1 files changed, 146 insertions, 0 deletions
diff --git a/src/rgw/rgw_bucket_layout.h b/src/rgw/rgw_bucket_layout.h
new file mode 100644
index 000000000..a09215abc
--- /dev/null
+++ b/src/rgw/rgw_bucket_layout.h
@@ -0,0 +1,146 @@
+// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
+// vim: ts=8 sw=2 smarttab ft=cpp
+
+/*
+ * Ceph - scalable distributed file system
+ *
+ * Copyright (C) 2020 Red Hat, Inc.
+ *
+ * This is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License version 2.1, as published by the Free Software
+ * Foundation.  See file COPYING.
+ *
+ */
+
+#pragma once
+
+#include <optional>
+#include <string>
+#include "include/encoding.h"
+
+namespace rgw {
+
+enum class BucketIndexType : uint8_t {
+  Normal, // normal hash-based sharded index layout
+  Indexless, // no bucket index, so listing is unsupported
+};
+
+enum class BucketHashType : uint8_t {
+  Mod, // rjenkins hash of object name, modulo num_shards
+};
+
+inline std::ostream& operator<<(std::ostream& out, const BucketIndexType &index_type)
+{
+  switch (index_type) {
+    case BucketIndexType::Normal:
+      return out << "Normal";
+    case BucketIndexType::Indexless:
+      return out << "Indexless";
+    default:
+      return out << "Unknown";
+  }
+}
+
+struct bucket_index_normal_layout {
+  uint32_t num_shards = 1;
+
+  BucketHashType hash_type = BucketHashType::Mod;
+};
+
+void encode(const bucket_index_normal_layout& l, bufferlist& bl, uint64_t f=0);
+void decode(bucket_index_normal_layout& l, bufferlist::const_iterator& bl);
+
+
+struct bucket_index_layout {
+  BucketIndexType type = BucketIndexType::Normal;
+
+  // TODO: variant of layout types?
+  bucket_index_normal_layout normal;
+};
+
+void encode(const bucket_index_layout& l, bufferlist& bl, uint64_t f=0);
+void decode(bucket_index_layout& l, bufferlist::const_iterator& bl);
+
+
+struct bucket_index_layout_generation {
+  uint64_t gen = 0;
+  bucket_index_layout layout;
+};
+
+void encode(const bucket_index_layout_generation& l, bufferlist& bl, uint64_t f=0);
+void decode(bucket_index_layout_generation& l, bufferlist::const_iterator& bl);
+
+
+enum class BucketLogType : uint8_t {
+  // colocated with bucket index, so the log layout matches the index layout
+  InIndex,
+};
+
+inline std::ostream& operator<<(std::ostream& out, const BucketLogType &log_type)
+{
+  switch (log_type) {
+    case BucketLogType::InIndex:
+      return out << "InIndex";
+    default:
+      return out << "Unknown";
+  }
+}
+
+struct bucket_index_log_layout {
+  uint64_t gen = 0;
+  bucket_index_normal_layout layout;
+};
+
+void encode(const bucket_index_log_layout& l, bufferlist& bl, uint64_t f=0);
+void decode(bucket_index_log_layout& l, bufferlist::const_iterator& bl);
+
+struct bucket_log_layout {
+  BucketLogType type = BucketLogType::InIndex;
+
+  bucket_index_log_layout in_index;
+};
+
+void encode(const bucket_log_layout& l, bufferlist& bl, uint64_t f=0);
+void decode(bucket_log_layout& l, bufferlist::const_iterator& bl);
+
+
+struct bucket_log_layout_generation {
+  uint64_t gen = 0;
+  bucket_log_layout layout;
+};
+
+void encode(const bucket_log_layout_generation& l, bufferlist& bl, uint64_t f=0);
+void decode(bucket_log_layout_generation& l, bufferlist::const_iterator& bl);
+
+// return a log layout that shares its layout with the index
+inline bucket_log_layout_generation log_layout_from_index(
+    uint64_t gen, const bucket_index_normal_layout& index)
+{
+  return {gen, {BucketLogType::InIndex, {gen, index}}};
+}
+
+enum class BucketReshardState : uint8_t {
+  None,
+  InProgress,
+};
+
+// describes the layout of bucket index objects
+struct BucketLayout {
+  BucketReshardState resharding = BucketReshardState::None;
+
+  // current bucket index layout
+  bucket_index_layout_generation current_index;
+
+  // target index layout of a resharding operation
+  std::optional<bucket_index_layout_generation> target_index;
+
+  // history of untrimmed bucket log layout generations, with the current
+  // generation at the back()
+  std::vector<bucket_log_layout_generation> logs;
+};
+
+void encode(const BucketLayout& l, bufferlist& bl, uint64_t f=0);
+void decode(BucketLayout& l, bufferlist::const_iterator& bl);
+
+} // namespace rgw