kernel/drivers/staging/lustre/lustre/ldlm/ldlm_lockd.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) 2002, 2010, Oracle and/or its affiliates. All rights reserved.
  28  * Use is subject to license terms.
  29  *
  30  * Copyright (c) 2010, 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/ldlm/ldlm_lockd.c
  37  *
  38  * Author: Peter Braam <braam@clusterfs.com>
  39  * Author: Phil Schwan <phil@clusterfs.com>
  40  */
  41
  42 #define DEBUG_SUBSYSTEM S_LDLM
  43
  44 #include "../../include/linux/libcfs/libcfs.h"
  45 #include "../include/lustre_dlm.h"
  46 #include "../include/obd_class.h"
  47 #include <linux/list.h>
  48 #include "ldlm_internal.h"
  49
  50 static int ldlm_num_threads;
  51 module_param(ldlm_num_threads, int, 0444);
  52 MODULE_PARM_DESC(ldlm_num_threads, "number of DLM service threads to start");
  53
  54 static char *ldlm_cpts;
  55 module_param(ldlm_cpts, charp, 0444);
  56 MODULE_PARM_DESC(ldlm_cpts, "CPU partitions ldlm threads should run on");
  57
  58 static struct mutex     ldlm_ref_mutex;
  59 static int ldlm_refcount;
  60
  61 struct ldlm_cb_async_args {
  62         struct ldlm_cb_set_arg *ca_set_arg;
  63         struct ldlm_lock       *ca_lock;
  64 };
  65
  66 /* LDLM state */
  67
  68 static struct ldlm_state *ldlm_state;
  69
  70 inline unsigned long round_timeout(unsigned long timeout)
  71 {
  72         return cfs_time_seconds((int)cfs_duration_sec(cfs_time_sub(timeout, 0)) + 1);
  73 }
  74
  75 /* timeout for initial callback (AST) reply (bz10399) */
  76 static inline unsigned int ldlm_get_rq_timeout(void)
  77 {
  78         /* Non-AT value */
  79         unsigned int timeout = min(ldlm_timeout, obd_timeout / 3);
  80
  81         return timeout < 1 ? 1 : timeout;
  82 }
  83
  84 #define ELT_STOPPED   0
  85 #define ELT_READY     1
  86 #define ELT_TERMINATE 2
  87
  88 struct ldlm_bl_pool {
  89         spinlock_t              blp_lock;
  90
  91         /*
  92          * blp_prio_list is used for callbacks that should be handled
  93          * as a priority. It is used for LDLM_FL_DISCARD_DATA requests.
  94          * see bug 13843
  95          */
  96         struct list_head              blp_prio_list;
  97
  98         /*
  99          * blp_list is used for all other callbacks which are likely
 100          * to take longer to process.
 101          */
 102         struct list_head              blp_list;
 103
 104         wait_queue_head_t            blp_waitq;
 105         struct completion       blp_comp;
 106         atomic_t            blp_num_threads;
 107         atomic_t            blp_busy_threads;
 108         int                  blp_min_threads;
 109         int                  blp_max_threads;
 110 };
 111
 112 struct ldlm_bl_work_item {
 113         struct list_head              blwi_entry;
 114         struct ldlm_namespace  *blwi_ns;
 115         struct ldlm_lock_desc   blwi_ld;
 116         struct ldlm_lock       *blwi_lock;
 117         struct list_head              blwi_head;
 118         int                  blwi_count;
 119         struct completion       blwi_comp;
 120         ldlm_cancel_flags_t     blwi_flags;
 121         int                  blwi_mem_pressure;
 122 };
 123
 124
 125 int ldlm_del_waiting_lock(struct ldlm_lock *lock)
 126 {
 127         return 0;
 128 }
 129
 130 int ldlm_refresh_waiting_lock(struct ldlm_lock *lock, int timeout)
 131 {
 132         return 0;
 133 }
 134
 135
 136
 137 /**
 138  * Callback handler for receiving incoming blocking ASTs.
 139  *
 140  * This can only happen on client side.
 141  */
 142 void ldlm_handle_bl_callback(struct ldlm_namespace *ns,
 143                              struct ldlm_lock_desc *ld, struct ldlm_lock *lock)
 144 {
 145         int do_ast;
 146
 147         LDLM_DEBUG(lock, "client blocking AST callback handler");
 148
 149         lock_res_and_lock(lock);
 150         lock->l_flags |= LDLM_FL_CBPENDING;
 151
 152         if (lock->l_flags & LDLM_FL_CANCEL_ON_BLOCK)
 153                 lock->l_flags |= LDLM_FL_CANCEL;
 154
 155         do_ast = !lock->l_readers && !lock->l_writers;
 156         unlock_res_and_lock(lock);
 157
 158         if (do_ast) {
 159                 CDEBUG(D_DLMTRACE,
 160                        "Lock %p already unused, calling callback (%p)\n", lock,
 161                        lock->l_blocking_ast);
 162                 if (lock->l_blocking_ast != NULL)
 163                         lock->l_blocking_ast(lock, ld, lock->l_ast_data,
 164                                              LDLM_CB_BLOCKING);
 165         } else {
 166                 CDEBUG(D_DLMTRACE,
 167                        "Lock %p is referenced, will be cancelled later\n",
 168                        lock);
 169         }
 170
 171         LDLM_DEBUG(lock, "client blocking callback handler END");
 172         LDLM_LOCK_RELEASE(lock);
 173 }
 174
 175 /**
 176  * Callback handler for receiving incoming completion ASTs.
 177  *
 178  * This only can happen on client side.
