update sources to v12.2.1

[ceph.git] / ceph / src / librbd / internal.cc

// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
// vim: ts=8 sw=2 smarttab
#include "include/int_types.h"

#include <errno.h>
#include <limits.h>

#include "include/types.h"
#include "include/uuid.h"
#include "common/ceph_context.h"
#include "common/dout.h"
#include "common/errno.h"
#include "common/Throttle.h"
#include "common/event_socket.h"
#include "cls/lock/cls_lock_client.h"
#include "include/stringify.h"

#include "cls/rbd/cls_rbd.h"
#include "cls/rbd/cls_rbd_types.h"
#include "cls/rbd/cls_rbd_client.h"
#include "cls/journal/cls_journal_types.h"
#include "cls/journal/cls_journal_client.h"

#include "librbd/ExclusiveLock.h"
#include "librbd/ImageCtx.h"
#include "librbd/ImageState.h"
#include "librbd/internal.h"
#include "librbd/Journal.h"
#include "librbd/ObjectMap.h"
#include "librbd/Operations.h"
#include "librbd/Types.h"
#include "librbd/Utils.h"
#include "librbd/api/Image.h"
#include "librbd/exclusive_lock/AutomaticPolicy.h"
#include "librbd/exclusive_lock/StandardPolicy.h"
#include "librbd/image/CloneRequest.h"
#include "librbd/image/CreateRequest.h"
#include "librbd/image/RemoveRequest.h"
#include "librbd/io/AioCompletion.h"
#include "librbd/io/ImageRequest.h"
#include "librbd/io/ImageRequestWQ.h"
#include "librbd/io/ObjectRequest.h"
#include "librbd/io/ReadResult.h"
#include "librbd/journal/Types.h"
#include "librbd/managed_lock/Types.h"
#include "librbd/mirror/EnableRequest.h"
#include "librbd/operation/TrimRequest.h"

#include "journal/Journaler.h"

#include <boost/scope_exit.hpp>
#include <boost/variant.hpp>
#include "include/assert.h"

#define dout_subsys ceph_subsys_rbd
#undef dout_prefix
#define dout_prefix *_dout << "librbd: "

#define rbd_howmany(x, y)  (((x) + (y) - 1) / (y))

using std::map;
using std::pair;
using std::set;
using std::string;
using std::vector;
// list binds to list() here, so std::list is explicitly used below

using ceph::bufferlist;
using librados::snap_t;
using librados::IoCtx;
using librados::Rados;

namespace librbd {

namespace {

int validate_pool(IoCtx &io_ctx, CephContext *cct) {
  if (!cct->_conf->get_val<bool>("rbd_validate_pool")) {
    return 0;
  }

  int r = io_ctx.stat(RBD_DIRECTORY, NULL, NULL);
  if (r == 0) {
    return 0;
  } else if (r < 0 && r != -ENOENT) {
    lderr(cct) << "failed to stat RBD directory: " << cpp_strerror(r) << dendl;
    return r;
  }

  // allocate a self-managed snapshot id if this a new pool to force
  // self-managed snapshot mode
  uint64_t snap_id;
  r = io_ctx.selfmanaged_snap_create(&snap_id);
  if (r == -EINVAL) {
    lderr(cct) << "pool not configured for self-managed RBD snapshot support"
               << dendl;
    return r;
  } else if (r < 0) {
    lderr(cct) << "failed to allocate self-managed snapshot: "
               << cpp_strerror(r) << dendl;
    return r;
  }

  r = io_ctx.selfmanaged_snap_remove(snap_id);
  if (r < 0) {
    lderr(cct) << "failed to release self-managed snapshot " << snap_id
               << ": " << cpp_strerror(r) << dendl;
  }
  return 0;
}


} // anonymous namespace

  int detect_format(IoCtx &io_ctx, const string &name,
		    bool *old_format, uint64_t *size)
  {
    CephContext *cct = (CephContext *)io_ctx.cct();
    if (old_format)
      *old_format = true;
    int r = io_ctx.stat(util::old_header_name(name), size, NULL);
    if (r == -ENOENT) {
      if (old_format)
	*old_format = false;
      r = io_ctx.stat(util::id_obj_name(name), size, NULL);
      if (r < 0)
	return r;
    } else if (r < 0) {
      return r;
    }

    ldout(cct, 20) << "detect format of " << name << " : "
		   << (old_format ? (*old_format ? "old" : "new") :
		       "don't care")  << dendl;
    return 0;
  }

  bool has_parent(int64_t parent_pool_id, uint64_t off, uint64_t overlap)
  {
    return (parent_pool_id != -1 && off <= overlap);
  }

  void init_rbd_header(struct rbd_obj_header_ondisk& ondisk,
		       uint64_t size, int order, uint64_t bid)
  {
    uint32_t hi = bid >> 32;
    uint32_t lo = bid & 0xFFFFFFFF;
    uint32_t extra = rand() % 0xFFFFFFFF;
    memset(&ondisk, 0, sizeof(ondisk));

    memcpy(&ondisk.text, RBD_HEADER_TEXT, sizeof(RBD_HEADER_TEXT));
    memcpy(&ondisk.signature, RBD_HEADER_SIGNATURE,
	   sizeof(RBD_HEADER_SIGNATURE));
    memcpy(&ondisk.version, RBD_HEADER_VERSION, sizeof(RBD_HEADER_VERSION));

    snprintf(ondisk.block_name, sizeof(ondisk.block_name), "rb.%x.%x.%x",
	     hi, lo, extra);

    ondisk.image_size = size;
    ondisk.options.order = order;
    ondisk.options.crypt_type = RBD_CRYPT_NONE;
    ondisk.options.comp_type = RBD_COMP_NONE;
    ondisk.snap_seq = 0;
    ondisk.snap_count = 0;
    ondisk.reserved = 0;
    ondisk.snap_names_len = 0;
  }

  void image_info(ImageCtx *ictx, image_info_t& info, size_t infosize)
  {
    int obj_order = ictx->order;
    ictx->snap_lock.get_read();
    info.size = ictx->get_image_size(ictx->snap_id);
    ictx->snap_lock.put_read();
    info.obj_size = 1ULL << obj_order;
    info.num_objs = Striper::get_num_objects(ictx->layout, info.size);
    info.order = obj_order;
    strncpy(info.block_name_prefix, ictx->object_prefix.c_str(),
            RBD_MAX_BLOCK_NAME_SIZE);
    info.block_name_prefix[RBD_MAX_BLOCK_NAME_SIZE - 1] = '\0';

    // clear deprecated fields
    info.parent_pool = -1L;
    info.parent_name[0] = '\0';
  }

  uint64_t oid_to_object_no(const string& oid, const string& object_prefix)
  {
    istringstream iss(oid);
    // skip object prefix and separator
    iss.ignore(object_prefix.length() + 1);
    uint64_t num;
    iss >> std::hex >> num;
    return num;
  }

  void trim_image(ImageCtx *ictx, uint64_t newsize, ProgressContext& prog_ctx)
  {
    assert(ictx->owner_lock.is_locked());
    assert(ictx->exclusive_lock == nullptr ||
	   ictx->exclusive_lock->is_lock_owner());

    C_SaferCond ctx;
    ictx->snap_lock.get_read();
    operation::TrimRequest<> *req = operation::TrimRequest<>::create(
      *ictx, &ctx, ictx->size, newsize, prog_ctx);
    ictx->snap_lock.put_read();
    req->send();

    int r = ctx.wait();
    if (r < 0) {
      lderr(ictx->cct) << "warning: failed to remove some object(s): "
		       << cpp_strerror(r) << dendl;
    }
  }

  int read_header_bl(IoCtx& io_ctx, const string& header_oid,
		     bufferlist& header, uint64_t *ver)
  {
    int r;
    uint64_t off = 0;
#define READ_SIZE 4096
    do {
      bufferlist bl;
      r = io_ctx.read(header_oid, bl, READ_SIZE, off);
      if (r < 0)
	return r;
      header.claim_append(bl);
      off += r;
    } while (r == READ_SIZE);

    if (header.length() < sizeof(RBD_HEADER_TEXT) ||
	memcmp(RBD_HEADER_TEXT, header.c_str(), sizeof(RBD_HEADER_TEXT))) {
      CephContext *cct = (CephContext *)io_ctx.cct();
      lderr(cct) << "unrecognized header format" << dendl;
      return -ENXIO;
    }

    if (ver)
      *ver = io_ctx.get_last_version();

    return 0;
  }

  int read_header(IoCtx& io_ctx, const string& header_oid,
		  struct rbd_obj_header_ondisk *header, uint64_t *ver)
  {
    bufferlist header_bl;
    int r = read_header_bl(io_ctx, header_oid, header_bl, ver);
    if (r < 0)
      return r;
    if (header_bl.length() < (int)sizeof(*header))
      return -EIO;
    memcpy(header, header_bl.c_str(), sizeof(*header));

    return 0;
  }

  int tmap_set(IoCtx& io_ctx, const string& imgname)
  {
    bufferlist cmdbl, emptybl;
    __u8 c = CEPH_OSD_TMAP_SET;
    ::encode(c, cmdbl);
    ::encode(imgname, cmdbl);
    ::encode(emptybl, cmdbl);
    return io_ctx.tmap_update(RBD_DIRECTORY, cmdbl);
  }

  int tmap_rm(IoCtx& io_ctx, const string& imgname)
  {
    bufferlist cmdbl;
    __u8 c = CEPH_OSD_TMAP_RM;
    ::encode(c, cmdbl);
    ::encode(imgname, cmdbl);
    return io_ctx.tmap_update(RBD_DIRECTORY, cmdbl);
  }

  typedef boost::variant<std::string,uint64_t> image_option_value_t;
  typedef std::map<int,image_option_value_t> image_options_t;
  typedef std::shared_ptr<image_options_t> image_options_ref;

  enum image_option_type_t {
    STR,
    UINT64,
  };

