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 "common/AsyncOpTracker.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 = nullptr) const;
  22   bool accept_ops() const;
  23
  24   void block_requests(int r);
  25   void unblock_requests();
  26
  27   void init(uint64_t features, Context *on_init);
  28   void shut_down(Context *on_shutdown);
  29
  30   void handle_peer_notification(int r);
  31
  32   Context *start_op();
  33
  34 protected:
  35   void shutdown_handler(int r, Context *on_finish) override;
  36   void pre_acquire_lock_handler(Context *on_finish) override;
  37   void post_acquire_lock_handler(int r, Context *on_finish) override;
  38   void pre_release_lock_handler(bool shutting_down,
  39                                 Context *on_finish) override;
  40   void post_release_lock_handler(bool shutting_down, int r,
  41                                  Context *on_finish) override;
  42   void post_reacquire_lock_handler(int r, Context *on_finish) override;
  43
  44 private:
  45
  46   /**
  47    * @verbatim
  48    *
  49    * <start>                              * * > WAITING_FOR_REGISTER --------\
  50    *    |                                 * (watch not registered)           |
  51    *    |                                 *                                  |
  52    *    |                                 * * > WAITING_FOR_PEER ------------\
  53    *    |                                 * (request_lock busy)              |
  54    *    |                                 *                                  |
  55    *    |                                 * * * * * * * * * * * * * *        |
  56    *    |                                                           *        |
  57    *    v            (init)            (try_lock/request_lock)      *        |
  58    * UNINITIALIZED  -------> UNLOCKED ------------------------> ACQUIRING <--/
  59    *                            ^                                   |
  60    *                            |                                   v
  61    *                         RELEASING                        POST_ACQUIRING
  62    *                            |                                   |
  63    *                            |                                   |
  64    *                            |          (release_lock)           v
  65    *                      PRE_RELEASING <------------------------ LOCKED
  66    *
  67    * <LOCKED state>
  68    *    |
  69    *    v
  70    * REACQUIRING -------------------------------------> <finish>
  71    *    .                                                 ^
  72    *    .                                                 |
  73    *    . . . > <RELEASE action> ---> <ACQUIRE action> ---/
  74    *
  75    * <UNLOCKED/LOCKED states>
  76    *    |
  77    *    |
  78    *    v
  79    * PRE_SHUTTING_DOWN ---> SHUTTING_DOWN ---> SHUTDOWN ---> <finish>
  80    *
  81    * @endverbatim
  82    */
  83
  84   struct C_InitComplete;
  85
  86   ImageCtxT& m_image_ctx;
  87   Context *m_pre_post_callback = nullptr;
  88
  89   AsyncOpTracker m_async_op_tracker;
  90
  91   uint32_t m_request_blocked_count = 0;
  92   int m_request_blocked_ret_val = 0;
  93
  94   int m_acquire_lock_peer_ret_val = 0;
  95
  96   bool accept_ops(const Mutex &lock) const;
  97
  98   void handle_init_complete(uint64_t features);
  99   void handle_post_acquiring_lock(int r);
 100   void handle_post_acquired_lock(int r);
 101 };
 102
 103 } // namespace librbd
 104
 105 #endif // CEPH_LIBRBD_EXCLUSIVE_LOCK_H