lustre/ptlrpc/recov_thread.c

   1 /* -*- mode: c; c-basic-offset: 8; indent-tabs-mode: nil; -*-
   2  * vim:expandtab:shiftwidth=8:tabstop=8:
   3  *
   4  *  Copyright (C) 2003 Cluster File Systems, Inc.
   5  *   Author: Andreas Dilger <adilger@clusterfs.com>
   6  *
   7  *   This file is part of Lustre, http://www.lustre.org.
   8  *
   9  *   Lustre is free software; you can redistribute it and/or
  10  *   modify it under the terms of version 2 of the GNU General Public
  11  *   License as published by the Free Software Foundation.
  12  *
  13  *   Lustre is distributed in the hope that it will be useful,
  14  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  *   GNU General Public License for more details.
  17  *
  18  *   You should have received a copy of the GNU General Public License
  19  *   along with Lustre; if not, write to the Free Software
  20  *   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  21  *
  22  * OST<->MDS recovery logging thread.
  23  *
  24  * Invariants in implementation:
  25  * - we do not share logs among different OST<->MDS connections, so that
  26  *   if an OST or MDS fails it need only look at log(s) relevant to itself
  27  */
  28
  29 #define DEBUG_SUBSYSTEM S_LOG
  30
  31 #ifndef EXPORT_SYMTAB
  32 # define EXPORT_SYMTAB
  33 #endif
  34
  35 #ifdef __KERNEL__
  36 #include <linux/fs.h>
  37 #else
  38 # include <portals/list.h>
  39 # include <liblustre.h>
  40 #endif
  41
  42 #include <linux/kp30.h>
  43 #include <linux/obd_class.h>
  44 #include <linux/lustre_commit_confd.h>
  45 #include <linux/obd_support.h>
  46 #include <linux/obd_class.h>
  47 #include <linux/lustre_net.h>
  48 #include <portals/types.h>
  49 #include <portals/list.h>
  50 #include <linux/lustre_log.h>
  51 #include "ptlrpc_internal.h"
  52
  53 #define LLCD_SIZE 4096
  54
  55 #ifdef __KERNEL__
  56
  57 static struct llog_commit_master lustre_lcm;
  58 static struct llog_commit_master *lcm = &lustre_lcm;
  59
  60 /* Allocate new commit structs in case we do not have enough */
  61 static int llcd_alloc(void)
  62 {
  63         struct llog_canceld_ctxt *llcd;
  64         int offset = offsetof(struct llog_canceld_ctxt, llcd_cookies);
  65
  66         OBD_ALLOC(llcd, LLCD_SIZE + offset);
  67         if (llcd == NULL)
  68                 return -ENOMEM;
  69
  70         llcd->llcd_lcm = lcm;
  71
  72         spin_lock(&lcm->lcm_llcd_lock);
  73         list_add(&llcd->llcd_list, &lcm->lcm_llcd_free);
  74         atomic_inc(&lcm->lcm_llcd_numfree);
  75         spin_unlock(&lcm->lcm_llcd_lock);
  76
  77         return 0;
  78 }
  79
  80 /* Get a free cookie struct from the list */
  81 struct llog_canceld_ctxt *llcd_grab(void)
  82 {
  83         struct llog_canceld_ctxt *llcd;
  84
  85         spin_lock(&lcm->lcm_llcd_lock);
  86         if (list_empty(&lcm->lcm_llcd_free)) {
  87                 spin_unlock(&lcm->lcm_llcd_lock);
  88                 if (llcd_alloc() < 0) {
  89                         CERROR("unable to allocate log commit data!\n");
  90                         return NULL;
  91                 }
  92                 spin_lock(&lcm->lcm_llcd_lock);
  93         }
  94
  95         llcd = list_entry(lcm->lcm_llcd_free.next, typeof(*llcd), llcd_list);
  96         list_del(&llcd->llcd_list);
  97         atomic_dec(&lcm->lcm_llcd_numfree);
  98         spin_unlock(&lcm->lcm_llcd_lock);
  99
 100         llcd->llcd_tries = 0;
 101         llcd->llcd_cookiebytes = 0;
 102
 103         return llcd;
