;
+    } else if ((features & RBD_FEATURE_MIGRATING) != 0ULL) {
+      if (migration_spec.header_type != cls::rbd::MIGRATION_HEADER_TYPE_DST) {
+        CLS_LOG(10, "migrating feature already set");
+        return -EEXIST;
+      }
+    } else {
+      features |= RBD_FEATURE_MIGRATING;
+      bl.clear();
+      encode(features, bl);
+      r = cls_cxx_map_set_val(hctx, "features", &bl);
+      if (r < 0) {
+        CLS_ERR("error updating features: %s", cpp_strerror(r).c_str());
+        return r;
+      }
+    }
+  }
+
+  bufferlist bl;
+  encode(migration_spec, bl);
+  int r = cls_cxx_map_set_val(hctx, "migration", &bl);
+  if (r < 0) {
+    CLS_ERR("error setting migration: %s", cpp_strerror(r).c_str());
+    return r;
+  }
+
+  return 0;
+}
+
+int read_migration(cls_method_context_t hctx,
+                   cls::rbd::MigrationSpec *migration_spec) {
+  uint64_t features = 0;
+  int r = read_key(hctx, "features", &features);
+  if (r == -ENOENT) {
+    CLS_LOG(20, "no features, assuming v1 format");
+    bufferlist header;
+    r = cls_cxx_read(hctx, 0, sizeof(RBD_HEADER_TEXT), &header);
+    if (r < 0) {
+      CLS_ERR("failed to read v1 header: %s", cpp_strerror(r).c_str());
+      return r;
+    }
+    if (header.length() != sizeof(RBD_HEADER_TEXT)) {
+      CLS_ERR("unrecognized v1 header format");
+      return -ENXIO;
+    }
+    if (memcmp(RBD_MIGRATE_HEADER_TEXT, header.c_str(), header.length()) != 0) {
+      if (memcmp(RBD_HEADER_TEXT, header.c_str(), header.length()) == 0) {
+        CLS_LOG(10, "migration feature not set");
+        return -EINVAL;
+      } else {
+        CLS_ERR("unrecognized v1 header format");
+        return -ENXIO;
+      }
+    }
+    if (migration_spec->header_type != cls::rbd::MIGRATION_HEADER_TYPE_SRC) {
+      CLS_LOG(10, "v1 format image can only be migration source");
+      return -EINVAL;
+    }
+  } else if (r < 0) {
+    CLS_ERR("failed to read features off disk: %s", cpp_strerror(r).c_str());
+    return r;
+  } else if ((features & RBD_FEATURE_MIGRATING) == 0ULL) {
+    CLS_LOG(10, "migration feature not set");
+    return -EINVAL;
+  }
+
+  r = read_key(hctx, "migration", migration_spec);
+  if (r < 0) {
+    CLS_ERR("failed to read migration off disk: %s", cpp_strerror(r).c_str());
+    return r;
+  }
+
+  return 0;
+}
+
+int remove_migration(cls_method_context_t hctx) {
+  int r = remove_key(hctx, "migration");
+  if (r < 0) {
+    return r;
+  }
+
+  uint64_t features = 0;
+  r = read_key(hctx, "features", &features);
+  if (r == -ENOENT) {
+    CLS_LOG(20, "no features, assuming v1 format");
+    bufferlist header;
+    r = cls_cxx_read(hctx, 0, sizeof(RBD_MIGRATE_HEADER_TEXT), &header);
+    if (header.length() != sizeof(RBD_MIGRATE_HEADER_TEXT)) {
+      CLS_ERR("unrecognized v1 header format");
+      return -ENXIO;
+    }
+    if (memcmp(RBD_MIGRATE_HEADER_TEXT, header.c_str(), header.length()) != 0) {
+      if (memcmp(RBD_HEADER_TEXT, header.c_str(), header.length()) == 0) {
+        CLS_LOG(10, "migration feature not set");
+        return -EINVAL;
+      } else {
+        CLS_ERR("unrecognized v1 header format");
+        return -ENXIO;
+      }
+    }
+    header.clear();
+    header.append(RBD_HEADER_TEXT);
+    r = cls_cxx_write(hctx, 0, header.length(), &header);
+    if (r < 0) {
+      CLS_ERR("error updating v1 header: %s", cpp_strerror(r).c_str());
+      return r;
+    }
+  } else if (r < 0) {
+    CLS_ERR("failed to read features off disk: %s", cpp_strerror(r).c_str());
+    return r;
+  } else if ((features & RBD_FEATURE_MIGRATING) == 0ULL) {
+    CLS_LOG(10, "migrating feature not set");
+  } else {
+    features &= ~RBD_FEATURE_MIGRATING;
+    bufferlist bl;
+    encode(features, bl);
+    r = cls_cxx_map_set_val(hctx, "features", &bl);
+    if (r < 0) {
+      CLS_ERR("error updating features: %s", cpp_strerror(r).c_str());
+      return r;
+    }
+  }
+
+  return 0;
+}
+
+namespace snapshot {
+
+template<typename L>
+int iterate(cls_method_context_t hctx, L& lambda) {
+  int max_read = RBD_MAX_KEYS_READ;
+  string last_read = RBD_SNAP_KEY_PREFIX;
+  bool more = false;
+  do {
+    map<string, bufferlist> vals;
+    int r = cls_cxx_map_get_vals(hctx, last_read, RBD_SNAP_KEY_PREFIX,
+			         max_read, &vals, &more);
+    if (r < 0) {
+      return r;
+    }
+
+    cls_rbd_snap snap_meta;
+    for (auto& val : vals) {
+      auto iter = val.second.cbegin();
+      try {
+	decode(snap_meta, iter);
+      } catch (const ceph::buffer::error &err) {
+	CLS_ERR("error decoding snapshot metadata for snap : %s",
+	        val.first.c_str());
+	return -EIO;
+      }
+
+      r = lambda(snap_meta);
+      if (r < 0) {
+        return r;
+      }
+    }
+
+    if (!vals.empty()) {
+      last_read = vals.rbegin()->first;
+    }
+  } while (more);
+
+  return 0;
+}
+
+int write(cls_method_context_t hctx, const std::string& snap_key,
+          cls_rbd_snap&& snap) {
+  int r;
+  uint64_t encode_features = get_encode_features(hctx);
+  if (snap.migrate_parent_format(encode_features)) {
+    // ensure the normalized parent link exists before removing it from the
+    // snapshot record
+    cls_rbd_parent on_disk_parent;
+    r = read_key(hctx, "parent", &on_disk_parent);
+    if (r < 0 && r != -ENOENT) {
+      return r;
+    }
+
+    if (!on_disk_parent.exists()) {
+      on_disk_parent = snap.parent;
+      on_disk_parent.head_overlap = std::nullopt;
+
+      r = write_key(hctx, "parent", on_disk_parent, encode_features);
+      if (r < 0) {
+        return r;
+      }
+    }
+
+    // only store the parent overlap in the snapshot
+    snap.parent_overlap = snap.parent.head_overlap;
+    snap.parent = {};
+  }
+
+  r = write_key(hctx, snap_key, snap, encode_features);
+  if (r < 0) {
+    return r;
+  }
+  return 0;
+}
+
+} // namespace snapshot
+
+namespace parent {
+
+int attach(cls_method_context_t hctx, cls_rbd_parent parent,
+           bool reattach) {
+  int r = check_exists(hctx);
+  if (r < 0) {
+    CLS_LOG(20, "cls_rbd::image::parent::attach: child doesn't exist");
+    return r;
+  }
+
+  r = image::require_feature(hctx, RBD_FEATURE_LAYERING);
+  if (r < 0) {
+    CLS_LOG(20, "cls_rbd::image::parent::attach: child does not support "
+                "layering");
+    return r;
+  }
+
+  CLS_LOG(20, "cls_rbd::image::parent::attach: pool=%" PRIi64 ", ns=%s, id=%s, "
+              "snapid=%" PRIu64 ", size=%" PRIu64,
+          parent.pool_id, parent.pool_namespace.c_str(),
+          parent.image_id.c_str(), parent.snap_id.val,
+          parent.head_overlap.value_or(0ULL));
+  if (!parent.exists() || parent.head_overlap.value_or(0ULL) == 0ULL) {
+    return -EINVAL;
+  }
+
+  // make sure there isn't already a parent
+  cls_rbd_parent on_disk_parent;
+  r = read_key(hctx, "parent", &on_disk_parent);
+  if (r < 0 && r != -ENOENT) {
+    return r;
+  }
+
+  auto on_disk_parent_without_overlap{on_disk_parent};
+  on_disk_parent_without_overlap.head_overlap = parent.head_overlap;
+
+  if (r == 0 &&
+      (on_disk_parent.head_overlap ||
+       on_disk_parent_without_overlap != parent) &&
+      !reattach) {
+    CLS_LOG(20, "cls_rbd::parent::attach: existing legacy parent "
+                "pool=%" PRIi64 ", ns=%s, id=%s, snapid=%" PRIu64 ", "
+                "overlap=%" PRIu64,
+            on_disk_parent.pool_id, on_disk_parent.pool_namespace.c_str(),
+            on_disk_parent.image_id.c_str(), on_disk_parent.snap_id.val,
+            on_disk_parent.head_overlap.value_or(0ULL));
+    return -EEXIST;
+  }
+
+  // our overlap is the min of our size and the parent's size.
+  uint64_t our_size;
+  r = read_key(hctx, "size", &our_size);
+  if (r < 0) {
+    return r;
+  }
+
+  parent.head_overlap = std::min(*parent.head_overlap, our_size);
+
+  r = write_key(hctx, "parent", parent, get_encode_features(hctx));
+  if (r < 0) {
+    return r;
+  }
+
+  return 0;
+}
+
+int detach(cls_method_context_t hctx, bool legacy_api) {
+  int r = check_exists(hctx);
+  if (r < 0) {
+    CLS_LOG(20, "cls_rbd::parent::detach: child doesn't exist");
+    return r;
+  }
+
+  uint64_t features;
+  r = read_key(hctx, "features", &features);
+  if (r == -ENOENT || ((features & RBD_FEATURE_LAYERING) == 0)) {
+    CLS_LOG(20, "cls_rbd::image::parent::detach: child does not support "
+                "layering");
+    return -ENOEXEC;
+  } else if (r < 0) {
+    return r;
+  }
+
+  cls_rbd_parent on_disk_parent;
+  r = read_key(hctx, "parent", &on_disk_parent);
+  if (r < 0) {
+    return r;
+  } else if (legacy_api && !on_disk_parent.pool_namespace.empty()) {
+    return -EXDEV;
+  } else if (!on_disk_parent.head_overlap) {
+    return -ENOENT;
+  }
+
+  auto detach_lambda = [hctx, features](const cls_rbd_snap& snap_meta) {
+    if (snap_meta.parent.pool_id != -1 || snap_meta.parent_overlap) {
+      if ((features & RBD_FEATURE_DEEP_FLATTEN) != 0ULL) {
+        // remove parent reference from snapshot
+        cls_rbd_snap snap_meta_copy = snap_meta;
+        snap_meta_copy.parent = {};
+        snap_meta_copy.parent_overlap = std::nullopt;
+
+        std::string snap_key;
+        key_from_snap_id(snap_meta_copy.id, &snap_key);
+        int r = snapshot::write(hctx, snap_key, std::move(snap_meta_copy));
+        if (r < 0) {
+          return r;
+        }
+      } else {
+        return -EEXIST;
+      }
+    }
+    return 0;
+  };
+
+  r = snapshot::iterate(hctx, detach_lambda);
+  bool has_child_snaps = (r == -EEXIST);
+  if (r < 0 && r != -EEXIST) {
+    return r;
+  }
+
+  ceph_release_t require_osd_release = cls_get_required_osd_release(hctx);
+  if (has_child_snaps && require_osd_release >= ceph_release_t::nautilus) {
+    // remove overlap from HEAD revision but keep spec for snapshots
+    on_disk_parent.head_overlap = std::nullopt;
+    r = write_key(hctx, "parent", on_disk_parent, get_encode_features(hctx));
+    if (r < 0) {
+      return r;
+    }
+  } else {
+    r = remove_key(hctx, "parent");
+    if (r < 0 && r != -ENOENT) {
+      return r;
+    }
+  }
+
+  if (!has_child_snaps) {
+    // disable clone child op feature if no longer associated
+    r = set_op_features(hctx, 0, RBD_OPERATION_FEATURE_CLONE_CHILD);
+    if (r < 0) {
+      return r;
+    }
+  }
+  return 0;
+}
+
+} // namespace parent
+} // namespace image
+
+/**
+ * Initialize the header with basic metadata.
+ * Extra features may initialize more fields in the future.
+ * Everything is stored as key/value pairs as omaps in the header object.
+ *
+ * If features the OSD does not understand are requested, -ENOSYS is
+ * returned.
+ *
+ * Input:
+ * @param size number of bytes in the image (uint64_t)
+ * @param order bits to shift to determine the size of data objects (uint8_t)
+ * @param features what optional things this image will use (uint64_t)
+ * @param object_prefix a prefix for all the data objects
+ * @param data_pool_id pool id where data objects is stored (int64_t)
+ *
+ * Output:
+ * @return 0 on success, negative error code on failure
+ */
+int create(cls_method_context_t hctx, bufferlist *in, bufferlist *out)
+{
+  string object_prefix;
+  uint64_t features, size;
+  uint8_t order;
+  int64_t data_pool_id = -1;
+
+  try {
+    auto iter = in->cbegin();
+    decode(size, iter);
+    decode(order, iter);
+    decode(features, iter);
+    decode(object_prefix, iter);
+    if (!iter.end()) {
+      decode(data_pool_id, iter);
+    }
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+
+  CLS_LOG(20, "create object_prefix=%s size=%llu order=%u features=%llu",
+	  object_prefix.c_str(), (unsigned long long)size, order,
+	  (unsigned long long)features);
+
+  if (features & ~RBD_FEATURES_ALL) {
+    return -ENOSYS;
+  }
+
+  if (!object_prefix.size()) {
+    return -EINVAL;
+  }
+
+  bufferlist stored_prefixbl;
+  int r = cls_cxx_map_get_val(hctx, "object_prefix", &stored_prefixbl);
+  if (r != -ENOENT) {
+    CLS_ERR("reading object_prefix returned %d", r);
+    return -EEXIST;
+  }
+
+  bufferlist sizebl;
+  bufferlist orderbl;
+  bufferlist featuresbl;
+  bufferlist object_prefixbl;
+  bufferlist snap_seqbl;
+  bufferlist timestampbl;
+  uint64_t snap_seq = 0;
+  utime_t timestamp = ceph_clock_now();
+  encode(size, sizebl);
+  encode(order, orderbl);
+  encode(features, featuresbl);
+  encode(object_prefix, object_prefixbl);
+  encode(snap_seq, snap_seqbl);
+  encode(timestamp, timestampbl);
+
+  map<string, bufferlist> omap_vals;
+  omap_vals["size"] = sizebl;
+  omap_vals["order"] = orderbl;
+  omap_vals["features"] = featuresbl;
+  omap_vals["object_prefix"] = object_prefixbl;
+  omap_vals["snap_seq"] = snap_seqbl;
+  omap_vals["create_timestamp"] = timestampbl;
+  omap_vals["access_timestamp"] = timestampbl;
+  omap_vals["modify_timestamp"] = timestampbl;
+
+  if ((features & RBD_FEATURE_OPERATIONS) != 0ULL) {
+    CLS_ERR("Attempting to set internal feature: operations");
+    return -EINVAL;
+  }
+
+  if (features & RBD_FEATURE_DATA_POOL) {
+    if (data_pool_id == -1) {
+      CLS_ERR("data pool not provided with feature enabled");
+      return -EINVAL;
+    }
+
+    bufferlist data_pool_id_bl;
+    encode(data_pool_id, data_pool_id_bl);
+    omap_vals["data_pool_id"] = data_pool_id_bl;
+  } else if (data_pool_id != -1) {
+    CLS_ERR("data pool provided with feature disabled");
+    return -EINVAL;
+  }
+
+  r = cls_cxx_map_set_vals(hctx, &omap_vals);
+  if (r < 0)
+    return r;
+
+  return 0;
+}
+
+/**
+ * Input:
+ * @param snap_id which snapshot to query, or CEPH_NOSNAP (uint64_t) (deprecated)
+ * @param read_only true if the image will be used read-only (bool)
+ *
+ * Output:
+ * @param features list of enabled features for the given snapshot (uint64_t)
+ * @param incompatible incompatible feature bits
+ * @returns 0 on success, negative error code on failure
+ */
+int get_features(cls_method_context_t hctx, bufferlist *in, bufferlist *out)
+{
+  bool read_only = false;
+
+  auto iter = in->cbegin();
+  try {
+    uint64_t snap_id;
+    decode(snap_id, iter);
+    if (!iter.end()) {
+      decode(read_only, iter);
+    }
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+
+  CLS_LOG(20, "get_features read_only=%d", read_only);
+
+  uint64_t features;
+  int r = read_key(hctx, "features", &features);
+  if (r < 0) {
+    CLS_ERR("failed to read features off disk: %s", cpp_strerror(r).c_str());
+    return r;
+  }
+
+  uint64_t incompatible = (read_only ? features & RBD_FEATURES_INCOMPATIBLE :
+				       features & RBD_FEATURES_RW_INCOMPATIBLE);
+  encode(features, *out);
+  encode(incompatible, *out);
+  return 0;
+}
+
+/**
+ * set the image features
+ *
+ * Input:
+ * @param features image features
+ * @param mask image feature mask
+ *
+ * Output:
+ * none
+ *
+ * @returns 0 on success, negative error code upon failure
+ */
+int set_features(cls_method_context_t hctx, bufferlist *in, bufferlist *out)
+{
+  uint64_t features;
+  uint64_t mask;
+  auto iter = in->cbegin();
+  try {
+    decode(features, iter);
+    decode(mask, iter);
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+
+  // check that features exists to make sure this is a header object
+  // that was created correctly
+  uint64_t orig_features = 0;
+  int r = read_key(hctx, "features", &orig_features);
+  if (r < 0 && r != -ENOENT) {
+    CLS_ERR("Could not read image's features off disk: %s",
+            cpp_strerror(r).c_str());
+    return r;
+  }
+
+  if ((mask & RBD_FEATURES_INTERNAL) != 0ULL) {
+    CLS_ERR("Attempting to set internal feature: %" PRIu64,
+            static_cast<uint64_t>(mask & RBD_FEATURES_INTERNAL));
+    return -EINVAL;
+  }
+
+  // newer clients might attempt to mask off features we don't support
+  mask &= RBD_FEATURES_ALL;
+
+  uint64_t enabled_features = features & mask;
+  if ((enabled_features & RBD_FEATURES_MUTABLE) != enabled_features) {
+    CLS_ERR("Attempting to enable immutable feature: %" PRIu64,
+            static_cast<uint64_t>(enabled_features & ~RBD_FEATURES_MUTABLE));
+    return -EINVAL;
+  }
+
+  uint64_t disabled_features = ~features & mask;
+  uint64_t disable_mask = (RBD_FEATURES_MUTABLE | RBD_FEATURES_DISABLE_ONLY);
+  if ((disabled_features & disable_mask) != disabled_features) {
+       CLS_ERR("Attempting to disable immutable feature: %" PRIu64,
+               enabled_features & ~disable_mask);
+       return -EINVAL;
+  }
+
+  features = (orig_features & ~mask) | (features & mask);
+  CLS_LOG(10, "set_features features=%" PRIu64 " orig_features=%" PRIu64,
+          features, orig_features);
+
+  bufferlist bl;
+  encode(features, bl);
+  r = cls_cxx_map_set_val(hctx, "features", &bl);
+  if (r < 0) {
+    CLS_ERR("error updating features: %s", cpp_strerror(r).c_str());
+    return r;
+  }
+  return 0;
+}
+
+/**
+ * Input:
+ * @param snap_id which snapshot to query, or CEPH_NOSNAP (uint64_t)
+ *
+ * Output:
+ * @param order bits to shift to get the size of data objects (uint8_t)
+ * @param size size of the image in bytes for the given snapshot (uint64_t)
+ * @returns 0 on success, negative error code on failure
+ */
+int get_size(cls_method_context_t hctx, bufferlist *in, bufferlist *out)
+{
+  uint64_t snap_id, size;
+  uint8_t order;
+
+  auto iter = in->cbegin();
+  try {
+    decode(snap_id, iter);
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+
+  CLS_LOG(20, "get_size snap_id=%llu", (unsigned long long)snap_id);
+
+  int r = read_key(hctx, "order", &order);
+  if (r < 0) {
+    CLS_ERR("failed to read the order off of disk: %s", cpp_strerror(r).c_str());
+    return r;
+  }
+
+  if (snap_id == CEPH_NOSNAP) {
+    r = read_key(hctx, "size", &size);
+    if (r < 0) {
+      CLS_ERR("failed to read the image's size off of disk: %s", cpp_strerror(r).c_str());
+      return r;
+    }
+  } else {
+    cls_rbd_snap snap;
+    string snapshot_key;
+    key_from_snap_id(snap_id, &snapshot_key);
+    int r = read_key(hctx, snapshot_key, &snap);
+    if (r < 0)
+      return r;
+
+    size = snap.image_size;
+  }
+
+  encode(order, *out);
+  encode(size, *out);
+
+  return 0;
+}
+
+/**
+ * Input:
+ * @param size new capacity of the image in bytes (uint64_t)
+ *
+ * Output:
+ * @returns 0 on success, negative error code on failure
+ */
+int set_size(cls_method_context_t hctx, bufferlist *in, bufferlist *out)
+{
+  uint64_t size;
+
+  auto iter = in->cbegin();
+  try {
+    decode(size, iter);
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+
+  // check that size exists to make sure this is a header object
+  // that was created correctly
+  uint64_t orig_size;
+  int r = read_key(hctx, "size", &orig_size);
+  if (r < 0) {
+    CLS_ERR("Could not read image's size off disk: %s", cpp_strerror(r).c_str());
+    return r;
+  }
+
+  CLS_LOG(20, "set_size size=%llu orig_size=%llu", (unsigned long long)size,
+          (unsigned long long)orig_size);
+
+  bufferlist sizebl;
+  encode(size, sizebl);
+  r = cls_cxx_map_set_val(hctx, "size", &sizebl);
+  if (r < 0) {
+    CLS_ERR("error writing snapshot metadata: %s", cpp_strerror(r).c_str());
+    return r;
+  }
+
+  // if we are shrinking, and have a parent, shrink our overlap with
+  // the parent, too.
+  if (size < orig_size) {
+    cls_rbd_parent parent;
+    r = read_key(hctx, "parent", &parent);
+    if (r == -ENOENT)
+      r = 0;
+    if (r < 0)
+      return r;
+    if (parent.exists() && parent.head_overlap.value_or(0ULL) > size) {
+      parent.head_overlap = size;
+      r = write_key(hctx, "parent", parent, get_encode_features(hctx));
+      if (r < 0) {
+	return r;
+      }
+    }
+  }
+
+  return 0;
+}
+
+/**
+ * get the current protection status of the specified snapshot
+ *
+ * Input:
+ * @param snap_id (uint64_t) which snapshot to get the status of
+ *
+ * Output:
+ * @param status (uint8_t) one of:
+ * RBD_PROTECTION_STATUS_{PROTECTED, UNPROTECTED, UNPROTECTING}
+ *
+ * @returns 0 on success, negative error code on failure
+ * @returns -EINVAL if snapid is CEPH_NOSNAP
+ */
+int get_protection_status(cls_method_context_t hctx, bufferlist *in,
+			  bufferlist *out)
+{
+  snapid_t snap_id;
+
+  auto iter = in->cbegin();
+  try {
+    decode(snap_id, iter);
+  } catch (const ceph::buffer::error &err) {
+    CLS_LOG(20, "get_protection_status: invalid decode");
+    return -EINVAL;
+  }
+
+  int r = check_exists(hctx);
+  if (r < 0)
+    return r;
+
+  CLS_LOG(20, "get_protection_status snap_id=%llu",
+         (unsigned long long)snap_id.val);
+
+  if (snap_id == CEPH_NOSNAP)
+    return -EINVAL;
+
+  cls_rbd_snap snap;
+  string snapshot_key;
+  key_from_snap_id(snap_id.val, &snapshot_key);
+  r = read_key(hctx, snapshot_key, &snap);
+  if (r < 0) {
+    CLS_ERR("could not read key for snapshot id %" PRIu64, snap_id.val);
+    return r;
+  }
+
+  if (snap.protection_status >= RBD_PROTECTION_STATUS_LAST) {
+    CLS_ERR("invalid protection status for snap id %llu: %u",
+	    (unsigned long long)snap_id.val, snap.protection_status);
+    return -EIO;
+  }
+
+  encode(snap.protection_status, *out);
+  return 0;
+}
+
+/**
+ * set the proctection status of a snapshot
+ *
+ * Input:
+ * @param snapid (uint64_t) which snapshot to set the status of
+ * @param status (uint8_t) one of:
+ * RBD_PROTECTION_STATUS_{PROTECTED, UNPROTECTED, UNPROTECTING}
+ *
+ * @returns 0 on success, negative error code on failure
+ * @returns -EINVAL if snapid is CEPH_NOSNAP
+ */
+int set_protection_status(cls_method_context_t hctx, bufferlist *in,
+			  bufferlist *out)
+{
+  snapid_t snap_id;
+  uint8_t status;
+
+  auto iter = in->cbegin();
+  try {
+    decode(snap_id, iter);
+    decode(status, iter);
+  } catch (const ceph::buffer::error &err) {
+    CLS_LOG(20, "set_protection_status: invalid decode");
+    return -EINVAL;
+  }
+
+  int r = check_exists(hctx);
+  if (r < 0)
+    return r;
+
+  r = image::require_feature(hctx, RBD_FEATURE_LAYERING);
+  if (r < 0) {
+    CLS_LOG(20, "image does not support layering");
+    return r;
+  }
+
+  CLS_LOG(20, "set_protection_status snapid=%llu status=%u",
+	  (unsigned long long)snap_id.val, status);
+
+  if (snap_id == CEPH_NOSNAP)
+    return -EINVAL;
+
+  if (status >= RBD_PROTECTION_STATUS_LAST) {
+    CLS_LOG(10, "invalid protection status for snap id %llu: %u",
+	    (unsigned long long)snap_id.val, status);
+    return -EINVAL;
+  }
+
+  cls_rbd_snap snap;
+  string snapshot_key;
+  key_from_snap_id(snap_id.val, &snapshot_key);
+  r = read_key(hctx, snapshot_key, &snap);
+  if (r < 0) {
+    CLS_ERR("could not read key for snapshot id %" PRIu64, snap_id.val);
+    return r;
+  }
+
+  snap.protection_status = status;
+  r = image::snapshot::write(hctx, snapshot_key, std::move(snap));
+  if (r < 0) {
+    return r;
+  }
+
+  return 0;
+}
+
+/**
+ * get striping parameters
+ *
+ * Input:
+ * none
+ *
+ * Output:
+ * @param stripe unit (bytes)
+ * @param stripe count (num objects)
+ *
+ * @returns 0 on success
+ */
+int get_stripe_unit_count(cls_method_context_t hctx, bufferlist *in, bufferlist *out)
+{
+  int r = check_exists(hctx);
+  if (r < 0)
+    return r;
+
+  CLS_LOG(20, "get_stripe_unit_count");
+
+  r = image::require_feature(hctx, RBD_FEATURE_STRIPINGV2);
+  if (r < 0)
+    return r;
+
+  uint64_t stripe_unit = 0, stripe_count = 0;
+  r = read_key(hctx, "stripe_unit", &stripe_unit);
+  if (r == -ENOENT) {
+    // default to object size
+    uint8_t order;
+    r = read_key(hctx, "order", &order);
+    if (r < 0) {
+      CLS_ERR("failed to read the order off of disk: %s", cpp_strerror(r).c_str());
+      return -EIO;
+    }
+    stripe_unit = 1ull << order;
+  }
+  if (r < 0)
+    return r;
+  r = read_key(hctx, "stripe_count", &stripe_count);
+  if (r == -ENOENT) {
+    // default to 1
+    stripe_count = 1;
+    r = 0;
+  }
+  if (r < 0)
+    return r;
+
+  encode(stripe_unit, *out);
+  encode(stripe_count, *out);
+  return 0;
+}
+
+/**
+ * set striping parameters
+ *
+ * Input:
+ * @param stripe unit (bytes)
+ * @param stripe count (num objects)
+ *
+ * @returns 0 on success
+ */
+int set_stripe_unit_count(cls_method_context_t hctx, bufferlist *in, bufferlist *out)
+{
+  uint64_t stripe_unit, stripe_count;
+
+  auto iter = in->cbegin();
+  try {
+    decode(stripe_unit, iter);
+    decode(stripe_count, iter);
+  } catch (const ceph::buffer::error &err) {
+    CLS_LOG(20, "set_stripe_unit_count: invalid decode");
+    return -EINVAL;
+  }
+
+  if (!stripe_count || !stripe_unit)
+    return -EINVAL;
+
+  int r = check_exists(hctx);
+  if (r < 0)
+    return r;
+
+  CLS_LOG(20, "set_stripe_unit_count");
+
+  r = image::require_feature(hctx, RBD_FEATURE_STRIPINGV2);
+  if (r < 0)
+    return r;
+
+  uint8_t order;
+  r = read_key(hctx, "order", &order);
+  if (r < 0) {
+    CLS_ERR("failed to read the order off of disk: %s", cpp_strerror(r).c_str());
+    return r;
+  }
+  if ((1ull << order) % stripe_unit || stripe_unit > (1ull << order)) {
+    CLS_ERR("stripe unit %llu is not a factor of the object size %llu",
+            (unsigned long long)stripe_unit, 1ull << order);
+    return -EINVAL;
+  }
+
+  bufferlist bl, bl2;
+  encode(stripe_unit, bl);
+  r = cls_cxx_map_set_val(hctx, "stripe_unit", &bl);
+  if (r < 0) {
+    CLS_ERR("error writing stripe_unit metadata: %s", cpp_strerror(r).c_str());
+    return r;
+  }
+
+  encode(stripe_count, bl2);
+  r = cls_cxx_map_set_val(hctx, "stripe_count", &bl2);
+  if (r < 0) {
+    CLS_ERR("error writing stripe_count metadata: %s", cpp_strerror(r).c_str());
+    return r;
+  }
+
+  return 0;
+}
+
+int get_create_timestamp(cls_method_context_t hctx, bufferlist *in, bufferlist *out)
+{
+  CLS_LOG(20, "get_create_timestamp");
+
+  utime_t timestamp;
+  bufferlist bl;
+  int r = cls_cxx_map_get_val(hctx, "create_timestamp", &bl);
+  if (r < 0) {
+    if (r != -ENOENT) {
+      CLS_ERR("error reading create_timestamp: %s", cpp_strerror(r).c_str());
+      return r;
+    }
+  } else {
+    try {
+      auto it = bl.cbegin();
+      decode(timestamp, it);
+    } catch (const ceph::buffer::error &err) {
+      CLS_ERR("could not decode create_timestamp");
+      return -EIO;
+    }
+  }
+
+  encode(timestamp, *out);
+  return 0;
+}
+
+/**
+ * get the image access timestamp
+ *
+ * Input:
+ * @param none
+ *
+ * Output:
+ * @param timestamp the image access timestamp
+ *
+ * @returns 0 on success, negative error code upon failure
+ */
+int get_access_timestamp(cls_method_context_t hctx, bufferlist *in, bufferlist *out)
+{
+  CLS_LOG(20, "get_access_timestamp");
+
+  utime_t timestamp;
+  bufferlist bl;
+  int r = cls_cxx_map_get_val(hctx, "access_timestamp", &bl);
+  if (r < 0) {
+    if (r != -ENOENT) {
+      CLS_ERR("error reading access_timestamp: %s", cpp_strerror(r).c_str());
+      return r;
+    }
+  } else {
+    try {
+      auto it = bl.cbegin();
+      decode(timestamp, it);
+    } catch (const ceph::buffer::error &err) {
+      CLS_ERR("could not decode access_timestamp");
+      return -EIO;
+    }
+  }
+
+  encode(timestamp, *out);
+  return 0;
+}
+
+/**
+ * get the image modify timestamp
+ *
+ * Input:
+ * @param none
+ *
+ * Output:
+ * @param timestamp the image modify timestamp
+ *
+ * @returns 0 on success, negative error code upon failure
+ */
+int get_modify_timestamp(cls_method_context_t hctx, bufferlist *in, bufferlist *out)
+{
+  CLS_LOG(20, "get_modify_timestamp");
+
+  utime_t timestamp;
+  bufferlist bl;
+  int r = cls_cxx_map_get_val(hctx, "modify_timestamp", &bl);
+  if (r < 0) {
+    if (r != -ENOENT) {
+      CLS_ERR("error reading modify_timestamp: %s", cpp_strerror(r).c_str());
+      return r;
+    }
+  } else {
+    try {
+      auto it = bl.cbegin();
+      decode(timestamp, it);
+    } catch (const ceph::buffer::error &err) {
+      CLS_ERR("could not decode modify_timestamp");
+      return -EIO;
+    }
+  }
+
+  encode(timestamp, *out);
+  return 0;
+}
+
+
+/**
+ * get the image flags
+ *
+ * Input:
+ * @param snap_id which snapshot to query, to CEPH_NOSNAP (uint64_t)
+ *
+ * Output:
+ * @param flags image flags
+ *
+ * @returns 0 on success, negative error code upon failure
+ */
+int get_flags(cls_method_context_t hctx, bufferlist *in, bufferlist *out)
+{
+  uint64_t snap_id;
+  auto iter = in->cbegin();
+  try {
+    decode(snap_id, iter);
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+
+  CLS_LOG(20, "get_flags snap_id=%llu", (unsigned long long)snap_id);
+
+  uint64_t flags = 0;
+  if (snap_id == CEPH_NOSNAP) {
+    int r = read_key(hctx, "flags", &flags);
+    if (r < 0 && r != -ENOENT) {
+      CLS_ERR("failed to read flags off disk: %s", cpp_strerror(r).c_str());
+      return r;
+    }
+  } else {
+    cls_rbd_snap snap;
+    string snapshot_key;
+    key_from_snap_id(snap_id, &snapshot_key);
+    int r = read_key(hctx, snapshot_key, &snap);
+    if (r < 0) {
+      return r;
+    }
+    flags = snap.flags;
+  }
+
+  encode(flags, *out);
+  return 0;
+}
+
+/**
+ * set the image flags
+ *
+ * Input:
+ * @param flags image flags
+ * @param mask image flag mask
+ * @param snap_id which snapshot to update, or CEPH_NOSNAP (uint64_t)
+ *
+ * Output:
+ * none
+ *
+ * @returns 0 on success, negative error code upon failure
+ */
+int set_flags(cls_method_context_t hctx, bufferlist *in, bufferlist *out)
+{
+  uint64_t flags;
+  uint64_t mask;
+  uint64_t snap_id = CEPH_NOSNAP;
+  auto iter = in->cbegin();
+  try {
+    decode(flags, iter);
+    decode(mask, iter);
+    if (!iter.end()) {
+      decode(snap_id, iter);
+    }
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+
+  // check that size exists to make sure this is a header object
+  // that was created correctly
+  int r;
+  uint64_t orig_flags = 0;
+  cls_rbd_snap snap_meta;
+  string snap_meta_key;
+  if (snap_id == CEPH_NOSNAP) {
+    r = read_key(hctx, "flags", &orig_flags);
+    if (r < 0 && r != -ENOENT) {
+      CLS_ERR("Could not read image's flags off disk: %s",
+              cpp_strerror(r).c_str());
+      return r;
+    }
+  } else {
+    key_from_snap_id(snap_id, &snap_meta_key);
+    r = read_key(hctx, snap_meta_key, &snap_meta);
+    if (r < 0) {
+      CLS_ERR("Could not read snapshot: snap_id=%" PRIu64 ": %s",
+              snap_id, cpp_strerror(r).c_str());
+      return r;
+    }
+    orig_flags = snap_meta.flags;
+  }
+
+  flags = (orig_flags & ~mask) | (flags & mask);
+  CLS_LOG(20, "set_flags snap_id=%" PRIu64 ", orig_flags=%" PRIu64 ", "
+              "new_flags=%" PRIu64 ", mask=%" PRIu64, snap_id, orig_flags,
+              flags, mask);
+
+  if (snap_id == CEPH_NOSNAP) {
+    r = write_key(hctx, "flags", flags);
+  } else {
+    snap_meta.flags = flags;
+    r = image::snapshot::write(hctx, snap_meta_key, std::move(snap_meta));
+  }
+
+  if (r < 0) {
+    return r;
+  }
+  return 0;
+}
+
+/**
+ * Get the operation-based image features
+ *
+ * Input:
+ *
+ * Output:
+ * @param bitmask of enabled op features (uint64_t)
+ * @returns 0 on success, negative error code on failure
+ */
+int op_features_get(cls_method_context_t hctx, bufferlist *in, bufferlist *out)
+{
+  CLS_LOG(20, "op_features_get");
+
+  uint64_t op_features = 0;
+  int r = read_key(hctx, "op_features", &op_features);
+  if (r < 0 && r != -ENOENT) {
+    CLS_ERR("failed to read op features off disk: %s", cpp_strerror(r).c_str());
+    return r;
+  }
+
+  encode(op_features, *out);
+  return 0;
+}
+
+/**
+ * Set the operation-based image features
+ *
+ * Input:
+ * @param op_features image op features
+ * @param mask image op feature mask
+ *
+ * Output:
+ * none
+ *
+ * @returns 0 on success, negative error code upon failure
+ */
+int op_features_set(cls_method_context_t hctx, bufferlist *in, bufferlist *out)
+{
+  uint64_t op_features;
+  uint64_t mask;
+  auto iter = in->cbegin();
+  try {
+    decode(op_features, iter);
+    decode(mask, iter);
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+
+  uint64_t unsupported_op_features = (mask & ~RBD_OPERATION_FEATURES_ALL);
+  if (unsupported_op_features != 0ULL) {
+    CLS_ERR("unsupported op features: %" PRIu64, unsupported_op_features);
+    return -EINVAL;
+  }
+
+  return image::set_op_features(hctx, op_features, mask);
+}
+
+/**
+ * get the current parent, if any
+ *
+ * Input:
+ * @param snap_id which snapshot to query, or CEPH_NOSNAP (uint64_t)
+ *
+ * Output:
+ * @param pool parent pool id (-1 if parent does not exist)
+ * @param image parent image id
+ * @param snapid parent snapid
+ * @param size portion of parent mapped under the child
+ *
+ * @returns 0 on success or parent does not exist, negative error code on failure
+ */
+int get_parent(cls_method_context_t hctx, bufferlist *in, bufferlist *out)
+{
+  uint64_t snap_id;
+
+  auto iter = in->cbegin();
+  try {
+    decode(snap_id, iter);
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+
+  int r = check_exists(hctx);
+  if (r < 0) {
+    return r;
+  }
+
+  CLS_LOG(20, "get_parent snap_id=%" PRIu64, snap_id);
+
+  cls_rbd_parent parent;
+  r = image::require_feature(hctx, RBD_FEATURE_LAYERING);
+  if (r == 0) {
+    r = read_key(hctx, "parent", &parent);
+    if (r < 0 && r != -ENOENT) {
+      return r;
+    } else if (!parent.pool_namespace.empty()) {
+      return -EXDEV;
+    }
+
+    if (snap_id != CEPH_NOSNAP) {
+      cls_rbd_snap snap;
+      std::string snapshot_key;
+      key_from_snap_id(snap_id, &snapshot_key);
+      r = read_key(hctx, snapshot_key, &snap);
+      if (r < 0 && r != -ENOENT) {
+	return r;
+      }
+
+      if (snap.parent.exists()) {
+        // legacy format where full parent spec is written within
+        // each snapshot record
+        parent = snap.parent;
+      } else if (snap.parent_overlap) {
+        // normalized parent reference
+        if (!parent.exists()) {
+          CLS_ERR("get_parent: snap_id=%" PRIu64 ": invalid parent spec",
+                  snap_id);
+          return -EINVAL;
+        }
+        parent.head_overlap = *snap.parent_overlap;
+      } else {
+        // snapshot doesn't have associated parent
+        parent = {};
+      }
+    }
+  }
+
+  encode(parent.pool_id, *out);
+  encode(parent.image_id, *out);
+  encode(parent.snap_id, *out);
+  encode(parent.head_overlap.value_or(0ULL), *out);
+  return 0;
+}
+
+/**
+ * set the image parent
+ *
+ * Input:
+ * @param pool parent pool
+ * @param id parent image id
+ * @param snapid parent snapid
+ * @param size parent size
+ *
+ * @returns 0 on success, or negative error code
+ */
+int set_parent(cls_method_context_t hctx, bufferlist *in, bufferlist *out)
+{
+  cls_rbd_parent parent;
+  auto iter = in->cbegin();
+  try {
+    decode(parent.pool_id, iter);
+    decode(parent.image_id, iter);
+    decode(parent.snap_id, iter);
+
+    uint64_t overlap;
+    decode(overlap, iter);
+    parent.head_overlap = overlap;
+  } catch (const ceph::buffer::error &err) {
+    CLS_LOG(20, "cls_rbd::set_parent: invalid decode");
+    return -EINVAL;
+  }
+
+  int r = image::parent::attach(hctx, parent, false);
+  if (r < 0) {
+    return r;
+  }
+
+  return 0;
+}
+
+
+/**
+ * remove the parent pointer
+ *
+ * This can only happen on the head, not on a snapshot.  No arguments.
+ *
+ * @returns 0 on success, negative error code on failure.
+ */
+int remove_parent(cls_method_context_t hctx, bufferlist *in, bufferlist *out)
+{
+  int r = image::parent::detach(hctx, true);
+  if (r < 0) {
+    return r;
+  }
+
+  return 0;
+}
+
+/**
+ * Input:
+ * none
+ *
+ * Output:
+ * @param parent spec (cls::rbd::ParentImageSpec)
+ * @returns 0 on success, negative error code on failure
+ */
+int parent_get(cls_method_context_t hctx, bufferlist *in, bufferlist *out) {
+  int r = check_exists(hctx);
+  if (r < 0) {
+    return r;
+  }
+
+  CLS_LOG(20, "parent_get");
+
+  cls_rbd_parent parent;
+  r = image::require_feature(hctx, RBD_FEATURE_LAYERING);
+  if (r == 0) {
+    r = read_key(hctx, "parent", &parent);
+    if (r < 0 && r != -ENOENT) {
+      return r;
+    } else if (r == -ENOENT) {
+      // examine oldest snapshot to see if it has a denormalized parent
+      auto parent_lambda = [&parent](const cls_rbd_snap& snap_meta) {
+        if (snap_meta.parent.exists()) {
+          parent = snap_meta.parent;
+        }
+        return 0;
+      };
+
+      r = image::snapshot::iterate(hctx, parent_lambda);
+      if (r < 0) {
+        return r;
+      }
+    }
+  }
+
+  cls::rbd::ParentImageSpec parent_image_spec{
+    parent.pool_id, parent.pool_namespace, parent.image_id,
+    parent.snap_id};
+  encode(parent_image_spec, *out);
+  return 0;
+}
+
+/**
+ * Input:
+ * @param snap id (uint64_t) parent snapshot id
+ *
+ * Output:
+ * @param byte overlap of parent image (std::optional<uint64_t>)
+ * @returns 0 on success, negative error code on failure
+ */
+int parent_overlap_get(cls_method_context_t hctx, bufferlist *in,
+                       bufferlist *out) {
+  uint64_t snap_id;
+  auto iter = in->cbegin();
+  try {
+    decode(snap_id, iter);
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+
+  int r = check_exists(hctx);
+  CLS_LOG(20, "parent_overlap_get");
+
+  std::optional<uint64_t> parent_overlap = std::nullopt;
+  r = image::require_feature(hctx, RBD_FEATURE_LAYERING);
+  if (r == 0) {
+    if (snap_id == CEPH_NOSNAP) {
+      cls_rbd_parent parent;
+      r = read_key(hctx, "parent", &parent);
+      if (r < 0 && r != -ENOENT) {
+        return r;
+      } else if (r == 0) {
+        parent_overlap = parent.head_overlap;
+      }
+    } else {
+      cls_rbd_snap snap;
+      std::string snapshot_key;
+      key_from_snap_id(snap_id, &snapshot_key);
+      r = read_key(hctx, snapshot_key, &snap);
+      if (r < 0) {
+        return r;
+      }
+
+      if (snap.parent_overlap) {
+        parent_overlap = snap.parent_overlap;
+      } else if (snap.parent.exists()) {
+        // legacy format where full parent spec is written within
+        // each snapshot record
+        parent_overlap = snap.parent.head_overlap;
+      }
+    }
+  };
+
+  encode(parent_overlap, *out);
+  return 0;
+}
+
+/**
+ * Input:
+ * @param parent spec (cls::rbd::ParentImageSpec)
+ * @param size parent size (uint64_t)
+ *
+ * Output:
+ * @returns 0 on success, negative error code on failure
+ */
+int parent_attach(cls_method_context_t hctx, bufferlist *in, bufferlist *out) {
+  cls::rbd::ParentImageSpec parent_image_spec;
+  uint64_t parent_overlap;
+  bool reattach = false;
+
+  auto iter = in->cbegin();
+  try {
+    decode(parent_image_spec, iter);
+    decode(parent_overlap, iter);
+    if (!iter.end()) {
+      decode(reattach, iter);
+    }
+  } catch (const ceph::buffer::error &err) {
+    CLS_LOG(20, "cls_rbd::parent_attach: invalid decode");
+    return -EINVAL;
+  }
+
+  int r = image::parent::attach(hctx, {parent_image_spec, parent_overlap},
+                                reattach);
+  if (r < 0) {
+    return r;
+  }
+
+  return 0;
+}
+
+/**
+ * Input:
+ * none
+ *
+ * Output:
+ * @returns 0 on success, negative error code on failure
+ */
+int parent_detach(cls_method_context_t hctx, bufferlist *in, bufferlist *out) {
+  int r = image::parent::detach(hctx, false);
+  if (r < 0) {
+    return r;
+  }
+
+  return 0;
+}
+
+
+/**
+ * methods for dealing with rbd_children object
+ */
+
+static int decode_parent_common(bufferlist::const_iterator& it, uint64_t *pool_id,
+				string *image_id, snapid_t *snap_id)
+{
+  try {
+    decode(*pool_id, it);
+    decode(*image_id, it);
+    decode(*snap_id, it);
+  } catch (const ceph::buffer::error &err) {
+    CLS_ERR("error decoding parent spec");
+    return -EINVAL;
+  }
+  return 0;
+}
+
+static int decode_parent(bufferlist *in, uint64_t *pool_id,
+			 string *image_id, snapid_t *snap_id)
+{
+  auto it = in->cbegin();
+  return decode_parent_common(it, pool_id, image_id, snap_id);
+}
+
+static int decode_parent_and_child(bufferlist *in, uint64_t *pool_id,
+			           string *image_id, snapid_t *snap_id,
+				   string *c_image_id)
+{
+  auto it = in->cbegin();
+  int r = decode_parent_common(it, pool_id, image_id, snap_id);
+  if (r < 0)
+    return r;
+  try {
+    decode(*c_image_id, it);
+  } catch (const ceph::buffer::error &err) {
+    CLS_ERR("error decoding child image id");
+    return -EINVAL;
+  }
+  return 0;
+}
+
+static string parent_key(uint64_t pool_id, string image_id, snapid_t snap_id)
+{
+  bufferlist key_bl;
+  encode(pool_id, key_bl);
+  encode(image_id, key_bl);
+  encode(snap_id, key_bl);
+  return string(key_bl.c_str(), key_bl.length());
+}
+
+/**
+ * add child to rbd_children directory object
+ *
+ * rbd_children is a map of (p_pool_id, p_image_id, p_snap_id) to
+ * [c_image_id, [c_image_id ... ]]
+ *
+ * Input:
+ * @param p_pool_id parent pool id
+ * @param p_image_id parent image oid
+ * @param p_snap_id parent snapshot id
+ * @param c_image_id new child image oid to add
+ *
+ * @returns 0 on success, negative error on failure
+ */
+
+int add_child(cls_method_context_t hctx, bufferlist *in, bufferlist *out)
+{
+  int r;
+
+  uint64_t p_pool_id;
+  snapid_t p_snap_id;
+  string p_image_id, c_image_id;
+  // Use set for ease of erase() for remove_child()
+  std::set<string> children;
+
+  r = decode_parent_and_child(in, &p_pool_id, &p_image_id, &p_snap_id,
+			      &c_image_id);
+  if (r < 0)
+    return r;
+
+  CLS_LOG(20, "add_child %s to (%" PRIu64 ", %s, %" PRIu64 ")", c_image_id.c_str(),
+	  p_pool_id, p_image_id.c_str(), p_snap_id.val);
+
+  string key = parent_key(p_pool_id, p_image_id, p_snap_id);
+
+  // get current child list for parent, if any
+  r = read_key(hctx, key, &children);
+  if ((r < 0) && (r != -ENOENT)) {
+    CLS_LOG(20, "add_child: omap read failed: %s", cpp_strerror(r).c_str());
+    return r;
+  }
+
+  if (children.find(c_image_id) != children.end()) {
+    CLS_LOG(20, "add_child: child already exists: %s", c_image_id.c_str());
+    return -EEXIST;
+  }
+  // add new child
+  children.insert(c_image_id);
+
+  // write back
+  bufferlist childbl;
+  encode(children, childbl);
+  r = cls_cxx_map_set_val(hctx, key, &childbl);
+  if (r < 0)
+    CLS_LOG(20, "add_child: omap write failed: %s", cpp_strerror(r).c_str());
+  return r;
+}
+
+/**
+ * remove child from rbd_children directory object
+ *
+ * Input:
+ * @param p_pool_id parent pool id
+ * @param p_image_id parent image oid
+ * @param p_snap_id parent snapshot id
+ * @param c_image_id new child image oid to add
+ *
+ * @returns 0 on success, negative error on failure
+ */
+
+int remove_child(cls_method_context_t hctx, bufferlist *in, bufferlist *out)
+{
+  int r;
+
+  uint64_t p_pool_id;
+  snapid_t p_snap_id;
+  string p_image_id, c_image_id;
+  std::set<string> children;
+
+  r = decode_parent_and_child(in, &p_pool_id, &p_image_id, &p_snap_id,
+			      &c_image_id);
+  if (r < 0)
+    return r;
+
+  CLS_LOG(20, "remove_child %s from (%" PRIu64 ", %s, %" PRIu64 ")",
+	       c_image_id.c_str(), p_pool_id, p_image_id.c_str(),
+	       p_snap_id.val);
+
+  string key = parent_key(p_pool_id, p_image_id, p_snap_id);
+
+  // get current child list for parent.  Unlike add_child(), an empty list
+  // is an error (how can we remove something that doesn't exist?)
+  r = read_key(hctx, key, &children);
+  if (r < 0) {
+    CLS_LOG(20, "remove_child: read omap failed: %s", cpp_strerror(r).c_str());
+    return r;
+  }
+
+  if (children.find(c_image_id) == children.end()) {
+    CLS_LOG(20, "remove_child: child not found: %s", c_image_id.c_str());
+    return -ENOENT;
+  }
+  // find and remove child
+  children.erase(c_image_id);
+
+  // now empty?  remove key altogether
+  if (children.empty()) {
+    r = cls_cxx_map_remove_key(hctx, key);
+    if (r < 0)
+      CLS_LOG(20, "remove_child: remove key failed: %s", cpp_strerror(r).c_str());
+  } else {
+    // write back shortened children list
+    bufferlist childbl;
+    encode(children, childbl);
+    r = cls_cxx_map_set_val(hctx, key, &childbl);
+    if (r < 0)
+      CLS_LOG(20, "remove_child: write omap failed: %s", cpp_strerror(r).c_str());
+  }
+  return r;
+}
+
+/**
+ * Input:
+ * @param p_pool_id parent pool id
+ * @param p_image_id parent image oid
+ * @param p_snap_id parent snapshot id
+ * @param c_image_id new child image oid to add
+ *
+ * Output:
+ * @param children set<string> of children
+ *
+ * @returns 0 on success, negative error on failure
+ */
+int get_children(cls_method_context_t hctx, bufferlist *in, bufferlist *out)
+{
+  int r;
+  uint64_t p_pool_id;
+  snapid_t p_snap_id;
+  string p_image_id;
+  std::set<string> children;
+
+  r = decode_parent(in, &p_pool_id, &p_image_id, &p_snap_id);
+  if (r < 0)
+    return r;
+
+  CLS_LOG(20, "get_children of (%" PRIu64 ", %s, %" PRIu64 ")",
+	  p_pool_id, p_image_id.c_str(), p_snap_id.val);
+
+  string key = parent_key(p_pool_id, p_image_id, p_snap_id);
+
+  r = read_key(hctx, key, &children);
+  if (r < 0) {
+    if (r != -ENOENT)
+      CLS_LOG(20, "get_children: read omap failed: %s", cpp_strerror(r).c_str());
+    return r;
+  }
+  encode(children, *out);
+  return 0;
+}
+
+
+/**
+ * Get the information needed to create a rados snap context for doing
+ * I/O to the data objects. This must include all snapshots.
+ *
+ * Output:
+ * @param snap_seq the highest snapshot id ever associated with the image (uint64_t)
+ * @param snap_ids existing snapshot ids in descending order (vector<uint64_t>)
+ * @returns 0 on success, negative error code on failure
+ */
+int get_snapcontext(cls_method_context_t hctx, bufferlist *in, bufferlist *out)
+{
+  CLS_LOG(20, "get_snapcontext");
+
+  int r;
+  int max_read = RBD_MAX_KEYS_READ;
+  vector<snapid_t> snap_ids;
+  string last_read = RBD_SNAP_KEY_PREFIX;
+  bool more;
+
+  do {
+    set<string> keys;
+    r = cls_cxx_map_get_keys(hctx, last_read, max_read, &keys, &more);
+    if (r < 0)
+      return r;
+
+    for (auto it = keys.begin(); it != keys.end(); ++it) {
+      if ((*it).find(RBD_SNAP_KEY_PREFIX) != 0)
+	break;
+      snapid_t snap_id = snap_id_from_key(*it);
+      snap_ids.push_back(snap_id);
+    }
+    if (!keys.empty())
+      last_read = *(keys.rbegin());
+  } while (more);
+
+  uint64_t snap_seq;
+  r = read_key(hctx, "snap_seq", &snap_seq);
+  if (r < 0) {
+    CLS_ERR("could not read the image's snap_seq off disk: %s", cpp_strerror(r).c_str());
+    return r;
+  }
+
+  // snap_ids must be descending in a snap context
+  std::reverse(snap_ids.begin(), snap_ids.end());
+
+  encode(snap_seq, *out);
+  encode(snap_ids, *out);
+
+  return 0;
+}
+
+/**
+ * Output:
+ * @param object_prefix prefix for data object names (string)
+ * @returns 0 on success, negative error code on failure
+ */
+int get_object_prefix(cls_method_context_t hctx, bufferlist *in, bufferlist *out)
+{
+  CLS_LOG(20, "get_object_prefix");
+
+  string object_prefix;
+  int r = read_key(hctx, "object_prefix", &object_prefix);
+  if (r < 0) {
+    CLS_ERR("failed to read the image's object prefix off of disk: %s",
+            cpp_strerror(r).c_str());
+    return r;
+  }
+
+  encode(object_prefix, *out);
+
+  return 0;
+}
+
+/**
+ * Input:
+ * none
+ *
+ * Output:
+ * @param pool_id (int64_t) of data pool or -1 if none
+ * @returns 0 on success, negative error code on failure
+ */
+int get_data_pool(cls_method_context_t hctx, bufferlist *in, bufferlist *out)
+{
+  CLS_LOG(20, "get_data_pool");
+
+  int64_t data_pool_id = -1;
+  int r = read_key(hctx, "data_pool_id", &data_pool_id);
+  if (r == -ENOENT) {
+    data_pool_id = -1;
+  } else if (r < 0) {
+    CLS_ERR("error reading image data pool id: %s", cpp_strerror(r).c_str());
+    return r;
+  }
+
+  encode(data_pool_id, *out);
+  return 0;
+}
+
+/**
+ * Input:
+ * @param snap_id which snapshot to query
+ *
+ * Output:
+ * @param name (string) of the snapshot
+ * @returns 0 on success, negative error code on failure
+ */
+int get_snapshot_name(cls_method_context_t hctx, bufferlist *in, bufferlist *out)
+{
+  uint64_t snap_id;
+
+  auto iter = in->cbegin();
+  try {
+    decode(snap_id, iter);
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+
+  CLS_LOG(20, "get_snapshot_name snap_id=%llu", (unsigned long long)snap_id);
+
+  if (snap_id == CEPH_NOSNAP)
+    return -EINVAL;
+
+  cls_rbd_snap snap;
+  string snapshot_key;
+  key_from_snap_id(snap_id, &snapshot_key);
+  int r = read_key(hctx, snapshot_key, &snap);
+  if (r < 0)
+    return r;
+
+  encode(snap.name, *out);
+
+  return 0;
+}
+
+/**
+ * Input:
+ * @param snap_id which snapshot to query
+ *
+ * Output:
+ * @param timestamp (utime_t) of the snapshot
+ * @returns 0 on success, negative error code on failure
+ *
+ * NOTE: deprecated - remove this method after Luminous is unsupported
+ */
+int get_snapshot_timestamp(cls_method_context_t hctx, bufferlist *in, bufferlist *out)
+{
+  uint64_t snap_id;
+
+  auto iter = in->cbegin();
+  try {
+    decode(snap_id, iter);
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+
+  CLS_LOG(20, "get_snapshot_timestamp snap_id=%llu", (unsigned long long)snap_id);
+
+  if (snap_id == CEPH_NOSNAP) {
+    return -EINVAL;
+  }
+
+  cls_rbd_snap snap;
+  string snapshot_key;
+  key_from_snap_id(snap_id, &snapshot_key);
+  int r = read_key(hctx, snapshot_key, &snap);
+  if (r < 0) {
+    return r;
+  }
+
+  encode(snap.timestamp, *out);
+  return 0;
+}
+
+/**
+ * Input:
+ * @param snap_id which snapshot to query
+ *
+ * Output:
+ * @param snapshot (cls::rbd::SnapshotInfo)
+ * @returns 0 on success, negative error code on failure
+ */
+int snapshot_get(cls_method_context_t hctx, bufferlist *in, bufferlist *out)
+{
+  uint64_t snap_id;
+
+  auto iter = in->cbegin();
+  try {
+    decode(snap_id, iter);
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+
+  CLS_LOG(20, "snapshot_get snap_id=%llu", (unsigned long long)snap_id);
+  if (snap_id == CEPH_NOSNAP) {
+    return -EINVAL;
+  }
+
+  cls_rbd_snap snap;
+  string snapshot_key;
+  key_from_snap_id(snap_id, &snapshot_key);
+  int r = read_key(hctx, snapshot_key, &snap);
+  if (r < 0) {
+    return r;
+  }
+
+  cls::rbd::SnapshotInfo snapshot_info{snap.id, snap.snapshot_namespace,
+                                       snap.name, snap.image_size,
+                                       snap.timestamp, snap.child_count};
+  encode(snapshot_info, *out);
+  return 0;
+}
+
+/**
+ * Adds a snapshot to an rbd header. Ensures the id and name are unique.
+ *
+ * Input:
+ * @param snap_name name of the snapshot (string)
+ * @param snap_id id of the snapshot (uint64_t)
+ * @param snap_namespace namespace of the snapshot (cls::rbd::SnapshotNamespace)
+ *
+ * Output:
+ * @returns 0 on success, negative error code on failure.
+ * @returns -ESTALE if the input snap_id is less than the image's snap_seq
+ * @returns -EEXIST if the id or name are already used by another snapshot
+ */
+int snapshot_add(cls_method_context_t hctx, bufferlist *in, bufferlist *out)
+{
+  bufferlist snap_namebl, snap_idbl;
+  cls_rbd_snap snap_meta;
+  uint64_t snap_limit;
+
+  try {
+    auto iter = in->cbegin();
+    decode(snap_meta.name, iter);
+    decode(snap_meta.id, iter);
+    if (!iter.end()) {
+      decode(snap_meta.snapshot_namespace, iter);
+    }
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+
+  if (boost::get<cls::rbd::UnknownSnapshotNamespace>(
+        &snap_meta.snapshot_namespace) != nullptr) {
+    CLS_ERR("Unknown snapshot namespace provided");
+    return -EINVAL;
+  }
+
+  CLS_LOG(20, "snapshot_add name=%s id=%llu", snap_meta.name.c_str(),
+	 (unsigned long long)snap_meta.id.val);
+
+  if (snap_meta.id > CEPH_MAXSNAP)
+    return -EINVAL;
+
+  uint64_t cur_snap_seq;
+  int r = read_key(hctx, "snap_seq", &cur_snap_seq);
+  if (r < 0) {
+    CLS_ERR("Could not read image's snap_seq off disk: %s", cpp_strerror(r).c_str());
+    return r;
+  }
+
+  // client lost a race with another snapshot creation.
+  // snap_seq must be monotonically increasing.
