kernel/drivers/staging/lustre/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  * Copyright (c) 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/obdclass/llog.c
  37  *
  38  * OST<->MDS recovery logging infrastructure.
  39  * Invariants in implementation:
  40  * - we do not share logs among different OST<->MDS connections, so that
  41  *   if an OST or MDS fails it need only look at log(s) relevant to itself
  42  *
  43  * Author: Andreas Dilger <adilger@clusterfs.com>
  44  * Author: Alex Zhuravlev <bzzz@whamcloud.com>
  45  * Author: Mikhail Pershin <tappro@whamcloud.com>
  46  */
  47
  48 #define DEBUG_SUBSYSTEM S_LOG
  49
  50
  51 #include "../include/obd_class.h"
  52 #include "../include/lustre_log.h"
  53 #include "llog_internal.h"
  54
  55 /*
  56  * Allocate a new log or catalog handle
  57  * Used inside llog_open().
  58  */
  59 static struct llog_handle *llog_alloc_handle(void)
  60 {
  61         struct llog_handle *loghandle;
  62
  63         OBD_ALLOC_PTR(loghandle);
  64         if (loghandle == NULL)
  65                 return NULL;
  66
  67         init_rwsem(&loghandle->lgh_lock);
  68         spin_lock_init(&loghandle->lgh_hdr_lock);
  69         INIT_LIST_HEAD(&loghandle->u.phd.phd_entry);
  70         atomic_set(&loghandle->lgh_refcount, 1);
  71
  72         return loghandle;
  73 }
  74
  75 /*
  76  * Free llog handle and header data if exists. Used in llog_close() only
  77  */
  78 static void llog_free_handle(struct llog_handle *loghandle)
  79 {
  80         LASSERT(loghandle != NULL);
  81
  82         /* failed llog_init_handle */
  83         if (!loghandle->lgh_hdr)
  84                 goto out;
  85
  86         if (loghandle->lgh_hdr->llh_flags & LLOG_F_IS_PLAIN)
  87                 LASSERT(list_empty(&loghandle->u.phd.phd_entry));
  88         else if (loghandle->lgh_hdr->llh_flags & LLOG_F_IS_CAT)
  89                 LASSERT(list_empty(&loghandle->u.chd.chd_head));
  90         LASSERT(sizeof(*(loghandle->lgh_hdr)) == LLOG_CHUNK_SIZE);
  91         OBD_FREE(loghandle->lgh_hdr, LLOG_CHUNK_SIZE);
  92 out:
  93         OBD_FREE_PTR(loghandle);
  94 }
  95
  96 void llog_handle_get(struct llog_handle *loghandle)
  97 {
  98         atomic_inc(&loghandle->lgh_refcount);
  99 }
 100
 101 void llog_handle_put(struct llog_handle *loghandle)
 102 {
 103         LASSERT(atomic_read(&loghandle->lgh_refcount) > 0);
 104         if (atomic_dec_and_test(&loghandle->lgh_refcount))
 105                 llog_free_handle(loghandle);
 106 }
 107
 108 /* returns negative on error; 0 if success; 1 if success & log destroyed */
 109 int llog_cancel_rec(const struct lu_env *env, struct llog_handle *loghandle,
 110                     int index)
 111 {
 112         struct llog_log_hdr *llh = loghandle->lgh_hdr;
 113         int rc = 0;
 114
 115         CDEBUG(D_RPCTRACE, "Canceling %d in log "DOSTID"\n",
 116                index, POSTID(&loghandle->lgh_id.lgl_oi));
 117
 118         if (index == 0) {
 119                 CERROR("Can't cancel index 0 which is header\n");
 120                 return -EINVAL;
 121         }
 122
 123         spin_lock(&loghandle->lgh_hdr_lock);
 124         if (!ext2_clear_bit(index, llh->llh_bitmap)) {
 125                 spin_unlock(&loghandle->lgh_hdr_lock);
 126                 CDEBUG(D_RPCTRACE, "Catalog index %u already clear?\n", index);
 127                 return -ENOENT;
 128         }
 129
 130         llh->llh_count--;
 131
 132         if ((llh->llh_flags & LLOG_F_ZAP_WHEN_EMPTY) &&
 133             (llh->llh_count == 1) &&
 134             (loghandle->lgh_last_idx == (LLOG_BITMAP_BYTES * 8) - 1)) {
 135                 spin_unlock(&loghandle->lgh_hdr_lock);
 136                 rc = llog_destroy(env, loghandle);
 137                 if (rc < 0) {
