drivers/staging/lustre/lustre/ptlrpc/pinger.c

   1 /*
   2  * GPL HEADER START
   3  *
   4  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 only,
   8  * as published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful, but
  11  * WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * General Public License version 2 for more details (a copy is included
  14  * in the LICENSE file that accompanied this code).
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * version 2 along with this program; If not, see
  18  * http://www.sun.com/software/products/lustre/docs/GPLv2.pdf
  19  *
  20  * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
  21  * CA 95054 USA or visit www.sun.com if you need additional information or
  22  * have any questions.
  23  *
  24  * GPL HEADER END
  25  */
  26 /*
  27  * Copyright (c) 2003, 2010, Oracle and/or its affiliates. All rights reserved.
  28  * Use is subject to license terms.
  29  *
  30  * Copyright (c) 2011, 2012, Intel Corporation.
  31  */
  32 /*
  33  * This file is part of Lustre, http://www.lustre.org/
  34  * Lustre is a trademark of Sun Microsystems, Inc.
  35  *
  36  * lustre/ptlrpc/pinger.c
  37  *
  38  * Portal-RPC reconnection and replay operations, for use in recovery.
  39  */
  40
  41 #define DEBUG_SUBSYSTEM S_RPC
  42
  43 #include "../include/obd_support.h"
  44 #include "../include/obd_class.h"
  45 #include "ptlrpc_internal.h"
  46
  47 static int suppress_pings;
  48 module_param(suppress_pings, int, 0644);
  49 MODULE_PARM_DESC(suppress_pings, "Suppress pings");
  50
  51 struct mutex pinger_mutex;
  52 static LIST_HEAD(pinger_imports);
  53 static struct list_head timeout_list = LIST_HEAD_INIT(timeout_list);
  54
  55 int ptlrpc_pinger_suppress_pings(void)
  56 {
  57         return suppress_pings;
  58 }
  59 EXPORT_SYMBOL(ptlrpc_pinger_suppress_pings);
  60
  61 struct ptlrpc_request *
  62 ptlrpc_prep_ping(struct obd_import *imp)
  63 {
  64         struct ptlrpc_request *req;
  65
  66         req = ptlrpc_request_alloc_pack(imp, &RQF_OBD_PING,
  67                                         LUSTRE_OBD_VERSION, OBD_PING);
  68         if (req) {
  69                 ptlrpc_request_set_replen(req);
  70                 req->rq_no_resend = req->rq_no_delay = 1;
  71         }
  72         return req;
  73 }
  74
  75 int ptlrpc_obd_ping(struct obd_device *obd)
  76 {
  77         int rc;
  78         struct ptlrpc_request *req;
  79
  80         req = ptlrpc_prep_ping(obd->u.cli.cl_import);
  81         if (req == NULL)
  82                 return -ENOMEM;
  83
  84         req->rq_send_state = LUSTRE_IMP_FULL;
  85
  86         rc = ptlrpc_queue_wait(req);
  87
  88         ptlrpc_req_finished(req);
  89
  90         return rc;
  91 }
  92 EXPORT_SYMBOL(ptlrpc_obd_ping);
  93
  94 static int ptlrpc_ping(struct obd_import *imp)
  95 {
  96         struct ptlrpc_request *req;
  97
  98         req = ptlrpc_prep_ping(imp);
  99         if (req == NULL) {
 100                 CERROR("OOM trying to ping %s->%s\n",
 101                        imp->imp_obd->obd_uuid.uuid,
