add subtree-ish sources for 12.0.3

[ceph.git] / ceph / src / os / filestore / FileStore.cc

// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
// vim: ts=8 sw=2 smarttab
/*
 * Ceph - scalable distributed file system
 *
 * Copyright (C) 2004-2006 Sage Weil <sage@newdream.net>
 * Copyright (c) 2015 Hewlett-Packard Development Company, L.P.
 *
 * This is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License version 2.1, as published by the Free Software
 * Foundation.  See file COPYING.
 *
 */
#include "include/compat.h"
#include "include/int_types.h"
#include "boost/tuple/tuple.hpp"

#include <unistd.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/file.h>
#include <errno.h>
#include <dirent.h>
#include <sys/ioctl.h>

#if defined(__linux__)
#include <linux/fs.h>
#endif

#include <iostream>
#include <map>

#include "include/linux_fiemap.h"

#include "common/xattr.h"
#include "chain_xattr.h"

#if defined(DARWIN) || defined(__FreeBSD__)
#include <sys/param.h>
#include <sys/mount.h>
#endif // DARWIN


#include <fstream>
#include <sstream>

#include "FileStore.h"
#include "GenericFileStoreBackend.h"
#include "BtrfsFileStoreBackend.h"
#include "XfsFileStoreBackend.h"
#include "ZFSFileStoreBackend.h"
#include "common/BackTrace.h"
#include "include/types.h"
#include "FileJournal.h"

#include "osd/osd_types.h"
#include "include/color.h"
#include "include/buffer.h"

#include "common/Timer.h"
#include "common/debug.h"
#include "common/errno.h"
#include "common/run_cmd.h"
#include "common/safe_io.h"
#include "common/perf_counters.h"
#include "common/sync_filesystem.h"
#include "common/fd.h"
#include "HashIndex.h"
#include "DBObjectMap.h"
#include "kv/KeyValueDB.h"

#include "common/ceph_crypto.h"
using ceph::crypto::SHA1;

#include "include/assert.h"

#include "common/config.h"
#include "common/blkdev.h"

#ifdef WITH_LTTNG
#define TRACEPOINT_DEFINE
#define TRACEPOINT_PROBE_DYNAMIC_LINKAGE
#include "tracing/objectstore.h"
#undef TRACEPOINT_PROBE_DYNAMIC_LINKAGE
#undef TRACEPOINT_DEFINE
#else
#define tracepoint(...)
#endif

#define dout_context cct
#define dout_subsys ceph_subsys_filestore
#undef dout_prefix
#define dout_prefix *_dout << "filestore(" << basedir << ") "

#define COMMIT_SNAP_ITEM "snap_%llu"
#define CLUSTER_SNAP_ITEM "clustersnap_%s"

#define REPLAY_GUARD_XATTR "user.cephos.seq"
#define GLOBAL_REPLAY_GUARD_XATTR "user.cephos.gseq"

// XATTR_SPILL_OUT_NAME as a xattr is used to maintain that indicates whether
// xattrs spill over into DBObjectMap, if XATTR_SPILL_OUT_NAME exists in file
// xattrs and the value is "no", it indicates no xattrs in DBObjectMap
#define XATTR_SPILL_OUT_NAME "user.cephos.spill_out"
#define XATTR_NO_SPILL_OUT "0"
#define XATTR_SPILL_OUT "1"

//Initial features in new superblock.
static CompatSet get_fs_initial_compat_set() {
  CompatSet::FeatureSet ceph_osd_feature_compat;
  CompatSet::FeatureSet ceph_osd_feature_ro_compat;
  CompatSet::FeatureSet ceph_osd_feature_incompat;
  return CompatSet(ceph_osd_feature_compat, ceph_osd_feature_ro_compat,
                   ceph_osd_feature_incompat);
}

//Features are added here that this FileStore supports.
static CompatSet get_fs_supported_compat_set() {
  CompatSet compat =  get_fs_initial_compat_set();
  //Any features here can be set in code, but not in initial superblock
  compat.incompat.insert(CEPH_FS_FEATURE_INCOMPAT_SHARDS);
  return compat;
}

int FileStore::validate_hobject_key(const hobject_t &obj) const
{
  unsigned len = LFNIndex::get_max_escaped_name_len(obj);
  return len > m_filestore_max_xattr_value_size ? -ENAMETOOLONG : 0;
}

int FileStore::get_block_device_fsid(CephContext* cct, const string& path,
                                     uuid_d *fsid)
{
  // make sure we don't try to use aio or direct_io (and get annoying
  // error messages from failing to do so); performance implications
  // should be irrelevant for this use
  FileJournal j(cct, *fsid, 0, 0, path.c_str(), false, false);
  return j.peek_fsid(*fsid);
}

void FileStore::FSPerfTracker::update_from_perfcounters(
  PerfCounters &logger)
{
  os_commit_latency.consume_next(
    logger.get_tavg_ms(
      l_filestore_journal_latency));
  os_apply_latency.consume_next(
    logger.get_tavg_ms(
      l_filestore_apply_latency));
}


ostream& operator<<(ostream& out, const FileStore::OpSequencer& s)
{
  return out << *s.parent;
}

int FileStore::get_cdir(const coll_t& cid, char *s, int len)
{
  const string &cid_str(cid.to_str());
  return snprintf(s, len, "%s/current/%s", basedir.c_str(), cid_str.c_str());
}

int FileStore::get_index(const coll_t& cid, Index *index)
{
  int r = index_manager.get_index(cid, basedir, index);
  assert(!m_filestore_fail_eio || r != -EIO);
  return r;
}

int FileStore::init_index(const coll_t& cid)
{
  char path[PATH_MAX];
  get_cdir(cid, path, sizeof(path));
  int r = index_manager.init_index(cid, path, target_version);
  assert(!m_filestore_fail_eio || r != -EIO);
  return r;
}

int FileStore::lfn_find(const ghobject_t& oid, const Index& index, IndexedPath *path)
{
  IndexedPath path2;
  if (!path)
    path = &path2;
  int r, exist;
  assert(NULL != index.index);
  r = (index.index)->lookup(oid, path, &exist);
  if (r < 0) {
    assert(!m_filestore_fail_eio || r != -EIO);
    return r;
  }
  if (!exist)
    return -ENOENT;
  return 0;
}

int FileStore::lfn_truncate(const coll_t& cid, const ghobject_t& oid, off_t length)
{
  FDRef fd;
  int r = lfn_open(cid, oid, false, &fd);
  if (r < 0)
    return r;
  r = ::ftruncate(**fd, length);
  if (r < 0)
    r = -errno;
  if (r >= 0 && m_filestore_sloppy_crc) {
    int rc = backend->_crc_update_truncate(**fd, length);
    assert(rc >= 0);
  }
  lfn_close(fd);
  assert(!m_filestore_fail_eio || r != -EIO);
  return r;
}

int FileStore::lfn_stat(const coll_t& cid, const ghobject_t& oid, struct stat *buf)
{
  IndexedPath path;
  Index index;
  int r = get_index(cid, &index);
  if (r < 0)
    return r;

  assert(NULL != index.index);
  RWLock::RLocker l((index.index)->access_lock);

  r = lfn_find(oid, index, &path);
  if (r < 0)
    return r;
  r = ::stat(path->path(), buf);
  if (r < 0)
    r = -errno;
  return r;
}

int FileStore::lfn_open(const coll_t& cid,
                        const ghobject_t& oid,
                        bool create,
                        FDRef *outfd,
                        Index *index)
{
  assert(outfd);
  int r = 0;
  bool need_lock = true;
  int flags = O_RDWR;

  if (create)
    flags |= O_CREAT;
  if (cct->_conf->filestore_odsync_write) {
    flags |= O_DSYNC;
  }

  Index index2;
  if (!index) {
    index = &index2;
  }
  if (!((*index).index)) {
    r = get_index(cid, index);
    if (r < 0) {
      dout(10) << __func__ << " could not get index r = " << r << dendl;
      return r;
    }
  } else {
    need_lock = false;
  }

  int fd, exist;
  assert(NULL != (*index).index);
  if (need_lock) {
    ((*index).index)->access_lock.get_write();
  }
  if (!replaying) {
    *outfd = fdcache.lookup(oid);
    if (*outfd) {
      if (need_lock) {
        ((*index).index)->access_lock.put_write();
      }
      return 0;
    }
  }


  IndexedPath path2;
  IndexedPath *path = &path2;

  r = (*index)->lookup(oid, path, &exist);
  if (r < 0) {
    derr << "could not find " << oid << " in index: "
      << cpp_strerror(-r) << dendl;
    goto fail;
  }

  r = ::open((*path)->path(), flags, 0644);
  if (r < 0) {
    r = -errno;
    dout(10) << "error opening file " << (*path)->path() << " with flags="
      << flags << ": " << cpp_strerror(-r) << dendl;
    goto fail;
  }
  fd = r;
  if (create && (!exist)) {
    r = (*index)->created(oid, (*path)->path());
    if (r < 0) {
      VOID_TEMP_FAILURE_RETRY(::close(fd));
      derr << "error creating " << oid << " (" << (*path)->path()
          << ") in index: " << cpp_strerror(-r) << dendl;
      goto fail;
    }
    r = chain_fsetxattr<true, true>(
      fd, XATTR_SPILL_OUT_NAME,
      XATTR_NO_SPILL_OUT, sizeof(XATTR_NO_SPILL_OUT));
    if (r < 0) {
      VOID_TEMP_FAILURE_RETRY(::close(fd));
      derr << "error setting spillout xattr for oid " << oid << " (" << (*path)->path()
                     << "):" << cpp_strerror(-r) << dendl;
      goto fail;
    }
  }

  if (!replaying) {
    bool existed;
    *outfd = fdcache.add(oid, fd, &existed);
    if (existed) {
      TEMP_FAILURE_RETRY(::close(fd));
    }
  } else {
    *outfd = std::make_shared<FDCache::FD>(fd);
  }

  if (need_lock) {
    ((*index).index)->access_lock.put_write();
  }

  return 0;

 fail:

  if (need_lock) {
    ((*index).index)->access_lock.put_write();
  }

  assert(!m_filestore_fail_eio || r != -EIO);
  return r;
}

void FileStore::lfn_close(FDRef fd)
{
}

int FileStore::lfn_link(const coll_t& c, const coll_t& newcid, const ghobject_t& o, const ghobject_t& newoid)
{
  Index index_new, index_old;
  IndexedPath path_new, path_old;
  int exist;
  int r;
  bool index_same = false;
  if (c < newcid) {
    r = get_index(newcid, &index_new);
    if (r < 0)
      return r;
    r = get_index(c, &index_old);
    if (r < 0)
      return r;
  } else if (c == newcid) {
    r = get_index(c, &index_old);
    if (r < 0)
      return r;
    index_new = index_old;
    index_same = true;
  } else {
    r = get_index(c, &index_old);
    if (r < 0)
      return r;
    r = get_index(newcid, &index_new);
    if (r < 0)
      return r;
  }

  assert(NULL != index_old.index);
  assert(NULL != index_new.index);

  if (!index_same) {

    RWLock::RLocker l1((index_old.index)->access_lock);

    r = index_old->lookup(o, &path_old, &exist);
    if (r < 0) {
      assert(!m_filestore_fail_eio || r != -EIO);
      return r;
    }
    if (!exist)
      return -ENOENT;

    RWLock::WLocker l2((index_new.index)->access_lock);

    r = index_new->lookup(newoid, &path_new, &exist);
    if (r < 0) {
      assert(!m_filestore_fail_eio || r != -EIO);
      return r;
    }
    if (exist)
      return -EEXIST;

    dout(25) << "lfn_link path_old: " << path_old << dendl;
    dout(25) << "lfn_link path_new: " << path_new << dendl;
    r = ::link(path_old->path(), path_new->path());
    if (r < 0)
      return -errno;

    r = index_new->created(newoid, path_new->path());
    if (r < 0) {
      assert(!m_filestore_fail_eio || r != -EIO);
      return r;
    }
  } else {
    RWLock::WLocker l1((index_old.index)->access_lock);

    r = index_old->lookup(o, &path_old, &exist);
    if (r < 0) {
      assert(!m_filestore_fail_eio || r != -EIO);
      return r;
    }
    if (!exist)
      return -ENOENT;

    r = index_new->lookup(newoid, &path_new, &exist);
    if (r < 0) {
      assert(!m_filestore_fail_eio || r != -EIO);
      return r;
    }
    if (exist)
      return -EEXIST;

    dout(25) << "lfn_link path_old: " << path_old << dendl;
    dout(25) << "lfn_link path_new: " << path_new << dendl;
    r = ::link(path_old->path(), path_new->path());
    if (r < 0)
      return -errno;

    // make sure old fd for unlinked/overwritten file is gone
    fdcache.clear(newoid);

    r = index_new->created(newoid, path_new->path());
    if (r < 0) {
      assert(!m_filestore_fail_eio || r != -EIO);
      return r;
    }
  }
  return 0;
}

int FileStore::lfn_unlink(const coll_t& cid, const ghobject_t& o,
                          const SequencerPosition &spos,
                          bool force_clear_omap)
{
  Index index;
  int r = get_index(cid, &index);
  if (r < 0) {
    dout(25) << __func__ << " get_index failed " << cpp_strerror(r) << dendl;
    return r;
  }

  assert(NULL != index.index);
  RWLock::WLocker l((index.index)->access_lock);

  {
    IndexedPath path;
    int hardlink;
    r = index->lookup(o, &path, &hardlink);
    if (r < 0) {
      assert(!m_filestore_fail_eio || r != -EIO);
      return r;
    }

    if (!force_clear_omap) {
      if (hardlink == 0 || hardlink == 1) {
          force_clear_omap = true;
      }
    }
    if (force_clear_omap) {
      dout(20) << __func__ << ": clearing omap on " << o
               << " in cid " << cid << dendl;
      r = object_map->clear(o, &spos);
      if (r < 0 && r != -ENOENT) {
        dout(25) << __func__ << " omap clear failed " << cpp_strerror(r) << dendl;
        assert(!m_filestore_fail_eio || r != -EIO);
        return r;
      }
      if (cct->_conf->filestore_debug_inject_read_err) {
        debug_obj_on_delete(o);
      }
      if (!m_disable_wbthrottle) {
        wbthrottle.clear_object(o); // should be only non-cache ref
      }
      fdcache.clear(o);
    } else {
      /* Ensure that replay of this op doesn't result in the object_map
       * going away.
       */
      if (!backend->can_checkpoint())
        object_map->sync(&o, &spos);
    }
    if (hardlink == 0) {
      if (!m_disable_wbthrottle) {
        wbthrottle.clear_object(o); // should be only non-cache ref
      }
      return 0;
    }
  }
  r = index->unlink(o);
  if (r < 0) {
    dout(25) << __func__ << " index unlink failed " << cpp_strerror(r) << dendl;
    return r;
  }
  return 0;
}

FileStore::FileStore(CephContext* cct, const std::string &base,
                     const std::string &jdev, osflagbits_t flags,
                     const char *name, bool do_update) :
  JournalingObjectStore(cct, base),
  internal_name(name),
  basedir(base), journalpath(jdev),
  generic_flags(flags),
  blk_size(0),
  fsid_fd(-1), op_fd(-1),
  basedir_fd(-1), current_fd(-1),
  backend(NULL),
  index_manager(cct, do_update),
  lock("FileStore::lock"),
  force_sync(false),
  sync_entry_timeo_lock("FileStore::sync_entry_timeo_lock"),
  timer(cct, sync_entry_timeo_lock),
  stop(false), sync_thread(this),
  fdcache(cct),
  wbthrottle(cct),
  next_osr_id(0),
  m_disable_wbthrottle(cct->_conf->filestore_odsync_write ||
                      !cct->_conf->filestore_wbthrottle_enable),
  throttle_ops(cct, "filestore_ops", cct->_conf->filestore_caller_concurrency),
  throttle_bytes(cct, "filestore_bytes", cct->_conf->filestore_caller_concurrency),
  m_ondisk_finisher_num(cct->_conf->filestore_ondisk_finisher_threads),
  m_apply_finisher_num(cct->_conf->filestore_apply_finisher_threads),
  op_tp(cct, "FileStore::op_tp", "tp_fstore_op", cct->_conf->filestore_op_threads, "filestore_op_threads"),
  op_wq(this, cct->_conf->filestore_op_thread_timeout,
        cct->_conf->filestore_op_thread_suicide_timeout, &op_tp),
  logger(NULL),
  trace_endpoint("0.0.0.0", 0, "FileStore"),
  read_error_lock("FileStore::read_error_lock"),
  m_filestore_commit_timeout(cct->_conf->filestore_commit_timeout),
  m_filestore_journal_parallel(cct->_conf->filestore_journal_parallel ),
  m_filestore_journal_trailing(cct->_conf->filestore_journal_trailing),
  m_filestore_journal_writeahead(cct->_conf->filestore_journal_writeahead),
  m_filestore_fiemap_threshold(cct->_conf->filestore_fiemap_threshold),
  m_filestore_max_sync_interval(cct->_conf->filestore_max_sync_interval),
  m_filestore_min_sync_interval(cct->_conf->filestore_min_sync_interval),
  m_filestore_fail_eio(cct->_conf->filestore_fail_eio),
  m_filestore_fadvise(cct->_conf->filestore_fadvise),
  do_update(do_update),
  m_journal_dio(cct->_conf->journal_dio),
  m_journal_aio(cct->_conf->journal_aio),
  m_journal_force_aio(cct->_conf->journal_force_aio),
  m_osd_rollback_to_cluster_snap(cct->_conf->osd_rollback_to_cluster_snap),
  m_osd_use_stale_snap(cct->_conf->osd_use_stale_snap),
  m_filestore_do_dump(false),
  m_filestore_dump_fmt(true),
  m_filestore_sloppy_crc(cct->_conf->filestore_sloppy_crc),
  m_filestore_sloppy_crc_block_size(cct->_conf->filestore_sloppy_crc_block_size),
  m_filestore_max_alloc_hint_size(cct->_conf->filestore_max_alloc_hint_size),
  m_fs_type(0),
  m_filestore_max_inline_xattr_size(0),
  m_filestore_max_inline_xattrs(0),
  m_filestore_max_xattr_value_size(0)
{
  m_filestore_kill_at.set(cct->_conf->filestore_kill_at);
  for (int i = 0; i < m_ondisk_finisher_num; ++i) {
    ostringstream oss;
    oss << "filestore-ondisk-" << i;
    Finisher *f = new Finisher(cct, oss.str(), "fn_odsk_fstore");
    ondisk_finishers.push_back(f);
  }
  for (int i = 0; i < m_apply_finisher_num; ++i) {
    ostringstream oss;
    oss << "filestore-apply-" << i;
    Finisher *f = new Finisher(cct, oss.str(), "fn_appl_fstore");
    apply_finishers.push_back(f);
  }

  ostringstream oss;
  oss << basedir << "/current";
  current_fn = oss.str();

  ostringstream sss;
  sss << basedir << "/current/commit_op_seq";
  current_op_seq_fn = sss.str();

  ostringstream omss;
  if (cct->_conf->filestore_omap_backend_path != "") {
      omap_dir = cct->_conf->filestore_omap_backend_path;
  } else {
      omss << basedir << "/current/omap";
      omap_dir = omss.str();
  }

  // initialize logger
  PerfCountersBuilder plb(cct, internal_name, l_filestore_first, l_filestore_last);

  plb.add_u64(l_filestore_journal_queue_ops, "journal_queue_ops", "Operations in journal queue");
  plb.add_u64(l_filestore_journal_ops, "journal_ops", "Active journal entries to be applied");
  plb.add_u64(l_filestore_journal_queue_bytes, "journal_queue_bytes", "Size of journal queue");
  plb.add_u64(l_filestore_journal_bytes, "journal_bytes", "Active journal operation size to be applied");
  plb.add_time_avg(l_filestore_journal_latency, "journal_latency", "Average journal queue completing latency");
  plb.add_u64_counter(l_filestore_journal_wr, "journal_wr", "Journal write IOs");
  plb.add_u64_avg(l_filestore_journal_wr_bytes, "journal_wr_bytes", "Journal data written");
  plb.add_u64(l_filestore_op_queue_max_ops, "op_queue_max_ops", "Max operations in writing to FS queue");
  plb.add_u64(l_filestore_op_queue_ops, "op_queue_ops", "Operations in writing to FS queue");
  plb.add_u64_counter(l_filestore_ops, "ops", "Operations written to store");
  plb.add_u64(l_filestore_op_queue_max_bytes, "op_queue_max_bytes", "Max data in writing to FS queue");
  plb.add_u64(l_filestore_op_queue_bytes, "op_queue_bytes", "Size of writing to FS queue");
  plb.add_u64_counter(l_filestore_bytes, "bytes", "Data written to store");
  plb.add_time_avg(l_filestore_apply_latency, "apply_latency", "Apply latency");
  plb.add_u64(l_filestore_committing, "committing", "Is currently committing");

  plb.add_u64_counter(l_filestore_commitcycle, "commitcycle", "Commit cycles");
  plb.add_time_avg(l_filestore_commitcycle_interval, "commitcycle_interval", "Average interval between commits");
  plb.add_time_avg(l_filestore_commitcycle_latency, "commitcycle_latency", "Average latency of commit");
  plb.add_u64_counter(l_filestore_journal_full, "journal_full", "Journal writes while full");
  plb.add_time_avg(l_filestore_queue_transaction_latency_avg, "queue_transaction_latency_avg", "Store operation queue latency");

  logger = plb.create_perf_counters();

  cct->get_perfcounters_collection()->add(logger);
  cct->_conf->add_observer(this);

  superblock.compat_features = get_fs_initial_compat_set();
}

FileStore::~FileStore()
{
  for (vector<Finisher*>::iterator it = ondisk_finishers.begin(); it != ondisk_finishers.end(); ++it) {
    delete *it;
    *it = NULL;
  }
  for (vector<Finisher*>::iterator it = apply_finishers.begin(); it != apply_finishers.end(); ++it) {
    delete *it;
    *it = NULL;
  }
  cct->_conf->remove_observer(this);
  cct->get_perfcounters_collection()->remove(logger);

  if (journal)
    journal->logger = NULL;
  delete logger;

  if (m_filestore_do_dump) {
    dump_stop();
  }
}

static void get_attrname(const char *name, char *buf, int len)
{
  snprintf(buf, len, "user.ceph.%s", name);
}

bool parse_attrname(char **name)
{
  if (strncmp(*name, "user.ceph.", 10) == 0) {
    *name += 10;
    return true;
  }
  return false;
}

void FileStore::collect_metadata(map<string,string> *pm)
{
  char partition_path[PATH_MAX];
  char dev_node[PATH_MAX];
  int rc = 0;

  (*pm)["filestore_backend"] = backend->get_name();
  ostringstream ss;
  ss << "0x" << std::hex << m_fs_type << std::dec;
  (*pm)["filestore_f_type"] = ss.str();

  if (cct->_conf->filestore_collect_device_partition_information) {
    rc = get_device_by_uuid(get_fsid(), "PARTUUID", partition_path,
          dev_node);
  } else {
    rc = -EINVAL;
  }

  switch (rc) {
    case -EOPNOTSUPP:
    case -EINVAL:
      (*pm)["backend_filestore_partition_path"] = "unknown";
      (*pm)["backend_filestore_dev_node"] = "unknown";
      break;
    case -ENODEV:
      (*pm)["backend_filestore_partition_path"] = string(partition_path);
      (*pm)["backend_filestore_dev_node"] = "unknown";
      break;
    default:
      (*pm)["backend_filestore_partition_path"] = string(partition_path);
      (*pm)["backend_filestore_dev_node"] = string(dev_node);
  }
}

int FileStore::statfs(struct store_statfs_t *buf0)
{
  struct statfs buf;
  buf0->reset();
  if (::statfs(basedir.c_str(), &buf) < 0) {
    int r = -errno;
    assert(!m_filestore_fail_eio || r != -EIO);
    assert(r != -ENOENT);
    return r;
  }
  buf0->total = buf.f_blocks * buf.f_bsize;
  buf0->available = buf.f_bavail * buf.f_bsize;
  // Adjust for writes pending in the journal
  if (journal) {
    uint64_t estimate = journal->get_journal_size_estimate();
    if (buf0->available > estimate)
      buf0->available -= estimate;
    else
      buf0->available = 0;
  }
  return 0;
}


void FileStore::new_journal()
{
  if (journalpath.length()) {
    dout(10) << "open_journal at " << journalpath << dendl;
    journal = new FileJournal(cct, fsid, &finisher, &sync_cond,
                              journalpath.c_str(),
                              m_journal_dio, m_journal_aio,
                              m_journal_force_aio);
    if (journal)
      journal->logger = logger;
  }
  return;
}

int FileStore::dump_journal(ostream& out)
{
  int r;

  if (!journalpath.length())
    return -EINVAL;