 104 }
 105 EXPORT_SYMBOL(llcd_grab);
 106
 107 static void llcd_put(struct llog_canceld_ctxt *llcd)
 108 {
 109         int offset = offsetof(struct llog_canceld_ctxt, llcd_cookies);
 110
 111         if (atomic_read(&lcm->lcm_llcd_numfree) >= lcm->lcm_llcd_maxfree) {
 112                 OBD_FREE(llcd, LLCD_SIZE + offset);
 113         } else {
 114                 spin_lock(&lcm->lcm_llcd_lock);
 115                 list_add(&llcd->llcd_list, &lcm->lcm_llcd_free);
 116                 atomic_inc(&lcm->lcm_llcd_numfree);
 117                 spin_unlock(&lcm->lcm_llcd_lock);
 118         }
 119 }
 120
 121 /* Send some cookies to the appropriate target */
 122 void llcd_send(struct llog_canceld_ctxt *llcd)
 123 {
 124         spin_lock(&llcd->llcd_lcm->lcm_llcd_lock);
 125         list_add_tail(&llcd->llcd_list, &llcd->llcd_lcm->lcm_llcd_pending);
 126         spin_unlock(&llcd->llcd_lcm->lcm_llcd_lock);
 127
 128         wake_up_nr(&llcd->llcd_lcm->lcm_waitq, 1);
 129 }
 130 EXPORT_SYMBOL(llcd_send);
 131
 132 /* deleted objects have a commit callback that cancels the MDS
 133  * log record for the deletion.  The commit callback calls this
 134  * function
 135  */
 136 int llog_obd_repl_cancel(struct llog_ctxt *ctxt,
 137                          struct lov_stripe_md *lsm, int count,
 138                          struct llog_cookie *cookies, int flags)
 139 {
 140         struct llog_canceld_ctxt *llcd;
 141         int rc = 0;
 142         ENTRY;
 143
 144         LASSERT(ctxt);
 145
 146         if (ctxt->loc_imp == NULL) {
 147                 CWARN("no import for ctxt %p\n", ctxt);
 148                 RETURN(0);
 149         }
 150
 151         if (count == 0 || cookies == NULL) {
 152                 down(&ctxt->loc_sem);
 153                 if (ctxt->loc_llcd == NULL || !(flags & OBD_LLOG_FL_SENDNOW))
 154                         GOTO(out, rc);
 155
 156                 llcd = ctxt->loc_llcd;
 157                 GOTO(send_now, rc);
 158         }
 159
 160         down(&ctxt->loc_sem);
 161         llcd = ctxt->loc_llcd;
 162         if (llcd == NULL) {
 163                 llcd = llcd_grab();
 164                 if (llcd == NULL) {
 165                         CERROR("couldn't get an llcd - dropped "LPX64":%x+%u\n",
 166                                cookies->lgc_lgl.lgl_oid,
 167                                cookies->lgc_lgl.lgl_ogen, cookies->lgc_index);
 168                         GOTO(out, rc = -ENOMEM);
 169                 }
 170                 llcd->llcd_ctxt = ctxt;
 171                 ctxt->loc_llcd = llcd;
 172         }
 173
 174         memcpy((char *)llcd->llcd_cookies + llcd->llcd_cookiebytes, cookies,
 175                sizeof(*cookies));
 176         llcd->llcd_cookiebytes += sizeof(*cookies);
 177
 178 send_now:
 179         if ((LLCD_SIZE - llcd->llcd_cookiebytes < sizeof(*cookies) ||
 180              flags & OBD_LLOG_FL_SENDNOW)) {
 181                 CDEBUG(D_HA, "send llcd %p:%p\n", llcd, llcd->llcd_ctxt);
 182                 ctxt->loc_llcd = NULL;
 183                 llcd_send(llcd);
 184         }
 185 out:
 186         up(&ctxt->loc_sem);
 187         return rc;
 188 }
 189 EXPORT_SYMBOL(llog_obd_repl_cancel);
 190
 191 int llog_obd_repl_sync(struct llog_ctxt *ctxt, struct obd_export *exp)
 192 {
 193         int rc = 0;
 194         ENTRY;
 195
 196         if (exp && (ctxt->loc_imp == exp->exp_imp_reverse)) {
 197                 down(&ctxt->loc_sem);
 198                 if (ctxt->loc_llcd != NULL) {
