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.gnu.org/licenses/gpl-2.0.html
  19  *
  20  * GPL HEADER END
  21  */
  22 /*
  23  * Copyright (c) 2003, 2010, Oracle and/or its affiliates. All rights reserved.
  24  * Use is subject to license terms.
  25  *
  26  * Copyright (c) 2011, 2015, Intel Corporation.
  27  */
  28 /*
  29  * This file is part of Lustre, http://www.lustre.org/
  30  * Lustre is a trademark of Sun Microsystems, Inc.
  31  *
  32  * lustre/ptlrpc/pinger.c
  33  *
  34  * Portal-RPC reconnection and replay operations, for use in recovery.
  35  */
  36
  37 #define DEBUG_SUBSYSTEM S_RPC
  38
  39 #include <linux/kthread.h>
  40 #include <obd_support.h>
  41 #include <obd_class.h>
  42 #include "ptlrpc_internal.h"
  43
  44 static int suppress_pings;
  45 module_param(suppress_pings, int, 0644);
  46 MODULE_PARM_DESC(suppress_pings, "Suppress pings");
  47
  48 struct mutex pinger_mutex;
  49 static struct list_head pinger_imports =
  50                 LIST_HEAD_INIT(pinger_imports);
  51 static struct list_head timeout_list =
  52                 LIST_HEAD_INIT(timeout_list);
  53
  54 int ptlrpc_pinger_suppress_pings()
  55 {
  56         return suppress_pings;
  57 }
  58 EXPORT_SYMBOL(ptlrpc_pinger_suppress_pings);
  59
  60 struct ptlrpc_request *
  61 ptlrpc_prep_ping(struct obd_import *imp)
  62 {
  63         struct ptlrpc_request *req;
  64
  65         req = ptlrpc_request_alloc_pack(imp, &RQF_OBD_PING,
  66                                         LUSTRE_OBD_VERSION, OBD_PING);
  67         if (req) {
  68                 ptlrpc_request_set_replen(req);
  69                 req->rq_no_resend = req->rq_no_delay = 1;
  70         }
  71         return req;
  72 }
  73
  74 int ptlrpc_obd_ping(struct obd_device *obd)
  75 {
  76         int rc;
  77         struct ptlrpc_request *req;
  78         ENTRY;
  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         ENTRY;
  98
  99         req = ptlrpc_prep_ping(imp);
 100         if (req == NULL) {
 101                 CERROR("OOM trying to ping %s->%s\n",
 102                        imp->imp_obd->obd_uuid.uuid,
 103                        obd2cli_tgt(imp->imp_obd));
 104                 RETURN(-ENOMEM);
 105         }
 106
 107         DEBUG_REQ(D_INFO, req, "pinging %s->%s",
 108                   imp->imp_obd->obd_uuid.uuid, obd2cli_tgt(imp->imp_obd));
 109         ptlrpcd_add_req(req);
 110
 111         RETURN(0);
 112 }
 113
 114 static void ptlrpc_update_next_ping(struct obd_import *imp, int soon)
 115 {
 116 #ifdef ENABLE_PINGER
 117         int time = soon ? PING_INTERVAL_SHORT : PING_INTERVAL;
 118         if (imp->imp_state == LUSTRE_IMP_DISCON) {
 119                 int dtime = max_t(int, CONNECTION_SWITCH_MIN,
 120                                   AT_OFF ? 0 :
 121                                   at_get(&imp->imp_at.iat_net_latency));
 122                 time = min(time, dtime);
 123         }
 124         imp->imp_next_ping = cfs_time_shift(time);
 125 #endif /* ENABLE_PINGER */
 126 }
 127
 128 void ptlrpc_ping_import_soon(struct obd_import *imp)
 129 {
 130         imp->imp_next_ping = cfs_time_current();
 131 }
 132
 133 static inline int imp_is_deactive(struct obd_import *imp)
 134 {
 135         return (imp->imp_deactive ||
 136                 OBD_FAIL_CHECK(OBD_FAIL_PTLRPC_IMP_DEACTIVE));
 137 }
 138
 139 static inline int ptlrpc_next_reconnect(struct obd_import *imp)
 140 {
