lustre/obdclass/llog.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 /*
  31  * This file is part of Lustre, http://www.lustre.org/
  32  * Lustre is a trademark of Sun Microsystems, Inc.
  33  *
  34  * lustre/obdclass/llog.c
  35  *
  36  * OST<->MDS recovery logging infrastructure.
  37  * Invariants in implementation:
  38  * - we do not share logs among different OST<->MDS connections, so that
  39  *   if an OST or MDS fails it need only look at log(s) relevant to itself
  40  *
  41  * Author: Andreas Dilger <adilger@clusterfs.com>
  42  * Author: Alex Zhuravlev <bzzz@whamcloud.com>
  43  * Author: Mikhail Pershin <tappro@whamcloud.com>
  44  */
  45
  46 #define DEBUG_SUBSYSTEM S_LOG
  47
  48 #ifndef __KERNEL__
  49 #include <liblustre.h>
  50 #endif
  51
  52 #include <obd_class.h>
  53 #include <lustre_log.h>
  54 #include "llog_internal.h"
  55
  56 /*
  57  * Allocate a new log or catalog handle
  58  * Used inside llog_open().
  59  */
  60 struct llog_handle *llog_alloc_handle(void)
  61 {
  62         struct llog_handle *loghandle;
  63
  64         OBD_ALLOC_PTR(loghandle);
  65         if (loghandle == NULL)
  66                 return ERR_PTR(-ENOMEM);
  67
  68         cfs_init_rwsem(&loghandle->lgh_lock);
  69         cfs_spin_lock_init(&loghandle->lgh_hdr_lock);
  70         CFS_INIT_LIST_HEAD(&loghandle->u.phd.phd_entry);
  71
  72         return loghandle;
  73 }
  74
  75 /*
  76  * Free llog handle and header data if exists. Used in llog_close() only
  77  */
  78 void llog_free_handle(struct llog_handle *loghandle)
  79 {
  80         if (!loghandle)
  81                 return;
  82
  83         if (!loghandle->lgh_hdr)
  84                 goto out;
  85         if (loghandle->lgh_hdr->llh_flags & LLOG_F_IS_PLAIN)
  86                 cfs_list_del_init(&loghandle->u.phd.phd_entry);
  87         if (loghandle->lgh_hdr->llh_flags & LLOG_F_IS_CAT)
  88                 LASSERT(cfs_list_empty(&loghandle->u.chd.chd_head));
  89         LASSERT(sizeof(*(loghandle->lgh_hdr)) == LLOG_CHUNK_SIZE);
  90         OBD_FREE(loghandle->lgh_hdr, LLOG_CHUNK_SIZE);
  91
  92 out:
  93         OBD_FREE_PTR(loghandle);
  94 }
  95
  96 /* returns negative on error; 0 if success; 1 if success & log destroyed */
  97 int llog_cancel_rec(const struct lu_env *env, struct llog_handle *loghandle,
  98                     int index)
  99 {
 100         struct llog_log_hdr *llh = loghandle->lgh_hdr;
 101         int rc = 0;
 102         ENTRY;
 103
 104         CDEBUG(D_RPCTRACE, "Canceling %d in log "LPX64"\n",
 105                index, loghandle->lgh_id.lgl_oid);
 106
 107         if (index == 0) {
 108                 CERROR("Can't cancel index 0 which is header\n");
 109                 RETURN(-EINVAL);
 110         }
 111
 112         cfs_spin_lock(&loghandle->lgh_hdr_lock);
 113         if (!ext2_clear_bit(index, llh->llh_bitmap)) {
 114                 cfs_spin_unlock(&loghandle->lgh_hdr_lock);
 115                 CDEBUG(D_RPCTRACE, "Catalog index %u already clear?\n", index);
 116                 RETURN(-ENOENT);
 117         }
 118
 119         llh->llh_count--;
 120
 121         if ((llh->llh_flags & LLOG_F_ZAP_WHEN_EMPTY) &&
 122             (llh->llh_count == 1) &&
 123             (loghandle->lgh_last_idx == (LLOG_BITMAP_BYTES * 8) - 1)) {
 124                 cfs_spin_unlock(&loghandle->lgh_hdr_lock);
 125                 rc = llog_destroy(env, loghandle);
 126                 if (rc < 0) {
 127                         CERROR("%s: can't destroy empty llog #"LPX64"#"LPX64
 128                                "#%08x: rc = %d\n",
 129                                loghandle->lgh_ctxt->loc_obd->obd_name,
 130                                loghandle->lgh_id.lgl_oid,
