ceph/qa/tasks/cephfs/test_client_recovery.py

   1
   2 """
   3 Teuthology task for exercising CephFS client recovery
   4 """
   5
   6 import logging
   7 from textwrap import dedent
   8 import time
   9 import distutils.version as version
  10 import re
  11 import os
  12
  13 from teuthology.orchestra import run
  14 from teuthology.orchestra.run import CommandFailedError, ConnectionLostError
  15 from tasks.cephfs.fuse_mount import FuseMount
  16 from tasks.cephfs.cephfs_test_case import CephFSTestCase
  17 from teuthology.packaging import get_package_version
  18
  19 log = logging.getLogger(__name__)
  20
  21
  22 # Arbitrary timeouts for operations involving restarting
  23 # an MDS or waiting for it to come up
  24 MDS_RESTART_GRACE = 60
  25
  26
  27 class TestClientNetworkRecovery(CephFSTestCase):
  28     REQUIRE_KCLIENT_REMOTE = True
  29     REQUIRE_ONE_CLIENT_REMOTE = True
  30     CLIENTS_REQUIRED = 2
  31
  32     LOAD_SETTINGS = ["mds_reconnect_timeout", "ms_max_backoff"]
  33
  34     # Environment references
  35     mds_reconnect_timeout = None
  36     ms_max_backoff = None
  37
  38     def test_network_death(self):
  39         """
  40         Simulate software freeze or temporary network failure.
  41
  42         Check that the client blocks I/O during failure, and completes
  43         I/O after failure.
  44         """
  45
  46         session_timeout = self.fs.get_var("session_timeout")
  47         self.fs.mds_asok(['config', 'set', 'mds_defer_session_stale', 'false'])
  48
  49         # We only need one client
  50         self.mount_b.umount_wait()
  51
  52         # Initially our one client session should be visible
  53         client_id = self.mount_a.get_global_id()
  54         ls_data = self._session_list()
  55         self.assert_session_count(1, ls_data)
  56         self.assertEqual(ls_data[0]['id'], client_id)
  57         self.assert_session_state(client_id, "open")
  58
  59         # ...and capable of doing I/O without blocking
  60         self.mount_a.create_files()
  61
  62         # ...but if we turn off the network
  63         self.fs.set_clients_block(True)
  64
  65         # ...and try and start an I/O
  66         write_blocked = self.mount_a.write_background()
  67
  68         # ...then it should block
  69         self.assertFalse(write_blocked.finished)
  70         self.assert_session_state(client_id, "open")
  71         time.sleep(session_timeout * 1.5)  # Long enough for MDS to consider session stale
  72         self.assertFalse(write_blocked.finished)
  73         self.assert_session_state(client_id, "stale")
  74
  75         # ...until we re-enable I/O
  76         self.fs.set_clients_block(False)
  77
  78         # ...when it should complete promptly
  79         a = time.time()
  80         self.wait_until_true(lambda: write_blocked.finished, self.ms_max_backoff * 2)
  81         write_blocked.wait()  # Already know we're finished, wait() to raise exception on errors
  82         recovery_time = time.time() - a
  83         log.info("recovery time: {0}".format(recovery_time))
  84         self.assert_session_state(client_id, "open")
  85
  86
  87 class TestClientRecovery(CephFSTestCase):
  88     REQUIRE_KCLIENT_REMOTE = True
  89     CLIENTS_REQUIRED = 2
  90
  91     LOAD_SETTINGS = ["mds_reconnect_timeout", "ms_max_backoff"]
  92
  93     # Environment references
  94     mds_reconnect_timeout = None
  95     ms_max_backoff = None
  96
  97     def test_basic(self):
  98         # Check that two clients come up healthy and see each others' files
  99         # =====================================================
 100         self.mount_a.create_files()
 101         self.mount_a.check_files()
 102         self.mount_a.umount_wait()
 103
 104         self.mount_b.check_files()
 105
 106         self.mount_a.mount_wait()
 107
 108         # Check that the admin socket interface is correctly reporting
 109         # two sessions
 110         # =====================================================