 141         if (imp->imp_server_timeout)
 142                 return cfs_time_shift(obd_timeout / 2);
 143         else
 144                 return cfs_time_shift(obd_timeout);
 145 }
 146
 147 static cfs_duration_t pinger_check_timeout(cfs_time_t time)
 148 {
 149         struct timeout_item *item;
 150         cfs_time_t timeout = PING_INTERVAL;
 151
 152         /* This list is sorted in increasing timeout order */
 153         mutex_lock(&pinger_mutex);
 154         list_for_each_entry(item, &timeout_list, ti_chain) {
 155                 int ti_timeout = item->ti_timeout;
 156                 if (timeout > ti_timeout)
 157                         timeout = ti_timeout;
 158                 break;
 159         }
 160         mutex_unlock(&pinger_mutex);
 161
 162         return cfs_time_sub(cfs_time_add(time, cfs_time_seconds(timeout)),
 163                                          cfs_time_current());
 164 }
 165
 166
 167 static bool ir_up;
 168
 169 void ptlrpc_pinger_ir_up(void)
 170 {
 171         CDEBUG(D_HA, "IR up\n");
 172         ir_up = true;
 173 }
 174 EXPORT_SYMBOL(ptlrpc_pinger_ir_up);
 175
 176 void ptlrpc_pinger_ir_down(void)
 177 {
 178         CDEBUG(D_HA, "IR down\n");
 179         ir_up = false;
 180 }
 181 EXPORT_SYMBOL(ptlrpc_pinger_ir_down);
 182
 183 static void ptlrpc_pinger_process_import(struct obd_import *imp,
 184                                          unsigned long this_ping)
 185 {
 186         int level;
 187         int force;
 188         int force_next;
 189         int suppress;
 190
 191         spin_lock(&imp->imp_lock);
 192
 193         level = imp->imp_state;
 194         force = imp->imp_force_verify;
 195         force_next = imp->imp_force_next_verify;
 196         /*
 197          * This will be used below only if the import is "FULL".
 198          */
 199         suppress = ir_up && OCD_HAS_FLAG(&imp->imp_connect_data, PINGLESS);
 200
 201         imp->imp_force_verify = 0;
 202
 203         if (cfs_time_aftereq(imp->imp_next_ping - 5 * CFS_TICK, this_ping) &&
 204             !force) {
 205                 spin_unlock(&imp->imp_lock);
 206                 return;
 207         }
 208
 209         imp->imp_force_next_verify = 0;
 210
 211         spin_unlock(&imp->imp_lock);
 212
 213         CDEBUG(level == LUSTRE_IMP_FULL ? D_INFO : D_HA, "%s->%s: level %s/%u "
 214                "force %u force_next %u deactive %u pingable %u suppress %u\n",
 215                imp->imp_obd->obd_uuid.uuid, obd2cli_tgt(imp->imp_obd),
 216                ptlrpc_import_state_name(level), level, force, force_next,
 217                imp->imp_deactive, imp->imp_pingable, suppress);
 218
 219         if (level == LUSTRE_IMP_DISCON && !imp_is_deactive(imp)) {
 220                 /* wait for a while before trying recovery again */
 221                 imp->imp_next_ping = ptlrpc_next_reconnect(imp);
 222                 if (!imp->imp_no_pinger_recover)
 223                         ptlrpc_initiate_recovery(imp);
 224         } else if (level != LUSTRE_IMP_FULL ||
 225                    imp->imp_obd->obd_no_recov ||
 226                    imp_is_deactive(imp)) {
 227                 CDEBUG(D_HA, "%s->%s: not pinging (in recovery "
 228                        "or recovery disabled: %s)\n",
 229                        imp->imp_obd->obd_uuid.uuid, obd2cli_tgt(imp->imp_obd),
 230                        ptlrpc_import_state_name(level));
 231                 if (force) {