  FileJournal *journal = new FileJournal(cct, fsid, &finisher, &sync_cond, journalpath.c_str(), m_journal_dio);
  r = journal->dump(out);
  delete journal;
  return r;
}

FileStoreBackend *FileStoreBackend::create(long f_type, FileStore *fs)
{
  switch (f_type) {
#if defined(__linux__)
  case BTRFS_SUPER_MAGIC:
    return new BtrfsFileStoreBackend(fs);
# ifdef HAVE_LIBXFS
  case XFS_SUPER_MAGIC:
    return new XfsFileStoreBackend(fs);
# endif
#endif
#ifdef HAVE_LIBZFS
  case ZFS_SUPER_MAGIC:
    return new ZFSFileStoreBackend(fs);
#endif
  default:
    return new GenericFileStoreBackend(fs);
  }
}

void FileStore::create_backend(long f_type)
{
  m_fs_type = f_type;

  assert(backend == NULL);
  backend = FileStoreBackend::create(f_type, this);

  dout(0) << "backend " << backend->get_name()
          << " (magic 0x" << std::hex << f_type << std::dec << ")"
          << dendl;

  switch (f_type) {
#if defined(__linux__)
  case BTRFS_SUPER_MAGIC:
    if (!m_disable_wbthrottle){
      wbthrottle.set_fs(WBThrottle::BTRFS);
    }
    break;

  case XFS_SUPER_MAGIC:
    // wbthrottle is constructed with fs(WBThrottle::XFS)
    break;
#endif
  }

  set_xattr_limits_via_conf();
}

int FileStore::mkfs()
{
  int ret = 0;
  char fsid_fn[PATH_MAX];
  char fsid_str[40];
  uuid_d old_fsid;
  uuid_d old_omap_fsid;

  dout(1) << "mkfs in " << basedir << dendl;
  basedir_fd = ::open(basedir.c_str(), O_RDONLY);
  if (basedir_fd < 0) {
    ret = -errno;
    derr << "mkfs failed to open base dir " << basedir << ": " << cpp_strerror(ret) << dendl;
    return ret;
  }

  // open+lock fsid
  snprintf(fsid_fn, sizeof(fsid_fn), "%s/fsid", basedir.c_str());
  fsid_fd = ::open(fsid_fn, O_RDWR|O_CREAT, 0644);
  if (fsid_fd < 0) {
    ret = -errno;
    derr << "mkfs: failed to open " << fsid_fn << ": " << cpp_strerror(ret) << dendl;
    goto close_basedir_fd;
  }

  if (lock_fsid() < 0) {
    ret = -EBUSY;
    goto close_fsid_fd;
  }

  if (read_fsid(fsid_fd, &old_fsid) < 0 || old_fsid.is_zero()) {
    if (fsid.is_zero()) {
      fsid.generate_random();
      dout(1) << "mkfs generated fsid " << fsid << dendl;
    } else {
      dout(1) << "mkfs using provided fsid " << fsid << dendl;
    }

    fsid.print(fsid_str);
    strcat(fsid_str, "\n");
    ret = ::ftruncate(fsid_fd, 0);
    if (ret < 0) {
      ret = -errno;
      derr << "mkfs: failed to truncate fsid: "
           << cpp_strerror(ret) << dendl;
      goto close_fsid_fd;
    }
    ret = safe_write(fsid_fd, fsid_str, strlen(fsid_str));
    if (ret < 0) {
      derr << "mkfs: failed to write fsid: "
           << cpp_strerror(ret) << dendl;
      goto close_fsid_fd;
    }
    if (::fsync(fsid_fd) < 0) {
      ret = -errno;
      derr << "mkfs: close failed: can't write fsid: "
           << cpp_strerror(ret) << dendl;
      goto close_fsid_fd;
    }
    dout(10) << "mkfs fsid is " << fsid << dendl;
  } else {
    if (!fsid.is_zero() && fsid != old_fsid) {
      derr << "mkfs on-disk fsid " << old_fsid << " != provided " << fsid << dendl;
      ret = -EINVAL;
      goto close_fsid_fd;
    }
    fsid = old_fsid;
    dout(1) << "mkfs fsid is already set to " << fsid << dendl;
  }

  // version stamp
  ret = write_version_stamp();
  if (ret < 0) {
    derr << "mkfs: write_version_stamp() failed: "
         << cpp_strerror(ret) << dendl;
    goto close_fsid_fd;
  }

  // superblock
  superblock.omap_backend = cct->_conf->filestore_omap_backend;
  ret = write_superblock();
  if (ret < 0) {
    derr << "mkfs: write_superblock() failed: "
         << cpp_strerror(ret) << dendl;
    goto close_fsid_fd;
  }

  struct statfs basefs;
  ret = ::fstatfs(basedir_fd, &basefs);
  if (ret < 0) {
    ret = -errno;
    derr << "mkfs cannot fstatfs basedir "
         << cpp_strerror(ret) << dendl;
    goto close_fsid_fd;
  }

  create_backend(basefs.f_type);

  ret = backend->create_current();
  if (ret < 0) {
    derr << "mkfs: failed to create current/ " << cpp_strerror(ret) << dendl;
    goto close_fsid_fd;
  }

  // write initial op_seq
  {
    uint64_t initial_seq = 0;
    int fd = read_op_seq(&initial_seq);
    if (fd < 0) {
      ret = fd;
      derr << "mkfs: failed to create " << current_op_seq_fn << ": "
           << cpp_strerror(ret) << dendl;
      goto close_fsid_fd;
    }
    if (initial_seq == 0) {
      ret = write_op_seq(fd, 1);
      if (ret < 0) {
        VOID_TEMP_FAILURE_RETRY(::close(fd));
        derr << "mkfs: failed to write to " << current_op_seq_fn << ": "
             << cpp_strerror(ret) << dendl;
        goto close_fsid_fd;
      }

      if (backend->can_checkpoint()) {
        // create snap_1 too
        current_fd = ::open(current_fn.c_str(), O_RDONLY);
        assert(current_fd >= 0);
        char s[NAME_MAX];
        snprintf(s, sizeof(s), COMMIT_SNAP_ITEM, 1ull);
        ret = backend->create_checkpoint(s, NULL);
        VOID_TEMP_FAILURE_RETRY(::close(current_fd));
        if (ret < 0 && ret != -EEXIST) {
          VOID_TEMP_FAILURE_RETRY(::close(fd));
          derr << "mkfs: failed to create snap_1: " << cpp_strerror(ret) << dendl;
          goto close_fsid_fd;
        }
      }
    }
    VOID_TEMP_FAILURE_RETRY(::close(fd));
  }
  ret = KeyValueDB::test_init(superblock.omap_backend, omap_dir);
  if (ret < 0) {
    derr << "mkfs failed to create " << cct->_conf->filestore_omap_backend << dendl;
    goto close_fsid_fd;
  }
  // create fsid under omap
  // open+lock fsid
  int omap_fsid_fd;
  char omap_fsid_fn[PATH_MAX];
  snprintf(omap_fsid_fn, sizeof(omap_fsid_fn), "%s/osd_uuid", omap_dir.c_str());
  omap_fsid_fd = ::open(omap_fsid_fn, O_RDWR|O_CREAT, 0644);
  if (omap_fsid_fd < 0) {
    ret = -errno;
    derr << "mkfs: failed to open " << omap_fsid_fn << ": " << cpp_strerror(ret) << dendl;
    goto close_fsid_fd;
  }

  if (read_fsid(omap_fsid_fd, &old_omap_fsid) < 0 || old_omap_fsid.is_zero()) {
    assert(!fsid.is_zero());
    fsid.print(fsid_str);
    strcat(fsid_str, "\n");
    ret = ::ftruncate(omap_fsid_fd, 0);
    if (ret < 0) {
      ret = -errno;
      derr << "mkfs: failed to truncate fsid: "
           << cpp_strerror(ret) << dendl;
      goto close_omap_fsid_fd;
    }
    ret = safe_write(omap_fsid_fd, fsid_str, strlen(fsid_str));
    if (ret < 0) {
      derr << "mkfs: failed to write fsid: "
           << cpp_strerror(ret) << dendl;
      goto close_omap_fsid_fd;
    }
    dout(10) << "mkfs: write success, fsid:" << fsid_str << ", ret:" << ret << dendl;
    if (::fsync(omap_fsid_fd) < 0) {
      ret = -errno;
      derr << "mkfs: close failed: can't write fsid: "
           << cpp_strerror(ret) << dendl;
      goto close_omap_fsid_fd;
    }
    dout(10) << "mkfs omap fsid is " << fsid << dendl;
  } else {
    if (fsid != old_omap_fsid) {
      derr << "FileStore::mkfs: " << omap_fsid_fn
           << " has existed omap fsid " << old_omap_fsid
           << " != expected osd fsid " << fsid
           << dendl;
      ret = -EINVAL;
      goto close_omap_fsid_fd;
    }
    dout(1) << "FileStore::mkfs: omap fsid is already set to " << fsid << dendl;
  }

  dout(1) << cct->_conf->filestore_omap_backend << " db exists/created" << dendl;

  // journal?
  ret = mkjournal();
  if (ret)
    goto close_omap_fsid_fd;

  ret = write_meta("type", "filestore");
  if (ret)
    goto close_omap_fsid_fd;

  dout(1) << "mkfs done in " << basedir << dendl;
  ret = 0;

 close_omap_fsid_fd:
  VOID_TEMP_FAILURE_RETRY(::close(omap_fsid_fd));
 close_fsid_fd:
  VOID_TEMP_FAILURE_RETRY(::close(fsid_fd));
  fsid_fd = -1;
 close_basedir_fd:
  VOID_TEMP_FAILURE_RETRY(::close(basedir_fd));
  delete backend;
  backend = NULL;
  return ret;
}

int FileStore::mkjournal()
{
  // read fsid
  int ret;
  char fn[PATH_MAX];
  snprintf(fn, sizeof(fn), "%s/fsid", basedir.c_str());
  int fd = ::open(fn, O_RDONLY, 0644);
  if (fd < 0) {
    int err = errno;
    derr << "FileStore::mkjournal: open error: " << cpp_strerror(err) << dendl;
    return -err;
  }
  ret = read_fsid(fd, &fsid);
  if (ret < 0) {
    derr << "FileStore::mkjournal: read error: " << cpp_strerror(ret) << dendl;
    VOID_TEMP_FAILURE_RETRY(::close(fd));
    return ret;
  }
  VOID_TEMP_FAILURE_RETRY(::close(fd));

  ret = 0;

  new_journal();
  if (journal) {
    ret = journal->check();
    if (ret < 0) {
      ret = journal->create();
      if (ret)
        derr << "mkjournal error creating journal on " << journalpath
                << ": " << cpp_strerror(ret) << dendl;
      else
        dout(0) << "mkjournal created journal on " << journalpath << dendl;
    }
    delete journal;
    journal = 0;
  }
  return ret;
}

int FileStore::read_fsid(int fd, uuid_d *uuid)
{
  char fsid_str[40];
  memset(fsid_str, 0, sizeof(fsid_str));
  int ret = safe_read(fd, fsid_str, sizeof(fsid_str));
  if (ret < 0)
    return ret;
  if (ret == 8) {
    // old 64-bit fsid... mirror it.
    *(uint64_t*)&uuid->bytes()[0] = *(uint64_t*)fsid_str;
    *(uint64_t*)&uuid->bytes()[8] = *(uint64_t*)fsid_str;
    return 0;
  }

  if (ret > 36)
    fsid_str[36] = 0;
  else
    fsid_str[ret] = 0;
  if (!uuid->parse(fsid_str))
    return -EINVAL;
  return 0;
}

int FileStore::lock_fsid()
{
  struct flock l;
  memset(&l, 0, sizeof(l));
  l.l_type = F_WRLCK;
  l.l_whence = SEEK_SET;
  l.l_start = 0;
  l.l_len = 0;
  int r = ::fcntl(fsid_fd, F_SETLK, &l);
  if (r < 0) {
    int err = errno;
    dout(0) << "lock_fsid failed to lock " << basedir << "/fsid, is another ceph-osd still running? "
            << cpp_strerror(err) << dendl;
    return -err;
  }
  return 0;
}

bool FileStore::test_mount_in_use()
{
  dout(5) << "test_mount basedir " << basedir << " journal " << journalpath << dendl;
  char fn[PATH_MAX];
  snprintf(fn, sizeof(fn), "%s/fsid", basedir.c_str());

  // verify fs isn't in use

  fsid_fd = ::open(fn, O_RDWR, 0644);
  if (fsid_fd < 0)
    return 0;   // no fsid, ok.
  bool inuse = lock_fsid() < 0;
  VOID_TEMP_FAILURE_RETRY(::close(fsid_fd));
  fsid_fd = -1;
  return inuse;
}

int FileStore::_detect_fs()
{
  struct statfs st;
  int r = ::fstatfs(basedir_fd, &st);
  if (r < 0)
    return -errno;

  blk_size = st.f_bsize;

  create_backend(st.f_type);

  r = backend->detect_features();
  if (r < 0) {
    derr << "_detect_fs: detect_features error: " << cpp_strerror(r) << dendl;
    return r;
  }

  // test xattrs
  char fn[PATH_MAX];
  int x = rand();
  int y = x+1;
  snprintf(fn, sizeof(fn), "%s/xattr_test", basedir.c_str());
  int tmpfd = ::open(fn, O_CREAT|O_WRONLY|O_TRUNC, 0700);
  if (tmpfd < 0) {
    int ret = -errno;
    derr << "_detect_fs unable to create " << fn << ": " << cpp_strerror(ret) << dendl;
    return ret;
  }

  int ret = chain_fsetxattr(tmpfd, "user.test", &x, sizeof(x));
  if (ret >= 0)
    ret = chain_fgetxattr(tmpfd, "user.test", &y, sizeof(y));
  if ((ret < 0) || (x != y)) {
    derr << "Extended attributes don't appear to work. ";
    if (ret)
      *_dout << "Got error " + cpp_strerror(ret) + ". ";
    *_dout << "If you are using ext3 or ext4, be sure to mount the underlying "
           << "file system with the 'user_xattr' option." << dendl;
    ::unlink(fn);
    VOID_TEMP_FAILURE_RETRY(::close(tmpfd));
    return -ENOTSUP;
  }

  char buf[1000];
  memset(buf, 0, sizeof(buf)); // shut up valgrind
  chain_fsetxattr(tmpfd, "user.test", &buf, sizeof(buf));
  chain_fsetxattr(tmpfd, "user.test2", &buf, sizeof(buf));
  chain_fsetxattr(tmpfd, "user.test3", &buf, sizeof(buf));
  chain_fsetxattr(tmpfd, "user.test4", &buf, sizeof(buf));
  ret = chain_fsetxattr(tmpfd, "user.test5", &buf, sizeof(buf));
  if (ret == -ENOSPC) {
    dout(0) << "limited size xattrs" << dendl;
  }
  chain_fremovexattr(tmpfd, "user.test");
  chain_fremovexattr(tmpfd, "user.test2");
  chain_fremovexattr(tmpfd, "user.test3");
  chain_fremovexattr(tmpfd, "user.test4");
  chain_fremovexattr(tmpfd, "user.test5");

  ::unlink(fn);
  VOID_TEMP_FAILURE_RETRY(::close(tmpfd));

  return 0;
}

int FileStore::_sanity_check_fs()
{
  // sanity check(s)

  if (((int)m_filestore_journal_writeahead +
      (int)m_filestore_journal_parallel +
      (int)m_filestore_journal_trailing) > 1) {
    dout(0) << "mount ERROR: more than one of filestore journal {writeahead,parallel,trailing} enabled" << dendl;
    cerr << TEXT_RED
         << " ** WARNING: more than one of 'filestore journal {writeahead,parallel,trailing}'\n"
         << "             is enabled in ceph.conf.  You must choose a single journal mode."
         << TEXT_NORMAL << std::endl;
    return -EINVAL;
  }

  if (!backend->can_checkpoint()) {
    if (!journal || !m_filestore_journal_writeahead) {
      dout(0) << "mount WARNING: no btrfs, and no journal in writeahead mode; data may be lost" << dendl;
      cerr << TEXT_RED
           << " ** WARNING: no btrfs AND (no journal OR journal not in writeahead mode)\n"
           << "             For non-btrfs volumes, a writeahead journal is required to\n"
           << "             maintain on-disk consistency in the event of a crash.  Your conf\n"
           << "             should include something like:\n"
           << "        osd journal = /path/to/journal_device_or_file\n"
           << "        filestore journal writeahead = true\n"
           << TEXT_NORMAL;
    }
  }

  if (!journal) {
    dout(0) << "mount WARNING: no journal" << dendl;
    cerr << TEXT_YELLOW
         << " ** WARNING: No osd journal is configured: write latency may be high.\n"
         << "             If you will not be using an osd journal, write latency may be\n"
         << "             relatively high.  It can be reduced somewhat by lowering\n"
         << "             filestore_max_sync_interval, but lower values mean lower write\n"
         << "             throughput, especially with spinning disks.\n"
         << TEXT_NORMAL;
  }

  return 0;
}

int FileStore::write_superblock()
{
  bufferlist bl;
  ::encode(superblock, bl);
  return safe_write_file(basedir.c_str(), "superblock",
      bl.c_str(), bl.length());
}

int FileStore::read_superblock()
{
  bufferptr bp(PATH_MAX);
  int ret = safe_read_file(basedir.c_str(), "superblock",
      bp.c_str(), bp.length());
  if (ret < 0) {
    if (ret == -ENOENT) {
      // If the file doesn't exist write initial CompatSet
      return write_superblock();
    }
    return ret;
  }

  bufferlist bl;
  bl.push_back(std::move(bp));
  bufferlist::iterator i = bl.begin();
  ::decode(superblock, i);
  return 0;
}

int FileStore::update_version_stamp()
{
  return write_version_stamp();
}

int FileStore::version_stamp_is_valid(uint32_t *version)
{
  bufferptr bp(PATH_MAX);
  int ret = safe_read_file(basedir.c_str(), "store_version",
      bp.c_str(), bp.length());
  if (ret < 0) {
    return ret;
  }
  bufferlist bl;
  bl.push_back(std::move(bp));
  bufferlist::iterator i = bl.begin();
  ::decode(*version, i);
  dout(10) << __func__ << " was " << *version << " vs target "
           << target_version << dendl;
  if (*version == target_version)
    return 1;
  else
    return 0;
}

int FileStore::write_version_stamp()
{
  dout(1) << __func__ << " " << target_version << dendl;
  bufferlist bl;
  ::encode(target_version, bl);

  return safe_write_file(basedir.c_str(), "store_version",
      bl.c_str(), bl.length());
}

int FileStore::upgrade()
{
  dout(1) << "upgrade" << dendl;
  uint32_t version;
  int r = version_stamp_is_valid(&version);

  if (r == -ENOENT) {
      derr << "The store_version file doesn't exist." << dendl;
      return -EINVAL;
  }
  if (r < 0)
    return r;
  if (r == 1)
    return 0;

  if (version < 3) {
    derr << "ObjectStore is old at version " << version << ".  Please upgrade to firefly v0.80.x, convert your store, and then upgrade."  << dendl;
    return -EINVAL;
  }

  // nothing necessary in FileStore for v3 -> v4 upgrade; we just need to
  // open up DBObjectMap with the do_upgrade flag, which we already did.
  update_version_stamp();
  return 0;
}

int FileStore::read_op_seq(uint64_t *seq)
{
  int op_fd = ::open(current_op_seq_fn.c_str(), O_CREAT|O_RDWR, 0644);
  if (op_fd < 0) {
    int r = -errno;
    assert(!m_filestore_fail_eio || r != -EIO);
    return r;
  }
  char s[40];
  memset(s, 0, sizeof(s));
  int ret = safe_read(op_fd, s, sizeof(s) - 1);
  if (ret < 0) {
    derr << "error reading " << current_op_seq_fn << ": " << cpp_strerror(ret) << dendl;
    VOID_TEMP_FAILURE_RETRY(::close(op_fd));
    assert(!m_filestore_fail_eio || ret != -EIO);
    return ret;
  }
  *seq = atoll(s);
  return op_fd;
}

int FileStore::write_op_seq(int fd, uint64_t seq)
{
  char s[30];
  snprintf(s, sizeof(s), "%" PRId64 "\n", seq);
  int ret = TEMP_FAILURE_RETRY(::pwrite(fd, s, strlen(s), 0));
  if (ret < 0) {
    ret = -errno;
    assert(!m_filestore_fail_eio || ret != -EIO);
  }
  return ret;
}

int FileStore::mount()
{
  int ret;
  char buf[PATH_MAX];
  uint64_t initial_op_seq;
  uuid_d omap_fsid;
  set<string> cluster_snaps;
  CompatSet supported_compat_set = get_fs_supported_compat_set();

  dout(5) << "basedir " << basedir << " journal " << journalpath << dendl;

  ret = set_throttle_params();
  if (ret != 0)
    goto done;

  // make sure global base dir exists
  if (::access(basedir.c_str(), R_OK | W_OK)) {
    ret = -errno;
    derr << "FileStore::mount: unable to access basedir '" << basedir << "': "
         << cpp_strerror(ret) << dendl;
    goto done;
  }

  // get fsid
  snprintf(buf, sizeof(buf), "%s/fsid", basedir.c_str());
  fsid_fd = ::open(buf, O_RDWR, 0644);
  if (fsid_fd < 0) {
    ret = -errno;
    derr << "FileStore::mount: error opening '" << buf << "': "
         << cpp_strerror(ret) << dendl;
    goto done;
  }

  ret = read_fsid(fsid_fd, &fsid);
  if (ret < 0) {
    derr << "FileStore::mount: error reading fsid_fd: " << cpp_strerror(ret)
         << dendl;
    goto close_fsid_fd;
  }

  if (lock_fsid() < 0) {
    derr << "FileStore::mount: lock_fsid failed" << dendl;
    ret = -EBUSY;
    goto close_fsid_fd;
  }

  dout(10) << "mount fsid is " << fsid << dendl;


  uint32_t version_stamp;
  ret = version_stamp_is_valid(&version_stamp);
  if (ret < 0) {
    derr << "FileStore::mount: error in version_stamp_is_valid: "
         << cpp_strerror(ret) << dendl;
    goto close_fsid_fd;
  } else if (ret == 0) {
    if (do_update || (int)version_stamp < cct->_conf->filestore_update_to) {
      derr << "FileStore::mount: stale version stamp detected: "
           << version_stamp
           << ". Proceeding, do_update "
           << "is set, performing disk format upgrade."
           << dendl;
      do_update = true;
    } else {
      ret = -EINVAL;
      derr << "FileStore::mount: stale version stamp " << version_stamp
           << ". Please run the FileStore update script before starting the "
           << "OSD, or set filestore_update_to to " << target_version
           << " (currently " << cct->_conf->filestore_update_to << ")"
           << dendl;
      goto close_fsid_fd;
    }
  }

  ret = read_superblock();
  if (ret < 0) {
    goto close_fsid_fd;
  }

  // Check if this FileStore supports all the necessary features to mount
  if (supported_compat_set.compare(superblock.compat_features) == -1) {
    derr << "FileStore::mount: Incompatible features set "
           << superblock.compat_features << dendl;
    ret = -EINVAL;
    goto close_fsid_fd;
  }

  // open some dir handles
  basedir_fd = ::open(basedir.c_str(), O_RDONLY);
  if (basedir_fd < 0) {
    ret = -errno;
    derr << "FileStore::mount: failed to open " << basedir << ": "
         << cpp_strerror(ret) << dendl;
    basedir_fd = -1;
    goto close_fsid_fd;
  }

  // test for btrfs, xattrs, etc.
  ret = _detect_fs();
  if (ret < 0) {
    derr << "FileStore::mount: error in _detect_fs: "
         << cpp_strerror(ret) << dendl;
    goto close_basedir_fd;
  }

