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

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

1 files changed, 2338 insertions, 0 deletions

diff --git a/src/key_value_store/kv_flat_btree_async.cc b/src/key_value_store/kv_flat_btree_async.cc
new file mode 100644
index 000000000..d84239409
--- /dev/null
+++ b/src/key_value_store/kv_flat_btree_async.cc
@@ -0,0 +1,2338 @@
+/*
+ * Key-value store using librados
+ *
+ * September 2, 2012
+ * Eleanor Cawthon
+ * eleanor.cawthon@inktank.com
+ *
+ * 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 "key_value_store/key_value_structure.h"
+#include "key_value_store/kv_flat_btree_async.h"
+#include "key_value_store/kvs_arg_types.h"
+#include "include/rados/librados.hpp"
+#include "common/ceph_context.h"
+#include "common/Clock.h"
+#include "include/types.h"
+
+#include <errno.h>
+#include <string>
+#include <iostream>
+#include <cassert>
+#include <climits>
+#include <cmath>
+#include <sstream>
+#include <stdlib.h>
+#include <iterator>
+
+using ceph::bufferlist;
+
+bool index_data::is_timed_out(utime_t now, utime_t timeout) const {
+  return prefix != "" && now - ts > timeout;
+}
+
+void IndexCache::clear() {
+  k2itmap.clear();
+  t2kmap.clear();
+}
+
+void IndexCache::push(const string &key, const index_data &idata) {
+  if (cache_size == 0) {
+    return;
+  }
+  index_data old_idata;
+  map<key_data, pair<index_data, utime_t> >::iterator old_it =
+      k2itmap.lower_bound(key_data(key));
+  if (old_it != k2itmap.end()) {
+    t2kmap.erase(old_it->second.second);
+    k2itmap.erase(old_it);
+  }
+  map<key_data, pair<index_data, utime_t> >::iterator new_it =
+      k2itmap.find(idata.kdata);
+  if (new_it != k2itmap.end()) {
+    utime_t old_time = new_it->second.second;
+    t2kmap.erase(old_time);
+  }
+  utime_t time = ceph_clock_now();
+  k2itmap[idata.kdata] = make_pair(idata, time);
+  t2kmap[time] = idata.kdata;
+  if ((int)k2itmap.size() > cache_size) {
+    pop();
+  }
+
+}
+
+void IndexCache::push(const index_data &idata) {
+  if (cache_size == 0) {
+    return;
+  }
+  if (k2itmap.count(idata.kdata) > 0) {
+    utime_t old_time = k2itmap[idata.kdata].second;
+    t2kmap.erase(old_time);
+    k2itmap.erase(idata.kdata);
+  }
+  utime_t time = ceph_clock_now();
+  k2itmap[idata.kdata] = make_pair(idata, time);
+  t2kmap[time] = idata.kdata;
+  if ((int)k2itmap.size() > cache_size) {
+    pop();
+  }
+}
+
+void IndexCache::pop() {
+  if (cache_size == 0) {
+    return;
+  }
+  map<utime_t, key_data>::iterator it = t2kmap.begin();
+  utime_t time = it->first;
+  key_data kdata = it->second;
+  k2itmap.erase(kdata);
+  t2kmap.erase(time);
+}
+
+void IndexCache::erase(key_data kdata) {
+  if (cache_size == 0) {
+    return;
+  }
+  if (k2itmap.count(kdata) > 0) {
+    utime_t c = k2itmap[kdata].second;
+    k2itmap.erase(kdata);
+    t2kmap.erase(c);
+  }
+}
+
+int IndexCache::get(const string &key, index_data *idata) const {
+  if (cache_size == 0) {
+    return -ENODATA;
+  }
+  if ((int)k2itmap.size() == 0) {
+    return -ENODATA;
+  }
+  map<key_data, pair<index_data, utime_t> >::const_iterator it =
+      k2itmap.lower_bound(key_data(key));
+  if (it == k2itmap.end() || !(it->second.first.min_kdata < key_data(key))) {
+    return -ENODATA;
+  } else {
+    *idata = it->second.first;
+  }
+  return 0;
+}
+
+int IndexCache::get(const string &key, index_data *idata,
+    index_data *next_idata) const {
+  if (cache_size == 0) {
+    return -ENODATA;
+  }
+  map<key_data, pair<index_data, utime_t> >::const_iterator it =
+      k2itmap.lower_bound(key_data(key));
+  if (it == k2itmap.end() || ++it == k2itmap.end()) {
+    return -ENODATA;
+  } else {
+    --it;
+    if (!(it->second.first.min_kdata < key_data(key))){
+      //stale, should be reread.
+      return -ENODATA;
+    } else {
+      *idata = it->second.first;
+      ++it;
+      if (it != k2itmap.end()) {
+	*next_idata = it->second.first;
+      }
+    }
+  }
+  return 0;
+}
+
+int KvFlatBtreeAsync::nothing() {
+  return 0;
+}
+
+int KvFlatBtreeAsync::wait() {
+  if (rand() % 10 == 0) {
+    usleep(wait_ms);
+  }
+  return 0;
+}
+
+int KvFlatBtreeAsync::suicide() {
+  if (rand() % 10 == 0) {
+    if (verbose) cout << client_name << " is suiciding" << std::endl;
+    return 1;
+  }
+  return 0;
+}
+
+int KvFlatBtreeAsync::next(const index_data &idata, index_data * out_data)
+{
+  if (verbose) cout << "\t\t" << client_name << "-next: finding next of "
+      << idata.str()
+      << std::endl;
+  int err = 0;
+  librados::ObjectReadOperation oro;
+  std::map<std::string, bufferlist> kvs;
+  oro.omap_get_vals2(idata.kdata.encoded(),1,&kvs, nullptr, &err);
+  err = io_ctx.operate(index_name, &oro, NULL);
+  if (err < 0){
+    if (verbose) cout << "\t\t\t" << client_name
+	<< "-next: getting index failed with error "
+	<< err << std::endl;
+    return err;
+  }
+  if (!kvs.empty()) {
+    out_data->kdata.parse(kvs.begin()->first);
+    auto b = kvs.begin()->second.cbegin();
+    out_data->decode(b);
+    if (idata.is_timed_out(ceph_clock_now(), timeout)) {
+      if (verbose) cout << client_name << " THINKS THE OTHER CLIENT DIED."
+	  << std::endl;
+      //the client died after deleting the object. clean up.
+      cleanup(idata, err);
+    }
+  } else {
+    err = -EOVERFLOW;
+  }
+  return err;
+}
+
+int KvFlatBtreeAsync::prev(const index_data &idata, index_data * out_data)
+{
+  if (verbose) cout << "\t\t" << client_name << "-prev: finding prev of "
+      << idata.str() << std::endl;
+  int err = 0;
+  bufferlist inbl;
+  idata_from_idata_args in_args;
+  in_args.idata = idata;
+  in_args.encode(inbl);
+  bufferlist outbl;
+  err = io_ctx.exec(index_name,"kvs", "get_prev_idata", inbl, outbl);
+  if (err < 0){
+    if (verbose) cout << "\t\t\t" << client_name
+	<< "-prev: getting index failed with error "
+	<< err << std::endl;
+    if (idata.is_timed_out(ceph_clock_now(), timeout)) {
+      if (verbose) cout << client_name << " THINKS THE OTHER CLIENT DIED."
+	  << std::endl;
+      //the client died after deleting the object. clean up.
+      err = cleanup(idata, err);
+      if (err == -ESUICIDE) {
+	return err;
+      } else {
+	err = 0;
+      }
+    }
+    return err;
+  }
+  auto it = outbl.cbegin();
+  in_args.decode(it);
+  *out_data = in_args.next_idata;
+  if (verbose) cout << "\t\t" << client_name << "-prev: prev is "
+      << out_data->str()
+      << std::endl;
+  return err;
+}
+
+int KvFlatBtreeAsync::read_index(const string &key, index_data * idata,
+    index_data * next_idata, bool force_update) {
+  int err = 0;
+  if (!force_update) {
+    if (verbose) cout << "\t" << client_name
+	<< "-read_index: getting index_data for " << key
+	<< " from cache" << std::endl;
+    icache_lock.lock();
+    if (next_idata != NULL) {
+      err = icache.get(key, idata, next_idata);
+    } else {
+      err = icache.get(key, idata);
+    }
+    icache_lock.unlock();
+
+    if (err == 0) {
+      //if (verbose) cout << "CACHE SUCCESS" << std::endl;
+      return err;
+    } else {
+      if (verbose) cout << "NOT IN CACHE" << std::endl;
+    }
+  }
+
+  if (verbose) cout << "\t" << client_name
+      << "-read_index: getting index_data for " << key
+      << " from object" << std::endl;
+  librados::ObjectReadOperation oro;
+  bufferlist raw_val;
+  std::set<std::string> key_set;
+  key_set.insert(key_data(key).encoded());
+  std::map<std::string, bufferlist> kvmap;
+  std::map<std::string, bufferlist> dupmap;
+  oro.omap_get_vals_by_keys(key_set, &dupmap, &err);
+  oro.omap_get_vals2(key_data(key).encoded(),
+      (cache_size / cache_refresh >= 2? cache_size / cache_refresh: 2),
+      &kvmap, nullptr, &err);
+  err = io_ctx.operate(index_name, &oro, NULL);
+  utime_t mytime = ceph_clock_now();
+  if (err < 0){
+    cerr << "\t" << client_name
+	<< "-read_index: getting keys failed with "
+	<< err << std::endl;
+    ceph_abort_msg(client_name + "-read_index: reading index failed");
+    return err;
+  }
+  kvmap.insert(dupmap.begin(), dupmap.end());
+  for (map<string, bufferlist>::iterator it = ++kvmap.begin();
+      it != kvmap.end();
+      ++it) {
+    bufferlist bl = it->second;
+    auto blit = bl.cbegin();
+    index_data this_idata;
+    this_idata.decode(blit);
+    if (this_idata.is_timed_out(mytime, timeout)) {
+      if (verbose) cout << client_name
+	  << " THINKS THE OTHER CLIENT DIED. (mytime is "
+  	<< mytime.sec() << "." << mytime.usec() << ", idata.ts is "
+  	<< this_idata.ts.sec() << "." << this_idata.ts.usec()
+  	<< ", it has been " << (mytime - this_idata.ts).sec()
+	<< '.' << (mytime - this_idata.ts).usec()
+	<< ", timeout is " << timeout << ")" << std::endl;
+      //the client died after deleting the object. clean up.
