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  *
  31  * lustre/obdclass/llog.c
  32  *
  33  * OST<->MDS recovery logging infrastructure.
  34  * Invariants in implementation:
  35  * - we do not share logs among different OST<->MDS connections, so that
  36  *   if an OST or MDS fails it need only look at log(s) relevant to itself
  37  *
  38  * Author: Andreas Dilger <adilger@clusterfs.com>
  39  * Author: Alex Zhuravlev <bzzz@whamcloud.com>
  40  * Author: Mikhail Pershin <tappro@whamcloud.com>
  41  */
  42
  43 #define DEBUG_SUBSYSTEM S_LOG
  44
  45 #include <linux/fs_struct.h>
  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 /*
  55  * Allocate a new log or catalog handle
  56  * Used inside llog_open().
  57  */
  58 static struct llog_handle *llog_alloc_handle(void)
  59 {
  60         struct llog_handle *loghandle;
  61
  62         OBD_ALLOC_PTR(loghandle);
  63         if (loghandle == NULL)
  64                 return NULL;
  65
  66         init_rwsem(&loghandle->lgh_lock);
  67         mutex_init(&loghandle->lgh_hdr_mutex);
  68         init_rwsem(&loghandle->lgh_last_sem);
  69         INIT_LIST_HEAD(&loghandle->u.phd.phd_entry);
  70         refcount_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 == NULL)
  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         OBD_FREE_LARGE(loghandle->lgh_hdr, loghandle->lgh_hdr_size);
  91 out:
  92         OBD_FREE_PTR(loghandle);
  93 }
  94
  95 struct llog_handle *llog_handle_get(struct llog_handle *loghandle)
  96 {
  97         if (refcount_inc_not_zero(&loghandle->lgh_refcount))
  98                 return loghandle;
  99         return NULL;
 100 }
 101
 102 int llog_handle_put(const struct lu_env *env, struct llog_handle *loghandle)
 103 {
 104         int rc = 0;
 105
 106         if (refcount_dec_and_test(&loghandle->lgh_refcount)) {
 107                 const struct llog_operations *lop;
 108
 109                 rc = llog_handle2ops(loghandle, &lop);
 110                 if (!rc) {
 111                         if (lop->lop_close)
 112                                 rc = lop->lop_close(env, loghandle);
 113                         else
 114                                 rc = -EOPNOTSUPP;
 115                 }
 116                 llog_free_handle(loghandle);
 117         }
 118         return rc;
 119 }
 120
 121 static int llog_declare_destroy(const struct lu_env *env,
 122                                 struct llog_handle *handle,
 123                                 struct thandle *th)
 124 {
 125         const struct llog_operations *lop;
 126         int rc;
 127
 128         ENTRY;
 129
 130         rc = llog_handle2ops(handle, &lop);
 131         if (rc)
 132                 RETURN(rc);
 133         if (lop->lop_declare_destroy == NULL)
 134                 RETURN(-EOPNOTSUPP);
 135
 136         rc = lop->lop_declare_destroy(env, handle, th);
 137
 138         RETURN(rc);
 139 }
 140
 141 int llog_trans_destroy(const struct lu_env *env, struct llog_handle *handle,
 142                        struct thandle *th)
 143 {
 144         const struct llog_operations *lop;
 145         int rc;
 146         ENTRY;
 147
 148         rc = llog_handle2ops(handle, &lop);
 149         if (rc < 0)
 150                 RETURN(rc);
 151         if (lop->lop_destroy == NULL)
 152                 RETURN(-EOPNOTSUPP);
 153
 154         LASSERT(handle->lgh_obj != NULL);
 155         if (!llog_exist(handle))
 156                 RETURN(0);
 157
 158         rc = lop->lop_destroy(env, handle, th);
 159
 160         RETURN(rc);
 161 }
 162
 163 int llog_destroy(const struct lu_env *env, struct llog_handle *handle)
 164 {
 165         const struct llog_operations *lop;
 166         struct dt_device *dt;
 167         struct thandle *th;
 168         int rc;
 169
 170         ENTRY;
 171
 172         rc = llog_handle2ops(handle, &lop);
 173         if (rc < 0)
 174                 RETURN(rc);
 175         if (lop->lop_destroy == NULL)
 176                 RETURN(-EOPNOTSUPP);
 177
 178         if (handle->lgh_obj == NULL) {
 179                 /* if lgh_obj == NULL, then it is from client side destroy */
 180                 rc = lop->lop_destroy(env, handle, NULL);
 181                 RETURN(rc);
 182         }
 183
 184         if (!llog_exist(handle))
 185                 RETURN(0);
 186
 187         dt = lu2dt_dev(handle->lgh_obj->do_lu.lo_dev);
 188
 189         if (unlikely(unlikely(dt->dd_rdonly)))
 190                 RETURN(-EROFS);
 191
 192         th = dt_trans_create(env, dt);
 193         if (IS_ERR(th))
 194                 RETURN(PTR_ERR(th));
 195
 196         rc = llog_declare_destroy(env, handle, th);
 197         if (rc != 0)
 198                 GOTO(out_trans, rc);
 199
 200         rc = dt_trans_start_local(env, dt, th);
 201         if (rc < 0)
 202                 GOTO(out_trans, rc);
 203
 204         rc = lop->lop_destroy(env, handle, th);
 205
 206 out_trans:
 207         dt_trans_stop(env, dt, th);
 208
 209         RETURN(rc);
 210 }
 211 EXPORT_SYMBOL(llog_destroy);
 212
 213 /* returns negative on error; 0 if success; 1 if success & log destroyed */
 214 int llog_cancel_arr_rec(const struct lu_env *env, struct llog_handle *loghandle,
 215                         int num, int *index)
 216 {
 217         struct llog_thread_info *lgi = llog_info(env);
 218         struct dt_device        *dt;
 219         struct llog_log_hdr     *llh;
 220         struct thandle          *th;
 221         __u32                    tmp_lgc_index;
 222         int                      rc, i = 0;
 223         int rc1;
 224         bool subtract_count = false;
 225
 226         ENTRY;
 227
 228         LASSERT(loghandle != NULL);
 229         LASSERT(loghandle->lgh_ctxt != NULL);
 230         LASSERT(loghandle->lgh_obj != NULL);
 231
 232         llh = loghandle->lgh_hdr;
 233
 234         CDEBUG(D_RPCTRACE, "Canceling %d records, first %d in log "DFID"\n",
 235                num, index[0], PFID(&loghandle->lgh_id.lgl_oi.oi_fid));
 236
 237         dt = lu2dt_dev(loghandle->lgh_obj->do_lu.lo_dev);
 238
 239         if (unlikely(unlikely(dt->dd_rdonly)))
 240                 RETURN(0);
 241
 242         th = dt_trans_create(env, dt);
 243         if (IS_ERR(th))
 244                 RETURN(PTR_ERR(th));
 245
 246         rc = llog_declare_write_rec(env, loghandle, &llh->llh_hdr, 0, th);
 247         if (rc < 0)
 248                 GOTO(out_trans, rc);
 249
 250         if ((llh->llh_flags & LLOG_F_ZAP_WHEN_EMPTY)) {
 251                 rc = llog_declare_destroy(env, loghandle, th);
 252                 if (rc < 0)
 253                         GOTO(out_trans, rc);
 254         }
 255
 256         th->th_wait_submit = 1;
 257         rc = dt_trans_start_local(env, dt, th);
 258         if (rc < 0)
 259                 GOTO(out_trans, rc);
 260
 261         down_write(&loghandle->lgh_lock);
 262         /* clear bitmap */
 263         mutex_lock(&loghandle->lgh_hdr_mutex);
 264         for (i = 0; i < num; ++i) {
 265                 if (index[i] == 0) {
 266                         CERROR("Can't cancel index 0 which is header\n");
 267                         GOTO(out_unlock, rc = -EINVAL);
