2 Unix SMB/CIFS implementation.
4 trivial database library
6 Copyright (C) Andrew Tridgell 1999-2005
7 Copyright (C) Paul `Rusty' Russell 2000
8 Copyright (C) Jeremy Allison 2000-2003
10 ** NOTE! The following LGPL license applies to the tdb
11 ** library. This does NOT imply that all of Samba is released
14 This library is free software; you can redistribute it and/or
15 modify it under the terms of the GNU Lesser General Public
16 License as published by the Free Software Foundation; either
17 version 3 of the License, or (at your option) any later version.
19 This library is distributed in the hope that it will be useful,
20 but WITHOUT ANY WARRANTY; without even the implied warranty of
21 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
22 Lesser General Public License for more details.
24 You should have received a copy of the GNU Lesser General Public
25 License along with this library; if not, see <http://www.gnu.org/licenses/>.
30 #include <ccan/build_assert/build_assert.h>
32 static int fcntl_lock(struct tdb_context *tdb,
33 int rw, off_t off, off_t len, bool waitflag)
38 fl.l_whence = SEEK_SET;
44 return fcntl(tdb->fd, F_SETLKW, &fl);
46 return fcntl(tdb->fd, F_SETLK, &fl);
49 static int fcntl_unlock(struct tdb_context *tdb, int rw, off_t off, off_t len)
52 #if 0 /* Check they matched up locks and unlocks correctly. */
57 locks = fopen("/proc/locks", "r");
59 while (fgets(line, 80, locks)) {
63 /* eg. 1: FLOCK ADVISORY WRITE 2440 08:01:2180826 0 EOF */
64 p = strchr(line, ':') + 1;
65 if (strncmp(p, " POSIX ADVISORY ", strlen(" POSIX ADVISORY ")))
67 p += strlen(" FLOCK ADVISORY ");
68 if (strncmp(p, "READ ", strlen("READ ")) == 0)
70 else if (strncmp(p, "WRITE ", strlen("WRITE ")) == 0)
75 if (atoi(p) != getpid())
77 p = strchr(strchr(p, ' ') + 1, ' ') + 1;
79 p = strchr(p, ' ') + 1;
80 if (strncmp(p, "EOF", 3) == 0)
83 l = atoi(p) - start + 1;
87 fprintf(stderr, "Len %u should be %u: %s",
92 fprintf(stderr, "Type %s wrong: %s",
93 rw == F_RDLCK ? "READ" : "WRITE", line);
102 fprintf(stderr, "Unlock on %u@%u not found!\n",
111 fl.l_whence = SEEK_SET;
116 return fcntl(tdb->fd, F_SETLKW, &fl);
119 /* a byte range locking function - return 0 on success
120 this functions locks/unlocks 1 byte at the specified offset.
122 note that a len of zero means lock to end of file
124 static int tdb_brlock(struct tdb_context *tdb,
125 int rw_type, tdb_off_t offset, tdb_off_t len,
126 enum tdb_lock_flags flags)
130 if (tdb->flags & TDB_NOLOCK) {
134 if (rw_type == F_WRLCK && tdb->read_only) {
135 tdb->ecode = TDB_ERR_RDONLY;
139 /* A 32 bit system cannot open a 64-bit file, but it could have
140 * expanded since then: check here. */
141 if ((size_t)(offset + len) != offset + len) {
142 tdb->ecode = TDB_ERR_IO;
143 tdb->log(tdb, TDB_DEBUG_ERROR, tdb->log_priv,
144 "tdb_brlock: lock on giant offset %llu\n",
145 (long long)(offset + len));
150 ret = fcntl_lock(tdb, rw_type, offset, len,
151 flags & TDB_LOCK_WAIT);
152 } while (ret == -1 && errno == EINTR);
155 tdb->ecode = TDB_ERR_LOCK;
156 /* Generic lock error. errno set by fcntl.
