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, 2014, 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 <obd_support.h>
  44 #include <obd_class.h>
  45 #include "ptlrpc_internal.h"
  46
  47 static int suppress_pings;
  48 CFS_MODULE_PARM(suppress_pings, "i", int, 0644, "Suppress pings");
  49
  50 struct mutex pinger_mutex;
  51 static struct list_head pinger_imports =
  52                 LIST_HEAD_INIT(pinger_imports);
  53 static struct list_head timeout_list =
  54                 LIST_HEAD_INIT(timeout_list);
  55
  56 int ptlrpc_pinger_suppress_pings()
  57 {
  58         return suppress_pings;
  59 }
  60 EXPORT_SYMBOL(ptlrpc_pinger_suppress_pings);
  61
  62 struct ptlrpc_request *
  63 ptlrpc_prep_ping(struct obd_import *imp)
  64 {
  65         struct ptlrpc_request *req;
  66
  67         req = ptlrpc_request_alloc_pack(imp, &RQF_OBD_PING,
  68                                         LUSTRE_OBD_VERSION, OBD_PING);
  69         if (req) {
  70                 ptlrpc_request_set_replen(req);
  71                 req->rq_no_resend = req->rq_no_delay = 1;
  72         }
  73         return req;
  74 }
  75
  76 int ptlrpc_obd_ping(struct obd_device *obd)
  77 {
  78         int rc;
  79         struct ptlrpc_request *req;
  80         ENTRY;
  81
  82         req = ptlrpc_prep_ping(obd->u.cli.cl_import);
  83         if (req == NULL)
  84                 RETURN(-ENOMEM);
  85
  86         req->rq_send_state = LUSTRE_IMP_FULL;
  87
  88         rc = ptlrpc_queue_wait(req);
  89
  90         ptlrpc_req_finished(req);
  91
  92         RETURN(rc);
  93 }
  94 EXPORT_SYMBOL(ptlrpc_obd_ping);
  95
  96 static int ptlrpc_ping(struct obd_import *imp)
  97 {
  98         struct ptlrpc_request *req;
  99         ENTRY;
 100
 101         req = ptlrpc_prep_ping(imp);
 102         if (req == NULL) {
 103                 CERROR("OOM trying to ping %s->%s\n",
 104                        imp->imp_obd->obd_uuid.uuid,
 105                        obd2cli_tgt(imp->imp_obd));
 106                 RETURN(-ENOMEM);
 107         }
 108
 109         DEBUG_REQ(D_INFO, req, "pinging %s->%s",
 110                   imp->imp_obd->obd_uuid.uuid, obd2cli_tgt(imp->imp_obd));
 111         ptlrpcd_add_req(req, PDL_POLICY_ROUND, -1);
 112
 113         RETURN(0);
 114 }
 115
 116 static void ptlrpc_update_next_ping(struct obd_import *imp, int soon)
 117 {
 118 #ifdef ENABLE_PINGER
 119         int time = soon ? PING_INTERVAL_SHORT : PING_INTERVAL;
 120         if (imp->imp_state == LUSTRE_IMP_DISCON) {
 121                 int dtime = max_t(int, CONNECTION_SWITCH_MIN,
 122                                   AT_OFF ? 0 :
 123                                   at_get(&imp->imp_at.iat_net_latency));
 124                 time = min(time, dtime);
 125         }
 126         imp->imp_next_ping = cfs_time_shift(time);
 127 #endif /* ENABLE_PINGER */
 128 }
 129
 130 void ptlrpc_ping_import_soon(struct obd_import *imp)
 131 {
 132         imp->imp_next_ping = cfs_time_current();
 133 }
 134
 135 static inline int imp_is_deactive(struct obd_import *imp)
 136 {
 137         return (imp->imp_deactive ||
 138                 OBD_FAIL_CHECK(OBD_FAIL_PTLRPC_IMP_DEACTIVE));
 139 }
 140
 141 static inline int ptlrpc_next_reconnect(struct obd_import *imp)
 142 {
 143         if (imp->imp_server_timeout)
 144                 return cfs_time_shift(obd_timeout / 2);
 145         else
 146                 return cfs_time_shift(obd_timeout);
