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.gnu.org/licenses/gpl-2.0.html
  19  *
  20  * GPL HEADER END
  21  */
  22 /*
  23  * Copyright (c) 2003, 2010, Oracle and/or its affiliates. All rights reserved.
  24  * Use is subject to license terms.
  25  *
  26  * Copyright (c) 2012, 2017, Intel Corporation.
  27  */
  28 /*
  29  * This file is part of Lustre, http://www.lustre.org/
  30  * Lustre is a trademark of Sun Microsystems, Inc.
  31  *
  32  * lustre/obdclass/llog.c
  33  *
  34  * OST<->MDS recovery logging infrastructure.
  35  * Invariants in implementation:
  36  * - we do not share logs among different OST<->MDS connections, so that
  37  *   if an OST or MDS fails it need only look at log(s) relevant to itself
  38  *
  39  * Author: Andreas Dilger <adilger@clusterfs.com>
  40  * Author: Alex Zhuravlev <bzzz@whamcloud.com>
  41  * Author: Mikhail Pershin <tappro@whamcloud.com>
  42  */
  43
  44 #define DEBUG_SUBSYSTEM S_LOG
  45
  46 #include <linux/pid_namespace.h>
  47 #include <linux/kthread.h>
  48 #include <llog_swab.h>
  49 #include <lustre_log.h>
  50 #include <obd_support.h>
  51 #include <obd_class.h>
  52 #include "llog_internal.h"
  53 /*
  54  * Allocate a new log or catalog handle
  55  * Used inside llog_open().
  56  */
  57 static struct llog_handle *llog_alloc_handle(void)
  58 {
  59         struct llog_handle *loghandle;
  60
  61         OBD_ALLOC_PTR(loghandle);
  62         if (loghandle == NULL)
  63                 return NULL;
  64
  65         init_rwsem(&loghandle->lgh_lock);
  66         mutex_init(&loghandle->lgh_hdr_mutex);
  67         init_rwsem(&loghandle->lgh_last_sem);
  68         INIT_LIST_HEAD(&loghandle->u.phd.phd_entry);
  69         refcount_set(&loghandle->lgh_refcount, 1);
  70
  71         return loghandle;
  72 }
  73
  74 /*
  75  * Free llog handle and header data if exists. Used in llog_close() only
  76  */
  77 static void llog_free_handle(struct llog_handle *loghandle)
  78 {
  79         LASSERT(loghandle != NULL);
  80
  81         /* failed llog_init_handle */
  82         if (loghandle->lgh_hdr == NULL)
  83                 goto out;
  84
  85         if (loghandle->lgh_hdr->llh_flags & LLOG_F_IS_PLAIN)
  86                 LASSERT(list_empty(&loghandle->u.phd.phd_entry));
  87         else if (loghandle->lgh_hdr->llh_flags & LLOG_F_IS_CAT)
  88                 LASSERT(list_empty(&loghandle->u.chd.chd_head));
  89         OBD_FREE_LARGE(loghandle->lgh_hdr, loghandle->lgh_hdr_size);
  90 out:
  91         OBD_FREE_PTR(loghandle);
  92 }
  93
  94 struct llog_handle *llog_handle_get(struct llog_handle *loghandle)
  95 {
  96         if (refcount_inc_not_zero(&loghandle->lgh_refcount))
  97                 return loghandle;
  98         return NULL;
  99 }
 100
 101 int llog_handle_put(const struct lu_env *env, struct llog_handle *loghandle)
 102 {
 103         int rc = 0;
 104
 105         if (refcount_dec_and_test(&loghandle->lgh_refcount)) {
 106                 struct llog_operations *lop;
 107
 108                 rc = llog_handle2ops(loghandle, &lop);
 109                 if (!rc) {
 110                         if (lop->lop_close)
 111                                 rc = lop->lop_close(env, loghandle);
 112                         else
 113                                 rc = -EOPNOTSUPP;
 114                 }
 115                 llog_free_handle(loghandle);
 116         }
 117         return rc;
 118 }
 119
 120 static int llog_declare_destroy(const struct lu_env *env,
 121                                 struct llog_handle *handle,
 122                                 struct thandle *th)
 123 {
 124         struct llog_operations *lop;
 125         int rc;
 126
 127         ENTRY;
 128
 129         rc = llog_handle2ops(handle, &lop);
 130         if (rc)
 131                 RETURN(rc);
 132         if (lop->lop_declare_destroy == NULL)
 133                 RETURN(-EOPNOTSUPP);
 134
 135         rc = lop->lop_declare_destroy(env, handle, th);
 136
 137         RETURN(rc);
 138 }
 139
 140 int llog_trans_destroy(const struct lu_env *env, struct llog_handle *handle,
 141                        struct thandle *th)
 142 {
 143         struct llog_operations  *lop;
 144         int rc;
 145         ENTRY;
 146
 147         rc = llog_handle2ops(handle, &lop);
 148         if (rc < 0)
 149                 RETURN(rc);
 150         if (lop->lop_destroy == NULL)
 151                 RETURN(-EOPNOTSUPP);
 152
 153         LASSERT(handle->lgh_obj != NULL);
 154         if (!llog_exist(handle))
 155                 RETURN(0);
 156
 157         rc = lop->lop_destroy(env, handle, th);
 158
 159         RETURN(rc);
 160 }
 161
 162 int llog_destroy(const struct lu_env *env, struct llog_handle *handle)
 163 {
 164         struct llog_operations  *lop;
 165         struct dt_device        *dt;
 166         struct thandle          *th;
 167         int rc;
 168
 169         ENTRY;
 170
 171         rc = llog_handle2ops(handle, &lop);
 172         if (rc < 0)
 173                 RETURN(rc);
 174         if (lop->lop_destroy == NULL)
 175                 RETURN(-EOPNOTSUPP);
 176
 177         if (handle->lgh_obj == NULL) {
 178                 /* if lgh_obj == NULL, then it is from client side destroy */
 179                 rc = lop->lop_destroy(env, handle, NULL);
 180                 RETURN(rc);
 181         }
 182
 183         if (!llog_exist(handle))
 184                 RETURN(0);
 185
 186         dt = lu2dt_dev(handle->lgh_obj->do_lu.lo_dev);
 187
 188         if (unlikely(unlikely(dt->dd_rdonly)))
 189                 RETURN(-EROFS);
 190
 191         th = dt_trans_create(env, dt);
 192         if (IS_ERR(th))
 193                 RETURN(PTR_ERR(th));
 194
 195         rc = llog_declare_destroy(env, handle, th);
 196         if (rc != 0)
 197                 GOTO(out_trans, rc);
 198
 199         rc = dt_trans_start_local(env, dt, th);
 200         if (rc < 0)
 201                 GOTO(out_trans, rc);
 202
 203         rc = lop->lop_destroy(env, handle, th);
 204
 205 out_trans:
 206         dt_trans_stop(env, dt, th);
 207
 208         RETURN(rc);
 209 }
 210 EXPORT_SYMBOL(llog_destroy);
 211
 212 /* returns negative on error; 0 if success; 1 if success & log destroyed */
 213 int llog_cancel_arr_rec(const struct lu_env *env, struct llog_handle *loghandle,
 214                         int num, int *index)
 215 {
 216         struct llog_thread_info *lgi = llog_info(env);
 217         struct dt_device        *dt;
 218         struct llog_log_hdr     *llh;
 219         struct thandle          *th;
 220         __u32                    tmp_lgc_index;
 221         int                      rc, i = 0;
 222         int rc1;
 223         bool subtract_count = false;
 224
 225         ENTRY;
 226
 227         LASSERT(loghandle != NULL);
 228         LASSERT(loghandle->lgh_ctxt != NULL);
 229         LASSERT(loghandle->lgh_obj != NULL);
 230
 231         llh = loghandle->lgh_hdr;
 232
 233         CDEBUG(D_RPCTRACE, "Canceling %d records, first %d in log "DFID"\n",
 234                num, index[0], PFID(&loghandle->lgh_id.lgl_oi.oi_fid));
 235
 236         dt = lu2dt_dev(loghandle->lgh_obj->do_lu.lo_dev);
 237
 238         if (unlikely(unlikely(dt->dd_rdonly)))
 239                 RETURN(0);
 240
 241         th = dt_trans_create(env, dt);
 242         if (IS_ERR(th))
 243                 RETURN(PTR_ERR(th));
 244
 245         rc = llog_declare_write_rec(env, loghandle, &llh->llh_hdr, 0, th);
 246         if (rc < 0)
 247                 GOTO(out_trans, rc);
 248