 232                         spin_lock(&imp->imp_lock);
 233                         imp->imp_force_verify = 1;
 234                         spin_unlock(&imp->imp_lock);
 235                 }
 236         } else if ((imp->imp_pingable && !suppress) || force_next || force) {
 237                 ptlrpc_ping(imp);
 238         }
 239 }
 240
 241 static int ptlrpc_pinger_main(void *arg)
 242 {
 243         struct ptlrpc_thread *thread = (struct ptlrpc_thread *)arg;
 244         ENTRY;
 245
 246         /* Record that the thread is running */
 247         thread_set_flags(thread, SVC_RUNNING);
 248         wake_up(&thread->t_ctl_waitq);
 249
 250         /* And now, loop forever, pinging as needed. */
 251         while (1) {
 252                 cfs_time_t this_ping = cfs_time_current();
 253                 struct l_wait_info lwi;
 254                 cfs_duration_t time_to_next_wake;
 255                 struct timeout_item *item;
 256                 struct list_head *iter;
 257
 258                 mutex_lock(&pinger_mutex);
 259                 list_for_each_entry(item, &timeout_list, ti_chain)
 260                         item->ti_cb(item, item->ti_cb_data);
 261
 262                 list_for_each(iter, &pinger_imports) {
 263                         struct obd_import *imp = list_entry(iter,
 264                                                             struct obd_import,
 265                                                             imp_pinger_chain);
 266
 267                         ptlrpc_pinger_process_import(imp, this_ping);
 268                         /* obd_timeout might have changed */
 269                         if (imp->imp_pingable && imp->imp_next_ping &&
 270                             cfs_time_after(imp->imp_next_ping,
 271                                            cfs_time_add(this_ping,
 272                                                         cfs_time_seconds(PING_INTERVAL))))
 273                                 ptlrpc_update_next_ping(imp, 0);
 274                 }
 275                 mutex_unlock(&pinger_mutex);
 276                 /* update memory usage info */
 277                 obd_update_maxusage();
 278
 279                 /* Wait until the next ping time, or until we're stopped. */
 280                 time_to_next_wake = pinger_check_timeout(this_ping);
 281                 /* The ping sent by ptlrpc_send_rpc may get sent out
 282                    say .01 second after this.
 283                    ptlrpc_pinger_sending_on_import will then set the
 284                    next ping time to next_ping + .01 sec, which means
 285                    we will SKIP the next ping at next_ping, and the
 286                    ping will get sent 2 timeouts from now!  Beware. */
 287                 CDEBUG(D_INFO, "next wakeup in "CFS_DURATION_T" ("
 288                        CFS_TIME_T")\n", time_to_next_wake,
 289                        cfs_time_add(this_ping,cfs_time_seconds(PING_INTERVAL)));
 290                 if (time_to_next_wake > 0) {
 291                         lwi = LWI_TIMEOUT(max_t(cfs_duration_t,
 292                                                 time_to_next_wake,
 293                                                 cfs_time_seconds(1)),
 294                                           NULL, NULL);
 295                         l_wait_event(thread->t_ctl_waitq,
 296                                      thread_is_stopping(thread) ||
 297                                      thread_is_event(thread),
