doc: update osd snap trimming with a little more detail

Signed-off-by: Greg Farnum <gfarnum@redhat.com>

diff --git a/doc/dev/osd_internals/snaps.rst b/doc/dev/osd_internals/snaps.rst
index 95cc14944b5786a2e1855b0c57342c99934df104..e17378fd2a68955132fbbb28666076ca0f6afad1 100644 (file)
--- a/doc/dev/osd_internals/snaps.rst
+++ b/doc/dev/osd_internals/snaps.rst
@@ -74,6 +74,9 @@ pg is clean and not scrubbing.
   #. We determine the next object for trimming out of PG::snap_mapper.
      For each object, we create a log entry and repop updating the
      object info and the snap set (including adjusting the overlaps).
+     If the object is a clone which no longer belongs to any live snapshots,
+     it is removed here. (See PrimaryLogPG::trim_object() when new_snaps
+     is empty.)
   #. We also locally update our *SnapMapper* instance with the object's
      new snaps.
   #. The log entry containing the modification of the object also
@@ -83,6 +86,7 @@ pg is clean and not scrubbing.
      the new set of purged_snaps along with the rest of the info.
 
 
+
 Recovery
 --------
 Because the trim operations are implemented using repops and log entries,