osd/crimson/pg: support cluster_osdmap_trim_lower_bound()

Signed-off-by: Matan Breizman <mbreizma@redhat.com>

Author: Matan-B

src/crimson/osd/pg.h

@@ -348,8 +348,7 @@ class PG : public boost::intrusive_ref_counter<
   void on_active_advmap(const OSDMapRef &osdmap) final;
 
   epoch_t cluster_osdmap_trim_lower_bound() final {
-    // TODO
-    return 0;
+    return shard_services.get_osdmap_tlb();
   }
 
   void on_backfill_reserved() final {

src/crimson/osd/shard_services.h

@@ -77,6 +77,10 @@ class PerShardState {
   PerfCounters *perf = nullptr;
   PerfCounters *recoverystate_perf = nullptr;
 
+  const epoch_t& get_osdmap_tlb() {
+    return per_shard_superblock.cluster_osdmap_trim_lower_bound;
+  }
+
   // Op Management
   OSDOperationRegistry registry;
   OperationThrottler throttler;
@@ -514,6 +518,7 @@ class ShardServices : public OSDMapService {
   FORWARD_TO_LOCAL_CONST(get_mnow)
   FORWARD_TO_LOCAL(get_hb_stamps)
   FORWARD_TO_LOCAL(update_shard_superblock)
+  FORWARD_TO_LOCAL(get_osdmap_tlb)
 
   FORWARD(pg_created, pg_created, local_state.pg_map)