 179  */
 180 static void ldlm_handle_cp_callback(struct ptlrpc_request *req,
 181                                     struct ldlm_namespace *ns,
 182                                     struct ldlm_request *dlm_req,
 183                                     struct ldlm_lock *lock)
 184 {
 185         int lvb_len;
 186         LIST_HEAD(ast_list);
 187         int rc = 0;
 188
 189         LDLM_DEBUG(lock, "client completion callback handler START");
 190
 191         if (OBD_FAIL_CHECK(OBD_FAIL_LDLM_CANCEL_BL_CB_RACE)) {
 192                 int to = cfs_time_seconds(1);
 193
 194                 while (to > 0) {
 195                         set_current_state(TASK_INTERRUPTIBLE);
 196                         schedule_timeout(to);
 197                         if (lock->l_granted_mode == lock->l_req_mode ||
 198                             lock->l_flags & LDLM_FL_DESTROYED)
 199                                 break;
 200                 }
 201         }
 202
 203         lvb_len = req_capsule_get_size(&req->rq_pill, &RMF_DLM_LVB, RCL_CLIENT);
 204         if (lvb_len < 0) {
 205                 LDLM_ERROR(lock, "Fail to get lvb_len, rc = %d", lvb_len);
 206                 rc = lvb_len;
 207                 goto out;
 208         } else if (lvb_len > 0) {
 209                 if (lock->l_lvb_len > 0) {
 210                         /* for extent lock, lvb contains ost_lvb{}. */
 211                         LASSERT(lock->l_lvb_data != NULL);
 212
 213                         if (unlikely(lock->l_lvb_len < lvb_len)) {
 214                                 LDLM_ERROR(lock, "Replied LVB is larger than expectation, expected = %d, replied = %d",
 215                                            lock->l_lvb_len, lvb_len);
 216                                 rc = -EINVAL;
 217                                 goto out;
 218                         }
 219                 } else if (ldlm_has_layout(lock)) { /* for layout lock, lvb has
 220                                                      * variable length */
 221                         void *lvb_data;
 222
 223                         OBD_ALLOC(lvb_data, lvb_len);
 224                         if (lvb_data == NULL) {
 225                                 LDLM_ERROR(lock, "No memory: %d.\n", lvb_len);
 226                                 rc = -ENOMEM;
 227                                 goto out;
 228                         }
 229
 230                         lock_res_and_lock(lock);
 231                         LASSERT(lock->l_lvb_data == NULL);
 232                         lock->l_lvb_type = LVB_T_LAYOUT;
 233                         lock->l_lvb_data = lvb_data;
 234                         lock->l_lvb_len = lvb_len;
 235                         unlock_res_and_lock(lock);
 236                 }
 237         }
 238
 239         lock_res_and_lock(lock);
 240         if ((lock->l_flags & LDLM_FL_DESTROYED) ||
 241             lock->l_granted_mode == lock->l_req_mode) {
 242                 /* bug 11300: the lock has already been granted */
 243                 unlock_res_and_lock(lock);
 244                 LDLM_DEBUG(lock, "Double grant race happened");
 245                 rc = 0;
 246                 goto out;
 247         }
 248
 249         /* If we receive the completion AST before the actual enqueue returned,
 250          * then we might need to switch lock modes, resources, or extents. */
 251         if (dlm_req->lock_desc.l_granted_mode != lock->l_req_mode) {
 252                 lock->l_req_mode = dlm_req->lock_desc.l_granted_mode;
 253                 LDLM_DEBUG(lock, "completion AST, new lock mode");
 254         }
 255
 256         if (lock->l_resource->lr_type != LDLM_PLAIN) {
 257                 ldlm_convert_policy_to_local(req->rq_export,
 258                                           dlm_req->lock_desc.l_resource.lr_type,
 259                                           &dlm_req->lock_desc.l_policy_data,
 260                                           &lock->l_policy_data);
 261                 LDLM_DEBUG(lock, "completion AST, new policy data");
 262         }
 263
 264         ldlm_resource_unlink_lock(lock);
 265         if (memcmp(&dlm_req->lock_desc.l_resource.lr_name,
 266                    &lock->l_resource->lr_name,
 267                    sizeof(lock->l_resource->lr_name)) != 0) {
 268                 unlock_res_and_lock(lock);
 269                 rc = ldlm_lock_change_resource(ns, lock,
 270                                 &dlm_req->lock_desc.l_resource.lr_name);
 271                 if (rc < 0) {
 272                         LDLM_ERROR(lock, "Failed to allocate resource");
 273                         goto out;
 274                 }
 275                 LDLM_DEBUG(lock, "completion AST, new resource");
 276                 CERROR("change resource!\n");
 277                 lock_res_and_lock(lock);
 278         }
 279
 280         if (dlm_req->lock_flags & LDLM_FL_AST_SENT) {
 281                 /* BL_AST locks are not needed in LRU.
 282                  * Let ldlm_cancel_lru() be fast. */
 283                 ldlm_lock_remove_from_lru(lock);
 284                 lock->l_flags |= LDLM_FL_CBPENDING | LDLM_FL_BL_AST;
 285                 LDLM_DEBUG(lock, "completion AST includes blocking AST");
 286         }
 287
 288         if (lock->l_lvb_len > 0) {
 289                 rc = ldlm_fill_lvb(lock, &req->rq_pill, RCL_CLIENT,
 290                                    lock->l_lvb_data, lvb_len);
 291                 if (rc < 0) {
 292                         unlock_res_and_lock(lock);
 293                         goto out;
 294                 }
 295         }
 296
 297         ldlm_grant_lock(lock, &ast_list);
 298         unlock_res_and_lock(lock);
 299
 300         LDLM_DEBUG(lock, "callback handler finished, about to run_ast_work");
 301
 302         /* Let Enqueue to call osc_lock_upcall() and initialize
 303          * l_ast_data */
 304         OBD_FAIL_TIMEOUT(OBD_FAIL_OSC_CP_ENQ_RACE, 2);
 305
 306         ldlm_run_ast_work(ns, &ast_list, LDLM_WORK_CP_AST);
 307
 308         LDLM_DEBUG_NOLOCK("client completion callback handler END (lock %p)",
 309                           lock);
 310         goto out;
 311
 312 out:
 313         if (rc < 0) {
 314                 lock_res_and_lock(lock);
 315                 lock->l_flags |= LDLM_FL_FAILED;
 316                 unlock_res_and_lock(lock);
 317                 wake_up(&lock->l_waitq);
 318         }
 319         LDLM_LOCK_RELEASE(lock);
 320 }
 321
 322 /**
 323  * Callback handler for receiving incoming glimpse ASTs.
 324  *
 325  * This only can happen on client side.  After handling the glimpse AST
 326  * we also consider dropping the lock here if it is unused locally for a
 327  * long time.