157 * EAGAIN is an expected return from non-blocking
159 if (!(flags & TDB_LOCK_PROBE) && errno != EAGAIN) {
160 tdb->log(tdb, TDB_DEBUG_ERROR, tdb->log_priv,
161 "tdb_brlock failed (fd=%d) at"
162 " offset %llu rw_type=%d flags=%d len=%llu\n",
163 tdb->fd, (long long)offset, rw_type,
164 flags, (long long)len);
171 static int tdb_brunlock(struct tdb_context *tdb,
172 int rw_type, tdb_off_t offset, size_t len)
176 if (tdb->flags & TDB_NOLOCK) {
181 ret = fcntl_unlock(tdb, rw_type, offset, len);
182 } while (ret == -1 && errno == EINTR);
185 tdb->log(tdb, TDB_DEBUG_TRACE, tdb->log_priv,
186 "tdb_brunlock failed (fd=%d) at offset %llu"
187 " rw_type=%d len=%llu\n",
188 tdb->fd, (long long)offset, rw_type, (long long)len);
195 upgrade a read lock to a write lock. This needs to be handled in a
196 special way as some OSes (such as solaris) have too conservative
197 deadlock detection and claim a deadlock when progress can be
198 made. For those OSes we may loop for a while.
200 int tdb_allrecord_upgrade(struct tdb_context *tdb)
204 if (tdb->allrecord_lock.count != 1) {
205 tdb->log(tdb, TDB_DEBUG_ERROR, tdb->log_priv,
206 "tdb_allrecord_upgrade failed: count %u too high\n",
207 tdb->allrecord_lock.count);
211 if (tdb->allrecord_lock.off != 1) {
212 tdb->log(tdb, TDB_DEBUG_ERROR, tdb->log_priv,
213 "tdb_allrecord_upgrade failed: already upgraded?\n");
219 if (tdb_brlock(tdb, F_WRLCK,
221 + (1ULL << tdb->header.v.hash_bits), 0,
222 TDB_LOCK_WAIT|TDB_LOCK_PROBE) == 0) {
223 tdb->allrecord_lock.ltype = F_WRLCK;
224 tdb->allrecord_lock.off = 0;
227 if (errno != EDEADLK) {
230 /* sleep for as short a time as we can - more portable than usleep() */
233 select(0, NULL, NULL, NULL, &tv);
235 tdb->log(tdb, TDB_DEBUG_WARNING, tdb->log_priv,
236 "tdb_allrecord_upgrade failed\n");
241 static struct tdb_lock_type *find_nestlock(struct tdb_context *tdb,
246 for (i=0; i<tdb->num_lockrecs; i++) {
247 if (tdb->lockrecs[i].off == offset) {
248 return &tdb->lockrecs[i];
254 /* lock an offset in the database. */
255 static int tdb_nest_lock(struct tdb_context *tdb, tdb_off_t offset, int ltype,
256 enum tdb_lock_flags flags)
258 struct tdb_lock_type *new_lck;
260 if (offset > TDB_HASH_LOCK_START + TDB_HASH_LOCK_RANGE + tdb->map_size / 8) {
261 tdb->ecode = TDB_ERR_LOCK;
262 tdb->log(tdb, TDB_DEBUG_FATAL, tdb->log_priv,
263 "tdb_nest_lock: invalid offset %llu ltype=%d\n",
264 (long long)offset, ltype);
268 if (tdb->flags & TDB_NOLOCK)
271 new_lck = find_nestlock(tdb, offset);
273 if (new_lck->ltype == F_RDLCK && ltype == F_WRLCK) {
274 tdb->ecode = TDB_ERR_LOCK;
275 tdb->log(tdb, TDB_DEBUG_FATAL, tdb->log_priv,
276 "tdb_nest_lock: offset %llu has read lock\n",
280 /* Just increment the struct, posix locks don't stack. */
285 if (tdb->num_lockrecs
286 && offset >= TDB_HASH_LOCK_START
287 && offset < TDB_HASH_LOCK_START + TDB_HASH_LOCK_RANGE) {