+  if (snap_meta.id < cur_snap_seq)
+    return -ESTALE;
+
+  r = read_key(hctx, "size", &snap_meta.image_size);
+  if (r < 0) {
+    CLS_ERR("Could not read image's size off disk: %s", cpp_strerror(r).c_str());
+    return r;
+  }
+  r = read_key(hctx, "flags", &snap_meta.flags);
+  if (r < 0 && r != -ENOENT) {
+    CLS_ERR("Could not read image's flags off disk: %s", cpp_strerror(r).c_str());
+    return r;
+  }
+
+  r = read_key(hctx, "snap_limit", &snap_limit);
+  if (r == -ENOENT) {
+    snap_limit = UINT64_MAX;
+  } else if (r < 0) {
+    CLS_ERR("Could not read snapshot limit off disk: %s", cpp_strerror(r).c_str());
+    return r;
+  }
+
+  snap_meta.timestamp = ceph_clock_now();
+
+  uint64_t total_read = 0;
+  auto pre_check_lambda =
+    [&snap_meta, &total_read, snap_limit](const cls_rbd_snap& old_meta) {
+      ++total_read;
+      if (total_read >= snap_limit) {
+        CLS_ERR("Attempt to create snapshot over limit of %" PRIu64,
+                snap_limit);
+        return -EDQUOT;
+      }
+
+      if ((snap_meta.name == old_meta.name &&
+	    snap_meta.snapshot_namespace == old_meta.snapshot_namespace) ||
+	  snap_meta.id == old_meta.id) {
+	CLS_LOG(20, "snap_name %s or snap_id %" PRIu64 " matches existing snap "
+                "%s %" PRIu64, snap_meta.name.c_str(), snap_meta.id.val,
+		old_meta.name.c_str(), old_meta.id.val);
+	return -EEXIST;
+      }
+      return 0;
+    };
+
+  r = image::snapshot::iterate(hctx, pre_check_lambda);
+  if (r < 0) {
+    return r;
+  }
+
+  // snapshot inherits parent, if any
+  cls_rbd_parent parent;
+  r = read_key(hctx, "parent", &parent);
+  if (r < 0 && r != -ENOENT) {
+    return r;
+  }
+  if (r == 0) {
+    // write helper method will convert to normalized format if required
+    snap_meta.parent = parent;
+  }
+
+  if (cls::rbd::get_snap_namespace_type(snap_meta.snapshot_namespace) ==
+        cls::rbd::SNAPSHOT_NAMESPACE_TYPE_TRASH) {
+    // add snap_trash feature bit if not already enabled
+    r = image::set_op_features(hctx, RBD_OPERATION_FEATURE_SNAP_TRASH,
+                               RBD_OPERATION_FEATURE_SNAP_TRASH);
+    if (r < 0) {
+      return r;
+    }
+  }
+
+  r = write_key(hctx, "snap_seq", snap_meta.id);
+  if (r < 0) {
+    return r;
+  }
+
+  std::string snapshot_key;
+  key_from_snap_id(snap_meta.id, &snapshot_key);
+  r = image::snapshot::write(hctx, snapshot_key, std::move(snap_meta));
+  if (r < 0) {
+    return r;
+  }
+
+  return 0;
+}
+
+/**
+ * rename snapshot .
+ *
+ * Input:
+ * @param src_snap_id old snap id of the snapshot (snapid_t)
+ * @param dst_snap_name new name of the snapshot (string)
+ *
+ * Output:
+ * @returns 0 on success, negative error code on failure.
+ */
+int snapshot_rename(cls_method_context_t hctx, bufferlist *in, bufferlist *out)
+{
+  bufferlist snap_namebl, snap_idbl;
+  snapid_t src_snap_id;
+  string dst_snap_name;
+  cls_rbd_snap snap_meta;
+  int r;
+
+  try {
+    auto iter = in->cbegin();
+    decode(src_snap_id, iter);
+    decode(dst_snap_name, iter);
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+
+  CLS_LOG(20, "snapshot_rename id=%" PRIu64 ", dst_name=%s",
+          src_snap_id.val, dst_snap_name.c_str());
+
+  auto duplicate_name_lambda = [&dst_snap_name](const cls_rbd_snap& snap_meta) {
+    if (cls::rbd::get_snap_namespace_type(snap_meta.snapshot_namespace) ==
+          cls::rbd::SNAPSHOT_NAMESPACE_TYPE_USER &&
+        snap_meta.name == dst_snap_name) {
+      CLS_LOG(20, "snap_name %s matches existing snap with snap id %" PRIu64,
+              dst_snap_name.c_str(), snap_meta.id.val);
+      return -EEXIST;
+    }
+    return 0;
+  };
+  r = image::snapshot::iterate(hctx, duplicate_name_lambda);
+  if (r < 0) {
+    return r;
+  }
+
+  std::string src_snap_key;
+  key_from_snap_id(src_snap_id, &src_snap_key);
+  r = read_key(hctx, src_snap_key, &snap_meta);
+  if (r == -ENOENT) {
+    CLS_LOG(20, "cannot find existing snap with snap id = %" PRIu64,
+            src_snap_id.val);
+    return r;
+  }
+
+  if (cls::rbd::get_snap_namespace_type(snap_meta.snapshot_namespace) !=
+        cls::rbd::SNAPSHOT_NAMESPACE_TYPE_USER) {
+    // can only rename user snapshots
+    return -EINVAL;
+  }
+
+  snap_meta.name = dst_snap_name;
+  r = image::snapshot::write(hctx, src_snap_key, std::move(snap_meta));
+  if (r < 0) {
+    return r;
+  }
+
+  return 0;
+}
+
+/**
+ * Removes a snapshot from an rbd header.
+ *
+ * Input:
+ * @param snap_id the id of the snapshot to remove (uint64_t)
+ *
+ * Output:
+ * @returns 0 on success, negative error code on failure
+ */
+int snapshot_remove(cls_method_context_t hctx, bufferlist *in, bufferlist *out)
+{
+  snapid_t snap_id;
+
+  try {
+    auto iter = in->cbegin();
+    decode(snap_id, iter);
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+
+  CLS_LOG(20, "snapshot_remove id=%llu", (unsigned long long)snap_id.val);
+
+  // check if the key exists. we can't rely on remove_key doing this for
+  // us, since OMAPRMKEYS returns success if the key is not there.
+  // bug or feature? sounds like a bug, since tmap did not have this
+  // behavior, but cls_rgw may rely on it...
+  cls_rbd_snap snap;
+  string snapshot_key;
+  key_from_snap_id(snap_id, &snapshot_key);
+  int r = read_key(hctx, snapshot_key, &snap);
+  if (r == -ENOENT) {
+    return -ENOENT;
+  }
+
+  if (snap.protection_status != RBD_PROTECTION_STATUS_UNPROTECTED) {
+    return -EBUSY;
+  }
+
+  // snapshot is in-use by clone v2 child
+  if (snap.child_count > 0) {
+    return -EBUSY;
+  }
+
+  r = remove_key(hctx, snapshot_key);
+  if (r < 0) {
+    return r;
+  }
+
+  bool has_child_snaps = false;
+  bool has_trash_snaps = false;
+  auto remove_lambda = [snap_id, &has_child_snaps, &has_trash_snaps](
+      const cls_rbd_snap& snap_meta) {
+    if (snap_meta.id != snap_id) {
+      if (snap_meta.parent.pool_id != -1 || snap_meta.parent_overlap) {
+        has_child_snaps = true;
+      }
+
+      if (cls::rbd::get_snap_namespace_type(snap_meta.snapshot_namespace) ==
+            cls::rbd::SNAPSHOT_NAMESPACE_TYPE_TRASH) {
+        has_trash_snaps = true;
+      }
+    }
+    return 0;
+  };
+
+  r = image::snapshot::iterate(hctx, remove_lambda);
+  if (r < 0) {
+    return r;
+  }
+
+  cls_rbd_parent parent;
+  r = read_key(hctx, "parent", &parent);
+  if (r < 0 && r != -ENOENT) {
+    return r;
+  }
+
+  bool has_parent = (r >= 0 && parent.exists());
+  bool is_head_child = (has_parent && parent.head_overlap);
+  ceph_release_t require_osd_release = cls_get_required_osd_release(hctx);
+  if (has_parent && !is_head_child && !has_child_snaps &&
+      require_osd_release >= ceph_release_t::nautilus) {
+    // remove the unused parent image spec
+    r = remove_key(hctx, "parent");
+    if (r < 0 && r != -ENOENT) {
+      return r;
+    }
+  }
+
+  uint64_t op_features_mask = 0ULL;
+  if (!has_child_snaps && !is_head_child) {
+    // disable clone child op feature if no longer associated
+    op_features_mask |= RBD_OPERATION_FEATURE_CLONE_CHILD;
+  }
+  if (!has_trash_snaps) {
+    // remove the snap_trash op feature if not in-use by any other snapshots
+    op_features_mask |= RBD_OPERATION_FEATURE_SNAP_TRASH;
+  }
+
+  if (op_features_mask != 0ULL) {
+    r = image::set_op_features(hctx, 0, op_features_mask);
+    if (r < 0) {
+      return r;
+    }
+  }
+
+  return 0;
+}
+
+/**
+ * Moves a snapshot to the trash namespace.
+ *
+ * Input:
+ * @param snap_id the id of the snapshot to move to the trash (uint64_t)
+ *
+ * Output:
+ * @returns 0 on success, negative error code on failure
+ */
+int snapshot_trash_add(cls_method_context_t hctx, bufferlist *in,
+                       bufferlist *out)
+{
+  snapid_t snap_id;
+
+  try {
+    auto iter = in->cbegin();
+    decode(snap_id, iter);
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+
+  CLS_LOG(20, "snapshot_trash_add id=%" PRIu64, snap_id.val);
+
+  cls_rbd_snap snap;
+  std::string snapshot_key;
+  key_from_snap_id(snap_id, &snapshot_key);
+  int r = read_key(hctx, snapshot_key, &snap);
+  if (r == -ENOENT) {
+    return r;
+  }
+
+  if (snap.protection_status != RBD_PROTECTION_STATUS_UNPROTECTED) {
+    return -EBUSY;
+  }
+
+  auto snap_type = cls::rbd::get_snap_namespace_type(snap.snapshot_namespace);
+  if (snap_type == cls::rbd::SNAPSHOT_NAMESPACE_TYPE_TRASH) {
+    return -EEXIST;
+  }
+
+  // add snap_trash feature bit if not already enabled
+  r = image::set_op_features(hctx, RBD_OPERATION_FEATURE_SNAP_TRASH,
+                             RBD_OPERATION_FEATURE_SNAP_TRASH);
+  if (r < 0) {
+    return r;
+  }
+
+  snap.snapshot_namespace = cls::rbd::TrashSnapshotNamespace{snap_type,
+                                                             snap.name};
+  uuid_d uuid_gen;
+  uuid_gen.generate_random();
+  snap.name = uuid_gen.to_string();
+
+  r = image::snapshot::write(hctx, snapshot_key, std::move(snap));
+  if (r < 0) {
+    return r;
+  }
+
+  return 0;
+}
+
+/**
+ * Returns a uint64_t of all the features supported by this class.
+ */
+int get_all_features(cls_method_context_t hctx, bufferlist *in, bufferlist *out)
+{
+  uint64_t all_features = RBD_FEATURES_ALL;
+  encode(all_features, *out);
+  return 0;
+}
+
+/**
+ * "Copy up" data from the parent of a clone to the clone's object(s).
+ * Used for implementing copy-on-write for a clone image.  Client
+ * will pass down a chunk of data that fits completely within one
+ * clone block (one object), and is aligned (starts at beginning of block),
+ * but may be shorter (for non-full parent blocks).  The class method
+ * can't know the object size to validate the requested length,
+ * so it just writes the data as given if the child object doesn't
+ * already exist, and returns success if it does.
+ *
+ * Input:
+ * @param in bufferlist of data to write
+ *
+ * Output:
+ * @returns 0 on success, or if block already exists in child
+ *  negative error code on other error
+ */
+
+int copyup(cls_method_context_t hctx, bufferlist *in, bufferlist *out)
+{
+  // check for existence; if child object exists, just return success
+  if (cls_cxx_stat(hctx, NULL, NULL) == 0)
+    return 0;
+  CLS_LOG(20, "copyup: writing length %d\n", in->length());
+  return cls_cxx_write(hctx, 0, in->length(), in);
+}
+
+/**
+ * Input:
+ * @param extent_map map of extents to write
+ * @param data bufferlist of data to write
+ *
+ * Output:
+ * @returns 0 on success, or if block already exists in child
+ *  negative error code on other error
+ */
+
+int sparse_copyup(cls_method_context_t hctx, bufferlist *in, bufferlist *out)
+{
+  std::map<uint64_t, uint64_t> extent_map;
+  bufferlist data;
+
+  try {
+    auto iter = in->cbegin();
+    decode(extent_map, iter);
+    decode(data, iter);
+  } catch (const ceph::buffer::error &err) {
+    CLS_LOG(20, "sparse_copyup: invalid decode");
+    return -EINVAL;
+  }
+
+  int r = check_exists(hctx);
+  if (r == 0) {
+    return 0;
+  }
+
+  if (extent_map.empty()) {
+    CLS_LOG(20, "sparse_copyup: create empty object");
+    r = cls_cxx_create(hctx, true);
+    return r;
+  }
+
+  uint64_t data_offset = 0;
+  for (auto &it: extent_map) {
+    auto off = it.first;
+    auto len = it.second;
+
+    bufferlist tmpbl;
+    try {
+      tmpbl.substr_of(data, data_offset, len);
+    } catch (const ceph::buffer::error &err) {
+      CLS_LOG(20, "sparse_copyup: invalid data");
+      return -EINVAL;
+    }
+    data_offset += len;
+
+    CLS_LOG(20, "sparse_copyup: writing extent %" PRIu64 "~%" PRIu64 "\n", off,
+            len);
+    int r = cls_cxx_write(hctx, off, len, &tmpbl);
+    if (r < 0) {
+      CLS_ERR("sparse_copyup: error writing extent %" PRIu64 "~%" PRIu64 ": %s",
+              off, len, cpp_strerror(r).c_str());
+      return r;
+    }
+  }
+
+  return 0;
+}
+
+/************************ rbd_id object methods **************************/
+
+/**
+ * Input:
+ * @param in ignored
+ *
+ * Output:
+ * @param id the id stored in the object
+ * @returns 0 on success, negative error code on failure
+ */
+int get_id(cls_method_context_t hctx, bufferlist *in, bufferlist *out)
+{
+  uint64_t size;
+  int r = cls_cxx_stat(hctx, &size, NULL);
+  if (r < 0)
+    return r;
+
+  if (size == 0)
+    return -ENOENT;
+
+  bufferlist read_bl;
+  r = cls_cxx_read(hctx, 0, size, &read_bl);
+  if (r < 0) {
+    CLS_ERR("get_id: could not read id: %s", cpp_strerror(r).c_str());
+    return r;
+  }
+
+  string id;
+  try {
+    auto iter = read_bl.cbegin();
+    decode(id, iter);
+  } catch (const ceph::buffer::error &err) {
+    return -EIO;
+  }
+
+  encode(id, *out);
+  return 0;
+}
+
+/**
+ * Set the id of an image. The object must already exist.
+ *
+ * Input:
+ * @param id the id of the image, as an alpha-numeric string
+ *
+ * Output:
+ * @returns 0 on success, -EEXIST if the atomic create fails,
+ *          negative error code on other error
+ */
+int set_id(cls_method_context_t hctx, bufferlist *in, bufferlist *out)
+{
+  int r = check_exists(hctx);
+  if (r < 0)
+    return r;
+
+  string id;
+  try {
+    auto iter = in->cbegin();
+    decode(id, iter);
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+
+  if (!is_valid_id(id)) {
+    CLS_ERR("set_id: invalid id '%s'", id.c_str());
+    return -EINVAL;
+  }
+
+  uint64_t size;
+  r = cls_cxx_stat(hctx, &size, NULL);
+  if (r < 0)
+    return r;
+  if (size != 0)
+    return -EEXIST;
+
+  CLS_LOG(20, "set_id: id=%s", id.c_str());
+
+  bufferlist write_bl;
+  encode(id, write_bl);
+  return cls_cxx_write(hctx, 0, write_bl.length(), &write_bl);
+}
+
+/**
+ * Update the access timestamp of an image
+ *
+ * Input:
+ * @param none
+ *
+ * Output:
+ * @returns 0 on success, negative error code on other error
+ */
+int set_access_timestamp(cls_method_context_t hctx, bufferlist *in, bufferlist *out)
+{
+   int r = check_exists(hctx);
+   if(r < 0)
+     return r;
+   
+   utime_t timestamp = ceph_clock_now();
+   r = write_key(hctx, "access_timestamp", timestamp);
+   if(r < 0) {
+     CLS_ERR("error setting access_timestamp");
+     return r;
+   }
+
+   return 0;
+}
+
+/**
+ * Update the modify timestamp of an image
+ *
+ * Input:
+ * @param none
+ *
+ * Output:
+ * @returns 0 on success, negative error code on other error
+ */
+
+int set_modify_timestamp(cls_method_context_t hctx, bufferlist *in, bufferlist *out)
+{
+   int r = check_exists(hctx);
+   if(r < 0)
+     return r;
+   
+   utime_t timestamp = ceph_clock_now();
+   r = write_key(hctx, "modify_timestamp", timestamp);
+   if(r < 0) {
+     CLS_ERR("error setting modify_timestamp");
+     return r;
+   }
+
+   return 0;
+}
+
+
+
+/*********************** methods for rbd_directory ***********************/
+
+static const string dir_key_for_id(const string &id)
+{
+  return RBD_DIR_ID_KEY_PREFIX + id;
+}
+
+static const string dir_key_for_name(const string &name)
+{
+  return RBD_DIR_NAME_KEY_PREFIX + name;
+}
+
+static const string dir_name_from_key(const string &key)
+{
+  return key.substr(strlen(RBD_DIR_NAME_KEY_PREFIX));
+}
+
+static int dir_add_image_helper(cls_method_context_t hctx,
+				const string &name, const string &id,
+				bool check_for_unique_id)
+{
+  if (!name.size() || !is_valid_id(id)) {
+    CLS_ERR("dir_add_image_helper: invalid name '%s' or id '%s'",
+	    name.c_str(), id.c_str());
+    return -EINVAL;
+  }
+
+  CLS_LOG(20, "dir_add_image_helper name=%s id=%s", name.c_str(), id.c_str());
+
+  string tmp;
+  string name_key = dir_key_for_name(name);
+  string id_key = dir_key_for_id(id);
+  int r = read_key(hctx, name_key, &tmp);
+  if (r != -ENOENT) {
+    CLS_LOG(10, "name already exists");
+    return -EEXIST;
+  }
+  r = read_key(hctx, id_key, &tmp);
+  if (r != -ENOENT && check_for_unique_id) {
+    CLS_LOG(10, "id already exists");
+    return -EBADF;
+  }
+  bufferlist id_bl, name_bl;
+  encode(id, id_bl);
+  encode(name, name_bl);
+  map<string, bufferlist> omap_vals;
+  omap_vals[name_key] = id_bl;
+  omap_vals[id_key] = name_bl;
+  return cls_cxx_map_set_vals(hctx, &omap_vals);
+}
+
+static int dir_remove_image_helper(cls_method_context_t hctx,
+				   const string &name, const string &id)
+{
+  CLS_LOG(20, "dir_remove_image_helper name=%s id=%s",
+	  name.c_str(), id.c_str());
+
+  string stored_name, stored_id;
+  string name_key = dir_key_for_name(name);
+  string id_key = dir_key_for_id(id);
+  int r = read_key(hctx, name_key, &stored_id);
+  if (r < 0) {
+    if (r != -ENOENT)
+      CLS_ERR("error reading name to id mapping: %s", cpp_strerror(r).c_str());
+    return r;
+  }
+  r = read_key(hctx, id_key, &stored_name);
+  if (r < 0) {
+    CLS_ERR("error reading id to name mapping: %s", cpp_strerror(r).c_str());
+    return r;
+  }
+
+  // check if this op raced with a rename
+  if (stored_name != name || stored_id != id) {
+    CLS_ERR("stored name '%s' and id '%s' do not match args '%s' and '%s'",
+	    stored_name.c_str(), stored_id.c_str(), name.c_str(), id.c_str());
+    return -ESTALE;
+  }
+
+  r = cls_cxx_map_remove_key(hctx, name_key);
+  if (r < 0) {
+    CLS_ERR("error removing name: %s", cpp_strerror(r).c_str());
+    return r;
+  }
+
+  r = cls_cxx_map_remove_key(hctx, id_key);
+  if (r < 0) {
+    CLS_ERR("error removing id: %s", cpp_strerror(r).c_str());
+    return r;
+  }
+
+  return 0;
+}
+
+/**
+ * Rename an image in the directory, updating both indexes
+ * atomically. This can't be done from the client calling
+ * dir_add_image and dir_remove_image in one transaction because the
+ * results of the first method are not visibale to later steps.
+ *
+ * Input:
+ * @param src original name of the image
+ * @param dest new name of the image
+ * @param id the id of the image
+ *
+ * Output:
+ * @returns -ESTALE if src and id do not map to each other
+ * @returns -ENOENT if src or id are not in the directory
+ * @returns -EEXIST if dest already exists
+ * @returns 0 on success, negative error code on failure
+ */
+int dir_rename_image(cls_method_context_t hctx, bufferlist *in, bufferlist *out)
+{
+  string src, dest, id;
+  try {
+    auto iter = in->cbegin();
+    decode(src, iter);
+    decode(dest, iter);
+    decode(id, iter);
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+
+  int r = dir_remove_image_helper(hctx, src, id);
+  if (r < 0)
+    return r;
+  // ignore duplicate id because the result of
+  // remove_image_helper is not visible yet
+  return dir_add_image_helper(hctx, dest, id, false);
+}
+
+/**
+ * Get the id of an image given its name.
+ *
+ * Input:
+ * @param name the name of the image
+ *
+ * Output:
+ * @param id the id of the image
+ * @returns 0 on success, negative error code on failure
+ */
+int dir_get_id(cls_method_context_t hctx, bufferlist *in, bufferlist *out)
+{
+  string name;
+
+  try {
+    auto iter = in->cbegin();
+    decode(name, iter);
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+
+  CLS_LOG(20, "dir_get_id: name=%s", name.c_str());
+
+  string id;
+  int r = read_key(hctx, dir_key_for_name(name), &id);
+  if (r < 0) {
+    if (r != -ENOENT)
+      CLS_ERR("error reading id for name '%s': %s", name.c_str(), cpp_strerror(r).c_str());
+    return r;
+  }
+  encode(id, *out);
+  return 0;
+}
+
+/**
+ * Get the name of an image given its id.
+ *
+ * Input:
+ * @param id the id of the image
+ *
+ * Output:
+ * @param name the name of the image
+ * @returns 0 on success, negative error code on failure
+ */
+int dir_get_name(cls_method_context_t hctx, bufferlist *in, bufferlist *out)
+{
+  string id;
+
+  try {
+    auto iter = in->cbegin();
+    decode(id, iter);
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+
+  CLS_LOG(20, "dir_get_name: id=%s", id.c_str());
+
+  string name;
+  int r = read_key(hctx, dir_key_for_id(id), &name);
+  if (r < 0) {
+    if (r != -ENOENT) {
+      CLS_ERR("error reading name for id '%s': %s", id.c_str(),
+              cpp_strerror(r).c_str());
+    }
+    return r;
+  }
+  encode(name, *out);
+  return 0;
+}
+
+/**
+ * List the names and ids of the images in the directory, sorted by
+ * name.
+ *
+ * Input:
+ * @param start_after which name to begin listing after
+ *        (use the empty string to start at the beginning)
+ * @param max_return the maximum number of names to list
+ *
+ * Output:
+ * @param images map from name to id of up to max_return images
+ * @returns 0 on success, negative error code on failure
+ */
+int dir_list(cls_method_context_t hctx, bufferlist *in, bufferlist *out)
+{
+  string start_after;
+  uint64_t max_return;
+
+  try {
+    auto iter = in->cbegin();
+    decode(start_after, iter);
+    decode(max_return, iter);
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+
+  int max_read = RBD_MAX_KEYS_READ;
+  map<string, string> images;
+  string last_read = dir_key_for_name(start_after);
+  bool more = true;
+
+  while (more && images.size() < max_return) {
+    map<string, bufferlist> vals;
+    CLS_LOG(20, "last_read = '%s'", last_read.c_str());
+    int r = cls_cxx_map_get_vals(hctx, last_read, RBD_DIR_NAME_KEY_PREFIX,
+                                 max_read, &vals, &more);
+    if (r < 0) {
+      if (r != -ENOENT) {
+        CLS_ERR("error reading directory by name: %s", cpp_strerror(r).c_str());
+      }
+      return r;
+    }
+
+    for (auto it = vals.begin(); it != vals.end(); ++it) {
+      string id;
+      auto iter = it->second.cbegin();
+      try {
+	decode(id, iter);
+      } catch (const ceph::buffer::error &err) {
+	CLS_ERR("could not decode id of image '%s'", it->first.c_str());
+	return -EIO;
+      }
+      CLS_LOG(20, "adding '%s' -> '%s'", dir_name_from_key(it->first).c_str(), id.c_str());
+      images[dir_name_from_key(it->first)] = id;
+      if (images.size() >= max_return)
+	break;
+    }
+    if (!vals.empty()) {
+      last_read = dir_key_for_name(images.rbegin()->first);
+    }
+  }
+
+  encode(images, *out);
+
+  return 0;
+}
+
+/**
+ * Add an image to the rbd directory. Creates the directory object if
+ * needed, and updates the index from id to name and name to id.
+ *
+ * Input:
+ * @param name the name of the image
+ * @param id the id of the image
+ *
+ * Output:
+ * @returns -EEXIST if the image name is already in the directory
+ * @returns -EBADF if the image id is already in the directory
+ * @returns 0 on success, negative error code on failure
+ */
+int dir_add_image(cls_method_context_t hctx, bufferlist *in, bufferlist *out)
+{
+  int r = cls_cxx_create(hctx, false);
+  if (r < 0) {
+    CLS_ERR("could not create directory: %s", cpp_strerror(r).c_str());
+    return r;
+  }
+
+  string name, id;
+  try {
+    auto iter = in->cbegin();
+    decode(name, iter);
+    decode(id, iter);
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+
+  return dir_add_image_helper(hctx, name, id, true);
+}
+
+/**
+ * Remove an image from the rbd directory.
+ *
+ * Input:
+ * @param name the name of the image
+ * @param id the id of the image
+ *
+ * Output:
+ * @returns -ESTALE if the name and id do not map to each other
+ * @returns 0 on success, negative error code on failure
+ */
+int dir_remove_image(cls_method_context_t hctx, bufferlist *in, bufferlist *out)
+{
+  string name, id;
+  try {
+    auto iter = in->cbegin();
+    decode(name, iter);
+    decode(id, iter);
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+
+  return dir_remove_image_helper(hctx, name, id);
+}
+
+/**
+ * Verify the current state of the directory
+ *
+ * Input:
+ * @param state the DirectoryState of the directory
+ *
+ * Output:
+ * @returns -ENOENT if the state does not match
+ * @returns 0 on success, negative error code on failure
+ */
+int dir_state_assert(cls_method_context_t hctx, bufferlist *in, bufferlist *out)
+{
+  cls::rbd::DirectoryState directory_state = cls::rbd::DIRECTORY_STATE_READY;
+  try {
+    auto iter = in->cbegin();
+    decode(directory_state, iter);
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+
+  cls::rbd::DirectoryState on_disk_directory_state = directory_state;
+  int r = read_key(hctx, "state", &on_disk_directory_state);
+  if (r < 0) {
+    return r;
+  }
+
+  if (directory_state != on_disk_directory_state) {
+    return -ENOENT;
+  }
+  return 0;
+}
+
+/**
+ * Set the current state of the directory
+ *
+ * Input:
+ * @param state the DirectoryState of the directory
+ *
+ * Output:
+ * @returns -ENOENT if the state does not match
+ * @returns 0 on success, negative error code on failure
+ */
+int dir_state_set(cls_method_context_t hctx, bufferlist *in, bufferlist *out)
+{
+  cls::rbd::DirectoryState directory_state;
+  try {
+    auto iter = in->cbegin();
+    decode(directory_state, iter);
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+
+  int r = check_exists(hctx);
+  if (r < 0 && r != -ENOENT) {
+    return r;
+  }
+
+  switch (directory_state) {
+  case cls::rbd::DIRECTORY_STATE_READY:
+    break;
+  case cls::rbd::DIRECTORY_STATE_ADD_DISABLED:
+    {
+      if (r == -ENOENT) {
+        return r;
+      }
+
+      // verify that the directory is empty
+      std::map<std::string, bufferlist> vals;
+      bool more;
+      r = cls_cxx_map_get_vals(hctx, RBD_DIR_NAME_KEY_PREFIX,
+                               RBD_DIR_NAME_KEY_PREFIX, 1, &vals, &more);
+      if (r < 0) {
+        return r;
+      } else if (!vals.empty()) {
+        return -EBUSY;
+      }
+    }
+    break;
+  default:
+    return -EINVAL;
+  }
+
+  r = write_key(hctx, "state", directory_state);
+  if (r < 0) {
+    return r;
+  }
+
+  return 0;
+}
+
+int object_map_read(cls_method_context_t hctx, BitVector<2> &object_map)
+{
+  uint64_t size;
+  int r = cls_cxx_stat(hctx, &size, NULL);
+  if (r < 0) {
+    return r;
+  }
+  if (size == 0) {
+    return -ENOENT;
+  }
+
+  bufferlist bl;
+  r = cls_cxx_read(hctx, 0, size, &bl);
+  if (r < 0) {
+   return r;
+  }
+
+  try {
+    auto iter = bl.cbegin();
+    decode(object_map, iter);
+  } catch (const ceph::buffer::error &err) {
+    CLS_ERR("failed to decode object map: %s", err.what());
+    return -EINVAL;
+  }
+  return 0;
+}
+
+/**
+ * Load an rbd image's object map
+ *
+ * Input:
+ * none
+ *
+ * Output:
+ * @param object map bit vector
+ * @returns 0 on success, negative error code on failure
+ */
+int object_map_load(cls_method_context_t hctx, bufferlist *in, bufferlist *out)
+{
+  BitVector<2> object_map;
+  int r = object_map_read(hctx, object_map);
+  if (r < 0) {
+    return r;
+  }
+
+  object_map.set_crc_enabled(false);
+  encode(object_map, *out);
+  return 0;
+}
+
+/**
+ * Save an rbd image's object map
+ *
+ * Input:
+ * @param object map bit vector
+ *
+ * Output:
+ * @returns 0 on success, negative error code on failure
+ */
+int object_map_save(cls_method_context_t hctx, bufferlist *in, bufferlist *out)
+{
+  BitVector<2> object_map;
+  try {
+    auto iter = in->cbegin();
+    decode(object_map, iter);
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+
+  object_map.set_crc_enabled(true);
+
+  bufferlist bl;
+  encode(object_map, bl);
+  CLS_LOG(20, "object_map_save: object size=%" PRIu64 ", byte size=%u",
+	  object_map.size(), bl.length());
+  return cls_cxx_write_full(hctx, &bl);
+}
+
+/**
+ * Resize an rbd image's object map
+ *
+ * Input:
+ * @param object_count the max number of objects in the image
+ * @param default_state the default state of newly created objects
+ *
+ * Output:
+ * @returns 0 on success, negative error code on failure
+ */
+int object_map_resize(cls_method_context_t hctx, bufferlist *in, bufferlist *out)
+{
+  uint64_t object_count;
+  uint8_t default_state;
+  try {
+    auto iter = in->cbegin();
+    decode(object_count, iter);
+    decode(default_state, iter);
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+
+  // protect against excessive memory requirements
+  if (object_count > cls::rbd::MAX_OBJECT_MAP_OBJECT_COUNT) {
+    CLS_ERR("object map too large: %" PRIu64, object_count);
+    return -EINVAL;
+  }
+
+  BitVector<2> object_map;
+  int r = object_map_read(hctx, object_map);
+  if ((r < 0) && (r != -ENOENT)) {
+    return r;
+  }
+
+  size_t orig_object_map_size = object_map.size();
+  if (object_count < orig_object_map_size) {
+    auto it = object_map.begin() + object_count;
+    auto end_it = object_map.end() ;
+    uint64_t i = object_count;
+    for (; it != end_it; ++it, ++i) {
+      if (*it != default_state) {
+	CLS_ERR("object map indicates object still exists: %" PRIu64, i);
+	return -ESTALE;
+      }
+    }
+    object_map.resize(object_count);
+  } else if (object_count > orig_object_map_size) {
+    object_map.resize(object_count);
+    auto it = object_map.begin() + orig_object_map_size;
+    auto end_it = object_map.end();
+    for (; it != end_it; ++it) {
+      *it = default_state;
+    }
+  }
+
+  bufferlist map;
+  encode(object_map, map);
+  CLS_LOG(20, "object_map_resize: object size=%" PRIu64 ", byte size=%u",
+	  object_count, map.length());
+  return cls_cxx_write_full(hctx, &map);
+}
+
+/**
+ * Update an rbd image's object map
+ *
+ * Input:
+ * @param start_object_no the start object iterator
+ * @param end_object_no the end object iterator
+ * @param new_object_state the new object state
+ * @param current_object_state optional current object state filter
+ *
+ * Output:
+ * @returns 0 on success, negative error code on failure
+ */
+int object_map_update(cls_method_context_t hctx, bufferlist *in, bufferlist *out)
+{
+  uint64_t start_object_no;
+  uint64_t end_object_no;
+  uint8_t new_object_state;
+  boost::optional<uint8_t> current_object_state;
+  try {
+    auto iter = in->cbegin();
+    decode(start_object_no, iter);
+    decode(end_object_no, iter);
+    decode(new_object_state, iter);
+    decode(current_object_state, iter);
+  } catch (const ceph::buffer::error &err) {
+    CLS_ERR("failed to decode message");
+    return -EINVAL;
+  }
+
+  uint64_t size;
+  int r = cls_cxx_stat(hctx, &size, NULL);
+  if (r < 0) {
+    return r;
+  }
+
+  BitVector<2> object_map;
+  bufferlist header_bl;
+  r = cls_cxx_read2(hctx, 0, object_map.get_header_length(), &header_bl,
+                    CEPH_OSD_OP_FLAG_FADVISE_WILLNEED);
+  if (r < 0) {
+    CLS_ERR("object map header read failed");
+    return r;
+  }
+
+  try {
+    auto it = header_bl.cbegin();
+    object_map.decode_header(it);
+  } catch (const ceph::buffer::error &err) {
+    CLS_ERR("failed to decode object map header: %s", err.what());
+    return -EINVAL;
+  }
+
+  uint64_t object_byte_offset;
+  uint64_t byte_length;
+  object_map.get_header_crc_extents(&object_byte_offset, &byte_length);
+
+  bufferlist footer_bl;
+  r = cls_cxx_read2(hctx, object_byte_offset, byte_length, &footer_bl,
+                    CEPH_OSD_OP_FLAG_FADVISE_WILLNEED);
+  if (r < 0) {
+    CLS_ERR("object map footer read header CRC failed");
+    return r;
+  }
+
+  try {
+    auto it = footer_bl.cbegin();
+    object_map.decode_header_crc(it);
+  } catch (const ceph::buffer::error &err) {
+    CLS_ERR("failed to decode object map header CRC: %s", err.what());
+  }
+
+  if (start_object_no >= end_object_no || end_object_no > object_map.size()) {
+    return -ERANGE;
+  }
+
+  uint64_t object_count = end_object_no - start_object_no;
+  object_map.get_data_crcs_extents(start_object_no, object_count,
+                                   &object_byte_offset, &byte_length);
+  const auto footer_object_offset = object_byte_offset;
+
+  footer_bl.clear();
+  r = cls_cxx_read2(hctx, object_byte_offset, byte_length, &footer_bl,
+                    CEPH_OSD_OP_FLAG_FADVISE_WILLNEED);
+  if (r < 0) {
+    CLS_ERR("object map footer read data CRCs failed");
+    return r;
+  }
+
+  try {
+    auto it = footer_bl.cbegin();
+    object_map.decode_data_crcs(it, start_object_no);
+  } catch (const ceph::buffer::error &err) {
+    CLS_ERR("failed to decode object map data CRCs: %s", err.what());
+  }
+
+  uint64_t data_byte_offset;
+  object_map.get_data_extents(start_object_no, object_count,
+                              &data_byte_offset, &object_byte_offset,
+                              &byte_length);
+
+  bufferlist data_bl;
+  r = cls_cxx_read2(hctx, object_byte_offset, byte_length, &data_bl,
+                    CEPH_OSD_OP_FLAG_FADVISE_WILLNEED);
+  if (r < 0) {
+    CLS_ERR("object map data read failed");
+    return r;
+  }
+
+  try {
+    auto it = data_bl.cbegin();
+    object_map.decode_data(it, data_byte_offset);
+  } catch (const ceph::buffer::error &err) {
+    CLS_ERR("failed to decode data chunk [%" PRIu64 "]: %s",
+	    data_byte_offset, err.what());
+    return -EINVAL;
+  }
+
+  bool updated = false;
+  auto it = object_map.begin() + start_object_no;
+  auto end_it = object_map.begin() + end_object_no;
+  for (; it != end_it; ++it) {
+    uint8_t state = *it;
+    if ((!current_object_state || state == *current_object_state ||
+        (*current_object_state == OBJECT_EXISTS &&
+         state == OBJECT_EXISTS_CLEAN)) && state != new_object_state) {
+      *it = new_object_state;
+      updated = true;
+    }
+  }
+
+  if (updated) {
+    CLS_LOG(20, "object_map_update: %" PRIu64 "~%" PRIu64 " -> %" PRIu64,
+	    data_byte_offset, byte_length, object_byte_offset);
+
+    bufferlist data_bl;
+    object_map.encode_data(data_bl, data_byte_offset, byte_length);
+    r = cls_cxx_write2(hctx, object_byte_offset, data_bl.length(), &data_bl,
+                       CEPH_OSD_OP_FLAG_FADVISE_WILLNEED);
+    if (r < 0) {
+      CLS_ERR("failed to write object map header: %s", cpp_strerror(r).c_str());
+      return r;
+    }
+
+    footer_bl.clear();
+    object_map.encode_data_crcs(footer_bl, start_object_no, object_count);
+    r = cls_cxx_write2(hctx, footer_object_offset, footer_bl.length(),
+		       &footer_bl, CEPH_OSD_OP_FLAG_FADVISE_WILLNEED);
+    if (r < 0) {
+      CLS_ERR("failed to write object map footer: %s", cpp_strerror(r).c_str());
+      return r;
+    }
+  } else {
+    CLS_LOG(20, "object_map_update: no update necessary");
+  }
+
+  return 0;
+}
+
+/**
+ * Mark all _EXISTS objects as _EXISTS_CLEAN so future writes to the
+ * image HEAD can be tracked.
+ *
+ * Input:
+ * none
+ *
+ * Output:
+ * @returns 0 on success, negative error code on failure
+ */
+int object_map_snap_add(cls_method_context_t hctx, bufferlist *in,
+                        bufferlist *out)
+{
+  BitVector<2> object_map;
+  int r = object_map_read(hctx, object_map);
+  if (r < 0) {
+    return r;
+  }
+
+  bool updated = false;
+  auto it = object_map.begin();
+  auto end_it = object_map.end();
+  for (; it != end_it; ++it) {
+    if (*it == OBJECT_EXISTS) {
+      *it = OBJECT_EXISTS_CLEAN;
+      updated = true;
+    }
+  }
+
+  if (updated) {
+    bufferlist bl;
+    encode(object_map, bl);
+    r = cls_cxx_write_full(hctx, &bl);
+  }
+  return r;
+}
+
+/**
+ * Mark all _EXISTS_CLEAN objects as _EXISTS in the current object map
+ * if the provided snapshot object map object is marked as _EXISTS.
+ *
+ * Input:
+ * @param snapshot object map bit vector
+ *
+ * Output:
+ * @returns 0 on success, negative error code on failure
+ */
+int object_map_snap_remove(cls_method_context_t hctx, bufferlist *in,
+                           bufferlist *out)
+{
+  BitVector<2> src_object_map;
+  try {
+    auto iter = in->cbegin();
+    decode(src_object_map, iter);
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+
+  BitVector<2> dst_object_map;
+  int r = object_map_read(hctx, dst_object_map);
+  if (r < 0) {
+    return r;
+  }
+
+  bool updated = false;
+  auto src_it = src_object_map.begin();
+  auto dst_it = dst_object_map.begin();
+  auto dst_it_end = dst_object_map.end();
+  uint64_t i = 0;
+  for (; dst_it != dst_it_end; ++dst_it) {
+    if (*dst_it == OBJECT_EXISTS_CLEAN &&
+        (i >= src_object_map.size() || *src_it == OBJECT_EXISTS)) {
+      *dst_it = OBJECT_EXISTS;
+      updated = true;
+    }
+    if (i < src_object_map.size())
+      ++src_it;
+    ++i;
+  }
+
+  if (updated) {
+    bufferlist bl;
+    encode(dst_object_map, bl);
+    r = cls_cxx_write_full(hctx, &bl);
+  }
+  return r;
+}
+
+static const string metadata_key_for_name(const string &name)
+{
+  return RBD_METADATA_KEY_PREFIX + name;
+}
+
+static const string metadata_name_from_key(const string &key)
+{
+  return key.substr(strlen(RBD_METADATA_KEY_PREFIX));
+}
+
+/**
+ * Input:
+ * @param start_after which name to begin listing after
+ *        (use the empty string to start at the beginning)
+ * @param max_return the maximum number of names to list
+
+ * Output:
+ * @param value
+ * @returns 0 on success, negative error code on failure
+ */
+int metadata_list(cls_method_context_t hctx, bufferlist *in, bufferlist *out)
+{
+  string start_after;
+  uint64_t max_return;
+
+  try {
+    auto iter = in->cbegin();
+    decode(start_after, iter);
+    decode(max_return, iter);
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+
+  // TODO remove implicit support for zero during the N-release
+  if (max_return == 0) {
+    max_return = RBD_MAX_KEYS_READ;
+  }
+
+  map<string, bufferlist> data;
+  string last_read = metadata_key_for_name(start_after);
+  bool more = true;
+
+  while (more && data.size() < max_return) {
+    map<string, bufferlist> raw_data;
+    int max_read = std::min<uint64_t>(RBD_MAX_KEYS_READ, max_return - data.size());
+    int r = cls_cxx_map_get_vals(hctx, last_read, RBD_METADATA_KEY_PREFIX,
+                                 max_read, &raw_data, &more);
+    if (r < 0) {
+      if (r != -ENOENT) {
+        CLS_ERR("failed to read the vals off of disk: %s",
+                cpp_strerror(r).c_str());
+      }
+      return r;
+    }
+
+    for (auto& kv : raw_data) {
+      data[metadata_name_from_key(kv.first)].swap(kv.second);
+    }
+
+    if (!raw_data.empty()) {
+      last_read = raw_data.rbegin()->first;
+    }
+  }
+
+  encode(data, *out);
+  return 0;
+}
+
+/**
+ * Input:
+ * @param data <map(key, value)>
+ *
+ * Output:
+ * @returns 0 on success, negative error code on failure
+ */
+int metadata_set(cls_method_context_t hctx, bufferlist *in, bufferlist *out)
+{
+  map<string, bufferlist> data, raw_data;
+
+  auto iter = in->cbegin();
+  try {
+    decode(data, iter);
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+
+  for (auto it = data.begin(); it != data.end(); ++it) {
+    CLS_LOG(20, "metadata_set key=%s value=%.*s", it->first.c_str(),
+	    it->second.length(), it->second.c_str());
+    raw_data[metadata_key_for_name(it->first)].swap(it->second);
+  }
+  int r = cls_cxx_map_set_vals(hctx, &raw_data);
+  if (r < 0) {
+    CLS_ERR("error writing metadata: %s", cpp_strerror(r).c_str());
+    return r;
+  }
+
+  return 0;
+}
+
+/**
+ * Input:
+ * @param key
+ *
+ * Output:
+ * @returns 0 on success, negative error code on failure
+ */
+int metadata_remove(cls_method_context_t hctx, bufferlist *in, bufferlist *out)
+{
+  string key;
+
+  auto iter = in->cbegin();
+  try {
+    decode(key, iter);
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+
+  CLS_LOG(20, "metadata_remove key=%s", key.c_str());
+
+  int r = cls_cxx_map_remove_key(hctx, metadata_key_for_name(key));
+  if (r < 0) {
+    CLS_ERR("error removing metadata: %s", cpp_strerror(r).c_str());
+    return r;
+  }
+
+  return 0;
+}
+
+/**
+ * Input:
+ * @param key
+ *
+ * Output:
+ * @param metadata value associated with the key
+ * @returns 0 on success, negative error code on failure
+ */
+int metadata_get(cls_method_context_t hctx, bufferlist *in, bufferlist *out)
+{
+  string key;
+  bufferlist value;
+
+  auto iter = in->cbegin();
+  try {
+    decode(key, iter);
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+
+  CLS_LOG(20, "metadata_get key=%s", key.c_str());
+
+  int r = cls_cxx_map_get_val(hctx, metadata_key_for_name(key), &value);
+  if (r < 0) {
+    if (r != -ENOENT)
+      CLS_ERR("error getting metadata: %s", cpp_strerror(r).c_str());
+    return r;
+  }
+
+  encode(value, *out);
+  return 0;
+}
+
+int snapshot_get_limit(cls_method_context_t hctx, bufferlist *in,
+		       bufferlist *out)
+{
+  uint64_t snap_limit;
+  int r = read_key(hctx, "snap_limit", &snap_limit);
+  if (r == -ENOENT) {
+    snap_limit = UINT64_MAX;
+  } else if (r < 0) {
+    CLS_ERR("error retrieving snapshot limit: %s", cpp_strerror(r).c_str());
+    return r;
+  }
+
+  CLS_LOG(20, "read snapshot limit %" PRIu64, snap_limit);
+  encode(snap_limit, *out);
+
+  return 0;
+}
+
+int snapshot_set_limit(cls_method_context_t hctx, bufferlist *in,
+		       bufferlist *out)
+{
+  int rc;
+  uint64_t new_limit;
+  bufferlist bl;
+  size_t snap_count = 0;
+
+  try {
+    auto iter = in->cbegin();
+    decode(new_limit, iter);
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+
+  if (new_limit == UINT64_MAX) {
+    CLS_LOG(20, "remove snapshot limit\n");
+    rc = cls_cxx_map_remove_key(hctx, "snap_limit");
+    return rc;
+  }
+
+  //try to read header as v1 format
+  rc = snap_read_header(hctx, bl);
+
+  // error when reading header
+  if (rc < 0 && rc != -EINVAL) {
+    return rc;
+  } else if (rc >= 0) {
+    // success, the image is v1 format
+    struct rbd_obj_header_ondisk *header;
+    header = (struct rbd_obj_header_ondisk *)bl.c_str();
+    snap_count = header->snap_count;
+  } else {
+    // else, the image is v2 format
+    int max_read = RBD_MAX_KEYS_READ;
+    string last_read = RBD_SNAP_KEY_PREFIX;
+    bool more;
+
+    do {
+      set<string> keys;
+      rc = cls_cxx_map_get_keys(hctx, last_read, max_read, &keys, &more);
+      if (rc < 0) {
+        CLS_ERR("error retrieving snapshots: %s", cpp_strerror(rc).c_str());
+        return rc;
+      }
+      for (auto& key : keys) {
+        if (key.find(RBD_SNAP_KEY_PREFIX) != 0)
+          break;
+        snap_count++;
+      }
+      if (!keys.empty())
+        last_read = *(keys.rbegin());
+    } while (more);
+  }
+
+  if (new_limit < snap_count) {
+    rc = -ERANGE;
+    CLS_LOG(10, "snapshot limit is less than the number of snapshots.\n");
+  } else {
+    CLS_LOG(20, "set snapshot limit to %" PRIu64 "\n", new_limit);
+    bl.clear();
+    encode(new_limit, bl);
+    rc = cls_cxx_map_set_val(hctx, "snap_limit", &bl);
+  }
+
+  return rc;
+}
+
+
+/**
+ * Input:
+ * @param snap id (uint64_t) parent snapshot id
+ * @param child spec (cls::rbd::ChildImageSpec) child image
+ *
+ * Output:
+ * @returns 0 on success, negative error code on failure
+ */
+int child_attach(cls_method_context_t hctx, bufferlist *in, bufferlist *out)
+{
+  uint64_t snap_id;
+  cls::rbd::ChildImageSpec child_image;
+  try {
+    auto it = in->cbegin();
+    decode(snap_id, it);
+    decode(child_image, it);
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+
+  CLS_LOG(20, "child_attach snap_id=%" PRIu64 ", child_pool_id=%" PRIi64 ", "
+              "child_image_id=%s", snap_id, child_image.pool_id,
+               child_image.image_id.c_str());
+
+  cls_rbd_snap snap;
+  std::string snapshot_key;
+  key_from_snap_id(snap_id, &snapshot_key);
+  int r = read_key(hctx, snapshot_key, &snap);
+  if (r < 0) {
+    return r;
+  }
+
+  if (cls::rbd::get_snap_namespace_type(snap.snapshot_namespace) ==
+        cls::rbd::SNAPSHOT_NAMESPACE_TYPE_TRASH) {
+    // cannot attach to a deleted snapshot
+    return -ENOENT;
+  }
+
+  auto children_key = image::snap_children_key_from_snap_id(snap_id);
+  cls::rbd::ChildImageSpecs child_images;
+  r = read_key(hctx, children_key, &child_images);
+  if (r < 0 && r != -ENOENT) {
+    CLS_ERR("error reading snapshot children: %s", cpp_strerror(r).c_str());
+    return r;
+  }
+
+  auto it = child_images.insert(child_image);
+  if (!it.second) {
+    // child already attached to the snapshot
+    return -EEXIST;
+  }
+
+  r = write_key(hctx, children_key, child_images);
+  if (r < 0) {
+    CLS_ERR("error writing snapshot children: %s", cpp_strerror(r).c_str());
+    return r;
+  }
+
+  ++snap.child_count;
+  r = image::snapshot::write(hctx, snapshot_key, std::move(snap));
+  if (r < 0) {
+    return r;
+  }
+
+  r = image::set_op_features(hctx, RBD_OPERATION_FEATURE_CLONE_PARENT,
+                             RBD_OPERATION_FEATURE_CLONE_PARENT);
+  if (r < 0) {
+    return r;
+  }
+
+  return 0;
+}
+
+/**
+ * Input:
+ * @param snap id (uint64_t) parent snapshot id
+ * @param child spec (cls::rbd::ChildImageSpec) child image
+ *
+ * Output:
+ * @returns 0 on success, negative error code on failure
+ */
+int child_detach(cls_method_context_t hctx, bufferlist *in, bufferlist *out)
+{
+  uint64_t snap_id;
+  cls::rbd::ChildImageSpec child_image;
+  try {
+    auto it = in->cbegin();
+    decode(snap_id, it);
+    decode(child_image, it);
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+
+  CLS_LOG(20, "child_detach snap_id=%" PRIu64 ", child_pool_id=%" PRIi64 ", "
+              "child_image_id=%s", snap_id, child_image.pool_id,
+               child_image.image_id.c_str());
+
+  cls_rbd_snap snap;
+  std::string snapshot_key;
+  key_from_snap_id(snap_id, &snapshot_key);
+  int r = read_key(hctx, snapshot_key, &snap);
+  if (r < 0) {
+    return r;
+  }
+
+  auto children_key = image::snap_children_key_from_snap_id(snap_id);
+  cls::rbd::ChildImageSpecs child_images;
+  r = read_key(hctx, children_key, &child_images);
+  if (r < 0 && r != -ENOENT) {
+    CLS_ERR("error reading snapshot children: %s", cpp_strerror(r).c_str());
+    return r;
+  }
+
+  if (snap.child_count != child_images.size()) {
+    // children and reference count don't match
+    CLS_ERR("children reference count mismatch: %" PRIu64, snap_id);
+    return -EINVAL;
+  }
+
+  if (child_images.erase(child_image) == 0) {
+    // child not attached to the snapshot
+    return -ENOENT;
+  }
+
+  if (child_images.empty()) {
+    r = remove_key(hctx, children_key);
+  } else {
+    r = write_key(hctx, children_key, child_images);
+    if (r < 0) {
+      CLS_ERR("error writing snapshot children: %s", cpp_strerror(r).c_str());
+      return r;
+    }
+  }
+
+  --snap.child_count;
+  r = image::snapshot::write(hctx, snapshot_key, std::move(snap));
+  if (r < 0) {
+    return r;
+  }
+
+  if (snap.child_count == 0) {
+    auto clone_in_use_lambda = [snap_id](const cls_rbd_snap& snap_meta) {
+      if (snap_meta.id != snap_id && snap_meta.child_count > 0) {
+        return -EEXIST;
+      }
+      return 0;
+    };
+
+    r = image::snapshot::iterate(hctx, clone_in_use_lambda);
+    if (r < 0 && r != -EEXIST) {
+      return r;
+    }
+
+    if (r != -EEXIST) {
+      // remove the clone_v2 op feature if not in-use by any other snapshots
+      r = image::set_op_features(hctx, 0, RBD_OPERATION_FEATURE_CLONE_PARENT);
+      if (r < 0) {
+        return r;
+      }
+    }
+  }
+
+  return 0;
+}
+
+/**
+ * Input:
+ * @param snap id (uint64_t) parent snapshot id
+ *
+ * Output:
+ * @param (cls::rbd::ChildImageSpecs) child images
+ * @returns 0 on success, negative error code on failure
+ */
+int children_list(cls_method_context_t hctx, bufferlist *in, bufferlist *out)
+{
+  uint64_t snap_id;
+  try {
+    auto it = in->cbegin();
+    decode(snap_id, it);
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+
+  CLS_LOG(20, "child_detach snap_id=%" PRIu64, snap_id);
+
+  cls_rbd_snap snap;
+  std::string snapshot_key;
+  key_from_snap_id(snap_id, &snapshot_key);
+  int r = read_key(hctx, snapshot_key, &snap);
+  if (r < 0) {
+    return r;
+  }
+
+  auto children_key = image::snap_children_key_from_snap_id(snap_id);
+  cls::rbd::ChildImageSpecs child_images;
+  r = read_key(hctx, children_key, &child_images);
+  if (r == -ENOENT) {
+    return r;
+  } else if (r < 0) {
+    CLS_ERR("error reading snapshot children: %s", cpp_strerror(r).c_str());
+    return r;
+  }
+
+  encode(child_images, *out);
+  return 0;
+}
+
+/**
+ * Set image migration.
+ *
+ * Input:
+ * @param migration_spec (cls::rbd::MigrationSpec) image migration spec
+ *
+ * Output:
+ *
+ * @returns 0 on success, negative error code on failure
+ */
+int migration_set(cls_method_context_t hctx, bufferlist *in, bufferlist *out) {
+  cls::rbd::MigrationSpec migration_spec;
+  try {
+    auto it = in->cbegin();
+    decode(migration_spec, it);
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+
+  int r = image::set_migration(hctx, migration_spec, true);
+  if (r < 0) {
+    return r;
+  }
+
+  return 0;
+}
+
+/**
+ * Set image migration state.
+ *
+ * Input:
+ * @param state (cls::rbd::MigrationState) migration state
+ * @param description (std::string) migration state description
+ *
+ * Output:
+ *
+ * @returns 0 on success, negative error code on failure
+ */
+int migration_set_state(cls_method_context_t hctx, bufferlist *in,
+                        bufferlist *out) {
+  cls::rbd::MigrationState state;
+  std::string description;
+  try {
+    auto it = in->cbegin();
+    decode(state, it);
+    decode(description, it);
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+
+  cls::rbd::MigrationSpec migration_spec;
+  int r = image::read_migration(hctx, &migration_spec);
+  if (r < 0) {
+    return r;
+  }
+
+  migration_spec.state = state;
+  migration_spec.state_description = description;
+
+  r = image::set_migration(hctx, migration_spec, false);
+  if (r < 0) {
+    return r;
+  }
+
+  return 0;
+}
+
+/**
+ * Get image migration spec.
+ *
+ * Input:
+ *
+ * Output:
+ * @param migration_spec (cls::rbd::MigrationSpec) image migration spec
+ *
+ * @returns 0 on success, negative error code on failure
+ */
+int migration_get(cls_method_context_t hctx, bufferlist *in, bufferlist *out) {
+  cls::rbd::MigrationSpec migration_spec;
+  int r = image::read_migration(hctx, &migration_spec);
+  if (r < 0) {
+    return r;
+  }
+
+  encode(migration_spec, *out);
+
+  return 0;
+}
+
+/**
+ * Remove image migration spec.
+ *
+ * Input:
+ *
+ * Output:
+ *
+ * @returns 0 on success, negative error code on failure
+ */
+int migration_remove(cls_method_context_t hctx, bufferlist *in,
+                     bufferlist *out) {
+  int r = image::remove_migration(hctx);
+  if (r < 0) {
+    return r;
+  }
+
+  return 0;
+}
+
+/**
+ * Ensure writer snapc state
+ *
+ * Input:
+ * @param snap id (uint64_t) snap context sequence id
+ * @param state (cls::rbd::AssertSnapcSeqState) snap context state
+ *
+ * Output:
+ * @returns -ERANGE if assertion fails
+ * @returns 0 on success, negative error code on failure
+ */
+int assert_snapc_seq(cls_method_context_t hctx, bufferlist *in,
+                     bufferlist *out)
+{
+  uint64_t snapc_seq;
+  cls::rbd::AssertSnapcSeqState state;
+  try {
+    auto it = in->cbegin();
+    decode(snapc_seq, it);
+    decode(state, it);
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+
+  uint64_t snapset_seq;
+  int r = cls_get_snapset_seq(hctx, &snapset_seq);
+  if (r < 0 && r != -ENOENT) {
+    return r;
+  }
+
+  switch (state) {
+  case cls::rbd::ASSERT_SNAPC_SEQ_GT_SNAPSET_SEQ:
+    return (r == -ENOENT || snapc_seq > snapset_seq) ? 0 : -ERANGE;
+  case cls::rbd::ASSERT_SNAPC_SEQ_LE_SNAPSET_SEQ:
+    return (r == -ENOENT || snapc_seq > snapset_seq) ? -ERANGE : 0;
+  default:
+    return -EOPNOTSUPP;
+  }
+}
+
+/****************************** Old format *******************************/
+
+int old_snapshots_list(cls_method_context_t hctx, bufferlist *in, bufferlist *out)
+{
+  bufferlist bl;
+  struct rbd_obj_header_ondisk *header;
+  int rc = snap_read_header(hctx, bl);
+  if (rc < 0)
+    return rc;
+
+  header = (struct rbd_obj_header_ondisk *)bl.c_str();
+  bufferptr p(header->snap_names_len);
+  char *buf = (char *)header;
+  char *name = buf + sizeof(*header) + header->snap_count * sizeof(struct rbd_obj_snap_ondisk);
+  char *end = name + header->snap_names_len;
+  memcpy(p.c_str(),
+         buf + sizeof(*header) + header->snap_count * sizeof(struct rbd_obj_snap_ondisk),
+         header->snap_names_len);
+
+  encode(header->snap_seq, *out);
+  encode(header->snap_count, *out);
+
+  for (unsigned i = 0; i < header->snap_count; i++) {
+    string s = name;
+    encode(header->snaps[i].id, *out);
+    encode(header->snaps[i].image_size, *out);
+    encode(s, *out);
+
+    name += strlen(name) + 1;
+    if (name > end)
+      return -EIO;
+  }
+
+  return 0;
+}
+
+int old_snapshot_add(cls_method_context_t hctx, bufferlist *in, bufferlist *out)
+{
+  bufferlist bl;
+  struct rbd_obj_header_ondisk *header;
+  bufferlist newbl;
+  bufferptr header_bp(sizeof(*header));
+  struct rbd_obj_snap_ondisk *new_snaps;
+
+  int rc = snap_read_header(hctx, bl);
+  if (rc < 0)
+    return rc;
+
+  header = (struct rbd_obj_header_ondisk *)bl.c_str();
+
+  int snaps_id_ofs = sizeof(*header);
+  int names_ofs = snaps_id_ofs + sizeof(*new_snaps) * header->snap_count;
+  const char *snap_name;
+  const char *snap_names = ((char *)header) + names_ofs;
+  const char *end = snap_names + header->snap_names_len;
+  auto iter = in->cbegin();
+  string s;
+  uint64_t snap_id;
+
+  try {
+    decode(s, iter);
+    decode(snap_id, iter);
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+  snap_name = s.c_str();
+
+  if (header->snap_seq > snap_id)
+    return -ESTALE;
+
+  uint64_t snap_limit;
+  rc = read_key(hctx, "snap_limit", &snap_limit);
+  if (rc == -ENOENT) {
+    snap_limit = UINT64_MAX;
+  } else if (rc < 0) {
+    return rc;
+  }
+
+  if (header->snap_count >= snap_limit)
+    return -EDQUOT;
+
+  const char *cur_snap_name;
+  for (cur_snap_name = snap_names; cur_snap_name < end; cur_snap_name += strlen(cur_snap_name) + 1) {
+    if (strncmp(cur_snap_name, snap_name, end - cur_snap_name) == 0)
+      return -EEXIST;
+  }
+  if (cur_snap_name > end)
+    return -EIO;
+
+  int snap_name_len = strlen(snap_name);
+
+  bufferptr new_names_bp(header->snap_names_len + snap_name_len + 1);
+  bufferptr new_snaps_bp(sizeof(*new_snaps) * (header->snap_count + 1));
+
+  /* copy snap names and append to new snap name */
+  char *new_snap_names = new_names_bp.c_str();
+  strcpy(new_snap_names, snap_name);
+  memcpy(new_snap_names + snap_name_len + 1, snap_names, header->snap_names_len);
+
+  /* append new snap id */
+  new_snaps = (struct rbd_obj_snap_ondisk *)new_snaps_bp.c_str();
+  memcpy(new_snaps + 1, header->snaps, sizeof(*new_snaps) * header->snap_count);
+
+  header->snap_count = header->snap_count + 1;
+  header->snap_names_len = header->snap_names_len + snap_name_len + 1;
+  header->snap_seq = snap_id;
+
+  new_snaps[0].id = snap_id;
+  new_snaps[0].image_size = header->image_size;
+
+  memcpy(header_bp.c_str(), header, sizeof(*header));
+
+  newbl.push_back(header_bp);
+  newbl.push_back(new_snaps_bp);
+  newbl.push_back(new_names_bp);
+
+  rc = cls_cxx_write_full(hctx, &newbl);
+  if (rc < 0)
+    return rc;
+
+  return 0;
+}
+
+int old_snapshot_remove(cls_method_context_t hctx, bufferlist *in, bufferlist *out)
+{
+  bufferlist bl;
+  struct rbd_obj_header_ondisk *header;
+  bufferlist newbl;
+  bufferptr header_bp(sizeof(*header));
+
+  int rc = snap_read_header(hctx, bl);
+  if (rc < 0)
+    return rc;
+
+  header = (struct rbd_obj_header_ondisk *)bl.c_str();
+
+  int snaps_id_ofs = sizeof(*header);
+  int names_ofs = snaps_id_ofs + sizeof(struct rbd_obj_snap_ondisk) * header->snap_count;
+  const char *snap_name;
+  const char *snap_names = ((char *)header) + names_ofs;
+  const char *orig_names = snap_names;
+  const char *end = snap_names + header->snap_names_len;
+  auto iter = in->cbegin();
+  string s;
+  unsigned i;
+  bool found = false;
+  struct rbd_obj_snap_ondisk snap;
+
+  try {
+    decode(s, iter);
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+  snap_name = s.c_str();
+
+  for (i = 0; snap_names < end; i++) {
+    if (strcmp(snap_names, snap_name) == 0) {
+      snap = header->snaps[i];
+      found = true;
+      break;
+    }
+    snap_names += strlen(snap_names) + 1;
+  }
+  if (!found) {
+    CLS_ERR("couldn't find snap %s\n", snap_name);
+    return -ENOENT;
+  }
+
+  header->snap_names_len  = header->snap_names_len - (s.length() + 1);
+  header->snap_count = header->snap_count - 1;
+
+  bufferptr new_names_bp(header->snap_names_len);
+  bufferptr new_snaps_bp(sizeof(header->snaps[0]) * header->snap_count);
+
+  memcpy(header_bp.c_str(), header, sizeof(*header));
+  newbl.push_back(header_bp);
+
+  if (header->snap_count) {
+    int snaps_len = 0;
+    int names_len = 0;
+    CLS_LOG(20, "i=%u\n", i);
+    if (i > 0) {
+      snaps_len = sizeof(header->snaps[0]) * i;
+      names_len =  snap_names - orig_names;
+      memcpy(new_snaps_bp.c_str(), header->snaps, snaps_len);
+      memcpy(new_names_bp.c_str(), orig_names, names_len);
+    }
+    snap_names += s.length() + 1;
+
+    if (i < header->snap_count) {
+      memcpy(new_snaps_bp.c_str() + snaps_len,
+             header->snaps + i + 1,
+             sizeof(header->snaps[0]) * (header->snap_count - i));
+      memcpy(new_names_bp.c_str() + names_len, snap_names , end - snap_names);
+    }
+    newbl.push_back(new_snaps_bp);
+    newbl.push_back(new_names_bp);
+  }
+
+  rc = cls_cxx_write_full(hctx, &newbl);
+  if (rc < 0)
+    return rc;
+
+  return 0;
+}
+
+/**
+ * rename snapshot of old format.
