osd: Invalidate stats during peering if we are rolling a shard forwards.

This change will mean we always recalculate stats upon rolling stats forwards. This prevent the situation where we end up with incorrect statistics due to where we always take the stats of the oldest shard during peering; causing outdated pg stats being applied for cases where the oldest shards are shards that don't see partial writes where num_bytes has changed on other places after that point on that shard.

Signed-off-by: Jon Bailey <[email protected]>

Author: JonBailey1993

src/osd/PeeringState.cc

@@ -3333,6 +3333,9 @@ void PeeringState::proc_master_log(
     apply_pwlc(info.partial_writes_last_complete[from.shard], from, oinfo,
 	       &olog);
   }
+
+  bool invalidate_stats = false;
+
   // For partial writes we may be able to keep some of the divergent entries
   if (olog.head < pg_log.get_head()) {
     // Iterate backwards to divergence
@@ -3410,6 +3413,7 @@ void PeeringState::proc_master_log(
       // This entry can be kept, only shards that didn't participate in
       // the partial write missed the update
       psdout(20) << "keeping entry " << p->version << dendl;
+      invalidate_stats = true;
       eversion_t previous_version;
 	if (p == pg_log.get_log().log.begin()) {
 	  previous_version = pg_log.get_tail();
@@ -3427,6 +3431,7 @@ void PeeringState::proc_master_log(
   // log to be authoritative (i.e., their entries are by definitely
   // non-divergent).
   merge_log(t, oinfo, std::move(olog), from);
+  info.stats.stats_invalid |= invalidate_stats;
   peer_info[from] = oinfo;
   psdout(10) << " peer osd." << from << " now " << oinfo
 	     << " " << omissing << dendl;