 147 }
 148
 149 static cfs_duration_t pinger_check_timeout(cfs_time_t time)
 150 {
 151         struct timeout_item *item;
 152         cfs_time_t timeout = PING_INTERVAL;
 153
 154         /* The timeout list is a increase order sorted list */
 155         mutex_lock(&pinger_mutex);
 156         list_for_each_entry(item, &timeout_list, ti_chain) {
 157                 int ti_timeout = item->ti_timeout;
 158                 if (timeout > ti_timeout)
 159                         timeout = ti_timeout;
 160                 break;
 161         }
 162         mutex_unlock(&pinger_mutex);
 163
 164         return cfs_time_sub(cfs_time_add(time, cfs_time_seconds(timeout)),
 165                                          cfs_time_current());
 166 }
 167
 168
 169 static bool ir_up;
 170
 171 void ptlrpc_pinger_ir_up(void)
 172 {
 173         CDEBUG(D_HA, "IR up\n");
 174         ir_up = true;
 175 }
 176 EXPORT_SYMBOL(ptlrpc_pinger_ir_up);
 177
 178 void ptlrpc_pinger_ir_down(void)
 179 {
 180         CDEBUG(D_HA, "IR down\n");
 181         ir_up = false;
 182 }
 183 EXPORT_SYMBOL(ptlrpc_pinger_ir_down);
 184
 185 static void ptlrpc_pinger_process_import(struct obd_import *imp,
 186                                          unsigned long this_ping)
 187 {
 188         int level;
 189         int force;
 190         int force_next;
 191         int suppress;
 192
 193         spin_lock(&imp->imp_lock);
 194
 195         level = imp->imp_state;
 196         force = imp->imp_force_verify;
 197         force_next = imp->imp_force_next_verify;
 198         /*
 199          * This will be used below only if the import is "FULL".
 200          */
 201         suppress = ir_up && OCD_HAS_FLAG(&imp->imp_connect_data, PINGLESS);
 202
 203         imp->imp_force_verify = 0;
 204
 205         if (cfs_time_aftereq(imp->imp_next_ping - 5 * CFS_TICK, this_ping) &&
 206             !force) {
 207                 spin_unlock(&imp->imp_lock);
 208                 return;
 209         }
 210
 211         imp->imp_force_next_verify = 0;
 212
 213         spin_unlock(&imp->imp_lock);
 214
 215         CDEBUG(level == LUSTRE_IMP_FULL ? D_INFO : D_HA, "%s->%s: level %s/%u "
 216                "force %u force_next %u deactive %u pingable %u suppress %u\n",
 217                imp->imp_obd->obd_uuid.uuid, obd2cli_tgt(imp->imp_obd),
 218                ptlrpc_import_state_name(level), level, force, force_next,
 219                imp->imp_deactive, imp->imp_pingable, suppress);
 220
 221         if (level == LUSTRE_IMP_DISCON && !imp_is_deactive(imp)) {
 222                 /* wait for a while before trying recovery again */
 223                 imp->imp_next_ping = ptlrpc_next_reconnect(imp);
 224                 if (!imp->imp_no_pinger_recover)
 225                         ptlrpc_initiate_recovery(imp);
 226         } else if (level != LUSTRE_IMP_FULL ||
 227                    imp->imp_obd->obd_no_recov ||
 228                    imp_is_deactive(imp)) {
 229                 CDEBUG(D_HA, "%s->%s: not pinging (in recovery "
 230                        "or recovery disabled: %s)\n",
 231                        imp->imp_obd->obd_uuid.uuid, obd2cli_tgt(imp->imp_obd),
 232                        ptlrpc_import_state_name(level));
 233                 if (force) {
 234                         spin_lock(&imp->imp_lock);
 235                         imp->imp_force_verify = 1;
 236                         spin_unlock(&imp->imp_lock);
 237                 }