 298                                      &lwi);
 299                         if (thread_test_and_clear_flags(thread, SVC_STOPPING)) {
 300                                 EXIT;
 301                                 break;
 302                         } else {
 303                                 /* woken after adding import to reset timer */
 304                                 thread_test_and_clear_flags(thread, SVC_EVENT);
 305                         }
 306                 }
 307         }
 308
 309         thread_set_flags(thread, SVC_STOPPED);
 310         wake_up(&thread->t_ctl_waitq);
 311
 312         CDEBUG(D_NET, "pinger thread exiting, process %d\n", current_pid());
 313         return 0;
 314 }
 315
 316 static struct ptlrpc_thread pinger_thread;
 317
 318 int ptlrpc_start_pinger(void)
 319 {
 320         struct l_wait_info lwi = { 0 };
 321         struct task_struct *task;
 322         int rc;
 323 #ifndef ENABLE_PINGER
 324         return 0;
 325 #endif
 326         ENTRY;
 327
 328         if (!thread_is_init(&pinger_thread) &&
 329             !thread_is_stopped(&pinger_thread))
 330                 RETURN(-EALREADY);
 331
 332         init_waitqueue_head(&pinger_thread.t_ctl_waitq);
 333
 334         strcpy(pinger_thread.t_name, "ll_ping");
 335
 336         task = kthread_run(ptlrpc_pinger_main, &pinger_thread,
 337                            pinger_thread.t_name);
 338         if (IS_ERR(task)) {
 339                 rc = PTR_ERR(task);
 340                 CERROR("cannot start pinger thread: rc = %d\n", rc);
 341                 RETURN(rc);
 342         }
 343
 344         l_wait_event(pinger_thread.t_ctl_waitq,
 345                      thread_is_running(&pinger_thread), &lwi);
 346
 347         if (suppress_pings)
 348                 CWARN("Pings will be suppressed at the request of the "
 349                       "administrator.  The configuration shall meet the "
 350                       "additional requirements described in the manual.  "
 351                       "(Search for the \"suppress_pings\" kernel module "
 352                       "parameter.)\n");
 353
 354         RETURN(0);
 355 }
 356
 357 int ptlrpc_pinger_remove_timeouts(void);
 358
 359 int ptlrpc_stop_pinger(void)
 360 {
 361         struct l_wait_info lwi = { 0 };
 362 #ifndef ENABLE_PINGER
 363         return 0;
 364 #endif
 365         ENTRY;
 366
 367         if (thread_is_init(&pinger_thread) ||
 368             thread_is_stopped(&pinger_thread))
 369                 RETURN(-EALREADY);
 370
 371         ptlrpc_pinger_remove_timeouts();
 372
 373         thread_set_flags(&pinger_thread, SVC_STOPPING);
 374         wake_up(&pinger_thread.t_ctl_waitq);
 375
 376         l_wait_event(pinger_thread.t_ctl_waitq,
 377                      thread_is_stopped(&pinger_thread), &lwi);
 378         RETURN(0);
 379 }
 380
 381 void ptlrpc_pinger_sending_on_import(struct obd_import *imp)
 382 {
 383         ptlrpc_update_next_ping(imp, 0);
 384 }
 385
 386 void ptlrpc_pinger_commit_expected(struct obd_import *imp)
 387 {
 388         ptlrpc_update_next_ping(imp, 1);
 389         assert_spin_locked(&imp->imp_lock);
 390         /*
 391          * Avoid reading stale imp_connect_data.  When not sure if pings are
 392          * expected or not on next connection, we assume they are not and force
 393          * one anyway to guarantee the chance of updating
 394          * imp_peer_committed_transno.
