1 files changed, 108 insertions, 0 deletions
diff --git a/src/crimson/osd/pg_meta.cc b/src/crimson/osd/pg_meta.cc
new file mode 100644
index 000000000..ad5385963
--- /dev/null
+++ b/src/crimson/osd/pg_meta.cc
@@ -0,0 +1,108 @@
+// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
+// vim: ts=8 sw=2 smarttab
+
+#include "pg_meta.h"
+
+#include <string_view>
+
+#include "crimson/os/futurized_collection.h"
+#include "crimson/os/futurized_store.h"
+
+// prefix pgmeta_oid keys with _ so that PGLog::read_log_and_missing() can
+// easily skip them
+using crimson::os::FuturizedStore;
+
+PGMeta::PGMeta(FuturizedStore* store, spg_t pgid)
+  : store{store},
+    pgid{pgid}
+{}
+
+namespace {
+  template<typename T>
+  std::optional<T> find_value(const FuturizedStore::omap_values_t& values,
+                              string_view key)
+  {
+    auto found = values.find(key);
+    if (found == values.end()) {
+      return {};
+    }
+    auto p = found->second.cbegin();
+    T value;
+    decode(value, p);
+    return std::make_optional(std::move(value));
+  }
+}
+
+seastar::future<epoch_t> PGMeta::get_epoch()
+{
+  return store->open_collection(coll_t{pgid}).then([this](auto ch) {
+    return store->omap_get_values(ch,
+                                pgid.make_pgmeta_oid(),
+                                {string{infover_key},
+                                 string{epoch_key}}).safe_then(
+    [](auto&& values) {
+      {
+        // sanity check
+        auto infover = find_value<__u8>(values, infover_key);
+        assert(infover);
+        if (*infover < 10) {
+          throw std::runtime_error("incompatible pg meta");
+        }
+      }
+      {
+        auto epoch = find_value<epoch_t>(values, epoch_key);
+        assert(epoch);
+        return seastar::make_ready_future<epoch_t>(*epoch);
+      }
+    },
+    FuturizedStore::read_errorator::assert_all{
+      "PGMeta::get_epoch: unable to read pgmeta"
+    });
+  });
+}
+
+seastar::future<std::tuple<pg_info_t, PastIntervals>> PGMeta::load()
+{
+  return store->open_collection(coll_t{pgid}).then([this](auto ch) {
+    return store->omap_get_values(ch,
+                                pgid.make_pgmeta_oid(),
+                                {string{infover_key},
+                                 string{info_key},
+                                 string{biginfo_key},
+                                 string{fastinfo_key}});
+  }).safe_then([](auto&& values) {
+    {
+      // sanity check
+      auto infover = find_value<__u8>(values, infover_key);
+      assert(infover);
+      if (infover < 10) {
+        throw std::runtime_error("incompatible pg meta");
+      }
+    }
+    pg_info_t info;
+    {
+      auto found = find_value<pg_info_t>(values, info_key);
+      assert(found);
+      info = *std::move(found);
+    }
+    PastIntervals past_intervals;
+    {
+      using biginfo_t = std::pair<PastIntervals, decltype(info.purged_snaps)>;
+      auto big_info = find_value<biginfo_t>(values, biginfo_key);
+      assert(big_info);
+      past_intervals = std::move(big_info->first);
+      info.purged_snaps = std::move(big_info->second);
+    }
+    {
+      auto fast_info = find_value<pg_fast_info_t>(values, fastinfo_key);
+      if (fast_info) {
+        fast_info->try_apply_to(&info);
+      }
+    }
+    return seastar::make_ready_future<std::tuple<pg_info_t, PastIntervals>>(
+      std::make_tuple(std::move(info), std::move(past_intervals)));
+  },
+  FuturizedStore::read_errorator::assert_all{
+    "PGMeta::load: unable to read pgmeta"
+  });
+}