 199                         CWARN("import will be destroyed, put "
 200                               "llcd %p:%p\n", ctxt->loc_llcd, ctxt);
 201                         llcd_put(ctxt->loc_llcd);
 202                         ctxt->loc_llcd = NULL;
 203                         ctxt->loc_imp = NULL;
 204                 }
 205                 up(&ctxt->loc_sem);
 206         } else {
 207                 rc = llog_cancel(ctxt, NULL, 0, NULL, OBD_LLOG_FL_SENDNOW);
 208         }
 209
 210         RETURN(rc);
 211 }
 212 EXPORT_SYMBOL(llog_obd_repl_sync);
 213
 214 static int log_commit_thread(void *arg)
 215 {
 216         struct llog_commit_master *lcm = arg;
 217         struct llog_commit_daemon *lcd;
 218         struct llog_canceld_ctxt *llcd, *n;
 219         unsigned long flags;
 220         ENTRY;
 221
 222         OBD_ALLOC(lcd, sizeof(*lcd));
 223         if (lcd == NULL)
 224                 RETURN(-ENOMEM);
 225
 226         lock_kernel();
 227         ptlrpc_daemonize(); /* thread never needs to do IO */
 228
 229         SIGNAL_MASK_LOCK(current, flags);
 230         sigfillset(&current->blocked);
 231         RECALC_SIGPENDING;
 232         SIGNAL_MASK_UNLOCK(current, flags);
 233
 234         spin_lock(&lcm->lcm_thread_lock);
 235         THREAD_NAME(current->comm, "ll_log_commit_%d",
 236                     atomic_read(&lcm->lcm_thread_total));
 237         atomic_inc(&lcm->lcm_thread_total);
 238         spin_unlock(&lcm->lcm_thread_lock);
 239         unlock_kernel();
 240
 241         INIT_LIST_HEAD(&lcd->lcd_lcm_list);
 242         INIT_LIST_HEAD(&lcd->lcd_llcd_list);
 243         lcd->lcd_lcm = lcm;
 244
 245         CDEBUG(D_HA, "%s started\n", current->comm);
 246         do {
 247                 struct ptlrpc_request *request;
 248                 struct obd_import *import = NULL;
 249                 struct list_head *sending_list;
 250                 int rc = 0;
 251
 252                 /* If we do not have enough pages available, allocate some */
 253                 while (atomic_read(&lcm->lcm_llcd_numfree) <
 254                        lcm->lcm_llcd_minfree) {
 255                         if (llcd_alloc() < 0)
 256                                 break;
 257                 }
 258
 259                 spin_lock(&lcm->lcm_thread_lock);
 260                 atomic_inc(&lcm->lcm_thread_numidle);
 261                 list_move(&lcd->lcd_lcm_list, &lcm->lcm_thread_idle);
 262                 spin_unlock(&lcm->lcm_thread_lock);
 263
 264                 wait_event_interruptible(lcm->lcm_waitq,
 265                                          !list_empty(&lcm->lcm_llcd_pending) ||
 266                                          lcm->lcm_flags & LLOG_LCM_FL_EXIT);
 267
 268                 /* If we are the last available thread, start a new one in case
 269                  * we get blocked on an RPC (nobody else will start a new one)*/
 270                 spin_lock(&lcm->lcm_thread_lock);
 271                 atomic_dec(&lcm->lcm_thread_numidle);
 272                 list_move(&lcd->lcd_lcm_list, &lcm->lcm_thread_busy);
 273                 spin_unlock(&lcm->lcm_thread_lock);
 274
 275                 sending_list = &lcm->lcm_llcd_pending;
 276         resend:
 277                 if (lcm->lcm_flags & LLOG_LCM_FL_EXIT) {
 278                         lcm->lcm_llcd_maxfree = 0;
 279                         lcm->lcm_llcd_minfree = 0;
 280                         lcm->lcm_thread_max = 0;
 281
 282                         if (list_empty(&lcm->lcm_llcd_pending) ||