  const std::map<int, image_option_type_t> IMAGE_OPTIONS_TYPE_MAPPING = {
    {RBD_IMAGE_OPTION_FORMAT, UINT64},
    {RBD_IMAGE_OPTION_FEATURES, UINT64},
    {RBD_IMAGE_OPTION_ORDER, UINT64},
    {RBD_IMAGE_OPTION_STRIPE_UNIT, UINT64},
    {RBD_IMAGE_OPTION_STRIPE_COUNT, UINT64},
    {RBD_IMAGE_OPTION_JOURNAL_ORDER, UINT64},
    {RBD_IMAGE_OPTION_JOURNAL_SPLAY_WIDTH, UINT64},
    {RBD_IMAGE_OPTION_JOURNAL_POOL, STR},
    {RBD_IMAGE_OPTION_FEATURES_SET, UINT64},
    {RBD_IMAGE_OPTION_FEATURES_CLEAR, UINT64},
    {RBD_IMAGE_OPTION_DATA_POOL, STR},
  };

  std::string image_option_name(int optname) {
    switch (optname) {
    case RBD_IMAGE_OPTION_FORMAT:
      return "format";
    case RBD_IMAGE_OPTION_FEATURES:
      return "features";
    case RBD_IMAGE_OPTION_ORDER:
      return "order";
    case RBD_IMAGE_OPTION_STRIPE_UNIT:
      return "stripe_unit";
    case RBD_IMAGE_OPTION_STRIPE_COUNT:
      return "stripe_count";
    case RBD_IMAGE_OPTION_JOURNAL_ORDER:
      return "journal_order";
    case RBD_IMAGE_OPTION_JOURNAL_SPLAY_WIDTH:
      return "journal_splay_width";
    case RBD_IMAGE_OPTION_JOURNAL_POOL:
      return "journal_pool";
    case RBD_IMAGE_OPTION_FEATURES_SET:
      return "features_set";
    case RBD_IMAGE_OPTION_FEATURES_CLEAR:
      return "features_clear";
    case RBD_IMAGE_OPTION_DATA_POOL:
      return "data_pool";
    default:
      return "unknown (" + stringify(optname) + ")";
    }
  }

  std::ostream &operator<<(std::ostream &os, const ImageOptions &opts) {
    os << "[";

    const char *delimiter = "";
    for (auto &i : IMAGE_OPTIONS_TYPE_MAPPING) {
      if (i.second == STR) {
	std::string val;
	if (opts.get(i.first, &val) == 0) {
	  os << delimiter << image_option_name(i.first) << "=" << val;
	  delimiter = ", ";
	}
      } else if (i.second == UINT64) {
	uint64_t val;
	if (opts.get(i.first, &val) == 0) {
	  os << delimiter << image_option_name(i.first) << "=" << val;
	  delimiter = ", ";
	}
      }
    }

    os << "]";

    return os;
  }

  void image_options_create(rbd_image_options_t* opts)
  {
    image_options_ref* opts_ = new image_options_ref(new image_options_t());

    *opts = static_cast<rbd_image_options_t>(opts_);
  }

  void image_options_create_ref(rbd_image_options_t* opts,
				rbd_image_options_t orig)
  {
    image_options_ref* orig_ = static_cast<image_options_ref*>(orig);
    image_options_ref* opts_ = new image_options_ref(*orig_);

    *opts = static_cast<rbd_image_options_t>(opts_);
  }

  void image_options_copy(rbd_image_options_t* opts,
			  const ImageOptions &orig)
  {
    image_options_ref* opts_ = new image_options_ref(new image_options_t());

    *opts = static_cast<rbd_image_options_t>(opts_);

    std::string str_val;
    uint64_t uint64_val;
    for (auto &i : IMAGE_OPTIONS_TYPE_MAPPING) {
      switch (i.second) {
      case STR:
	if (orig.get(i.first, &str_val) == 0) {
	  image_options_set(*opts, i.first, str_val);
	}
	continue;
      case UINT64:
	if (orig.get(i.first, &uint64_val) == 0) {
	  image_options_set(*opts, i.first, uint64_val);
	}
	continue;
      }
    }
  }

  void image_options_destroy(rbd_image_options_t opts)
  {
    image_options_ref* opts_ = static_cast<image_options_ref*>(opts);

    delete opts_;
  }

  int image_options_set(rbd_image_options_t opts, int optname,
			const std::string& optval)
  {
    image_options_ref* opts_ = static_cast<image_options_ref*>(opts);

    std::map<int, image_option_type_t>::const_iterator i =
      IMAGE_OPTIONS_TYPE_MAPPING.find(optname);

    if (i == IMAGE_OPTIONS_TYPE_MAPPING.end() || i->second != STR) {
      return -EINVAL;
    }

    (*opts_->get())[optname] = optval;
    return 0;
  }

  int image_options_set(rbd_image_options_t opts, int optname, uint64_t optval)
  {
    image_options_ref* opts_ = static_cast<image_options_ref*>(opts);

    std::map<int, image_option_type_t>::const_iterator i =
      IMAGE_OPTIONS_TYPE_MAPPING.find(optname);

    if (i == IMAGE_OPTIONS_TYPE_MAPPING.end() || i->second != UINT64) {
      return -EINVAL;
    }

    (*opts_->get())[optname] = optval;
    return 0;
  }

  int image_options_get(rbd_image_options_t opts, int optname,
			std::string* optval)
  {
    image_options_ref* opts_ = static_cast<image_options_ref*>(opts);

    std::map<int, image_option_type_t>::const_iterator i =
      IMAGE_OPTIONS_TYPE_MAPPING.find(optname);

    if (i == IMAGE_OPTIONS_TYPE_MAPPING.end() || i->second != STR) {
      return -EINVAL;
    }

    image_options_t::const_iterator j = (*opts_)->find(optname);

    if (j == (*opts_)->end()) {
      return -ENOENT;
    }

    *optval = boost::get<std::string>(j->second);
    return 0;
  }

  int image_options_get(rbd_image_options_t opts, int optname, uint64_t* optval)
  {
    image_options_ref* opts_ = static_cast<image_options_ref*>(opts);

    std::map<int, image_option_type_t>::const_iterator i =
      IMAGE_OPTIONS_TYPE_MAPPING.find(optname);

    if (i == IMAGE_OPTIONS_TYPE_MAPPING.end() || i->second != UINT64) {
      return -EINVAL;
    }

    image_options_t::const_iterator j = (*opts_)->find(optname);

    if (j == (*opts_)->end()) {
      return -ENOENT;
    }

    *optval = boost::get<uint64_t>(j->second);
    return 0;
  }

  int image_options_is_set(rbd_image_options_t opts, int optname,
                           bool* is_set)
  {
    if (IMAGE_OPTIONS_TYPE_MAPPING.find(optname) ==
          IMAGE_OPTIONS_TYPE_MAPPING.end()) {
      return -EINVAL;
    }

    image_options_ref* opts_ = static_cast<image_options_ref*>(opts);
    *is_set = ((*opts_)->find(optname) != (*opts_)->end());
    return 0;
  }

  int image_options_unset(rbd_image_options_t opts, int optname)
  {
    image_options_ref* opts_ = static_cast<image_options_ref*>(opts);

    std::map<int, image_option_type_t>::const_iterator i =
      IMAGE_OPTIONS_TYPE_MAPPING.find(optname);

    if (i == IMAGE_OPTIONS_TYPE_MAPPING.end()) {
      assert((*opts_)->find(optname) == (*opts_)->end());
      return -EINVAL;
    }

    image_options_t::const_iterator j = (*opts_)->find(optname);

    if (j == (*opts_)->end()) {
      return -ENOENT;
    }

    (*opts_)->erase(j);
    return 0;
  }

  void image_options_clear(rbd_image_options_t opts)
  {
    image_options_ref* opts_ = static_cast<image_options_ref*>(opts);

    (*opts_)->clear();
  }

  bool image_options_is_empty(rbd_image_options_t opts)
  {
    image_options_ref* opts_ = static_cast<image_options_ref*>(opts);

    return (*opts_)->empty();
  }

  int list(IoCtx& io_ctx, vector<string>& names)
  {
    CephContext *cct = (CephContext *)io_ctx.cct();
    ldout(cct, 20) << "list " << &io_ctx << dendl;

    bufferlist bl;
    int r = io_ctx.read(RBD_DIRECTORY, bl, 0, 0);
    if (r < 0) {
      if (r == -ENOENT) {
        r = 0;
      }
      return r;
    }

    // old format images are in a tmap
    if (bl.length()) {
      bufferlist::iterator p = bl.begin();
      bufferlist header;
      map<string,bufferlist> m;
      ::decode(header, p);
      ::decode(m, p);
      for (map<string,bufferlist>::iterator q = m.begin(); q != m.end(); ++q) {
	names.push_back(q->first);
      }
    }

    map<string, string> images;
    r = api::Image<>::list_images(io_ctx, &images);
    if (r < 0) {
      lderr(cct) << "error listing v2 images: " << cpp_strerror(r) << dendl;
      return r;
    }
    for (const auto& img_pair : images) {
      names.push_back(img_pair.first);
    }

    return 0;
  }

  int flatten_children(ImageCtx *ictx, const char* snap_name,
                       ProgressContext& pctx)
  {
    CephContext *cct = ictx->cct;
    ldout(cct, 20) << "children flatten " << ictx->name << dendl;