 328  */
 329 static void ldlm_handle_gl_callback(struct ptlrpc_request *req,
 330                                     struct ldlm_namespace *ns,
 331                                     struct ldlm_request *dlm_req,
 332                                     struct ldlm_lock *lock)
 333 {
 334         int rc = -ENOSYS;
 335
 336         LDLM_DEBUG(lock, "client glimpse AST callback handler");
 337
 338         if (lock->l_glimpse_ast != NULL)
 339                 rc = lock->l_glimpse_ast(lock, req);
 340
 341         if (req->rq_repmsg != NULL) {
 342                 ptlrpc_reply(req);
 343         } else {
 344                 req->rq_status = rc;
 345                 ptlrpc_error(req);
 346         }
 347
 348         lock_res_and_lock(lock);
 349         if (lock->l_granted_mode == LCK_PW &&
 350             !lock->l_readers && !lock->l_writers &&
 351             cfs_time_after(cfs_time_current(),
 352                            cfs_time_add(lock->l_last_used,
 353                                         cfs_time_seconds(10)))) {
 354                 unlock_res_and_lock(lock);
 355                 if (ldlm_bl_to_thread_lock(ns, NULL, lock))
 356                         ldlm_handle_bl_callback(ns, NULL, lock);
 357
 358                 return;
 359         }
 360         unlock_res_and_lock(lock);
 361         LDLM_LOCK_RELEASE(lock);
 362 }
 363
 364 static int ldlm_callback_reply(struct ptlrpc_request *req, int rc)
 365 {
 366         if (req->rq_no_reply)
 367                 return 0;
 368
 369         req->rq_status = rc;
 370         if (!req->rq_packed_final) {
 371                 rc = lustre_pack_reply(req, 1, NULL, NULL);
 372                 if (rc)
 373                         return rc;
 374         }
 375         return ptlrpc_reply(req);
 376 }
 377
 378 static int __ldlm_bl_to_thread(struct ldlm_bl_work_item *blwi,
 379                                ldlm_cancel_flags_t cancel_flags)
 380 {
 381         struct ldlm_bl_pool *blp = ldlm_state->ldlm_bl_pool;
 382
 383         spin_lock(&blp->blp_lock);
 384         if (blwi->blwi_lock &&
 385             blwi->blwi_lock->l_flags & LDLM_FL_DISCARD_DATA) {
 386                 /* add LDLM_FL_DISCARD_DATA requests to the priority list */
 387                 list_add_tail(&blwi->blwi_entry, &blp->blp_prio_list);
 388         } else {
 389                 /* other blocking callbacks are added to the regular list */
 390                 list_add_tail(&blwi->blwi_entry, &blp->blp_list);
 391         }
 392         spin_unlock(&blp->blp_lock);
 393
 394         wake_up(&blp->blp_waitq);
 395
 396         /* can not check blwi->blwi_flags as blwi could be already freed in
 397            LCF_ASYNC mode */
 398         if (!(cancel_flags & LCF_ASYNC))
 399                 wait_for_completion(&blwi->blwi_comp);
 400
 401         return 0;
 402 }
 403
 404 static inline void init_blwi(struct ldlm_bl_work_item *blwi,
 405                              struct ldlm_namespace *ns,
 406                              struct ldlm_lock_desc *ld,
 407                              struct list_head *cancels, int count,
 408                              struct ldlm_lock *lock,
 409                              ldlm_cancel_flags_t cancel_flags)
 410 {
 411         init_completion(&blwi->blwi_comp);
 412         INIT_LIST_HEAD(&blwi->blwi_head);
 413
 414         if (memory_pressure_get())
 415                 blwi->blwi_mem_pressure = 1;
 416
 417         blwi->blwi_ns = ns;
 418         blwi->blwi_flags = cancel_flags;
 419         if (ld != NULL)
 420                 blwi->blwi_ld = *ld;
 421         if (count) {
 422                 list_add(&blwi->blwi_head, cancels);
 423                 list_del_init(cancels);
 424                 blwi->blwi_count = count;
 425         } else {
 426                 blwi->blwi_lock = lock;
 427         }
 428 }
 429
 430 /**
 431  * Queues a list of locks \a cancels containing \a count locks
 432  * for later processing by a blocking thread.  If \a count is zero,
 433  * then the lock referenced as \a lock is queued instead.
 434  *
 435  * The blocking thread would then call ->l_blocking_ast callback in the lock.
 436  * If list addition fails an error is returned and caller is supposed to
 437  * call ->l_blocking_ast itself.
 438  */
 439 static int ldlm_bl_to_thread(struct ldlm_namespace *ns,
 440                              struct ldlm_lock_desc *ld,
 441                              struct ldlm_lock *lock,
 442                              struct list_head *cancels, int count,
 443                              ldlm_cancel_flags_t cancel_flags)
 444 {
 445         if (cancels && count == 0)
 446                 return 0;
 447
 448         if (cancel_flags & LCF_ASYNC) {
 449                 struct ldlm_bl_work_item *blwi;
 450
 451                 OBD_ALLOC(blwi, sizeof(*blwi));
 452                 if (blwi == NULL)
 453                         return -ENOMEM;
 454                 init_blwi(blwi, ns, ld, cancels, count, lock, cancel_flags);
 455
 456                 return __ldlm_bl_to_thread(blwi, cancel_flags);
 457         } else {
 458                 /* if it is synchronous call do minimum mem alloc, as it could
 459                  * be triggered from kernel shrinker
 460                  */
 461                 struct ldlm_bl_work_item blwi;
 462
 463                 memset(&blwi, 0, sizeof(blwi));
 464                 init_blwi(&blwi, ns, ld, cancels, count, lock, cancel_flags);
 465                 return __ldlm_bl_to_thread(&blwi, cancel_flags);
 466         }
 467 }
 468
 469
 470 int ldlm_bl_to_thread_lock(struct ldlm_namespace *ns, struct ldlm_lock_desc *ld,
 471                            struct ldlm_lock *lock)
 472 {
 473         return ldlm_bl_to_thread(ns, ld, lock, NULL, 0, LCF_ASYNC);
 474 }
 475
 476 int ldlm_bl_to_thread_list(struct ldlm_namespace *ns, struct ldlm_lock_desc *ld,
 477                            struct list_head *cancels, int count,
 478                            ldlm_cancel_flags_t cancel_flags)
 479 {
 480         return ldlm_bl_to_thread(ns, ld, NULL, cancels, count, cancel_flags);
 481 }
 482
 483 /* Setinfo coming from Server (eg MDT) to Client (eg MDC)! */
 484 static int ldlm_handle_setinfo(struct ptlrpc_request *req)
 485 {
 486         struct obd_device *obd = req->rq_export->exp_obd;
 487         char *key;
 488         void *val;
 489         int keylen, vallen;
 490         int rc = -ENOSYS;
 491
 492         DEBUG_REQ(D_HSM, req, "%s: handle setinfo\n", obd->obd_name);
 493
 494         req_capsule_set(&req->rq_pill, &RQF_OBD_SET_INFO);