+ *
+ * Input:
+ * @param src_snap_id old snap id of the snapshot (snapid_t)
+ * @param dst_snap_name new name of the snapshot (string)
+ *
+ * Output:
+ * @returns 0 on success, negative error code on failure.
+*/
+int old_snapshot_rename(cls_method_context_t hctx, bufferlist *in, bufferlist *out)
+{
+  bufferlist bl;
+  struct rbd_obj_header_ondisk *header;
+  bufferlist newbl;
+  bufferptr header_bp(sizeof(*header));
+  snapid_t src_snap_id;
+  const char *dst_snap_name;
+  string dst;
+
+  int rc = snap_read_header(hctx, bl);
+  if (rc < 0)
+    return rc;
+
+  header = (struct rbd_obj_header_ondisk *)bl.c_str();
+
+  int snaps_id_ofs = sizeof(*header);
+  int names_ofs = snaps_id_ofs + sizeof(rbd_obj_snap_ondisk) * header->snap_count;
+  const char *snap_names = ((char *)header) + names_ofs;
+  const char *orig_names = snap_names;
+  const char *end = snap_names + header->snap_names_len;
+  auto iter = in->cbegin();
+  unsigned i;
+  bool found = false;
+
+  try {
+    decode(src_snap_id, iter);
+    decode(dst, iter);
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+  dst_snap_name = dst.c_str();
+
+  const char *cur_snap_name;
+  for (cur_snap_name = snap_names; cur_snap_name < end; 
+    cur_snap_name += strlen(cur_snap_name) + 1) {
+    if (strcmp(cur_snap_name, dst_snap_name) == 0)
+      return -EEXIST;
+  }
+  if (cur_snap_name > end)
+    return -EIO;
+  for (i = 0; i < header->snap_count; i++) {
+    if (src_snap_id == header->snaps[i].id) {
+      found = true;
+      break;
+    }
+    snap_names += strlen(snap_names) + 1;
+  }
+  if (!found) {
+    CLS_ERR("couldn't find snap %llu\n", (unsigned long long)src_snap_id.val);
+    return -ENOENT;
+  }
+  
+  CLS_LOG(20, "rename snap with snap id %llu to dest name %s", (unsigned long long)src_snap_id.val, dst_snap_name);
+  header->snap_names_len  = header->snap_names_len - strlen(snap_names) + dst.length();
+
+  bufferptr new_names_bp(header->snap_names_len);
+  bufferptr new_snaps_bp(sizeof(header->snaps[0]) * header->snap_count);
+
+  if (header->snap_count) {
+    int names_len = 0;
+    CLS_LOG(20, "i=%u\n", i);
+    if (i > 0) {
+      names_len =  snap_names - orig_names;
+      memcpy(new_names_bp.c_str(), orig_names, names_len);
+    }
+    strcpy(new_names_bp.c_str() + names_len, dst_snap_name);
+    names_len += strlen(dst_snap_name) + 1;
+    snap_names += strlen(snap_names) + 1;
+    if (i < header->snap_count) {
+      memcpy(new_names_bp.c_str() + names_len, snap_names , end - snap_names);
+    }
+    memcpy(new_snaps_bp.c_str(), header->snaps, sizeof(header->snaps[0]) * header->snap_count);
+  }
+
+  memcpy(header_bp.c_str(), header, sizeof(*header));
+  newbl.push_back(header_bp);
+  newbl.push_back(new_snaps_bp);
+  newbl.push_back(new_names_bp);
+
+  rc = cls_cxx_write_full(hctx, &newbl);
+  if (rc < 0)
+    return rc;
+  return 0;
+}
+
+
+namespace mirror {
+
+static const std::string UUID("mirror_uuid");
+static const std::string MODE("mirror_mode");
+static const std::string PEER_KEY_PREFIX("mirror_peer_");
+static const std::string IMAGE_KEY_PREFIX("image_");
+static const std::string GLOBAL_KEY_PREFIX("global_");
+static const std::string STATUS_GLOBAL_KEY_PREFIX("status_global_");
+static const std::string REMOTE_STATUS_GLOBAL_KEY_PREFIX("remote_status_global_");
+static const std::string INSTANCE_KEY_PREFIX("instance_");
+static const std::string MIRROR_IMAGE_MAP_KEY_PREFIX("image_map_");
+
+std::string peer_key(const std::string &uuid) {
+  return PEER_KEY_PREFIX + uuid;
+}
+
+std::string image_key(const string &image_id) {
+  return IMAGE_KEY_PREFIX + image_id;
+}
+
+std::string global_key(const string &global_id) {
+  return GLOBAL_KEY_PREFIX + global_id;
+}
+
+std::string remote_status_global_key(const std::string& global_id,
+                                     const std::string& mirror_uuid) {
+  return REMOTE_STATUS_GLOBAL_KEY_PREFIX + global_id + "_" + mirror_uuid;
+}
+
+std::string status_global_key(const std::string& global_id,
+                              const std::string& mirror_uuid) {
+  if (mirror_uuid == cls::rbd::MirrorImageSiteStatus::LOCAL_MIRROR_UUID) {
+    return STATUS_GLOBAL_KEY_PREFIX + global_id;
+  } else {
+    return remote_status_global_key(global_id, mirror_uuid);
+  }
+}
+
+std::string instance_key(const string &instance_id) {
+  return INSTANCE_KEY_PREFIX + instance_id;
+}
+
+std::string mirror_image_map_key(const string& global_image_id) {
+  return MIRROR_IMAGE_MAP_KEY_PREFIX + global_image_id;
+}
+
+int uuid_get(cls_method_context_t hctx, std::string *mirror_uuid) {
+  bufferlist mirror_uuid_bl;
+  int r = cls_cxx_map_get_val(hctx, mirror::UUID, &mirror_uuid_bl);
+  if (r < 0) {
+    if (r != -ENOENT) {
+      CLS_ERR("error reading mirror uuid: %s", cpp_strerror(r).c_str());
+    }
+    return r;
+  }
+
+  *mirror_uuid = std::string(mirror_uuid_bl.c_str(), mirror_uuid_bl.length());
+  return 0;
+}
+
+int list_watchers(cls_method_context_t hctx,
+                  std::set<entity_inst_t> *entities) {
+  obj_list_watch_response_t watchers;
+  int r = cls_cxx_list_watchers(hctx, &watchers);
+  if (r < 0 && r != -ENOENT) {
+    CLS_ERR("error listing watchers: '%s'", cpp_strerror(r).c_str());
+    return r;
+  }
+
+  entities->clear();
+  for (auto &w : watchers.entries) {
+    entity_inst_t entity_inst{w.name, w.addr};
+    cls::rbd::sanitize_entity_inst(&entity_inst);
+
+    entities->insert(entity_inst);
+  }
+  return 0;
+}
+
+int read_peers(cls_method_context_t hctx,
+               std::vector<cls::rbd::MirrorPeer> *peers) {
+  std::string last_read = PEER_KEY_PREFIX;
+  int max_read = RBD_MAX_KEYS_READ;
+  bool more = true;
+  while (more) {
+    std::map<std::string, bufferlist> vals;
+    int r = cls_cxx_map_get_vals(hctx, last_read, PEER_KEY_PREFIX.c_str(),
+                                 max_read, &vals, &more);
+    if (r < 0) {
+      if (r != -ENOENT) {
+        CLS_ERR("error reading peers: %s", cpp_strerror(r).c_str());
+      }
+      return r;
+    }
+
+    for (auto &it : vals) {
+      try {
+        auto bl_it = it.second.cbegin();
+        cls::rbd::MirrorPeer peer;
+	decode(peer, bl_it);
+        peers->push_back(peer);
+      } catch (const ceph::buffer::error &err) {
+	CLS_ERR("could not decode peer '%s'", it.first.c_str());
+	return -EIO;
+      }
+    }
+
+    if (!vals.empty()) {
+      last_read = vals.rbegin()->first;
+    }
+  }
+  return 0;
+}
+
+int read_peer(cls_method_context_t hctx, const std::string &id,
+              cls::rbd::MirrorPeer *peer) {
+  bufferlist bl;
+  int r = cls_cxx_map_get_val(hctx, peer_key(id), &bl);
+  if (r < 0) {
+    CLS_ERR("error reading peer '%s': %s", id.c_str(),
+            cpp_strerror(r).c_str());
+    return r;
+  }
+
+  try {
+    auto bl_it = bl.cbegin();
+    decode(*peer, bl_it);
+  } catch (const ceph::buffer::error &err) {
+    CLS_ERR("could not decode peer '%s'", id.c_str());
+    return -EIO;
+  }
+  return 0;
+}
+
+int write_peer(cls_method_context_t hctx, const cls::rbd::MirrorPeer &peer) {
+  bufferlist bl;
+  encode(peer, bl);
+
+  int r = cls_cxx_map_set_val(hctx, peer_key(peer.uuid), &bl);
+  if (r < 0) {
+    CLS_ERR("error writing peer '%s': %s", peer.uuid.c_str(),
+            cpp_strerror(r).c_str());
+    return r;
+  }
+  return 0;
+}
+
+int check_mirroring_enabled(cls_method_context_t hctx) {
+  uint32_t mirror_mode_decode;
+  int r = read_key(hctx, mirror::MODE, &mirror_mode_decode);
+  if (r < 0 && r != -ENOENT) {
+    return r;
+  } else if (r == -ENOENT ||
+             mirror_mode_decode == cls::rbd::MIRROR_MODE_DISABLED) {
+    CLS_ERR("mirroring must be enabled on the pool");
+    return -EINVAL;
+  }
+
+  return 0;
+}
+
+int peer_ping(cls_method_context_t hctx, const std::string& site_name,
+              const std::string& mirror_uuid) {
+  int r = check_mirroring_enabled(hctx);
+  if (r < 0) {
+    return r;
+  }
+
+  if (site_name.empty() || mirror_uuid.empty()) {
+    return -EINVAL;
+  }
+
+  std::vector<cls::rbd::MirrorPeer> peers;
+  r = read_peers(hctx, &peers);
+  if (r < 0 && r != -ENOENT) {
+    return r;
+  }
+
+
+  cls::rbd::MirrorPeer mirror_peer;
+  auto site_it = std::find_if(peers.begin(), peers.end(),
+                              [&site_name](auto& peer) {
+      return (peer.site_name == site_name);
+    });
+
+  auto mirror_uuid_it = peers.end();
+  if (site_it == peers.end() ||
+      (!site_it->mirror_uuid.empty() && site_it->mirror_uuid != mirror_uuid)) {
+    // search for existing peer w/ same mirror_uuid
+    mirror_uuid_it = std::find_if(peers.begin(), peers.end(),
+                                  [&mirror_uuid](auto& peer) {
+        return (peer.mirror_uuid == mirror_uuid);
+      });
+  }
+
+  auto it = peers.end();
+  if (site_it != peers.end() && mirror_uuid_it != peers.end()) {
+    // implies two peers -- match by mirror_uuid but don't update site name
+    it = mirror_uuid_it;
+  } else if (mirror_uuid_it != peers.end()) {
+    // implies site name has been updated in remote
+    mirror_uuid_it->site_name = site_name;
+    it = mirror_uuid_it;
+  } else if (site_it != peers.end()) {
+    // implies empty mirror_uuid in peer
+    site_it->mirror_uuid = mirror_uuid;
+    it = site_it;
+  } else {
+    CLS_LOG(10, "auto-generating new TX-only peer: %s", site_name.c_str());
+
+    uuid_d uuid_gen;
+    while (true) {
+      uuid_gen.generate_random();
+      mirror_peer.uuid = uuid_gen.to_string();
+
+      bufferlist bl;
+      r = cls_cxx_map_get_val(hctx, peer_key(mirror_peer.uuid), &bl);
+      if (r == -ENOENT) {
+        break;
+      } else if (r < 0) {
+        CLS_ERR("failed to retrieve mirror peer: %s", cpp_strerror(r).c_str());
+        return r;
+      }
+    }
+
+    mirror_peer.mirror_peer_direction = cls::rbd::MIRROR_PEER_DIRECTION_TX;
+    mirror_peer.site_name = site_name;
+    mirror_peer.mirror_uuid = mirror_uuid;
+  }
+
+  if (it != peers.end()) {
+    mirror_peer = *it;
+
+    if (mirror_peer.mirror_peer_direction ==
+          cls::rbd::MIRROR_PEER_DIRECTION_RX) {
+      CLS_LOG(10, "switching to RX/TX peer: %s", site_name.c_str());
+      mirror_peer.mirror_peer_direction = cls::rbd::MIRROR_PEER_DIRECTION_RX_TX;
+    }
+  }
+
+  mirror_peer.last_seen = ceph_clock_now();
+
+  if (!mirror_peer.is_valid()) {
+    CLS_ERR("attempting to update invalid peer: %s", site_name.c_str());
+    return -EINVAL;
+  }
+
+  r = write_peer(hctx, mirror_peer);
+  if (r < 0) {
+    return r;
+  }
+
+  return 0;
+}
+
+int peer_add(cls_method_context_t hctx, cls::rbd::MirrorPeer mirror_peer) {
+  int r = check_mirroring_enabled(hctx);
+  if (r < 0) {
+    return r;
+  }
+
+  if (!mirror_peer.is_valid()) {
+    CLS_ERR("mirror peer is not valid");
+    return -EINVAL;
+  }
+
+  std::string mirror_uuid;
+  r = uuid_get(hctx, &mirror_uuid);
+  if (r < 0) {
+    CLS_ERR("error retrieving mirroring uuid: %s", cpp_strerror(r).c_str());
+    return r;
+  } else if (mirror_peer.uuid == mirror_uuid) {
+    CLS_ERR("peer uuid '%s' matches pool mirroring uuid",
+            mirror_uuid.c_str());
+    return -EINVAL;
+  } else if (mirror_peer.mirror_peer_direction ==
+               cls::rbd::MIRROR_PEER_DIRECTION_TX) {
+    CLS_ERR("peer uuid '%s' cannot use TX-only direction",
+            mirror_peer.uuid.c_str());
+    return -EINVAL;
+  }
+
+  std::vector<cls::rbd::MirrorPeer> peers;
+  r = read_peers(hctx, &peers);
+  if (r < 0 && r != -ENOENT) {
+    return r;
+  }
+
+  for (auto const &peer : peers) {
+    if (peer.uuid == mirror_peer.uuid) {
+      CLS_ERR("peer uuid '%s' already exists",
+              peer.uuid.c_str());
+      return -ESTALE;
+    } else if (peer.site_name == mirror_peer.site_name) {
+      CLS_ERR("peer site name '%s' already exists",
+              peer.site_name.c_str());
+      return -EEXIST;
+    } else if (!mirror_peer.mirror_uuid.empty() &&
+               peer.mirror_uuid == mirror_peer.mirror_uuid) {
+      CLS_ERR("peer mirror uuid '%s' already exists",
+              peer.mirror_uuid.c_str());
+      return -EEXIST;
+    }
+  }
+
+  r = write_peer(hctx, mirror_peer);
+  if (r < 0) {
+    return r;
+  }
+  return 0;
+}
+
+int peer_remove(cls_method_context_t hctx, const std::string& uuid) {
+  int r = cls_cxx_map_remove_key(hctx, peer_key(uuid));
+  if (r < 0 && r != -ENOENT) {
+    CLS_ERR("error removing peer: %s", cpp_strerror(r).c_str());
+    return r;
+  }
+  return 0;
+}
+
+int image_get(cls_method_context_t hctx, const string &image_id,
+	      cls::rbd::MirrorImage *mirror_image) {
+  bufferlist bl;
+  int r = cls_cxx_map_get_val(hctx, image_key(image_id), &bl);
+  if (r < 0) {
+    if (r != -ENOENT) {
+      CLS_ERR("error reading mirrored image '%s': '%s'", image_id.c_str(),
+	      cpp_strerror(r).c_str());
+    }
+    return r;
+  }
+
+  try {
+    auto it = bl.cbegin();
+    decode(*mirror_image, it);
+  } catch (const ceph::buffer::error &err) {
+    CLS_ERR("could not decode mirrored image '%s'", image_id.c_str());
+    return -EIO;
+  }
+
+  return 0;
+}
+
+int image_set(cls_method_context_t hctx, const string &image_id,
+	      const cls::rbd::MirrorImage &mirror_image) {
+  bufferlist bl;
+  encode(mirror_image, bl);
+
+  cls::rbd::MirrorImage existing_mirror_image;
+  int r = image_get(hctx, image_id, &existing_mirror_image);
+  if (r == -ENOENT) {
+    // make sure global id doesn't already exist
+    std::string global_id_key = global_key(mirror_image.global_image_id);
+    std::string image_id;
+    r = read_key(hctx, global_id_key, &image_id);
+    if (r >= 0) {
+      return -EEXIST;
+    } else if (r != -ENOENT) {
+      CLS_ERR("error reading global image id: '%s': '%s'", image_id.c_str(),
+              cpp_strerror(r).c_str());
+      return r;
+    }
+
+    // make sure this was not a race for disabling
+    if (mirror_image.state == cls::rbd::MIRROR_IMAGE_STATE_DISABLING) {
+      CLS_ERR("image '%s' is already disabled", image_id.c_str());
+      return r;
+    }
+  } else if (r < 0) {
+    CLS_ERR("error reading mirrored image '%s': '%s'", image_id.c_str(),
+	    cpp_strerror(r).c_str());
+    return r;
+  } else if (existing_mirror_image.global_image_id !=
+                mirror_image.global_image_id) {
+    // cannot change the global id
+    return -EINVAL;
+  }
+
+  r = cls_cxx_map_set_val(hctx, image_key(image_id), &bl);
+  if (r < 0) {
+    CLS_ERR("error adding mirrored image '%s': %s", image_id.c_str(),
+            cpp_strerror(r).c_str());
+    return r;
+  }
+
+  bufferlist image_id_bl;
+  encode(image_id, image_id_bl);
+  r = cls_cxx_map_set_val(hctx, global_key(mirror_image.global_image_id),
+                          &image_id_bl);
+  if (r < 0) {
+    CLS_ERR("error adding global id for image '%s': %s", image_id.c_str(),
+            cpp_strerror(r).c_str());
+    return r;
+  }
+  return 0;
+}
+
+int image_status_remove(cls_method_context_t hctx,
+			const string &global_image_id);
+
+int image_remove(cls_method_context_t hctx, const string &image_id) {
+  bufferlist bl;
+  cls::rbd::MirrorImage mirror_image;
+  int r = image_get(hctx, image_id, &mirror_image);
+  if (r < 0) {
+    if (r != -ENOENT) {
+      CLS_ERR("error reading mirrored image '%s': '%s'", image_id.c_str(),
+	      cpp_strerror(r).c_str());
+    }
+    return r;
+  }
+
+  if (mirror_image.state != cls::rbd::MIRROR_IMAGE_STATE_DISABLING) {
+    return -EBUSY;
+  }
+
+  r = cls_cxx_map_remove_key(hctx, image_key(image_id));
+  if (r < 0) {
+    CLS_ERR("error removing mirrored image '%s': %s", image_id.c_str(),
+            cpp_strerror(r).c_str());
+    return r;
+  }
+
+  r = cls_cxx_map_remove_key(hctx, global_key(mirror_image.global_image_id));
+  if (r < 0 && r != -ENOENT) {
+    CLS_ERR("error removing global id for image '%s': %s", image_id.c_str(),
+           cpp_strerror(r).c_str());
+    return r;
+  }
+
+  r = image_status_remove(hctx, mirror_image.global_image_id);
+  if (r < 0) {
+    return r;
+  }
+
+  return 0;
+}
+
+int image_status_set(cls_method_context_t hctx, const string &global_image_id,
+		     const cls::rbd::MirrorImageSiteStatus &status) {
+  cls::rbd::MirrorImageSiteStatusOnDisk ondisk_status(status);
+  ondisk_status.mirror_uuid = ""; // mirror_uuid stored in key
+  ondisk_status.up = false;
+  ondisk_status.last_update = ceph_clock_now();
+
+  std::string global_id_key = global_key(global_image_id);
+  std::string image_id;
+  int r = read_key(hctx, global_id_key, &image_id);
+  if (r < 0) {
+    return 0;
+  }
+  cls::rbd::MirrorImage mirror_image;
+  r = image_get(hctx, image_id, &mirror_image);
+  if (r < 0) {
+    return 0;
+  }
+  if (mirror_image.state != cls::rbd::MIRROR_IMAGE_STATE_ENABLED) {
+    return 0;
+  }
+
+  r = cls_get_request_origin(hctx, &ondisk_status.origin);
+  ceph_assert(r == 0);
+
+  bufferlist bl;
+  encode(ondisk_status, bl, cls_get_features(hctx));
+
+  r = cls_cxx_map_set_val(hctx, status_global_key(global_image_id,
+                                                  status.mirror_uuid), &bl);
+  if (r < 0) {
+    CLS_ERR("error setting status for mirrored image, global id '%s', "
+            "site '%s': %s", global_image_id.c_str(),
+            status.mirror_uuid.c_str(),
+            cpp_strerror(r).c_str());
+    return r;
+  }
+  return 0;
+}
+
+int get_remote_image_status_mirror_uuids(cls_method_context_t hctx,
+                                         const std::string& global_image_id,
+                                         std::set<std::string>* mirror_uuids) {
+  std::string filter = remote_status_global_key(global_image_id, "");
+  std::string last_read = filter;
+  int max_read = 4; // we don't expect lots of peers
+  bool more = true;
+
+  do {
+    std::set<std::string> keys;
+    int r = cls_cxx_map_get_keys(hctx, last_read, max_read, &keys, &more);
+    if (r < 0) {
+      return r;
+    }
+
+    for (auto& key : keys) {
+      if (!boost::starts_with(key, filter)) {
+        more = false;
+        break;
+      }
+
+      mirror_uuids->insert(key.substr(filter.length()));
+    }
+
+    if (!keys.empty()) {
+      last_read = *keys.rbegin();
+    }
+  } while (more);
+
+  return 0;
+}
+
+int image_status_remove(cls_method_context_t hctx,
+			const string &global_image_id) {
+  // remove all local/remote image statuses
+  std::set<std::string> mirror_uuids;
+  int r = get_remote_image_status_mirror_uuids(hctx, global_image_id,
+                                               &mirror_uuids);
+  if (r < 0 && r != -ENOENT) {
+    return r;
+  }
+
+  mirror_uuids.insert(cls::rbd::MirrorImageSiteStatus::LOCAL_MIRROR_UUID);
+  for (auto& mirror_uuid : mirror_uuids) {
+    CLS_LOG(20, "removing status object for mirror_uuid %s",
+            mirror_uuid.c_str());
+    auto key = status_global_key(global_image_id, mirror_uuid);
+    r = cls_cxx_map_remove_key(hctx, key);
+    if (r < 0 && r != -ENOENT) {
+      CLS_ERR("error removing stale status for key '%s': %s",
+              key.c_str(), cpp_strerror(r).c_str());
+      return r;
+    }
+  }
+
+  return 0;
+}
+
+int image_status_get(cls_method_context_t hctx, const string &global_image_id,
+                     const std::string& mirror_uuid, const bufferlist& bl,
+                     const std::set<entity_inst_t> &watchers,
+                     cls::rbd::MirrorImageStatus* status) {
+  cls::rbd::MirrorImageSiteStatusOnDisk ondisk_status;
+  try {
+    auto it = bl.cbegin();
+    decode(ondisk_status, it);
+  } catch (const ceph::buffer::error &err) {
+    CLS_ERR("could not decode status for mirrored image, global id '%s', "
+            "site '%s'",
+            global_image_id.c_str(), mirror_uuid.c_str());
+    return -EIO;
+  }
+
+  auto site_status = static_cast<cls::rbd::MirrorImageSiteStatus>(
+    ondisk_status);
+  site_status.up = (watchers.find(ondisk_status.origin) != watchers.end());
+  site_status.mirror_uuid = mirror_uuid;
+  status->mirror_image_site_statuses.push_back(site_status);
+  return 0;
+}
+
+int image_status_get_local(cls_method_context_t hctx,
+                           const string &global_image_id,
+                           const std::set<entity_inst_t> &watchers,
+                           cls::rbd::MirrorImageStatus *status) {
+  bufferlist bl;
+  int r = cls_cxx_map_get_val(
+    hctx, status_global_key(global_image_id,
+                            cls::rbd::MirrorImageSiteStatus::LOCAL_MIRROR_UUID),
+                            &bl);
+  if (r == -ENOENT) {
+    return 0;
+  } else if (r < 0) {
+    CLS_ERR("error reading status for mirrored image, global id '%s', "
+            "site '%s': '%s'",
+            global_image_id.c_str(),
+            cls::rbd::MirrorImageSiteStatus::LOCAL_MIRROR_UUID.c_str(),
+            cpp_strerror(r).c_str());
+    return r;
+  }
+
+  return image_status_get(hctx, global_image_id,
+                          cls::rbd::MirrorImageSiteStatus::LOCAL_MIRROR_UUID,
+                          bl, watchers, status);
+}
+
+int image_status_get_remote(cls_method_context_t hctx,
+                            const string &global_image_id,
+                            const std::set<entity_inst_t> &watchers,
+                            cls::rbd::MirrorImageStatus *status) {
+  std::string filter = remote_status_global_key(global_image_id, "");
+  std::string last_read = filter;
+  int max_read = RBD_MAX_KEYS_READ;
+  bool more = true;
+
+  do {
+    std::map<std::string, bufferlist> vals;
+    CLS_LOG(20, "last_read = '%s'", last_read.c_str());
+    int r = cls_cxx_map_get_vals(hctx, last_read, filter, max_read, &vals,
+                                 &more);
+    if (r == -ENOENT) {
+      return 0;
+    } else if (r < 0) {
+      return r;
+    }
+
+    for (auto& it : vals) {
+      auto mirror_uuid = it.first.substr(filter.length());
+      CLS_LOG(20, "mirror_uuid = '%s'", mirror_uuid.c_str());
+      r = image_status_get(hctx, global_image_id, mirror_uuid, it.second,
+                           watchers, status);
+      if (r < 0) {
+        return r;
+      }
+    }
+
+    if (!vals.empty()) {
+      last_read = vals.rbegin()->first;
+    }
+  } while (more);
+
+  return 0;
+}
+
+int image_status_get(cls_method_context_t hctx, const string &global_image_id,
+                     const std::set<entity_inst_t> &watchers,
+                     cls::rbd::MirrorImageStatus *status) {
+  status->mirror_image_site_statuses.clear();
+
+  // collect local site status
+  int r = image_status_get_local(hctx, global_image_id, watchers, status);
+  if (r < 0) {
+    return r;
+  }
+
+  // collect remote site status (TX to peer)
+  r = image_status_get_remote(hctx, global_image_id, watchers, status);
+  if (r < 0) {
+    return r;
+  }
+
+  if (status->mirror_image_site_statuses.empty()) {
+    return -ENOENT;
+  }
+
+  return 0;
+}
+
+int image_status_list(cls_method_context_t hctx,
+	const std::string &start_after, uint64_t max_return,
+	map<std::string, cls::rbd::MirrorImage> *mirror_images,
+        map<std::string, cls::rbd::MirrorImageStatus> *mirror_statuses) {
+  std::string last_read = image_key(start_after);
+  int max_read = RBD_MAX_KEYS_READ;
+  bool more = true;
+
+  std::set<entity_inst_t> watchers;
+  int r = list_watchers(hctx, &watchers);
+  if (r < 0) {
+    return r;
+  }
+
+  while (more && mirror_images->size() < max_return) {
+    std::map<std::string, bufferlist> vals;
+    CLS_LOG(20, "last_read = '%s'", last_read.c_str());
+    r = cls_cxx_map_get_vals(hctx, last_read, IMAGE_KEY_PREFIX, max_read, &vals,
+                             &more);
+    if (r < 0) {
+      if (r != -ENOENT) {
+        CLS_ERR("error reading mirror image directory by name: %s",
+                cpp_strerror(r).c_str());
+      }
+      return r;
+    }
+
+    for (auto it = vals.begin(); it != vals.end() &&
+	   mirror_images->size() < max_return; ++it) {
+      const std::string &image_id = it->first.substr(IMAGE_KEY_PREFIX.size());
+      cls::rbd::MirrorImage mirror_image;
+      auto iter = it->second.cbegin();
+      try {
+	decode(mirror_image, iter);
+      } catch (const ceph::buffer::error &err) {
+	CLS_ERR("could not decode mirror image payload of image '%s'",
+                image_id.c_str());
+	return -EIO;
+      }
+
+      (*mirror_images)[image_id] = mirror_image;
+
+      cls::rbd::MirrorImageStatus status;
+      int r1 = image_status_get(hctx, mirror_image.global_image_id, watchers,
+                                &status);
+      if (r1 < 0) {
+	continue;
+      }
+
+      (*mirror_statuses)[image_id] = status;
+    }
+    if (!vals.empty()) {
+      last_read = image_key(mirror_images->rbegin()->first);
+    }
+  }
+
+  return 0;
+}
+
+cls::rbd::MirrorImageStatusState compute_image_status_summary_state(
+    cls::rbd::MirrorPeerDirection mirror_peer_direction,
+    const std::set<std::string>& tx_peer_mirror_uuids,
+    const cls::rbd::MirrorImageStatus& status) {
+  std::optional<cls::rbd::MirrorImageStatusState> state = {};
+
+  cls::rbd::MirrorImageSiteStatus local_status;
+  status.get_local_mirror_image_site_status(&local_status);
+
+  uint64_t unmatched_tx_peers = 0;
+  switch (mirror_peer_direction) {
+  case cls::rbd::MIRROR_PEER_DIRECTION_RX:
+    // if we are RX-only, summary is based on our local status
+    if (local_status.up) {
+      state = local_status.state;
+    }
+    break;
+  case cls::rbd::MIRROR_PEER_DIRECTION_RX_TX:
+    // if we are RX/TX, combine all statuses
+    if (local_status.up) {
+      state = local_status.state;
+    }
+    [[fallthrough]];
+  case cls::rbd::MIRROR_PEER_DIRECTION_TX:
+    // if we are TX-only, summary is based on remote status
+    unmatched_tx_peers = tx_peer_mirror_uuids.size();
+    for (auto& remote_status : status.mirror_image_site_statuses) {
+      if (remote_status.mirror_uuid ==
+            cls::rbd::MirrorImageSiteStatus::LOCAL_MIRROR_UUID) {
+        continue;
+      }
+
+      if (unmatched_tx_peers > 0 &&
+          tx_peer_mirror_uuids.count(remote_status.mirror_uuid) > 0) {
+        --unmatched_tx_peers;
+      }
+
+      auto remote_state = (remote_status.up ?
+        remote_status.state : cls::rbd::MIRROR_IMAGE_STATUS_STATE_UNKNOWN);
+      if (remote_status.state == cls::rbd::MIRROR_IMAGE_STATUS_STATE_ERROR) {
+        state = remote_status.state;
+      } else if (!state) {
+        state = remote_state;
+      } else if (*state != cls::rbd::MIRROR_IMAGE_STATUS_STATE_ERROR) {
+        state = std::min(*state, remote_state);
+      }
+    }
+    break;
+  default:
+    break;
+  }
+
+  if (!state || unmatched_tx_peers > 0) {
+    state = cls::rbd::MIRROR_IMAGE_STATUS_STATE_UNKNOWN;
+  }
+  return *state;
+}
+
+int image_status_get_summary(
+    cls_method_context_t hctx,
+    cls::rbd::MirrorPeerDirection mirror_peer_direction,
+    const std::set<std::string>& tx_peer_mirror_uuids,
+    std::map<cls::rbd::MirrorImageStatusState, int32_t> *states) {
+  std::set<entity_inst_t> watchers;
+  int r = list_watchers(hctx, &watchers);
+  if (r < 0) {
+    return r;
+  }
+
+  states->clear();
+
+  string last_read = IMAGE_KEY_PREFIX;
+  int max_read = RBD_MAX_KEYS_READ;
+  bool more = true;
+  while (more) {
+    map<string, bufferlist> vals;
+    r = cls_cxx_map_get_vals(hctx, last_read, IMAGE_KEY_PREFIX,
+			     max_read, &vals, &more);
+    if (r < 0) {
+      if (r != -ENOENT) {
+        CLS_ERR("error reading mirrored images: %s", cpp_strerror(r).c_str());
+      }
+      return r;
+    }
+
+    for (auto &list_it : vals) {
+      const string &key = list_it.first;
+
+      if (0 != key.compare(0, IMAGE_KEY_PREFIX.size(), IMAGE_KEY_PREFIX)) {
+	break;
+      }
+
+      cls::rbd::MirrorImage mirror_image;
+      auto iter = list_it.second.cbegin();
+      try {
+	decode(mirror_image, iter);
+      } catch (const ceph::buffer::error &err) {
+	CLS_ERR("could not decode mirror image payload for key '%s'",
+                key.c_str());
+	return -EIO;
+      }
+
+      cls::rbd::MirrorImageStatus status;
+      r = image_status_get(hctx, mirror_image.global_image_id, watchers,
+                           &status);
+      if (r < 0 && r != -ENOENT) {
+        return r;
+      }
+
+      auto state = compute_image_status_summary_state(
+        mirror_peer_direction, tx_peer_mirror_uuids, status);
+      (*states)[state]++;
+    }
+
+    if (!vals.empty()) {
+      last_read = vals.rbegin()->first;
+    }
+  }
+
+  return 0;
+}
+
+int image_status_remove_down(cls_method_context_t hctx) {
+  std::set<entity_inst_t> watchers;
+  int r = list_watchers(hctx, &watchers);
+  if (r < 0) {
+    return r;
+  }
+
+  std::vector<std::string> prefixes = {
+    STATUS_GLOBAL_KEY_PREFIX, REMOTE_STATUS_GLOBAL_KEY_PREFIX};
+  for (auto& prefix : prefixes) {
+    std::string last_read = prefix;
+    int max_read = RBD_MAX_KEYS_READ;
+    bool more = true;
+    while (more) {
+      std::map<std::string, bufferlist> vals;
+      r = cls_cxx_map_get_vals(hctx, last_read, prefix, max_read, &vals, &more);
+      if (r < 0) {
+        if (r != -ENOENT) {
+          CLS_ERR("error reading mirrored images: %s", cpp_strerror(r).c_str());
+        }
+        return r;
+      }
+
+      for (auto &list_it : vals) {
+        const std::string &key = list_it.first;
+
+        if (0 != key.compare(0, prefix.size(), prefix)) {
+          break;
+        }
+
+        cls::rbd::MirrorImageSiteStatusOnDisk status;
+        try {
+          auto it = list_it.second.cbegin();
+          status.decode_meta(it);
+        } catch (const ceph::buffer::error &err) {
+          CLS_ERR("could not decode status metadata for mirrored image '%s'",
+                  key.c_str());
+          return -EIO;
+        }
+
+        if (watchers.find(status.origin) == watchers.end()) {
+          CLS_LOG(20, "removing stale status object for key %s",
+                  key.c_str());
+          int r1 = cls_cxx_map_remove_key(hctx, key);
+          if (r1 < 0) {
+            CLS_ERR("error removing stale status for key '%s': %s",
+                    key.c_str(), cpp_strerror(r1).c_str());
+            return r1;
+          }
+        }
+      }
+
+      if (!vals.empty()) {
+        last_read = vals.rbegin()->first;
+      }
+    }
+  }
+
+  return 0;
+}
+
+int image_instance_get(cls_method_context_t hctx,
+                       const string &global_image_id,
+                       const std::set<entity_inst_t> &watchers,
+                       entity_inst_t *instance) {
+  // instance details only available for local site
+  bufferlist bl;
+  int r = cls_cxx_map_get_val(
+    hctx, status_global_key(global_image_id,
+                            cls::rbd::MirrorImageSiteStatus::LOCAL_MIRROR_UUID),
+    &bl);
+  if (r < 0) {
+    if (r != -ENOENT) {
+      CLS_ERR("error reading status for mirrored image, global id '%s': '%s'",
+              global_image_id.c_str(), cpp_strerror(r).c_str());
+    }
+    return r;
+  }
+
+  cls::rbd::MirrorImageSiteStatusOnDisk ondisk_status;
+  try {
+    auto it = bl.cbegin();
+    decode(ondisk_status, it);
+  } catch (const ceph::buffer::error &err) {
+    CLS_ERR("could not decode status for mirrored image, global id '%s'",
+            global_image_id.c_str());
+    return -EIO;
+  }
+
+  if (watchers.find(ondisk_status.origin) == watchers.end()) {
+    return -ESTALE;
+  }
+
+  *instance = ondisk_status.origin;
+  return 0;
+}
+
+int image_instance_list(cls_method_context_t hctx,
+                        const std::string &start_after,
+                        uint64_t max_return,
+                        map<std::string, entity_inst_t> *instances) {
+  std::string last_read = image_key(start_after);
+  int max_read = RBD_MAX_KEYS_READ;
+  bool more = true;
+
+  std::set<entity_inst_t> watchers;
+  int r = list_watchers(hctx, &watchers);
+  if (r < 0) {
+    return r;
+  }
+
+  while (more && instances->size() < max_return) {
+    std::map<std::string, bufferlist> vals;
+    CLS_LOG(20, "last_read = '%s'", last_read.c_str());
+    r = cls_cxx_map_get_vals(hctx, last_read, IMAGE_KEY_PREFIX, max_read, &vals,
+                             &more);
+    if (r < 0) {
+      if (r != -ENOENT) {
+        CLS_ERR("error reading mirror image directory by name: %s",
+                cpp_strerror(r).c_str());
+      }
+      return r;
+    }
+
+    for (auto it = vals.begin(); it != vals.end() &&
+           instances->size() < max_return; ++it) {
+      const std::string &image_id = it->first.substr(IMAGE_KEY_PREFIX.size());
+      cls::rbd::MirrorImage mirror_image;
+      auto iter = it->second.cbegin();
+      try {
+        decode(mirror_image, iter);
+      } catch (const ceph::buffer::error &err) {
+        CLS_ERR("could not decode mirror image payload of image '%s'",
+                image_id.c_str());
+        return -EIO;
+      }
+
+      entity_inst_t instance;
+      r = image_instance_get(hctx, mirror_image.global_image_id, watchers,
+                             &instance);
+      if (r < 0) {
+        continue;
+      }
+
+      (*instances)[image_id] = instance;
+    }
+    if (!vals.empty()) {
+      last_read = vals.rbegin()->first;
+    }
+  }
+
+  return 0;
+}
+
+int instances_list(cls_method_context_t hctx,
+                   std::vector<std::string> *instance_ids) {
+  std::string last_read = INSTANCE_KEY_PREFIX;
+  int max_read = RBD_MAX_KEYS_READ;
+  bool more = true;
+  while (more) {
+    std::map<std::string, bufferlist> vals;
+    int r = cls_cxx_map_get_vals(hctx, last_read, INSTANCE_KEY_PREFIX.c_str(),
+                                 max_read, &vals, &more);
+    if (r < 0) {
+      if (r != -ENOENT) {
+	CLS_ERR("error reading mirror instances: %s", cpp_strerror(r).c_str());
+      }
+      return r;
+    }
+
+    for (auto &it : vals) {
+      instance_ids->push_back(it.first.substr(INSTANCE_KEY_PREFIX.size()));
+    }
+
+    if (!vals.empty()) {
+      last_read = vals.rbegin()->first;
+    }
+  }
+  return 0;
+}
+
+int instances_add(cls_method_context_t hctx, const string &instance_id) {
+  bufferlist bl;
+
+  int r = cls_cxx_map_set_val(hctx, instance_key(instance_id), &bl);
+  if (r < 0) {
+    CLS_ERR("error setting mirror instance %s: %s", instance_id.c_str(),
+            cpp_strerror(r).c_str());
+    return r;
+  }
+  return 0;
+}
+
+int instances_remove(cls_method_context_t hctx, const string &instance_id) {
+
+  int r = cls_cxx_map_remove_key(hctx, instance_key(instance_id));
+  if (r < 0) {
+    CLS_ERR("error removing mirror instance %s: %s", instance_id.c_str(),
+            cpp_strerror(r).c_str());
+    return r;
+  }
+  return 0;
+}
+
+int mirror_image_map_list(cls_method_context_t hctx,
+                          const std::string &start_after,
+                          uint64_t max_return,
+                          std::map<std::string, cls::rbd::MirrorImageMap> *image_mapping) {
+  bool more = true;
+  std::string last_read = mirror_image_map_key(start_after);
+
+  while (more && image_mapping->size() < max_return) {
+    std::map<std::string, bufferlist> vals;
+    CLS_LOG(20, "last read: '%s'", last_read.c_str());
+
+    int max_read = std::min<uint64_t>(RBD_MAX_KEYS_READ, max_return - image_mapping->size());
+    int r = cls_cxx_map_get_vals(hctx, last_read, MIRROR_IMAGE_MAP_KEY_PREFIX,
+                                 max_read, &vals, &more);
+    if (r < 0) {
+      CLS_ERR("error reading image map: %s", cpp_strerror(r).c_str());
+      return r;
+    }
+
+    if (vals.empty()) {
+      return 0;
+    }
+
+    for (auto it = vals.begin(); it != vals.end(); ++it) {
+      const std::string &global_image_id =
+        it->first.substr(MIRROR_IMAGE_MAP_KEY_PREFIX.size());
+
+      cls::rbd::MirrorImageMap mirror_image_map;
+      auto iter = it->second.cbegin();
+      try {
+        decode(mirror_image_map, iter);
+      } catch (const ceph::buffer::error &err) {
+        CLS_ERR("could not decode image map payload: %s",
+                cpp_strerror(r).c_str());
+        return -EINVAL;
+      }
+
+      image_mapping->insert(std::make_pair(global_image_id, mirror_image_map));
+    }
+
+    if (!vals.empty()) {
+      last_read = vals.rbegin()->first;
+    }
+  }
+
+  return 0;
+}
+
+int image_snapshot_unlink_peer(cls_method_context_t hctx,
+                               uint64_t snap_id,
+                               std::string mirror_peer_uuid) {
+  cls_rbd_snap snap;
+  std::string snap_key;
+  key_from_snap_id(snap_id, &snap_key);
+  int r = read_key(hctx, snap_key, &snap);
+  if (r < 0) {
+    if (r != -ENOENT) {
+      CLS_ERR("Could not read snapshot meta off disk: %s",
+              cpp_strerror(r).c_str());
+    }
+    return r;
+  }
+
+  auto mirror_ns = boost::get<cls::rbd::MirrorSnapshotNamespace>(
+    &snap.snapshot_namespace);
+  if (mirror_ns == nullptr) {
+    CLS_LOG(5, "mirror_image_snapshot_unlink_peer " \
+            "not mirroring snapshot snap_id=%" PRIu64, snap_id);
+    return -EINVAL;
+  }
+
+  if (mirror_ns->mirror_peer_uuids.count(mirror_peer_uuid) == 0) {
+    return -ENOENT;
+  }
+
+  if (mirror_ns->mirror_peer_uuids.size() == 1) {
+    // if this is the last peer to unlink and we have at least one additional
+    // newer mirror snapshot, return a special error to inform the caller it
+    // should remove the snapshot instead.