 249         if ((llh->llh_flags & LLOG_F_ZAP_WHEN_EMPTY)) {
 250                 rc = llog_declare_destroy(env, loghandle, th);
 251                 if (rc < 0)
 252                         GOTO(out_trans, rc);
 253         }
 254
 255         th->th_wait_submit = 1;
 256         rc = dt_trans_start_local(env, dt, th);
 257         if (rc < 0)
 258                 GOTO(out_trans, rc);
 259
 260         down_write(&loghandle->lgh_lock);
 261         /* clear bitmap */
 262         mutex_lock(&loghandle->lgh_hdr_mutex);
 263         for (i = 0; i < num; ++i) {
 264                 if (index[i] == 0) {
 265                         CERROR("Can't cancel index 0 which is header\n");
 266                         GOTO(out_unlock, rc = -EINVAL);
 267                 }
 268                 if (!__test_and_clear_bit_le(index[i], LLOG_HDR_BITMAP(llh))) {
 269                         CDEBUG(D_RPCTRACE, "Catalog index %u already clear?\n",
 270                                index[i]);
 271                         GOTO(out_unlock, rc = -ENOENT);
 272                 }
 273         }
 274         loghandle->lgh_hdr->llh_count -= num;
 275         subtract_count = true;
 276
 277         /* Since llog_process_thread use lgi_cookie, it`s better to save them
 278          * and restore after using
 279          */
 280         tmp_lgc_index = lgi->lgi_cookie.lgc_index;
 281         /* Pass this index to llog_osd_write_rec(), which will use the index
 282          * to only update the necesary bitmap. */
 283         lgi->lgi_cookie.lgc_index = index[0];
 284         /* update header */
 285         rc = llog_write_rec(env, loghandle, &llh->llh_hdr, (num != 1 ? NULL :
 286                             &lgi->lgi_cookie), LLOG_HEADER_IDX, th);
 287         lgi->lgi_cookie.lgc_index = tmp_lgc_index;
 288
 289         if (rc != 0)
 290                 GOTO(out_unlock, rc);
 291
 292         if ((llh->llh_flags & LLOG_F_ZAP_WHEN_EMPTY) &&
 293             (llh->llh_count == 1) &&
 294             ((loghandle->lgh_last_idx == LLOG_HDR_BITMAP_SIZE(llh) - 1) ||
 295              (loghandle->u.phd.phd_cat_handle != NULL &&
 296               loghandle->u.phd.phd_cat_handle->u.chd.chd_current_log !=
 297                 loghandle))) {
 298                 /* never try to destroy it again */
 299                 llh->llh_flags &= ~LLOG_F_ZAP_WHEN_EMPTY;
 300                 rc = llog_trans_destroy(env, loghandle, th);
 301                 if (rc < 0) {
 302                         /* Sigh, can not destroy the final plain llog, but
 303                          * the bitmap has been clearly, so the record can not
 304                          * be accessed anymore, let's return 0 for now, and
 305                          * the orphan will be handled by LFSCK. */
 306                         CERROR("%s: can't destroy empty llog "DFID": rc = %d\n",
 307                                loghandle->lgh_ctxt->loc_obd->obd_name,
 308                                PFID(&loghandle->lgh_id.lgl_oi.oi_fid), rc);
 309                         GOTO(out_unlock, rc = 0);
 310                 }
 311                 rc = LLOG_DEL_PLAIN;
 312         }
 313
 314 out_unlock:
 315         mutex_unlock(&loghandle->lgh_hdr_mutex);
 316         up_write(&loghandle->lgh_lock);
 317 out_trans:
 318         rc1 = dt_trans_stop(env, dt, th);
 319         if (rc == 0)
 320                 rc = rc1;
 321         if (rc < 0) {
 322                 mutex_lock(&loghandle->lgh_hdr_mutex);
 323                 if (subtract_count)
 324                         loghandle->lgh_hdr->llh_count += num;
 325                 for (i = i - 1; i >= 0; i--)
 326                         set_bit_le(index[i], LLOG_HDR_BITMAP(llh));
 327                 mutex_unlock(&loghandle->lgh_hdr_mutex);
 328         }
 329         RETURN(rc);
 330 }
 331
 332 int llog_cancel_rec(const struct lu_env *env, struct llog_handle *loghandle,
 333                     int index)
 334 {
 335         return llog_cancel_arr_rec(env, loghandle, 1, &index);
 336 }
 337
 338 int llog_read_header(const struct lu_env *env, struct llog_handle *handle,
 339                      const struct obd_uuid *uuid)
 340 {
 341         struct llog_operations *lop;
 342         int rc;
 343         ENTRY;
 344
 345         rc = llog_handle2ops(handle, &lop);
 346         if (rc)
 347                 RETURN(rc);
 348
 349         if (lop->lop_read_header == NULL)
 350                 RETURN(-EOPNOTSUPP);
 351
 352         rc = lop->lop_read_header(env, handle);
 353         if (rc == LLOG_EEMPTY) {
 354                 struct llog_log_hdr *llh = handle->lgh_hdr;
 355
 356                 /* lrh_len should be initialized in llog_init_handle */
 357                 handle->lgh_last_idx = 0; /* header is record with index 0 */
 358                 llh->llh_count = 1;         /* for the header record */
 359                 llh->llh_hdr.lrh_type = LLOG_HDR_MAGIC;
 360                 LASSERT(handle->lgh_ctxt->loc_chunk_size >=
 361                                                 LLOG_MIN_CHUNK_SIZE);
 362                 llh->llh_hdr.lrh_len = handle->lgh_ctxt->loc_chunk_size;
 363                 llh->llh_hdr.lrh_index = 0;
 364                 llh->llh_timestamp = ktime_get_real_seconds();
 365                 if (uuid)
 366                         memcpy(&llh->llh_tgtuuid, uuid,
 367                                sizeof(llh->llh_tgtuuid));
 368                 llh->llh_bitmap_offset = offsetof(typeof(*llh), llh_bitmap);
 369                 /* Since update llog header might also call this function,
 370                  * let's reset the bitmap to 0 here */
 371                 memset(LLOG_HDR_BITMAP(llh), 0, llh->llh_hdr.lrh_len -
 372                                                 llh->llh_bitmap_offset -
 373                                                 sizeof(llh->llh_tail));
 374                 set_bit_le(0, LLOG_HDR_BITMAP(llh));
 375                 LLOG_HDR_TAIL(llh)->lrt_len = llh->llh_hdr.lrh_len;
 376                 LLOG_HDR_TAIL(llh)->lrt_index = llh->llh_hdr.lrh_index;
 377                 rc = 0;
 378         }
 379         RETURN(rc);
 380 }
 381 EXPORT_SYMBOL(llog_read_header);
 382
 383 int llog_init_handle(const struct lu_env *env, struct llog_handle *handle,
 384                      int flags, struct obd_uuid *uuid)
 385 {
 386         struct llog_log_hdr     *llh;
 387         enum llog_flag           fmt = flags & LLOG_F_EXT_MASK;
 388         int                      rc;
 389         int                     chunk_size = handle->lgh_ctxt->loc_chunk_size;
 390         ENTRY;
 391
 392         LASSERT(handle->lgh_hdr == NULL);
 393
 394         LASSERT(chunk_size >= LLOG_MIN_CHUNK_SIZE);
 395         OBD_ALLOC_LARGE(llh, chunk_size);
 396         if (llh == NULL)
 397                 RETURN(-ENOMEM);
 398
 399         handle->lgh_hdr = llh;
 400         handle->lgh_hdr_size = chunk_size;
 401         /* first assign flags to use llog_client_ops */
 402         llh->llh_flags = flags;
 403         rc = llog_read_header(env, handle, uuid);
 404         if (rc == 0) {
 405                 if (unlikely((llh->llh_flags & LLOG_F_IS_PLAIN &&
 406                               flags & LLOG_F_IS_CAT) ||
 407                              (llh->llh_flags & LLOG_F_IS_CAT &&
 408                               flags & LLOG_F_IS_PLAIN))) {
 409                         CERROR("%s: llog type is %s but initializing %s\n",
 410                                handle->lgh_ctxt->loc_obd->obd_name,
 411                                llh->llh_flags & LLOG_F_IS_CAT ?