 238         } else if ((imp->imp_pingable && !suppress) || force_next || force) {
 239                 ptlrpc_ping(imp);
 240         }
 241 }
 242
 243 static int ptlrpc_pinger_main(void *arg)
 244 {
 245         struct ptlrpc_thread *thread = (struct ptlrpc_thread *)arg;
 246         ENTRY;
 247
 248         /* Record that the thread is running */
 249         thread_set_flags(thread, SVC_RUNNING);
 250         wake_up(&thread->t_ctl_waitq);
 251
 252         /* And now, loop forever, pinging as needed. */
 253         while (1) {
 254                 cfs_time_t this_ping = cfs_time_current();
 255                 struct l_wait_info lwi;
 256                 cfs_duration_t time_to_next_wake;
 257                 struct timeout_item *item;
 258                 struct list_head *iter;
 259
 260                 mutex_lock(&pinger_mutex);
 261                 list_for_each_entry(item, &timeout_list, ti_chain)
 262                         item->ti_cb(item, item->ti_cb_data);
 263
 264                 list_for_each(iter, &pinger_imports) {
 265                         struct obd_import *imp = list_entry(iter,
 266                                                             struct obd_import,
 267                                                             imp_pinger_chain);
 268
 269                         ptlrpc_pinger_process_import(imp, this_ping);
 270                         /* obd_timeout might have changed */
 271                         if (imp->imp_pingable && imp->imp_next_ping &&
 272                             cfs_time_after(imp->imp_next_ping,
 273                                            cfs_time_add(this_ping,
 274                                                         cfs_time_seconds(PING_INTERVAL))))
 275                                 ptlrpc_update_next_ping(imp, 0);
 276                 }
 277                 mutex_unlock(&pinger_mutex);
 278                 /* update memory usage info */
 279                 obd_update_maxusage();
 280
 281                 /* Wait until the next ping time, or until we're stopped. */
 282                 time_to_next_wake = pinger_check_timeout(this_ping);
 283                 /* The ping sent by ptlrpc_send_rpc may get sent out
 284                    say .01 second after this.
 285                    ptlrpc_pinger_sending_on_import will then set the
 286                    next ping time to next_ping + .01 sec, which means
 287                    we will SKIP the next ping at next_ping, and the
 288                    ping will get sent 2 timeouts from now!  Beware. */
 289                 CDEBUG(D_INFO, "next wakeup in "CFS_DURATION_T" ("
 290                        CFS_TIME_T")\n", time_to_next_wake,
 291                        cfs_time_add(this_ping,cfs_time_seconds(PING_INTERVAL)));
 292                 if (time_to_next_wake > 0) {
 293                         lwi = LWI_TIMEOUT(max_t(cfs_duration_t,
 294                                                 time_to_next_wake,
 295                                                 cfs_time_seconds(1)),
 296                                           NULL, NULL);
 297                         l_wait_event(thread->t_ctl_waitq,
 298                                      thread_is_stopping(thread) ||
 299                                      thread_is_event(thread),
 300                                      &lwi);
 301                         if (thread_test_and_clear_flags(thread, SVC_STOPPING)) {