+    auto search_lambda = [snap_id](const cls_rbd_snap& snap_meta) {
+      if (snap_meta.id > snap_id &&
+          boost::get<cls::rbd::MirrorSnapshotNamespace>(
+                   &snap_meta.snapshot_namespace) != nullptr) {
+        return -EEXIST;
+      }
+      return 0;
+    };
+    r = image::snapshot::iterate(hctx, search_lambda);
+    if (r == -EEXIST) {
+      return -ERESTART;
+    }
+  }
+
+  mirror_ns->mirror_peer_uuids.erase(mirror_peer_uuid);
+
+  r = image::snapshot::write(hctx, snap_key, std::move(snap));
+  if (r < 0) {
+    return r;
+  }
+
+  return 0;
+}
+
+int image_snapshot_set_copy_progress(cls_method_context_t hctx,
+                                     uint64_t snap_id, bool complete,
+                                     uint64_t last_copied_object_number) {
+  cls_rbd_snap snap;
+  std::string snap_key;
+  key_from_snap_id(snap_id, &snap_key);
+  int r = read_key(hctx, snap_key, &snap);
+  if (r < 0) {
+    if (r != -ENOENT) {
+      CLS_ERR("Could not read snapshot meta off disk: %s",
+              cpp_strerror(r).c_str());
+    }
+    return r;
+  }
+
+  auto mirror_ns = boost::get<cls::rbd::MirrorSnapshotNamespace>(
+    &snap.snapshot_namespace);
+  if (mirror_ns == nullptr) {
+    CLS_LOG(5, "mirror_image_snapshot_set_copy_progress " \
+            "not mirroring snapshot snap_id=%" PRIu64, snap_id);
+    return -EINVAL;
+  }
+
+  mirror_ns->complete = complete;
+  if (mirror_ns->state == cls::rbd::MIRROR_SNAPSHOT_STATE_NON_PRIMARY ||
+      mirror_ns->state == cls::rbd::MIRROR_SNAPSHOT_STATE_NON_PRIMARY_DEMOTED) {
+    mirror_ns->last_copied_object_number = last_copied_object_number;
+  }
+
+  r = image::snapshot::write(hctx, snap_key, std::move(snap));
+  if (r < 0) {
+    return r;
+  }
+
+  return 0;
+}
+
+} // namespace mirror
+
+/**
+ * Input:
+ * none
+ *
+ * Output:
+ * @param uuid (std::string)
+ * @returns 0 on success, negative error code on failure
+ */
+int mirror_uuid_get(cls_method_context_t hctx, bufferlist *in,
+                    bufferlist *out) {
+  std::string mirror_uuid;
+  int r = mirror::uuid_get(hctx, &mirror_uuid);
+  if (r < 0) {
+    return r;
+  }
+
+  encode(mirror_uuid, *out);
+  return 0;
+}
+
+/**
+ * Input:
+ * @param mirror_uuid (std::string)
+ *
+ * Output:
+ * @returns 0 on success, negative error code on failure
+ */
+int mirror_uuid_set(cls_method_context_t hctx, bufferlist *in,
+                    bufferlist *out) {
+  std::string mirror_uuid;
+  try {
+    auto bl_it = in->cbegin();
+    decode(mirror_uuid, bl_it);
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+
+  if (mirror_uuid.empty()) {
+    CLS_ERR("cannot set empty mirror uuid");
+    return -EINVAL;
+  }
+
+  uint32_t mirror_mode;
+  int r = read_key(hctx, mirror::MODE, &mirror_mode);
+  if (r < 0 && r != -ENOENT) {
+    return r;
+  } else if (r == 0 && mirror_mode != cls::rbd::MIRROR_MODE_DISABLED) {
+    CLS_ERR("cannot set mirror uuid while mirroring enabled");
+    return -EINVAL;
+  }
+
+  bufferlist mirror_uuid_bl;
+  mirror_uuid_bl.append(mirror_uuid);
+  r = cls_cxx_map_set_val(hctx, mirror::UUID, &mirror_uuid_bl);
+  if (r < 0) {
+    CLS_ERR("failed to set mirror uuid");
+    return r;
+  }
+  return 0;
+}
+
+/**
+ * Input:
+ * none
+ *
+ * Output:
+ * @param cls::rbd::MirrorMode (uint32_t)
+ * @returns 0 on success, negative error code on failure
+ */
+int mirror_mode_get(cls_method_context_t hctx, bufferlist *in,
+                    bufferlist *out) {
+  uint32_t mirror_mode_decode;
+  int r = read_key(hctx, mirror::MODE, &mirror_mode_decode);
+  if (r < 0) {
+    return r;
+  }
+
+  encode(mirror_mode_decode, *out);
+  return 0;
+}
+
+/**
+ * Input:
+ * @param mirror_mode (cls::rbd::MirrorMode) (uint32_t)
+ *
+ * Output:
+ * @returns 0 on success, negative error code on failure
+ */
+int mirror_mode_set(cls_method_context_t hctx, bufferlist *in,
+                    bufferlist *out) {
+  uint32_t mirror_mode_decode;
+  try {
+    auto bl_it = in->cbegin();
+    decode(mirror_mode_decode, bl_it);
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+
+  bool enabled;
+  switch (static_cast<cls::rbd::MirrorMode>(mirror_mode_decode)) {
+  case cls::rbd::MIRROR_MODE_DISABLED:
+    enabled = false;
+    break;
+  case cls::rbd::MIRROR_MODE_IMAGE:
+  case cls::rbd::MIRROR_MODE_POOL:
+    enabled = true;
+    break;
+  default:
+    CLS_ERR("invalid mirror mode: %d", mirror_mode_decode);
+    return -EINVAL;
+  }
+
+  int r;
+  if (enabled) {
+    std::string mirror_uuid;
+    r = mirror::uuid_get(hctx, &mirror_uuid);
+    if (r == -ENOENT) {
+      return -EINVAL;
+    } else if (r < 0) {
+      return r;
+    }
+
+    bufferlist bl;
+    encode(mirror_mode_decode, bl);
+
+    r = cls_cxx_map_set_val(hctx, mirror::MODE, &bl);
+    if (r < 0) {
+      CLS_ERR("error enabling mirroring: %s", cpp_strerror(r).c_str());
+      return r;
+    }
+  } else {
+    std::vector<cls::rbd::MirrorPeer> peers;
+    r = mirror::read_peers(hctx, &peers);
+    if (r < 0 && r != -ENOENT) {
+      return r;
+    }
+
+    if (!peers.empty()) {
+      CLS_ERR("mirroring peers still registered");
+      return -EBUSY;
+    }
+
+    r = remove_key(hctx, mirror::MODE);
+    if (r < 0) {
+      return r;
+    }
+
+    r = remove_key(hctx, mirror::UUID);
+    if (r < 0) {
+      return r;
+    }
+  }
+  return 0;
+}
+
+/**
+ * Input:
+ * @param unique peer site name (std::string)
+ * @param mirror_uuid (std::string)
+ * @param direction (MirrorPeerDirection) -- future use
+ *
+ * Output:
+ * @returns 0 on success, negative error code on failure
+ */
+int mirror_peer_ping(cls_method_context_t hctx, bufferlist *in,
+                     bufferlist *out) {
+  std::string site_name;
+  std::string mirror_uuid;
+  cls::rbd::MirrorPeerDirection mirror_peer_direction;
+  try {
+    auto it = in->cbegin();
+    decode(site_name, it);
+    decode(mirror_uuid, it);
+
+    uint8_t direction;
+    decode(direction, it);
+    mirror_peer_direction = static_cast<cls::rbd::MirrorPeerDirection>(
+      direction);
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+
+  if (mirror_peer_direction != cls::rbd::MIRROR_PEER_DIRECTION_TX) {
+    return -EINVAL;
+  }
+
+  int r = mirror::peer_ping(hctx, site_name, mirror_uuid);
+  if (r < 0) {
+    return r;
+  }
+
+  return 0;
+}
+
+/**
+ * Input:
+ * none
+ *
+ * Output:
+ * @param std::vector<cls::rbd::MirrorPeer>: collection of peers
+ * @returns 0 on success, negative error code on failure
+ */
+int mirror_peer_list(cls_method_context_t hctx, bufferlist *in,
+                     bufferlist *out) {
+  std::vector<cls::rbd::MirrorPeer> peers;
+  int r = mirror::read_peers(hctx, &peers);
+  if (r < 0 && r != -ENOENT) {
+    return r;
+  }
+
+  encode(peers, *out);
+  return 0;
+}
+
+/**
+ * Input:
+ * @param mirror_peer (cls::rbd::MirrorPeer)
+ *
+ * Output:
+ * @returns 0 on success, negative error code on failure
+ */
+int mirror_peer_add(cls_method_context_t hctx, bufferlist *in,
+                    bufferlist *out) {
+  cls::rbd::MirrorPeer mirror_peer;
+  try {
+    auto it = in->cbegin();
+    decode(mirror_peer, it);
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+
+  int r = mirror::peer_add(hctx, mirror_peer);
+  if (r < 0) {
+    return r;
+  }
+
+  return 0;
+}
+
+/**
+ * Input:
+ * @param uuid (std::string)
+ *
+ * Output:
+ * @returns 0 on success, negative error code on failure
+ */
+int mirror_peer_remove(cls_method_context_t hctx, bufferlist *in,
+                       bufferlist *out) {
+  std::string uuid;
+  try {
+    auto it = in->cbegin();
+    decode(uuid, it);
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+
+  int r = mirror::peer_remove(hctx, uuid);
+  if (r < 0) {
+    return r;
+  }
+  return 0;
+}
+
+/**
+ * Input:
+ * @param uuid (std::string)
+ * @param client_name (std::string)
+ *
+ * Output:
+ * @returns 0 on success, negative error code on failure
+ */
+int mirror_peer_set_client(cls_method_context_t hctx, bufferlist *in,
+                           bufferlist *out) {
+  std::string uuid;
+  std::string client_name;
+  try {
+    auto it = in->cbegin();
+    decode(uuid, it);
+    decode(client_name, it);
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+
+  cls::rbd::MirrorPeer peer;
+  int r = mirror::read_peer(hctx, uuid, &peer);
+  if (r < 0) {
+    return r;
+  }
+
+  peer.client_name = client_name;
+  r = mirror::write_peer(hctx, peer);
+  if (r < 0) {
+    return r;
+  }
+  return 0;
+}
+
+/**
+ * Input:
+ * @param uuid (std::string)
+ * @param site_name (std::string)
+ *
+ * Output:
+ * @returns 0 on success, negative error code on failure
+ */
+int mirror_peer_set_cluster(cls_method_context_t hctx, bufferlist *in,
+                            bufferlist *out) {
+  std::string uuid;
+  std::string site_name;
+  try {
+    auto it = in->cbegin();
+    decode(uuid, it);
+    decode(site_name, it);
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+
+  cls::rbd::MirrorPeer* peer = nullptr;
+  std::vector<cls::rbd::MirrorPeer> peers;
+  int r = mirror::read_peers(hctx, &peers);
+  if (r < 0 && r != -ENOENT) {
+    return r;
+  }
+
+  for (auto& p : peers) {
+    if (p.uuid == uuid) {
+      peer = &p;
+    } else if (p.site_name == site_name) {
+      return -EEXIST;
+    }
+  }
+
+  if (peer == nullptr) {
+    return -ENOENT;
+  }
+
+  peer->site_name = site_name;
+  r = mirror::write_peer(hctx, *peer);
+  if (r < 0) {
+    return r;
+  }
+  return 0;
+}
+
+/**
+ * Input:
+ * @param uuid (std::string)
+ * @param direction (uint8_t)
+ *
+ * Output:
+ * @returns 0 on success, negative error code on failure
+ */
+int mirror_peer_set_direction(cls_method_context_t hctx, bufferlist *in,
+                              bufferlist *out) {
+  std::string uuid;
+  cls::rbd::MirrorPeerDirection mirror_peer_direction;
+  try {
+    auto it = in->cbegin();
+    decode(uuid, it);
+    uint8_t direction;
+    decode(direction, it);
+    mirror_peer_direction = static_cast<cls::rbd::MirrorPeerDirection>(
+      direction);
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+
+  cls::rbd::MirrorPeer peer;
+  int r = mirror::read_peer(hctx, uuid, &peer);
+  if (r < 0) {
+    return r;
+  }
+
+  peer.mirror_peer_direction = mirror_peer_direction;
+  r = mirror::write_peer(hctx, peer);
+  if (r < 0) {
+    return r;
+  }
+  return 0;
+}
+
+/**
+ * Input:
+ * @param start_after which name to begin listing after
+ *        (use the empty string to start at the beginning)
+ * @param max_return the maximum number of names to list
+ *
+ * Output:
+ * @param std::map<std::string, std::string>: local id to global id map
+ * @returns 0 on success, negative error code on failure
+ */
+int mirror_image_list(cls_method_context_t hctx, bufferlist *in,
+		     bufferlist *out) {
+  std::string start_after;
+  uint64_t max_return;
+  try {
+    auto iter = in->cbegin();
+    decode(start_after, iter);
+    decode(max_return, iter);
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+
+  int max_read = RBD_MAX_KEYS_READ;
+  bool more = true;
+  std::map<std::string, std::string> mirror_images;
+  std::string last_read = mirror::image_key(start_after);
+
+  while (more && mirror_images.size() < max_return) {
+    std::map<std::string, bufferlist> vals;
+    CLS_LOG(20, "last_read = '%s'", last_read.c_str());
+    int r = cls_cxx_map_get_vals(hctx, last_read, mirror::IMAGE_KEY_PREFIX,
+                                 max_read, &vals, &more);
+    if (r < 0) {
+      if (r != -ENOENT) {
+        CLS_ERR("error reading mirror image directory by name: %s",
+                cpp_strerror(r).c_str());
+      }
+      return r;
+    }
+
+    for (auto it = vals.begin(); it != vals.end(); ++it) {
+      const std::string &image_id =
+        it->first.substr(mirror::IMAGE_KEY_PREFIX.size());
+      cls::rbd::MirrorImage mirror_image;
+      auto iter = it->second.cbegin();
+      try {
+	decode(mirror_image, iter);
+      } catch (const ceph::buffer::error &err) {
+	CLS_ERR("could not decode mirror image payload of image '%s'",
+                image_id.c_str());
+	return -EIO;
+      }
+
+      mirror_images[image_id] = mirror_image.global_image_id;
+      if (mirror_images.size() >= max_return) {
+	break;
+      }
+    }
+    if (!vals.empty()) {
+      last_read = mirror::image_key(mirror_images.rbegin()->first);
+    }
+  }
+
+  encode(mirror_images, *out);
+  return 0;
+}
+
+/**
+ * Input:
+ * @param global_id (std::string)
+ *
+ * Output:
+ * @param std::string - image id
+ * @returns 0 on success, negative error code on failure
+ */
+int mirror_image_get_image_id(cls_method_context_t hctx, bufferlist *in,
+                              bufferlist *out) {
+  std::string global_id;
+  try {
+    auto it = in->cbegin();
+    decode(global_id, it);
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+
+  std::string image_id;
+  int r = read_key(hctx, mirror::global_key(global_id), &image_id);
+  if (r < 0) {
+    if (r != -ENOENT) {
+      CLS_ERR("error retrieving image id for global id '%s': %s",
+              global_id.c_str(), cpp_strerror(r).c_str());
+    }
+    return r;
+  }
+
+  encode(image_id, *out);
+  return 0;
+}
+
+/**
+ * Input:
+ * @param image_id (std::string)
+ *
+ * Output:
+ * @param cls::rbd::MirrorImage - metadata associated with the image_id
+ * @returns 0 on success, negative error code on failure
+ */
+int mirror_image_get(cls_method_context_t hctx, bufferlist *in,
+		     bufferlist *out) {
+  string image_id;
+  try {
+    auto it = in->cbegin();
+    decode(image_id, it);
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+
+  cls::rbd::MirrorImage mirror_image;
+  int r = mirror::image_get(hctx, image_id, &mirror_image);
+  if (r < 0) {
+    return r;
+  }
+
+  encode(mirror_image, *out);
+  return 0;
+}
+
+/**
+ * Input:
+ * @param image_id (std::string)
+ * @param mirror_image (cls::rbd::MirrorImage)
+ *
+ * Output:
+ * @returns 0 on success, negative error code on failure
+ * @returns -EEXIST if there's an existing image_id with a different global_image_id
+ */
+int mirror_image_set(cls_method_context_t hctx, bufferlist *in,
+		     bufferlist *out) {
+  string image_id;
+  cls::rbd::MirrorImage mirror_image;
+  try {
+    auto it = in->cbegin();
+    decode(image_id, it);
+    decode(mirror_image, it);
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+
+  int r = mirror::image_set(hctx, image_id, mirror_image);
+  if (r < 0) {
+    return r;
+  }
+  return 0;
+}
+
+/**
+ * Input:
+ * @param image_id (std::string)
+ *
+ * Output:
+ * @returns 0 on success, negative error code on failure
+ */
+int mirror_image_remove(cls_method_context_t hctx, bufferlist *in,
+			bufferlist *out) {
+  string image_id;
+  try {
+    auto it = in->cbegin();
+    decode(image_id, it);
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+
+  int r = mirror::image_remove(hctx, image_id);
+  if (r < 0) {
+    return r;
+  }
+  return 0;
+}
+
+/**
+ * Input:
+ * @param global_image_id (std::string)
+ * @param status (cls::rbd::MirrorImageSiteStatus)
+ *
+ * Output:
+ * @returns 0 on success, negative error code on failure
+ */
+int mirror_image_status_set(cls_method_context_t hctx, bufferlist *in,
+			    bufferlist *out) {
+  string global_image_id;
+  cls::rbd::MirrorImageSiteStatus status;
+  try {
+    auto it = in->cbegin();
+    decode(global_image_id, it);
+    decode(status, it);
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+
+  int r = mirror::image_status_set(hctx, global_image_id, status);
+  if (r < 0) {
+    return r;
+  }
+  return 0;
+}
+
+/**
+ * Input:
+ * @param global_image_id (std::string)
+ *
+ * Output:
+ * @returns 0 on success, negative error code on failure
+ *
+ */
+int mirror_image_status_remove(cls_method_context_t hctx, bufferlist *in,
+			       bufferlist *out) {
+  string global_image_id;
+  try {
+    auto it = in->cbegin();
+    decode(global_image_id, it);
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+
+  int r = mirror::image_status_remove(hctx, global_image_id);
+  if (r < 0) {
+    return r;
+  }
+  return 0;
+}
+
+/**
+ * Input:
+ * @param global_image_id (std::string)
+ *
+ * Output:
+ * @param cls::rbd::MirrorImageStatus - metadata associated with the global_image_id
+ * @returns 0 on success, negative error code on failure
+ */
+int mirror_image_status_get(cls_method_context_t hctx, bufferlist *in,
+			    bufferlist *out) {
+  string global_image_id;
+  try {
+    auto it = in->cbegin();
+    decode(global_image_id, it);
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+
+  std::set<entity_inst_t> watchers;
+  int r = mirror::list_watchers(hctx, &watchers);
+  if (r < 0) {
+    return r;
+  }
+
+  cls::rbd::MirrorImageStatus status;
+  r = mirror::image_status_get(hctx, global_image_id, watchers, &status);
+  if (r < 0) {
+    return r;
+  }
+
+  encode(status, *out);
+  return 0;
+}
+
+/**
+ * Input:
+ * @param start_after which name to begin listing after
+ *        (use the empty string to start at the beginning)
+ * @param max_return the maximum number of names to list
+ *
+ * Output:
+ * @param std::map<std::string, cls::rbd::MirrorImage>: image id to image map
+ * @param std::map<std::string, cls::rbd::MirrorImageStatus>: image it to status map
+ * @returns 0 on success, negative error code on failure
+ */
+int mirror_image_status_list(cls_method_context_t hctx, bufferlist *in,
+			     bufferlist *out) {
+  std::string start_after;
+  uint64_t max_return;
+  try {
+    auto iter = in->cbegin();
+    decode(start_after, iter);
+    decode(max_return, iter);
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+
+  map<std::string, cls::rbd::MirrorImage> images;
+  map<std::string, cls::rbd::MirrorImageStatus> statuses;
+  int r = mirror::image_status_list(hctx, start_after, max_return, &images,
+				    &statuses);
+  if (r < 0) {
+    return r;
+  }
+
+  encode(images, *out);
+  encode(statuses, *out);
+  return 0;
+}
+
+/**
+ * Input:
+ * @param std::vector<cls::rbd::MirrorPeer> - optional peers (backwards compatibility)
+ *
+ * Output:
+ * @param std::map<cls::rbd::MirrorImageStatusState, int32_t>: states counts
+ * @returns 0 on success, negative error code on failure
+ */
+int mirror_image_status_get_summary(cls_method_context_t hctx, bufferlist *in,
+				    bufferlist *out) {
+  std::vector<cls::rbd::MirrorPeer> peers;
+  try {
+    auto iter = in->cbegin();
+    if (!iter.end()) {
+      decode(peers, iter);
+    }
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+
+  auto mirror_peer_direction = cls::rbd::MIRROR_PEER_DIRECTION_RX;
+  if (!peers.empty()) {
+    mirror_peer_direction = peers.begin()->mirror_peer_direction;
+  }
+
+  std::set<std::string> tx_peer_mirror_uuids;
+  for (auto& peer : peers) {
+    if (peer.mirror_peer_direction == cls::rbd::MIRROR_PEER_DIRECTION_RX) {
+      continue;
+    }
+
+    tx_peer_mirror_uuids.insert(peer.mirror_uuid);
+    if (mirror_peer_direction != cls::rbd::MIRROR_PEER_DIRECTION_RX_TX &&
+        mirror_peer_direction != peer.mirror_peer_direction) {
+      mirror_peer_direction = cls::rbd::MIRROR_PEER_DIRECTION_RX_TX;
+    }
+  }
+
+  std::map<cls::rbd::MirrorImageStatusState, int32_t> states;
+  int r = mirror::image_status_get_summary(hctx, mirror_peer_direction,
+                                           tx_peer_mirror_uuids, &states);
+  if (r < 0) {
+    return r;
+  }
+
+  encode(states, *out);
+  return 0;
+}
+
+/**
+ * Input:
+ * none
+ *
+ * Output:
+ * @returns 0 on success, negative error code on failure
+ */
+int mirror_image_status_remove_down(cls_method_context_t hctx, bufferlist *in,
+				    bufferlist *out) {
+  int r = mirror::image_status_remove_down(hctx);
+  if (r < 0) {
+    return r;
+  }
+  return 0;
+}
+
+/**
+ * Input:
+ * @param global_image_id (std::string)
+ *
+ * Output:
+ * @param entity_inst_t - instance
+ * @returns 0 on success, negative error code on failure
+ */
+int mirror_image_instance_get(cls_method_context_t hctx, bufferlist *in,
+                              bufferlist *out) {
+  string global_image_id;
+  try {
+    auto it = in->cbegin();
+    decode(global_image_id, it);
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+
+  std::set<entity_inst_t> watchers;
+  int r = mirror::list_watchers(hctx, &watchers);
+  if (r < 0) {
+    return r;
+  }
+
+  entity_inst_t instance;
+  r = mirror::image_instance_get(hctx, global_image_id, watchers, &instance);
+  if (r < 0) {
+    return r;
+  }
+
+  encode(instance, *out, cls_get_features(hctx));
+  return 0;
+}
+
+/**
+ * Input:
+ * @param start_after which name to begin listing after
+ *        (use the empty string to start at the beginning)
+ * @param max_return the maximum number of names to list
+ *
+ * Output:
+ * @param std::map<std::string, entity_inst_t>: image id to instance map
+ * @returns 0 on success, negative error code on failure
+ */
+int mirror_image_instance_list(cls_method_context_t hctx, bufferlist *in,
+                               bufferlist *out) {
+  std::string start_after;
+  uint64_t max_return;
+  try {
+    auto iter = in->cbegin();
+    decode(start_after, iter);
+    decode(max_return, iter);
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+
+  map<std::string, entity_inst_t> instances;
+  int r = mirror::image_instance_list(hctx, start_after, max_return,
+                                      &instances);
+  if (r < 0) {
+    return r;
+  }
+
+  encode(instances, *out, cls_get_features(hctx));
+  return 0;
+}
+
+/**
+ * Input:
+ * none
+ *
+ * Output:
+ * @param std::vector<std::string>: instance ids
+ * @returns 0 on success, negative error code on failure
+ */
+int mirror_instances_list(cls_method_context_t hctx, bufferlist *in,
+                          bufferlist *out) {
+  std::vector<std::string> instance_ids;
+
+  int r = mirror::instances_list(hctx, &instance_ids);
+  if (r < 0) {
+    return r;
+  }
+
+  encode(instance_ids, *out);
+  return 0;
+}
+
+/**
+ * Input:
+ * @param instance_id (std::string)
+ *
+ * Output:
+ * @returns 0 on success, negative error code on failure
+ */
+int mirror_instances_add(cls_method_context_t hctx, bufferlist *in,
+                         bufferlist *out) {
+  std::string instance_id;
+  try {
+    auto iter = in->cbegin();
+    decode(instance_id, iter);
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+
+  int r = mirror::instances_add(hctx, instance_id);
+  if (r < 0) {
+    return r;
+  }
+  return 0;
+}
+
+/**
+ * Input:
+ * @param instance_id (std::string)
+ *
+ * Output:
+ * @returns 0 on success, negative error code on failure
+ */
+int mirror_instances_remove(cls_method_context_t hctx, bufferlist *in,
+                            bufferlist *out) {
+  std::string instance_id;
+  try {
+    auto iter = in->cbegin();
+    decode(instance_id, iter);
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+
+  int r = mirror::instances_remove(hctx, instance_id);
+  if (r < 0) {
+    return r;
+  }
+  return 0;
+}
+
+/**
+ * Input:
+ * @param start_after: key to start after
+ * @param max_return: max return items
+ *
+ * Output:
+ * @param std::map<std::string, cls::rbd::MirrorImageMap>: image mapping
+ * @returns 0 on success, negative error code on failure
+ */
+int mirror_image_map_list(cls_method_context_t hctx, bufferlist *in,
+                          bufferlist *out) {
+  std::string start_after;
+  uint64_t max_return;
+  try {
+    auto it = in->cbegin();
+    decode(start_after, it);
+    decode(max_return, it);
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+
+  std::map<std::string, cls::rbd::MirrorImageMap> image_mapping;
+  int r = mirror::mirror_image_map_list(hctx, start_after, max_return, &image_mapping);
+  if (r < 0) {
+    return r;
+  }
+
+  encode(image_mapping, *out);
+  return 0;
+}
+
+/**
+ * Input:
+ * @param global_image_id: global image id
+ * @param image_map: image map
+ *
+ * Output:
+ * @returns 0 on success, negative error code on failure
+ */
+int mirror_image_map_update(cls_method_context_t hctx, bufferlist *in,
+                            bufferlist *out) {
+  std::string global_image_id;
+  cls::rbd::MirrorImageMap image_map;
+
+  try {
+    auto it = in->cbegin();
+    decode(global_image_id, it);
+    decode(image_map, it);
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+
+  bufferlist bl;
+  encode(image_map, bl);
+
+  const std::string key = mirror::mirror_image_map_key(global_image_id);
+  int r = cls_cxx_map_set_val(hctx, key, &bl);
+  if (r < 0) {
+    CLS_ERR("error updating image map %s: %s", key.c_str(),
+            cpp_strerror(r).c_str());
+    return r;
+  }
+
+  return 0;
+}
+
+/**
+ * Input:
+ * @param global_image_id: global image id
+ *
+ * Output:
+ * @returns 0 on success, negative error code on failure
+ */
+int mirror_image_map_remove(cls_method_context_t hctx, bufferlist *in,
+                            bufferlist *out) {
+  std::string global_image_id;
+
+  try {
+    auto it = in->cbegin();
+    decode(global_image_id, it);
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+
+  const std::string key = mirror::mirror_image_map_key(global_image_id);
+  int r = cls_cxx_map_remove_key(hctx, key);
+  if (r < 0 && r != -ENOENT) {
+    CLS_ERR("error removing image map %s: %s", key.c_str(),
+            cpp_strerror(r).c_str());
+    return r;
+  }
+
+  return 0;
+}
+
+
+/**
+ * Input:
+ * @param snap_id: snapshot id
+ * @param mirror_peer_uuid: mirror peer uuid
+ *
+ * Output:
+ * @returns 0 on success, negative error code on failure
+ */
+int mirror_image_snapshot_unlink_peer(cls_method_context_t hctx, bufferlist *in,
+                                      bufferlist *out) {
+  uint64_t snap_id;
+  std::string mirror_peer_uuid;
+  try {
+    auto iter = in->cbegin();
+    decode(snap_id, iter);
+    decode(mirror_peer_uuid, iter);
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+
+  CLS_LOG(20,
+          "mirror_image_snapshot_unlink_peer snap_id=%" PRIu64 " peer_uuid=%s",
+          snap_id, mirror_peer_uuid.c_str());
+
+  int r = mirror::image_snapshot_unlink_peer(hctx, snap_id, mirror_peer_uuid);
+  if (r < 0) {
+    return r;
+  }
+  return 0;
+}
+
+/**
+ * Input:
+ * @param snap_id: snapshot id
+ * @param complete: true if shapshot fully copied/complete
+ * @param last_copied_object_number: last copied object number
+ *
+ * Output:
+ * @returns 0 on success, negative error code on failure
+ */
+int mirror_image_snapshot_set_copy_progress(cls_method_context_t hctx,
+                                            bufferlist *in,
+                                            bufferlist *out) {
+  uint64_t snap_id;
+  bool complete;
+  uint64_t last_copied_object_number;
+  try {
+    auto iter = in->cbegin();
+    decode(snap_id, iter);
+    decode(complete, iter);
+    decode(last_copied_object_number, iter);
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+
+  CLS_LOG(20, "mirror_image_snapshot_set_copy_progress snap_id=%" PRIu64 \
+          " complete=%d last_copied_object_number=%" PRIu64, snap_id, complete,
+          last_copied_object_number);
+
+  int r = mirror::image_snapshot_set_copy_progress(hctx, snap_id, complete,
+                                                   last_copied_object_number);
+  if (r < 0) {
+    return r;
+  }
+  return 0;
+}
+
+namespace group {
+
+/********************** methods for rbd_group_directory ***********************/
+
+int dir_add(cls_method_context_t hctx,
+            const string &name, const string &id,
+            bool check_for_unique_id)
+{
+  if (!name.size() || !is_valid_id(id)) {
+    CLS_ERR("invalid group name '%s' or id '%s'",
+            name.c_str(), id.c_str());
+    return -EINVAL;
+  }
+
+  CLS_LOG(20, "dir_add name=%s id=%s", name.c_str(), id.c_str());
+
+  string name_key = dir_key_for_name(name);
+  string id_key = dir_key_for_id(id);
+  string tmp;
+  int r = read_key(hctx, name_key, &tmp);
+  if (r != -ENOENT) {
+    CLS_LOG(10, "name already exists");
+    return -EEXIST;
+  }
+  r = read_key(hctx, id_key, &tmp);
+  if (r != -ENOENT && check_for_unique_id) {
+    CLS_LOG(10, "id already exists");
+    return -EBADF;
+  }
+  bufferlist id_bl, name_bl;
+  encode(id, id_bl);
+  encode(name, name_bl);
+  map<string, bufferlist> omap_vals;
+  omap_vals[name_key] = id_bl;
+  omap_vals[id_key] = name_bl;
+  return cls_cxx_map_set_vals(hctx, &omap_vals);
+}
+
+int dir_remove(cls_method_context_t hctx,
+               const string &name, const string &id)
+{
+  CLS_LOG(20, "dir_remove name=%s id=%s", name.c_str(), id.c_str());
+
+  string name_key = dir_key_for_name(name);
+  string id_key = dir_key_for_id(id);
+  string stored_name, stored_id;
+
+  int r = read_key(hctx, name_key, &stored_id);
+  if (r < 0) {
+    if (r != -ENOENT)
+      CLS_ERR("error reading name to id mapping: %s", cpp_strerror(r).c_str());
+    return r;
+  }
+  r = read_key(hctx, id_key, &stored_name);
+  if (r < 0) {
+    if (r != -ENOENT)
+      CLS_ERR("error reading id to name mapping: %s", cpp_strerror(r).c_str());
+    return r;
+  }
+
+  // check if this op raced with a rename
+  if (stored_name != name || stored_id != id) {
+    CLS_ERR("stored name '%s' and id '%s' do not match args '%s' and '%s'",
+            stored_name.c_str(), stored_id.c_str(), name.c_str(), id.c_str());
+    return -ESTALE;
+  }
+
+  r = cls_cxx_map_remove_key(hctx, name_key);
+  if (r < 0) {
+    CLS_ERR("error removing name: %s", cpp_strerror(r).c_str());
+    return r;
+  }
+
+  r = cls_cxx_map_remove_key(hctx, id_key);
+  if (r < 0) {
+    CLS_ERR("error removing id: %s", cpp_strerror(r).c_str());
+    return r;
+  }
+
+  return 0;
+}
+
+static const string RBD_GROUP_SNAP_KEY_PREFIX = "snapshot_";
+
+std::string snap_key(const std::string &snap_id) {
+  ostringstream oss;
+  oss << RBD_GROUP_SNAP_KEY_PREFIX << snap_id;
+  return oss.str();
+}
+
+int snap_list(cls_method_context_t hctx, cls::rbd::GroupSnapshot start_after,
+              uint64_t max_return,
+              std::vector<cls::rbd::GroupSnapshot> *group_snaps)
+{
+  int max_read = RBD_MAX_KEYS_READ;
+  std::map<string, bufferlist> vals;
+  string last_read = snap_key(start_after.id);
+
+  group_snaps->clear();
+
+  bool more;
+  do {
+    int r = cls_cxx_map_get_vals(hctx, last_read,
+				 RBD_GROUP_SNAP_KEY_PREFIX,
+				 max_read, &vals, &more);
+    if (r < 0)
+      return r;
+
+    for (auto it = vals.begin(); it != vals.end() && group_snaps->size() < max_return; ++it) {
+
+      auto iter = it->second.cbegin();
+      cls::rbd::GroupSnapshot snap;
+      try {
+	decode(snap, iter);
+      } catch (const ceph::buffer::error &err) {
+	CLS_ERR("error decoding snapshot: %s", it->first.c_str());
+	return -EIO;
+      }
+      CLS_LOG(20, "Discovered snapshot %s %s",
+	      snap.name.c_str(),
+	      snap.id.c_str());
+      group_snaps->push_back(snap);
+    }
+
+    if (!vals.empty()) {
+      last_read = vals.rbegin()->first;
+    }
+  } while (more && (group_snaps->size() < max_return));
+
+  return 0;
+}
+
+static int check_duplicate_snap_name(cls_method_context_t hctx,
+				     const std::string &snap_name,
+				     const std::string &snap_id)
+{
+  const int max_read = 1024;
+  cls::rbd::GroupSnapshot snap_last;
+  std::vector<cls::rbd::GroupSnapshot> page;
+
+  for (;;) {
+    int r = snap_list(hctx, snap_last, max_read, &page);
+    if (r < 0) {
+      return r;
+    }
+    for (auto& snap: page) {
+      if (snap.name == snap_name && snap.id != snap_id) {
+	return -EEXIST;
+      }
+    }
+
+    if (page.size() < max_read) {
+      break;
+    }
+
+    snap_last = *page.rbegin();
+  }
+
+  return 0;
+}
+
+} // namespace group
+
+/**
+ * List groups from the directory.
+ *
+ * Input:
+ * @param start_after (std::string)
+ * @param max_return (int64_t)
+ *
+ * Output:
+ * @param map of groups (name, id)
+ * @return 0 on success, negative error code on failure
+ */
+int group_dir_list(cls_method_context_t hctx, bufferlist *in, bufferlist *out)
+{
+  string start_after;
+  uint64_t max_return;
+
+  try {
+    auto iter = in->cbegin();
+    decode(start_after, iter);
+    decode(max_return, iter);
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+
+  int max_read = RBD_MAX_KEYS_READ;
+  bool more = true;
+  map<string, string> groups;
+  string last_read = dir_key_for_name(start_after);
+
+  while (more && groups.size() < max_return) {
+    map<string, bufferlist> vals;
+    CLS_LOG(20, "last_read = '%s'", last_read.c_str());
+    int r = cls_cxx_map_get_vals(hctx, last_read, RBD_DIR_NAME_KEY_PREFIX,
+                                 max_read, &vals, &more);
+    if (r < 0) {
+      if (r != -ENOENT) {
+        CLS_ERR("error reading directory by name: %s", cpp_strerror(r).c_str());
+      }
+      return r;
+    }
+
+    for (auto val : vals) {
+      string id;
+      auto iter = val.second.cbegin();
+      try {
+	decode(id, iter);
+      } catch (const ceph::buffer::error &err) {
+	CLS_ERR("could not decode id of group '%s'", val.first.c_str());
+	return -EIO;
+      }
+      CLS_LOG(20, "adding '%s' -> '%s'", dir_name_from_key(val.first).c_str(), id.c_str());
+      groups[dir_name_from_key(val.first)] = id;
+      if (groups.size() >= max_return)
+	break;
+    }
+    if (!vals.empty()) {
+      last_read = dir_key_for_name(groups.rbegin()->first);
+    }
+  }
+
+  encode(groups, *out);
+
+  return 0;
+}
+
+/**
+ * Add a group to the directory.
+ *
+ * Input:
+ * @param name (std::string)
+ * @param id (std::string)
+ *
+ * Output:
+ * @return 0 on success, negative error code on failure
+ */
+int group_dir_add(cls_method_context_t hctx, bufferlist *in, bufferlist *out)
+{
+  int r = cls_cxx_create(hctx, false);
+
+  if (r < 0) {
+    CLS_ERR("could not create group directory: %s",
+	    cpp_strerror(r).c_str());
+    return r;
+  }
+
+  string name, id;
+  try {
+    auto iter = in->cbegin();
+    decode(name, iter);
+    decode(id, iter);
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+
+  return group::dir_add(hctx, name, id, true);
+}
+
+/**
+ * Rename a group to the directory.
+ *
+ * Input:
+ * @param src original name of the group (std::string)
+ * @param dest new name of the group (std::string)
+ * @param id the id of the group (std::string)
+ *
+ * Output:
+ * @return 0 on success, negative error code on failure
+ */
+int group_dir_rename(cls_method_context_t hctx, bufferlist *in, bufferlist *out)
+{
+  string src, dest, id;
+  try {
+    auto iter = in->cbegin();
+    decode(src, iter);
+    decode(dest, iter);
+    decode(id, iter);
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+
+  int r = group::dir_remove(hctx, src, id);
+  if (r < 0)
+    return r;
+
+  return group::dir_add(hctx, dest, id, false);
+}
+
+/**
+ * Remove a group from the directory.
+ *
+ * Input:
+ * @param name (std::string)
+ * @param id (std::string)
+ *
+ * Output:
+ * @return 0 on success, negative error code on failure
+ */
+int group_dir_remove(cls_method_context_t hctx, bufferlist *in, bufferlist *out)
+{
+  string name, id;
+  try {
+    auto iter = in->cbegin();
+    decode(name, iter);
+    decode(id, iter);
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+
+  return group::dir_remove(hctx, name, id);
+}
+
+/**
+ * Set state of an image in the group.
+ *
+ * Input:
+ * @param image_status (cls::rbd::GroupImageStatus)
+ *
+ * Output:
+ * @return 0 on success, negative error code on failure
+ */
+int group_image_set(cls_method_context_t hctx, bufferlist *in, bufferlist *out)
+{
+  CLS_LOG(20, "group_image_set");
+
+  cls::rbd::GroupImageStatus st;
+  try {
+    auto iter = in->cbegin();
+    decode(st, iter);
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+
+  string image_key = st.spec.image_key();
+
+  bufferlist image_val_bl;
+  encode(st.state, image_val_bl);
+  int r = cls_cxx_map_set_val(hctx, image_key, &image_val_bl);
+  if (r < 0) {
+    return r;
+  }
+
+  return 0;
+}
+
+/**
+ * Remove reference to an image from the group.
+ *
+ * Input:
+ * @param spec (cls::rbd::GroupImageSpec)
+ *
+ * Output:
+ * @return 0 on success, negative error code on failure
+ */
+int group_image_remove(cls_method_context_t hctx,
+                       bufferlist *in, bufferlist *out)
+{
+  CLS_LOG(20, "group_image_remove");
+  cls::rbd::GroupImageSpec spec;
+  try {
+    auto iter = in->cbegin();
+    decode(spec, iter);
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+
+  string image_key = spec.image_key();
+
+  int r = cls_cxx_map_remove_key(hctx, image_key);
+  if (r < 0) {
+    CLS_ERR("error removing image from group: %s", cpp_strerror(r).c_str());
+    return r;
+  }
+
+  return 0;
+}
+
+/*
+ * List images in the group.
+ *
+ * Input:
+ * @param start_after which name to begin listing after
+ *        (use the empty string to start at the beginning)
+ * @param max_return the maximum number of names to list
+ *
+ * Output:
+ * @param tuples of descriptions of the images: image_id, pool_id, image reference state.
+ * @return 0 on success, negative error code on failure
+ */
+int group_image_list(cls_method_context_t hctx,
+                     bufferlist *in, bufferlist *out)
+{
+  CLS_LOG(20, "group_image_list");
+  cls::rbd::GroupImageSpec start_after;
+  uint64_t max_return;
+  try {
+    auto iter = in->cbegin();
+    decode(start_after, iter);
+    decode(max_return, iter);
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+
+  int max_read = RBD_MAX_KEYS_READ;
+  std::map<string, bufferlist> vals;
+  string last_read = start_after.image_key();
+  std::vector<cls::rbd::GroupImageStatus> res;
+  bool more;
+  do {
+    int r = cls_cxx_map_get_vals(hctx, last_read,
+				 cls::rbd::RBD_GROUP_IMAGE_KEY_PREFIX,
+				 max_read, &vals, &more);
+    if (r < 0)
+      return r;
+
+    for (auto it = vals.begin(); it != vals.end() && res.size() < max_return; ++it) {
+
+      auto iter = it->second.cbegin();
+      cls::rbd::GroupImageLinkState state;
+      try {
+	decode(state, iter);
+      } catch (const ceph::buffer::error &err) {
+	CLS_ERR("error decoding state for image: %s", it->first.c_str());
+	return -EIO;
+      }
+      cls::rbd::GroupImageSpec spec;
+      int r = cls::rbd::GroupImageSpec::from_key(it->first, &spec);
+      if (r < 0)
+	return r;
+
+      CLS_LOG(20, "Discovered image %s %" PRId64 " %d", spec.image_id.c_str(),
+	                                         spec.pool_id,
+					         (int)state);
+      res.push_back(cls::rbd::GroupImageStatus(spec, state));
+    }
+    if (res.size() > 0) {
+      last_read = res.rbegin()->spec.image_key();
+    }
+
+  } while (more && (res.size() < max_return));
+  encode(res, *out);
+
+  return 0;
+}
+
+/**
+ * Reference the group this image belongs to.
+ *
+ * Input:
+ * @param group_id (std::string)
+ * @param pool_id (int64_t)
+ *
+ * Output:
+ * @return 0 on success, negative error code on failure
+ */
+int image_group_add(cls_method_context_t hctx,
+		    bufferlist *in, bufferlist *out)
+{
+  CLS_LOG(20, "image_group_add");
+  cls::rbd::GroupSpec new_group;
+  try {
+    auto iter = in->cbegin();
+    decode(new_group, iter);
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+
+  bufferlist existing_refbl;
+
+  int r = cls_cxx_map_get_val(hctx, RBD_GROUP_REF, &existing_refbl);
+  if (r == 0) {
+    // If we are trying to link this image to the same group then return
+    // success. If this image already belongs to another group then abort.
+    cls::rbd::GroupSpec old_group;
+    try {
+      auto iter = existing_refbl.cbegin();
+      decode(old_group, iter);
+    } catch (const ceph::buffer::error &err) {
+      return -EINVAL;
+    }
+
+    if ((old_group.group_id != new_group.group_id) ||
+        (old_group.pool_id != new_group.pool_id)) {
+      return -EEXIST;
+    } else {
+      return 0; // In this case the values are already correct
+    }
+  } else if (r < 0 && r != -ENOENT) {
+    // No entry means this image is not a member of any group.
+    return r;
+  }
+
+  r = image::set_op_features(hctx, RBD_OPERATION_FEATURE_GROUP,
+                             RBD_OPERATION_FEATURE_GROUP);
+  if (r < 0) {
+    return r;
+  }
+
+  bufferlist refbl;
+  encode(new_group, refbl);
+  r = cls_cxx_map_set_val(hctx, RBD_GROUP_REF, &refbl);
+  if (r < 0) {
+    return r;
+  }
+
+  return 0;
+}
+
+/**
+ * Remove image's pointer to the group.
+ *
+ * Input:
+ * @param cg_id (std::string)
+ * @param pool_id (int64_t)
+ *
+ * Output:
+ * @return 0 on success, negative error code on failure
+ */
+int image_group_remove(cls_method_context_t hctx,
+		       bufferlist *in,
+		       bufferlist *out)
+{
+  CLS_LOG(20, "image_group_remove");
+  cls::rbd::GroupSpec spec;
+  try {
+    auto iter = in->cbegin();
+    decode(spec, iter);
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+
+  bufferlist refbl;
+  int r = cls_cxx_map_get_val(hctx, RBD_GROUP_REF, &refbl);
+  if (r < 0) {
+    return r;
+  }
+
+  cls::rbd::GroupSpec ref_spec;
+  auto iter = refbl.cbegin();
+  try {
+    decode(ref_spec, iter);
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+
+  if (ref_spec.pool_id != spec.pool_id || ref_spec.group_id != spec.group_id) {
+    return -EBADF;
+  }
+
+  r = cls_cxx_map_remove_key(hctx, RBD_GROUP_REF);
+  if (r < 0) {
+    return r;
+  }
+
+  r = image::set_op_features(hctx, 0, RBD_OPERATION_FEATURE_GROUP);
+  if (r < 0) {
+    return r;
+  }
+
+  return 0;
+}
+
+/**
+ * Retrieve the id and pool of the group this image belongs to.
+ *
+ * Input:
+ * none
+ *
+ * Output:
+ * @param GroupSpec
+ * @return 0 on success, negative error code on failure
+ */
+int image_group_get(cls_method_context_t hctx,
+		    bufferlist *in, bufferlist *out)
+{
+  CLS_LOG(20, "image_group_get");
+  bufferlist refbl;
+  int r = cls_cxx_map_get_val(hctx, RBD_GROUP_REF, &refbl);
+  if (r < 0 && r != -ENOENT) {
+    return r;
+  }
+
+  cls::rbd::GroupSpec spec;
+
+  if (r != -ENOENT) {
+    auto iter = refbl.cbegin();
+    try {
+      decode(spec, iter);
+    } catch (const ceph::buffer::error &err) {
+      return -EINVAL;
+    }
+  }
+
+  encode(spec, *out);
+  return 0;
+}
+
+/**
+ * Save initial snapshot record.
+ *
+ * Input:
+ * @param GroupSnapshot
+ *
+ * Output:
+ * @return 0 on success, negative error code on failure
+ */
+int group_snap_set(cls_method_context_t hctx,
+		   bufferlist *in, bufferlist *out)
+{
+  CLS_LOG(20, "group_snap_set");
+  cls::rbd::GroupSnapshot group_snap;
+  try {
+    auto iter = in->cbegin();
+    decode(group_snap, iter);
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+
+  if (group_snap.name.empty()) {
+    CLS_ERR("group snapshot name is empty");
+    return -EINVAL;
+  }
+  if (group_snap.id.empty()) {
+    CLS_ERR("group snapshot id is empty");
+    return -EINVAL;
+  }
+
+  int r = group::check_duplicate_snap_name(hctx, group_snap.name,
+                                           group_snap.id);
+  if (r < 0) {
+    return r;
+  }
+
+  std::string key = group::snap_key(group_snap.id);
+  if (group_snap.state == cls::rbd::GROUP_SNAPSHOT_STATE_INCOMPLETE) {
+    bufferlist snap_bl;
+    r = cls_cxx_map_get_val(hctx, key, &snap_bl);
+    if (r < 0 && r != -ENOENT) {
+      return r;
+    } else if (r >= 0) {
+      return -EEXIST;
+    }
+  }
+
+  bufferlist obl;
+  encode(group_snap, obl);
+  r = cls_cxx_map_set_val(hctx, key, &obl);
+  return r;
+}
+
+/**
+ * Remove snapshot record.
+ *
+ * Input:
+ * @param id Snapshot id
+ *
+ * Output:
+ * @return 0 on success, negative error code on failure
+ */
+int group_snap_remove(cls_method_context_t hctx,
+		      bufferlist *in, bufferlist *out)
+{
+  CLS_LOG(20, "group_snap_remove");
+  std::string snap_id;
+  try {
+    auto iter = in->cbegin();
+    decode(snap_id, iter);
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+
+  std::string snap_key = group::snap_key(snap_id);
+
+  CLS_LOG(20, "removing snapshot with key %s", snap_key.c_str());
+  int r = cls_cxx_map_remove_key(hctx, snap_key);
+  return r;
+}
+
+/**
+ * Get group's snapshot by id.
+ *
+ * Input:
+ * @param snapshot_id the id of the snapshot to look for.
+ *
+ * Output:
+ * @param GroupSnapshot the requested snapshot
+ * @return 0 on success, negative error code on failure
+ */
+int group_snap_get_by_id(cls_method_context_t hctx,
+			 bufferlist *in, bufferlist *out)
+{
+  CLS_LOG(20, "group_snap_get_by_id");
+
+  std::string snap_id;
+  try {
+    auto iter = in->cbegin();
+    decode(snap_id, iter);
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+
+  bufferlist snapbl;
+
+  int r = cls_cxx_map_get_val(hctx, group::snap_key(snap_id), &snapbl);
+  if (r < 0) {
+    return r;
+  }
+
+  cls::rbd::GroupSnapshot group_snap;
+  auto iter = snapbl.cbegin();
+  try {
+    decode(group_snap, iter);
+  } catch (const ceph::buffer::error &err) {
+    CLS_ERR("error decoding snapshot: %s", snap_id.c_str());
+    return -EIO;
+  }
+
+  encode(group_snap, *out);
+
+  return 0;
+}
+
+/**
+ * List group's snapshots.
+ *
+ * Input:
+ * @param start_after which name to begin listing after
+ * 	  (use the empty string to start at the beginning)
+ * @param max_return the maximum number of snapshots to list
+ *
+ * Output:
+ * @param list of snapshots
+ * @return 0 on success, negative error code on failure
+ */
+int group_snap_list(cls_method_context_t hctx,
+		    bufferlist *in, bufferlist *out)
+{
+  CLS_LOG(20, "group_snap_list");
+
+  cls::rbd::GroupSnapshot start_after;
+  uint64_t max_return;
+  try {
+    auto iter = in->cbegin();
+    decode(start_after, iter);
+    decode(max_return, iter);
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+  std::vector<cls::rbd::GroupSnapshot> group_snaps;
+  group::snap_list(hctx, start_after, max_return, &group_snaps);
+
+  encode(group_snaps, *out);
+
+  return 0;
+}
+
+namespace trash {
+
+static const std::string IMAGE_KEY_PREFIX("id_");
+
+std::string image_key(const std::string &image_id) {
+  return IMAGE_KEY_PREFIX + image_id;
+}
+
+std::string image_id_from_key(const std::string &key) {
+  return key.substr(IMAGE_KEY_PREFIX.size());
+}
+
+} // namespace trash
+
+/**
+ * Add an image entry to the rbd trash. Creates the trash object if
+ * needed, and stores the trash spec information of the deleted image.
+ *
+ * Input:
+ * @param id the id of the image
+ * @param trash_spec the spec info of the deleted image
+ *
+ * Output:
+ * @returns -EEXIST if the image id is already in the trash
+ * @returns 0 on success, negative error code on failure
+ */
+int trash_add(cls_method_context_t hctx, bufferlist *in, bufferlist *out)
+{
+  int r = cls_cxx_create(hctx, false);
+  if (r < 0) {
+    CLS_ERR("could not create trash: %s", cpp_strerror(r).c_str());
+    return r;
+  }
+
+  string id;
+  cls::rbd::TrashImageSpec trash_spec;
+  try {
+    auto iter = in->cbegin();
+    decode(id, iter);
+    decode(trash_spec, iter);
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+
+  if (!is_valid_id(id)) {
+    CLS_ERR("trash_add: invalid id '%s'", id.c_str());
+    return -EINVAL;
+  }
+
+  CLS_LOG(20, "trash_add id=%s", id.c_str());
+
+  string key = trash::image_key(id);
+  cls::rbd::TrashImageSpec tmp;
+  r = read_key(hctx, key, &tmp);
+  if (r < 0 && r != -ENOENT) {
+    CLS_ERR("could not read key %s entry from trash: %s", key.c_str(),
+            cpp_strerror(r).c_str());
+    return r;
+  } else if (r == 0) {
+    CLS_LOG(10, "id already exists");
+    return -EEXIST;
+  }
+
+  map<string, bufferlist> omap_vals;
+  encode(trash_spec, omap_vals[key]);
+  return cls_cxx_map_set_vals(hctx, &omap_vals);
+}
+
+/**
+ * Removes an image entry from the rbd trash object.
+ * image.
+ *
+ * Input:
+ * @param id the id of the image
+ *
+ * Output:
+ * @returns -ENOENT if the image id does not exist in the trash
+ * @returns 0 on success, negative error code on failure
+ */
+int trash_remove(cls_method_context_t hctx, bufferlist *in, bufferlist *out)
+{
+  string id;
+  try {
+    auto iter = in->cbegin();
+    decode(id, iter);
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+
+  CLS_LOG(20, "trash_remove id=%s", id.c_str());
+
+  string key = trash::image_key(id);
+  bufferlist tmp;
+  int r = cls_cxx_map_get_val(hctx, key, &tmp);
+  if (r < 0) {
+    if (r != -ENOENT) {
+      CLS_ERR("error reading entry key %s: %s", key.c_str(), cpp_strerror(r).c_str());
+    }
+    return r;
+  }
+
+  r = cls_cxx_map_remove_key(hctx, key);
+  if (r < 0) {
+    CLS_ERR("error removing entry: %s", cpp_strerror(r).c_str());
+    return r;
+  }
+
+  return 0;
+}
+
+/**
+ * Returns the list of trash spec entries registered in the rbd_trash
+ * object.
+ *
+ * Input:
+ * @param start_after which name to begin listing after
+ *        (use the empty string to start at the beginning)
+ * @param max_return the maximum number of names to list
+ *
+ * Output:
+ * @param data the map between image id and trash spec info
+ *
+ * @returns 0 on success, negative error code on failure
+ */
+int trash_list(cls_method_context_t hctx, bufferlist *in, bufferlist *out)
+{
+  string start_after;
+  uint64_t max_return;
+
+  try {
+    auto iter = in->cbegin();
+    decode(start_after, iter);
+    decode(max_return, iter);
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+
+  map<string, cls::rbd::TrashImageSpec> data;
+  string last_read = trash::image_key(start_after);
+  bool more = true;
+
+  CLS_LOG(20, "trash_get_images");
+  while (data.size() < max_return) {
+    map<string, bufferlist> raw_data;
+    int max_read = std::min<int32_t>(RBD_MAX_KEYS_READ,
+                                     max_return - data.size());
+    int r = cls_cxx_map_get_vals(hctx, last_read, trash::IMAGE_KEY_PREFIX,
+                                 max_read, &raw_data, &more);
+    if (r < 0) {
+      if (r != -ENOENT) {
+        CLS_ERR("failed to read the vals off of disk: %s",
+                cpp_strerror(r).c_str());
+      }
+      return r;
+    }
+    if (raw_data.empty()) {
+      break;
+    }
+
+    for (auto it = raw_data.begin(); it != raw_data.end(); ++it) {
+      decode(data[trash::image_id_from_key(it->first)], it->second);
+    }
+
+    if (!more) {
+      break;
+    }
+
+    last_read = raw_data.rbegin()->first;
+  }
+
+  encode(data, *out);
+  return 0;
+}
+
+/**
+ * Returns the trash spec entry of an image registered in the rbd_trash
+ * object.
+ *
+ * Input:
+ * @param id the id of the image
+ *
+ * Output:
+ * @param out the trash spec entry
+ *
+ * @returns 0 on success, negative error code on failure
+ */
+int trash_get(cls_method_context_t hctx, bufferlist *in, bufferlist *out)
+{
+  string id;
+  try {
+    auto iter = in->cbegin();
+    decode(id, iter);
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+
+  CLS_LOG(20, "trash_get_image id=%s", id.c_str());
+
+
+  string key = trash::image_key(id);
+  bufferlist bl;
+  int r = cls_cxx_map_get_val(hctx, key, out);
+  if (r < 0 && r != -ENOENT) {
+    CLS_ERR("error reading image from trash '%s': '%s'", id.c_str(),
+            cpp_strerror(r).c_str());
+  }
+  return r;
+}
+
+/**
+ * Set state of an image in the rbd_trash object.
+ *
+ * Input:
+ * @param id the id of the image
+ * @param trash_state the state of the image to be set
+ * @param expect_state the expected state of the image
+ *
+ * Output:
+ * @returns 0 on success, negative error code on failure
+ */
+int trash_state_set(cls_method_context_t hctx, bufferlist *in, bufferlist *out)
+{
+  string id;
+  cls::rbd::TrashImageState trash_state;
+  cls::rbd::TrashImageState expect_state;
+  try {
+    auto iter = in->cbegin();
+    decode(id, iter);
+    decode(trash_state, iter);
+    decode(expect_state, iter);
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+
+  CLS_LOG(20, "trash_state_set id=%s", id.c_str());
+
+  string key = trash::image_key(id);
+  cls::rbd::TrashImageSpec trash_spec;
+  int r = read_key(hctx, key, &trash_spec);
+  if (r < 0) {
+    if (r != -ENOENT) {
+      CLS_ERR("Could not read trash image spec off disk: %s",
+              cpp_strerror(r).c_str());
+    }
+    return r;
+  }
+
+  if (trash_spec.state == expect_state) {
+    trash_spec.state = trash_state;
+    r = write_key(hctx, key, trash_spec);
+    if (r < 0) {
+      CLS_ERR("error setting trash image state: %s", cpp_strerror(r).c_str());
+      return r;
+    }
+
+    return 0;
+  } else if (trash_spec.state == trash_state) {
+    return 0;
+  } else {
+    CLS_ERR("Current trash state: %d do not match expected: %d or set: %d",
+            trash_spec.state, expect_state, trash_state);
+    return -ESTALE;
+  }
+}
+
+namespace nspace {
+
+const std::string NAME_KEY_PREFIX("name_");
+
+std::string key_for_name(const std::string& name) {
+  return NAME_KEY_PREFIX + name;
+}
+
+std::string name_from_key(const std::string &key) {
+  return key.substr(NAME_KEY_PREFIX.size());
+}
+
+} // namespace nspace
+
+/**
+ * Add a namespace to the namespace directory.
+ *
+ * Input:
+ * @param name the name of the namespace
+ *
+ * Output:
+ * @returns -EEXIST if the namespace is already exists
+ * @returns 0 on success, negative error code on failure
+ */
+int namespace_add(cls_method_context_t hctx, bufferlist *in, bufferlist *out)
+{
+  std::string name;
+  try {
+    auto iter = in->cbegin();
+    decode(name, iter);
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+
+  std::string key(nspace::key_for_name(name));
+  bufferlist value;
+  int r = cls_cxx_map_get_val(hctx, key, &value);
+  if (r < 0 && r != -ENOENT) {
+    return r;
+  } else if (r == 0) {
+    return -EEXIST;
+  }
+
+  r = cls_cxx_map_set_val(hctx, key, &value);
+  if (r < 0) {
+    CLS_ERR("failed to set omap key: %s", key.c_str());
+    return r;
+  }
+
+  return 0;
+}
+
+/**
+ * Remove a namespace from the namespace directory.
