return fcntl(tdb->fd, F_SETLKW, &fl);
}
+/* list -1 is the alloc list, otherwise a hash chain. */
+static tdb_off_t lock_offset(int list)
+{
+ return FREELIST_TOP + 4*list;
+}
+
/* a byte range locking function - return 0 on success
this functions locks/unlocks 1 byte at the specified offset.
return -1;
}
+ /* Sanity check */
+ if (tdb->transaction && offset >= lock_offset(-1) && len != 0) {
+ tdb->ecode = TDB_ERR_RDONLY;
+ TDB_LOG((tdb, TDB_DEBUG_TRACE, "tdb_brlock attempted in transaction at offset %d rw_type=%d flags=%d len=%d\n",
+ offset, rw_type, flags, (int)len));
+ return -1;
+ }
+
do {
ret = fcntl_lock(tdb, rw_type, offset, len,
flags & TDB_LOCK_WAIT);
deadlock detection and claim a deadlock when progress can be
made. For those OSes we may loop for a while.
*/
-int tdb_brlock_upgrade(struct tdb_context *tdb, tdb_off_t offset, size_t len)
+int tdb_allrecord_upgrade(struct tdb_context *tdb)
{
int count = 1000;
+
+ if (tdb->allrecord_lock.count != 1) {
+ TDB_LOG((tdb, TDB_DEBUG_ERROR,
+ "tdb_allrecord_upgrade failed: count %u too high\n",
+ tdb->allrecord_lock.count));
+ return -1;
+ }
+
+ if (tdb->allrecord_lock.off != 1) {
+ TDB_LOG((tdb, TDB_DEBUG_ERROR,
+ "tdb_allrecord_upgrade failed: already upgraded?\n"));
+ return -1;
+ }
+
while (count--) {
struct timeval tv;
- if (tdb_brlock(tdb, F_WRLCK, offset, len,
+ if (tdb_brlock(tdb, F_WRLCK, FREELIST_TOP, 0,
TDB_LOCK_WAIT|TDB_LOCK_PROBE) == 0) {
+ tdb->allrecord_lock.ltype = F_WRLCK;
+ tdb->allrecord_lock.off = 0;
return 0;
}
if (errno != EDEADLK) {
tv.tv_usec = 1;
select(0, NULL, NULL, NULL, &tv);
}
- TDB_LOG((tdb, TDB_DEBUG_TRACE,"tdb_brlock_upgrade failed at offset %d\n", offset));
+ TDB_LOG((tdb, TDB_DEBUG_TRACE,"tdb_allrecord_upgrade failed\n"));
return -1;
}
-/* list -1 is the alloc list, otherwise a hash chain. */
-static tdb_off_t lock_offset(int list)
-{
- return FREELIST_TOP + 4*list;
-}
-
static struct tdb_lock_type *find_nestlock(struct tdb_context *tdb,
tdb_off_t offset)
{
/* Since fcntl locks don't nest, we do a lock for the first one,
and simply bump the count for future ones */
- if (tdb->methods->brlock(tdb, ltype, offset, 1, flags)) {
+ if (tdb_brlock(tdb, ltype, offset, 1, flags)) {
return -1;
}
return 0;
}
-/* lock a list in the database. list -1 is the alloc list */
-int tdb_lock(struct tdb_context *tdb, int list, int ltype)
+static int tdb_lock_and_recover(struct tdb_context *tdb)
{
int ret;
+ /* We need to match locking order in transaction commit. */
+ if (tdb_brlock(tdb, F_WRLCK, FREELIST_TOP, 0, TDB_LOCK_WAIT)) {
+ return -1;
+ }
+
+ if (tdb_brlock(tdb, F_WRLCK, OPEN_LOCK, 1, TDB_LOCK_WAIT)) {
+ tdb_brunlock(tdb, F_WRLCK, FREELIST_TOP, 0);
+ return -1;
+ }
+
+ ret = tdb_transaction_recover(tdb);