 102                        obd2cli_tgt(imp->imp_obd));
 103                 return -ENOMEM;
 104         }
 105
 106         DEBUG_REQ(D_INFO, req, "pinging %s->%s",
 107                   imp->imp_obd->obd_uuid.uuid, obd2cli_tgt(imp->imp_obd));
 108         ptlrpcd_add_req(req, PDL_POLICY_ROUND, -1);
 109
 110         return 0;
 111 }
 112
 113 static void ptlrpc_update_next_ping(struct obd_import *imp, int soon)
 114 {
 115         int time = soon ? PING_INTERVAL_SHORT : PING_INTERVAL;
 116         if (imp->imp_state == LUSTRE_IMP_DISCON) {
 117                 int dtime = max_t(int, CONNECTION_SWITCH_MIN,
 118                                   AT_OFF ? 0 :
 119                                   at_get(&imp->imp_at.iat_net_latency));
 120                 time = min(time, dtime);
 121         }
 122         imp->imp_next_ping = cfs_time_shift(time);
 123 }
 124
 125 void ptlrpc_ping_import_soon(struct obd_import *imp)
 126 {
 127         imp->imp_next_ping = cfs_time_current();
 128 }
 129
 130 static inline int imp_is_deactive(struct obd_import *imp)
 131 {
 132         return (imp->imp_deactive ||
 133                 OBD_FAIL_CHECK(OBD_FAIL_PTLRPC_IMP_DEACTIVE));
 134 }
 135
 136 static inline int ptlrpc_next_reconnect(struct obd_import *imp)
 137 {
 138         if (imp->imp_server_timeout)
 139                 return cfs_time_shift(obd_timeout / 2);
 140         else
 141                 return cfs_time_shift(obd_timeout);
 142 }
 143
 144 static long pinger_check_timeout(unsigned long time)
 145 {
 146         struct timeout_item *item;
 147         unsigned long timeout = PING_INTERVAL;
 148
 149         /* The timeout list is a increase order sorted list */
 150         mutex_lock(&pinger_mutex);
 151         list_for_each_entry(item, &timeout_list, ti_chain) {
 152                 int ti_timeout = item->ti_timeout;
 153                 if (timeout > ti_timeout)
 154                         timeout = ti_timeout;
 155                 break;
 156         }
 157         mutex_unlock(&pinger_mutex);
 158
 159         return cfs_time_sub(cfs_time_add(time, cfs_time_seconds(timeout)),
 160                                          cfs_time_current());
 161 }
 162
 163 static bool ir_up;
 164
 165 void ptlrpc_pinger_ir_up(void)
 166 {
 167         CDEBUG(D_HA, "IR up\n");
 168         ir_up = true;
 169 }
 170 EXPORT_SYMBOL(ptlrpc_pinger_ir_up);
 171
 172 void ptlrpc_pinger_ir_down(void)
 173 {
 174         CDEBUG(D_HA, "IR down\n");
 175         ir_up = false;
 176 }
 177 EXPORT_SYMBOL(ptlrpc_pinger_ir_down);
 178
 179 static void ptlrpc_pinger_process_import(struct obd_import *imp,
 180                                          unsigned long this_ping)
 181 {
 182         int level;
 183         int force;
 184         int force_next;
 185         int suppress;
 186
 187         spin_lock(&imp->imp_lock);
 188
 189         level = imp->imp_state;
 190         force = imp->imp_force_verify;
 191         force_next = imp->imp_force_next_verify;
 192         /*
 193          * This will be used below only if the import is "FULL".
