1 files changed, 85 insertions, 0 deletions
diff --git a/src/librbd/object_map/SnapshotRemoveRequest.h b/src/librbd/object_map/SnapshotRemoveRequest.h
new file mode 100644
index 00000000..bd020d1a
--- /dev/null
+++ b/src/librbd/object_map/SnapshotRemoveRequest.h
@@ -0,0 +1,85 @@
+// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
+// vim: ts=8 sw=2 smarttab
+
+#ifndef CEPH_LIBRBD_OBJECT_MAP_SNAPSHOT_REMOVE_REQUEST_H
+#define CEPH_LIBRBD_OBJECT_MAP_SNAPSHOT_REMOVE_REQUEST_H
+
+#include "include/int_types.h"
+#include "include/buffer.h"
+#include "common/bit_vector.hpp"
+#include "librbd/AsyncRequest.h"
+
+namespace librbd {
+namespace object_map {
+
+class SnapshotRemoveRequest : public AsyncRequest<> {
+public:
+  /**
+   * Snapshot rollback goes through the following state machine:
+   *
+   * @verbatim
+   *
+   * <start> -----------> STATE_LOAD_MAP ----\
+   *    .                      *             |
+   *    .                      * (error)     |
+   *    . (invalid object map) v             |
+   *    . . . > STATE_INVALIDATE_NEXT_MAP    |
+   *    .                      |             |
+   *    .                      |             |
+   *    . (fast diff disabled) v             v
+   *    . . . . . . . . . . > STATE_REMOVE_MAP
+   *                                 |
+   *                                 v
+   *                             <finish>
+   *
+   * @endverbatim
+   *
+   * The _LOAD_MAP state is skipped if the fast diff feature is disabled.
+   * If the fast diff feature is enabled and the snapshot is flagged as
+   * invalid, the next snapshot / HEAD object mapis flagged as invalid;
+   * otherwise, the state machine proceeds to remove the object map.
+   */
+
+  SnapshotRemoveRequest(ImageCtx &image_ctx, ceph::BitVector<2> *object_map,
+                        uint64_t snap_id, Context *on_finish)
+    : AsyncRequest(image_ctx, on_finish), m_object_map(*object_map),
+      m_snap_id(snap_id), m_next_snap_id(CEPH_NOSNAP) {
+  }
+
+  void send() override;
+
+protected:
+  bool should_complete(int r) override {
+    return true;
+  }
+
+private:
+  ceph::BitVector<2> &m_object_map;
+  uint64_t m_snap_id;
+  uint64_t m_next_snap_id;
+
+  uint64_t m_flags = 0;
+
+  ceph::BitVector<2> m_snap_object_map;
+  bufferlist m_out_bl;
+
+  void load_map();
+  void handle_load_map(int r);
+
+  void remove_snapshot();
+  void handle_remove_snapshot(int r);
+
+  void invalidate_next_map();
+  void handle_invalidate_next_map(int r);
+
+  void remove_map();
+  void handle_remove_map(int r);
+
+  void compute_next_snap_id();
+  void update_object_map();
+};
+
+} // namespace object_map
+} // namespace librbd
+
+#endif // CEPH_LIBRBD_OBJECT_MAP_SNAPSHOT_REMOVE_REQUEST_H