    RWLock::RLocker l(ictx->snap_lock);
    snap_t snap_id = ictx->get_snap_id(cls::rbd::UserSnapshotNamespace(), snap_name);
    ParentSpec parent_spec(ictx->md_ctx.get_id(), ictx->id, snap_id);
    map< pair<int64_t, string>, set<string> > image_info;

    int r = api::Image<>::list_children(ictx, parent_spec, &image_info);
    if (r < 0) {
      return r;
    }

    size_t size = image_info.size();
    if (size == 0)
      return 0;

    size_t i = 0;
    Rados rados(ictx->md_ctx);
    for ( auto &info : image_info){
      string pool = info.first.second;
      IoCtx ioctx;
      r = rados.ioctx_create2(info.first.first, ioctx);
      if (r < 0) {
        lderr(cct) << "Error accessing child image pool " << pool
                   << dendl;
        return r;
      }

      for (auto &id_it : info.second) {
	ImageCtx *imctx = new ImageCtx("", id_it, NULL, ioctx, false);
	int r = imctx->state->open(false);
	if (r < 0) {
	  lderr(cct) << "error opening image: "
		     << cpp_strerror(r) << dendl;
	  return r;
	}

	librbd::NoOpProgressContext prog_ctx;
	r = imctx->operations->flatten(prog_ctx);
	if (r < 0) {
	  lderr(cct) << "error flattening image: " << pool << "/" << id_it
		     << cpp_strerror(r) << dendl;
          imctx->state->close();
	  return r;
	}

	if ((imctx->features & RBD_FEATURE_DEEP_FLATTEN) == 0 &&
	    !imctx->snaps.empty()) {
	  imctx->parent_lock.get_read();
	  ParentInfo parent_info = imctx->parent_md;
	  imctx->parent_lock.put_read();

	  r = cls_client::remove_child(&imctx->md_ctx, RBD_CHILDREN,
				       parent_info.spec, imctx->id);
	  if (r < 0 && r != -ENOENT) {
	    lderr(cct) << "error removing child from children list" << dendl;
	    imctx->state->close();
	    return r;
	  }
	}

	r = imctx->state->close();
        if (r < 0) {
          lderr(cct) << "failed to close image: " << cpp_strerror(r) << dendl;
          return r;
        }
      }
      pctx.update_progress(++i, size);
      assert(i <= size);
    }

    return 0;
  }

  int list_children(ImageCtx *ictx, set<pair<string, string> >& names)
  {
    CephContext *cct = ictx->cct;
    ldout(cct, 20) << "children list " << ictx->name << dendl;

    RWLock::RLocker l(ictx->snap_lock);
    ParentSpec parent_spec(ictx->md_ctx.get_id(), ictx->id, ictx->snap_id);
    map< pair<int64_t, string>, set<string> > image_info;

    int r = api::Image<>::list_children(ictx, parent_spec, &image_info);
    if (r < 0) {
      return r;
    }

    Rados rados(ictx->md_ctx);
    for ( auto &info : image_info){
      IoCtx ioctx;
      r = rados.ioctx_create2(info.first.first, ioctx);
      if (r < 0) {
        lderr(cct) << "Error accessing child image pool " << info.first.second
                   << dendl;
        return r;
      }

      for (auto &id_it : info.second) {
	string name;
	r = cls_client::dir_get_name(&ioctx, RBD_DIRECTORY, id_it, &name);
	if (r < 0) {
	  lderr(cct) << "Error looking up name for image id " << id_it
		     << " in pool " << info.first.second << dendl;
	  return r;
	}
	names.insert(make_pair(info.first.second, name));
      }
    }
    
    return 0;
  }

  int get_snap_namespace(ImageCtx *ictx,
			 const char *snap_name,
			 cls::rbd::SnapshotNamespace *snap_namespace) {
    ldout(ictx->cct, 20) << "get_snap_namespace " << ictx << " " << snap_name
			 << dendl;

    int r = ictx->state->refresh_if_required();
    if (r < 0)
      return r;
    RWLock::RLocker l(ictx->snap_lock);
    snap_t snap_id = ictx->get_snap_id(*snap_namespace, snap_name);
    if (snap_id == CEPH_NOSNAP)
      return -ENOENT;
    r = ictx->get_snap_namespace(snap_id, snap_namespace);
    return r;
  }

  int snap_is_protected(ImageCtx *ictx, const char *snap_name, bool *is_protected)
  {
    ldout(ictx->cct, 20) << "snap_is_protected " << ictx << " " << snap_name
			 << dendl;

    int r = ictx->state->refresh_if_required();
    if (r < 0)
      return r;

    RWLock::RLocker l(ictx->snap_lock);
    snap_t snap_id = ictx->get_snap_id(cls::rbd::UserSnapshotNamespace(), snap_name);
    if (snap_id == CEPH_NOSNAP)
      return -ENOENT;
    bool is_unprotected;
    r = ictx->is_snap_unprotected(snap_id, &is_unprotected);
    // consider both PROTECTED or UNPROTECTING to be 'protected',
    // since in either state they can't be deleted
    *is_protected = !is_unprotected;
    return r;
  }

  int create_v1(IoCtx& io_ctx, const char *imgname, uint64_t size, int order)
  {
    CephContext *cct = (CephContext *)io_ctx.cct();

    ldout(cct, 20) << __func__ << " "  << &io_ctx << " name = " << imgname
		   << " size = " << size << " order = " << order << dendl;
    int r = validate_pool(io_ctx, cct);
    if (r < 0) {
      return r;
    }

    ldout(cct, 2) << "adding rbd image to directory..." << dendl;
    r = tmap_set(io_ctx, imgname);
    if (r < 0) {
      lderr(cct) << "error adding image to directory: " << cpp_strerror(r)
		 << dendl;
      return r;
    }

    Rados rados(io_ctx);
    uint64_t bid = rados.get_instance_id();

    ldout(cct, 2) << "creating rbd image..." << dendl;
    struct rbd_obj_header_ondisk header;
    init_rbd_header(header, size, order, bid);

    bufferlist bl;
    bl.append((const char *)&header, sizeof(header));

    string header_oid = util::old_header_name(imgname);
    r = io_ctx.write(header_oid, bl, bl.length(), 0);
    if (r < 0) {
      lderr(cct) << "Error writing image header: " << cpp_strerror(r)
		 << dendl;
      int remove_r = tmap_rm(io_ctx, imgname);
      if (remove_r < 0) {
	lderr(cct) << "Could not remove image from directory after "
		   << "header creation failed: "
		   << cpp_strerror(remove_r) << dendl;
      }
      return r;
    }

    ldout(cct, 2) << "done." << dendl;
    return 0;
  }

  int create(librados::IoCtx& io_ctx, const char *imgname, uint64_t size,
	     int *order)
  {
    uint64_t order_ = *order;
    ImageOptions opts;

    int r = opts.set(RBD_IMAGE_OPTION_ORDER, order_);
    assert(r == 0);

    r = create(io_ctx, imgname, "", size, opts, "", "", false);

    int r1 = opts.get(RBD_IMAGE_OPTION_ORDER, &order_);
    assert(r1 == 0);
    *order = order_;

    return r;
  }

  int create(IoCtx& io_ctx, const char *imgname, uint64_t size,
	     bool old_format, uint64_t features, int *order,
	     uint64_t stripe_unit, uint64_t stripe_count)
  {
    if (!order)
      return -EINVAL;

    uint64_t order_ = *order;
    uint64_t format = old_format ? 1 : 2;
    ImageOptions opts;
    int r;

    r = opts.set(RBD_IMAGE_OPTION_FORMAT, format);
    assert(r == 0);
    r = opts.set(RBD_IMAGE_OPTION_FEATURES, features);
    assert(r == 0);
    r = opts.set(RBD_IMAGE_OPTION_ORDER, order_);
    assert(r == 0);
    r = opts.set(RBD_IMAGE_OPTION_STRIPE_UNIT, stripe_unit);
    assert(r == 0);
    r = opts.set(RBD_IMAGE_OPTION_STRIPE_COUNT, stripe_count);
    assert(r == 0);

    r = create(io_ctx, imgname, "", size, opts, "", "", false);

    int r1 = opts.get(RBD_IMAGE_OPTION_ORDER, &order_);
    assert(r1 == 0);
    *order = order_;

    return r;
  }

  int create(IoCtx& io_ctx, const std::string &image_name,
	     const std::string &image_id, uint64_t size,
	     ImageOptions& opts,
             const std::string &non_primary_global_image_id,
             const std::string &primary_mirror_uuid,
             bool skip_mirror_enable)
  {
    std::string id(image_id);
    if (id.empty()) {
      id = util::generate_image_id(io_ctx);
    }

    CephContext *cct = (CephContext *)io_ctx.cct();
    ldout(cct, 10) << __func__ << " name=" << image_name << ", "
		   << "id= " << id << ", "
		   << "size=" << size << ", opts=" << opts << dendl;

    uint64_t format;
    if (opts.get(RBD_IMAGE_OPTION_FORMAT, &format) != 0)
      format = cct->_conf->get_val<int64_t>("rbd_default_format");
    bool old_format = format == 1;

    // make sure it doesn't already exist, in either format
    int r = detect_format(io_ctx, image_name, NULL, NULL);
    if (r != -ENOENT) {
      if (r) {
	lderr(cct) << "Could not tell if " << image_name << " already exists"
		   << dendl;
	return r;
      }
      lderr(cct) << "rbd image " << image_name << " already exists" << dendl;
      return -EEXIST;
    }

    uint64_t order = 0;
    if (opts.get(RBD_IMAGE_OPTION_ORDER, &order) != 0 || order == 0) {
      order = cct->_conf->get_val<int64_t>("rbd_default_order");
    }
    r = image::CreateRequest<>::validate_order(cct, order);
    if (r < 0) {
      return r;
    }

    if (old_format) {
      r = create_v1(io_ctx, image_name.c_str(), size, order);
    } else {
      ThreadPool *thread_pool;
      ContextWQ *op_work_queue;
      ImageCtx::get_thread_pool_instance(cct, &thread_pool, &op_work_queue);

      C_SaferCond cond;
      image::CreateRequest<> *req = image::CreateRequest<>::create(
        io_ctx, image_name, id, size, opts, non_primary_global_image_id,
        primary_mirror_uuid, skip_mirror_enable, op_work_queue, &cond);
      req->send();

      r = cond.wait();
    }

    int r1 = opts.set(RBD_IMAGE_OPTION_ORDER, order);
    assert(r1 == 0);

    return r;
  }

  /*
   * Parent may be in different pool, hence different IoCtx
   */
  int clone(IoCtx& p_ioctx, const char *p_name, const char *p_snap_name,
	    IoCtx& c_ioctx, const char *c_name,
	    uint64_t features, int *c_order,
	    uint64_t stripe_unit, int stripe_count)
  {
    uint64_t order = *c_order;