 283                             lcm->lcm_flags & LLOG_LCM_FL_EXIT_FORCE)
 284                                 break;
 285                 }
 286
 287                 if (atomic_read(&lcm->lcm_thread_numidle) <= 1 &&
 288                     atomic_read(&lcm->lcm_thread_total) < lcm->lcm_thread_max) {
 289                         rc = llog_start_commit_thread();
 290                         if (rc < 0)
 291                                 CERROR("error starting thread: rc %d\n", rc);
 292                 }
 293
 294                 /* Move all of the pending cancels from the same OST off of
 295                  * the list, so we don't get multiple threads blocked and/or
 296                  * doing upcalls on the same OST in case of failure. */
 297                 spin_lock(&lcm->lcm_llcd_lock);
 298                 if (!list_empty(sending_list)) {
 299                         list_move_tail(sending_list->next,
 300                                        &lcd->lcd_llcd_list);
 301                         llcd = list_entry(lcd->lcd_llcd_list.next,
 302                                           typeof(*llcd), llcd_list);
 303                         LASSERT(llcd->llcd_lcm == lcm);
 304                         import = llcd->llcd_ctxt->loc_imp;
 305                 }
 306                 list_for_each_entry_safe(llcd, n, sending_list, llcd_list) {
 307                         LASSERT(llcd->llcd_lcm == lcm);
 308                         if (import == llcd->llcd_ctxt->loc_imp)
 309                                 list_move_tail(&llcd->llcd_list,
 310                                                &lcd->lcd_llcd_list);
 311                 }
 312                 if (sending_list != &lcm->lcm_llcd_resend) {
 313                         list_for_each_entry_safe(llcd, n, &lcm->lcm_llcd_resend,
 314                                                  llcd_list) {
 315                                 LASSERT(llcd->llcd_lcm == lcm);
 316                                 if (import == llcd->llcd_ctxt->loc_imp)
 317                                         list_move_tail(&llcd->llcd_list,
 318                                                        &lcd->lcd_llcd_list);
 319                         }
 320                 }
 321                 spin_unlock(&lcm->lcm_llcd_lock);
 322
 323                 /* We are the only one manipulating our local list - no lock */
 324                 list_for_each_entry_safe(llcd,n, &lcd->lcd_llcd_list,llcd_list){
 325                         char *bufs[1] = {(char *)llcd->llcd_cookies};
 326
 327                         list_del(&llcd->llcd_list);
 328                         if (llcd->llcd_cookiebytes == 0) {
 329                                 CDEBUG(D_HA, "put empty llcd %p:%p\n",
 330                                        llcd, llcd->llcd_ctxt);
 331                                 llcd_put(llcd);
 332                                 continue;
 333                         }
 334
 335                         down(&llcd->llcd_ctxt->loc_sem);
 336                         if (llcd->llcd_ctxt->loc_imp == NULL) {
 337                                 up(&llcd->llcd_ctxt->loc_sem);
 338                                 CWARN("import will be destroyed, put "
 339                                       "llcd %p:%p\n", llcd, llcd->llcd_ctxt);
 340                                 llcd_put(llcd);
 341                                 continue;
 342                         }
 343
 344                         request = ptlrpc_prep_req(import, OBD_LOG_CANCEL, 1,