 111         ls_data = self._session_list()
 112         self.assert_session_count(2, ls_data)
 113
 114         self.assertSetEqual(
 115             set([l['id'] for l in ls_data]),
 116             {self.mount_a.get_global_id(), self.mount_b.get_global_id()}
 117         )
 118
 119     def test_restart(self):
 120         # Check that after an MDS restart both clients reconnect and continue
 121         # to handle I/O
 122         # =====================================================
 123         self.fs.mds_fail_restart()
 124         self.fs.wait_for_state('up:active', timeout=MDS_RESTART_GRACE)
 125
 126         self.mount_a.create_destroy()
 127         self.mount_b.create_destroy()
 128
 129     def _session_num_caps(self, client_id):
 130         ls_data = self.fs.mds_asok(['session', 'ls'])
 131         return int(self._session_by_id(ls_data).get(client_id, {'num_caps': None})['num_caps'])
 132
 133     def test_reconnect_timeout(self):
 134         # Reconnect timeout
 135         # =================
 136         # Check that if I stop an MDS and a client goes away, the MDS waits
 137         # for the reconnect period
 138         self.fs.mds_stop()
 139         self.fs.mds_fail()
 140
 141         mount_a_client_id = self.mount_a.get_global_id()
 142         self.mount_a.umount_wait(force=True)
 143
 144         self.fs.mds_restart()
 145
 146         self.fs.wait_for_state('up:reconnect', reject='up:active', timeout=MDS_RESTART_GRACE)
 147         # Check that the MDS locally reports its state correctly
 148         status = self.fs.mds_asok(['status'])
 149         self.assertIn("reconnect_status", status)
 150
 151         ls_data = self._session_list()
 152         self.assert_session_count(2, ls_data)
 153
 154         # The session for the dead client should have the 'reconnect' flag set
 155         self.assertTrue(self.get_session(mount_a_client_id)['reconnecting'])
 156
 157         # Wait for the reconnect state to clear, this should take the
 158         # reconnect timeout period.
 159         in_reconnect_for = self.fs.wait_for_state('up:active', timeout=self.mds_reconnect_timeout * 2)
 160         # Check that the period we waited to enter active is within a factor
 161         # of two of the reconnect timeout.
 162         self.assertGreater(in_reconnect_for, self.mds_reconnect_timeout // 2,
 163                            "Should have been in reconnect phase for {0} but only took {1}".format(
 164                                self.mds_reconnect_timeout, in_reconnect_for
 165                            ))
 166
 167         self.assert_session_count(1)
 168
 169         # Check that the client that timed out during reconnect can
 170         # mount again and do I/O
 171         self.mount_a.mount_wait()
 172         self.mount_a.create_destroy()
 173
 174         self.assert_session_count(2)
 175
 176     def test_reconnect_eviction(self):
 177         # Eviction during reconnect
 178         # =========================
 179         mount_a_client_id = self.mount_a.get_global_id()
 180
 181         self.fs.mds_stop()
 182         self.fs.mds_fail()
 183
 184         # The mount goes away while the MDS is offline
 185         self.mount_a.kill()
 186
 187         # wait for it to die
 188         time.sleep(5)
 189
 190         self.fs.mds_restart()
 191
 192         # Enter reconnect phase
 193         self.fs.wait_for_state('up:reconnect', reject='up:active', timeout=MDS_RESTART_GRACE)
 194         self.assert_session_count(2)
 195
 196         # Evict the stuck client
 197         self.fs.mds_asok(['session', 'evict', "%s" % mount_a_client_id])
 198         self.assert_session_count(1)
 199
 200         # Observe that we proceed to active phase without waiting full reconnect timeout
 201         evict_til_active = self.fs.wait_for_state('up:active', timeout=MDS_RESTART_GRACE)
 202         # Once we evict the troublemaker, the reconnect phase should complete
 203         # in well under the reconnect timeout.