 194          */
 195         suppress = ir_up && OCD_HAS_FLAG(&imp->imp_connect_data, PINGLESS);
 196
 197         imp->imp_force_verify = 0;
 198
 199         if (cfs_time_aftereq(imp->imp_next_ping - 5 * CFS_TICK, this_ping) &&
 200             !force) {
 201                 spin_unlock(&imp->imp_lock);
 202                 return;
 203         }
 204
 205         imp->imp_force_next_verify = 0;
 206
 207         spin_unlock(&imp->imp_lock);
 208
 209         CDEBUG(level == LUSTRE_IMP_FULL ? D_INFO : D_HA, "%s->%s: level %s/%u force %u force_next %u deactive %u pingable %u suppress %u\n",
 210                imp->imp_obd->obd_uuid.uuid, obd2cli_tgt(imp->imp_obd),
 211                ptlrpc_import_state_name(level), level, force, force_next,
 212                imp->imp_deactive, imp->imp_pingable, suppress);
 213
 214         if (level == LUSTRE_IMP_DISCON && !imp_is_deactive(imp)) {
 215                 /* wait for a while before trying recovery again */
 216                 imp->imp_next_ping = ptlrpc_next_reconnect(imp);
 217                 if (!imp->imp_no_pinger_recover)
 218                         ptlrpc_initiate_recovery(imp);
 219         } else if (level != LUSTRE_IMP_FULL ||
 220                    imp->imp_obd->obd_no_recov ||
 221                    imp_is_deactive(imp)) {
 222                 CDEBUG(D_HA, "%s->%s: not pinging (in recovery or recovery disabled: %s)\n",
 223                        imp->imp_obd->obd_uuid.uuid, obd2cli_tgt(imp->imp_obd),
 224                        ptlrpc_import_state_name(level));
 225                 if (force) {
 226                         spin_lock(&imp->imp_lock);
 227                         imp->imp_force_verify = 1;
 228                         spin_unlock(&imp->imp_lock);
 229                 }
 230         } else if ((imp->imp_pingable && !suppress) || force_next || force) {
 231                 ptlrpc_ping(imp);
 232         }
 233 }
 234
 235 static int ptlrpc_pinger_main(void *arg)
 236 {
 237         struct ptlrpc_thread *thread = (struct ptlrpc_thread *)arg;
 238
 239         /* Record that the thread is running */
 240         thread_set_flags(thread, SVC_RUNNING);
 241         wake_up(&thread->t_ctl_waitq);
 242
 243         /* And now, loop forever, pinging as needed. */
 244         while (1) {
 245                 unsigned long this_ping = cfs_time_current();
 246                 struct l_wait_info lwi;
 247                 long time_to_next_wake;
 248                 struct timeout_item *item;
 249                 struct list_head *iter;
 250
 251                 mutex_lock(&pinger_mutex);
 252                 list_for_each_entry(item, &timeout_list, ti_chain) {
 253                         item->ti_cb(item, item->ti_cb_data);
 254                 }
 255                 list_for_each(iter, &pinger_imports) {
 256                         struct obd_import *imp =
 257                                 list_entry(iter, struct obd_import,
 258                                                imp_pinger_chain);
 259
 260                         ptlrpc_pinger_process_import(imp, this_ping);
 261                         /* obd_timeout might have changed */
 262                         if (imp->imp_pingable && imp->imp_next_ping &&
 263                             cfs_time_after(imp->imp_next_ping,
 264                                            cfs_time_add(this_ping,
 265                                                         cfs_time_seconds(PING_INTERVAL))))
 266                                 ptlrpc_update_next_ping(imp, 0);
 267                 }
 268                 mutex_unlock(&pinger_mutex);
 269                 /* update memory usage info */
 270                 obd_update_maxusage();
 271
 272                 /* Wait until the next ping time, or until we're stopped. */
 273                 time_to_next_wake = pinger_check_timeout(this_ping);
 274                 /* The ping sent by ptlrpc_send_rpc may get sent out
 275                    say .01 second after this.
