lib/tdb/common/transaction.c

   1  /*
   2    Unix SMB/CIFS implementation.
   3
   4    trivial database library
   5
   6    Copyright (C) Andrew Tridgell              2005
   7
   8      ** NOTE! The following LGPL license applies to the tdb
   9      ** library. This does NOT imply that all of Samba is released
  10      ** under the LGPL
  11
  12    This library is free software; you can redistribute it and/or
  13    modify it under the terms of the GNU Lesser General Public
  14    License as published by the Free Software Foundation; either
  15    version 3 of the License, or (at your option) any later version.
  16
  17    This library is distributed in the hope that it will be useful,
  18    but WITHOUT ANY WARRANTY; without even the implied warranty of
  19    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  20    Lesser General Public License for more details.
  21
  22    You should have received a copy of the GNU Lesser General Public
  23    License along with this library; if not, see <http://www.gnu.org/licenses/>.
  24 */
  25
  26 #include "tdb_private.h"
  27
  28 /*
  29   transaction design:
  30
  31   - only allow a single transaction at a time per database. This makes
  32     using the transaction API simpler, as otherwise the caller would
  33     have to cope with temporary failures in transactions that conflict
  34     with other current transactions
  35
  36   - keep the transaction recovery information in the same file as the
  37     database, using a special 'transaction recovery' record pointed at
  38     by the header. This removes the need for extra journal files as
  39     used by some other databases
  40
  41   - dynamically allocated the transaction recover record, re-using it
  42     for subsequent transactions. If a larger record is needed then
  43     tdb_free() the old record to place it on the normal tdb freelist
  44     before allocating the new record
  45
  46   - during transactions, keep a linked list of writes all that have
  47     been performed by intercepting all tdb_write() calls. The hooked
  48     transaction versions of tdb_read() and tdb_write() check this
  49     linked list and try to use the elements of the list in preference
  50     to the real database.
  51
  52   - don't allow any locks to be held when a transaction starts,
  53     otherwise we can end up with deadlock (plus lack of lock nesting
  54     in posix locks would mean the lock is lost)
  55
  56   - if the caller gains a lock during the transaction but doesn't
  57     release it then fail the commit
  58
  59   - allow for nested calls to tdb_transaction_start(), re-using the
  60     existing transaction record. If the inner transaction is cancelled
  61     then a subsequent commit will fail
  62
  63   - keep a mirrored copy of the tdb hash chain heads to allow for the
  64     fast hash heads scan on traverse, updating the mirrored copy in
  65     the transaction version of tdb_write
  66
  67   - allow callers to mix transaction and non-transaction use of tdb,
  68     although once a transaction is started then an exclusive lock is
  69     gained until the transaction is committed or cancelled
  70
  71   - the commit stategy involves first saving away all modified data
  72     into a linearised buffer in the transaction recovery area, then
  73     marking the transaction recovery area with a magic value to
  74     indicate a valid recovery record. In total 4 fsync/msync calls are
  75     needed per commit to prevent race conditions. It might be possible
  76     to reduce this to 3 or even 2 with some more work.
  77
  78   - check for a valid recovery record on open of the tdb, while the
  79     open lock is held. Automatically recover from the transaction
  80     recovery area if needed, then continue with the open as
  81     usual. This allows for smooth crash recovery with no administrator
  82     intervention.
  83
  84   - if TDB_NOSYNC is passed to flags in tdb_open then transactions are
  85     still available, but no transaction recovery area is used and no
  86     fsync/msync calls are made.
  87
  88   - if TDB_ALLOW_NESTING is passed to flags in tdb open, or added using
  89     tdb_add_flags() transaction nesting is enabled.
  90     It resets the TDB_DISALLOW_NESTING flag, as both cannot be used together.
  91     The default is that transaction nesting is allowed.
  92     Note: this default may change in future versions of tdb.
  93
  94     Beware. when transactions are nested a transaction successfully
  95     completed with tdb_transaction_commit() can be silently unrolled later.
  96
  97   - if TDB_DISALLOW_NESTING is passed to flags in tdb open, or added using
  98     tdb_add_flags() transaction nesting is disabled.