 412                                "catalog" : "plain",
 413                                flags & LLOG_F_IS_CAT ? "catalog" : "plain");
 414                         GOTO(out, rc = -EINVAL);
 415                 } else if (llh->llh_flags &
 416                            (LLOG_F_IS_PLAIN | LLOG_F_IS_CAT)) {
 417                         /*
 418                          * it is possible to open llog without specifying llog
 419                          * type so it is taken from llh_flags
 420                          */
 421                         flags = llh->llh_flags;
 422                 } else {
 423                         /* for some reason the llh_flags has no type set */
 424                         CERROR("llog type is not specified!\n");
 425                         GOTO(out, rc = -EINVAL);
 426                 }
 427                 if (unlikely(uuid &&
 428                              !obd_uuid_equals(uuid, &llh->llh_tgtuuid))) {
 429                         CERROR("%s: llog uuid mismatch: %s/%s\n",
 430                                handle->lgh_ctxt->loc_obd->obd_name,
 431                                (char *)uuid->uuid,
 432                                (char *)llh->llh_tgtuuid.uuid);
 433                         GOTO(out, rc = -EEXIST);
 434                 }
 435         }
 436         if (flags & LLOG_F_IS_CAT) {
 437                 LASSERT(list_empty(&handle->u.chd.chd_head));
 438                 INIT_LIST_HEAD(&handle->u.chd.chd_head);
 439                 llh->llh_size = sizeof(struct llog_logid_rec);
 440                 llh->llh_flags |= LLOG_F_IS_FIXSIZE;
 441         } else if (!(flags & LLOG_F_IS_PLAIN)) {
 442                 CERROR("%s: unknown flags: %#x (expected %#x or %#x)\n",
 443                        handle->lgh_ctxt->loc_obd->obd_name,
 444                        flags, LLOG_F_IS_CAT, LLOG_F_IS_PLAIN);
 445                 rc = -EINVAL;
 446         }
 447         llh->llh_flags |= fmt;
 448 out:
 449         if (rc) {
 450                 OBD_FREE_LARGE(llh, chunk_size);
 451                 handle->lgh_hdr = NULL;
 452         }
 453         RETURN(rc);
 454 }
 455 EXPORT_SYMBOL(llog_init_handle);
 456
 457 static int llog_process_thread(void *arg)
 458 {
 459         struct llog_process_info        *lpi = arg;
 460         struct llog_handle              *loghandle = lpi->lpi_loghandle;
 461         struct llog_log_hdr             *llh = loghandle->lgh_hdr;
 462         struct llog_process_cat_data    *cd  = lpi->lpi_catdata;
 463         struct llog_thread_info         *lti;
 464         char                            *buf;
 465         size_t                           chunk_size;
 466         __u64                            cur_offset;
 467         int                              rc = 0, index = 1, last_index;
 468         int                              saved_index = 0;
 469         int                              last_called_index = 0;
 470         bool                             repeated = false;
 471
 472         ENTRY;
 473
 474         if (llh == NULL)
 475                 RETURN(-EINVAL);
 476
 477         lti = lpi->lpi_env == NULL ? NULL : llog_info(lpi->lpi_env);
 478
 479         cur_offset = chunk_size = llh->llh_hdr.lrh_len;
 480         /* expect chunk_size to be power of two */
 481         LASSERT(is_power_of_2(chunk_size));
 482
 483         OBD_ALLOC_LARGE(buf, chunk_size);
 484         if (buf == NULL) {
 485                 lpi->lpi_rc = -ENOMEM;
 486                 RETURN(0);
 487         }
 488
 489         if (cd != NULL) {
 490                 last_called_index = cd->lpcd_first_idx;
 491                 index = cd->lpcd_first_idx + 1;
 492         }
 493         if (cd != NULL && cd->lpcd_last_idx)
 494                 last_index = cd->lpcd_last_idx;
 495         else
 496                 last_index = LLOG_HDR_BITMAP_SIZE(llh) - 1;
 497
 498         while (rc == 0) {
 499                 struct llog_rec_hdr *rec;
 500                 off_t chunk_offset = 0;
 501                 unsigned int buf_offset = 0;
 502                 int     lh_last_idx;
 503                 int     synced_idx = 0;
 504
 505                 /* skip records not set in bitmap */
 506                 while (index <= last_index &&
 507                        !test_bit_le(index, LLOG_HDR_BITMAP(llh)))
 508                         ++index;
 509
 510                 /* There are no indices prior the last_index */
 511                 if (index > last_index)
 512                         break;
 513
 514                 CDEBUG(D_OTHER, "index: %d last_index %d\n", index,
 515                        last_index);
 516
 517 repeat:
 518                 /* get the buf with our target record; avoid old garbage */
 519                 memset(buf, 0, chunk_size);
 520                 /* the record index for outdated chunk data */
 521                 /* it is safe to process buffer until saved lgh_last_idx */
 522                 lh_last_idx = LLOG_HDR_TAIL(llh)->lrt_index;
 523                 rc = llog_next_block(lpi->lpi_env, loghandle, &saved_index,
 524                                      index, &cur_offset, buf, chunk_size);
 525                 if (repeated && rc)
 526                         CDEBUG(D_OTHER, "cur_offset %llu, chunk_offset %llu,"
 527                                " buf_offset %u, rc = %d\n", cur_offset,
 528                                (__u64)chunk_offset, buf_offset, rc);
 529                 /* we`ve tried to reread the chunk, but there is no
 530                  * new records */
 531                 if (rc == -EIO && repeated && (chunk_offset + buf_offset) ==
 532                     cur_offset)
 533                         GOTO(out, rc = 0);
 534                 if (rc != 0)
 535                         GOTO(out, rc);
 536
 537                 /* NB: after llog_next_block() call the cur_offset is the
 538                  * offset of the next block after read one.