+      if (cleanup(this_idata, -EPREFIX) == -ESUICIDE) {
+        return -ESUICIDE;
+      }
+      return read_index(key, idata, next_idata, force_update);
+    }
+    std::scoped_lock l{icache_lock};
+    icache.push(this_idata);
+  }
+  auto b = kvmap.begin()->second.cbegin();
+  idata->decode(b);
+  idata->kdata.parse(kvmap.begin()->first);
+  if (verbose) cout << "\t" << client_name << "-read_index: kvmap_size is "
+      << kvmap.size()
+      << ", idata is " << idata->str() << std::endl;
+
+  ceph_assert(idata->obj != "");
+  icache_lock.lock();
+  icache.push(key, *idata);
+  icache_lock.unlock();
+
+  if (next_idata != NULL && idata->kdata.prefix != "1") {
+    next_idata->kdata.parse((++kvmap.begin())->first);
+    auto nb = (++kvmap.begin())->second.cbegin();
+    next_idata->decode(nb);
+    std::scoped_lock l{icache_lock};
+    icache.push(*next_idata);
+  }
+  return err;
+}
+
+int KvFlatBtreeAsync::split(const index_data &idata) {
+  int err = 0;
+  opmap['l']++;
+
+  if (idata.prefix != "") {
+    return -EPREFIX;
+  }
+
+  rebalance_args args;
+  args.bound = 2 * k - 1;
+  args.comparator = CEPH_OSD_CMPXATTR_OP_GT;
+  err = read_object(idata.obj, &args);
+  args.odata.max_kdata = idata.kdata;
+  if (err < 0) {
+    if (verbose) cout << "\t\t" << client_name << "-split: read object "
+	<< args.odata.name
+	<< " got " << err << std::endl;
+    return err;
+  }
+
+  if (verbose) cout << "\t\t" << client_name << "-split: splitting "
+      << idata.obj
+      << ", which has size " << args.odata.size
+      << " and actual size " << args.odata.omap.size() << std::endl;
+
+  ///////preparations that happen outside the critical section
+  //for prefix index
+  vector<object_data> to_create;
+  vector<object_data> to_delete;
+  to_delete.push_back(object_data(idata.min_kdata,
+      args.odata.max_kdata, args.odata.name, args.odata.version));
+
+  //for lower half object
+  map<std::string, bufferlist>::const_iterator it = args.odata.omap.begin();
+  client_index_lock.lock();
+  to_create.push_back(object_data(to_string(client_name, client_index++)));
+  client_index_lock.unlock();
+  for (int i = 0; i < k; i++) {
+    to_create[0].omap.insert(*it);
+    ++it;
+  }
+  to_create[0].min_kdata = idata.min_kdata;
+  to_create[0].max_kdata = key_data(to_create[0].omap.rbegin()->first);
+
+  //for upper half object
+  client_index_lock.lock();
+  to_create.push_back(object_data(to_create[0].max_kdata,
+        args.odata.max_kdata,
+        to_string(client_name, client_index++)));
+  client_index_lock.unlock();
+  to_create[1].omap.insert(
+      ++args.odata.omap.find(to_create[0].omap.rbegin()->first),
+      args.odata.omap.end());
+
+  //setting up operations
+  librados::ObjectWriteOperation owos[6];
+  vector<pair<pair<int, string>, librados::ObjectWriteOperation*> > ops;
+  index_data out_data;
+  set_up_prefix_index(to_create, to_delete, &owos[0], &out_data, &err);
+  ops.push_back(make_pair(
+      pair<int, string>(ADD_PREFIX, index_name),
+      &owos[0]));
+  for (int i = 1; i < 6; i++) {
+    ops.push_back(make_pair(make_pair(0,""), &owos[i]));
+  }
+  set_up_ops(to_create, to_delete, &ops, out_data, &err);
+
+  /////BEGIN CRITICAL SECTION/////
+  //put prefix on index entry for idata.val
+  err = perform_ops("\t\t" + client_name + "-split:", out_data, &ops);
+  if (err < 0) {
+    return err;
+  }
+  if (verbose) cout << "\t\t" << client_name << "-split: done splitting."
+      << std::endl;
+  /////END CRITICAL SECTION/////
+  icache_lock.lock();
+  for (vector<delete_data>::iterator it = out_data.to_delete.begin();
+      it != out_data.to_delete.end(); ++it) {
+    icache.erase(it->max);
+  }
+  for (vector<create_data>::iterator it = out_data.to_create.begin();
+      it != out_data.to_create.end(); ++it) {
+    icache.push(index_data(*it));
+  }
+  icache_lock.unlock();
+  return err;
+}
+
+int KvFlatBtreeAsync::rebalance(const index_data &idata1,
+    const index_data &next_idata){
+  opmap['m']++;
+  int err = 0;
+
+  if (idata1.prefix != "") {
+    return -EPREFIX;
+  }
+
+  rebalance_args args1;
+  args1.bound = k + 1;
+  args1.comparator = CEPH_OSD_CMPXATTR_OP_LT;
+  index_data idata2 = next_idata;
+
+  rebalance_args args2;
+  args2.bound = k + 1;
+  args2.comparator = CEPH_OSD_CMPXATTR_OP_LT;
+
+  if (idata1.kdata.prefix == "1") {
+    //this is the highest key in the index, so it doesn't have a next.
+
+    //read the index for the previous entry
+    err = prev(idata1, &idata2);
+    if (err == -ERANGE) {
+      if (verbose) cout << "\t\t" << client_name
+	  << "-rebalance: this is the only node, "
+  	  << "so aborting" << std::endl;
+      return -EUCLEAN;
+    } else if (err < 0) {
+      return err;
+    }
+
+    //read the first object
+    err = read_object(idata1.obj, &args2);
+    if (err < 0) {
+      if (verbose) cout << "reading " << idata1.obj << " failed with " << err
+	  << std::endl;
+      if (err == -ENOENT) {
+	return -ECANCELED;
+      }
+      return err;
+    }
+    args2.odata.min_kdata = idata1.min_kdata;
+    args2.odata.max_kdata = idata1.kdata;
+
+    //read the second object
+    args1.bound = 2 * k + 1;
+    err = read_object(idata2.obj, &args1);
+    if (err < 0) {
+      if (verbose) cout << "reading " << idata1.obj << " failed with " << err
+	  << std::endl;
+      return err;
+    }
+    args1.odata.min_kdata = idata2.min_kdata;
+    args1.odata.max_kdata = idata2.kdata;
+
+    if (verbose) cout << "\t\t" << client_name << "-rebalance: read "
+	<< idata2.obj
+        << ". size: " << args1.odata.size << " version: "
+        << args1.odata.version
+        << std::endl;
+  } else {
+    assert (next_idata.obj != "");
+    //there is a next key, so get it.
+    err = read_object(idata1.obj, &args1);
+    if (err < 0) {
+      if (verbose) cout << "reading " << idata1.obj << " failed with " << err
+	  << std::endl;
+      return err;
+    }
+    args1.odata.min_kdata = idata1.min_kdata;
+    args1.odata.max_kdata = idata1.kdata;
+
+    args2.bound = 2 * k + 1;
+    err = read_object(idata2.obj, &args2);
+    if (err < 0) {
+      if (verbose) cout << "reading " << idata1.obj << " failed with " << err
+	  << std::endl;
+      if (err == -ENOENT) {
+	return -ECANCELED;
+      }
+      return err;
+    }
+    args2.odata.min_kdata = idata2.min_kdata;
+    args2.odata.max_kdata = idata2.kdata;
+
+    if (verbose) cout << "\t\t" << client_name << "-rebalance: read "
+	<< idata2.obj
+        << ". size: " << args2.odata.size << " version: "
+        << args2.odata.version
+        << std::endl;
+  }
+
+  if (verbose) cout << "\t\t" << client_name << "-rebalance: o1 is "
+      << args1.odata.max_kdata.encoded() << ","
+      << args1.odata.name  << " with size " << args1.odata.size
+      << " , o2 is " << args2.odata.max_kdata.encoded()
+      << "," << args2.odata.name  << " with size " << args2.odata.size
+      << std::endl;
+
+  //calculations
+  if ((int)args1.odata.size > k && (int)args1.odata.size <= 2*k
+      && (int)args2.odata.size > k
+      && (int)args2.odata.size <= 2*k) {
+    //nothing to do
+    if (verbose) cout << "\t\t" << client_name
+	<< "-rebalance: both sizes in range, so"
+	<< " aborting " << std::endl;
+    return -EBALANCE;
+  } else if (idata1.prefix != "" || idata2.prefix != "") {
+    return -EPREFIX;
+  }
+
+  //this is the high object. it gets created regardless of rebalance or merge.
+  client_index_lock.lock();
+  string o2w = to_string(client_name, client_index++);
+  client_index_lock.unlock();
+  index_data idata;
+  vector<object_data> to_create;
+  vector<object_data> to_delete;
+  librados::ObjectWriteOperation create[2];//possibly only 1 will be used
+  librados::ObjectWriteOperation other_ops[6];
+  vector<pair<pair<int, string>, librados::ObjectWriteOperation*> > ops;
+  ops.push_back(make_pair(
+      pair<int, string>(ADD_PREFIX, index_name),
+      &other_ops[0]));
+
+  if ((int)args1.odata.size + (int)args2.odata.size <= 2*k) {
+    //merge
+    if (verbose) cout << "\t\t" << client_name << "-rebalance: merging "
+	<< args1.odata.name
+	<< " and " << args2.odata.name << " to get " << o2w
+	<< std::endl;
+    map<string, bufferlist> write2_map;
+    write2_map.insert(args1.odata.omap.begin(), args1.odata.omap.end());
+    write2_map.insert(args2.odata.omap.begin(), args2.odata.omap.end());
+    to_create.push_back(object_data(args1.odata.min_kdata,
+	args2.odata.max_kdata, o2w, write2_map));
+    ops.push_back(make_pair(
+	pair<int, string>(MAKE_OBJECT, o2w),
+	&create[0]));
+    ceph_assert((int)write2_map.size() <= 2*k);
+  } else {
+    //rebalance
+    if (verbose) cout << "\t\t" << client_name << "-rebalance: rebalancing "
+	<< args1.odata.name
+	<< " and " << args2.odata.name << std::endl;
+    map<std::string, bufferlist> write1_map;
+    map<std::string, bufferlist> write2_map;
+    map<std::string, bufferlist>::iterator it;
+    client_index_lock.lock();
+    string o1w = to_string(client_name, client_index++);
+    client_index_lock.unlock();
+    int target_size_1 = ceil(((int)args1.odata.size + (int)args2.odata.size)
+	/ 2.0);
+    if (args1.odata.max_kdata != idata1.kdata) {
+      //this should be true if idata1 is the high object
+      target_size_1 = floor(((int)args1.odata.size + (int)args2.odata.size)
+	  / 2.0);
+    }
+    for (it = args1.odata.omap.begin();
+	it != args1.odata.omap.end() && (int)write1_map.size()
+	    < target_size_1;
+	++it) {
+      write1_map.insert(*it);
+    }
+    if (it != args1.odata.omap.end()){
+      //write1_map is full, so put the rest in write2_map
+      write2_map.insert(it, args1.odata.omap.end());
+      write2_map.insert(args2.odata.omap.begin(), args2.odata.omap.end());
+    } else {
+      //args1.odata.omap was small, and write2_map still needs more
+      map<std::string, bufferlist>::iterator it2;
+      for(it2 = args2.odata.omap.begin();
+	  (it2 != args2.odata.omap.end()) && ((int)write1_map.size()
+	      < target_size_1);
+	  ++it2) {
+	write1_map.insert(*it2);
+      }
+      write2_map.insert(it2, args2.odata.omap.end());
+    }
+    if (verbose) cout << "\t\t" << client_name
+	<< "-rebalance: write1_map has size "
+	<< write1_map.size() << ", write2_map.size() is " << write2_map.size()
+	<< std::endl;
+    //at this point, write1_map and write2_map should have the correct pairs
+    to_create.push_back(object_data(args1.odata.min_kdata,
+	key_data(write1_map.rbegin()->first),
+	o1w,write1_map));
+    to_create.push_back(object_data( key_data(write1_map.rbegin()->first),
+	args2.odata.max_kdata, o2w, write2_map));
+    ops.push_back(make_pair(
+	pair<int, string>(MAKE_OBJECT, o1w),
+	&create[0]));
+    ops.push_back(make_pair(
+	pair<int, string>(MAKE_OBJECT, o2w),
+	&create[1]));
+  }
+
+  to_delete.push_back(object_data(args1.odata.min_kdata,
+      args1.odata.max_kdata, args1.odata.name, args1.odata.version));
+  to_delete.push_back(object_data(args2.odata.min_kdata,
+      args2.odata.max_kdata, args2.odata.name, args2.odata.version));
+  for (int i = 1; i < 6; i++) {
+    ops.push_back(make_pair(make_pair(0,""), &other_ops[i]));
+  }
+
+  index_data out_data;
+  set_up_prefix_index(to_create, to_delete, &other_ops[0], &out_data, &err);
+  set_up_ops(to_create, to_delete, &ops, out_data, &err);
+
+  //at this point, all operations should be completely set up.