  99     It resets the TDB_ALLOW_NESTING flag, as both cannot be used together.
 100     An attempt create a nested transaction will fail with TDB_ERR_NESTING.
 101     The default is that transaction nesting is allowed.
 102     Note: this default may change in future versions of tdb.
 103 */
 104
 105
 106 /*
 107   hold the context of any current transaction
 108 */
 109 struct tdb_transaction {
 110         /* we keep a mirrored copy of the tdb hash heads here so
 111            tdb_next_hash_chain() can operate efficiently */
 112         uint32_t *hash_heads;
 113
 114         /* the original io methods - used to do IOs to the real db */
 115         const struct tdb_methods *io_methods;
 116
 117         /* the list of transaction blocks. When a block is first
 118            written to, it gets created in this list */
 119         uint8_t **blocks;
 120         uint32_t num_blocks;
 121         uint32_t block_size;      /* bytes in each block */
 122         uint32_t last_block_size; /* number of valid bytes in the last block */
 123
 124         /* non-zero when an internal transaction error has
 125            occurred. All write operations will then fail until the
 126            transaction is ended */
 127         int transaction_error;
 128
 129         /* when inside a transaction we need to keep track of any
 130            nested tdb_transaction_start() calls, as these are allowed,
 131            but don't create a new transaction */
 132         int nesting;
 133
 134         /* set when a prepare has already occurred */
 135         bool prepared;
 136         tdb_off_t magic_offset;
 137
 138         /* old file size before transaction */
 139         tdb_len_t old_map_size;
 140
 141         /* we should re-pack on commit */
 142         bool need_repack;
 143 };
 144
 145
 146 /*
 147   read while in a transaction. We need to check first if the data is in our list
 148   of transaction elements, then if not do a real read
 149 */
 150 static int transaction_read(struct tdb_context *tdb, tdb_off_t off, void *buf,
 151                             tdb_len_t len, int cv)
 152 {
 153         uint32_t blk;
 154
 155         /* break it down into block sized ops */
 156         while (len + (off % tdb->transaction->block_size) > tdb->transaction->block_size) {
 157                 tdb_len_t len2 = tdb->transaction->block_size - (off % tdb->transaction->block_size);
 158                 if (transaction_read(tdb, off, buf, len2, cv) != 0) {
 159                         return -1;
 160                 }
 161                 len -= len2;
 162                 off += len2;
 163                 buf = (void *)(len2 + (char *)buf);
 164         }
 165
 166         if (len == 0) {
 167                 return 0;
 168         }
 169
 170         blk = off / tdb->transaction->block_size;
 171
 172         /* see if we have it in the block list */
 173         if (tdb->transaction->num_blocks <= blk ||
 174             tdb->transaction->blocks[blk] == NULL) {
 175                 /* nope, do a real read */
 176                 if (tdb->transaction->io_methods->tdb_read(tdb, off, buf, len, cv) != 0) {
 177                         goto fail;
 178                 }
 179                 return 0;
 180         }
 181
 182         /* it is in the block list. Now check for the last block */
 183         if (blk == tdb->transaction->num_blocks-1) {
 184                 if (len > tdb->transaction->last_block_size) {
 185                         goto fail;
 186                 }
 187         }
 188
 189         /* now copy it out of this block */
 190         memcpy(buf, tdb->transaction->blocks[blk] + (off % tdb->transaction->block_size), len);
 191         if (cv) {
 192                 tdb_convert(buf, len);
 193         }
 194         return 0;
 195
 196 fail:
 197         TDB_LOG((tdb, TDB_DEBUG_FATAL, "transaction_read: failed at off=%d len=%d\n", off, len));
 198         tdb->ecode = TDB_ERR_IO;
 199         tdb->transaction->transaction_error = 1;
 200         return -1;
 201 }
 202
 203
 204 /*
 205   write while in a transaction
 206 */
 207 static int transaction_write(struct tdb_context *tdb, tdb_off_t off,
 208                              const void *buf, tdb_len_t len)
 209 {
 210         uint32_t blk;
 211
 212         /* Only a commit is allowed on a prepared transaction */
 213         if (tdb->transaction->prepared) {
 214                 tdb->ecode = TDB_ERR_EINVAL;
 215                 TDB_LOG((tdb, TDB_DEBUG_FATAL, "transaction_write: transaction already prepared, write not allowed\n"));
 216                 tdb->transaction->transaction_error = 1;
 217                 return -1;
 218         }
 219
 220         /* if the write is to a hash head, then update the transaction
 221            hash heads */
 222         if (len == sizeof(tdb_off_t) && off >= FREELIST_TOP &&
 223             off < FREELIST_TOP+TDB_HASHTABLE_SIZE(tdb)) {
 224                 uint32_t chain = (off-FREELIST_TOP) / sizeof(tdb_off_t);
 225                 memcpy(&tdb->transaction->hash_heads[chain], buf, len);
 226         }
 227
 228         /* break it up into block sized chunks */
 229         while (len + (off % tdb->transaction->block_size) > tdb->transaction->block_size) {
 230                 tdb_len_t len2 = tdb->transaction->block_size - (off % tdb->transaction->block_size);
 231                 if (transaction_write(tdb, off, buf, len2) != 0) {
 232                         return -1;
 233                 }
 234                 len -= len2;
 235                 off += len2;
 236                 if (buf != NULL) {
 237                         buf = (const void *)(len2 + (const char *)buf);
 238                 }
 239         }
 240
 241         if (len == 0) {
 242                 return 0;
 243         }
 244
 245         blk = off / tdb->transaction->block_size;
 246         off = off % tdb->transaction->block_size;
 247
 248         if (tdb->transaction->num_blocks <= blk) {
 249                 uint8_t **new_blocks;
 250                 /* expand the blocks array */
 251                 if (tdb->transaction->blocks == NULL) {
 252                         new_blocks = (uint8_t **)malloc(
 253                                 (blk+1)*sizeof(uint8_t *));
 254                 } else {
 255                         new_blocks = (uint8_t **)realloc(
 256                                 tdb->transaction->blocks,
 257                                 (blk+1)*sizeof(uint8_t *));
 258                 }
 259                 if (new_blocks == NULL) {
 260                         tdb->ecode = TDB_ERR_OOM;
 261                         goto fail;
 262                 }
 263                 memset(&new_blocks[tdb->transaction->num_blocks], 0,
 264                        (1+(blk - tdb->transaction->num_blocks))*sizeof(uint8_t *));
 265                 tdb->transaction->blocks = new_blocks;
