Pileus Git - ~andy/linux/blob - 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 <obd_support.h>
  44 #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 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 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 atomic_t suspend_timeouts = ATOMIC_INIT(0);
 145 static cfs_time_t suspend_wakeup_time = 0;
 146
 147 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         /* The timeout list is a increase order sorted list */
 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 static wait_queue_head_t suspend_timeouts_waitq;
 167
 168 cfs_time_t ptlrpc_suspend_wakeup_time(void)
 169 {
 170         return suspend_wakeup_time;
 171 }
 172
 173 void ptlrpc_deactivate_timeouts(struct obd_import *imp)
 174 {
 175         /*XXX: disabled for now, will be replaced by adaptive timeouts */
 176 #if 0
 177         if (imp->imp_no_timeout)
 178                 return;
 179         imp->imp_no_timeout = 1;
 180         atomic_inc(&suspend_timeouts);
 181         CDEBUG(D_HA|D_WARNING, "deactivate timeouts %u\n",
 182                atomic_read(&suspend_timeouts));
 183 #endif
 184 }
 185
 186 void ptlrpc_activate_timeouts(struct obd_import *imp)
 187 {
 188         /*XXX: disabled for now, will be replaced by adaptive timeouts */
 189 #if 0
 190         if (!imp->imp_no_timeout)
 191                 return;
 192         imp->imp_no_timeout = 0;
 193         LASSERT(atomic_read(&suspend_timeouts) > 0);
 194         if (atomic_dec_and_test(&suspend_timeouts)) {
 195                 suspend_wakeup_time = cfs_time_current();
 196                 wake_up(&suspend_timeouts_waitq);
 197         }
 198         CDEBUG(D_HA|D_WARNING, "activate timeouts %u\n",
 199                atomic_read(&suspend_timeouts));
 200 #endif
 201 }
 202
 203 int ptlrpc_check_suspend(void)
 204 {
 205         if (atomic_read(&suspend_timeouts))
 206                 return 1;
 207         return 0;
 208 }
 209
 210 int ptlrpc_check_and_wait_suspend(struct ptlrpc_request *req)
 211 {
 212         struct l_wait_info lwi;
 213
 214         if (atomic_read(&suspend_timeouts)) {
 215                 DEBUG_REQ(D_NET, req, "-- suspend %d regular timeout",
 216                           atomic_read(&suspend_timeouts));
 217                 lwi = LWI_INTR(NULL, NULL);
 218                 l_wait_event(suspend_timeouts_waitq,
 219                              atomic_read(&suspend_timeouts) == 0, &lwi);
 220                 DEBUG_REQ(D_NET, req, "-- recharge regular timeout");
 221                 return 1;
 222         }
 223         return 0;
 224 }
 225
 226
 227 static bool ir_up;
 228
 229 void ptlrpc_pinger_ir_up(void)
 230 {
 231         CDEBUG(D_HA, "IR up\n");
 232         ir_up = true;
 233 }
 234 EXPORT_SYMBOL(ptlrpc_pinger_ir_up);
 235
 236 void ptlrpc_pinger_ir_down(void)
 237 {
 238         CDEBUG(D_HA, "IR down\n");
 239         ir_up = false;
 240 }
 241 EXPORT_SYMBOL(ptlrpc_pinger_ir_down);
 242
 243 static void ptlrpc_pinger_process_import(struct obd_import *imp,
 244                                          unsigned long this_ping)
 245 {
 246         int level;
 247         int force;
 248         int force_next;
 249         int suppress;
 250
 251         spin_lock(&imp->imp_lock);
 252
 253         level = imp->imp_state;
 254         force = imp->imp_force_verify;
 255         force_next = imp->imp_force_next_verify;
 256         /*
 257          * This will be used below only if the import is "FULL".