 204         self.assertLess(evict_til_active, self.mds_reconnect_timeout * 0.5,
 205                         "reconnect did not complete soon enough after eviction, took {0}".format(
 206                             evict_til_active
 207                         ))
 208
 209         # We killed earlier so must clean up before trying to use again
 210         self.mount_a.kill_cleanup()
 211
 212         # Bring the client back
 213         self.mount_a.mount_wait()
 214         self.mount_a.create_destroy()
 215
 216     def _test_stale_caps(self, write):
 217         session_timeout = self.fs.get_var("session_timeout")
 218
 219         # Capability release from stale session
 220         # =====================================
 221         if write:
 222             cap_holder = self.mount_a.open_background()
 223         else:
 224             self.mount_a.run_shell(["touch", "background_file"])
 225             self.mount_a.umount_wait()
 226             self.mount_a.mount_wait()
 227             cap_holder = self.mount_a.open_background(write=False)
 228
 229         self.assert_session_count(2)
 230         mount_a_gid = self.mount_a.get_global_id()
 231
 232         # Wait for the file to be visible from another client, indicating
 233         # that mount_a has completed its network ops
 234         self.mount_b.wait_for_visible()
 235
 236         # Simulate client death
 237         self.mount_a.kill()
 238
 239         # wait for it to die so it doesn't voluntarily release buffer cap
 240         time.sleep(5)
 241
 242         try:
 243             # Now, after session_timeout seconds, the waiter should
 244             # complete their operation when the MDS marks the holder's
 245             # session stale.
 246             cap_waiter = self.mount_b.write_background()
 247             a = time.time()
 248             cap_waiter.wait()
 249             b = time.time()
 250
 251             # Should have succeeded
 252             self.assertEqual(cap_waiter.exitstatus, 0)
 253
 254             if write:
 255                 self.assert_session_count(1)
 256             else:
 257                 self.assert_session_state(mount_a_gid, "stale")
 258
 259             cap_waited = b - a
 260             log.info("cap_waiter waited {0}s".format(cap_waited))
 261             self.assertTrue(session_timeout / 2.0 <= cap_waited <= session_timeout * 2.0,
 262                             "Capability handover took {0}, expected approx {1}".format(
 263                                 cap_waited, session_timeout
 264                             ))
 265
 266             cap_holder.stdin.close()
 267             try:
 268                 cap_holder.wait()
 269             except (CommandFailedError, ConnectionLostError):
 270                 # We killed it (and possibly its node), so it raises an error
 271                 pass
 272         finally:
 273             # teardown() doesn't quite handle this case cleanly, so help it out
 274             self.mount_a.kill_cleanup()
 275
 276         self.mount_a.mount()
 277         self.mount_a.wait_until_mounted()
 278
 279     def test_stale_read_caps(self):
 280         self._test_stale_caps(False)
 281
 282     def test_stale_write_caps(self):
 283         self._test_stale_caps(True)
 284
 285     def test_evicted_caps(self):
 286         # Eviction while holding a capability
 287         # ===================================
 288
 289         session_timeout = self.fs.get_var("session_timeout")
 290
 291         # Take out a write capability on a file on client A,
 292         # and then immediately kill it.