 495
 496         key = req_capsule_client_get(&req->rq_pill, &RMF_SETINFO_KEY);
 497         if (key == NULL) {
 498                 DEBUG_REQ(D_IOCTL, req, "no set_info key");
 499                 return -EFAULT;
 500         }
 501         keylen = req_capsule_get_size(&req->rq_pill, &RMF_SETINFO_KEY,
 502                                       RCL_CLIENT);
 503         val = req_capsule_client_get(&req->rq_pill, &RMF_SETINFO_VAL);
 504         if (val == NULL) {
 505                 DEBUG_REQ(D_IOCTL, req, "no set_info val");
 506                 return -EFAULT;
 507         }
 508         vallen = req_capsule_get_size(&req->rq_pill, &RMF_SETINFO_VAL,
 509                                       RCL_CLIENT);
 510
 511         /* We are responsible for swabbing contents of val */
 512
 513         if (KEY_IS(KEY_HSM_COPYTOOL_SEND))
 514                 /* Pass it on to mdc (the "export" in this case) */
 515                 rc = obd_set_info_async(req->rq_svc_thread->t_env,
 516                                         req->rq_export,
 517                                         sizeof(KEY_HSM_COPYTOOL_SEND),
 518                                         KEY_HSM_COPYTOOL_SEND,
 519                                         vallen, val, NULL);
 520         else
 521                 DEBUG_REQ(D_WARNING, req, "ignoring unknown key %s", key);
 522
 523         return rc;
 524 }
 525
 526 static inline void ldlm_callback_errmsg(struct ptlrpc_request *req,
 527                                         const char *msg, int rc,
 528                                         struct lustre_handle *handle)
 529 {
 530         DEBUG_REQ((req->rq_no_reply || rc) ? D_WARNING : D_DLMTRACE, req,
 531                   "%s: [nid %s] [rc %d] [lock %#llx]",
 532                   msg, libcfs_id2str(req->rq_peer), rc,
 533                   handle ? handle->cookie : 0);
 534         if (req->rq_no_reply)
 535                 CWARN("No reply was sent, maybe cause bug 21636.\n");
 536         else if (rc)
 537                 CWARN("Send reply failed, maybe cause bug 21636.\n");
 538 }
 539
 540 static int ldlm_handle_qc_callback(struct ptlrpc_request *req)
 541 {
 542         struct obd_quotactl *oqctl;
 543         struct client_obd *cli = &req->rq_export->exp_obd->u.cli;
 544
 545         oqctl = req_capsule_client_get(&req->rq_pill, &RMF_OBD_QUOTACTL);
 546         if (oqctl == NULL) {
 547                 CERROR("Can't unpack obd_quotactl\n");
 548                 return -EPROTO;
 549         }
 550
 551         oqctl->qc_stat = ptlrpc_status_ntoh(oqctl->qc_stat);
 552
 553         cli->cl_qchk_stat = oqctl->qc_stat;
 554         return 0;
 555 }
 556
 557 /* TODO: handle requests in a similar way as MDT: see mdt_handle_common() */
 558 static int ldlm_callback_handler(struct ptlrpc_request *req)
 559 {
 560         struct ldlm_namespace *ns;
 561         struct ldlm_request *dlm_req;
 562         struct ldlm_lock *lock;
 563         int rc;
 564
 565         /* Requests arrive in sender's byte order.  The ptlrpc service
 566          * handler has already checked and, if necessary, byte-swapped the
 567          * incoming request message body, but I am responsible for the
 568          * message buffers. */
 569
 570         /* do nothing for sec context finalize */
 571         if (lustre_msg_get_opc(req->rq_reqmsg) == SEC_CTX_FINI)
 572                 return 0;
 573
 574         req_capsule_init(&req->rq_pill, req, RCL_SERVER);
 575
 576         if (req->rq_export == NULL) {
 577                 rc = ldlm_callback_reply(req, -ENOTCONN);
 578                 ldlm_callback_errmsg(req, "Operate on unconnected server",
 579                                      rc, NULL);
 580                 return 0;
 581         }
 582
 583         LASSERT(req->rq_export != NULL);
 584         LASSERT(req->rq_export->exp_obd != NULL);
 585
 586         switch (lustre_msg_get_opc(req->rq_reqmsg)) {
 587         case LDLM_BL_CALLBACK:
 588                 if (OBD_FAIL_CHECK(OBD_FAIL_LDLM_BL_CALLBACK_NET))
 589                         return 0;
 590                 break;
 591         case LDLM_CP_CALLBACK:
 592                 if (OBD_FAIL_CHECK(OBD_FAIL_LDLM_CP_CALLBACK_NET))
 593                         return 0;
 594                 break;
 595         case LDLM_GL_CALLBACK:
 596                 if (OBD_FAIL_CHECK(OBD_FAIL_LDLM_GL_CALLBACK_NET))
 597                         return 0;
 598                 break;
 599         case LDLM_SET_INFO:
 600                 rc = ldlm_handle_setinfo(req);
 601                 ldlm_callback_reply(req, rc);
 602                 return 0;
 603         case OBD_QC_CALLBACK:
 604                 req_capsule_set(&req->rq_pill, &RQF_QC_CALLBACK);
 605                 if (OBD_FAIL_CHECK(OBD_FAIL_OBD_QC_CALLBACK_NET))
 606                         return 0;
 607                 rc = ldlm_handle_qc_callback(req);
 608                 ldlm_callback_reply(req, rc);
 609                 return 0;
 610         default:
 611                 CERROR("unknown opcode %u\n",
 612                        lustre_msg_get_opc(req->rq_reqmsg));
 613                 ldlm_callback_reply(req, -EPROTO);
 614                 return 0;
 615         }
 616
 617         ns = req->rq_export->exp_obd->obd_namespace;
 618         LASSERT(ns != NULL);
 619
 620         req_capsule_set(&req->rq_pill, &RQF_LDLM_CALLBACK);
 621
 622         dlm_req = req_capsule_client_get(&req->rq_pill, &RMF_DLM_REQ);
 623         if (dlm_req == NULL) {
 624                 rc = ldlm_callback_reply(req, -EPROTO);
 625                 ldlm_callback_errmsg(req, "Operate without parameter", rc,
 626                                      NULL);
 627                 return 0;
 628         }
 629
 630         /* Force a known safe race, send a cancel to the server for a lock
 631          * which the server has already started a blocking callback on. */
 632         if (OBD_FAIL_CHECK(OBD_FAIL_LDLM_CANCEL_BL_CB_RACE) &&
 633             lustre_msg_get_opc(req->rq_reqmsg) == LDLM_BL_CALLBACK) {
 634                 rc = ldlm_cli_cancel(&dlm_req->lock_handle[0], 0);
 635                 if (rc < 0)
 636                         CERROR("ldlm_cli_cancel: %d\n", rc);
 637         }
 638
 639         lock = ldlm_handle2lock_long(&dlm_req->lock_handle[0], 0);
 640         if (!lock) {
 641                 CDEBUG(D_DLMTRACE, "callback on lock %#llx - lock disappeared\n",
 642                        dlm_req->lock_handle[0].cookie);
 643                 rc = ldlm_callback_reply(req, -EINVAL);