 266                 tdb->transaction->num_blocks = blk+1;
 267                 tdb->transaction->last_block_size = 0;
 268         }
 269
 270         /* allocate and fill a block? */
 271         if (tdb->transaction->blocks[blk] == NULL) {
 272                 tdb->transaction->blocks[blk] = (uint8_t *)calloc(tdb->transaction->block_size, 1);
 273                 if (tdb->transaction->blocks[blk] == NULL) {
 274                         tdb->ecode = TDB_ERR_OOM;
 275                         tdb->transaction->transaction_error = 1;
 276                         return -1;
 277                 }
 278                 if (tdb->transaction->old_map_size > blk * tdb->transaction->block_size) {
 279                         tdb_len_t len2 = tdb->transaction->block_size;
 280                         if (len2 + (blk * tdb->transaction->block_size) > tdb->transaction->old_map_size) {
 281                                 len2 = tdb->transaction->old_map_size - (blk * tdb->transaction->block_size);
 282                         }
 283                         if (tdb->transaction->io_methods->tdb_read(tdb, blk * tdb->transaction->block_size,
 284                                                                    tdb->transaction->blocks[blk],
 285                                                                    len2, 0) != 0) {
 286                                 SAFE_FREE(tdb->transaction->blocks[blk]);
 287                                 tdb->ecode = TDB_ERR_IO;
 288                                 goto fail;
 289                         }
 290                         if (blk == tdb->transaction->num_blocks-1) {
 291                                 tdb->transaction->last_block_size = len2;
 292                         }
 293                 }
 294         }
 295
 296         /* overwrite part of an existing block */
 297         if (buf == NULL) {
 298                 memset(tdb->transaction->blocks[blk] + off, 0, len);
 299         } else {
 300                 memcpy(tdb->transaction->blocks[blk] + off, buf, len);
 301         }
 302         if (blk == tdb->transaction->num_blocks-1) {
 303                 if (len + off > tdb->transaction->last_block_size) {
 304                         tdb->transaction->last_block_size = len + off;
 305                 }
 306         }
 307
 308         return 0;
 309
 310 fail:
 311         TDB_LOG((tdb, TDB_DEBUG_FATAL, "transaction_write: failed at off=%d len=%d\n",
 312                  (blk*tdb->transaction->block_size) + off, len));
 313         tdb->transaction->transaction_error = 1;
 314         return -1;
 315 }
 316
 317
 318 /*
 319   write while in a transaction - this varient never expands the transaction blocks, it only
 320   updates existing blocks. This means it cannot change the recovery size
 321 */
 322 static int transaction_write_existing(struct tdb_context *tdb, tdb_off_t off,
 323                                       const void *buf, tdb_len_t len)
 324 {
 325         uint32_t blk;
 326
 327         /* break it up into block sized chunks */
 328         while (len + (off % tdb->transaction->block_size) > tdb->transaction->block_size) {
 329                 tdb_len_t len2 = tdb->transaction->block_size - (off % tdb->transaction->block_size);
 330                 if (transaction_write_existing(tdb, off, buf, len2) != 0) {
 331                         return -1;
 332                 }
 333                 len -= len2;
 334                 off += len2;
 335                 if (buf != NULL) {
 336                         buf = (const void *)(len2 + (const char *)buf);
 337                 }
 338         }
 339
 340         if (len == 0) {
 341                 return 0;
 342         }
 343
 344         blk = off / tdb->transaction->block_size;
 345         off = off % tdb->transaction->block_size;
 346
 347         if (tdb->transaction->num_blocks <= blk ||
 348             tdb->transaction->blocks[blk] == NULL) {
 349                 return 0;
 350         }
 351
 352         if (blk == tdb->transaction->num_blocks-1 &&
 353             off + len > tdb->transaction->last_block_size) {
 354                 if (off >= tdb->transaction->last_block_size) {
 355                         return 0;
 356                 }
 357                 len = tdb->transaction->last_block_size - off;
 358         }
 359
 360         /* overwrite part of an existing block */
 361         memcpy(tdb->transaction->blocks[blk] + off, buf, len);
 362
 363         return 0;
 364 }
 365
 366
 367 /*
 368   accelerated hash chain head search, using the cached hash heads
 369 */
 370 static void transaction_next_hash_chain(struct tdb_context *tdb, uint32_t *chain)
 371 {
 372         uint32_t h = *chain;
 373         for (;h < tdb->header.hash_size;h++) {
 374                 /* the +1 takes account of the freelist */
 375                 if (0 != tdb->transaction->hash_heads[h+1]) {
 376                         break;
 377                 }
 378         }
 379         (*chain) = h;
 380 }
 381
 382 /*
 383   out of bounds check during a transaction
 384 */
 385 static int transaction_oob(struct tdb_context *tdb, tdb_off_t len, int probe)
 386 {
 387         if (len <= tdb->map_size) {
 388                 return 0;
 389         }
 390         tdb->ecode = TDB_ERR_IO;
 391         return -1;
 392 }
 393
 394 /*
 395   transaction version of tdb_expand().
 396 */
 397 static int transaction_expand_file(struct tdb_context *tdb, tdb_off_t size,
 398                                    tdb_off_t addition)
 399 {
 400         /* add a write to the transaction elements, so subsequent
 401            reads see the zero data */
 402         if (transaction_write(tdb, size, NULL, addition) != 0) {
 403                 return -1;
 404         }
 405
 406         tdb->transaction->need_repack = true;
 407
 408         return 0;
 409 }
 410
 411 /*
 412   brlock during a transaction - ignore them
 413 */
 414 static int transaction_brlock(struct tdb_context *tdb,
 415                               int rw_type, tdb_off_t offset, size_t len,
 416                               enum tdb_lock_flags flags)
 417 {
 418         /* FIXME: We actually grab the open lock during a transaction. */
 419         if (offset == OPEN_LOCK)
 420                 return tdb_brlock(tdb, rw_type, offset, len, flags);
 421         return 0;
 422 }
 423
 424 static int transaction_brunlock(struct tdb_context *tdb,
 425                                 int rw_type, tdb_off_t offset, size_t len)
 426 {
 427         return 0;
 428 }
 429
 430 static const struct tdb_methods transaction_methods = {
 431         transaction_read,
 432         transaction_write,
 433         transaction_next_hash_chain,
 434         transaction_oob,
 435         transaction_expand_file,
 436         transaction_brlock,
 437         transaction_brunlock
 438 };
 439
 440
 441 /*