  {
    list<string> ls;
    ret = backend->list_checkpoints(ls);
    if (ret < 0) {
      derr << "FileStore::mount: error in _list_snaps: "<< cpp_strerror(ret) << dendl;
      goto close_basedir_fd;
    }

    long long unsigned c, prev = 0;
    char clustersnap[NAME_MAX];
    for (list<string>::iterator it = ls.begin(); it != ls.end(); ++it) {
      if (sscanf(it->c_str(), COMMIT_SNAP_ITEM, &c) == 1) {
        assert(c > prev);
        prev = c;
        snaps.push_back(c);
      } else if (sscanf(it->c_str(), CLUSTER_SNAP_ITEM, clustersnap) == 1)
        cluster_snaps.insert(*it);
    }
  }

  if (m_osd_rollback_to_cluster_snap.length() &&
      cluster_snaps.count(m_osd_rollback_to_cluster_snap) == 0) {
    derr << "rollback to cluster snapshot '" << m_osd_rollback_to_cluster_snap << "': not found" << dendl;
    ret = -ENOENT;
    goto close_basedir_fd;
  }

  char nosnapfn[200];
  snprintf(nosnapfn, sizeof(nosnapfn), "%s/nosnap", current_fn.c_str());

  if (backend->can_checkpoint()) {
    if (snaps.empty()) {
      dout(0) << "mount WARNING: no consistent snaps found, store may be in inconsistent state" << dendl;
    } else {
      char s[NAME_MAX];
      uint64_t curr_seq = 0;

      if (m_osd_rollback_to_cluster_snap.length()) {
        derr << TEXT_RED
             << " ** NOTE: rolling back to cluster snapshot " << m_osd_rollback_to_cluster_snap << " **"
             << TEXT_NORMAL
             << dendl;
        assert(cluster_snaps.count(m_osd_rollback_to_cluster_snap));
        snprintf(s, sizeof(s), CLUSTER_SNAP_ITEM, m_osd_rollback_to_cluster_snap.c_str());
      } else {
        {
          int fd = read_op_seq(&curr_seq);
          if (fd >= 0) {
            VOID_TEMP_FAILURE_RETRY(::close(fd));
          }
        }
        if (curr_seq)
          dout(10) << " current/ seq was " << curr_seq << dendl;
        else
          dout(10) << " current/ missing entirely (unusual, but okay)" << dendl;

        uint64_t cp = snaps.back();
        dout(10) << " most recent snap from " << snaps << " is " << cp << dendl;

        // if current/ is marked as non-snapshotted, refuse to roll
        // back (without clear direction) to avoid throwing out new
        // data.
        struct stat st;
        if (::stat(nosnapfn, &st) == 0) {
          if (!m_osd_use_stale_snap) {
            derr << "ERROR: " << nosnapfn << " exists, not rolling back to avoid losing new data" << dendl;
            derr << "Force rollback to old snapshotted version with 'osd use stale snap = true'" << dendl;
            derr << "config option for --osd-use-stale-snap startup argument." << dendl;
            ret = -ENOTSUP;
            goto close_basedir_fd;
          }
          derr << "WARNING: user forced start with data sequence mismatch: current was " << curr_seq
               << ", newest snap is " << cp << dendl;
          cerr << TEXT_YELLOW
               << " ** WARNING: forcing the use of stale snapshot data **"
               << TEXT_NORMAL << std::endl;
        }

        dout(10) << "mount rolling back to consistent snap " << cp << dendl;
        snprintf(s, sizeof(s), COMMIT_SNAP_ITEM, (long long unsigned)cp);
      }

      // drop current?
      ret = backend->rollback_to(s);
      if (ret) {
        derr << "FileStore::mount: error rolling back to " << s << ": "
             << cpp_strerror(ret) << dendl;
        goto close_basedir_fd;
      }
    }
  }
  initial_op_seq = 0;

  current_fd = ::open(current_fn.c_str(), O_RDONLY);
  if (current_fd < 0) {
    ret = -errno;
    derr << "FileStore::mount: error opening: " << current_fn << ": " << cpp_strerror(ret) << dendl;
    goto close_basedir_fd;
  }

  assert(current_fd >= 0);

  op_fd = read_op_seq(&initial_op_seq);
  if (op_fd < 0) {
    ret = op_fd;
    derr << "FileStore::mount: read_op_seq failed" << dendl;
    goto close_current_fd;
  }

  dout(5) << "mount op_seq is " << initial_op_seq << dendl;
  if (initial_op_seq == 0) {
    derr << "mount initial op seq is 0; something is wrong" << dendl;
    ret = -EINVAL;
    goto close_current_fd;
  }

  if (!backend->can_checkpoint()) {
    // mark current/ as non-snapshotted so that we don't rollback away
    // from it.
    int r = ::creat(nosnapfn, 0644);
    if (r < 0) {
      ret = -errno;
      derr << "FileStore::mount: failed to create current/nosnap" << dendl;
      goto close_current_fd;
    }
    VOID_TEMP_FAILURE_RETRY(::close(r));
  } else {
    // clear nosnap marker, if present.
    ::unlink(nosnapfn);
  }

  // check fsid with omap
  // get omap fsid
  int omap_fsid_fd;
  char omap_fsid_buf[PATH_MAX];
  struct ::stat omap_fsid_stat;
  snprintf(omap_fsid_buf, sizeof(omap_fsid_buf), "%s/osd_uuid", omap_dir.c_str());
  // if osd_uuid not exists, assume as this omap matchs corresponding osd
  if (::stat(omap_fsid_buf, &omap_fsid_stat) != 0){
    dout(10) << "Filestore::mount osd_uuid not found under omap, "
             << "assume as matched."
             << dendl;
  }else{
    // if osd_uuid exists, compares osd_uuid with fsid
    omap_fsid_fd = ::open(omap_fsid_buf, O_RDONLY, 0644);
    if (omap_fsid_fd < 0) {
        ret = -errno;
        derr << "FileStore::mount: error opening '" << omap_fsid_buf << "': "
             << cpp_strerror(ret)
             << dendl;
        goto close_current_fd;
    }
    ret = read_fsid(omap_fsid_fd, &omap_fsid);
    VOID_TEMP_FAILURE_RETRY(::close(omap_fsid_fd));
    omap_fsid_fd = -1; // defensive 
    if (ret < 0) {
      derr << "FileStore::mount: error reading omap_fsid_fd"
           << ", omap_fsid = " << omap_fsid
           << cpp_strerror(ret)
           << dendl;
      goto close_current_fd;
    }
    if (fsid != omap_fsid) {
      derr << "FileStore::mount: " << omap_fsid_buf
           << " has existed omap fsid " << omap_fsid
           << " != expected osd fsid " << fsid
           << dendl;
      ret = -EINVAL;
      goto close_current_fd;
    }
  }

  dout(0) << "start omap initiation" << dendl;
  if (!(generic_flags & SKIP_MOUNT_OMAP)) {
    KeyValueDB * omap_store = KeyValueDB::create(cct,
                                                 superblock.omap_backend,
                                                 omap_dir);
    if (omap_store == NULL)
    {
      derr << "Error creating " << superblock.omap_backend << dendl;
      ret = -1;
      goto close_current_fd;
    }

    if (superblock.omap_backend == "rocksdb")
      ret = omap_store->init(cct->_conf->filestore_rocksdb_options);
    else
      ret = omap_store->init();

    if (ret < 0) {
      derr << "Error initializing omap_store: " << cpp_strerror(ret) << dendl;
      goto close_current_fd;
    }

    stringstream err;
    if (omap_store->create_and_open(err)) {
      delete omap_store;
      derr << "Error initializing " << superblock.omap_backend
           << " : " << err.str() << dendl;
      ret = -1;
      goto close_current_fd;
    }

    DBObjectMap *dbomap = new DBObjectMap(cct, omap_store);
    ret = dbomap->init(do_update);
    if (ret < 0) {
      delete dbomap;
      derr << "Error initializing DBObjectMap: " << ret << dendl;
      goto close_current_fd;
    }
    stringstream err2;

    if (cct->_conf->filestore_debug_omap_check && !dbomap->check(err2)) {
      derr << err2.str() << dendl;
      delete dbomap;
      ret = -EINVAL;
      goto close_current_fd;
    }
    object_map.reset(dbomap);
  }

  // journal
  new_journal();

  // select journal mode?
  if (journal) {
    if (!m_filestore_journal_writeahead &&
        !m_filestore_journal_parallel &&
        !m_filestore_journal_trailing) {
      if (!backend->can_checkpoint()) {
        m_filestore_journal_writeahead = true;
        dout(0) << "mount: enabling WRITEAHEAD journal mode: checkpoint is not enabled" << dendl;
      } else {
        m_filestore_journal_parallel = true;
        dout(0) << "mount: enabling PARALLEL journal mode: fs, checkpoint is enabled" << dendl;
      }
    } else {
      if (m_filestore_journal_writeahead)
        dout(0) << "mount: WRITEAHEAD journal mode explicitly enabled in conf" << dendl;
      if (m_filestore_journal_parallel)
        dout(0) << "mount: PARALLEL journal mode explicitly enabled in conf" << dendl;
      if (m_filestore_journal_trailing)
        dout(0) << "mount: TRAILING journal mode explicitly enabled in conf" << dendl;
    }
    if (m_filestore_journal_writeahead)
      journal->set_wait_on_full(true);
  } else {
    dout(0) << "mount: no journal" << dendl;
  }

  ret = _sanity_check_fs();
  if (ret) {
    derr << "FileStore::mount: _sanity_check_fs failed with error "
         << ret << dendl;
    goto close_current_fd;
  }

  // Cleanup possibly invalid collections
  {
    vector<coll_t> collections;
    ret = list_collections(collections, true);
    if (ret < 0) {
      derr << "Error " << ret << " while listing collections" << dendl;
      goto close_current_fd;
    }
    for (vector<coll_t>::iterator i = collections.begin();
         i != collections.end();
         ++i) {
      Index index;
      ret = get_index(*i, &index);
      if (ret < 0) {
        derr << "Unable to mount index " << *i
             << " with error: " << ret << dendl;
        goto close_current_fd;
      }
      assert(NULL != index.index);
      RWLock::WLocker l((index.index)->access_lock);

      index->cleanup();
    }
  }
  if (!m_disable_wbthrottle) {
    wbthrottle.start();
  } else {
    dout(0) << "mount INFO: WbThrottle is disabled" << dendl;
    if (cct->_conf->filestore_odsync_write) {
      dout(0) << "mount INFO: O_DSYNC write is enabled" << dendl;
    }
  }
  sync_thread.create("filestore_sync");

  if (!(generic_flags & SKIP_JOURNAL_REPLAY)) {
    ret = journal_replay(initial_op_seq);
    if (ret < 0) {
      derr << "mount failed to open journal " << journalpath << ": " << cpp_strerror(ret) << dendl;
      if (ret == -ENOTTY) {
        derr << "maybe journal is not pointing to a block device and its size "
             << "wasn't configured?" << dendl;
      }

      goto stop_sync;
    }
  }

  {
    stringstream err2;
    if (cct->_conf->filestore_debug_omap_check && !object_map->check(err2)) {
      derr << err2.str() << dendl;
      ret = -EINVAL;
      goto stop_sync;
    }
  }

  init_temp_collections();

  journal_start();

  op_tp.start();
  for (vector<Finisher*>::iterator it = ondisk_finishers.begin(); it != ondisk_finishers.end(); ++it) {
    (*it)->start();
  }
  for (vector<Finisher*>::iterator it = apply_finishers.begin(); it != apply_finishers.end(); ++it) {
    (*it)->start();
  }

  timer.init();

  // upgrade?
  if (cct->_conf->filestore_update_to >= (int)get_target_version()) {
    int err = upgrade();
    if (err < 0) {
      derr << "error converting store" << dendl;
      umount();
      return err;
    }
  }

  // all okay.
  return 0;

stop_sync:
  // stop sync thread
  lock.Lock();
  stop = true;
  sync_cond.Signal();
  lock.Unlock();
  sync_thread.join();
  if (!m_disable_wbthrottle) {
    wbthrottle.stop();
  }
close_current_fd:
  VOID_TEMP_FAILURE_RETRY(::close(current_fd));
  current_fd = -1;
close_basedir_fd:
  VOID_TEMP_FAILURE_RETRY(::close(basedir_fd));
  basedir_fd = -1;
close_fsid_fd:
  VOID_TEMP_FAILURE_RETRY(::close(fsid_fd));
  fsid_fd = -1;
done:
  assert(!m_filestore_fail_eio || ret != -EIO);
  delete backend;
  backend = NULL;
  object_map.reset();
  return ret;
}

void FileStore::init_temp_collections()
{
  dout(10) << __func__ << dendl;
  vector<coll_t> ls;
  int r = list_collections(ls, true);
  assert(r >= 0);

  dout(20) << " ls " << ls << dendl;

  SequencerPosition spos;

  set<coll_t> temps;
  for (vector<coll_t>::iterator p = ls.begin(); p != ls.end(); ++p)
    if (p->is_temp())
      temps.insert(*p);
  dout(20) << " temps " << temps << dendl;

  for (vector<coll_t>::iterator p = ls.begin(); p != ls.end(); ++p) {
    if (p->is_temp())
      continue;
    if (p->is_meta())
      continue;
    coll_t temp = p->get_temp();
    if (temps.count(temp)) {
      temps.erase(temp);
    } else {
      dout(10) << __func__ << " creating " << temp << dendl;
      r = _create_collection(temp, 0, spos);
      assert(r == 0);
    }
  }

  for (set<coll_t>::iterator p = temps.begin(); p != temps.end(); ++p) {
    dout(10) << __func__ << " removing stray " << *p << dendl;
    r = _collection_remove_recursive(*p, spos);
    assert(r == 0);
  }
}

int FileStore::umount()
{
  dout(5) << "umount " << basedir << dendl;

  flush();
  sync();
  do_force_sync();

  lock.Lock();
  stop = true;
  sync_cond.Signal();
  lock.Unlock();
  sync_thread.join();
  if (!m_disable_wbthrottle){
    wbthrottle.stop();
  }
  op_tp.stop();

  journal_stop();
  if (!(generic_flags & SKIP_JOURNAL_REPLAY))
    journal_write_close();

  for (vector<Finisher*>::iterator it = ondisk_finishers.begin(); it != ondisk_finishers.end(); ++it) {
    (*it)->stop();
  }
  for (vector<Finisher*>::iterator it = apply_finishers.begin(); it != apply_finishers.end(); ++it) {
    (*it)->stop();
  }

  if (fsid_fd >= 0) {
    VOID_TEMP_FAILURE_RETRY(::close(fsid_fd));
    fsid_fd = -1;
  }
  if (op_fd >= 0) {
    VOID_TEMP_FAILURE_RETRY(::close(op_fd));
    op_fd = -1;
  }
  if (current_fd >= 0) {
    VOID_TEMP_FAILURE_RETRY(::close(current_fd));
    current_fd = -1;
  }
  if (basedir_fd >= 0) {
    VOID_TEMP_FAILURE_RETRY(::close(basedir_fd));
    basedir_fd = -1;
  }

  force_sync = false;

  delete backend;
  backend = NULL;

  object_map.reset();

  {
    Mutex::Locker l(sync_entry_timeo_lock);
    timer.shutdown();
  }

  // nothing
  return 0;
}




/// -----------------------------

FileStore::Op *FileStore::build_op(vector<Transaction>& tls,
                                   Context *onreadable,
                                   Context *onreadable_sync,
                                   TrackedOpRef osd_op)
{
  uint64_t bytes = 0, ops = 0;
  for (vector<Transaction>::iterator p = tls.begin();
       p != tls.end();
       ++p) {
    bytes += (*p).get_num_bytes();
    ops += (*p).get_num_ops();
  }

  Op *o = new Op;
  o->start = ceph_clock_now();
  o->tls = std::move(tls);
  o->onreadable = onreadable;
  o->onreadable_sync = onreadable_sync;
  o->ops = ops;
  o->bytes = bytes;
  o->osd_op = osd_op;
  return o;
}



void FileStore::queue_op(OpSequencer *osr, Op *o)
{
  // queue op on sequencer, then queue sequencer for the threadpool,
  // so that regardless of which order the threads pick up the
  // sequencer, the op order will be preserved.

  osr->queue(o);
  o->trace.event("queued");

  logger->inc(l_filestore_ops);
  logger->inc(l_filestore_bytes, o->bytes);

  dout(5) << "queue_op " << o << " seq " << o->op
          << " " << *osr
          << " " << o->bytes << " bytes"
          << "   (queue has " << throttle_ops.get_current() << " ops and " << throttle_bytes.get_current() << " bytes)"
          << dendl;
  op_wq.queue(osr);
}

void FileStore::op_queue_reserve_throttle(Op *o)
{
  throttle_ops.get();
  throttle_bytes.get(o->bytes);

  logger->set(l_filestore_op_queue_ops, throttle_ops.get_current());
  logger->set(l_filestore_op_queue_bytes, throttle_bytes.get_current());
}

void FileStore::op_queue_release_throttle(Op *o)
{
  throttle_ops.put();
  throttle_bytes.put(o->bytes);
  logger->set(l_filestore_op_queue_ops, throttle_ops.get_current());
  logger->set(l_filestore_op_queue_bytes, throttle_bytes.get_current());
}

void FileStore::_do_op(OpSequencer *osr, ThreadPool::TPHandle &handle)
{
  if (!m_disable_wbthrottle) {
    wbthrottle.throttle();
  }
  // inject a stall?
  if (cct->_conf->filestore_inject_stall) {
    int orig = cct->_conf->filestore_inject_stall;
    dout(5) << "_do_op filestore_inject_stall " << orig << ", sleeping" << dendl;
    sleep(orig);
    cct->_conf->set_val("filestore_inject_stall", "0");
    dout(5) << "_do_op done stalling" << dendl;
  }

  osr->apply_lock.Lock();
  Op *o = osr->peek_queue();
  o->trace.event("op_apply_start");
  apply_manager.op_apply_start(o->op);
  dout(5) << "_do_op " << o << " seq " << o->op << " " << *osr << "/" << osr->parent << " start" << dendl;
  o->trace.event("_do_transactions start");
  int r = _do_transactions(o->tls, o->op, &handle);
  o->trace.event("op_apply_finish");
  apply_manager.op_apply_finish(o->op);
  dout(10) << "_do_op " << o << " seq " << o->op << " r = " << r
           << ", finisher " << o->onreadable << " " << o->onreadable_sync << dendl;

  o->tls.clear();

}

void FileStore::_finish_op(OpSequencer *osr)
{
  list<Context*> to_queue;
  Op *o = osr->dequeue(&to_queue);

  utime_t lat = ceph_clock_now();
  lat -= o->start;

  dout(10) << "_finish_op " << o << " seq " << o->op << " " << *osr << "/" << osr->parent << " lat " << lat << dendl;
  osr->apply_lock.Unlock();  // locked in _do_op
  o->trace.event("_finish_op");

  // called with tp lock held
  op_queue_release_throttle(o);

  logger->tinc(l_filestore_apply_latency, lat);

  if (o->onreadable_sync) {
    o->onreadable_sync->complete(0);
  }
  if (o->onreadable) {
    apply_finishers[osr->id % m_apply_finisher_num]->queue(o->onreadable);
  }
  if (!to_queue.empty()) {
    apply_finishers[osr->id % m_apply_finisher_num]->queue(to_queue);
  }
  delete o;
}


struct C_JournaledAhead : public Context {
  FileStore *fs;
  FileStore::OpSequencer *osr;
  FileStore::Op *o;
  Context *ondisk;

  C_JournaledAhead(FileStore *f, FileStore::OpSequencer *os, FileStore::Op *o, Context *ondisk):
    fs(f), osr(os), o(o), ondisk(ondisk) { }
  void finish(int r) override {
    fs->_journaled_ahead(osr, o, ondisk);
  }
};

int FileStore::queue_transactions(Sequencer *posr, vector<Transaction>& tls,
                                  TrackedOpRef osd_op,
                                  ThreadPool::TPHandle *handle)
{
  Context *onreadable;
  Context *ondisk;
  Context *onreadable_sync;
  ObjectStore::Transaction::collect_contexts(
    tls, &onreadable, &ondisk, &onreadable_sync);

  if (cct->_conf->objectstore_blackhole) {
    dout(0) << __func__ << " objectstore_blackhole = TRUE, dropping transaction"
            << dendl;
    delete ondisk;
    delete onreadable;
    delete onreadable_sync;
    return 0;
  }

  utime_t start = ceph_clock_now();
  // set up the sequencer
  OpSequencer *osr;
  assert(posr);
  if (posr->p) {
    osr = static_cast<OpSequencer *>(posr->p.get());
    dout(5) << "queue_transactions existing " << osr << " " << *osr << dendl;
  } else {
    osr = new OpSequencer(cct, next_osr_id.inc());
    osr->set_cct(cct);
    osr->parent = posr;
    posr->p = osr;
    dout(5) << "queue_transactions new " << osr << " " << *osr << dendl;
  }

  // used to include osr information in tracepoints during transaction apply
  for (vector<Transaction>::iterator i = tls.begin(); i != tls.end(); ++i) {
    (*i).set_osr(osr);
  }

  ZTracer::Trace trace;
  if (osd_op && osd_op->pg_trace) {
    osd_op->store_trace.init("filestore op", &trace_endpoint, &osd_op->pg_trace);
    trace = osd_op->store_trace;
  }

  if (journal && journal->is_writeable() && !m_filestore_journal_trailing) {
    Op *o = build_op(tls, onreadable, onreadable_sync, osd_op);

    //prepare and encode transactions data out of lock
    bufferlist tbl;
    int orig_len = journal->prepare_entry(o->tls, &tbl);

    if (handle)
      handle->suspend_tp_timeout();

    op_queue_reserve_throttle(o);
    journal->reserve_throttle_and_backoff(tbl.length());

    if (handle)
      handle->reset_tp_timeout();

    uint64_t op_num = submit_manager.op_submit_start();
    o->op = op_num;
    trace.keyval("opnum", op_num);

    if (m_filestore_do_dump)
      dump_transactions(o->tls, o->op, osr);

    if (m_filestore_journal_parallel) {
      dout(5) << "queue_transactions (parallel) " << o->op << " " << o->tls << dendl;

      trace.keyval("journal mode", "parallel");
      trace.event("journal started");
      _op_journal_transactions(tbl, orig_len, o->op, ondisk, osd_op);

      // queue inside submit_manager op submission lock
      queue_op(osr, o);
      trace.event("op queued");
    } else if (m_filestore_journal_writeahead) {
      dout(5) << "queue_transactions (writeahead) " << o->op << " " << o->tls << dendl;

      osr->queue_journal(o->op);

      trace.keyval("journal mode", "writeahead");
      trace.event("journal started");
      _op_journal_transactions(tbl, orig_len, o->op,
                               new C_JournaledAhead(this, osr, o, ondisk),
                               osd_op);
    } else {
      ceph_abort();
    }
    submit_manager.op_submit_finish(op_num);
    utime_t end = ceph_clock_now();
    logger->tinc(l_filestore_queue_transaction_latency_avg, end - start);
    return 0;
  }

  if (!journal) {
    Op *o = build_op(tls, onreadable, onreadable_sync, osd_op);
    dout(5) << __func__ << " (no journal) " << o << " " << tls << dendl;

    if (handle)
      handle->suspend_tp_timeout();

    op_queue_reserve_throttle(o);

    if (handle)
      handle->reset_tp_timeout();

    uint64_t op_num = submit_manager.op_submit_start();
    o->op = op_num;

    if (m_filestore_do_dump)
      dump_transactions(o->tls, o->op, osr);

    queue_op(osr, o);
    trace.keyval("opnum", op_num);
    trace.keyval("journal mode", "none");
    trace.event("op queued");

    if (ondisk)
      apply_manager.add_waiter(op_num, ondisk);
    submit_manager.op_submit_finish(op_num);
    utime_t end = ceph_clock_now();
    logger->tinc(l_filestore_queue_transaction_latency_avg, end - start);
    return 0;
  }

  assert(journal);
  //prepare and encode transactions data out of lock
  bufferlist tbl;
  int orig_len = -1;
  if (journal->is_writeable()) {
    orig_len = journal->prepare_entry(tls, &tbl);
  }
  uint64_t op = submit_manager.op_submit_start();
  dout(5) << "queue_transactions (trailing journal) " << op << " " << tls << dendl;

  if (m_filestore_do_dump)
    dump_transactions(tls, op, osr);

  trace.event("op_apply_start");
  trace.keyval("opnum", op);
  trace.keyval("journal mode", "trailing");
  apply_manager.op_apply_start(op);
  trace.event("do_transactions");
  int r = do_transactions(tls, op);

  if (r >= 0) {
    trace.event("journal started");
    _op_journal_transactions(tbl, orig_len, op, ondisk, osd_op);
  } else {
    delete ondisk;
  }

  // start on_readable finisher after we queue journal item, as on_readable callback
  // is allowed to delete the Transaction
  if (onreadable_sync) {
    onreadable_sync->complete(r);
  }
  apply_finishers[osr->id % m_apply_finisher_num]->queue(onreadable, r);

  submit_manager.op_submit_finish(op);
  trace.event("op_apply_finish");
  apply_manager.op_apply_finish(op);

  utime_t end = ceph_clock_now();
  logger->tinc(l_filestore_queue_transaction_latency_avg, end - start);
  return r;
}

void FileStore::_journaled_ahead(OpSequencer *osr, Op *o, Context *ondisk)
{
  dout(5) << "_journaled_ahead " << o << " seq " << o->op << " " << *osr << " " << o->tls << dendl;

  o->trace.event("writeahead journal finished");

  // this should queue in order because the journal does it's completions in order.
  queue_op(osr, o);

  list<Context*> to_queue;
  osr->dequeue_journal(&to_queue);