 268                 }
 269                 if (!__test_and_clear_bit_le(index[i], LLOG_HDR_BITMAP(llh))) {
 270                         CDEBUG(D_RPCTRACE, "Catalog index %u already clear?\n",
 271                                index[i]);
 272                         GOTO(out_unlock, rc = -ENOENT);
 273                 }
 274         }
 275         loghandle->lgh_hdr->llh_count -= num;
 276         subtract_count = true;
 277
 278         /* Since llog_process_thread use lgi_cookie, it`s better to save them
 279          * and restore after using
 280          */
 281         tmp_lgc_index = lgi->lgi_cookie.lgc_index;
 282         /* Pass this index to llog_osd_write_rec(), which will use the index
 283          * to only update the necesary bitmap. */
 284         lgi->lgi_cookie.lgc_index = index[0];
 285         /* update header */
 286         rc = llog_write_rec(env, loghandle, &llh->llh_hdr, (num != 1 ? NULL :
 287                             &lgi->lgi_cookie), LLOG_HEADER_IDX, th);
 288         lgi->lgi_cookie.lgc_index = tmp_lgc_index;
 289
 290         if (rc != 0)
 291                 GOTO(out_unlock, rc);
 292
 293         if ((llh->llh_flags & LLOG_F_ZAP_WHEN_EMPTY) &&
 294             (llh->llh_count == 1) &&
 295             ((loghandle->lgh_last_idx == LLOG_HDR_BITMAP_SIZE(llh) - 1) ||
 296              (loghandle->u.phd.phd_cat_handle != NULL &&
 297               loghandle->u.phd.phd_cat_handle->u.chd.chd_current_log !=
 298                 loghandle))) {
 299                 /* never try to destroy it again */
 300                 llh->llh_flags &= ~LLOG_F_ZAP_WHEN_EMPTY;
 301                 rc = llog_trans_destroy(env, loghandle, th);
 302                 if (rc < 0) {
 303                         /* Sigh, can not destroy the final plain llog, but
 304                          * the bitmap has been clearly, so the record can not
 305                          * be accessed anymore, let's return 0 for now, and
 306                          * the orphan will be handled by LFSCK. */
 307                         CERROR("%s: can't destroy empty llog "DFID": rc = %d\n",
 308                                loghandle2name(loghandle),
 309                                PFID(&loghandle->lgh_id.lgl_oi.oi_fid), rc);
 310                         GOTO(out_unlock, rc = 0);
 311                 }
 312                 rc = LLOG_DEL_PLAIN;
 313         }
 314
 315 out_unlock:
 316         if (rc < 0) {
 317                 /* restore bitmap while holding a mutex */
 318                 if (subtract_count) {
 319                         loghandle->lgh_hdr->llh_count += num;
 320                         subtract_count = false;
 321                 }
 322                 for (i = i - 1; i >= 0; i--)
 323                         set_bit_le(index[i], LLOG_HDR_BITMAP(llh));
 324         }
 325         mutex_unlock(&loghandle->lgh_hdr_mutex);
 326         up_write(&loghandle->lgh_lock);
 327 out_trans:
 328         rc1 = dt_trans_stop(env, dt, th);
 329         if (rc == 0)
 330                 rc = rc1;
 331         if (rc1 < 0) {
 332                 mutex_lock(&loghandle->lgh_hdr_mutex);
 333                 if (subtract_count)
 334                         loghandle->lgh_hdr->llh_count += num;
 335                 for (i = i - 1; i >= 0; i--)
 336                         set_bit_le(index[i], LLOG_HDR_BITMAP(llh));
 337                 mutex_unlock(&loghandle->lgh_hdr_mutex);
 338         }
 339         RETURN(rc);
 340 }
 341
 342 int llog_cancel_rec(const struct lu_env *env, struct llog_handle *loghandle,
 343                     int index)
 344 {
 345         return llog_cancel_arr_rec(env, loghandle, 1, &index);
 346 }
 347
 348 int llog_read_header(const struct lu_env *env, struct llog_handle *handle,
 349                      const struct obd_uuid *uuid)
 350 {
 351         const struct llog_operations *lop;
 352         int rc;
 353         ENTRY;
 354
 355         rc = llog_handle2ops(handle, &lop);
 356         if (rc)
 357                 RETURN(rc);
 358
 359         if (lop->lop_read_header == NULL)
 360                 RETURN(-EOPNOTSUPP);
 361
 362         rc = lop->lop_read_header(env, handle);
 363         if (rc == LLOG_EEMPTY) {
 364                 struct llog_log_hdr *llh = handle->lgh_hdr;
 365
 366                 /* lrh_len should be initialized in llog_init_handle */
 367                 handle->lgh_last_idx = 0; /* header is record with index 0 */
 368                 llh->llh_count = 1;         /* for the header record */
 369                 llh->llh_hdr.lrh_type = LLOG_HDR_MAGIC;
 370                 LASSERT(handle->lgh_ctxt->loc_chunk_size >=
 371                                                 LLOG_MIN_CHUNK_SIZE);
 372                 llh->llh_hdr.lrh_len = handle->lgh_ctxt->loc_chunk_size;
 373                 llh->llh_hdr.lrh_index = 0;
 374                 llh->llh_timestamp = ktime_get_real_seconds();
 375                 if (uuid)
 376                         memcpy(&llh->llh_tgtuuid, uuid,
 377                                sizeof(llh->llh_tgtuuid));
 378                 llh->llh_bitmap_offset = offsetof(typeof(*llh), llh_bitmap);
 379                 /* Since update llog header might also call this function,
 380                  * let's reset the bitmap to 0 here */
 381                 memset(LLOG_HDR_BITMAP(llh), 0, llh->llh_hdr.lrh_len -
 382                                                 llh->llh_bitmap_offset -
 383                                                 sizeof(llh->llh_tail));
 384                 set_bit_le(0, LLOG_HDR_BITMAP(llh));
 385                 LLOG_HDR_TAIL(llh)->lrt_len = llh->llh_hdr.lrh_len;
 386                 LLOG_HDR_TAIL(llh)->lrt_index = llh->llh_hdr.lrh_index;
 387                 rc = 0;
 388         }
 389         RETURN(rc);
 390 }
 391 EXPORT_SYMBOL(llog_read_header);
 392
 393 int llog_init_handle(const struct lu_env *env, struct llog_handle *handle,
 394                      int flags, struct obd_uuid *uuid)
 395 {
 396         struct llog_log_hdr     *llh;
 397         enum llog_flag           fmt = flags & LLOG_F_EXT_MASK;
 398         int                      rc;
 399         int                     chunk_size = handle->lgh_ctxt->loc_chunk_size;
 400         ENTRY;
 401
 402         LASSERT(handle->lgh_hdr == NULL);
 403
 404         LASSERT(chunk_size >= LLOG_MIN_CHUNK_SIZE);
 405         OBD_ALLOC_LARGE(llh, chunk_size);
 406         if (llh == NULL)
 407                 RETURN(-ENOMEM);
 408
 409         handle->lgh_hdr = llh;
 410         handle->lgh_hdr_size = chunk_size;
 411         /* first assign flags to use llog_client_ops */
 412         llh->llh_flags = flags;
 413         rc = llog_read_header(env, handle, uuid);
 414         if (rc == 0) {
 415                 if (unlikely((llh->llh_flags & LLOG_F_IS_PLAIN &&
 416                               flags & LLOG_F_IS_CAT) ||
 417                              (llh->llh_flags & LLOG_F_IS_CAT &&
 418                               flags & LLOG_F_IS_PLAIN))) {
 419                         CERROR("%s: llog type is %s but initializing %s\n",
 420                                loghandle2name(handle),
 421                                llh->llh_flags & LLOG_F_IS_CAT ?
