ceph/src/librbd/operation/TrimRequest.h

   1 // -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
   2 // vim: ts=8 sw=2 smarttab
   3 #ifndef CEPH_LIBRBD_OPERATION_TRIM_REQUEST_H
   4 #define CEPH_LIBRBD_OPERATION_TRIM_REQUEST_H
   5
   6 #include "librbd/AsyncRequest.h"
   7
   8 namespace librbd
   9 {
  10
  11 class ImageCtx;
  12 class ProgressContext;
  13
  14 namespace operation {
  15
  16 template <typename ImageCtxT = ImageCtx>
  17 class TrimRequest : public AsyncRequest<ImageCtxT>
  18 {
  19 public:
  20   static TrimRequest *create(ImageCtxT &image_ctx, Context *on_finish,
  21                              uint64_t original_size, uint64_t new_size,
  22                              ProgressContext &prog_ctx) {
  23     return new TrimRequest(image_ctx, on_finish, original_size, new_size,
  24                            prog_ctx);
  25   }
  26
  27   void send() override;
  28
  29 protected:
  30   /**
  31    * Trim goes through the following state machine to remove whole objects,
  32    * clean partially trimmed objects, and update the object map:
  33    *
  34    * @verbatim
  35    *
  36    *     <start> . . . . > STATE_FINISHED . . . . . . . . .
  37    *      |    . . . . . . . . . . > . . . . . . . . .    .
  38    *      |   /                                      .    .
  39    * STATE_PRE_COPYUP ---> STATE_COPYUP_OBJECTS      .    .
  40    *                                |                .    .
  41    *        /-----------------------/                v    .
  42    *        |                                        .    .
  43    *        v                                        .    .
  44    * STATE_POST_COPYUP. . . > .                      .    .
  45    *      |    . . . . . . . . . . < . . . . . . . . .    .
  46    *      |    |              .                           .
  47    *      v    v              v                           .
  48    * STATE_PRE_REMOVE ---> STATE_REMOVE_OBJECTS           .
  49    *                                |   .   .             .
  50    *        /-----------------------/   .   . . . . . .   .
  51    *        |                           .             .   .
  52    *        v                           v             v   v
  53    * STATE_POST_REMOVE --> STATE_CLEAN_BOUNDARY ---> <finish>
  54    *        .                                           ^
  55    *        .                                           .
  56    *        . . . . . . . . . . . . . . . . . . . . . . .
  57    *
  58    * @endverbatim
  59    *
  60    * The _COPYUP_OBJECTS state is skipped if there is no parent overlap
  61    * within the new image size and the image does not have any snapshots.
  62    * The _PRE_REMOVE/_POST_REMOVE states are skipped if the object map
  63    * isn't enabled. The _REMOVE_OBJECTS state is skipped if no whole objects
  64    * are removed.  The _CLEAN_BOUNDARY state is skipped if no boundary
  65    * objects are cleaned.  The state machine will immediately transition
  66    * to _FINISHED state if there are no bytes to trim.
  67    */
  68
  69   enum State {
  70     STATE_PRE_COPYUP,
  71     STATE_COPYUP_OBJECTS,
  72     STATE_POST_COPYUP,
  73     STATE_PRE_REMOVE,
  74     STATE_REMOVE_OBJECTS,
  75     STATE_POST_REMOVE,
  76     STATE_CLEAN_BOUNDARY,
  77     STATE_FINISHED
  78   };
  79
  80   bool should_complete(int r) override;
  81
  82   State m_state;
  83
  84 private:
  85   uint64_t m_delete_start;
  86   uint64_t m_num_objects;
  87   uint64_t m_delete_off;
  88   uint64_t m_new_size;
  89   ProgressContext &m_prog_ctx;
  90
  91   uint64_t m_copyup_start;
  92   uint64_t m_copyup_end;
  93
  94   TrimRequest(ImageCtxT &image_ctx, Context *on_finish,
  95               uint64_t original_size, uint64_t new_size,
  96               ProgressContext &prog_ctx);
  97
  98   void send_pre_copyup();
  99   void send_copyup_objects();
 100   void send_post_copyup();
 101
 102   void send_pre_remove();
 103   void send_remove_objects();
 104   void send_post_remove();
 105
 106   void send_clean_boundary();
 107   void send_finish(int r);
 108 };
 109
 110 } // namespace operation
 111 } // namespace librbd
 112
 113 extern template class librbd::operation::TrimRequest<librbd::ImageCtx>;
 114
 115 #endif // CEPH_LIBRBD_OPERATION_TRIM_REQUEST_H