+ *
+ * Input:
+ * @param name the name of the namespace
+ *
+ * Output:
+ * @returns 0 on success, negative error code on failure
+ */
+int namespace_remove(cls_method_context_t hctx, bufferlist *in, bufferlist *out)
+{
+  std::string name;
+  try {
+    auto iter = in->cbegin();
+    decode(name, iter);
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+
+  std::string key(nspace::key_for_name(name));
+  bufferlist bl;
+  int r = cls_cxx_map_get_val(hctx, key, &bl);
+  if (r < 0) {
+    return r;
+  }
+
+  r = cls_cxx_map_remove_key(hctx, key);
+  if (r < 0) {
+    return r;
+  }
+
+  return 0;
+}
+
+/**
+ * Returns the list of namespaces in the rbd_namespace object
+ *
+ * Input:
+ * @param start_after which name to begin listing after
+ *        (use the empty string to start at the beginning)
+ * @param max_return the maximum number of names to list
+ *
+ * Output:
+ * @param data list of namespace names
+ * @returns 0 on success, negative error code on failure
+ */
+int namespace_list(cls_method_context_t hctx, bufferlist *in, bufferlist *out)
+{
+  string start_after;
+  uint64_t max_return;
+  try {
+    auto iter = in->cbegin();
+    decode(start_after, iter);
+    decode(max_return, iter);
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+
+  std::list<std::string> data;
+  std::string last_read = nspace::key_for_name(start_after);
+  bool more = true;
+
+  CLS_LOG(20, "namespace_list");
+  while (data.size() < max_return) {
+    std::map<std::string, bufferlist> raw_data;
+    int max_read = std::min<int32_t>(RBD_MAX_KEYS_READ,
+                                     max_return - data.size());
+    int r = cls_cxx_map_get_vals(hctx, last_read, nspace::NAME_KEY_PREFIX,
+                                 max_read, &raw_data, &more);
+    if (r < 0) {
+      if (r != -ENOENT) {
+        CLS_ERR("failed to read the vals off of disk: %s",
+                cpp_strerror(r).c_str());
+      }
+      return r;
+    }
+
+    for (auto& it : raw_data) {
+      data.push_back(nspace::name_from_key(it.first));
+    }
+
+    if (raw_data.empty() || !more) {
+      break;
+    }
+
+    last_read = raw_data.rbegin()->first;
+  }
+
+  encode(data, *out);
+  return 0;
+}
+
+/**
+ *  Reclaim space for zeroed extents
+ *
+ * Input:
+ * @param sparse_size minimal zeroed block to sparse
+ * @param remove_empty boolean, true if the object should be removed if empty
+ *
+ * Output:
+ * @returns -ENOENT if the object does not exist or has been removed
+ * @returns 0 on success, negative error code on failure
+ */
+int sparsify(cls_method_context_t hctx, bufferlist *in, bufferlist *out)
+{
+  size_t sparse_size;
+  bool remove_empty;
+  try {
+    auto iter = in->cbegin();
+    decode(sparse_size, iter);
+    decode(remove_empty, iter);
+  } catch (const ceph::buffer::error &err) {
+    return -EINVAL;
+  }
+
+  int r = check_exists(hctx);
+  if (r < 0) {
+    return r;
+  }
+
+  bufferlist bl;
+  r = cls_cxx_read(hctx, 0, 0, &bl);
+  if (r < 0) {
+    CLS_ERR("failed to read data off of disk: %s", cpp_strerror(r).c_str());
+    return r;
+  }
+
+  if (bl.is_zero()) {
+    if (remove_empty) {
+      CLS_LOG(20, "remove");
+      r = cls_cxx_remove(hctx);
+      if (r < 0) {
+        CLS_ERR("remove failed: %s", cpp_strerror(r).c_str());
+        return r;
+      }
+    } else if (bl.length() > 0) {
+      CLS_LOG(20, "truncate");
+      bufferlist write_bl;
+      r = cls_cxx_replace(hctx, 0, 0, &write_bl);
+      if (r < 0) {
+        CLS_ERR("truncate failed: %s", cpp_strerror(r).c_str());
+        return r;
+      }
+    } else {
+      CLS_LOG(20, "skip empty");
+    }
+    return 0;
+  }
+
+  bl.rebuild(ceph::buffer::ptr_node::create(bl.length()));
+  size_t write_offset = 0;
+  size_t write_length = 0;
+  size_t offset = 0;
+  size_t length = bl.length();
+  const auto& ptr = bl.front();
+  bool replace = true;
+  while (offset < length) {
+    if (calc_sparse_extent(ptr, sparse_size, length, &write_offset,
+                           &write_length, &offset)) {
+      if (write_offset == 0 && write_length == length) {
+        CLS_LOG(20, "nothing to do");
+        return 0;
+      }
+      CLS_LOG(20, "write%s %" PRIu64 "~%" PRIu64, (replace ? "(replace)" : ""),
+              write_offset, write_length);
+      bufferlist write_bl;
+      write_bl.push_back(ceph::buffer::ptr_node::create(ptr, write_offset,
+							write_length));
+      if (replace) {
+	r = cls_cxx_replace(hctx, write_offset, write_length, &write_bl);
+        replace = false;
+      } else {
+        r = cls_cxx_write(hctx, write_offset, write_length, &write_bl);
+      }
+      if (r < 0) {
+        CLS_ERR("write failed: %s", cpp_strerror(r).c_str());
+        return r;
+      }
+      write_offset = offset;
+      write_length = 0;
+    }
+  }
+
+  return 0;
+}
+
+CLS_INIT(rbd)
+{
+  CLS_LOG(20, "Loaded rbd class!");
+
+  cls_handle_t h_class;
+  cls_method_handle_t h_create;
+  cls_method_handle_t h_get_features;
+  cls_method_handle_t h_set_features;
+  cls_method_handle_t h_get_size;
+  cls_method_handle_t h_set_size;
+  cls_method_handle_t h_get_parent;
+  cls_method_handle_t h_set_parent;
+  cls_method_handle_t h_remove_parent;
+  cls_method_handle_t h_parent_get;
+  cls_method_handle_t h_parent_overlap_get;
+  cls_method_handle_t h_parent_attach;
+  cls_method_handle_t h_parent_detach;
+  cls_method_handle_t h_get_protection_status;
+  cls_method_handle_t h_set_protection_status;
+  cls_method_handle_t h_get_stripe_unit_count;
+  cls_method_handle_t h_set_stripe_unit_count;
+  cls_method_handle_t h_get_create_timestamp;
+  cls_method_handle_t h_get_access_timestamp;
+  cls_method_handle_t h_get_modify_timestamp;
+  cls_method_handle_t h_get_flags;
+  cls_method_handle_t h_set_flags;
+  cls_method_handle_t h_op_features_get;
+  cls_method_handle_t h_op_features_set;
+  cls_method_handle_t h_add_child;
+  cls_method_handle_t h_remove_child;
+  cls_method_handle_t h_get_children;
+  cls_method_handle_t h_get_snapcontext;
+  cls_method_handle_t h_get_object_prefix;
+  cls_method_handle_t h_get_data_pool;
+  cls_method_handle_t h_get_snapshot_name;
+  cls_method_handle_t h_get_snapshot_timestamp;
+  cls_method_handle_t h_snapshot_get;
+  cls_method_handle_t h_snapshot_add;
+  cls_method_handle_t h_snapshot_remove;
+  cls_method_handle_t h_snapshot_rename;
+  cls_method_handle_t h_snapshot_trash_add;
+  cls_method_handle_t h_get_all_features;
+  cls_method_handle_t h_get_id;
+  cls_method_handle_t h_set_id;
+  cls_method_handle_t h_set_modify_timestamp;
+  cls_method_handle_t h_set_access_timestamp;
+  cls_method_handle_t h_dir_get_id;
+  cls_method_handle_t h_dir_get_name;
+  cls_method_handle_t h_dir_list;
+  cls_method_handle_t h_dir_add_image;
+  cls_method_handle_t h_dir_remove_image;
+  cls_method_handle_t h_dir_rename_image;
+  cls_method_handle_t h_dir_state_assert;
+  cls_method_handle_t h_dir_state_set;
+  cls_method_handle_t h_object_map_load;
+  cls_method_handle_t h_object_map_save;
+  cls_method_handle_t h_object_map_resize;
+  cls_method_handle_t h_object_map_update;
+  cls_method_handle_t h_object_map_snap_add;
+  cls_method_handle_t h_object_map_snap_remove;
+  cls_method_handle_t h_metadata_set;
+  cls_method_handle_t h_metadata_remove;
+  cls_method_handle_t h_metadata_list;
+  cls_method_handle_t h_metadata_get;
+  cls_method_handle_t h_snapshot_get_limit;
+  cls_method_handle_t h_snapshot_set_limit;
+  cls_method_handle_t h_child_attach;
+  cls_method_handle_t h_child_detach;
+  cls_method_handle_t h_children_list;
+  cls_method_handle_t h_migration_set;
+  cls_method_handle_t h_migration_set_state;
+  cls_method_handle_t h_migration_get;
+  cls_method_handle_t h_migration_remove;
+  cls_method_handle_t h_old_snapshots_list;
+  cls_method_handle_t h_old_snapshot_add;
+  cls_method_handle_t h_old_snapshot_remove;
+  cls_method_handle_t h_old_snapshot_rename;
+  cls_method_handle_t h_mirror_uuid_get;
+  cls_method_handle_t h_mirror_uuid_set;
+  cls_method_handle_t h_mirror_mode_get;
+  cls_method_handle_t h_mirror_mode_set;
+  cls_method_handle_t h_mirror_peer_ping;
+  cls_method_handle_t h_mirror_peer_list;
+  cls_method_handle_t h_mirror_peer_add;
+  cls_method_handle_t h_mirror_peer_remove;
+  cls_method_handle_t h_mirror_peer_set_client;
+  cls_method_handle_t h_mirror_peer_set_cluster;
+  cls_method_handle_t h_mirror_peer_set_direction;
+  cls_method_handle_t h_mirror_image_list;
+  cls_method_handle_t h_mirror_image_get_image_id;
+  cls_method_handle_t h_mirror_image_get;
+  cls_method_handle_t h_mirror_image_set;
+  cls_method_handle_t h_mirror_image_remove;
+  cls_method_handle_t h_mirror_image_status_set;
+  cls_method_handle_t h_mirror_image_status_remove;
+  cls_method_handle_t h_mirror_image_status_get;
+  cls_method_handle_t h_mirror_image_status_list;
+  cls_method_handle_t h_mirror_image_status_get_summary;
+  cls_method_handle_t h_mirror_image_status_remove_down;
+  cls_method_handle_t h_mirror_image_instance_get;
+  cls_method_handle_t h_mirror_image_instance_list;
+  cls_method_handle_t h_mirror_instances_list;
+  cls_method_handle_t h_mirror_instances_add;
+  cls_method_handle_t h_mirror_instances_remove;
+  cls_method_handle_t h_mirror_image_map_list;
+  cls_method_handle_t h_mirror_image_map_update;
+  cls_method_handle_t h_mirror_image_map_remove;
+  cls_method_handle_t h_mirror_image_snapshot_unlink_peer;
+  cls_method_handle_t h_mirror_image_snapshot_set_copy_progress;
+  cls_method_handle_t h_group_dir_list;
+  cls_method_handle_t h_group_dir_add;
+  cls_method_handle_t h_group_dir_remove;
+  cls_method_handle_t h_group_dir_rename;
+  cls_method_handle_t h_group_image_remove;
+  cls_method_handle_t h_group_image_list;
+  cls_method_handle_t h_group_image_set;
+  cls_method_handle_t h_image_group_add;
+  cls_method_handle_t h_image_group_remove;
+  cls_method_handle_t h_image_group_get;
+  cls_method_handle_t h_group_snap_set;
+  cls_method_handle_t h_group_snap_remove;
+  cls_method_handle_t h_group_snap_get_by_id;
+  cls_method_handle_t h_group_snap_list;
+  cls_method_handle_t h_trash_add;
+  cls_method_handle_t h_trash_remove;
+  cls_method_handle_t h_trash_list;
+  cls_method_handle_t h_trash_get;
+  cls_method_handle_t h_trash_state_set;
+  cls_method_handle_t h_namespace_add;
+  cls_method_handle_t h_namespace_remove;
+  cls_method_handle_t h_namespace_list;
+  cls_method_handle_t h_copyup;
+  cls_method_handle_t h_sparse_copyup;
+  cls_method_handle_t h_assert_snapc_seq;
+  cls_method_handle_t h_sparsify;
+
+  cls_register("rbd", &h_class);
+  cls_register_cxx_method(h_class, "create",
+			  CLS_METHOD_RD | CLS_METHOD_WR,
+			  create, &h_create);
+  cls_register_cxx_method(h_class, "get_features",
+			  CLS_METHOD_RD,
+			  get_features, &h_get_features);
+  cls_register_cxx_method(h_class, "set_features",
+			  CLS_METHOD_RD | CLS_METHOD_WR,
+			  set_features, &h_set_features);
+  cls_register_cxx_method(h_class, "get_size",
+			  CLS_METHOD_RD,
+			  get_size, &h_get_size);
+  cls_register_cxx_method(h_class, "set_size",
+			  CLS_METHOD_RD | CLS_METHOD_WR,
+			  set_size, &h_set_size);
+  cls_register_cxx_method(h_class, "get_snapcontext",
+			  CLS_METHOD_RD,
+			  get_snapcontext, &h_get_snapcontext);
+  cls_register_cxx_method(h_class, "get_object_prefix",
+			  CLS_METHOD_RD,
+			  get_object_prefix, &h_get_object_prefix);
+  cls_register_cxx_method(h_class, "get_data_pool", CLS_METHOD_RD,
+                          get_data_pool, &h_get_data_pool);
+  cls_register_cxx_method(h_class, "get_snapshot_name",
+			  CLS_METHOD_RD,
+			  get_snapshot_name, &h_get_snapshot_name);
+  cls_register_cxx_method(h_class, "get_snapshot_timestamp",
+			  CLS_METHOD_RD,
+			  get_snapshot_timestamp, &h_get_snapshot_timestamp);
+  cls_register_cxx_method(h_class, "snapshot_get",
+                          CLS_METHOD_RD,
+                          snapshot_get, &h_snapshot_get);
+  cls_register_cxx_method(h_class, "snapshot_add",
+			  CLS_METHOD_RD | CLS_METHOD_WR,
+			  snapshot_add, &h_snapshot_add);
+  cls_register_cxx_method(h_class, "snapshot_remove",
+			  CLS_METHOD_RD | CLS_METHOD_WR,
+			  snapshot_remove, &h_snapshot_remove);
+  cls_register_cxx_method(h_class, "snapshot_rename",
+			  CLS_METHOD_RD | CLS_METHOD_WR,
+			  snapshot_rename, &h_snapshot_rename);
+  cls_register_cxx_method(h_class, "snapshot_trash_add",
+                          CLS_METHOD_RD | CLS_METHOD_WR,
+                          snapshot_trash_add, &h_snapshot_trash_add);
+  cls_register_cxx_method(h_class, "get_all_features",
+			  CLS_METHOD_RD,
+			  get_all_features, &h_get_all_features);
+
+  // NOTE: deprecate v1 parent APIs after mimic EOLed
+  cls_register_cxx_method(h_class, "get_parent",
+			  CLS_METHOD_RD,
+			  get_parent, &h_get_parent);
+  cls_register_cxx_method(h_class, "set_parent",
+			  CLS_METHOD_RD | CLS_METHOD_WR,
+			  set_parent, &h_set_parent);
+  cls_register_cxx_method(h_class, "remove_parent",
+			  CLS_METHOD_RD | CLS_METHOD_WR,
+			  remove_parent, &h_remove_parent);
+
+  cls_register_cxx_method(h_class, "parent_get",
+                          CLS_METHOD_RD, parent_get, &h_parent_get);
+  cls_register_cxx_method(h_class, "parent_overlap_get",
+                          CLS_METHOD_RD, parent_overlap_get,
+                          &h_parent_overlap_get);
+  cls_register_cxx_method(h_class, "parent_attach",
+                          CLS_METHOD_RD | CLS_METHOD_WR,
+                          parent_attach, &h_parent_attach);
+  cls_register_cxx_method(h_class, "parent_detach",
+                          CLS_METHOD_RD | CLS_METHOD_WR,
+                          parent_detach, &h_parent_detach);
+
+  cls_register_cxx_method(h_class, "set_protection_status",
+			  CLS_METHOD_RD | CLS_METHOD_WR,
+			  set_protection_status, &h_set_protection_status);
+  cls_register_cxx_method(h_class, "get_protection_status",
+			  CLS_METHOD_RD,
+			  get_protection_status, &h_get_protection_status);
+  cls_register_cxx_method(h_class, "get_stripe_unit_count",
+			  CLS_METHOD_RD,
+			  get_stripe_unit_count, &h_get_stripe_unit_count);
+  cls_register_cxx_method(h_class, "set_stripe_unit_count",
+			  CLS_METHOD_RD | CLS_METHOD_WR,
+			  set_stripe_unit_count, &h_set_stripe_unit_count);
+  cls_register_cxx_method(h_class, "get_create_timestamp",
+                          CLS_METHOD_RD,
+                          get_create_timestamp, &h_get_create_timestamp);
+  cls_register_cxx_method(h_class, "get_access_timestamp",
+                          CLS_METHOD_RD,
+                          get_access_timestamp, &h_get_access_timestamp);
+  cls_register_cxx_method(h_class, "get_modify_timestamp",
+                          CLS_METHOD_RD,
+                          get_modify_timestamp, &h_get_modify_timestamp);
+  cls_register_cxx_method(h_class, "get_flags",
+                          CLS_METHOD_RD,
+                          get_flags, &h_get_flags);
+  cls_register_cxx_method(h_class, "set_flags",
+                          CLS_METHOD_RD | CLS_METHOD_WR,
+                          set_flags, &h_set_flags);
+  cls_register_cxx_method(h_class, "op_features_get", CLS_METHOD_RD,
+                          op_features_get, &h_op_features_get);
+  cls_register_cxx_method(h_class, "op_features_set",
+                          CLS_METHOD_RD | CLS_METHOD_WR,
+                          op_features_set, &h_op_features_set);
+  cls_register_cxx_method(h_class, "metadata_list",
+                          CLS_METHOD_RD,
+			  metadata_list, &h_metadata_list);
+  cls_register_cxx_method(h_class, "metadata_set",
+                          CLS_METHOD_RD | CLS_METHOD_WR,
+			  metadata_set, &h_metadata_set);
+  cls_register_cxx_method(h_class, "metadata_remove",
+                          CLS_METHOD_RD | CLS_METHOD_WR,
+			  metadata_remove, &h_metadata_remove);
+  cls_register_cxx_method(h_class, "metadata_get",
+                          CLS_METHOD_RD,
+			  metadata_get, &h_metadata_get);
+  cls_register_cxx_method(h_class, "snapshot_get_limit",
+			  CLS_METHOD_RD,
+			  snapshot_get_limit, &h_snapshot_get_limit);
+  cls_register_cxx_method(h_class, "snapshot_set_limit",
+			  CLS_METHOD_RD | CLS_METHOD_WR,
+			  snapshot_set_limit, &h_snapshot_set_limit);
+  cls_register_cxx_method(h_class, "child_attach",
+                          CLS_METHOD_RD | CLS_METHOD_WR,
+                          child_attach, &h_child_attach);
+  cls_register_cxx_method(h_class, "child_detach",
+                          CLS_METHOD_RD | CLS_METHOD_WR,
+                          child_detach, &h_child_detach);
+  cls_register_cxx_method(h_class, "children_list",
+                          CLS_METHOD_RD,
+                          children_list, &h_children_list);
+  cls_register_cxx_method(h_class, "migration_set",
+                          CLS_METHOD_RD | CLS_METHOD_WR,
+                          migration_set, &h_migration_set);
+  cls_register_cxx_method(h_class, "migration_set_state",
+                          CLS_METHOD_RD | CLS_METHOD_WR,
+                          migration_set_state, &h_migration_set_state);
+  cls_register_cxx_method(h_class, "migration_get",
+                          CLS_METHOD_RD,
+                          migration_get, &h_migration_get);
+  cls_register_cxx_method(h_class, "migration_remove",
+                          CLS_METHOD_RD | CLS_METHOD_WR,
+                          migration_remove, &h_migration_remove);
+
+  cls_register_cxx_method(h_class, "set_modify_timestamp",
+	            	  CLS_METHOD_RD | CLS_METHOD_WR,
+                          set_modify_timestamp, &h_set_modify_timestamp);
+
+  cls_register_cxx_method(h_class, "set_access_timestamp",
+	            	  CLS_METHOD_RD | CLS_METHOD_WR,
+                          set_access_timestamp, &h_set_access_timestamp);
+
+  /* methods for the rbd_children object */
+  cls_register_cxx_method(h_class, "add_child",
+			  CLS_METHOD_RD | CLS_METHOD_WR,
+			  add_child, &h_add_child);
+  cls_register_cxx_method(h_class, "remove_child",
+			  CLS_METHOD_RD | CLS_METHOD_WR,
+			  remove_child, &h_remove_child);
+  cls_register_cxx_method(h_class, "get_children",
+			  CLS_METHOD_RD,
+			  get_children, &h_get_children);
+
+  /* methods for the rbd_id.$image_name objects */
+  cls_register_cxx_method(h_class, "get_id",
+			  CLS_METHOD_RD,
+			  get_id, &h_get_id);
+  cls_register_cxx_method(h_class, "set_id",
+			  CLS_METHOD_RD | CLS_METHOD_WR,
+			  set_id, &h_set_id);
+
+  /* methods for the rbd_directory object */
+  cls_register_cxx_method(h_class, "dir_get_id",
+			  CLS_METHOD_RD,
+			  dir_get_id, &h_dir_get_id);
+  cls_register_cxx_method(h_class, "dir_get_name",
+			  CLS_METHOD_RD,
+			  dir_get_name, &h_dir_get_name);
+  cls_register_cxx_method(h_class, "dir_list",
+			  CLS_METHOD_RD,
+			  dir_list, &h_dir_list);
+  cls_register_cxx_method(h_class, "dir_add_image",
+			  CLS_METHOD_RD | CLS_METHOD_WR,
+			  dir_add_image, &h_dir_add_image);
+  cls_register_cxx_method(h_class, "dir_remove_image",
+			  CLS_METHOD_RD | CLS_METHOD_WR,
+			  dir_remove_image, &h_dir_remove_image);
+  cls_register_cxx_method(h_class, "dir_rename_image",
+			  CLS_METHOD_RD | CLS_METHOD_WR,
+			  dir_rename_image, &h_dir_rename_image);
+  cls_register_cxx_method(h_class, "dir_state_assert", CLS_METHOD_RD,
+                          dir_state_assert, &h_dir_state_assert);
+  cls_register_cxx_method(h_class, "dir_state_set",
+			  CLS_METHOD_RD | CLS_METHOD_WR,
+                          dir_state_set, &h_dir_state_set);
+
+  /* methods for the rbd_object_map.$image_id object */
+  cls_register_cxx_method(h_class, "object_map_load",
+                          CLS_METHOD_RD,
+			  object_map_load, &h_object_map_load);
+  cls_register_cxx_method(h_class, "object_map_save",
+                          CLS_METHOD_RD | CLS_METHOD_WR,
+			  object_map_save, &h_object_map_save);
+  cls_register_cxx_method(h_class, "object_map_resize",
+                          CLS_METHOD_RD | CLS_METHOD_WR,
+			  object_map_resize, &h_object_map_resize);
+  cls_register_cxx_method(h_class, "object_map_update",
+                          CLS_METHOD_RD | CLS_METHOD_WR,
+			  object_map_update, &h_object_map_update);
+  cls_register_cxx_method(h_class, "object_map_snap_add",
+                          CLS_METHOD_RD | CLS_METHOD_WR,
+			  object_map_snap_add, &h_object_map_snap_add);
+  cls_register_cxx_method(h_class, "object_map_snap_remove",
+                          CLS_METHOD_RD | CLS_METHOD_WR,
+			  object_map_snap_remove, &h_object_map_snap_remove);
+
+ /* methods for the old format */
+  cls_register_cxx_method(h_class, "snap_list",
+			  CLS_METHOD_RD,
+			  old_snapshots_list, &h_old_snapshots_list);
+  cls_register_cxx_method(h_class, "snap_add",
+			  CLS_METHOD_RD | CLS_METHOD_WR,
+			  old_snapshot_add, &h_old_snapshot_add);
+  cls_register_cxx_method(h_class, "snap_remove",
+			  CLS_METHOD_RD | CLS_METHOD_WR,
+			  old_snapshot_remove, &h_old_snapshot_remove);
+  cls_register_cxx_method(h_class, "snap_rename",
+			  CLS_METHOD_RD | CLS_METHOD_WR,
+			  old_snapshot_rename, &h_old_snapshot_rename);
+
+  /* methods for the rbd_mirroring object */
+  cls_register_cxx_method(h_class, "mirror_uuid_get", CLS_METHOD_RD,
+                          mirror_uuid_get, &h_mirror_uuid_get);
+  cls_register_cxx_method(h_class, "mirror_uuid_set",
+                          CLS_METHOD_RD | CLS_METHOD_WR,
+                          mirror_uuid_set, &h_mirror_uuid_set);
+  cls_register_cxx_method(h_class, "mirror_mode_get", CLS_METHOD_RD,
+                          mirror_mode_get, &h_mirror_mode_get);
+  cls_register_cxx_method(h_class, "mirror_mode_set",
+                          CLS_METHOD_RD | CLS_METHOD_WR,
+                          mirror_mode_set, &h_mirror_mode_set);
+  cls_register_cxx_method(h_class, "mirror_peer_ping",
+                          CLS_METHOD_RD | CLS_METHOD_WR,
+                          mirror_peer_ping, &h_mirror_peer_ping);
+  cls_register_cxx_method(h_class, "mirror_peer_list", CLS_METHOD_RD,
+                          mirror_peer_list, &h_mirror_peer_list);
+  cls_register_cxx_method(h_class, "mirror_peer_add",
+                          CLS_METHOD_RD | CLS_METHOD_WR,
+                          mirror_peer_add, &h_mirror_peer_add);
+  cls_register_cxx_method(h_class, "mirror_peer_remove",
+                          CLS_METHOD_RD | CLS_METHOD_WR,
+                          mirror_peer_remove, &h_mirror_peer_remove);
+  cls_register_cxx_method(h_class, "mirror_peer_set_client",
+                          CLS_METHOD_RD | CLS_METHOD_WR,
+                          mirror_peer_set_client, &h_mirror_peer_set_client);
+  cls_register_cxx_method(h_class, "mirror_peer_set_cluster",
+                          CLS_METHOD_RD | CLS_METHOD_WR,
+                          mirror_peer_set_cluster, &h_mirror_peer_set_cluster);
+  cls_register_cxx_method(h_class, "mirror_peer_set_direction",
+                          CLS_METHOD_RD | CLS_METHOD_WR,
+                          mirror_peer_set_direction,
+                          &h_mirror_peer_set_direction);
+  cls_register_cxx_method(h_class, "mirror_image_list", CLS_METHOD_RD,
+                          mirror_image_list, &h_mirror_image_list);
+  cls_register_cxx_method(h_class, "mirror_image_get_image_id", CLS_METHOD_RD,
+                          mirror_image_get_image_id,
+                          &h_mirror_image_get_image_id);
+  cls_register_cxx_method(h_class, "mirror_image_get", CLS_METHOD_RD,
+                          mirror_image_get, &h_mirror_image_get);
+  cls_register_cxx_method(h_class, "mirror_image_set",
+                          CLS_METHOD_RD | CLS_METHOD_WR,
+                          mirror_image_set, &h_mirror_image_set);
+  cls_register_cxx_method(h_class, "mirror_image_remove",
+                          CLS_METHOD_RD | CLS_METHOD_WR,
+                          mirror_image_remove, &h_mirror_image_remove);
+  cls_register_cxx_method(h_class, "mirror_image_status_set",
+                          CLS_METHOD_RD | CLS_METHOD_WR | CLS_METHOD_PROMOTE,
+                          mirror_image_status_set, &h_mirror_image_status_set);
+  cls_register_cxx_method(h_class, "mirror_image_status_remove",
+                          CLS_METHOD_RD | CLS_METHOD_WR,
+                          mirror_image_status_remove,
+			  &h_mirror_image_status_remove);
+  cls_register_cxx_method(h_class, "mirror_image_status_get", CLS_METHOD_RD,
+                          mirror_image_status_get, &h_mirror_image_status_get);
+  cls_register_cxx_method(h_class, "mirror_image_status_list", CLS_METHOD_RD,
+                          mirror_image_status_list,
+			  &h_mirror_image_status_list);
+  cls_register_cxx_method(h_class, "mirror_image_status_get_summary",
+			  CLS_METHOD_RD, mirror_image_status_get_summary,
+			  &h_mirror_image_status_get_summary);
+  cls_register_cxx_method(h_class, "mirror_image_status_remove_down",
+                          CLS_METHOD_RD | CLS_METHOD_WR,
+                          mirror_image_status_remove_down,
+			  &h_mirror_image_status_remove_down);
+  cls_register_cxx_method(h_class, "mirror_image_instance_get", CLS_METHOD_RD,
+                          mirror_image_instance_get,
+                          &h_mirror_image_instance_get);
+  cls_register_cxx_method(h_class, "mirror_image_instance_list", CLS_METHOD_RD,
+                          mirror_image_instance_list,
+                          &h_mirror_image_instance_list);
+  cls_register_cxx_method(h_class, "mirror_instances_list", CLS_METHOD_RD,
+                          mirror_instances_list, &h_mirror_instances_list);
+  cls_register_cxx_method(h_class, "mirror_instances_add",
+                          CLS_METHOD_RD | CLS_METHOD_WR | CLS_METHOD_PROMOTE,
+                          mirror_instances_add, &h_mirror_instances_add);
+  cls_register_cxx_method(h_class, "mirror_instances_remove",
+                          CLS_METHOD_RD | CLS_METHOD_WR,
+                          mirror_instances_remove,
+                          &h_mirror_instances_remove);
+  cls_register_cxx_method(h_class, "mirror_image_map_list",
+                          CLS_METHOD_RD, mirror_image_map_list,
+                          &h_mirror_image_map_list);
+  cls_register_cxx_method(h_class, "mirror_image_map_update",
+                          CLS_METHOD_WR, mirror_image_map_update,
+                          &h_mirror_image_map_update);
+  cls_register_cxx_method(h_class, "mirror_image_map_remove",
+                          CLS_METHOD_WR, mirror_image_map_remove,
+                          &h_mirror_image_map_remove);
+  cls_register_cxx_method(h_class, "mirror_image_snapshot_unlink_peer",
+                          CLS_METHOD_RD | CLS_METHOD_WR,
+                          mirror_image_snapshot_unlink_peer,
+                          &h_mirror_image_snapshot_unlink_peer);
+  cls_register_cxx_method(h_class, "mirror_image_snapshot_set_copy_progress",
+                          CLS_METHOD_RD | CLS_METHOD_WR,
+                          mirror_image_snapshot_set_copy_progress,
+                          &h_mirror_image_snapshot_set_copy_progress);
+
+  /* methods for the groups feature */
+  cls_register_cxx_method(h_class, "group_dir_list",
+			  CLS_METHOD_RD,
+			  group_dir_list, &h_group_dir_list);
+  cls_register_cxx_method(h_class, "group_dir_add",
+			  CLS_METHOD_RD | CLS_METHOD_WR,
+			  group_dir_add, &h_group_dir_add);
+  cls_register_cxx_method(h_class, "group_dir_remove",
+			  CLS_METHOD_RD | CLS_METHOD_WR,
+			  group_dir_remove, &h_group_dir_remove);
+  cls_register_cxx_method(h_class, "group_dir_rename",
+                          CLS_METHOD_RD | CLS_METHOD_WR,
+                          group_dir_rename, &h_group_dir_rename);
+  cls_register_cxx_method(h_class, "group_image_remove",
+			  CLS_METHOD_RD | CLS_METHOD_WR,
+			  group_image_remove, &h_group_image_remove);
+  cls_register_cxx_method(h_class, "group_image_list",
+			  CLS_METHOD_RD,
+			  group_image_list, &h_group_image_list);
+  cls_register_cxx_method(h_class, "group_image_set",
+			  CLS_METHOD_RD | CLS_METHOD_WR,
+			  group_image_set, &h_group_image_set);
+  cls_register_cxx_method(h_class, "image_group_add",
+			  CLS_METHOD_RD | CLS_METHOD_WR,
+			  image_group_add, &h_image_group_add);
+  cls_register_cxx_method(h_class, "image_group_remove",
+			  CLS_METHOD_RD | CLS_METHOD_WR,
+			  image_group_remove, &h_image_group_remove);
+  cls_register_cxx_method(h_class, "image_group_get",
+			  CLS_METHOD_RD,
+			  image_group_get, &h_image_group_get);
+  cls_register_cxx_method(h_class, "group_snap_set",
+			  CLS_METHOD_RD | CLS_METHOD_WR,
+			  group_snap_set, &h_group_snap_set);
+  cls_register_cxx_method(h_class, "group_snap_remove",
+			  CLS_METHOD_RD | CLS_METHOD_WR,
+			  group_snap_remove, &h_group_snap_remove);
+  cls_register_cxx_method(h_class, "group_snap_get_by_id",
+			  CLS_METHOD_RD,
+			  group_snap_get_by_id, &h_group_snap_get_by_id);
+  cls_register_cxx_method(h_class, "group_snap_list",
+			  CLS_METHOD_RD,
+			  group_snap_list, &h_group_snap_list);
+
+  /* rbd_trash object methods */
+  cls_register_cxx_method(h_class, "trash_add",
+                          CLS_METHOD_RD | CLS_METHOD_WR,
+                          trash_add, &h_trash_add);
+  cls_register_cxx_method(h_class, "trash_remove",
+                          CLS_METHOD_RD | CLS_METHOD_WR,
+                          trash_remove, &h_trash_remove);
+  cls_register_cxx_method(h_class, "trash_list",
+                          CLS_METHOD_RD,
+                          trash_list, &h_trash_list);
+  cls_register_cxx_method(h_class, "trash_get",
+                          CLS_METHOD_RD,
+                          trash_get, &h_trash_get);
+  cls_register_cxx_method(h_class, "trash_state_set",
+                          CLS_METHOD_RD | CLS_METHOD_WR,
+                          trash_state_set, &h_trash_state_set);
+
+  /* rbd_namespace object methods */
+  cls_register_cxx_method(h_class, "namespace_add",
+                          CLS_METHOD_RD | CLS_METHOD_WR,
+                          namespace_add, &h_namespace_add);
+  cls_register_cxx_method(h_class, "namespace_remove",
+                          CLS_METHOD_RD | CLS_METHOD_WR,
+                          namespace_remove, &h_namespace_remove);
+  cls_register_cxx_method(h_class, "namespace_list", CLS_METHOD_RD,
+                          namespace_list, &h_namespace_list);
+
+  /* data object methods */
+  cls_register_cxx_method(h_class, "copyup",
+			  CLS_METHOD_RD | CLS_METHOD_WR,
+			  copyup, &h_copyup);
+  cls_register_cxx_method(h_class, "sparse_copyup",
+			  CLS_METHOD_RD | CLS_METHOD_WR,
+			  sparse_copyup, &h_sparse_copyup);
+  cls_register_cxx_method(h_class, "assert_snapc_seq",
+                          CLS_METHOD_RD | CLS_METHOD_WR,
+                          assert_snapc_seq,
+                          &h_assert_snapc_seq);
+  cls_register_cxx_method(h_class, "sparsify",
+			  CLS_METHOD_RD | CLS_METHOD_WR,
+			  sparsify, &h_sparsify);
+}
diff --git a/src/cls/rbd/cls_rbd.h b/src/cls/rbd/cls_rbd.h
new file mode 100644
index 000000000..566bcdf6c
--- /dev/null
+++ b/src/cls/rbd/cls_rbd.h
@@ -0,0 +1,243 @@
+// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
+// vim: ts=8 sw=2 smarttab
+
+#ifndef __CEPH_CLS_RBD_H
+#define __CEPH_CLS_RBD_H
+
+#include "include/types.h"
+#include "include/buffer_fwd.h"
+#include "include/rbd_types.h"
+#include "common/Formatter.h"
+#include "cls/rbd/cls_rbd_types.h"
+
+/// information about our parent image, if any
+struct cls_rbd_parent {
+  int64_t pool_id = -1;
+  std::string pool_namespace;
+  std::string image_id;
+  snapid_t snap_id = CEPH_NOSNAP;
+  std::optional<uint64_t> head_overlap = std::nullopt;
+
+  cls_rbd_parent() {
+  }
+  cls_rbd_parent(const cls::rbd::ParentImageSpec& parent_image_spec,
+                 const std::optional<uint64_t>& head_overlap)
+    : pool_id(parent_image_spec.pool_id),
+      pool_namespace(parent_image_spec.pool_namespace),
+      image_id(parent_image_spec.image_id), snap_id(parent_image_spec.snap_id),
+      head_overlap(head_overlap) {
+  }
+
+  inline bool exists() const {
+    return (pool_id >= 0 && !image_id.empty() && snap_id != CEPH_NOSNAP);
+  }
+
+  inline bool operator==(const cls_rbd_parent& rhs) const {
+    return (pool_id == rhs.pool_id &&
+            pool_namespace == rhs.pool_namespace &&
+            image_id == rhs.image_id &&
+            snap_id == rhs.snap_id);
+  }
+  inline bool operator!=(const cls_rbd_parent& rhs) const {
+    return !(*this == rhs);
+  }
+
+  void encode(ceph::buffer::list& bl, uint64_t features) const {
+    // NOTE: remove support for version 1 after Nautilus EOLed
+    uint8_t version = 1;
+    if ((features & CEPH_FEATURE_SERVER_NAUTILUS) != 0ULL) {
+      // break backwards compatability when using nautilus or later OSDs
+      version = 2;
+    }
+
+    ENCODE_START(version, version, bl);
+    encode(pool_id, bl);
+    if (version >= 2) {
+      encode(pool_namespace, bl);
+    }
+    encode(image_id, bl);
+    encode(snap_id, bl);
+    if (version == 1) {
+      encode(head_overlap.value_or(0ULL), bl);
+    } else {
+      encode(head_overlap, bl);
+    }
+    ENCODE_FINISH(bl);
+  }
+
+  void decode(ceph::buffer::list::const_iterator& bl) {
+    DECODE_START(2, bl);
+    decode(pool_id, bl);
+    if (struct_v >= 2) {
+      decode(pool_namespace, bl);
+    }
+    decode(image_id, bl);
+    decode(snap_id, bl);
+    if (struct_v == 1) {
+      uint64_t overlap;
+      decode(overlap, bl);
+      head_overlap = overlap;
+    } else {
+      decode(head_overlap, bl);
+    }
+    DECODE_FINISH(bl);
+  }
+
+  void dump(ceph::Formatter *f) const {
+    f->dump_int("pool_id", pool_id);
+    f->dump_string("pool_namespace", pool_namespace);
+    f->dump_string("image_id", image_id);
+    f->dump_unsigned("snap_id", snap_id);
+    if (head_overlap) {
+      f->dump_unsigned("head_overlap", *head_overlap);
+    }
+  }
+
+  static void generate_test_instances(std::list<cls_rbd_parent*>& o) {
+    o.push_back(new cls_rbd_parent{});
+    o.push_back(new cls_rbd_parent{{1, "", "image id", 234}, {}});
+    o.push_back(new cls_rbd_parent{{1, "", "image id", 234}, {123}});
+    o.push_back(new cls_rbd_parent{{1, "ns", "image id", 234}, {123}});
+  }
+};
+WRITE_CLASS_ENCODER_FEATURES(cls_rbd_parent)
+
+struct cls_rbd_snap {
+  snapid_t id = CEPH_NOSNAP;
+  std::string name;
+  uint64_t image_size = 0;
+  uint8_t protection_status = RBD_PROTECTION_STATUS_UNPROTECTED;
+  cls_rbd_parent parent;
+  uint64_t flags = 0;
+  utime_t timestamp;
+  cls::rbd::SnapshotNamespace snapshot_namespace = {
+    cls::rbd::UserSnapshotNamespace{}};
+  uint32_t child_count = 0;
+  std::optional<uint64_t> parent_overlap = std::nullopt;
+
+  cls_rbd_snap() {
+  }
+  cls_rbd_snap(snapid_t id, const std::string& name, uint64_t image_size,
+               uint8_t protection_status, const cls_rbd_parent& parent,
+               uint64_t flags, utime_t timestamp,
+               const cls::rbd::SnapshotNamespace& snapshot_namespace,
+               uint32_t child_count,
+               const std::optional<uint64_t>& parent_overlap)
+    : id(id), name(name), image_size(image_size),
+      protection_status(protection_status), parent(parent), flags(flags),
+      timestamp(timestamp), snapshot_namespace(snapshot_namespace),
+      child_count(child_count), parent_overlap(parent_overlap) {
+  }
+
+  bool migrate_parent_format(uint64_t features) const {
+    return (((features & CEPH_FEATURE_SERVER_NAUTILUS) != 0) &&
+            (parent.exists()));
+  }
+
+  void encode(ceph::buffer::list& bl, uint64_t features) const {
+    // NOTE: remove support for versions < 8 after Nautilus EOLed
+    uint8_t min_version = 1;
+    if ((features & CEPH_FEATURE_SERVER_NAUTILUS) != 0ULL) {
+      // break backwards compatability when using nautilus or later OSDs
+      min_version = 8;
+    }
+
+    ENCODE_START(8, min_version, bl);
+    encode(id, bl);
+    encode(name, bl);
+    encode(image_size, bl);
+    if (min_version < 8) {
+      uint64_t image_features = 0;
+      encode(image_features, bl); // unused -- preserve ABI
+      encode(parent, bl, features);
+    }
+    encode(protection_status, bl);
+    encode(flags, bl);
+    encode(snapshot_namespace, bl);
+    encode(timestamp, bl);
+    encode(child_count, bl);
+    encode(parent_overlap, bl);
+    ENCODE_FINISH(bl);
+  }
+
+  void decode(ceph::buffer::list::const_iterator& p) {
+    DECODE_START(8, p);
+    decode(id, p);
+    decode(name, p);
+    decode(image_size, p);
+    if (struct_compat < 8) {
+      uint64_t features;
+      decode(features, p); // unused -- preserve ABI
+    }
+    if (struct_v >= 2 && struct_compat < 8) {
+      decode(parent, p);
+    }
+    if (struct_v >= 3) {
+      decode(protection_status, p);
+    }
+    if (struct_v >= 4) {
+      decode(flags, p);
+    }
+    if (struct_v >= 5) {
+      decode(snapshot_namespace, p);
+    }
+    if (struct_v >= 6) {
+      decode(timestamp, p);
+    }
+    if (struct_v >= 7) {
+      decode(child_count, p);
+    }
+    if (struct_v >= 8) {
+      decode(parent_overlap, p);
+    }
+    DECODE_FINISH(p);
+  }
+
+  void dump(ceph::Formatter *f) const {
+    f->dump_unsigned("id", id);
+    f->dump_string("name", name);
+    f->dump_unsigned("image_size", image_size);
+    if (parent.exists()) {
+      f->open_object_section("parent");
+      parent.dump(f);
+      f->close_section();
+    }
+    switch (protection_status) {
+    case RBD_PROTECTION_STATUS_UNPROTECTED:
+      f->dump_string("protection_status", "unprotected");
+      break;
+    case RBD_PROTECTION_STATUS_UNPROTECTING:
+      f->dump_string("protection_status", "unprotecting");
+      break;
+    case RBD_PROTECTION_STATUS_PROTECTED:
+      f->dump_string("protection_status", "protected");
+      break;
+    default:
+      ceph_abort();
+    }
+    f->dump_unsigned("child_count", child_count);
+    if (parent_overlap) {
+      f->dump_unsigned("parent_overlap", *parent_overlap);
+    }
+  }
+
+  static void generate_test_instances(std::list<cls_rbd_snap*>& o) {
+    o.push_back(new cls_rbd_snap{});
+    o.push_back(new cls_rbd_snap{1, "snap", 123456,
+                                 RBD_PROTECTION_STATUS_PROTECTED,
+                                 {{1, "", "image", 123}, 234}, 31, {},
+                                 cls::rbd::UserSnapshotNamespace{}, 543, {}});
+    o.push_back(new cls_rbd_snap{1, "snap", 123456,
+                                 RBD_PROTECTION_STATUS_PROTECTED,
+                                 {{1, "", "image", 123}, 234}, 31, {},
+                                 cls::rbd::UserSnapshotNamespace{}, 543, {0}});
+    o.push_back(new cls_rbd_snap{1, "snap", 123456,
+                                 RBD_PROTECTION_STATUS_PROTECTED,
+                                 {{1, "ns", "image", 123}, 234}, 31, {},
+                                 cls::rbd::UserSnapshotNamespace{}, 543,
+                                 {123}});
+  }
+};
+WRITE_CLASS_ENCODER_FEATURES(cls_rbd_snap)
+
+#endif // __CEPH_CLS_RBD_H
diff --git a/src/cls/rbd/cls_rbd_client.cc b/src/cls/rbd/cls_rbd_client.cc
new file mode 100644
index 000000000..535de35ef
--- /dev/null
+++ b/src/cls/rbd/cls_rbd_client.cc
@@ -0,0 +1,3010 @@
+// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
+// vim: ts=8 sw=2 smarttab
+
+#include "cls/rbd/cls_rbd_client.h"
+#include "cls/lock/cls_lock_client.h"
+#include "include/buffer.h"
+#include "include/encoding.h"
+#include "include/rbd_types.h"
+#include "include/rados/librados.hpp"
+#include "include/neorados/RADOS.hpp"
+#include "common/bit_vector.hpp"
+
+#include <errno.h>
+
+namespace librbd {
+namespace cls_client {
+
+using std::map;
+using std::set;
+using std::string;
+
+using ceph::bufferlist;
+using ceph::decode;
+using ceph::encode;
+
+void create_image(librados::ObjectWriteOperation *op, uint64_t size,
+                  uint8_t order, uint64_t features,
+                  const std::string &object_prefix, int64_t data_pool_id)
+{
+  bufferlist bl;
+  encode(size, bl);
+  encode(order, bl);
+  encode(features, bl);
+  encode(object_prefix, bl);
+  encode(data_pool_id, bl);
+
+  op->exec("rbd", "create", bl);
+}
+
+int create_image(librados::IoCtx *ioctx, const std::string &oid,
+                 uint64_t size, uint8_t order, uint64_t features,
+                 const std::string &object_prefix, int64_t data_pool_id)
+{
+  librados::ObjectWriteOperation op;
+  create_image(&op, size, order, features, object_prefix, data_pool_id);
+
+  return ioctx->operate(oid, &op);
+}
+
+void get_features_start(librados::ObjectReadOperation *op, bool read_only)
+{
+  bufferlist bl;
+  encode(static_cast<uint64_t>(CEPH_NOSNAP), bl);
+  encode(read_only, bl);
+  op->exec("rbd", "get_features", bl);
+}
+
+int get_features_finish(bufferlist::const_iterator *it, uint64_t *features,
+                        uint64_t *incompatible_features)
+{
+  try {
+    decode(*features, *it);
+    decode(*incompatible_features, *it);
+  } catch (const ceph::buffer::error &err) {
+    return -EBADMSG;
+  }
+
+  return 0;
+}
+
+int get_features(librados::IoCtx *ioctx, const std::string &oid,
+                 bool read_only, uint64_t *features,
+                 uint64_t *incompatible_features)
+{
+  librados::ObjectReadOperation op;
+  get_features_start(&op, read_only);
+
+  bufferlist out_bl;
+  int r = ioctx->operate(oid, &op, &out_bl);
+  if (r < 0) {
+    return r;
+  }
+
+  auto it = out_bl.cbegin();
+  return get_features_finish(&it, features, incompatible_features);
+}
+
+void set_features(librados::ObjectWriteOperation *op, uint64_t features,
+                  uint64_t mask)
+{
+  bufferlist bl;
+  encode(features, bl);
+  encode(mask, bl);
+
+  op->exec("rbd", "set_features", bl);
+}
+
+int set_features(librados::IoCtx *ioctx, const std::string &oid,
+                  uint64_t features, uint64_t mask)
+{
+  librados::ObjectWriteOperation op;
+  set_features(&op, features, mask);
+
+  return ioctx->operate(oid, &op);
+}
+
+void get_object_prefix_start(librados::ObjectReadOperation *op)
+{
+  bufferlist bl;
+  op->exec("rbd", "get_object_prefix", bl);
+}
+
+int get_object_prefix_finish(bufferlist::const_iterator *it,
+                             std::string *object_prefix)
+{
+  try {
+    decode(*object_prefix, *it);
+  } catch (const ceph::buffer::error &err) {
+    return -EBADMSG;
+  }
+  return 0;
+}
+
+int get_object_prefix(librados::IoCtx *ioctx, const std::string &oid,
+                      std::string *object_prefix)
+{
+  librados::ObjectReadOperation op;
+  get_object_prefix_start(&op);
+
+  bufferlist out_bl;
+  int r = ioctx->operate(oid, &op, &out_bl);
+  if (r < 0) {
+    return r;
+  }
+
+  auto it = out_bl.cbegin();
+  return get_object_prefix_finish(&it, object_prefix);
+}
+
+void get_data_pool_start(librados::ObjectReadOperation *op) {
+  bufferlist bl;
+  op->exec("rbd", "get_data_pool", bl);
+}
+
+int get_data_pool_finish(bufferlist::const_iterator *it, int64_t *data_pool_id) {
+  try {
+    decode(*data_pool_id, *it);
+  } catch (const ceph::buffer::error &err) {
+    return -EBADMSG;
+  }
+  return 0;
+}
+
+int get_data_pool(librados::IoCtx *ioctx, const std::string &oid,
+                  int64_t *data_pool_id) {
+  librados::ObjectReadOperation op;
+  get_data_pool_start(&op);
+
+  bufferlist out_bl;
+  int r = ioctx->operate(oid, &op, &out_bl);
+  if (r < 0) {
+    return r;
+  }
+
+  auto it = out_bl.cbegin();
+  return get_data_pool_finish(&it, data_pool_id);
+}
+
+void get_size_start(librados::ObjectReadOperation *op, snapid_t snap_id)
+{
+  bufferlist bl;
+  encode(snap_id, bl);
+  op->exec("rbd", "get_size", bl);
+}
+
+int get_size_finish(bufferlist::const_iterator *it, uint64_t *size,
+                    uint8_t *order)
+{
+  try {
+    decode(*order, *it);
+    decode(*size, *it);
+  } catch (const ceph::buffer::error &err) {
+    return -EBADMSG;
+  }
+  return 0;
+}
+
+int get_size(librados::IoCtx *ioctx, const std::string &oid,
+             snapid_t snap_id, uint64_t *size, uint8_t *order)
+{
+  librados::ObjectReadOperation op;
+  get_size_start(&op, snap_id);
+
+  bufferlist out_bl;
+  int r = ioctx->operate(oid, &op, &out_bl);
+  if (r < 0) {
+    return r;
+  }
+
+  auto it = out_bl.cbegin();
+  return get_size_finish(&it, size, order);
+}
+
+int set_size(librados::IoCtx *ioctx, const std::string &oid,
+             uint64_t size)
+{
+  librados::ObjectWriteOperation op;
+  set_size(&op, size);
+  return ioctx->operate(oid, &op);
+}
+
+void set_size(librados::ObjectWriteOperation *op, uint64_t size)
+{
+  bufferlist bl;
+  encode(size, bl);
+  op->exec("rbd", "set_size", bl);
+}
+
+void get_flags_start(librados::ObjectReadOperation *op, snapid_t snap_id) {
+  bufferlist in_bl;
+  encode(static_cast<snapid_t>(snap_id), in_bl);
+  op->exec("rbd", "get_flags", in_bl);
+}
+
+int get_flags_finish(bufferlist::const_iterator *it, uint64_t *flags) {
+  try {
+    decode(*flags, *it);
+  } catch (const ceph::buffer::error &err) {
+    return -EBADMSG;
+  }
+  return 0;
+}
+
+int get_flags(librados::IoCtx *ioctx, const std::string &oid,
+              snapid_t snap_id, uint64_t *flags)
+{
+  librados::ObjectReadOperation op;
+  get_flags_start(&op, snap_id);
+
+  bufferlist out_bl;
+  int r = ioctx->operate(oid, &op, &out_bl);
+  if (r < 0) {
+    return r;
+  }
+
+  auto it = out_bl.cbegin();
+  return get_flags_finish(&it, flags);
+}
+
+void set_flags(librados::ObjectWriteOperation *op, snapid_t snap_id,
+               uint64_t flags, uint64_t mask)
+{
+  bufferlist inbl;
+  encode(flags, inbl);
+  encode(mask, inbl);
+  encode(snap_id, inbl);
+  op->exec("rbd", "set_flags", inbl);
+}
+
+void op_features_get_start(librados::ObjectReadOperation *op)
+{
+  bufferlist in_bl;
+  op->exec("rbd", "op_features_get", in_bl);
+}
+
+int op_features_get_finish(bufferlist::const_iterator *it, uint64_t *op_features)
+{
+  try {
+    decode(*op_features, *it);
+  } catch (const ceph::buffer::error &err) {
+    return -EBADMSG;
+  }
+  return 0;
+}
+
+int op_features_get(librados::IoCtx *ioctx, const std::string &oid,
+                    uint64_t *op_features)
+{
+  librados::ObjectReadOperation op;
+  op_features_get_start(&op);
+
+  bufferlist out_bl;
+  int r = ioctx->operate(oid, &op, &out_bl);
+  if (r < 0) {
+    return r;
+  }
+
+  auto it = out_bl.cbegin();
+  return op_features_get_finish(&it, op_features);
+}
+
+void op_features_set(librados::ObjectWriteOperation *op,
+                     uint64_t op_features, uint64_t mask)
+{
+  bufferlist inbl;
+  encode(op_features, inbl);
+  encode(mask, inbl);
+  op->exec("rbd", "op_features_set", inbl);
+}
+
+int op_features_set(librados::IoCtx *ioctx, const std::string &oid,
+                    uint64_t op_features, uint64_t mask)
+{
+  librados::ObjectWriteOperation op;
+  op_features_set(&op, op_features, mask);
+
+  return ioctx->operate(oid, &op);
+}
+
+void get_parent_start(librados::ObjectReadOperation *op, snapid_t snap_id)
+{
+  bufferlist bl;
+  encode(snap_id, bl);
+  op->exec("rbd", "get_parent", bl);
+}
+
+int get_parent_finish(bufferlist::const_iterator *it,
+                      cls::rbd::ParentImageSpec *pspec,
+                      uint64_t *parent_overlap)
+{
+  *pspec = {};
+  try {
+    decode(pspec->pool_id, *it);
+    decode(pspec->image_id, *it);
+    decode(pspec->snap_id, *it);
+    decode(*parent_overlap, *it);
+  } catch (const ceph::buffer::error &) {
+    return -EBADMSG;
+  }
+  return 0;
+}
+
+int get_parent(librados::IoCtx *ioctx, const std::string &oid,
+               snapid_t snap_id, cls::rbd::ParentImageSpec *pspec,
+               uint64_t *parent_overlap)
+{
+  librados::ObjectReadOperation op;
+  get_parent_start(&op, snap_id);
+
+  bufferlist out_bl;
+  int r = ioctx->operate(oid, &op, &out_bl);
+  if (r < 0) {
+    return r;
+  }
+
+  auto it = out_bl.cbegin();
+  return get_parent_finish(&it, pspec, parent_overlap);
+}
+
+int set_parent(librados::IoCtx *ioctx, const std::string &oid,
+               const cls::rbd::ParentImageSpec &pspec, uint64_t parent_overlap)
+{
+  librados::ObjectWriteOperation op;
+  set_parent(&op, pspec, parent_overlap);
+  return ioctx->operate(oid, &op);
+}
+
+void set_parent(librados::ObjectWriteOperation *op,
+                const cls::rbd::ParentImageSpec &pspec,
+                uint64_t parent_overlap) {
+  assert(pspec.pool_namespace.empty());
+
+  bufferlist in_bl;
+  encode(pspec.pool_id, in_bl);
+  encode(pspec.image_id, in_bl);
+  encode(pspec.snap_id, in_bl);
+  encode(parent_overlap, in_bl);
+
+  op->exec("rbd", "set_parent", in_bl);
+}
+
+int remove_parent(librados::IoCtx *ioctx, const std::string &oid)
+{
+  librados::ObjectWriteOperation op;
+  remove_parent(&op);
+  return ioctx->operate(oid, &op);
+}
+
+void remove_parent(librados::ObjectWriteOperation *op)
+{
+  bufferlist inbl;
+  op->exec("rbd", "remove_parent", inbl);
+}
+
+void parent_get_start(librados::ObjectReadOperation* op) {
+  bufferlist in_bl;
+  op->exec("rbd", "parent_get", in_bl);
+}
+
+int parent_get_finish(bufferlist::const_iterator* it,
+                      cls::rbd::ParentImageSpec* parent_image_spec) {
+  try {
+    decode(*parent_image_spec, *it);
+  } catch (const ceph::buffer::error &) {
+    return -EBADMSG;
+  }
+  return 0;
+}
+
+int parent_get(librados::IoCtx* ioctx, const std::string &oid,
+               cls::rbd::ParentImageSpec* parent_image_spec) {
+  librados::ObjectReadOperation op;
+  parent_get_start(&op);
+
+  bufferlist out_bl;
+  int r = ioctx->operate(oid, &op, &out_bl);
+  if (r < 0) {
+    return r;
+  }
+
+  auto it = out_bl.cbegin();
+  r = parent_get_finish(&it, parent_image_spec);
+  if (r < 0) {
+    return r;
+  }
+  return 0;
+}
+
+void parent_overlap_get_start(librados::ObjectReadOperation* op,
+                              snapid_t snap_id) {
+  bufferlist in_bl;
+  encode(snap_id, in_bl);
+  op->exec("rbd", "parent_overlap_get", in_bl);
+}
+
+int parent_overlap_get_finish(bufferlist::const_iterator* it,
+                              std::optional<uint64_t>* parent_overlap) {
+  try {
+    decode(*parent_overlap, *it);
+  } catch (const ceph::buffer::error &) {
+    return -EBADMSG;
+  }
+  return 0;
+}
+
+int parent_overlap_get(librados::IoCtx* ioctx, const std::string &oid,
+                       snapid_t snap_id,
+                       std::optional<uint64_t>* parent_overlap) {
+  librados::ObjectReadOperation op;
+  parent_overlap_get_start(&op, snap_id);
+
+  bufferlist out_bl;
+  int r = ioctx->operate(oid, &op, &out_bl);
+  if (r < 0) {
+    return r;
+  }
+
+  auto it = out_bl.cbegin();
+  r = parent_overlap_get_finish(&it, parent_overlap);
+  if (r < 0) {
+    return r;
+  }
+  return 0;
+}
+
+void parent_attach(librados::ObjectWriteOperation* op,
+                   const cls::rbd::ParentImageSpec& parent_image_spec,
+                   uint64_t parent_overlap, bool reattach) {
+  bufferlist in_bl;
+  encode(parent_image_spec, in_bl);
+  encode(parent_overlap, in_bl);
+  encode(reattach, in_bl);
+  op->exec("rbd", "parent_attach", in_bl);
+}
+
+int parent_attach(librados::IoCtx *ioctx, const std::string &oid,
+                  const cls::rbd::ParentImageSpec& parent_image_spec,
+                  uint64_t parent_overlap, bool reattach) {
+  librados::ObjectWriteOperation op;
+  parent_attach(&op, parent_image_spec, parent_overlap, reattach);
+  return ioctx->operate(oid, &op);
+}
+
+void parent_detach(librados::ObjectWriteOperation* op) {
+  bufferlist in_bl;
+  op->exec("rbd", "parent_detach", in_bl);
+}
+
+int parent_detach(librados::IoCtx *ioctx, const std::string &oid) {
+  librados::ObjectWriteOperation op;
+  parent_detach(&op);
+  return ioctx->operate(oid, &op);
+}
+
+int add_child(librados::IoCtx *ioctx, const std::string &oid,
+              const cls::rbd::ParentImageSpec &pspec,
+              const std::string &c_imageid)
+{
+  librados::ObjectWriteOperation op;
+  add_child(&op, pspec, c_imageid);
+  return ioctx->operate(oid, &op);
+}
+
+void add_child(librados::ObjectWriteOperation *op,
+               const cls::rbd::ParentImageSpec& pspec,
+               const std::string &c_imageid)
+{
+  assert(pspec.pool_namespace.empty());
+
+  bufferlist in;
+  encode(pspec.pool_id, in);
+  encode(pspec.image_id, in);
+  encode(pspec.snap_id, in);
+  encode(c_imageid, in);
+
+  op->exec("rbd", "add_child", in);
+}
+
+void remove_child(librados::ObjectWriteOperation *op,
+                  const cls::rbd::ParentImageSpec &pspec,
+                  const std::string &c_imageid)
+{
+  assert(pspec.pool_namespace.empty());
+
+  bufferlist in;
+  encode(pspec.pool_id, in);
+  encode(pspec.image_id, in);
+  encode(pspec.snap_id, in);
+  encode(c_imageid, in);
+  op->exec("rbd", "remove_child", in);
+}
+
+int remove_child(librados::IoCtx *ioctx, const std::string &oid,
+                 const cls::rbd::ParentImageSpec &pspec,
+                 const std::string &c_imageid)
+{
+  librados::ObjectWriteOperation op;
+  remove_child(&op, pspec, c_imageid);
+  return ioctx->operate(oid, &op);
+}
+
+void get_children_start(librados::ObjectReadOperation *op,
+                        const cls::rbd::ParentImageSpec &pspec) {
+  bufferlist in_bl;
+  encode(pspec.pool_id, in_bl);
+  encode(pspec.image_id, in_bl);
+  encode(pspec.snap_id, in_bl);
+  op->exec("rbd", "get_children", in_bl);
+}
+
+int get_children_finish(bufferlist::const_iterator *it,
+                        std::set<std::string>* children) {
+  try {
+    decode(*children, *it);
+  } catch (const ceph::buffer::error &err) {
+    return -EBADMSG;
+  }
+  return 0;
+}
+
+int get_children(librados::IoCtx *ioctx, const std::string &oid,
+                 const cls::rbd::ParentImageSpec &pspec, set<string>& children)
+{
+  librados::ObjectReadOperation op;
+  get_children_start(&op, pspec);
+
+  bufferlist out_bl;
+  int r = ioctx->operate(oid, &op, &out_bl);
+  if (r < 0) {
+    return r;
+  }
+
+  auto it = out_bl.cbegin();
+  return get_children_finish(&it, &children);
+}
+
+void snapshot_get_start(librados::ObjectReadOperation *op, snapid_t snap_id)
+{
+  bufferlist bl;
+  encode(snap_id, bl);
+  op->exec("rbd", "snapshot_get", bl);
+}
+
+int snapshot_get_finish(bufferlist::const_iterator* it,
+                        cls::rbd::SnapshotInfo* snap_info)
+{
+  try {
+    decode(*snap_info, *it);
+  } catch (const ceph::buffer::error &err) {
+    return -EBADMSG;
+  }
+  return 0;
+}
+
+int snapshot_get(librados::IoCtx *ioctx, const std::string &oid,
+                 snapid_t snap_id, cls::rbd::SnapshotInfo* snap_info)
+{
+  librados::ObjectReadOperation op;
+  snapshot_get_start(&op, snap_id);
+
+  bufferlist out_bl;
+  int r = ioctx->operate(oid, &op, &out_bl);
+  if (r < 0) {
+    return r;
+  }
+
+  auto it = out_bl.cbegin();
+  return snapshot_get_finish(&it, snap_info);
+}
+
+void snapshot_add(librados::ObjectWriteOperation *op, snapid_t snap_id,
+                  const std::string &snap_name,
+                  const cls::rbd::SnapshotNamespace &snap_namespace)
+{
+  bufferlist bl;
+  encode(snap_name, bl);
+  encode(snap_id, bl);
+  encode(snap_namespace, bl);
+  op->exec("rbd", "snapshot_add", bl);
+}
+
+void snapshot_remove(librados::ObjectWriteOperation *op, snapid_t snap_id)
+{
+  bufferlist bl;
+  encode(snap_id, bl);
+  op->exec("rbd", "snapshot_remove", bl);
+}
+
+void snapshot_rename(librados::ObjectWriteOperation *op,
+                     snapid_t src_snap_id,
+                     const std::string &dst_name)
+{
+  bufferlist bl;
+  encode(src_snap_id, bl);
+  encode(dst_name, bl);
+  op->exec("rbd", "snapshot_rename", bl);
+}
+
+void snapshot_trash_add(librados::ObjectWriteOperation *op,
+                        snapid_t snap_id)
+{
+  bufferlist bl;
+  encode(snap_id, bl);
+  op->exec("rbd", "snapshot_trash_add", bl);
+}
+
+void get_snapcontext_start(librados::ObjectReadOperation *op)
+{
+  bufferlist bl;
+  op->exec("rbd", "get_snapcontext", bl);
+}
+
+int get_snapcontext_finish(bufferlist::const_iterator *it,
+                           ::SnapContext *snapc)
+{
+  try {
+    decode(*snapc, *it);
+  } catch (const ceph::buffer::error &err) {
+    return -EBADMSG;
+  }
+  if (!snapc->is_valid()) {
+    return -EBADMSG;
+  }
+  return 0;
+}
+
+int get_snapcontext(librados::IoCtx *ioctx, const std::string &oid,
+                    ::SnapContext *snapc)
+{
+  librados::ObjectReadOperation op;
+  get_snapcontext_start(&op);
+
+  bufferlist out_bl;
+  int r = ioctx->operate(oid, &op, &out_bl);
+  if (r < 0) {
+    return r;
+  }
+
+  auto bl_it = out_bl.cbegin();
+  return get_snapcontext_finish(&bl_it, snapc);
+}
+
+void get_snapshot_name_start(librados::ObjectReadOperation *op,
+                             snapid_t snap_id)
+{
+  bufferlist bl;
+  encode(snap_id, bl);
+  op->exec("rbd", "get_snapshot_name", bl);
+}
+
+int get_snapshot_name_finish(bufferlist::const_iterator *it,
+                             std::string *name)
+{
+  try {
+    decode(*name, *it);
+  } catch (const ceph::buffer::error &err) {
+    return -EBADMSG;
+  }
+  return 0;
+}
+
+int get_snapshot_name(librados::IoCtx *ioctx, const std::string &oid,
+                      snapid_t snap_id, std::string *name)
+{
+  librados::ObjectReadOperation op;
+  get_snapshot_name_start(&op, snap_id);
+
+  bufferlist out_bl;
+  int r = ioctx->operate(oid, &op, &out_bl);
+  if (r < 0) {
+    return r;
+  }
+
+  auto it = out_bl.cbegin();
+  return get_snapshot_name_finish(&it, name);
+}
+
+void get_snapshot_timestamp_start(librados::ObjectReadOperation *op,
+                                  snapid_t snap_id)
+{
+  bufferlist bl;
+  encode(snap_id, bl);
+  op->exec("rbd", "get_snapshot_timestamp", bl);
+}
+
+int get_snapshot_timestamp_finish(bufferlist::const_iterator *it,
+                                  utime_t *timestamp)
+{
+  try {
+    decode(*timestamp, *it);
+  } catch (const ceph::buffer::error &err) {
+    return -EBADMSG;