 422                                "catalog" : "plain",
 423                                flags & LLOG_F_IS_CAT ? "catalog" : "plain");
 424                         GOTO(out, rc = -EINVAL);
 425                 } else if (llh->llh_flags &
 426                            (LLOG_F_IS_PLAIN | LLOG_F_IS_CAT)) {
 427                         /*
 428                          * it is possible to open llog without specifying llog
 429                          * type so it is taken from llh_flags
 430                          */
 431                         flags = llh->llh_flags;
 432                 } else {
 433                         /* for some reason the llh_flags has no type set */
 434                         CERROR("llog type is not specified!\n");
 435                         GOTO(out, rc = -EINVAL);
 436                 }
 437                 if (unlikely(uuid &&
 438                              !obd_uuid_equals(uuid, &llh->llh_tgtuuid))) {
 439                         CERROR("%s: llog uuid mismatch: %s/%s\n",
 440                                loghandle2name(handle),
 441                                (char *)uuid->uuid,
 442                                (char *)llh->llh_tgtuuid.uuid);
 443                         GOTO(out, rc = -EEXIST);
 444                 }
 445         }
 446         if (flags & LLOG_F_IS_CAT) {
 447                 LASSERT(list_empty(&handle->u.chd.chd_head));
 448                 INIT_LIST_HEAD(&handle->u.chd.chd_head);
 449                 llh->llh_size = sizeof(struct llog_logid_rec);
 450                 llh->llh_flags |= LLOG_F_IS_FIXSIZE;
 451         } else if (!(flags & LLOG_F_IS_PLAIN)) {
 452                 CERROR("%s: unknown flags: %#x (expected %#x or %#x)\n",
 453                        loghandle2name(handle), flags, LLOG_F_IS_CAT,
 454                        LLOG_F_IS_PLAIN);
 455                 rc = -EINVAL;
 456         }
 457         llh->llh_flags |= fmt;
 458 out:
 459         if (rc) {
 460                 OBD_FREE_LARGE(llh, chunk_size);
 461                 handle->lgh_hdr = NULL;
 462         }
 463         RETURN(rc);
 464 }
 465 EXPORT_SYMBOL(llog_init_handle);
 466
 467 int llog_verify_record(const struct llog_handle *llh, struct llog_rec_hdr *rec)
 468 {
 469         int chunk_size = llh->lgh_hdr->llh_hdr.lrh_len;
 470
 471         if (rec->lrh_len == 0 || rec->lrh_len > chunk_size) {
 472                 CERROR("%s: record is too large: %d > %d\n",
 473                        loghandle2name(llh), rec->lrh_len, chunk_size);
 474                 return -EINVAL;
 475         }
 476         if (rec->lrh_index >= LLOG_HDR_BITMAP_SIZE(llh->lgh_hdr)) {
 477                 CERROR("%s: index is too high: %d\n",
 478                        loghandle2name(llh), rec->lrh_index);
 479                 return -EINVAL;
 480         }
 481         if ((rec->lrh_type & LLOG_OP_MASK) != LLOG_OP_MAGIC) {
 482                 CERROR("%s: magic %x is bad\n",
 483                        loghandle2name(llh), rec->lrh_type);
 484                 return -EINVAL;
 485         }
 486
 487         return 0;
 488 }
 489 EXPORT_SYMBOL(llog_verify_record);
 490
 491 static inline bool llog_is_index_skipable(int idx, struct llog_log_hdr *llh,
 492                                           struct llog_process_cat_data *cd)
 493 {
 494         if (cd && (cd->lpcd_read_mode & LLOG_READ_MODE_RAW))
 495                 return false;
 496
 497         return !test_bit_le(idx, LLOG_HDR_BITMAP(llh));
 498 }
 499
 500 static int llog_process_thread(void *arg)
 501 {
 502         struct llog_process_info        *lpi = arg;
 503         struct llog_handle              *loghandle = lpi->lpi_loghandle;
 504         struct llog_log_hdr             *llh = loghandle->lgh_hdr;
 505         struct llog_process_cat_data    *cd  = lpi->lpi_catdata;
 506         struct llog_thread_info         *lti;
 507         char                            *buf;
 508         size_t                           chunk_size;
 509         __u64                            cur_offset;
 510         int                              rc = 0, index = 1, last_index;
 511         int                              saved_index = 0;
 512         int                              last_called_index = 0;
 513         bool                             repeated = false;
 514         bool                            refresh_idx = false;
 515
 516         ENTRY;
 517
 518         if (llh == NULL)
 519                 RETURN(-EINVAL);
 520
 521         lti = lpi->lpi_env == NULL ? NULL : llog_info(lpi->lpi_env);
 522
 523         cur_offset = chunk_size = llh->llh_hdr.lrh_len;
 524         /* expect chunk_size to be power of two */
 525         LASSERT(is_power_of_2(chunk_size));
 526
 527         OBD_ALLOC_LARGE(buf, chunk_size);
 528         if (buf == NULL) {
 529                 lpi->lpi_rc = -ENOMEM;
 530                 RETURN(0);
 531         }
 532
 533         if (cd != NULL) {
 534                 last_called_index = cd->lpcd_first_idx;
 535                 index = cd->lpcd_first_idx + 1;
 536         }
 537         if (cd && cd->lpcd_last_idx)
 538                 last_index = cd->lpcd_last_idx;
 539         else if (cd && (cd->lpcd_read_mode & LLOG_READ_MODE_RAW))
 540                 last_index = loghandle->lgh_last_idx;
 541         else
 542                 last_index = LLOG_HDR_BITMAP_SIZE(llh) - 1;
 543
 544         while (rc == 0) {
 545                 struct llog_rec_hdr *rec;
 546                 off_t chunk_offset = 0;
 547                 unsigned int buf_offset = 0;
 548                 int     lh_last_idx;
 549                 int     synced_idx = 0;
 550
 551                 /* skip records not set in bitmap */
 552                 while (index <= last_index &&
 553                        llog_is_index_skipable(index, llh, cd))
 554                         ++index;
 555
 556                 /* There are no indices prior the last_index */
 557                 if (index > last_index)
 558                         break;
 559
 560                 CDEBUG(D_OTHER, "index: %d last_index %d\n", index,
 561                        last_index);
 562
 563 repeat:
 564                 /* get the buf with our target record; avoid old garbage */
 565                 memset(buf, 0, chunk_size);
 566                 /* the record index for outdated chunk data */
 567                 /* it is safe to process buffer until saved lgh_last_idx */
 568                 lh_last_idx = LLOG_HDR_TAIL(llh)->lrt_index;
 569                 rc = llog_next_block(lpi->lpi_env, loghandle, &saved_index,
 570                                      index, &cur_offset, buf, chunk_size);
 571                 if (repeated && rc)
 572                         CDEBUG(D_OTHER, "cur_offset %llu, chunk_offset %llu,"
 573                                " buf_offset %u, rc = %d\n", cur_offset,
 574                                (__u64)chunk_offset, buf_offset, rc);
 575                 if (rc == -ESTALE)
 576                         GOTO(out, rc = 0);
 577                 /* we`ve tried to reread the chunk, but there is no
 578                  * new records */
 579                 if (rc == -EIO && repeated && (chunk_offset + buf_offset) ==
 580                     cur_offset)
 581                         GOTO(out, rc = 0);
 582                 if (rc != 0)
 583                         GOTO(out, rc);
 584
 585                 /* NB: after llog_next_block() call the cur_offset is the
 586                  * offset of the next block after read one.