 644                 ldlm_callback_errmsg(req, "Operate with invalid parameter", rc,
 645                                      &dlm_req->lock_handle[0]);
 646                 return 0;
 647         }
 648
 649         if ((lock->l_flags & LDLM_FL_FAIL_LOC) &&
 650             lustre_msg_get_opc(req->rq_reqmsg) == LDLM_BL_CALLBACK)
 651                 OBD_RACE(OBD_FAIL_LDLM_CP_BL_RACE);
 652
 653         /* Copy hints/flags (e.g. LDLM_FL_DISCARD_DATA) from AST. */
 654         lock_res_and_lock(lock);
 655         lock->l_flags |= ldlm_flags_from_wire(dlm_req->lock_flags &
 656                                               LDLM_AST_FLAGS);
 657         if (lustre_msg_get_opc(req->rq_reqmsg) == LDLM_BL_CALLBACK) {
 658                 /* If somebody cancels lock and cache is already dropped,
 659                  * or lock is failed before cp_ast received on client,
 660                  * we can tell the server we have no lock. Otherwise, we
 661                  * should send cancel after dropping the cache. */
 662                 if (((lock->l_flags & LDLM_FL_CANCELING) &&
 663                     (lock->l_flags & LDLM_FL_BL_DONE)) ||
 664                     (lock->l_flags & LDLM_FL_FAILED)) {
 665                         LDLM_DEBUG(lock, "callback on lock %#llx - lock disappeared\n",
 666                                    dlm_req->lock_handle[0].cookie);
 667                         unlock_res_and_lock(lock);
 668                         LDLM_LOCK_RELEASE(lock);
 669                         rc = ldlm_callback_reply(req, -EINVAL);
 670                         ldlm_callback_errmsg(req, "Operate on stale lock", rc,
 671                                              &dlm_req->lock_handle[0]);
 672                         return 0;
 673                 }
 674                 /* BL_AST locks are not needed in LRU.
 675                  * Let ldlm_cancel_lru() be fast. */
 676                 ldlm_lock_remove_from_lru(lock);
 677                 lock->l_flags |= LDLM_FL_BL_AST;
 678         }
 679         unlock_res_and_lock(lock);
 680
 681         /* We want the ost thread to get this reply so that it can respond
 682          * to ost requests (write cache writeback) that might be triggered
 683          * in the callback.
 684          *
 685          * But we'd also like to be able to indicate in the reply that we're
 686          * cancelling right now, because it's unused, or have an intent result
 687          * in the reply, so we might have to push the responsibility for sending
 688          * the reply down into the AST handlers, alas. */
 689
 690         switch (lustre_msg_get_opc(req->rq_reqmsg)) {
 691         case LDLM_BL_CALLBACK:
 692                 CDEBUG(D_INODE, "blocking ast\n");
 693                 req_capsule_extend(&req->rq_pill, &RQF_LDLM_BL_CALLBACK);
 694                 if (!(lock->l_flags & LDLM_FL_CANCEL_ON_BLOCK)) {
 695                         rc = ldlm_callback_reply(req, 0);
 696                         if (req->rq_no_reply || rc)
 697                                 ldlm_callback_errmsg(req, "Normal process", rc,
 698                                                      &dlm_req->lock_handle[0]);
 699                 }
 700                 if (ldlm_bl_to_thread_lock(ns, &dlm_req->lock_desc, lock))
 701                         ldlm_handle_bl_callback(ns, &dlm_req->lock_desc, lock);
 702                 break;
 703         case LDLM_CP_CALLBACK:
 704                 CDEBUG(D_INODE, "completion ast\n");
 705                 req_capsule_extend(&req->rq_pill, &RQF_LDLM_CP_CALLBACK);
 706                 ldlm_callback_reply(req, 0);
 707                 ldlm_handle_cp_callback(req, ns, dlm_req, lock);
 708                 break;
 709         case LDLM_GL_CALLBACK:
 710                 CDEBUG(D_INODE, "glimpse ast\n");
 711                 req_capsule_extend(&req->rq_pill, &RQF_LDLM_GL_CALLBACK);
 712                 ldlm_handle_gl_callback(req, ns, dlm_req, lock);
 713                 break;
 714         default:
 715                 LBUG();                  /* checked above */
 716         }
 717
 718         return 0;
 719 }
 720
 721
 722 static struct ldlm_bl_work_item *ldlm_bl_get_work(struct ldlm_bl_pool *blp)
 723 {
 724         struct ldlm_bl_work_item *blwi = NULL;
 725         static unsigned int num_bl;
 726
 727         spin_lock(&blp->blp_lock);
 728         /* process a request from the blp_list at least every blp_num_threads */
 729         if (!list_empty(&blp->blp_list) &&
 730             (list_empty(&blp->blp_prio_list) || num_bl == 0))
 731                 blwi = list_entry(blp->blp_list.next,
 732                                       struct ldlm_bl_work_item, blwi_entry);
 733         else
 734                 if (!list_empty(&blp->blp_prio_list))
 735                         blwi = list_entry(blp->blp_prio_list.next,
 736                                               struct ldlm_bl_work_item,
 737                                               blwi_entry);
 738
 739         if (blwi) {
 740                 if (++num_bl >= atomic_read(&blp->blp_num_threads))
 741                         num_bl = 0;
 742                 list_del(&blwi->blwi_entry);
 743         }
 744         spin_unlock(&blp->blp_lock);
 745
 746         return blwi;
 747 }
 748
 749 /* This only contains temporary data until the thread starts */
 750 struct ldlm_bl_thread_data {
 751         char                    bltd_name[CFS_CURPROC_COMM_MAX];
 752         struct ldlm_bl_pool     *bltd_blp;
 753         struct completion       bltd_comp;
 754         int                     bltd_num;
 755 };
 756
 757 static int ldlm_bl_thread_main(void *arg);
 758
 759 static int ldlm_bl_thread_start(struct ldlm_bl_pool *blp)
 760 {
 761         struct ldlm_bl_thread_data bltd = { .bltd_blp = blp };
 762         struct task_struct *task;
 763
 764         init_completion(&bltd.bltd_comp);
 765         bltd.bltd_num = atomic_read(&blp->blp_num_threads);
 766         snprintf(bltd.bltd_name, sizeof(bltd.bltd_name),
 767                 "ldlm_bl_%02d", bltd.bltd_num);
 768         task = kthread_run(ldlm_bl_thread_main, &bltd, "%s", bltd.bltd_name);
 769         if (IS_ERR(task)) {
 770                 CERROR("cannot start LDLM thread ldlm_bl_%02d: rc %ld\n",
 771                        atomic_read(&blp->blp_num_threads), PTR_ERR(task));
 772                 return PTR_ERR(task);
 773         }
 774         wait_for_completion(&bltd.bltd_comp);
 775
 776         return 0;
 777 }
 778
 779 /**
 780  * Main blocking requests processing thread.