+  /////BEGIN CRITICAL SECTION/////
+  err = perform_ops("\t\t" + client_name + "-rebalance:", out_data, &ops);
+  if (err < 0) {
+    return err;
+  }
+  icache_lock.lock();
+  for (vector<delete_data>::iterator it = out_data.to_delete.begin();
+      it != out_data.to_delete.end(); ++it) {
+    icache.erase(it->max);
+  }
+  for (vector<create_data>::iterator it = out_data.to_create.begin();
+      it != out_data.to_create.end(); ++it) {
+    icache.push(index_data(*it));
+  }
+  icache_lock.unlock();
+  if (verbose) cout << "\t\t" << client_name << "-rebalance: done rebalancing."
+      << std::endl;
+  /////END CRITICAL SECTION/////
+  return err;
+}
+
+int KvFlatBtreeAsync::read_object(const string &obj, object_data * odata) {
+  librados::ObjectReadOperation get_obj;
+  librados::AioCompletion * obj_aioc = rados.aio_create_completion();
+  int err;
+  bufferlist unw_bl;
+  odata->name = obj;
+  get_obj.omap_get_vals2("", LONG_MAX, &odata->omap, nullptr, &err);
+  get_obj.getxattr("unwritable", &unw_bl, &err);
+  io_ctx.aio_operate(obj, obj_aioc, &get_obj, NULL);
+  obj_aioc->wait_for_complete();
+  err = obj_aioc->get_return_value();
+  if (err < 0){
+    //possibly -ENOENT, meaning someone else deleted it.
+    obj_aioc->release();
+    return err;
+  }
+  odata->unwritable = string(unw_bl.c_str(), unw_bl.length()) == "1";
+  odata->version = obj_aioc->get_version64();
+  odata->size = odata->omap.size();
+  obj_aioc->release();
+  return 0;
+}
+
+int KvFlatBtreeAsync::read_object(const string &obj, rebalance_args * args) {
+  bufferlist inbl;
+  args->encode(inbl);
+  bufferlist outbl;
+  int err;
+  librados::AioCompletion * a = rados.aio_create_completion();
+  io_ctx.aio_exec(obj, a, "kvs", "maybe_read_for_balance", inbl, &outbl);
+  a->wait_for_complete();
+  err = a->get_return_value();
+  if (err < 0) {
+    if (verbose) cout << "\t\t" << client_name
+	<< "-read_object: reading failed with "
+	<< err << std::endl;
+    a->release();
+    return err;
+  }
+  auto it = outbl.cbegin();
+  args->decode(it);
+  args->odata.name = obj;
+  args->odata.version = a->get_version64();
+  a->release();
+  return err;
+}
+
+void KvFlatBtreeAsync::set_up_prefix_index(
+    const vector<object_data> &to_create,
+    const vector<object_data> &to_delete,
+    librados::ObjectWriteOperation * owo,
+    index_data * idata,
+    int * err) {
+  std::map<std::string, pair<bufferlist, int> > assertions;
+  map<string, bufferlist> to_insert;
+  idata->prefix = "1";
+  idata->ts = ceph_clock_now();
+  for(vector<object_data>::const_iterator it = to_create.begin();
+      it != to_create.end();
+      ++it) {
+    create_data c(it->min_kdata, it->max_kdata, it->name);
+    idata->to_create.push_back(c);
+  }
+  for(vector<object_data>::const_iterator it = to_delete.begin();
+      it != to_delete.end();
+      ++it) {
+    delete_data d(it->min_kdata, it->max_kdata, it->name, it->version);
+    idata->to_delete.push_back(d);
+  }
+  for(vector<object_data>::const_iterator it = to_delete.begin();
+      it != to_delete.end();
+      ++it) {
+    idata->obj = it->name;
+    idata->min_kdata = it->min_kdata;
+    idata->kdata = it->max_kdata;
+    bufferlist insert;
+    idata->encode(insert);
+    to_insert[it->max_kdata.encoded()] = insert;
+    index_data this_entry;
+    this_entry.min_kdata = idata->min_kdata;
+    this_entry.kdata = idata->kdata;
+    this_entry.obj = idata->obj;
+    assertions[it->max_kdata.encoded()] = pair<bufferlist, int>
+    (to_bl(this_entry),	CEPH_OSD_CMPXATTR_OP_EQ);
+    if (verbose) cout << "\t\t\t" << client_name
+	<< "-setup_prefix: will assert "
+	<< this_entry.str() << std::endl;
+  }
+  ceph_assert(*err == 0);
+  owo->omap_cmp(assertions, err);
+  if (to_create.size() <= 2) {
+    owo->omap_set(to_insert);
+  }
+}
+
+//some args can be null if there are no corresponding entries in p
+void KvFlatBtreeAsync::set_up_ops(
+    const vector<object_data> &create_vector,
+    const vector<object_data> &delete_vector,
+    vector<pair<pair<int, string>, librados::ObjectWriteOperation*> > * ops,
+    const index_data &idata,
+    int * err) {
+  vector<pair<pair<int, string>,
+    librados::ObjectWriteOperation* > >::iterator it;
+
+  //skip the prefixing part
+  for(it = ops->begin(); it->first.first == ADD_PREFIX; ++it) {}
+  map<string, bufferlist> to_insert;
+  std::set<string> to_remove;
+  map<string, pair<bufferlist, int> > assertions;
+  if (create_vector.size() > 0) {
+    for (int i = 0; i < (int)idata.to_delete.size(); ++i) {
+      it->first = pair<int, string>(UNWRITE_OBJECT, idata.to_delete[i].obj);
+      set_up_unwrite_object(delete_vector[i].version, it->second);
+      ++it;
+    }
+  }
+  for (int i = 0; i < (int)idata.to_create.size(); ++i) {
+    index_data this_entry(idata.to_create[i].max, idata.to_create[i].min,
+	idata.to_create[i].obj);
+    to_insert[idata.to_create[i].max.encoded()] = to_bl(this_entry);
+    if (idata.to_create.size() <= 2) {
+      it->first = pair<int, string>(MAKE_OBJECT, idata.to_create[i].obj);
+    } else {
+      it->first = pair<int, string>(AIO_MAKE_OBJECT, idata.to_create[i].obj);
+    }
+    set_up_make_object(create_vector[i].omap, it->second);
+    ++it;
+  }
+  for (int i = 0; i < (int)idata.to_delete.size(); ++i) {
+    index_data this_entry = idata;
+    this_entry.obj = idata.to_delete[i].obj;
+    this_entry.min_kdata = idata.to_delete[i].min;
+    this_entry.kdata = idata.to_delete[i].max;
+    if (verbose) cout << "\t\t\t" << client_name << "-setup_ops: will assert "
+	<< this_entry.str() << std::endl;
+    assertions[idata.to_delete[i].max.encoded()] = pair<bufferlist, int>(
+	to_bl(this_entry), CEPH_OSD_CMPXATTR_OP_EQ);
+    to_remove.insert(idata.to_delete[i].max.encoded());
+    it->first = pair<int, string>(REMOVE_OBJECT, idata.to_delete[i].obj);
+    set_up_delete_object(it->second);
+    ++it;
+  }
+  if ((int)idata.to_create.size() <= 2) {
+    it->second->omap_cmp(assertions, err);
+  }
+  it->second->omap_rm_keys(to_remove);
+  it->second->omap_set(to_insert);
+
+
+  it->first = pair<int, string>(REMOVE_PREFIX, index_name);
+}
+
+void KvFlatBtreeAsync::set_up_make_object(
+    const map<std::string, bufferlist> &to_set,
+    librados::ObjectWriteOperation *owo) {
+  bufferlist inbl;
+  encode(to_set, inbl);
+  owo->exec("kvs", "create_with_omap", inbl);
+}
+
+void KvFlatBtreeAsync::set_up_unwrite_object(
+    const int &ver, librados::ObjectWriteOperation *owo) {
+  if (ver > 0) {
+    owo->assert_version(ver);
+  }
+  owo->cmpxattr("unwritable", CEPH_OSD_CMPXATTR_OP_EQ, to_bl("0"));
+  owo->setxattr("unwritable", to_bl("1"));
+}
+
+void KvFlatBtreeAsync::set_up_restore_object(
+    librados::ObjectWriteOperation *owo) {
+  owo->cmpxattr("unwritable", CEPH_OSD_CMPXATTR_OP_EQ, to_bl("1"));
+  owo->setxattr("unwritable", to_bl("0"));
+}
+
+void KvFlatBtreeAsync::set_up_delete_object(
+    librados::ObjectWriteOperation *owo) {
+  owo->cmpxattr("unwritable", CEPH_OSD_CMPXATTR_OP_EQ, to_bl("1"));
+  owo->remove();
+}
+
+int KvFlatBtreeAsync::perform_ops(const string &debug_prefix,
+    const index_data &idata,
+    vector<pair<pair<int, string>, librados::ObjectWriteOperation*> > *ops) {
+  int err = 0;
+  vector<librados::AioCompletion*> aiocs(idata.to_create.size());
+  int count = 0;
+  for (vector<pair<pair<int, string>,
+      librados::ObjectWriteOperation*> >::iterator it = ops->begin();
+      it != ops->end(); ++it) {
+    if ((((KeyValueStructure *)this)->*KvFlatBtreeAsync::interrupt)() == 1 ) {
+      return -ESUICIDE;
+    }
+    switch (it->first.first) {
+    case ADD_PREFIX://prefixing
+      if (verbose) cout << debug_prefix << " adding prefix" << std::endl;
+      err = io_ctx.operate(index_name, it->second);
+      if (err < 0) {
+        if (verbose) cout << debug_prefix << " prefixing the index failed with "
+            << err << std::endl;
+        return -EPREFIX;
+      }
+      if (verbose) cout << debug_prefix << " prefix added." << std::endl;
+      break;
+    case UNWRITE_OBJECT://marking
+      if (verbose) cout << debug_prefix << " marking " << it->first.second
+      << std::endl;
+      err = io_ctx.operate(it->first.second, it->second);
+      if (err < 0) {
+	//most likely because it changed, in which case it will be -ERANGE
+	if (verbose) cout << debug_prefix << " marking " << it->first.second
+	    << "failed with code" << err << std::endl;
+	if (it->first.second == (*idata.to_delete.begin()).max.encoded()) {
+	  if (cleanup(idata, -EFIRSTOBJ) == -ESUICIDE) {
+	    return -ESUICIDE;
+	  }
+	} else {
+	  if (cleanup(idata, -ERANGE) == -ESUICIDE) {
+	    return -ESUICIDE;
+	  }
+	}
+	return err;
+      }
+      if (verbose) cout << debug_prefix << " marked " << it->first.second
+	  << std::endl;
+      break;
+    case MAKE_OBJECT://creating
+      if (verbose) cout << debug_prefix << " creating " << it->first.second
+	 << std::endl;
+      err = io_ctx.operate(it->first.second, it->second);
+      if (err < 0) {
+	//this can happen if someone else was cleaning up after us.