 345                                                   &llcd->llcd_cookiebytes,
 346                                                   bufs);
 347                         up(&llcd->llcd_ctxt->loc_sem);
 348
 349                         if (request == NULL) {
 350                                 rc = -ENOMEM;
 351                                 CERROR("error preparing commit: rc %d\n", rc);
 352
 353                                 spin_lock(&lcm->lcm_llcd_lock);
 354                                 list_splice(&lcd->lcd_llcd_list,
 355                                             &lcm->lcm_llcd_resend);
 356                                 INIT_LIST_HEAD(&lcd->lcd_llcd_list);
 357                                 spin_unlock(&lcm->lcm_llcd_lock);
 358                                 break;
 359                         }
 360
 361                         request->rq_replen = lustre_msg_size(0, NULL);
 362                         down(&llcd->llcd_ctxt->loc_sem);
 363                         if (llcd->llcd_ctxt->loc_imp == NULL) {
 364                                 up(&llcd->llcd_ctxt->loc_sem);
 365                                 CWARN("import will be destroyed, put "
 366                                       "llcd %p:%p\n", llcd, llcd->llcd_ctxt);
 367                                 llcd_put(llcd);
 368                                 ptlrpc_req_finished(request);
 369                                 continue;
 370                         }
 371                         rc = ptlrpc_queue_wait(request);
 372                         ptlrpc_req_finished(request);
 373                         up(&llcd->llcd_ctxt->loc_sem);
 374
 375                         /* If the RPC failed, we put this and the remaining
 376                          * messages onto the resend list for another time. */
 377                         if (rc == 0) {
 378                                 llcd_put(llcd);
 379                                 continue;
 380                         }
 381
 382 #if 0                   /* FIXME just put llcd, not put it on resend list */
 383                         spin_lock(&lcm->lcm_llcd_lock);
 384                         list_splice(&lcd->lcd_llcd_list, &lcm->lcm_llcd_resend);
 385                         if (++llcd->llcd_tries < 5) {
 386                                 CERROR("commit %p failed on attempt %d: rc %d\n",
 387                                        llcd, llcd->llcd_tries, rc);
 388
 389                                 list_add_tail(&llcd->llcd_list,
 390                                               &lcm->lcm_llcd_resend);
 391                                 spin_unlock(&lcm->lcm_llcd_lock);
 392                         } else {
 393                                 spin_unlock(&lcm->lcm_llcd_lock);
 394 #endif
 395                                 CERROR("commit %p:%p drop %d cookies: rc %d\n",
 396                                        llcd, llcd->llcd_ctxt,
 397                                        (int)(llcd->llcd_cookiebytes /
 398                                              sizeof(*llcd->llcd_cookies)), rc);
 399                                 llcd_put(llcd);
 400 #if 0
 401                         }
 402                         break;
 403 #endif
 404                 }
 405
 406                 if (rc == 0) {
 407                         sending_list = &lcm->lcm_llcd_resend;
 408                         if (!list_empty(sending_list))
 409                                 goto resend;