    ImageOptions opts;
    opts.set(RBD_IMAGE_OPTION_FEATURES, features);
    opts.set(RBD_IMAGE_OPTION_ORDER, order);
    opts.set(RBD_IMAGE_OPTION_STRIPE_UNIT, stripe_unit);
    opts.set(RBD_IMAGE_OPTION_STRIPE_COUNT, stripe_count);

    int r = clone(p_ioctx, p_name, p_snap_name, c_ioctx, c_name, opts);
    opts.get(RBD_IMAGE_OPTION_ORDER, &order);
    *c_order = order;
    return r;
  }

  int clone(IoCtx& p_ioctx, const char *p_name, const char *p_snap_name,
	    IoCtx& c_ioctx, const char *c_name, ImageOptions& c_opts)
  {
    CephContext *cct = (CephContext *)p_ioctx.cct();
    if (p_snap_name == NULL) {
      lderr(cct) << "image to be cloned must be a snapshot" << dendl;
      return -EINVAL;
    }

    // make sure parent snapshot exists
    ImageCtx *p_imctx = new ImageCtx(p_name, "", p_snap_name, p_ioctx, true);
    int r = p_imctx->state->open(false);
    if (r < 0) {
      lderr(cct) << "error opening parent image: "
		 << cpp_strerror(r) << dendl;
      return r;
    }

    r = clone(p_imctx, c_ioctx, c_name, "", c_opts, "", "");

    int close_r = p_imctx->state->close();
    if (r == 0 && close_r < 0) {
      r = close_r;
    }

    if (r < 0) {
      return r;
    }
    return 0;
  }

  int clone(ImageCtx *p_imctx, IoCtx& c_ioctx, const std::string &c_name,
            const std::string &c_id, ImageOptions& c_opts,
            const std::string &non_primary_global_image_id,
            const std::string &primary_mirror_uuid)
  {
    std::string id(c_id);
    if (id.empty()) {
      id = util::generate_image_id(c_ioctx);
    }

    CephContext *cct = (CephContext *)c_ioctx.cct();
    ldout(cct, 10) << __func__ << " "
		   << "c_name=" << c_name << ", "
		   << "c_id= " << c_id << ", "
		   << "c_opts=" << c_opts << dendl;

    ThreadPool *thread_pool;
    ContextWQ *op_work_queue;
    ImageCtx::get_thread_pool_instance(cct, &thread_pool, &op_work_queue);

    C_SaferCond cond;
    auto *req = image::CloneRequest<>::create(
      p_imctx, c_ioctx, c_name, id, c_opts,
      non_primary_global_image_id, primary_mirror_uuid, op_work_queue, &cond);
    req->send();

    return cond.wait();
  }

  int rename(IoCtx& io_ctx, const char *srcname, const char *dstname)
  {
    CephContext *cct = (CephContext *)io_ctx.cct();
    ldout(cct, 20) << "rename " << &io_ctx << " " << srcname << " -> "
		   << dstname << dendl;

    ImageCtx *ictx = new ImageCtx(srcname, "", "", io_ctx, false);
    int r = ictx->state->open(false);
    if (r < 0) {
      lderr(cct) << "error opening source image: " << cpp_strerror(r) << dendl;
      return r;
    }
    BOOST_SCOPE_EXIT((ictx)) {
      ictx->state->close();
    } BOOST_SCOPE_EXIT_END

    return ictx->operations->rename(dstname);
  }

  int info(ImageCtx *ictx, image_info_t& info, size_t infosize)
  {
    ldout(ictx->cct, 20) << "info " << ictx << dendl;

    int r = ictx->state->refresh_if_required();
    if (r < 0)
      return r;

    image_info(ictx, info, infosize);
    return 0;
  }

  int get_old_format(ImageCtx *ictx, uint8_t *old)
  {
    int r = ictx->state->refresh_if_required();
    if (r < 0)
      return r;
    *old = ictx->old_format;
    return 0;
  }

  int get_size(ImageCtx *ictx, uint64_t *size)
  {
    int r = ictx->state->refresh_if_required();
    if (r < 0)
      return r;
    RWLock::RLocker l2(ictx->snap_lock);
    *size = ictx->get_image_size(ictx->snap_id);
    return 0;
  }

  int get_features(ImageCtx *ictx, uint64_t *features)
  {
    int r = ictx->state->refresh_if_required();
    if (r < 0)
      return r;
    RWLock::RLocker l(ictx->snap_lock);
    *features = ictx->features;
    return 0;
  }

  int get_overlap(ImageCtx *ictx, uint64_t *overlap)
  {
    int r = ictx->state->refresh_if_required();
    if (r < 0)
      return r;
    RWLock::RLocker l(ictx->snap_lock);
    RWLock::RLocker l2(ictx->parent_lock);
    return ictx->get_parent_overlap(ictx->snap_id, overlap);
  }

  int get_parent_info(ImageCtx *ictx, string *parent_pool_name,
                      string *parent_name, string *parent_id,
                      string *parent_snap_name)
  {
    int r = ictx->state->refresh_if_required();
    if (r < 0)
      return r;

    RWLock::RLocker l(ictx->snap_lock);
    RWLock::RLocker l2(ictx->parent_lock);
    if (ictx->parent == NULL) {
      return -ENOENT;
    }

    ParentSpec parent_spec;

    if (ictx->snap_id == CEPH_NOSNAP) {
      parent_spec = ictx->parent_md.spec;
    } else {
      r = ictx->get_parent_spec(ictx->snap_id, &parent_spec);
      if (r < 0) {
	lderr(ictx->cct) << "Can't find snapshot id = " << ictx->snap_id
                         << dendl;
	return r;
      }
      if (parent_spec.pool_id == -1)
	return -ENOENT;
    }
    if (parent_pool_name) {
      Rados rados(ictx->md_ctx);
      r = rados.pool_reverse_lookup(parent_spec.pool_id,
				    parent_pool_name);
      if (r < 0) {
	lderr(ictx->cct) << "error looking up pool name: " << cpp_strerror(r)
			 << dendl;
	return r;
      }
    }

    if (parent_snap_name) {
      RWLock::RLocker l(ictx->parent->snap_lock);
      r = ictx->parent->get_snap_name(parent_spec.snap_id,
				      parent_snap_name);
      if (r < 0) {
	lderr(ictx->cct) << "error finding parent snap name: "
			 << cpp_strerror(r) << dendl;
	return r;
      }
    }

    if (parent_name) {
      RWLock::RLocker snap_locker(ictx->parent->snap_lock);
      *parent_name = ictx->parent->name;
    }
    if (parent_id) {
      *parent_id = ictx->parent->id;
    }

    return 0;
  }

  int get_flags(ImageCtx *ictx, uint64_t *flags)
  {
    int r = ictx->state->refresh_if_required();
    if (r < 0) {
      return r;
    }

    RWLock::RLocker l2(ictx->snap_lock);
    return ictx->get_flags(ictx->snap_id, flags);
  }

  int set_image_notification(ImageCtx *ictx, int fd, int type)
  {
    CephContext *cct = ictx->cct;
    ldout(cct, 20) << __func__ << " " << ictx << " fd " << fd << " type" << type << dendl;

    int r = ictx->state->refresh_if_required();
    if (r < 0) {
      return r;
    }

    if (ictx->event_socket.is_valid())
      return -EINVAL;
    return ictx->event_socket.init(fd, type);
  }

  int is_exclusive_lock_owner(ImageCtx *ictx, bool *is_owner)
  {
    *is_owner = false;

    RWLock::RLocker owner_locker(ictx->owner_lock);
    if (ictx->exclusive_lock == nullptr ||
        !ictx->exclusive_lock->is_lock_owner()) {
      return 0;
    }

    // might have been blacklisted by peer -- ensure we still own
    // the lock by pinging the OSD
    int r = ictx->exclusive_lock->assert_header_locked();
    if (r == -EBUSY || r == -ENOENT) {
      return 0;
    } else if (r < 0) {
      return r;
    }

    *is_owner = true;
    return 0;
  }

  int lock_acquire(ImageCtx *ictx, rbd_lock_mode_t lock_mode)
  {
    CephContext *cct = ictx->cct;
    ldout(cct, 20) << __func__ << ": ictx=" << ictx << ", "
                   << "lock_mode=" << lock_mode << dendl;

    if (lock_mode != RBD_LOCK_MODE_EXCLUSIVE) {
      return -EOPNOTSUPP;
    }

    C_SaferCond lock_ctx;
    {
      RWLock::WLocker l(ictx->owner_lock);

      if (ictx->exclusive_lock == nullptr) {
	lderr(cct) << "exclusive-lock feature is not enabled" << dendl;
	return -EINVAL;
      }

      if (ictx->get_exclusive_lock_policy()->may_auto_request_lock()) {
	ictx->set_exclusive_lock_policy(
	  new exclusive_lock::StandardPolicy(ictx));
      }

      if (ictx->exclusive_lock->is_lock_owner()) {
	return 0;
      }

      ictx->exclusive_lock->acquire_lock(&lock_ctx);
    }

    int r = lock_ctx.wait();
    if (r < 0) {
      lderr(cct) << "failed to request exclusive lock: " << cpp_strerror(r)
		 << dendl;
      return r;
    }

    RWLock::RLocker l(ictx->owner_lock);

    if (ictx->exclusive_lock == nullptr ||
	!ictx->exclusive_lock->is_lock_owner()) {
      lderr(cct) << "failed to acquire exclusive lock" << dendl;
      return -EROFS;
    }

    return 0;
  }

  int lock_release(ImageCtx *ictx)
  {
    CephContext *cct = ictx->cct;
    ldout(cct, 20) << __func__ << ": ictx=" << ictx << dendl;