 138                         CERROR("%s: can't destroy empty llog #"DOSTID
 139                                "#%08x: rc = %d\n",
 140                                loghandle->lgh_ctxt->loc_obd->obd_name,
 141                                POSTID(&loghandle->lgh_id.lgl_oi),
 142                                loghandle->lgh_id.lgl_ogen, rc);
 143                         goto out_err;
 144                 }
 145                 return 1;
 146         }
 147         spin_unlock(&loghandle->lgh_hdr_lock);
 148
 149         rc = llog_write(env, loghandle, &llh->llh_hdr, NULL, 0, NULL, 0);
 150         if (rc < 0) {
 151                 CERROR("%s: fail to write header for llog #"DOSTID
 152                        "#%08x: rc = %d\n",
 153                        loghandle->lgh_ctxt->loc_obd->obd_name,
 154                        POSTID(&loghandle->lgh_id.lgl_oi),
 155                        loghandle->lgh_id.lgl_ogen, rc);
 156                 goto out_err;
 157         }
 158         return 0;
 159 out_err:
 160         spin_lock(&loghandle->lgh_hdr_lock);
 161         ext2_set_bit(index, llh->llh_bitmap);
 162         llh->llh_count++;
 163         spin_unlock(&loghandle->lgh_hdr_lock);
 164         return rc;
 165 }
 166 EXPORT_SYMBOL(llog_cancel_rec);
 167
 168 static int llog_read_header(const struct lu_env *env,
 169                             struct llog_handle *handle,
 170                             struct obd_uuid *uuid)
 171 {
 172         struct llog_operations *lop;
 173         int rc;
 174
 175         rc = llog_handle2ops(handle, &lop);
 176         if (rc)
 177                 return rc;
 178
 179         if (lop->lop_read_header == NULL)
 180                 return -EOPNOTSUPP;
 181
 182         rc = lop->lop_read_header(env, handle);
 183         if (rc == LLOG_EEMPTY) {
 184                 struct llog_log_hdr *llh = handle->lgh_hdr;
 185
 186                 handle->lgh_last_idx = 0; /* header is record with index 0 */
 187                 llh->llh_count = 1;      /* for the header record */
 188                 llh->llh_hdr.lrh_type = LLOG_HDR_MAGIC;
 189                 llh->llh_hdr.lrh_len = llh->llh_tail.lrt_len = LLOG_CHUNK_SIZE;
 190                 llh->llh_hdr.lrh_index = llh->llh_tail.lrt_index = 0;
 191                 llh->llh_timestamp = get_seconds();
 192                 if (uuid)
 193                         memcpy(&llh->llh_tgtuuid, uuid,
 194                                sizeof(llh->llh_tgtuuid));
 195                 llh->llh_bitmap_offset = offsetof(typeof(*llh), llh_bitmap);
 196                 ext2_set_bit(0, llh->llh_bitmap);
 197                 rc = 0;
 198         }
 199         return rc;
 200 }
 201
 202 int llog_init_handle(const struct lu_env *env, struct llog_handle *handle,
 203                      int flags, struct obd_uuid *uuid)
 204 {
 205         struct llog_log_hdr     *llh;
 206         int                      rc;
 207
 208         LASSERT(handle->lgh_hdr == NULL);
 209
 210         OBD_ALLOC_PTR(llh);
 211         if (llh == NULL)
 212                 return -ENOMEM;
 213         handle->lgh_hdr = llh;
 214         /* first assign flags to use llog_client_ops */
 215         llh->llh_flags = flags;
 216         rc = llog_read_header(env, handle, uuid);
 217         if (rc == 0) {
 218                 if (unlikely((llh->llh_flags & LLOG_F_IS_PLAIN &&
 219                               flags & LLOG_F_IS_CAT) ||
 220                              (llh->llh_flags & LLOG_F_IS_CAT &&
 221                               flags & LLOG_F_IS_PLAIN))) {
 222                         CERROR("%s: llog type is %s but initializing %s\n",
 223                                handle->lgh_ctxt->loc_obd->obd_name,
 224                                llh->llh_flags & LLOG_F_IS_CAT ?