 395          */
 396         if (imp->imp_state != LUSTRE_IMP_FULL ||
 397             OCD_HAS_FLAG(&imp->imp_connect_data, PINGLESS))
 398                 imp->imp_force_next_verify = 1;
 399 }
 400
 401 int ptlrpc_pinger_add_import(struct obd_import *imp)
 402 {
 403         ENTRY;
 404         if (!list_empty(&imp->imp_pinger_chain))
 405                 RETURN(-EALREADY);
 406
 407         mutex_lock(&pinger_mutex);
 408         CDEBUG(D_HA, "adding pingable import %s->%s\n",
 409                imp->imp_obd->obd_uuid.uuid, obd2cli_tgt(imp->imp_obd));
 410         /* if we add to pinger we want recovery on this import */
 411         imp->imp_obd->obd_no_recov = 0;
 412         ptlrpc_update_next_ping(imp, 0);
 413         /* XXX sort, blah blah */
 414         list_add_tail(&imp->imp_pinger_chain, &pinger_imports);
 415         class_import_get(imp);
 416
 417         ptlrpc_pinger_wake_up();
 418         mutex_unlock(&pinger_mutex);
 419
 420         RETURN(0);
 421 }
 422 EXPORT_SYMBOL(ptlrpc_pinger_add_import);
 423
 424 int ptlrpc_pinger_del_import(struct obd_import *imp)
 425 {
 426         ENTRY;
 427
 428         if (list_empty(&imp->imp_pinger_chain))
 429                 RETURN(-ENOENT);
 430
 431         mutex_lock(&pinger_mutex);
 432         list_del_init(&imp->imp_pinger_chain);
 433         CDEBUG(D_HA, "removing pingable import %s->%s\n",
 434                imp->imp_obd->obd_uuid.uuid, obd2cli_tgt(imp->imp_obd));
 435         /* if we remove from pinger we don't want recovery on this import */
 436         imp->imp_obd->obd_no_recov = 1;
 437         class_import_put(imp);
 438         mutex_unlock(&pinger_mutex);
 439         RETURN(0);
 440 }
 441 EXPORT_SYMBOL(ptlrpc_pinger_del_import);
 442
 443 /**
 444  * Register a timeout callback to the pinger list, and the callback will
 445  * be called when timeout happens.
 446  */
 447 static struct timeout_item *ptlrpc_new_timeout(int time,
 448                                                enum timeout_event event,
 449                                                timeout_cb_t cb, void *data)
 450 {
 451         struct timeout_item *ti;
 452
 453         OBD_ALLOC_PTR(ti);
 454         if (!ti)
 455                 return(NULL);
 456
 457         INIT_LIST_HEAD(&ti->ti_obd_list);
 458         INIT_LIST_HEAD(&ti->ti_chain);
 459         ti->ti_timeout = time;
 460         ti->ti_event = event;
 461         ti->ti_cb = cb;
 462         ti->ti_cb_data = data;
 463
 464         return ti;
 465 }
 466
 467 /**
 468  * Register timeout event on the the pinger thread.
 469  * Note: the timeout list is an sorted list with increased timeout value.
 470  */
 471 static struct timeout_item*
 472 ptlrpc_pinger_register_timeout(int time, enum timeout_event event,
 473                                timeout_cb_t cb, void *data)
 474 {
 475         struct timeout_item *item, *tmp;
 476
 477         LASSERT(mutex_is_locked(&pinger_mutex));
 478
 479         list_for_each_entry(item, &timeout_list, ti_chain)
 480                 if (item->ti_event == event)
 481                         goto out;
 482
 483         item = ptlrpc_new_timeout(time, event, cb, data);
 484         if (item) {
 485                 list_for_each_entry_reverse(tmp, &timeout_list, ti_chain) {
 486                         if (tmp->ti_timeout < time) {
 487                                 list_add(&item->ti_chain, &tmp->ti_chain);
 488                                 goto out;
 489                         }
 490                 }
 491                 list_add(&item->ti_chain, &timeout_list);
 492         }
 493 out:
 494         return item;
 495 }
 496
 497 /* Add a client_obd to the timeout event list, when timeout(@time)
 498  * happens, the callback(@cb) will be called.