 302                                 EXIT;
 303                                 break;
 304                         } else {
 305                                 /* woken after adding import to reset timer */
 306                                 thread_test_and_clear_flags(thread, SVC_EVENT);
 307                         }
 308                 }
 309         }
 310
 311         thread_set_flags(thread, SVC_STOPPED);
 312         wake_up(&thread->t_ctl_waitq);
 313
 314         CDEBUG(D_NET, "pinger thread exiting, process %d\n", current_pid());
 315         return 0;
 316 }
 317
 318 static struct ptlrpc_thread pinger_thread;
 319
 320 int ptlrpc_start_pinger(void)
 321 {
 322         struct l_wait_info lwi = { 0 };
 323         struct task_struct *task;
 324         int rc;
 325 #ifndef ENABLE_PINGER
 326         return 0;
 327 #endif
 328         ENTRY;
 329
 330         if (!thread_is_init(&pinger_thread) &&
 331             !thread_is_stopped(&pinger_thread))
 332                 RETURN(-EALREADY);
 333
 334         init_waitqueue_head(&pinger_thread.t_ctl_waitq);
 335
 336         strcpy(pinger_thread.t_name, "ll_ping");
 337
 338         /* CLONE_VM and CLONE_FILES just avoid a needless copy, because we
 339          * just drop the VM and FILES in kthread_run() right away. */
 340         task = kthread_run(ptlrpc_pinger_main, &pinger_thread,
 341                            pinger_thread.t_name);
 342         if (IS_ERR(task)) {
 343                 rc = PTR_ERR(task);
 344                 CERROR("cannot start pinger thread: rc = %d\n", rc);
 345                 RETURN(rc);
 346         }
 347
 348         l_wait_event(pinger_thread.t_ctl_waitq,
 349                      thread_is_running(&pinger_thread), &lwi);
 350
 351         if (suppress_pings)
 352                 CWARN("Pings will be suppressed at the request of the "
 353                       "administrator.  The configuration shall meet the "
 354                       "additional requirements described in the manual.  "
 355                       "(Search for the \"suppress_pings\" kernel module "
 356                       "parameter.)\n");
 357
 358         RETURN(0);
 359 }
 360
 361 int ptlrpc_pinger_remove_timeouts(void);
 362
 363 int ptlrpc_stop_pinger(void)
 364 {
 365         struct l_wait_info lwi = { 0 };
 366 #ifndef ENABLE_PINGER
 367         return 0;
 368 #endif
 369         ENTRY;
 370
 371         if (thread_is_init(&pinger_thread) ||
 372             thread_is_stopped(&pinger_thread))
 373                 RETURN(-EALREADY);
 374
 375         ptlrpc_pinger_remove_timeouts();
 376
 377         thread_set_flags(&pinger_thread, SVC_STOPPING);
 378         wake_up(&pinger_thread.t_ctl_waitq);
 379
 380         l_wait_event(pinger_thread.t_ctl_waitq,
 381                      thread_is_stopped(&pinger_thread), &lwi);
 382         RETURN(0);
 383 }
 384
 385 void ptlrpc_pinger_sending_on_import(struct obd_import *imp)
 386 {
 387         ptlrpc_update_next_ping(imp, 0);
 388 }
 389
 390 void ptlrpc_pinger_commit_expected(struct obd_import *imp)
 391 {
 392         ptlrpc_update_next_ping(imp, 1);
 393         assert_spin_locked(&imp->imp_lock);
 394         /*
 395          * Avoid reading stale imp_connect_data.  When not sure if pings are
 396          * expected or not on next connection, we assume they are not and force
 397          * one anyway to guarantee the chance of updating
 398          * imp_peer_committed_transno.