 293         cap_holder = self.mount_a.open_background()
 294         mount_a_client_id = self.mount_a.get_global_id()
 295
 296         # Wait for the file to be visible from another client, indicating
 297         # that mount_a has completed its network ops
 298         self.mount_b.wait_for_visible()
 299
 300         # Simulate client death
 301         self.mount_a.kill()
 302
 303         # wait for it to die so it doesn't voluntarily release buffer cap
 304         time.sleep(5)
 305
 306         try:
 307             # The waiter should get stuck waiting for the capability
 308             # held on the MDS by the now-dead client A
 309             cap_waiter = self.mount_b.write_background()
 310             time.sleep(5)
 311             self.assertFalse(cap_waiter.finished)
 312
 313             self.fs.mds_asok(['session', 'evict', "%s" % mount_a_client_id])
 314             # Now, because I evicted the old holder of the capability, it should
 315             # immediately get handed over to the waiter
 316             a = time.time()
 317             cap_waiter.wait()
 318             b = time.time()
 319             cap_waited = b - a
 320             log.info("cap_waiter waited {0}s".format(cap_waited))
 321             # This is the check that it happened 'now' rather than waiting
 322             # for the session timeout
 323             self.assertLess(cap_waited, session_timeout / 2.0,
 324                             "Capability handover took {0}, expected less than {1}".format(
 325                                 cap_waited, session_timeout / 2.0
 326                             ))
 327
 328             cap_holder.stdin.close()
 329             try:
 330                 cap_holder.wait()
 331             except (CommandFailedError, ConnectionLostError):
 332                 # We killed it (and possibly its node), so it raises an error
 333                 pass
 334         finally:
 335             self.mount_a.kill_cleanup()
 336
 337         self.mount_a.mount()
 338         self.mount_a.wait_until_mounted()
 339
 340     def test_trim_caps(self):
 341         # Trim capability when reconnecting MDS
 342         # ===================================
 343
 344         count = 500
 345         # Create lots of files
 346         for i in range(count):
 347             self.mount_a.run_shell(["touch", "f{0}".format(i)])
 348
 349         # Populate mount_b's cache
 350         self.mount_b.run_shell(["ls", "-l"])
 351
 352         client_id = self.mount_b.get_global_id()
 353         num_caps = self._session_num_caps(client_id)
 354         self.assertGreaterEqual(num_caps, count)
 355
 356         # Restart MDS. client should trim its cache when reconnecting to the MDS
 357         self.fs.mds_fail_restart()
 358         self.fs.wait_for_state('up:active', timeout=MDS_RESTART_GRACE)
 359
 360         num_caps = self._session_num_caps(client_id)
 361         self.assertLess(num_caps, count,
 362                         "should have less than {0} capabilities, have {1}".format(
 363                             count, num_caps
 364                         ))
 365
 366     def _is_flockable(self):
 367         a_version_str = get_package_version(self.mount_a.client_remote, "fuse")
 368         b_version_str = get_package_version(self.mount_b.client_remote, "fuse")
 369         flock_version_str = "2.9"
 370
 371         version_regex = re.compile(r"[0-9\.]+")
 372         a_result = version_regex.match(a_version_str)
 373         self.assertTrue(a_result)
 374         b_result = version_regex.match(b_version_str)
 375         self.assertTrue(b_result)
 376         a_version = version.StrictVersion(a_result.group())
 377         b_version = version.StrictVersion(b_result.group())
 378         flock_version=version.StrictVersion(flock_version_str)
 379
 380         if (a_version >= flock_version and b_version >= flock_version):
 381             log.info("flock locks are available")
 382             return True
 383         else:
 384             log.info("not testing flock locks, machines have versions {av} and {bv}".format(
 385                 av=a_version_str,bv=b_version_str))
 386             return False
 387
 388     def test_filelock(self):
 389         """
 390         Check that file lock doesn't get lost after an MDS restart
 391         """
 392
 393         flockable = self._is_flockable()
 394         lock_holder = self.mount_a.lock_background(do_flock=flockable)
 395
 396         self.mount_b.wait_for_visible("background_file-2")
 397         self.mount_b.check_filelock(do_flock=flockable)
 398
 399         self.fs.mds_fail_restart()
 400         self.fs.wait_for_state('up:active', timeout=MDS_RESTART_GRACE)
 401
 402         self.mount_b.check_filelock(do_flock=flockable)
 403
 404         # Tear down the background process
 405         lock_holder.stdin.close()
 406         try:
 407             lock_holder.wait()
 408         except (CommandFailedError, ConnectionLostError):
 409             # We killed it, so it raises an error
 410             pass
 411
 412     def test_filelock_eviction(self):
 413         """
 414         Check that file lock held by evicted client is given to
 415         waiting client.
