crimson/osd/osd_operations/pg_advance_map: 'from' epoch may vary between PGS explanation

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

diff --git a/src/crimson/osd/osd_operations/pg_advance_map.cc b/src/crimson/osd/osd_operations/pg_advance_map.cc
index cd2ef615b417e53f61fd0747fa8c01900032c9b3..7a9b0ffb45fcd352b54cef86ca7bbd9007cd905d 100644 (file)
--- a/src/crimson/osd/osd_operations/pg_advance_map.cc
+++ b/src/crimson/osd/osd_operations/pg_advance_map.cc
@@ -65,6 +65,15 @@ seastar::future<> PGAdvanceMap::start()
   return enter_stage<>(
     pg->peering_request_pg_pipeline.process
   ).then([this] {
+    /*
+     * PGAdvanceMap is scheduled at pg creation and when
+     * broadcasting new osdmaps to pgs. We are not able to serialize
+     * between the two different PGAdvanceMap callers since a new pg
+     * will get advanced to the latest osdmap at it's creation.
+     * As a result, we may need to adjust the PGAdvance operation
+     * 'from' epoch.
+     * See: https://tracker.ceph.com/issues/61744
+     */
     from = pg->get_osdmap_epoch();
     auto fut = seastar::now();
     if (do_init) {