+	if (verbose) cout << debug_prefix << " creating " << it->first.second
+	    << " failed"
+	    << " with code " << err << std::endl;
+	if (err == -EEXIST) {
+	  //someone thinks we died, so die
+	  if (verbose) cout << client_name << " is suiciding!" << std::endl;
+	  return -ESUICIDE;
+	} else {
+	  ceph_abort();
+	}
+	return err;
+      }
+      if (verbose || idata.to_create.size() > 2) {
+	cout << debug_prefix << " created object " << it->first.second
+	  << std::endl;
+      }
+      break;
+    case AIO_MAKE_OBJECT:
+      cout << debug_prefix << " launching asynchronous create "
+	  << it->first.second << std::endl;
+      aiocs[count] = rados.aio_create_completion();
+      io_ctx.aio_operate(it->first.second, aiocs[count], it->second);
+      count++;
+      if ((int)idata.to_create.size() == count) {
+	cout << "starting aiowrite waiting loop" << std::endl;
+	  for (count -= 1; count >= 0; count--) {
+	    aiocs[count]->wait_for_complete();
+	    err = aiocs[count]->get_return_value();
+	    if (err < 0) {
+	      //this can happen if someone else was cleaning up after us.
+	      cerr << debug_prefix << " a create failed"
+		  << " with code " << err << std::endl;
+	      if (err == -EEXIST) {
+		//someone thinks we died, so die
+		cerr << client_name << " is suiciding!" << std::endl;
+		return -ESUICIDE;
+	      } else {
+		ceph_abort();
+	      }
+	      return err;
+	    }
+	    if (verbose || idata.to_create.size() > 2) {
+	      cout << debug_prefix << " completed aio " << aiocs.size() - count
+		  << "/" << aiocs.size() << std::endl;
+	    }
+	  }
+      }
+      break;
+    case REMOVE_OBJECT://deleting
+      if (verbose) cout << debug_prefix << " deleting " << it->first.second
+      << std::endl;
+      err = io_ctx.operate(it->first.second, it->second);
+      if (err < 0) {
+	//if someone else called cleanup on this prefix first
+	if (verbose) cout << debug_prefix << " deleting " << it->first.second
+	    << "failed with code" << err << std::endl;
+      }
+      if (verbose) cout << debug_prefix << " deleted " << it->first.second
+	  << std::endl;
+      break;
+    case REMOVE_PREFIX://rewriting index
+      if (verbose) cout << debug_prefix << " updating index " << std::endl;
+      err = io_ctx.operate(index_name, it->second);
+      if (err < 0) {
+        if (verbose) cout << debug_prefix
+    	<< " rewriting the index failed with code " << err
+        << ". someone else must have thought we died, so dying" << std::endl;
+        return -ETIMEDOUT;
+      }
+      if (verbose) cout << debug_prefix << " updated index." << std::endl;
+      break;
+    case RESTORE_OBJECT:
+      if (verbose) cout << debug_prefix << " restoring " << it->first.second
+      << std::endl;
+      err = io_ctx.operate(it->first.second, it->second);
+      if (err < 0) {
+	if (verbose) cout << debug_prefix << "restoring " << it->first.second
+	    << " failed"
+	    << " with " << err << std::endl;
+	return err;
+      }
+      if (verbose) cout << debug_prefix << " restored " << it->first.second
+	  << std::endl;
+      break;
+    default:
+      if (verbose) cout << debug_prefix << " performing unknown op on "
+      << it->first.second
+	<< std::endl;
+      err = io_ctx.operate(index_name, it->second);
+      if (err < 0) {
+	if (verbose) cout << debug_prefix << " unknown op on "
+	    << it->first.second
+	    << " failed with " << err << std::endl;
+	return err;
+      }
+      if (verbose) cout << debug_prefix << " unknown op on "
+	  << it->first.second
+	  << " succeeded." << std::endl;
+      break;
+    }
+  }
+
+  return err;
+}
+
+int KvFlatBtreeAsync::cleanup(const index_data &idata, const int &error) {
+  if (verbose) cout << "\t\t" << client_name << ": cleaning up after "
+      << idata.str()
+      << std::endl;
+  int err = 0;
+  ceph_assert(idata.prefix != "");
+  map<std::string,bufferlist> new_index;
+  map<std::string, pair<bufferlist, int> > assertions;
+  switch (error) {
+  case -EFIRSTOBJ: {
+    //this happens if the split or rebalance failed to mark the first object,
+    //meaning only the index needs to be changed.
+    //restore objects that had been marked unwritable.
+    for(vector<delete_data >::const_iterator it =
+	idata.to_delete.begin();
+	it != idata.to_delete.end(); ++it) {
+      index_data this_entry;
+      this_entry.obj = (*it).obj;
+      this_entry.min_kdata = it->min;
+      this_entry.kdata = it->max;
+      new_index[it->max.encoded()] = to_bl(this_entry);
+      this_entry = idata;
+      this_entry.obj = it->obj;
+      this_entry.min_kdata = it->min;
+      this_entry.kdata = it->max;
+      if (verbose) cout << "\t\t\t" << client_name
+	  << "-cleanup: will assert index contains "
+  	<< this_entry.str() << std::endl;
+      assertions[it->max.encoded()] =
+	  pair<bufferlist, int>(to_bl(this_entry),
+	      CEPH_OSD_CMPXATTR_OP_EQ);
+    }
+
+    //update the index
+    librados::ObjectWriteOperation update_index;
+    update_index.omap_cmp(assertions, &err);
+    update_index.omap_set(new_index);
+    if (verbose) cout << "\t\t\t" << client_name << "-cleanup: updating index"
+	<< std::endl;
+    if ((((KeyValueStructure *)this)->*KvFlatBtreeAsync::interrupt)() == 1 ) {
+      return -ESUICIDE;
+    }
+    err = io_ctx.operate(index_name, &update_index);
+    if (err < 0) {
+      if (verbose) cout << "\t\t\t" << client_name
+	  << "-cleanup: rewriting failed with "
+	  << err << ". returning -ECANCELED" << std::endl;
+      return -ECANCELED;
+    }
+    if (verbose) cout << "\t\t\t" << client_name
+	<< "-cleanup: updated index. cleanup done."
+	<< std::endl;
+    break;
+  }
+  case -ERANGE: {
+    //this happens if a split or rebalance fails to mark an object. It is a
+    //special case of rolling back that does not have to deal with new objects.
+
+    //restore objects that had been marked unwritable.
+    vector<delete_data >::const_iterator it;
+    for(it = idata.to_delete.begin();
+	it != idata.to_delete.end(); ++it) {
+      index_data this_entry;
+      this_entry.obj = (*it).obj;
+      this_entry.min_kdata = it->min;
+      this_entry.kdata = it->max;
+      new_index[it->max.encoded()] = to_bl(this_entry);
+      this_entry = idata;
+      this_entry.obj = it->obj;
+      this_entry.min_kdata = it->min;
+      this_entry.kdata = it->max;
+      if (verbose) cout << "\t\t\t" << client_name
+	  << "-cleanup: will assert index contains "
+  	<< this_entry.str() << std::endl;
+      assertions[it->max.encoded()] =
+	  pair<bufferlist, int>(to_bl(this_entry),
+	      CEPH_OSD_CMPXATTR_OP_EQ);
+    }
+    it = idata.to_delete.begin();
+    librados::ObjectWriteOperation restore;
+    set_up_restore_object(&restore);
+    if ((((KeyValueStructure *)this)->*KvFlatBtreeAsync::interrupt)() == 1 ) {
+      return -ESUICIDE;
+    }
+    if (verbose) cout << "\t\t\t" << client_name << "-cleanup: restoring "
+	<< it->obj
+	<< std::endl;
+    err = io_ctx.operate(it->obj, &restore);
+    if (err < 0) {
+      //i.e., -ECANCELED because the object was already restored by someone
+      //else
+	if (verbose) cout << "\t\t\t" << client_name << "-cleanup: restoring "
+	    << it->obj
+	  << " failed with " << err << std::endl;
+    } else {
+      if (verbose) cout << "\t\t\t" << client_name << "-cleanup: restored "
+	  << it->obj
+	   << std::endl;
+    }
+
+    //update the index
+    librados::ObjectWriteOperation update_index;
+    update_index.omap_cmp(assertions, &err);
+    update_index.omap_set(new_index);
+    if (verbose) cout << "\t\t\t" << client_name << "-cleanup: updating index"
+	<< std::endl;
+    if ((((KeyValueStructure *)this)->*KvFlatBtreeAsync::interrupt)() == 1 ) {
+      return -ESUICIDE;
+    }
+    err = io_ctx.operate(index_name, &update_index);
+    if (err < 0) {
+      if (verbose) cout << "\t\t\t" << client_name
+	  << "-cleanup: rewriting failed with "
+	  << err << ". returning -ECANCELED" << std::endl;
+      return -ECANCELED;
+    }
+    if (verbose) cout << "\t\t\t" << client_name
+	<< "-cleanup: updated index. cleanup done."
+	<< std::endl;
+    break;
+  }
+  case -ENOENT: {
+    if (verbose) cout << "\t\t" << client_name << "-cleanup: rolling forward"
+	<< std::endl;
+    //all changes were created except for updating the index and possibly
+    //deleting the objects. roll forward.
+    vector<pair<pair<int, string>, librados::ObjectWriteOperation*> > ops;
+    vector<librados::ObjectWriteOperation> owos(idata.to_delete.size() + 1);
+    for (int i = 0; i <= (int)idata.to_delete.size(); ++i) {
+      ops.push_back(make_pair(pair<int, string>(0, ""), &owos[i]));
+    }
+    set_up_ops(vector<object_data>(),
+	vector<object_data>(), &ops, idata, &err);
+    err = perform_ops("\t\t" + client_name + "-cleanup:", idata, &ops);
+    if (err < 0) {
+      if (err == -ESUICIDE) {
+	return -ESUICIDE;
+      }
+      if (verbose) cout << "\t\t\t" << client_name
+	  << "-cleanup: rewriting failed with "
+	  << err << ". returning -ECANCELED" << std::endl;
+      return -ECANCELED;
+    }
+    if (verbose) cout << "\t\t\t" << client_name << "-cleanup: updated index"
+	<< std::endl;
+    break;
+  }
+  default: {
+    //roll back all changes.