 416         """
 417         if not self._is_flockable():
 418             self.skipTest("flock is not available")
 419
 420         lock_holder = self.mount_a.lock_background()
 421         self.mount_b.wait_for_visible("background_file-2")
 422         self.mount_b.check_filelock()
 423
 424         lock_taker = self.mount_b.lock_and_release()
 425         # Check the taker is waiting (doesn't get it immediately)
 426         time.sleep(2)
 427         self.assertFalse(lock_holder.finished)
 428         self.assertFalse(lock_taker.finished)
 429
 430         try:
 431             mount_a_client_id = self.mount_a.get_global_id()
 432             self.fs.mds_asok(['session', 'evict', "%s" % mount_a_client_id])
 433
 434             # Evicting mount_a should let mount_b's attempt to take the lock
 435             # succeed
 436             self.wait_until_true(lambda: lock_taker.finished, timeout=10)
 437         finally:
 438             # teardown() doesn't quite handle this case cleanly, so help it out
 439             self.mount_a.kill()
 440             self.mount_a.kill_cleanup()
 441
 442         # Bring the client back
 443         self.mount_a.mount_wait()
 444
 445     def test_dir_fsync(self):
 446         self._test_fsync(True);
 447
 448     def test_create_fsync(self):
 449         self._test_fsync(False);
 450
 451     def _test_fsync(self, dirfsync):
 452         """
 453         That calls to fsync guarantee visibility of metadata to another
 454         client immediately after the fsyncing client dies.
 455         """
 456
 457         # Leave this guy out until he's needed
 458         self.mount_b.umount_wait()
 459
 460         # Create dir + child dentry on client A, and fsync the dir
 461         path = os.path.join(self.mount_a.mountpoint, "subdir")
 462         self.mount_a.run_python(
 463             dedent("""
 464                 import os
 465                 import time
 466
 467                 path = "{path}"
 468
 469                 print("Starting creation...")
 470                 start = time.time()
 471
 472                 os.mkdir(path)
 473                 dfd = os.open(path, os.O_DIRECTORY)
 474
 475                 fd = open(os.path.join(path, "childfile"), "w")
 476                 print("Finished creation in {{0}}s".format(time.time() - start))
 477
 478                 print("Starting fsync...")
 479                 start = time.time()
 480                 if {dirfsync}:
 481                     os.fsync(dfd)
 482                 else:
 483                     os.fsync(fd)
 484                 print("Finished fsync in {{0}}s".format(time.time() - start))
 485             """.format(path=path,dirfsync=str(dirfsync)))
 486         )
 487
 488         # Immediately kill the MDS and then client A
 489         self.fs.mds_stop()
 490         self.fs.mds_fail()
 491         self.mount_a.kill()
 492         self.mount_a.kill_cleanup()
 493
 494         # Restart the MDS.  Wait for it to come up, it'll have to time out in clientreplay
 495         self.fs.mds_restart()
 496         log.info("Waiting for reconnect...")
 497         self.fs.wait_for_state("up:reconnect")
 498         log.info("Waiting for active...")
 499         self.fs.wait_for_state("up:active", timeout=MDS_RESTART_GRACE + self.mds_reconnect_timeout)
 500         log.info("Reached active...")
 501
 502         # Is the child dentry visible from mount B?
 503         self.mount_b.mount_wait()
 504         self.mount_b.run_shell(["ls", "subdir/childfile"])
 505
 506     def test_unmount_for_evicted_client(self):
 507         """Test if client hangs on unmount after evicting the client."""
