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diff --git a/src/ceph/src/librbd/io/AioCompletion.h b/src/ceph/src/librbd/io/AioCompletion.h
new file mode 100644
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+++ b/src/ceph/src/librbd/io/AioCompletion.h
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+// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
+// vim: ts=8 sw=2 smarttab
+
+#ifndef CEPH_LIBRBD_IO_AIO_COMPLETION_H
+#define CEPH_LIBRBD_IO_AIO_COMPLETION_H
+
+#include "common/Cond.h"
+#include "common/Mutex.h"
+#include "include/Context.h"
+#include "include/utime.h"
+#include "include/rbd/librbd.hpp"
+
+#include "librbd/ImageCtx.h"
+#include "librbd/io/AsyncOperation.h"
+#include "librbd/io/ReadResult.h"
+#include "librbd/io/Types.h"
+
+class CephContext;
+
+namespace librbd {
+namespace io {
+
+
+/**
+ * AioCompletion is the overall completion for a single
+ * rbd I/O request. It may be composed of many AioObjectRequests,
+ * which each go to a single object.
+ *
+ * The retrying of individual requests is handled at a lower level,
+ * so all AioCompletion cares about is the count of outstanding
+ * requests. The number of expected individual requests should be
+ * set initially using set_request_count() prior to issuing the
+ * requests.  This ensures that the completion will not be completed
+ * within the caller's thread of execution (instead via a librados
+ * context or via a thread pool context for cache read hits).
+ */
+struct AioCompletion {
+  typedef enum {
+    AIO_STATE_PENDING = 0,
+    AIO_STATE_CALLBACK,
+    AIO_STATE_COMPLETE,
+  } aio_state_t;
+
+  mutable Mutex lock;
+  Cond cond;
+  aio_state_t state;
+  ssize_t rval;
+  callback_t complete_cb;
+  void *complete_arg;
+  rbd_completion_t rbd_comp;
+  uint32_t pending_count;   ///< number of requests
+  uint32_t blockers;
+  int ref;
+  bool released;
+  ImageCtx *ictx;
+  utime_t start_time;
+  aio_type_t aio_type;
+
+  ReadResult read_result;
+
+  AsyncOperation async_op;
+
+  uint64_t journal_tid;
+  xlist<AioCompletion*>::item m_xlist_item;
+  bool event_notify;
+
+  template <typename T, void (T::*MF)(int)>
+  static void callback_adapter(completion_t cb, void *arg) {
+    AioCompletion *comp = reinterpret_cast<AioCompletion *>(cb);
+    T *t = reinterpret_cast<T *>(arg);
+    (t->*MF)(comp->get_return_value());
+    comp->release();
+  }
+
+  static AioCompletion *create(void *cb_arg, callback_t cb_complete,
+                               rbd_completion_t rbd_comp) {
+    AioCompletion *comp = new AioCompletion();
+    comp->set_complete_cb(cb_arg, cb_complete);
+    comp->rbd_comp = (rbd_comp != nullptr ? rbd_comp : comp);
+    return comp;
+  }
+
+  template <typename T, void (T::*MF)(int) = &T::complete>
+  static AioCompletion *create(T *obj) {
+    AioCompletion *comp = new AioCompletion();
+    comp->set_complete_cb(obj, &callback_adapter<T, MF>);
+    comp->rbd_comp = comp;
+    return comp;
+  }
+
+  template <typename T, void (T::*MF)(int) = &T::complete>
+  static AioCompletion *create_and_start(T *obj, ImageCtx *image_ctx,
+                                         aio_type_t type) {
+    AioCompletion *comp = create<T, MF>(obj);
+    comp->init_time(image_ctx, type);
+    comp->start_op();
+    return comp;
+  }
+
+  AioCompletion() : lock("AioCompletion::lock", true, false),
+                    state(AIO_STATE_PENDING), rval(0), complete_cb(NULL),
+                    complete_arg(NULL), rbd_comp(NULL),
+                    pending_count(0), blockers(1),
+                    ref(1), released(false), ictx(NULL),
+                    aio_type(AIO_TYPE_NONE),
+                    journal_tid(0), m_xlist_item(this), event_notify(false) {
+  }
+
+  ~AioCompletion() {
+  }
+
+  int wait_for_complete();
+
+  void finalize(ssize_t rval);
+
+  inline bool is_initialized(aio_type_t type) const {
+    Mutex::Locker locker(lock);
+    return ((ictx != nullptr) && (aio_type == type));
+  }
+  inline bool is_started() const {
+    Mutex::Locker locker(lock);
+    return async_op.started();
+  }
+
+  void init_time(ImageCtx *i, aio_type_t t);
+  void start_op(bool ignore_type = false);
+  void fail(int r);
+
+  void complete();
+
+  void set_complete_cb(void *cb_arg, callback_t cb) {
+    complete_cb = cb;
+    complete_arg = cb_arg;
+  }
+
+  void set_request_count(uint32_t num);
+  void add_request() {
+    lock.Lock();
+    assert(pending_count > 0);
+    lock.Unlock();
+    get();
+  }
+  void complete_request(ssize_t r);
+
+  void associate_journal_event(uint64_t tid);
+
+  bool is_complete();
+
+  ssize_t get_return_value();
+
+  void get() {
+    lock.Lock();
+    assert(ref > 0);
+    ref++;
+    lock.Unlock();
+  }
+  void release() {
+    lock.Lock();
+    assert(!released);
+    released = true;
+    put_unlock();
+  }
+  void put() {
+    lock.Lock();
+    put_unlock();
+  }
+  void put_unlock() {
+    assert(ref > 0);
+    int n = --ref;
+    lock.Unlock();
+    if (!n) {
+      if (ictx) {
+        if (event_notify) {
+          ictx->completed_reqs_lock.Lock();
+          m_xlist_item.remove_myself();
+          ictx->completed_reqs_lock.Unlock();
+        }
+        if (aio_type == AIO_TYPE_CLOSE ||
+            (aio_type == AIO_TYPE_OPEN && rval < 0)) {
+          delete ictx;
+        }
+      }
+      delete this;
+    }
+  }
+
+  void block() {
+    Mutex::Locker l(lock);
+    ++blockers;
+  }
+  void unblock() {
+    Mutex::Locker l(lock);
+    assert(blockers > 0);
+    --blockers;
+    if (pending_count == 0 && blockers == 0) {
+      finalize(rval);
+      complete();
+    }
+  }
+
+  void set_event_notify(bool s) {
+    Mutex::Locker l(lock);
+    event_notify = s;
+  }
+
+  void *get_arg() {
+    return complete_arg;
+  }
+};
+
+class C_AioRequest : public Context {
+public:
+  C_AioRequest(AioCompletion *completion) : m_completion(completion) {
+    m_completion->add_request();
+  }
+  ~C_AioRequest() override {}
+  void finish(int r) override {
+    m_completion->complete_request(r);
+  }
+protected:
+  AioCompletion *m_completion;
+};
+
+} // namespace io
+} // namespace librbd
+
+#endif // CEPH_LIBRBD_IO_AIO_COMPLETION_H