 258          */
 259         suppress = ir_up && OCD_HAS_FLAG(&imp->imp_connect_data, PINGLESS);
 260
 261         imp->imp_force_verify = 0;
 262
 263         if (cfs_time_aftereq(imp->imp_next_ping - 5 * CFS_TICK, this_ping) &&
 264             !force) {
 265                 spin_unlock(&imp->imp_lock);
 266                 return;
 267         }
 268
 269         imp->imp_force_next_verify = 0;
 270
 271         spin_unlock(&imp->imp_lock);
 272
 273         CDEBUG(level == LUSTRE_IMP_FULL ? D_INFO : D_HA, "%s->%s: level %s/%u "
 274                "force %u force_next %u deactive %u pingable %u suppress %u\n",
 275                imp->imp_obd->obd_uuid.uuid, obd2cli_tgt(imp->imp_obd),
 276                ptlrpc_import_state_name(level), level, force, force_next,
 277                imp->imp_deactive, imp->imp_pingable, suppress);
 278
 279         if (level == LUSTRE_IMP_DISCON && !imp_is_deactive(imp)) {
 280                 /* wait for a while before trying recovery again */
 281                 imp->imp_next_ping = ptlrpc_next_reconnect(imp);
 282                 if (!imp->imp_no_pinger_recover)
 283                         ptlrpc_initiate_recovery(imp);
 284         } else if (level != LUSTRE_IMP_FULL ||
 285                    imp->imp_obd->obd_no_recov ||
 286                    imp_is_deactive(imp)) {
 287                 CDEBUG(D_HA, "%s->%s: not pinging (in recovery "
 288                        "or recovery disabled: %s)\n",
 289                        imp->imp_obd->obd_uuid.uuid, obd2cli_tgt(imp->imp_obd),
 290                        ptlrpc_import_state_name(level));
 291         } else if ((imp->imp_pingable && !suppress) || force_next || force) {
 292                 ptlrpc_ping(imp);
 293         }
 294 }
 295
 296 static int ptlrpc_pinger_main(void *arg)
 297 {
 298         struct ptlrpc_thread *thread = (struct ptlrpc_thread *)arg;
 299
 300         /* Record that the thread is running */
 301         thread_set_flags(thread, SVC_RUNNING);
 302         wake_up(&thread->t_ctl_waitq);
 303
 304         /* And now, loop forever, pinging as needed. */
 305         while (1) {
 306                 cfs_time_t this_ping = cfs_time_current();
 307                 struct l_wait_info lwi;
 308                 cfs_duration_t time_to_next_wake;
 309                 struct timeout_item *item;
 310                 struct list_head *iter;
 311
 312                 mutex_lock(&pinger_mutex);
 313                 list_for_each_entry(item, &timeout_list, ti_chain) {
 314                         item->ti_cb(item, item->ti_cb_data);
 315                 }
 316                 list_for_each(iter, &pinger_imports) {
 317                         struct obd_import *imp =
 318                                 list_entry(iter, struct obd_import,
 319                                                imp_pinger_chain);
 320
 321                         ptlrpc_pinger_process_import(imp, this_ping);
 322                         /* obd_timeout might have changed */
 323                         if (imp->imp_pingable && imp->imp_next_ping &&
 324                             cfs_time_after(imp->imp_next_ping,
 325                                            cfs_time_add(this_ping,
 326                                                         cfs_time_seconds(PING_INTERVAL))))
 327                                 ptlrpc_update_next_ping(imp, 0);
 328                 }
 329                 mutex_unlock(&pinger_mutex);
 330                 /* update memory usage info */
 331                 obd_update_maxusage();
 332
 333                 /* Wait until the next ping time, or until we're stopped. */
 334                 time_to_next_wake = pinger_check_timeout(this_ping);
 335                 /* The ping sent by ptlrpc_send_rpc may get sent out
 336                    say .01 second after this.