288 tdb->ecode = TDB_ERR_LOCK;
289 tdb->log(tdb, TDB_DEBUG_FATAL, tdb->log_priv,
290 "tdb_nest_lock: already have a hash lock?\n");
294 new_lck = (struct tdb_lock_type *)realloc(
296 sizeof(*tdb->lockrecs) * (tdb->num_lockrecs+1));
297 if (new_lck == NULL) {
298 tdb->ecode = TDB_ERR_OOM;
299 tdb->log(tdb, TDB_DEBUG_ERROR, tdb->log_priv,
300 "tdb_nest_lock: unable to allocate %llu lock struct",
301 (long long)(tdb->num_lockrecs + 1));
305 tdb->lockrecs = new_lck;
307 /* Since fcntl locks don't nest, we do a lock for the first one,
308 and simply bump the count for future ones */
309 if (tdb_brlock(tdb, ltype, offset, 1, flags)) {
313 tdb->lockrecs[tdb->num_lockrecs].off = offset;
314 tdb->lockrecs[tdb->num_lockrecs].count = 1;
315 tdb->lockrecs[tdb->num_lockrecs].ltype = ltype;
321 static int tdb_lock_and_recover(struct tdb_context *tdb)
327 /* We need to match locking order in transaction commit. */
328 if (tdb_brlock(tdb, F_WRLCK, FREELIST_TOP, 0, TDB_LOCK_WAIT)) {
332 if (tdb_brlock(tdb, F_WRLCK, OPEN_LOCK, 1, TDB_LOCK_WAIT)) {
333 tdb_brunlock(tdb, F_WRLCK, FREELIST_TOP, 0);
337 ret = tdb_transaction_recover(tdb);
339 tdb_brunlock(tdb, F_WRLCK, OPEN_LOCK, 1);
340 tdb_brunlock(tdb, F_WRLCK, FREELIST_TOP, 0);
349 static bool tdb_needs_recovery(struct tdb_context *tdb)
355 static int tdb_nest_unlock(struct tdb_context *tdb, tdb_off_t off, int ltype)
358 struct tdb_lock_type *lck;
360 if (tdb->flags & TDB_NOLOCK)
363 lck = find_nestlock(tdb, off);
364 if ((lck == NULL) || (lck->count == 0)) {
365 tdb->ecode = TDB_ERR_LOCK;
366 tdb->log(tdb, TDB_DEBUG_ERROR, tdb->log_priv,
367 "tdb_nest_unlock: no lock for %llu\n", (long long)off);
371 if (lck->count > 1) {
377 * This lock has count==1 left, so we need to unlock it in the
378 * kernel. We don't bother with decrementing the in-memory array
379 * element, we're about to overwrite it with the last array element
382 ret = tdb_brunlock(tdb, ltype, off, 1);
385 * Shrink the array by overwriting the element just unlocked with the
386 * last array element.
388 *lck = tdb->lockrecs[--tdb->num_lockrecs];
395 get the transaction lock
397 int tdb_transaction_lock(struct tdb_context *tdb, int ltype,
398 enum tdb_lock_flags lockflags)
400 return tdb_nest_lock(tdb, TRANSACTION_LOCK, ltype, lockflags);
404 release the transaction lock
406 int tdb_transaction_unlock(struct tdb_context *tdb, int ltype)
408 return tdb_nest_unlock(tdb, TRANSACTION_LOCK, ltype, false);
412 /* We only need to lock individual bytes, but Linux merges consecutive locks
413 * so we lock in contiguous ranges. */
414 static int tdb_lock_gradual(struct tdb_context *tdb,
415 int ltype, enum tdb_lock_flags flags,
416 tdb_off_t off, tdb_off_t len)
419 enum tdb_lock_flags nb_flags = (flags & ~TDB_LOCK_WAIT);
422 /* 0 would mean to end-of-file... */
424 /* Single hash. Just do blocking lock. */
