ceph/src/rgw/rgw_aio.h

   1 // -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
   2 // vim: ts=8 sw=2 smarttab ft=cpp
   3
   4 /*
   5  * Ceph - scalable distributed file system
   6  *
   7  * Copyright (C) 2018 Red Hat, Inc.
   8  *
   9  * This is free software; you can redistribute it and/or
  10  * modify it under the terms of the GNU Lesser General Public
  11  * License version 2.1, as published by the Free Software
  12  * Foundation. See file COPYING.
  13  *
  14  */
  15
  16 #pragma once
  17
  18 #include <cstdint>
  19 #include <memory>
  20 #include <type_traits>
  21
  22 #include <boost/intrusive/list.hpp>
  23 #include "include/rados/librados_fwd.hpp"
  24 #include "common/async/yield_context.h"
  25
  26 #include "services/svc_rados.h" // cant forward declare RGWSI_RADOS::Obj
  27
  28 #include "rgw_common.h"
  29
  30 #include "include/function2.hpp"
  31
  32 struct D3nGetObjData;
  33
  34 namespace rgw {
  35
  36 struct AioResult {
  37   RGWSI_RADOS::Obj obj;
  38   uint64_t id = 0; // id allows caller to associate a result with its request
  39   bufferlist data; // result buffer for reads
  40   int result = 0;
  41   std::aligned_storage_t<3 * sizeof(void*)> user_data;
  42
  43   AioResult() = default;
  44   AioResult(const AioResult&) = delete;
  45   AioResult& operator =(const AioResult&) = delete;
  46   AioResult(AioResult&&) = delete;
  47   AioResult& operator =(AioResult&&) = delete;
  48 };
  49 struct AioResultEntry : AioResult, boost::intrusive::list_base_hook<> {
  50   virtual ~AioResultEntry() {}
  51 };
  52 // a list of polymorphic entries that frees them on destruction
  53 template <typename T, typename ...Args>
  54 struct OwningList : boost::intrusive::list<T, Args...> {
  55   OwningList() = default;
  56   ~OwningList() { this->clear_and_dispose(std::default_delete<T>{}); }
  57   OwningList(OwningList&&) = default;
  58   OwningList& operator=(OwningList&&) = default;
  59   OwningList(const OwningList&) = delete;
  60   OwningList& operator=(const OwningList&) = delete;
  61 };
  62 using AioResultList = OwningList<AioResultEntry>;
  63
  64 // returns the first error code or 0 if all succeeded
  65 inline int check_for_errors(const AioResultList& results) {
  66   for (auto& e : results) {
  67     if (e.result < 0) {
  68       return e.result;
  69     }
  70   }
  71   return 0;
  72 }
  73
  74 // interface to submit async librados operations and wait on their completions.
  75 // each call returns a list of results from prior completions
  76 class Aio {
  77  public:
  78   using OpFunc = fu2::unique_function<void(Aio*, AioResult&) &&>;
  79
  80   virtual ~Aio() {}
  81
  82   virtual AioResultList get(const RGWSI_RADOS::Obj& obj,
  83                             OpFunc&& f,
  84                             uint64_t cost, uint64_t id) = 0;
  85   virtual void put(AioResult& r) = 0;
  86
  87   // poll for any ready completions without waiting
  88   virtual AioResultList poll() = 0;
  89
  90   // return any ready completions. if there are none, wait for the next
  91   virtual AioResultList wait() = 0;
  92
  93   // wait for all outstanding completions and return their results
  94   virtual AioResultList drain() = 0;
  95
  96   static OpFunc librados_op(librados::ObjectReadOperation&& op,
  97                             optional_yield y);
  98   static OpFunc librados_op(librados::ObjectWriteOperation&& op,
  99                             optional_yield y);
 100   static OpFunc d3n_cache_op(const DoutPrefixProvider *dpp, optional_yield y,
 101                              off_t read_ofs, off_t read_len, std::string& location);
 102 };
 103
 104 } // namespace rgw