+    if (verbose) cout << "\t\t" << client_name << "-cleanup: rolling back"
+	<< std::endl;
+    map<std::string,bufferlist> new_index;
+    std::set<string> to_remove;
+    map<std::string, pair<bufferlist, int> > assertions;
+
+    //mark the objects to be created. if someone else already has, die.
+    for(vector<create_data >::const_reverse_iterator it =
+	idata.to_create.rbegin();
+	it != idata.to_create.rend(); ++it) {
+      librados::ObjectWriteOperation rm;
+      set_up_unwrite_object(0, &rm);
+      if ((((KeyValueStructure *)this)->*KvFlatBtreeAsync::interrupt)() == 1 )
+      {
+	return -ESUICIDE;
+      }
+      if (verbose) cout << "\t\t\t" << client_name << "-cleanup: marking "
+	  << it->obj
+	<< std::endl;
+      err = io_ctx.operate(it->obj, &rm);
+      if (err < 0) {
+	if (verbose) cout << "\t\t\t" << client_name << "-cleanup: marking "
+	    << it->obj
+            << " failed with " << err << std::endl;
+      } else {
+      if (verbose) cout << "\t\t\t" << client_name << "-cleanup: marked "
+	  << it->obj
+        << std::endl;
+      }
+    }
+
+    //restore objects that had been marked unwritable.
+    for(vector<delete_data >::const_iterator it =
+	idata.to_delete.begin();
+	it != idata.to_delete.end(); ++it) {
+      index_data this_entry;
+      this_entry.obj = (*it).obj;
+      this_entry.min_kdata = it->min;
+      this_entry.kdata = it->max;
+      new_index[it->max.encoded()] = to_bl(this_entry);
+      this_entry = idata;
+      this_entry.obj = it->obj;
+      this_entry.min_kdata = it->min;
+      this_entry.kdata = it->max;
+      if (verbose) cout << "\t\t\t" << client_name
+	  << "-cleanup: will assert index contains "
+  	<< this_entry.str() << std::endl;
+      assertions[it->max.encoded()] =
+	  pair<bufferlist, int>(to_bl(this_entry),
+	      CEPH_OSD_CMPXATTR_OP_EQ);
+      librados::ObjectWriteOperation restore;
+      set_up_restore_object(&restore);
+      if (verbose) cout << "\t\t\t" << client_name
+	  << "-cleanup: will assert index contains "
+	  << this_entry.str() << std::endl;
+      if ((((KeyValueStructure *)this)->*KvFlatBtreeAsync::interrupt)() == 1 )
+      {
+	return -ESUICIDE;
+      }
+      if (verbose) cout << "\t\t\t" << client_name << "-cleanup: restoring "
+	  << it->obj
+          << std::endl;
+      err = io_ctx.operate(it->obj, &restore);
+      if (err == -ENOENT) {
+	//it had gotten far enough to be rolled forward - unmark the objects
+	//and roll forward.
+	if (verbose) cout << "\t\t\t" << client_name
+	    << "-cleanup: roll forward instead"
+	    << std::endl;
+	for(vector<create_data >::const_iterator cit =
+	    idata.to_create.begin();
+	    cit != idata.to_create.end(); ++cit) {
+	  librados::ObjectWriteOperation res;
+	  set_up_restore_object(&res);
+	  if ((((KeyValueStructure *)this)->*KvFlatBtreeAsync::interrupt)()
+	      == 1 ) {
+	    return -ECANCELED;
+	  }
+	  if (verbose) cout << "\t\t\t" << client_name
+	      << "-cleanup: restoring " << cit->obj
+	    << std::endl;
+	  err = io_ctx.operate(cit->obj, &res);
+	  if (err < 0) {
+	    if (verbose) cout << "\t\t\t" << client_name
+		<< "-cleanup: restoring "
+		<< cit->obj << " failed with " << err << std::endl;
+	  }
+	  if (verbose) cout << "\t\t\t" << client_name << "-cleanup: restored "
+	      << cit->obj
+	    << std::endl;
+	}
+	return cleanup(idata, -ENOENT);
+      } else if (err < 0) {
+	//i.e., -ECANCELED because the object was already restored by someone
+	//else
+	  if (verbose) cout << "\t\t\t" << client_name
+	      << "-cleanup: restoring " << it->obj
+	    << " failed with " << err << std::endl;
+      } else {
+	if (verbose) cout << "\t\t\t" << client_name << "-cleanup: restored "
+	    << it->obj
+             << std::endl;
+      }
+    }
+
+    //remove the new objects
+    for(vector<create_data >::const_reverse_iterator it =
+	idata.to_create.rbegin();
+	it != idata.to_create.rend(); ++it) {
+      to_remove.insert(it->max.encoded());
+      librados::ObjectWriteOperation rm;
+      rm.remove();
+      if ((((KeyValueStructure *)this)->*KvFlatBtreeAsync::interrupt)() == 1 )
+      {
+	return -ESUICIDE;
+      }
+      if (verbose) cout << "\t\t\t" << client_name << "-cleanup: removing "
+	  << it->obj
+          << std::endl;
+      err = io_ctx.operate(it->obj, &rm);
+      if (err < 0) {
+	if (verbose) cout << "\t\t\t" << client_name
+	    << "-cleanup: failed to remove "
+	    << it->obj << std::endl;
+      } else {
+	if (verbose) cout << "\t\t\t" << client_name << "-cleanup: removed "
+	    << it->obj
+            << std::endl;
+      }
+    }
+
+    //update the index
+    librados::ObjectWriteOperation update_index;
+    update_index.omap_cmp(assertions, &err);
+    update_index.omap_rm_keys(to_remove);
+    update_index.omap_set(new_index);
+    if (verbose) cout << "\t\t\t" << client_name << "-cleanup: updating index"
+	<< std::endl;
+    if ((((KeyValueStructure *)this)->*KvFlatBtreeAsync::interrupt)() == 1 ) {
+      return -ESUICIDE;
+    }
+    err = io_ctx.operate(index_name, &update_index);
+    if (err < 0) {
+      if (verbose) cout << "\t\t\t" << client_name
+	  << "-cleanup: rewriting failed with "
+	  << err << ". returning -ECANCELED" << std::endl;
+      return -ECANCELED;
+    }
+    if (verbose) cout << "\t\t\t" << client_name
+	<< "-cleanup: updated index. cleanup done."
+	<< std::endl;
+    break;
+  }
+  }
+  return err;
+}
+
+string KvFlatBtreeAsync::to_string(string s, int i) {
+  stringstream ret;
+  ret << s << i;
+  return ret.str();
+}
+
+string KvFlatBtreeAsync::get_name() {
+  return rados_id;
+}
+
+void KvFlatBtreeAsync::set_inject(injection_t inject, int wait_time) {
+  interrupt = inject;
+  wait_ms = wait_time;
+}
+
+int KvFlatBtreeAsync::setup(int argc, const char** argv) {
+  int r = rados.init(rados_id.c_str());
+  if (r < 0) {
+    cerr << "error during init" << r << std::endl;
+    return r;
+  }
+  r = rados.conf_parse_argv(argc, argv);
+  if (r < 0) {
+    cerr << "error during parsing args" << r << std::endl;
+    return r;
+  }
+  r = rados.conf_parse_env(NULL);
+  if (r < 0) {
+    cerr << "error during parsing env" << r << std::endl;
+    return r;
+  }
+  r = rados.conf_read_file(NULL);
+  if (r < 0) {
+    cerr << "error during read file: " << r << std::endl;
+    return r;
+  }
+  r = rados.connect();
+  if (r < 0) {
+    cerr << "error during connect: " << r << std::endl;
+    return r;
+  }
+  r = rados.ioctx_create(pool_name.c_str(), io_ctx);
+  if (r < 0) {
+    cerr << "error creating io ctx: " << r << std::endl;
+    rados.shutdown();
+    return r;
+  }
+
+  librados::ObjectWriteOperation make_index;
+  make_index.create(true);
+  map<std::string,bufferlist> index_map;
+  index_data idata;
+  idata.obj = client_name;
+  idata.min_kdata.raw_key = "";
+  idata.kdata = key_data("");
+  index_map["1"] = to_bl(idata);
+  make_index.omap_set(index_map);
+  r = io_ctx.operate(index_name, &make_index);
+  if (r < 0) {
+    if (verbose) cout << client_name << ": Making the index failed with code "
+	<< r
+	<< std::endl;
+    return 0;
+  }
+  if (verbose) cout << client_name << ": created index object" << std::endl;
+
+  librados::ObjectWriteOperation make_max_obj;
+  make_max_obj.create(true);
+  make_max_obj.setxattr("unwritable", to_bl("0"));
+  make_max_obj.setxattr("size", to_bl("0"));
+  r = io_ctx.operate(client_name, &make_max_obj);
+  if (r < 0) {
+    if (verbose) cout << client_name << ": Setting xattr failed with code "
+	<< r
+	<< std::endl;
+  }
+
+  return 0;
+}
+
+int KvFlatBtreeAsync::set(const string &key, const bufferlist &val,
+    bool update_on_existing) {
+  if (verbose) cout << client_name << " is "
+      << (update_on_existing? "updating " : "setting ")
+      << key << std::endl;
+  int err = 0;
+  utime_t mytime;
+  index_data idata(key);
+
+  if (verbose) cout << "\t" << client_name << ": finding oid" << std::endl;
+  err = read_index(key, &idata, NULL, false);
+  if (err < 0) {
+    if (verbose) cout << "\t" << client_name
+	<< ": getting oid failed with code "
+	<< err << std::endl;
+    return err;
+  }
+  if (verbose) cout << "\t" << client_name << ": index data is " << idata.str()
+      << ", object is " << idata.obj << std::endl;
+
+  err = set_op(key, val, update_on_existing, idata);
+
+  if (verbose) cout << "\t" << client_name << ": finished set with " << err
+      << std::endl;
+  return err;
+}
+
+int KvFlatBtreeAsync::set_op(const string &key, const bufferlist &val,
+    bool update_on_existing, index_data &idata) {
+  //write
+
+  bufferlist inbl;
+  omap_set_args args;
+  args.bound = 2 * k;
+  args.exclusive = !update_on_existing;
+  args.omap[key] = val;
+  args.encode(inbl);
+
+  librados::ObjectWriteOperation owo;
+  owo.exec("kvs", "omap_insert", inbl);
+  if ((((KeyValueStructure *)this)->*KvFlatBtreeAsync::interrupt)() == 1 ) {
+    if (verbose) cout << client_name << " IS SUICIDING!" << std::endl;
+    return -ESUICIDE;
+  }
+  if (verbose) cout << "\t" << client_name << ": inserting " << key
+      << " into object "
+      << idata.obj << std::endl;
+  int err = io_ctx.operate(idata.obj, &owo);
+  if (err < 0) {
+    switch (err) {
+    case -EEXIST: {
+      //the key already exists and this is an exclusive insert.