 131                                loghandle->lgh_id.lgl_oseq,
 132                                loghandle->lgh_id.lgl_ogen, rc);
 133                         GOTO(out_err, rc);
 134                 }
 135                 RETURN(1);
 136         }
 137         cfs_spin_unlock(&loghandle->lgh_hdr_lock);
 138
 139         rc = llog_write_rec(env, loghandle, &llh->llh_hdr, NULL, 0, NULL, 0);
 140         if (rc < 0) {
 141                 CERROR("%s: fail to write header for llog #"LPX64"#"LPX64
 142                        "#%08x: rc = %d\n",
 143                        loghandle->lgh_ctxt->loc_obd->obd_name,
 144                        loghandle->lgh_id.lgl_oid,
 145                        loghandle->lgh_id.lgl_oseq,
 146                        loghandle->lgh_id.lgl_ogen, rc);
 147                 GOTO(out_err, rc);
 148         }
 149         RETURN(0);
 150 out_err:
 151         cfs_spin_lock(&loghandle->lgh_hdr_lock);
 152         ext2_set_bit(index, llh->llh_bitmap);
 153         llh->llh_count++;
 154         cfs_spin_unlock(&loghandle->lgh_hdr_lock);
 155         return rc;
 156 }
 157 EXPORT_SYMBOL(llog_cancel_rec);
 158
 159 static int llog_read_header(const struct lu_env *env,
 160                             struct llog_handle *handle,
 161                             struct obd_uuid *uuid)
 162 {
 163         struct llog_operations *lop;
 164         int rc;
 165
 166         rc = llog_handle2ops(handle, &lop);
 167         if (rc)
 168                 RETURN(rc);
 169
 170         if (lop->lop_read_header == NULL)
 171                 RETURN(-EOPNOTSUPP);
 172
 173         rc = lop->lop_read_header(env, handle);
 174         if (rc == LLOG_EEMPTY) {
 175                 struct llog_log_hdr *llh = handle->lgh_hdr;
 176
 177                 handle->lgh_last_idx = 0; /* header is record with index 0 */
 178                 llh->llh_count = 1;         /* for the header record */
 179                 llh->llh_hdr.lrh_type = LLOG_HDR_MAGIC;
 180                 llh->llh_hdr.lrh_len = llh->llh_tail.lrt_len = LLOG_CHUNK_SIZE;
 181                 llh->llh_hdr.lrh_index = llh->llh_tail.lrt_index = 0;
 182                 llh->llh_timestamp = cfs_time_current_sec();
 183                 if (uuid)
 184                         memcpy(&llh->llh_tgtuuid, uuid,
 185                                sizeof(llh->llh_tgtuuid));
 186                 llh->llh_bitmap_offset = offsetof(typeof(*llh), llh_bitmap);
 187                 ext2_set_bit(0, llh->llh_bitmap);
 188                 rc = 0;
 189         }
 190         return rc;
 191 }
 192
 193 int llog_init_handle(const struct lu_env *env, struct llog_handle *handle,
 194                      int flags, struct obd_uuid *uuid)
 195 {
 196         struct llog_log_hdr     *llh;
 197         int                      rc;
 198
 199         ENTRY;
 200         LASSERT(handle->lgh_hdr == NULL);
 201
 202         OBD_ALLOC_PTR(llh);
 203         if (llh == NULL)
 204                 RETURN(-ENOMEM);
 205         handle->lgh_hdr = llh;
 206         /* first assign flags to use llog_client_ops */
 207         llh->llh_flags = flags;
 208         rc = llog_read_header(env, handle, uuid);
 209         if (rc == 0) {
 210                 if (unlikely((llh->llh_flags & LLOG_F_IS_PLAIN &&
 211                               flags & LLOG_F_IS_CAT) ||
 212                              (llh->llh_flags & LLOG_F_IS_CAT &&
 213                               flags & LLOG_F_IS_PLAIN))) {
 214                         CERROR("%s: llog type is %s but initializing %s\n",
 215                                handle->lgh_ctxt->loc_obd->obd_name,
 216                                llh->llh_flags & LLOG_F_IS_CAT ?