 781  *
 782  * Callers put locks into its queue by calling ldlm_bl_to_thread.
 783  * This thread in the end ends up doing actual call to ->l_blocking_ast
 784  * for queued locks.
 785  */
 786 static int ldlm_bl_thread_main(void *arg)
 787 {
 788         struct ldlm_bl_pool *blp;
 789
 790         {
 791                 struct ldlm_bl_thread_data *bltd = arg;
 792
 793                 blp = bltd->bltd_blp;
 794
 795                 atomic_inc(&blp->blp_num_threads);
 796                 atomic_inc(&blp->blp_busy_threads);
 797
 798                 complete(&bltd->bltd_comp);
 799                 /* cannot use bltd after this, it is only on caller's stack */
 800         }
 801
 802         while (1) {
 803                 struct l_wait_info lwi = { 0 };
 804                 struct ldlm_bl_work_item *blwi = NULL;
 805                 int busy;
 806
 807                 blwi = ldlm_bl_get_work(blp);
 808
 809                 if (blwi == NULL) {
 810                         atomic_dec(&blp->blp_busy_threads);
 811                         l_wait_event_exclusive(blp->blp_waitq,
 812                                          (blwi = ldlm_bl_get_work(blp)) != NULL,
 813                                          &lwi);
 814                         busy = atomic_inc_return(&blp->blp_busy_threads);
 815                 } else {
 816                         busy = atomic_read(&blp->blp_busy_threads);
 817                 }
 818
 819                 if (blwi->blwi_ns == NULL)
 820                         /* added by ldlm_cleanup() */
 821                         break;
 822
 823                 /* Not fatal if racy and have a few too many threads */
 824                 if (unlikely(busy < blp->blp_max_threads &&
 825                              busy >= atomic_read(&blp->blp_num_threads) &&
 826                              !blwi->blwi_mem_pressure))
 827                         /* discard the return value, we tried */
 828                         ldlm_bl_thread_start(blp);
 829
 830                 if (blwi->blwi_mem_pressure)
 831                         memory_pressure_set();
 832
 833                 if (blwi->blwi_count) {
 834                         int count;
 835                         /* The special case when we cancel locks in LRU
 836                          * asynchronously, we pass the list of locks here.
 837                          * Thus locks are marked LDLM_FL_CANCELING, but NOT
 838                          * canceled locally yet. */
 839                         count = ldlm_cli_cancel_list_local(&blwi->blwi_head,
 840                                                            blwi->blwi_count,
 841                                                            LCF_BL_AST);
 842                         ldlm_cli_cancel_list(&blwi->blwi_head, count, NULL,
 843                                              blwi->blwi_flags);
 844                 } else {
 845                         ldlm_handle_bl_callback(blwi->blwi_ns, &blwi->blwi_ld,
 846                                                 blwi->blwi_lock);
 847                 }
 848                 if (blwi->blwi_mem_pressure)
 849                         memory_pressure_clr();
 850
 851                 if (blwi->blwi_flags & LCF_ASYNC)
 852                         OBD_FREE(blwi, sizeof(*blwi));
 853                 else
 854                         complete(&blwi->blwi_comp);
 855         }
 856
 857         atomic_dec(&blp->blp_busy_threads);
 858         atomic_dec(&blp->blp_num_threads);
 859         complete(&blp->blp_comp);
 860         return 0;
 861 }
 862
 863
 864 static int ldlm_setup(void);
 865 static int ldlm_cleanup(void);
 866
 867 int ldlm_get_ref(void)
 868 {
 869         int rc = 0;
 870
 871         mutex_lock(&ldlm_ref_mutex);
 872         if (++ldlm_refcount == 1) {
 873                 rc = ldlm_setup();
 874                 if (rc)
 875                         ldlm_refcount--;
 876         }
 877         mutex_unlock(&ldlm_ref_mutex);
 878
 879         return rc;
 880 }
 881 EXPORT_SYMBOL(ldlm_get_ref);
 882
 883 void ldlm_put_ref(void)
 884 {
 885         mutex_lock(&ldlm_ref_mutex);
 886         if (ldlm_refcount == 1) {
 887                 int rc = ldlm_cleanup();
 888
 889                 if (rc)
 890                         CERROR("ldlm_cleanup failed: %d\n", rc);
 891                 else
 892                         ldlm_refcount--;
 893         } else {
 894                 ldlm_refcount--;
 895         }
 896         mutex_unlock(&ldlm_ref_mutex);
 897 }
 898 EXPORT_SYMBOL(ldlm_put_ref);
 899
 900 /*
 901  * Export handle<->lock hash operations.
