1 files changed, 104 insertions, 0 deletions
diff --git a/src/rgw/rgw_aio.h b/src/rgw/rgw_aio.h
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+++ b/src/rgw/rgw_aio.h
@@ -0,0 +1,104 @@
+// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
+// vim: ts=8 sw=2 smarttab ft=cpp
+
+/*
+ * Ceph - scalable distributed file system
+ *
+ * Copyright (C) 2018 Red Hat, Inc.
+ *
+ * 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.
+ *
+ */
+
+#pragma once
+
+#include <cstdint>
+#include <memory>
+#include <type_traits>
+
+#include <boost/intrusive/list.hpp>
+#include "include/rados/librados_fwd.hpp"
+#include "common/async/yield_context.h"
+
+#include "services/svc_rados.h" // cant forward declare RGWSI_RADOS::Obj
+
+#include "rgw_common.h"
+
+#include "include/function2.hpp"
+
+struct D3nGetObjData;
+
+namespace rgw {
+
+struct AioResult {
+  RGWSI_RADOS::Obj obj;
+  uint64_t id = 0; // id allows caller to associate a result with its request
+  bufferlist data; // result buffer for reads
+  int result = 0;
+  std::aligned_storage_t<3 * sizeof(void*)> user_data;
+
+  AioResult() = default;
+  AioResult(const AioResult&) = delete;
+  AioResult& operator =(const AioResult&) = delete;
+  AioResult(AioResult&&) = delete;
+  AioResult& operator =(AioResult&&) = delete;
+};
+struct AioResultEntry : AioResult, boost::intrusive::list_base_hook<> {
+  virtual ~AioResultEntry() {}
+};
+// a list of polymorphic entries that frees them on destruction
+template <typename T, typename ...Args>
+struct OwningList : boost::intrusive::list<T, Args...> {
+  OwningList() = default;
+  ~OwningList() { this->clear_and_dispose(std::default_delete<T>{}); }
+  OwningList(OwningList&&) = default;
+  OwningList& operator=(OwningList&&) = default;
+  OwningList(const OwningList&) = delete;
+  OwningList& operator=(const OwningList&) = delete;
+};
+using AioResultList = OwningList<AioResultEntry>;
+
+// returns the first error code or 0 if all succeeded
+inline int check_for_errors(const AioResultList& results) {
+  for (auto& e : results) {
+    if (e.result < 0) {
+      return e.result;
+    }
+  }
+  return 0;
+}
+
+// interface to submit async librados operations and wait on their completions.
+// each call returns a list of results from prior completions
+class Aio {
+ public:
+  using OpFunc = fu2::unique_function<void(Aio*, AioResult&) &&>;
+
+  virtual ~Aio() {}
+
+  virtual AioResultList get(const RGWSI_RADOS::Obj& obj,
+			    OpFunc&& f,
+			    uint64_t cost, uint64_t id) = 0;
+  virtual void put(AioResult& r) = 0;
+
+  // poll for any ready completions without waiting
+  virtual AioResultList poll() = 0;
+
+  // return any ready completions. if there are none, wait for the next
+  virtual AioResultList wait() = 0;
+
+  // wait for all outstanding completions and return their results
+  virtual AioResultList drain() = 0;
+
+  static OpFunc librados_op(librados::ObjectReadOperation&& op,
+                            optional_yield y);
+  static OpFunc librados_op(librados::ObjectWriteOperation&& op,
+                            optional_yield y);
+  static OpFunc d3n_cache_op(const DoutPrefixProvider *dpp, optional_yield y,
+                             off_t read_ofs, off_t read_len, std::string& location);
+};
+
+} // namespace rgw