 539                  * The absolute offset of the current chunk is calculated
 540                  * from cur_offset value and stored in chunk_offset variable.
 541                  */
 542                 if ((cur_offset & (chunk_size - 1)) != 0)
 543                         chunk_offset = cur_offset & ~(chunk_size - 1);
 544                 else
 545                         chunk_offset = cur_offset - chunk_size;
 546
 547                 /* NB: when rec->lrh_len is accessed it is already swabbed
 548                  * since it is used at the "end" of the loop and the rec
 549                  * swabbing is done at the beginning of the loop. */
 550                 for (rec = (struct llog_rec_hdr *)(buf + buf_offset);
 551                      (char *)rec < buf + chunk_size;
 552                      rec = llog_rec_hdr_next(rec)) {
 553
 554                         CDEBUG(D_OTHER, "processing rec 0x%p type %#x\n",
 555                                rec, rec->lrh_type);
 556
 557                         if (LLOG_REC_HDR_NEEDS_SWABBING(rec))
 558                                 lustre_swab_llog_rec(rec);
 559
 560                         CDEBUG(D_OTHER, "after swabbing, type=%#x idx=%d\n",
 561                                rec->lrh_type, rec->lrh_index);
 562
 563                         if (index == (synced_idx + 1) &&
 564                             synced_idx == LLOG_HDR_TAIL(llh)->lrt_index)
 565                                 GOTO(out, rc = 0);
 566
 567                         if (OBD_FAIL_PRECHECK(OBD_FAIL_LLOG_PROCESS_TIMEOUT) &&
 568                                 cfs_fail_val == (unsigned int)
 569                                         (loghandle->lgh_id.lgl_oi.oi.oi_id &
 570                                          0xFFFFFFFF)) {
 571                                 OBD_RACE(OBD_FAIL_LLOG_PROCESS_TIMEOUT);
 572                         }
 573
 574                         /* the bitmap could be changed during processing
 575                          * records from the chunk. For wrapped catalog
 576                          * it means we can read deleted record and try to
 577                          * process it. Check this case and reread the chunk.
 578                          * It is safe to process to lh_last_idx, including
 579                          * lh_last_idx if it was synced. We can not do <=
 580                          * comparison, cause for wrapped catalog lgh_last_idx
 581                          * could be less than index. So we detect last index
 582                          * for processing as index == lh_last_idx+1. But when
 583                          * catalog is wrapped and full lgh_last_idx=llh_cat_idx,
 584                          * the first processing index is llh_cat_idx+1.The
 585                          * exception is !(lgh_last_idx == llh_cat_idx &&
 586                          * index == llh_cat_idx + 1), and after simplification
 587                          * it turns to
 588                          * lh_last_idx != LLOG_HDR_TAIL(llh)->lrt_index
 589                          * This exception is working for catalog only.
 590                          */
 591
 592                         if ((index == lh_last_idx && synced_idx != index) ||
 593                             (index == (lh_last_idx + 1) &&
 594                              lh_last_idx != LLOG_HDR_TAIL(llh)->lrt_index) ||
 595                             (rec->lrh_index == 0 && !repeated)) {
 596
 597                                 /* save offset inside buffer for the re-read */
 598                                 buf_offset = (char *)rec - (char *)buf;
 599                                 cur_offset = chunk_offset;
 600                                 repeated = true;
 601                                 /* We need to be sure lgh_last_idx
 602                                  * record was saved to disk
 603                                  */
 604                                 down_read(&loghandle->lgh_last_sem);
 605                                 synced_idx = LLOG_HDR_TAIL(llh)->lrt_index;
 606                                 up_read(&loghandle->lgh_last_sem);
 607                                 CDEBUG(D_OTHER, "synced_idx: %d\n", synced_idx);
 608                                 goto repeat;
 609
 610                         }
 611
 612                         repeated = false;
 613
 614                         if (rec->lrh_len == 0 || rec->lrh_len > chunk_size) {
 615                                 CWARN("%s: invalid length %d in llog "DFID
 616                                       "record for index %d/%d\n",
 617                                        loghandle->lgh_ctxt->loc_obd->obd_name,
 618                                        rec->lrh_len,
 619                                        PFID(&loghandle->lgh_id.lgl_oi.oi_fid),
 620                                        rec->lrh_index, index);
 621
 622                                 GOTO(out, rc = -EINVAL);
 623                         }
 624
 625                         if (rec->lrh_index < index) {
 626                                 CDEBUG(D_OTHER, "skipping lrh_index %d\n",
 627                                        rec->lrh_index);
 628                                 continue;
 629                         }
 630
 631                         if (rec->lrh_index != index) {
 632                                 CERROR("%s: "DFID" Invalid record: index %u"
 633                                        " but expected %u\n",
 634                                        loghandle->lgh_ctxt->loc_obd->obd_name,
 635                                        PFID(&loghandle->lgh_id.lgl_oi.oi_fid),
 636                                        rec->lrh_index, index);
 637                                 GOTO(out, rc = -ERANGE);
 638                         }
 639
 640                         CDEBUG(D_OTHER,
 641                                "lrh_index: %d lrh_len: %d (%d remains)\n",
 642                                rec->lrh_index, rec->lrh_len,
 643                                (int)(buf + chunk_size - (char *)rec));
 644
 645                         /* lgh_cur_offset is used only at llog_test_3 */
 646                         loghandle->lgh_cur_offset = (char *)rec - (char *)buf +
 647                                                     chunk_offset;
 648
 649                         /* if set, process the callback on this record */
 650                         if (test_bit_le(index, LLOG_HDR_BITMAP(llh))) {
 651                                 struct llog_cookie *lgc;
 652                                 __u64   tmp_off;
 653                                 int     tmp_idx;