425 return tdb_brlock(tdb, ltype, off, len, flags);
428 /* First we try non-blocking. */
429 ret = tdb_brlock(tdb, ltype, off, len, nb_flags);
434 /* Try locking first half, then second. */
435 ret = tdb_lock_gradual(tdb, ltype, flags, off, len / 2);
439 ret = tdb_lock_gradual(tdb, ltype, flags,
440 off + len / 2, len - len / 2);
442 tdb_brunlock(tdb, ltype, off, len / 2);
448 /* lock/unlock entire database. It can only be upgradable if you have some
449 * other way of guaranteeing exclusivity (ie. transaction write lock). */
450 int tdb_allrecord_lock(struct tdb_context *tdb, int ltype,
451 enum tdb_lock_flags flags, bool upgradable)
453 /* FIXME: There are no locks on read-only dbs */
454 if (tdb->read_only) {
455 tdb->ecode = TDB_ERR_LOCK;
456 tdb->log(tdb, TDB_DEBUG_ERROR, tdb->log_priv,
457 "tdb_allrecord_lock: read-only\n");
461 if (tdb->allrecord_lock.count
462 && (ltype == F_RDLCK || tdb->allrecord_lock.ltype == F_WRLCK)) {
463 tdb->allrecord_lock.count++;
467 if (tdb->allrecord_lock.count) {
468 /* a global lock of a different type exists */
469 tdb->ecode = TDB_ERR_LOCK;
470 tdb->log(tdb, TDB_DEBUG_ERROR, tdb->log_priv,
471 "tdb_allrecord_lock: already have %s lock\n",
472 tdb->allrecord_lock.ltype == F_RDLCK
477 if (tdb_has_locks(tdb)) {
478 /* can't combine global and chain locks */
479 tdb->ecode = TDB_ERR_LOCK;
480 tdb->log(tdb, TDB_DEBUG_ERROR, tdb->log_priv,
481 "tdb_allrecord_lock: already have chain lock\n");
485 if (upgradable && ltype != F_RDLCK) {
486 /* tdb error: you can't upgrade a write lock! */
487 tdb->ecode = TDB_ERR_LOCK;
488 tdb->log(tdb, TDB_DEBUG_ERROR, tdb->log_priv,
489 "tdb_allrecord_lock: can't upgrade a write lock\n");
494 /* Lock hashes, gradually. */
495 if (tdb_lock_gradual(tdb, ltype, flags, TDB_HASH_LOCK_START,
496 TDB_HASH_LOCK_RANGE)) {
497 if (!(flags & TDB_LOCK_PROBE)) {
498 tdb->log(tdb, TDB_DEBUG_ERROR, tdb->log_priv,
499 "tdb_allrecord_lock hashes failed (%s)\n",
505 /* Lock free lists: there to end of file. */
506 if (tdb_brlock(tdb, ltype, TDB_HASH_LOCK_START + TDB_HASH_LOCK_RANGE,
508 if (!(flags & TDB_LOCK_PROBE)) {
509 tdb->log(tdb, TDB_DEBUG_ERROR, tdb->log_priv,
510 "tdb_allrecord_lock freelist failed (%s)\n",
513 tdb_brunlock(tdb, ltype, TDB_HASH_LOCK_START,
514 TDB_HASH_LOCK_RANGE);
518 tdb->allrecord_lock.count = 1;
519 /* If it's upgradable, it's actually exclusive so we can treat
520 * it as a write lock. */
521 tdb->allrecord_lock.ltype = upgradable ? F_WRLCK : ltype;
522 tdb->allrecord_lock.off = upgradable;
524 /* Now check for needing recovery. */
525 if (unlikely(tdb_needs_recovery(tdb))) {
526 tdb_allrecord_unlock(tdb, ltype);
527 if (tdb_lock_and_recover(tdb) == -1) {
536 int tdb_lock_open(struct tdb_context *tdb)
538 return tdb_nest_lock(tdb, TDB_OPEN_LOCK, F_WRLCK, TDB_LOCK_WAIT);
541 void tdb_unlock_open(struct tdb_context *tdb)
