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diff --git a/src/ceph/src/common/Cond.h b/src/ceph/src/common/Cond.h
new file mode 100644
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+++ b/src/ceph/src/common/Cond.h
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+// -*- 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>
+ *
+ * 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.
+ *
+ */
+
+
+#ifndef CEPH_COND_H
+#define CEPH_COND_H
+
+#include "include/Context.h"
+
+class Cond {
+  // my bits
+  pthread_cond_t _c;
+
+  Mutex *waiter_mutex;
+
+  // don't allow copying.
+  void operator=(Cond &C);
+  Cond(const Cond &C);
+
+ public:
+  Cond() : waiter_mutex(NULL) {
+    int r = pthread_cond_init(&_c,NULL);
+    assert(r == 0);
+  }
+  virtual ~Cond() { 
+    pthread_cond_destroy(&_c); 
+  }
+
+  int Wait(Mutex &mutex)  { 
+    // make sure this cond is used with one mutex only
+    assert(waiter_mutex == NULL || waiter_mutex == &mutex);
+    waiter_mutex = &mutex;
+
+    assert(mutex.is_locked());
+
+    mutex._pre_unlock();
+    int r = pthread_cond_wait(&_c, &mutex._m);
+    mutex._post_lock();
+    return r;
+  }
+
+  int WaitUntil(Mutex &mutex, utime_t when) {
+    // make sure this cond is used with one mutex only
+    assert(waiter_mutex == NULL || waiter_mutex == &mutex);
+    waiter_mutex = &mutex;
+
+    assert(mutex.is_locked());
+
+    struct timespec ts;
+    when.to_timespec(&ts);
+
+    mutex._pre_unlock();
+    int r = pthread_cond_timedwait(&_c, &mutex._m, &ts);
+    mutex._post_lock();
+
+    return r;
+  }
+
+  int WaitInterval(Mutex &mutex, utime_t interval) {
+    utime_t when = ceph_clock_now();
+    when += interval;
+    return WaitUntil(mutex, when);
+  }
+
+  template<typename Duration>
+  int WaitInterval(Mutex &mutex, Duration interval) {
+    ceph::real_time when(ceph::real_clock::now());
+    when += interval;
+
+    struct timespec ts = ceph::real_clock::to_timespec(when);
+
+    mutex._pre_unlock();
+    int r = pthread_cond_timedwait(&_c, &mutex._m, &ts);
+    mutex._post_lock();
+
+    return r;
+  }
+
+  int SloppySignal() { 
+    int r = pthread_cond_broadcast(&_c);
+    return r;
+  }
+  int Signal() { 
+    // make sure signaler is holding the waiter's lock.
+    assert(waiter_mutex == NULL ||
+	   waiter_mutex->is_locked());
+
+    int r = pthread_cond_broadcast(&_c);
+    return r;
+  }
+  int SignalOne() { 
+    // make sure signaler is holding the waiter's lock.
+    assert(waiter_mutex == NULL ||
+	   waiter_mutex->is_locked());
+
+    int r = pthread_cond_signal(&_c);
+    return r;
+  }
+  int SignalAll() { 
+    // make sure signaler is holding the waiter's lock.
+    assert(waiter_mutex == NULL ||
+	   waiter_mutex->is_locked());
+
+    int r = pthread_cond_broadcast(&_c);
+    return r;
+  }
+};
+
+/**
+ * context to signal a cond
+ *
+ * Generic context to signal a cond and store the return value.  We
+ * assume the caller is holding the appropriate lock.
+ */
+class C_Cond : public Context {
+  Cond *cond;   ///< Cond to signal
+  bool *done;   ///< true if finish() has been called
+  int *rval;    ///< return value
+public:
+  C_Cond(Cond *c, bool *d, int *r) : cond(c), done(d), rval(r) {
+    *done = false;
+  }
+  void finish(int r) override {
+    *done = true;
+    *rval = r;
+    cond->Signal();
+  }
+};
+
+/**
+ * context to signal a cond, protected by a lock
+ *
+ * Generic context to signal a cond under a specific lock. We take the
+ * lock in the finish() callback, so the finish() caller must not
+ * already hold it.
+ */
+class C_SafeCond : public Context {
+  Mutex *lock;    ///< Mutex to take
+  Cond *cond;     ///< Cond to signal
+  bool *done;     ///< true after finish() has been called
+  int *rval;      ///< return value (optional)
+public:
+  C_SafeCond(Mutex *l, Cond *c, bool *d, int *r=0) : lock(l), cond(c), done(d), rval(r) {
+    *done = false;
+  }
+  void finish(int r) override {
+    lock->Lock();
+    if (rval)
+      *rval = r;
+    *done = true;
+    cond->Signal();
+    lock->Unlock();
+  }
+};
+
+/**
+ * Context providing a simple wait() mechanism to wait for completion
+ *
+ * The context will not be deleted as part of complete and must live
+ * until wait() returns.
+ */
+class C_SaferCond : public Context {
+  Mutex lock;    ///< Mutex to take
+  Cond cond;     ///< Cond to signal
+  bool done;     ///< true after finish() has been called
+  int rval;      ///< return value
+public:
+  C_SaferCond() : lock("C_SaferCond"), done(false), rval(0) {}
+  void finish(int r) override { complete(r); }
+
+  /// We overload complete in order to not delete the context
+  void complete(int r) override {
+    Mutex::Locker l(lock);
+    done = true;
+    rval = r;
+    cond.Signal();
+  }
+
+  /// Returns rval once the Context is called
+  int wait() {
+    Mutex::Locker l(lock);
+    while (!done)
+      cond.Wait(lock);
+    return rval;
+  }
+};
+
+#endif