+
+ tdb_brunlock(tdb, F_WRLCK, OPEN_LOCK, 1);
+ tdb_brunlock(tdb, F_WRLCK, FREELIST_TOP, 0);
+
+ return ret;
+}
+
+static bool have_data_locks(const struct tdb_context *tdb)
+{
+ unsigned int i;
+
+ for (i = 0; i < tdb->num_lockrecs; i++) {
+ if (tdb->lockrecs[i].off >= lock_offset(-1))
+ return true;
+ }
+ return false;
+}
+
+static int tdb_lock_list(struct tdb_context *tdb, int list, int ltype,
+ enum tdb_lock_flags waitflag)
+{
+ int ret;
+ bool check = false;
+
/* a allrecord lock allows us to avoid per chain locks */
if (tdb->allrecord_lock.count &&
(ltype == tdb->allrecord_lock.ltype || ltype == F_RDLCK)) {
tdb->ecode = TDB_ERR_LOCK;
ret = -1;
} else {
- ret = tdb_nest_lock(tdb, lock_offset(list), ltype,
- TDB_LOCK_WAIT);
+ /* Only check when we grab first data lock. */
+ check = !have_data_locks(tdb);
+ ret = tdb_nest_lock(tdb, lock_offset(list), ltype, waitflag);
+
+ if (ret == 0 && check && tdb_needs_recovery(tdb)) {
+ tdb_nest_unlock(tdb, lock_offset(list), ltype, false);
+
+ if (tdb_lock_and_recover(tdb) == -1) {
+ return -1;
+ }
+ return tdb_lock_list(tdb, list, ltype, waitflag);
+ }
}
+ return ret;
+}
+
+/* lock a list in the database. list -1 is the alloc list */
+int tdb_lock(struct tdb_context *tdb, int list, int ltype)
+{
+ int ret;
+
+ ret = tdb_lock_list(tdb, list, ltype, TDB_LOCK_WAIT);
if (ret) {
TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_lock failed on list %d "
"ltype=%d (%s)\n", list, ltype, strerror(errno)));
/* lock a list in the database. list -1 is the alloc list. non-blocking lock */
int tdb_lock_nonblock(struct tdb_context *tdb, int list, int ltype)
{
- /* a allrecord lock allows us to avoid per chain locks */
- if (tdb->allrecord_lock.count &&
- (ltype == tdb->allrecord_lock.ltype || ltype == F_RDLCK)) {
- return 0;
- }
-
- if (tdb->allrecord_lock.count) {
- tdb->ecode = TDB_ERR_LOCK;
- return -1;
- }
-
- return tdb_nest_lock(tdb, lock_offset(list), ltype, TDB_LOCK_NOWAIT);
+ return tdb_lock_list(tdb, list, ltype, TDB_LOCK_NOWAIT);
}
if (mark_lock) {
ret = 0;
} else {
- ret = tdb->methods->brunlock(tdb, ltype, offset, 1);
+ ret = tdb_brunlock(tdb, ltype, offset, 1);
}
/*
}
-
-
-/* lock/unlock entire database */
-static int _tdb_lockall(struct tdb_context *tdb, int ltype,
- enum tdb_lock_flags flags)
+/* lock/unlock entire database. It can only be upgradable if you have some
+ * other way of guaranteeing exclusivity (ie. transaction write lock). */
+int tdb_allrecord_lock(struct tdb_context *tdb, int ltype,
+ enum tdb_lock_flags flags, bool upgradable)
{
/* There are no locks on read-only dbs */
if (tdb->read_only || tdb->traverse_read) {
return -1;
}
- if (tdb->methods->brlock(tdb, ltype,
- FREELIST_TOP, 4*tdb->header.hash_size,
- flags)) {