 337                    ptlrpc_pinger_sending_on_import will then set the
 338                    next ping time to next_ping + .01 sec, which means
 339                    we will SKIP the next ping at next_ping, and the
 340                    ping will get sent 2 timeouts from now!  Beware. */
 341                 CDEBUG(D_INFO, "next wakeup in "CFS_DURATION_T" ("
 342                        CFS_TIME_T")\n", time_to_next_wake,
 343                        cfs_time_add(this_ping,cfs_time_seconds(PING_INTERVAL)));
 344                 if (time_to_next_wake > 0) {
 345                         lwi = LWI_TIMEOUT(max_t(cfs_duration_t,
 346                                                 time_to_next_wake,
 347                                                 cfs_time_seconds(1)),
 348                                           NULL, NULL);
 349                         l_wait_event(thread->t_ctl_waitq,
 350                                      thread_is_stopping(thread) ||
 351                                      thread_is_event(thread),
 352                                      &lwi);
 353                         if (thread_test_and_clear_flags(thread, SVC_STOPPING)) {
 354                                 break;
 355                         } else {
 356                                 /* woken after adding import to reset timer */
 357                                 thread_test_and_clear_flags(thread, SVC_EVENT);
 358                         }
 359                 }
 360         }
 361
 362         thread_set_flags(thread, SVC_STOPPED);
 363         wake_up(&thread->t_ctl_waitq);
 364
 365         CDEBUG(D_NET, "pinger thread exiting, process %d\n", current_pid());
 366         return 0;
 367 }
 368
 369 static struct ptlrpc_thread pinger_thread;
 370
 371 int ptlrpc_start_pinger(void)
 372 {
 373         struct l_wait_info lwi = { 0 };
 374         int rc;
 375
 376         if (!thread_is_init(&pinger_thread) &&
 377             !thread_is_stopped(&pinger_thread))
 378                 return -EALREADY;
 379
 380         init_waitqueue_head(&pinger_thread.t_ctl_waitq);
 381         init_waitqueue_head(&suspend_timeouts_waitq);
 382
 383         strcpy(pinger_thread.t_name, "ll_ping");
 384
 385         /* CLONE_VM and CLONE_FILES just avoid a needless copy, because we
 386          * just drop the VM and FILES in cfs_daemonize_ctxt() right away. */
 387         rc = PTR_ERR(kthread_run(ptlrpc_pinger_main, &pinger_thread,
 388                                  "%s", pinger_thread.t_name));
 389         if (IS_ERR_VALUE(rc)) {
 390                 CERROR("cannot start thread: %d\n", rc);
 391                 return rc;
 392         }
 393         l_wait_event(pinger_thread.t_ctl_waitq,
 394                      thread_is_running(&pinger_thread), &lwi);
 395
 396         if (suppress_pings)
 397                 CWARN("Pings will be suppressed at the request of the "
 398                       "administrator.  The configuration shall meet the "
 399                       "additional requirements described in the manual.  "
 400                       "(Search for the \"suppress_pings\" kernel module "
 401                       "parameter.)\n");
 402
 403         return 0;
 404 }
 405
 406 int ptlrpc_pinger_remove_timeouts(void);
 407
 408 int ptlrpc_stop_pinger(void)
 409 {
 410         struct l_wait_info lwi = { 0 };
 411         int rc = 0;
 412
 413         if (thread_is_init(&pinger_thread) ||
 414             thread_is_stopped(&pinger_thread))
 415                 return -EALREADY;
 416
 417         ptlrpc_pinger_remove_timeouts();
 418         thread_set_flags(&pinger_thread, SVC_STOPPING);
 419         wake_up(&pinger_thread.t_ctl_waitq);
 420
 421         l_wait_event(pinger_thread.t_ctl_waitq,
 422                      thread_is_stopped(&pinger_thread), &lwi);
 423
 424         return rc;
 425 }
 426
 427 void ptlrpc_pinger_sending_on_import(struct obd_import *imp)
 428 {
 429         ptlrpc_update_next_ping(imp, 0);
 430 }
 431 EXPORT_SYMBOL(ptlrpc_pinger_sending_on_import);
 432
 433 void ptlrpc_pinger_commit_expected(struct obd_import *imp)
 434 {
 435         ptlrpc_update_next_ping(imp, 1);
 436         LASSERT(spin_is_locked(&imp->imp_lock));
 437         /*
 438          * Avoid reading stale imp_connect_data.  When not sure if pings are
 439          * expected or not on next connection, we assume they are not and force
 440          * one anyway to guarantee the chance of updating
 441          * imp_peer_committed_transno.