 276                    ptlrpc_pinger_sending_on_import will then set the
 277                    next ping time to next_ping + .01 sec, which means
 278                    we will SKIP the next ping at next_ping, and the
 279                    ping will get sent 2 timeouts from now!  Beware. */
 280                 CDEBUG(D_INFO, "next wakeup in "CFS_DURATION_T" ("
 281                        CFS_TIME_T")\n", time_to_next_wake,
 282                        cfs_time_add(this_ping,
 283                                     cfs_time_seconds(PING_INTERVAL)));
 284                 if (time_to_next_wake > 0) {
 285                         lwi = LWI_TIMEOUT(max_t(long, time_to_next_wake,
 286                                                 cfs_time_seconds(1)),
 287                                           NULL, NULL);
 288                         l_wait_event(thread->t_ctl_waitq,
 289                                      thread_is_stopping(thread) ||
 290                                      thread_is_event(thread),
 291                                      &lwi);
 292                         if (thread_test_and_clear_flags(thread, SVC_STOPPING))
 293                                 break;
 294                         /* woken after adding import to reset timer */
 295                         thread_test_and_clear_flags(thread, SVC_EVENT);
 296                 }
 297         }
 298
 299         thread_set_flags(thread, SVC_STOPPED);
 300         wake_up(&thread->t_ctl_waitq);
 301
 302         CDEBUG(D_NET, "pinger thread exiting, process %d\n", current_pid());
 303         return 0;
 304 }
 305
 306 static struct ptlrpc_thread pinger_thread;
 307
 308 int ptlrpc_start_pinger(void)
 309 {
 310         struct l_wait_info lwi = { 0 };
 311         int rc;
 312
 313         if (!thread_is_init(&pinger_thread) &&
 314             !thread_is_stopped(&pinger_thread))
 315                 return -EALREADY;
 316
 317         init_waitqueue_head(&pinger_thread.t_ctl_waitq);
 318
 319         strcpy(pinger_thread.t_name, "ll_ping");
 320
 321         rc = PTR_ERR(kthread_run(ptlrpc_pinger_main, &pinger_thread,
 322                                  "%s", pinger_thread.t_name));
 323         if (IS_ERR_VALUE(rc)) {
 324                 CERROR("cannot start thread: %d\n", rc);
 325                 return rc;
 326         }
 327         l_wait_event(pinger_thread.t_ctl_waitq,
 328                      thread_is_running(&pinger_thread), &lwi);
 329
 330         if (suppress_pings)
 331                 CWARN("Pings will be suppressed at the request of the administrator.  The configuration shall meet the additional requirements described in the manual.  (Search for the \"suppress_pings\" kernel module parameter.)\n");
 332
 333         return 0;
 334 }
 335
 336 int ptlrpc_pinger_remove_timeouts(void);
 337
 338 int ptlrpc_stop_pinger(void)
 339 {
 340         struct l_wait_info lwi = { 0 };
 341         int rc = 0;
 342
 343         if (thread_is_init(&pinger_thread) ||
 344             thread_is_stopped(&pinger_thread))
 345                 return -EALREADY;
 346
 347         ptlrpc_pinger_remove_timeouts();
 348         thread_set_flags(&pinger_thread, SVC_STOPPING);
 349         wake_up(&pinger_thread.t_ctl_waitq);
 350
 351         l_wait_event(pinger_thread.t_ctl_waitq,
 352                      thread_is_stopped(&pinger_thread), &lwi);
 353
 354         return rc;
 355 }
 356
 357 void ptlrpc_pinger_sending_on_import(struct obd_import *imp)
 358 {
 359         ptlrpc_update_next_ping(imp, 0);
 360 }
 361 EXPORT_SYMBOL(ptlrpc_pinger_sending_on_import);
 362
 363 void ptlrpc_pinger_commit_expected(struct obd_import *imp)
 364 {
 365         ptlrpc_update_next_ping(imp, 1);
 366         assert_spin_locked(&imp->imp_lock);
 367         /*
 368          * Avoid reading stale imp_connect_data.  When not sure if pings are
 369          * expected or not on next connection, we assume they are not and force
 370          * one anyway to guarantee the chance of updating
 371          * imp_peer_committed_transno.
