1 files changed, 104 insertions, 0 deletions
diff --git a/src/crimson/osd/pg_meta.cc b/src/crimson/osd/pg_meta.cc
new file mode 100644
index 00000000..2098e50a
--- /dev/null
+++ b/src/crimson/osd/pg_meta.cc
@@ -0,0 +1,104 @@
+#include "pg_meta.h"
+
+#include <string_view>
+
+#include "crimson/os/cyan_collection.h"
+#include "crimson/os/cyan_store.h"
+
+// prefix pgmeta_oid keys with _ so that PGLog::read_log_and_missing() can
+// easily skip them
+
+static const string_view infover_key = "_infover"sv;
+static const string_view info_key = "_info"sv;
+static const string_view biginfo_key = "_biginfo"sv;
+static const string_view epoch_key = "_epoch"sv;
+static const string_view fastinfo_key = "_fastinfo"sv;
+
+using ceph::os::CyanStore;
+
+PGMeta::PGMeta(CyanStore* store, spg_t pgid)
+  : store{store},
+    pgid{pgid}
+{}
+
+namespace {
+  template<typename T>
+  std::optional<T> find_value(const CyanStore::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()
+{
+  auto ch = store->open_collection(coll_t{pgid});
+  return store->omap_get_values(ch,
+                                pgid.make_pgmeta_oid(),
+                                {string{infover_key},
+                                 string{epoch_key}}).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);
+      }
+    });
+}
+
+seastar::future<pg_info_t, PastIntervals> PGMeta::load()
+{
+  auto ch = store->open_collection(coll_t{pgid});
+  return store->omap_get_values(ch,
+                                pgid.make_pgmeta_oid(),
+                                {string{infover_key},
+                                 string{info_key},
+                                 string{biginfo_key},
+                                 string{fastinfo_key}}).then(
+    [this](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);
+        assert(fast_info);
+        fast_info->try_apply_to(&info);
+      }
+      return seastar::make_ready_future<pg_info_t, PastIntervals>(
+        std::move(info),
+        std::move(past_intervals));
+    });
+}