 225                                "catalog" : "plain",
 226                                flags & LLOG_F_IS_CAT ? "catalog" : "plain");
 227                         rc = -EINVAL;
 228                         goto out;
 229                 } else if (llh->llh_flags &
 230                            (LLOG_F_IS_PLAIN | LLOG_F_IS_CAT)) {
 231                         /*
 232                          * it is possible to open llog without specifying llog
 233                          * type so it is taken from llh_flags
 234                          */
 235                         flags = llh->llh_flags;
 236                 } else {
 237                         /* for some reason the llh_flags has no type set */
 238                         CERROR("llog type is not specified!\n");
 239                         rc = -EINVAL;
 240                         goto out;
 241                 }
 242                 if (unlikely(uuid &&
 243                              !obd_uuid_equals(uuid, &llh->llh_tgtuuid))) {
 244                         CERROR("%s: llog uuid mismatch: %s/%s\n",
 245                                handle->lgh_ctxt->loc_obd->obd_name,
 246                                (char *)uuid->uuid,
 247                                (char *)llh->llh_tgtuuid.uuid);
 248                         rc = -EEXIST;
 249                         goto out;
 250                 }
 251         }
 252         if (flags & LLOG_F_IS_CAT) {
 253                 LASSERT(list_empty(&handle->u.chd.chd_head));
 254                 INIT_LIST_HEAD(&handle->u.chd.chd_head);
 255                 llh->llh_size = sizeof(struct llog_logid_rec);
 256         } else if (!(flags & LLOG_F_IS_PLAIN)) {
 257                 CERROR("%s: unknown flags: %#x (expected %#x or %#x)\n",
 258                        handle->lgh_ctxt->loc_obd->obd_name,
 259                        flags, LLOG_F_IS_CAT, LLOG_F_IS_PLAIN);
 260                 rc = -EINVAL;
 261         }
 262 out:
 263         if (rc) {
 264                 OBD_FREE_PTR(llh);
 265                 handle->lgh_hdr = NULL;
 266         }
 267         return rc;
 268 }
 269 EXPORT_SYMBOL(llog_init_handle);
 270
 271 static int llog_process_thread(void *arg)
 272 {
 273         struct llog_process_info        *lpi = arg;
 274         struct llog_handle              *loghandle = lpi->lpi_loghandle;
 275         struct llog_log_hdr             *llh = loghandle->lgh_hdr;
 276         struct llog_process_cat_data    *cd  = lpi->lpi_catdata;
 277         char                            *buf;
 278         __u64                            cur_offset = LLOG_CHUNK_SIZE;
 279         __u64                            last_offset;
 280         int                              rc = 0, index = 1, last_index;
 281         int                              saved_index = 0;
 282         int                              last_called_index = 0;
 283
 284         LASSERT(llh);
 285
 286         OBD_ALLOC(buf, LLOG_CHUNK_SIZE);
 287         if (!buf) {
 288                 lpi->lpi_rc = -ENOMEM;
 289                 return 0;
 290         }
 291
 292         if (cd != NULL) {
 293                 last_called_index = cd->lpcd_first_idx;
 294                 index = cd->lpcd_first_idx + 1;
 295         }
 296         if (cd != NULL && cd->lpcd_last_idx)
 297                 last_index = cd->lpcd_last_idx;
 298         else
 299                 last_index = LLOG_BITMAP_BYTES * 8 - 1;
 300
 301         while (rc == 0) {
 302                 struct llog_rec_hdr *rec;
 303
 304                 /* skip records not set in bitmap */
 305                 while (index <= last_index &&
 306                        !ext2_test_bit(index, llh->llh_bitmap))
 307                         ++index;
 308
 309                 LASSERT(index <= last_index + 1);
 310                 if (index == last_index + 1)
 311                         break;
 312 repeat:
 313                 CDEBUG(D_OTHER, "index: %d last_index %d\n",
 314                        index, last_index);
 315
 316                 /* get the buf with our target record; avoid old garbage */
 317                 memset(buf, 0, LLOG_CHUNK_SIZE);
 318                 last_offset = cur_offset;
 319                 rc = llog_next_block(lpi->lpi_env, loghandle, &saved_index,
 320                                      index, &cur_offset, buf, LLOG_CHUNK_SIZE);
 321                 if (rc)
 322                         goto out;
 323
 324                 /* NB: when rec->lrh_len is accessed it is already swabbed
 325                  * since it is used at the "end" of the loop and the rec
 326                  * swabbing is done at the beginning of the loop. */
 327                 for (rec = (struct llog_rec_hdr *)buf;
 328                      (char *)rec < buf + LLOG_CHUNK_SIZE;
 329                      rec = (struct llog_rec_hdr *)((char *)rec + rec->lrh_len)){
 330
 331                         CDEBUG(D_OTHER, "processing rec 0x%p type %#x\n",
 332                                rec, rec->lrh_type);
 333
 334                         if (LLOG_REC_HDR_NEEDS_SWABBING(rec))
 335                                 lustre_swab_llog_rec(rec);
 336
 337                         CDEBUG(D_OTHER, "after swabbing, type=%#x idx=%d\n",
 338                                rec->lrh_type, rec->lrh_index);
 339
 340                         if (rec->lrh_index == 0) {
 341                                 /* probably another rec just got added? */