 372          */
 373         if (imp->imp_state != LUSTRE_IMP_FULL ||
 374             OCD_HAS_FLAG(&imp->imp_connect_data, PINGLESS))
 375                 imp->imp_force_next_verify = 1;
 376 }
 377
 378 int ptlrpc_pinger_add_import(struct obd_import *imp)
 379 {
 380         if (!list_empty(&imp->imp_pinger_chain))
 381                 return -EALREADY;
 382
 383         mutex_lock(&pinger_mutex);
 384         CDEBUG(D_HA, "adding pingable import %s->%s\n",
 385                imp->imp_obd->obd_uuid.uuid, obd2cli_tgt(imp->imp_obd));
 386         /* if we add to pinger we want recovery on this import */
 387         imp->imp_obd->obd_no_recov = 0;
 388         ptlrpc_update_next_ping(imp, 0);
 389         /* XXX sort, blah blah */
 390         list_add_tail(&imp->imp_pinger_chain, &pinger_imports);
 391         class_import_get(imp);
 392
 393         ptlrpc_pinger_wake_up();
 394         mutex_unlock(&pinger_mutex);
 395
 396         return 0;
 397 }
 398 EXPORT_SYMBOL(ptlrpc_pinger_add_import);
 399
 400 int ptlrpc_pinger_del_import(struct obd_import *imp)
 401 {
 402         if (list_empty(&imp->imp_pinger_chain))
 403                 return -ENOENT;
 404
 405         mutex_lock(&pinger_mutex);
 406         list_del_init(&imp->imp_pinger_chain);
 407         CDEBUG(D_HA, "removing pingable import %s->%s\n",
 408                imp->imp_obd->obd_uuid.uuid, obd2cli_tgt(imp->imp_obd));
 409         /* if we remove from pinger we don't want recovery on this import */
 410         imp->imp_obd->obd_no_recov = 1;
 411         class_import_put(imp);
 412         mutex_unlock(&pinger_mutex);
 413         return 0;
 414 }
 415 EXPORT_SYMBOL(ptlrpc_pinger_del_import);
 416
 417 /**
 418  * Register a timeout callback to the pinger list, and the callback will
 419  * be called when timeout happens.
 420  */
 421 static struct timeout_item *ptlrpc_new_timeout(int time,
 422         enum timeout_event event, timeout_cb_t cb, void *data)
 423 {
 424         struct timeout_item *ti;
 425
 426         ti = kzalloc(sizeof(*ti), GFP_NOFS);
 427         if (!ti)
 428                 return NULL;
 429
 430         INIT_LIST_HEAD(&ti->ti_obd_list);
 431         INIT_LIST_HEAD(&ti->ti_chain);
 432         ti->ti_timeout = time;
 433         ti->ti_event = event;
 434         ti->ti_cb = cb;
 435         ti->ti_cb_data = data;
 436
 437         return ti;
 438 }
 439
 440 /**
 441  * Register timeout event on the pinger thread.
 442  * Note: the timeout list is an sorted list with increased timeout value.
 443  */
 444 static struct timeout_item*
 445 ptlrpc_pinger_register_timeout(int time, enum timeout_event event,
 446                                timeout_cb_t cb, void *data)
 447 {
 448         struct timeout_item *item, *tmp;
 449
 450         LASSERT(mutex_is_locked(&pinger_mutex));
 451
 452         list_for_each_entry(item, &timeout_list, ti_chain)
 453                 if (item->ti_event == event)
 454                         goto out;
 455
 456         item = ptlrpc_new_timeout(time, event, cb, data);
 457         if (item) {
 458                 list_for_each_entry_reverse(tmp, &timeout_list, ti_chain) {
 459                         if (tmp->ti_timeout < time) {
 460                                 list_add(&item->ti_chain, &tmp->ti_chain);
 461                                 goto out;
 462                         }
 463                 }
 464                 list_add(&item->ti_chain, &timeout_list);
 465         }
 466 out:
 467         return item;
 468 }
 469
 470 /* Add a client_obd to the timeout event list, when timeout(@time)
 471  * happens, the callback(@cb) will be called.