 442   start a tdb transaction. No token is returned, as only a single
 443   transaction is allowed to be pending per tdb_context
 444 */
 445 int tdb_transaction_start(struct tdb_context *tdb)
 446 {
 447         /* some sanity checks */
 448         if (tdb->read_only || (tdb->flags & TDB_INTERNAL) || tdb->traverse_read) {
 449                 TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_transaction_start: cannot start a transaction on a read-only or internal db\n"));
 450                 tdb->ecode = TDB_ERR_EINVAL;
 451                 return -1;
 452         }
 453
 454         /* cope with nested tdb_transaction_start() calls */
 455         if (tdb->transaction != NULL) {
 456                 if (!(tdb->flags & TDB_ALLOW_NESTING)) {
 457                         tdb->ecode = TDB_ERR_NESTING;
 458                         return -1;
 459                 }
 460                 tdb->transaction->nesting++;
 461                 TDB_LOG((tdb, TDB_DEBUG_TRACE, "tdb_transaction_start: nesting %d\n",
 462                          tdb->transaction->nesting));
 463                 return 0;
 464         }
 465
 466         if (tdb_have_extra_locks(tdb)) {
 467                 /* the caller must not have any locks when starting a
 468                    transaction as otherwise we'll be screwed by lack
 469                    of nested locks in posix */
 470                 TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_transaction_start: cannot start a transaction with locks held\n"));
 471                 tdb->ecode = TDB_ERR_LOCK;
 472                 return -1;
 473         }
 474
 475         if (tdb->travlocks.next != NULL) {
 476                 /* you cannot use transactions inside a traverse (although you can use
 477                    traverse inside a transaction) as otherwise you can end up with
 478                    deadlock */
 479                 TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_transaction_start: cannot start a transaction within a traverse\n"));
 480                 tdb->ecode = TDB_ERR_LOCK;
 481                 return -1;
 482         }
 483
 484         tdb->transaction = (struct tdb_transaction *)
 485                 calloc(sizeof(struct tdb_transaction), 1);
 486         if (tdb->transaction == NULL) {
 487                 tdb->ecode = TDB_ERR_OOM;
 488                 return -1;
 489         }
 490
 491         /* a page at a time seems like a reasonable compromise between compactness and efficiency */
 492         tdb->transaction->block_size = tdb->page_size;
 493
 494         /* get the transaction write lock. This is a blocking lock. As
 495            discussed with Volker, there are a number of ways we could
 496            make this async, which we will probably do in the future */
 497         if (tdb_transaction_lock(tdb, F_WRLCK) == -1) {
 498                 SAFE_FREE(tdb->transaction->blocks);
 499                 SAFE_FREE(tdb->transaction);
 500                 return -1;
 501         }
 502
 503         /* get a read lock from the freelist to the end of file. This
 504            is upgraded to a write lock during the commit */
 505         if (tdb_allrecord_lock(tdb, F_RDLCK, TDB_LOCK_WAIT, true) == -1) {
 506                 TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_transaction_start: failed to get hash locks\n"));
 507                 goto fail_allrecord_lock;
 508         }
 509
 510         /* setup a copy of the hash table heads so the hash scan in
 511            traverse can be fast */
 512         tdb->transaction->hash_heads = (uint32_t *)
 513                 calloc(tdb->header.hash_size+1, sizeof(uint32_t));
 514         if (tdb->transaction->hash_heads == NULL) {
 515                 tdb->ecode = TDB_ERR_OOM;
 516                 goto fail;
 517         }
 518         if (tdb->methods->tdb_read(tdb, FREELIST_TOP, tdb->transaction->hash_heads,
 519                                    TDB_HASHTABLE_SIZE(tdb), 0) != 0) {
 520                 TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_transaction_start: failed to read hash heads\n"));
 521                 tdb->ecode = TDB_ERR_IO;
 522                 goto fail;
 523         }
 524
 525         /* make sure we know about any file expansions already done by
 526            anyone else */
 527         tdb->methods->tdb_oob(tdb, tdb->map_size + 1, 1);
 528         tdb->transaction->old_map_size = tdb->map_size;
 529
 530         /* finally hook the io methods, replacing them with
 531            transaction specific methods */
 532         tdb->transaction->io_methods = tdb->methods;
 533         tdb->methods = &transaction_methods;
 534
 535         /* Trace at the end, so we get sequence number correct. */
 536         tdb_trace(tdb, "tdb_transaction_start");
 537         return 0;
 538
 539 fail:
 540         tdb_allrecord_unlock(tdb, F_RDLCK, false);
 541 fail_allrecord_lock:
 542         tdb_transaction_unlock(tdb, F_WRLCK);
 543         SAFE_FREE(tdb->transaction->blocks);
 544         SAFE_FREE(tdb->transaction->hash_heads);
 545         SAFE_FREE(tdb->transaction);
 546         return -1;
 547 }
 548
 549
 550 /*
 551   sync to disk
 552 */
 553 static int transaction_sync(struct tdb_context *tdb, tdb_off_t offset, tdb_len_t length)
 554 {
 555         if (tdb->flags & TDB_NOSYNC) {
 556                 return 0;
 557         }
 558
 559         if (fdatasync(tdb->fd) != 0) {
 560                 tdb->ecode = TDB_ERR_IO;
 561                 TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_transaction: fsync failed\n"));
 562                 return -1;
 563         }
 564 #ifdef HAVE_MMAP
 565         if (tdb->map_ptr) {
 566                 tdb_off_t moffset = offset & ~(tdb->page_size-1);
 567                 if (msync(moffset + (char *)tdb->map_ptr,
 568                           length + (offset - moffset), MS_SYNC) != 0) {
 569                         tdb->ecode = TDB_ERR_IO;
 570                         TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_transaction: msync failed - %s\n",
 571                                  strerror(errno)));
 572                         return -1;
 573                 }
 574         }
 575 #endif
 576         return 0;
 577 }
 578
 579
 580 /* ltype is F_WRLCK after prepare. */
 581 static int _tdb_transaction_cancel(struct tdb_context *tdb, int ltype)
 582 {
 583         int i, ret = 0;
 584
 585         if (tdb->transaction == NULL) {
 586                 TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_transaction_cancel: no transaction\n"));
 587                 return -1;
 588         }
 589
 590         if (tdb->transaction->nesting != 0) {
 591                 tdb->transaction->transaction_error = 1;
 592                 tdb->transaction->nesting--;
 593                 return 0;
 594         }
 595
 596         tdb->map_size = tdb->transaction->old_map_size;