 399          */
 400         if (imp->imp_state != LUSTRE_IMP_FULL ||
 401             OCD_HAS_FLAG(&imp->imp_connect_data, PINGLESS))
 402                 imp->imp_force_next_verify = 1;
 403 }
 404
 405 int ptlrpc_pinger_add_import(struct obd_import *imp)
 406 {
 407         ENTRY;
 408         if (!list_empty(&imp->imp_pinger_chain))
 409                 RETURN(-EALREADY);
 410
 411         mutex_lock(&pinger_mutex);
 412         CDEBUG(D_HA, "adding pingable import %s->%s\n",
 413                imp->imp_obd->obd_uuid.uuid, obd2cli_tgt(imp->imp_obd));
 414         /* if we add to pinger we want recovery on this import */
 415         imp->imp_obd->obd_no_recov = 0;
 416         ptlrpc_update_next_ping(imp, 0);
 417         /* XXX sort, blah blah */
 418         list_add_tail(&imp->imp_pinger_chain, &pinger_imports);
 419         class_import_get(imp);
 420
 421         ptlrpc_pinger_wake_up();
 422         mutex_unlock(&pinger_mutex);
 423
 424         RETURN(0);
 425 }
 426 EXPORT_SYMBOL(ptlrpc_pinger_add_import);
 427
 428 int ptlrpc_pinger_del_import(struct obd_import *imp)
 429 {
 430         ENTRY;
 431
 432         if (list_empty(&imp->imp_pinger_chain))
 433                 RETURN(-ENOENT);
 434
 435         mutex_lock(&pinger_mutex);
 436         list_del_init(&imp->imp_pinger_chain);
 437         CDEBUG(D_HA, "removing pingable import %s->%s\n",
 438                imp->imp_obd->obd_uuid.uuid, obd2cli_tgt(imp->imp_obd));
 439         /* if we remove from pinger we don't want recovery on this import */
 440         imp->imp_obd->obd_no_recov = 1;
 441         class_import_put(imp);
 442         mutex_unlock(&pinger_mutex);
 443         RETURN(0);
 444 }
 445 EXPORT_SYMBOL(ptlrpc_pinger_del_import);
 446
 447 /**
 448  * Register a timeout callback to the pinger list, and the callback will
 449  * be called when timeout happens.
 450  */
 451 static struct timeout_item *ptlrpc_new_timeout(int time,
 452                                                enum timeout_event event,
 453                                                timeout_cb_t cb, void *data)
 454 {
 455         struct timeout_item *ti;
 456
 457         OBD_ALLOC_PTR(ti);
 458         if (!ti)
 459                 return(NULL);
 460
 461         INIT_LIST_HEAD(&ti->ti_obd_list);
 462         INIT_LIST_HEAD(&ti->ti_chain);
 463         ti->ti_timeout = time;
 464         ti->ti_event = event;
 465         ti->ti_cb = cb;
 466         ti->ti_cb_data = data;
 467
 468         return ti;
 469 }
 470
 471 /**
 472  * Register timeout event on the the pinger thread.
 473  * Note: the timeout list is an sorted list with increased timeout value.
 474  */
 475 static struct timeout_item*
 476 ptlrpc_pinger_register_timeout(int time, enum timeout_event event,
 477                                timeout_cb_t cb, void *data)
 478 {
 479         struct timeout_item *item, *tmp;
 480
 481         LASSERT(mutex_is_locked(&pinger_mutex));
 482
 483         list_for_each_entry(item, &timeout_list, ti_chain)
 484                 if (item->ti_event == event)
 485                         goto out;
 486
 487         item = ptlrpc_new_timeout(time, event, cb, data);
 488         if (item) {
 489                 list_for_each_entry_reverse(tmp, &timeout_list, ti_chain) {
 490                         if (tmp->ti_timeout < time) {
 491                                 list_add(&item->ti_chain, &tmp->ti_chain);
 492                                 goto out;
 493                         }
 494                 }
 495                 list_add(&item->ti_chain, &timeout_list);
 496         }
 497 out:
 498         return item;
 499 }
 500
 501 /* Add a client_obd to the timeout event list, when timeout(@time)
 502  * happens, the callback(@cb) will be called.