+      cerr << "\t" << client_name << ": writing key failed with "
+  	<< err << std::endl;
+      return err;
+    }
+    case -EKEYREJECTED: {
+      //the object needs to be split.
+      do {
+	if (verbose) cout << "\t" << client_name << ": running split on "
+	    << idata.obj
+            << std::endl;
+        err = read_index(key, &idata, NULL, true);
+        if (err < 0) {
+	  if (verbose) cout << "\t" << client_name
+	      << ": getting oid failed with code "
+	      << err << std::endl;
+	  return err;
+        }
+        err = split(idata);
+        if (err < 0 && err != -ENOENT && err != -EBALANCE) {
+          if (verbose) cerr << "\t" << client_name << ": split failed with "
+              << err << std::endl;
+	  int ret = handle_set_rm_errors(err, idata.obj, key, &idata, NULL);
+	  switch (ret) {
+	  case -ESUICIDE:
+	    if (verbose) cout << client_name << " IS SUICIDING!" << std::endl;
+	    return ret;
+	  case 1:
+	    return set_op(key, val, update_on_existing, idata);
+	  case 2:
+	    return err;
+	  }
+        }
+      } while (err < 0 && err != -EBALANCE && err != -ENOENT);
+      err = read_index(key, &idata, NULL, true);
+      if (err < 0) {
+	if (verbose) cout << "\t" << client_name
+	    << ": getting oid failed with code "
+	    << err << std::endl;
+	return err;
+      }
+      return set_op(key, val, update_on_existing, idata);
+    }
+    default:
+      if (verbose) cerr << "\t" << client_name << ": writing obj failed with "
+  	<< err << std::endl;
+      if (err == -ENOENT || err == -EACCES) {
+	if (err == -ENOENT) {
+	  if (verbose) cout << "CACHE FAILURE" << std::endl;
+	}
+	err = read_index(key, &idata, NULL, true);
+	if (err < 0) {
+	  if (verbose) cout << "\t" << client_name
+	      << ": getting oid failed with code "
+	      << err << std::endl;
+	  return err;
+	}
+	if (verbose) cout << "\t" << client_name << ": index data is "
+	    << idata.str()
+	    << ", object is " << idata.obj << std::endl;
+	return set_op(key, val, update_on_existing, idata);
+      } else {
+	return err;
+      }
+    }
+  }
+  return 0;
+}
+
+int KvFlatBtreeAsync::remove(const string &key) {
+  if (verbose) cout << client_name << ": removing " << key << std::endl;
+  int err = 0;
+  string obj;
+  utime_t mytime;
+  index_data idata;
+  index_data next_idata;
+
+  if (verbose) cout << "\t" << client_name << ": finding oid" << std::endl;
+  err = read_index(key, &idata, &next_idata, false);
+  if (err < 0) {
+    if (verbose) cout << "getting oid failed with code " << err << std::endl;
+    return err;
+  }
+  obj = idata.obj;
+  if (verbose) cout << "\t" << client_name << ": idata is " << idata.str()
+      << ", next_idata is " << next_idata.str()
+      << ", obj is " << obj << std::endl;
+
+  err = remove_op(key, idata, next_idata);
+
+  if (verbose) cout << "\t" << client_name << ": finished remove with " << err
+      << " and exiting" << std::endl;
+  return err;
+}
+
+int KvFlatBtreeAsync::remove_op(const string &key, index_data &idata,
+    index_data &next_idata) {
+  //write
+  bufferlist inbl;
+  omap_rm_args args;
+  args.bound = k;
+  args.omap.insert(key);
+  args.encode(inbl);
+
+  librados::ObjectWriteOperation owo;
+  owo.exec("kvs", "omap_remove", inbl);
+  if ((((KeyValueStructure *)this)->*KvFlatBtreeAsync::interrupt)() == 1 ) {
+    if (verbose) cout << client_name << " IS SUICIDING!" << std::endl;
+    return -ESUICIDE;
+  }
+  if (verbose) cout << "\t" << client_name << ": removing " << key << " from "
+      << idata.obj
+      << std::endl;
+  int err = io_ctx.operate(idata.obj, &owo);
+  if (err < 0) {
+    if (verbose) cout << "\t" << client_name << ": writing obj failed with "
+	<< err << std::endl;
+    switch (err) {
+    case -ENODATA: {
+      //the key does not exist in the object
+      return err;
+    }
+    case -EKEYREJECTED: {
+      //the object needs to be split.
+      do {
+        if (verbose) cerr << "\t" << client_name << ": running rebalance on "
+            << idata.obj << std::endl;
+        err = read_index(key, &idata, &next_idata, true);
+        if (err < 0) {
+	  if (verbose) cout << "\t" << client_name
+	      << ": getting oid failed with code "
+	      << err << std::endl;
+	  return err;
+        }
+        err = rebalance(idata, next_idata);
+        if (err < 0 && err != -ENOENT && err != -EBALANCE) {
+          if (verbose) cerr << "\t" << client_name << ": rebalance returned "
+              << err << std::endl;
+          int ret = handle_set_rm_errors(err, idata.obj, key, &idata,
+              &next_idata);
+          switch (ret) {
+          case -ESUICIDE:
+            if (verbose) cout << client_name << " IS SUICIDING!" << std::endl;
+            return err;
+          case 1:
+            return remove_op(key, idata, next_idata);
+          case 2:
+            return err;
+	    break;
+          case -EUCLEAN:
+            //this is the only node, so it's ok to go below k.
+            librados::ObjectWriteOperation owo;
+            bufferlist inbl;
+            omap_rm_args args;
+            args.bound = 0;
+            args.omap.insert(key);
+            args.encode(inbl);
+            owo.exec("kvs", "omap_remove", inbl);
+            if ((((KeyValueStructure *)this)->*KvFlatBtreeAsync::interrupt)()
+        	== 1 ) {
+              if (verbose) cout << client_name << " IS SUICIDING!"
+        	  << std::endl;
+              return -ESUICIDE;
+            }
+            if (verbose) cout << "\t" << client_name << ": removing " << key
+        	<< " from "
+        	<< idata.obj
+                << std::endl;
+            int err = io_ctx.operate(idata.obj, &owo);
+            if (err == 0) {
+              return 0;
+            }
+          }
+        }
+      } while (err < 0 && err != -EBALANCE && err != -ENOENT);
+      err = read_index(key, &idata, &next_idata, true);
+      if (err < 0) {
+	if (verbose) cout << "\t" << client_name
+	    << ": getting oid failed with code "
+	    << err << std::endl;
+	return err;
+      }
+      return remove(key);
+    }
+    default:
+      if (err == -ENOENT || err == -EACCES) {
+	err = read_index(key, &idata, &next_idata, true);
+	if (err < 0) {
+	  if (verbose) cout << "\t" << client_name
+	      << ": getting oid failed with code "
+	      << err << std::endl;
+	  return err;
+	}
+	if (verbose) cout << "\t" << client_name << ": index data is "
+	    << idata.str()
+	    << ", object is " << idata.obj << std::endl;
+	//idea: we read the time every time we read the index anyway - store it.
+	return remove_op(key, idata, next_idata);
+      } else {
+	return err;
+      }
+    }
+  }
+  return 0;
+}
+
+int KvFlatBtreeAsync::handle_set_rm_errors(int &err, string obj,
+    string key,
+    index_data * idata, index_data * next_idata) {
+  if (err == -ESUICIDE) {
+    return err;
+  } else if (err == -ECANCELED //if an object was unwritable or index changed
+      || err == -EPREFIX //if there is currently a prefix
+      || err == -ETIMEDOUT// if the index changes during the op - i.e. cleanup
+      || err == -EACCES) //possible if we were acting on old index data
+  {
+    err = read_index(key, idata, next_idata, true);
+    if (err < 0) {
+      return err;
+    }
+    if (verbose) cout << "\t" << client_name << ": prefix is " << idata->str()
+	<< std::endl;
+    if (idata->obj != obj) {
+      //someone else has split or cleaned up or something. start over.