 597
 598         /* free all the transaction blocks */
 599         for (i=0;i<tdb->transaction->num_blocks;i++) {
 600                 if (tdb->transaction->blocks[i] != NULL) {
 601                         free(tdb->transaction->blocks[i]);
 602                 }
 603         }
 604         SAFE_FREE(tdb->transaction->blocks);
 605
 606         if (tdb->transaction->magic_offset) {
 607                 const struct tdb_methods *methods = tdb->transaction->io_methods;
 608                 const uint32_t invalid = TDB_RECOVERY_INVALID_MAGIC;
 609
 610                 /* remove the recovery marker */
 611                 if (methods->tdb_write(tdb, tdb->transaction->magic_offset, &invalid, 4) == -1 ||
 612                 transaction_sync(tdb, tdb->transaction->magic_offset, 4) == -1) {
 613                         TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_transaction_cancel: failed to remove recovery magic\n"));
 614                         ret = -1;
 615                 }
 616         }
 617
 618         /* This also removes the OPEN_LOCK, if we have it. */
 619         tdb_release_extra_locks(tdb);
 620
 621         /* restore the normal io methods */
 622         tdb->methods = tdb->transaction->io_methods;
 623
 624         tdb_transaction_unlock(tdb, F_WRLCK);
 625         SAFE_FREE(tdb->transaction->hash_heads);
 626         SAFE_FREE(tdb->transaction);
 627
 628         return ret;
 629 }
 630
 631 /*
 632   cancel the current transaction
 633 */
 634 int tdb_transaction_cancel(struct tdb_context *tdb)
 635 {
 636         int ltype = F_RDLCK;
 637         tdb_trace(tdb, "tdb_transaction_cancel");
 638         if (tdb->transaction && tdb->transaction->prepared)
 639                 ltype = F_WRLCK;
 640         return _tdb_transaction_cancel(tdb, ltype);
 641 }
 642
 643 /*
 644   work out how much space the linearised recovery data will consume
 645 */
 646 static tdb_len_t tdb_recovery_size(struct tdb_context *tdb)
 647 {
 648         tdb_len_t recovery_size = 0;
 649         int i;
 650
 651         recovery_size = sizeof(uint32_t);
 652         for (i=0;i<tdb->transaction->num_blocks;i++) {
 653                 if (i * tdb->transaction->block_size >= tdb->transaction->old_map_size) {
 654                         break;
 655                 }
 656                 if (tdb->transaction->blocks[i] == NULL) {
 657                         continue;
 658                 }
 659                 recovery_size += 2*sizeof(tdb_off_t);
 660                 if (i == tdb->transaction->num_blocks-1) {
 661                         recovery_size += tdb->transaction->last_block_size;
 662                 } else {
 663                         recovery_size += tdb->transaction->block_size;
 664                 }
 665         }
 666
 667         return recovery_size;
 668 }
 669
 670 /*
 671   allocate the recovery area, or use an existing recovery area if it is
 672   large enough
 673 */
 674 static int tdb_recovery_allocate(struct tdb_context *tdb,
 675                                  tdb_len_t *recovery_size,
 676                                  tdb_off_t *recovery_offset,
 677                                  tdb_len_t *recovery_max_size)
 678 {
 679         struct tdb_record rec;
 680         const struct tdb_methods *methods = tdb->transaction->io_methods;
 681         tdb_off_t recovery_head;
 682
 683         if (tdb_ofs_read(tdb, TDB_RECOVERY_HEAD, &recovery_head) == -1) {
 684                 TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_recovery_allocate: failed to read recovery head\n"));
 685                 return -1;
 686         }
 687
 688         rec.rec_len = 0;
 689
 690         if (recovery_head != 0) {
 691                 if (methods->tdb_read(tdb, recovery_head, &rec, sizeof(rec), DOCONV()) == -1) {
 692                         TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_recovery_allocate: failed to read recovery record\n"));
 693                         return -1;
 694                 }
 695                 /* ignore invalid recovery regions: can happen in crash */
 696                 if (rec.magic != TDB_RECOVERY_MAGIC &&
 697                     rec.magic != TDB_RECOVERY_INVALID_MAGIC) {
 698                         recovery_head = 0;
 699                 }
 700         }
 701
 702         *recovery_size = tdb_recovery_size(tdb);
 703
 704         if (recovery_head != 0 && *recovery_size <= rec.rec_len) {
 705                 /* it fits in the existing area */
 706                 *recovery_max_size = rec.rec_len;
 707                 *recovery_offset = recovery_head;
 708                 return 0;
 709         }
 710
 711         /* we need to free up the old recovery area, then allocate a
 712            new one at the end of the file. Note that we cannot use
 713            tdb_allocate() to allocate the new one as that might return
 714            us an area that is being currently used (as of the start of
 715            the transaction) */
 716         if (recovery_head != 0) {
 717                 if (tdb_free(tdb, recovery_head, &rec) == -1) {
 718                         TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_recovery_allocate: failed to free previous recovery area\n"));
 719                         return -1;
 720                 }
 721         }
 722
 723         /* the tdb_free() call might have increased the recovery size */
 724         *recovery_size = tdb_recovery_size(tdb);
 725
 726         /* round up to a multiple of page size */
 727         *recovery_max_size = TDB_ALIGN(sizeof(rec) + *recovery_size, tdb->page_size) - sizeof(rec);
 728         *recovery_offset = tdb->map_size;
 729         recovery_head = *recovery_offset;
 730
 731         if (methods->tdb_expand_file(tdb, tdb->transaction->old_map_size,
 732                                      (tdb->map_size - tdb->transaction->old_map_size) +
 733                                      sizeof(rec) + *recovery_max_size) == -1) {
 734                 TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_recovery_allocate: failed to create recovery area\n"));
 735                 return -1;
 736         }
 737
 738         /* remap the file (if using mmap) */
 739         methods->tdb_oob(tdb, tdb->map_size + 1, 1);
 740
 741         /* we have to reset the old map size so that we don't try to expand the file
 742            again in the transaction commit, which would destroy the recovery area */
 743         tdb->transaction->old_map_size = tdb->map_size;
 744
 745         /* write the recovery header offset and sync - we can sync without a race here
 746            as the magic ptr in the recovery record has not been set */
 747         CONVERT(recovery_head);
 748         if (methods->tdb_write(tdb, TDB_RECOVERY_HEAD,
 749                                &recovery_head, sizeof(tdb_off_t)) == -1) {