543 tdb_nest_unlock(tdb, TDB_OPEN_LOCK, F_WRLCK);
546 int tdb_lock_expand(struct tdb_context *tdb, int ltype)
548 return tdb_nest_lock(tdb, TDB_EXPANSION_LOCK, ltype, TDB_LOCK_WAIT);
551 void tdb_unlock_expand(struct tdb_context *tdb, int ltype)
553 tdb_nest_unlock(tdb, TDB_EXPANSION_LOCK, ltype);
556 /* unlock entire db */
557 int tdb_allrecord_unlock(struct tdb_context *tdb, int ltype)
559 /* FIXME: There are no locks on read-only dbs */
560 if (tdb->read_only) {
561 tdb->ecode = TDB_ERR_LOCK;
562 tdb->log(tdb, TDB_DEBUG_ERROR, tdb->log_priv,
563 "tdb_allrecord_unlock: read-only\n");
567 if (tdb->allrecord_lock.count == 0) {
568 tdb->ecode = TDB_ERR_LOCK;
569 tdb->log(tdb, TDB_DEBUG_ERROR, tdb->log_priv,
570 "tdb_allrecord_unlock: not locked!\n");
574 /* Upgradable locks are marked as write locks. */
575 if (tdb->allrecord_lock.ltype != ltype
576 && (!tdb->allrecord_lock.off || ltype != F_RDLCK)) {
577 tdb->ecode = TDB_ERR_LOCK;
578 tdb->log(tdb, TDB_DEBUG_ERROR, tdb->log_priv,
579 "tdb_allrecord_unlock: have %s lock\n",
580 tdb->allrecord_lock.ltype == F_RDLCK
585 if (tdb->allrecord_lock.count > 1) {
586 tdb->allrecord_lock.count--;
590 tdb->allrecord_lock.count = 0;
591 tdb->allrecord_lock.ltype = 0;
593 return tdb_brunlock(tdb, ltype, TDB_HASH_LOCK_START, 0);
596 bool tdb_has_expansion_lock(struct tdb_context *tdb)
598 return find_nestlock(tdb, TDB_EXPANSION_LOCK) != NULL;
601 bool tdb_has_locks(struct tdb_context *tdb)
603 return tdb->allrecord_lock.count || tdb->num_lockrecs;
607 /* lock entire database with write lock */
608 int tdb_lockall(struct tdb_context *tdb)
610 tdb_trace(tdb, "tdb_lockall");
611 return tdb_allrecord_lock(tdb, F_WRLCK, TDB_LOCK_WAIT, false);
614 /* lock entire database with write lock - nonblocking varient */
615 int tdb_lockall_nonblock(struct tdb_context *tdb)
617 int ret = tdb_allrecord_lock(tdb, F_WRLCK, TDB_LOCK_NOWAIT, false);
618 tdb_trace_ret(tdb, "tdb_lockall_nonblock", ret);
622 /* unlock entire database with write lock */
623 int tdb_unlockall(struct tdb_context *tdb)
625 tdb_trace(tdb, "tdb_unlockall");
626 return tdb_allrecord_unlock(tdb, F_WRLCK);
629 /* lock entire database with read lock */
630 int tdb_lockall_read(struct tdb_context *tdb)
632 tdb_trace(tdb, "tdb_lockall_read");
633 return tdb_allrecord_lock(tdb, F_RDLCK, TDB_LOCK_WAIT, false);
636 /* lock entire database with read lock - nonblock varient */
637 int tdb_lockall_read_nonblock(struct tdb_context *tdb)
639 int ret = tdb_allrecord_lock(tdb, F_RDLCK, TDB_LOCK_NOWAIT, false);
640 tdb_trace_ret(tdb, "tdb_lockall_read_nonblock", ret);
644 /* unlock entire database with read lock */
645 int tdb_unlockall_read(struct tdb_context *tdb)
647 tdb_trace(tdb, "tdb_unlockall_read");
648 return tdb_allrecord_unlock(tdb, F_RDLCK);
652 static bool tdb_has_free_lock(struct tdb_context *tdb)
656 for (i=0; i<tdb->num_lockrecs; i++) {