 342                                 rc = 0;
 343                                 if (index <= loghandle->lgh_last_idx)
 344                                         goto repeat;
 345                                 goto out; /* no more records */
 346                         }
 347                         if (rec->lrh_len == 0 ||
 348                             rec->lrh_len > LLOG_CHUNK_SIZE) {
 349                                 CWARN("invalid length %d in llog record for index %d/%d\n",
 350                                       rec->lrh_len,
 351                                       rec->lrh_index, index);
 352                                 rc = -EINVAL;
 353                                 goto out;
 354                         }
 355
 356                         if (rec->lrh_index < index) {
 357                                 CDEBUG(D_OTHER, "skipping lrh_index %d\n",
 358                                        rec->lrh_index);
 359                                 continue;
 360                         }
 361
 362                         CDEBUG(D_OTHER,
 363                                "lrh_index: %d lrh_len: %d (%d remains)\n",
 364                                rec->lrh_index, rec->lrh_len,
 365                                (int)(buf + LLOG_CHUNK_SIZE - (char *)rec));
 366
 367                         loghandle->lgh_cur_idx = rec->lrh_index;
 368                         loghandle->lgh_cur_offset = (char *)rec - (char *)buf +
 369                                                     last_offset;
 370
 371                         /* if set, process the callback on this record */
 372                         if (ext2_test_bit(index, llh->llh_bitmap)) {
 373                                 rc = lpi->lpi_cb(lpi->lpi_env, loghandle, rec,
 374                                                  lpi->lpi_cbdata);
 375                                 last_called_index = index;
 376                                 if (rc == LLOG_PROC_BREAK) {
 377                                         goto out;
 378                                 } else if (rc == LLOG_DEL_RECORD) {
 379                                         llog_cancel_rec(lpi->lpi_env,
 380                                                         loghandle,
 381                                                         rec->lrh_index);
 382                                         rc = 0;
 383                                 }
 384                                 if (rc)
 385                                         goto out;
 386                         } else {
 387                                 CDEBUG(D_OTHER, "Skipped index %d\n", index);
 388                         }
 389
 390                         /* next record, still in buffer? */
 391                         ++index;
 392                         if (index > last_index) {
 393                                 rc = 0;
 394                                 goto out;
 395                         }
 396                 }
 397         }
 398
 399 out:
 400         if (cd != NULL)
 401                 cd->lpcd_last_idx = last_called_index;
 402
 403         OBD_FREE(buf, LLOG_CHUNK_SIZE);
 404         lpi->lpi_rc = rc;
 405         return 0;
 406 }
 407
 408 static int llog_process_thread_daemonize(void *arg)
 409 {
 410         struct llog_process_info        *lpi = arg;
 411         struct lu_env                    env;
 412         int                              rc;
 413
 414         unshare_fs_struct();
 415
 416         /* client env has no keys, tags is just 0 */
 417         rc = lu_env_init(&env, LCT_LOCAL | LCT_MG_THREAD);
 418         if (rc)
 419                 goto out;
 420         lpi->lpi_env = &env;
 421
 422         rc = llog_process_thread(arg);
 423
 424         lu_env_fini(&env);
 425 out:
 426         complete(&lpi->lpi_completion);
 427         return rc;
 428 }
 429
 430 int llog_process_or_fork(const struct lu_env *env,
 431                          struct llog_handle *loghandle,
 432                          llog_cb_t cb, void *data, void *catdata, bool fork)
 433 {
 434         struct llog_process_info *lpi;
 435         int                   rc;
 436
 437         OBD_ALLOC_PTR(lpi);
 438         if (lpi == NULL) {
 439                 CERROR("cannot alloc pointer\n");
 440                 return -ENOMEM;
 441         }
 442         lpi->lpi_loghandle = loghandle;
 443         lpi->lpi_cb     = cb;
 444         lpi->lpi_cbdata    = data;
 445         lpi->lpi_catdata   = catdata;
 446
 447         if (fork) {
 448                 /* The new thread can't use parent env,
 449                  * init the new one in llog_process_thread_daemonize. */
 450                 lpi->lpi_env = NULL;
 451                 init_completion(&lpi->lpi_completion);
 452                 rc = PTR_ERR(kthread_run(llog_process_thread_daemonize, lpi,
 453                                              "llog_process_thread"));
 454                 if (IS_ERR_VALUE(rc)) {
 455                         CERROR("%s: cannot start thread: rc = %d\n",
 456                                loghandle->lgh_ctxt->loc_obd->obd_name, rc);
 457                         OBD_FREE_PTR(lpi);
 458                         return rc;
 459                 }
 460                 wait_for_completion(&lpi->lpi_completion);
 461         } else {
 462                 lpi->lpi_env = env;
 463                 llog_process_thread(lpi);