 442          */
 443         if (imp->imp_state != LUSTRE_IMP_FULL ||
 444             OCD_HAS_FLAG(&imp->imp_connect_data, PINGLESS))
 445                 imp->imp_force_next_verify = 1;
 446 }
 447
 448 int ptlrpc_pinger_add_import(struct obd_import *imp)
 449 {
 450         if (!list_empty(&imp->imp_pinger_chain))
 451                 return -EALREADY;
 452
 453         mutex_lock(&pinger_mutex);
 454         CDEBUG(D_HA, "adding pingable import %s->%s\n",
 455                imp->imp_obd->obd_uuid.uuid, obd2cli_tgt(imp->imp_obd));
 456         /* if we add to pinger we want recovery on this import */
 457         imp->imp_obd->obd_no_recov = 0;
 458         ptlrpc_update_next_ping(imp, 0);
 459         /* XXX sort, blah blah */
 460         list_add_tail(&imp->imp_pinger_chain, &pinger_imports);
 461         class_import_get(imp);
 462
 463         ptlrpc_pinger_wake_up();
 464         mutex_unlock(&pinger_mutex);
 465
 466         return 0;
 467 }
 468 EXPORT_SYMBOL(ptlrpc_pinger_add_import);
 469
 470 int ptlrpc_pinger_del_import(struct obd_import *imp)
 471 {
 472         if (list_empty(&imp->imp_pinger_chain))
 473                 return -ENOENT;
 474
 475         mutex_lock(&pinger_mutex);
 476         list_del_init(&imp->imp_pinger_chain);
 477         CDEBUG(D_HA, "removing pingable import %s->%s\n",
 478                imp->imp_obd->obd_uuid.uuid, obd2cli_tgt(imp->imp_obd));
 479         /* if we remove from pinger we don't want recovery on this import */
 480         imp->imp_obd->obd_no_recov = 1;
 481         class_import_put(imp);
 482         mutex_unlock(&pinger_mutex);
 483         return 0;
 484 }
 485 EXPORT_SYMBOL(ptlrpc_pinger_del_import);
 486
 487 /**
 488  * Register a timeout callback to the pinger list, and the callback will
 489  * be called when timeout happens.
 490  */
 491 struct timeout_item* ptlrpc_new_timeout(int time, enum timeout_event event,
 492                                         timeout_cb_t cb, void *data)
 493 {
 494         struct timeout_item *ti;
 495
 496         OBD_ALLOC_PTR(ti);
 497         if (!ti)
 498                 return(NULL);
 499
 500         INIT_LIST_HEAD(&ti->ti_obd_list);
 501         INIT_LIST_HEAD(&ti->ti_chain);
 502         ti->ti_timeout = time;
 503         ti->ti_event = event;
 504         ti->ti_cb = cb;
 505         ti->ti_cb_data = data;
 506
 507         return ti;
 508 }
 509
 510 /**
 511  * Register timeout event on the the pinger thread.
 512  * Note: the timeout list is an sorted list with increased timeout value.
 513  */
 514 static struct timeout_item*
 515 ptlrpc_pinger_register_timeout(int time, enum timeout_event event,
 516                                timeout_cb_t cb, void *data)
 517 {
 518         struct timeout_item *item, *tmp;
 519
 520         LASSERT(mutex_is_locked(&pinger_mutex));
 521
 522         list_for_each_entry(item, &timeout_list, ti_chain)
 523                 if (item->ti_event == event)
 524                         goto out;
 525
 526         item = ptlrpc_new_timeout(time, event, cb, data);
 527         if (item) {
 528                 list_for_each_entry_reverse(tmp, &timeout_list, ti_chain) {
 529                         if (tmp->ti_timeout < time) {
 530                                 list_add(&item->ti_chain, &tmp->ti_chain);
 531                                 goto out;
 532                         }
 533                 }
 534                 list_add(&item->ti_chain, &timeout_list);
 535         }
 536 out:
 537         return item;
 538 }
 539
 540 /* Add a client_obd to the timeout event list, when timeout(@time)
 541  * happens, the callback(@cb) will be called.