 410                 }
 411         } while(1);
 412
 413         /* If we are force exiting, just drop all of the cookies. */
 414         if (lcm->lcm_flags & LLOG_LCM_FL_EXIT_FORCE) {
 415                 spin_lock(&lcm->lcm_llcd_lock);
 416                 list_splice(&lcm->lcm_llcd_pending, &lcd->lcd_llcd_list);
 417                 list_splice(&lcm->lcm_llcd_resend, &lcd->lcd_llcd_list);
 418                 list_splice(&lcm->lcm_llcd_free, &lcd->lcd_llcd_list);
 419                 spin_unlock(&lcm->lcm_llcd_lock);
 420
 421                 list_for_each_entry_safe(llcd, n, &lcd->lcd_llcd_list,llcd_list)
 422                         llcd_put(llcd);
 423         }
 424
 425         spin_lock(&lcm->lcm_thread_lock);
 426         list_del(&lcd->lcd_lcm_list);
 427         spin_unlock(&lcm->lcm_thread_lock);
 428         OBD_FREE(lcd, sizeof(*lcd));
 429
 430         spin_lock(&lcm->lcm_thread_lock);
 431         atomic_dec(&lcm->lcm_thread_total);
 432         spin_unlock(&lcm->lcm_thread_lock);
 433         wake_up(&lcm->lcm_waitq);
 434
 435         CDEBUG(D_HA, "%s exiting\n", current->comm);
 436         return 0;
 437 }
 438
 439 int llog_start_commit_thread(void)
 440 {
 441         int rc;
 442         ENTRY;
 443
 444         if (atomic_read(&lcm->lcm_thread_total) >= lcm->lcm_thread_max)
 445                 RETURN(0);
 446
 447         rc = kernel_thread(log_commit_thread, lcm, CLONE_VM | CLONE_FILES);
 448         if (rc < 0) {
 449                 CERROR("error starting thread #%d: %d\n",
 450                        atomic_read(&lcm->lcm_thread_total), rc);
 451                 RETURN(rc);
 452         }
 453
 454         RETURN(0);
 455 }
 456 EXPORT_SYMBOL(llog_start_commit_thread);
 457
 458 static struct llog_process_args {
 459         struct semaphore         llpa_sem;
 460         struct llog_ctxt        *llpa_ctxt;
 461         void                    *llpa_cb;
 462         void                    *llpa_arg;
 463 } llpa;
 464
 465 int llog_init_commit_master(void)
 466 {
 467         INIT_LIST_HEAD(&lcm->lcm_thread_busy);
 468         INIT_LIST_HEAD(&lcm->lcm_thread_idle);
 469         spin_lock_init(&lcm->lcm_thread_lock);
 470         atomic_set(&lcm->lcm_thread_numidle, 0);
 471         init_waitqueue_head(&lcm->lcm_waitq);
 472         INIT_LIST_HEAD(&lcm->lcm_llcd_pending);
 473         INIT_LIST_HEAD(&lcm->lcm_llcd_resend);
 474         INIT_LIST_HEAD(&lcm->lcm_llcd_free);
 475         spin_lock_init(&lcm->lcm_llcd_lock);
 476         atomic_set(&lcm->lcm_llcd_numfree, 0);
 477         lcm->lcm_llcd_minfree = 0;
 478         lcm->lcm_thread_max = 5;
 479         /* FIXME initialize semaphore for llog_process_args */
 480         sema_init(&llpa.llpa_sem, 1);
 481         return 0;
 482 }
 483
 484 int llog_cleanup_commit_master(int force)
 485 {
 486         lcm->lcm_flags |= LLOG_LCM_FL_EXIT;
 487         if (force)
 488                 lcm->lcm_flags |= LLOG_LCM_FL_EXIT_FORCE;
 489         wake_up(&lcm->lcm_waitq);
 490
 491         wait_event_interruptible(lcm->lcm_waitq,
 492                                  atomic_read(&lcm->lcm_thread_total) == 0);
 493         return 0;
 494 }
 495
 496 static int log_process_thread(void *args)
 497 {
 498         struct llog_process_args *data = args;
 499         struct llog_ctxt *ctxt = data->llpa_ctxt;
 500         void   *cb = data->llpa_cb;
 501         struct llog_logid logid = *(struct llog_logid *)(data->llpa_arg);
 502         struct llog_handle *llh = NULL;
 503         unsigned long flags;