 217                                "catalog" : "plain",
 218                                flags & LLOG_F_IS_CAT ? "catalog" : "plain");
 219                         GOTO(out, rc = -EINVAL);
 220                 } else if (llh->llh_flags &
 221                            (LLOG_F_IS_PLAIN | LLOG_F_IS_CAT)) {
 222                         /*
 223                          * it is possible to open llog without specifying llog
 224                          * type so it is taken from llh_flags
 225                          */
 226                         flags = llh->llh_flags;
 227                 } else {
 228                         /* for some reason the llh_flags has no type set */
 229                         CERROR("llog type is not specified!\n");
 230                         GOTO(out, rc = -EINVAL);
 231                 }
 232                 if (unlikely(uuid &&
 233                              !obd_uuid_equals(uuid, &llh->llh_tgtuuid))) {
 234                         CERROR("%s: llog uuid mismatch: %s/%s\n",
 235                                handle->lgh_ctxt->loc_obd->obd_name,
 236                                (char *)uuid->uuid,
 237                                (char *)llh->llh_tgtuuid.uuid);
 238                         GOTO(out, rc = -EEXIST);
 239                 }
 240         }
 241         if (flags & LLOG_F_IS_CAT) {
 242                 LASSERT(cfs_list_empty(&handle->u.chd.chd_head));
 243                 CFS_INIT_LIST_HEAD(&handle->u.chd.chd_head);
 244                 llh->llh_size = sizeof(struct llog_logid_rec);
 245         } else if (!(flags & LLOG_F_IS_PLAIN)) {
 246                 CERROR("%s: unknown flags: %#x (expected %#x or %#x)\n",
 247                        handle->lgh_ctxt->loc_obd->obd_name,
 248                        flags, LLOG_F_IS_CAT, LLOG_F_IS_PLAIN);
 249                 rc = -EINVAL;
 250         }
 251 out:
 252         if (rc) {
 253                 OBD_FREE_PTR(llh);
 254                 handle->lgh_hdr = NULL;
 255         }
 256         RETURN(rc);
 257 }
 258 EXPORT_SYMBOL(llog_init_handle);
 259
 260 static int llog_process_thread(void *arg)
 261 {
 262         struct llog_process_info        *lpi = arg;
 263         struct llog_handle              *loghandle = lpi->lpi_loghandle;
 264         struct llog_log_hdr             *llh = loghandle->lgh_hdr;
 265         struct llog_process_cat_data    *cd  = lpi->lpi_catdata;
 266         char                            *buf;
 267         __u64                            cur_offset = LLOG_CHUNK_SIZE;
 268         __u64                            last_offset;
 269         int                              rc = 0, index = 1, last_index;
 270         int                              saved_index = 0;
 271         int                              last_called_index = 0;
 272
 273         ENTRY;
 274
 275         LASSERT(llh);
 276
 277         OBD_ALLOC(buf, LLOG_CHUNK_SIZE);
 278         if (!buf) {
 279                 lpi->lpi_rc = -ENOMEM;
 280                 RETURN(0);
 281         }
 282
 283         if (cd != NULL) {
 284                 last_called_index = cd->lpcd_first_idx;
 285                 index = cd->lpcd_first_idx + 1;
 286         }
 287         if (cd != NULL && cd->lpcd_last_idx)
 288                 last_index = cd->lpcd_last_idx;
 289         else
 290                 last_index = LLOG_BITMAP_BYTES * 8 - 1;
 291
 292         while (rc == 0) {
 293                 struct llog_rec_hdr *rec;
 294
 295                 /* skip records not set in bitmap */
 296                 while (index <= last_index &&
 297                        !ext2_test_bit(index, llh->llh_bitmap))
 298                         ++index;
 299
 300                 LASSERT(index <= last_index + 1);
 301                 if (index == last_index + 1)
 302                         break;
 303 repeat:
 304                 CDEBUG(D_OTHER, "index: %d last_index %d\n",