    C_SaferCond lock_ctx;
    {
      RWLock::WLocker l(ictx->owner_lock);

      if (ictx->exclusive_lock == nullptr ||
	  !ictx->exclusive_lock->is_lock_owner()) {
	lderr(cct) << "not exclusive lock owner" << dendl;
	return -EINVAL;
      }

      ictx->exclusive_lock->release_lock(&lock_ctx);
    }

    int r = lock_ctx.wait();
    if (r < 0) {
      lderr(cct) << "failed to release exclusive lock: " << cpp_strerror(r)
		 << dendl;
      return r;
    }
    return 0;
  }

  int lock_get_owners(ImageCtx *ictx, rbd_lock_mode_t *lock_mode,
                      std::list<std::string> *lock_owners)
  {
    CephContext *cct = ictx->cct;
    ldout(cct, 20) << __func__ << ": ictx=" << ictx << dendl;

    if (!ictx->test_features(RBD_FEATURE_EXCLUSIVE_LOCK)) {
      lderr(cct) << "exclusive-lock feature is not enabled" << dendl;
      return -EINVAL;
    }

    managed_lock::Locker locker;
    C_SaferCond get_owner_ctx;
    ExclusiveLock<>(*ictx).get_locker(&locker, &get_owner_ctx);
    int r = get_owner_ctx.wait();
    if (r == -ENOENT) {
      return r;
    } else if (r < 0) {
      lderr(cct) << "failed to determine current lock owner: "
                 << cpp_strerror(r) << dendl;
      return r;
    }

    *lock_mode = RBD_LOCK_MODE_EXCLUSIVE;
    lock_owners->clear();
    lock_owners->emplace_back(locker.address);
    return 0;
  }

  int lock_break(ImageCtx *ictx, rbd_lock_mode_t lock_mode,
                 const std::string &lock_owner)
  {
    CephContext *cct = ictx->cct;
    ldout(cct, 20) << __func__ << ": ictx=" << ictx << ", "
                   << "lock_mode=" << lock_mode << ", "
                   << "lock_owner=" << lock_owner << dendl;

    if (lock_mode != RBD_LOCK_MODE_EXCLUSIVE) {
      return -EOPNOTSUPP;
    }

    if (ictx->read_only) {
      return -EROFS;
    }

    managed_lock::Locker locker;
    C_SaferCond get_owner_ctx;
    {
      RWLock::RLocker l(ictx->owner_lock);

      if (ictx->exclusive_lock == nullptr) {
        lderr(cct) << "exclusive-lock feature is not enabled" << dendl;
        return -EINVAL;
      }

      ictx->exclusive_lock->get_locker(&locker, &get_owner_ctx);
    }
    int r = get_owner_ctx.wait();
    if (r == -ENOENT) {
      return r;
    } else if (r < 0) {
      lderr(cct) << "failed to determine current lock owner: "
                 << cpp_strerror(r) << dendl;
      return r;
    }

    if (locker.address != lock_owner) {
      return -EBUSY;
    }

    C_SaferCond break_ctx;
    {
      RWLock::RLocker l(ictx->owner_lock);

      if (ictx->exclusive_lock == nullptr) {
        lderr(cct) << "exclusive-lock feature is not enabled" << dendl;
        return -EINVAL;
      }

      ictx->exclusive_lock->break_lock(locker, true, &break_ctx);
    }
    r = break_ctx.wait();
    if (r == -ENOENT) {
      return r;
    } else if (r < 0) {
      lderr(cct) << "failed to break lock: " << cpp_strerror(r) << dendl;
      return r;
    }
    return 0;
  }

  int remove(IoCtx& io_ctx, const std::string &image_name,
             const std::string &image_id, ProgressContext& prog_ctx,
             bool force, bool from_trash_remove)
  {
    CephContext *cct((CephContext *)io_ctx.cct());
    ldout(cct, 20) << "remove " << &io_ctx << " "
                   << (image_id.empty() ? image_name : image_id) << dendl;

    ThreadPool *thread_pool;
    ContextWQ *op_work_queue;
    ImageCtx::get_thread_pool_instance(cct, &thread_pool, &op_work_queue);

    C_SaferCond cond;
    auto req = librbd::image::RemoveRequest<>::create(
      io_ctx, image_name, image_id, force, from_trash_remove, prog_ctx,
      op_work_queue, &cond);
    req->send();

    return cond.wait();
  }

  int trash_move(librados::IoCtx &io_ctx, rbd_trash_image_source_t source,
                 const std::string &image_name, uint64_t delay) {
    CephContext *cct((CephContext *)io_ctx.cct());
    ldout(cct, 20) << "trash_move " << &io_ctx << " " << image_name
                   << dendl;

    std::string image_id;
    ImageCtx *ictx = new ImageCtx(image_name, "", nullptr, io_ctx, false);
    int r = ictx->state->open(true);
    if (r < 0) {
      ictx = nullptr;

      if (r != -ENOENT) {
        ldout(cct, 2) << "error opening image: " << cpp_strerror(-r) << dendl;
        return r;
      }

      // try to get image id from the directory
      r = cls_client::dir_get_id(&io_ctx, RBD_DIRECTORY, image_name, &image_id);
      if (r < 0) {
        if (r != -ENOENT) {
          ldout(cct, 2) << "error reading image id from dirctory: "
                        << cpp_strerror(-r) << dendl;
        }
        return r;
      }
    } else {
      if (ictx->old_format) {
        ictx->state->close();
        return -EOPNOTSUPP;
      }

      image_id = ictx->id;
      ictx->owner_lock.get_read();
      if (ictx->exclusive_lock != nullptr) {
        r = ictx->operations->prepare_image_update();
        if (r < 0 || (ictx->exclusive_lock != nullptr &&
                      !ictx->exclusive_lock->is_lock_owner())) {
	  lderr(cct) << "cannot obtain exclusive lock - not removing" << dendl;
	  ictx->owner_lock.put_read();
	  ictx->state->close();
          return -EBUSY;
        }
      }
    }

    BOOST_SCOPE_EXIT_ALL(ictx, cct) {
      if (ictx == nullptr)
        return;

      bool is_locked = ictx->exclusive_lock != nullptr &&
                       ictx->exclusive_lock->is_lock_owner();
      if (is_locked) {
        C_SaferCond ctx;
        auto exclusive_lock = ictx->exclusive_lock;
        exclusive_lock->shut_down(&ctx);
        ictx->owner_lock.put_read();
        int r = ctx.wait();
        if (r < 0) {
          lderr(cct) << "error shutting down exclusive lock" << dendl;
        }
        delete exclusive_lock;
      } else {
        ictx->owner_lock.put_read();
      }
      ictx->state->close();
    };

    ldout(cct, 2) << "adding image entry to rbd_trash" << dendl;
    utime_t ts = ceph_clock_now();
    utime_t deferment_end_time = ts;
    deferment_end_time += (double)delay;
    cls::rbd::TrashImageSource trash_source =
        static_cast<cls::rbd::TrashImageSource>(source);
    cls::rbd::TrashImageSpec trash_spec(trash_source, image_name, ts,
                                        deferment_end_time);
    r = cls_client::trash_add(&io_ctx, image_id, trash_spec);
    if (r < 0 && r != -EEXIST) {
      lderr(cct) << "error adding image " << image_name << " to rbd_trash"
                 << dendl;
      return r;
    } else if (r == -EEXIST) {
      ldout(cct, 10) << "found previous unfinished deferred remove for image:"
                     << image_id << dendl;
      // continue with removing image from directory
    }

    ldout(cct, 2) << "removing id object..." << dendl;
    r = io_ctx.remove(util::id_obj_name(image_name));
    if (r < 0 && r != -ENOENT) {
      lderr(cct) << "error removing id object: " << cpp_strerror(r)
                 << dendl;
      return r;
    }

    ldout(cct, 2) << "removing rbd image from v2 directory..." << dendl;
    r = cls_client::dir_remove_image(&io_ctx, RBD_DIRECTORY, image_name,
                                     image_id);
    if (r < 0) {
      if (r != -ENOENT) {
        lderr(cct) << "error removing image from v2 directory: "
                   << cpp_strerror(-r) << dendl;
      }
      return r;
    }

    return 0;
  }

  int trash_get(IoCtx &io_ctx, const std::string &id,
                trash_image_info_t *info) {
    CephContext *cct((CephContext *)io_ctx.cct());
    ldout(cct, 20) << __func__ << " " << &io_ctx << dendl;

    cls::rbd::TrashImageSpec spec;
    int r = cls_client::trash_get(&io_ctx, id, &spec);
    if (r == -ENOENT) {
      return r;
    } else if (r < 0) {
      lderr(cct) << "error retrieving trash entry: " << cpp_strerror(r)
                 << dendl;
      return r;
    }

    rbd_trash_image_source_t source = static_cast<rbd_trash_image_source_t>(
      spec.source);
    *info = trash_image_info_t{id, spec.name, source, spec.deletion_time.sec(),
                               spec.deferment_end_time.sec()};
    return 0;
  }

  int trash_list(IoCtx &io_ctx, vector<trash_image_info_t> &entries) {
    CephContext *cct((CephContext *)io_ctx.cct());
    ldout(cct, 20) << "trash_list " << &io_ctx << dendl;

    bool more_entries;
    uint32_t max_read = 1024;
    std::string last_read = "";
    do {
      map<string, cls::rbd::TrashImageSpec> trash_entries;
      int r = cls_client::trash_list(&io_ctx, last_read, max_read,
                                     &trash_entries);
      if (r < 0 && r != -ENOENT) {
        lderr(cct) << "error listing rbd trash entries: " << cpp_strerror(r)
                   << dendl;
        return r;
      } else if (r == -ENOENT) {
        break;
      }