657 if (tdb->lockrecs[i].off
658 > TDB_HASH_LOCK_START + TDB_HASH_LOCK_RANGE)
664 int tdb_lock_hashes(struct tdb_context *tdb,
666 tdb_len_t hash_range,
667 int ltype, enum tdb_lock_flags waitflag)
669 /* FIXME: Do this properly, using hlock_range */
670 unsigned lock = TDB_HASH_LOCK_START
671 + (hash_lock >> (64 - TDB_HASH_LOCK_RANGE_BITS));
673 /* a allrecord lock allows us to avoid per chain locks */
674 if (tdb->allrecord_lock.count &&
675 (ltype == tdb->allrecord_lock.ltype || ltype == F_RDLCK)) {
679 if (tdb->allrecord_lock.count) {
680 tdb->ecode = TDB_ERR_LOCK;
681 tdb->log(tdb, TDB_DEBUG_ERROR, tdb->log_priv,
682 "tdb_lock_hashes: have %s allrecordlock\n",
683 tdb->allrecord_lock.ltype == F_RDLCK
688 if (tdb_has_free_lock(tdb)) {
689 tdb->ecode = TDB_ERR_LOCK;
690 tdb->log(tdb, TDB_DEBUG_ERROR, tdb->log_priv,
691 "tdb_lock_hashes: have free lock already\n");
695 if (tdb_has_expansion_lock(tdb)) {
696 tdb->ecode = TDB_ERR_LOCK;
697 tdb->log(tdb, TDB_DEBUG_ERROR, tdb->log_priv,
698 "tdb_lock_hashes: have expansion lock already\n");
702 return tdb_nest_lock(tdb, lock, ltype, waitflag);
705 int tdb_unlock_hashes(struct tdb_context *tdb,
707 tdb_len_t hash_range, int ltype)
709 unsigned lock = TDB_HASH_LOCK_START
710 + (hash_lock >> (64 - TDB_HASH_LOCK_RANGE_BITS));
712 /* a allrecord lock allows us to avoid per chain locks */
713 if (tdb->allrecord_lock.count) {
714 if (tdb->allrecord_lock.ltype == F_RDLCK
715 && ltype == F_WRLCK) {
716 tdb->ecode = TDB_ERR_LOCK;
717 tdb->log(tdb, TDB_DEBUG_FATAL, tdb->log_priv,
718 "tdb_unlock_hashes RO allrecord!\n");
724 return tdb_nest_unlock(tdb, lock, ltype);
727 /* Hash locks use TDB_HASH_LOCK_START + the next 30 bits.
728 * Then we begin; bucket offsets are sizeof(tdb_len_t) apart, so we divide.
729 * The result is that on 32 bit systems we don't use lock values > 2^31 on
730 * files that are less than 4GB.
732 static tdb_off_t free_lock_off(tdb_off_t b_off)
734 return TDB_HASH_LOCK_START + TDB_HASH_LOCK_RANGE
735 + b_off / sizeof(tdb_off_t);
738 int tdb_lock_free_bucket(struct tdb_context *tdb, tdb_off_t b_off,
739 enum tdb_lock_flags waitflag)
741 assert(b_off >= sizeof(struct tdb_header));
743 /* a allrecord lock allows us to avoid per chain locks */
744 if (tdb->allrecord_lock.count) {
745 if (tdb->allrecord_lock.ltype == F_WRLCK)
747 tdb->ecode = TDB_ERR_LOCK;
748 tdb->log(tdb, TDB_DEBUG_FATAL, tdb->log_priv,
749 "tdb_lock_free_bucket with RO allrecordlock!\n");
754 if (tdb_has_expansion_lock(tdb)) {
755 tdb->ecode = TDB_ERR_LOCK;
756 tdb->log(tdb, TDB_DEBUG_ERROR, tdb->log_priv,
757 "tdb_lock_free_bucket: have expansion lock already\n");
762 return tdb_nest_lock(tdb, free_lock_off(b_off), F_WRLCK, waitflag);
765 void tdb_unlock_free_bucket(struct tdb_context *tdb, tdb_off_t b_off)
767 if (tdb->allrecord_lock.count)
770 tdb_nest_unlock(tdb, free_lock_off(b_off), F_WRLCK);