 305                        index, last_index);
 306
 307                 /* get the buf with our target record; avoid old garbage */
 308                 memset(buf, 0, LLOG_CHUNK_SIZE);
 309                 last_offset = cur_offset;
 310                 rc = llog_next_block(lpi->lpi_env, loghandle, &saved_index,
 311                                      index, &cur_offset, buf, LLOG_CHUNK_SIZE);
 312                 if (rc)
 313                         GOTO(out, rc);
 314
 315                 /* NB: when rec->lrh_len is accessed it is already swabbed
 316                  * since it is used at the "end" of the loop and the rec
 317                  * swabbing is done at the beginning of the loop. */
 318                 for (rec = (struct llog_rec_hdr *)buf;
 319                      (char *)rec < buf + LLOG_CHUNK_SIZE;
 320                      rec = (struct llog_rec_hdr *)((char *)rec + rec->lrh_len)){
 321
 322                         CDEBUG(D_OTHER, "processing rec 0x%p type %#x\n",
 323                                rec, rec->lrh_type);
 324
 325                         if (LLOG_REC_HDR_NEEDS_SWABBING(rec))
 326                                 lustre_swab_llog_rec(rec);
 327
 328                         CDEBUG(D_OTHER, "after swabbing, type=%#x idx=%d\n",
 329                                rec->lrh_type, rec->lrh_index);
 330
 331                         if (rec->lrh_index == 0) {
 332                                 /* probably another rec just got added? */
 333                                 if (index <= loghandle->lgh_last_idx)
 334                                         GOTO(repeat, rc = 0);
 335                                 GOTO(out, rc = 0); /* no more records */
 336                         }
 337                         if (rec->lrh_len == 0 ||
 338                             rec->lrh_len > LLOG_CHUNK_SIZE) {
 339                                 CWARN("invalid length %d in llog record for "
 340                                       "index %d/%d\n", rec->lrh_len,
 341                                       rec->lrh_index, index);
 342                                 GOTO(out, rc = -EINVAL);
 343                         }
 344
 345                         if (rec->lrh_index < index) {
 346                                 CDEBUG(D_OTHER, "skipping lrh_index %d\n",
 347                                        rec->lrh_index);
 348                                 continue;
 349                         }
 350
 351                         CDEBUG(D_OTHER,
 352                                "lrh_index: %d lrh_len: %d (%d remains)\n",
 353                                rec->lrh_index, rec->lrh_len,
 354                                (int)(buf + LLOG_CHUNK_SIZE - (char *)rec));
 355
 356                         loghandle->lgh_cur_idx = rec->lrh_index;
 357                         loghandle->lgh_cur_offset = (char *)rec - (char *)buf +
 358                                                     last_offset;
 359
 360                         /* if set, process the callback on this record */
 361                         if (ext2_test_bit(index, llh->llh_bitmap)) {
 362                                 rc = lpi->lpi_cb(lpi->lpi_env, loghandle, rec,
 363                                                  lpi->lpi_cbdata);
 364                                 last_called_index = index;
 365                                 if (rc == LLOG_PROC_BREAK) {
 366                                         GOTO(out, rc);
 367                                 } else if (rc == LLOG_DEL_RECORD) {
 368                                         llog_cancel_rec(lpi->lpi_env,
 369                                                         loghandle,
 370                                                         rec->lrh_index);
 371                                         rc = 0;
 372                                 }