 587                  * The absolute offset of the current chunk is calculated
 588                  * from cur_offset value and stored in chunk_offset variable.
 589                  */
 590                 if ((cur_offset & (chunk_size - 1)) != 0)
 591                         chunk_offset = cur_offset & ~(chunk_size - 1);
 592                 else
 593                         chunk_offset = cur_offset - chunk_size;
 594
 595                 /* NB: when rec->lrh_len is accessed it is already swabbed
 596                  * since it is used at the "end" of the loop and the rec
 597                  * swabbing is done at the beginning of the loop. */
 598                 for (rec = (struct llog_rec_hdr *)(buf + buf_offset);
 599                      (char *)rec < buf + chunk_size;
 600                      rec = llog_rec_hdr_next(rec)) {
 601
 602                         CDEBUG(D_OTHER, "processing rec 0x%p type %#x\n",
 603                                rec, rec->lrh_type);
 604
 605                         if (LLOG_REC_HDR_NEEDS_SWABBING(rec))
 606                                 lustre_swab_llog_rec(rec);
 607
 608                         CDEBUG(D_OTHER, "after swabbing, type=%#x idx=%d\n",
 609                                rec->lrh_type, rec->lrh_index);
 610
 611                         if (index == (synced_idx + 1) &&
 612                             synced_idx == LLOG_HDR_TAIL(llh)->lrt_index)
 613                                 GOTO(out, rc = 0);
 614
 615                         if (OBD_FAIL_PRECHECK(OBD_FAIL_LLOG_PROCESS_TIMEOUT) &&
 616                                 cfs_fail_val == (unsigned int)
 617                                         (loghandle->lgh_id.lgl_oi.oi.oi_id &
 618                                          0xFFFFFFFF)) {
 619                                 OBD_RACE(OBD_FAIL_LLOG_PROCESS_TIMEOUT);
 620                         }
 621
 622                         /* the bitmap could be changed during processing
 623                          * records from the chunk. For wrapped catalog
 624                          * it means we can read deleted record and try to
 625                          * process it. Check this case and reread the chunk.
 626                          * It is safe to process to lh_last_idx, including
 627                          * lh_last_idx if it was synced. We can not do <=
 628                          * comparison, cause for wrapped catalog lgh_last_idx
 629                          * could be less than index. So we detect last index
 630                          * for processing as index == lh_last_idx+1. But when
 631                          * catalog is wrapped and full lgh_last_idx=llh_cat_idx,
 632                          * the first processing index is llh_cat_idx+1.The
 633                          * exception is !(lgh_last_idx == llh_cat_idx &&
 634                          * index == llh_cat_idx + 1), and after simplification
 635                          * it turns to
 636                          * lh_last_idx != LLOG_HDR_TAIL(llh)->lrt_index
 637                          * This exception is working for catalog only.
 638                          */
 639
 640                         if ((index == lh_last_idx && synced_idx != index) ||
 641                             (index == (lh_last_idx + 1) &&
 642                              lh_last_idx != LLOG_HDR_TAIL(llh)->lrt_index) ||
 643                             (rec->lrh_index == 0 && !repeated)) {
 644
 645                                 /* save offset inside buffer for the re-read */
 646                                 buf_offset = (char *)rec - (char *)buf;
 647                                 cur_offset = chunk_offset;
 648                                 repeated = true;
 649                                 /* We need to be sure lgh_last_idx
 650                                  * record was saved to disk
 651                                  */
 652                                 down_read(&loghandle->lgh_last_sem);
 653                                 synced_idx = LLOG_HDR_TAIL(llh)->lrt_index;
 654                                 up_read(&loghandle->lgh_last_sem);
 655                                 CDEBUG(D_OTHER, "synced_idx: %d\n", synced_idx);
 656                                 goto repeat;
 657
 658                         }
 659
 660                         repeated = false;
 661
 662                         rc = llog_verify_record(loghandle, rec);
 663                         if (rc) {
 664                                 CERROR("%s: invalid record in llog "DFID
 665                                        " record for index %d/%d: rc = %d\n",
 666                                        loghandle2name(loghandle),
 667                                        PFID(&loghandle->lgh_id.lgl_oi.oi_fid),
 668                                        rec->lrh_index, index, rc);
 669                                 /*
 670                                  * the block seem to be corrupted, let's try
 671                                  * with the next one. reset rc to go to the
 672                                  * next chunk.
 673                                  */
 674                                 refresh_idx = true;
 675                                 index = 0;
 676                                 GOTO(repeat, rc = 0);
 677                         }
 678
 679                         if (rec->lrh_index < index) {
 680                                 CDEBUG(D_OTHER, "skipping lrh_index %d\n",
 681                                        rec->lrh_index);
 682                                 continue;
 683                         }
 684
 685                         if (rec->lrh_index > index) {
 686                                 /* the record itself looks good, but we met a
 687                                  * gap which can be result of old bugs, just
 688                                  * keep going */
 689                                 CERROR("%s: "DFID" index %u, expected %u\n",
 690                                        loghandle2name(loghandle),
 691                                        PFID(&loghandle->lgh_id.lgl_oi.oi_fid),
 692                                        rec->lrh_index, index);
 693                                 index = rec->lrh_index;
 694                         }
 695
 696                         CDEBUG(D_OTHER,
 697                                "lrh_index: %d lrh_len: %d (%d remains)\n",
 698                                rec->lrh_index, rec->lrh_len,
 699                                (int)(buf + chunk_size - (char *)rec));
 700
 701                         /* lgh_cur_offset is used only at llog_test_3 */
 702                         loghandle->lgh_cur_offset = (char *)rec - (char *)buf +
 703                                                     chunk_offset;
 704
 705                         /* if needed, process the callback on this record */
 706                         if (!llog_is_index_skipable(index, llh, cd)) {
 707                                 struct llog_cookie *lgc;
 708                                 __u64   tmp_off;
 709                                 int     tmp_idx;
