1 files changed, 143 insertions, 0 deletions
diff --git a/src/crimson/os/seastore/onode_manager/staged-fltree/super.h b/src/crimson/os/seastore/onode_manager/staged-fltree/super.h
new file mode 100644
index 000000000..5eefee9ff
--- /dev/null
+++ b/src/crimson/os/seastore/onode_manager/staged-fltree/super.h
@@ -0,0 +1,143 @@
+// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:nil -*-
+// vim: ts=8 sw=2 smarttab
+
+#pragma once
+
+#include <memory>
+
+#include "crimson/common/type_helpers.h"
+
+#include "fwd.h"
+
+namespace crimson::os::seastore::onode {
+
+class Node;
+class Super;
+
+/**
+ * RootNodeTracker
+ *
+ * An abstracted tracker to get the root node by Transaction.
+ */
+class RootNodeTracker {
+ public:
+  virtual ~RootNodeTracker() = default;
+  virtual bool is_clean() const = 0;
+  virtual Ref<Node> get_root(Transaction&) const = 0;
+  static RootNodeTrackerURef create(bool read_isolated);
+ protected:
+  RootNodeTracker() = default;
+  RootNodeTracker(const RootNodeTracker&) = delete;
+  RootNodeTracker(RootNodeTracker&&) = delete;
+  RootNodeTracker& operator=(const RootNodeTracker&) = delete;
+  RootNodeTracker& operator=(RootNodeTracker&&) = delete;
+  virtual void do_track_super(Transaction&, Super&) = 0;
+  virtual void do_untrack_super(Transaction&, Super&) = 0;
+  friend class Super;
+};
+
+/**
+ * Super
+ *
+ * The parent of root node. It contains the relationship between a Transaction
+ * and a root node address.
+ */
+class Super {
+ public:
+  using URef = std::unique_ptr<Super>;
+  Super(const Super&) = delete;
+  Super(Super&&) = delete;
+  Super& operator=(const Super&) = delete;
+  Super& operator=(Super&&) = delete;
+  virtual ~Super() {
+    assert(tracked_root_node == nullptr);
+    tracker.do_untrack_super(t, *this);
+  }
+
+  virtual laddr_t get_root_laddr() const = 0;
+  virtual void write_root_laddr(context_t, laddr_t) = 0;
+
+  void do_track_root(Node& root) {
+    assert(tracked_root_node == nullptr);
+    tracked_root_node = &root;
+  }
+  void do_untrack_root(Node& root) {
+    assert(tracked_root_node == &root);
+    tracked_root_node = nullptr;
+  }
+  Node* get_p_root() const {
+    assert(tracked_root_node != nullptr);
+    return tracked_root_node;
+  }
+
+ protected:
+  Super(Transaction& t, RootNodeTracker& tracker)
+      : t{t}, tracker{tracker} {
+    tracker.do_track_super(t, *this);
+  }
+
+ private:
+  Transaction& t;
+  RootNodeTracker& tracker;
+  Node* tracked_root_node = nullptr;
+};
+
+/**
+ * RootNodeTrackerIsolated
+ *
+ * A concrete RootNodeTracker implementation which provides root node isolation
+ * between Transactions for Seastore backend.
+ */
+class RootNodeTrackerIsolated final : public RootNodeTracker {
+ public:
+  ~RootNodeTrackerIsolated() override { assert(is_clean()); }
+ protected:
+  bool is_clean() const override {
+    return tracked_supers.empty();
+  }
+  void do_track_super(Transaction& t, Super& super) override {
+    assert(tracked_supers.find(&t) == tracked_supers.end());
+    tracked_supers[&t] = &super;
+  }
+  void do_untrack_super(Transaction& t, Super& super) override {
+    [[maybe_unused]] auto removed = tracked_supers.erase(&t);
+    assert(removed);
+  }
+  ::Ref<Node> get_root(Transaction& t) const override;
+  std::map<Transaction*, Super*> tracked_supers;
+};
+
+/**
+ * RootNodeTrackerShared
+ *
+ * A concrete RootNodeTracker implementation which has no isolation between
+ * Transactions for Dummy backend.
+ */
+class RootNodeTrackerShared final : public RootNodeTracker {
+ public:
+  ~RootNodeTrackerShared() override { assert(is_clean()); }
+ protected:
+  bool is_clean() const override {
+    return tracked_super == nullptr;
+  }
+  void do_track_super(Transaction&, Super& super) override {
+    assert(is_clean());
+    tracked_super = &super;
+  }
+  void do_untrack_super(Transaction&, Super& super) override {
+    assert(tracked_super == &super);
+    tracked_super = nullptr;
+  }
+  ::Ref<Node> get_root(Transaction&) const override;
+  Super* tracked_super = nullptr;
+};
+
+inline RootNodeTrackerURef RootNodeTracker::create(bool read_isolated) {
+  if (read_isolated) {
+    return RootNodeTrackerURef(new RootNodeTrackerIsolated());
+  } else {
+    return RootNodeTrackerURef(new RootNodeTrackerShared());
+  }
+}
+
+}