 472  */
 473 int ptlrpc_add_timeout_client(int time, enum timeout_event event,
 474                               timeout_cb_t cb, void *data,
 475                               struct list_head *obd_list)
 476 {
 477         struct timeout_item *ti;
 478
 479         mutex_lock(&pinger_mutex);
 480         ti = ptlrpc_pinger_register_timeout(time, event, cb, data);
 481         if (!ti) {
 482                 mutex_unlock(&pinger_mutex);
 483                 return -EINVAL;
 484         }
 485         list_add(obd_list, &ti->ti_obd_list);
 486         mutex_unlock(&pinger_mutex);
 487         return 0;
 488 }
 489 EXPORT_SYMBOL(ptlrpc_add_timeout_client);
 490
 491 int ptlrpc_del_timeout_client(struct list_head *obd_list,
 492                               enum timeout_event event)
 493 {
 494         struct timeout_item *ti = NULL, *item;
 495
 496         if (list_empty(obd_list))
 497                 return 0;
 498         mutex_lock(&pinger_mutex);
 499         list_del_init(obd_list);
 500         /**
 501          * If there are no obd attached to the timeout event
 502          * list, remove this timeout event from the pinger
 503          */
 504         list_for_each_entry(item, &timeout_list, ti_chain) {
 505                 if (item->ti_event == event) {
 506                         ti = item;
 507                         break;
 508                 }
 509         }
 510         LASSERTF(ti != NULL, "ti is NULL !\n");
 511         if (list_empty(&ti->ti_obd_list)) {
 512                 list_del(&ti->ti_chain);
 513                 kfree(ti);
 514         }
 515         mutex_unlock(&pinger_mutex);
 516         return 0;
 517 }
 518 EXPORT_SYMBOL(ptlrpc_del_timeout_client);
 519
 520 int ptlrpc_pinger_remove_timeouts(void)
 521 {
 522         struct timeout_item *item, *tmp;
 523
 524         mutex_lock(&pinger_mutex);
 525         list_for_each_entry_safe(item, tmp, &timeout_list, ti_chain) {
 526                 LASSERT(list_empty(&item->ti_obd_list));
 527                 list_del(&item->ti_chain);
 528                 kfree(item);
 529         }
 530         mutex_unlock(&pinger_mutex);
 531         return 0;
 532 }
 533
 534 void ptlrpc_pinger_wake_up(void)
 535 {
 536         thread_add_flags(&pinger_thread, SVC_EVENT);
 537         wake_up(&pinger_thread.t_ctl_waitq);
 538 }
 539
 540 /* Ping evictor thread */
 541 #define PET_READY     1
 542 #define PET_TERMINATE 2
 543
 544 static int pet_refcount;
 545 static int pet_state;
 546 static wait_queue_head_t pet_waitq;
 547 static LIST_HEAD(pet_list);
 548 static DEFINE_SPINLOCK(pet_lock);
 549
 550 int ping_evictor_wake(struct obd_export *exp)
 551 {
 552         struct obd_device *obd;
 553
 554         spin_lock(&pet_lock);
 555         if (pet_state != PET_READY) {
 556                 /* eventually the new obd will call here again. */
 557                 spin_unlock(&pet_lock);
 558                 return 1;
 559         }
 560
 561         obd = class_exp2obd(exp);
 562         if (list_empty(&obd->obd_evict_list)) {
 563                 class_incref(obd, "evictor", obd);
 564                 list_add(&obd->obd_evict_list, &pet_list);
 565         }
 566         spin_unlock(&pet_lock);
 567
 568         wake_up(&pet_waitq);
 569         return 0;
 570 }
 571
 572 static int ping_evictor_main(void *arg)
 573 {
 574         struct obd_device *obd;
 575         struct obd_export *exp;
 576         struct l_wait_info lwi = { 0 };
 577         time_t expire_time;
 578
 579         unshare_fs_struct();
 580
 581         CDEBUG(D_HA, "Starting Ping Evictor\n");
 582         pet_state = PET_READY;
 583         while (1) {
 584                 l_wait_event(pet_waitq, (!list_empty(&pet_list)) ||
 585                              (pet_state == PET_TERMINATE), &lwi);
 586
 587                 /* loop until all obd's will be removed */
 588                 if ((pet_state == PET_TERMINATE) && list_empty(&pet_list))
 589                         break;
 590