 654
 655                                 CDEBUG((llh->llh_flags & LLOG_F_IS_CAT ?
 656                                         D_HA : D_OTHER),
 657                                        "index: %d, lh_last_idx: %d "
 658                                        "synced_idx: %d lgh_last_idx: %d\n",
 659                                        index, lh_last_idx, synced_idx,
 660                                        loghandle->lgh_last_idx);
 661
 662                                 if (lti != NULL) {
 663                                         lgc = &lti->lgi_cookie;
 664                                         /* store lu_env for recursive calls */
 665                                         tmp_off = lgc->lgc_offset;
 666                                         tmp_idx = lgc->lgc_index;
 667
 668                                         lgc->lgc_offset = (char *)rec -
 669                                                 (char *)buf + chunk_offset;
 670                                         lgc->lgc_index = rec->lrh_index;
 671                                 }
 672                                 /* using lu_env for passing record offset to
 673                                  * llog_write through various callbacks */
 674                                 rc = lpi->lpi_cb(lpi->lpi_env, loghandle, rec,
 675                                                  lpi->lpi_cbdata);
 676                                 last_called_index = index;
 677
 678                                 if (lti != NULL) {
 679                                         lgc->lgc_offset = tmp_off;
 680                                         lgc->lgc_index = tmp_idx;
 681                                 }
 682
 683                                 if (rc == LLOG_PROC_BREAK) {
 684                                         GOTO(out, rc);
 685                                 } else if (rc == LLOG_DEL_RECORD) {
 686                                         rc = llog_cancel_rec(lpi->lpi_env,
 687                                                              loghandle,
 688                                                              rec->lrh_index);
 689                                 }
 690                                 if (rc)
 691                                         GOTO(out, rc);
 692                                 /* some stupid callbacks directly cancel records
 693                                  * and delete llog. Check it and stop
 694                                  * processing. */
 695                                 if (loghandle->lgh_hdr == NULL ||
 696                                     loghandle->lgh_hdr->llh_count == 1)
 697                                         GOTO(out, rc = 0);
 698                         }
 699                         /* exit if the last index is reached */
 700                         if (index >= last_index)
 701                                 GOTO(out, rc = 0);
 702                         ++index;
 703                 }
 704         }
 705
 706 out:
 707         CDEBUG(D_HA, "stop processing %s "DOSTID":%x index %d count %d\n",
 708                ((llh->llh_flags & LLOG_F_IS_CAT) ? "catalog" : "plain"),
 709                POSTID(&loghandle->lgh_id.lgl_oi), loghandle->lgh_id.lgl_ogen,
 710                index, llh->llh_count);
 711
 712         if (cd != NULL)
 713                 cd->lpcd_last_idx = last_called_index;
 714
 715         if (unlikely(rc == -EIO && loghandle->lgh_obj != NULL)) {
 716                 if (dt_object_remote(loghandle->lgh_obj)) {
 717                         /* If it is remote object, then -EIO might means
 718                          * disconnection or eviction, let's return -EAGAIN,
 719                          * so for update recovery log processing, it will
 720                          * retry until the umount or abort recovery, see
 721                          * lod_sub_recovery_thread() */
 722                         CERROR("%s retry remote llog process\n",
 723                                loghandle->lgh_ctxt->loc_obd->obd_name);
 724                         rc = -EAGAIN;
 725                 } else {
 726                         /* something bad happened to the processing of a local
 727                          * llog file, probably I/O error or the log got
 728                          * corrupted to be able to finally release the log we
 729                          * discard any remaining bits in the header */
 730                         CERROR("%s: Local llog found corrupted #"DOSTID":%x"
 731                                " %s index %d count %d\n",
 732                                loghandle->lgh_ctxt->loc_obd->obd_name,
 733                                POSTID(&loghandle->lgh_id.lgl_oi),
 734                                loghandle->lgh_id.lgl_ogen,
 735                                ((llh->llh_flags & LLOG_F_IS_CAT) ? "catalog" :
 736                                 "plain"), index, llh->llh_count);
 737
 738                         while (index <= last_index) {
 739                                 if (test_bit_le(index,
 740                                                   LLOG_HDR_BITMAP(llh)) != 0)
 741                                         llog_cancel_rec(lpi->lpi_env, loghandle,
 742                                                         index);
 743                                 index++;
 744                         }
 745                         rc = 0;
 746                 }
 747         }
 748
 749         OBD_FREE_LARGE(buf, chunk_size);
 750         lpi->lpi_rc = rc;
 751         return 0;
 752 }
 753
 754 static int llog_process_thread_daemonize(void *arg)
 755 {
 756         struct llog_process_info        *lpi = arg;
 757         struct lu_env                    env;
 758         int                              rc;
 759         struct nsproxy                  *new_ns, *curr_ns = current->nsproxy;
 760
 761         task_lock(lpi->lpi_reftask);
 762         new_ns = lpi->lpi_reftask->nsproxy;
 763         if (curr_ns != new_ns) {
 764                 get_nsproxy(new_ns);
 765
 766                 current->nsproxy = new_ns;
 767                 /* XXX: we should call put_nsproxy() instead of
 768                  * atomic_dec(&ns->count) directly. But put_nsproxy() cannot be
 769                  * used outside of the kernel itself, because it calls
 770                  * free_nsproxy() which is not exported by the kernel
 771                  * (defined in kernel/nsproxy.c) */
 772                 if (curr_ns)
 773                         atomic_dec(&curr_ns->count);
 774         }
 775         task_unlock(lpi->lpi_reftask);
 776
 777         unshare_fs_struct();
 778
 779         /* client env has no keys, tags is just 0 */
 780         rc = lu_env_init(&env, LCT_LOCAL | LCT_MG_THREAD);
 781         if (rc)
 782                 goto out;
 783         lpi->lpi_env = &env;
 784
 785         rc = llog_process_thread(arg);
 786
 787         lu_env_fini(&env);
 788 out:
 789         complete(&lpi->lpi_completion);
 790         return rc;
 791 }
 792
 793 int llog_process_or_fork(const struct lu_env *env,
 794                          struct llog_handle *loghandle,
 795                          llog_cb_t cb, void *data, void *catdata, bool fork)
 796 {
 797         struct llog_process_info *lpi;
 798         struct llog_process_data *d = data;
 799         struct llog_process_cat_data *cd = catdata;
 800         __u32 flags = loghandle->lgh_hdr->llh_flags;
 801         int rc;
 802
 803         ENTRY;
 804
 805         OBD_ALLOC_PTR(lpi);
 806         if (lpi == NULL) {
 807                 CERROR("cannot alloc pointer\n");
 808                 RETURN(-ENOMEM);
 809         }
 810         lpi->lpi_loghandle = loghandle;
 811         lpi->lpi_cb        = cb;
 812         lpi->lpi_cbdata    = data;
 813         lpi->lpi_catdata   = catdata;
 814
