ceph/src/librbd/ExclusiveLock.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_EXCLUSIVE_LOCK_H
   5 #define CEPH_LIBRBD_EXCLUSIVE_LOCK_H
   6
   7 #include "librbd/ManagedLock.h"
   8 #include "librbd/ImageCtx.h"
   9
  10 namespace librbd {
  11
  12 template <typename ImageCtxT = ImageCtx>
  13 class ExclusiveLock : public ManagedLock<ImageCtxT> {
  14 public:
  15   static ExclusiveLock *create(ImageCtxT &image_ctx) {
  16     return new ExclusiveLock<ImageCtxT>(image_ctx);
  17   }
  18
  19   ExclusiveLock(ImageCtxT &image_ctx);
  20
  21   bool accept_requests(int *ret_val) const;
  22
  23   void block_requests(int r);
  24   void unblock_requests();
  25
  26   void init(uint64_t features, Context *on_init);
  27   void shut_down(Context *on_shutdown);
  28
  29   void handle_peer_notification(int r);
  30
  31 protected:
  32   void shutdown_handler(int r, Context *on_finish) override;
  33   void pre_acquire_lock_handler(Context *on_finish) override;
  34   void post_acquire_lock_handler(int r, Context *on_finish) override;
  35   void pre_release_lock_handler(bool shutting_down,
  36                                 Context *on_finish) override;
  37   void post_release_lock_handler(bool shutting_down, int r,
  38                                  Context *on_finish) override;
  39
  40 private:
  41
  42   /**
  43    * @verbatim
  44    *
  45    * <start>                              * * > WAITING_FOR_REGISTER --------\
  46    *    |                                 * (watch not registered)           |
  47    *    |                                 *                                  |
  48    *    |                                 * * > WAITING_FOR_PEER ------------\
  49    *    |                                 * (request_lock busy)              |
  50    *    |                                 *                                  |
  51    *    |                                 * * * * * * * * * * * * * *        |
  52    *    |                                                           *        |
  53    *    v            (init)            (try_lock/request_lock)      *        |
  54    * UNINITIALIZED  -------> UNLOCKED ------------------------> ACQUIRING <--/
  55    *                            ^                                   |
  56    *                            |                                   v
  57    *                         RELEASING                        POST_ACQUIRING
  58    *                            |                                   |
  59    *                            |                                   |
  60    *                            |          (release_lock)           v
  61    *                      PRE_RELEASING <------------------------ LOCKED
  62    *
  63    * <LOCKED state>
  64    *    |
  65    *    v
  66    * REACQUIRING -------------------------------------> <finish>
  67    *    .                                                 ^
  68    *    .                                                 |
  69    *    . . . > <RELEASE action> ---> <ACQUIRE action> ---/
  70    *
  71    * <UNLOCKED/LOCKED states>
  72    *    |
  73    *    |
  74    *    v
  75    * PRE_SHUTTING_DOWN ---> SHUTTING_DOWN ---> SHUTDOWN ---> <finish>
  76    *
  77    * @endverbatim
  78    */
  79
  80   struct C_InitComplete;
  81
  82   ImageCtxT& m_image_ctx;
  83   Context *m_pre_post_callback = nullptr;
  84
  85   uint32_t m_request_blocked_count = 0;
  86   int m_request_blocked_ret_val = 0;
  87
  88   int m_acquire_lock_peer_ret_val = 0;
  89
  90   void handle_init_complete(uint64_t features);
  91   void handle_post_acquiring_lock(int r);
  92   void handle_post_acquired_lock(int r);
  93 };
  94
  95 } // namespace librbd
  96
  97 #endif // CEPH_LIBRBD_EXCLUSIVE_LOCK_H