 591                 /* we only get here if pet_exp != NULL, and the end of this
 592                  * loop is the only place which sets it NULL again, so lock
 593                  * is not strictly necessary. */
 594                 spin_lock(&pet_lock);
 595                 obd = list_entry(pet_list.next, struct obd_device,
 596                                      obd_evict_list);
 597                 spin_unlock(&pet_lock);
 598
 599                 expire_time = get_seconds() - PING_EVICT_TIMEOUT;
 600
 601                 CDEBUG(D_HA, "evicting all exports of obd %s older than %ld\n",
 602                        obd->obd_name, expire_time);
 603
 604                 /* Exports can't be deleted out of the list while we hold
 605                  * the obd lock (class_unlink_export), which means we can't
 606                  * lose the last ref on the export.  If they've already been
 607                  * removed from the list, we won't find them here. */
 608                 spin_lock(&obd->obd_dev_lock);
 609                 while (!list_empty(&obd->obd_exports_timed)) {
 610                         exp = list_entry(obd->obd_exports_timed.next,
 611                                              struct obd_export,
 612                                              exp_obd_chain_timed);
 613                         if (expire_time > exp->exp_last_request_time) {
 614                                 class_export_get(exp);
 615                                 spin_unlock(&obd->obd_dev_lock);
 616                                 LCONSOLE_WARN("%s: haven't heard from client %s (at %s) in %ld seconds. I think it's dead, and I am evicting it. exp %p, cur %ld expire %ld last %ld\n",
 617                                               obd->obd_name,
 618                                               obd_uuid2str(&exp->exp_client_uuid),
 619                                               obd_export_nid2str(exp),
 620                                               (long)(get_seconds() -
 621                                                      exp->exp_last_request_time),
 622                                               exp, (long)get_seconds(),
 623                                               (long)expire_time,
 624                                               (long)exp->exp_last_request_time);
 625                                 CDEBUG(D_HA, "Last request was at %ld\n",
 626                                        exp->exp_last_request_time);
 627                                 class_fail_export(exp);
 628                                 class_export_put(exp);
 629                                 spin_lock(&obd->obd_dev_lock);
 630                         } else {
 631                                 /* List is sorted, so everyone below is ok */
 632                                 break;
 633                         }
 634                 }
 635                 spin_unlock(&obd->obd_dev_lock);
 636
 637                 spin_lock(&pet_lock);
 638                 list_del_init(&obd->obd_evict_list);
 639                 spin_unlock(&pet_lock);
 640
 641                 class_decref(obd, "evictor", obd);
 642         }
 643         CDEBUG(D_HA, "Exiting Ping Evictor\n");
 644
 645         return 0;
 646 }
 647
 648 void ping_evictor_start(void)
 649 {
 650         struct task_struct *task;
 651
 652         if (++pet_refcount > 1)
 653                 return;
 654
 655         init_waitqueue_head(&pet_waitq);
 656
 657         task = kthread_run(ping_evictor_main, NULL, "ll_evictor");
 658         if (IS_ERR(task)) {
 659                 pet_refcount--;
 660                 CERROR("Cannot start ping evictor thread: %ld\n",
 661                         PTR_ERR(task));
 662         }
 663 }
 664 EXPORT_SYMBOL(ping_evictor_start);
 665
 666 void ping_evictor_stop(void)
 667 {
 668         if (--pet_refcount > 0)
 669                 return;
 670
 671         pet_state = PET_TERMINATE;
 672         wake_up(&pet_waitq);
 673 }
 674 EXPORT_SYMBOL(ping_evictor_stop);