 902  */
 903 static unsigned
 904 ldlm_export_lock_hash(struct cfs_hash *hs, const void *key, unsigned mask)
 905 {
 906         return cfs_hash_u64_hash(((struct lustre_handle *)key)->cookie, mask);
 907 }
 908
 909 static void *
 910 ldlm_export_lock_key(struct hlist_node *hnode)
 911 {
 912         struct ldlm_lock *lock;
 913
 914         lock = hlist_entry(hnode, struct ldlm_lock, l_exp_hash);
 915         return &lock->l_remote_handle;
 916 }
 917
 918 static void
 919 ldlm_export_lock_keycpy(struct hlist_node *hnode, void *key)
 920 {
 921         struct ldlm_lock     *lock;
 922
 923         lock = hlist_entry(hnode, struct ldlm_lock, l_exp_hash);
 924         lock->l_remote_handle = *(struct lustre_handle *)key;
 925 }
 926
 927 static int
 928 ldlm_export_lock_keycmp(const void *key, struct hlist_node *hnode)
 929 {
 930         return lustre_handle_equal(ldlm_export_lock_key(hnode), key);
 931 }
 932
 933 static void *
 934 ldlm_export_lock_object(struct hlist_node *hnode)
 935 {
 936         return hlist_entry(hnode, struct ldlm_lock, l_exp_hash);
 937 }
 938
 939 static void
 940 ldlm_export_lock_get(struct cfs_hash *hs, struct hlist_node *hnode)
 941 {
 942         struct ldlm_lock *lock;
 943
 944         lock = hlist_entry(hnode, struct ldlm_lock, l_exp_hash);
 945         LDLM_LOCK_GET(lock);
 946 }
 947
 948 static void
 949 ldlm_export_lock_put(struct cfs_hash *hs, struct hlist_node *hnode)
 950 {
 951         struct ldlm_lock *lock;
 952
 953         lock = hlist_entry(hnode, struct ldlm_lock, l_exp_hash);
 954         LDLM_LOCK_RELEASE(lock);
 955 }
 956
 957 static cfs_hash_ops_t ldlm_export_lock_ops = {
 958         .hs_hash        = ldlm_export_lock_hash,
 959         .hs_key  = ldlm_export_lock_key,
 960         .hs_keycmp      = ldlm_export_lock_keycmp,
 961         .hs_keycpy      = ldlm_export_lock_keycpy,
 962         .hs_object      = ldlm_export_lock_object,
 963         .hs_get  = ldlm_export_lock_get,
 964         .hs_put  = ldlm_export_lock_put,
 965         .hs_put_locked  = ldlm_export_lock_put,
 966 };
 967
 968 int ldlm_init_export(struct obd_export *exp)
 969 {
 970         int rc;
 971
 972         exp->exp_lock_hash =
 973                 cfs_hash_create(obd_uuid2str(&exp->exp_client_uuid),
 974                                 HASH_EXP_LOCK_CUR_BITS,
 975                                 HASH_EXP_LOCK_MAX_BITS,
 976                                 HASH_EXP_LOCK_BKT_BITS, 0,
 977                                 CFS_HASH_MIN_THETA, CFS_HASH_MAX_THETA,
 978                                 &ldlm_export_lock_ops,
 979                                 CFS_HASH_DEFAULT | CFS_HASH_REHASH_KEY |
 980                                 CFS_HASH_NBLK_CHANGE);
 981
 982         if (!exp->exp_lock_hash)
 983                 return -ENOMEM;
 984
 985         rc = ldlm_init_flock_export(exp);
 986         if (rc)
 987                 goto err;
 988
 989         return 0;
 990 err:
 991         ldlm_destroy_export(exp);
 992         return rc;
 993 }
 994 EXPORT_SYMBOL(ldlm_init_export);
 995
 996 void ldlm_destroy_export(struct obd_export *exp)
 997 {
 998         cfs_hash_putref(exp->exp_lock_hash);
 999         exp->exp_lock_hash = NULL;
1000
1001         ldlm_destroy_flock_export(exp);
1002 }
1003 EXPORT_SYMBOL(ldlm_destroy_export);
1004
1005 static int ldlm_setup(void)
1006 {
1007         static struct ptlrpc_service_conf       conf;
1008         struct ldlm_bl_pool                     *blp = NULL;
1009         int rc = 0;
1010         int i;
1011
1012         if (ldlm_state != NULL)
1013                 return -EALREADY;
1014
1015         OBD_ALLOC(ldlm_state, sizeof(*ldlm_state));
1016         if (ldlm_state == NULL)
1017                 return -ENOMEM;
1018
1019         rc = ldlm_proc_setup();
1020         if (rc != 0)
1021                 goto out;
1022
1023         memset(&conf, 0, sizeof(conf));
1024         conf = (typeof(conf)) {
1025                 .psc_name               = "ldlm_cbd",
1026                 .psc_watchdog_factor    = 2,
1027                 .psc_buf                = {
1028                         .bc_nbufs               = LDLM_CLIENT_NBUFS,
1029                         .bc_buf_size            = LDLM_BUFSIZE,
1030                         .bc_req_max_size        = LDLM_MAXREQSIZE,
1031                         .bc_rep_max_size        = LDLM_MAXREPSIZE,
1032                         .bc_req_portal          = LDLM_CB_REQUEST_PORTAL,
1033                         .bc_rep_portal          = LDLM_CB_REPLY_PORTAL,
1034                 },
1035                 .psc_thr                = {
1036                         .tc_thr_name            = "ldlm_cb",
1037                         .tc_thr_factor          = LDLM_THR_FACTOR,
1038                         .tc_nthrs_init          = LDLM_NTHRS_INIT,
1039                         .tc_nthrs_base          = LDLM_NTHRS_BASE,
1040                         .tc_nthrs_max           = LDLM_NTHRS_MAX,
1041                         .tc_nthrs_user          = ldlm_num_threads,
1042                         .tc_cpu_affinity        = 1,
1043                         .tc_ctx_tags            = LCT_MD_THREAD | LCT_DT_THREAD,
1044                 },
1045                 .psc_cpt                = {
1046                         .cc_pattern             = ldlm_cpts,
1047                 },
1048                 .psc_ops                = {
1049                         .so_req_handler         = ldlm_callback_handler,
1050                 },
1051         };