 542  */
 543 int ptlrpc_add_timeout_client(int time, enum timeout_event event,
 544                               timeout_cb_t cb, void *data,
 545                               struct list_head *obd_list)
 546 {
 547         struct timeout_item *ti;
 548
 549         mutex_lock(&pinger_mutex);
 550         ti = ptlrpc_pinger_register_timeout(time, event, cb, data);
 551         if (!ti) {
 552                 mutex_unlock(&pinger_mutex);
 553                 return (-EINVAL);
 554         }
 555         list_add(obd_list, &ti->ti_obd_list);
 556         mutex_unlock(&pinger_mutex);
 557         return 0;
 558 }
 559 EXPORT_SYMBOL(ptlrpc_add_timeout_client);
 560
 561 int ptlrpc_del_timeout_client(struct list_head *obd_list,
 562                               enum timeout_event event)
 563 {
 564         struct timeout_item *ti = NULL, *item;
 565
 566         if (list_empty(obd_list))
 567                 return 0;
 568         mutex_lock(&pinger_mutex);
 569         list_del_init(obd_list);
 570         /**
 571          * If there are no obd attached to the timeout event
 572          * list, remove this timeout event from the pinger
 573          */
 574         list_for_each_entry(item, &timeout_list, ti_chain) {
 575                 if (item->ti_event == event) {
 576                         ti = item;
 577                         break;
 578                 }
 579         }
 580         LASSERTF(ti != NULL, "ti is NULL !\n");
 581         if (list_empty(&ti->ti_obd_list)) {
 582                 list_del(&ti->ti_chain);
 583                 OBD_FREE_PTR(ti);
 584         }
 585         mutex_unlock(&pinger_mutex);
 586         return 0;
 587 }
 588 EXPORT_SYMBOL(ptlrpc_del_timeout_client);
 589
 590 int ptlrpc_pinger_remove_timeouts(void)
 591 {
 592         struct timeout_item *item, *tmp;
 593
 594         mutex_lock(&pinger_mutex);
 595         list_for_each_entry_safe(item, tmp, &timeout_list, ti_chain) {
 596                 LASSERT(list_empty(&item->ti_obd_list));
 597                 list_del(&item->ti_chain);
 598                 OBD_FREE_PTR(item);
 599         }
 600         mutex_unlock(&pinger_mutex);
 601         return 0;
 602 }
 603
 604 void ptlrpc_pinger_wake_up(void)
 605 {
 606         thread_add_flags(&pinger_thread, SVC_EVENT);
 607         wake_up(&pinger_thread.t_ctl_waitq);
 608 }
 609
 610 /* Ping evictor thread */
 611 #define PET_READY     1
 612 #define PET_TERMINATE 2
 613
 614 static int             pet_refcount = 0;
 615 static int             pet_state;
 616 static wait_queue_head_t       pet_waitq;
 617 LIST_HEAD(pet_list);
 618 static DEFINE_SPINLOCK(pet_lock);
 619
 620 int ping_evictor_wake(struct obd_export *exp)
 621 {
 622         struct obd_device *obd;
 623
 624         spin_lock(&pet_lock);
 625         if (pet_state != PET_READY) {
 626                 /* eventually the new obd will call here again. */
 627                 spin_unlock(&pet_lock);
 628                 return 1;
 629         }
 630
 631         obd = class_exp2obd(exp);
 632         if (list_empty(&obd->obd_evict_list)) {
 633                 class_incref(obd, "evictor", obd);
 634                 list_add(&obd->obd_evict_list, &pet_list);
 635         }
 636         spin_unlock(&pet_lock);
 637
 638         wake_up(&pet_waitq);
 639         return 0;
 640 }
 641
 642 static int ping_evictor_main(void *arg)
 643 {
 644         struct obd_device *obd;
 645         struct obd_export *exp;
 646         struct l_wait_info lwi = { 0 };
 647         time_t expire_time;
 648
 649         unshare_fs_struct();
 650
 651         CDEBUG(D_HA, "Starting Ping Evictor\n");
 652         pet_state = PET_READY;
 653         while (1) {
 654                 l_wait_event(pet_waitq, (!list_empty(&pet_list)) ||
 655                              (pet_state == PET_TERMINATE), &lwi);
 656
 657                 /* loop until all obd's will be removed */
 658                 if ((pet_state == PET_TERMINATE) && list_empty(&pet_list))
 659                         break;
 660
 661                 /* we only get here if pet_exp != NULL, and the end of this