 815         CDEBUG(D_OTHER, "Processing "DFID" flags 0x%03x startcat %d startidx %d first_idx %d last_idx %d\n",
 816                PFID(&loghandle->lgh_id.lgl_oi.oi_fid), flags,
 817                (flags & LLOG_F_IS_CAT) && d ? d->lpd_startcat : -1,
 818                (flags & LLOG_F_IS_CAT) && d ? d->lpd_startidx : -1,
 819                cd ? cd->lpcd_first_idx : -1, cd ? cd->lpcd_last_idx : -1);
 820         if (fork) {
 821                 struct task_struct *task;
 822
 823                 /* The new thread can't use parent env,
 824                  * init the new one in llog_process_thread_daemonize. */
 825                 lpi->lpi_env = NULL;
 826                 init_completion(&lpi->lpi_completion);
 827                 /* take reference to current, so that
 828                  * llog_process_thread_daemonize() can use it to switch to
 829                  * namespace associated with current  */
 830                 lpi->lpi_reftask = current;
 831                 task = kthread_run(llog_process_thread_daemonize, lpi,
 832                                    "llog_process_thread");
 833                 if (IS_ERR(task)) {
 834                         rc = PTR_ERR(task);
 835                         CERROR("%s: cannot start thread: rc = %d\n",
 836                                loghandle->lgh_ctxt->loc_obd->obd_name, rc);
 837                         GOTO(out_lpi, rc);
 838                 }
 839                 wait_for_completion(&lpi->lpi_completion);
 840         } else {
 841                 lpi->lpi_env = env;
 842                 llog_process_thread(lpi);
 843         }
 844         rc = lpi->lpi_rc;
 845
 846 out_lpi:
 847         OBD_FREE_PTR(lpi);
 848         RETURN(rc);
 849 }
 850 EXPORT_SYMBOL(llog_process_or_fork);
 851
 852 int llog_process(const struct lu_env *env, struct llog_handle *loghandle,
 853                  llog_cb_t cb, void *data, void *catdata)
 854 {
 855         int rc;
 856         rc = llog_process_or_fork(env, loghandle, cb, data, catdata, true);
 857         return rc == LLOG_DEL_PLAIN ? 0 : rc;
 858 }
 859 EXPORT_SYMBOL(llog_process);
 860
 861 static inline const struct cred *llog_raise_resource(void)
 862 {
 863         struct cred *cred = NULL;
 864
 865         if (cap_raised(current_cap(), CAP_SYS_RESOURCE))
 866                 return cred;
 867
 868         cred = prepare_creds();
 869         if (!cred)
 870                 return cred;
 871
 872         cap_raise(cred->cap_effective, CAP_SYS_RESOURCE);
 873         return override_creds(cred);
 874 }
 875
 876 static inline void llog_restore_resource(const struct cred *old_cred)
 877 {
 878         if (old_cred)
 879                 revert_creds(old_cred);
 880 }
 881
 882 int llog_reverse_process(const struct lu_env *env,
 883                          struct llog_handle *loghandle, llog_cb_t cb,
 884                          void *data, void *catdata)
 885 {
 886         struct llog_log_hdr *llh = loghandle->lgh_hdr;
 887         struct llog_process_cat_data *cd = catdata;
 888         void *buf;
 889         int rc = 0, first_index = 1, index, idx;
 890         __u32   chunk_size = llh->llh_hdr.lrh_len;
 891         ENTRY;
 892
 893         OBD_ALLOC_LARGE(buf, chunk_size);
 894         if (buf == NULL)
 895                 RETURN(-ENOMEM);
 896
 897         if (cd != NULL)
 898                 first_index = cd->lpcd_first_idx + 1;
 899         if (cd != NULL && cd->lpcd_last_idx)
 900                 index = cd->lpcd_last_idx;
 901         else
 902                 index = LLOG_HDR_BITMAP_SIZE(llh) - 1;
 903
 904         while (rc == 0) {
 905                 struct llog_rec_hdr *rec;
 906                 struct llog_rec_tail *tail;
 907
 908                 /* skip records not set in bitmap */
 909                 while (index >= first_index &&
 910                        !test_bit_le(index, LLOG_HDR_BITMAP(llh)))
 911                         --index;
 912
 913                 LASSERT(index >= first_index - 1);
 914                 if (index == first_index - 1)
 915                         break;
 916
 917                 /* get the buf with our target record; avoid old garbage */
 918                 memset(buf, 0, chunk_size);
 919                 rc = llog_prev_block(env, loghandle, index, buf, chunk_size);
 920                 if (rc)
 921                         GOTO(out, rc);
 922
 923                 rec = buf;
 924                 idx = rec->lrh_index;
 925                 CDEBUG(D_RPCTRACE, "index %u : idx %u\n", index, idx);
 926                 while (idx < index) {
 927                         rec = (void *)rec + rec->lrh_len;
 928                         if (LLOG_REC_HDR_NEEDS_SWABBING(rec))
 929                                 lustre_swab_llog_rec(rec);
 930                         idx ++;
 931                 }
 932                 LASSERT(idx == index);
 933                 tail = (void *)rec + rec->lrh_len - sizeof(*tail);
 934
 935                 /* process records in buffer, starting where we found one */
 936                 while ((void *)tail > buf) {
 937                         if (tail->lrt_index == 0)
 938                                 GOTO(out, rc = 0); /* no more records */
 939
 940                         /* if set, process the callback on this record */
 941                         if (test_bit_le(index, LLOG_HDR_BITMAP(llh))) {
 942                                 rec = (void *)tail - tail->lrt_len +
 943                                       sizeof(*tail);
 944
 945                                 rc = cb(env, loghandle, rec, data);
 946                                 if (rc == LLOG_PROC_BREAK) {
 947                                         GOTO(out, rc);
 948                                 } else if (rc == LLOG_DEL_RECORD) {
 949                                         rc = llog_cancel_rec(env, loghandle,
 950                                                              tail->lrt_index);
 951                                 }
 952                                 if (rc)
 953                                         GOTO(out, rc);
 954                         }
 955
 956                         /* previous record, still in buffer? */
 957                         --index;
 958                         if (index < first_index)
 959                                 GOTO(out, rc = 0);
 960                         tail = (void *)tail - tail->lrt_len;
 961                 }
 962         }
 963
 964 out:
 965         if (buf != NULL)
 966                 OBD_FREE_LARGE(buf, chunk_size);
 967         RETURN(rc);
 968 }
 969 EXPORT_SYMBOL(llog_reverse_process);
 970
 971 /**
 972  * new llog API
 973  *
 974  * API functions:
 975  *      llog_open - open llog, may not exist
 976  *      llog_exist - check if llog exists
 977  *      llog_close - close opened llog, pair for open, frees llog_handle
 978  *      llog_declare_create - declare llog creation
 979  *      llog_create - create new llog on disk, need transaction handle
 980  *      llog_declare_write_rec - declaration of llog write
 981  *      llog_write_rec - write llog record on disk, need transaction handle
 982  *      llog_declare_add - declare llog catalog record addition
 983  *      llog_add - add llog record in catalog, need transaction handle
 984  */
 985 int llog_exist(struct llog_handle *loghandle)
 986 {
 987         struct llog_operations  *lop;
 988         int                      rc;
 989
 990         ENTRY;
 991
 992         rc = llog_handle2ops(loghandle, &lop);
 993         if (rc)
 994                 RETURN(rc);
 995         if (lop->lop_exist == NULL)
 996                 RETURN(-EOPNOTSUPP);
 997
 998         rc = lop->lop_exist(loghandle);
 999         RETURN(rc);
1000 }
1001 EXPORT_SYMBOL(llog_exist);
1002
1003 int llog_declare_create(const struct lu_env *env,
1004                         struct llog_handle *loghandle, struct thandle *th)