1052         ldlm_state->ldlm_cb_service =
1053                         ptlrpc_register_service(&conf, ldlm_svc_proc_dir);
1054         if (IS_ERR(ldlm_state->ldlm_cb_service)) {
1055                 CERROR("failed to start service\n");
1056                 rc = PTR_ERR(ldlm_state->ldlm_cb_service);
1057                 ldlm_state->ldlm_cb_service = NULL;
1058                 goto out;
1059         }
1060
1061
1062         OBD_ALLOC(blp, sizeof(*blp));
1063         if (blp == NULL) {
1064                 rc = -ENOMEM;
1065                 goto out;
1066         }
1067         ldlm_state->ldlm_bl_pool = blp;
1068
1069         spin_lock_init(&blp->blp_lock);
1070         INIT_LIST_HEAD(&blp->blp_list);
1071         INIT_LIST_HEAD(&blp->blp_prio_list);
1072         init_waitqueue_head(&blp->blp_waitq);
1073         atomic_set(&blp->blp_num_threads, 0);
1074         atomic_set(&blp->blp_busy_threads, 0);
1075
1076         if (ldlm_num_threads == 0) {
1077                 blp->blp_min_threads = LDLM_NTHRS_INIT;
1078                 blp->blp_max_threads = LDLM_NTHRS_MAX;
1079         } else {
1080                 blp->blp_min_threads = blp->blp_max_threads =
1081                         min_t(int, LDLM_NTHRS_MAX, max_t(int, LDLM_NTHRS_INIT,
1082                                                          ldlm_num_threads));
1083         }
1084
1085         for (i = 0; i < blp->blp_min_threads; i++) {
1086                 rc = ldlm_bl_thread_start(blp);
1087                 if (rc < 0)
1088                         goto out;
1089         }
1090
1091
1092         rc = ldlm_pools_init();
1093         if (rc) {
1094                 CERROR("Failed to initialize LDLM pools: %d\n", rc);
1095                 goto out;
1096         }
1097         return 0;
1098
1099  out:
1100         ldlm_cleanup();
1101         return rc;
1102 }
1103
1104 static int ldlm_cleanup(void)
1105 {
1106         if (!list_empty(ldlm_namespace_list(LDLM_NAMESPACE_SERVER)) ||
1107             !list_empty(ldlm_namespace_list(LDLM_NAMESPACE_CLIENT))) {
1108                 CERROR("ldlm still has namespaces; clean these up first.\n");
1109                 ldlm_dump_all_namespaces(LDLM_NAMESPACE_SERVER, D_DLMTRACE);
1110                 ldlm_dump_all_namespaces(LDLM_NAMESPACE_CLIENT, D_DLMTRACE);
1111                 return -EBUSY;
1112         }
1113
1114         ldlm_pools_fini();
1115
1116         if (ldlm_state->ldlm_bl_pool != NULL) {
1117                 struct ldlm_bl_pool *blp = ldlm_state->ldlm_bl_pool;
1118
1119                 while (atomic_read(&blp->blp_num_threads) > 0) {
1120                         struct ldlm_bl_work_item blwi = { .blwi_ns = NULL };
1121
1122                         init_completion(&blp->blp_comp);
1123
1124                         spin_lock(&blp->blp_lock);
1125                         list_add_tail(&blwi.blwi_entry, &blp->blp_list);
1126                         wake_up(&blp->blp_waitq);
1127                         spin_unlock(&blp->blp_lock);
1128
1129                         wait_for_completion(&blp->blp_comp);
1130                 }
1131
1132                 OBD_FREE(blp, sizeof(*blp));
1133         }
1134
1135         if (ldlm_state->ldlm_cb_service != NULL)
1136                 ptlrpc_unregister_service(ldlm_state->ldlm_cb_service);
1137
1138         ldlm_proc_cleanup();
1139
1140
1141         OBD_FREE(ldlm_state, sizeof(*ldlm_state));
1142         ldlm_state = NULL;
1143
1144         return 0;
1145 }
1146
1147 int ldlm_init(void)
1148 {
1149         mutex_init(&ldlm_ref_mutex);
1150         mutex_init(ldlm_namespace_lock(LDLM_NAMESPACE_SERVER));
1151         mutex_init(ldlm_namespace_lock(LDLM_NAMESPACE_CLIENT));
1152         ldlm_resource_slab = kmem_cache_create("ldlm_resources",
1153                                                sizeof(struct ldlm_resource), 0,
1154                                                SLAB_HWCACHE_ALIGN, NULL);
1155         if (ldlm_resource_slab == NULL)
1156                 return -ENOMEM;
1157
1158         ldlm_lock_slab = kmem_cache_create("ldlm_locks",
1159                               sizeof(struct ldlm_lock), 0,
1160                               SLAB_HWCACHE_ALIGN | SLAB_DESTROY_BY_RCU, NULL);
1161         if (ldlm_lock_slab == NULL) {
1162                 kmem_cache_destroy(ldlm_resource_slab);
1163                 return -ENOMEM;
1164         }
1165
1166         ldlm_interval_slab = kmem_cache_create("interval_node",
1167                                         sizeof(struct ldlm_interval),
1168                                         0, SLAB_HWCACHE_ALIGN, NULL);
1169         if (ldlm_interval_slab == NULL) {
1170                 kmem_cache_destroy(ldlm_resource_slab);
1171                 kmem_cache_destroy(ldlm_lock_slab);
1172                 return -ENOMEM;
1173         }
1174 #if LUSTRE_TRACKS_LOCK_EXP_REFS
1175         class_export_dump_hook = ldlm_dump_export_locks;
1176 #endif
1177         return 0;
1178 }
1179
1180 void ldlm_exit(void)
1181 {
1182         if (ldlm_refcount)
1183                 CERROR("ldlm_refcount is %d in ldlm_exit!\n", ldlm_refcount);
1184         kmem_cache_destroy(ldlm_resource_slab);
1185         /* ldlm_lock_put() use RCU to call ldlm_lock_free, so need call
1186          * synchronize_rcu() to wait a grace period elapsed, so that
1187          * ldlm_lock_free() get a chance to be called. */
1188         synchronize_rcu();
1189         kmem_cache_destroy(ldlm_lock_slab);
1190         kmem_cache_destroy(ldlm_interval_slab);
1191 }