  // do ondisk completions async, to prevent any onreadable_sync completions
  // getting blocked behind an ondisk completion.
  if (ondisk) {
    dout(10) << " queueing ondisk " << ondisk << dendl;
    ondisk_finishers[osr->id % m_ondisk_finisher_num]->queue(ondisk);
  }
  if (!to_queue.empty()) {
    ondisk_finishers[osr->id % m_ondisk_finisher_num]->queue(to_queue);
  }
}

int FileStore::_do_transactions(
  vector<Transaction> &tls,
  uint64_t op_seq,
  ThreadPool::TPHandle *handle)
{
  int trans_num = 0;

  for (vector<Transaction>::iterator p = tls.begin();
       p != tls.end();
       ++p, trans_num++) {
    _do_transaction(*p, op_seq, trans_num, handle);
    if (handle)
      handle->reset_tp_timeout();
  }

  return 0;
}

void FileStore::_set_global_replay_guard(const coll_t& cid,
                                         const SequencerPosition &spos)
{
  if (backend->can_checkpoint())
    return;

  // sync all previous operations on this sequencer
  int ret = object_map->sync();
  if (ret < 0) {
    derr << __func__ << " : omap sync error " << cpp_strerror(ret) << dendl;
    assert(0 == "_set_global_replay_guard failed");
  }
  ret = sync_filesystem(basedir_fd);
  if (ret < 0) {
    derr << __func__ << " : sync_filesystem error " << cpp_strerror(ret) << dendl;
    assert(0 == "_set_global_replay_guard failed");
  }

  char fn[PATH_MAX];
  get_cdir(cid, fn, sizeof(fn));
  int fd = ::open(fn, O_RDONLY);
  if (fd < 0) {
    int err = errno;
    derr << __func__ << ": " << cid << " error " << cpp_strerror(err) << dendl;
    assert(0 == "_set_global_replay_guard failed");
  }

  _inject_failure();

  // then record that we did it
  bufferlist v;
  ::encode(spos, v);
  int r = chain_fsetxattr<true, true>(
    fd, GLOBAL_REPLAY_GUARD_XATTR, v.c_str(), v.length());
  if (r < 0) {
    derr << __func__ << ": fsetxattr " << GLOBAL_REPLAY_GUARD_XATTR
         << " got " << cpp_strerror(r) << dendl;
    assert(0 == "fsetxattr failed");
  }

  // and make sure our xattr is durable.
  ::fsync(fd);

  _inject_failure();

  VOID_TEMP_FAILURE_RETRY(::close(fd));
  dout(10) << __func__ << ": " << spos << " done" << dendl;
}

int FileStore::_check_global_replay_guard(const coll_t& cid,
                                          const SequencerPosition& spos)
{
  char fn[PATH_MAX];
  get_cdir(cid, fn, sizeof(fn));
  int fd = ::open(fn, O_RDONLY);
  if (fd < 0) {
    dout(10) << __func__ << ": " << cid << " dne" << dendl;
    return 1;  // if collection does not exist, there is no guard, and we can replay.
  }

  char buf[100];
  int r = chain_fgetxattr(fd, GLOBAL_REPLAY_GUARD_XATTR, buf, sizeof(buf));
  if (r < 0) {
    dout(20) << __func__ << " no xattr" << dendl;
    assert(!m_filestore_fail_eio || r != -EIO);
    VOID_TEMP_FAILURE_RETRY(::close(fd));
    return 1;  // no xattr
  }
  bufferlist bl;
  bl.append(buf, r);

  SequencerPosition opos;
  bufferlist::iterator p = bl.begin();
  ::decode(opos, p);

  VOID_TEMP_FAILURE_RETRY(::close(fd));
  return spos >= opos ? 1 : -1;
}


void FileStore::_set_replay_guard(const coll_t& cid,
                                  const SequencerPosition &spos,
                                  bool in_progress=false)
{
  char fn[PATH_MAX];
  get_cdir(cid, fn, sizeof(fn));
  int fd = ::open(fn, O_RDONLY);
  if (fd < 0) {
    int err = errno;
    derr << "_set_replay_guard " << cid << " error " << cpp_strerror(err) << dendl;
    assert(0 == "_set_replay_guard failed");
  }
  _set_replay_guard(fd, spos, 0, in_progress);
  VOID_TEMP_FAILURE_RETRY(::close(fd));
}


void FileStore::_set_replay_guard(int fd,
                                  const SequencerPosition& spos,
                                  const ghobject_t *hoid,
                                  bool in_progress)
{
  if (backend->can_checkpoint())
    return;

  dout(10) << "_set_replay_guard " << spos << (in_progress ? " START" : "") << dendl;

  _inject_failure();

  // first make sure the previous operation commits
  ::fsync(fd);

  if (!in_progress) {
    // sync object_map too.  even if this object has a header or keys,
    // it have had them in the past and then removed them, so always
    // sync.
    object_map->sync(hoid, &spos);
  }

  _inject_failure();

  // then record that we did it
  bufferlist v(40);
  ::encode(spos, v);
  ::encode(in_progress, v);
  int r = chain_fsetxattr<true, true>(
    fd, REPLAY_GUARD_XATTR, v.c_str(), v.length());
  if (r < 0) {
    derr << "fsetxattr " << REPLAY_GUARD_XATTR << " got " << cpp_strerror(r) << dendl;
    assert(0 == "fsetxattr failed");
  }

  // and make sure our xattr is durable.
  ::fsync(fd);

  _inject_failure();

  dout(10) << "_set_replay_guard " << spos << " done" << dendl;
}

void FileStore::_close_replay_guard(const coll_t& cid,
                                    const SequencerPosition &spos)
{
  char fn[PATH_MAX];
  get_cdir(cid, fn, sizeof(fn));
  int fd = ::open(fn, O_RDONLY);
  if (fd < 0) {
    int err = errno;
    derr << "_close_replay_guard " << cid << " error " << cpp_strerror(err) << dendl;
    assert(0 == "_close_replay_guard failed");
  }
  _close_replay_guard(fd, spos);
  VOID_TEMP_FAILURE_RETRY(::close(fd));
}

void FileStore::_close_replay_guard(int fd, const SequencerPosition& spos,
                                    const ghobject_t *hoid)
{
  if (backend->can_checkpoint())
    return;

  dout(10) << "_close_replay_guard " << spos << dendl;

  _inject_failure();

  // sync object_map too.  even if this object has a header or keys,
  // it have had them in the past and then removed them, so always
  // sync.
  object_map->sync(hoid, &spos);

  // then record that we are done with this operation
  bufferlist v(40);
  ::encode(spos, v);
  bool in_progress = false;
  ::encode(in_progress, v);
  int r = chain_fsetxattr<true, true>(
    fd, REPLAY_GUARD_XATTR, v.c_str(), v.length());
  if (r < 0) {
    derr << "fsetxattr " << REPLAY_GUARD_XATTR << " got " << cpp_strerror(r) << dendl;
    assert(0 == "fsetxattr failed");
  }

  // and make sure our xattr is durable.
  ::fsync(fd);

  _inject_failure();

  dout(10) << "_close_replay_guard " << spos << " done" << dendl;
}

int FileStore::_check_replay_guard(const coll_t& cid, const ghobject_t &oid,
                                   const SequencerPosition& spos)
{
  if (!replaying || backend->can_checkpoint())
    return 1;

  int r = _check_global_replay_guard(cid, spos);
  if (r < 0)
    return r;

  FDRef fd;
  r = lfn_open(cid, oid, false, &fd);
  if (r < 0) {
    dout(10) << "_check_replay_guard " << cid << " " << oid << " dne" << dendl;
    return 1;  // if file does not exist, there is no guard, and we can replay.
  }
  int ret = _check_replay_guard(**fd, spos);
  lfn_close(fd);
  return ret;
}

int FileStore::_check_replay_guard(const coll_t& cid, const SequencerPosition& spos)
{
  if (!replaying || backend->can_checkpoint())
    return 1;

  char fn[PATH_MAX];
  get_cdir(cid, fn, sizeof(fn));
  int fd = ::open(fn, O_RDONLY);
  if (fd < 0) {
    dout(10) << "_check_replay_guard " << cid << " dne" << dendl;
    return 1;  // if collection does not exist, there is no guard, and we can replay.
  }
  int ret = _check_replay_guard(fd, spos);
  VOID_TEMP_FAILURE_RETRY(::close(fd));
  return ret;
}

int FileStore::_check_replay_guard(int fd, const SequencerPosition& spos)
{
  if (!replaying || backend->can_checkpoint())
    return 1;

  char buf[100];
  int r = chain_fgetxattr(fd, REPLAY_GUARD_XATTR, buf, sizeof(buf));
  if (r < 0) {
    dout(20) << "_check_replay_guard no xattr" << dendl;
    assert(!m_filestore_fail_eio || r != -EIO);
    return 1;  // no xattr
  }
  bufferlist bl;
  bl.append(buf, r);

  SequencerPosition opos;
  bufferlist::iterator p = bl.begin();
  ::decode(opos, p);
  bool in_progress = false;
  if (!p.end())   // older journals don't have this
    ::decode(in_progress, p);
  if (opos > spos) {
    dout(10) << "_check_replay_guard object has " << opos << " > current pos " << spos
             << ", now or in future, SKIPPING REPLAY" << dendl;
    return -1;
  } else if (opos == spos) {
    if (in_progress) {
      dout(10) << "_check_replay_guard object has " << opos << " == current pos " << spos
               << ", in_progress=true, CONDITIONAL REPLAY" << dendl;
      return 0;
    } else {
      dout(10) << "_check_replay_guard object has " << opos << " == current pos " << spos
               << ", in_progress=false, SKIPPING REPLAY" << dendl;
      return -1;
    }
  } else {
    dout(10) << "_check_replay_guard object has " << opos << " < current pos " << spos
             << ", in past, will replay" << dendl;
    return 1;
  }
}

void FileStore::_do_transaction(
  Transaction& t, uint64_t op_seq, int trans_num,
  ThreadPool::TPHandle *handle)
{
  dout(10) << "_do_transaction on " << &t << dendl;

#ifdef WITH_LTTNG
  const char *osr_name = t.get_osr() ? static_cast<OpSequencer*>(t.get_osr())->get_name().c_str() : "<NULL>";
#endif

  Transaction::iterator i = t.begin();

  SequencerPosition spos(op_seq, trans_num, 0);
  while (i.have_op()) {
    if (handle)
      handle->reset_tp_timeout();

    Transaction::Op *op = i.decode_op();
    int r = 0;

    _inject_failure();

    switch (op->op) {
    case Transaction::OP_NOP:
      break;
    case Transaction::OP_TOUCH:
      {
        const coll_t &_cid = i.get_cid(op->cid);
        const ghobject_t &oid = i.get_oid(op->oid);
        const coll_t &cid = !_need_temp_object_collection(_cid, oid) ?
          _cid : _cid.get_temp();
        tracepoint(objectstore, touch_enter, osr_name);
        if (_check_replay_guard(cid, oid, spos) > 0)
          r = _touch(cid, oid);
        tracepoint(objectstore, touch_exit, r);
      }
      break;

    case Transaction::OP_WRITE:
      {
        const coll_t &_cid = i.get_cid(op->cid);
        const ghobject_t &oid = i.get_oid(op->oid);
        const coll_t &cid = !_need_temp_object_collection(_cid, oid) ?
          _cid : _cid.get_temp();
        uint64_t off = op->off;
        uint64_t len = op->len;
        uint32_t fadvise_flags = i.get_fadvise_flags();
        bufferlist bl;
        i.decode_bl(bl);
        tracepoint(objectstore, write_enter, osr_name, off, len);
        if (_check_replay_guard(cid, oid, spos) > 0)
          r = _write(cid, oid, off, len, bl, fadvise_flags);
        tracepoint(objectstore, write_exit, r);
      }
      break;

    case Transaction::OP_ZERO:
      {
        const coll_t &_cid = i.get_cid(op->cid);
        const ghobject_t &oid = i.get_oid(op->oid);
        const coll_t &cid = !_need_temp_object_collection(_cid, oid) ?
          _cid : _cid.get_temp();
        uint64_t off = op->off;
        uint64_t len = op->len;
        tracepoint(objectstore, zero_enter, osr_name, off, len);
        if (_check_replay_guard(cid, oid, spos) > 0)
          r = _zero(cid, oid, off, len);
        tracepoint(objectstore, zero_exit, r);
      }
      break;

    case Transaction::OP_TRIMCACHE:
      {
        // deprecated, no-op
      }
      break;

    case Transaction::OP_TRUNCATE:
      {
        const coll_t &_cid = i.get_cid(op->cid);
        const ghobject_t &oid = i.get_oid(op->oid);
        const coll_t &cid = !_need_temp_object_collection(_cid, oid) ?
          _cid : _cid.get_temp();
        uint64_t off = op->off;
        tracepoint(objectstore, truncate_enter, osr_name, off);
        if (_check_replay_guard(cid, oid, spos) > 0)
          r = _truncate(cid, oid, off);
        tracepoint(objectstore, truncate_exit, r);
      }
      break;

    case Transaction::OP_REMOVE:
      {
        const coll_t &_cid = i.get_cid(op->cid);
        const ghobject_t &oid = i.get_oid(op->oid);
        const coll_t &cid = !_need_temp_object_collection(_cid, oid) ?
          _cid : _cid.get_temp();
        tracepoint(objectstore, remove_enter, osr_name);
        if (_check_replay_guard(cid, oid, spos) > 0)
          r = _remove(cid, oid, spos);
        tracepoint(objectstore, remove_exit, r);
      }
      break;

    case Transaction::OP_SETATTR:
      {
        const coll_t &_cid = i.get_cid(op->cid);
        const ghobject_t &oid = i.get_oid(op->oid);
        const coll_t &cid = !_need_temp_object_collection(_cid, oid) ?
          _cid : _cid.get_temp();
        string name = i.decode_string();
        bufferlist bl;
        i.decode_bl(bl);
        tracepoint(objectstore, setattr_enter, osr_name);
        if (_check_replay_guard(cid, oid, spos) > 0) {
          map<string, bufferptr> to_set;
          to_set[name] = bufferptr(bl.c_str(), bl.length());
          r = _setattrs(cid, oid, to_set, spos);
          if (r == -ENOSPC)
            dout(0) << " ENOSPC on setxattr on " << cid << "/" << oid
                    << " name " << name << " size " << bl.length() << dendl;
        }
        tracepoint(objectstore, setattr_exit, r);
      }
      break;

    case Transaction::OP_SETATTRS:
      {
        const coll_t &_cid = i.get_cid(op->cid);
        const ghobject_t &oid = i.get_oid(op->oid);
        const coll_t &cid = !_need_temp_object_collection(_cid, oid) ?
          _cid : _cid.get_temp();
        map<string, bufferptr> aset;
        i.decode_attrset(aset);
        tracepoint(objectstore, setattrs_enter, osr_name);
        if (_check_replay_guard(cid, oid, spos) > 0)
          r = _setattrs(cid, oid, aset, spos);
        tracepoint(objectstore, setattrs_exit, r);
        if (r == -ENOSPC)
          dout(0) << " ENOSPC on setxattrs on " << cid << "/" << oid << dendl;
      }
      break;

    case Transaction::OP_RMATTR:
      {
        const coll_t &_cid = i.get_cid(op->cid);
        const ghobject_t &oid = i.get_oid(op->oid);
        const coll_t &cid = !_need_temp_object_collection(_cid, oid) ?
          _cid : _cid.get_temp();
        string name = i.decode_string();
        tracepoint(objectstore, rmattr_enter, osr_name);
        if (_check_replay_guard(cid, oid, spos) > 0)
          r = _rmattr(cid, oid, name.c_str(), spos);
        tracepoint(objectstore, rmattr_exit, r);
      }
      break;

    case Transaction::OP_RMATTRS:
      {
        const coll_t &_cid = i.get_cid(op->cid);
        const ghobject_t &oid = i.get_oid(op->oid);
        const coll_t &cid = !_need_temp_object_collection(_cid, oid) ?
          _cid : _cid.get_temp();
        tracepoint(objectstore, rmattrs_enter, osr_name);
        if (_check_replay_guard(cid, oid, spos) > 0)
          r = _rmattrs(cid, oid, spos);
        tracepoint(objectstore, rmattrs_exit, r);
      }
      break;

    case Transaction::OP_CLONE:
      {
        const coll_t &_cid = i.get_cid(op->cid);
        const ghobject_t &oid = i.get_oid(op->oid);
        const coll_t &cid = !_need_temp_object_collection(_cid, oid) ?
          _cid : _cid.get_temp();
        const ghobject_t &noid = i.get_oid(op->dest_oid);
        tracepoint(objectstore, clone_enter, osr_name);
        r = _clone(cid, oid, noid, spos);
        tracepoint(objectstore, clone_exit, r);
      }
      break;

    case Transaction::OP_CLONERANGE:
      {
        const coll_t &_cid = i.get_cid(op->cid);
        const ghobject_t &oid = i.get_oid(op->oid);
        const ghobject_t &noid = i.get_oid(op->dest_oid);
        const coll_t &cid = !_need_temp_object_collection(_cid, oid) ?
          _cid : _cid.get_temp();
        const coll_t &ncid = !_need_temp_object_collection(_cid, noid) ?
          _cid : _cid.get_temp();
        uint64_t off = op->off;
        uint64_t len = op->len;
        tracepoint(objectstore, clone_range_enter, osr_name, len);
        r = _clone_range(cid, oid, ncid, noid, off, len, off, spos);
        tracepoint(objectstore, clone_range_exit, r);
      }
      break;

    case Transaction::OP_CLONERANGE2:
      {
        const coll_t &_cid = i.get_cid(op->cid);
        const ghobject_t &oid = i.get_oid(op->oid);
        const ghobject_t &noid = i.get_oid(op->dest_oid);
        const coll_t &cid = !_need_temp_object_collection(_cid, oid) ?
          _cid : _cid.get_temp();
        const coll_t &ncid = !_need_temp_object_collection(_cid, noid) ?
          _cid : _cid.get_temp();
        uint64_t srcoff = op->off;
        uint64_t len = op->len;
        uint64_t dstoff = op->dest_off;
        tracepoint(objectstore, clone_range2_enter, osr_name, len);
        r = _clone_range(cid, oid, ncid, noid, srcoff, len, dstoff, spos);
        tracepoint(objectstore, clone_range2_exit, r);
      }
      break;

    case Transaction::OP_MKCOLL:
      {
        const coll_t &cid = i.get_cid(op->cid);
        tracepoint(objectstore, mkcoll_enter, osr_name);
        if (_check_replay_guard(cid, spos) > 0)
          r = _create_collection(cid, op->split_bits, spos);
        tracepoint(objectstore, mkcoll_exit, r);
      }
      break;

    case Transaction::OP_COLL_SET_BITS:
      {
        const coll_t &cid = i.get_cid(op->cid);
        int bits = op->split_bits;
        r = _collection_set_bits(cid, bits);
      }
      break;

    case Transaction::OP_COLL_HINT:
      {
        const coll_t &cid = i.get_cid(op->cid);
        uint32_t type = op->hint_type;
        bufferlist hint;
        i.decode_bl(hint);
        bufferlist::iterator hiter = hint.begin();
        if (type == Transaction::COLL_HINT_EXPECTED_NUM_OBJECTS) {
          uint32_t pg_num;
          uint64_t num_objs;
          ::decode(pg_num, hiter);
          ::decode(num_objs, hiter);
          if (_check_replay_guard(cid, spos) > 0) {
            r = _collection_hint_expected_num_objs(cid, pg_num, num_objs, spos);
          }
        } else {
          // Ignore the hint
          dout(10) << "Unrecognized collection hint type: " << type << dendl;
        }
      }
      break;

    case Transaction::OP_RMCOLL:
      {
        const coll_t &cid = i.get_cid(op->cid);
        tracepoint(objectstore, rmcoll_enter, osr_name);
        if (_check_replay_guard(cid, spos) > 0)
          r = _destroy_collection(cid);
        tracepoint(objectstore, rmcoll_exit, r);
      }
      break;

    case Transaction::OP_COLL_ADD:
      {
        const coll_t &ocid = i.get_cid(op->cid);
        const coll_t &ncid = i.get_cid(op->dest_cid);
        const ghobject_t &oid = i.get_oid(op->oid);

        assert(oid.hobj.pool >= -1);

        // always followed by OP_COLL_REMOVE
        Transaction::Op *op2 = i.decode_op();
        const coll_t &ocid2 = i.get_cid(op2->cid);
        const ghobject_t &oid2 = i.get_oid(op2->oid);
        assert(op2->op == Transaction::OP_COLL_REMOVE);
        assert(ocid2 == ocid);
        assert(oid2 == oid);

        tracepoint(objectstore, coll_add_enter);
        r = _collection_add(ncid, ocid, oid, spos);
        tracepoint(objectstore, coll_add_exit, r);
        spos.op++;
        if (r < 0)
          break;
        tracepoint(objectstore, coll_remove_enter, osr_name);
        if (_check_replay_guard(ocid, oid, spos) > 0)
          r = _remove(ocid, oid, spos);
        tracepoint(objectstore, coll_remove_exit, r);
      }
      break;

    case Transaction::OP_COLL_MOVE:
      {
        // WARNING: this is deprecated and buggy; only here to replay old journals.
        const coll_t &ocid = i.get_cid(op->cid);
        const coll_t &ncid = i.get_cid(op->dest_cid);
        const ghobject_t &oid = i.get_oid(op->oid);
        tracepoint(objectstore, coll_move_enter);
        r = _collection_add(ocid, ncid, oid, spos);
        if (r == 0 &&
            (_check_replay_guard(ocid, oid, spos) > 0))
          r = _remove(ocid, oid, spos);
        tracepoint(objectstore, coll_move_exit, r);
      }
      break;

    case Transaction::OP_COLL_MOVE_RENAME:
      {
        const coll_t &_oldcid = i.get_cid(op->cid);
        const ghobject_t &oldoid = i.get_oid(op->oid);
        const coll_t &_newcid = i.get_cid(op->dest_cid);
        const ghobject_t &newoid = i.get_oid(op->dest_oid);
        const coll_t &oldcid = !_need_temp_object_collection(_oldcid, oldoid) ?
          _oldcid : _oldcid.get_temp();
        const coll_t &newcid = !_need_temp_object_collection(_newcid, newoid) ?
          _oldcid : _newcid.get_temp();
        tracepoint(objectstore, coll_move_rename_enter);
        r = _collection_move_rename(oldcid, oldoid, newcid, newoid, spos);
        tracepoint(objectstore, coll_move_rename_exit, r);
      }
      break;

    case Transaction::OP_TRY_RENAME:
      {
        const coll_t &_cid = i.get_cid(op->cid);
        const ghobject_t &oldoid = i.get_oid(op->oid);
        const ghobject_t &newoid = i.get_oid(op->dest_oid);
        const coll_t &oldcid = !_need_temp_object_collection(_cid, oldoid) ?
          _cid : _cid.get_temp();
        const coll_t &newcid = !_need_temp_object_collection(_cid, newoid) ?
          _cid : _cid.get_temp();
        tracepoint(objectstore, coll_try_rename_enter);
        r = _collection_move_rename(oldcid, oldoid, newcid, newoid, spos, true);
        tracepoint(objectstore, coll_try_rename_exit, r);
      }
      break;

    case Transaction::OP_COLL_SETATTR:
    case Transaction::OP_COLL_RMATTR:
      assert(0 == "collection attr methods no longer implemented");
      break;

    case Transaction::OP_STARTSYNC:
      tracepoint(objectstore, startsync_enter, osr_name);
      _start_sync();
      tracepoint(objectstore, startsync_exit);
      break;

    case Transaction::OP_COLL_RENAME:
      {
        r = -EOPNOTSUPP;
      }
      break;

