tasks/cephfs: add test_sessionmap

Tests for the persistence behaviour of SessionMap.

Signed-off-by: John Spray <john.spray@redhat.com>

diff --git a/tasks/cephfs/test_sessionmap.py b/tasks/cephfs/test_sessionmap.py
new file mode 100644 (file)
index 0000000..70ee198
--- /dev/null
+++ b/tasks/cephfs/test_sessionmap.py
@@ -0,0 +1,90 @@
+
+import json
+import logging
+from tasks.cephfs.cephfs_test_case import CephFSTestCase
+
+log = logging.getLogger(__name__)
+
+
+class TestSessionMap(CephFSTestCase):
+    CLIENTS_REQUIRED = 2
+    MDSS_REQUIRED = 2
+
+    def test_version_splitting(self):
+        """
+        That when many sessions are updated, they are correctly
+        split into multiple versions to obey mds_sessionmap_keys_per_op
+        """
+
+        # Start umounted
+        self.mount_a.umount_wait()
+        self.mount_b.umount_wait()
+
+        # Configure MDS to write one OMAP key at once
+        self.set_conf('mds', 'mds_sessionmap_keys_per_op', 1)
+        self.fs.mds_fail_restart()
+        self.fs.wait_for_daemons()
+
+        # I would like two MDSs, so that I can do an export dir later
+        self.fs.mon_manager.raw_cluster_cmd_result('mds', 'set', "max_mds", "2")
+        self.fs.wait_for_daemons()
+
+        active_mds_names = self.fs.get_active_names()
+        rank_0_id = active_mds_names[0]
+        rank_1_id = active_mds_names[1]
+        log.info("Ranks 0 and 1 are {0} and {1}".format(
+            rank_0_id, rank_1_id))
+
+        # Bring the clients back
+        self.mount_a.mount()
+        self.mount_b.mount()
+        self.mount_a.create_files()  # Kick the client into opening sessions
+        self.mount_b.create_files()
+
+        # See that they've got sessions
+        self.assert_session_count(2, mds_id=rank_0_id)
+
+        # See that we persist their sessions
+        self.fs.mds_asok(["flush", "journal"], rank_0_id)
+        table_json = json.loads(self.fs.table_tool(["0", "show", "session"]))
+        log.info("SessionMap: {0}".format(json.dumps(table_json, indent=2)))
+        self.assertEqual(table_json['0']['result'], 0)
+        self.assertEqual(len(table_json['0']['data']['Sessions']), 2)
+
+        # Now, induce a "force_open_sessions" event by exporting a dir
+        self.mount_a.run_shell(["mkdir", "bravo"])
+        self.mount_a.run_shell(["touch", "bravo/file"])
+        self.mount_b.run_shell(["ls", "-l", "bravo/file"])
+
+        def get_omap_wrs():
+            return self.fs.mds_asok(['perf', 'dump', 'objecter'], rank_1_id)['objecter']['omap_wr']
+
+        # Flush so that there are no dirty sessions on rank 1
+        self.fs.mds_asok(["flush", "journal"], rank_1_id)
+
+        # Export so that we get a force_open to rank 1 for the two sessions from rank 0
+        initial_omap_wrs = get_omap_wrs()
+        self.fs.mds_asok(['export', 'dir', '/bravo', '1'], rank_0_id)
+
+        # This is the critical (if rather subtle) check: that in the process of doing an export dir,
+        # we hit force_open_sessions, and as a result we end up writing out the sessionmap.  There
+        # will be two sessions dirtied here, and because we have set keys_per_op to 1, we should see
+        # a single session get written out (the first of the two, triggered by the second getting marked
+        # dirty)
+        # The number of writes is two per session, because the header (sessionmap version) update and
+        # KV write both count.
+        self.assertEqual(get_omap_wrs() - initial_omap_wrs, 2)
+
+        # Now end our sessions and check the backing sessionmap is updated correctly
+        self.mount_a.umount_wait()
+        self.mount_b.umount_wait()
+
+        # In-memory sessionmap check
+        self.assert_session_count(0, mds_id=rank_0_id)
+
+        # On-disk sessionmap check
+        self.fs.mds_asok(["flush", "journal"], rank_0_id)
+        table_json = json.loads(self.fs.table_tool(["0", "show", "session"]))
+        log.info("SessionMap: {0}".format(json.dumps(table_json, indent=2)))
+        self.assertEqual(table_json['0']['result'], 0)
+        self.assertEqual(len(table_json['0']['data']['Sessions']), 0)