 464         }
 465         rc = lpi->lpi_rc;
 466         OBD_FREE_PTR(lpi);
 467         return rc;
 468 }
 469 EXPORT_SYMBOL(llog_process_or_fork);
 470
 471 int llog_process(const struct lu_env *env, struct llog_handle *loghandle,
 472                  llog_cb_t cb, void *data, void *catdata)
 473 {
 474         return llog_process_or_fork(env, loghandle, cb, data, catdata, true);
 475 }
 476 EXPORT_SYMBOL(llog_process);
 477
 478 int llog_reverse_process(const struct lu_env *env,
 479                          struct llog_handle *loghandle, llog_cb_t cb,
 480                          void *data, void *catdata)
 481 {
 482         struct llog_log_hdr *llh = loghandle->lgh_hdr;
 483         struct llog_process_cat_data *cd = catdata;
 484         void *buf;
 485         int rc = 0, first_index = 1, index, idx;
 486
 487         OBD_ALLOC(buf, LLOG_CHUNK_SIZE);
 488         if (!buf)
 489                 return -ENOMEM;
 490
 491         if (cd != NULL)
 492                 first_index = cd->lpcd_first_idx + 1;
 493         if (cd != NULL && cd->lpcd_last_idx)
 494                 index = cd->lpcd_last_idx;
 495         else
 496                 index = LLOG_BITMAP_BYTES * 8 - 1;
 497
 498         while (rc == 0) {
 499                 struct llog_rec_hdr *rec;
 500                 struct llog_rec_tail *tail;
 501
 502                 /* skip records not set in bitmap */
 503                 while (index >= first_index &&
 504                        !ext2_test_bit(index, llh->llh_bitmap))
 505                         --index;
 506
 507                 LASSERT(index >= first_index - 1);
 508                 if (index == first_index - 1)
 509                         break;
 510
 511                 /* get the buf with our target record; avoid old garbage */
 512                 memset(buf, 0, LLOG_CHUNK_SIZE);
 513                 rc = llog_prev_block(env, loghandle, index, buf,
 514                                      LLOG_CHUNK_SIZE);
 515                 if (rc)
 516                         goto out;
 517
 518                 rec = buf;
 519                 idx = rec->lrh_index;
 520                 CDEBUG(D_RPCTRACE, "index %u : idx %u\n", index, idx);
 521                 while (idx < index) {
 522                         rec = (void *)rec + rec->lrh_len;
 523                         if (LLOG_REC_HDR_NEEDS_SWABBING(rec))
 524                                 lustre_swab_llog_rec(rec);
 525                         idx ++;
 526                 }
 527                 LASSERT(idx == index);
 528                 tail = (void *)rec + rec->lrh_len - sizeof(*tail);
 529
 530                 /* process records in buffer, starting where we found one */
 531                 while ((void *)tail > buf) {
 532                         if (tail->lrt_index == 0) {
 533                                 /* no more records */
 534                                 rc = 0;
 535                                 goto out;
 536                         }
 537
 538                         /* if set, process the callback on this record */
 539                         if (ext2_test_bit(index, llh->llh_bitmap)) {
 540                                 rec = (void *)tail - tail->lrt_len +
 541                                       sizeof(*tail);
 542
 543                                 rc = cb(env, loghandle, rec, data);
 544                                 if (rc == LLOG_PROC_BREAK) {
 545                                         goto out;
 546                                 } else if (rc == LLOG_DEL_RECORD) {
 547                                         llog_cancel_rec(env, loghandle,
 548                                                         tail->lrt_index);
 549                                         rc = 0;
 550                                 }
 551                                 if (rc)
 552                                         goto out;
 553                         }
 554
 555                         /* previous record, still in buffer? */
 556                         --index;
 557                         if (index < first_index) {
 558                                 rc = 0;
 559                                 goto out;
 560                         }
 561                         tail = (void *)tail - tail->lrt_len;
 562                 }
 563         }
 564
 565 out:
 566         if (buf)
 567                 OBD_FREE(buf, LLOG_CHUNK_SIZE);
 568         return rc;
 569 }
 570 EXPORT_SYMBOL(llog_reverse_process);
 571
 572 /**
 573  * new llog API
 574  *
 575  * API functions:
 576  *      llog_open - open llog, may not exist
 577  *      llog_exist - check if llog exists
 578  *      llog_close - close opened llog, pair for open, frees llog_handle
 579  *      llog_declare_create - declare llog creation
 580  *      llog_create - create new llog on disk, need transaction handle
 581  *      llog_declare_write_rec - declaration of llog write
 582  *      llog_write_rec - write llog record on disk, need transaction handle
 583  *      llog_declare_add - declare llog catalog record addition
 584  *      llog_add - add llog record in catalog, need transaction handle
 585  */
 586 int llog_exist(struct llog_handle *loghandle)
 587 {
 588         struct llog_operations  *lop;
 589         int                      rc;
 590
 591         rc = llog_handle2ops(loghandle, &lop);
 592         if (rc)
 593                 return rc;
 594         if (lop->lop_exist == NULL)