 750                 TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_recovery_allocate: failed to write recovery head\n"));
 751                 return -1;
 752         }
 753         if (transaction_write_existing(tdb, TDB_RECOVERY_HEAD, &recovery_head, sizeof(tdb_off_t)) == -1) {
 754                 TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_recovery_allocate: failed to write recovery head\n"));
 755                 return -1;
 756         }
 757
 758         return 0;
 759 }
 760
 761
 762 /*
 763   setup the recovery data that will be used on a crash during commit
 764 */
 765 static int transaction_setup_recovery(struct tdb_context *tdb,
 766                                       tdb_off_t *magic_offset)
 767 {
 768         tdb_len_t recovery_size;
 769         unsigned char *data, *p;
 770         const struct tdb_methods *methods = tdb->transaction->io_methods;
 771         struct tdb_record *rec;
 772         tdb_off_t recovery_offset, recovery_max_size;
 773         tdb_off_t old_map_size = tdb->transaction->old_map_size;
 774         uint32_t magic, tailer;
 775         int i;
 776
 777         /*
 778           check that the recovery area has enough space
 779         */
 780         if (tdb_recovery_allocate(tdb, &recovery_size,
 781                                   &recovery_offset, &recovery_max_size) == -1) {
 782                 return -1;
 783         }
 784
 785         data = (unsigned char *)malloc(recovery_size + sizeof(*rec));
 786         if (data == NULL) {
 787                 tdb->ecode = TDB_ERR_OOM;
 788                 return -1;
 789         }
 790
 791         rec = (struct tdb_record *)data;
 792         memset(rec, 0, sizeof(*rec));
 793
 794         rec->magic    = TDB_RECOVERY_INVALID_MAGIC;
 795         rec->data_len = recovery_size;
 796         rec->rec_len  = recovery_max_size;
 797         rec->key_len  = old_map_size;
 798         CONVERT(rec);
 799
 800         /* build the recovery data into a single blob to allow us to do a single
 801            large write, which should be more efficient */
 802         p = data + sizeof(*rec);
 803         for (i=0;i<tdb->transaction->num_blocks;i++) {
 804                 tdb_off_t offset;
 805                 tdb_len_t length;
 806
 807                 if (tdb->transaction->blocks[i] == NULL) {
 808                         continue;
 809                 }
 810
 811                 offset = i * tdb->transaction->block_size;
 812                 length = tdb->transaction->block_size;
 813                 if (i == tdb->transaction->num_blocks-1) {
 814                         length = tdb->transaction->last_block_size;
 815                 }
 816
 817                 if (offset >= old_map_size) {
 818                         continue;
 819                 }
 820                 if (offset + length > tdb->transaction->old_map_size) {
 821                         TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_transaction_setup_recovery: transaction data over new region boundary\n"));
 822                         free(data);
 823                         tdb->ecode = TDB_ERR_CORRUPT;
 824                         return -1;
 825                 }
 826                 memcpy(p, &offset, 4);
 827                 memcpy(p+4, &length, 4);
 828                 if (DOCONV()) {
 829                         tdb_convert(p, 8);
 830                 }
 831                 /* the recovery area contains the old data, not the
 832                    new data, so we have to call the original tdb_read
 833                    method to get it */
 834                 if (methods->tdb_read(tdb, offset, p + 8, length, 0) != 0) {
 835                         free(data);
 836                         tdb->ecode = TDB_ERR_IO;
 837                         return -1;
 838                 }
 839                 p += 8 + length;
 840         }
 841
 842         /* and the tailer */
 843         tailer = sizeof(*rec) + recovery_max_size;
 844         memcpy(p, &tailer, 4);
 845         CONVERT(p);
 846
 847         /* write the recovery data to the recovery area */
 848         if (methods->tdb_write(tdb, recovery_offset, data, sizeof(*rec) + recovery_size) == -1) {
 849                 TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_transaction_setup_recovery: failed to write recovery data\n"));
 850                 free(data);
 851                 tdb->ecode = TDB_ERR_IO;
 852                 return -1;
 853         }
 854         if (transaction_write_existing(tdb, recovery_offset, data, sizeof(*rec) + recovery_size) == -1) {
 855                 TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_transaction_setup_recovery: failed to write secondary recovery data\n"));
 856                 free(data);
 857                 tdb->ecode = TDB_ERR_IO;
 858                 return -1;
 859         }
 860
 861         /* as we don't have ordered writes, we have to sync the recovery
 862            data before we update the magic to indicate that the recovery
 863            data is present */
 864         if (transaction_sync(tdb, recovery_offset, sizeof(*rec) + recovery_size) == -1) {
 865                 free(data);
 866                 return -1;
 867         }
 868
 869         free(data);
 870
 871         magic = TDB_RECOVERY_MAGIC;
 872         CONVERT(magic);
 873
 874         *magic_offset = recovery_offset + offsetof(struct tdb_record, magic);
 875
 876         if (methods->tdb_write(tdb, *magic_offset, &magic, sizeof(magic)) == -1) {
 877                 TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_transaction_setup_recovery: failed to write recovery magic\n"));
 878                 tdb->ecode = TDB_ERR_IO;
 879                 return -1;
 880         }
 881         if (transaction_write_existing(tdb, *magic_offset, &magic, sizeof(magic)) == -1) {
 882                 TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_transaction_setup_recovery: failed to write secondary recovery magic\n"));
 883                 tdb->ecode = TDB_ERR_IO;
 884                 return -1;
 885         }
 886
 887         /* ensure the recovery magic marker is on disk */
 888         if (transaction_sync(tdb, *magic_offset, sizeof(magic)) == -1) {
 889                 return -1;
 890         }
 891
 892         return 0;
 893 }
 894
 895 static int _tdb_transaction_prepare_commit(struct tdb_context *tdb)
 896 {
 897         const struct tdb_methods *methods;
 898
 899         if (tdb->transaction == NULL) {
 900                 TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_transaction_prepare_commit: no transaction\n"));
 901                 return -1;
 902         }
 903
 904         if (tdb->transaction->prepared) {
 905                 tdb->ecode = TDB_ERR_EINVAL;
 906                 _tdb_transaction_cancel(tdb, F_WRLCK);
