initial code repo

[stor4nfv.git] / src / ceph / src / librbd / io / CopyupRequest.h

diff --git a/src/ceph/src/librbd/io/CopyupRequest.h b/src/ceph/src/librbd/io/CopyupRequest.h
new file mode 100644 (file)
index 0000000..c4aa6a2
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+++ b/src/ceph/src/librbd/io/CopyupRequest.h
@@ -0,0 +1,110 @@
+// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
+// vim: ts=8 sw=2 smarttab
+
+#ifndef CEPH_LIBRBD_IO_COPYUP_REQUEST_H
+#define CEPH_LIBRBD_IO_COPYUP_REQUEST_H
+
+#include "include/int_types.h"
+#include "include/rados/librados.hpp"
+#include "include/buffer.h"
+#include "common/zipkin_trace.h"
+#include "librbd/io/AsyncOperation.h"
+#include "librbd/io/Types.h"
+
+#include <string>
+#include <vector>
+#include <atomic>
+
+namespace ZTracer { struct Trace; }
+
+namespace librbd {
+
+struct ImageCtx;
+
+namespace io {
+
+struct AioCompletion;
+template <typename I> class ObjectRequest;
+
+class CopyupRequest {
+public:
+  CopyupRequest(ImageCtx *ictx, const std::string &oid, uint64_t objectno,
+                Extents &&image_extents, const ZTracer::Trace &parent_trace);
+  ~CopyupRequest();
+
+  void append_request(ObjectRequest<ImageCtx> *req);
+
+  void send();
+
+  void complete(int r);
+
+private:
+  /**
+   * Copyup requests go through the following state machine to read from the
+   * parent image, update the object map, and copyup the object:
+   *
+   *
+   * @verbatim
+   *
+   *              <start>
+   *                 |
+   *                 v
+   *    . . .STATE_READ_FROM_PARENT. . .
+   *    . .          |                 .
+   *    . .          v                 .
+   *    . .  STATE_OBJECT_MAP_HEAD     v (copy on read /
+   *    . .          |                 .  no HEAD rev. update)
+   *    v v          v                 .
+   *    . .    STATE_OBJECT_MAP. . . . .
+   *    . .          |
+   *    . .          v
+   *    . . . . > STATE_COPYUP
+   *    .            |
+   *    .            v
+   *    . . . . > <finish>
+   *
+   * @endverbatim
+   *
+   * The _OBJECT_MAP state is skipped if the object map isn't enabled or if
+   * an object map update isn't required. The _COPYUP state is skipped if
+   * no data was read from the parent *and* there are no additional ops.
+   */
+  enum State {
+    STATE_READ_FROM_PARENT,
+    STATE_OBJECT_MAP_HEAD, // only update the HEAD revision
+    STATE_OBJECT_MAP,      // update HEAD+snaps (if any)
+    STATE_COPYUP
+  };
+
+  ImageCtx *m_ictx;
+  std::string m_oid;
+  uint64_t m_object_no;
+  Extents m_image_extents;
+  ZTracer::Trace m_trace;
+
+  State m_state;
+  ceph::bufferlist m_copyup_data;
+  std::vector<ObjectRequest<ImageCtx> *> m_pending_requests;
+  std::atomic<unsigned> m_pending_copyups { 0 };
+
+  AsyncOperation m_async_op;
+
+  std::vector<uint64_t> m_snap_ids;
+  librados::IoCtx m_data_ctx; // for empty SnapContext
+
+  void complete_requests(int r);
+
+  bool should_complete(int r);
+
+  void remove_from_list();
+
+  bool send_object_map_head();
+  bool send_object_map();
+  bool send_copyup();
+  bool is_copyup_required();
+};
+
+} // namespace io
+} // namespace librbd
+
+#endif // CEPH_LIBRBD_IO_COPYUP_REQUEST_H