+  }
+  return 0;
+}
+
+int get_snapshot_timestamp(librados::IoCtx *ioctx, const std::string &oid,
+                           snapid_t snap_id, utime_t *timestamp)
+{
+  librados::ObjectReadOperation op;
+  get_snapshot_timestamp_start(&op, snap_id);
+
+  bufferlist out_bl;
+  int r = ioctx->operate(oid, &op, &out_bl);
+  if (r < 0) {
+    return r;
+  }
+
+  auto it = out_bl.cbegin();
+  return get_snapshot_timestamp_finish(&it, timestamp);
+}
+
+void old_snapshot_add(librados::ObjectWriteOperation *op,
+                      snapid_t snap_id, const std::string &snap_name)
+{
+  bufferlist bl;
+  encode(snap_name, bl);
+  encode(snap_id, bl);
+  op->exec("rbd", "snap_add", bl);
+}
+
+void old_snapshot_remove(librados::ObjectWriteOperation *op,
+                         const std::string &snap_name)
+{
+  bufferlist bl;
+  encode(snap_name, bl);
+  op->exec("rbd", "snap_remove", bl);
+}
+
+void old_snapshot_rename(librados::ObjectWriteOperation *op,
+                         snapid_t src_snap_id, const std::string &dst_name)
+{
+  bufferlist bl;
+  encode(src_snap_id, bl);
+  encode(dst_name, bl);
+  op->exec("rbd", "snap_rename", bl);
+}
+
+void old_snapshot_list_start(librados::ObjectReadOperation *op) {
+  bufferlist in_bl;
+  op->exec("rbd", "snap_list", in_bl);
+}
+
+int old_snapshot_list_finish(bufferlist::const_iterator *it,
+                             std::vector<string> *names,
+                             std::vector<uint64_t> *sizes,
+                             ::SnapContext *snapc) {
+  try {
+    uint32_t num_snaps;
+    decode(snapc->seq, *it);
+    decode(num_snaps, *it);
+
+    names->resize(num_snaps);
+    sizes->resize(num_snaps);
+    snapc->snaps.resize(num_snaps);
+    for (uint32_t i = 0; i < num_snaps; ++i) {
+      decode(snapc->snaps[i], *it);
+      decode((*sizes)[i], *it);
+      decode((*names)[i], *it);
+    }
+  } catch (const ceph::buffer::error &err) {
+    return -EBADMSG;
+  }
+  return 0;
+}
+
+int old_snapshot_list(librados::IoCtx *ioctx, const std::string &oid,
+                      std::vector<string> *names,
+                      std::vector<uint64_t> *sizes,
+                      ::SnapContext *snapc)
+{
+  librados::ObjectReadOperation op;
+  old_snapshot_list_start(&op);
+
+  bufferlist out_bl;
+  int r = ioctx->operate(oid, &op, &out_bl);
+  if (r < 0) {
+    return r;
+  }
+
+  auto it = out_bl.cbegin();
+  return old_snapshot_list_finish(&it, names, sizes, snapc);
+}
+
+void get_all_features_start(librados::ObjectReadOperation *op) {
+  bufferlist in;
+  op->exec("rbd", "get_all_features", in);
+}
+
+int get_all_features_finish(bufferlist::const_iterator *it,
+                            uint64_t *all_features) {
+  try {
+    decode(*all_features, *it);
+  } catch (const ceph::buffer::error &err) {
+    return -EBADMSG;
+  }
+  return 0;
+}
+
+int get_all_features(librados::IoCtx *ioctx, const std::string &oid,
+                     uint64_t *all_features) {
+  librados::ObjectReadOperation op;
+  get_all_features_start(&op);
+
+  bufferlist out_bl;
+  int r = ioctx->operate(oid, &op, &out_bl);
+  if (r < 0) {
+    return r;
+  }
+
+  auto it = out_bl.cbegin();
+  return get_all_features_finish(&it, all_features);
+}
+
+template <typename O>
+void copyup(O* op, ceph::buffer::list data) {
+  op->exec("rbd", "copyup", data);
+}
+
+void copyup(neorados::WriteOp* op, ceph::buffer::list data) {
+  copyup<neorados::WriteOp>(op, data);
+}
+
+void copyup(librados::ObjectWriteOperation *op, bufferlist data) {
+  copyup<librados::ObjectWriteOperation>(op, data);
+}
+
+int copyup(librados::IoCtx *ioctx, const std::string &oid,
+           bufferlist data) {
+  librados::ObjectWriteOperation op;
+  copyup(&op, data);
+
+  return ioctx->operate(oid, &op);
+}
+
+template <typename O, typename E>
+void sparse_copyup(O* op, const E& extent_map, ceph::buffer::list data) {
+  bufferlist bl;
+  encode(extent_map, bl);
+  encode(data, bl);
+  op->exec("rbd", "sparse_copyup", bl);
+}
+
+void sparse_copyup(neorados::WriteOp* op,
+                   const std::vector<std::pair<uint64_t, uint64_t>>& extent_map,
+                   ceph::buffer::list data) {
+  sparse_copyup<neorados::WriteOp>(op, extent_map, data);
+}
+
+void sparse_copyup(librados::ObjectWriteOperation *op,
+                   const std::map<uint64_t, uint64_t> &extent_map,
+                   bufferlist data) {
+  sparse_copyup<librados::ObjectWriteOperation>(op, extent_map, data);
+}
+
+int sparse_copyup(librados::IoCtx *ioctx, const std::string &oid,
+                  const std::map<uint64_t, uint64_t> &extent_map,
+                  bufferlist data) {
+  librados::ObjectWriteOperation op;
+  sparse_copyup(&op, extent_map, data);
+
+  return ioctx->operate(oid, &op);
+}
+
+void get_protection_status_start(librados::ObjectReadOperation *op,
+                                 snapid_t snap_id)
+{
+  bufferlist bl;
+  encode(snap_id, bl);
+  op->exec("rbd", "get_protection_status", bl);
+}
+
+int get_protection_status_finish(bufferlist::const_iterator *it,
+                                 uint8_t *protection_status)
+{
+  try {
+    decode(*protection_status, *it);
+  } catch (const ceph::buffer::error &) {
+    return -EBADMSG;
+  }
+  return 0;
+}
+
+int get_protection_status(librados::IoCtx *ioctx, const std::string &oid,
+                          snapid_t snap_id, uint8_t *protection_status)
+{
+  librados::ObjectReadOperation op;
+  get_protection_status_start(&op, snap_id);
+
+  bufferlist out_bl;
+  int r = ioctx->operate(oid, &op, &out_bl);
+  if (r < 0) {
+    return r;
+  }
+
+  auto it = out_bl.cbegin();
+  return get_protection_status_finish(&it, protection_status);
+}
+
+int set_protection_status(librados::IoCtx *ioctx, const std::string &oid,
+                          snapid_t snap_id, uint8_t protection_status)
+{
+  // TODO remove
+  librados::ObjectWriteOperation op;
+  set_protection_status(&op, snap_id, protection_status);
+  return ioctx->operate(oid, &op);
+}
+
+void set_protection_status(librados::ObjectWriteOperation *op,
+                           snapid_t snap_id, uint8_t protection_status)
+{
+  bufferlist in;
+  encode(snap_id, in);
+  encode(protection_status, in);
+  op->exec("rbd", "set_protection_status", in);
+}
+
+void snapshot_get_limit_start(librados::ObjectReadOperation *op)
+{
+  bufferlist bl;
+  op->exec("rbd", "snapshot_get_limit", bl);
+}
+
+int snapshot_get_limit_finish(bufferlist::const_iterator *it, uint64_t *limit)
+{
+  try {
+    decode(*limit, *it);
+  } catch (const ceph::buffer::error &err) {
+    return -EBADMSG;
+  }
+  return 0;
+}
+
+int snapshot_get_limit(librados::IoCtx *ioctx, const std::string &oid,
+                       uint64_t *limit)
+{
+  librados::ObjectReadOperation op;
+  snapshot_get_limit_start(&op);
+
+  bufferlist out_bl;
+  int r = ioctx->operate(oid, &op, &out_bl);
+  if (r < 0) {
+    return r;
+  }
+
+  auto it = out_bl.cbegin();
+  return snapshot_get_limit_finish(&it, limit);
+}
+
+void snapshot_set_limit(librados::ObjectWriteOperation *op, uint64_t limit)
+{
+  bufferlist in;
+  encode(limit, in);
+  op->exec("rbd", "snapshot_set_limit", in);
+}
+
+void get_stripe_unit_count_start(librados::ObjectReadOperation *op) {
+  bufferlist empty_bl;
+  op->exec("rbd", "get_stripe_unit_count", empty_bl);
+}
+
+int get_stripe_unit_count_finish(bufferlist::const_iterator *it,
+                                 uint64_t *stripe_unit,
+                                 uint64_t *stripe_count) {
+  ceph_assert(stripe_unit);
+  ceph_assert(stripe_count);
+
+  try {
+    decode(*stripe_unit, *it);
+    decode(*stripe_count, *it);
+  } catch (const ceph::buffer::error &err) {
+    return -EBADMSG;
+  }
+  return 0;
+}
+
+int get_stripe_unit_count(librados::IoCtx *ioctx, const std::string &oid,
+                          uint64_t *stripe_unit, uint64_t *stripe_count)
+{
+  librados::ObjectReadOperation op;
+  get_stripe_unit_count_start(&op);
+
+  bufferlist out_bl;
+  int r = ioctx->operate(oid, &op, &out_bl);
+  if (r < 0) {
+    return r;
+  }
+
+  auto it = out_bl.cbegin();
+  return get_stripe_unit_count_finish(&it, stripe_unit, stripe_count);
+}
+
+void set_stripe_unit_count(librados::ObjectWriteOperation *op,
+                           uint64_t stripe_unit, uint64_t stripe_count)
+{
+  bufferlist bl;
+  encode(stripe_unit, bl);
+  encode(stripe_count, bl);
+
+  op->exec("rbd", "set_stripe_unit_count", bl);
+}
+
+int set_stripe_unit_count(librados::IoCtx *ioctx, const std::string &oid,
+                          uint64_t stripe_unit, uint64_t stripe_count)
+{
+  librados::ObjectWriteOperation op;
+  set_stripe_unit_count(&op, stripe_unit, stripe_count);
+
+  return ioctx->operate(oid, &op);
+}
+
+void get_create_timestamp_start(librados::ObjectReadOperation *op) {
+  bufferlist empty_bl;
+  op->exec("rbd", "get_create_timestamp", empty_bl);
+}
+
+int get_create_timestamp_finish(bufferlist::const_iterator *it,
+                                utime_t *timestamp) {
+  ceph_assert(timestamp);
+
+  try {
+    decode(*timestamp, *it);
+  } catch (const ceph::buffer::error &err) {
+    return -EBADMSG;
+  }
+  return 0;
+}
+
+int get_create_timestamp(librados::IoCtx *ioctx, const std::string &oid,
+                         utime_t *timestamp)
+{
+  librados::ObjectReadOperation op;
+  get_create_timestamp_start(&op);
+
+  bufferlist out_bl;
+  int r = ioctx->operate(oid, &op, &out_bl);
+  if (r < 0) {
+    return r;
+  }
+
+  auto it = out_bl.cbegin();
+  return get_create_timestamp_finish(&it, timestamp);
+}
+
+void get_access_timestamp_start(librados::ObjectReadOperation *op) {
+  bufferlist empty_bl;
+  op->exec("rbd", "get_access_timestamp", empty_bl);
+}
+
+int get_access_timestamp_finish(bufferlist::const_iterator *it,
+                                utime_t *timestamp) {
+  ceph_assert(timestamp);
+
+  try {
+    decode(*timestamp, *it);
+  } catch (const ceph::buffer::error &err) {
+    return -EBADMSG;
+  }
+  return 0;
+}
+
+int get_access_timestamp(librados::IoCtx *ioctx, const std::string &oid,
+                         utime_t *timestamp)
+{
+  librados::ObjectReadOperation op;
+  get_access_timestamp_start(&op);
+
+  bufferlist out_bl;
+  int r = ioctx->operate(oid, &op, &out_bl);
+  if (r < 0) {
+    return r;
+  }
+
+  auto it = out_bl.cbegin();
+  return get_access_timestamp_finish(&it, timestamp);
+}
+
+void set_access_timestamp(librados::ObjectWriteOperation *op)
+{
+    bufferlist empty_bl;
+    op->exec("rbd","set_access_timestamp",empty_bl);
+}
+
+int set_access_timestamp(librados::IoCtx *ioctx, const std::string &oid)
+{
+    librados::ObjectWriteOperation op;
+    set_access_timestamp(&op);
+    return ioctx->operate(oid, &op);
+}
+
+void get_modify_timestamp_start(librados::ObjectReadOperation *op) {
+  bufferlist empty_bl;
+  op->exec("rbd", "get_modify_timestamp", empty_bl);
+}
+
+int get_modify_timestamp_finish(bufferlist::const_iterator *it,
+                                  utime_t *timestamp) {
+  ceph_assert(timestamp);
+
+  try {
+    decode(*timestamp, *it);
+  } catch (const ceph::buffer::error &err) {
+    return -EBADMSG;
+  }
+  return 0;
+}
+
+int get_modify_timestamp(librados::IoCtx *ioctx, const std::string &oid,
+                           utime_t *timestamp)
+{
+  librados::ObjectReadOperation op;
+  get_modify_timestamp_start(&op);
+
+  bufferlist out_bl;
+  int r = ioctx->operate(oid, &op, &out_bl);
+  if (r < 0) {
+    return r;
+  }
+
+  auto it = out_bl.cbegin();
+  return get_modify_timestamp_finish(&it, timestamp);
+}
+
+void set_modify_timestamp(librados::ObjectWriteOperation *op)
+{
+    bufferlist empty_bl;
+    op->exec("rbd","set_modify_timestamp",empty_bl);
+}
+
+int set_modify_timestamp(librados::IoCtx *ioctx, const std::string &oid)
+{
+    librados::ObjectWriteOperation op;
+    set_modify_timestamp(&op);
+    return ioctx->operate(oid, &op);
+}
+
+
+/************************ rbd_id object methods ************************/
+
+void get_id_start(librados::ObjectReadOperation *op) {
+  bufferlist empty_bl;
+  op->exec("rbd", "get_id", empty_bl);
+}
+
+int get_id_finish(bufferlist::const_iterator *it, std::string *id) {
+  try {
+    decode(*id, *it);
+  } catch (const ceph::buffer::error &err) {
+    return -EBADMSG;
+  }
+  return 0;
+}
+
+int get_id(librados::IoCtx *ioctx, const std::string &oid, std::string *id)
+{
+  librados::ObjectReadOperation op;
+  get_id_start(&op);
+
+  bufferlist out_bl;
+  int r = ioctx->operate(oid, &op, &out_bl);
+  if (r < 0) {
+    return r;
+  }
+
+  auto it = out_bl.cbegin();
+  return get_id_finish(&it, id);
+}
+
+void set_id(librados::ObjectWriteOperation *op, const std::string &id)
+{
+  bufferlist bl;
+  encode(id, bl);
+  op->exec("rbd", "set_id", bl);
+}
+
+int set_id(librados::IoCtx *ioctx, const std::string &oid, const std::string &id)
+{
+  librados::ObjectWriteOperation op;
+  set_id(&op, id);
+
+  return ioctx->operate(oid, &op);
+}
+
+/******************** rbd_directory object methods ********************/
+
+void dir_get_id_start(librados::ObjectReadOperation *op,
+                      const std::string &image_name) {
+  bufferlist bl;
+  encode(image_name, bl);
+
+  op->exec("rbd", "dir_get_id", bl);
+}
+
+int dir_get_id_finish(bufferlist::const_iterator *iter, std::string *image_id) {
+  try {
+    decode(*image_id, *iter);
+  } catch (const ceph::buffer::error &err) {
+    return -EBADMSG;
+  }
+
+  return 0;
+}
+
+int dir_get_id(librados::IoCtx *ioctx, const std::string &oid,
+               const std::string &name, std::string *id) {
+  librados::ObjectReadOperation op;
+  dir_get_id_start(&op, name);
+
+  bufferlist out_bl;
+  int r = ioctx->operate(oid, &op, &out_bl);
+  if (r < 0) {
+    return r;
+  }
+
+  auto iter = out_bl.cbegin();
+  return dir_get_id_finish(&iter, id);
+}
+
+void dir_get_name_start(librados::ObjectReadOperation *op,
+                        const std::string &id) {
+  bufferlist in_bl;
+  encode(id, in_bl);
+  op->exec("rbd", "dir_get_name", in_bl);
+}
+
+int dir_get_name_finish(bufferlist::const_iterator *it, std::string *name) {
+  try {
+    decode(*name, *it);
+  } catch (const ceph::buffer::error &err) {
+    return -EBADMSG;
+  }
+  return 0;
+}
+
+int dir_get_name(librados::IoCtx *ioctx, const std::string &oid,
+                 const std::string &id, std::string *name) {
+  librados::ObjectReadOperation op;
+  dir_get_name_start(&op, id);
+
+  bufferlist out_bl;
+  int r = ioctx->operate(oid, &op, &out_bl);
+  if (r < 0) {
+    return r;
+  }
+
+  auto it = out_bl.cbegin();
+  return dir_get_name_finish(&it, name);
+}
+
+void dir_list_start(librados::ObjectReadOperation *op,
+                    const std::string &start, uint64_t max_return)
+{
+  bufferlist in_bl;
+  encode(start, in_bl);
+  encode(max_return, in_bl);
+
+  op->exec("rbd", "dir_list", in_bl);
+}
+
+int dir_list_finish(bufferlist::const_iterator *it, map<string, string> *images)
+{
+  try {
+    decode(*images, *it);
+  } catch (const ceph::buffer::error &err) {
+    return -EBADMSG;
+  }
+  return 0;
+}
+
+int dir_list(librados::IoCtx *ioctx, const std::string &oid,
+             const std::string &start, uint64_t max_return,
+             map<string, string> *images)
+{
+  librados::ObjectReadOperation op;
+  dir_list_start(&op, start, max_return);
+
+  bufferlist out_bl;
+  int r = ioctx->operate(oid, &op, &out_bl);
+  if (r < 0) {
+    return r;
+  }
+
+  auto iter = out_bl.cbegin();
+  return dir_list_finish(&iter, images);
+}
+
+void dir_add_image(librados::ObjectWriteOperation *op,
+                   const std::string &name, const std::string &id)
+{
+  bufferlist bl;
+  encode(name, bl);
+  encode(id, bl);
+  op->exec("rbd", "dir_add_image", bl);
+}
+
+int dir_add_image(librados::IoCtx *ioctx, const std::string &oid,
+                  const std::string &name, const std::string &id)
+{
+  librados::ObjectWriteOperation op;
+  dir_add_image(&op, name, id);
+
+  return ioctx->operate(oid, &op);
+}
+
+int dir_remove_image(librados::IoCtx *ioctx, const std::string &oid,
+                     const std::string &name, const std::string &id)
+{
+  librados::ObjectWriteOperation op;
+  dir_remove_image(&op, name, id);
+
+  return ioctx->operate(oid, &op);
+}
+
+void dir_state_assert(librados::ObjectOperation *op,
+                      cls::rbd::DirectoryState directory_state)
+{
+  bufferlist bl;
+  encode(directory_state, bl);
+  op->exec("rbd", "dir_state_assert", bl);
+}
+
+int dir_state_assert(librados::IoCtx *ioctx, const std::string &oid,
+                     cls::rbd::DirectoryState directory_state)
+{
+  librados::ObjectWriteOperation op;
+  dir_state_assert(&op, directory_state);
+
+  return ioctx->operate(oid, &op);
+}
+
+void dir_state_set(librados::ObjectWriteOperation *op,
+                   cls::rbd::DirectoryState directory_state)
+{
+  bufferlist bl;
+  encode(directory_state, bl);
+  op->exec("rbd", "dir_state_set", bl);
+}
+
+int dir_state_set(librados::IoCtx *ioctx, const std::string &oid,
+                  cls::rbd::DirectoryState directory_state)
+{
+  librados::ObjectWriteOperation op;
+  dir_state_set(&op, directory_state);
+
+  return ioctx->operate(oid, &op);
+}
+
+void dir_remove_image(librados::ObjectWriteOperation *op,
+                      const std::string &name, const std::string &id)
+{
+  bufferlist bl;
+  encode(name, bl);
+  encode(id, bl);
+
+  op->exec("rbd", "dir_remove_image", bl);
+}
+
+void dir_rename_image(librados::ObjectWriteOperation *op,
+                      const std::string &src, const std::string &dest,
+                      const std::string &id)
+{
+  bufferlist in;
+  encode(src, in);
+  encode(dest, in);
+  encode(id, in);
+  op->exec("rbd", "dir_rename_image", in);
+}
+
+void object_map_load_start(librados::ObjectReadOperation *op) {
+  bufferlist in_bl;
+  op->exec("rbd", "object_map_load", in_bl);
+}
+
+int object_map_load_finish(bufferlist::const_iterator *it,
+                           ceph::BitVector<2> *object_map) {
+  try {
+    decode(*object_map, *it);
+  } catch (const ceph::buffer::error &err) {
+    return -EBADMSG;
+  }
+  return 0;
+}
+
+int object_map_load(librados::IoCtx *ioctx, const std::string &oid,
+                    ceph::BitVector<2> *object_map)
+{
+  librados::ObjectReadOperation op;
+  object_map_load_start(&op);
+
+  bufferlist out_bl;
+  int r = ioctx->operate(oid, &op, &out_bl);
+  if (r < 0) {
+    return r;
+  }
+
+  auto it = out_bl.cbegin();
+  return object_map_load_finish(&it, object_map);
+}
+
+void object_map_save(librados::ObjectWriteOperation *rados_op,
+                     const ceph::BitVector<2> &object_map)
+{
+  ceph::BitVector<2> object_map_copy(object_map);
+  object_map_copy.set_crc_enabled(false);
+
+  bufferlist in;
+  encode(object_map_copy, in);
+  rados_op->exec("rbd", "object_map_save", in);
+}
+
+void object_map_resize(librados::ObjectWriteOperation *rados_op,
+                       uint64_t object_count, uint8_t default_state)
+{
+  bufferlist in;
+  encode(object_count, in);
+  encode(default_state, in);
+  rados_op->exec("rbd", "object_map_resize", in);
+}
+
+void object_map_update(librados::ObjectWriteOperation *rados_op,
+                       uint64_t start_object_no, uint64_t end_object_no,
+                       uint8_t new_object_state,
+                       const boost::optional<uint8_t> &current_object_state)
+{
+  bufferlist in;
+  encode(start_object_no, in);
+  encode(end_object_no, in);
+  encode(new_object_state, in);
+  encode(current_object_state, in);
+  rados_op->exec("rbd", "object_map_update", in);
+}
+
+void object_map_snap_add(librados::ObjectWriteOperation *rados_op)
+{
+  bufferlist in;
+  rados_op->exec("rbd", "object_map_snap_add", in);
+}
+
+void object_map_snap_remove(librados::ObjectWriteOperation *rados_op,
+                            const ceph::BitVector<2> &object_map)
+{
+  ceph::BitVector<2> object_map_copy(object_map);
+  object_map_copy.set_crc_enabled(false);
+
+  bufferlist in;
+  encode(object_map_copy, in);
+  rados_op->exec("rbd", "object_map_snap_remove", in);
+}
+
+void metadata_set(librados::ObjectWriteOperation *op,
+                  const map<string, bufferlist> &data)
+{
+  bufferlist bl;
+  encode(data, bl);
+
+  op->exec("rbd", "metadata_set", bl);
+}
+
+int metadata_set(librados::IoCtx *ioctx, const std::string &oid,
+                 const map<string, bufferlist> &data)
+{
+  librados::ObjectWriteOperation op;
+  metadata_set(&op, data);
+
+  return ioctx->operate(oid, &op);
+}
+
+void metadata_remove(librados::ObjectWriteOperation *op,
+                     const std::string &key)
+{
+  bufferlist bl;
+  encode(key, bl);
+
+  op->exec("rbd", "metadata_remove", bl);
+}
+
+int metadata_remove(librados::IoCtx *ioctx, const std::string &oid,
+                    const std::string &key)
+{
+  librados::ObjectWriteOperation op;
+  metadata_remove(&op, key);
+
+  return ioctx->operate(oid, &op);
+}
+
+int metadata_list(librados::IoCtx *ioctx, const std::string &oid,
+                  const std::string &start, uint64_t max_return,
+                  map<string, bufferlist> *pairs)
+{
+  librados::ObjectReadOperation op;
+  metadata_list_start(&op, start, max_return);
+
+  bufferlist out_bl;
+  int r = ioctx->operate(oid, &op, &out_bl);
+  if (r < 0) {
+    return r;
+  }
+
+  auto it = out_bl.cbegin();
+  return metadata_list_finish(&it, pairs);
+}
+
+void metadata_list_start(librados::ObjectReadOperation *op,
+                         const std::string &start, uint64_t max_return)
+{
+  bufferlist in_bl;
+  encode(start, in_bl);
+  encode(max_return, in_bl);
+  op->exec("rbd", "metadata_list", in_bl);
+}
+
+int metadata_list_finish(bufferlist::const_iterator *it,
+                         std::map<std::string, bufferlist> *pairs)
+{
+  ceph_assert(pairs);
+  try {
+    decode(*pairs, *it);
+  } catch (const ceph::buffer::error &err) {
+    return -EBADMSG;
+  }
+  return 0;
+}
+
+void metadata_get_start(librados::ObjectReadOperation* op,
+                 const std::string &key) {
+  bufferlist bl;
+  encode(key, bl);
+
+  op->exec("rbd", "metadata_get", bl);
+}
+
+int metadata_get_finish(bufferlist::const_iterator *it,
+                         std::string* value) {
+  try {
+    decode(*value, *it);
+  } catch (const ceph::buffer::error &err) {
+    return -EBADMSG;
+  }
+  return 0;
+}
+
+int metadata_get(librados::IoCtx *ioctx, const std::string &oid,
+                 const std::string &key, string *s)
+{
+  ceph_assert(s);
+  librados::ObjectReadOperation op;
+  metadata_get_start(&op, key);
+
+  bufferlist out_bl;
+  int r = ioctx->operate(oid, &op, &out_bl);
+  if (r < 0) {
+    return r;
+  }
+
+  auto it = out_bl.cbegin();
+  r = metadata_get_finish(&it, s);
+  if (r < 0) {
+    return r;
+  }
+  return 0;
+}
+
+void child_attach(librados::ObjectWriteOperation *op, snapid_t snap_id,
+                  const cls::rbd::ChildImageSpec& child_image)
+{
+  bufferlist bl;
+  encode(snap_id, bl);
+  encode(child_image, bl);
+  op->exec("rbd", "child_attach", bl);
+}
+
+int child_attach(librados::IoCtx *ioctx, const std::string &oid,
+                 snapid_t snap_id,
+                 const cls::rbd::ChildImageSpec& child_image)
+{
+  librados::ObjectWriteOperation op;
+  child_attach(&op, snap_id, child_image);
+
+  int r = ioctx->operate(oid, &op);
+  if (r < 0) {
+    return r;
+  }
+  return 0;
+}
+
+void child_detach(librados::ObjectWriteOperation *op, snapid_t snap_id,
+                  const cls::rbd::ChildImageSpec& child_image)
+{
+  bufferlist bl;
+  encode(snap_id, bl);
+  encode(child_image, bl);
+  op->exec("rbd", "child_detach", bl);
+}
+
+int child_detach(librados::IoCtx *ioctx, const std::string &oid,
+                 snapid_t snap_id,
+                 const cls::rbd::ChildImageSpec& child_image)
+{
+  librados::ObjectWriteOperation op;
+  child_detach(&op, snap_id, child_image);
+
+  int r = ioctx->operate(oid, &op);
+  if (r < 0) {
+    return r;
+  }
+  return 0;
+}
+
+void children_list_start(librados::ObjectReadOperation *op,
+                         snapid_t snap_id)
+{
+  bufferlist bl;
+  encode(snap_id, bl);
+  op->exec("rbd", "children_list", bl);
+}
+
+int children_list_finish(bufferlist::const_iterator *it,
+                         cls::rbd::ChildImageSpecs *child_images)
+{
+  child_images->clear();
+  try {
+    decode(*child_images, *it);
+  } catch (const ceph::buffer::error &err) {
+    return -EBADMSG;
+  }
+  return 0;
+}
+
+int children_list(librados::IoCtx *ioctx, const std::string &oid,
+                  snapid_t snap_id,
+                  cls::rbd::ChildImageSpecs *child_images)
+{
+  librados::ObjectReadOperation op;
+  children_list_start(&op, snap_id);
+
+  bufferlist out_bl;
+  int r = ioctx->operate(oid, &op, &out_bl);
+  if (r < 0) {
+    return r;
+  }
+
+  auto it = out_bl.cbegin();
+  r = children_list_finish(&it, child_images);
+  if (r < 0) {
+    return r;
+  }
+  return 0;
+}
+
+int migration_set(librados::IoCtx *ioctx, const std::string &oid,
+                  const cls::rbd::MigrationSpec &migration_spec) {
+  librados::ObjectWriteOperation op;
+  migration_set(&op, migration_spec);
+  return ioctx->operate(oid, &op);
+}
+
+void migration_set(librados::ObjectWriteOperation *op,
+                   const cls::rbd::MigrationSpec &migration_spec) {
+  bufferlist bl;
+  encode(migration_spec, bl);
+  op->exec("rbd", "migration_set", bl);
+}
+
+int migration_set_state(librados::IoCtx *ioctx, const std::string &oid,
+                        cls::rbd::MigrationState state,
+                        const std::string &description) {
+  librados::ObjectWriteOperation op;
+  migration_set_state(&op, state, description);
+  return ioctx->operate(oid, &op);
+}
+
+void migration_set_state(librados::ObjectWriteOperation *op,
+                         cls::rbd::MigrationState state,
+                         const std::string &description) {
+  bufferlist bl;
+  encode(state, bl);
+  encode(description, bl);
+  op->exec("rbd", "migration_set_state", bl);
+}
+
+void migration_get_start(librados::ObjectReadOperation *op) {
+  bufferlist bl;
+  op->exec("rbd", "migration_get", bl);
+}
+
+int migration_get_finish(bufferlist::const_iterator *it,
+                         cls::rbd::MigrationSpec *migration_spec) {
+  try {
+    decode(*migration_spec, *it);
+  } catch (const ceph::buffer::error &err) {
+    return -EBADMSG;
+  }
+  return 0;
+}
+
+int migration_get(librados::IoCtx *ioctx, const std::string &oid,
+                  cls::rbd::MigrationSpec *migration_spec) {
+  librados::ObjectReadOperation op;
+  migration_get_start(&op);
+
+  bufferlist out_bl;
+  int r = ioctx->operate(oid, &op, &out_bl);
+  if (r < 0) {
+    return r;
+  }
+
+  auto iter = out_bl.cbegin();
+  r = migration_get_finish(&iter, migration_spec);
+  if (r < 0) {
+    return r;
+  }
+  return 0;
+}
+
+int migration_remove(librados::IoCtx *ioctx, const std::string &oid) {
+  librados::ObjectWriteOperation op;
+  migration_remove(&op);
+  return ioctx->operate(oid, &op);
+}
+
+void migration_remove(librados::ObjectWriteOperation *op) {
+  bufferlist bl;
+  op->exec("rbd", "migration_remove", bl);
+}
+
+template <typename O>
+void assert_snapc_seq(O* op, uint64_t snapc_seq,
+                      cls::rbd::AssertSnapcSeqState state) {
+  bufferlist bl;
+  encode(snapc_seq, bl);
+  encode(state, bl);
+  op->exec("rbd", "assert_snapc_seq", bl);
+}
+
+void assert_snapc_seq(neorados::WriteOp* op,
+                      uint64_t snapc_seq,
+                      cls::rbd::AssertSnapcSeqState state) {
+  assert_snapc_seq<neorados::WriteOp>(op, snapc_seq, state);
+}
+
+void assert_snapc_seq(librados::ObjectWriteOperation *op,
+                      uint64_t snapc_seq,
+                      cls::rbd::AssertSnapcSeqState state) {
+  assert_snapc_seq<librados::ObjectWriteOperation>(op, snapc_seq, state);
+}
+
+int assert_snapc_seq(librados::IoCtx *ioctx, const std::string &oid,
+                     uint64_t snapc_seq,
+                     cls::rbd::AssertSnapcSeqState state) {
+  librados::ObjectWriteOperation op;
+  assert_snapc_seq(&op, snapc_seq, state);
+  return ioctx->operate(oid, &op);
+}
+
+void mirror_uuid_get_start(librados::ObjectReadOperation *op) {
+  bufferlist bl;
+  op->exec("rbd", "mirror_uuid_get", bl);
+}
+
+int mirror_uuid_get_finish(bufferlist::const_iterator *it,
+                           std::string *uuid) {
+  try {
+    decode(*uuid, *it);
+  } catch (const ceph::buffer::error &err) {
+    return -EBADMSG;
+  }
+  return 0;
+}
+
+int mirror_uuid_get(librados::IoCtx *ioctx, std::string *uuid) {
+  librados::ObjectReadOperation op;
+  mirror_uuid_get_start(&op);
+
+  bufferlist out_bl;
+  int r = ioctx->operate(RBD_MIRRORING, &op, &out_bl);
+  if (r < 0) {
+    return r;
+  }
+
+  auto it = out_bl.cbegin();
+  r = mirror_uuid_get_finish(&it, uuid);
+  if (r < 0) {
+    return r;
+  }
+  return 0;
+}
+
+int mirror_uuid_set(librados::IoCtx *ioctx, const std::string &uuid) {
+  bufferlist in_bl;
+  encode(uuid, in_bl);
+
+  bufferlist out_bl;
+  int r = ioctx->exec(RBD_MIRRORING, "rbd", "mirror_uuid_set", in_bl,
+                      out_bl);
+  if (r < 0) {
+    return r;
+  }
+  return 0;
+}
+
+void mirror_mode_get_start(librados::ObjectReadOperation *op) {
+  bufferlist bl;
+  op->exec("rbd", "mirror_mode_get", bl);
+}
+
+int mirror_mode_get_finish(bufferlist::const_iterator *it,
+                           cls::rbd::MirrorMode *mirror_mode) {
+  try {
+    uint32_t mirror_mode_decode;
+    decode(mirror_mode_decode, *it);
+    *mirror_mode = static_cast<cls::rbd::MirrorMode>(mirror_mode_decode);
+  } catch (const ceph::buffer::error &err) {
+    return -EBADMSG;
+  }
+
+  return 0;
+}
+
+int mirror_mode_get(librados::IoCtx *ioctx,
+                    cls::rbd::MirrorMode *mirror_mode) {
+  librados::ObjectReadOperation op;
+  mirror_mode_get_start(&op);
+
+  bufferlist out_bl;
+  int r = ioctx->operate(RBD_MIRRORING, &op, &out_bl);
+  if (r == -ENOENT) {
+    *mirror_mode = cls::rbd::MIRROR_MODE_DISABLED;
+    return 0;
+  } else if (r < 0) {
+    return r;
+  }
+
+  auto it = out_bl.cbegin();
+  r = mirror_mode_get_finish(&it, mirror_mode);
+  if (r < 0) {
+    return r;
+  }
+  return 0;
+}
+
+int mirror_mode_set(librados::IoCtx *ioctx,
+                    cls::rbd::MirrorMode mirror_mode) {
+  bufferlist in_bl;
+  encode(static_cast<uint32_t>(mirror_mode), in_bl);
+
+  bufferlist out_bl;
+  int r = ioctx->exec(RBD_MIRRORING, "rbd", "mirror_mode_set", in_bl,
+                      out_bl);
+  if (r < 0) {
+    return r;
+  }
+  return 0;
+}
+
+void mirror_peer_list_start(librados::ObjectReadOperation *op) {
+  bufferlist bl;
+  op->exec("rbd", "mirror_peer_list", bl);
+}
+
+int mirror_peer_list_finish(bufferlist::const_iterator *it,
+                            std::vector<cls::rbd::MirrorPeer> *peers) {
+  peers->clear();
+  try {
+    decode(*peers, *it);
+  } catch (const ceph::buffer::error &err) {
+    return -EBADMSG;
+  }
+  return 0;
+}
+
+int mirror_peer_list(librados::IoCtx *ioctx,
+                     std::vector<cls::rbd::MirrorPeer> *peers) {
+  librados::ObjectReadOperation op;
+  mirror_peer_list_start(&op);
+
+  bufferlist out_bl;
+  int r = ioctx->operate(RBD_MIRRORING, &op, &out_bl);
+  if (r < 0) {
+    return r;
+  }
+
+  auto it = out_bl.cbegin();
+  r = mirror_peer_list_finish(&it, peers);
+  if (r < 0) {
+    return r;
+  }
+  return 0;
+}
+
+int mirror_peer_ping(librados::IoCtx *ioctx,
+                     const std::string& site_name,
+                     const std::string& fsid) {
+  librados::ObjectWriteOperation op;
+  mirror_peer_ping(&op, site_name, fsid);
+
+  int r = ioctx->operate(RBD_MIRRORING, &op);
+  if (r < 0) {
+    return r;
+  }
+
+  return 0;
+}
+
+void mirror_peer_ping(librados::ObjectWriteOperation *op,
+                      const std::string& site_name,
+                      const std::string& fsid) {
+  bufferlist in_bl;
+  encode(site_name, in_bl);
+  encode(fsid, in_bl);
+  encode(static_cast<uint8_t>(cls::rbd::MIRROR_PEER_DIRECTION_TX), in_bl);
+
+  op->exec("rbd", "mirror_peer_ping", in_bl);
+}
+
+int mirror_peer_add(librados::IoCtx *ioctx,
+                    const cls::rbd::MirrorPeer& mirror_peer) {
+  librados::ObjectWriteOperation op;
+  mirror_peer_add(&op, mirror_peer);
+
+  int r = ioctx->operate(RBD_MIRRORING, &op);
+  if (r < 0) {
+    return r;
+  }
+
+  return 0;
+}
+
+void mirror_peer_add(librados::ObjectWriteOperation *op,
+                     const cls::rbd::MirrorPeer& mirror_peer) {
+  bufferlist in_bl;
+  encode(mirror_peer, in_bl);
+
+  op->exec("rbd", "mirror_peer_add", in_bl);
+}
+
+int mirror_peer_remove(librados::IoCtx *ioctx,
+                       const std::string &uuid) {
+  bufferlist in_bl;
+  encode(uuid, in_bl);
+
+  bufferlist out_bl;
+  int r = ioctx->exec(RBD_MIRRORING, "rbd", "mirror_peer_remove", in_bl,
+                      out_bl);
+  if (r < 0) {
+    return r;
+  }
+  return 0;
+}
+
+int mirror_peer_set_client(librados::IoCtx *ioctx,
+                           const std::string &uuid,
+                           const std::string &client_name) {
+  bufferlist in_bl;
+  encode(uuid, in_bl);
+  encode(client_name, in_bl);
+
+  bufferlist out_bl;
+  int r = ioctx->exec(RBD_MIRRORING, "rbd", "mirror_peer_set_client",
+                      in_bl, out_bl);
+  if (r < 0) {
+    return r;
+  }
+  return 0;
+}
+
+int mirror_peer_set_cluster(librados::IoCtx *ioctx,
+                            const std::string &uuid,
+                            const std::string &cluster_name) {
+  bufferlist in_bl;
+  encode(uuid, in_bl);
+  encode(cluster_name, in_bl);
+
+  bufferlist out_bl;
+  int r = ioctx->exec(RBD_MIRRORING, "rbd", "mirror_peer_set_cluster",
+                      in_bl, out_bl);
+  if (r < 0) {
+    return r;
+  }
+  return 0;
+}
+
+int mirror_peer_set_direction(
+    librados::IoCtx *ioctx, const std::string &uuid,
+    cls::rbd::MirrorPeerDirection mirror_peer_direction) {
+  bufferlist in_bl;
+  encode(uuid, in_bl);
+  encode(static_cast<uint8_t>(mirror_peer_direction), in_bl);
+
+  bufferlist out_bl;
+  int r = ioctx->exec(RBD_MIRRORING, "rbd", "mirror_peer_set_direction",
+                      in_bl, out_bl);
+  if (r < 0) {
+    return r;
+  }
+  return 0;
+}
+
+void mirror_image_list_start(librados::ObjectReadOperation *op,
+                             const std::string &start, uint64_t max_return)
+{
+  bufferlist in_bl;
+  encode(start, in_bl);
+  encode(max_return, in_bl);
+  op->exec("rbd", "mirror_image_list", in_bl);
+}
+
+int mirror_image_list_finish(bufferlist::const_iterator *it,
+                             std::map<string, string> *mirror_image_ids)
+{
+  try {
+    decode(*mirror_image_ids, *it);
+  } catch (const ceph::buffer::error &err) {
+    return -EBADMSG;
+  }
+  return 0;
+}
+
+int mirror_image_list(librados::IoCtx *ioctx,
+                      const std::string &start, uint64_t max_return,
+                      std::map<std::string, std::string> *mirror_image_ids) {
+  librados::ObjectReadOperation op;
+  mirror_image_list_start(&op, start, max_return);
+
+  bufferlist out_bl;
+  int r = ioctx->operate(RBD_MIRRORING, &op, &out_bl);
+  if (r < 0) {
+    return r;
+  }
+
+  auto bl_it = out_bl.cbegin();
+  return mirror_image_list_finish(&bl_it, mirror_image_ids);
+}
+
+void mirror_image_get_image_id_start(librados::ObjectReadOperation *op,
+                                     const std::string &global_image_id) {
+  bufferlist in_bl;
+  encode(global_image_id, in_bl);
+  op->exec( "rbd", "mirror_image_get_image_id", in_bl);
+}
+
+int mirror_image_get_image_id_finish(bufferlist::const_iterator *it,
+                                     std::string *image_id) {
+  try {
+    decode(*image_id, *it);
+  } catch (const ceph::buffer::error &err) {
+    return -EBADMSG;
+  }
+  return 0;
+}
+
+int mirror_image_get_image_id(librados::IoCtx *ioctx,
+                              const std::string &global_image_id,
+                              std::string *image_id) {
+  librados::ObjectReadOperation op;
+  mirror_image_get_image_id_start(&op, global_image_id);
+
+  bufferlist out_bl;
+  int r = ioctx->operate(RBD_MIRRORING, &op, &out_bl);
+  if (r < 0) {
+    return r;
+  }
+
+  auto it = out_bl.cbegin();
+  return mirror_image_get_image_id_finish(&it, image_id);
+}
+
+int mirror_image_get(librados::IoCtx *ioctx, const std::string &image_id,
+                     cls::rbd::MirrorImage *mirror_image) {
+  librados::ObjectReadOperation op;
+  mirror_image_get_start(&op, image_id);
+
+  bufferlist out_bl;
+  int r = ioctx->operate(RBD_MIRRORING, &op, &out_bl);
+  if (r < 0) {
+    return r;
+  }
+
+  auto iter = out_bl.cbegin();
+  r = mirror_image_get_finish(&iter, mirror_image);
+  if (r < 0) {
+    return r;
+  }
+  return 0;
+}
+
+void mirror_image_get_start(librados::ObjectReadOperation *op,
+                            const std::string &image_id) {
+  bufferlist in_bl;
+  encode(image_id, in_bl);
+
+  op->exec("rbd", "mirror_image_get", in_bl);
+}
+
+int mirror_image_get_finish(bufferlist::const_iterator *iter,
+                            cls::rbd::MirrorImage *mirror_image) {
+  try {
+    decode(*mirror_image, *iter);
+  } catch (const ceph::buffer::error &err) {
+    return -EBADMSG;
+  }
+  return 0;
+}
+
+void mirror_image_set(librados::ObjectWriteOperation *op,
+                      const std::string &image_id,
+                      const cls::rbd::MirrorImage &mirror_image) {
+  bufferlist bl;
+  encode(image_id, bl);
+  encode(mirror_image, bl);
+
+  op->exec("rbd", "mirror_image_set", bl);
+}
+
+int mirror_image_set(librados::IoCtx *ioctx, const std::string &image_id,
+                     const cls::rbd::MirrorImage &mirror_image) {
+  librados::ObjectWriteOperation op;
+  mirror_image_set(&op, image_id, mirror_image);
+
+  int r = ioctx->operate(RBD_MIRRORING, &op);
+  if (r < 0) {
+    return r;
+  }
+  return 0;
+}
+
+void mirror_image_remove(librados::ObjectWriteOperation *op,
+                         const std::string &image_id) {
+  bufferlist bl;
+  encode(image_id, bl);
+
+  op->exec("rbd", "mirror_image_remove", bl);
+}
+
+int mirror_image_remove(librados::IoCtx *ioctx, const std::string &image_id) {
+  librados::ObjectWriteOperation op;
+  mirror_image_remove(&op, image_id);
+
+  int r = ioctx->operate(RBD_MIRRORING, &op);
+  if (r < 0) {
+    return r;
+  }
+  return 0;
+}
+
+int mirror_image_status_set(librados::IoCtx *ioctx,
+                            const std::string &global_image_id,
+                            const cls::rbd::MirrorImageSiteStatus &status) {
+  librados::ObjectWriteOperation op;
+  mirror_image_status_set(&op, global_image_id, status);
+  return ioctx->operate(RBD_MIRRORING, &op);
+}
+
+void mirror_image_status_set(librados::ObjectWriteOperation *op,
+                             const std::string &global_image_id,
+                             const cls::rbd::MirrorImageSiteStatus &status) {
+  bufferlist bl;
+  encode(global_image_id, bl);
+  encode(status, bl);
+  op->exec("rbd", "mirror_image_status_set", bl);
+}
+
+int mirror_image_status_get(librados::IoCtx *ioctx,
+                            const std::string &global_image_id,
+                            cls::rbd::MirrorImageStatus *status) {
+  librados::ObjectReadOperation op;
+  mirror_image_status_get_start(&op, global_image_id);
+
+  bufferlist out_bl;
+  int r = ioctx->operate(RBD_MIRRORING, &op, &out_bl);
+  if (r < 0) {
+    return r;
+  }
+
+  auto iter = out_bl.cbegin();
+  r = mirror_image_status_get_finish(&iter, status);
+  if (r < 0) {
+    return r;
+  }
+  return 0;
+}
+
+void mirror_image_status_get_start(librados::ObjectReadOperation *op,
+                                   const std::string &global_image_id) {
+  bufferlist bl;
+  encode(global_image_id, bl);
+  op->exec("rbd", "mirror_image_status_get", bl);
+}
+
+int mirror_image_status_get_finish(bufferlist::const_iterator *iter,
+                                   cls::rbd::MirrorImageStatus *status) {
+  try {
+    decode(*status, *iter);
+  } catch (const ceph::buffer::error &err) {
+    return -EBADMSG;
+  }
+  return 0;
+}
+
+int mirror_image_status_list(librados::IoCtx *ioctx,
+                             const std::string &start, uint64_t max_return,
+                             std::map<std::string, cls::rbd::MirrorImage> *images,
+                             std::map<std::string, cls::rbd::MirrorImageStatus> *statuses) {
+  librados::ObjectReadOperation op;
+  mirror_image_status_list_start(&op, start, max_return);
+
+  bufferlist out_bl;
+  int r = ioctx->operate(RBD_MIRRORING, &op, &out_bl);
+  if (r < 0) {
+    return r;
+  }
+
+  auto iter = out_bl.cbegin();
+  r = mirror_image_status_list_finish(&iter, images, statuses);
+  if (r < 0) {
+    return r;
+  }
+  return 0;
+}
+
+void mirror_image_status_list_start(librados::ObjectReadOperation *op,
+                                    const std::string &start,
+                                    uint64_t max_return) {
+  bufferlist bl;
+  encode(start, bl);
+  encode(max_return, bl);
+  op->exec("rbd", "mirror_image_status_list", bl);
+}
+
+int mirror_image_status_list_finish(bufferlist::const_iterator *iter,
+                                    std::map<std::string, cls::rbd::MirrorImage> *images,
+                                    std::map<std::string, cls::rbd::MirrorImageStatus> *statuses) {
+  images->clear();
+  statuses->clear();
+  try {
+    decode(*images, *iter);
+    decode(*statuses, *iter);
+  } catch (const ceph::buffer::error &err) {
+    return -EBADMSG;
+  }
+  return 0;
+}
+
+int mirror_image_status_get_summary(
+    librados::IoCtx *ioctx,
+    const std::vector<cls::rbd::MirrorPeer>& mirror_peer_sites,
+    std::map<cls::rbd::MirrorImageStatusState, int32_t> *states) {
+  librados::ObjectReadOperation op;
+  mirror_image_status_get_summary_start(&op, mirror_peer_sites);
+
+  bufferlist out_bl;
+  int r = ioctx->operate(RBD_MIRRORING, &op, &out_bl);
+  if (r < 0) {
+    return r;
+  }
+
+  auto iter = out_bl.cbegin();
+  r = mirror_image_status_get_summary_finish(&iter, states);
+  if (r < 0) {
+    return r;
+  }
+  return 0;
+}
+
+void mirror_image_status_get_summary_start(
+    librados::ObjectReadOperation *op,
+    const std::vector<cls::rbd::MirrorPeer>& mirror_peer_sites) {
+  bufferlist bl;
+  encode(mirror_peer_sites, bl);
+  op->exec("rbd", "mirror_image_status_get_summary", bl);
+}
+
+int mirror_image_status_get_summary_finish(
+    bufferlist::const_iterator *iter,
+    std::map<cls::rbd::MirrorImageStatusState, int32_t> *states) {
+  try {
+    decode(*states, *iter);
+  } catch (const ceph::buffer::error &err) {
+    return -EBADMSG;
+  }
+  return 0;
+}
+
+int mirror_image_status_remove(librados::IoCtx *ioctx,
+                               const std::string &global_image_id) {
+  librados::ObjectWriteOperation op;
+  mirror_image_status_remove(&op, global_image_id);
+  return ioctx->operate(RBD_MIRRORING, &op);
+}
+
+void mirror_image_status_remove(librados::ObjectWriteOperation *op,
+                                const std::string &global_image_id) {
+  bufferlist bl;
+  encode(global_image_id, bl);
+  op->exec("rbd", "mirror_image_status_remove", bl);
+}
+
+int mirror_image_status_remove_down(librados::IoCtx *ioctx) {
+  librados::ObjectWriteOperation op;
+  mirror_image_status_remove_down(&op);
+  return ioctx->operate(RBD_MIRRORING, &op);
+}
+
+void mirror_image_status_remove_down(librados::ObjectWriteOperation *op) {
+  bufferlist bl;
+  op->exec("rbd", "mirror_image_status_remove_down", bl);
+}
+
+int mirror_image_instance_get(librados::IoCtx *ioctx,
+                              const std::string &global_image_id,
+                              entity_inst_t *instance) {
+  librados::ObjectReadOperation op;
+  mirror_image_instance_get_start(&op, global_image_id);
+
+  bufferlist out_bl;
+  int r = ioctx->operate(RBD_MIRRORING, &op, &out_bl);
+  if (r < 0) {
+    return r;
+  }
+
+  auto iter = out_bl.cbegin();
+  r = mirror_image_instance_get_finish(&iter, instance);
+  if (r < 0) {
+    return r;
+  }
+  return 0;
+}
+
+void mirror_image_instance_get_start(librados::ObjectReadOperation *op,
+                                     const std::string &global_image_id) {
+  bufferlist bl;
+  encode(global_image_id, bl);
+  op->exec("rbd", "mirror_image_instance_get", bl);
+}
+
+int mirror_image_instance_get_finish(bufferlist::const_iterator *iter,
+                                     entity_inst_t *instance) {
+  try {
+    decode(*instance, *iter);
+  } catch (const ceph::buffer::error &err) {
+    return -EBADMSG;
+  }
+  return 0;
+}
+
+int mirror_image_instance_list(
+    librados::IoCtx *ioctx, const std::string &start, uint64_t max_return,
+    std::map<std::string, entity_inst_t> *instances) {
+  librados::ObjectReadOperation op;
+  mirror_image_instance_list_start(&op, start, max_return);
+
+  bufferlist out_bl;
+  int r = ioctx->operate(RBD_MIRRORING, &op, &out_bl);
+  if (r < 0) {
+    return r;
+  }
+
+  auto iter = out_bl.cbegin();
+  r = mirror_image_instance_list_finish(&iter, instances);
+  if (r < 0) {
+    return r;
+  }
+  return 0;
+}
+
+void mirror_image_instance_list_start(librados::ObjectReadOperation *op,
+                                      const std::string &start,
+                                      uint64_t max_return) {
+  bufferlist bl;
+  encode(start, bl);
+  encode(max_return, bl);
+  op->exec("rbd", "mirror_image_instance_list", bl);
+}
+
+int mirror_image_instance_list_finish(
+    bufferlist::const_iterator *iter,
+    std::map<std::string, entity_inst_t> *instances) {
+  instances->clear();
+  try {
+    decode(*instances, *iter);
+  } catch (const ceph::buffer::error &err) {
+    return -EBADMSG;
+  }
+  return 0;
+}
+
+void mirror_instances_list_start(librados::ObjectReadOperation *op) {
+  bufferlist bl;
+  op->exec("rbd", "mirror_instances_list", bl);
+}
+
+int mirror_instances_list_finish(bufferlist::const_iterator *iter,
+                                 std::vector<std::string> *instance_ids) {
+  instance_ids->clear();
+  try {
+    decode(*instance_ids, *iter);
+  } catch (const ceph::buffer::error &err) {
+    return -EBADMSG;
+  }
+  return 0;
+}
+
+int mirror_instances_list(librados::IoCtx *ioctx,
+                          std::vector<std::string> *instance_ids) {
+  librados::ObjectReadOperation op;
+  mirror_instances_list_start(&op);
+
+  bufferlist out_bl;
+  int r = ioctx->operate(RBD_MIRROR_LEADER, &op, &out_bl);
+  if (r < 0) {
+    return r;
+  }
+
+  auto iter = out_bl.cbegin();
+  r = mirror_instances_list_finish(&iter, instance_ids);
+  if (r < 0) {
+    return r;
+  }
+  return 0;
+}
+
+void mirror_instances_add(librados::ObjectWriteOperation *op,
+                          const std::string &instance_id) {
+  bufferlist bl;
+  encode(instance_id, bl);
+  op->exec("rbd", "mirror_instances_add", bl);
+}
+
+int mirror_instances_add(librados::IoCtx *ioctx,
+                         const std::string &instance_id) {
+  librados::ObjectWriteOperation op;
+  mirror_instances_add(&op, instance_id);
+  return ioctx->operate(RBD_MIRROR_LEADER, &op);
+}
+
+void mirror_instances_remove(librados::ObjectWriteOperation *op,
+                             const std::string &instance_id) {
+  bufferlist bl;
+  encode(instance_id, bl);
+  op->exec("rbd", "mirror_instances_remove", bl);
+}
+
+int mirror_instances_remove(librados::IoCtx *ioctx,
+                            const std::string &instance_id) {
+  librados::ObjectWriteOperation op;
+  mirror_instances_remove(&op, instance_id);
+  return ioctx->operate(RBD_MIRROR_LEADER, &op);
+}
+
+void mirror_image_map_list_start(librados::ObjectReadOperation *op,
+                                 const std::string &start_after,
+                                 uint64_t max_read) {
+  bufferlist bl;
+  encode(start_after, bl);
+  encode(max_read, bl);
+
+  op->exec("rbd", "mirror_image_map_list", bl);
+}
+
+int mirror_image_map_list_finish(bufferlist::const_iterator *iter,
+                                 std::map<std::string, cls::rbd::MirrorImageMap> *image_mapping) {
+  try {
+    decode(*image_mapping, *iter);
+  } catch (const ceph::buffer::error &err) {
+    return -EBADMSG;
+  }
+  return 0;
+}
+
+int mirror_image_map_list(
+    librados::IoCtx *ioctx, const std::string &start_after,
+    uint64_t max_read,
+    std::map<std::string, cls::rbd::MirrorImageMap> *image_mapping) {
+  librados::ObjectReadOperation op;
+  mirror_image_map_list_start(&op, start_after, max_read);
+
+  bufferlist out_bl;
+  int r = ioctx->operate(RBD_MIRRORING, &op, &out_bl);
+  if (r < 0) {
+    return r;
+  }
+
+  auto iter = out_bl.cbegin();
+  return mirror_image_map_list_finish(&iter, image_mapping);
+}
+
+void mirror_image_map_update(librados::ObjectWriteOperation *op,
+                             const std::string &global_image_id,
+                             const cls::rbd::MirrorImageMap &image_map) {
+  bufferlist bl;
+  encode(global_image_id, bl);
+  encode(image_map, bl);
+
+  op->exec("rbd", "mirror_image_map_update", bl);
+}
+
+void mirror_image_map_remove(librados::ObjectWriteOperation *op,
+                             const std::string &global_image_id) {
+  bufferlist bl;
+  encode(global_image_id, bl);
+
+  op->exec("rbd", "mirror_image_map_remove", bl);
+}
+
+void mirror_image_snapshot_unlink_peer(librados::ObjectWriteOperation *op,
+                                       snapid_t snap_id,
+                                       const std::string &mirror_peer_uuid) {
+  bufferlist bl;
+  encode(snap_id, bl);
+  encode(mirror_peer_uuid, bl);
+
+  op->exec("rbd", "mirror_image_snapshot_unlink_peer", bl);
+}
+
+int mirror_image_snapshot_unlink_peer(librados::IoCtx *ioctx,
+                                      const std::string &oid,
+                                      snapid_t snap_id,
+                                      const std::string &mirror_peer_uuid) {
+  librados::ObjectWriteOperation op;
+  mirror_image_snapshot_unlink_peer(&op, snap_id, mirror_peer_uuid);
+  return ioctx->operate(oid, &op);
+}
+
+void mirror_image_snapshot_set_copy_progress(librados::ObjectWriteOperation *op,
+                                             snapid_t snap_id, bool complete,
+                                             uint64_t copy_progress) {
+  bufferlist bl;
+  encode(snap_id, bl);
+  encode(complete, bl);
+  encode(copy_progress, bl);
+
+  op->exec("rbd", "mirror_image_snapshot_set_copy_progress", bl);
+}
+
+int mirror_image_snapshot_set_copy_progress(librados::IoCtx *ioctx,
+                                            const std::string &oid,
+                                            snapid_t snap_id, bool complete,
+                                            uint64_t copy_progress) {
+  librados::ObjectWriteOperation op;
+  mirror_image_snapshot_set_copy_progress(&op, snap_id, complete,
+                                          copy_progress);
+  return ioctx->operate(oid, &op);
+}
+
+// Groups functions
+int group_dir_list(librados::IoCtx *ioctx, const std::string &oid,
+                   const std::string &start, uint64_t max_return,
+                   map<string, string> *cgs)
+{
+  bufferlist in, out;
+  encode(start, in);
+  encode(max_return, in);
+  int r = ioctx->exec(oid, "rbd", "group_dir_list", in, out);
+  if (r < 0)
+    return r;
+
+  auto iter = out.cbegin();
+  try {
+    decode(*cgs, iter);
+  } catch (const ceph::buffer::error &err) {
+    return -EBADMSG;
+  }
+
+  return 0;
+}
+
+int group_dir_add(librados::IoCtx *ioctx, const std::string &oid,
+                  const std::string &name, const std::string &id)
+{
+  bufferlist in, out;
+  encode(name, in);
+  encode(id, in);
+  return ioctx->exec(oid, "rbd", "group_dir_add", in, out);
+}
+
+int group_dir_rename(librados::IoCtx *ioctx, const std::string &oid,
+                     const std::string &src, const std::string &dest,
+                     const std::string &id)
+{
+  bufferlist in, out;
+  encode(src, in);
+  encode(dest, in);
+  encode(id, in);
+  return ioctx->exec(oid, "rbd", "group_dir_rename", in, out);
+}
+
+int group_dir_remove(librados::IoCtx *ioctx, const std::string &oid,
+                     const std::string &name, const std::string &id)
+{
+  bufferlist in, out;
+  encode(name, in);
+  encode(id, in);
+  return ioctx->exec(oid, "rbd", "group_dir_remove", in, out);
+}
+
+int group_image_remove(librados::IoCtx *ioctx, const std::string &oid,
+                       const cls::rbd::GroupImageSpec &spec)
+{
+  bufferlist bl, bl2;
+  encode(spec, bl);
+
+  return ioctx->exec(oid, "rbd", "group_image_remove", bl, bl2);
+}
+
+int group_image_list(librados::IoCtx *ioctx,
+                     const std::string &oid,
+                     const cls::rbd::GroupImageSpec &start,
+                     uint64_t max_return,
+                     std::vector<cls::rbd::GroupImageStatus> *images)
+{
+  bufferlist bl, bl2;
+  encode(start, bl);
+  encode(max_return, bl);
+
+  int r = ioctx->exec(oid, "rbd", "group_image_list", bl, bl2);
+  if (r < 0)
+    return r;
+
+  auto iter = bl2.cbegin();
+  try {
+    decode(*images, iter);
+  } catch (const ceph::buffer::error &err) {
+    return -EBADMSG;
+  }
+
+  return 0;
+}
+
+int group_image_set(librados::IoCtx *ioctx, const std::string &oid,
+                    const cls::rbd::GroupImageStatus &st)
+{
+  bufferlist bl, bl2;
+  encode(st, bl);
+
+  return ioctx->exec(oid, "rbd", "group_image_set", bl, bl2);
+}
+
+int image_group_add(librados::IoCtx *ioctx, const std::string &oid,
+                    const cls::rbd::GroupSpec &group_spec)
+{
+  bufferlist bl, bl2;
+  encode(group_spec, bl);
+
+  return ioctx->exec(oid, "rbd", "image_group_add", bl, bl2);
+}
+
+int image_group_remove(librados::IoCtx *ioctx, const std::string &oid,
+                       const cls::rbd::GroupSpec &group_spec)
+{
+  bufferlist bl, bl2;
+  encode(group_spec, bl);
+
+  return ioctx->exec(oid, "rbd", "image_group_remove", bl, bl2);
+}
+
+void image_group_get_start(librados::ObjectReadOperation *op)
+{
+  bufferlist in_bl;
+  op->exec("rbd", "image_group_get", in_bl);
+}
+
+int image_group_get_finish(bufferlist::const_iterator *iter,
+                           cls::rbd::GroupSpec *group_spec)
+{
+  try {
+    decode(*group_spec, *iter);
+  } catch (const ceph::buffer::error &err) {
+    return -EBADMSG;
+  }
+  return 0;
+}
+
+int image_group_get(librados::IoCtx *ioctx, const std::string &oid,
+                    cls::rbd::GroupSpec *group_spec)
+{
+  librados::ObjectReadOperation op;
+  image_group_get_start(&op);
+
+  bufferlist out_bl;
+  int r = ioctx->operate(oid, &op, &out_bl);
+  if (r < 0) {
+    return r;
+  }
+
+  auto iter = out_bl.cbegin();
+  return image_group_get_finish(&iter, group_spec);
+}
+
+int group_snap_set(librados::IoCtx *ioctx, const std::string &oid,
+                   const cls::rbd::GroupSnapshot &snapshot)
+{
+  using ceph::encode;
+  bufferlist inbl, outbl;
+  encode(snapshot, inbl);
+  int r = ioctx->exec(oid, "rbd", "group_snap_set", inbl, outbl);
+  return r;
+}
+
+int group_snap_remove(librados::IoCtx *ioctx, const std::string &oid,
+                      const std::string &snap_id)
+{
+  using ceph::encode;
+  bufferlist inbl, outbl;
+  encode(snap_id, inbl);
+  return ioctx->exec(oid, "rbd", "group_snap_remove", inbl, outbl);
+}
+
+int group_snap_get_by_id(librados::IoCtx *ioctx, const std::string &oid,
+                         const std::string &snap_id,
+                         cls::rbd::GroupSnapshot *snapshot)
+{
+  using ceph::encode;
+  using ceph::decode;
+  bufferlist inbl, outbl;
+
+  encode(snap_id, inbl);
+  int r = ioctx->exec(oid, "rbd", "group_snap_get_by_id", inbl, outbl);
+  if (r < 0) {
+    return r;
+  }
+
+  auto iter = outbl.cbegin();
+  try {
+    decode(*snapshot, iter);
+  } catch (const ceph::buffer::error &err) {
+    return -EBADMSG;
+  }
+
+  return 0;
+}
+int group_snap_list(librados::IoCtx *ioctx, const std::string &oid,
+                    const cls::rbd::GroupSnapshot &start,
+                    uint64_t max_return,
+                    std::vector<cls::rbd::GroupSnapshot> *snapshots)
+{
+  using ceph::encode;
+  using ceph::decode;
+  bufferlist inbl, outbl;
+  encode(start, inbl);
+  encode(max_return, inbl);
+
+  int r = ioctx->exec(oid, "rbd", "group_snap_list", inbl, outbl);
+  if (r < 0) {
+    return r;
+  }
+  auto iter = outbl.cbegin();
+  try {
+    decode(*snapshots, iter);
+  } catch (const ceph::buffer::error &err) {
+    return -EBADMSG;
+  }
+
+  return 0;
+}
+
+// rbd_trash functions
+void trash_add(librados::ObjectWriteOperation *op,
+               const std::string &id,
+               const cls::rbd::TrashImageSpec &trash_spec)
+{
+  bufferlist bl;
+  encode(id, bl);
+  encode(trash_spec, bl);
+  op->exec("rbd", "trash_add", bl);
+}
+
+int trash_add(librados::IoCtx *ioctx, const std::string &id,
+              const cls::rbd::TrashImageSpec &trash_spec)
+{
+  librados::ObjectWriteOperation op;
+  trash_add(&op, id, trash_spec);
+
+  return ioctx->operate(RBD_TRASH, &op);
+}
+
+void trash_remove(librados::ObjectWriteOperation *op,
+                  const std::string &id)
+{
+  bufferlist bl;
+  encode(id, bl);
+  op->exec("rbd", "trash_remove", bl);
+}
+
+int trash_remove(librados::IoCtx *ioctx, const std::string &id)
+{
+  librados::ObjectWriteOperation op;
+  trash_remove(&op, id);
+
+  return ioctx->operate(RBD_TRASH, &op);
+}
+
+void trash_list_start(librados::ObjectReadOperation *op,
+                      const std::string &start, uint64_t max_return)
+{
+  bufferlist bl;
+  encode(start, bl);
+  encode(max_return, bl);
+  op->exec("rbd", "trash_list", bl);
+}
+
+int trash_list_finish(bufferlist::const_iterator *it,
+                      map<string, cls::rbd::TrashImageSpec> *entries)
+{
+  ceph_assert(entries);
+
+  try {
+    decode(*entries, *it);
+  } catch (const ceph::buffer::error &err) {
+    return -EBADMSG;
+  }
+
+  return 0;