 508         mount_a_client_id = self.mount_a.get_global_id()
 509         self.fs.mds_asok(['session', 'evict', "%s" % mount_a_client_id])
 510
 511         self.mount_a.umount_wait(require_clean=True, timeout=30)
 512
 513     def test_stale_renew(self):
 514         if not isinstance(self.mount_a, FuseMount):
 515             self.skipTest("Require FUSE client to handle signal STOP/CONT")
 516
 517         session_timeout = self.fs.get_var("session_timeout")
 518
 519         self.mount_a.run_shell(["mkdir", "testdir"])
 520         self.mount_a.run_shell(["touch", "testdir/file1"])
 521         # populate readdir cache
 522         self.mount_a.run_shell(["ls", "testdir"])
 523         self.mount_b.run_shell(["ls", "testdir"])
 524
 525         # check if readdir cache is effective
 526         initial_readdirs = self.fs.mds_asok(['perf', 'dump', 'mds_server', 'req_readdir_latency'])
 527         self.mount_b.run_shell(["ls", "testdir"])
 528         current_readdirs = self.fs.mds_asok(['perf', 'dump', 'mds_server', 'req_readdir_latency'])
 529         self.assertEqual(current_readdirs, initial_readdirs);
 530
 531         mount_b_gid = self.mount_b.get_global_id()
 532         mount_b_pid = self.mount_b.get_client_pid()
 533         # stop ceph-fuse process of mount_b
 534         self.mount_b.client_remote.run(args=["sudo", "kill", "-STOP", mount_b_pid])
 535
 536         self.assert_session_state(mount_b_gid, "open")
 537         time.sleep(session_timeout * 1.5)  # Long enough for MDS to consider session stale
 538
 539         self.mount_a.run_shell(["touch", "testdir/file2"])
 540         self.assert_session_state(mount_b_gid, "stale")
 541
 542         # resume ceph-fuse process of mount_b
 543         self.mount_b.client_remote.run(args=["sudo", "kill", "-CONT", mount_b_pid])
 544         # Is the new file visible from mount_b? (caps become invalid after session stale)
 545         self.mount_b.run_shell(["ls", "testdir/file2"])
 546
 547     def test_abort_conn(self):
 548         """
 549         Check that abort_conn() skips closing mds sessions.
 550         """
 551         if not isinstance(self.mount_a, FuseMount):
 552             self.skipTest("Testing libcephfs function")
 553
 554         self.fs.mds_asok(['config', 'set', 'mds_defer_session_stale', 'false'])
 555         session_timeout = self.fs.get_var("session_timeout")
 556
 557         self.mount_a.umount_wait()
 558         self.mount_b.umount_wait()
 559
 560         gid_str = self.mount_a.run_python(dedent("""
 561             import cephfs as libcephfs
 562             cephfs = libcephfs.LibCephFS(conffile='')
 563             cephfs.mount()
 564             client_id = cephfs.get_instance_id()
 565             cephfs.abort_conn()
 566             print(client_id)
 567             """)
 568         )
 569         gid = int(gid_str);
 570
 571         self.assert_session_state(gid, "open")
 572         time.sleep(session_timeout * 1.5)  # Long enough for MDS to consider session stale
 573         self.assert_session_state(gid, "stale")
 574
 575     def test_dont_mark_unresponsive_client_stale(self):
 576         """
 577         Test that an unresponsive client holding caps is not marked stale or
 578         evicted unless another clients wants its caps.
 579         """
 580         if not isinstance(self.mount_a, FuseMount):
 581             self.skipTest("Require FUSE client to handle signal STOP/CONT")
 582
 583         # XXX: To conduct this test we need at least two clients since a
 584         # single client is never evcited by MDS.
 585         SESSION_TIMEOUT = 30
 586         SESSION_AUTOCLOSE = 50
 587         time_at_beg = time.time()
 588         mount_a_gid = self.mount_a.get_global_id()
 589         _ = self.mount_a.client_pid
 590         self.fs.set_var('session_timeout', SESSION_TIMEOUT)
 591         self.fs.set_var('session_autoclose', SESSION_AUTOCLOSE)
 592         self.assert_session_count(2, self.fs.mds_asok(['session', 'ls']))
 593
 594         # test that client holding cap not required by any other client is not
 595         # marked stale when it becomes unresponsive.
 596         self.mount_a.run_shell(['mkdir', 'dir'])
 597         self.mount_a.send_signal('sigstop')
 598         time.sleep(SESSION_TIMEOUT + 2)
 599         self.assert_session_state(mount_a_gid, "open")
 600
 601         # test that other clients have to wait to get the caps from
 602         # unresponsive client until session_autoclose.