+      return 1;//meaning repeat
+    }
+  } else if (err != -ETIMEDOUT && err != -ERANGE && err != -EACCES
+      && err != -EUCLEAN){
+    if (verbose) cout << "\t" << client_name
+	<< ": split encountered an unexpected error: " << err
+	<< std::endl;
+    return 2;
+  }
+  return err;
+}
+
+int KvFlatBtreeAsync::get(const string &key, bufferlist *val) {
+  opmap['g']++;
+  if (verbose) cout << client_name << ": getting " << key << std::endl;
+  int err = 0;
+  index_data idata;
+  utime_t mytime;
+
+  if ((((KeyValueStructure *)this)->*KvFlatBtreeAsync::interrupt)() == 1 ) {
+    return -ESUICIDE;
+  }
+  err = read_index(key, &idata, NULL, false);
+  mytime = ceph_clock_now();
+  if (err < 0) {
+    if (verbose) cout << "getting oid failed with code " << err << std::endl;
+    return err;
+  }
+
+  err = get_op(key, val, idata);
+
+  if (verbose) cout << client_name << ": got " << key << " with " << err
+      << std::endl;
+
+  return err;
+}
+
+int KvFlatBtreeAsync::get_op(const string &key, bufferlist *val,
+    index_data &idata) {
+  int err = 0;
+  std::set<std::string> key_set;
+  key_set.insert(key);
+  map<std::string,bufferlist> omap;
+  librados::ObjectReadOperation read;
+  read.omap_get_vals_by_keys(key_set, &omap, &err);
+  err = io_ctx.operate(idata.obj, &read, NULL);
+  if (err < 0) {
+    if (err == -ENOENT) {
+	err = read_index(key, &idata, NULL, true);
+	if (err < 0) {
+	  if (verbose) cout << "\t" << client_name
+	      << ": getting oid failed with code "
+	      << err << std::endl;
+	  return err;
+	}
+	if (verbose) cout << "\t" << client_name << ": index data is "
+	    << idata.str()
+	    << ", object is " << idata.obj << std::endl;
+	return get_op(key, val, idata);
+    } else {
+      if (verbose) cout << client_name
+	  << ": get encountered an unexpected error: " << err
+	  << std::endl;
+      return err;
+    }
+  }
+
+  *val = omap[key];
+  return err;
+}
+
+void *KvFlatBtreeAsync::pset(void *ptr) {
+  struct aio_set_args *args = (struct aio_set_args *)ptr;
+  *args->err =
+      args->kvba->KvFlatBtreeAsync::set((string)args->key,
+	  (bufferlist)args->val, (bool)args->exc);
+  args->cb(args->err, args->cb_args);
+  delete args;
+  return NULL;
+}
+
+void KvFlatBtreeAsync::aio_set(const string &key, const bufferlist &val,
+    bool exclusive, callback cb, void * cb_args, int * err) {
+  aio_set_args *args = new aio_set_args();
+  args->kvba = this;
+  args->key = key;
+  args->val = val;
+  args->exc = exclusive;
+  args->cb = cb;
+  args->cb_args = cb_args;
+  args->err = err;
+  pthread_t t;
+  int r = pthread_create(&t, NULL, pset, (void*)args);
+  if (r < 0) {
+    *args->err = r;
+    return;
+  }
+  pthread_detach(t);
+}
+
+void *KvFlatBtreeAsync::prm(void *ptr) {
+  struct aio_rm_args *args = (struct aio_rm_args *)ptr;
+  *args->err =
+      args->kvba->KvFlatBtreeAsync::remove((string)args->key);
+  args->cb(args->err, args->cb_args);
+  delete args;
+  return NULL;
+}
+
+void KvFlatBtreeAsync::aio_remove(const string &key,
+    callback cb, void * cb_args, int * err) {
+  aio_rm_args * args = new aio_rm_args();
+  args->kvba = this;
+  args->key = key;
+  args->cb = cb;
+  args->cb_args = cb_args;
+  args->err = err;
+  pthread_t t;
+  int r = pthread_create(&t, NULL, prm, (void*)args);
+  if (r < 0) {
+    *args->err = r;
+    return;
+  }
+  pthread_detach(t);
+}
+
+void *KvFlatBtreeAsync::pget(void *ptr) {
+  struct aio_get_args *args = (struct aio_get_args *)ptr;
+  *args->err =
+      args->kvba->KvFlatBtreeAsync::get((string)args->key,
+	  (bufferlist *)args->val);
+  args->cb(args->err, args->cb_args);
+  delete args;
+  return NULL;
+}
+
+void KvFlatBtreeAsync::aio_get(const string &key, bufferlist *val,
+    callback cb, void * cb_args, int * err) {
+  aio_get_args * args = new aio_get_args();
+  args->kvba = this;
+  args->key = key;
+  args->val = val;
+  args->cb = cb;
+  args->cb_args = cb_args;
+  args->err = err;
+  pthread_t t;
+  int r = pthread_create(&t, NULL, pget, (void*)args);
+  if (r < 0) {
+    *args->err = r;
+    return;
+  }
+  pthread_detach(t);
+}
+
+int KvFlatBtreeAsync::set_many(const map<string, bufferlist> &in_map) {
+  int err = 0;
+  bufferlist inbl;
+  bufferlist outbl;
+  std::set<string> keys;
+
+  map<string, bufferlist> big_map;
+  for (map<string, bufferlist>::const_iterator it = in_map.begin();
+      it != in_map.end(); ++it) {
+    keys.insert(it->first);
+    big_map.insert(*it);
+  }
+
+  if (verbose) cout << "created key set and big_map" << std::endl;
+
+  encode(keys, inbl);
+  librados::AioCompletion * aioc = rados.aio_create_completion();
+  io_ctx.aio_exec(index_name, aioc,  "kvs", "read_many", inbl, &outbl);
+  aioc->wait_for_complete();
+  err = aioc->get_return_value();
+  aioc->release();
+  if (err < 0) {
+    cerr << "getting index failed with " << err << std::endl;
+    return err;
+  }
+
+  map<string, bufferlist> imap;//read from the index
+  auto blit = outbl.cbegin();
+  decode(imap, blit);
+
+  if (verbose) cout << "finished reading index for objects. there are "
+      << imap.size() << " entries that need to be changed. " << std::endl;
+
+
+  vector<object_data> to_delete;
+
+  vector<object_data> to_create;
+
+  if (verbose) cout << "setting up to_delete and to_create vectors from index "
+      << "map" << std::endl;
+  //set up to_delete from index map
+  for (map<string, bufferlist>::iterator it = imap.begin(); it != imap.end();
+      ++it){
+    index_data idata;
+    blit = it->second.begin();
+    idata.decode(blit);
+    to_delete.push_back(object_data(idata.min_kdata, idata.kdata, idata.obj));
+    err = read_object(idata.obj, &to_delete[to_delete.size() - 1]);
+    if (err < 0) {
+      if (verbose) cout << "reading " << idata.obj << " failed with " << err
+	  << std::endl;
+      return set_many(in_map);
+    }
+
+    big_map.insert(to_delete[to_delete.size() - 1].omap.begin(),
+	to_delete[to_delete.size() - 1].omap.end());
+  }
+
+  to_create.push_back(object_data(
+	to_string(client_name, client_index++)));
+  to_create[0].min_kdata = to_delete[0].min_kdata;
+
+  for(map<string, bufferlist>::iterator it = big_map.begin();
+      it != big_map.end(); ++it) {
+    if (to_create[to_create.size() - 1].omap.size() == 1.5 * k) {
+      to_create[to_create.size() - 1].max_kdata =
+	  key_data(to_create[to_create.size() - 1]
+	                         .omap.rbegin()->first);
+
+      to_create.push_back(object_data(
+	to_string(client_name, client_index++)));
+      to_create[to_create.size() - 1].min_kdata =
+	  to_create[to_create.size() - 2].max_kdata;
+    }
+
+    to_create[to_create.size() - 1].omap.insert(*it);
+  }
+  to_create[to_create.size() - 1].max_kdata =
+      to_delete[to_delete.size() - 1].max_kdata;
+
+  vector<librados::ObjectWriteOperation> owos(2 + 2 * to_delete.size()
+					      + to_create.size());
+  vector<pair<pair<int, string>, librados::ObjectWriteOperation*> > ops;
+
+
+  index_data idata;
+  set_up_prefix_index(to_create, to_delete, &owos[0], &idata, &err);
+
+  if (verbose) cout << "finished making to_create and to_delete. "
+      << std::endl;
+
+  ops.push_back(make_pair(
+      pair<int, string>(ADD_PREFIX, index_name),
+      &owos[0]));
+  for (int i = 1; i < 2 + 2 * (int)to_delete.size() + (int)to_create.size();
+      i++) {
+    ops.push_back(make_pair(make_pair(0,""), &owos[i]));
+  }
+
+  set_up_ops(to_create, to_delete, &ops, idata, &err);
+
+  cout << "finished setting up ops. Starting critical section..." << std::endl;
+
+  /////BEGIN CRITICAL SECTION/////
+  //put prefix on index entry for idata.val
+  err = perform_ops("\t\t" + client_name + "-set_many:", idata, &ops);
+  if (err < 0) {
+    return set_many(in_map);
+  }
+  if (verbose) cout << "\t\t" << client_name << "-split: done splitting."
+      << std::endl;
+  /////END CRITICAL SECTION/////
+  std::scoped_lock l{icache_lock};
+  for (vector<delete_data>::iterator it = idata.to_delete.begin();
+      it != idata.to_delete.end(); ++it) {
+    icache.erase(it->max);
+  }
+  for (vector<create_data>::iterator it = idata.to_create.begin();
+      it != idata.to_create.end(); ++it) {
+    icache.push(index_data(*it));
+  }
+  return err;
+}
+
+int KvFlatBtreeAsync::remove_all() {
+  if (verbose) cout << client_name << ": removing all" << std::endl;
+  int err = 0;
+  librados::ObjectReadOperation oro;
+  librados::AioCompletion * oro_aioc = rados.aio_create_completion();
+  std::map<std::string, bufferlist> index_set;
+  oro.omap_get_vals2("",LONG_MAX,&index_set, nullptr, &err);
+  err = io_ctx.aio_operate(index_name, oro_aioc, &oro, NULL);
+  if (err < 0){
+    if (err == -ENOENT) {
+      return 0;
+    }
+    if (verbose) cout << "getting keys failed with error " << err << std::endl;
+    return err;
+  }
+  oro_aioc->wait_for_complete();
+  oro_aioc->release();
+
+  librados::ObjectWriteOperation rm_index;
+  librados::AioCompletion * rm_index_aioc = rados.aio_create_completion();
+  map<std::string,bufferlist> new_index;
+  new_index["1"] = index_set["1"];
+  rm_index.omap_clear();
+  rm_index.omap_set(new_index);
+  io_ctx.aio_operate(index_name, rm_index_aioc, &rm_index);
+  err = rm_index_aioc->get_return_value();
+  rm_index_aioc->release();
+  if (err < 0) {
+    if (verbose) cout << "rm index aioc failed with " << err
+	<< std::endl;
+    return err;
+  }
+
+  if (!index_set.empty()) {
+    for (std::map<std::string,bufferlist>::iterator it = index_set.begin();
+	it != index_set.end(); ++it){
+      librados::ObjectWriteOperation sub;
+      if (it->first == "1") {
+	sub.omap_clear();
+      } else {
+	sub.remove();
+      }
+      index_data idata;
+      auto b = it->second.cbegin();
+      idata.decode(b);
+      io_ctx.operate(idata.obj, &sub);
+    }
+  }
+
+  icache.clear();
+
+  return 0;
+}
+
+int KvFlatBtreeAsync::get_all_keys(std::set<std::string> *keys) {
+  if (verbose) cout << client_name << ": getting all keys" << std::endl;
+  int err = 0;
+  librados::ObjectReadOperation oro;
+  std::map<std::string,bufferlist> index_set;
+  oro.omap_get_vals2("",LONG_MAX,&index_set, nullptr, &err);
+  io_ctx.operate(index_name, &oro, NULL);
+  if (err < 0){
+    if (verbose) cout << "getting keys failed with error " << err << std::endl;
+    return err;
+  }
+  for (std::map<std::string,bufferlist>::iterator it = index_set.begin();
+      it != index_set.end(); ++it){
+    librados::ObjectReadOperation sub;
+    std::set<std::string> ret;
+    sub.omap_get_keys2("",LONG_MAX,&ret, nullptr, &err);
+    index_data idata;
+    auto b = it->second.cbegin();
+    idata.decode(b);
+    io_ctx.operate(idata.obj, &sub, NULL);
+    keys->insert(ret.begin(), ret.end());
+  }
+  return err;
+}
+
+int KvFlatBtreeAsync::get_all_keys_and_values(
+    map<std::string,bufferlist> *kv_map) {
+  if (verbose) cout << client_name << ": getting all keys and values"
+      << std::endl;
+  int err = 0;
+  librados::ObjectReadOperation first_read;
+  std::set<std::string> index_set;
+  first_read.omap_get_keys2("",LONG_MAX,&index_set, nullptr, &err);
+  io_ctx.operate(index_name, &first_read, NULL);
+  if (err < 0){
+    if (verbose) cout << "getting keys failed with error " << err << std::endl;
+    return err;
+  }
+  for (std::set<std::string>::iterator it = index_set.begin();
+      it != index_set.end(); ++it){
+    librados::ObjectReadOperation sub;
+    map<std::string, bufferlist> ret;
+    sub.omap_get_vals2("",LONG_MAX,&ret, nullptr, &err);
+    io_ctx.operate(*it, &sub, NULL);
+    kv_map->insert(ret.begin(), ret.end());
+  }
+  return err;
+}
+
+bool KvFlatBtreeAsync::is_consistent() {
+  int err;
+  bool ret = true;
+  if (verbose) cout << client_name << ": checking consistency" << std::endl;
+  std::map<std::string,bufferlist> index;
+  map<std::string, std::set<std::string> > sub_objs;
+  librados::ObjectReadOperation oro;
+  oro.omap_get_vals2("",LONG_MAX,&index, nullptr, &err);
+  io_ctx.operate(index_name, &oro, NULL);
+  if (err < 0){
+    //probably because the index doesn't exist - this might be ok.