    case Transaction::OP_OMAP_CLEAR:
      {
        const coll_t &_cid = i.get_cid(op->cid);
        const ghobject_t &oid = i.get_oid(op->oid);
        const coll_t &cid = !_need_temp_object_collection(_cid, oid) ?
          _cid : _cid.get_temp();
        tracepoint(objectstore, omap_clear_enter, osr_name);
        r = _omap_clear(cid, oid, spos);
        tracepoint(objectstore, omap_clear_exit, r);
      }
      break;
    case Transaction::OP_OMAP_SETKEYS:
      {
        const coll_t &_cid = i.get_cid(op->cid);
        const ghobject_t &oid = i.get_oid(op->oid);
        const coll_t &cid = !_need_temp_object_collection(_cid, oid) ?
          _cid : _cid.get_temp();
        map<string, bufferlist> aset;
        i.decode_attrset(aset);
        tracepoint(objectstore, omap_setkeys_enter, osr_name);
        r = _omap_setkeys(cid, oid, aset, spos);
        tracepoint(objectstore, omap_setkeys_exit, r);
      }
      break;
    case Transaction::OP_OMAP_RMKEYS:
      {
        const coll_t &_cid = i.get_cid(op->cid);
        const ghobject_t &oid = i.get_oid(op->oid);
        const coll_t &cid = !_need_temp_object_collection(_cid, oid) ?
          _cid : _cid.get_temp();
        set<string> keys;
        i.decode_keyset(keys);
        tracepoint(objectstore, omap_rmkeys_enter, osr_name);
        r = _omap_rmkeys(cid, oid, keys, spos);
        tracepoint(objectstore, omap_rmkeys_exit, r);
      }
      break;
    case Transaction::OP_OMAP_RMKEYRANGE:
      {
        const coll_t &_cid = i.get_cid(op->cid);
        const ghobject_t &oid = i.get_oid(op->oid);
        const coll_t &cid = !_need_temp_object_collection(_cid, oid) ?
          _cid : _cid.get_temp();
        string first, last;
        first = i.decode_string();
        last = i.decode_string();
        tracepoint(objectstore, omap_rmkeyrange_enter, osr_name);
        r = _omap_rmkeyrange(cid, oid, first, last, spos);
        tracepoint(objectstore, omap_rmkeyrange_exit, r);
      }
      break;
    case Transaction::OP_OMAP_SETHEADER:
      {
        const coll_t &_cid = i.get_cid(op->cid);
        const ghobject_t &oid = i.get_oid(op->oid);
        const coll_t &cid = !_need_temp_object_collection(_cid, oid) ?
          _cid : _cid.get_temp();
        bufferlist bl;
        i.decode_bl(bl);
        tracepoint(objectstore, omap_setheader_enter, osr_name);
        r = _omap_setheader(cid, oid, bl, spos);
        tracepoint(objectstore, omap_setheader_exit, r);
      }
      break;
    case Transaction::OP_SPLIT_COLLECTION:
      {
        assert(0 == "not legacy journal; upgrade to firefly first");
      }
      break;
    case Transaction::OP_SPLIT_COLLECTION2:
      {
        coll_t cid = i.get_cid(op->cid);
        uint32_t bits = op->split_bits;
        uint32_t rem = op->split_rem;
        coll_t dest = i.get_cid(op->dest_cid);
        tracepoint(objectstore, split_coll2_enter, osr_name);
        r = _split_collection(cid, bits, rem, dest, spos);
        tracepoint(objectstore, split_coll2_exit, r);
      }
      break;

    case Transaction::OP_SETALLOCHINT:
      {
        const coll_t &_cid = i.get_cid(op->cid);
        const ghobject_t &oid = i.get_oid(op->oid);
        const coll_t &cid = !_need_temp_object_collection(_cid, oid) ?
          _cid : _cid.get_temp();
        uint64_t expected_object_size = op->expected_object_size;
        uint64_t expected_write_size = op->expected_write_size;
        tracepoint(objectstore, setallochint_enter, osr_name);
        if (_check_replay_guard(cid, oid, spos) > 0)
          r = _set_alloc_hint(cid, oid, expected_object_size,
                              expected_write_size);
        tracepoint(objectstore, setallochint_exit, r);
      }
      break;

    default:
      derr << "bad op " << op->op << dendl;
      ceph_abort();
    }

    if (r < 0) {
      bool ok = false;

      if (r == -ENOENT && !(op->op == Transaction::OP_CLONERANGE ||
                            op->op == Transaction::OP_CLONE ||
                            op->op == Transaction::OP_CLONERANGE2 ||
                            op->op == Transaction::OP_COLL_ADD ||
                            op->op == Transaction::OP_SETATTR ||
                            op->op == Transaction::OP_SETATTRS ||
                            op->op == Transaction::OP_RMATTR ||
                            op->op == Transaction::OP_OMAP_SETKEYS ||
                            op->op == Transaction::OP_OMAP_RMKEYS ||
                            op->op == Transaction::OP_OMAP_RMKEYRANGE ||
                            op->op == Transaction::OP_OMAP_SETHEADER))
        // -ENOENT is normally okay
        // ...including on a replayed OP_RMCOLL with checkpoint mode
        ok = true;
      if (r == -ENODATA)
        ok = true;

      if (op->op == Transaction::OP_SETALLOCHINT)
        // Either EOPNOTSUPP or EINVAL most probably.  EINVAL in most
        // cases means invalid hint size (e.g. too big, not a multiple
        // of block size, etc) or, at least on xfs, an attempt to set
        // or change it when the file is not empty.  However,
        // OP_SETALLOCHINT is advisory, so ignore all errors.
        ok = true;

      if (replaying && !backend->can_checkpoint()) {
        if (r == -EEXIST && op->op == Transaction::OP_MKCOLL) {
          dout(10) << "tolerating EEXIST during journal replay since checkpoint is not enabled" << dendl;
          ok = true;
        }
        if (r == -EEXIST && op->op == Transaction::OP_COLL_ADD) {
          dout(10) << "tolerating EEXIST during journal replay since checkpoint is not enabled" << dendl;
          ok = true;
        }
        if (r == -EEXIST && op->op == Transaction::OP_COLL_MOVE) {
          dout(10) << "tolerating EEXIST during journal replay since checkpoint is not enabled" << dendl;
          ok = true;
        }
        if (r == -ERANGE) {
          dout(10) << "tolerating ERANGE on replay" << dendl;
          ok = true;
        }
        if (r == -ENOENT) {
          dout(10) << "tolerating ENOENT on replay" << dendl;
          ok = true;
        }
      }

      if (!ok) {
        const char *msg = "unexpected error code";

        if (r == -ENOENT && (op->op == Transaction::OP_CLONERANGE ||
                             op->op == Transaction::OP_CLONE ||
                             op->op == Transaction::OP_CLONERANGE2)) {
          msg = "ENOENT on clone suggests osd bug";
        } else if (r == -ENOSPC) {
          // For now, if we hit _any_ ENOSPC, crash, before we do any damage
          // by partially applying transactions.
          msg = "ENOSPC from disk filesystem, misconfigured cluster";
        } else if (r == -ENOTEMPTY) {
          msg = "ENOTEMPTY suggests garbage data in osd data dir";
        } else if (r == -EPERM) {
          msg = "EPERM suggests file(s) in osd data dir not owned by ceph user, or leveldb corruption";
        }

        derr  << " error " << cpp_strerror(r) << " not handled on operation " << op
              << " (" << spos << ", or op " << spos.op << ", counting from 0)" << dendl;
        dout(0) << msg << dendl;
        dout(0) << " transaction dump:\n";
        JSONFormatter f(true);
        f.open_object_section("transaction");
        t.dump(&f);
        f.close_section();
        f.flush(*_dout);
        *_dout << dendl;

        if (r == -EMFILE) {
          dump_open_fds(cct);
        }

        assert(0 == "unexpected error");
      }
    }

    spos.op++;
  }

  _inject_failure();
}

  /*********************************************/



// --------------------
// objects

bool FileStore::exists(const coll_t& _cid, const ghobject_t& oid)
{
  tracepoint(objectstore, exists_enter, _cid.c_str());
  const coll_t& cid = !_need_temp_object_collection(_cid, oid) ? _cid : _cid.get_temp();
  struct stat st;
  bool retval = stat(cid, oid, &st) == 0;
  tracepoint(objectstore, exists_exit, retval);
  return retval;
}

int FileStore::stat(
  const coll_t& _cid, const ghobject_t& oid, struct stat *st, bool allow_eio)
{
  tracepoint(objectstore, stat_enter, _cid.c_str());
  const coll_t& cid = !_need_temp_object_collection(_cid, oid) ? _cid : _cid.get_temp();
  int r = lfn_stat(cid, oid, st);
  assert(allow_eio || !m_filestore_fail_eio || r != -EIO);
  if (r < 0) {
    dout(10) << "stat " << cid << "/" << oid
             << " = " << r << dendl;
  } else {
    dout(10) << "stat " << cid << "/" << oid
             << " = " << r
             << " (size " << st->st_size << ")" << dendl;
  }
  if (cct->_conf->filestore_debug_inject_read_err &&
      debug_mdata_eio(oid)) {
    return -EIO;
  } else {
    tracepoint(objectstore, stat_exit, r);
    return r;
  }
}

int FileStore::set_collection_opts(
  const coll_t& cid,
  const pool_opts_t& opts)
{
  return -EOPNOTSUPP;
}

int FileStore::read(
  const coll_t& _cid,
  const ghobject_t& oid,
  uint64_t offset,
  size_t len,
  bufferlist& bl,
  uint32_t op_flags,
  bool allow_eio)
{
  int got;
  tracepoint(objectstore, read_enter, _cid.c_str(), offset, len);
  const coll_t& cid = !_need_temp_object_collection(_cid, oid) ? _cid : _cid.get_temp();

  dout(15) << "read " << cid << "/" << oid << " " << offset << "~" << len << dendl;

  FDRef fd;
  int r = lfn_open(cid, oid, false, &fd);
  if (r < 0) {
    dout(10) << "FileStore::read(" << cid << "/" << oid << ") open error: "
             << cpp_strerror(r) << dendl;
    return r;
  }

  if (offset == 0 && len == 0) {
    struct stat st;
    memset(&st, 0, sizeof(struct stat));
    int r = ::fstat(**fd, &st);
    assert(r == 0);
    len = st.st_size;
  }

#ifdef HAVE_POSIX_FADVISE
  if (op_flags & CEPH_OSD_OP_FLAG_FADVISE_RANDOM)
    posix_fadvise(**fd, offset, len, POSIX_FADV_RANDOM);
  if (op_flags & CEPH_OSD_OP_FLAG_FADVISE_SEQUENTIAL)
    posix_fadvise(**fd, offset, len, POSIX_FADV_SEQUENTIAL);
#endif

  bufferptr bptr(len);  // prealloc space for entire read
  got = safe_pread(**fd, bptr.c_str(), len, offset);
  if (got < 0) {
    dout(10) << "FileStore::read(" << cid << "/" << oid << ") pread error: " << cpp_strerror(got) << dendl;
    lfn_close(fd);
    if (!(allow_eio || !m_filestore_fail_eio || got != -EIO)) {
      derr << "FileStore::read(" << cid << "/" << oid << ") pread error: " << cpp_strerror(got) << dendl;
      assert(0 == "eio on pread");
    }
    return got;
  }
  bptr.set_length(got);   // properly size the buffer
  bl.clear();
  bl.push_back(std::move(bptr));   // put it in the target bufferlist

#ifdef HAVE_POSIX_FADVISE
  if (op_flags & CEPH_OSD_OP_FLAG_FADVISE_DONTNEED)
    posix_fadvise(**fd, offset, len, POSIX_FADV_DONTNEED);
  if (op_flags & (CEPH_OSD_OP_FLAG_FADVISE_RANDOM | CEPH_OSD_OP_FLAG_FADVISE_SEQUENTIAL))
    posix_fadvise(**fd, offset, len, POSIX_FADV_NORMAL);
#endif

  if (m_filestore_sloppy_crc && (!replaying || backend->can_checkpoint())) {
    ostringstream ss;
    int errors = backend->_crc_verify_read(**fd, offset, got, bl, &ss);
    if (errors != 0) {
      dout(0) << "FileStore::read " << cid << "/" << oid << " " << offset << "~"
              << got << " ... BAD CRC:\n" << ss.str() << dendl;
      assert(0 == "bad crc on read");
    }
  }

  lfn_close(fd);

  dout(10) << "FileStore::read " << cid << "/" << oid << " " << offset << "~"
           << got << "/" << len << dendl;
  if (cct->_conf->filestore_debug_inject_read_err &&
      debug_data_eio(oid)) {
    return -EIO;
  } else {
    tracepoint(objectstore, read_exit, got);
    return got;
  }
}

int FileStore::_do_fiemap(int fd, uint64_t offset, size_t len,
                          map<uint64_t, uint64_t> *m)
{
  uint64_t i;
  struct fiemap_extent *extent = NULL;
  struct fiemap *fiemap = NULL;
  int r = 0;

more:
  r = backend->do_fiemap(fd, offset, len, &fiemap);
  if (r < 0)
    return r;

  if (fiemap->fm_mapped_extents == 0) {
    free(fiemap);
    return r;
  }

  extent = &fiemap->fm_extents[0];

  /* start where we were asked to start */
  if (extent->fe_logical < offset) {
    extent->fe_length -= offset - extent->fe_logical;
    extent->fe_logical = offset;
  }

  i = 0;

  struct fiemap_extent *last = nullptr;
  while (i < fiemap->fm_mapped_extents) {
    struct fiemap_extent *next = extent + 1;

    dout(10) << "FileStore::fiemap() fm_mapped_extents=" << fiemap->fm_mapped_extents
             << " fe_logical=" << extent->fe_logical << " fe_length=" << extent->fe_length << dendl;

    /* try to merge extents */
    while ((i < fiemap->fm_mapped_extents - 1) &&
           (extent->fe_logical + extent->fe_length == next->fe_logical)) {
        next->fe_length += extent->fe_length;
        next->fe_logical = extent->fe_logical;
        extent = next;
        next = extent + 1;
        i++;
    }

    if (extent->fe_logical + extent->fe_length > offset + len)
      extent->fe_length = offset + len - extent->fe_logical;
    (*m)[extent->fe_logical] = extent->fe_length;
    i++;
    last = extent++;
  }
  uint64_t xoffset = last->fe_logical + last->fe_length - offset;
  offset = last->fe_logical + last->fe_length;
  len -= xoffset;
  const bool is_last = (last->fe_flags & FIEMAP_EXTENT_LAST) || (len == 0);
  free(fiemap);
  if (!is_last) {
    goto more;
  }

  return r;
}

int FileStore::_do_seek_hole_data(int fd, uint64_t offset, size_t len,
                                  map<uint64_t, uint64_t> *m)
{
#if defined(__linux__) && defined(SEEK_HOLE) && defined(SEEK_DATA)
  off_t hole_pos, data_pos;
  int r = 0;

  // If lseek fails with errno setting to be ENXIO, this means the current
  // file offset is beyond the end of the file.
  off_t start = offset;
  while(start < (off_t)(offset + len)) {
    data_pos = lseek(fd, start, SEEK_DATA);
    if (data_pos < 0) {
      if (errno == ENXIO)
        break;
      else {
        r = -errno;
        dout(10) << "failed to lseek: " << cpp_strerror(r) << dendl;
        return r;
      }
    } else if (data_pos > (off_t)(offset + len)) {
      break;
    }

    hole_pos = lseek(fd, data_pos, SEEK_HOLE);
    if (hole_pos < 0) {
      if (errno == ENXIO) {
        break;
      } else {
        r = -errno;
        dout(10) << "failed to lseek: " << cpp_strerror(r) << dendl;
        return r;
      }
    }

    if (hole_pos >= (off_t)(offset + len)) {
      (*m)[data_pos] = offset + len - data_pos;
      break;
    }
    (*m)[data_pos] = hole_pos - data_pos;
    start = hole_pos;
  }

  return r;
#else
  (*m)[offset] = len;
  return 0;
#endif
}

int FileStore::fiemap(const coll_t& _cid, const ghobject_t& oid,
                    uint64_t offset, size_t len,
                    bufferlist& bl)
{
  map<uint64_t, uint64_t> exomap;
  int r = fiemap(_cid, oid, offset, len, exomap);
  if (r >= 0) {
    ::encode(exomap, bl);
  }
  return r;
}

int FileStore::fiemap(const coll_t& _cid, const ghobject_t& oid,
                    uint64_t offset, size_t len,
                    map<uint64_t, uint64_t>& destmap)
{
  tracepoint(objectstore, fiemap_enter, _cid.c_str(), offset, len);
  const coll_t& cid = !_need_temp_object_collection(_cid, oid) ? _cid : _cid.get_temp();
  destmap.clear();

  if ((!backend->has_seek_data_hole() && !backend->has_fiemap()) ||
      len <= (size_t)m_filestore_fiemap_threshold) {
    destmap[offset] = len;
    return 0;
  }

  dout(15) << "fiemap " << cid << "/" << oid << " " << offset << "~" << len << dendl;

  FDRef fd;

  int r = lfn_open(cid, oid, false, &fd);
  if (r < 0) {
    dout(10) << "read couldn't open " << cid << "/" << oid << ": " << cpp_strerror(r) << dendl;
    goto done;
  }

  if (backend->has_seek_data_hole()) {
    dout(15) << "seek_data/seek_hole " << cid << "/" << oid << " " << offset << "~" << len << dendl;
    r = _do_seek_hole_data(**fd, offset, len, &destmap);
  } else if (backend->has_fiemap()) {
    dout(15) << "fiemap ioctl" << cid << "/" << oid << " " << offset << "~" << len << dendl;
    r = _do_fiemap(**fd, offset, len, &destmap);
  }

  lfn_close(fd);

done:

  dout(10) << "fiemap " << cid << "/" << oid << " " << offset << "~" << len << " = " << r << " num_extents=" << destmap.size() << " " << destmap << dendl;
  assert(!m_filestore_fail_eio || r != -EIO);
  tracepoint(objectstore, fiemap_exit, r);
  return r;
}

int FileStore::_remove(const coll_t& cid, const ghobject_t& oid,
                       const SequencerPosition &spos)
{
  dout(15) << "remove " << cid << "/" << oid << dendl;
  int r = lfn_unlink(cid, oid, spos);
  dout(10) << "remove " << cid << "/" << oid << " = " << r << dendl;
  return r;
}

int FileStore::_truncate(const coll_t& cid, const ghobject_t& oid, uint64_t size)
{
  dout(15) << "truncate " << cid << "/" << oid << " size " << size << dendl;
  int r = lfn_truncate(cid, oid, size);
  dout(10) << "truncate " << cid << "/" << oid << " size " << size << " = " << r << dendl;
  return r;
}


int FileStore::_touch(const coll_t& cid, const ghobject_t& oid)
{
  dout(15) << "touch " << cid << "/" << oid << dendl;

  FDRef fd;
  int r = lfn_open(cid, oid, true, &fd);
  if (r < 0) {
    return r;
  } else {
    lfn_close(fd);
  }
  dout(10) << "touch " << cid << "/" << oid << " = " << r << dendl;
  return r;
}

int FileStore::_write(const coll_t& cid, const ghobject_t& oid,
                     uint64_t offset, size_t len,
                     const bufferlist& bl, uint32_t fadvise_flags)
{
  dout(15) << "write " << cid << "/" << oid << " " << offset << "~" << len << dendl;
  int r;

  FDRef fd;
  r = lfn_open(cid, oid, true, &fd);
  if (r < 0) {
    dout(0) << "write couldn't open " << cid << "/"
            << oid << ": "
            << cpp_strerror(r) << dendl;
    goto out;
  }

  // write
  r = bl.write_fd(**fd, offset);
  if (r < 0) {
    derr << __func__ << " write_fd on " << cid << "/" << oid
         << " error: " << cpp_strerror(r) << dendl;
    lfn_close(fd);
    goto out;
  }
  r = bl.length();

  if (r >= 0 && m_filestore_sloppy_crc) {
    int rc = backend->_crc_update_write(**fd, offset, len, bl);
    assert(rc >= 0);
  }
 
  if (replaying || m_disable_wbthrottle) {
    if (fadvise_flags & CEPH_OSD_OP_FLAG_FADVISE_DONTNEED) {
#ifdef HAVE_POSIX_FADVISE
        posix_fadvise(**fd, 0, 0, POSIX_FADV_DONTNEED);
#endif
    }
  } else {
    wbthrottle.queue_wb(fd, oid, offset, len,
        fadvise_flags & CEPH_OSD_OP_FLAG_FADVISE_DONTNEED);
  }
 
  lfn_close(fd);

 out:
  dout(10) << "write " << cid << "/" << oid << " " << offset << "~" << len << " = " << r << dendl;
  return r;
}

int FileStore::_zero(const coll_t& cid, const ghobject_t& oid, uint64_t offset, size_t len)
{
  dout(15) << "zero " << cid << "/" << oid << " " << offset << "~" << len << dendl;
  int ret = 0;

  if (cct->_conf->filestore_punch_hole) {
#ifdef CEPH_HAVE_FALLOCATE
# if !defined(DARWIN) && !defined(__FreeBSD__)
#    ifdef FALLOC_FL_KEEP_SIZE
    // first try to punch a hole.
    FDRef fd;
    ret = lfn_open(cid, oid, false, &fd);
    if (ret < 0) {
      goto out;
    }

    struct stat st;
    ret = ::fstat(**fd, &st);
    if (ret < 0) {
      ret = -errno;
      lfn_close(fd);
      goto out;
    }

    // first try fallocate
    ret = fallocate(**fd, FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE,
                    offset, len);
    if (ret < 0) {
      ret = -errno;
    } else {
      // ensure we extent file size, if needed
      if (offset + len > (uint64_t)st.st_size) {
        ret = ::ftruncate(**fd, offset + len);
        if (ret < 0) {
          ret = -errno;
          lfn_close(fd);
          goto out;
        }
      }
    }
    lfn_close(fd);

    if (ret >= 0 && m_filestore_sloppy_crc) {
      int rc = backend->_crc_update_zero(**fd, offset, len);
      assert(rc >= 0);
    }

    if (ret == 0)
      goto out;  // yay!
    if (ret != -EOPNOTSUPP)
      goto out;  // some other error
#    endif
# endif
#endif
  }

  // lame, kernel is old and doesn't support it.
  // write zeros.. yuck!
  dout(20) << "zero falling back to writing zeros" << dendl;
  {
    bufferlist bl;
    bl.append_zero(len);
    ret = _write(cid, oid, offset, len, bl);
  }

#ifdef CEPH_HAVE_FALLOCATE
# if !defined(DARWIN) && !defined(__FreeBSD__)
#    ifdef FALLOC_FL_KEEP_SIZE
 out:
#    endif
# endif
#endif
  dout(20) << "zero " << cid << "/" << oid << " " << offset << "~" << len << " = " << ret << dendl;
  return ret;
}

int FileStore::_clone(const coll_t& cid, const ghobject_t& oldoid, const ghobject_t& newoid,
                      const SequencerPosition& spos)
{
  dout(15) << "clone " << cid << "/" << oldoid << " -> " << cid << "/" << newoid << dendl;

  if (_check_replay_guard(cid, newoid, spos) < 0)
    return 0;

  int r;
  FDRef o, n;
  {
    Index index;
    r = lfn_open(cid, oldoid, false, &o, &index);
    if (r < 0) {
      goto out2;
    }
    assert(NULL != (index.index));
    RWLock::WLocker l((index.index)->access_lock);

    r = lfn_open(cid, newoid, true, &n, &index);
    if (r < 0) {
      goto out;
    }
    r = ::ftruncate(**n, 0);
    if (r < 0) {
      r = -errno;
      goto out3;
    }
    struct stat st;
    r = ::fstat(**o, &st);
    if (r < 0) {
      r = -errno;
      goto out3;
    }

    r = _do_clone_range(**o, **n, 0, st.st_size, 0);
    if (r < 0) {
      goto out3;
    }

    dout(20) << "objectmap clone" << dendl;
    r = object_map->clone(oldoid, newoid, &spos);
    if (r < 0 && r != -ENOENT)
      goto out3;
  }