 662                  * loop is the only place which sets it NULL again, so lock
 663                  * is not strictly necessary. */
 664                 spin_lock(&pet_lock);
 665                 obd = list_entry(pet_list.next, struct obd_device,
 666                                      obd_evict_list);
 667                 spin_unlock(&pet_lock);
 668
 669                 expire_time = cfs_time_current_sec() - PING_EVICT_TIMEOUT;
 670
 671                 CDEBUG(D_HA, "evicting all exports of obd %s older than %ld\n",
 672                        obd->obd_name, expire_time);
 673
 674                 /* Exports can't be deleted out of the list while we hold
 675                  * the obd lock (class_unlink_export), which means we can't
 676                  * lose the last ref on the export.  If they've already been
 677                  * removed from the list, we won't find them here. */
 678                 spin_lock(&obd->obd_dev_lock);
 679                 while (!list_empty(&obd->obd_exports_timed)) {
 680                         exp = list_entry(obd->obd_exports_timed.next,
 681                                              struct obd_export,
 682                                              exp_obd_chain_timed);
 683                         if (expire_time > exp->exp_last_request_time) {
 684                                 class_export_get(exp);
 685                                 spin_unlock(&obd->obd_dev_lock);
 686                                 LCONSOLE_WARN("%s: haven't heard from client %s"
 687                                               " (at %s) in %ld seconds. I think"
 688                                               " it's dead, and I am evicting"
 689                                               " it. exp %p, cur %ld expire %ld"
 690                                               " last %ld\n",
 691                                               obd->obd_name,
 692                                               obd_uuid2str(&exp->exp_client_uuid),
 693                                               obd_export_nid2str(exp),
 694                                               (long)(cfs_time_current_sec() -
 695                                                      exp->exp_last_request_time),
 696                                               exp, (long)cfs_time_current_sec(),
 697                                               (long)expire_time,
 698                                               (long)exp->exp_last_request_time);
 699                                 CDEBUG(D_HA, "Last request was at %ld\n",
 700                                        exp->exp_last_request_time);
 701                                 class_fail_export(exp);
 702                                 class_export_put(exp);
 703                                 spin_lock(&obd->obd_dev_lock);
 704                         } else {
 705                                 /* List is sorted, so everyone below is ok */
 706                                 break;
 707                         }
 708                 }
 709                 spin_unlock(&obd->obd_dev_lock);
 710
 711                 spin_lock(&pet_lock);
 712                 list_del_init(&obd->obd_evict_list);
 713                 spin_unlock(&pet_lock);
 714
 715                 class_decref(obd, "evictor", obd);
 716         }
 717         CDEBUG(D_HA, "Exiting Ping Evictor\n");
 718
 719         return 0;
 720 }
 721
 722 void ping_evictor_start(void)
 723 {
 724         struct task_struct *task;
 725
 726         if (++pet_refcount > 1)
 727                 return;
 728
 729         init_waitqueue_head(&pet_waitq);
 730
 731         task = kthread_run(ping_evictor_main, NULL, "ll_evictor");
 732         if (IS_ERR(task)) {
 733                 pet_refcount--;
 734                 CERROR("Cannot start ping evictor thread: %ld\n",
 735                         PTR_ERR(task));
 736         }
 737 }
 738 EXPORT_SYMBOL(ping_evictor_start);
 739
 740 void ping_evictor_stop(void)
 741 {
 742         if (--pet_refcount > 0)
 743                 return;
 744
 745         pet_state = PET_TERMINATE;
 746         wake_up(&pet_waitq);
 747 }
 748 EXPORT_SYMBOL(ping_evictor_stop);