 504         int rc;
 505         ENTRY;
 506
 507         up(&data->llpa_sem);
 508         lock_kernel();
 509         ptlrpc_daemonize(); /* thread never needs to do IO */
 510
 511         SIGNAL_MASK_LOCK(current, flags);
 512         sigfillset(&current->blocked);
 513         RECALC_SIGPENDING;
 514         SIGNAL_MASK_UNLOCK(current, flags);
 515         unlock_kernel();
 516
 517         rc = llog_create(ctxt, &llh, &logid, NULL);
 518         if (rc) {
 519                 CERROR("llog_create failed %d\n", rc);
 520                 RETURN(rc);
 521         }
 522         rc = llog_init_handle(llh, LLOG_F_IS_CAT, NULL);
 523         if (rc) {
 524                 CERROR("llog_init_handle failed %d\n", rc);
 525                 GOTO(out, rc);
 526         }
 527
 528         if (cb) {
 529                 rc = llog_cat_process(llh, (llog_cb_t)cb, NULL);
 530                 if (rc != LLOG_PROC_BREAK)
 531                         CERROR("llog_cat_process failed %d\n", rc);
 532         } else {
 533                 CWARN("no callback function for recovery\n");
 534         }
 535
 536         CDEBUG(D_HA, "send llcd %p:%p forcibly after recovery\n",
 537                ctxt->loc_llcd, ctxt);
 538         llog_sync(ctxt, NULL);
 539 out:
 540         rc = llog_cat_put(llh);
 541         if (rc)
 542                 CERROR("llog_cat_put failed %d\n", rc);
 543
 544         RETURN(rc);
 545 }
 546
 547 static int llog_recovery_generic(struct llog_ctxt *ctxt, void *handle,void *arg)
 548 {
 549         int rc;
 550         ENTRY;
 551
 552         down(&llpa.llpa_sem);
 553         llpa.llpa_ctxt = ctxt;
 554         llpa.llpa_cb = handle;
 555         llpa.llpa_arg = arg;
 556
 557         rc = kernel_thread(log_process_thread, &llpa, CLONE_VM | CLONE_FILES);
 558         if (rc < 0)
 559                 CERROR("error starting log_process_thread: %d\n", rc);
 560         else {
 561                 CDEBUG(D_HA, "log_process_thread: %d\n", rc);
 562                 rc = 0;
 563         }
 564
 565         RETURN(rc);
 566 }
 567
 568 int llog_repl_connect(struct llog_ctxt *ctxt, int count,
 569                       struct llog_logid *logid, struct llog_gen *gen,
 570                       struct obd_uuid *uuid)
 571 {
 572         struct llog_canceld_ctxt *llcd;
 573         int rc;
 574         ENTRY;
 575
 576         /* send back llcd before recovery from llog */
 577         if (ctxt->loc_llcd != NULL) {
 578                 CWARN("llcd %p:%p not empty\n", ctxt->loc_llcd, ctxt);
 579                 llog_sync(ctxt, NULL);
 580         }
 581
 582         down(&ctxt->loc_sem);
 583         ctxt->loc_gen = *gen;
 584         llcd = llcd_grab();
 585         if (llcd == NULL) {
 586                 CERROR("couldn't get an llcd\n");
 587                 up(&ctxt->loc_sem);
 588                 RETURN(-ENOMEM);
 589         }
 590         llcd->llcd_ctxt = ctxt;
 591         ctxt->loc_llcd = llcd;
 592         up(&ctxt->loc_sem);
 593
 594         rc = llog_recovery_generic(ctxt, ctxt->llog_proc_cb, logid);
 595         if (rc != 0)
 596                 CERROR("error recovery process: %d\n", rc);
 597
 598         RETURN(rc);
 599 }
 600 EXPORT_SYMBOL(llog_repl_connect);
 601
 602 #else /* !__KERNEL__ */
 603
 604 int llog_obd_repl_cancel(struct llog_ctxt *ctxt,
 605                          struct lov_stripe_md *lsm, int count,
 606                          struct llog_cookie *cookies, int flags)
 607 {
 608         return 0;
 609 }
 610 #endif