  {
    char buf[2];
    map<string, bufferptr> aset;
    r = _fgetattrs(**o, aset);
    if (r < 0)
      goto out3;

    r = chain_fgetxattr(**o, XATTR_SPILL_OUT_NAME, buf, sizeof(buf));
    if (r >= 0 && !strncmp(buf, XATTR_NO_SPILL_OUT, sizeof(XATTR_NO_SPILL_OUT))) {
      r = chain_fsetxattr<true, true>(**n, XATTR_SPILL_OUT_NAME, XATTR_NO_SPILL_OUT,
                          sizeof(XATTR_NO_SPILL_OUT));
    } else {
      r = chain_fsetxattr<true, true>(**n, XATTR_SPILL_OUT_NAME, XATTR_SPILL_OUT,
                          sizeof(XATTR_SPILL_OUT));
    }
    if (r < 0)
      goto out3;

    r = _fsetattrs(**n, aset);
    if (r < 0)
      goto out3;
  }

  // clone is non-idempotent; record our work.
  _set_replay_guard(**n, spos, &newoid);

 out3:
  lfn_close(n);
 out:
  lfn_close(o);
 out2:
  dout(10) << "clone " << cid << "/" << oldoid << " -> " << cid << "/" << newoid << " = " << r << dendl;
  assert(!m_filestore_fail_eio || r != -EIO);
  return r;
}

int FileStore::_do_clone_range(int from, int to, uint64_t srcoff, uint64_t len, uint64_t dstoff)
{
  dout(20) << "_do_clone_range copy " << srcoff << "~" << len << " to " << dstoff << dendl;
  return backend->clone_range(from, to, srcoff, len, dstoff);
}

int FileStore::_do_sparse_copy_range(int from, int to, uint64_t srcoff, uint64_t len, uint64_t dstoff)
{
  dout(20) << __func__ << " " << srcoff << "~" << len << " to " << dstoff << dendl;
  int r = 0;
  map<uint64_t, uint64_t> exomap;
  // fiemap doesn't allow zero length
  if (len == 0)
    return 0;

  if (backend->has_seek_data_hole()) {
    dout(15) << "seek_data/seek_hole " << from << " " << srcoff << "~" << len << dendl;
    r = _do_seek_hole_data(from, srcoff, len, &exomap);
  } else if (backend->has_fiemap()) {
    dout(15) << "fiemap ioctl" << from << " " << srcoff << "~" << len << dendl;
    r = _do_fiemap(from, srcoff, len, &exomap);
  }

 
 int64_t written = 0;
 if (r < 0)
    goto out;

  for (map<uint64_t, uint64_t>::iterator miter = exomap.begin(); miter != exomap.end(); ++miter) {
    uint64_t it_off = miter->first - srcoff + dstoff;
    r = _do_copy_range(from, to, miter->first, miter->second, it_off, true);
    if (r < 0) {
      derr << "FileStore::_do_copy_range: copy error at " << miter->first << "~" << miter->second
             << " to " << it_off << ", " << cpp_strerror(r) << dendl;
      break;
    }
    written += miter->second;
  }

  if (r >= 0) {
    if (m_filestore_sloppy_crc) {
      int rc = backend->_crc_update_clone_range(from, to, srcoff, len, dstoff);
      assert(rc >= 0);
    }
    struct stat st;
    r = ::fstat(to, &st);
    if (r < 0) {
      r = -errno;
      derr << __func__ << ": fstat error at " << to << " " << cpp_strerror(r) << dendl;
      goto out;
    }
    if (st.st_size < (int)(dstoff + len)) {
      r = ::ftruncate(to, dstoff + len);
      if (r < 0) {
        r = -errno;
        derr << __func__ << ": ftruncate error at " << dstoff+len << " " << cpp_strerror(r) << dendl;
        goto out;
      }
    }
    r = written;
  }

 out:
  dout(20) << __func__ << " " << srcoff << "~" << len << " to " << dstoff << " = " << r << dendl;
  return r;
}

int FileStore::_do_copy_range(int from, int to, uint64_t srcoff, uint64_t len, uint64_t dstoff, bool skip_sloppycrc)
{
  dout(20) << "_do_copy_range " << srcoff << "~" << len << " to " << dstoff << dendl;
  int r = 0;
  loff_t pos = srcoff;
  loff_t end = srcoff + len;
  int buflen = 4096 * 16; //limit by pipe max size.see fcntl

#ifdef CEPH_HAVE_SPLICE
  if (backend->has_splice()) {
    int pipefd[2];
    if (pipe(pipefd) < 0) {
      r = -errno;
      derr << " pipe " << " got " << cpp_strerror(r) << dendl;
      return r;
    }

    loff_t dstpos = dstoff;
    while (pos < end) {
      int l = MIN(end-pos, buflen);
      r = safe_splice(from, &pos, pipefd[1], NULL, l, SPLICE_F_NONBLOCK);
      dout(10) << "  safe_splice read from " << pos << "~" << l << " got " << r << dendl;
      if (r < 0) {
        derr << "FileStore::_do_copy_range: safe_splice read error at " << pos << "~" << len
          << ", " << cpp_strerror(r) << dendl;
        break;
      }
      if (r == 0) {
        // hrm, bad source range, wtf.
        r = -ERANGE;
        derr << "FileStore::_do_copy_range got short read result at " << pos
          << " of fd " << from << " len " << len << dendl;
        break;
      }

      r = safe_splice(pipefd[0], NULL, to, &dstpos, r, 0);
      dout(10) << " safe_splice write to " << to << " len " << r
        << " got " << r << dendl;
      if (r < 0) {
        derr << "FileStore::_do_copy_range: write error at " << pos << "~"
          << r << ", " << cpp_strerror(r) << dendl;
        break;
      }
    }
    close(pipefd[0]);
    close(pipefd[1]);
  } else
#endif
  {
    int64_t actual;

    actual = ::lseek64(from, srcoff, SEEK_SET);
    if (actual != (int64_t)srcoff) {
      if (actual < 0)
        r = -errno;
      else
        r = -EINVAL;
      derr << "lseek64 to " << srcoff << " got " << cpp_strerror(r) << dendl;
      return r;
    }
    actual = ::lseek64(to, dstoff, SEEK_SET);
    if (actual != (int64_t)dstoff) {
      if (actual < 0)
        r = -errno;
      else
        r = -EINVAL;
      derr << "lseek64 to " << dstoff << " got " << cpp_strerror(r) << dendl;
      return r;
    }

    char buf[buflen];
    while (pos < end) {
      int l = MIN(end-pos, buflen);
      r = ::read(from, buf, l);
      dout(25) << "  read from " << pos << "~" << l << " got " << r << dendl;
      if (r < 0) {
        if (errno == EINTR) {
          continue;
        } else {
          r = -errno;
          derr << "FileStore::_do_copy_range: read error at " << pos << "~" << len
            << ", " << cpp_strerror(r) << dendl;
          break;
        }
      }
      if (r == 0) {
        // hrm, bad source range, wtf.
        r = -ERANGE;
        derr << "FileStore::_do_copy_range got short read result at " << pos
          << " of fd " << from << " len " << len << dendl;
        break;
      }
      int op = 0;
      while (op < r) {
        int r2 = safe_write(to, buf+op, r-op);
        dout(25) << " write to " << to << " len " << (r-op)
          << " got " << r2 << dendl;
        if (r2 < 0) {
          r = r2;
          derr << "FileStore::_do_copy_range: write error at " << pos << "~"
            << r-op << ", " << cpp_strerror(r) << dendl;

          break;
        }
        op += (r-op);
      }
      if (r < 0)
        break;
      pos += r;
    }
  }

  if (r < 0 && replaying) {
    assert(r == -ERANGE);
    derr << "Filestore: short source tolerated because we are replaying" << dendl;
    r = pos - from;;
  }
  assert(replaying || pos == end);
  if (r >= 0 && !skip_sloppycrc && m_filestore_sloppy_crc) {
    int rc = backend->_crc_update_clone_range(from, to, srcoff, len, dstoff);
    assert(rc >= 0);
  }
  dout(20) << "_do_copy_range " << srcoff << "~" << len << " to " << dstoff << " = " << r << dendl;
  return r;
}

int FileStore::_clone_range(const coll_t& oldcid, const ghobject_t& oldoid, const coll_t& newcid, const ghobject_t& newoid,
                            uint64_t srcoff, uint64_t len, uint64_t dstoff,
                            const SequencerPosition& spos)
{
  dout(15) << "clone_range " << oldcid << "/" << oldoid << " -> " << newcid << "/" << newoid << " " << srcoff << "~" << len << " to " << dstoff << dendl;

  if (_check_replay_guard(newcid, newoid, spos) < 0)
    return 0;

  int r;
  FDRef o, n;
  r = lfn_open(oldcid, oldoid, false, &o);
  if (r < 0) {
    goto out2;
  }
  r = lfn_open(newcid, newoid, true, &n);
  if (r < 0) {
    goto out;
  }
  r = _do_clone_range(**o, **n, srcoff, len, dstoff);
  if (r < 0) {
    goto out3;
  }

  // clone is non-idempotent; record our work.
  _set_replay_guard(**n, spos, &newoid);

 out3:
  lfn_close(n);
 out:
  lfn_close(o);
 out2:
  dout(10) << "clone_range " << oldcid << "/" << oldoid << " -> " << newcid << "/" << newoid << " "
           << srcoff << "~" << len << " to " << dstoff << " = " << r << dendl;
  return r;
}

class SyncEntryTimeout : public Context {
public:
  CephContext* cct;
  explicit SyncEntryTimeout(CephContext* cct, int commit_timeo)
    : cct(cct), m_commit_timeo(commit_timeo)
  {
  }

  void finish(int r) override {
    BackTrace *bt = new BackTrace(1);
    generic_dout(-1) << "FileStore: sync_entry timed out after "
           << m_commit_timeo << " seconds.\n";
    bt->print(*_dout);
    *_dout << dendl;
    delete bt;
    ceph_abort();
  }
private:
  int m_commit_timeo;
};

void FileStore::sync_entry()
{
  lock.Lock();
  while (!stop) {
    utime_t max_interval;
    max_interval.set_from_double(m_filestore_max_sync_interval);
    utime_t min_interval;
    min_interval.set_from_double(m_filestore_min_sync_interval);

    utime_t startwait = ceph_clock_now();
    if (!force_sync) {
      dout(20) << "sync_entry waiting for max_interval " << max_interval << dendl;
      sync_cond.WaitInterval(lock, max_interval);
    } else {
      dout(20) << "sync_entry not waiting, force_sync set" << dendl;
    }

    if (force_sync) {
      dout(20) << "sync_entry force_sync set" << dendl;
      force_sync = false;
    } else if (stop) {
      dout(20) << __func__ << " stop set" << dendl;
      break;
    } else {
      // wait for at least the min interval
      utime_t woke = ceph_clock_now();
      woke -= startwait;
      dout(20) << "sync_entry woke after " << woke << dendl;
      if (woke < min_interval) {
        utime_t t = min_interval;
        t -= woke;
        dout(20) << "sync_entry waiting for another " << t
                 << " to reach min interval " << min_interval << dendl;
        sync_cond.WaitInterval(lock, t);
      }
    }

    list<Context*> fin;
  again:
    fin.swap(sync_waiters);
    lock.Unlock();

    op_tp.pause();
    if (apply_manager.commit_start()) {
      utime_t start = ceph_clock_now();
      uint64_t cp = apply_manager.get_committing_seq();

      sync_entry_timeo_lock.Lock();
      SyncEntryTimeout *sync_entry_timeo =
        new SyncEntryTimeout(cct, m_filestore_commit_timeout);
      timer.add_event_after(m_filestore_commit_timeout, sync_entry_timeo);
      sync_entry_timeo_lock.Unlock();

      logger->set(l_filestore_committing, 1);

      dout(15) << "sync_entry committing " << cp << dendl;
      stringstream errstream;
      if (cct->_conf->filestore_debug_omap_check && !object_map->check(errstream)) {
        derr << errstream.str() << dendl;
        ceph_abort();
      }

      if (backend->can_checkpoint()) {
        int err = write_op_seq(op_fd, cp);
        if (err < 0) {
          derr << "Error during write_op_seq: " << cpp_strerror(err) << dendl;
          assert(0 == "error during write_op_seq");
        }

        char s[NAME_MAX];
        snprintf(s, sizeof(s), COMMIT_SNAP_ITEM, (long long unsigned)cp);
        uint64_t cid = 0;
        err = backend->create_checkpoint(s, &cid);
        if (err < 0) {
            int err = errno;
            derr << "snap create '" << s << "' got error " << err << dendl;
            assert(err == 0);
        }

        snaps.push_back(cp);
        apply_manager.commit_started();
        op_tp.unpause();

        if (cid > 0) {
          dout(20) << " waiting for checkpoint " << cid << " to complete" << dendl;
          err = backend->sync_checkpoint(cid);
          if (err < 0) {
            derr << "ioctl WAIT_SYNC got " << cpp_strerror(err) << dendl;
            assert(0 == "wait_sync got error");
          }
          dout(20) << " done waiting for checkpoint " << cid << " to complete" << dendl;
        }
      } else
      {
        apply_manager.commit_started();
        op_tp.unpause();

        int err = object_map->sync();
        if (err < 0) {
          derr << "object_map sync got " << cpp_strerror(err) << dendl;
          assert(0 == "object_map sync returned error");
        }

        err = backend->syncfs();
        if (err < 0) {
          derr << "syncfs got " << cpp_strerror(err) << dendl;
          assert(0 == "syncfs returned error");
        }

        err = write_op_seq(op_fd, cp);
        if (err < 0) {
          derr << "Error during write_op_seq: " << cpp_strerror(err) << dendl;
          assert(0 == "error during write_op_seq");
        }
        err = ::fsync(op_fd);
        if (err < 0) {
          derr << "Error during fsync of op_seq: " << cpp_strerror(err) << dendl;
          assert(0 == "error during fsync of op_seq");
        }
      }

      utime_t done = ceph_clock_now();
      utime_t lat = done - start;
      utime_t dur = done - startwait;
      dout(10) << "sync_entry commit took " << lat << ", interval was " << dur << dendl;

      logger->inc(l_filestore_commitcycle);
      logger->tinc(l_filestore_commitcycle_latency, lat);
      logger->tinc(l_filestore_commitcycle_interval, dur);

      apply_manager.commit_finish();
      if (!m_disable_wbthrottle) {
        wbthrottle.clear();
      }

      logger->set(l_filestore_committing, 0);

      // remove old snaps?
      if (backend->can_checkpoint()) {
        char s[NAME_MAX];
        while (snaps.size() > 2) {
          snprintf(s, sizeof(s), COMMIT_SNAP_ITEM, (long long unsigned)snaps.front());
          snaps.pop_front();
          dout(10) << "removing snap '" << s << "'" << dendl;
          int r = backend->destroy_checkpoint(s);
          if (r) {
            int err = errno;
            derr << "unable to destroy snap '" << s << "' got " << cpp_strerror(err) << dendl;
          }
        }
      }

      dout(15) << "sync_entry committed to op_seq " << cp << dendl;

      sync_entry_timeo_lock.Lock();
      timer.cancel_event(sync_entry_timeo);
      sync_entry_timeo_lock.Unlock();
    } else {
      op_tp.unpause();
    }

    lock.Lock();
    finish_contexts(cct, fin, 0);
    fin.clear();
    if (!sync_waiters.empty()) {
      dout(10) << "sync_entry more waiters, committing again" << dendl;
      goto again;
    }
    if (!stop && journal && journal->should_commit_now()) {
      dout(10) << "sync_entry journal says we should commit again (probably is/was full)" << dendl;
      goto again;
    }
  }
  stop = false;
  lock.Unlock();
}

void FileStore::_start_sync()
{
  if (!journal) {  // don't do a big sync if the journal is on
    dout(10) << "start_sync" << dendl;
    sync_cond.Signal();
  } else {
    dout(10) << "start_sync - NOOP (journal is on)" << dendl;
  }
}

void FileStore::do_force_sync()
{
  dout(10) << __func__ << dendl;
  Mutex::Locker l(lock);
  force_sync = true;
  sync_cond.Signal();
}

void FileStore::start_sync(Context *onsafe)
{
  Mutex::Locker l(lock);
  sync_waiters.push_back(onsafe);
  sync_cond.Signal();
  force_sync = true;
  dout(10) << "start_sync" << dendl;
}

void FileStore::sync()
{
  Mutex l("FileStore::sync");
  Cond c;
  bool done;
  C_SafeCond *fin = new C_SafeCond(&l, &c, &done);

  start_sync(fin);

  l.Lock();
  while (!done) {
    dout(10) << "sync waiting" << dendl;
    c.Wait(l);
  }
  l.Unlock();
  dout(10) << "sync done" << dendl;
}

void FileStore::_flush_op_queue()
{
  dout(10) << "_flush_op_queue draining op tp" << dendl;
  op_wq.drain();
  dout(10) << "_flush_op_queue waiting for apply finisher" << dendl;
  for (vector<Finisher*>::iterator it = apply_finishers.begin(); it != apply_finishers.end(); ++it) {
    (*it)->wait_for_empty();
  }
}

/*
 * flush - make every queued write readable
 */
void FileStore::flush()
{
  dout(10) << "flush" << dendl;

  if (cct->_conf->filestore_blackhole) {
    // wait forever
    Mutex lock("FileStore::flush::lock");
    Cond cond;
    lock.Lock();
    while (true)
      cond.Wait(lock);
    ceph_abort();
  }

  if (m_filestore_journal_writeahead) {
    if (journal)
      journal->flush();
    dout(10) << "flush draining ondisk finisher" << dendl;
    for (vector<Finisher*>::iterator it = ondisk_finishers.begin(); it != ondisk_finishers.end(); ++it) {
      (*it)->wait_for_empty();
    }
  }

  _flush_op_queue();
  dout(10) << "flush complete" << dendl;
}

/*
 * sync_and_flush - make every queued write readable AND committed to disk
 */
void FileStore::sync_and_flush()
{
  dout(10) << "sync_and_flush" << dendl;

  if (m_filestore_journal_writeahead) {
    if (journal)
      journal->flush();
    _flush_op_queue();
  } else {
    // includes m_filestore_journal_parallel
    _flush_op_queue();
    sync();
  }
  dout(10) << "sync_and_flush done" << dendl;
}

int FileStore::flush_journal()
{
  dout(10) << __func__ << dendl;
  sync_and_flush();
  sync();
  return 0;
}

int FileStore::snapshot(const string& name)
{
  dout(10) << "snapshot " << name << dendl;
  sync_and_flush();

  if (!backend->can_checkpoint()) {
    dout(0) << "snapshot " << name << " failed, not supported" << dendl;
    return -EOPNOTSUPP;
  }

  char s[NAME_MAX];
  snprintf(s, sizeof(s), CLUSTER_SNAP_ITEM, name.c_str());

  int r = backend->create_checkpoint(s, NULL);
  if (r) {
    derr << "snapshot " << name << " failed: " << cpp_strerror(r) << dendl;
  }

  return r;
}

// -------------------------------
// attributes

int FileStore::_fgetattr(int fd, const char *name, bufferptr& bp)
{
  char val[CHAIN_XATTR_MAX_BLOCK_LEN];
  int l = chain_fgetxattr(fd, name, val, sizeof(val));
  if (l >= 0) {
    bp = buffer::create(l);
    memcpy(bp.c_str(), val, l);
  } else if (l == -ERANGE) {
    l = chain_fgetxattr(fd, name, 0, 0);
    if (l > 0) {
      bp = buffer::create(l);
      l = chain_fgetxattr(fd, name, bp.c_str(), l);
    }
  }
  assert(!m_filestore_fail_eio || l != -EIO);
  return l;
}

int FileStore::_fgetattrs(int fd, map<string,bufferptr>& aset)
{
  // get attr list
  char names1[100];
  int len = chain_flistxattr(fd, names1, sizeof(names1)-1);
  char *names2 = 0;
  char *name = 0;
  if (len == -ERANGE) {
    len = chain_flistxattr(fd, 0, 0);
    if (len < 0) {
      assert(!m_filestore_fail_eio || len != -EIO);
      return len;
    }
    dout(10) << " -ERANGE, len is " << len << dendl;
    names2 = new char[len+1];
    len = chain_flistxattr(fd, names2, len);
    dout(10) << " -ERANGE, got " << len << dendl;
    if (len < 0) {
      assert(!m_filestore_fail_eio || len != -EIO);
      delete[] names2;
      return len;
    }
    name = names2;
  } else if (len < 0) {
    assert(!m_filestore_fail_eio || len != -EIO);
    return len;
  } else {
    name = names1;
  }
  name[len] = 0;

  char *end = name + len;
  while (name < end) {
    char *attrname = name;
    if (parse_attrname(&name)) {
      if (*name) {
        dout(20) << "fgetattrs " << fd << " getting '" << name << "'" << dendl;
        int r = _fgetattr(fd, attrname, aset[name]);
        if (r < 0) {
          delete[] names2;
          return r;
        }
      }
    }
    name += strlen(name) + 1;
  }

  delete[] names2;
  return 0;
}

int FileStore::_fsetattrs(int fd, map<string, bufferptr> &aset)
{
  for (map<string, bufferptr>::iterator p = aset.begin();
       p != aset.end();
       ++p) {
    char n[CHAIN_XATTR_MAX_NAME_LEN];
    get_attrname(p->first.c_str(), n, CHAIN_XATTR_MAX_NAME_LEN);
    const char *val;
    if (p->second.length())
      val = p->second.c_str();
    else
      val = "";
    // ??? Why do we skip setting all the other attrs if one fails?
    int r = chain_fsetxattr(fd, n, val, p->second.length());
    if (r < 0) {
      derr << "FileStore::_setattrs: chain_setxattr returned " << r << dendl;
      return r;
    }
  }
  return 0;
}

// debug EIO injection
void FileStore::inject_data_error(const ghobject_t &oid) {
  Mutex::Locker l(read_error_lock);
  dout(10) << __func__ << ": init error on " << oid << dendl;
  data_error_set.insert(oid);
}
void FileStore::inject_mdata_error(const ghobject_t &oid) {
  Mutex::Locker l(read_error_lock);
  dout(10) << __func__ << ": init error on " << oid << dendl;
  mdata_error_set.insert(oid);
}
void FileStore::debug_obj_on_delete(const ghobject_t &oid) {
  Mutex::Locker l(read_error_lock);
  dout(10) << __func__ << ": clear error on " << oid << dendl;
  data_error_set.erase(oid);
  mdata_error_set.erase(oid);
}
bool FileStore::debug_data_eio(const ghobject_t &oid) {
  Mutex::Locker l(read_error_lock);
  if (data_error_set.count(oid)) {
    dout(10) << __func__ << ": inject error on " << oid << dendl;
    return true;
  } else {
    return false;
  }
}
bool FileStore::debug_mdata_eio(const ghobject_t &oid) {
  Mutex::Locker l(read_error_lock);
  if (mdata_error_set.count(oid)) {
    dout(10) << __func__ << ": inject error on " << oid << dendl;
    return true;
  } else {
    return false;
  }
}


// objects

int FileStore::getattr(const coll_t& _cid, const ghobject_t& oid, const char *name, bufferptr &bp)
{
  tracepoint(objectstore, getattr_enter, _cid.c_str());
  const coll_t& cid = !_need_temp_object_collection(_cid, oid) ? _cid : _cid.get_temp();
  dout(15) << "getattr " << cid << "/" << oid << " '" << name << "'" << dendl;
  FDRef fd;
  int r = lfn_open(cid, oid, false, &fd);
  if (r < 0) {
    goto out;
  }
  char n[CHAIN_XATTR_MAX_NAME_LEN];
  get_attrname(name, n, CHAIN_XATTR_MAX_NAME_LEN);
  r = _fgetattr(**fd, n, bp);
  lfn_close(fd);
  if (r == -ENODATA) {
    map<string, bufferlist> got;
    set<string> to_get;
    to_get.insert(string(name));
    Index index;
    r = get_index(cid, &index);
    if (r < 0) {
      dout(10) << __func__ << " could not get index r = " << r << dendl;
      goto out;
    }
    r = object_map->get_xattrs(oid, to_get, &got);
    if (r < 0 && r != -ENOENT) {
      dout(10) << __func__ << " get_xattrs err r =" << r << dendl;
      goto out;
    }
    if (got.empty()) {
      dout(10) << __func__ << " got.size() is 0" << dendl;
      return -ENODATA;
    }
    bp = bufferptr(got.begin()->second.c_str(),
                   got.begin()->second.length());
    r = bp.length();
  }
 out:
  dout(10) << "getattr " << cid << "/" << oid << " '" << name << "' = " << r << dendl;
  assert(!m_filestore_fail_eio || r != -EIO);
  if (cct->_conf->filestore_debug_inject_read_err &&
      debug_mdata_eio(oid)) {
    return -EIO;
  } else {
    tracepoint(objectstore, getattr_exit, r);
    return r < 0 ? r : 0;
  }
}

int FileStore::getattrs(const coll_t& _cid, const ghobject_t& oid, map<string,bufferptr>& aset)
{
  tracepoint(objectstore, getattrs_enter, _cid.c_str());
  const coll_t& cid = !_need_temp_object_collection(_cid, oid) ? _cid : _cid.get_temp();
  set<string> omap_attrs;
  map<string, bufferlist> omap_aset;
  Index index;
  dout(15) << "getattrs " << cid << "/" << oid << dendl;
  FDRef fd;
  bool spill_out = true;
  char buf[2];

  int r = lfn_open(cid, oid, false, &fd);
  if (r < 0) {
    goto out;
  }

  r = chain_fgetxattr(**fd, XATTR_SPILL_OUT_NAME, buf, sizeof(buf));
  if (r >= 0 && !strncmp(buf, XATTR_NO_SPILL_OUT, sizeof(XATTR_NO_SPILL_OUT)))
    spill_out = false;

  r = _fgetattrs(**fd, aset);
  lfn_close(fd);
  fd = FDRef(); // defensive
  if (r < 0) {
    goto out;
  }

  if (!spill_out) {
    dout(10) << __func__ << " no xattr exists in object_map r = " << r << dendl;
    goto out;
  }

  r = get_index(cid, &index);
  if (r < 0) {
    dout(10) << __func__ << " could not get index r = " << r << dendl;
    goto out;
  }
  {
    r = object_map->get_all_xattrs(oid, &omap_attrs);
    if (r < 0 && r != -ENOENT) {
      dout(10) << __func__ << " could not get omap_attrs r = " << r << dendl;
      goto out;
    }