 373                                 if (rc)
 374                                         GOTO(out, rc);
 375                         } else {
 376                                 CDEBUG(D_OTHER, "Skipped index %d\n", index);
 377                         }
 378
 379                         /* next record, still in buffer? */
 380                         ++index;
 381                         if (index > last_index)
 382                                 GOTO(out, rc = 0);
 383                 }
 384         }
 385
 386 out:
 387         if (cd != NULL)
 388                 cd->lpcd_last_idx = last_called_index;
 389
 390         OBD_FREE(buf, LLOG_CHUNK_SIZE);
 391         lpi->lpi_rc = rc;
 392         return 0;
 393 }
 394
 395 #ifdef __KERNEL__
 396 static int llog_process_thread_daemonize(void *arg)
 397 {
 398         struct llog_process_info        *lpi = arg;
 399         struct lu_env                    env;
 400         int                              rc;
 401
 402         cfs_daemonize_ctxt("llog_process_thread");
 403
 404         /* client env has no keys, tags is just 0 */
 405         rc = lu_env_init(&env, LCT_LOCAL);
 406         if (rc)
 407                 goto out;
 408         lpi->lpi_env = &env;
 409
 410         rc = llog_process_thread(arg);
 411
 412         lu_env_fini(&env);
 413 out:
 414         cfs_complete(&lpi->lpi_completion);
 415         return rc;
 416 }
 417 #endif
 418
 419 int llog_process_or_fork(const struct lu_env *env,
 420                          struct llog_handle *loghandle,
 421                          llog_cb_t cb, void *data, void *catdata, bool fork)
 422 {
 423         struct llog_process_info *lpi;
 424         int                      rc;
 425
 426         ENTRY;
 427
 428         OBD_ALLOC_PTR(lpi);
 429         if (lpi == NULL) {
 430                 CERROR("cannot alloc pointer\n");
 431                 RETURN(-ENOMEM);
 432         }
 433         lpi->lpi_loghandle = loghandle;
 434         lpi->lpi_cb        = cb;
 435         lpi->lpi_cbdata    = data;
 436         lpi->lpi_catdata   = catdata;
 437
 438 #ifdef __KERNEL__
 439         if (fork) {
 440                 /* The new thread can't use parent env,
 441                  * init the new one in llog_process_thread_daemonize. */
 442                 lpi->lpi_env = NULL;
 443                 cfs_init_completion(&lpi->lpi_completion);
 444                 rc = cfs_create_thread(llog_process_thread_daemonize, lpi,
 445                                        CFS_DAEMON_FLAGS);
 446                 if (rc < 0) {
 447                         CERROR("%s: cannot start thread: rc = %d\n",
 448                                loghandle->lgh_ctxt->loc_obd->obd_name, rc);
 449                         OBD_FREE_PTR(lpi);
 450                         RETURN(rc);
 451                 }
 452                 cfs_wait_for_completion(&lpi->lpi_completion);
 453         } else {
 454                 lpi->lpi_env = env;
 455                 llog_process_thread(lpi);
 456         }
 457 #else
 458         lpi->lpi_env = env;
 459         llog_process_thread(lpi);
 460 #endif
 461         rc = lpi->lpi_rc;
 462         OBD_FREE_PTR(lpi);
 463         RETURN(rc);
 464 }
 465
 466 int llog_process(const struct lu_env *env, struct llog_handle *loghandle,
 467                  llog_cb_t cb, void *data, void *catdata)
 468 {
 469         return llog_process_or_fork(env, loghandle, cb, data, catdata, true);
 470 }
 471 EXPORT_SYMBOL(llog_process);
 472
 473 inline int llog_get_size(struct llog_handle *loghandle)
 474 {
 475         if (loghandle && loghandle->lgh_hdr)
 476                 return loghandle->lgh_hdr->llh_count;
 477         return 0;
 478 }
 479 EXPORT_SYMBOL(llog_get_size);
 480
 481 int llog_reverse_process(const struct lu_env *env,
 482                          struct llog_handle *loghandle, llog_cb_t cb,