 595                 return -EOPNOTSUPP;
 596
 597         rc = lop->lop_exist(loghandle);
 598         return rc;
 599 }
 600 EXPORT_SYMBOL(llog_exist);
 601
 602 int llog_declare_create(const struct lu_env *env,
 603                         struct llog_handle *loghandle, struct thandle *th)
 604 {
 605         struct llog_operations  *lop;
 606         int                      raised, rc;
 607
 608         rc = llog_handle2ops(loghandle, &lop);
 609         if (rc)
 610                 return rc;
 611         if (lop->lop_declare_create == NULL)
 612                 return -EOPNOTSUPP;
 613
 614         raised = cfs_cap_raised(CFS_CAP_SYS_RESOURCE);
 615         if (!raised)
 616                 cfs_cap_raise(CFS_CAP_SYS_RESOURCE);
 617         rc = lop->lop_declare_create(env, loghandle, th);
 618         if (!raised)
 619                 cfs_cap_lower(CFS_CAP_SYS_RESOURCE);
 620         return rc;
 621 }
 622 EXPORT_SYMBOL(llog_declare_create);
 623
 624 int llog_create(const struct lu_env *env, struct llog_handle *handle,
 625                 struct thandle *th)
 626 {
 627         struct llog_operations  *lop;
 628         int                      raised, rc;
 629
 630         rc = llog_handle2ops(handle, &lop);
 631         if (rc)
 632                 return rc;
 633         if (lop->lop_create == NULL)
 634                 return -EOPNOTSUPP;
 635
 636         raised = cfs_cap_raised(CFS_CAP_SYS_RESOURCE);
 637         if (!raised)
 638                 cfs_cap_raise(CFS_CAP_SYS_RESOURCE);
 639         rc = lop->lop_create(env, handle, th);
 640         if (!raised)
 641                 cfs_cap_lower(CFS_CAP_SYS_RESOURCE);
 642         return rc;
 643 }
 644 EXPORT_SYMBOL(llog_create);
 645
 646 int llog_declare_write_rec(const struct lu_env *env,
 647                            struct llog_handle *handle,
 648                            struct llog_rec_hdr *rec, int idx,
 649                            struct thandle *th)
 650 {
 651         struct llog_operations  *lop;
 652         int                      raised, rc;
 653
 654         rc = llog_handle2ops(handle, &lop);
 655         if (rc)
 656                 return rc;
 657         LASSERT(lop);
 658         if (lop->lop_declare_write_rec == NULL)
 659                 return -EOPNOTSUPP;
 660
 661         raised = cfs_cap_raised(CFS_CAP_SYS_RESOURCE);
 662         if (!raised)
 663                 cfs_cap_raise(CFS_CAP_SYS_RESOURCE);
 664         rc = lop->lop_declare_write_rec(env, handle, rec, idx, th);
 665         if (!raised)
 666                 cfs_cap_lower(CFS_CAP_SYS_RESOURCE);
 667         return rc;
 668 }
 669 EXPORT_SYMBOL(llog_declare_write_rec);
 670
 671 int llog_write_rec(const struct lu_env *env, struct llog_handle *handle,
 672                    struct llog_rec_hdr *rec, struct llog_cookie *logcookies,
 673                    int numcookies, void *buf, int idx, struct thandle *th)
 674 {
 675         struct llog_operations  *lop;
 676         int                      raised, rc, buflen;
 677
 678         rc = llog_handle2ops(handle, &lop);
 679         if (rc)
 680                 return rc;
 681
 682         LASSERT(lop);
 683         if (lop->lop_write_rec == NULL)
 684                 return -EOPNOTSUPP;
 685
 686         if (buf)
 687                 buflen = rec->lrh_len + sizeof(struct llog_rec_hdr) +
 688                          sizeof(struct llog_rec_tail);
 689         else
 690                 buflen = rec->lrh_len;
 691         LASSERT(cfs_size_round(buflen) == buflen);
 692
 693         raised = cfs_cap_raised(CFS_CAP_SYS_RESOURCE);
 694         if (!raised)
 695                 cfs_cap_raise(CFS_CAP_SYS_RESOURCE);
 696         rc = lop->lop_write_rec(env, handle, rec, logcookies, numcookies,
 697                                 buf, idx, th);
 698         if (!raised)
 699                 cfs_cap_lower(CFS_CAP_SYS_RESOURCE);
 700         return rc;
 701 }
 702 EXPORT_SYMBOL(llog_write_rec);
 703
 704 int llog_add(const struct lu_env *env, struct llog_handle *lgh,
 705              struct llog_rec_hdr *rec, struct llog_cookie *logcookies,
 706              void *buf, struct thandle *th)
 707 {
 708         int raised, rc;
 709
 710         if (lgh->lgh_logops->lop_add == NULL)
 711                 return -EOPNOTSUPP;
 712
 713         raised = cfs_cap_raised(CFS_CAP_SYS_RESOURCE);
 714         if (!raised)
 715                 cfs_cap_raise(CFS_CAP_SYS_RESOURCE);
 716         rc = lgh->lgh_logops->lop_add(env, lgh, rec, logcookies, buf, th);
 717         if (!raised)
 718                 cfs_cap_lower(CFS_CAP_SYS_RESOURCE);
 719         return rc;
 720 }
 721 EXPORT_SYMBOL(llog_add);
 722
 723 int llog_declare_add(const struct lu_env *env, struct llog_handle *lgh,
 724                      struct llog_rec_hdr *rec, struct thandle *th)
 725 {
 726         int raised, rc;
 727
 728         if (lgh->lgh_logops->lop_declare_add == NULL)
 729                 return -EOPNOTSUPP;
 730
 731         raised = cfs_cap_raised(CFS_CAP_SYS_RESOURCE);
 732         if (!raised)
 733                 cfs_cap_raise(CFS_CAP_SYS_RESOURCE);
 734         rc = lgh->lgh_logops->lop_declare_add(env, lgh, rec, th);
 735         if (!raised)
 736                 cfs_cap_lower(CFS_CAP_SYS_RESOURCE);
 737         return rc;
 738 }
 739 EXPORT_SYMBOL(llog_declare_add);
 740
 741 /**
 742  * Helper function to open llog or create it if doesn't exist.