 503  */
 504 int ptlrpc_add_timeout_client(int time, enum timeout_event event,
 505                               timeout_cb_t cb, void *data,
 506                               struct list_head *obd_list)
 507 {
 508         struct timeout_item *ti;
 509
 510         mutex_lock(&pinger_mutex);
 511         ti = ptlrpc_pinger_register_timeout(time, event, cb, data);
 512         if (!ti) {
 513                 mutex_unlock(&pinger_mutex);
 514                 return (-EINVAL);
 515         }
 516         list_add(obd_list, &ti->ti_obd_list);
 517         mutex_unlock(&pinger_mutex);
 518         return 0;
 519 }
 520 EXPORT_SYMBOL(ptlrpc_add_timeout_client);
 521
 522 int ptlrpc_del_timeout_client(struct list_head *obd_list,
 523                               enum timeout_event event)
 524 {
 525         struct timeout_item *ti = NULL, *item;
 526
 527         if (list_empty(obd_list))
 528                 return 0;
 529         mutex_lock(&pinger_mutex);
 530         list_del_init(obd_list);
 531         /**
 532          * If there are no obd attached to the timeout event
 533          * list, remove this timeout event from the pinger
 534          */
 535         list_for_each_entry(item, &timeout_list, ti_chain) {
 536                 if (item->ti_event == event) {
 537                         ti = item;
 538                         break;
 539                 }
 540         }
 541         LASSERTF(ti != NULL, "ti is NULL !\n");
 542         if (list_empty(&ti->ti_obd_list)) {
 543                 list_del(&ti->ti_chain);
 544                 OBD_FREE_PTR(ti);
 545         }
 546         mutex_unlock(&pinger_mutex);
 547         return 0;
 548 }
 549 EXPORT_SYMBOL(ptlrpc_del_timeout_client);
 550
 551 int ptlrpc_pinger_remove_timeouts(void)
 552 {
 553         struct timeout_item *item, *tmp;
 554
 555         mutex_lock(&pinger_mutex);
 556         list_for_each_entry_safe(item, tmp, &timeout_list, ti_chain) {
 557                 LASSERT(list_empty(&item->ti_obd_list));
 558                 list_del(&item->ti_chain);
 559                 OBD_FREE_PTR(item);
 560         }
 561         mutex_unlock(&pinger_mutex);
 562         return 0;
 563 }
 564
 565 void ptlrpc_pinger_wake_up()
 566 {
 567 #ifdef ENABLE_PINGER
 568         thread_add_flags(&pinger_thread, SVC_EVENT);
 569         wake_up(&pinger_thread.t_ctl_waitq);
 570 #endif
 571 }
 572
 573 /* Ping evictor thread */
 574 #define PET_READY     1
 575 #define PET_TERMINATE 2
 576
 577 static int               pet_refcount = 0;
 578 static int               pet_state;
 579 static wait_queue_head_t pet_waitq;
 580 static struct list_head  pet_list;
 581 static DEFINE_SPINLOCK(pet_lock);
 582
 583 int ping_evictor_wake(struct obd_export *exp)
 584 {
 585         struct obd_device *obd;
 586
 587         spin_lock(&pet_lock);
 588         if (pet_state != PET_READY) {
 589                 /* eventually the new obd will call here again. */
 590                 spin_unlock(&pet_lock);
 591                 return 1;
 592         }
 593
 594         obd = class_exp2obd(exp);
 595         if (list_empty(&obd->obd_evict_list)) {
 596                 class_incref(obd, "evictor", obd);
 597                 list_add(&obd->obd_evict_list, &pet_list);
 598         }
 599         spin_unlock(&pet_lock);
 600
 601         wake_up(&pet_waitq);
 602         return 0;
 603 }
 604
 605 static int ping_evictor_main(void *arg)
 606 {
 607         struct obd_device *obd;
 608         struct obd_export *exp;
 609         struct l_wait_info lwi = { 0 };
 610         time_t expire_time;
 611         ENTRY;
 612
 613         unshare_fs_struct();
 614
 615         CDEBUG(D_HA, "Starting Ping Evictor\n");
 616         pet_state = PET_READY;
 617         while (1) {
 618                 l_wait_event(pet_waitq, (!list_empty(&pet_list)) ||
 619                             (pet_state == PET_TERMINATE), &lwi);
 620
 621                 /* loop until all obd's will be removed */
 622                 if ((pet_state == PET_TERMINATE) && list_empty(&pet_list))
 623                         break;
 624
 625                 /* we only get here if pet_exp != NULL, and the end of this