+ if (upgradable && ltype != F_RDLCK) {
+ /* tdb error: you can't upgrade a write lock! */
+ tdb->ecode = TDB_ERR_LOCK;
+ return -1;
+ }
+
+ if (tdb_brlock(tdb, ltype, FREELIST_TOP, 0, flags)) {
if (flags & TDB_LOCK_WAIT) {
TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_lockall failed (%s)\n", strerror(errno)));
}
}
tdb->allrecord_lock.count = 1;
- tdb->allrecord_lock.ltype = ltype;
+ /* If it's upgradable, it's actually exclusive so we can treat
+ * it as a write lock. */
+ tdb->allrecord_lock.ltype = upgradable ? F_WRLCK : ltype;
+ tdb->allrecord_lock.off = upgradable;
+
+ if (tdb_needs_recovery(tdb)) {
+ bool mark = flags & TDB_LOCK_MARK_ONLY;
+ tdb_allrecord_unlock(tdb, ltype, mark);
+ if (mark) {
+ tdb->ecode = TDB_ERR_LOCK;
+ TDB_LOG((tdb, TDB_DEBUG_ERROR,
+ "tdb_lockall_mark cannot do recovery\n"));
+ return -1;
+ }
+ if (tdb_lock_and_recover(tdb) == -1) {
+ return -1;
+ }
+ return tdb_allrecord_lock(tdb, ltype, flags, upgradable);
+ }
return 0;
}
/* unlock entire db */
-static int _tdb_unlockall(struct tdb_context *tdb, int ltype, bool mark_lock)
+int tdb_allrecord_unlock(struct tdb_context *tdb, int ltype, bool mark_lock)
{
/* There are no locks on read-only dbs */
if (tdb->read_only || tdb->traverse_read) {
return -1;
}
- if (tdb->allrecord_lock.ltype != ltype || tdb->allrecord_lock.count == 0) {
+ if (tdb->allrecord_lock.count == 0) {
+ tdb->ecode = TDB_ERR_LOCK;
+ return -1;
+ }
+
+ /* Upgradable locks are marked as write locks. */
+ if (tdb->allrecord_lock.ltype != ltype
+ && (!tdb->allrecord_lock.off || ltype != F_RDLCK)) {
tdb->ecode = TDB_ERR_LOCK;
return -1;
}
return 0;
}
- if (!mark_lock &&
- tdb->methods->brunlock(tdb, ltype,
- FREELIST_TOP, 4*tdb->header.hash_size)) {
+ if (!mark_lock && tdb_brunlock(tdb, ltype, FREELIST_TOP, 0)) {
TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_unlockall failed (%s)\n", strerror(errno)));
return -1;
}
int tdb_lockall(struct tdb_context *tdb)
{
tdb_trace(tdb, "tdb_lockall");
- return _tdb_lockall(tdb, F_WRLCK, TDB_LOCK_WAIT);
+ return tdb_allrecord_lock(tdb, F_WRLCK, TDB_LOCK_WAIT, false);
}
/* lock entire database with write lock - mark only */
int tdb_lockall_mark(struct tdb_context *tdb)
{
tdb_trace(tdb, "tdb_lockall_mark");
- return _tdb_lockall(tdb, F_WRLCK, TDB_LOCK_MARK_ONLY);
+ return tdb_allrecord_lock(tdb, F_WRLCK, TDB_LOCK_MARK_ONLY, false);
}
/* unlock entire database with write lock - unmark only */
int tdb_lockall_unmark(struct tdb_context *tdb)
{
tdb_trace(tdb, "tdb_lockall_unmark");
- return _tdb_unlockall(tdb, F_WRLCK, true);
+ return tdb_allrecord_unlock(tdb, F_WRLCK, true);
}
/* lock entire database with write lock - nonblocking varient */
int tdb_lockall_nonblock(struct tdb_context *tdb)