 907                 TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_transaction_prepare_commit: transaction already prepared\n"));
 908                 return -1;
 909         }
 910
 911         if (tdb->transaction->transaction_error) {
 912                 tdb->ecode = TDB_ERR_IO;
 913                 _tdb_transaction_cancel(tdb, F_RDLCK);
 914                 TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_transaction_prepare_commit: transaction error pending\n"));
 915                 return -1;
 916         }
 917
 918
 919         if (tdb->transaction->nesting != 0) {
 920                 return 0;
 921         }
 922
 923         /* check for a null transaction */
 924         if (tdb->transaction->blocks == NULL) {
 925                 return 0;
 926         }
 927
 928         methods = tdb->transaction->io_methods;
 929
 930         /* if there are any locks pending then the caller has not
 931            nested their locks properly, so fail the transaction */
 932         if (tdb_have_extra_locks(tdb)) {
 933                 tdb->ecode = TDB_ERR_LOCK;
 934                 TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_transaction_prepare_commit: locks pending on commit\n"));
 935                 _tdb_transaction_cancel(tdb, F_RDLCK);
 936                 return -1;
 937         }
 938
 939         /* upgrade the main transaction lock region to a write lock */
 940         if (tdb_allrecord_upgrade(tdb) == -1) {
 941                 TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_transaction_prepare_commit: failed to upgrade hash locks\n"));
 942                 _tdb_transaction_cancel(tdb, F_RDLCK);
 943                 return -1;
 944         }
 945
 946         /* get the open lock - this prevents new users attaching to the database
 947            during the commit */
 948         if (tdb_nest_lock(tdb, OPEN_LOCK, F_WRLCK, TDB_LOCK_WAIT) == -1) {
 949                 TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_transaction_prepare_commit: failed to get open lock\n"));
 950                 _tdb_transaction_cancel(tdb, F_WRLCK);
 951                 return -1;
 952         }
 953
 954         if (!(tdb->flags & TDB_NOSYNC)) {
 955                 /* write the recovery data to the end of the file */
 956                 if (transaction_setup_recovery(tdb, &tdb->transaction->magic_offset) == -1) {
 957                         TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_transaction_prepare_commit: failed to setup recovery data\n"));
 958                         _tdb_transaction_cancel(tdb, F_WRLCK);
 959                         return -1;
 960                 }
 961         }
 962
 963         tdb->transaction->prepared = true;
 964
 965         /* expand the file to the new size if needed */
 966         if (tdb->map_size != tdb->transaction->old_map_size) {
 967                 if (methods->tdb_expand_file(tdb, tdb->transaction->old_map_size,
 968                                              tdb->map_size -
 969                                              tdb->transaction->old_map_size) == -1) {
 970                         tdb->ecode = TDB_ERR_IO;
 971                         TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_transaction_prepare_commit: expansion failed\n"));
 972                         _tdb_transaction_cancel(tdb, F_WRLCK);
 973                         return -1;
 974                 }
 975                 tdb->map_size = tdb->transaction->old_map_size;
 976                 methods->tdb_oob(tdb, tdb->map_size + 1, 1);
 977         }
 978
 979         /* Keep the open lock until the actual commit */
 980
 981         return 0;
 982 }
 983
 984 /*
 985    prepare to commit the current transaction
 986 */
 987 int tdb_transaction_prepare_commit(struct tdb_context *tdb)
 988 {
 989         tdb_trace(tdb, "tdb_transaction_prepare_commit");
 990         return _tdb_transaction_prepare_commit(tdb);
 991 }
 992
 993 /*
 994   commit the current transaction
 995 */
 996 int tdb_transaction_commit(struct tdb_context *tdb)
 997 {
 998         const struct tdb_methods *methods;
 999         int i;
1000         bool need_repack;
1001
1002         if (tdb->transaction == NULL) {
1003                 TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_transaction_commit: no transaction\n"));
1004                 return -1;
1005         }
1006
1007         tdb_trace(tdb, "tdb_transaction_commit");
1008
1009         if (tdb->transaction->transaction_error) {
1010                 tdb->ecode = TDB_ERR_IO;
1011                 _tdb_transaction_cancel(tdb, F_RDLCK);
1012                 TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_transaction_commit: transaction error pending\n"));
1013                 return -1;
1014         }
1015
1016
1017         if (tdb->transaction->nesting != 0) {
1018                 tdb->transaction->nesting--;
1019                 return 0;
1020         }
1021
1022         /* check for a null transaction */
1023         if (tdb->transaction->blocks == NULL) {
1024                 _tdb_transaction_cancel(tdb, F_RDLCK);
1025                 return 0;
1026         }
1027
1028         if (!tdb->transaction->prepared) {
1029                 int ret = _tdb_transaction_prepare_commit(tdb);
1030                 if (ret)
1031                         return ret;
1032         }
1033
1034         methods = tdb->transaction->io_methods;
1035
1036         /* perform all the writes */
1037         for (i=0;i<tdb->transaction->num_blocks;i++) {
1038                 tdb_off_t offset;
1039                 tdb_len_t length;
1040
1041                 if (tdb->transaction->blocks[i] == NULL) {
1042                         continue;
1043                 }
1044
1045                 offset = i * tdb->transaction->block_size;
1046                 length = tdb->transaction->block_size;
1047                 if (i == tdb->transaction->num_blocks-1) {
1048                         length = tdb->transaction->last_block_size;
1049                 }
1050
1051                 if (methods->tdb_write(tdb, offset, tdb->transaction->blocks[i], length) == -1) {
1052                         TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_transaction_commit: write failed during commit\n"));
1053
1054                         /* we've overwritten part of the data and
1055                            possibly expanded the file, so we need to
1056                            run the crash recovery code */
1057                         tdb->methods = methods;
1058                         tdb_transaction_recover(tdb);
1059
1060                         _tdb_transaction_cancel(tdb, F_WRLCK);
1061
1062                         TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_transaction_commit: write failed\n"));
1063                         return -1;
1064                 }
1065                 SAFE_FREE(tdb->transaction->blocks[i]);