+}
+
+int trash_list(librados::IoCtx *ioctx,
+               const std::string &start, uint64_t max_return,
+               map<string, cls::rbd::TrashImageSpec> *entries)
+{
+  librados::ObjectReadOperation op;
+  trash_list_start(&op, start, max_return);
+
+  bufferlist out_bl;
+  int r = ioctx->operate(RBD_TRASH, &op, &out_bl);
+  if (r < 0) {
+    return r;
+  }
+
+  auto iter = out_bl.cbegin();
+  return trash_list_finish(&iter, entries);
+}
+
+void trash_get_start(librados::ObjectReadOperation *op,
+                     const std::string &id)
+{
+  bufferlist bl;
+  encode(id, bl);
+  op->exec("rbd", "trash_get", bl);
+}
+
+int trash_get_finish(bufferlist::const_iterator *it,
+                     cls::rbd::TrashImageSpec *trash_spec) {
+  ceph_assert(trash_spec);
+  try {
+    decode(*trash_spec, *it);
+  } catch (const ceph::buffer::error &err) {
+    return -EBADMSG;
+  }
+
+  return 0;
+}
+
+int trash_get(librados::IoCtx *ioctx, const std::string &id,
+              cls::rbd::TrashImageSpec *trash_spec)
+{
+  librados::ObjectReadOperation op;
+  trash_get_start(&op, id);
+
+  bufferlist out_bl;
+  int r = ioctx->operate(RBD_TRASH, &op, &out_bl);
+  if (r < 0) {
+    return r;
+  }
+
+  auto it = out_bl.cbegin();
+  return trash_get_finish(&it, trash_spec);
+}
+
+void trash_state_set(librados::ObjectWriteOperation *op,
+                     const std::string &id,
+                     const cls::rbd::TrashImageState &trash_state,
+                     const cls::rbd::TrashImageState &expect_state)
+{
+  bufferlist bl;
+  encode(id, bl);
+  encode(trash_state, bl);
+  encode(expect_state, bl);
+  op->exec("rbd", "trash_state_set", bl);
+}
+
+int trash_state_set(librados::IoCtx *ioctx, const std::string &id,
+                    const cls::rbd::TrashImageState &trash_state,
+                    const cls::rbd::TrashImageState &expect_state)
+{
+  librados::ObjectWriteOperation op;
+  trash_state_set(&op, id, trash_state, expect_state);
+
+  return ioctx->operate(RBD_TRASH, &op);
+}
+
+void namespace_add(librados::ObjectWriteOperation *op,
+                   const std::string &name)
+{
+  bufferlist bl;
+  encode(name, bl);
+  op->exec("rbd", "namespace_add", bl);
+}
+
+int namespace_add(librados::IoCtx *ioctx, const std::string &name)
+{
+  librados::ObjectWriteOperation op;
+  namespace_add(&op, name);
+
+  return ioctx->operate(RBD_NAMESPACE, &op);
+}
+
+void namespace_remove(librados::ObjectWriteOperation *op,
+                      const std::string &name)
+{
+  bufferlist bl;
+  encode(name, bl);
+  op->exec("rbd", "namespace_remove", bl);
+}
+
+int namespace_remove(librados::IoCtx *ioctx, const std::string &name)
+{
+  librados::ObjectWriteOperation op;
+  namespace_remove(&op, name);
+
+  return ioctx->operate(RBD_NAMESPACE, &op);
+}
+
+void namespace_list_start(librados::ObjectReadOperation *op,
+                          const std::string &start, uint64_t max_return)
+{
+  bufferlist bl;
+  encode(start, bl);
+  encode(max_return, bl);
+  op->exec("rbd", "namespace_list", bl);
+}
+
+int namespace_list_finish(bufferlist::const_iterator *it,
+                          std::list<std::string> *entries)
+{
+  ceph_assert(entries);
+
+  try {
+    decode(*entries, *it);
+  } catch (const ceph::buffer::error &err) {
+    return -EBADMSG;
+  }
+
+  return 0;
+}
+
+int namespace_list(librados::IoCtx *ioctx,
+                   const std::string &start, uint64_t max_return,
+                   std::list<std::string> *entries)
+{
+  librados::ObjectReadOperation op;
+  namespace_list_start(&op, start, max_return);
+
+  bufferlist out_bl;
+  int r = ioctx->operate(RBD_NAMESPACE, &op, &out_bl);
+  if (r < 0) {
+    return r;
+  }
+
+  auto iter = out_bl.cbegin();
+  return namespace_list_finish(&iter, entries);
+}
+
+void sparsify(librados::ObjectWriteOperation *op, size_t sparse_size,
+              bool remove_empty)
+{
+  bufferlist bl;
+  encode(sparse_size, bl);
+  encode(remove_empty, bl);
+  op->exec("rbd", "sparsify", bl);
+}
+
+int sparsify(librados::IoCtx *ioctx, const std::string &oid, size_t sparse_size,
+             bool remove_empty)
+{
+  librados::ObjectWriteOperation op;
+  sparsify(&op, sparse_size, remove_empty);
+
+  return ioctx->operate(oid, &op);
+}
+
+} // namespace cls_client
+} // namespace librbd
diff --git a/src/cls/rbd/cls_rbd_client.h b/src/cls/rbd/cls_rbd_client.h
new file mode 100644
index 000000000..9bb5a41d8
--- /dev/null
+++ b/src/cls/rbd/cls_rbd_client.h
@@ -0,0 +1,667 @@
+// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
+// vim: ts=8 sw=2 smarttab
+
+#ifndef CEPH_LIBRBD_CLS_RBD_CLIENT_H
+#define CEPH_LIBRBD_CLS_RBD_CLIENT_H
+
+#include "cls/lock/cls_lock_types.h"
+#include "cls/rbd/cls_rbd_types.h"
+#include "common/snap_types.h"
+#include "include/types.h"
+#include "include/rados/librados_fwd.hpp"
+
+class Context;
+namespace ceph { template <uint8_t> class BitVector; }
+namespace neorados { struct WriteOp; }
+
+namespace librbd {
+namespace cls_client {
+
+// low-level interface (mainly for testing)
+void create_image(librados::ObjectWriteOperation *op, uint64_t size,
+                  uint8_t order, uint64_t features,
+                  const std::string &object_prefix, int64_t data_pool_id);
+int create_image(librados::IoCtx *ioctx, const std::string &oid,
+                 uint64_t size, uint8_t order, uint64_t features,
+                 const std::string &object_prefix, int64_t data_pool_id);
+
+void get_features_start(librados::ObjectReadOperation *op, bool read_only);
+int get_features_finish(ceph::buffer::list::const_iterator *it, uint64_t *features,
+                        uint64_t *incompatible_features);
+int get_features(librados::IoCtx *ioctx, const std::string &oid,
+                 bool read_only, uint64_t *features,
+                 uint64_t *incompatible_features);
+void set_features(librados::ObjectWriteOperation *op, uint64_t features,
+                  uint64_t mask);
+int set_features(librados::IoCtx *ioctx, const std::string &oid,
+                 uint64_t features, uint64_t mask);
+
+void get_object_prefix_start(librados::ObjectReadOperation *op);
+int get_object_prefix_finish(ceph::buffer::list::const_iterator *it,
+                             std::string *object_prefix);
+int get_object_prefix(librados::IoCtx *ioctx, const std::string &oid,
+                      std::string *object_prefix);
+
+void get_data_pool_start(librados::ObjectReadOperation *op);
+int get_data_pool_finish(ceph::buffer::list::const_iterator *it, int64_t *data_pool_id);
+int get_data_pool(librados::IoCtx *ioctx, const std::string &oid,
+                  int64_t *data_pool_id);
+
+void get_size_start(librados::ObjectReadOperation *op, snapid_t snap_id);
+int get_size_finish(ceph::buffer::list::const_iterator *it, uint64_t *size,
+                    uint8_t *order);
+int get_size(librados::IoCtx *ioctx, const std::string &oid,
+             snapid_t snap_id, uint64_t *size, uint8_t *order);
+int set_size(librados::IoCtx *ioctx, const std::string &oid,
+             uint64_t size);
+void set_size(librados::ObjectWriteOperation *op, uint64_t size);
+
+void get_flags_start(librados::ObjectReadOperation *op, snapid_t snap_id);
+int get_flags_finish(ceph::buffer::list::const_iterator *it, uint64_t *flags);
+int get_flags(librados::IoCtx *ioctx, const std::string &oid,
+              snapid_t snap_id, uint64_t *flags);
+
+void set_flags(librados::ObjectWriteOperation *op, snapid_t snap_id,
+               uint64_t flags, uint64_t mask);
+
+void op_features_get_start(librados::ObjectReadOperation *op);
+int op_features_get_finish(ceph::buffer::list::const_iterator *it,
+                           uint64_t *op_features);
+int op_features_get(librados::IoCtx *ioctx, const std::string &oid,
+                    uint64_t *op_features);
+void op_features_set(librados::ObjectWriteOperation *op,
+                     uint64_t op_features, uint64_t mask);
+int op_features_set(librados::IoCtx *ioctx, const std::string &oid,
+                    uint64_t op_features, uint64_t mask);
+
+// NOTE: deprecate v1 parent APIs after mimic EOLed
+void get_parent_start(librados::ObjectReadOperation *op, snapid_t snap_id);
+int get_parent_finish(ceph::buffer::list::const_iterator *it,
+                      cls::rbd::ParentImageSpec *pspec,
+                      uint64_t *parent_overlap);
+int get_parent(librados::IoCtx *ioctx, const std::string &oid,
+               snapid_t snap_id, cls::rbd::ParentImageSpec *pspec,
+               uint64_t *parent_overlap);
+int set_parent(librados::IoCtx *ioctx, const std::string &oid,
+               const cls::rbd::ParentImageSpec &pspec, uint64_t parent_overlap);
+void set_parent(librados::ObjectWriteOperation *op,
+                const cls::rbd::ParentImageSpec &pspec,
+                uint64_t parent_overlap);
+int remove_parent(librados::IoCtx *ioctx, const std::string &oid);
+void remove_parent(librados::ObjectWriteOperation *op);
+
+// v2 parent APIs
+void parent_get_start(librados::ObjectReadOperation* op);
+int parent_get_finish(ceph::buffer::list::const_iterator* it,
+                      cls::rbd::ParentImageSpec* parent_image_spec);
+int parent_get(librados::IoCtx* ioctx, const std::string &oid,
+               cls::rbd::ParentImageSpec* parent_image_spec);
+
+void parent_overlap_get_start(librados::ObjectReadOperation* op,
+                              snapid_t snap_id);
+int parent_overlap_get_finish(ceph::buffer::list::const_iterator* it,
+                              std::optional<uint64_t>* parent_overlap);
+int parent_overlap_get(librados::IoCtx* ioctx, const std::string &oid,
+                       snapid_t snap_id,
+                       std::optional<uint64_t>* parent_overlap);
+
+void parent_attach(librados::ObjectWriteOperation* op,
+                   const cls::rbd::ParentImageSpec& parent_image_spec,
+                   uint64_t parent_overlap, bool reattach);
+int parent_attach(librados::IoCtx *ioctx, const std::string &oid,
+                  const cls::rbd::ParentImageSpec& parent_image_spec,
+                  uint64_t parent_overlap, bool reattach);
+
+void parent_detach(librados::ObjectWriteOperation* op);
+int parent_detach(librados::IoCtx *ioctx, const std::string &oid);
+
+int add_child(librados::IoCtx *ioctx, const std::string &oid,
+              const cls::rbd::ParentImageSpec &pspec,
+              const std::string &c_imageid);
+void add_child(librados::ObjectWriteOperation *op,
+               const cls::rbd::ParentImageSpec& pspec,
+               const std::string &c_imageid);
+void remove_child(librados::ObjectWriteOperation *op,
+                  const cls::rbd::ParentImageSpec &pspec,
+                  const std::string &c_imageid);
+int remove_child(librados::IoCtx *ioctx, const std::string &oid,
+                 const cls::rbd::ParentImageSpec &pspec,
+                 const std::string &c_imageid);
+void get_children_start(librados::ObjectReadOperation *op,
+                        const cls::rbd::ParentImageSpec &pspec);
+int get_children_finish(ceph::buffer::list::const_iterator *it,
+                        std::set<std::string> *children);
+int get_children(librados::IoCtx *ioctx, const std::string &oid,
+                 const cls::rbd::ParentImageSpec& pspec, std::set<std::string>& children);
+
+void snapshot_get_start(librados::ObjectReadOperation* op,
+                        snapid_t snap_id);
+int snapshot_get_finish(ceph::buffer::list::const_iterator* it,
+                        cls::rbd::SnapshotInfo* snap_info);
+int snapshot_get(librados::IoCtx *ioctx, const std::string &oid,
+                 snapid_t snap_id, cls::rbd::SnapshotInfo* snap_info);
+
+void snapshot_add(librados::ObjectWriteOperation *op, snapid_t snap_id,
+                  const std::string &snap_name,
+                  const cls::rbd::SnapshotNamespace &snap_namespace);
+void snapshot_remove(librados::ObjectWriteOperation *op, snapid_t snap_id);
+void snapshot_rename(librados::ObjectWriteOperation *op,
+                     snapid_t src_snap_id,
+                     const std::string &dst_name);
+void snapshot_trash_add(librados::ObjectWriteOperation *op,
+                        snapid_t snap_id);
+
+void get_snapcontext_start(librados::ObjectReadOperation *op);
+int get_snapcontext_finish(ceph::buffer::list::const_iterator *it,
+                           ::SnapContext *snapc);
+int get_snapcontext(librados::IoCtx *ioctx, const std::string &oid,
+                    ::SnapContext *snapc);
+
+/// NOTE: remove after Luminous is retired
+void get_snapshot_name_start(librados::ObjectReadOperation *op,
+                             snapid_t snap_id);
+int get_snapshot_name_finish(ceph::buffer::list::const_iterator *it,
+                             std::string *name);
+int get_snapshot_name(librados::IoCtx *ioctx, const std::string &oid,
+                      snapid_t snap_id, std::string *name);
+
+/// NOTE: remove after Luminous is retired
+void get_snapshot_timestamp_start(librados::ObjectReadOperation *op,
+                                  snapid_t snap_id);
+int get_snapshot_timestamp_finish(ceph::buffer::list::const_iterator *it,
+                                  utime_t *timestamp);
+int get_snapshot_timestamp(librados::IoCtx *ioctx, const std::string &oid,
+                           snapid_t snap_id, utime_t *timestamp);
+
+void get_all_features_start(librados::ObjectReadOperation *op);
+int get_all_features_finish(ceph::buffer::list::const_iterator *it,
+                            uint64_t *all_features);
+int get_all_features(librados::IoCtx *ioctx, const std::string &oid,
+                     uint64_t *all_features);
+
+/// NOTE: remove protection after clone v1 is retired
+void get_protection_status_start(librados::ObjectReadOperation *op,
+                                 snapid_t snap_id);
+int get_protection_status_finish(ceph::buffer::list::const_iterator *it,
+                                 uint8_t *protection_status);
+int get_protection_status(librados::IoCtx *ioctx, const std::string &oid,
+                          snapid_t snap_id, uint8_t *protection_status);
+
+int set_protection_status(librados::IoCtx *ioctx, const std::string &oid,
+                          snapid_t snap_id, uint8_t protection_status);
+void set_protection_status(librados::ObjectWriteOperation *op,
+                           snapid_t snap_id, uint8_t protection_status);
+
+void snapshot_get_limit_start(librados::ObjectReadOperation *op);
+int snapshot_get_limit_finish(ceph::buffer::list::const_iterator *it, uint64_t *limit);
+int snapshot_get_limit(librados::IoCtx *ioctx, const std::string &oid,
+                       uint64_t *limit);
+void snapshot_set_limit(librados::ObjectWriteOperation *op,
+                        uint64_t limit);
+
+void get_stripe_unit_count_start(librados::ObjectReadOperation *op);
+int get_stripe_unit_count_finish(ceph::buffer::list::const_iterator *it,
+                                 uint64_t *stripe_unit,
+                                 uint64_t *stripe_count);
+int get_stripe_unit_count(librados::IoCtx *ioctx, const std::string &oid,
+                          uint64_t *stripe_unit, uint64_t *stripe_count);
+
+void set_stripe_unit_count(librados::ObjectWriteOperation *op,
+                           uint64_t stripe_unit, uint64_t stripe_count);
+int set_stripe_unit_count(librados::IoCtx *ioctx, const std::string &oid,
+                          uint64_t stripe_unit, uint64_t stripe_count);
+
+void get_create_timestamp_start(librados::ObjectReadOperation *op);
+int get_create_timestamp_finish(ceph::buffer::list::const_iterator *it,
+                                utime_t *timestamp);
+int get_create_timestamp(librados::IoCtx *ioctx, const std::string &oid,
+                         utime_t *timestamp);
+
+void get_access_timestamp_start(librados::ObjectReadOperation *op);
+int get_access_timestamp_finish(ceph::buffer::list::const_iterator *it,
+                                utime_t *timestamp);
+int get_access_timestamp(librados::IoCtx *ioctx, const std::string &oid,
+                         utime_t *timestamp);
+
+void set_access_timestamp(librados::ObjectWriteOperation *op);
+int set_access_timestamp(librados::IoCtx *ioctx, const std::string &oid);
+
+void get_modify_timestamp_start(librados::ObjectReadOperation *op);
+int get_modify_timestamp_finish(ceph::buffer::list::const_iterator *it,
+                                utime_t *timestamp);
+int get_modify_timestamp(librados::IoCtx *ioctx, const std::string &oid,
+                         utime_t *timestamp);
+
+void set_modify_timestamp(librados::ObjectWriteOperation *op);
+int set_modify_timestamp(librados::IoCtx *ioctx, const std::string &oid);
+
+int metadata_list(librados::IoCtx *ioctx, const std::string &oid,
+                  const std::string &start, uint64_t max_return,
+                  std::map<std::string, ceph::buffer::list> *pairs);
+void metadata_list_start(librados::ObjectReadOperation *op,
+                         const std::string &start, uint64_t max_return);
+int metadata_list_finish(ceph::buffer::list::const_iterator *it,
+                         std::map<std::string, ceph::buffer::list> *pairs);
+void metadata_set(librados::ObjectWriteOperation *op,
+                  const std::map<std::string, ceph::buffer::list> &data);
+int metadata_set(librados::IoCtx *ioctx, const std::string &oid,
+                 const std::map<std::string, ceph::buffer::list> &data);
+void metadata_remove(librados::ObjectWriteOperation *op,
+                     const std::string &key);
+int metadata_remove(librados::IoCtx *ioctx, const std::string &oid,
+                    const std::string &key);
+void metadata_get_start(librados::ObjectReadOperation* op,
+                 const std::string &key);
+int metadata_get_finish(ceph::buffer::list::const_iterator *it,
+                        std::string* value);
+int metadata_get(librados::IoCtx *ioctx, const std::string &oid,
+                 const std::string &key, std::string *v);
+
+void child_attach(librados::ObjectWriteOperation *op, snapid_t snap_id,
+                  const cls::rbd::ChildImageSpec& child_image);
+int child_attach(librados::IoCtx *ioctx, const std::string &oid,
+                 snapid_t snap_id,
+                 const cls::rbd::ChildImageSpec& child_image);
+void child_detach(librados::ObjectWriteOperation *op, snapid_t snap_id,
+                  const cls::rbd::ChildImageSpec& child_image);
+int child_detach(librados::IoCtx *ioctx, const std::string &oid,
+                 snapid_t snap_id,
+                 const cls::rbd::ChildImageSpec& child_image);
+void children_list_start(librados::ObjectReadOperation *op,
+                         snapid_t snap_id);
+int children_list_finish(ceph::buffer::list::const_iterator *it,
+                         cls::rbd::ChildImageSpecs *child_images);
+int children_list(librados::IoCtx *ioctx, const std::string &oid,
+                  snapid_t snap_id,
+                  cls::rbd::ChildImageSpecs *child_images);
+int migration_set(librados::IoCtx *ioctx, const std::string &oid,
+                  const cls::rbd::MigrationSpec &migration_spec);
+void migration_set(librados::ObjectWriteOperation *op,
+                   const cls::rbd::MigrationSpec &migration_spec);
+int migration_set_state(librados::IoCtx *ioctx, const std::string &oid,
+                        cls::rbd::MigrationState state,
+                        const std::string &description);
+void migration_set_state(librados::ObjectWriteOperation *op,
+                         cls::rbd::MigrationState state,
+                         const std::string &description);
+void migration_get_start(librados::ObjectReadOperation *op);
+int migration_get_finish(ceph::buffer::list::const_iterator *it,
+                         cls::rbd::MigrationSpec *migration_spec);
+int migration_get(librados::IoCtx *ioctx, const std::string &oid,
+                  cls::rbd::MigrationSpec *migration_spec);
+int migration_remove(librados::IoCtx *ioctx, const std::string &oid);
+void migration_remove(librados::ObjectWriteOperation *op);
+
+// operations on rbd_id objects
+void get_id_start(librados::ObjectReadOperation *op);
+int get_id_finish(ceph::buffer::list::const_iterator *it, std::string *id);
+int get_id(librados::IoCtx *ioctx, const std::string &oid, std::string *id);
+
+void set_id(librados::ObjectWriteOperation *op, const std::string &id);
+int set_id(librados::IoCtx *ioctx, const std::string &oid, const std::string &id);
+
+// operations on rbd_directory objects
+int dir_get_id(librados::IoCtx *ioctx, const std::string &oid,
+               const std::string &name, std::string *id);
+void dir_get_id_start(librados::ObjectReadOperation *op,
+                      const std::string &image_name);
+int dir_get_id_finish(ceph::buffer::list::const_iterator *iter, std::string *image_id);
+void dir_get_name_start(librados::ObjectReadOperation *op,
+                        const std::string &id);
+int dir_get_name_finish(ceph::buffer::list::const_iterator *it, std::string *name);
+int dir_get_name(librados::IoCtx *ioctx, const std::string &oid,
+                 const std::string &id, std::string *name);
+void dir_list_start(librados::ObjectReadOperation *op,
+                    const std::string &start, uint64_t max_return);
+int dir_list_finish(ceph::buffer::list::const_iterator *it, std::map<std::string, std::string> *images);
+int dir_list(librados::IoCtx *ioctx, const std::string &oid,
+             const std::string &start, uint64_t max_return,
+             std::map<std::string, std::string> *images);
+void dir_add_image(librados::ObjectWriteOperation *op,
+                   const std::string &name, const std::string &id);
+int dir_add_image(librados::IoCtx *ioctx, const std::string &oid,
+                  const std::string &name, const std::string &id);
+int dir_remove_image(librados::IoCtx *ioctx, const std::string &oid,
+                     const std::string &name, const std::string &id);
+void dir_remove_image(librados::ObjectWriteOperation *op,
+                      const std::string &name, const std::string &id);
+// atomic remove and add
+void dir_rename_image(librados::ObjectWriteOperation *op,
+                      const std::string &src, const std::string &dest,
+                      const std::string &id);
+void dir_state_assert(librados::ObjectOperation *op,
+                      cls::rbd::DirectoryState directory_state);
+int dir_state_assert(librados::IoCtx *ioctx, const std::string &oid,
+                     cls::rbd::DirectoryState directory_state);
+void dir_state_set(librados::ObjectWriteOperation *op,
+                   cls::rbd::DirectoryState directory_state);
+int dir_state_set(librados::IoCtx *ioctx, const std::string &oid,
+                  cls::rbd::DirectoryState directory_state);
+
+// operations on the rbd_object_map.$image_id object
+void object_map_load_start(librados::ObjectReadOperation *op);
+int object_map_load_finish(ceph::buffer::list::const_iterator *it,
+                           ceph::BitVector<2> *object_map);
+int object_map_load(librados::IoCtx *ioctx, const std::string &oid,
+                    ceph::BitVector<2> *object_map);
+void object_map_save(librados::ObjectWriteOperation *rados_op,
+                     const ceph::BitVector<2> &object_map);
+void object_map_resize(librados::ObjectWriteOperation *rados_op,
+                       uint64_t object_count, uint8_t default_state);
+void object_map_update(librados::ObjectWriteOperation *rados_op,
+                       uint64_t start_object_no, uint64_t end_object_no,
+                       uint8_t new_object_state,
+                       const boost::optional<uint8_t> &current_object_state);
+void object_map_snap_add(librados::ObjectWriteOperation *rados_op);
+void object_map_snap_remove(librados::ObjectWriteOperation *rados_op,
+                            const ceph::BitVector<2> &object_map);
+
+// class operations on the old format, kept for
+// backwards compatibility
+void old_snapshot_add(librados::ObjectWriteOperation *rados_op,
+                      snapid_t snap_id, const std::string &snap_name);
+void old_snapshot_remove(librados::ObjectWriteOperation *rados_op,
+                         const std::string &snap_name);
+void old_snapshot_rename(librados::ObjectWriteOperation *rados_op,
+                         snapid_t src_snap_id, const std::string &dst_name);
+
+void old_snapshot_list_start(librados::ObjectReadOperation *op);
+int old_snapshot_list_finish(ceph::buffer::list::const_iterator *it,
+                             std::vector<std::string> *names,
+                             std::vector<uint64_t> *sizes,
+                             ::SnapContext *snapc);
+int old_snapshot_list(librados::IoCtx *ioctx, const std::string &oid,
+                      std::vector<std::string> *names,
+                      std::vector<uint64_t> *sizes,
+                      ::SnapContext *snapc);
+
+// operations on the rbd_mirroring object
+void mirror_uuid_get_start(librados::ObjectReadOperation *op);
+int mirror_uuid_get_finish(ceph::buffer::list::const_iterator *it,
+                           std::string *uuid);
+int mirror_uuid_get(librados::IoCtx *ioctx, std::string *uuid);
+int mirror_uuid_set(librados::IoCtx *ioctx, const std::string &uuid);
+void mirror_mode_get_start(librados::ObjectReadOperation *op);
+int mirror_mode_get_finish(ceph::buffer::list::const_iterator *it,
+                           cls::rbd::MirrorMode *mirror_mode);
+int mirror_mode_get(librados::IoCtx *ioctx,
+                    cls::rbd::MirrorMode *mirror_mode);
+int mirror_mode_set(librados::IoCtx *ioctx,
+                    cls::rbd::MirrorMode mirror_mode);
+
+int mirror_peer_ping(librados::IoCtx *ioctx,
+                     const std::string& site_name,
+                     const std::string& fsid);
+void mirror_peer_ping(librados::ObjectWriteOperation *op,
+                      const std::string& site_name,
+                      const std::string& fsid);
+void mirror_peer_list_start(librados::ObjectReadOperation *op);
+int mirror_peer_list_finish(ceph::buffer::list::const_iterator *it,
+                            std::vector<cls::rbd::MirrorPeer> *peers);
+int mirror_peer_list(librados::IoCtx *ioctx,
+                     std::vector<cls::rbd::MirrorPeer> *peers);
+int mirror_peer_add(librados::IoCtx *ioctx,
+                    const cls::rbd::MirrorPeer& mirror_peer);
+void mirror_peer_add(librados::ObjectWriteOperation *op,
+                     const cls::rbd::MirrorPeer& mirror_peer);
+int mirror_peer_remove(librados::IoCtx *ioctx,
+                       const std::string &uuid);
+int mirror_peer_set_client(librados::IoCtx *ioctx,
+                           const std::string &uuid,
+                           const std::string &client_name);
+int mirror_peer_set_cluster(librados::IoCtx *ioctx,
+                            const std::string &uuid,
+                            const std::string &cluster_name);
+int mirror_peer_set_direction(
+    librados::IoCtx *ioctx, const std::string &uuid,
+    cls::rbd::MirrorPeerDirection mirror_peer_direction);
+
+void mirror_image_list_start(librados::ObjectReadOperation *op,
+                             const std::string &start, uint64_t max_return);
+int mirror_image_list_finish(ceph::buffer::list::const_iterator *it,
+                             std::map<std::string, std::string> *mirror_image_ids);
+int mirror_image_list(librados::IoCtx *ioctx,
+                      const std::string &start, uint64_t max_return,
+                      std::map<std::string, std::string> *mirror_image_ids);
+void mirror_image_get_image_id_start(librados::ObjectReadOperation *op,
+                                     const std::string &global_image_id);
+int mirror_image_get_image_id_finish(ceph::buffer::list::const_iterator *it,
+                                     std::string *image_id);
+int mirror_image_get_image_id(librados::IoCtx *ioctx,
+                              const std::string &global_image_id,
+                              std::string *image_id);
+int mirror_image_get(librados::IoCtx *ioctx, const std::string &image_id,
+                     cls::rbd::MirrorImage *mirror_image);
+void mirror_image_get_start(librados::ObjectReadOperation *op,
+                            const std::string &image_id);
+int mirror_image_get_finish(ceph::buffer::list::const_iterator *iter,
+                            cls::rbd::MirrorImage *mirror_image);
+void mirror_image_set(librados::ObjectWriteOperation *op,
+                      const std::string &image_id,
+                      const cls::rbd::MirrorImage &mirror_image);
+int mirror_image_set(librados::IoCtx *ioctx, const std::string &image_id,
+                     const cls::rbd::MirrorImage &mirror_image);
+void mirror_image_remove(librados::ObjectWriteOperation *op,
+                         const std::string &image_id);
+int mirror_image_remove(librados::IoCtx *ioctx,
+                        const std::string &image_id);
+int mirror_image_status_set(librados::IoCtx *ioctx,
+                            const std::string &global_image_id,
+                            const cls::rbd::MirrorImageSiteStatus &status);
+void mirror_image_status_set(librados::ObjectWriteOperation *op,
+                             const std::string &global_image_id,
+                             const cls::rbd::MirrorImageSiteStatus &status);
+int mirror_image_status_get(librados::IoCtx *ioctx,
+                            const std::string &global_image_id,
+                            cls::rbd::MirrorImageStatus *status);
+void mirror_image_status_get_start(librados::ObjectReadOperation *op,
+                                   const std::string &global_image_id);
+int mirror_image_status_get_finish(ceph::buffer::list::const_iterator *iter,
+                                   cls::rbd::MirrorImageStatus *status);
+int mirror_image_status_list(librados::IoCtx *ioctx,
+                             const std::string &start, uint64_t max_return,
+                             std::map<std::string, cls::rbd::MirrorImage> *images,
+                             std::map<std::string, cls::rbd::MirrorImageStatus> *statuses);
+void mirror_image_status_list_start(librados::ObjectReadOperation *op,
+                                    const std::string &start,
+                                    uint64_t max_return);
+int mirror_image_status_list_finish(ceph::buffer::list::const_iterator *iter,
+                                    std::map<std::string, cls::rbd::MirrorImage> *images,
+                                    std::map<std::string, cls::rbd::MirrorImageStatus> *statuses);
+int mirror_image_status_get_summary(
+    librados::IoCtx *ioctx,
+    const std::vector<cls::rbd::MirrorPeer>& mirror_peer_sites,
+    std::map<cls::rbd::MirrorImageStatusState, int32_t> *states);
+void mirror_image_status_get_summary_start(
+    librados::ObjectReadOperation *op,
+    const std::vector<cls::rbd::MirrorPeer>& mirror_peer_sites);
+int mirror_image_status_get_summary_finish(
+    ceph::buffer::list::const_iterator *iter,
+    std::map<cls::rbd::MirrorImageStatusState, int32_t> *states);
+int mirror_image_status_remove(librados::IoCtx *ioctx,
+                               const std::string &global_image_id);
+void mirror_image_status_remove(librados::ObjectWriteOperation *op,
+                                const std::string &global_image_id);
+int mirror_image_status_remove_down(librados::IoCtx *ioctx);
+void mirror_image_status_remove_down(librados::ObjectWriteOperation *op);
+
+int mirror_image_instance_get(librados::IoCtx *ioctx,
+                              const std::string &global_image_id,
+                              entity_inst_t *instance);
+void mirror_image_instance_get_start(librados::ObjectReadOperation *op,
+                                     const std::string &global_image_id);
+int mirror_image_instance_get_finish(ceph::buffer::list::const_iterator *iter,
+                                     entity_inst_t *instance);
+int mirror_image_instance_list(librados::IoCtx *ioctx,
+                               const std::string &start, uint64_t max_return,
+                               std::map<std::string, entity_inst_t> *instances);
+void mirror_image_instance_list_start(librados::ObjectReadOperation *op,
+                                      const std::string &start,
+                                      uint64_t max_return);
+int mirror_image_instance_list_finish(ceph::buffer::list::const_iterator *iter,
+                                      std::map<std::string, entity_inst_t> *instances);
+
+void mirror_instances_list_start(librados::ObjectReadOperation *op);
+int mirror_instances_list_finish(ceph::buffer::list::const_iterator *iter,
+                                 std::vector<std::string> *instance_ids);
+int mirror_instances_list(librados::IoCtx *ioctx,
+                          std::vector<std::string> *instance_ids);
+void mirror_instances_add(librados::ObjectWriteOperation *op,
+                          const std::string &instance_id);
+int mirror_instances_add(librados::IoCtx *ioctx,
+                         const std::string &instance_id);
+void mirror_instances_remove(librados::ObjectWriteOperation *op,
+                             const std::string &instance_id);
+int mirror_instances_remove(librados::IoCtx *ioctx,
+                            const std::string &instance_id);
+
+// image mapping related routines
+void mirror_image_map_list_start(librados::ObjectReadOperation *op,
+                                 const std::string &start_after,
+                                 uint64_t max_read);
+int mirror_image_map_list_finish(ceph::buffer::list::const_iterator *iter,
+                                 std::map<std::string, cls::rbd::MirrorImageMap> *image_mapping);
+int mirror_image_map_list(librados::IoCtx *ioctx,
+                          const std::string &start_after, uint64_t max_read,
+                          std::map<std::string, cls::rbd::MirrorImageMap> *image_mapping);
+void mirror_image_map_update(librados::ObjectWriteOperation *op,
+                             const std::string &global_image_id,
+                             const cls::rbd::MirrorImageMap &image_map);
+void mirror_image_map_remove(librados::ObjectWriteOperation *op,
+                             const std::string &global_image_id);
+
+void mirror_image_snapshot_unlink_peer(librados::ObjectWriteOperation *op,
+                                       snapid_t snap_id,
+                                       const std::string &mirror_peer_uuid);
+int mirror_image_snapshot_unlink_peer(librados::IoCtx *ioctx,
+                                      const std::string &oid,
+                                      snapid_t snap_id,
+                                      const std::string &mirror_peer_uuid);
+void mirror_image_snapshot_set_copy_progress(librados::ObjectWriteOperation *op,
+                                             snapid_t snap_id, bool complete,
+                                             uint64_t copy_progress);
+int mirror_image_snapshot_set_copy_progress(librados::IoCtx *ioctx,
+                                            const std::string &oid,
+                                            snapid_t snap_id, bool complete,
+                                            uint64_t copy_progress);
+
+// Groups functions
+int group_dir_list(librados::IoCtx *ioctx, const std::string &oid,
+                   const std::string &start, uint64_t max_return,
+                   std::map<std::string, std::string> *groups);
+int group_dir_add(librados::IoCtx *ioctx, const std::string &oid,
+                  const std::string &name, const std::string &id);
+int group_dir_rename(librados::IoCtx *ioctx, const std::string &oid,
+                     const std::string &src, const std::string &dest,
+                     const std::string &id);
+int group_dir_remove(librados::IoCtx *ioctx, const std::string &oid,
+                     const std::string &name, const std::string &id);
+int group_image_remove(librados::IoCtx *ioctx, const std::string &oid,
+                       const cls::rbd::GroupImageSpec &spec);
+int group_image_list(librados::IoCtx *ioctx, const std::string &oid,
+                     const cls::rbd::GroupImageSpec &start,
+                     uint64_t max_return,
+                     std::vector<cls::rbd::GroupImageStatus> *images);
+int group_image_set(librados::IoCtx *ioctx, const std::string &oid,
+                    const cls::rbd::GroupImageStatus &st);
+int image_group_add(librados::IoCtx *ioctx, const std::string &oid,
+                    const cls::rbd::GroupSpec &group_spec);
+int image_group_remove(librados::IoCtx *ioctx, const std::string &oid,
+                       const cls::rbd::GroupSpec &group_spec);
+void image_group_get_start(librados::ObjectReadOperation *op);
+int image_group_get_finish(ceph::buffer::list::const_iterator *iter,
+                           cls::rbd::GroupSpec *group_spec);
+int image_group_get(librados::IoCtx *ioctx, const std::string &oid,
+                    cls::rbd::GroupSpec *group_spec);
+int group_snap_set(librados::IoCtx *ioctx, const std::string &oid,
+                   const cls::rbd::GroupSnapshot &snapshot);
+int group_snap_remove(librados::IoCtx *ioctx, const std::string &oid,
+                      const std::string &snap_id);
+int group_snap_get_by_id(librados::IoCtx *ioctx, const std::string &oid,
+                         const std::string &snap_id,
+                         cls::rbd::GroupSnapshot *snapshot);
+int group_snap_list(librados::IoCtx *ioctx, const std::string &oid,
+                    const cls::rbd::GroupSnapshot &start,
+                    uint64_t max_return,
+                    std::vector<cls::rbd::GroupSnapshot> *snapshots);
+
+// operations on rbd_trash object
+void trash_add(librados::ObjectWriteOperation *op,
+               const std::string &id,
+               const cls::rbd::TrashImageSpec &trash_spec);
+int trash_add(librados::IoCtx *ioctx, const std::string &id,
+              const cls::rbd::TrashImageSpec &trash_spec);
+void trash_remove(librados::ObjectWriteOperation *op,
+                  const std::string &id);
+int trash_remove(librados::IoCtx *ioctx, const std::string &id);
+void trash_list_start(librados::ObjectReadOperation *op,
+                      const std::string &start, uint64_t max_return);
+int trash_list_finish(ceph::buffer::list::const_iterator *it,
+                      std::map<std::string, cls::rbd::TrashImageSpec> *entries);
+int trash_list(librados::IoCtx *ioctx,
+               const std::string &start, uint64_t max_return,
+               std::map<std::string, cls::rbd::TrashImageSpec> *entries);
+void trash_get_start(librados::ObjectReadOperation *op,
+                     const std::string &id);
+int trash_get_finish(ceph::buffer::list::const_iterator *it,
+                     cls::rbd::TrashImageSpec *trash_spec);
+int trash_get(librados::IoCtx *ioctx, const std::string &id,
+              cls::rbd::TrashImageSpec *trash_spec);
+void trash_state_set(librados::ObjectWriteOperation *op,
+                     const std::string &id,
+                     const cls::rbd::TrashImageState &trash_state,
+                     const cls::rbd::TrashImageState &expect_state);
+int trash_state_set(librados::IoCtx *ioctx, const std::string &id,
+                    const cls::rbd::TrashImageState &trash_state,
+                    const cls::rbd::TrashImageState &expect_state);
+
+// operations on rbd_namespace object
+void namespace_add(librados::ObjectWriteOperation *op,
+                   const std::string &name);
+int namespace_add(librados::IoCtx *ioctx, const std::string &name);
+void namespace_remove(librados::ObjectWriteOperation *op,
+                      const std::string &name);
+int namespace_remove(librados::IoCtx *ioctx, const std::string &name);
+void namespace_list_start(librados::ObjectReadOperation *op,
+                          const std::string &start, uint64_t max_return);
+int namespace_list_finish(ceph::buffer::list::const_iterator *it,
+                          std::list<std::string> *entries);
+int namespace_list(librados::IoCtx *ioctx,
+                   const std::string &start, uint64_t max_return,
+                   std::list<std::string> *entries);
+
+// operations on data objects
+void assert_snapc_seq(neorados::WriteOp* op,
+                      uint64_t snapc_seq,
+                      cls::rbd::AssertSnapcSeqState state);
+void assert_snapc_seq(librados::ObjectWriteOperation *op,
+                      uint64_t snapc_seq,
+                      cls::rbd::AssertSnapcSeqState state);
+int assert_snapc_seq(librados::IoCtx *ioctx, const std::string &oid,
+                     uint64_t snapc_seq,
+                     cls::rbd::AssertSnapcSeqState state);
+
+void copyup(neorados::WriteOp* op, ceph::buffer::list data);
+void copyup(librados::ObjectWriteOperation *op, ceph::buffer::list data);
+int copyup(librados::IoCtx *ioctx, const std::string &oid,
+           ceph::buffer::list data);
+
+void sparse_copyup(neorados::WriteOp* op,
+                   const std::vector<std::pair<uint64_t, uint64_t>>& extent_map,
+                   ceph::buffer::list data);
+void sparse_copyup(librados::ObjectWriteOperation *op,
+                   const std::map<uint64_t, uint64_t> &extent_map,
+                   ceph::buffer::list data);
+int sparse_copyup(librados::IoCtx *ioctx, const std::string &oid,
+                  const std::map<uint64_t, uint64_t> &extent_map,
+                  ceph::buffer::list data);
+
+void sparsify(librados::ObjectWriteOperation *op, size_t sparse_size,
+              bool remove_empty);
+int sparsify(librados::IoCtx *ioctx, const std::string &oid, size_t sparse_size,
+             bool remove_empty);
+
+} // namespace cls_client
+} // namespace librbd
+
+#endif // CEPH_LIBRBD_CLS_RBD_CLIENT_H
diff --git a/src/cls/rbd/cls_rbd_types.cc b/src/cls/rbd/cls_rbd_types.cc
new file mode 100644
index 000000000..e47f22777
--- /dev/null
+++ b/src/cls/rbd/cls_rbd_types.cc
@@ -0,0 +1,1359 @@
+// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
+// vim: ts=8 sw=2 smarttab
+
+#include <boost/variant.hpp>
+#include "cls/rbd/cls_rbd_types.h"
+#include "common/Formatter.h"
+
+namespace cls {
+namespace rbd {
+
+using std::istringstream;
+using std::ostringstream;
+using std::string;
+
+using ceph::bufferlist;
+using ceph::Formatter;
+
+std::ostream& operator<<(std::ostream& os,
+                         MirrorPeerDirection mirror_peer_direction) {
+  switch (mirror_peer_direction) {
+  case MIRROR_PEER_DIRECTION_RX:
+    os << "RX";
+    break;
+  case MIRROR_PEER_DIRECTION_TX:
+    os << "TX";
+    break;
+  case MIRROR_PEER_DIRECTION_RX_TX:
+    os << "RX/TX";
+    break;
+  default:
+    os << "unknown";
+    break;
+  }
+  return os;
+}
+
+void MirrorPeer::encode(bufferlist &bl) const {
+  ENCODE_START(2, 1, bl);
+  encode(uuid, bl);
+  encode(site_name, bl);
+  encode(client_name, bl);
+  int64_t pool_id = -1;
+  encode(pool_id, bl);
+
+  // v2
+  encode(static_cast<uint8_t>(mirror_peer_direction), bl);
+  encode(mirror_uuid, bl);
+  encode(last_seen, bl);
+  ENCODE_FINISH(bl);
+}
+
+void MirrorPeer::decode(bufferlist::const_iterator &it) {
+  DECODE_START(2, it);
+  decode(uuid, it);
+  decode(site_name, it);
+  decode(client_name, it);
+  int64_t pool_id;
+  decode(pool_id, it);
+
+  if (struct_v >= 2) {
+    uint8_t mpd;
+    decode(mpd, it);
+    mirror_peer_direction = static_cast<MirrorPeerDirection>(mpd);
+    decode(mirror_uuid, it);
+    decode(last_seen, it);
+  }
+
+  DECODE_FINISH(it);
+}
+
+void MirrorPeer::dump(Formatter *f) const {
+  f->dump_string("uuid", uuid);
+  f->dump_stream("direction") << mirror_peer_direction;
+  f->dump_string("site_name", site_name);
+  f->dump_string("mirror_uuid", mirror_uuid);
+  f->dump_string("client_name", client_name);
+  f->dump_stream("last_seen") << last_seen;
+}
+
+void MirrorPeer::generate_test_instances(std::list<MirrorPeer*> &o) {
+  o.push_back(new MirrorPeer());
+  o.push_back(new MirrorPeer("uuid-123", MIRROR_PEER_DIRECTION_RX, "site A",
+                             "client name", ""));
+  o.push_back(new MirrorPeer("uuid-234", MIRROR_PEER_DIRECTION_TX, "site B",
+                             "", "mirror_uuid"));
+  o.push_back(new MirrorPeer("uuid-345", MIRROR_PEER_DIRECTION_RX_TX, "site C",
+                             "client name", "mirror_uuid"));
+}
+
+bool MirrorPeer::operator==(const MirrorPeer &rhs) const {
+  return (uuid == rhs.uuid &&
+          mirror_peer_direction == rhs.mirror_peer_direction &&
+          site_name == rhs.site_name &&
+          client_name == rhs.client_name &&
+          mirror_uuid == rhs.mirror_uuid &&
+          last_seen == rhs.last_seen);
+}
+
+std::ostream& operator<<(std::ostream& os, const MirrorMode& mirror_mode) {
+  switch (mirror_mode) {
+  case MIRROR_MODE_DISABLED:
+    os << "disabled";
+    break;
+  case MIRROR_MODE_IMAGE:
+    os << "image";
+    break;
+  case MIRROR_MODE_POOL:
+    os << "pool";
+    break;
+  default:
+    os << "unknown (" << static_cast<uint32_t>(mirror_mode) << ")";
+    break;
+  }
+  return os;
+}
+
+std::ostream& operator<<(std::ostream& os, const MirrorPeer& peer) {
+  os << "["
+     << "uuid=" << peer.uuid << ", "
+     << "direction=" << peer.mirror_peer_direction << ", "
+     << "site_name=" << peer.site_name << ", "
+     << "client_name=" << peer.client_name << ", "
+     << "mirror_uuid=" << peer.mirror_uuid << ", "
+     << "last_seen=" << peer.last_seen
+     << "]";
+  return os;
+}
+
+void MirrorImage::encode(bufferlist &bl) const {
+  ENCODE_START(2, 1, bl);
+  encode(global_image_id, bl);
+  encode(static_cast<uint8_t>(state), bl);
+  encode(static_cast<uint8_t>(mode), bl);
+  ENCODE_FINISH(bl);
+}
+
+void MirrorImage::decode(bufferlist::const_iterator &it) {
+  uint8_t int_state;
+  DECODE_START(2, it);
+  decode(global_image_id, it);
+  decode(int_state, it);
+  state = static_cast<MirrorImageState>(int_state);
+  if (struct_v >= 2) {
+    uint8_t int_mode;
+    decode(int_mode, it);
+    mode = static_cast<MirrorImageMode>(int_mode);
+  }
+  DECODE_FINISH(it);
+}
+
+void MirrorImage::dump(Formatter *f) const {
+  f->dump_stream("mode") << mode;
+  f->dump_string("global_image_id", global_image_id);
+  f->dump_stream("state") << state;
+}
+
+void MirrorImage::generate_test_instances(std::list<MirrorImage*> &o) {
+  o.push_back(new MirrorImage());
+  o.push_back(new MirrorImage(MIRROR_IMAGE_MODE_JOURNAL, "uuid-123",
+                              MIRROR_IMAGE_STATE_ENABLED));
+  o.push_back(new MirrorImage(MIRROR_IMAGE_MODE_SNAPSHOT, "uuid-abc",
+                              MIRROR_IMAGE_STATE_DISABLING));
+}
+
+bool MirrorImage::operator==(const MirrorImage &rhs) const {
+  return mode == rhs.mode && global_image_id == rhs.global_image_id &&
+         state == rhs.state;
+}
+
+bool MirrorImage::operator<(const MirrorImage &rhs) const {
+  if (mode != rhs.mode) {
+    return mode < rhs.mode;
+  }
+  if (global_image_id != rhs.global_image_id) {
+    return global_image_id < rhs.global_image_id;
+  }
+  return state < rhs.state;
+}
+
+std::ostream& operator<<(std::ostream& os, const MirrorImageMode& mirror_mode) {
+  switch (mirror_mode) {
+  case MIRROR_IMAGE_MODE_JOURNAL:
+    os << "journal";
+    break;
+  case MIRROR_IMAGE_MODE_SNAPSHOT:
+    os << "snapshot";
+    break;
+  default:
+    os << "unknown (" << static_cast<uint32_t>(mirror_mode) << ")";
+    break;
+  }
+  return os;
+}
+
+std::ostream& operator<<(std::ostream& os, const MirrorImageState& mirror_state) {
+  switch (mirror_state) {
+  case MIRROR_IMAGE_STATE_DISABLING:
+    os << "disabling";
+    break;
+  case MIRROR_IMAGE_STATE_ENABLED:
+    os << "enabled";
+    break;
+  case MIRROR_IMAGE_STATE_DISABLED:
+    os << "disabled";
+    break;
+  default:
+    os << "unknown (" << static_cast<uint32_t>(mirror_state) << ")";
+    break;
+  }
+  return os;
+}
+
+std::ostream& operator<<(std::ostream& os, const MirrorImage& mirror_image) {
+  os << "["
+     << "mode=" << mirror_image.mode << ", "
+     << "global_image_id=" << mirror_image.global_image_id << ", "
+     << "state=" << mirror_image.state << "]";
+  return os;
+}
+
+std::ostream& operator<<(std::ostream& os,
+                         const MirrorImageStatusState& state) {
+  switch (state) {
+  case MIRROR_IMAGE_STATUS_STATE_UNKNOWN:
+    os << "unknown";
+    break;
+  case MIRROR_IMAGE_STATUS_STATE_ERROR:
+    os << "error";
+    break;
+  case MIRROR_IMAGE_STATUS_STATE_SYNCING:
+    os << "syncing";
+    break;
+  case MIRROR_IMAGE_STATUS_STATE_STARTING_REPLAY:
+    os << "starting_replay";
+    break;
+  case MIRROR_IMAGE_STATUS_STATE_REPLAYING:
+    os << "replaying";
+    break;
+  case MIRROR_IMAGE_STATUS_STATE_STOPPING_REPLAY:
+    os << "stopping_replay";
+    break;
+  case MIRROR_IMAGE_STATUS_STATE_STOPPED:
+    os << "stopped";
+    break;
+  default:
+    os << "unknown (" << static_cast<uint32_t>(state) << ")";
+    break;
+  }
+  return os;
+}
+
+const std::string MirrorImageSiteStatus::LOCAL_MIRROR_UUID(""); // empty mirror uuid
+
+void MirrorImageSiteStatus::encode_meta(uint8_t version, bufferlist &bl) const {
+  if (version >= 2) {
+    ceph::encode(mirror_uuid, bl);
+  }
+  cls::rbd::encode(state, bl);
+  ceph::encode(description, bl);
+  ceph::encode(last_update, bl);
+  ceph::encode(up, bl);
+}
+
+void MirrorImageSiteStatus::decode_meta(uint8_t version,
+                                        bufferlist::const_iterator &it) {
+  if (version < 2) {
+    mirror_uuid = LOCAL_MIRROR_UUID;
+  } else {
+    ceph::decode(mirror_uuid, it);
+  }
+
+  cls::rbd::decode(state, it);
+  ceph::decode(description, it);
+  ::decode(last_update, it);
+  ceph::decode(up, it);
+}
+
+void MirrorImageSiteStatus::encode(bufferlist &bl) const {
+  // break compatibility when site-name is provided
+  uint8_t version = (mirror_uuid == LOCAL_MIRROR_UUID ? 1 : 2);
+  ENCODE_START(version, version, bl);
+  encode_meta(version, bl);
+  ENCODE_FINISH(bl);
+}
+
+void MirrorImageSiteStatus::decode(bufferlist::const_iterator &it) {
+  DECODE_START(2, it);
+  decode_meta(struct_v, it);
+  DECODE_FINISH(it);
+}
+
+void MirrorImageSiteStatus::dump(Formatter *f) const {
+  f->dump_string("state", state_to_string());
+  f->dump_string("description", description);
+  f->dump_stream("last_update") << last_update;
+}
+
+std::string MirrorImageSiteStatus::state_to_string() const {
+  std::stringstream ss;
+  ss << (up ? "up+" : "down+") << state;
+  return ss.str();
+}
+
+void MirrorImageSiteStatus::generate_test_instances(
+  std::list<MirrorImageSiteStatus*> &o) {
+  o.push_back(new MirrorImageSiteStatus());
+  o.push_back(new MirrorImageSiteStatus("", MIRROR_IMAGE_STATUS_STATE_REPLAYING,
+                                        ""));
+  o.push_back(new MirrorImageSiteStatus("", MIRROR_IMAGE_STATUS_STATE_ERROR,
+                                        "error"));
+  o.push_back(new MirrorImageSiteStatus("2fb68ca9-1ba0-43b3-8cdf-8c5a9db71e65",
+                                        MIRROR_IMAGE_STATUS_STATE_STOPPED, ""));
+}
+
+bool MirrorImageSiteStatus::operator==(const MirrorImageSiteStatus &rhs) const {
+  return state == rhs.state && description == rhs.description && up == rhs.up;
+}
+
+std::ostream& operator<<(std::ostream& os,
+                         const MirrorImageSiteStatus& status) {
+  os << "{"
+     << "state=" << status.state_to_string() << ", "
+     << "description=" << status.description << ", "
+     << "last_update=" << status.last_update << "]}";
+  return os;
+}
+
+void MirrorImageSiteStatusOnDisk::encode_meta(bufferlist &bl,
+                                              uint64_t features) const {
+  ENCODE_START(1, 1, bl);
+  auto sanitized_origin = origin;
+  sanitize_entity_inst(&sanitized_origin);
+  encode(sanitized_origin, bl, features);
+  ENCODE_FINISH(bl);
+}
+
+void MirrorImageSiteStatusOnDisk::encode(bufferlist &bl,
+                                         uint64_t features) const {
+  encode_meta(bl, features);
+  cls::rbd::MirrorImageSiteStatus::encode(bl);
+}
+
+void MirrorImageSiteStatusOnDisk::decode_meta(bufferlist::const_iterator &it) {
+  DECODE_START(1, it);
+  decode(origin, it);
+  sanitize_entity_inst(&origin);
+  DECODE_FINISH(it);
+}
+
+void MirrorImageSiteStatusOnDisk::decode(bufferlist::const_iterator &it) {
+  decode_meta(it);
+  cls::rbd::MirrorImageSiteStatus::decode(it);
+}
+
+void MirrorImageSiteStatusOnDisk::generate_test_instances(
+    std::list<MirrorImageSiteStatusOnDisk*> &o) {
+  o.push_back(new MirrorImageSiteStatusOnDisk());
+  o.push_back(new MirrorImageSiteStatusOnDisk(
+    {"", MIRROR_IMAGE_STATUS_STATE_ERROR, "error"}));
+  o.push_back(new MirrorImageSiteStatusOnDisk(
+    {"siteA", MIRROR_IMAGE_STATUS_STATE_STOPPED, ""}));
+}
+
+int MirrorImageStatus::get_local_mirror_image_site_status(
+    MirrorImageSiteStatus* status) const {
+  auto it = std::find_if(
+    mirror_image_site_statuses.begin(),
+    mirror_image_site_statuses.end(),
+    [](const MirrorImageSiteStatus& status) {
+      return status.mirror_uuid == MirrorImageSiteStatus::LOCAL_MIRROR_UUID;
+    });
+  if (it == mirror_image_site_statuses.end()) {
+    return -ENOENT;
+  }
+
+  *status = *it;
+  return 0;
+}
+
+void MirrorImageStatus::encode(bufferlist &bl) const {
+  // don't break compatibility for extra site statuses
+  ENCODE_START(2, 1, bl);
+
+  // local site status
+  MirrorImageSiteStatus local_status;
+  int r = get_local_mirror_image_site_status(&local_status);
+  local_status.encode_meta(1, bl);
+
+  bool local_status_valid = (r >= 0);
+  encode(local_status_valid, bl);
+
+  // remote site statuses
+  __u32 n = mirror_image_site_statuses.size();
+  if (local_status_valid) {
+    --n;
+  }
+  encode(n, bl);
+
+  for (auto& status : mirror_image_site_statuses) {
+    if (status.mirror_uuid == MirrorImageSiteStatus::LOCAL_MIRROR_UUID) {
+      continue;
+    }
+    status.encode_meta(2, bl);
+  }
+  ENCODE_FINISH(bl);
+}
+
+void MirrorImageStatus::decode(bufferlist::const_iterator &it) {
+  DECODE_START(2, it);
+
+  // local site status
+  MirrorImageSiteStatus local_status;
+  local_status.decode_meta(1, it);
+
+  if (struct_v < 2) {
+    mirror_image_site_statuses.push_back(local_status);
+  } else {
+    bool local_status_valid;
+    decode(local_status_valid, it);
+
+    __u32 n;
+    decode(n, it);
+    if (local_status_valid) {
+      ++n;
+    }
+
+    mirror_image_site_statuses.resize(n);
+    for (auto status_it = mirror_image_site_statuses.begin();
+         status_it != mirror_image_site_statuses.end(); ++status_it) {
+      if (local_status_valid &&
+          status_it == mirror_image_site_statuses.begin()) {
+        *status_it = local_status;
+        continue;
+      }
+
+      // remote site status
+      status_it->decode_meta(struct_v, it);
+    }
+  }
+  DECODE_FINISH(it);
+}
+
+void MirrorImageStatus::dump(Formatter *f) const {
+  MirrorImageSiteStatus local_status;
+  int r = get_local_mirror_image_site_status(&local_status);
+  if (r >= 0) {
+    local_status.dump(f);
+  }
+
+  f->open_array_section("remotes");
+  for (auto& status : mirror_image_site_statuses) {
+    if (status.mirror_uuid == MirrorImageSiteStatus::LOCAL_MIRROR_UUID) {
+      continue;
+    }
+
+    f->open_object_section("remote");
+    status.dump(f);
+    f->close_section();
+  }
+  f->close_section();
+}
+
+bool MirrorImageStatus::operator==(const MirrorImageStatus &rhs) const {
+  return (mirror_image_site_statuses == rhs.mirror_image_site_statuses);
+}
+
+void MirrorImageStatus::generate_test_instances(
+    std::list<MirrorImageStatus*> &o) {
+  o.push_back(new MirrorImageStatus());
+  o.push_back(new MirrorImageStatus({{"", MIRROR_IMAGE_STATUS_STATE_ERROR, ""}}));
+  o.push_back(new MirrorImageStatus({{"", MIRROR_IMAGE_STATUS_STATE_STOPPED, ""},
+                                     {"siteA", MIRROR_IMAGE_STATUS_STATE_REPLAYING, ""}}));
+}
+
+std::ostream& operator<<(std::ostream& os,
+                         const MirrorImageStatus& status) {
+  os << "{";
+  MirrorImageSiteStatus local_status;
+  int r = status.get_local_mirror_image_site_status(&local_status);
+  if (r >= 0) {
+    os << "state=" << local_status.state_to_string() << ", "
+       << "description=" << local_status.description << ", "
+       << "last_update=" << local_status.last_update << ", ";
+  }
+
+  os << "remotes=[";
+  for (auto& remote_status : status.mirror_image_site_statuses) {
+    if (remote_status.mirror_uuid == MirrorImageSiteStatus::LOCAL_MIRROR_UUID) {
+      continue;
+    }
+
+    os << "{"
+       << "mirror_uuid=" << remote_status.mirror_uuid<< ", "
+       << "state=" << remote_status.state_to_string() << ", "
+       << "description=" << remote_status.description << ", "
+       << "last_update=" << remote_status.last_update
+       << "}";
+  }
+  os << "]}";
+  return os;
+}
+
+void ParentImageSpec::encode(bufferlist& bl) const {
+  ENCODE_START(1, 1, bl);
+  encode(pool_id, bl);
+  encode(pool_namespace, bl);
+  encode(image_id, bl);
+  encode(snap_id, bl);
+  ENCODE_FINISH(bl);
+}
+
+void ParentImageSpec::decode(bufferlist::const_iterator& bl) {
+  DECODE_START(1, bl);
+  decode(pool_id, bl);
+  decode(pool_namespace, bl);
+  decode(image_id, bl);
+  decode(snap_id, bl);
+  DECODE_FINISH(bl);
+}
+
+void ParentImageSpec::dump(Formatter *f) const {
+  f->dump_int("pool_id", pool_id);
+  f->dump_string("pool_namespace", pool_namespace);
+  f->dump_string("image_id", image_id);
+  f->dump_unsigned("snap_id", snap_id);
+}
+
+void ParentImageSpec::generate_test_instances(std::list<ParentImageSpec*>& o) {
+  o.push_back(new ParentImageSpec{});
+  o.push_back(new ParentImageSpec{1, "", "foo", 3});
+  o.push_back(new ParentImageSpec{1, "ns", "foo", 3});