 499  */
 500 int ptlrpc_add_timeout_client(int time, enum timeout_event event,
 501                               timeout_cb_t cb, void *data,
 502                               struct list_head *obd_list)
 503 {
 504         struct timeout_item *ti;
 505
 506         mutex_lock(&pinger_mutex);
 507         ti = ptlrpc_pinger_register_timeout(time, event, cb, data);
 508         if (!ti) {
 509                 mutex_unlock(&pinger_mutex);
 510                 return (-EINVAL);
 511         }
 512         list_add(obd_list, &ti->ti_obd_list);
 513         mutex_unlock(&pinger_mutex);
 514         return 0;
 515 }
 516 EXPORT_SYMBOL(ptlrpc_add_timeout_client);
 517
 518 int ptlrpc_del_timeout_client(struct list_head *obd_list,
 519                               enum timeout_event event)
 520 {
 521         struct timeout_item *ti = NULL, *item;
 522
 523         if (list_empty(obd_list))
 524                 return 0;
 525         mutex_lock(&pinger_mutex);
 526         list_del_init(obd_list);
 527         /**
 528          * If there are no obd attached to the timeout event
 529          * list, remove this timeout event from the pinger
 530          */
 531         list_for_each_entry(item, &timeout_list, ti_chain) {
 532                 if (item->ti_event == event) {
 533                         ti = item;
 534                         break;
 535                 }
 536         }
 537         LASSERTF(ti != NULL, "ti is NULL !\n");
 538         if (list_empty(&ti->ti_obd_list)) {
 539                 list_del(&ti->ti_chain);
 540                 OBD_FREE_PTR(ti);
 541         }
 542         mutex_unlock(&pinger_mutex);
 543         return 0;
 544 }
 545 EXPORT_SYMBOL(ptlrpc_del_timeout_client);
 546
 547 int ptlrpc_pinger_remove_timeouts(void)
 548 {
 549         struct timeout_item *item, *tmp;
 550
 551         mutex_lock(&pinger_mutex);
 552         list_for_each_entry_safe(item, tmp, &timeout_list, ti_chain) {
 553                 LASSERT(list_empty(&item->ti_obd_list));
 554                 list_del(&item->ti_chain);
 555                 OBD_FREE_PTR(item);
 556         }
 557         mutex_unlock(&pinger_mutex);
 558         return 0;
 559 }
 560
 561 void ptlrpc_pinger_wake_up()
 562 {
 563 #ifdef ENABLE_PINGER
 564         thread_add_flags(&pinger_thread, SVC_EVENT);
 565         wake_up(&pinger_thread.t_ctl_waitq);
 566 #endif
 567 }
 568
 569 /* Ping evictor thread */
 570 #define PET_READY     1
 571 #define PET_TERMINATE 2
 572
 573 static int               pet_refcount = 0;
 574 static int               pet_state;
 575 static wait_queue_head_t pet_waitq;
 576 static struct list_head  pet_list;
 577 static DEFINE_SPINLOCK(pet_lock);
 578
 579 int ping_evictor_wake(struct obd_export *exp)
 580 {
 581         struct obd_device *obd;
 582
 583         spin_lock(&pet_lock);
 584         if (pet_state != PET_READY) {
 585                 /* eventually the new obd will call here again. */
 586                 spin_unlock(&pet_lock);
 587                 return 1;
 588         }
 589
 590         obd = class_exp2obd(exp);
 591         if (list_empty(&obd->obd_evict_list)) {
 592                 class_incref(obd, "evictor", obd);
 593                 list_add(&obd->obd_evict_list, &pet_list);
 594         }
 595         spin_unlock(&pet_lock);
 596
 597         wake_up(&pet_waitq);
 598         return 0;
 599 }
 600
 601 static int ping_evictor_main(void *arg)
 602 {
 603         struct obd_device *obd;
 604         struct obd_export *exp;
 605         struct l_wait_info lwi = { 0 };
 606         time_t expire_time;
 607         ENTRY;
 608
 609         unshare_fs_struct();
 610
 611         CDEBUG(D_HA, "Starting Ping Evictor\n");
 612         pet_state = PET_READY;
 613         while (1) {
 614                 l_wait_event(pet_waitq, (!list_empty(&pet_list)) ||
 615                             (pet_state == PET_TERMINATE), &lwi);
 616
 617                 /* loop until all obd's will be removed */
 618                 if ((pet_state == PET_TERMINATE) && list_empty(&pet_list))
 619                         break;
 620
 621                 /* we only get here if pet_exp != NULL, and the end of this