 603         self.mount_b.run_shell(['stat', 'dir'])
 604         self.assert_session_count(1, self.fs.mds_asok(['session', 'ls']))
 605         self.assertLess(time.time(), time_at_beg + SESSION_AUTOCLOSE)
 606
 607         self.mount_a.send_signal('sigcont')
 608
 609     def test_config_session_timeout(self):
 610         self.fs.mds_asok(['config', 'set', 'mds_defer_session_stale', 'false'])
 611         session_timeout = self.fs.get_var("session_timeout")
 612         mount_a_gid = self.mount_a.get_global_id()
 613
 614         self.fs.mds_asok(['session', 'config', '%s' % mount_a_gid, 'timeout', '%s' % (session_timeout * 2)])
 615
 616         self.mount_a.kill();
 617
 618         self.assert_session_count(2)
 619
 620         time.sleep(session_timeout * 1.5)
 621         self.assert_session_state(mount_a_gid, "open")
 622
 623         time.sleep(session_timeout)
 624         self.assert_session_count(1)
 625
 626         self.mount_a.kill_cleanup()
 627
 628     def test_reconnect_after_blacklisted(self):
 629         """
 630         Test reconnect after blacklisted.
 631         - writing to a fd that was opened before blacklist should return -EBADF
 632         - reading/writing to a file with lost file locks should return -EIO
 633         - readonly fd should continue to work
 634         """
 635
 636         self.mount_a.umount_wait()
 637
 638         if isinstance(self.mount_a, FuseMount):
 639             self.mount_a.mount(mount_options=['--client_reconnect_stale=1', '--fuse_disable_pagecache=1'])
 640         else:
 641             try:
 642                 self.mount_a.mount(mount_options=['recover_session=clean'])
 643             except CommandFailedError:
 644                 self.mount_a.kill_cleanup()
 645                 self.skipTest("Not implemented in current kernel")
 646
 647         self.mount_a.wait_until_mounted()
 648
 649         path = os.path.join(self.mount_a.mountpoint, 'testfile_reconnect_after_blacklisted')
 650         pyscript = dedent("""
 651             import os
 652             import sys
 653             import fcntl
 654             import errno
 655             import time
 656
 657             fd1 = os.open("{path}.1", os.O_RDWR | os.O_CREAT, 0O666)
 658             fd2 = os.open("{path}.1", os.O_RDONLY)
 659             fd3 = os.open("{path}.2", os.O_RDWR | os.O_CREAT, 0O666)
 660             fd4 = os.open("{path}.2", os.O_RDONLY)
 661
 662             os.write(fd1, b'content')
 663             os.read(fd2, 1);
 664
 665             os.write(fd3, b'content')
 666             os.read(fd4, 1);
 667             fcntl.flock(fd4, fcntl.LOCK_SH | fcntl.LOCK_NB)
 668
 669             print("blacklist")
 670             sys.stdout.flush()
 671
 672             sys.stdin.readline()
 673
 674             # wait for mds to close session
 675             time.sleep(10);
 676
 677             # trigger 'open session' message. kclient relies on 'session reject' message
 678             # to detect if itself is blacklisted
 679             try:
 680                 os.stat("{path}.1")
 681             except:
 682                 pass
 683
 684             # wait for auto reconnect
 685             time.sleep(10);
 686
 687             try:
 688                 os.write(fd1, b'content')
 689             except OSError as e:
 690                 if e.errno != errno.EBADF:
 691                     raise
 692             else:
 693                 raise RuntimeError("write() failed to raise error")
 694
 695             os.read(fd2, 1);
 696
 697             try:
 698                 os.read(fd4, 1)
 699             except OSError as e:
 700                 if e.errno != errno.EIO:
 701                     raise
 702             else:
 703                 raise RuntimeError("read() failed to raise error")
 704             """).format(path=path)
 705         rproc = self.mount_a.client_remote.run(
 706                     args=['sudo', 'python3', '-c', pyscript],
 707                     wait=False, stdin=run.PIPE, stdout=run.PIPE)
 708
 709         rproc.stdout.readline()
 710
 711         mount_a_client_id = self.mount_a.get_global_id()
 712         self.fs.mds_asok(['session', 'evict', "%s" % mount_a_client_id])
 713
 714         rproc.stdin.writelines(['done\n'])
 715         rproc.stdin.flush()
 716
 717         rproc.wait()
 718         self.assertEqual(rproc.exitstatus, 0)