 743  * It hides all transaction handling from caller.
 744  */
 745 int llog_open_create(const struct lu_env *env, struct llog_ctxt *ctxt,
 746                      struct llog_handle **res, struct llog_logid *logid,
 747                      char *name)
 748 {
 749         struct dt_device        *d;
 750         struct thandle          *th;
 751         int                      rc;
 752
 753         rc = llog_open(env, ctxt, res, logid, name, LLOG_OPEN_NEW);
 754         if (rc)
 755                 return rc;
 756
 757         if (llog_exist(*res))
 758                 return 0;
 759
 760         LASSERT((*res)->lgh_obj != NULL);
 761
 762         d = lu2dt_dev((*res)->lgh_obj->do_lu.lo_dev);
 763
 764         th = dt_trans_create(env, d);
 765         if (IS_ERR(th)) {
 766                 rc = PTR_ERR(th);
 767                 goto out;
 768         }
 769
 770         rc = llog_declare_create(env, *res, th);
 771         if (rc == 0) {
 772                 rc = dt_trans_start_local(env, d, th);
 773                 if (rc == 0)
 774                         rc = llog_create(env, *res, th);
 775         }
 776         dt_trans_stop(env, d, th);
 777 out:
 778         if (rc)
 779                 llog_close(env, *res);
 780         return rc;
 781 }
 782 EXPORT_SYMBOL(llog_open_create);
 783
 784 /**
 785  * Helper function to delete existent llog.
 786  */
 787 int llog_erase(const struct lu_env *env, struct llog_ctxt *ctxt,
 788                struct llog_logid *logid, char *name)
 789 {
 790         struct llog_handle      *handle;
 791         int                      rc = 0, rc2;
 792
 793         /* nothing to erase */
 794         if (name == NULL && logid == NULL)
 795                 return 0;
 796
 797         rc = llog_open(env, ctxt, &handle, logid, name, LLOG_OPEN_EXISTS);
 798         if (rc < 0)
 799                 return rc;
 800
 801         rc = llog_init_handle(env, handle, LLOG_F_IS_PLAIN, NULL);
 802         if (rc == 0)
 803                 rc = llog_destroy(env, handle);
 804
 805         rc2 = llog_close(env, handle);
 806         if (rc == 0)
 807                 rc = rc2;
 808         return rc;
 809 }
 810 EXPORT_SYMBOL(llog_erase);
 811
 812 /*
 813  * Helper function for write record in llog.
 814  * It hides all transaction handling from caller.
 815  * Valid only with local llog.
 816  */
 817 int llog_write(const struct lu_env *env, struct llog_handle *loghandle,
 818                struct llog_rec_hdr *rec, struct llog_cookie *reccookie,
 819                int cookiecount, void *buf, int idx)
 820 {
 821         struct dt_device        *dt;
 822         struct thandle          *th;
 823         int                      rc;
 824
 825         LASSERT(loghandle);
 826         LASSERT(loghandle->lgh_ctxt);
 827         LASSERT(loghandle->lgh_obj != NULL);
 828
 829         dt = lu2dt_dev(loghandle->lgh_obj->do_lu.lo_dev);
 830
 831         th = dt_trans_create(env, dt);
 832         if (IS_ERR(th))
 833                 return PTR_ERR(th);
 834
 835         rc = llog_declare_write_rec(env, loghandle, rec, idx, th);
 836         if (rc)
 837                 goto out_trans;
 838
 839         rc = dt_trans_start_local(env, dt, th);
 840         if (rc)
 841                 goto out_trans;
 842
 843         down_write(&loghandle->lgh_lock);
 844         rc = llog_write_rec(env, loghandle, rec, reccookie,
 845                             cookiecount, buf, idx, th);
 846         up_write(&loghandle->lgh_lock);
 847 out_trans:
 848         dt_trans_stop(env, dt, th);
 849         return rc;
 850 }
 851 EXPORT_SYMBOL(llog_write);
 852
 853 int llog_open(const struct lu_env *env, struct llog_ctxt *ctxt,
 854               struct llog_handle **lgh, struct llog_logid *logid,
 855               char *name, enum llog_open_param open_param)
 856 {
 857         int      raised;
 858         int      rc;
 859
 860         LASSERT(ctxt);
 861         LASSERT(ctxt->loc_logops);
 862
 863         if (ctxt->loc_logops->lop_open == NULL) {
 864                 *lgh = NULL;
 865                 return -EOPNOTSUPP;
 866         }
 867
 868         *lgh = llog_alloc_handle();
 869         if (*lgh == NULL)
 870                 return -ENOMEM;
 871         (*lgh)->lgh_ctxt = ctxt;
 872         (*lgh)->lgh_logops = ctxt->loc_logops;
 873
 874         raised = cfs_cap_raised(CFS_CAP_SYS_RESOURCE);
 875         if (!raised)
 876                 cfs_cap_raise(CFS_CAP_SYS_RESOURCE);
 877         rc = ctxt->loc_logops->lop_open(env, *lgh, logid, name, open_param);