 710
 711                                 CDEBUG((llh->llh_flags & LLOG_F_IS_CAT ?
 712                                         D_HA : D_OTHER),
 713                                        "index: %d, lh_last_idx: %d "
 714                                        "synced_idx: %d lgh_last_idx: %d\n",
 715                                        index, lh_last_idx, synced_idx,
 716                                        loghandle->lgh_last_idx);
 717
 718                                 if (lti != NULL) {
 719                                         lgc = &lti->lgi_cookie;
 720                                         /* store lu_env for recursive calls */
 721                                         tmp_off = lgc->lgc_offset;
 722                                         tmp_idx = lgc->lgc_index;
 723
 724                                         lgc->lgc_offset = (char *)rec -
 725                                                 (char *)buf + chunk_offset;
 726                                         lgc->lgc_index = rec->lrh_index;
 727                                 }
 728                                 /* using lu_env for passing record offset to
 729                                  * llog_write through various callbacks */
 730                                 rc = lpi->lpi_cb(lpi->lpi_env, loghandle, rec,
 731                                                  lpi->lpi_cbdata);
 732                                 last_called_index = index;
 733
 734                                 if (lti != NULL) {
 735                                         lgc->lgc_offset = tmp_off;
 736                                         lgc->lgc_index = tmp_idx;
 737                                 }
 738
 739                                 if (rc == LLOG_PROC_BREAK ||
 740                                     rc == LLOG_SKIP_PLAIN) {
 741                                         GOTO(out, rc);
 742                                 } else if (rc == LLOG_DEL_RECORD) {
 743                                         rc = llog_cancel_rec(lpi->lpi_env,
 744                                                              loghandle,
 745                                                              rec->lrh_index);
 746                                         /* Allow parallel cancelling, ENOENT
 747                                          * means record was canceled at another
 748                                          * processing thread or callback
 749                                          */
 750                                         if (rc == -ENOENT)
 751                                                 rc = 0;
 752                                 }
 753                                 if (rc)
 754                                         GOTO(out, rc);
 755                                 /* some stupid callbacks directly cancel records
 756                                  * and delete llog. Check it and stop
 757                                  * processing. */
 758                                 if (loghandle->lgh_hdr == NULL ||
 759                                     loghandle->lgh_hdr->llh_count == 1)
 760                                         GOTO(out, rc = 0);
 761                         }
 762                         /* exit if the last index is reached */
 763                         if (index >= last_index)
 764                                 GOTO(out, rc = 0);
 765                         ++index;
 766                 }
 767         }
 768
 769 out:
 770         CDEBUG(D_HA, "stop processing %s "DOSTID":%x index %d count %d\n",
 771                ((llh->llh_flags & LLOG_F_IS_CAT) ? "catalog" : "plain"),
 772                POSTID(&loghandle->lgh_id.lgl_oi), loghandle->lgh_id.lgl_ogen,
 773                index, llh->llh_count);
 774
 775         if (cd != NULL)
 776                 cd->lpcd_last_idx = last_called_index;
 777
 778         if (unlikely(rc == -EIO && loghandle->lgh_obj != NULL)) {
 779                 if (dt_object_remote(loghandle->lgh_obj)) {
 780                         /* If it is remote object, then -EIO might means
 781                          * disconnection or eviction, let's return -EAGAIN,
 782                          * so for update recovery log processing, it will
 783                          * retry until the umount or abort recovery, see
 784                          * lod_sub_recovery_thread() */
 785                         CERROR("%s retry remote llog process\n",
 786                                loghandle2name(loghandle));
 787                         rc = -EAGAIN;
 788                 } else {
 789                         /* something bad happened to the processing of a local
 790                          * llog file, probably I/O error or the log got
 791                          * corrupted to be able to finally release the log we
 792                          * discard any remaining bits in the header */
 793                         CERROR("%s: Local llog found corrupted #"DOSTID":%x"
 794                                " %s index %d count %d\n",
 795                                loghandle2name(loghandle),
 796                                POSTID(&loghandle->lgh_id.lgl_oi),
 797                                loghandle->lgh_id.lgl_ogen,
 798                                ((llh->llh_flags & LLOG_F_IS_CAT) ? "catalog" :
 799                                 "plain"), index, llh->llh_count);
 800
 801                         while (index <= last_index) {
 802                                 if (test_bit_le(index,
 803                                                   LLOG_HDR_BITMAP(llh)) != 0)
 804                                         llog_cancel_rec(lpi->lpi_env, loghandle,
 805                                                         index);
 806                                 index++;
 807                         }
 808                         rc = 0;
 809                 }
 810         }
 811
 812         OBD_FREE_LARGE(buf, chunk_size);
 813         lpi->lpi_rc = rc;
 814         return 0;
 815 }
 816
 817 static int llog_process_thread_daemonize(void *arg)
 818 {
 819         struct llog_process_info        *lpi = arg;
 820         struct lu_env                    env;
 821         int                              rc;
 822         struct nsproxy                  *new_ns, *curr_ns = current->nsproxy;
 823
 824         task_lock(lpi->lpi_reftask);
 825         new_ns = lpi->lpi_reftask->nsproxy;
 826         if (curr_ns != new_ns) {
 827                 get_nsproxy(new_ns);
 828
 829                 current->nsproxy = new_ns;
 830                 /* XXX: we should call put_nsproxy() instead of
 831                  * atomic_dec(&ns->count) directly. But put_nsproxy() cannot be
 832                  * used outside of the kernel itself, because it calls
 833                  * free_nsproxy() which is not exported by the kernel
 834                  * (defined in kernel/nsproxy.c) */
 835                 if (curr_ns)
 836                         atomic_dec(&curr_ns->count);
 837         }
 838         task_unlock(lpi->lpi_reftask);
 839
 840         unshare_fs_struct();
 841         /* client env has no keys, tags is just 0 */
 842         rc = lu_env_init(&env, LCT_LOCAL | LCT_MG_THREAD);
 843         if (rc)
 844                 goto out;
 845         lpi->lpi_env = &env;
 846
 847         rc = llog_process_thread(arg);
 848
 849         lu_env_fini(&env);
 850 out:
 851         complete(&lpi->lpi_completion);
 852         return rc;
 853 }
 854
 855 int llog_process_or_fork(const struct lu_env *env,
 856                          struct llog_handle *loghandle,
 857                          llog_cb_t cb, void *data, void *catdata, bool fork)
 858 {
 859         struct llog_process_info *lpi;
 860         struct llog_process_data *d = data;
 861         struct llog_process_cat_data *cd = catdata;
 862         __u32 flags = loghandle->lgh_hdr->llh_flags;
 863         int rc;
 864
 865         ENTRY;
 866
 867         OBD_ALLOC_PTR(lpi);
 868         if (lpi == NULL) {