1005 {
1006         const struct cred *old_cred;
1007         struct llog_operations  *lop;
1008         int rc;
1009
1010         ENTRY;
1011
1012         rc = llog_handle2ops(loghandle, &lop);
1013         if (rc)
1014                 RETURN(rc);
1015         if (lop->lop_declare_create == NULL)
1016                 RETURN(-EOPNOTSUPP);
1017
1018         old_cred = llog_raise_resource();
1019         rc = lop->lop_declare_create(env, loghandle, th);
1020         llog_restore_resource(old_cred);
1021         RETURN(rc);
1022 }
1023
1024 int llog_create(const struct lu_env *env, struct llog_handle *handle,
1025                 struct thandle *th)
1026 {
1027         const struct cred *old_cred;
1028         struct llog_operations  *lop;
1029         int rc;
1030
1031         ENTRY;
1032
1033         rc = llog_handle2ops(handle, &lop);
1034         if (rc)
1035                 RETURN(rc);
1036         if (lop->lop_create == NULL)
1037                 RETURN(-EOPNOTSUPP);
1038
1039         old_cred = llog_raise_resource();
1040         rc = lop->lop_create(env, handle, th);
1041         llog_restore_resource(old_cred);
1042         RETURN(rc);
1043 }
1044
1045 int llog_declare_write_rec(const struct lu_env *env,
1046                            struct llog_handle *handle,
1047                            struct llog_rec_hdr *rec, int idx,
1048                            struct thandle *th)
1049 {
1050         const struct cred *old_cred;
1051         struct llog_operations  *lop;
1052         int rc;
1053
1054         ENTRY;
1055
1056         rc = llog_handle2ops(handle, &lop);
1057         if (rc)
1058                 RETURN(rc);
1059         LASSERT(lop);
1060         if (lop->lop_declare_write_rec == NULL)
1061                 RETURN(-EOPNOTSUPP);
1062
1063         old_cred = llog_raise_resource();
1064         rc = lop->lop_declare_write_rec(env, handle, rec, idx, th);
1065         llog_restore_resource(old_cred);
1066         RETURN(rc);
1067 }
1068
1069 int llog_write_rec(const struct lu_env *env, struct llog_handle *handle,
1070                    struct llog_rec_hdr *rec, struct llog_cookie *logcookies,
1071                    int idx, struct thandle *th)
1072 {
1073         const struct cred *old_cred;
1074         struct llog_operations  *lop;
1075         int rc, buflen;
1076
1077         ENTRY;
1078
1079         /* API sanity checks */
1080         if (handle == NULL) {
1081                 CERROR("loghandle is missed\n");
1082                 RETURN(-EPROTO);
1083         } else if (handle->lgh_obj == NULL) {
1084                 CERROR("loghandle %p with NULL object\n",
1085                         handle);
1086                 RETURN(-EPROTO);
1087         } else if (th == NULL) {
1088                 CERROR("%s: missed transaction handle\n",
1089                         handle->lgh_obj->do_lu.lo_dev->ld_obd->obd_name);
1090                 RETURN(-EPROTO);
1091         } else if (handle->lgh_hdr == NULL) {
1092                 CERROR("%s: loghandle %p with no header\n",
1093                         handle->lgh_obj->do_lu.lo_dev->ld_obd->obd_name,
1094                         handle);
1095                 RETURN(-EPROTO);
1096         }
1097
1098         rc = llog_handle2ops(handle, &lop);
1099         if (rc)
1100                 RETURN(rc);
1101
1102         if (lop->lop_write_rec == NULL)
1103                 RETURN(-EOPNOTSUPP);
1104
1105         buflen = rec->lrh_len;
1106         LASSERT(cfs_size_round(buflen) == buflen);
1107
1108         old_cred = llog_raise_resource();
1109         rc = lop->lop_write_rec(env, handle, rec, logcookies, idx, th);
1110         llog_restore_resource(old_cred);
1111         RETURN(rc);
1112 }
1113
1114 int llog_add(const struct lu_env *env, struct llog_handle *lgh,
1115              struct llog_rec_hdr *rec, struct llog_cookie *logcookies,
1116              struct thandle *th)
1117 {
1118         const struct cred *old_cred;
1119         int rc;
1120
1121         ENTRY;
1122
1123         if (lgh->lgh_logops->lop_add == NULL)
1124                 RETURN(-EOPNOTSUPP);
1125
1126         old_cred = llog_raise_resource();
1127         rc = lgh->lgh_logops->lop_add(env, lgh, rec, logcookies, th);
1128         llog_restore_resource(old_cred);
1129         RETURN(rc);
1130 }
1131 EXPORT_SYMBOL(llog_add);
1132
1133 int llog_declare_add(const struct lu_env *env, struct llog_handle *lgh,
1134                      struct llog_rec_hdr *rec, struct thandle *th)
1135 {
1136         const struct cred *old_cred;
1137         int rc;
1138
1139         ENTRY;
1140
1141         if (lgh->lgh_logops->lop_declare_add == NULL)
1142                 RETURN(-EOPNOTSUPP);
1143
1144         old_cred = llog_raise_resource();
1145         rc = lgh->lgh_logops->lop_declare_add(env, lgh, rec, th);
1146         llog_restore_resource(old_cred);
1147         RETURN(rc);
1148 }
1149 EXPORT_SYMBOL(llog_declare_add);
1150
1151 /**
1152  * Helper function to open llog or create it if doesn't exist.
1153  * It hides all transaction handling from caller.
1154  */
1155 int llog_open_create(const struct lu_env *env, struct llog_ctxt *ctxt,
1156                      struct llog_handle **res, struct llog_logid *logid,
1157                      char *name)
1158 {
1159         struct dt_device        *d;
1160         struct thandle          *th;
1161         int                      rc;
1162
1163         ENTRY;
1164
1165         rc = llog_open(env, ctxt, res, logid, name, LLOG_OPEN_NEW);
1166         if (rc)
1167                 RETURN(rc);
1168
1169         if (llog_exist(*res))
1170                 RETURN(0);
1171
1172         LASSERT((*res)->lgh_obj != NULL);
1173
1174         d = lu2dt_dev((*res)->lgh_obj->do_lu.lo_dev);
1175
1176         if (unlikely(unlikely(d->dd_rdonly)))
1177                 RETURN(-EROFS);
1178
1179         th = dt_trans_create(env, d);
1180         if (IS_ERR(th))
1181                 GOTO(out, rc = PTR_ERR(th));
1182
1183         /* Create update llog object synchronously, which
1184          * happens during inialization process see
1185          * lod_sub_prep_llog(), to make sure the update
1186          * llog object is created before corss-MDT writing
1187          * updates into the llog object */
1188         if (ctxt->loc_flags & LLOG_CTXT_FLAG_NORMAL_FID)
1189                 th->th_sync = 1;
1190
1191         th->th_wait_submit = 1;
1192         rc = llog_declare_create(env, *res, th);
1193         if (rc == 0) {
1194                 rc = dt_trans_start_local(env, d, th);
1195                 if (rc == 0)
1196                         rc = llog_create(env, *res, th);
1197         }
1198         dt_trans_stop(env, d, th);
1199 out:
1200         if (rc)
1201                 llog_close(env, *res);
1202         RETURN(rc);
1203 }
1204 EXPORT_SYMBOL(llog_open_create);
1205
1206 /**
1207  * Helper function to delete existent llog.
1208  */
1209 int llog_erase(const struct lu_env *env, struct llog_ctxt *ctxt,
1210                struct llog_logid *logid, char *name)
1211 {
1212         struct llog_handle      *handle;
1213         int                      rc = 0, rc2;
1214
1215         ENTRY;
1216
1217         /* nothing to erase */
1218         if (name == NULL && logid == NULL)
1219                 RETURN(0);
1220
1221         rc = llog_open(env, ctxt, &handle, logid, name, LLOG_OPEN_EXISTS);
1222         if (rc < 0)
1223                 RETURN(rc);
1224
1225         rc = llog_init_handle(env, handle, LLOG_F_IS_PLAIN, NULL);
1226         if (rc == 0)
1227                 rc = llog_destroy(env, handle);
1228
1229         rc2 = llog_close(env, handle);
1230         if (rc == 0)
1231                 rc = rc2;
1232         RETURN(rc);
1233 }
1234 EXPORT_SYMBOL(llog_erase);
1235
1236 /*
1237  * Helper function for write record in llog.
1238  * It hides all transaction handling from caller.
1239  * Valid only with local llog.