{
- int ret = _tdb_lockall(tdb, F_WRLCK, TDB_LOCK_NOWAIT);
+ int ret = tdb_allrecord_lock(tdb, F_WRLCK, TDB_LOCK_NOWAIT, false);
tdb_trace_ret(tdb, "tdb_lockall_nonblock", ret);
return ret;
}
int tdb_unlockall(struct tdb_context *tdb)
{
tdb_trace(tdb, "tdb_unlockall");
- return _tdb_unlockall(tdb, F_WRLCK, false);
+ return tdb_allrecord_unlock(tdb, F_WRLCK, false);
}
/* lock entire database with read lock */
int tdb_lockall_read(struct tdb_context *tdb)
{
tdb_trace(tdb, "tdb_lockall_read");
- return _tdb_lockall(tdb, F_RDLCK, TDB_LOCK_WAIT);
+ return tdb_allrecord_lock(tdb, F_RDLCK, TDB_LOCK_WAIT, false);
}
/* lock entire database with read lock - nonblock varient */
int tdb_lockall_read_nonblock(struct tdb_context *tdb)
{
- int ret = _tdb_lockall(tdb, F_RDLCK, TDB_LOCK_NOWAIT);
+ int ret = tdb_allrecord_lock(tdb, F_RDLCK, TDB_LOCK_NOWAIT, false);
tdb_trace_ret(tdb, "tdb_lockall_read_nonblock", ret);
return ret;
}
int tdb_unlockall_read(struct tdb_context *tdb)
{
tdb_trace(tdb, "tdb_unlockall_read");
- return _tdb_unlockall(tdb, F_RDLCK, false);
+ return tdb_allrecord_unlock(tdb, F_RDLCK, false);
}
/* lock/unlock one hash chain. This is meant to be used to reduce
if (tdb->allrecord_lock.count) {
return 0;
}
- return off ? tdb->methods->brlock(tdb, F_RDLCK, off, 1, TDB_LOCK_WAIT) : 0;
+ return off ? tdb_brlock(tdb, F_RDLCK, off, 1, TDB_LOCK_WAIT) : 0;
}
/*
for (i = &tdb->travlocks; i; i = i->next)
if (i->off == off)
return -1;
- return tdb->methods->brlock(tdb, F_WRLCK, off, 1, TDB_LOCK_NOWAIT|TDB_LOCK_PROBE);
+ if (tdb->allrecord_lock.count) {
+ if (tdb->allrecord_lock.ltype == F_WRLCK) {
+ return 0;
+ }
+ return -1;
+ }
+ return tdb_brlock(tdb, F_WRLCK, off, 1, TDB_LOCK_NOWAIT|TDB_LOCK_PROBE);
}
int tdb_write_unlock_record(struct tdb_context *tdb, tdb_off_t off)
{
- return tdb->methods->brunlock(tdb, F_WRLCK, off, 1);
+ if (tdb->allrecord_lock.count) {
+ return 0;
+ }
+ return tdb_brunlock(tdb, F_WRLCK, off, 1);
}
/* fcntl locks don't stack: avoid unlocking someone else's */
for (i = &tdb->travlocks; i; i = i->next)
if (i->off == off)
count++;
- return (count == 1 ? tdb->methods->brunlock(tdb, F_RDLCK, off, 1) : 0);
+ return (count == 1 ? tdb_brunlock(tdb, F_RDLCK, off, 1) : 0);
}
bool tdb_have_extra_locks(struct tdb_context *tdb)
{
unsigned int extra = tdb->num_lockrecs;
- if (tdb->allrecord_lock.count) {
+ /* A transaction holds the lock for all records. */
+ if (!tdb->transaction && tdb->allrecord_lock.count) {
return true;
}
unsigned int i, extra = 0;
if (tdb->allrecord_lock.count != 0) {
- tdb_brunlock(tdb, tdb->allrecord_lock.ltype,
- FREELIST_TOP, 4*tdb->header.hash_size);
+ tdb_brunlock(tdb, tdb->allrecord_lock.ltype, FREELIST_TOP, 0);
tdb->allrecord_lock.count = 0;
}