      if (trash_entries.empty()) {
        break;
      }

      for (const auto &entry : trash_entries) {
        rbd_trash_image_source_t source =
            static_cast<rbd_trash_image_source_t>(entry.second.source);
        entries.push_back({entry.first, entry.second.name, source,
                           entry.second.deletion_time.sec(),
                           entry.second.deferment_end_time.sec()});
      }
      last_read = trash_entries.rbegin()->first;
      more_entries = (trash_entries.size() >= max_read);
    } while (more_entries);

    return 0;
  }

  int trash_remove(IoCtx &io_ctx, const std::string &image_id, bool force,
                   ProgressContext& prog_ctx) {
    CephContext *cct((CephContext *)io_ctx.cct());
    ldout(cct, 20) << "trash_remove " << &io_ctx << " " << image_id
                   << " " << force << dendl;

    cls::rbd::TrashImageSpec trash_spec;
    int r = cls_client::trash_get(&io_ctx, image_id, &trash_spec);
    if (r < 0) {
      lderr(cct) << "error getting image id " << image_id
                 << " info from trash: " << cpp_strerror(r) << dendl;
      return r;
    }

    utime_t now = ceph_clock_now();
    if (now < trash_spec.deferment_end_time && !force) {
      lderr(cct) << "error: deferment time has not expired." << dendl;
      return -EPERM;
    }

    r = remove(io_ctx, "", image_id, prog_ctx, false, true);
    if (r < 0) {
      lderr(cct) << "error removing image " << image_id
                 << ", which is pending deletion" << dendl;
      return r;
    }
    r = cls_client::trash_remove(&io_ctx, image_id);
    if (r < 0 && r != -ENOENT) {
      lderr(cct) << "error removing image " << image_id
                 << " from rbd_trash object" << dendl;
      return r;
    }
    return 0;
  }

  int trash_restore(librados::IoCtx &io_ctx, const std::string &image_id,
                    const std::string &image_new_name) {
    CephContext *cct((CephContext *)io_ctx.cct());
    ldout(cct, 20) << "trash_restore " << &io_ctx << " " << image_id << " "
                   << image_new_name << dendl;

    cls::rbd::TrashImageSpec trash_spec;
    int r = cls_client::trash_get(&io_ctx, image_id, &trash_spec);
    if (r < 0) {
      lderr(cct) << "error getting image id " << image_id
                 << " info from trash: " << cpp_strerror(r) << dendl;
      return r;
    }

    std::string image_name = image_new_name;
    if (image_name.empty()) {
      // if user didn't specify a new name, let's try using the old name
      image_name = trash_spec.name;
      ldout(cct, 20) << "restoring image id " << image_id << " with name "
                     << image_name << dendl;
    }

    // check if no image exists with the same name
    bool create_id_obj = true;
    std::string existing_id;
    r = cls_client::get_id(&io_ctx, util::id_obj_name(image_name), &existing_id);
    if (r < 0 && r != -ENOENT) {
      lderr(cct) << "error checking if image " << image_name << " exists: "
                 << cpp_strerror(r) << dendl;
      return r;
    } else if (r != -ENOENT){
      // checking if we are recovering from an incomplete restore
      if (existing_id != image_id) {
        ldout(cct, 2) << "an image with the same name already exists" << dendl;
        return -EEXIST;
      }
      create_id_obj = false;
    }

    if (create_id_obj) {
      ldout(cct, 2) << "adding id object" << dendl;
      librados::ObjectWriteOperation op;
      op.create(true);
      cls_client::set_id(&op, image_id);
      r = io_ctx.operate(util::id_obj_name(image_name), &op);
      if (r < 0) {
        lderr(cct) << "error adding id object for image " << image_name
                   << ": " << cpp_strerror(r) << dendl;
        return r;
      }
    }

    ldout(cct, 2) << "adding rbd image from v2 directory..." << dendl;
    r = cls_client::dir_add_image(&io_ctx, RBD_DIRECTORY, image_name,
                                  image_id);
    if (r < 0 && r != -EEXIST) {
      lderr(cct) << "error adding image to v2 directory: "
                 << cpp_strerror(r) << dendl;
      return r;
    }

    ldout(cct, 2) << "removing image from trash..." << dendl;
    r = cls_client::trash_remove(&io_ctx, image_id);
    if (r < 0 && r != -ENOENT) {
      lderr(cct) << "error removing image id " << image_id << " from trash: "
                 << cpp_strerror(r) << dendl;
      return r;
    }

    return 0;
  }

  int snap_list(ImageCtx *ictx, vector<snap_info_t>& snaps)
  {
    ldout(ictx->cct, 20) << "snap_list " << ictx << dendl;

    int r = ictx->state->refresh_if_required();
    if (r < 0)
      return r;

    RWLock::RLocker l(ictx->snap_lock);
    for (map<snap_t, SnapInfo>::iterator it = ictx->snap_info.begin();
	 it != ictx->snap_info.end(); ++it) {
      snap_info_t info;
      info.name = it->second.name;
      info.id = it->first;
      info.size = it->second.size;
      snaps.push_back(info);
    }

    return 0;
  }

  int snap_exists(ImageCtx *ictx, const cls::rbd::SnapshotNamespace& snap_namespace,
		  const char *snap_name, bool *exists)
  {
    ldout(ictx->cct, 20) << "snap_exists " << ictx << " " << snap_name << dendl;

    int r = ictx->state->refresh_if_required();
    if (r < 0)
      return r;

    RWLock::RLocker l(ictx->snap_lock);
    *exists = ictx->get_snap_id(snap_namespace, snap_name) != CEPH_NOSNAP;
    return 0;
  }

  int snap_remove(ImageCtx *ictx, const char *snap_name, uint32_t flags,
		  ProgressContext& pctx)
  {
    ldout(ictx->cct, 20) << "snap_remove " << ictx << " " << snap_name << " flags: " << flags << dendl;

    int r = 0;

    r = ictx->state->refresh_if_required();
    if (r < 0)
      return r;

    if (flags & RBD_SNAP_REMOVE_FLATTEN) {
	r = flatten_children(ictx, snap_name, pctx);
	if (r < 0) {
	  return r;
	}
    }

    bool is_protected;
    r = snap_is_protected(ictx, snap_name, &is_protected);
    if (r < 0) {
      return r;
    }

    if (is_protected && flags & RBD_SNAP_REMOVE_UNPROTECT) {
      r = ictx->operations->snap_unprotect(cls::rbd::UserSnapshotNamespace(), snap_name);
      if (r < 0) {
	lderr(ictx->cct) << "failed to unprotect snapshot: " << snap_name << dendl;
	return r;
      }

      r = snap_is_protected(ictx, snap_name, &is_protected);
      if (r < 0) {
	return r;
      }
      if (is_protected) {
	lderr(ictx->cct) << "snapshot is still protected after unprotection" << dendl;
	ceph_abort();
      }
    }

    C_SaferCond ctx;
    ictx->operations->snap_remove(cls::rbd::UserSnapshotNamespace(), snap_name, &ctx);

    r = ctx.wait();
    return r;
  }

  int snap_get_timestamp(ImageCtx *ictx, uint64_t snap_id, struct timespec *timestamp)
  {
    std::map<librados::snap_t, SnapInfo>::iterator snap_it = ictx->snap_info.find(snap_id);
    assert(snap_it != ictx->snap_info.end());
    utime_t time = snap_it->second.timestamp;
    time.to_timespec(timestamp);
    return 0;
  }

  int snap_get_limit(ImageCtx *ictx, uint64_t *limit)
  {
    int r = cls_client::snapshot_get_limit(&ictx->md_ctx, ictx->header_oid,
                                           limit);
    if (r == -EOPNOTSUPP) {
      *limit = UINT64_MAX;
      r = 0;
    }
    return r;
  }

  int snap_set_limit(ImageCtx *ictx, uint64_t limit)
  {
    return ictx->operations->snap_set_limit(limit);
  }

  struct CopyProgressCtx {
    explicit CopyProgressCtx(ProgressContext &p)
      : destictx(NULL), src_size(0), prog_ctx(p)
    { }

    ImageCtx *destictx;
    uint64_t src_size;
    ProgressContext &prog_ctx;
  };

  int copy(ImageCtx *src, IoCtx& dest_md_ctx, const char *destname,
	   ImageOptions& opts, ProgressContext &prog_ctx, size_t sparse_size)
  {
    CephContext *cct = (CephContext *)dest_md_ctx.cct();
    ldout(cct, 20) << "copy " << src->name
		   << (src->snap_name.length() ? "@" + src->snap_name : "")
		   << " -> " << destname << " opts = " << opts << dendl;

    src->snap_lock.get_read();
    uint64_t features = src->features;
    uint64_t src_size = src->get_image_size(src->snap_id);
    src->snap_lock.put_read();
    uint64_t format = src->old_format ? 1 : 2;
    if (opts.get(RBD_IMAGE_OPTION_FORMAT, &format) != 0) {
      opts.set(RBD_IMAGE_OPTION_FORMAT, format);
    }
    uint64_t stripe_unit = src->stripe_unit;
    if (opts.get(RBD_IMAGE_OPTION_STRIPE_UNIT, &stripe_unit) != 0) {
      opts.set(RBD_IMAGE_OPTION_STRIPE_UNIT, stripe_unit);
    }
    uint64_t stripe_count = src->stripe_count;
    if (opts.get(RBD_IMAGE_OPTION_STRIPE_COUNT, &stripe_count) != 0) {
      opts.set(RBD_IMAGE_OPTION_STRIPE_COUNT, stripe_count);
    }
    uint64_t order = src->order;
    if (opts.get(RBD_IMAGE_OPTION_ORDER, &order) != 0) {
      opts.set(RBD_IMAGE_OPTION_ORDER, order);
    }
    if (opts.get(RBD_IMAGE_OPTION_FEATURES, &features) != 0) {
      opts.set(RBD_IMAGE_OPTION_FEATURES, features);
    }
    if (features & ~RBD_FEATURES_ALL) {
      lderr(cct) << "librbd does not support requested features" << dendl;
      return -ENOSYS;
    }

    int r = create(dest_md_ctx, destname, "", src_size, opts, "", "", false);
    if (r < 0) {
      lderr(cct) << "header creation failed" << dendl;
      return r;
    }
    opts.set(RBD_IMAGE_OPTION_ORDER, static_cast<uint64_t>(order));