 626                  * loop is the only place which sets it NULL again, so lock
 627                  * is not strictly necessary. */
 628                 spin_lock(&pet_lock);
 629                 obd = list_entry(pet_list.next, struct obd_device,
 630                                  obd_evict_list);
 631                 spin_unlock(&pet_lock);
 632
 633                 expire_time = cfs_time_current_sec() - PING_EVICT_TIMEOUT;
 634
 635                 CDEBUG(D_HA, "evicting all exports of obd %s older than %ld\n",
 636                        obd->obd_name, expire_time);
 637
 638                 /* Exports can't be deleted out of the list while we hold
 639                  * the obd lock (class_unlink_export), which means we can't
 640                  * lose the last ref on the export.  If they've already been
 641                  * removed from the list, we won't find them here. */
 642                 spin_lock(&obd->obd_dev_lock);
 643                 while (!list_empty(&obd->obd_exports_timed)) {
 644                         exp = list_entry(obd->obd_exports_timed.next,
 645                                          struct obd_export,
 646                                          exp_obd_chain_timed);
 647                         if (expire_time > exp->exp_last_request_time) {
 648                                 class_export_get(exp);
 649                                 spin_unlock(&obd->obd_dev_lock);
 650                                 LCONSOLE_WARN("%s: haven't heard from client %s"
 651                                               " (at %s) in %ld seconds. I think"
 652                                               " it's dead, and I am evicting"
 653                                               " it. exp %p, cur %ld expire %ld"
 654                                               " last %ld\n",
 655                                               obd->obd_name,
 656                                               obd_uuid2str(&exp->exp_client_uuid),
 657                                               obd_export_nid2str(exp),
 658                                               (long)(cfs_time_current_sec() -
 659                                                      exp->exp_last_request_time),
 660                                               exp, (long)cfs_time_current_sec(),
 661                                               (long)expire_time,
 662                                               (long)exp->exp_last_request_time);
 663                                 CDEBUG(D_HA, "Last request was at %ld\n",
 664                                        exp->exp_last_request_time);
 665                                 class_fail_export(exp);
 666                                 class_export_put(exp);
 667                                 spin_lock(&obd->obd_dev_lock);
 668                         } else {
 669                                 /* List is sorted, so everyone below is ok */
 670                                 break;
 671                         }
 672                 }
 673                 spin_unlock(&obd->obd_dev_lock);
 674
 675                 spin_lock(&pet_lock);
 676                 list_del_init(&obd->obd_evict_list);
 677                 spin_unlock(&pet_lock);
 678
 679                 class_decref(obd, "evictor", obd);
 680         }
 681         CDEBUG(D_HA, "Exiting Ping Evictor\n");
 682
 683         RETURN(0);
 684 }
 685
 686 void ping_evictor_start(void)
 687 {
 688         struct task_struct *task;
 689
 690         if (++pet_refcount > 1)
 691                 return;
 692
 693         INIT_LIST_HEAD(&pet_list);
 694         init_waitqueue_head(&pet_waitq);
 695
 696         task = kthread_run(ping_evictor_main, NULL, "ll_evictor");
 697         if (IS_ERR(task)) {
 698                 pet_refcount--;
 699                 CERROR("Cannot start ping evictor thread: %ld\n",
 700                         PTR_ERR(task));
 701         }
 702 }
 703 EXPORT_SYMBOL(ping_evictor_start);
 704
 705 void ping_evictor_stop(void)
 706 {
 707         if (--pet_refcount > 0)
 708                 return;
 709
 710         pet_state = PET_TERMINATE;
 711         wake_up(&pet_waitq);
 712 }
 713 EXPORT_SYMBOL(ping_evictor_stop);