 483                          void *data, void *catdata)
 484 {
 485         struct llog_log_hdr *llh = loghandle->lgh_hdr;
 486         struct llog_process_cat_data *cd = catdata;
 487         void *buf;
 488         int rc = 0, first_index = 1, index, idx;
 489         ENTRY;
 490
 491         OBD_ALLOC(buf, LLOG_CHUNK_SIZE);
 492         if (!buf)
 493                 RETURN(-ENOMEM);
 494
 495         if (cd != NULL)
 496                 first_index = cd->lpcd_first_idx + 1;
 497         if (cd != NULL && cd->lpcd_last_idx)
 498                 index = cd->lpcd_last_idx;
 499         else
 500                 index = LLOG_BITMAP_BYTES * 8 - 1;
 501
 502         while (rc == 0) {
 503                 struct llog_rec_hdr *rec;
 504                 struct llog_rec_tail *tail;
 505
 506                 /* skip records not set in bitmap */
 507                 while (index >= first_index &&
 508                        !ext2_test_bit(index, llh->llh_bitmap))
 509                         --index;
 510
 511                 LASSERT(index >= first_index - 1);
 512                 if (index == first_index - 1)
 513                         break;
 514
 515                 /* get the buf with our target record; avoid old garbage */
 516                 memset(buf, 0, LLOG_CHUNK_SIZE);
 517                 rc = llog_prev_block(env, loghandle, index, buf,
 518                                      LLOG_CHUNK_SIZE);
 519                 if (rc)
 520                         GOTO(out, rc);
 521
 522                 rec = buf;
 523                 idx = rec->lrh_index;
 524                 CDEBUG(D_RPCTRACE, "index %u : idx %u\n", index, idx);
 525                 while (idx < index) {
 526                         rec = (void *)rec + rec->lrh_len;
 527                         if (LLOG_REC_HDR_NEEDS_SWABBING(rec))
 528                                 lustre_swab_llog_rec(rec);
 529                         idx ++;
 530                 }
 531                 LASSERT(idx == index);
 532                 tail = (void *)rec + rec->lrh_len - sizeof(*tail);
 533
 534                 /* process records in buffer, starting where we found one */
 535                 while ((void *)tail > buf) {
 536                         if (tail->lrt_index == 0)
 537                                 GOTO(out, rc = 0); /* no more records */
 538
 539                         /* if set, process the callback on this record */
 540                         if (ext2_test_bit(index, llh->llh_bitmap)) {
 541                                 rec = (void *)tail - tail->lrt_len +
 542                                       sizeof(*tail);
 543
 544                                 rc = cb(env, loghandle, rec, data);
 545                                 if (rc == LLOG_PROC_BREAK) {
 546                                         GOTO(out, rc);
 547                                 } else if (rc == LLOG_DEL_RECORD) {
 548                                         llog_cancel_rec(env, loghandle,
 549                                                         tail->lrt_index);
 550                                         rc = 0;
 551                                 }
 552                                 if (rc)
 553                                         GOTO(out, rc);
 554                         }
 555
 556                         /* previous record, still in buffer? */
 557                         --index;
 558                         if (index < first_index)
 559                                 GOTO(out, rc = 0);
 560                         tail = (void *)tail - tail->lrt_len;
 561                 }
 562         }
 563
 564 out:
 565         if (buf)
 566                 OBD_FREE(buf, LLOG_CHUNK_SIZE);
 567         RETURN(rc);
 568 }
 569 EXPORT_SYMBOL(llog_reverse_process);
 570
 571 /**
 572  * Helper function to open llog or create it if doesn't exist.
 573  * It hides all transaction handling from caller.
