ceph/src/librbd/operation/Request.h

   1 // -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
   2 // vim: ts=8 sw=2 smarttab
   3
   4 #ifndef CEPH_LIBRBD_OPERATION_REQUEST_H
   5 #define CEPH_LIBRBD_OPERATION_REQUEST_H
   6
   7 #include "librbd/AsyncRequest.h"
   8 #include "include/Context.h"
   9 #include "common/RWLock.h"
  10 #include "librbd/Utils.h"
  11 #include "librbd/Journal.h"
  12
  13 namespace librbd {
  14
  15 class ImageCtx;
  16
  17 namespace operation {
  18
  19 template <typename ImageCtxT = ImageCtx>
  20 class Request : public AsyncRequest<ImageCtxT> {
  21 public:
  22   Request(ImageCtxT &image_ctx, Context *on_finish,
  23           uint64_t journal_op_tid = 0);
  24
  25   void send();
  26
  27 protected:
  28   void finish(int r) override;
  29   virtual void send_op() = 0;
  30
  31   virtual bool can_affect_io() const {
  32     return false;
  33   }
  34   virtual journal::Event create_event(uint64_t op_tid) const = 0;
  35
  36   template <typename T, Context*(T::*MF)(int*)>
  37   bool append_op_event(T *request) {
  38     ImageCtxT &image_ctx = this->m_image_ctx;
  39
  40     assert(can_affect_io());
  41     RWLock::RLocker owner_locker(image_ctx.owner_lock);
  42     RWLock::RLocker snap_locker(image_ctx.snap_lock);
  43     if (image_ctx.journal != nullptr) {
  44       if (image_ctx.journal->is_journal_replaying()) {
  45         Context *ctx = util::create_context_callback<T, MF>(request);
  46         replay_op_ready(ctx);
  47         return true;
  48       } else if (image_ctx.journal->is_journal_appending()) {
  49         Context *ctx = util::create_context_callback<T, MF>(request);
  50         append_op_event(ctx);
  51         return true;
  52       }
  53     }
  54     return false;
  55   }
  56
  57   bool append_op_event();
  58
  59   // NOTE: temporary until converted to new state machine format
  60   Context *create_context_finisher(int r);
  61   void finish_and_destroy(int r) override;
  62
  63 private:
  64   struct C_AppendOpEvent : public Context {
  65     Request *request;
  66     Context *on_safe;
  67     C_AppendOpEvent(Request *request, Context *on_safe)
  68       : request(request), on_safe(on_safe) {
  69     }
  70     void finish(int r) override {
  71       if (r >= 0) {
  72         request->m_appended_op_event = true;
  73       }
  74       on_safe->complete(r);
  75     }
  76   };
  77
  78   struct C_CommitOpEvent : public Context {
  79     Request *request;
  80     int ret_val;
  81     C_CommitOpEvent(Request *request, int ret_val)
  82       : request(request), ret_val(ret_val) {
  83     }
  84     void finish(int r) override {
  85       request->handle_commit_op_event(r, ret_val);
  86       delete request;
  87     }
  88   };
  89
  90   uint64_t m_op_tid = 0;
  91   bool m_appended_op_event = false;
  92   bool m_committed_op_event = false;
  93
  94   void replay_op_ready(Context *on_safe);
  95   void append_op_event(Context *on_safe);
  96   void handle_op_event_safe(int r);
  97
  98   bool commit_op_event(int r);
  99   void handle_commit_op_event(int r, int original_ret_val);
 100
 101 };
 102
 103 } // namespace operation
 104 } // namespace librbd
 105
 106 extern template class librbd::operation::Request<librbd::ImageCtx>;
 107
 108 #endif // CEPH_LIBRBD_OPERATION_REQUEST_H