 869                 CERROR("cannot alloc pointer\n");
 870                 RETURN(-ENOMEM);
 871         }
 872         lpi->lpi_loghandle = loghandle;
 873         lpi->lpi_cb        = cb;
 874         lpi->lpi_cbdata    = data;
 875         lpi->lpi_catdata   = catdata;
 876
 877         CDEBUG(D_OTHER, "Processing "DFID" flags 0x%03x startcat %d startidx %d first_idx %d last_idx %d read_mode %d\n",
 878                PFID(&loghandle->lgh_id.lgl_oi.oi_fid), flags,
 879                (flags & LLOG_F_IS_CAT) && d ? d->lpd_startcat : -1,
 880                (flags & LLOG_F_IS_CAT) && d ? d->lpd_startidx : -1,
 881                cd ? cd->lpcd_first_idx : -1, cd ? cd->lpcd_last_idx : -1,
 882                cd ? cd->lpcd_read_mode : -1);
 883         if (fork) {
 884                 struct task_struct *task;
 885
 886                 /* The new thread can't use parent env,
 887                  * init the new one in llog_process_thread_daemonize. */
 888                 lpi->lpi_env = NULL;
 889                 init_completion(&lpi->lpi_completion);
 890                 /* take reference to current, so that
 891                  * llog_process_thread_daemonize() can use it to switch to
 892                  * namespace associated with current  */
 893                 lpi->lpi_reftask = current;
 894                 task = kthread_run(llog_process_thread_daemonize, lpi,
 895                                    "llog_process_thread");
 896                 if (IS_ERR(task)) {
 897                         rc = PTR_ERR(task);
 898                         CERROR("%s: cannot start thread: rc = %d\n",
 899                                loghandle2name(loghandle), rc);
 900                         GOTO(out_lpi, rc);
 901                 }
 902                 wait_for_completion(&lpi->lpi_completion);
 903         } else {
 904                 lpi->lpi_env = env;
 905                 llog_process_thread(lpi);
 906         }
 907         rc = lpi->lpi_rc;
 908
 909 out_lpi:
 910         OBD_FREE_PTR(lpi);
 911         RETURN(rc);
 912 }
 913 EXPORT_SYMBOL(llog_process_or_fork);
 914
 915 int llog_process(const struct lu_env *env, struct llog_handle *loghandle,
 916                  llog_cb_t cb, void *data, void *catdata)
 917 {
 918         int rc;
 919         rc = llog_process_or_fork(env, loghandle, cb, data, catdata, true);
 920         return rc == LLOG_DEL_PLAIN ? 0 : rc;
 921 }
 922 EXPORT_SYMBOL(llog_process);
 923
 924 static inline const struct cred *llog_raise_resource(void)
 925 {
 926         struct cred *cred = NULL;
 927
 928         if (cap_raised(current_cap(), CAP_SYS_RESOURCE))
 929                 return cred;
 930
 931         cred = prepare_creds();
 932         if (!cred)
 933                 return cred;
 934
 935         cap_raise(cred->cap_effective, CAP_SYS_RESOURCE);
 936         return override_creds(cred);
 937 }
 938
 939 static inline void llog_restore_resource(const struct cred *old_cred)
 940 {
 941         if (old_cred)
 942                 revert_creds(old_cred);
 943 }
 944
 945 int llog_reverse_process(const struct lu_env *env,
 946                          struct llog_handle *loghandle, llog_cb_t cb,
 947                          void *data, void *catdata)
 948 {
 949         struct llog_log_hdr *llh = loghandle->lgh_hdr;
 950         struct llog_process_cat_data *cd = catdata;
 951         void *buf;
 952         int rc = 0, first_index = 1, index, idx;
 953         __u32   chunk_size = llh->llh_hdr.lrh_len;
 954         ENTRY;
 955
 956         OBD_ALLOC_LARGE(buf, chunk_size);
 957         if (buf == NULL)
 958                 RETURN(-ENOMEM);
 959
 960         if (cd != NULL)
 961                 first_index = cd->lpcd_first_idx + 1;
 962         if (cd != NULL && cd->lpcd_last_idx)
 963                 index = cd->lpcd_last_idx;
 964         else
 965                 index = LLOG_HDR_BITMAP_SIZE(llh) - 1;
 966
 967         while (rc == 0) {
 968                 struct llog_rec_hdr *rec;
 969                 struct llog_rec_tail *tail;
 970
 971                 /* skip records not set in bitmap */
 972                 while (index >= first_index &&
 973                        llog_is_index_skipable(index, llh, cd))
 974                         --index;
 975
 976                 LASSERT(index >= first_index - 1);
 977                 if (index == first_index - 1)
 978                         break;
 979
 980                 /* get the buf with our target record; avoid old garbage */
 981                 memset(buf, 0, chunk_size);
 982                 rc = llog_prev_block(env, loghandle, index, buf, chunk_size);
 983                 if (rc)
 984                         GOTO(out, rc);
 985
 986                 rec = buf;
 987                 idx = rec->lrh_index;
 988                 CDEBUG(D_RPCTRACE, "index %u : idx %u\n", index, idx);
 989                 while (idx < index) {
 990                         rec = (void *)rec + rec->lrh_len;
 991                         if (LLOG_REC_HDR_NEEDS_SWABBING(rec))
 992                                 lustre_swab_llog_rec(rec);
 993                         idx ++;
 994                 }
 995                 LASSERT(idx == index);
 996                 tail = (void *)rec + rec->lrh_len - sizeof(*tail);
 997
 998                 /* process records in buffer, starting where we found one */
 999                 while ((void *)tail > buf) {
1000                         if (tail->lrt_index == 0)
1001                                 GOTO(out, rc = 0); /* no more records */
1002
1003                         /* if needed, process the callback on this record */
1004                         if (!llog_is_index_skipable(index, llh, cd)) {
1005                                 rec = (void *)tail - tail->lrt_len +
1006                                       sizeof(*tail);
1007
1008                                 rc = cb(env, loghandle, rec, data);
1009                                 if (rc == LLOG_PROC_BREAK ||
1010                                     rc == LLOG_SKIP_PLAIN) {
1011                                         GOTO(out, rc);
1012                                 } else if (rc == LLOG_DEL_RECORD) {
1013                                         rc = llog_cancel_rec(env, loghandle,
1014                                                              tail->lrt_index);
1015                                 }
1016                                 if (rc)
1017                                         GOTO(out, rc);
1018                         }
1019
1020                         /* previous record, still in buffer? */
1021                         --index;
1022                         if (index < first_index)
1023                                 GOTO(out, rc = 0);
1024                         tail = (void *)tail - tail->lrt_len;
1025                 }
1026         }
1027
1028 out:
1029         if (buf != NULL)
1030                 OBD_FREE_LARGE(buf, chunk_size);
1031         RETURN(rc);
1032 }
1033 EXPORT_SYMBOL(llog_reverse_process);
1034
1035 /**
1036  * new llog API
1037  *
1038  * API functions:
1039  *      llog_open - open llog, may not exist
1040  *      llog_exist - check if llog exists
1041  *      llog_close - close opened llog, pair for open, frees llog_handle
1042  *      llog_declare_create - declare llog creation
1043  *      llog_create - create new llog on disk, need transaction handle
1044  *      llog_declare_write_rec - declaration of llog write
1045  *      llog_write_rec - write llog record on disk, need transaction handle
1046  *      llog_declare_add - declare llog catalog record addition
1047  *      llog_add - add llog record in catalog, need transaction handle
1048  */
1049 int llog_exist(struct llog_handle *loghandle)
1050 {
1051         const struct llog_operations *lop;
1052         int rc;
1053
1054         ENTRY;
1055
1056         rc = llog_handle2ops(loghandle, &lop);
1057         if (rc)
1058                 RETURN(rc);
1059         if (lop->lop_exist == NULL)
1060                 RETURN(-EOPNOTSUPP);
1061
1062         rc = lop->lop_exist(loghandle);