 574  */
 575 int llog_open_create(const struct lu_env *env, struct llog_ctxt *ctxt,
 576                      struct llog_handle **res, struct llog_logid *logid,
 577                      char *name)
 578 {
 579         struct thandle  *th;
 580         int              rc;
 581
 582         ENTRY;
 583
 584         rc = llog_open(env, ctxt, res, logid, name, LLOG_OPEN_NEW);
 585         if (rc)
 586                 RETURN(rc);
 587
 588         if (llog_exist(*res))
 589                 RETURN(0);
 590
 591         if ((*res)->lgh_obj != NULL) {
 592                 struct dt_device *d;
 593
 594                 d = lu2dt_dev((*res)->lgh_obj->do_lu.lo_dev);
 595
 596                 th = dt_trans_create(env, d);
 597                 if (IS_ERR(th))
 598                         GOTO(out, rc = PTR_ERR(th));
 599
 600                 rc = llog_declare_create(env, *res, th);
 601                 if (rc == 0) {
 602                         rc = dt_trans_start_local(env, d, th);
 603                         if (rc == 0)
 604                                 rc = llog_create(env, *res, th);
 605                 }
 606                 dt_trans_stop(env, d, th);
 607         } else {
 608                 /* lvfs compat code */
 609                 LASSERT((*res)->lgh_file == NULL);
 610                 rc = llog_create(env, *res, NULL);
 611         }
 612 out:
 613         if (rc)
 614                 llog_close(env, *res);
 615         RETURN(rc);
 616 }
 617 EXPORT_SYMBOL(llog_open_create);
 618
 619 /**
 620  * Helper function to delete existent llog.
 621  */
 622 int llog_erase(const struct lu_env *env, struct llog_ctxt *ctxt,
 623                struct llog_logid *logid, char *name)
 624 {
 625         struct llog_handle      *handle;
 626         int                      rc = 0, rc2;
 627
 628         ENTRY;
 629
 630         /* nothing to erase */
 631         if (name == NULL && logid == NULL)
 632                 RETURN(0);
 633
 634         rc = llog_open(env, ctxt, &handle, logid, name, LLOG_OPEN_EXISTS);
 635         if (rc < 0)
 636                 RETURN(rc);
 637
 638         rc = llog_init_handle(env, handle, LLOG_F_IS_PLAIN, NULL);
 639         if (rc == 0)
 640                 rc = llog_destroy(env, handle);
 641
 642         rc2 = llog_close(env, handle);
 643         if (rc == 0)
 644                 rc = rc2;
 645         RETURN(rc);
 646 }
 647 EXPORT_SYMBOL(llog_erase);
 648
 649 int llog_open(const struct lu_env *env, struct llog_ctxt *ctxt,
 650               struct llog_handle **lgh, struct llog_logid *logid,
 651               char *name, enum llog_open_param open_param)
 652 {
 653         int      raised;
 654         int      rc;
 655
 656         ENTRY;
 657
 658         LASSERT(ctxt);
 659         LASSERT(ctxt->loc_logops);
 660
 661         if (ctxt->loc_logops->lop_open == NULL) {
 662                 *lgh = NULL;
 663                 RETURN(-EOPNOTSUPP);
 664         }
 665
 666         *lgh = llog_alloc_handle();
 667         if (*lgh == NULL)
 668                 RETURN(-ENOMEM);
 669         (*lgh)->lgh_ctxt = ctxt;
 670         (*lgh)->lgh_logops = ctxt->loc_logops;
 671
 672         raised = cfs_cap_raised(CFS_CAP_SYS_RESOURCE);
 673         if (!raised)
 674                 cfs_cap_raise(CFS_CAP_SYS_RESOURCE);
 675         rc = ctxt->loc_logops->lop_open(env, *lgh, logid, name, open_param);
 676         if (!raised)
 677                 cfs_cap_lower(CFS_CAP_SYS_RESOURCE);
 678         if (rc) {
 679                 llog_free_handle(*lgh);
 680                 *lgh = NULL;
 681         }
 682         RETURN(rc);
 683 }
 684 EXPORT_SYMBOL(llog_open);
 685
 686 int llog_close(const struct lu_env *env, struct llog_handle *loghandle)
 687 {
 688         struct llog_operations  *lop;
 689         int                      rc;
 690
 691         ENTRY;
 692
 693         rc = llog_handle2ops(loghandle, &lop);
 694         if (rc)
 695                 GOTO(out, rc);
 696         if (lop->lop_close == NULL)
 697                 GOTO(out, -EOPNOTSUPP);
 698         rc = lop->lop_close(env, loghandle);
 699 out:
 700         llog_free_handle(loghandle);
 701         RETURN(rc);
 702 }
 703 EXPORT_SYMBOL(llog_close);