    r = object_map->get_xattrs(oid, omap_attrs, &omap_aset);
    if (r < 0 && r != -ENOENT) {
      dout(10) << __func__ << " could not get omap_attrs r = " << r << dendl;
      goto out;
    }
    if (r == -ENOENT)
      r = 0;
  }
  assert(omap_attrs.size() == omap_aset.size());
  for (map<string, bufferlist>::iterator i = omap_aset.begin();
         i != omap_aset.end();
         ++i) {
    string key(i->first);
    aset.insert(make_pair(key,
                            bufferptr(i->second.c_str(), i->second.length())));
  }
 out:
  dout(10) << "getattrs " << cid << "/" << oid << " = " << r << dendl;
  assert(!m_filestore_fail_eio || r != -EIO);

  if (cct->_conf->filestore_debug_inject_read_err &&
      debug_mdata_eio(oid)) {
    return -EIO;
  } else {
    tracepoint(objectstore, getattrs_exit, r);
    return r;
  }
}

int FileStore::_setattrs(const coll_t& cid, const ghobject_t& oid, map<string,bufferptr>& aset,
                         const SequencerPosition &spos)
{
  map<string, bufferlist> omap_set;
  set<string> omap_remove;
  map<string, bufferptr> inline_set;
  map<string, bufferptr> inline_to_set;
  FDRef fd;
  int spill_out = -1;
  bool incomplete_inline = false;

  int r = lfn_open(cid, oid, false, &fd);
  if (r < 0) {
    goto out;
  }

  char buf[2];
  r = chain_fgetxattr(**fd, XATTR_SPILL_OUT_NAME, buf, sizeof(buf));
  if (r >= 0 && !strncmp(buf, XATTR_NO_SPILL_OUT, sizeof(XATTR_NO_SPILL_OUT)))
    spill_out = 0;
  else
    spill_out = 1;

  r = _fgetattrs(**fd, inline_set);
  incomplete_inline = (r == -E2BIG);
  assert(!m_filestore_fail_eio || r != -EIO);
  dout(15) << "setattrs " << cid << "/" << oid
           << (incomplete_inline ? " (incomplete_inline, forcing omap)" : "")
           << dendl;

  for (map<string,bufferptr>::iterator p = aset.begin();
       p != aset.end();
       ++p) {
    char n[CHAIN_XATTR_MAX_NAME_LEN];
    get_attrname(p->first.c_str(), n, CHAIN_XATTR_MAX_NAME_LEN);

    if (incomplete_inline) {
      chain_fremovexattr(**fd, n); // ignore any error
      omap_set[p->first].push_back(p->second);
      continue;
    }

    if (p->second.length() > m_filestore_max_inline_xattr_size) {
        if (inline_set.count(p->first)) {
          inline_set.erase(p->first);
          r = chain_fremovexattr(**fd, n);
          if (r < 0)
            goto out_close;
        }
        omap_set[p->first].push_back(p->second);
        continue;
    }

    if (!inline_set.count(p->first) &&
          inline_set.size() >= m_filestore_max_inline_xattrs) {
        omap_set[p->first].push_back(p->second);
        continue;
    }
    omap_remove.insert(p->first);
    inline_set.insert(*p);

    inline_to_set.insert(*p);
  }

  if (spill_out != 1 && !omap_set.empty()) {
    chain_fsetxattr(**fd, XATTR_SPILL_OUT_NAME, XATTR_SPILL_OUT,
                    sizeof(XATTR_SPILL_OUT));
  }

  r = _fsetattrs(**fd, inline_to_set);
  if (r < 0)
    goto out_close;

  if (spill_out && !omap_remove.empty()) {
    r = object_map->remove_xattrs(oid, omap_remove, &spos);
    if (r < 0 && r != -ENOENT) {
      dout(10) << __func__ << " could not remove_xattrs r = " << r << dendl;
      assert(!m_filestore_fail_eio || r != -EIO);
      goto out_close;
    } else {
      r = 0; // don't confuse the debug output
    }
  }

  if (!omap_set.empty()) {
    r = object_map->set_xattrs(oid, omap_set, &spos);
    if (r < 0) {
      dout(10) << __func__ << " could not set_xattrs r = " << r << dendl;
      assert(!m_filestore_fail_eio || r != -EIO);
      goto out_close;
    }
  }
 out_close:
  lfn_close(fd);
 out:
  dout(10) << "setattrs " << cid << "/" << oid << " = " << r << dendl;
  return r;
}


int FileStore::_rmattr(const coll_t& cid, const ghobject_t& oid, const char *name,
                       const SequencerPosition &spos)
{
  dout(15) << "rmattr " << cid << "/" << oid << " '" << name << "'" << dendl;
  FDRef fd;
  bool spill_out = true;

  int r = lfn_open(cid, oid, false, &fd);
  if (r < 0) {
    goto out;
  }

  char buf[2];
  r = chain_fgetxattr(**fd, XATTR_SPILL_OUT_NAME, buf, sizeof(buf));
  if (r >= 0 && !strncmp(buf, XATTR_NO_SPILL_OUT, sizeof(XATTR_NO_SPILL_OUT))) {
    spill_out = false;
  }

  char n[CHAIN_XATTR_MAX_NAME_LEN];
  get_attrname(name, n, CHAIN_XATTR_MAX_NAME_LEN);
  r = chain_fremovexattr(**fd, n);
  if (r == -ENODATA && spill_out) {
    Index index;
    r = get_index(cid, &index);
    if (r < 0) {
      dout(10) << __func__ << " could not get index r = " << r << dendl;
      goto out_close;
    }
    set<string> to_remove;
    to_remove.insert(string(name));
    r = object_map->remove_xattrs(oid, to_remove, &spos);
    if (r < 0 && r != -ENOENT) {
      dout(10) << __func__ << " could not remove_xattrs index r = " << r << dendl;
      assert(!m_filestore_fail_eio || r != -EIO);
      goto out_close;
    }
  }
 out_close:
  lfn_close(fd);
 out:
  dout(10) << "rmattr " << cid << "/" << oid << " '" << name << "' = " << r << dendl;
  return r;
}

int FileStore::_rmattrs(const coll_t& cid, const ghobject_t& oid,
                        const SequencerPosition &spos)
{
  dout(15) << "rmattrs " << cid << "/" << oid << dendl;

  map<string,bufferptr> aset;
  FDRef fd;
  set<string> omap_attrs;
  Index index;
  bool spill_out = true;

  int r = lfn_open(cid, oid, false, &fd);
  if (r < 0) {
    goto out;
  }

  char buf[2];
  r = chain_fgetxattr(**fd, XATTR_SPILL_OUT_NAME, buf, sizeof(buf));
  if (r >= 0 && !strncmp(buf, XATTR_NO_SPILL_OUT, sizeof(XATTR_NO_SPILL_OUT))) {
    spill_out = false;
  }

  r = _fgetattrs(**fd, aset);
  if (r >= 0) {
    for (map<string,bufferptr>::iterator p = aset.begin(); p != aset.end(); ++p) {
      char n[CHAIN_XATTR_MAX_NAME_LEN];
      get_attrname(p->first.c_str(), n, CHAIN_XATTR_MAX_NAME_LEN);
      r = chain_fremovexattr(**fd, n);
      if (r < 0) {
        dout(10) << __func__ << " could not remove xattr r = " << r << dendl;
        goto out_close;
      }
    }
  }

  if (!spill_out) {
    dout(10) << __func__ << " no xattr exists in object_map r = " << r << dendl;
    goto out_close;
  }

  r = get_index(cid, &index);
  if (r < 0) {
    dout(10) << __func__ << " could not get index r = " << r << dendl;
    goto out_close;
  }
  {
    r = object_map->get_all_xattrs(oid, &omap_attrs);
    if (r < 0 && r != -ENOENT) {
      dout(10) << __func__ << " could not get omap_attrs r = " << r << dendl;
      assert(!m_filestore_fail_eio || r != -EIO);
      goto out_close;
    }
    r = object_map->remove_xattrs(oid, omap_attrs, &spos);
    if (r < 0 && r != -ENOENT) {
      dout(10) << __func__ << " could not remove omap_attrs r = " << r << dendl;
      goto out_close;
    }
    if (r == -ENOENT)
      r = 0;
    chain_fsetxattr(**fd, XATTR_SPILL_OUT_NAME, XATTR_NO_SPILL_OUT,
                  sizeof(XATTR_NO_SPILL_OUT));
  }

 out_close:
  lfn_close(fd);
 out:
  dout(10) << "rmattrs " << cid << "/" << oid << " = " << r << dendl;
  return r;
}




int FileStore::_collection_remove_recursive(const coll_t &cid,
                                            const SequencerPosition &spos)
{
  struct stat st;
  int r = collection_stat(cid, &st);
  if (r < 0) {
    if (r == -ENOENT)
      return 0;
    return r;
  }

  vector<ghobject_t> objects;
  ghobject_t max;
  while (!max.is_max()) {
    r = collection_list(cid, max, ghobject_t::get_max(),
                        300, &objects, &max);
    if (r < 0)
      return r;
    for (vector<ghobject_t>::iterator i = objects.begin();
         i != objects.end();
         ++i) {
      assert(_check_replay_guard(cid, *i, spos));
      r = _remove(cid, *i, spos);
      if (r < 0)
        return r;
    }
    objects.clear();
  }
  return _destroy_collection(cid);
}

// --------------------------
// collections

int FileStore::list_collections(vector<coll_t>& ls)
{
  return list_collections(ls, false);
}

int FileStore::list_collections(vector<coll_t>& ls, bool include_temp)
{
  tracepoint(objectstore, list_collections_enter);
  dout(10) << "list_collections" << dendl;

  char fn[PATH_MAX];
  snprintf(fn, sizeof(fn), "%s/current", basedir.c_str());

  int r = 0;
  DIR *dir = ::opendir(fn);
  if (!dir) {
    r = -errno;
    derr << "tried opening directory " << fn << ": " << cpp_strerror(-r) << dendl;
    assert(!m_filestore_fail_eio || r != -EIO);
    return r;
  }

  struct dirent *de = nullptr;
  while ((de = ::readdir(dir))) {
    if (de->d_type == DT_UNKNOWN) {
      // d_type not supported (non-ext[234], btrfs), must stat
      struct stat sb;
      char filename[PATH_MAX];
      snprintf(filename, sizeof(filename), "%s/%s", fn, de->d_name);

      r = ::stat(filename, &sb);
      if (r < 0) {
        r = -errno;
        derr << "stat on " << filename << ": " << cpp_strerror(-r) << dendl;
        assert(!m_filestore_fail_eio || r != -EIO);
        break;
      }
      if (!S_ISDIR(sb.st_mode)) {
        continue;
      }
    } else if (de->d_type != DT_DIR) {
      continue;
    }
    if (strcmp(de->d_name, "omap") == 0) {
      continue;
    }
    if (de->d_name[0] == '.' &&
        (de->d_name[1] == '\0' ||
         (de->d_name[1] == '.' &&
          de->d_name[2] == '\0')))
      continue;
    coll_t cid;
    if (!cid.parse(de->d_name)) {
      derr << "ignoring invalid collection '" << de->d_name << "'" << dendl;
      continue;
    }
    if (!cid.is_temp() || include_temp)
      ls.push_back(cid);
  }

  if (r > 0) {
    derr << "trying readdir " << fn << ": " << cpp_strerror(r) << dendl;
    r = -r;
  }

  ::closedir(dir);
  assert(!m_filestore_fail_eio || r != -EIO);
  tracepoint(objectstore, list_collections_exit, r);
  return r;
}

int FileStore::collection_stat(const coll_t& c, struct stat *st)
{
  tracepoint(objectstore, collection_stat_enter, c.c_str());
  char fn[PATH_MAX];
  get_cdir(c, fn, sizeof(fn));
  dout(15) << "collection_stat " << fn << dendl;
  int r = ::stat(fn, st);
  if (r < 0)
    r = -errno;
  dout(10) << "collection_stat " << fn << " = " << r << dendl;
  assert(!m_filestore_fail_eio || r != -EIO);
  tracepoint(objectstore, collection_stat_exit, r);
  return r;
}

bool FileStore::collection_exists(const coll_t& c)
{
  tracepoint(objectstore, collection_exists_enter, c.c_str());
  struct stat st;
  bool ret = collection_stat(c, &st) == 0;
  tracepoint(objectstore, collection_exists_exit, ret);
  return ret;
}

int FileStore::collection_empty(const coll_t& c, bool *empty)
{
  tracepoint(objectstore, collection_empty_enter, c.c_str());
  dout(15) << "collection_empty " << c << dendl;
  Index index;
  int r = get_index(c, &index);
  if (r < 0) {
    derr << __func__ << " get_index returned: " << cpp_strerror(r)
         << dendl;
    return r;
  }

  assert(NULL != index.index);
  RWLock::RLocker l((index.index)->access_lock);

  vector<ghobject_t> ls;
  r = index->collection_list_partial(ghobject_t(), ghobject_t::get_max(),
                                     1, &ls, NULL);
  if (r < 0) {
    derr << __func__ << " collection_list_partial returned: "
         << cpp_strerror(r) << dendl;
    assert(!m_filestore_fail_eio || r != -EIO);
    return r;
  }
  *empty = ls.empty();
  tracepoint(objectstore, collection_empty_exit, *empty);
  return 0;
}

int FileStore::_collection_set_bits(const coll_t& c, int bits)
{
  char fn[PATH_MAX];
  get_cdir(c, fn, sizeof(fn));
  dout(10) << "collection_set_bits " << fn << " " << bits << dendl;
  char n[PATH_MAX];
  int r;
  int32_t v = bits;
  int fd = ::open(fn, O_RDONLY);
  if (fd < 0) {
    r = -errno;
    goto out;
  }
  get_attrname("bits", n, PATH_MAX);
  r = chain_fsetxattr(fd, n, (char*)&v, sizeof(v));
  VOID_TEMP_FAILURE_RETRY(::close(fd));
 out:
  dout(10) << "collection_setattr " << fn << " " << bits << " = " << r << dendl;
  return r;
}

int FileStore::collection_bits(const coll_t& c)
{
  char fn[PATH_MAX];
  get_cdir(c, fn, sizeof(fn));
  dout(15) << "collection_bits " << fn << dendl;
  int r;
  char n[PATH_MAX];
  int32_t bits;
  int fd = ::open(fn, O_RDONLY);
  if (fd < 0) {
    bits = r = -errno;
    goto out;
  }
  get_attrname("bits", n, PATH_MAX);
  r = chain_fgetxattr(fd, n, (char*)&bits, sizeof(bits));
  VOID_TEMP_FAILURE_RETRY(::close(fd));
  if (r < 0) {
    bits = r;
    goto out;
  }
 out:
  dout(10) << "collection_bits " << fn << " = " << bits << dendl;
  return bits;
}

int FileStore::collection_list(const coll_t& c,
                               const ghobject_t& orig_start,
                               const ghobject_t& end,
                               int max,
                               vector<ghobject_t> *ls, ghobject_t *next)
{
  ghobject_t start = orig_start;
  if (start.is_max())
    return 0;

  ghobject_t temp_next;
  if (!next)
    next = &temp_next;
  // figure out the pool id.  we need this in order to generate a
  // meaningful 'next' value.
  int64_t pool = -1;
  shard_id_t shard;
  {
    spg_t pgid;
    if (c.is_temp(&pgid)) {
      pool = -2 - pgid.pool();
      shard = pgid.shard;
    } else if (c.is_pg(&pgid)) {
      pool = pgid.pool();
      shard = pgid.shard;
    } else if (c.is_meta()) {
      pool = -1;
      shard = shard_id_t::NO_SHARD;
    } else {
      // hrm, the caller is test code!  we should get kill it off.  for now,
      // tolerate it.
      pool = 0;
      shard = shard_id_t::NO_SHARD;
    }
    dout(20) << __func__ << " pool is " << pool << " shard is " << shard
             << " pgid " << pgid << dendl;
  }
  ghobject_t sep;
  sep.hobj.pool = -1;
  sep.set_shard(shard);
  if (!c.is_temp() && !c.is_meta()) {
    if (start < sep) {
      dout(10) << __func__ << " first checking temp pool" << dendl;
      coll_t temp = c.get_temp();
      int r = collection_list(temp, start, end, max, ls, next);
      if (r < 0)
        return r;
      if (*next != ghobject_t::get_max())
        return r;
      start = sep;
      dout(10) << __func__ << " fall through to non-temp collection, start "
               << start << dendl;
    } else {
      dout(10) << __func__ << " start " << start << " >= sep " << sep << dendl;
    }
  }

  Index index;
  int r = get_index(c, &index);
  if (r < 0)
    return r;

  assert(NULL != index.index);
  RWLock::RLocker l((index.index)->access_lock);

  r = index->collection_list_partial(start, end, max, ls, next);

  if (r < 0) {
    assert(!m_filestore_fail_eio || r != -EIO);
    return r;
  }
  dout(20) << "objects: " << *ls << dendl;

  // HashIndex doesn't know the pool when constructing a 'next' value
  if (next && !next->is_max()) {
    next->hobj.pool = pool;
    next->set_shard(shard);
    dout(20) << "  next " << *next << dendl;
  }

  return 0;
}

int FileStore::omap_get(const coll_t& _c, const ghobject_t &hoid,
                        bufferlist *header,
                        map<string, bufferlist> *out)
{
  tracepoint(objectstore, omap_get_enter, _c.c_str());
  const coll_t& c = !_need_temp_object_collection(_c, hoid) ? _c : _c.get_temp();
  dout(15) << __func__ << " " << c << "/" << hoid << dendl;
  Index index;
  int r = get_index(c, &index);
  if (r < 0)
    return r;
  {
    assert(NULL != index.index);
    RWLock::RLocker l((index.index)->access_lock);
    r = lfn_find(hoid, index);
    if (r < 0)
      return r;
  }
  r = object_map->get(hoid, header, out);
  if (r < 0 && r != -ENOENT) {
    assert(!m_filestore_fail_eio || r != -EIO);
    return r;
  }
  tracepoint(objectstore, omap_get_exit, 0);
  return 0;
}

int FileStore::omap_get_header(
  const coll_t& _c,
  const ghobject_t &hoid,
  bufferlist *bl,
  bool allow_eio)
{
  tracepoint(objectstore, omap_get_header_enter, _c.c_str());
  const coll_t& c = !_need_temp_object_collection(_c, hoid) ? _c : _c.get_temp();
  dout(15) << __func__ << " " << c << "/" << hoid << dendl;
  Index index;
  int r = get_index(c, &index);
  if (r < 0)
    return r;
  {
    assert(NULL != index.index);
    RWLock::RLocker l((index.index)->access_lock);
    r = lfn_find(hoid, index);
    if (r < 0)
      return r;
  }
  r = object_map->get_header(hoid, bl);
  if (r < 0 && r != -ENOENT) {
    assert(allow_eio || !m_filestore_fail_eio || r != -EIO);
    return r;
  }
  tracepoint(objectstore, omap_get_header_exit, 0);
  return 0;
}

int FileStore::omap_get_keys(const coll_t& _c, const ghobject_t &hoid, set<string> *keys)
{
  tracepoint(objectstore, omap_get_keys_enter, _c.c_str());
  const coll_t& c = !_need_temp_object_collection(_c, hoid) ? _c : _c.get_temp();
  dout(15) << __func__ << " " << c << "/" << hoid << dendl;
  Index index;
  int r = get_index(c, &index);
  if (r < 0)
    return r;
  {
    assert(NULL != index.index);
    RWLock::RLocker l((index.index)->access_lock);
    r = lfn_find(hoid, index);
    if (r < 0)
      return r;
  }
  r = object_map->get_keys(hoid, keys);
  if (r < 0 && r != -ENOENT) {
    assert(!m_filestore_fail_eio || r != -EIO);
    return r;
  }
  tracepoint(objectstore, omap_get_keys_exit, 0);
  return 0;
}

int FileStore::omap_get_values(const coll_t& _c, const ghobject_t &hoid,
                               const set<string> &keys,
                               map<string, bufferlist> *out)
{
  tracepoint(objectstore, omap_get_values_enter, _c.c_str());
  const coll_t& c = !_need_temp_object_collection(_c, hoid) ? _c : _c.get_temp();
  dout(15) << __func__ << " " << c << "/" << hoid << dendl;
  Index index;
  const char *where = "()";
  int r = get_index(c, &index);
  if (r < 0) {
    where = " (get_index)";
    goto out;
  }
  {
    assert(NULL != index.index);
    RWLock::RLocker l((index.index)->access_lock);
    r = lfn_find(hoid, index);
    if (r < 0) {
      where = " (lfn_find)";
      goto out;
    }
  }
  r = object_map->get_values(hoid, keys, out);
  if (r < 0 && r != -ENOENT) {
    assert(!m_filestore_fail_eio || r != -EIO);
    where = " (get_values)";
    goto out;
  }
  r = 0;
 out:
  tracepoint(objectstore, omap_get_values_exit, r);
  dout(15) << __func__ << " " << c << "/" << hoid << " = " << r
           << where << dendl;
  return r;
}

int FileStore::omap_check_keys(const coll_t& _c, const ghobject_t &hoid,
                               const set<string> &keys,
                               set<string> *out)
{
  tracepoint(objectstore, omap_check_keys_enter, _c.c_str());
  const coll_t& c = !_need_temp_object_collection(_c, hoid) ? _c : _c.get_temp();
  dout(15) << __func__ << " " << c << "/" << hoid << dendl;

  Index index;
  int r = get_index(c, &index);
  if (r < 0)
    return r;
  {
    assert(NULL != index.index);
    RWLock::RLocker l((index.index)->access_lock);
    r = lfn_find(hoid, index);
    if (r < 0)
      return r;
  }
  r = object_map->check_keys(hoid, keys, out);
  if (r < 0 && r != -ENOENT) {
    assert(!m_filestore_fail_eio || r != -EIO);
    return r;
  }
  tracepoint(objectstore, omap_check_keys_exit, 0);
  return 0;
}

ObjectMap::ObjectMapIterator FileStore::get_omap_iterator(const coll_t& _c,
                                                          const ghobject_t &hoid)
{
  tracepoint(objectstore, get_omap_iterator, _c.c_str());
  const coll_t& c = !_need_temp_object_collection(_c, hoid) ? _c : _c.get_temp();
  dout(15) << __func__ << " " << c << "/" << hoid << dendl;
  Index index;
  int r = get_index(c, &index);
  if (r < 0) {
    dout(10) << __func__ << " " << c << "/" << hoid << " = 0 "
             << "(get_index failed with " << cpp_strerror(r) << ")" << dendl;
    return ObjectMap::ObjectMapIterator();
  }
  {
    assert(NULL != index.index);
    RWLock::RLocker l((index.index)->access_lock);
    r = lfn_find(hoid, index);
    if (r < 0) {
      dout(10) << __func__ << " " << c << "/" << hoid << " = 0 "
               << "(lfn_find failed with " << cpp_strerror(r) << ")" << dendl;
      return ObjectMap::ObjectMapIterator();
    }
  }
  return object_map->get_iterator(hoid);
}

int FileStore::_collection_hint_expected_num_objs(const coll_t& c, uint32_t pg_num,
    uint64_t expected_num_objs,
    const SequencerPosition &spos)
{
  dout(15) << __func__ << " collection: " << c << " pg number: "
     << pg_num << " expected number of objects: " << expected_num_objs << dendl;

  bool empty;
  int ret = collection_empty(c, &empty);
  if (ret < 0)
    return ret;
  if (!empty && !replaying) {
    dout(0) << "Failed to give an expected number of objects hint to collection : "
      << c << ", only empty collection can take such type of hint. " << dendl;
    return 0;
  }

  Index index;
  ret = get_index(c, &index);
  if (ret < 0)
    return ret;
  // Pre-hash the collection
  ret = index->pre_hash_collection(pg_num, expected_num_objs);
  dout(10) << "pre_hash_collection " << c << " = " << ret << dendl;
  if (ret < 0)
    return ret;
  _set_replay_guard(c, spos);

  return 0;
}

int FileStore::_create_collection(
  const coll_t& c,
  int bits,
  const SequencerPosition &spos)
{
  char fn[PATH_MAX];
  get_cdir(c, fn, sizeof(fn));
  dout(15) << "create_collection " << fn << dendl;
  int r = ::mkdir(fn, 0755);
  if (r < 0)
    r = -errno;
  if (r == -EEXIST && replaying)
    r = 0;
  dout(10) << "create_collection " << fn << " = " << r << dendl;

  if (r < 0)
    return r;
  r = init_index(c);
  if (r < 0)
    return r;
  r = _collection_set_bits(c, bits);
  if (r < 0)
    return r;
  // create parallel temp collection, too
  if (!c.is_meta() && !c.is_temp()) {
    coll_t temp = c.get_temp();
    r = _create_collection(temp, 0, spos);
    if (r < 0)
      return r;
  }