 878         if (!raised)
 879                 cfs_cap_lower(CFS_CAP_SYS_RESOURCE);
 880         if (rc) {
 881                 llog_free_handle(*lgh);
 882                 *lgh = NULL;
 883         }
 884         return rc;
 885 }
 886 EXPORT_SYMBOL(llog_open);
 887
 888 int llog_close(const struct lu_env *env, struct llog_handle *loghandle)
 889 {
 890         struct llog_operations  *lop;
 891         int                      rc;
 892
 893         rc = llog_handle2ops(loghandle, &lop);
 894         if (rc)
 895                 goto out;
 896         if (lop->lop_close == NULL) {
 897                 rc = -EOPNOTSUPP;
 898                 goto out;
 899         }
 900         rc = lop->lop_close(env, loghandle);
 901 out:
 902         llog_handle_put(loghandle);
 903         return rc;
 904 }
 905 EXPORT_SYMBOL(llog_close);
 906
 907 int llog_is_empty(const struct lu_env *env, struct llog_ctxt *ctxt,
 908                   char *name)
 909 {
 910         struct llog_handle      *llh;
 911         int                      rc = 0;
 912
 913         rc = llog_open(env, ctxt, &llh, NULL, name, LLOG_OPEN_EXISTS);
 914         if (rc < 0) {
 915                 if (likely(rc == -ENOENT))
 916                         rc = 0;
 917                 goto out;
 918         }
 919
 920         rc = llog_init_handle(env, llh, LLOG_F_IS_PLAIN, NULL);
 921         if (rc)
 922                 goto out_close;
 923         rc = llog_get_size(llh);
 924
 925 out_close:
 926         llog_close(env, llh);
 927 out:
 928         /* header is record 1 */
 929         return rc <= 1;
 930 }
 931 EXPORT_SYMBOL(llog_is_empty);
 932
 933 int llog_copy_handler(const struct lu_env *env, struct llog_handle *llh,
 934                       struct llog_rec_hdr *rec, void *data)
 935 {
 936         struct llog_handle      *copy_llh = data;
 937
 938         /* Append all records */
 939         return llog_write(env, copy_llh, rec, NULL, 0, NULL, -1);
 940 }
 941 EXPORT_SYMBOL(llog_copy_handler);
 942
 943 /* backup plain llog */
 944 int llog_backup(const struct lu_env *env, struct obd_device *obd,
 945                 struct llog_ctxt *ctxt, struct llog_ctxt *bctxt,
 946                 char *name, char *backup)
 947 {
 948         struct llog_handle      *llh, *bllh;
 949         int                      rc;
 950
 951
 952
 953         /* open original log */
 954         rc = llog_open(env, ctxt, &llh, NULL, name, LLOG_OPEN_EXISTS);
 955         if (rc < 0) {
 956                 /* the -ENOENT case is also reported to the caller
 957                  * but silently so it should handle that if needed.
 958                  */
 959                 if (rc != -ENOENT)
 960                         CERROR("%s: failed to open log %s: rc = %d\n",
 961                                obd->obd_name, name, rc);
 962                 return rc;
 963         }
 964
 965         rc = llog_init_handle(env, llh, LLOG_F_IS_PLAIN, NULL);
 966         if (rc)
 967                 goto out_close;
 968
 969         /* Make sure there's no old backup log */
 970         rc = llog_erase(env, bctxt, NULL, backup);
 971         if (rc < 0 && rc != -ENOENT)
 972                 goto out_close;
 973
 974         /* open backup log */
 975         rc = llog_open_create(env, bctxt, &bllh, NULL, backup);
 976         if (rc) {
 977                 CERROR("%s: failed to open backup logfile %s: rc = %d\n",
 978                        obd->obd_name, backup, rc);
 979                 goto out_close;
 980         }
 981
 982         /* check that backup llog is not the same object as original one */
 983         if (llh->lgh_obj == bllh->lgh_obj) {
 984                 CERROR("%s: backup llog %s to itself (%s), objects %p/%p\n",
 985                        obd->obd_name, name, backup, llh->lgh_obj,
 986                        bllh->lgh_obj);
 987                 rc = -EEXIST;
 988                 goto out_backup;
 989         }
 990
 991         rc = llog_init_handle(env, bllh, LLOG_F_IS_PLAIN, NULL);
 992         if (rc)
 993                 goto out_backup;
 994
 995         /* Copy log record by record */
 996         rc = llog_process_or_fork(env, llh, llog_copy_handler, (void *)bllh,
 997                                   NULL, false);
 998         if (rc)
 999                 CERROR("%s: failed to backup log %s: rc = %d\n",
1000                        obd->obd_name, name, rc);
1001 out_backup:
1002         llog_close(env, bllh);
1003 out_close:
1004         llog_close(env, llh);
1005         return rc;
1006 }
1007 EXPORT_SYMBOL(llog_backup);