+    for (librados::NObjectIterator oit = io_ctx.nobjects_begin();
+        oit != io_ctx.nobjects_end(); ++oit) {
+      //if this executes, there are floating objects.
+      cerr << "Not consistent! found floating object " << oit->get_oid()
+             << std::endl;
+      ret = false;
+    }
+    return ret;
+  }
+
+  std::map<std::string, string> parsed_index;
+  std::set<std::string> onames;
+  std::set<std::string> special_names;
+  for (map<std::string,bufferlist>::iterator it = index.begin();
+      it != index.end(); ++it) {
+    if (it->first != "") {
+      index_data idata;
+      auto b = it->second.cbegin();
+      idata.decode(b);
+      if (idata.prefix != "") {
+	for(vector<delete_data>::iterator dit = idata.to_delete.begin();
+	    dit != idata.to_delete.end(); ++dit) {
+	  librados::ObjectReadOperation oro;
+	  librados::AioCompletion * aioc = rados.aio_create_completion();
+	  bufferlist un;
+	  oro.getxattr("unwritable", &un, &err);
+	  io_ctx.aio_operate(dit->obj, aioc, &oro, NULL);
+	  aioc->wait_for_complete();
+	  err = aioc->get_return_value();
+	  if (ceph_clock_now() - idata.ts > timeout) {
+	    if (err < 0) {
+	      aioc->release();
+	      if (err == -ENOENT) {
+		continue;
+	      } else {
+		cerr << "Not consistent! reading object " << dit->obj
+		<< "returned " << err << std::endl;
+		ret = false;
+		break;
+	      }
+	    }
+	    if (atoi(string(un.c_str(), un.length()).c_str()) != 1 &&
+		aioc->get_version64() != dit->version) {
+	      cerr << "Not consistent! object " << dit->obj << " has been "
+		  << " modified since the client died was not cleaned up."
+		  << std::endl;
+	      ret = false;
+	    }
+	  }
+	  special_names.insert(dit->obj);
+	  aioc->release();
+	}
+	for(vector<create_data >::iterator cit = idata.to_create.begin();
+	    cit != idata.to_create.end(); ++cit) {
+	  special_names.insert(cit->obj);
+	}
+      }
+      parsed_index.insert(make_pair(it->first, idata.obj));
+      onames.insert(idata.obj);
+    }
+  }
+
+  //make sure that an object exists iff it either is the index
+  //or is listed in the index
+  for (librados::NObjectIterator oit = io_ctx.nobjects_begin();
+      oit != io_ctx.nobjects_end(); ++oit) {
+    string name = oit->get_oid();
+    if (name != index_name && onames.count(name) == 0
+	&& special_names.count(name) == 0) {
+      cerr << "Not consistent! found floating object " << name << std::endl;
+      ret = false;
+    }
+  }
+
+  //check objects
+  string prev = "";
+  for (std::map<std::string, string>::iterator it = parsed_index.begin();
+      it != parsed_index.end();
+      ++it) {
+    librados::ObjectReadOperation read;
+    read.omap_get_keys2("", LONG_MAX, &sub_objs[it->second], nullptr, &err);
+    err = io_ctx.operate(it->second, &read, NULL);
+    int size_int = (int)sub_objs[it->second].size();
+
+    //check that size is in the right range
+    if (it->first != "1" && special_names.count(it->second) == 0 &&
+	err != -ENOENT && (size_int > 2*k|| size_int < k)
+	&& parsed_index.size() > 1) {
+      cerr << "Not consistent! Object " << *it << " has size " << size_int
+	  << ", which is outside the acceptable range." << std::endl;
+      ret = false;
+    }
+
+    //check that all keys belong in that object
+    for(std::set<std::string>::iterator subit = sub_objs[it->second].begin();
+	subit != sub_objs[it->second].end(); ++subit) {
+      if ((it->first != "1"
+	  && *subit > it->first.substr(1,it->first.length()))
+	  || *subit <= prev) {
+	cerr << "Not consistent! key " << *subit << " does not belong in "
+	    << *it << std::endl;
+	cerr << "not last element, i.e. " << it->first << " not equal to 1? "
+	    << (it->first != "1") << std::endl
+	    << "greater than " << it->first.substr(1,it->first.length())
+	    <<"? " << (*subit > it->first.substr(1,it->first.length()))
+	    << std::endl
+	    << "less than or equal to " << prev << "? "
+	    << (*subit <= prev) << std::endl;
+	ret = false;
+      }
+    }
+
+    prev = it->first.substr(1,it->first.length());
+  }
+
+  if (!ret) {
+    if (verbose) cout << "failed consistency test - see error log"
+	<< std::endl;
+    cerr << str();
+  } else {
+    if (verbose) cout << "passed consistency test" << std::endl;
+  }
+  return ret;
+}
+
+string KvFlatBtreeAsync::str() {
+  stringstream ret;
+  ret << "Top-level map:" << std::endl;
+  int err = 0;
+  std::set<std::string> keys;
+  std::map<std::string,bufferlist> index;
+  librados::ObjectReadOperation oro;
+  librados::AioCompletion * top_aioc = rados.aio_create_completion();
+  oro.omap_get_vals2("",LONG_MAX,&index, nullptr, &err);
+  io_ctx.aio_operate(index_name, top_aioc, &oro, NULL);
+  top_aioc->wait_for_complete();
+  err = top_aioc->get_return_value();
+  top_aioc->release();
+  if (err < 0 && err != -5){
+    if (verbose) cout << "getting keys failed with error " << err << std::endl;
+    return ret.str();
+  }
+  if(index.empty()) {
+    ret << "There are no objects!" << std::endl;
+    return ret.str();
+  }
+
+  for (map<std::string,bufferlist>::iterator it = index.begin();
+      it != index.end(); ++it) {
+    keys.insert(string(it->second.c_str(), it->second.length())
+	.substr(1,it->second.length()));
+  }
+
+  vector<std::string> all_names;
+  vector<int> all_sizes(index.size());
+  vector<int> all_versions(index.size());
+  vector<bufferlist> all_unwrit(index.size());
+  vector<map<std::string,bufferlist> > all_maps(keys.size());
+  vector<map<std::string,bufferlist>::iterator> its(keys.size());
+  unsigned done = 0;
+  vector<bool> dones(keys.size());
+  ret << std::endl << string(150,'-') << std::endl;
+
+  for (map<std::string,bufferlist>::iterator it = index.begin();
+      it != index.end(); ++it){
+    index_data idata;
+    auto b = it->second.cbegin();
+    idata.decode(b);
+    string s = idata.str();
+    ret << "|" << string((148 -
+	((*it).first.length()+s.length()+3))/2,' ');
+    ret << (*it).first;
+    ret << " | ";
+    ret << string(idata.str());
+    ret << string((148 -
+	((*it).first.length()+s.length()+3))/2,' ');
+    ret << "|\t";
+    all_names.push_back(idata.obj);
+    ret << std::endl << string(150,'-') << std::endl;
+  }
+
+  int indexer = 0;
+
+  //get the object names and sizes
+  for(vector<std::string>::iterator it = all_names.begin(); it
+  != all_names.end();
+      ++it) {
+    librados::ObjectReadOperation oro;
+    librados::AioCompletion *aioc = rados.aio_create_completion();
+    oro.omap_get_vals2("", LONG_MAX, &all_maps[indexer], nullptr, &err);
+    oro.getxattr("unwritable", &all_unwrit[indexer], &err);
+    io_ctx.aio_operate(*it, aioc, &oro, NULL);
+    aioc->wait_for_complete();
+    if (aioc->get_return_value() < 0) {
+      ret << "reading" << *it << "failed: " << err << std::endl;
+      //return ret.str();
+    }
+    all_sizes[indexer] = all_maps[indexer].size();
+    all_versions[indexer] = aioc->get_version64();
+    indexer++;
+    aioc->release();
+  }
+
+  ret << "///////////////////OBJECT NAMES////////////////" << std::endl;
+  //HEADERS
+  ret << std::endl;
+  for (int i = 0; i < indexer; i++) {
+   ret << "---------------------------\t";
+  }
+  ret << std::endl;
+  for (int i = 0; i < indexer; i++) {
+    ret << "|" << string((25 -
+	(string("Bucket: ").length() + all_names[i].length()))/2, ' ');
+    ret << "Bucket: " << all_names[i];
+    ret << string((25 -
+    	(string("Bucket: ").length() + all_names[i].length()))/2, ' ') << "|\t";
+  }
+  ret << std::endl;
+  for (int i = 0; i < indexer; i++) {
+    its[i] = all_maps[i].begin();
+    ret << "|" << string((25 - (string("size: ").length()
+	+ to_string("",all_sizes[i]).length()))/2, ' ');
+    ret << "size: " << all_sizes[i];
+    ret << string((25 - (string("size: ").length()
+	  + to_string("",all_sizes[i]).length()))/2, ' ') << "|\t";
+  }
+  ret << std::endl;
+  for (int i = 0; i < indexer; i++) {
+    its[i] = all_maps[i].begin();
+    ret << "|" << string((25 - (string("version: ").length()
+	+ to_string("",all_versions[i]).length()))/2, ' ');
+    ret << "version: " << all_versions[i];
+    ret << string((25 - (string("version: ").length()
+	  + to_string("",all_versions[i]).length()))/2, ' ') << "|\t";
+  }
+  ret << std::endl;
+  for (int i = 0; i < indexer; i++) {
+    its[i] = all_maps[i].begin();
+    ret << "|" << string((25 - (string("unwritable? ").length()
+	+ 1))/2, ' ');
+    ret << "unwritable? " << string(all_unwrit[i].c_str(),
+	all_unwrit[i].length());
+    ret << string((25 - (string("unwritable? ").length()
+	  + 1))/2, ' ') << "|\t";
+  }
+  ret << std::endl;
+  for (int i = 0; i < indexer; i++) {
+    ret << "---------------------------\t";
+  }
+  ret << std::endl;
+  ret << "///////////////////THE ACTUAL BLOCKS////////////////" << std::endl;
+
+
+  ret << std::endl;
+  for (int i = 0; i < indexer; i++) {
+    ret << "---------------------------\t";
+  }
+  ret << std::endl;
+  //each time through this part is two lines
+  while(done < keys.size()) {
+    for(int i = 0; i < indexer; i++) {
+      if(dones[i]){
+	ret << "                          \t";
+      } else {
+	if (its[i] == all_maps[i].end()){
+	  done++;
+	  dones[i] = true;
+	  ret << "                          \t";
+	} else {
+	  ret << "|" << string((25 -
+	      ((*its[i]).first.length()+its[i]->second.length()+3))/2,' ');
+	  ret << (*its[i]).first;
+	  ret << " | ";
+	  ret << string(its[i]->second.c_str(), its[i]->second.length());
+	  ret << string((25 -
+	      ((*its[i]).first.length()+its[i]->second.length()+3))/2,' ');
+	  ret << "|\t";
+	  ++(its[i]);
+	}
+
+      }
+    }
+    ret << std::endl;
+    for (int i = 0; i < indexer; i++) {
+      if(dones[i]){
+	ret << "                          \t";
+      } else {
+	ret << "---------------------------\t";
+      }
+    }
+    ret << std::endl;
+
+  }
+  return ret.str();
+}