From: Jon Bailey <jonathan.bailey1@ibm.com>
Date: Tue, 27 Jan 2026 16:59:28 +0000 (+0000)
Subject: osd: Reduce the amount of status invalidations when rolling shards forwards during... 
X-Git-Url: http://git-server-git.apps.pok.os.sepia.ceph.com/?a=commitdiff_plain;h=ccbeb980515ee148ddb9fd06f6eb2a13c70afb98;p=ceph.git

osd: Reduce the amount of status invalidations when rolling shards forwards during peering

Currently stats invalidations happen during peering when rolling forward shards.
We can reduce this so we only invalidate the stats when we don't have any other shards at the version we want to roll the stats forwards to.
In the cases where we have a shard with the stats at the correct version, we use those stats instead of invalidating.
If we do not have any shards with the correct version of stats, we do the invalidate as before.
We also add a check to ensure that we don't use stats from a non-primary shard if the head of the log is a partial write, to prevent incorrect stats in fast ec.

Signed-off-by: Jon Bailey <jonathan.bailey1@ibm.com>
---

diff --git a/src/osd/PeeringState.cc b/src/osd/PeeringState.cc
index bcd56504943e..d723710003fc 100644
--- a/src/osd/PeeringState.cc
+++ b/src/osd/PeeringState.cc
@@ -6,6 +6,7 @@
 #include "osd_perf_counters.h"
 #include "common/ceph_releases.h"
 #include "common/debug.h"
+#include "common/JSONFormatter.h"
 #include "common/ostream_temp.h"
 #include "crush/crush.h" // for CRUSH_ITEM_NONE
 #include "crush/CrushWrapper.h"
@@ -3394,6 +3395,7 @@ void PeeringState::proc_master_log(
 	       &olog);
   }
 
+  const pg_log_entry_t* head_log_entry = nullptr;
   bool invalidate_stats = false;
 
   // For partial writes we may be able to keep some of the divergent entries
@@ -3403,7 +3405,10 @@ void PeeringState::proc_master_log(
     while (p != pg_log.get_log().log.begin()) {
       --p;
       if (p->version <= olog.head) {
-	break;
+        if (p->version == olog.head) {
+          head_log_entry = &(*p);
+        }
+        break;
       }
     }
     if (p == pg_log.get_log().log.end()) {
@@ -3501,22 +3506,74 @@ void PeeringState::proc_master_log(
       }
       rollbacker.get()->partial_write(&info, previous_version, *p);
       olog.head = p->version;
+      head_log_entry = &(*p);
 
       // Process the next entry
       ++p;
     }
   }
+
+  // Find the version we want to roll forwards to
+  // Iterate over all shards and see if any have a last_update equal to where we want to roll to
+  // Copy the stats for this shard into oinfo
+  // Set invalidate_stats to false again if we do copy these stats
+  // We will only copy stats if they are copied from a primary, or if they are
+  // copied from a non-primary where the last write was a non-partial write
+  // as the stats of non-primaries are stale after partial writes on objects with clones
+  if (invalidate_stats && pool.info.allows_ecoptimizations()) {
+    for (const auto& [shard, my_info] : peer_info) {
+      if (invalidate_stats && my_info.stats.version == olog.head &&
+          (!pool.info.is_nonprimary_shard(shard.shard) ||
+           (head_log_entry &&
+            head_log_entry->is_written_shard(shard.shard)))) {
+        oinfo.stats = my_info.stats;
+        invalidate_stats = false;
+        psdout(10) << "keeping stats for " << shard
+                   << " (wanted last update: " << olog.head
+                   << ", stats version: " << my_info.stats.version
+                   << ", shard last update: " << my_info.last_update << ")."
+                   << " Stats: ";
+
+        JSONFormatter f;
+        oinfo.stats.dump(&f);
+        f.flush(*_dout);
+
+        *_dout << dendl;
+      } else {
+        psdout(20) << "not using stats for " << shard
+                   << " (wanted last update: " << olog.head
+                   << ", stats version: " << my_info.stats.version
+                   << ", shard last update: " << my_info.last_update << ")."
+                   << " Stats: ";
+
+        JSONFormatter f;
+        my_info.stats.dump(&f);
+        f.flush(*_dout);
+
+        *_dout << dendl;
+      }
+    }
+  }
+
   // merge log into our own log to build master log.  no need to
   // make any adjustments to their missing map; we are taking their
   // log to be authoritative (i.e., their entries are by definitely
   // non-divergent).
   merge_log(t, oinfo, std::move(olog), from);
   if (info.last_backfill.is_max() &&
-      pool.info.is_nonprimary_shard(from.shard)) {
+      (pool.info.allows_ecoptimizations() &&
+       pool.info.is_nonprimary_shard(from.shard) &&
+      (!head_log_entry ||
+       !head_log_entry->is_written_shard(from.shard)))){
     invalidate_stats = true;
   }
+
   info.stats.stats_invalid |= invalidate_stats;
   increment_stats_invalidations_counter(invalidate_stats);
+  if (invalidate_stats)
+  {
+    psdout(10) << "invalidating stats for " << pg_whoami << dendl;
+  }
   peer_info[from] = oinfo;
   psdout(10) << " peer osd." << from << " now " << oinfo
 	     << " " << omissing << dendl;