1066         }
1067
1068         SAFE_FREE(tdb->transaction->blocks);
1069         tdb->transaction->num_blocks = 0;
1070
1071         /* ensure the new data is on disk */
1072         if (transaction_sync(tdb, 0, tdb->map_size) == -1) {
1073                 return -1;
1074         }
1075
1076         /*
1077           TODO: maybe write to some dummy hdr field, or write to magic
1078           offset without mmap, before the last sync, instead of the
1079           utime() call
1080         */
1081
1082         /* on some systems (like Linux 2.6.x) changes via mmap/msync
1083            don't change the mtime of the file, this means the file may
1084            not be backed up (as tdb rounding to block sizes means that
1085            file size changes are quite rare too). The following forces
1086            mtime changes when a transaction completes */
1087 #ifdef HAVE_UTIME
1088         utime(tdb->name, NULL);
1089 #endif
1090
1091         need_repack = tdb->transaction->need_repack;
1092
1093         /* use a transaction cancel to free memory and remove the
1094            transaction locks */
1095         _tdb_transaction_cancel(tdb, F_WRLCK);
1096
1097         if (need_repack) {
1098                 return tdb_repack(tdb);
1099         }
1100
1101         return 0;
1102 }
1103
1104
1105 /*
1106   recover from an aborted transaction. Must be called with exclusive
1107   database write access already established (including the open
1108   lock to prevent new processes attaching)
1109 */
1110 int tdb_transaction_recover(struct tdb_context *tdb)
1111 {
1112         tdb_off_t recovery_head, recovery_eof;
1113         unsigned char *data, *p;
1114         uint32_t zero = 0;
1115         struct tdb_record rec;
1116
1117         /* find the recovery area */
1118         if (tdb_ofs_read(tdb, TDB_RECOVERY_HEAD, &recovery_head) == -1) {
1119                 TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_transaction_recover: failed to read recovery head\n"));
1120                 tdb->ecode = TDB_ERR_IO;
1121                 return -1;
1122         }
1123
1124         if (recovery_head == 0) {
1125                 /* we have never allocated a recovery record */
1126                 return 0;
1127         }
1128
1129         /* read the recovery record */
1130         if (tdb->methods->tdb_read(tdb, recovery_head, &rec,
1131                                    sizeof(rec), DOCONV()) == -1) {
1132                 TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_transaction_recover: failed to read recovery record\n"));
1133                 tdb->ecode = TDB_ERR_IO;
1134                 return -1;
1135         }
1136
1137         if (rec.magic != TDB_RECOVERY_MAGIC) {
1138                 /* there is no valid recovery data */
1139                 return 0;
1140         }
1141
1142         if (tdb->read_only) {
1143                 TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_transaction_recover: attempt to recover read only database\n"));
1144                 tdb->ecode = TDB_ERR_CORRUPT;
1145                 return -1;
1146         }
1147
1148         recovery_eof = rec.key_len;
1149
1150         data = (unsigned char *)malloc(rec.data_len);
1151         if (data == NULL) {
1152                 TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_transaction_recover: failed to allocate recovery data\n"));
1153                 tdb->ecode = TDB_ERR_OOM;
1154                 return -1;
1155         }
1156
1157         /* read the full recovery data */
1158         if (tdb->methods->tdb_read(tdb, recovery_head + sizeof(rec), data,
1159                                    rec.data_len, 0) == -1) {
1160                 TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_transaction_recover: failed to read recovery data\n"));
1161                 tdb->ecode = TDB_ERR_IO;
1162                 return -1;
1163         }
1164
1165         /* recover the file data */
1166         p = data;
1167         while (p+8 < data + rec.data_len) {
1168                 uint32_t ofs, len;
1169                 if (DOCONV()) {
1170                         tdb_convert(p, 8);
1171                 }
1172                 memcpy(&ofs, p, 4);
1173                 memcpy(&len, p+4, 4);
1174
1175                 if (tdb->methods->tdb_write(tdb, ofs, p+8, len) == -1) {
1176                         free(data);
1177                         TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_transaction_recover: failed to recover %d bytes at offset %d\n", len, ofs));
1178                         tdb->ecode = TDB_ERR_IO;
1179                         return -1;
1180                 }
1181                 p += 8 + len;
1182         }
1183
1184         free(data);
1185
1186         if (transaction_sync(tdb, 0, tdb->map_size) == -1) {
1187                 TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_transaction_recover: failed to sync recovery\n"));
1188                 tdb->ecode = TDB_ERR_IO;
1189                 return -1;
1190         }
1191
1192         /* if the recovery area is after the recovered eof then remove it */
1193         if (recovery_eof <= recovery_head) {
1194                 if (tdb_ofs_write(tdb, TDB_RECOVERY_HEAD, &zero) == -1) {
1195                         TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_transaction_recover: failed to remove recovery head\n"));
1196                         tdb->ecode = TDB_ERR_IO;
1197                         return -1;
1198                 }
1199         }
1200
1201         /* remove the recovery magic */
1202         if (tdb_ofs_write(tdb, recovery_head + offsetof(struct tdb_record, magic),
1203                           &zero) == -1) {
1204                 TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_transaction_recover: failed to remove recovery magic\n"));
1205                 tdb->ecode = TDB_ERR_IO;
1206                 return -1;
1207         }
1208
1209         /* reduce the file size to the old size */
1210         tdb_munmap(tdb);
1211         if (ftruncate(tdb->fd, recovery_eof) != 0) {
1212                 TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_transaction_recover: failed to reduce to recovery size\n"));
1213                 tdb->ecode = TDB_ERR_IO;
1214                 return -1;
1215         }
1216         tdb->map_size = recovery_eof;
1217         tdb_mmap(tdb);
1218
1219         if (transaction_sync(tdb, 0, recovery_eof) == -1) {
1220                 TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_transaction_recover: failed to sync2 recovery\n"));
1221                 tdb->ecode = TDB_ERR_IO;
1222                 return -1;
1223         }
1224
1225         TDB_LOG((tdb, TDB_DEBUG_TRACE, "tdb_transaction_recover: recovered %d byte database\n",
1226                  recovery_eof));
1227
1228         /* all done */
1229         return 0;
1230 }