mds: skip export of empty directories

Note: empty as in no cached sub-entries.

Signed-off-by: Patrick Donnelly <pdonnell@redhat.com>
(cherry picked from commit 570e6cfbcfc98f877a0e21cf536dfc826a4f9d15)

diff --git a/src/mds/MDBalancer.cc b/src/mds/MDBalancer.cc
index 89f4040fa2c83aaeeb876c10bdf607b47e5d1cbf..c3bac659ecf1d547f3a1f11082c346bc32d2eb4e 100644 (file)
--- a/src/mds/MDBalancer.cc
+++ b/src/mds/MDBalancer.cc
@@ -145,7 +145,12 @@ void MDBalancer::handle_export_pins(void)
          dir->state_set(CDir::STATE_AUXSUBTREE);
        }
       } else {
-       mds->mdcache->migrator->export_dir(dir, export_pin);
+        /* Only export a directory if it's non-empty. An empty directory will
+         * be sent back by the importer.
+         */
+        if (dir->get_num_head_items() > 0) {
+         mds->mdcache->migrator->export_dir(dir, export_pin);
+        }
        remove = false;
       }
     }