1240  */
1241 int llog_write(const struct lu_env *env, struct llog_handle *loghandle,
1242                struct llog_rec_hdr *rec, int idx)
1243 {
1244         struct dt_device        *dt;
1245         struct thandle          *th;
1246         bool                    need_cookie;
1247         int                     rc;
1248
1249         ENTRY;
1250
1251         LASSERT(loghandle);
1252         LASSERT(loghandle->lgh_ctxt);
1253         LASSERT(loghandle->lgh_obj != NULL);
1254
1255         dt = lu2dt_dev(loghandle->lgh_obj->do_lu.lo_dev);
1256
1257         if (unlikely(unlikely(dt->dd_rdonly)))
1258                 RETURN(-EROFS);
1259
1260         th = dt_trans_create(env, dt);
1261         if (IS_ERR(th))
1262                 RETURN(PTR_ERR(th));
1263
1264         rc = llog_declare_write_rec(env, loghandle, rec, idx, th);
1265         if (rc)
1266                 GOTO(out_trans, rc);
1267
1268         th->th_wait_submit = 1;
1269         rc = dt_trans_start_local(env, dt, th);
1270         if (rc)
1271                 GOTO(out_trans, rc);
1272
1273         need_cookie = !(idx == LLOG_HEADER_IDX || idx == LLOG_NEXT_IDX);
1274
1275         down_write(&loghandle->lgh_lock);
1276         if (need_cookie) {
1277                 struct llog_thread_info *lti = llog_info(env);
1278
1279                 /* cookie comes from llog_process_thread */
1280                 rc = llog_write_rec(env, loghandle, rec, &lti->lgi_cookie,
1281                                     rec->lrh_index, th);
1282                 /* upper layer didn`t pass cookie so change rc */
1283                 rc = (rc == 1 ? 0 : rc);
1284         } else {
1285                 rc = llog_write_rec(env, loghandle, rec, NULL, idx, th);
1286         }
1287
1288         up_write(&loghandle->lgh_lock);
1289 out_trans:
1290         dt_trans_stop(env, dt, th);
1291         RETURN(rc);
1292 }
1293 EXPORT_SYMBOL(llog_write);
1294
1295 int llog_open(const struct lu_env *env, struct llog_ctxt *ctxt,
1296               struct llog_handle **lgh, struct llog_logid *logid,
1297               char *name, enum llog_open_param open_param)
1298 {
1299         const struct cred *old_cred;
1300         int      rc;
1301
1302         ENTRY;
1303
1304         LASSERT(ctxt);
1305         LASSERT(ctxt->loc_logops);
1306
1307         if (ctxt->loc_logops->lop_open == NULL) {
1308                 *lgh = NULL;
1309                 RETURN(-EOPNOTSUPP);
1310         }
1311
1312         *lgh = llog_alloc_handle();
1313         if (*lgh == NULL)
1314                 RETURN(-ENOMEM);
1315         (*lgh)->lgh_ctxt = ctxt;
1316         (*lgh)->lgh_logops = ctxt->loc_logops;
1317
1318         old_cred = llog_raise_resource();
1319         rc = ctxt->loc_logops->lop_open(env, *lgh, logid, name, open_param);
1320         llog_restore_resource(old_cred);
1321         if (rc) {
1322                 llog_free_handle(*lgh);
1323                 *lgh = NULL;
1324         }
1325         RETURN(rc);
1326 }
1327 EXPORT_SYMBOL(llog_open);
1328
1329 int llog_close(const struct lu_env *env, struct llog_handle *loghandle)
1330 {
1331         return llog_handle_put(env, loghandle);
1332 }
1333 EXPORT_SYMBOL(llog_close);
1334
1335 /**
1336  * Helper function to get the llog size in records. It is used by MGS
1337  * mostly to check that config llog exists and contains data.
1338  *
1339  * \param[in] env       execution environment
1340  * \param[in] ctxt      llog context
1341  * \param[in] name      llog name
1342  *
1343  * \retval              true if there are records in llog besides a header
1344  * \retval              false on error or llog without records
1345  */
1346 int llog_is_empty(const struct lu_env *env, struct llog_ctxt *ctxt,
1347                   char *name)
1348 {
1349         struct llog_handle      *llh;
1350         int                      rc = 0;
1351
1352         rc = llog_open(env, ctxt, &llh, NULL, name, LLOG_OPEN_EXISTS);
1353         if (rc < 0) {
1354                 if (likely(rc == -ENOENT))
1355                         rc = 0;
1356                 GOTO(out, rc);
1357         }
1358
1359         rc = llog_init_handle(env, llh, LLOG_F_IS_PLAIN, NULL);
1360         if (rc)
1361                 GOTO(out_close, rc);
1362         rc = llog_get_size(llh);
1363
1364 out_close:
1365         llog_close(env, llh);
1366 out:
1367         /* The header is record 1, the llog is still considered as empty
1368          * if there is only header */
1369         return (rc <= 1);
1370 }
1371 EXPORT_SYMBOL(llog_is_empty);
1372
1373 int llog_copy_handler(const struct lu_env *env, struct llog_handle *llh,
1374                       struct llog_rec_hdr *rec, void *data)
1375 {
1376         struct llog_handle      *copy_llh = data;
1377
1378         /* Append all records */
1379         return llog_write(env, copy_llh, rec, LLOG_NEXT_IDX);
1380 }
1381
1382 /* backup plain llog */
1383 int llog_backup(const struct lu_env *env, struct obd_device *obd,
1384                 struct llog_ctxt *ctxt, struct llog_ctxt *bctxt,
1385                 char *name, char *backup)
1386 {
1387         struct llog_handle      *llh, *bllh;
1388         int                      rc;
1389
1390         ENTRY;
1391
1392         /* open original log */
1393         rc = llog_open(env, ctxt, &llh, NULL, name, LLOG_OPEN_EXISTS);
1394         if (rc < 0) {
1395                 /* the -ENOENT case is also reported to the caller
1396                  * but silently so it should handle that if needed.
1397                  */
1398                 if (rc != -ENOENT)
1399                         CERROR("%s: failed to open log %s: rc = %d\n",
1400                                obd->obd_name, name, rc);
1401                 RETURN(rc);
1402         }
1403
1404         rc = llog_init_handle(env, llh, LLOG_F_IS_PLAIN, NULL);
1405         if (rc)
1406                 GOTO(out_close, rc);
1407
1408         /* Make sure there's no old backup log */
1409         rc = llog_erase(env, bctxt, NULL, backup);
1410         if (rc < 0 && rc != -ENOENT)
1411                 GOTO(out_close, rc);
1412
1413         /* open backup log */
1414         rc = llog_open_create(env, bctxt, &bllh, NULL, backup);
1415         if (rc) {
1416                 CERROR("%s: failed to open backup logfile %s: rc = %d\n",
1417                        obd->obd_name, backup, rc);
1418                 GOTO(out_close, rc);
1419         }
1420
1421         /* check that backup llog is not the same object as original one */
1422         if (llh->lgh_obj == bllh->lgh_obj) {
1423                 CERROR("%s: backup llog %s to itself (%s), objects %p/%p\n",
1424                        obd->obd_name, name, backup, llh->lgh_obj,
1425                        bllh->lgh_obj);
1426                 GOTO(out_backup, rc = -EEXIST);
1427         }
1428
1429         rc = llog_init_handle(env, bllh, LLOG_F_IS_PLAIN, NULL);
1430         if (rc)
1431                 GOTO(out_backup, rc);
1432
1433         /* Copy log record by record */
1434         rc = llog_process_or_fork(env, llh, llog_copy_handler, (void *)bllh,
1435                                   NULL, false);
1436         if (rc)
1437                 CERROR("%s: failed to backup log %s: rc = %d\n",
1438                        obd->obd_name, name, rc);
1439 out_backup:
1440         llog_close(env, bllh);
1441 out_close:
1442         llog_close(env, llh);
1443         RETURN(rc);
1444 }
1445 EXPORT_SYMBOL(llog_backup);
1446
1447 /* Get size of llog */
1448 __u64 llog_size(const struct lu_env *env, struct llog_handle *llh)
1449 {
1450         int rc;
1451         struct lu_attr la;
1452
1453         rc = llh->lgh_obj->do_ops->do_attr_get(env, llh->lgh_obj, &la);
1454         if (rc) {
1455                 CERROR("%s: attr_get failed for "DFID": rc = %d\n",
1456                        llh->lgh_ctxt->loc_obd->obd_name,
1457                        PFID(&llh->lgh_id.lgl_oi.oi_fid), rc);
1458                 return 0;
1459         }
1460
1461         return la.la_size;
1462 }
1463 EXPORT_SYMBOL(llog_size);
1464