    ImageCtx *dest = new librbd::ImageCtx(destname, "", NULL,
					  dest_md_ctx, false);
    r = dest->state->open(false);
    if (r < 0) {
      lderr(cct) << "failed to read newly created header" << dendl;
      return r;
    }

    r = copy(src, dest, prog_ctx, sparse_size);

    int close_r = dest->state->close();
    if (r == 0 && close_r < 0) {
      r = close_r;
    }
    return r;
  }

  class C_CopyWrite : public Context {
  public:
    C_CopyWrite(bufferlist *bl, Context* ctx)
      : m_bl(bl), m_ctx(ctx) {}
    void finish(int r) override {
      delete m_bl;
      m_ctx->complete(r);
    }
  private:
    bufferlist *m_bl;
    Context *m_ctx;
  };

  class C_CopyRead : public Context {
  public:
    C_CopyRead(SimpleThrottle *throttle, ImageCtx *dest, uint64_t offset,
	       bufferlist *bl, size_t sparse_size)
      : m_throttle(throttle), m_dest(dest), m_offset(offset), m_bl(bl),
      m_sparse_size(sparse_size) {
      m_throttle->start_op();
    }
    void finish(int r) override {
      if (r < 0) {
	lderr(m_dest->cct) << "error reading from source image at offset "
			   << m_offset << ": " << cpp_strerror(r) << dendl;
	delete m_bl;
	m_throttle->end_op(r);
	return;
      }
      assert(m_bl->length() == (size_t)r);

      if (m_bl->is_zero()) {
	delete m_bl;
	m_throttle->end_op(r);
	return;
      }

      if (!m_sparse_size) {
	m_sparse_size = (1 << m_dest->order);
      }

      auto *throttle = m_throttle;
      auto *end_op_ctx = new FunctionContext([throttle](int r) {
	throttle->end_op(r);
      });
      auto gather_ctx = new C_Gather(m_dest->cct, end_op_ctx);

      bufferptr m_ptr(m_bl->length());
      m_bl->rebuild(m_ptr);
      size_t write_offset = 0;
      size_t write_length = 0;
      size_t offset = 0;
      size_t length = m_bl->length();
      while (offset < length) {
	if (util::calc_sparse_extent(m_ptr,
				     m_sparse_size,
				     length,
				     &write_offset,
				     &write_length,
				     &offset)) {
	  bufferptr write_ptr(m_ptr, write_offset, write_length);
	  bufferlist *write_bl = new bufferlist();
	  write_bl->push_back(write_ptr);
	  Context *ctx = new C_CopyWrite(write_bl, gather_ctx->new_sub());
	  auto comp = io::AioCompletion::create(ctx);

	  // coordinate through AIO WQ to ensure lock is acquired if needed
	  m_dest->io_work_queue->aio_write(comp, m_offset + write_offset,
					   write_length,
					   std::move(*write_bl),
					   LIBRADOS_OP_FLAG_FADVISE_DONTNEED,
					   std::move(read_trace));
	  write_offset = offset;
	  write_length = 0;
	}
      }
      delete m_bl;
      assert(gather_ctx->get_sub_created_count() > 0);
      gather_ctx->activate();
    }

    ZTracer::Trace read_trace;

  private:
    SimpleThrottle *m_throttle;
    ImageCtx *m_dest;
    uint64_t m_offset;
    bufferlist *m_bl;
    size_t m_sparse_size;
  };

  int copy(ImageCtx *src, ImageCtx *dest, ProgressContext &prog_ctx, size_t sparse_size)
  {
    src->snap_lock.get_read();
    uint64_t src_size = src->get_image_size(src->snap_id);
    src->snap_lock.put_read();

    dest->snap_lock.get_read();
    uint64_t dest_size = dest->get_image_size(dest->snap_id);
    dest->snap_lock.put_read();

    CephContext *cct = src->cct;
    if (dest_size < src_size) {
      lderr(cct) << " src size " << src_size << " > dest size "
		 << dest_size << dendl;
      return -EINVAL;
    }
    int r;
    map<string, bufferlist> pairs;

    r = cls_client::metadata_list(&src->md_ctx, src->header_oid, "", 0, &pairs);
    if (r < 0 && r != -EOPNOTSUPP && r != -EIO) {
      lderr(cct) << "couldn't list metadata: " << cpp_strerror(r) << dendl;
      return r;
    } else if (r == 0 && !pairs.empty()) {
      r = cls_client::metadata_set(&dest->md_ctx, dest->header_oid, pairs);
      if (r < 0) {
        lderr(cct) << "couldn't set metadata: " << cpp_strerror(r) << dendl;
        return r;
      }
    }

    ZTracer::Trace trace;
    if (src->blkin_trace_all) {
      trace.init("copy", &src->trace_endpoint);
    }

    RWLock::RLocker owner_lock(src->owner_lock);
    SimpleThrottle throttle(src->concurrent_management_ops, false);
    uint64_t period = src->get_stripe_period();
    unsigned fadvise_flags = LIBRADOS_OP_FLAG_FADVISE_SEQUENTIAL |
			     LIBRADOS_OP_FLAG_FADVISE_NOCACHE;
    for (uint64_t offset = 0; offset < src_size; offset += period) {
      if (throttle.pending_error()) {
        return throttle.wait_for_ret();
      }

      uint64_t len = min(period, src_size - offset);
      bufferlist *bl = new bufferlist();
      auto ctx = new C_CopyRead(&throttle, dest, offset, bl, sparse_size);
      auto comp = io::AioCompletion::create_and_start<Context>(
	ctx, src, io::AIO_TYPE_READ);

      io::ImageReadRequest<> req(*src, comp, {{offset, len}},
				 io::ReadResult{bl}, fadvise_flags,
				 std::move(trace));
      ctx->read_trace = req.get_trace();

      req.send();
      prog_ctx.update_progress(offset, src_size);
    }

    r = throttle.wait_for_ret();
    if (r >= 0)
      prog_ctx.update_progress(src_size, src_size);
    return r;
  }

  int snap_set(ImageCtx *ictx, const cls::rbd::SnapshotNamespace &snap_namespace,
	       const char *snap_name)
  {
    ldout(ictx->cct, 20) << "snap_set " << ictx << " snap = "
			 << (snap_name ? snap_name : "NULL") << dendl;

    // ignore return value, since we may be set to a non-existent
    // snapshot and the user is trying to fix that
    ictx->state->refresh_if_required();

    C_SaferCond ctx;
    std::string name(snap_name == nullptr ? "" : snap_name);
    ictx->state->snap_set(snap_namespace, name, &ctx);

    int r = ctx.wait();
    if (r < 0) {
      if (r != -ENOENT) {
        lderr(ictx->cct) << "failed to " << (name.empty() ? "un" : "") << "set "
                         << "snapshot: " << cpp_strerror(r) << dendl;
      }
      return r;
    }

    return 0;
  }

  int list_lockers(ImageCtx *ictx,
		   std::list<locker_t> *lockers,
		   bool *exclusive,
		   string *tag)
  {
    ldout(ictx->cct, 20) << "list_locks on image " << ictx << dendl;

    int r = ictx->state->refresh_if_required();
    if (r < 0)
      return r;

    RWLock::RLocker locker(ictx->md_lock);
    if (exclusive)
      *exclusive = ictx->exclusive_locked;
    if (tag)
      *tag = ictx->lock_tag;
    if (lockers) {
      lockers->clear();
      map<rados::cls::lock::locker_id_t,
	  rados::cls::lock::locker_info_t>::const_iterator it;
      for (it = ictx->lockers.begin(); it != ictx->lockers.end(); ++it) {
	locker_t locker;
	locker.client = stringify(it->first.locker);
	locker.cookie = it->first.cookie;
	locker.address = stringify(it->second.addr);
	lockers->push_back(locker);
      }
    }

    return 0;
  }

  int lock(ImageCtx *ictx, bool exclusive, const string& cookie,
	   const string& tag)
  {
    ldout(ictx->cct, 20) << "lock image " << ictx << " exclusive=" << exclusive
			 << " cookie='" << cookie << "' tag='" << tag << "'"
			 << dendl;

    int r = ictx->state->refresh_if_required();
    if (r < 0)
      return r;

    /**
     * If we wanted we could do something more intelligent, like local
     * checks that we think we will succeed. But for now, let's not
     * duplicate that code.
     */
    {
      RWLock::RLocker locker(ictx->md_lock);
      r = rados::cls::lock::lock(&ictx->md_ctx, ictx->header_oid, RBD_LOCK_NAME,
			         exclusive ? LOCK_EXCLUSIVE : LOCK_SHARED,
			         cookie, tag, "", utime_t(), 0);
      if (r < 0) {
        return r;
      }
    }

    ictx->notify_update();
    return 0;
  }

  int unlock(ImageCtx *ictx, const string& cookie)
  {
    ldout(ictx->cct, 20) << "unlock image " << ictx
			 << " cookie='" << cookie << "'" << dendl;

    int r = ictx->state->refresh_if_required();
    if (r < 0)
      return r;