 622                  * loop is the only place which sets it NULL again, so lock
 623                  * is not strictly necessary. */
 624                 spin_lock(&pet_lock);
 625                 obd = list_entry(pet_list.next, struct obd_device,
 626                                  obd_evict_list);
 627                 spin_unlock(&pet_lock);
 628
 629                 expire_time = cfs_time_current_sec() - PING_EVICT_TIMEOUT;
 630
 631                 CDEBUG(D_HA, "evicting all exports of obd %s older than %ld\n",
 632                        obd->obd_name, expire_time);
 633
 634                 /* Exports can't be deleted out of the list while we hold
 635                  * the obd lock (class_unlink_export), which means we can't
 636                  * lose the last ref on the export.  If they've already been
 637                  * removed from the list, we won't find them here. */
 638                 spin_lock(&obd->obd_dev_lock);
 639                 while (!list_empty(&obd->obd_exports_timed)) {
 640                         exp = list_entry(obd->obd_exports_timed.next,
 641                                          struct obd_export,
 642                                          exp_obd_chain_timed);
 643                         if (expire_time > exp->exp_last_request_time) {
 644                                 class_export_get(exp);
 645                                 spin_unlock(&obd->obd_dev_lock);
 646                                 LCONSOLE_WARN("%s: haven't heard from client %s"
 647                                               " (at %s) in %ld seconds. I think"
 648                                               " it's dead, and I am evicting"
 649                                               " it. exp %p, cur %ld expire %ld"
 650                                               " last %ld\n",
 651                                               obd->obd_name,
 652                                               obd_uuid2str(&exp->exp_client_uuid),
 653                                               obd_export_nid2str(exp),
 654                                               (long)(cfs_time_current_sec() -
 655                                                      exp->exp_last_request_time),
 656                                               exp, (long)cfs_time_current_sec(),
 657                                               (long)expire_time,
 658                                               (long)exp->exp_last_request_time);
 659                                 CDEBUG(D_HA, "Last request was at %ld\n",
 660                                        exp->exp_last_request_time);
 661                                 class_fail_export(exp);
 662                                 class_export_put(exp);
 663                                 spin_lock(&obd->obd_dev_lock);
 664                         } else {
 665                                 /* List is sorted, so everyone below is ok */
 666                                 break;
 667                         }
 668                 }
 669                 spin_unlock(&obd->obd_dev_lock);
 670
 671                 spin_lock(&pet_lock);
 672                 list_del_init(&obd->obd_evict_list);
 673                 spin_unlock(&pet_lock);
 674
 675                 class_decref(obd, "evictor", obd);
 676         }
 677         CDEBUG(D_HA, "Exiting Ping Evictor\n");
 678
 679         RETURN(0);
 680 }
 681
 682 void ping_evictor_start(void)
 683 {
 684         struct task_struct *task;
 685
 686         if (++pet_refcount > 1)
 687                 return;
 688
 689         INIT_LIST_HEAD(&pet_list);
 690         init_waitqueue_head(&pet_waitq);
 691
 692         task = kthread_run(ping_evictor_main, NULL, "ll_evictor");
 693         if (IS_ERR(task)) {
 694                 pet_refcount--;
 695                 CERROR("Cannot start ping evictor thread: %ld\n",
 696                         PTR_ERR(task));
 697         }
 698 }
 699 EXPORT_SYMBOL(ping_evictor_start);
 700
 701 void ping_evictor_stop(void)
 702 {
 703         if (--pet_refcount > 0)
 704                 return;
 705
 706         pet_state = PET_TERMINATE;
 707         wake_up(&pet_waitq);
 708 }
 709 EXPORT_SYMBOL(ping_evictor_stop);