1063         RETURN(rc);
1064 }
1065 EXPORT_SYMBOL(llog_exist);
1066
1067 int llog_declare_create(const struct lu_env *env,
1068                         struct llog_handle *loghandle, struct thandle *th)
1069 {
1070         const struct cred *old_cred;
1071         const struct llog_operations *lop;
1072         int rc;
1073
1074         ENTRY;
1075
1076         rc = llog_handle2ops(loghandle, &lop);
1077         if (rc)
1078                 RETURN(rc);
1079         if (lop->lop_declare_create == NULL)
1080                 RETURN(-EOPNOTSUPP);
1081
1082         old_cred = llog_raise_resource();
1083         rc = lop->lop_declare_create(env, loghandle, th);
1084         llog_restore_resource(old_cred);
1085         RETURN(rc);
1086 }
1087
1088 int llog_create(const struct lu_env *env, struct llog_handle *handle,
1089                 struct thandle *th)
1090 {
1091         const struct cred *old_cred;
1092         const struct llog_operations *lop;
1093         int rc;
1094
1095         ENTRY;
1096
1097         rc = llog_handle2ops(handle, &lop);
1098         if (rc)
1099                 RETURN(rc);
1100         if (lop->lop_create == NULL)
1101                 RETURN(-EOPNOTSUPP);
1102
1103         old_cred = llog_raise_resource();
1104         rc = lop->lop_create(env, handle, th);
1105         llog_restore_resource(old_cred);
1106         RETURN(rc);
1107 }
1108
1109 int llog_declare_write_rec(const struct lu_env *env,
1110                            struct llog_handle *handle,
1111                            struct llog_rec_hdr *rec, int idx,
1112                            struct thandle *th)
1113 {
1114         const struct cred *old_cred;
1115         const struct llog_operations *lop;
1116         int rc;
1117
1118         ENTRY;
1119
1120         rc = llog_handle2ops(handle, &lop);
1121         if (rc)
1122                 RETURN(rc);
1123         LASSERT(lop);
1124         if (lop->lop_declare_write_rec == NULL)
1125                 RETURN(-EOPNOTSUPP);
1126
1127         old_cred = llog_raise_resource();
1128         rc = lop->lop_declare_write_rec(env, handle, rec, idx, th);
1129         llog_restore_resource(old_cred);
1130         RETURN(rc);
1131 }
1132
1133 int llog_write_rec(const struct lu_env *env, struct llog_handle *handle,
1134                    struct llog_rec_hdr *rec, struct llog_cookie *logcookies,
1135                    int idx, struct thandle *th)
1136 {
1137         const struct cred *old_cred;
1138         const struct llog_operations *lop;
1139         int rc, buflen;
1140
1141         ENTRY;
1142
1143         /* API sanity checks */
1144         if (handle == NULL) {
1145                 CERROR("loghandle is missed\n");
1146                 RETURN(-EPROTO);
1147         } else if (handle->lgh_obj == NULL) {
1148                 CERROR("loghandle %p with NULL object\n",
1149                         handle);
1150                 RETURN(-EPROTO);
1151         } else if (th == NULL) {
1152                 CERROR("%s: missed transaction handle\n",
1153                        loghandle2name(handle));
1154                 RETURN(-EPROTO);
1155         } else if (handle->lgh_hdr == NULL) {
1156                 CERROR("%s: loghandle %p with no header\n",
1157                        loghandle2name(handle), handle);
1158                 RETURN(-EPROTO);
1159         }
1160
1161         rc = llog_handle2ops(handle, &lop);
1162         if (rc)
1163                 RETURN(rc);
1164
1165         if (lop->lop_write_rec == NULL)
1166                 RETURN(-EOPNOTSUPP);
1167
1168         buflen = rec->lrh_len;
1169         LASSERT(cfs_size_round(buflen) == buflen);
1170
1171         old_cred = llog_raise_resource();
1172         rc = lop->lop_write_rec(env, handle, rec, logcookies, idx, th);
1173         llog_restore_resource(old_cred);
1174         RETURN(rc);
1175 }
1176
1177 int llog_add(const struct lu_env *env, struct llog_handle *lgh,
1178              struct llog_rec_hdr *rec, struct llog_cookie *logcookies,
1179              struct thandle *th)
1180 {
1181         const struct cred *old_cred;
1182         int rc;
1183
1184         ENTRY;
1185
1186         if (lgh->lgh_logops->lop_add == NULL)
1187                 RETURN(-EOPNOTSUPP);
1188
1189         old_cred = llog_raise_resource();
1190         rc = lgh->lgh_logops->lop_add(env, lgh, rec, logcookies, th);
1191         llog_restore_resource(old_cred);
1192         RETURN(rc);
1193 }
1194 EXPORT_SYMBOL(llog_add);
1195
1196 int llog_declare_add(const struct lu_env *env, struct llog_handle *lgh,
1197                      struct llog_rec_hdr *rec, struct thandle *th)
1198 {
1199         const struct cred *old_cred;
1200         int rc;
1201
1202         ENTRY;
1203
1204         if (lgh->lgh_logops->lop_declare_add == NULL)
1205                 RETURN(-EOPNOTSUPP);
1206
1207         old_cred = llog_raise_resource();
1208         rc = lgh->lgh_logops->lop_declare_add(env, lgh, rec, th);
1209         llog_restore_resource(old_cred);
1210         RETURN(rc);
1211 }
1212 EXPORT_SYMBOL(llog_declare_add);
1213
1214 /**
1215  * Helper function to open llog or create it if doesn't exist.
1216  * It hides all transaction handling from caller.
1217  */
1218 int llog_open_create(const struct lu_env *env, struct llog_ctxt *ctxt,
1219                      struct llog_handle **res, struct llog_logid *logid,
1220                      char *name)
1221 {
1222         struct dt_device        *d;
1223         struct thandle          *th;
1224         int                      rc;
1225
1226         ENTRY;
1227
1228         rc = llog_open(env, ctxt, res, logid, name, LLOG_OPEN_NEW);
1229         if (rc)
1230                 RETURN(rc);
1231
1232         if (llog_exist(*res))
1233                 RETURN(0);
1234
1235         LASSERT((*res)->lgh_obj != NULL);
1236
1237         d = lu2dt_dev((*res)->lgh_obj->do_lu.lo_dev);
1238
1239         if (unlikely(unlikely(d->dd_rdonly)))
1240                 RETURN(-EROFS);
1241
1242         th = dt_trans_create(env, d);
1243         if (IS_ERR(th))
1244                 GOTO(out, rc = PTR_ERR(th));
1245
1246         /* Create update llog object synchronously, which
1247          * happens during inialization process see
1248          * lod_sub_prep_llog(), to make sure the update
1249          * llog object is created before corss-MDT writing
1250          * updates into the llog object */
1251         if (ctxt->loc_flags & LLOG_CTXT_FLAG_NORMAL_FID)
1252                 th->th_sync = 1;
1253
1254         th->th_wait_submit = 1;
1255         rc = llog_declare_create(env, *res, th);
1256         if (rc == 0) {
1257                 rc = dt_trans_start_local(env, d, th);
1258                 if (rc == 0)
1259                         rc = llog_create(env, *res, th);
1260         }
1261         dt_trans_stop(env, d, th);
1262 out:
1263         if (rc)
1264                 llog_close(env, *res);
1265         RETURN(rc);
1266 }
1267 EXPORT_SYMBOL(llog_open_create);
1268
1269 /**
1270  * Helper function to delete existent llog.
1271  */
1272 int llog_erase(const struct lu_env *env, struct llog_ctxt *ctxt,
1273                struct llog_logid *logid, char *name)
1274 {
1275         struct llog_handle      *handle;
1276         int                      rc = 0, rc2;
1277
1278         ENTRY;
1279
1280         /* nothing to erase */
1281         if (name == NULL && logid == NULL)
1282                 RETURN(0);
1283
1284         rc = llog_open(env, ctxt, &handle, logid, name, LLOG_OPEN_EXISTS);
1285         if (rc < 0)
1286                 RETURN(rc);
1287
1288         rc = llog_init_handle(env, handle, LLOG_F_IS_PLAIN, NULL);
1289         if (rc == 0)
1290                 rc = llog_destroy(env, handle);
1291
1292         rc2 = llog_close(env, handle);
1293         if (rc == 0)
1294                 rc = rc2;
1295         RETURN(rc);
1296 }
1297 EXPORT_SYMBOL(llog_erase);
1298
1299 /*
1300  * Helper function for write record in llog.
1301  * It hides all transaction handling from caller.
1302  * Valid only with local llog.