    {
      RWLock::RLocker locker(ictx->md_lock);
      r = rados::cls::lock::unlock(&ictx->md_ctx, ictx->header_oid,
				   RBD_LOCK_NAME, cookie);
      if (r < 0) {
        return r;
      }
    }

    ictx->notify_update();
    return 0;
  }

  int break_lock(ImageCtx *ictx, const string& client,
		 const string& cookie)
  {
    ldout(ictx->cct, 20) << "break_lock image " << ictx << " client='" << client
			 << "' cookie='" << cookie << "'" << dendl;

    int r = ictx->state->refresh_if_required();
    if (r < 0)
      return r;

    entity_name_t lock_client;
    if (!lock_client.parse(client)) {
      lderr(ictx->cct) << "Unable to parse client '" << client
		       << "'" << dendl;
      return -EINVAL;
    }

    if (ictx->blacklist_on_break_lock) {
      typedef std::map<rados::cls::lock::locker_id_t,
		       rados::cls::lock::locker_info_t> Lockers;
      Lockers lockers;
      ClsLockType lock_type;
      std::string lock_tag;
      r = rados::cls::lock::get_lock_info(&ictx->md_ctx, ictx->header_oid,
                                          RBD_LOCK_NAME, &lockers, &lock_type,
                                          &lock_tag);
      if (r < 0) {
        lderr(ictx->cct) << "unable to retrieve lock info: " << cpp_strerror(r)
          	       << dendl;
        return r;
      }

      std::string client_address;
      for (Lockers::iterator it = lockers.begin();
           it != lockers.end(); ++it) {
        if (it->first.locker == lock_client) {
          client_address = stringify(it->second.addr);
          break;
        }
      }
      if (client_address.empty()) {
        return -ENOENT;
      }

      RWLock::RLocker locker(ictx->md_lock);
      librados::Rados rados(ictx->md_ctx);
      r = rados.blacklist_add(client_address,
			      ictx->blacklist_expire_seconds);
      if (r < 0) {
        lderr(ictx->cct) << "unable to blacklist client: " << cpp_strerror(r)
          	       << dendl;
        return r;
      }
    }

    r = rados::cls::lock::break_lock(&ictx->md_ctx, ictx->header_oid,
				     RBD_LOCK_NAME, cookie, lock_client);
    if (r < 0)
      return r;
    ictx->notify_update();
    return 0;
  }

  void rbd_ctx_cb(completion_t cb, void *arg)
  {
    Context *ctx = reinterpret_cast<Context *>(arg);
    auto comp = reinterpret_cast<io::AioCompletion *>(cb);
    ctx->complete(comp->get_return_value());
    comp->release();
  }

  int64_t read_iterate(ImageCtx *ictx, uint64_t off, uint64_t len,
		       int (*cb)(uint64_t, size_t, const char *, void *),
		       void *arg)
  {
    utime_t start_time, elapsed;

    ldout(ictx->cct, 20) << "read_iterate " << ictx << " off = " << off
			 << " len = " << len << dendl;

    int r = ictx->state->refresh_if_required();
    if (r < 0)
      return r;

    uint64_t mylen = len;
    ictx->snap_lock.get_read();
    r = clip_io(ictx, off, &mylen);
    ictx->snap_lock.put_read();
    if (r < 0)
      return r;

    int64_t total_read = 0;
    uint64_t period = ictx->get_stripe_period();
    uint64_t left = mylen;

    ZTracer::Trace trace;
    if (ictx->blkin_trace_all) {
      trace.init("read_iterate", &ictx->trace_endpoint);
    }

    RWLock::RLocker owner_locker(ictx->owner_lock);
    start_time = ceph_clock_now();
    while (left > 0) {
      uint64_t period_off = off - (off % period);
      uint64_t read_len = min(period_off + period - off, left);

      bufferlist bl;

      C_SaferCond ctx;
      auto c = io::AioCompletion::create_and_start(&ctx, ictx,
                                                   io::AIO_TYPE_READ);
      io::ImageRequest<>::aio_read(ictx, c, {{off, read_len}},
                                   io::ReadResult{&bl}, 0, std::move(trace));

      int ret = ctx.wait();
      if (ret < 0) {
        return ret;
      }

      r = cb(total_read, ret, bl.c_str(), arg);
      if (r < 0) {
	return r;
      }

      total_read += ret;
      left -= ret;
      off += ret;
    }

    elapsed = ceph_clock_now() - start_time;
    ictx->perfcounter->tinc(l_librbd_rd_latency, elapsed);
    ictx->perfcounter->inc(l_librbd_rd);
    ictx->perfcounter->inc(l_librbd_rd_bytes, mylen);
    return total_read;
  }

  // validate extent against image size; clip to image size if necessary
  int clip_io(ImageCtx *ictx, uint64_t off, uint64_t *len)
  {
    assert(ictx->snap_lock.is_locked());
    uint64_t image_size = ictx->get_image_size(ictx->snap_id);
    bool snap_exists = ictx->snap_exists;

    if (!snap_exists)
      return -ENOENT;

    // special-case "len == 0" requests: always valid
    if (*len == 0)
      return 0;

    // can't start past end
    if (off >= image_size)
      return -EINVAL;

    // clip requests that extend past end to just end
    if ((off + *len) > image_size)
      *len = (size_t)(image_size - off);

    return 0;
  }

  int flush(ImageCtx *ictx)
  {
    CephContext *cct = ictx->cct;
    ldout(cct, 20) << "flush " << ictx << dendl;

    int r = ictx->state->refresh_if_required();
    if (r < 0) {
      return r;
    }

    ictx->user_flushed();
    C_SaferCond ctx;
    {
      RWLock::RLocker owner_locker(ictx->owner_lock);
      ictx->flush(&ctx);
    }
    r = ctx.wait();

    ictx->perfcounter->inc(l_librbd_flush);
    return r;
  }

  int invalidate_cache(ImageCtx *ictx)
  {
    CephContext *cct = ictx->cct;
    ldout(cct, 20) << "invalidate_cache " << ictx << dendl;

    int r = ictx->state->refresh_if_required();
    if (r < 0) {
      return r;
    }

    RWLock::RLocker owner_locker(ictx->owner_lock);
    RWLock::WLocker md_locker(ictx->md_lock);
    r = ictx->invalidate_cache(false);
    ictx->perfcounter->inc(l_librbd_invalidate_cache);
    return r;
  }

  int poll_io_events(ImageCtx *ictx, io::AioCompletion **comps, int numcomp)
  {
    if (numcomp <= 0)
      return -EINVAL;
    CephContext *cct = ictx->cct;
    ldout(cct, 20) << __func__ << " " << ictx << " numcomp = " << numcomp
                   << dendl;
    int i = 0;
    Mutex::Locker l(ictx->completed_reqs_lock);
    while (i < numcomp) {
      if (ictx->completed_reqs.empty())
        break;
      comps[i++] = ictx->completed_reqs.front();
      ictx->completed_reqs.pop_front();
    }
    return i;
  }

  int metadata_get(ImageCtx *ictx, const string &key, string *value)
  {
    CephContext *cct = ictx->cct;
    ldout(cct, 20) << "metadata_get " << ictx << " key=" << key << dendl;

    int r = ictx->state->refresh_if_required();
    if (r < 0) {
      return r;
    }

    return cls_client::metadata_get(&ictx->md_ctx, ictx->header_oid, key, value);
  }

  int metadata_list(ImageCtx *ictx, const string &start, uint64_t max, map<string, bufferlist> *pairs)
  {
    CephContext *cct = ictx->cct;
    ldout(cct, 20) << "metadata_list " << ictx << dendl;

    int r = ictx->state->refresh_if_required();
    if (r < 0) {
      return r;
    }

    return cls_client::metadata_list(&ictx->md_ctx, ictx->header_oid, start, max, pairs);
  }

  struct C_RBD_Readahead : public Context {
    ImageCtx *ictx;
    object_t oid;
    uint64_t offset;
    uint64_t length;
    C_RBD_Readahead(ImageCtx *ictx, object_t oid, uint64_t offset, uint64_t length)
      : ictx(ictx), oid(oid), offset(offset), length(length) { }
    void finish(int r) override {
      ldout(ictx->cct, 20) << "C_RBD_Readahead on " << oid << ": " << offset << "+" << length << dendl;
      ictx->readahead.dec_pending();
    }
  };

  void readahead(ImageCtx *ictx,
                 const vector<pair<uint64_t,uint64_t> >& image_extents)
  {
    uint64_t total_bytes = 0;
    for (vector<pair<uint64_t,uint64_t> >::const_iterator p = image_extents.begin();
	 p != image_extents.end();
	 ++p) {
      total_bytes += p->second;
    }
    
    ictx->md_lock.get_write();
    bool abort = ictx->readahead_disable_after_bytes != 0 &&
      ictx->total_bytes_read > ictx->readahead_disable_after_bytes;
    if (abort) {
      ictx->md_lock.put_write();
      return;
    }
    ictx->total_bytes_read += total_bytes;
    ictx->snap_lock.get_read();
    uint64_t image_size = ictx->get_image_size(ictx->snap_id);
    ictx->snap_lock.put_read();
    ictx->md_lock.put_write();
 
    pair<uint64_t, uint64_t> readahead_extent = ictx->readahead.update(image_extents, image_size);
    uint64_t readahead_offset = readahead_extent.first;
    uint64_t readahead_length = readahead_extent.second;

    if (readahead_length > 0) {
      ldout(ictx->cct, 20) << "(readahead logical) " << readahead_offset << "~" << readahead_length << dendl;
      map<object_t,vector<ObjectExtent> > readahead_object_extents;
      Striper::file_to_extents(ictx->cct, ictx->format_string, &ictx->layout,
			       readahead_offset, readahead_length, 0, readahead_object_extents);
      for (map<object_t,vector<ObjectExtent> >::iterator p = readahead_object_extents.begin(); p != readahead_object_extents.end(); ++p) {
	for (vector<ObjectExtent>::iterator q = p->second.begin(); q != p->second.end(); ++q) {
	  ldout(ictx->cct, 20) << "(readahead) oid " << q->oid << " " << q->offset << "~" << q->length << dendl;

	  Context *req_comp = new C_RBD_Readahead(ictx, q->oid, q->offset, q->length);
	  ictx->readahead.inc_pending();
	  ictx->aio_read_from_cache(q->oid, q->objectno, NULL,
				    q->length, q->offset,
				    req_comp, 0, nullptr);
	}
      }
      ictx->perfcounter->inc(l_librbd_readahead);
      ictx->perfcounter->inc(l_librbd_readahead_bytes, readahead_length);
    }
  }



}