  _set_replay_guard(c, spos);
  return 0;
}

int FileStore::_destroy_collection(const coll_t& c)
{
  int r = 0;
  char fn[PATH_MAX];
  get_cdir(c, fn, sizeof(fn));
  dout(15) << "_destroy_collection " << fn << dendl;
  {
    Index from;
    r = get_index(c, &from);
    if (r < 0)
      goto out;
    assert(NULL != from.index);
    RWLock::WLocker l((from.index)->access_lock);

    r = from->prep_delete();
    if (r < 0)
      goto out;
  }
  r = ::rmdir(fn);
  if (r < 0) {
    r = -errno;
    goto out;
  }

 out:
  // destroy parallel temp collection, too
  if (!c.is_meta() && !c.is_temp()) {
    coll_t temp = c.get_temp();
    int r2 = _destroy_collection(temp);
    if (r2 < 0) {
      r = r2;
      goto out_final;
    }
  }

 out_final:
  dout(10) << "_destroy_collection " << fn << " = " << r << dendl;
  return r;
}


int FileStore::_collection_add(const coll_t& c, const coll_t& oldcid, const ghobject_t& o,
                               const SequencerPosition& spos)
{
  dout(15) << "collection_add " << c << "/" << o << " from " << oldcid << "/" << o << dendl;

  int dstcmp = _check_replay_guard(c, o, spos);
  if (dstcmp < 0)
    return 0;

  // check the src name too; it might have a newer guard, and we don't
  // want to clobber it
  int srccmp = _check_replay_guard(oldcid, o, spos);
  if (srccmp < 0)
    return 0;

  // open guard on object so we don't any previous operations on the
  // new name that will modify the source inode.
  FDRef fd;
  int r = lfn_open(oldcid, o, 0, &fd);
  if (r < 0) {
    // the source collection/object does not exist. If we are replaying, we
    // should be safe, so just return 0 and move on.
    assert(replaying);
    dout(10) << "collection_add " << c << "/" << o << " from "
             << oldcid << "/" << o << " (dne, continue replay) " << dendl;
    return 0;
  }
  if (dstcmp > 0) {      // if dstcmp == 0 the guard already says "in-progress"
    _set_replay_guard(**fd, spos, &o, true);
  }

  r = lfn_link(oldcid, c, o, o);
  if (replaying && !backend->can_checkpoint() &&
      r == -EEXIST)    // crashed between link() and set_replay_guard()
    r = 0;

  _inject_failure();

  // close guard on object so we don't do this again
  if (r == 0) {
    _close_replay_guard(**fd, spos);
  }
  lfn_close(fd);

  dout(10) << "collection_add " << c << "/" << o << " from " << oldcid << "/" << o << " = " << r << dendl;
  return r;
}

int FileStore::_collection_move_rename(const coll_t& oldcid, const ghobject_t& oldoid,
                                       coll_t c, const ghobject_t& o,
                                       const SequencerPosition& spos,
                                       bool allow_enoent)
{
  dout(15) << __func__ << " " << c << "/" << o << " from " << oldcid << "/" << oldoid << dendl;
  int r = 0;
  int dstcmp, srccmp;

  if (replaying) {
    /* If the destination collection doesn't exist during replay,
     * we need to delete the src object and continue on
     */
    if (!collection_exists(c))
      goto out_rm_src;
  }

  dstcmp = _check_replay_guard(c, o, spos);
  if (dstcmp < 0)
    goto out_rm_src;

  // check the src name too; it might have a newer guard, and we don't
  // want to clobber it
  srccmp = _check_replay_guard(oldcid, oldoid, spos);
  if (srccmp < 0)
    return 0;

  {
    // open guard on object so we don't any previous operations on the
    // new name that will modify the source inode.
    FDRef fd;
    r = lfn_open(oldcid, oldoid, 0, &fd);
    if (r < 0) {
      // the source collection/object does not exist. If we are replaying, we
      // should be safe, so just return 0 and move on.
      if (replaying) {
        dout(10) << __func__ << " " << c << "/" << o << " from "
                 << oldcid << "/" << oldoid << " (dne, continue replay) " << dendl;
      } else if (allow_enoent) {
        dout(10) << __func__ << " " << c << "/" << o << " from "
                 << oldcid << "/" << oldoid << " (dne, ignoring enoent)"
                 << dendl;
      } else {
        assert(0 == "ERROR: source must exist");
      }

      if (!replaying) {
        return 0;
      }
      if (allow_enoent && dstcmp > 0) { // if dstcmp == 0, try_rename was started.
        return 0;
      }

      r = 0; // don't know if object_map was cloned
    } else {
      if (dstcmp > 0) { // if dstcmp == 0 the guard already says "in-progress"
        _set_replay_guard(**fd, spos, &o, true);
      }

      r = lfn_link(oldcid, c, oldoid, o);
      if (replaying && !backend->can_checkpoint() &&
          r == -EEXIST)    // crashed between link() and set_replay_guard()
        r = 0;

      lfn_close(fd);
      fd = FDRef();

      _inject_failure();
    }

    if (r == 0) {
      // the name changed; link the omap content
      r = object_map->rename(oldoid, o, &spos);
      if (r == -ENOENT)
        r = 0;
    }

    _inject_failure();

    if (r == 0)
      r = lfn_unlink(oldcid, oldoid, spos, true);

    if (r == 0)
      r = lfn_open(c, o, 0, &fd);

    // close guard on object so we don't do this again
    if (r == 0) {
      _close_replay_guard(**fd, spos, &o);
      lfn_close(fd);
    }
  }

  dout(10) << __func__ << " " << c << "/" << o << " from " << oldcid << "/" << oldoid
           << " = " << r << dendl;
  return r;

 out_rm_src:
  // remove source
  if (_check_replay_guard(oldcid, oldoid, spos) > 0) {
    r = lfn_unlink(oldcid, oldoid, spos, true);
  }

  dout(10) << __func__ << " " << c << "/" << o << " from " << oldcid << "/" << oldoid
           << " = " << r << dendl;
  return r;
}

void FileStore::_inject_failure()
{
  if (m_filestore_kill_at.read()) {
    int final = m_filestore_kill_at.dec();
    dout(5) << "_inject_failure " << (final+1) << " -> " << final << dendl;
    if (final == 0) {
      derr << "_inject_failure KILLING" << dendl;
      cct->_log->flush();
      _exit(1);
    }
  }
}

int FileStore::_omap_clear(const coll_t& cid, const ghobject_t &hoid,
                           const SequencerPosition &spos) {
  dout(15) << __func__ << " " << cid << "/" << hoid << dendl;
  Index index;
  int r = get_index(cid, &index);
  if (r < 0)
    return r;
  {
    assert(NULL != index.index);
    RWLock::RLocker l((index.index)->access_lock);
    r = lfn_find(hoid, index);
    if (r < 0)
      return r;
  }
  r = object_map->clear_keys_header(hoid, &spos);
  if (r < 0 && r != -ENOENT)
    return r;
  return 0;
}

int FileStore::_omap_setkeys(const coll_t& cid, const ghobject_t &hoid,
                             const map<string, bufferlist> &aset,
                             const SequencerPosition &spos) {
  dout(15) << __func__ << " " << cid << "/" << hoid << dendl;
  Index index;
  int r;
  //treat pgmeta as a logical object, skip to check exist
  if (hoid.is_pgmeta())
    goto skip;

  r = get_index(cid, &index);
  if (r < 0) {
    dout(20) << __func__ << " get_index got " << cpp_strerror(r) << dendl;
    return r;
  }
  {
    assert(NULL != index.index);
    RWLock::RLocker l((index.index)->access_lock);
    r = lfn_find(hoid, index);
    if (r < 0) {
      dout(20) << __func__ << " lfn_find got " << cpp_strerror(r) << dendl;
      return r;
    }
  }
skip:
  if (g_conf->subsys.should_gather(ceph_subsys_filestore, 20)) {
    for (auto& p : aset) {
      dout(20) << __func__ << "  set " << p.first << dendl;
    }
  }
  r = object_map->set_keys(hoid, aset, &spos);
  dout(20) << __func__ << " " << cid << "/" << hoid << " = " << r << dendl;
  return r;
}

int FileStore::_omap_rmkeys(const coll_t& cid, const ghobject_t &hoid,
                            const set<string> &keys,
                            const SequencerPosition &spos) {
  dout(15) << __func__ << " " << cid << "/" << hoid << dendl;
  Index index;
  int r;
  //treat pgmeta as a logical object, skip to check exist
  if (hoid.is_pgmeta())
    goto skip;

  r = get_index(cid, &index);
  if (r < 0)
    return r;
  {
    assert(NULL != index.index);
    RWLock::RLocker l((index.index)->access_lock);
    r = lfn_find(hoid, index);
    if (r < 0)
      return r;
  }
skip:
  r = object_map->rm_keys(hoid, keys, &spos);
  if (r < 0 && r != -ENOENT)
    return r;
  return 0;
}

int FileStore::_omap_rmkeyrange(const coll_t& cid, const ghobject_t &hoid,
                                const string& first, const string& last,
                                const SequencerPosition &spos) {
  dout(15) << __func__ << " " << cid << "/" << hoid << " [" << first << "," << last << "]" << dendl;
  set<string> keys;
  {
    ObjectMap::ObjectMapIterator iter = get_omap_iterator(cid, hoid);
    if (!iter)
      return -ENOENT;
    for (iter->lower_bound(first); iter->valid() && iter->key() < last;
         iter->next()) {
      keys.insert(iter->key());
    }
  }
  return _omap_rmkeys(cid, hoid, keys, spos);
}

int FileStore::_omap_setheader(const coll_t& cid, const ghobject_t &hoid,
                               const bufferlist &bl,
                               const SequencerPosition &spos)
{
  dout(15) << __func__ << " " << cid << "/" << hoid << dendl;
  Index index;
  int r = get_index(cid, &index);
  if (r < 0)
    return r;
  {
    assert(NULL != index.index);
    RWLock::RLocker l((index.index)->access_lock);
    r = lfn_find(hoid, index);
    if (r < 0)
      return r;
  }
  return object_map->set_header(hoid, bl, &spos);
}

int FileStore::_split_collection(const coll_t& cid,
                                 uint32_t bits,
                                 uint32_t rem,
                                 coll_t dest,
                                 const SequencerPosition &spos)
{
  int r;
  {
    dout(15) << __func__ << " " << cid << " bits: " << bits << dendl;
    if (!collection_exists(cid)) {
      dout(2) << __func__ << ": " << cid << " DNE" << dendl;
      assert(replaying);
      return 0;
    }
    if (!collection_exists(dest)) {
      dout(2) << __func__ << ": " << dest << " DNE" << dendl;
      assert(replaying);
      return 0;
    }

    int dstcmp = _check_replay_guard(dest, spos);
    if (dstcmp < 0)
      return 0;

    int srccmp = _check_replay_guard(cid, spos);
    if (srccmp < 0)
      return 0;

    _set_global_replay_guard(cid, spos);
    _set_replay_guard(cid, spos, true);
    _set_replay_guard(dest, spos, true);

    Index from;
    r = get_index(cid, &from);

    Index to;
    if (!r)
      r = get_index(dest, &to);

    if (!r) {
      assert(NULL != from.index);
      RWLock::WLocker l1((from.index)->access_lock);

      assert(NULL != to.index);
      RWLock::WLocker l2((to.index)->access_lock);

      r = from->split(rem, bits, to.index);
    }

    _close_replay_guard(cid, spos);
    _close_replay_guard(dest, spos);
  }
  _collection_set_bits(cid, bits);
  if (!r && cct->_conf->filestore_debug_verify_split) {
    vector<ghobject_t> objects;
    ghobject_t next;
    while (1) {
      collection_list(
        cid,
        next, ghobject_t::get_max(),
        get_ideal_list_max(),
        &objects,
        &next);
      if (objects.empty())
        break;
      for (vector<ghobject_t>::iterator i = objects.begin();
           i != objects.end();
           ++i) {
        dout(20) << __func__ << ": " << *i << " still in source "
                 << cid << dendl;
        assert(!i->match(bits, rem));
      }
      objects.clear();
    }
    next = ghobject_t();
    while (1) {
      collection_list(
        dest,
        next, ghobject_t::get_max(),
        get_ideal_list_max(),
        &objects,
        &next);
      if (objects.empty())
        break;
      for (vector<ghobject_t>::iterator i = objects.begin();
           i != objects.end();
           ++i) {
        dout(20) << __func__ << ": " << *i << " now in dest "
                 << *i << dendl;
        assert(i->match(bits, rem));
      }
      objects.clear();
    }
  }
  return r;
}

int FileStore::_set_alloc_hint(const coll_t& cid, const ghobject_t& oid,
                               uint64_t expected_object_size,
                               uint64_t expected_write_size)
{
  dout(15) << "set_alloc_hint " << cid << "/" << oid << " object_size " << expected_object_size << " write_size " << expected_write_size << dendl;

  FDRef fd;
  int ret = 0;

  if (expected_object_size == 0 || expected_write_size == 0)
    goto out;

  ret = lfn_open(cid, oid, false, &fd);
  if (ret < 0)
    goto out;

  {
    // TODO: a more elaborate hint calculation
    uint64_t hint = MIN(expected_write_size, m_filestore_max_alloc_hint_size);

    ret = backend->set_alloc_hint(**fd, hint);
    dout(20) << "set_alloc_hint hint " << hint << " ret " << ret << dendl;
  }

  lfn_close(fd);
out:
  dout(10) << "set_alloc_hint " << cid << "/" << oid << " object_size " << expected_object_size << " write_size " << expected_write_size << " = " << ret << dendl;
  assert(!m_filestore_fail_eio || ret != -EIO);
  return ret;
}

const char** FileStore::get_tracked_conf_keys() const
{
  static const char* KEYS[] = {
    "filestore_max_inline_xattr_size",
    "filestore_max_inline_xattr_size_xfs",
    "filestore_max_inline_xattr_size_btrfs",
    "filestore_max_inline_xattr_size_other",
    "filestore_max_inline_xattrs",
    "filestore_max_inline_xattrs_xfs",
    "filestore_max_inline_xattrs_btrfs",
    "filestore_max_inline_xattrs_other",
    "filestore_max_xattr_value_size",
    "filestore_max_xattr_value_size_xfs",
    "filestore_max_xattr_value_size_btrfs",
    "filestore_max_xattr_value_size_other",
    "filestore_min_sync_interval",
    "filestore_max_sync_interval",
    "filestore_queue_max_ops",
    "filestore_queue_max_bytes",
    "filestore_expected_throughput_bytes",
    "filestore_expected_throughput_ops",
    "filestore_queue_low_threshhold",
    "filestore_queue_high_threshhold",
    "filestore_queue_high_delay_multiple",
    "filestore_queue_max_delay_multiple",
    "filestore_commit_timeout",
    "filestore_dump_file",
    "filestore_kill_at",
    "filestore_fail_eio",
    "filestore_fadvise",
    "filestore_sloppy_crc",
    "filestore_sloppy_crc_block_size",
    "filestore_max_alloc_hint_size",
    NULL
  };
  return KEYS;
}

void FileStore::handle_conf_change(const struct md_config_t *conf,
                          const std::set <std::string> &changed)
{
  if (changed.count("filestore_max_inline_xattr_size") ||
      changed.count("filestore_max_inline_xattr_size_xfs") ||
      changed.count("filestore_max_inline_xattr_size_btrfs") ||
      changed.count("filestore_max_inline_xattr_size_other") ||
      changed.count("filestore_max_inline_xattrs") ||
      changed.count("filestore_max_inline_xattrs_xfs") ||
      changed.count("filestore_max_inline_xattrs_btrfs") ||
      changed.count("filestore_max_inline_xattrs_other") ||
      changed.count("filestore_max_xattr_value_size") ||
      changed.count("filestore_max_xattr_value_size_xfs") ||
      changed.count("filestore_max_xattr_value_size_btrfs") ||
      changed.count("filestore_max_xattr_value_size_other")) {
    if (backend) {
      Mutex::Locker l(lock);
      set_xattr_limits_via_conf();
    }
  }

  if (changed.count("filestore_queue_max_bytes") ||
      changed.count("filestore_queue_max_ops") ||
      changed.count("filestore_expected_throughput_bytes") ||
      changed.count("filestore_expected_throughput_ops") ||
      changed.count("filestore_queue_low_threshhold") ||
      changed.count("filestore_queue_high_threshhold") ||
      changed.count("filestore_queue_high_delay_multiple") ||
      changed.count("filestore_queue_max_delay_multiple")) {
    Mutex::Locker l(lock);
    set_throttle_params();
  }

  if (changed.count("filestore_min_sync_interval") ||
      changed.count("filestore_max_sync_interval") ||
      changed.count("filestore_kill_at") ||
      changed.count("filestore_fail_eio") ||
      changed.count("filestore_sloppy_crc") ||
      changed.count("filestore_sloppy_crc_block_size") ||
      changed.count("filestore_max_alloc_hint_size") ||
      changed.count("filestore_fadvise")) {
    Mutex::Locker l(lock);
    m_filestore_min_sync_interval = conf->filestore_min_sync_interval;
    m_filestore_max_sync_interval = conf->filestore_max_sync_interval;
    m_filestore_kill_at.set(conf->filestore_kill_at);
    m_filestore_fail_eio = conf->filestore_fail_eio;
    m_filestore_fadvise = conf->filestore_fadvise;
    m_filestore_sloppy_crc = conf->filestore_sloppy_crc;
    m_filestore_sloppy_crc_block_size = conf->filestore_sloppy_crc_block_size;
    m_filestore_max_alloc_hint_size = conf->filestore_max_alloc_hint_size;
  }
  if (changed.count("filestore_commit_timeout")) {
    Mutex::Locker l(sync_entry_timeo_lock);
    m_filestore_commit_timeout = conf->filestore_commit_timeout;
  }
  if (changed.count("filestore_dump_file")) {
    if (conf->filestore_dump_file.length() &&
        conf->filestore_dump_file != "-") {
      dump_start(conf->filestore_dump_file);
    } else {
      dump_stop();
    }
  }
}

int FileStore::set_throttle_params()
{
  stringstream ss;
  bool valid = throttle_bytes.set_params(
    cct->_conf->filestore_queue_low_threshhold,
    cct->_conf->filestore_queue_high_threshhold,
    cct->_conf->filestore_expected_throughput_bytes,
    cct->_conf->filestore_queue_high_delay_multiple,
    cct->_conf->filestore_queue_max_delay_multiple,
    cct->_conf->filestore_queue_max_bytes,
    &ss);

  valid &= throttle_ops.set_params(
    cct->_conf->filestore_queue_low_threshhold,
    cct->_conf->filestore_queue_high_threshhold,
    cct->_conf->filestore_expected_throughput_ops,
    cct->_conf->filestore_queue_high_delay_multiple,
    cct->_conf->filestore_queue_max_delay_multiple,
    cct->_conf->filestore_queue_max_ops,
    &ss);

  logger->set(l_filestore_op_queue_max_ops, throttle_ops.get_max());
  logger->set(l_filestore_op_queue_max_bytes, throttle_bytes.get_max());

  if (!valid) {
    derr << "tried to set invalid params: "
         << ss.str()
         << dendl;
  }
  return valid ? 0 : -EINVAL;
}

void FileStore::dump_start(const std::string& file)
{
  dout(10) << "dump_start " << file << dendl;
  if (m_filestore_do_dump) {
    dump_stop();
  }
  m_filestore_dump_fmt.reset();
  m_filestore_dump_fmt.open_array_section("dump");
  m_filestore_dump.open(file.c_str());
  m_filestore_do_dump = true;
}

void FileStore::dump_stop()
{
  dout(10) << "dump_stop" << dendl;
  m_filestore_do_dump = false;
  if (m_filestore_dump.is_open()) {
    m_filestore_dump_fmt.close_section();
    m_filestore_dump_fmt.flush(m_filestore_dump);
    m_filestore_dump.flush();
    m_filestore_dump.close();
  }
}

void FileStore::dump_transactions(vector<ObjectStore::Transaction>& ls, uint64_t seq, OpSequencer *osr)
{
  m_filestore_dump_fmt.open_array_section("transactions");
  unsigned trans_num = 0;
  for (vector<ObjectStore::Transaction>::iterator i = ls.begin(); i != ls.end(); ++i, ++trans_num) {
    m_filestore_dump_fmt.open_object_section("transaction");
    m_filestore_dump_fmt.dump_string("osr", osr->get_name());
    m_filestore_dump_fmt.dump_unsigned("seq", seq);
    m_filestore_dump_fmt.dump_unsigned("trans_num", trans_num);
    (*i).dump(&m_filestore_dump_fmt);
    m_filestore_dump_fmt.close_section();
  }
  m_filestore_dump_fmt.close_section();
  m_filestore_dump_fmt.flush(m_filestore_dump);
  m_filestore_dump.flush();
}

void FileStore::set_xattr_limits_via_conf()
{
  uint32_t fs_xattr_size;
  uint32_t fs_xattrs;
  uint32_t fs_xattr_max_value_size;

  switch (m_fs_type) {
#if defined(__linux__)
  case XFS_SUPER_MAGIC:
    fs_xattr_size = cct->_conf->filestore_max_inline_xattr_size_xfs;
    fs_xattrs = cct->_conf->filestore_max_inline_xattrs_xfs;
    fs_xattr_max_value_size = cct->_conf->filestore_max_xattr_value_size_xfs;
    break;
  case BTRFS_SUPER_MAGIC:
    fs_xattr_size = cct->_conf->filestore_max_inline_xattr_size_btrfs;
    fs_xattrs = cct->_conf->filestore_max_inline_xattrs_btrfs;
    fs_xattr_max_value_size = cct->_conf->filestore_max_xattr_value_size_btrfs;
    break;
#endif
  default:
    fs_xattr_size = cct->_conf->filestore_max_inline_xattr_size_other;
    fs_xattrs = cct->_conf->filestore_max_inline_xattrs_other;
    fs_xattr_max_value_size = cct->_conf->filestore_max_xattr_value_size_other;
    break;
  }

  // Use override value if set
  if (cct->_conf->filestore_max_inline_xattr_size)
    m_filestore_max_inline_xattr_size = cct->_conf->filestore_max_inline_xattr_size;
  else
    m_filestore_max_inline_xattr_size = fs_xattr_size;

  // Use override value if set
  if (cct->_conf->filestore_max_inline_xattrs)
    m_filestore_max_inline_xattrs = cct->_conf->filestore_max_inline_xattrs;
  else
    m_filestore_max_inline_xattrs = fs_xattrs;

  // Use override value if set
  if (cct->_conf->filestore_max_xattr_value_size)
    m_filestore_max_xattr_value_size = cct->_conf->filestore_max_xattr_value_size;
  else
    m_filestore_max_xattr_value_size = fs_xattr_max_value_size;

  if (m_filestore_max_xattr_value_size < cct->_conf->osd_max_object_name_len) {
    derr << "WARNING: max attr value size ("
         << m_filestore_max_xattr_value_size
         << ") is smaller than osd_max_object_name_len ("
         << cct->_conf->osd_max_object_name_len
         << ").  Your backend filesystem appears to not support attrs large "
         << "enough to handle the configured max rados name size.  You may get "
         << "unexpected ENAMETOOLONG errors on rados operations or buggy "
         << "behavior"
         << dendl;
  }
}

uint64_t FileStore::estimate_objects_overhead(uint64_t num_objects)
{
  uint64_t res = num_objects * blk_size / 2; //assumes that each object uses ( in average ) additional 1/2 block due to FS allocation granularity.
  return res;
}

int FileStore::apply_layout_settings(const coll_t &cid)
{
  dout(20) << __func__ << " " << cid << dendl;
  Index index;
  int r = get_index(cid, &index);
  if (r < 0) {
    dout(10) << "Error getting index for " << cid << ": " << cpp_strerror(r)
             << dendl;
    return r;
  }

  return index->apply_layout_settings();
}


// -- FSSuperblock --

void FSSuperblock::encode(bufferlist &bl) const
{
  ENCODE_START(2, 1, bl);
  compat_features.encode(bl);
  ::encode(omap_backend, bl);
  ENCODE_FINISH(bl);
}

void FSSuperblock::decode(bufferlist::iterator &bl)
{
  DECODE_START(2, bl);
  compat_features.decode(bl);
  if (struct_v >= 2)
    ::decode(omap_backend, bl);
  else
    omap_backend = "leveldb";
  DECODE_FINISH(bl);
}

void FSSuperblock::dump(Formatter *f) const
{
  f->open_object_section("compat");
  compat_features.dump(f);
  f->dump_string("omap_backend", omap_backend);
  f->close_section();
}

void FSSuperblock::generate_test_instances(list<FSSuperblock*>& o)
{
  FSSuperblock z;
  o.push_back(new FSSuperblock(z));
  CompatSet::FeatureSet feature_compat;
  CompatSet::FeatureSet feature_ro_compat;
  CompatSet::FeatureSet feature_incompat;
  feature_incompat.insert(CEPH_FS_FEATURE_INCOMPAT_SHARDS);
  z.compat_features = CompatSet(feature_compat, feature_ro_compat,
                                feature_incompat);
  o.push_back(new FSSuperblock(z));
  z.omap_backend = "rocksdb";
  o.push_back(new FSSuperblock(z));
}