ceph/src/librbd/io/ImageRequestWQ.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_IO_IMAGE_REQUEST_WQ_H
   5 #define CEPH_LIBRBD_IO_IMAGE_REQUEST_WQ_H
   6
   7 #include "include/Context.h"
   8 #include "common/RWLock.h"
   9 #include "common/WorkQueue.h"
  10 #include "librbd/io/Types.h"
  11
  12 #include <list>
  13 #include <atomic>
  14
  15 namespace librbd {
  16
  17 class ImageCtx;
  18
  19 namespace io {
  20
  21 class AioCompletion;
  22 template <typename> class ImageRequest;
  23 class ReadResult;
  24
  25 template <typename ImageCtxT = librbd::ImageCtx>
  26 class ImageRequestWQ
  27   : public ThreadPool::PointerWQ<ImageRequest<ImageCtxT> > {
  28 public:
  29   ImageRequestWQ(ImageCtxT *image_ctx, const string &name, time_t ti,
  30                  ThreadPool *tp);
  31
  32   ssize_t read(uint64_t off, uint64_t len, ReadResult &&read_result,
  33                int op_flags);
  34   ssize_t write(uint64_t off, uint64_t len, bufferlist &&bl, int op_flags);
  35   ssize_t discard(uint64_t off, uint64_t len, bool skip_partial_discard);
  36   ssize_t writesame(uint64_t off, uint64_t len, bufferlist &&bl, int op_flags);
  37
  38   void aio_read(AioCompletion *c, uint64_t off, uint64_t len,
  39                 ReadResult &&read_result, int op_flags, bool native_async=true);
  40   void aio_write(AioCompletion *c, uint64_t off, uint64_t len,
  41                  bufferlist &&bl, int op_flags, bool native_async=true);
  42   void aio_discard(AioCompletion *c, uint64_t off, uint64_t len,
  43                    bool skip_partial_discard, bool native_async=true);
  44   void aio_flush(AioCompletion *c, bool native_async=true);
  45   void aio_writesame(AioCompletion *c, uint64_t off, uint64_t len,
  46                      bufferlist &&bl, int op_flags, bool native_async=true);
  47
  48   using ThreadPool::PointerWQ<ImageRequest<ImageCtxT> >::drain;
  49
  50   using ThreadPool::PointerWQ<ImageRequest<ImageCtxT> >::empty;
  51
  52   void shut_down(Context *on_shutdown);
  53
  54   inline bool writes_blocked() const {
  55     RWLock::RLocker locker(m_lock);
  56     return (m_write_blockers > 0);
  57   }
  58
  59   int block_writes();
  60   void block_writes(Context *on_blocked);
  61   void unblock_writes();
  62
  63   void set_require_lock(Direction direction, bool enabled);
  64
  65 protected:
  66   void *_void_dequeue() override;
  67   void process(ImageRequest<ImageCtxT> *req) override;
  68
  69 private:
  70   typedef std::list<Context *> Contexts;
  71
  72   struct C_AcquireLock;
  73   struct C_BlockedWrites;
  74   struct C_RefreshFinish;
  75
  76   ImageCtxT &m_image_ctx;
  77   mutable RWLock m_lock;
  78   Contexts m_write_blocker_contexts;
  79   uint32_t m_write_blockers = 0;
  80   bool m_require_lock_on_read = false;
  81   bool m_require_lock_on_write = false;
  82   std::atomic<unsigned> m_queued_reads { 0 };
  83   std::atomic<unsigned> m_queued_writes { 0 };
  84   std::atomic<unsigned> m_in_flight_ios { 0 };
  85   std::atomic<unsigned> m_in_flight_writes { 0 };
  86   std::atomic<unsigned> m_io_blockers { 0 };
  87
  88   bool m_shutdown = false;
  89   Context *m_on_shutdown = nullptr;
  90
  91   bool is_lock_required(bool write_op) const;
  92
  93   inline bool require_lock_on_read() const {
  94     RWLock::RLocker locker(m_lock);
  95     return m_require_lock_on_read;
  96   }
  97   inline bool writes_empty() const {
  98     RWLock::RLocker locker(m_lock);
  99     return (m_queued_writes == 0);
 100   }
 101
 102   void finish_queued_io(ImageRequest<ImageCtxT> *req);
 103   void finish_in_flight_write();
 104
 105   int start_in_flight_io(AioCompletion *c);
 106   void finish_in_flight_io();
 107   void fail_in_flight_io(int r, ImageRequest<ImageCtxT> *req);
 108
 109   void queue(ImageRequest<ImageCtxT> *req);
 110
 111   void handle_acquire_lock(int r, ImageRequest<ImageCtxT> *req);
 112   void handle_refreshed(int r, ImageRequest<ImageCtxT> *req);
 113   void handle_blocked_writes(int r);
 114 };
 115
 116 } // namespace io
 117 } // namespace librbd
 118
 119 extern template class librbd::io::ImageRequestWQ<librbd::ImageCtx>;
 120
 121 #endif // CEPH_LIBRBD_IO_IMAGE_REQUEST_WQ_H