1303  */
1304 int llog_write(const struct lu_env *env, struct llog_handle *loghandle,
1305                struct llog_rec_hdr *rec, int idx)
1306 {
1307         struct dt_device        *dt;
1308         struct thandle          *th;
1309         bool                    need_cookie;
1310         int                     rc;
1311
1312         ENTRY;
1313
1314         LASSERT(loghandle);
1315         LASSERT(loghandle->lgh_ctxt);
1316         LASSERT(loghandle->lgh_obj != NULL);
1317
1318         dt = lu2dt_dev(loghandle->lgh_obj->do_lu.lo_dev);
1319
1320         if (unlikely(unlikely(dt->dd_rdonly)))
1321                 RETURN(-EROFS);
1322
1323         th = dt_trans_create(env, dt);
1324         if (IS_ERR(th))
1325                 RETURN(PTR_ERR(th));
1326
1327         rc = llog_declare_write_rec(env, loghandle, rec, idx, th);
1328         if (rc)
1329                 GOTO(out_trans, rc);
1330
1331         th->th_wait_submit = 1;
1332         rc = dt_trans_start_local(env, dt, th);
1333         if (rc)
1334                 GOTO(out_trans, rc);
1335
1336         need_cookie = !(idx == LLOG_HEADER_IDX || idx == LLOG_NEXT_IDX);
1337
1338         down_write(&loghandle->lgh_lock);
1339         if (need_cookie) {
1340                 struct llog_thread_info *lti = llog_info(env);
1341
1342                 /* cookie comes from llog_process_thread */
1343                 rc = llog_write_rec(env, loghandle, rec, &lti->lgi_cookie,
1344                                     rec->lrh_index, th);
1345                 /* upper layer didn`t pass cookie so change rc */
1346                 rc = (rc == 1 ? 0 : rc);
1347         } else {
1348                 rc = llog_write_rec(env, loghandle, rec, NULL, idx, th);
1349         }
1350
1351         up_write(&loghandle->lgh_lock);
1352 out_trans:
1353         dt_trans_stop(env, dt, th);
1354         RETURN(rc);
1355 }
1356 EXPORT_SYMBOL(llog_write);
1357
1358 int llog_open(const struct lu_env *env, struct llog_ctxt *ctxt,
1359               struct llog_handle **lgh, struct llog_logid *logid,
1360               char *name, enum llog_open_param open_param)
1361 {
1362         const struct cred *old_cred;
1363         int      rc;
1364
1365         ENTRY;
1366
1367         LASSERT(ctxt);
1368         LASSERT(ctxt->loc_logops);
1369
1370         if (ctxt->loc_logops->lop_open == NULL) {
1371                 *lgh = NULL;
1372                 RETURN(-EOPNOTSUPP);
1373         }
1374
1375         *lgh = llog_alloc_handle();
1376         if (*lgh == NULL)
1377                 RETURN(-ENOMEM);
1378         (*lgh)->lgh_ctxt = ctxt;
1379         (*lgh)->lgh_logops = ctxt->loc_logops;
1380
1381         old_cred = llog_raise_resource();
1382         rc = ctxt->loc_logops->lop_open(env, *lgh, logid, name, open_param);
1383         llog_restore_resource(old_cred);
1384         if (rc) {
1385                 llog_free_handle(*lgh);
1386                 *lgh = NULL;
1387         }
1388         RETURN(rc);
1389 }
1390 EXPORT_SYMBOL(llog_open);
1391
1392 int llog_close(const struct lu_env *env, struct llog_handle *loghandle)
1393 {
1394         return llog_handle_put(env, loghandle);
1395 }
1396 EXPORT_SYMBOL(llog_close);
1397
1398 /**
1399  * Helper function to get the llog size in records. It is used by MGS
1400  * mostly to check that config llog exists and contains data.
1401  *
1402  * \param[in] env       execution environment
1403  * \param[in] ctxt      llog context
1404  * \param[in] name      llog name
1405  *
1406  * \retval              true if there are records in llog besides a header
1407  * \retval              false on error or llog without records
1408  */
1409 int llog_is_empty(const struct lu_env *env, struct llog_ctxt *ctxt,
1410                   char *name)
1411 {
1412         struct llog_handle      *llh;
1413         int                      rc = 0;
1414
1415         rc = llog_open(env, ctxt, &llh, NULL, name, LLOG_OPEN_EXISTS);
1416         if (rc < 0) {
1417                 if (likely(rc == -ENOENT))
1418                         rc = 0;
1419                 GOTO(out, rc);
1420         }
1421
1422         rc = llog_init_handle(env, llh, LLOG_F_IS_PLAIN, NULL);
1423         if (rc)
1424                 GOTO(out_close, rc);
1425         rc = llog_get_size(llh);
1426
1427 out_close:
1428         llog_close(env, llh);
1429 out:
1430         /* The header is record 1, the llog is still considered as empty
1431          * if there is only header */
1432         return (rc <= 1);
1433 }
1434 EXPORT_SYMBOL(llog_is_empty);
1435
1436 /* this callback run in raw read mode (canceled record are processed) */
1437 int llog_copy_handler(const struct lu_env *env, struct llog_handle *llh,
1438                       struct llog_rec_hdr *rec, void *data)
1439 {
1440         struct llog_handle *copy_llh = data;
1441         int idx = rec->lrh_index;
1442         int rc;
1443
1444         ENTRY;
1445
1446         /* Append all records */
1447         rc = llog_write(env, copy_llh, rec, LLOG_NEXT_IDX);
1448
1449         /* Cancel the record if it is canceled on the source */
1450         if (!rc && !test_bit_le(idx, LLOG_HDR_BITMAP(llh->lgh_hdr)))
1451                 rc = llog_cancel_rec(env, copy_llh, copy_llh->lgh_last_idx);
1452
1453         RETURN(rc);
1454 }
1455
1456 /* backup plain llog */
1457 int llog_backup(const struct lu_env *env, struct obd_device *obd,
1458                 struct llog_ctxt *ctxt, struct llog_ctxt *bctxt,
1459                 char *name, char *backup)
1460 {
1461         struct llog_handle *llh, *bllh;
1462         struct llog_process_cat_data cd = {0};
1463         int rc;
1464
1465         ENTRY;
1466
1467         /* open original log */
1468         rc = llog_open(env, ctxt, &llh, NULL, name, LLOG_OPEN_EXISTS);
1469         if (rc < 0) {
1470                 /* the -ENOENT case is also reported to the caller
1471                  * but silently so it should handle that if needed.
1472                  */
1473                 if (rc != -ENOENT)
1474                         CERROR("%s: failed to open log %s: rc = %d\n",
1475                                obd->obd_name, name, rc);
1476                 RETURN(rc);
1477         }
1478
1479         rc = llog_init_handle(env, llh, LLOG_F_IS_PLAIN, NULL);
1480         if (rc)
1481                 GOTO(out_close, rc);
1482
1483         /* Make sure there's no old backup log */
1484         rc = llog_erase(env, bctxt, NULL, backup);
1485         if (rc < 0 && rc != -ENOENT)
1486                 GOTO(out_close, rc);
1487
1488         /* open backup log */
1489         rc = llog_open_create(env, bctxt, &bllh, NULL, backup);
1490         if (rc) {
1491                 CERROR("%s: failed to open backup logfile %s: rc = %d\n",
1492                        obd->obd_name, backup, rc);
1493                 GOTO(out_close, rc);
1494         }
1495
1496         /* check that backup llog is not the same object as original one */
1497         if (llh->lgh_obj == bllh->lgh_obj) {
1498                 CERROR("%s: backup llog %s to itself (%s), objects %p/%p\n",
1499                        obd->obd_name, name, backup, llh->lgh_obj,
1500                        bllh->lgh_obj);
1501                 GOTO(out_backup, rc = -EEXIST);
1502         }
1503
1504         rc = llog_init_handle(env, bllh, LLOG_F_IS_PLAIN, NULL);
1505         if (rc)
1506                 GOTO(out_backup, rc);
1507
1508         /* Read canceled records to have an exact copy */
1509         cd.lpcd_read_mode = LLOG_READ_MODE_RAW;
1510         /* Copy log record by record */
1511         rc = llog_process_or_fork(env, llh, llog_copy_handler, (void *)bllh,
1512                                   &cd, false);
1513         if (rc)
1514                 CERROR("%s: failed to backup log %s: rc = %d\n",
1515                        obd->obd_name, name, rc);
1516 out_backup:
1517         llog_close(env, bllh);
1518 out_close:
1519         llog_close(env, llh);
1520         RETURN(rc);
1521 }
1522 EXPORT_SYMBOL(llog_backup);
1523
1524 /* Get size of llog */
1525 __u64 llog_size(const struct lu_env *env, struct llog_handle *llh)
1526 {
1527         int rc;
1528         struct lu_attr la;
1529
1530         rc = llh->lgh_obj->do_ops->do_attr_get(env, llh->lgh_obj, &la);
1531         if (rc) {
1532                 CERROR("%s: attr_get failed for "DFID": rc = %d\n",
1533                        loghandle2name(llh), PFID(&llh->lgh_id.lgl_oi.oi_fid),
1534                        rc);
1535                 return 0;
1536         }
1537
1538         return la.la_size;
1539 }
1540 EXPORT_SYMBOL(llog_size);
1541