+}
+
+std::ostream& operator<<(std::ostream& os, const ParentImageSpec& rhs) {
+  os << "["
+     << "pool_id=" << rhs.pool_id << ", "
+     << "pool_namespace=" << rhs.pool_namespace << ", "
+     << "image_id=" << rhs.image_id << ", "
+     << "snap_id=" << rhs.snap_id
+     << "]";
+  return os;
+}
+
+void ChildImageSpec::encode(bufferlist &bl) const {
+  ENCODE_START(2, 1, bl);
+  encode(pool_id, bl);
+  encode(image_id, bl);
+  encode(pool_namespace, bl);
+  ENCODE_FINISH(bl);
+}
+
+void ChildImageSpec::decode(bufferlist::const_iterator &it) {
+  DECODE_START(2, it);
+  decode(pool_id, it);
+  decode(image_id, it);
+  if (struct_v >= 2) {
+    decode(pool_namespace, it);
+  }
+  DECODE_FINISH(it);
+}
+
+void ChildImageSpec::dump(Formatter *f) const {
+  f->dump_int("pool_id", pool_id);
+  f->dump_string("pool_namespace", pool_namespace);
+  f->dump_string("image_id", image_id);
+}
+
+void ChildImageSpec::generate_test_instances(std::list<ChildImageSpec*> &o) {
+  o.push_back(new ChildImageSpec());
+  o.push_back(new ChildImageSpec(123, "", "abc"));
+  o.push_back(new ChildImageSpec(123, "ns", "abc"));
+}
+
+std::ostream& operator<<(std::ostream& os, const ChildImageSpec& rhs) {
+  os << "["
+     << "pool_id=" << rhs.pool_id << ", "
+     << "pool_namespace=" << rhs.pool_namespace << ", "
+     << "image_id=" << rhs.image_id
+     << "]";
+  return os;
+}
+
+void GroupImageSpec::encode(bufferlist &bl) const {
+  ENCODE_START(1, 1, bl);
+  encode(image_id, bl);
+  encode(pool_id, bl);
+  ENCODE_FINISH(bl);
+}
+
+void GroupImageSpec::decode(bufferlist::const_iterator &it) {
+  DECODE_START(1, it);
+  decode(image_id, it);
+  decode(pool_id, it);
+  DECODE_FINISH(it);
+}
+
+void GroupImageSpec::dump(Formatter *f) const {
+  f->dump_string("image_id", image_id);
+  f->dump_int("pool_id", pool_id);
+}
+
+int GroupImageSpec::from_key(const std::string &image_key,
+				    GroupImageSpec *spec) {
+  if (nullptr == spec) return -EINVAL;
+  int prefix_len = cls::rbd::RBD_GROUP_IMAGE_KEY_PREFIX.size();
+  std::string data_string = image_key.substr(prefix_len,
+					     image_key.size() - prefix_len);
+  size_t p = data_string.find("_");
+  if (std::string::npos == p) {
+    return -EIO;
+  }
+  data_string[p] = ' ';
+
+  istringstream iss(data_string);
+  uint64_t pool_id;
+  string image_id;
+  iss >> std::hex >> pool_id >> image_id;
+
+  spec->image_id = image_id;
+  spec->pool_id = pool_id;
+  return 0;
+}
+
+std::string GroupImageSpec::image_key() {
+  if (-1 == pool_id)
+    return "";
+  else {
+    ostringstream oss;
+    oss << RBD_GROUP_IMAGE_KEY_PREFIX << std::setw(16)
+	<< std::setfill('0') << std::hex << pool_id << "_" << image_id;
+    return oss.str();
+  }
+}
+
+void GroupImageSpec::generate_test_instances(std::list<GroupImageSpec*> &o) {
+  o.push_back(new GroupImageSpec("10152ae8944a", 0));
+  o.push_back(new GroupImageSpec("1018643c9869", 3));
+}
+
+void GroupImageStatus::encode(bufferlist &bl) const {
+  ENCODE_START(1, 1, bl);
+  encode(spec, bl);
+  encode(state, bl);
+  ENCODE_FINISH(bl);
+}
+
+void GroupImageStatus::decode(bufferlist::const_iterator &it) {
+  DECODE_START(1, it);
+  decode(spec, it);
+  decode(state, it);
+  DECODE_FINISH(it);
+}
+
+std::string GroupImageStatus::state_to_string() const {
+  std::stringstream ss;
+  if (state == GROUP_IMAGE_LINK_STATE_INCOMPLETE) {
+    ss << "incomplete";
+  }
+  if (state == GROUP_IMAGE_LINK_STATE_ATTACHED) {
+    ss << "attached";
+  }
+  return ss.str();
+}
+
+void GroupImageStatus::dump(Formatter *f) const {
+  spec.dump(f);
+  f->dump_string("state", state_to_string());
+}
+
+void GroupImageStatus::generate_test_instances(std::list<GroupImageStatus*> &o) {
+  o.push_back(new GroupImageStatus(GroupImageSpec("10152ae8944a", 0), GROUP_IMAGE_LINK_STATE_ATTACHED));
+  o.push_back(new GroupImageStatus(GroupImageSpec("1018643c9869", 3), GROUP_IMAGE_LINK_STATE_ATTACHED));
+  o.push_back(new GroupImageStatus(GroupImageSpec("10152ae8944a", 0), GROUP_IMAGE_LINK_STATE_INCOMPLETE));
+  o.push_back(new GroupImageStatus(GroupImageSpec("1018643c9869", 3), GROUP_IMAGE_LINK_STATE_INCOMPLETE));
+}
+
+
+void GroupSpec::encode(bufferlist &bl) const {
+  ENCODE_START(1, 1, bl);
+  encode(pool_id, bl);
+  encode(group_id, bl);
+  ENCODE_FINISH(bl);
+}
+
+void GroupSpec::decode(bufferlist::const_iterator &it) {
+  DECODE_START(1, it);
+  decode(pool_id, it);
+  decode(group_id, it);
+  DECODE_FINISH(it);
+}
+
+void GroupSpec::dump(Formatter *f) const {
+  f->dump_string("group_id", group_id);
+  f->dump_int("pool_id", pool_id);
+}
+
+bool GroupSpec::is_valid() const {
+  return (!group_id.empty()) && (pool_id != -1);
+}
+
+void GroupSpec::generate_test_instances(std::list<GroupSpec *> &o) {
+  o.push_back(new GroupSpec("10152ae8944a", 0));
+  o.push_back(new GroupSpec("1018643c9869", 3));
+}
+
+void GroupSnapshotNamespace::encode(bufferlist& bl) const {
+  using ceph::encode;
+  encode(group_pool, bl);
+  encode(group_id, bl);
+  encode(group_snapshot_id, bl);
+}
+
+void GroupSnapshotNamespace::decode(bufferlist::const_iterator& it) {
+  using ceph::decode;
+  decode(group_pool, it);
+  decode(group_id, it);
+  decode(group_snapshot_id, it);
+}
+
+void GroupSnapshotNamespace::dump(Formatter *f) const {
+  f->dump_int("group_pool", group_pool);
+  f->dump_string("group_id", group_id);
+  f->dump_string("group_snapshot_id", group_snapshot_id);
+}
+
+void TrashSnapshotNamespace::encode(bufferlist& bl) const {
+  using ceph::encode;
+  encode(original_name, bl);
+  encode(static_cast<uint32_t>(original_snapshot_namespace_type), bl);
+}
+
+void TrashSnapshotNamespace::decode(bufferlist::const_iterator& it) {
+  using ceph::decode;
+  decode(original_name, it);
+  uint32_t snap_type;
+  decode(snap_type, it);
+  original_snapshot_namespace_type = static_cast<SnapshotNamespaceType>(
+    snap_type);
+}
+
+void TrashSnapshotNamespace::dump(Formatter *f) const {
+  f->dump_string("original_name", original_name);
+  f->dump_stream("original_snapshot_namespace")
+    << original_snapshot_namespace_type;
+}
+
+void MirrorSnapshotNamespace::encode(bufferlist& bl) const {
+  using ceph::encode;
+  encode(state, bl);
+  encode(complete, bl);
+  encode(mirror_peer_uuids, bl);
+  encode(primary_mirror_uuid, bl);
+  encode(primary_snap_id, bl);
+  encode(last_copied_object_number, bl);
+  encode(snap_seqs, bl);
+}
+
+void MirrorSnapshotNamespace::decode(bufferlist::const_iterator& it) {
+  using ceph::decode;
+  decode(state, it);
+  decode(complete, it);
+  decode(mirror_peer_uuids, it);
+  decode(primary_mirror_uuid, it);
+  decode(primary_snap_id, it);
+  decode(last_copied_object_number, it);
+  decode(snap_seqs, it);
+}
+
+void MirrorSnapshotNamespace::dump(Formatter *f) const {
+  f->dump_stream("state") << state;
+  f->dump_bool("complete", complete);
+  f->open_array_section("mirror_peer_uuids");
+  for (auto &peer : mirror_peer_uuids) {
+    f->dump_string("mirror_peer_uuid", peer);
+  }
+  f->close_section();
+  if (is_primary()) {
+    f->dump_unsigned("clean_since_snap_id", clean_since_snap_id);
+  } else {
+    f->dump_string("primary_mirror_uuid", primary_mirror_uuid);
+    f->dump_unsigned("primary_snap_id", primary_snap_id);
+    f->dump_unsigned("last_copied_object_number", last_copied_object_number);
+    f->dump_stream("snap_seqs") << snap_seqs;
+  }
+}
+
+class EncodeSnapshotNamespaceVisitor : public boost::static_visitor<void> {
+public:
+  explicit EncodeSnapshotNamespaceVisitor(bufferlist &bl) : m_bl(bl) {
+  }
+
+  template <typename T>
+  inline void operator()(const T& t) const {
+    using ceph::encode;
+    encode(static_cast<uint32_t>(T::SNAPSHOT_NAMESPACE_TYPE), m_bl);
+    t.encode(m_bl);
+  }
+
+private:
+  bufferlist &m_bl;
+};
+
+class DecodeSnapshotNamespaceVisitor : public boost::static_visitor<void> {
+public:
+  DecodeSnapshotNamespaceVisitor(bufferlist::const_iterator &iter)
+    : m_iter(iter) {
+  }
+
+  template <typename T>
+  inline void operator()(T& t) const {
+    t.decode(m_iter);
+  }
+private:
+  bufferlist::const_iterator &m_iter;
+};
+
+class DumpSnapshotNamespaceVisitor : public boost::static_visitor<void> {
+public:
+  explicit DumpSnapshotNamespaceVisitor(Formatter *formatter, const std::string &key)
+    : m_formatter(formatter), m_key(key) {}
+
+  template <typename T>
+  inline void operator()(const T& t) const {
+    auto type = T::SNAPSHOT_NAMESPACE_TYPE;
+    m_formatter->dump_string(m_key.c_str(), stringify(type));
+    t.dump(m_formatter);
+  }
+private:
+  ceph::Formatter *m_formatter;
+  std::string m_key;
+};
+
+class GetTypeVisitor : public boost::static_visitor<SnapshotNamespaceType> {
+public:
+  template <typename T>
+  inline SnapshotNamespaceType operator()(const T&) const {
+    return static_cast<SnapshotNamespaceType>(T::SNAPSHOT_NAMESPACE_TYPE);
+  }
+};
+
+SnapshotNamespaceType get_snap_namespace_type(
+    const SnapshotNamespace& snapshot_namespace) {
+  return static_cast<SnapshotNamespaceType>(boost::apply_visitor(
+    GetTypeVisitor(), snapshot_namespace));
+}
+
+void SnapshotInfo::encode(bufferlist& bl) const {
+  ENCODE_START(1, 1, bl);
+  encode(id, bl);
+  encode(snapshot_namespace, bl);
+  encode(name, bl);
+  encode(image_size, bl);
+  encode(timestamp, bl);
+  encode(child_count, bl);
+  ENCODE_FINISH(bl);
+}
+
+void SnapshotInfo::decode(bufferlist::const_iterator& it) {
+  DECODE_START(1, it);
+  decode(id, it);
+  decode(snapshot_namespace, it);
+  decode(name, it);
+  decode(image_size, it);
+  decode(timestamp, it);
+  decode(child_count, it);
+  DECODE_FINISH(it);
+}
+
+void SnapshotInfo::dump(Formatter *f) const {
+  f->dump_unsigned("id", id);
+  f->open_object_section("namespace");
+  boost::apply_visitor(DumpSnapshotNamespaceVisitor(f, "type"),
+                       snapshot_namespace);
+  f->close_section();
+  f->dump_string("name", name);
+  f->dump_unsigned("image_size", image_size);
+  f->dump_stream("timestamp") << timestamp;
+}
+
+void SnapshotInfo::generate_test_instances(std::list<SnapshotInfo*> &o) {
+  o.push_back(new SnapshotInfo(1ULL, UserSnapshotNamespace{}, "snap1", 123,
+                               {123456, 0}, 12));
+  o.push_back(new SnapshotInfo(2ULL,
+                               GroupSnapshotNamespace{567, "group1", "snap1"},
+                               "snap1", 123, {123456, 0}, 987));
+  o.push_back(new SnapshotInfo(3ULL,
+                               TrashSnapshotNamespace{
+                                 SNAPSHOT_NAMESPACE_TYPE_USER, "snap1"},
+                               "12345", 123, {123456, 0}, 429));
+  o.push_back(new SnapshotInfo(1ULL,
+                               MirrorSnapshotNamespace{MIRROR_SNAPSHOT_STATE_PRIMARY,
+                                                       {"1", "2"}, "", CEPH_NOSNAP},
+                               "snap1", 123, {123456, 0}, 12));
+  o.push_back(new SnapshotInfo(1ULL,
+                               MirrorSnapshotNamespace{MIRROR_SNAPSHOT_STATE_NON_PRIMARY,
+                                                       {"1", "2"}, "uuid", 123},
+                               "snap1", 123, {123456, 0}, 12));
+}
+
+void SnapshotNamespace::encode(bufferlist& bl) const {
+  ENCODE_START(1, 1, bl);
+  boost::apply_visitor(EncodeSnapshotNamespaceVisitor(bl), *this);
+  ENCODE_FINISH(bl);
+}
+
+void SnapshotNamespace::decode(bufferlist::const_iterator &p)
+{
+  DECODE_START(1, p);
+  uint32_t snap_type;
+  decode(snap_type, p);
+  switch (snap_type) {
+    case cls::rbd::SNAPSHOT_NAMESPACE_TYPE_USER:
+      *this = UserSnapshotNamespace();
+      break;
+    case cls::rbd::SNAPSHOT_NAMESPACE_TYPE_GROUP:
+      *this = GroupSnapshotNamespace();
+      break;
+    case cls::rbd::SNAPSHOT_NAMESPACE_TYPE_TRASH:
+      *this = TrashSnapshotNamespace();
+      break;
+    case cls::rbd::SNAPSHOT_NAMESPACE_TYPE_MIRROR:
+      *this = MirrorSnapshotNamespace();
+      break;
+    default:
+      *this = UnknownSnapshotNamespace();
+      break;
+  }
+  boost::apply_visitor(DecodeSnapshotNamespaceVisitor(p), *this);
+  DECODE_FINISH(p);
+}
+
+void SnapshotNamespace::dump(Formatter *f) const {
+  boost::apply_visitor(
+    DumpSnapshotNamespaceVisitor(f, "snapshot_namespace_type"), *this);
+}
+
+void SnapshotNamespace::generate_test_instances(std::list<SnapshotNamespace*> &o) {
+  o.push_back(new SnapshotNamespace(UserSnapshotNamespace()));
+  o.push_back(new SnapshotNamespace(GroupSnapshotNamespace(0, "10152ae8944a",
+                                                           "2118643c9732")));
+  o.push_back(new SnapshotNamespace(GroupSnapshotNamespace(5, "1018643c9869",
+                                                           "33352be8933c")));
+  o.push_back(new SnapshotNamespace(TrashSnapshotNamespace()));
+  o.push_back(new SnapshotNamespace(MirrorSnapshotNamespace(MIRROR_SNAPSHOT_STATE_PRIMARY,
+                                                            {"peer uuid"},
+                                                            "", CEPH_NOSNAP)));
+  o.push_back(new SnapshotNamespace(MirrorSnapshotNamespace(MIRROR_SNAPSHOT_STATE_PRIMARY_DEMOTED,
+                                                            {"peer uuid"},
+                                                            "", CEPH_NOSNAP)));
+  o.push_back(new SnapshotNamespace(MirrorSnapshotNamespace(MIRROR_SNAPSHOT_STATE_NON_PRIMARY,
+                                                            {"peer uuid"},
+                                                            "uuid", 123)));
+  o.push_back(new SnapshotNamespace(MirrorSnapshotNamespace(MIRROR_SNAPSHOT_STATE_NON_PRIMARY_DEMOTED,
+                                                            {"peer uuid"},
+                                                            "uuid", 123)));
+}
+
+std::ostream& operator<<(std::ostream& os, const SnapshotNamespaceType& type) {
+  switch (type) {
+  case SNAPSHOT_NAMESPACE_TYPE_USER:
+    os << "user";
+    break;
+  case SNAPSHOT_NAMESPACE_TYPE_GROUP:
+    os << "group";
+    break;
+  case SNAPSHOT_NAMESPACE_TYPE_TRASH:
+    os << "trash";
+    break;
+  case SNAPSHOT_NAMESPACE_TYPE_MIRROR:
+    os << "mirror";
+    break;
+  default:
+    os << "unknown";
+    break;
+  }
+  return os;
+}
+
+std::ostream& operator<<(std::ostream& os, const UserSnapshotNamespace& ns) {
+  os << "[" << SNAPSHOT_NAMESPACE_TYPE_USER << "]";
+  return os;
+}
+
+std::ostream& operator<<(std::ostream& os, const GroupSnapshotNamespace& ns) {
+  os << "[" << SNAPSHOT_NAMESPACE_TYPE_GROUP << " "
+     << "group_pool=" << ns.group_pool << ", "
+     << "group_id=" << ns.group_id << ", "
+     << "group_snapshot_id=" << ns.group_snapshot_id << "]";
+  return os;
+}
+
+std::ostream& operator<<(std::ostream& os, const TrashSnapshotNamespace& ns) {
+  os << "[" << SNAPSHOT_NAMESPACE_TYPE_TRASH << " "
+     << "original_name=" << ns.original_name << ", "
+     << "original_snapshot_namespace=" << ns.original_snapshot_namespace_type
+     << "]";
+  return os;
+}
+
+std::ostream& operator<<(std::ostream& os, const MirrorSnapshotNamespace& ns) {
+  os << "[" << SNAPSHOT_NAMESPACE_TYPE_MIRROR << " "
+     << "state=" << ns.state << ", "
+     << "complete=" << ns.complete << ", "
+     << "mirror_peer_uuids=" << ns.mirror_peer_uuids << ", ";
+  if (ns.is_primary()) {
+     os << "clean_since_snap_id=" << ns.clean_since_snap_id;
+  } else {
+     os << "primary_mirror_uuid=" << ns.primary_mirror_uuid << ", "
+        << "primary_snap_id=" << ns.primary_snap_id << ", "
+        << "last_copied_object_number=" << ns.last_copied_object_number << ", "
+        << "snap_seqs=" << ns.snap_seqs;
+  }
+  os << "]";
+  return os;
+}
+
+std::ostream& operator<<(std::ostream& os, const UnknownSnapshotNamespace& ns) {
+  os << "[unknown]";
+  return os;
+}
+
+std::ostream& operator<<(std::ostream& os, MirrorSnapshotState type) {
+  switch (type) {
+  case MIRROR_SNAPSHOT_STATE_PRIMARY:
+    os << "primary";
+    break;
+  case MIRROR_SNAPSHOT_STATE_PRIMARY_DEMOTED:
+    os << "primary (demoted)";
+    break;
+  case MIRROR_SNAPSHOT_STATE_NON_PRIMARY:
+    os << "non-primary";
+    break;
+  case MIRROR_SNAPSHOT_STATE_NON_PRIMARY_DEMOTED:
+    os << "non-primary (demoted)";
+    break;
+  default:
+    os << "unknown";
+    break;
+  }
+  return os;
+}
+
+void ImageSnapshotSpec::encode(bufferlist& bl) const {
+  using ceph::encode;
+  ENCODE_START(1, 1, bl);
+  encode(pool, bl);
+  encode(image_id, bl);
+  encode(snap_id, bl);
+  ENCODE_FINISH(bl);
+}
+
+void ImageSnapshotSpec::decode(bufferlist::const_iterator& it) {
+  using ceph::decode;
+  DECODE_START(1, it);
+  decode(pool, it);
+  decode(image_id, it);
+  decode(snap_id, it);
+  DECODE_FINISH(it);
+}
+
+void ImageSnapshotSpec::dump(Formatter *f) const {
+  f->dump_int("pool", pool);
+  f->dump_string("image_id", image_id);
+  f->dump_int("snap_id", snap_id);
+}
+
+void ImageSnapshotSpec::generate_test_instances(std::list<ImageSnapshotSpec *> &o) {
+  o.push_back(new ImageSnapshotSpec(0, "myimage", 2));
+  o.push_back(new ImageSnapshotSpec(1, "testimage", 7));
+}
+
+void GroupSnapshot::encode(bufferlist& bl) const {
+  using ceph::encode;
+  ENCODE_START(1, 1, bl);
+  encode(id, bl);
+  encode(name, bl);
+  encode(state, bl);
+  encode(snaps, bl);
+  ENCODE_FINISH(bl);
+}
+
+void GroupSnapshot::decode(bufferlist::const_iterator& it) {
+  using ceph::decode;
+  DECODE_START(1, it);
+  decode(id, it);
+  decode(name, it);
+  decode(state, it);
+  decode(snaps, it);
+  DECODE_FINISH(it);
+}
+
+void GroupSnapshot::dump(Formatter *f) const {
+  f->dump_string("id", id);
+  f->dump_string("name", name);
+  f->dump_int("state", state);
+}
+
+void GroupSnapshot::generate_test_instances(std::list<GroupSnapshot *> &o) {
+  o.push_back(new GroupSnapshot("10152ae8944a", "groupsnapshot1", GROUP_SNAPSHOT_STATE_INCOMPLETE));
+  o.push_back(new GroupSnapshot("1018643c9869", "groupsnapshot2", GROUP_SNAPSHOT_STATE_COMPLETE));
+}
+void TrashImageSpec::encode(bufferlist& bl) const {
+  ENCODE_START(2, 1, bl);
+  encode(source, bl);
+  encode(name, bl);
+  encode(deletion_time, bl);
+  encode(deferment_end_time, bl);
+  encode(state, bl);
+  ENCODE_FINISH(bl);
+}
+
+void TrashImageSpec::decode(bufferlist::const_iterator &it) {
+  DECODE_START(2, it);
+  decode(source, it);
+  decode(name, it);
+  decode(deletion_time, it);
+  decode(deferment_end_time, it);
+  if (struct_v >= 2) {
+    decode(state, it);
+  }
+  DECODE_FINISH(it);
+}
+
+void TrashImageSpec::dump(Formatter *f) const {
+  f->dump_stream("source") << source;
+  f->dump_string("name", name);
+  f->dump_unsigned("deletion_time", deletion_time);
+  f->dump_unsigned("deferment_end_time", deferment_end_time);
+}
+
+void MirrorImageMap::encode(bufferlist &bl) const {
+  ENCODE_START(1, 1, bl);
+  encode(instance_id, bl);
+  encode(mapped_time, bl);
+  encode(data, bl);
+  ENCODE_FINISH(bl);
+}
+
+void MirrorImageMap::decode(bufferlist::const_iterator &it) {
+  DECODE_START(1, it);
+  decode(instance_id, it);
+  decode(mapped_time, it);
+  decode(data, it);
+  DECODE_FINISH(it);
+}
+
+void MirrorImageMap::dump(Formatter *f) const {
+  f->dump_string("instance_id", instance_id);
+  f->dump_stream("mapped_time") << mapped_time;
+
+  std::stringstream data_ss;
+  data.hexdump(data_ss);
+  f->dump_string("data", data_ss.str());
+}
+
+void MirrorImageMap::generate_test_instances(
+  std::list<MirrorImageMap*> &o) {
+  bufferlist data;
+  data.append(std::string(128, '1'));
+
+  o.push_back(new MirrorImageMap("uuid-123", utime_t(), data));
+  o.push_back(new MirrorImageMap("uuid-abc", utime_t(), data));
+}
+
+bool MirrorImageMap::operator==(const MirrorImageMap &rhs) const {
+  return instance_id == rhs.instance_id && mapped_time == rhs.mapped_time &&
+    data.contents_equal(rhs.data);
+}
+
+bool MirrorImageMap::operator<(const MirrorImageMap &rhs) const {
+  return instance_id < rhs.instance_id ||
+        (instance_id == rhs.instance_id && mapped_time < rhs.mapped_time);
+}
+
+std::ostream& operator<<(std::ostream& os,
+                         const MirrorImageMap &image_map) {
+  return os << "[" << "instance_id=" << image_map.instance_id << ", mapped_time="
+            << image_map.mapped_time << "]";
+}
+
+std::ostream& operator<<(std::ostream& os,
+                         const MigrationHeaderType& type) {
+  switch (type) {
+  case MIGRATION_HEADER_TYPE_SRC:
+    os << "source";
+    break;
+  case MIGRATION_HEADER_TYPE_DST:
+    os << "destination";
+    break;
+  default:
+    os << "unknown (" << static_cast<uint32_t>(type) << ")";
+    break;
+  }
+  return os;
+}
+
+std::ostream& operator<<(std::ostream& os,
+                         const MigrationState& migration_state) {
+  switch (migration_state) {
+  case MIGRATION_STATE_ERROR:
+    os << "error";
+    break;
+  case MIGRATION_STATE_PREPARING:
+    os << "preparing";
+    break;
+  case MIGRATION_STATE_PREPARED:
+    os << "prepared";
+    break;
+  case MIGRATION_STATE_EXECUTING:
+    os << "executing";
+    break;
+  case MIGRATION_STATE_EXECUTED:
+    os << "executed";
+    break;
+  case MIGRATION_STATE_ABORTING:
+    os << "aborting";
+    break;
+  default:
+    os << "unknown (" << static_cast<uint32_t>(migration_state) << ")";
+    break;
+  }
+  return os;
+}
+
+void MigrationSpec::encode(bufferlist& bl) const {
+  uint8_t min_version = 1;
+  if (!source_spec.empty()) {
+    min_version = 3;
+  }
+
+  ENCODE_START(3, min_version, bl);
+  encode(header_type, bl);
+  encode(pool_id, bl);
+  encode(pool_namespace, bl);
+  encode(image_name, bl);
+  encode(image_id, bl);
+  encode(snap_seqs, bl);
+  encode(overlap, bl);
+  encode(flatten, bl);
+  encode(mirroring, bl);
+  encode(state, bl);
+  encode(state_description, bl);
+  encode(static_cast<uint8_t>(mirror_image_mode), bl);
+  encode(source_spec, bl);
+  ENCODE_FINISH(bl);
+}
+
+void MigrationSpec::decode(bufferlist::const_iterator& bl) {
+  DECODE_START(3, bl);
+  decode(header_type, bl);
+  decode(pool_id, bl);
+  decode(pool_namespace, bl);
+  decode(image_name, bl);
+  decode(image_id, bl);
+  decode(snap_seqs, bl);
+  decode(overlap, bl);
+  decode(flatten, bl);
+  decode(mirroring, bl);
+  decode(state, bl);
+  decode(state_description, bl);
+  if (struct_v >= 2) {
+    uint8_t int_mode;
+    decode(int_mode, bl);
+    mirror_image_mode = static_cast<MirrorImageMode>(int_mode);
+  }
+  if (struct_v >= 3) {
+    decode(source_spec, bl);
+  }
+  DECODE_FINISH(bl);
+}
+
+std::ostream& operator<<(std::ostream& os,
+                         const std::map<uint64_t, uint64_t>& snap_seqs) {
+  os << "{";
+  size_t count = 0;
+  for (auto &it : snap_seqs) {
+    os << (count++ > 0 ? ", " : "") << "(" << it.first << ", " << it.second
+       << ")";
+  }
+  os << "}";
+  return os;
+}
+
+void MigrationSpec::dump(Formatter *f) const {
+  f->dump_stream("header_type") << header_type;
+  if (header_type == MIGRATION_HEADER_TYPE_SRC ||
+      source_spec.empty()) {
+    f->dump_int("pool_id", pool_id);
+    f->dump_string("pool_namespace", pool_namespace);
+    f->dump_string("image_name", image_name);
+    f->dump_string("image_id", image_id);
+  } else {
+    f->dump_string("source_spec", source_spec);
+  }
+  f->dump_stream("snap_seqs") << snap_seqs;
+  f->dump_unsigned("overlap", overlap);
+  f->dump_bool("mirroring", mirroring);
+  f->dump_stream("mirror_image_mode") << mirror_image_mode;
+}
+
+void MigrationSpec::generate_test_instances(std::list<MigrationSpec*> &o) {
+  o.push_back(new MigrationSpec());
+  o.push_back(new MigrationSpec(MIGRATION_HEADER_TYPE_SRC, 1, "ns",
+                                "image_name", "image_id", "", {{1, 2}}, 123,
+                                true, MIRROR_IMAGE_MODE_SNAPSHOT, true,
+                                MIGRATION_STATE_PREPARED, "description"));
+  o.push_back(new MigrationSpec(MIGRATION_HEADER_TYPE_DST, -1, "", "", "",
+                                "{\"format\": \"raw\"}", {{1, 2}}, 123,
+                                true, MIRROR_IMAGE_MODE_SNAPSHOT, true,
+                                MIGRATION_STATE_PREPARED, "description"));
+}
+
+std::ostream& operator<<(std::ostream& os,
+                         const MigrationSpec& migration_spec) {
+  os << "["
+     << "header_type=" << migration_spec.header_type << ", ";
+  if (migration_spec.header_type == MIGRATION_HEADER_TYPE_SRC ||
+      migration_spec.source_spec.empty()) {
+    os << "pool_id=" << migration_spec.pool_id << ", "
+       << "pool_namespace=" << migration_spec.pool_namespace << ", "
+       << "image_name=" << migration_spec.image_name << ", "
+       << "image_id=" << migration_spec.image_id << ", ";
+  } else {
+     os << "source_spec=" << migration_spec.source_spec << ", ";
+  }
+  os << "snap_seqs=" << migration_spec.snap_seqs << ", "
+     << "overlap=" << migration_spec.overlap << ", "
+     << "flatten=" << migration_spec.flatten << ", "
+     << "mirroring=" << migration_spec.mirroring << ", "
+     << "mirror_image_mode=" << migration_spec.mirror_image_mode << ", "
+     << "state=" << migration_spec.state << ", "
+     << "state_description=" << migration_spec.state_description << "]";
+  return os;
+}
+
+std::ostream& operator<<(std::ostream& os, const AssertSnapcSeqState& state) {
+  switch (state) {
+  case ASSERT_SNAPC_SEQ_GT_SNAPSET_SEQ:
+    os << "gt";
+    break;
+  case ASSERT_SNAPC_SEQ_LE_SNAPSET_SEQ:
+    os << "le";
+    break;
+  default:
+    os << "unknown (" << static_cast<uint32_t>(state) << ")";
+    break;
+  }
+  return os;
+}
+
+void sanitize_entity_inst(entity_inst_t* entity_inst) {
+  // make all addrs of type ANY because the type isn't what uniquely
+  // identifies them and clients and on-disk formats can be encoded
+  // with different backwards compatibility settings.
+  entity_inst->addr.set_type(entity_addr_t::TYPE_ANY);
+}
+
+} // namespace rbd
+} // namespace cls
diff --git a/src/cls/rbd/cls_rbd_types.h b/src/cls/rbd/cls_rbd_types.h
new file mode 100644
index 000000000..645861b2d
--- /dev/null
+++ b/src/cls/rbd/cls_rbd_types.h
@@ -0,0 +1,1023 @@
+// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
+// vim: ts=8 sw=2 smarttab
+
+#ifndef CEPH_CLS_RBD_TYPES_H
+#define CEPH_CLS_RBD_TYPES_H
+
+#include <boost/variant.hpp>
+#include "include/int_types.h"
+#include "include/buffer.h"
+#include "include/encoding.h"
+#include "include/stringify.h"
+#include "include/utime.h"
+#include "msg/msg_types.h"
+#include <iosfwd>
+#include <string>
+#include <set>
+
+#define RBD_GROUP_REF "rbd_group_ref"
+
+namespace ceph { class Formatter; }
+
+namespace cls {
+namespace rbd {
+
+static const uint32_t MAX_OBJECT_MAP_OBJECT_COUNT = 256000000;
+static const std::string RBD_GROUP_IMAGE_KEY_PREFIX = "image_";
+
+enum DirectoryState {
+  DIRECTORY_STATE_READY         = 0,
+  DIRECTORY_STATE_ADD_DISABLED  = 1
+};
+
+inline void encode(DirectoryState state, ceph::buffer::list& bl,
+		   uint64_t features=0)
+{
+  ceph::encode(static_cast<uint8_t>(state), bl);
+}
+
+inline void decode(DirectoryState &state, ceph::buffer::list::const_iterator& it)
+{
+  uint8_t int_state;
+  ceph::decode(int_state, it);
+  state = static_cast<DirectoryState>(int_state);
+}
+
+enum MirrorMode {
+  MIRROR_MODE_DISABLED = 0,
+  MIRROR_MODE_IMAGE    = 1,
+  MIRROR_MODE_POOL     = 2
+};
+
+enum GroupImageLinkState {
+  GROUP_IMAGE_LINK_STATE_ATTACHED,
+  GROUP_IMAGE_LINK_STATE_INCOMPLETE
+};
+
+inline void encode(const GroupImageLinkState &state, ceph::buffer::list& bl,
+		   uint64_t features=0)
+{
+  using ceph::encode;
+  encode(static_cast<uint8_t>(state), bl);
+}
+
+inline void decode(GroupImageLinkState &state, ceph::buffer::list::const_iterator& it)
+{
+  uint8_t int_state;
+  using ceph::decode;
+  decode(int_state, it);
+  state = static_cast<GroupImageLinkState>(int_state);
+}
+
+enum MirrorPeerDirection {
+  MIRROR_PEER_DIRECTION_RX    = 0,
+  MIRROR_PEER_DIRECTION_TX    = 1,
+  MIRROR_PEER_DIRECTION_RX_TX = 2
+};
+
+std::ostream& operator<<(std::ostream& os,
+                         MirrorPeerDirection mirror_peer_direction);
+
+struct MirrorPeer {
+  MirrorPeer() {
+  }
+  MirrorPeer(const std::string &uuid,
+             MirrorPeerDirection mirror_peer_direction,
+             const std::string& site_name,
+             const std::string& client_name,
+             const std::string& mirror_uuid)
+    : uuid(uuid), mirror_peer_direction(mirror_peer_direction),
+      site_name(site_name), client_name(client_name),
+      mirror_uuid(mirror_uuid) {
+  }
+
+  std::string uuid;
+
+  MirrorPeerDirection mirror_peer_direction = MIRROR_PEER_DIRECTION_RX_TX;
+  std::string site_name;
+  std::string client_name;  // RX property
+  std::string mirror_uuid;
+  utime_t last_seen;
+
+  inline bool is_valid() const {
+    switch (mirror_peer_direction) {
+    case MIRROR_PEER_DIRECTION_TX:
+      break;
+    case MIRROR_PEER_DIRECTION_RX:
+    case MIRROR_PEER_DIRECTION_RX_TX:
+      if (client_name.empty()) {
+        return false;
+      }
+      break;
+    default:
+      return false;
+    }
+    return (!uuid.empty() && !site_name.empty());
+  }
+
+  void encode(ceph::buffer::list &bl) const;
+  void decode(ceph::buffer::list::const_iterator &it);
+  void dump(ceph::Formatter *f) const;
+
+  static void generate_test_instances(std::list<MirrorPeer*> &o);
+
+  bool operator==(const MirrorPeer &rhs) const;
+  bool operator!=(const MirrorPeer &rhs) const {
+    return (!(*this == rhs));
+  }
+};
+
+std::ostream& operator<<(std::ostream& os, const MirrorMode& mirror_mode);
+std::ostream& operator<<(std::ostream& os, const MirrorPeer& peer);
+
+WRITE_CLASS_ENCODER(MirrorPeer);
+
+enum MirrorImageMode {
+  MIRROR_IMAGE_MODE_JOURNAL  = 0,
+  MIRROR_IMAGE_MODE_SNAPSHOT = 1,
+};
+
+enum MirrorImageState {
+  MIRROR_IMAGE_STATE_DISABLING = 0,
+  MIRROR_IMAGE_STATE_ENABLED   = 1,
+  MIRROR_IMAGE_STATE_DISABLED  = 2,
+  MIRROR_IMAGE_STATE_CREATING  = 3,
+};
+
+struct MirrorImage {
+  MirrorImage() {
+  }
+  MirrorImage(MirrorImageMode mode, const std::string &global_image_id,
+              MirrorImageState state)
+    : mode(mode), global_image_id(global_image_id), state(state) {
+  }
+
+  MirrorImageMode mode = MIRROR_IMAGE_MODE_JOURNAL;
+  std::string global_image_id;
+  MirrorImageState state = MIRROR_IMAGE_STATE_DISABLING;
+
+  void encode(ceph::buffer::list &bl) const;
+  void decode(ceph::buffer::list::const_iterator &it);
+  void dump(ceph::Formatter *f) const;
+
+  static void generate_test_instances(std::list<MirrorImage*> &o);
+
+  bool operator==(const MirrorImage &rhs) const;
+  bool operator<(const MirrorImage &rhs) const;
+};
+
+std::ostream& operator<<(std::ostream& os, const MirrorImageMode& mirror_mode);
+std::ostream& operator<<(std::ostream& os, const MirrorImageState& mirror_state);
+std::ostream& operator<<(std::ostream& os, const MirrorImage& mirror_image);
+
+WRITE_CLASS_ENCODER(MirrorImage);
+
+enum MirrorImageStatusState {
+  MIRROR_IMAGE_STATUS_STATE_UNKNOWN         = 0,
+  MIRROR_IMAGE_STATUS_STATE_ERROR           = 1,
+  MIRROR_IMAGE_STATUS_STATE_SYNCING         = 2,
+  MIRROR_IMAGE_STATUS_STATE_STARTING_REPLAY = 3,
+  MIRROR_IMAGE_STATUS_STATE_REPLAYING       = 4,
+  MIRROR_IMAGE_STATUS_STATE_STOPPING_REPLAY = 5,
+  MIRROR_IMAGE_STATUS_STATE_STOPPED         = 6,
+};
+
+inline void encode(const MirrorImageStatusState &state, ceph::buffer::list& bl,
+		   uint64_t features=0)
+{
+  using ceph::encode;
+  encode(static_cast<uint8_t>(state), bl);
+}
+
+inline void decode(MirrorImageStatusState &state,
+                   ceph::buffer::list::const_iterator& it)
+{
+  uint8_t int_state;
+  using ceph::decode;
+  decode(int_state, it);
+  state = static_cast<MirrorImageStatusState>(int_state);
+}
+
+std::ostream& operator<<(std::ostream& os, const MirrorImageStatusState& state);
+
+struct MirrorImageSiteStatus {
+  static const std::string LOCAL_MIRROR_UUID;
+
+  MirrorImageSiteStatus() {}
+  MirrorImageSiteStatus(const std::string& mirror_uuid,
+                        MirrorImageStatusState state,
+                        const std::string &description)
+    : mirror_uuid(mirror_uuid), state(state), description(description) {
+  }
+
+  std::string mirror_uuid = LOCAL_MIRROR_UUID;
+  MirrorImageStatusState state = MIRROR_IMAGE_STATUS_STATE_UNKNOWN;
+  std::string description;
+  utime_t last_update;
+  bool up = false;
+
+  void encode_meta(uint8_t version, ceph::buffer::list &bl) const;
+  void decode_meta(uint8_t version, ceph::buffer::list::const_iterator &it);
+
+  void encode(ceph::buffer::list &bl) const;
+  void decode(ceph::buffer::list::const_iterator &it);
+  void dump(ceph::Formatter *f) const;
+
+  std::string state_to_string() const;
+
+  bool operator==(const MirrorImageSiteStatus &rhs) const;
+
+  static void generate_test_instances(std::list<MirrorImageSiteStatus*> &o);
+};
+WRITE_CLASS_ENCODER(MirrorImageSiteStatus);
+
+std::ostream& operator<<(std::ostream& os, const MirrorImageSiteStatus& status);
+
+struct MirrorImageSiteStatusOnDisk : cls::rbd::MirrorImageSiteStatus {
+  entity_inst_t origin;
+
+  MirrorImageSiteStatusOnDisk() {
+  }
+  MirrorImageSiteStatusOnDisk(const cls::rbd::MirrorImageSiteStatus &status) :
+    cls::rbd::MirrorImageSiteStatus(status) {
+  }
+
+  void encode_meta(ceph::buffer::list &bl, uint64_t features) const;
+  void decode_meta(ceph::buffer::list::const_iterator &it);
+
+  void encode(ceph::buffer::list &bl, uint64_t features) const;
+  void decode(ceph::buffer::list::const_iterator &it);
+
+  static void generate_test_instances(
+      std::list<MirrorImageSiteStatusOnDisk*> &o);
+};
+WRITE_CLASS_ENCODER_FEATURES(MirrorImageSiteStatusOnDisk)
+
+struct MirrorImageStatus {
+  typedef std::list<MirrorImageSiteStatus> MirrorImageSiteStatuses;
+
+  MirrorImageStatus() {}
+  MirrorImageStatus(const MirrorImageSiteStatuses& statuses)
+    : mirror_image_site_statuses(statuses) {
+  }
+
+  MirrorImageSiteStatuses mirror_image_site_statuses;
+
+  int get_local_mirror_image_site_status(MirrorImageSiteStatus* status) const;
+
+  void encode(ceph::buffer::list &bl) const;
+  void decode(ceph::buffer::list::const_iterator &it);
+  void dump(ceph::Formatter *f) const;
+
+  bool operator==(const MirrorImageStatus& rhs) const;
+
+  static void generate_test_instances(std::list<MirrorImageStatus*> &o);
+};
+WRITE_CLASS_ENCODER(MirrorImageStatus);
+
+std::ostream& operator<<(std::ostream& os, const MirrorImageStatus& status);
+
+struct ParentImageSpec {
+  int64_t pool_id = -1;
+  std::string pool_namespace;
+  std::string image_id;
+  snapid_t snap_id = CEPH_NOSNAP;
+
+  ParentImageSpec() {
+  }
+  ParentImageSpec(int64_t pool_id, const std::string& pool_namespace,
+                  const std::string& image_id, snapid_t snap_id)
+    : pool_id(pool_id), pool_namespace(pool_namespace), image_id(image_id),
+      snap_id(snap_id) {
+  }
+
+  bool exists() const {
+    return (pool_id >= 0 && !image_id.empty() && snap_id != CEPH_NOSNAP);
+  }
+
+  bool operator==(const ParentImageSpec& rhs) const {
+    return ((pool_id == rhs.pool_id) &&
+            (pool_namespace == rhs.pool_namespace) &&
+            (image_id == rhs.image_id) &&
+            (snap_id == rhs.snap_id));
+  }
+
+  bool operator!=(const ParentImageSpec& rhs) const {
+    return !(*this == rhs);
+  }
+
+  void encode(ceph::buffer::list &bl) const;
+  void decode(ceph::buffer::list::const_iterator &it);
+  void dump(ceph::Formatter *f) const;
+
+  static void generate_test_instances(std::list<ParentImageSpec*> &o);
+};
+
+WRITE_CLASS_ENCODER(ParentImageSpec);
+
+std::ostream& operator<<(std::ostream& os, const ParentImageSpec& rhs);
+
+struct ChildImageSpec {
+  int64_t pool_id = -1;
+  std::string pool_namespace;
+  std::string image_id;
+
+  ChildImageSpec() {}
+  ChildImageSpec(int64_t pool_id, const std::string& pool_namespace,
+                 const std::string& image_id)
+    : pool_id(pool_id), pool_namespace(pool_namespace), image_id(image_id) {
+  }
+
+  void encode(ceph::buffer::list &bl) const;
+  void decode(ceph::buffer::list::const_iterator &it);
+  void dump(ceph::Formatter *f) const;
+
+  static void generate_test_instances(std::list<ChildImageSpec*> &o);
+
+  inline bool operator==(const ChildImageSpec& rhs) const {
+    return (pool_id == rhs.pool_id &&
+            pool_namespace == rhs.pool_namespace &&
+            image_id == rhs.image_id);
+  }
+  inline bool operator<(const ChildImageSpec& rhs) const {
+    if (pool_id != rhs.pool_id) {
+      return pool_id < rhs.pool_id;
+    }
+    if (pool_namespace != rhs.pool_namespace) {
+      return pool_namespace < rhs.pool_namespace;
+    }
+    return image_id < rhs.image_id;
+  }
+};
+WRITE_CLASS_ENCODER(ChildImageSpec);
+
+std::ostream& operator<<(std::ostream& os, const ChildImageSpec& rhs);
+
+typedef std::set<ChildImageSpec> ChildImageSpecs;
+
+struct GroupImageSpec {
+  GroupImageSpec() {}
+
+  GroupImageSpec(const std::string &image_id, int64_t pool_id)
+    : image_id(image_id), pool_id(pool_id) {}
+
+  static int from_key(const std::string &image_key, GroupImageSpec *spec);
+
+  std::string image_id;
+  int64_t pool_id = -1;
+
+  void encode(ceph::buffer::list &bl) const;
+  void decode(ceph::buffer::list::const_iterator &it);
+  void dump(ceph::Formatter *f) const;
+
+  static void generate_test_instances(std::list<GroupImageSpec*> &o);
+
+  std::string image_key();
+
+};
+WRITE_CLASS_ENCODER(GroupImageSpec);
+
+struct GroupImageStatus {
+  GroupImageStatus() {}
+  GroupImageStatus(const std::string &image_id,
+		   int64_t pool_id,
+		   GroupImageLinkState state)
+    : spec(image_id, pool_id), state(state) {}
+
+  GroupImageStatus(GroupImageSpec spec,
+		   GroupImageLinkState state)
+    : spec(spec), state(state) {}
+
+  GroupImageSpec spec;
+  GroupImageLinkState state = GROUP_IMAGE_LINK_STATE_INCOMPLETE;
+
+  void encode(ceph::buffer::list &bl) const;
+  void decode(ceph::buffer::list::const_iterator &it);
+  void dump(ceph::Formatter *f) const;
+
+  static void generate_test_instances(std::list<GroupImageStatus*> &o);
+
+  std::string state_to_string() const;
+};
+
+WRITE_CLASS_ENCODER(GroupImageStatus);
+
+struct GroupSpec {
+  GroupSpec() {}
+  GroupSpec(const std::string &group_id, int64_t pool_id)
+    : group_id(group_id), pool_id(pool_id) {}
+
+  std::string group_id;
+  int64_t pool_id = -1;
+
+  void encode(ceph::buffer::list &bl) const;
+  void decode(ceph::buffer::list::const_iterator &it);
+  void dump(ceph::Formatter *f) const;
+  bool is_valid() const;
+
+  static void generate_test_instances(std::list<GroupSpec *> &o);
+};
+
+WRITE_CLASS_ENCODER(GroupSpec);
+
+enum SnapshotNamespaceType {
+  SNAPSHOT_NAMESPACE_TYPE_USER   = 0,
+  SNAPSHOT_NAMESPACE_TYPE_GROUP  = 1,
+  SNAPSHOT_NAMESPACE_TYPE_TRASH  = 2,
+  SNAPSHOT_NAMESPACE_TYPE_MIRROR = 3,
+};
+
+struct UserSnapshotNamespace {
+  static const SnapshotNamespaceType SNAPSHOT_NAMESPACE_TYPE =
+    SNAPSHOT_NAMESPACE_TYPE_USER;
+
+  UserSnapshotNamespace() {}
+
+  void encode(ceph::buffer::list& bl) const {}
+  void decode(ceph::buffer::list::const_iterator& it) {}
+
+  void dump(ceph::Formatter *f) const {}
+
+  inline bool operator==(const UserSnapshotNamespace& usn) const {
+    return true;
+  }
+
+  inline bool operator<(const UserSnapshotNamespace& usn) const {
+    return false;
+  }
+};
+
+struct GroupSnapshotNamespace {
+  static const SnapshotNamespaceType SNAPSHOT_NAMESPACE_TYPE =
+    SNAPSHOT_NAMESPACE_TYPE_GROUP;
+
+  GroupSnapshotNamespace() {}
+
+  GroupSnapshotNamespace(int64_t _group_pool,
+			 const std::string &_group_id,
+			 const std::string &_group_snapshot_id)
+    : group_id(_group_id), group_pool(_group_pool),
+      group_snapshot_id(_group_snapshot_id) {}
+
+  std::string group_id;
+  int64_t group_pool = 0;
+  std::string group_snapshot_id;
+
+  void encode(ceph::buffer::list& bl) const;
+  void decode(ceph::buffer::list::const_iterator& it);
+
+  void dump(ceph::Formatter *f) const;
+
+  inline bool operator==(const GroupSnapshotNamespace& gsn) const {
+    return group_pool == gsn.group_pool &&
+	   group_id == gsn.group_id &&
+	   group_snapshot_id == gsn.group_snapshot_id;
+  }
+
+  inline bool operator<(const GroupSnapshotNamespace& gsn) const {
+    if (group_pool != gsn.group_pool) {
+      return group_pool < gsn.group_pool;
+    }
+    if (group_id != gsn.group_id) {
+      return group_id < gsn.group_id;
+    }
+    return group_snapshot_id < gsn.group_snapshot_id;
+  }
+};
+
+struct TrashSnapshotNamespace {
+  static const SnapshotNamespaceType SNAPSHOT_NAMESPACE_TYPE =
+    SNAPSHOT_NAMESPACE_TYPE_TRASH;
+
+  std::string original_name;
+  SnapshotNamespaceType original_snapshot_namespace_type =
+    SNAPSHOT_NAMESPACE_TYPE_USER;
+
+  TrashSnapshotNamespace() {}
+  TrashSnapshotNamespace(SnapshotNamespaceType original_snapshot_namespace_type,
+                         const std::string& original_name)
+    : original_name(original_name),
+      original_snapshot_namespace_type(original_snapshot_namespace_type) {}
+
+  void encode(ceph::buffer::list& bl) const;
+  void decode(ceph::buffer::list::const_iterator& it);
+  void dump(ceph::Formatter *f) const;
+
+  inline bool operator==(const TrashSnapshotNamespace& usn) const {
+    return true;
+  }
+  inline bool operator<(const TrashSnapshotNamespace& usn) const {
+    return false;
+  }
+};
+
+enum MirrorSnapshotState {
+  MIRROR_SNAPSHOT_STATE_PRIMARY             = 0,
+  MIRROR_SNAPSHOT_STATE_PRIMARY_DEMOTED     = 1,
+  MIRROR_SNAPSHOT_STATE_NON_PRIMARY         = 2,
+  MIRROR_SNAPSHOT_STATE_NON_PRIMARY_DEMOTED = 3,
+};
+
+inline void encode(const MirrorSnapshotState &state, ceph::buffer::list& bl,
+                   uint64_t features=0) {
+  using ceph::encode;
+  encode(static_cast<uint8_t>(state), bl);
+}
+
+inline void decode(MirrorSnapshotState &state, ceph::buffer::list::const_iterator& it) {
+  using ceph::decode;
+  uint8_t int_state;
+  decode(int_state, it);
+  state = static_cast<MirrorSnapshotState>(int_state);
+}
+
+std::ostream& operator<<(std::ostream& os, MirrorSnapshotState type);
+
+typedef std::map<uint64_t, uint64_t> SnapSeqs;
+
+struct MirrorSnapshotNamespace {
+  static const SnapshotNamespaceType SNAPSHOT_NAMESPACE_TYPE =
+    SNAPSHOT_NAMESPACE_TYPE_MIRROR;
+
+  MirrorSnapshotState state = MIRROR_SNAPSHOT_STATE_NON_PRIMARY;
+  bool complete = false;
+  std::set<std::string> mirror_peer_uuids;
+
+  std::string primary_mirror_uuid;
+  union {
+    snapid_t primary_snap_id = CEPH_NOSNAP;
+    snapid_t clean_since_snap_id;
+  };
+  uint64_t last_copied_object_number = 0;
+  SnapSeqs snap_seqs;
+
+  MirrorSnapshotNamespace() {
+  }
+  MirrorSnapshotNamespace(MirrorSnapshotState state,
+                          const std::set<std::string> &mirror_peer_uuids,
+                          const std::string& primary_mirror_uuid,
+                          snapid_t primary_snap_id)
+    : state(state), mirror_peer_uuids(mirror_peer_uuids),
+      primary_mirror_uuid(primary_mirror_uuid),
+      primary_snap_id(primary_snap_id) {
+  }
+  MirrorSnapshotNamespace(MirrorSnapshotState state,
+                          const std::set<std::string> &mirror_peer_uuids,
+                          const std::string& primary_mirror_uuid,
+                          snapid_t primary_snap_id,
+                          bool complete,
+                          uint64_t last_copied_object_number,
+                          const SnapSeqs& snap_seqs)
+    : state(state), complete(complete), mirror_peer_uuids(mirror_peer_uuids),
+      primary_mirror_uuid(primary_mirror_uuid),
+      primary_snap_id(primary_snap_id),
+      last_copied_object_number(last_copied_object_number),
+      snap_seqs(snap_seqs) {
+  }
+
+  inline bool is_primary() const {
+    return (state == MIRROR_SNAPSHOT_STATE_PRIMARY ||
+            state == MIRROR_SNAPSHOT_STATE_PRIMARY_DEMOTED);
+  }
+
+  inline bool is_non_primary() const {
+    return (state == MIRROR_SNAPSHOT_STATE_NON_PRIMARY ||
+            state == MIRROR_SNAPSHOT_STATE_NON_PRIMARY_DEMOTED);
+  }
+
+  inline bool is_demoted() const {
+    return (state == MIRROR_SNAPSHOT_STATE_PRIMARY_DEMOTED ||
+            state == MIRROR_SNAPSHOT_STATE_NON_PRIMARY_DEMOTED);
+  }
+
+  inline bool is_orphan() const {
+    return (is_non_primary() &&
+            primary_mirror_uuid.empty() &&
+            primary_snap_id == CEPH_NOSNAP);
+  }
+
+  void encode(ceph::buffer::list& bl) const;
+  void decode(ceph::buffer::list::const_iterator& it);
+
+  void dump(ceph::Formatter *f) const;
+
+  inline bool operator==(const MirrorSnapshotNamespace& rhs) const {
+    return state == rhs.state &&
+           complete == rhs.complete &&
+           mirror_peer_uuids == rhs.mirror_peer_uuids &&
+           primary_mirror_uuid == rhs.primary_mirror_uuid &&
+           primary_snap_id == rhs.primary_snap_id &&
+           last_copied_object_number == rhs.last_copied_object_number &&
+           snap_seqs == rhs.snap_seqs;
+  }
+
+  inline bool operator<(const MirrorSnapshotNamespace& rhs) const {
+    if (state != rhs.state) {
+      return state < rhs.state;
+    } else if (complete != rhs.complete) {
+      return complete < rhs.complete;
+    } else if (mirror_peer_uuids != rhs.mirror_peer_uuids) {
+      return mirror_peer_uuids < rhs.mirror_peer_uuids;
+    } else if (primary_mirror_uuid != rhs.primary_mirror_uuid) {
+      return primary_mirror_uuid < rhs.primary_mirror_uuid;
+    } else if (primary_snap_id != rhs.primary_snap_id) {
+      return primary_snap_id < rhs.primary_snap_id;
+    } else if (last_copied_object_number != rhs.last_copied_object_number) {
+      return last_copied_object_number < rhs.last_copied_object_number;
+    } else {
+      return snap_seqs < rhs.snap_seqs;
+    }
+  }
+};
+
+struct UnknownSnapshotNamespace {
+  static const SnapshotNamespaceType SNAPSHOT_NAMESPACE_TYPE =
+    static_cast<SnapshotNamespaceType>(-1);
+
+  UnknownSnapshotNamespace() {}
+
+  void encode(ceph::buffer::list& bl) const {}
+  void decode(ceph::buffer::list::const_iterator& it) {}
+  void dump(ceph::Formatter *f) const {}
+
+  inline bool operator==(const UnknownSnapshotNamespace& gsn) const {
+    return true;
+  }
+
+  inline bool operator<(const UnknownSnapshotNamespace& gsn) const {
+    return false;
+  }
+};
+
+std::ostream& operator<<(std::ostream& os, const SnapshotNamespaceType& type);
+std::ostream& operator<<(std::ostream& os, const UserSnapshotNamespace& ns);
+std::ostream& operator<<(std::ostream& os, const GroupSnapshotNamespace& ns);
+std::ostream& operator<<(std::ostream& os, const TrashSnapshotNamespace& ns);
+std::ostream& operator<<(std::ostream& os, const MirrorSnapshotNamespace& ns);
+std::ostream& operator<<(std::ostream& os, const UnknownSnapshotNamespace& ns);
+
+typedef boost::variant<UserSnapshotNamespace,
+                       GroupSnapshotNamespace,
+                       TrashSnapshotNamespace,
+                       MirrorSnapshotNamespace,
+                       UnknownSnapshotNamespace> SnapshotNamespaceVariant;
+
+struct SnapshotNamespace : public SnapshotNamespaceVariant {
+  SnapshotNamespace() {
+  }
+
+  template <typename T>
+  SnapshotNamespace(T&& t) : SnapshotNamespaceVariant(std::forward<T>(t)) {
+  }
+
+  void encode(ceph::buffer::list& bl) const;
+  void decode(ceph::buffer::list::const_iterator& it);
+  void dump(ceph::Formatter *f) const;
+
+  static void generate_test_instances(std::list<SnapshotNamespace*> &o);
+
+  inline bool operator==(const SnapshotNamespaceVariant& sn) const {
+    return static_cast<const SnapshotNamespaceVariant&>(*this) == sn;
+  }
+  inline bool operator<(const SnapshotNamespaceVariant& sn) const {
+    return static_cast<const SnapshotNamespaceVariant&>(*this) < sn;
+  }
+  inline bool operator!=(const SnapshotNamespaceVariant& sn) const {
+    return !(*this == sn);
+  }
+};
+WRITE_CLASS_ENCODER(SnapshotNamespace);
+
+SnapshotNamespaceType get_snap_namespace_type(
+    const SnapshotNamespace& snapshot_namespace);
+
+struct SnapshotInfo {
+  snapid_t id = CEPH_NOSNAP;
+  cls::rbd::SnapshotNamespace snapshot_namespace = {UserSnapshotNamespace{}};
+  std::string name;
+  uint64_t image_size = 0;
+  utime_t timestamp;
+  uint32_t child_count = 0;
+
+  SnapshotInfo() {
+  }
+  SnapshotInfo(snapid_t id,
+               const cls::rbd::SnapshotNamespace& snapshot_namespace,
+               const std::string& name, uint64_t image_size,
+               const utime_t& timestamp, uint32_t child_count)
+    : id(id), snapshot_namespace(snapshot_namespace),
+      name(name), image_size(image_size), timestamp(timestamp),
+      child_count(child_count) {
+  }
+
+  void encode(ceph::buffer::list& bl) const;
+  void decode(ceph::buffer::list::const_iterator& it);
+  void dump(ceph::Formatter *f) const;
+
+  static void generate_test_instances(std::list<SnapshotInfo*> &o);
+};
+WRITE_CLASS_ENCODER(SnapshotInfo);
+
+enum GroupSnapshotState {
+  GROUP_SNAPSHOT_STATE_INCOMPLETE = 0,
+  GROUP_SNAPSHOT_STATE_COMPLETE = 1,
+};
+
+inline void encode(const GroupSnapshotState &state, ceph::buffer::list& bl, uint64_t features=0)
+{
+  using ceph::encode;
+  encode(static_cast<uint8_t>(state), bl);
+}
+
+inline void decode(GroupSnapshotState &state, ceph::buffer::list::const_iterator& it)
+{
+  using ceph::decode;
+  uint8_t int_state;
+  decode(int_state, it);
+  state = static_cast<GroupSnapshotState>(int_state);
+}
+
+struct ImageSnapshotSpec {
+  int64_t pool;
+  std::string image_id;
+  snapid_t snap_id;
+
+  ImageSnapshotSpec() {}
+  ImageSnapshotSpec(int64_t _pool,
+		    std::string _image_id,
+		    snapid_t _snap_id) : pool(_pool),
+					 image_id(_image_id),
+					 snap_id(_snap_id) {}
+
+  void encode(ceph::buffer::list& bl) const;
+  void decode(ceph::buffer::list::const_iterator& it);
+
+  void dump(ceph::Formatter *f) const;
+
+  static void generate_test_instances(std::list<ImageSnapshotSpec *> &o);
+};
+WRITE_CLASS_ENCODER(ImageSnapshotSpec);
+
+struct GroupSnapshot {
+  std::string id;
+  std::string name;
+  GroupSnapshotState state = GROUP_SNAPSHOT_STATE_INCOMPLETE;
+
+  GroupSnapshot() {}
+  GroupSnapshot(std::string _id,
+		std::string _name,
+		GroupSnapshotState _state) : id(_id),
+					     name(_name),
+					     state(_state) {}
+
+  std::vector<ImageSnapshotSpec> snaps;
+
+  void encode(ceph::buffer::list& bl) const;
+  void decode(ceph::buffer::list::const_iterator& it);
+  void dump(ceph::Formatter *f) const;
+
+  static void generate_test_instances(std::list<GroupSnapshot *> &o);
+};
+WRITE_CLASS_ENCODER(GroupSnapshot);
+enum TrashImageSource {
+  TRASH_IMAGE_SOURCE_USER = 0,
+  TRASH_IMAGE_SOURCE_MIRRORING = 1,
+  TRASH_IMAGE_SOURCE_MIGRATION = 2,
+  TRASH_IMAGE_SOURCE_REMOVING = 3,
+  TRASH_IMAGE_SOURCE_USER_PARENT= 4,
+};
+
+inline std::ostream& operator<<(std::ostream& os,
+                                const TrashImageSource& source) {
+  switch (source) {
+  case TRASH_IMAGE_SOURCE_USER:
+    os << "user";
+    break;
+  case TRASH_IMAGE_SOURCE_MIRRORING:
+    os << "mirroring";
+    break;
+  case TRASH_IMAGE_SOURCE_MIGRATION:
+    os << "migration";
+    break;
+  case TRASH_IMAGE_SOURCE_REMOVING:
+    os << "removing";
+    break;
+  default:
+    os << "unknown (" << static_cast<uint32_t>(source) << ")";
+    break;
+  }
+  return os;
+}
+
+inline void encode(const TrashImageSource &source, ceph::buffer::list& bl,
+		   uint64_t features=0)
+{
+  using ceph::encode;
+  encode(static_cast<uint8_t>(source), bl);
+}
+
+inline void decode(TrashImageSource &source, ceph::buffer::list::const_iterator& it)
+{
+  uint8_t int_source;
+  using ceph::decode;
+  decode(int_source, it);
+  source = static_cast<TrashImageSource>(int_source);
+}
+
+enum TrashImageState {
+  TRASH_IMAGE_STATE_NORMAL    = 0,
+  TRASH_IMAGE_STATE_MOVING    = 1,
+  TRASH_IMAGE_STATE_REMOVING  = 2,
+  TRASH_IMAGE_STATE_RESTORING = 3
+};
+
+inline void encode(const TrashImageState &state, ceph::buffer::list &bl)
+{
+  using ceph::encode;
+  encode(static_cast<uint8_t>(state), bl);
+}
+
+inline void decode(TrashImageState &state, ceph::buffer::list::const_iterator &it)
+{
+  uint8_t int_state;
+  using ceph::decode;
+  decode(int_state, it);
+  state = static_cast<TrashImageState>(int_state);
+}
+
+struct TrashImageSpec {
+  TrashImageSource source = TRASH_IMAGE_SOURCE_USER;
+  std::string name;
+  utime_t deletion_time; // time of deletion
+  utime_t deferment_end_time;
+  TrashImageState state = TRASH_IMAGE_STATE_NORMAL;
+
+  TrashImageSpec() {}
+  TrashImageSpec(TrashImageSource source, const std::string &name,
+                 const utime_t& deletion_time,
+                 const utime_t& deferment_end_time)
+    : source(source), name(name), deletion_time(deletion_time),
+      deferment_end_time(deferment_end_time) {
+  }
+
+  void encode(ceph::buffer::list &bl) const;
+  void decode(ceph::buffer::list::const_iterator& it);
+  void dump(ceph::Formatter *f) const;
+
+  inline bool operator==(const TrashImageSpec& rhs) const {
+    return (source == rhs.source &&
+            name == rhs.name &&
+            deletion_time == rhs.deletion_time &&
+            deferment_end_time == rhs.deferment_end_time);
+  }
+};
+WRITE_CLASS_ENCODER(TrashImageSpec);
+
+struct MirrorImageMap {
+  MirrorImageMap() {
+  }
+
+  MirrorImageMap(const std::string &instance_id, utime_t mapped_time,
+                 const ceph::buffer::list &data)
+    : instance_id(instance_id),
+      mapped_time(mapped_time),
+      data(data) {
+  }
+
+  std::string instance_id;
+  utime_t mapped_time;
+  ceph::buffer::list data;
+
+  void encode(ceph::buffer::list &bl) const;
+  void decode(ceph::buffer::list::const_iterator &it);
+  void dump(ceph::Formatter *f) const;
+
+  static void generate_test_instances(std::list<MirrorImageMap*> &o);
+
+  bool operator==(const MirrorImageMap &rhs) const;
+  bool operator<(const MirrorImageMap &rhs) const;
+};
+
+std::ostream& operator<<(std::ostream& os, const MirrorImageMap &image_map);
+
+WRITE_CLASS_ENCODER(MirrorImageMap);
+
+enum MigrationHeaderType {
+  MIGRATION_HEADER_TYPE_SRC = 1,
+  MIGRATION_HEADER_TYPE_DST = 2,
+};
+
+inline void encode(const MigrationHeaderType &type, ceph::buffer::list& bl) {
+  using ceph::encode;
+  encode(static_cast<uint8_t>(type), bl);
+}
+
+inline void decode(MigrationHeaderType &type, ceph::buffer::list::const_iterator& it) {
+  uint8_t int_type;
+  using ceph::decode;
+  decode(int_type, it);
+  type = static_cast<MigrationHeaderType>(int_type);
+}
+
+enum MigrationState {
+  MIGRATION_STATE_ERROR = 0,
+  MIGRATION_STATE_PREPARING = 1,
+  MIGRATION_STATE_PREPARED = 2,
+  MIGRATION_STATE_EXECUTING = 3,
+  MIGRATION_STATE_EXECUTED = 4,
+  MIGRATION_STATE_ABORTING = 5,
+};
+
+inline void encode(const MigrationState &state, ceph::buffer::list& bl) {
+  using ceph::encode;
+  encode(static_cast<uint8_t>(state), bl);
+}
+
+inline void decode(MigrationState &state, ceph::buffer::list::const_iterator& it) {
+  uint8_t int_state;
+  using ceph::decode;
+  decode(int_state, it);
+  state = static_cast<MigrationState>(int_state);
+}
+
+std::ostream& operator<<(std::ostream& os,
+                         const MigrationState& migration_state);
+
+struct MigrationSpec {
+  MigrationHeaderType header_type = MIGRATION_HEADER_TYPE_SRC;
+  int64_t pool_id = -1;
+  std::string pool_namespace;
+  std::string image_name;
+  std::string image_id;
+  std::string source_spec;
+  std::map<uint64_t, uint64_t> snap_seqs;
+  uint64_t overlap = 0;
+  bool flatten = false;
+  bool mirroring = false;
+  MirrorImageMode mirror_image_mode = MIRROR_IMAGE_MODE_JOURNAL;
+  MigrationState state = MIGRATION_STATE_ERROR;
+  std::string state_description;
+
+  MigrationSpec() {
+  }
+  MigrationSpec(MigrationHeaderType header_type, int64_t pool_id,
+                const std::string& pool_namespace,
+                const std::string& image_name, const std::string &image_id,
+                const std::string& source_spec,
+                const std::map<uint64_t, uint64_t> &snap_seqs, uint64_t overlap,
+                bool mirroring, MirrorImageMode mirror_image_mode, bool flatten,
+                MigrationState state, const std::string &state_description)
+    : header_type(header_type), pool_id(pool_id),
+      pool_namespace(pool_namespace), image_name(image_name),
+      image_id(image_id), source_spec(source_spec), snap_seqs(snap_seqs),
+      overlap(overlap), flatten(flatten), mirroring(mirroring),
+      mirror_image_mode(mirror_image_mode), state(state),
+      state_description(state_description) {
+  }
+
+  void encode(ceph::buffer::list &bl) const;
+  void decode(ceph::buffer::list::const_iterator& it);
+  void dump(ceph::Formatter *f) const;
+
+  static void generate_test_instances(std::list<MigrationSpec*> &o);
+
+  inline bool operator==(const MigrationSpec& ms) const {
+    return header_type == ms.header_type && pool_id == ms.pool_id &&
+      pool_namespace == ms.pool_namespace && image_name == ms.image_name &&
+      image_id == ms.image_id && source_spec == ms.source_spec &&
+      snap_seqs == ms.snap_seqs && overlap == ms.overlap &&
+      flatten == ms.flatten && mirroring == ms.mirroring &&
+      mirror_image_mode == ms.mirror_image_mode && state == ms.state &&
+      state_description == ms.state_description;
+  }
+};
+
+std::ostream& operator<<(std::ostream& os, const MigrationSpec& migration_spec);
+
+WRITE_CLASS_ENCODER(MigrationSpec);
+
+enum AssertSnapcSeqState {
+  ASSERT_SNAPC_SEQ_GT_SNAPSET_SEQ = 0,
+  ASSERT_SNAPC_SEQ_LE_SNAPSET_SEQ = 1,
+};
+
+inline void encode(const AssertSnapcSeqState &state, ceph::buffer::list& bl) {
+  using ceph::encode;
+  encode(static_cast<uint8_t>(state), bl);
+}
+
+inline void decode(AssertSnapcSeqState &state, ceph::buffer::list::const_iterator& it) {
+  uint8_t int_state;
+  using ceph::decode;
+  decode(int_state, it);
+  state = static_cast<AssertSnapcSeqState>(int_state);
+}
+
+std::ostream& operator<<(std::ostream& os, const AssertSnapcSeqState& state);
+
+void sanitize_entity_inst(entity_inst_t* entity_inst);
+
+} // namespace rbd
+} // namespace cls
+
+#endif // CEPH_CLS_RBD_TYPES_H