774 /* lock/unlock one hash chain, non-blocking. This is meant to be used
775 to reduce contention - it cannot guarantee how many records will be
777 int tdb_chainlock_nonblock(struct tdb_context *tdb, TDB_DATA key)
779 return chainlock(tdb, &key, F_WRLCK, TDB_LOCK_NOWAIT,
780 "tdb_chainlock_nonblock");
783 int tdb_chainlock_read(struct tdb_context *tdb, TDB_DATA key)
785 return chainlock(tdb, &key, F_RDLCK, TDB_LOCK_WAIT,
786 "tdb_chainlock_read");
789 int tdb_chainunlock_read(struct tdb_context *tdb, TDB_DATA key)
791 uint64_t h = tdb_hash(tdb, key.dptr, key.dsize);
792 tdb_trace_1rec(tdb, "tdb_chainunlock_read", key);
793 return tdb_unlock_list(tdb, h & ((1ULL << tdb->header.v.hash_bits)-1),
797 /* record lock stops delete underneath */
798 int tdb_lock_record(struct tdb_context *tdb, tdb_off_t off)
800 if (tdb->allrecord_lock.count) {
803 return off ? tdb_brlock(tdb, F_RDLCK, off, 1, TDB_LOCK_WAIT) : 0;
807 Write locks override our own fcntl readlocks, so check it here.
808 Note this is meant to be F_SETLK, *not* F_SETLKW, as it's not
809 an error to fail to get the lock here.
811 int tdb_write_lock_record(struct tdb_context *tdb, tdb_off_t off)
813 struct tdb_traverse_lock *i;
814 for (i = &tdb->travlocks; i; i = i->next)
817 if (tdb->allrecord_lock.count) {
818 if (tdb->allrecord_lock.ltype == F_WRLCK) {
823 return tdb_brlock(tdb, F_WRLCK, off, 1, TDB_LOCK_NOWAIT|TDB_LOCK_PROBE);
826 int tdb_write_unlock_record(struct tdb_context *tdb, tdb_off_t off)
828 if (tdb->allrecord_lock.count) {
831 return tdb_brunlock(tdb, F_WRLCK, off, 1);
834 /* fcntl locks don't stack: avoid unlocking someone else's */
835 int tdb_unlock_record(struct tdb_context *tdb, tdb_off_t off)
837 struct tdb_traverse_lock *i;
840 if (tdb->allrecord_lock.count) {
846 for (i = &tdb->travlocks; i; i = i->next)
849 return (count == 1 ? tdb_brunlock(tdb, F_RDLCK, off, 1) : 0);
852 /* The transaction code uses this to remove all locks. */
853 void tdb_release_transaction_locks(struct tdb_context *tdb)
857 if (tdb->allrecord_lock.count != 0) {
858 tdb_off_t hash_size, free_size;
860 hash_size = (1ULL << tdb->header.v.hash_bits)
862 free_size = tdb->header.v.free_zones
863 * (tdb->header.v.free_buckets + 1) * sizeof(tdb_off_t);
865 tdb_brunlock(tdb, tdb->allrecord_lock.ltype,
866 tdb->header.v.hash_off, hash_size);
867 tdb_brunlock(tdb, tdb->allrecord_lock.ltype,
868 tdb->header.v.free_off, free_size);
869 tdb->allrecord_lock.count = 0;
870 tdb->allrecord_lock.ltype = 0;
873 for (i = 0; i<tdb->num_lockrecs; i++) {
874 struct tdb_lock_type *lck = &tdb->lockrecs[i];
876 tdb_brunlock(tdb, lck->ltype, lck->off, 1);
878 tdb->num_lockrecs = 0;
879 SAFE_FREE(tdb->lockrecs);
880 tdb->header_uptodate = false;
884 void tdb_lock_init(struct tdb_context *tdb)
886 tdb->num_lockrecs = 0;
887 tdb->lockrecs = NULL;
888 tdb->allrecord_lock.count = 0;