#include "tdb_private.h"
-#define TDB_MARK_LOCK 0x80000000
-
void tdb_setalarm_sigptr(struct tdb_context *tdb, volatile sig_atomic_t *ptr)
{
tdb->interrupt_sig_ptr = ptr;
}
+static int fcntl_lock(struct tdb_context *tdb,
+ int rw, off_t off, off_t len, bool waitflag)
+{
+ struct flock fl;
+
+ fl.l_type = rw;
+ fl.l_whence = SEEK_SET;
+ fl.l_start = off;
+ fl.l_len = len;
+ fl.l_pid = 0;
+
+ if (waitflag)
+ return fcntl(tdb->fd, F_SETLKW, &fl);
+ else
+ return fcntl(tdb->fd, F_SETLK, &fl);
+}
+
+static int fcntl_unlock(struct tdb_context *tdb, int rw, off_t off, off_t len)
+{
+ struct flock fl;
+#if 0 /* Check they matched up locks and unlocks correctly. */
+ char line[80];
+ FILE *locks;
+ bool found = false;
+
+ locks = fopen("/proc/locks", "r");
+
+ while (fgets(line, 80, locks)) {
+ char *p;
+ int type, start, l;
+
+ /* eg. 1: FLOCK ADVISORY WRITE 2440 08:01:2180826 0 EOF */
+ p = strchr(line, ':') + 1;
+ if (strncmp(p, " POSIX ADVISORY ", strlen(" POSIX ADVISORY ")))
+ continue;
+ p += strlen(" FLOCK ADVISORY ");
+ if (strncmp(p, "READ ", strlen("READ ")) == 0)
+ type = F_RDLCK;
+ else if (strncmp(p, "WRITE ", strlen("WRITE ")) == 0)
+ type = F_WRLCK;
+ else
+ abort();
+ p += 6;
+ if (atoi(p) != getpid())
+ continue;
+ p = strchr(strchr(p, ' ') + 1, ' ') + 1;
+ start = atoi(p);
+ p = strchr(p, ' ') + 1;
+ if (strncmp(p, "EOF", 3) == 0)
+ l = 0;
+ else
+ l = atoi(p) - start + 1;
+
+ if (off == start) {
+ if (len != l) {
+ fprintf(stderr, "Len %u should be %u: %s",
+ (int)len, l, line);
+ abort();
+ }
+ if (type != rw) {
+ fprintf(stderr, "Type %s wrong: %s",
+ rw == F_RDLCK ? "READ" : "WRITE", line);
+ abort();
+ }
+ found = true;
+ break;
+ }
+ }
+
+ if (!found) {
+ fprintf(stderr, "Unlock on %u@%u not found!\n",
+ (int)off, (int)len);
+ abort();
+ }
+
+ fclose(locks);
+#endif
+
+ fl.l_type = F_UNLCK;
+ fl.l_whence = SEEK_SET;
+ fl.l_start = off;
+ fl.l_len = len;
+ fl.l_pid = 0;
+
+ 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.
note that a len of zero means lock to end of file
*/
-int tdb_brlock(struct tdb_context *tdb, tdb_off_t offset,
- int rw_type, int lck_type, int probe, size_t len)
+int tdb_brlock(struct tdb_context *tdb,
+ int rw_type, tdb_off_t offset, size_t len,
+ enum tdb_lock_flags flags)
{
- struct flock fl;
int ret;
if (tdb->flags & TDB_NOLOCK) {
return 0;
}
+ if (flags & TDB_LOCK_MARK_ONLY) {
+ return 0;
+ }
+
if ((rw_type == F_WRLCK) && (tdb->read_only || tdb->traverse_read)) {
tdb->ecode = TDB_ERR_RDONLY;
return -1;
}
- fl.l_type = rw_type;
- fl.l_whence = SEEK_SET;
- fl.l_start = offset;
- fl.l_len = len;
- fl.l_pid = 0;
-
do {
- ret = fcntl(tdb->fd,lck_type,&fl);
-
+ ret = fcntl_lock(tdb, rw_type, offset, len,
+ flags & TDB_LOCK_WAIT);
/* Check for a sigalarm break. */
if (ret == -1 && errno == EINTR &&
tdb->interrupt_sig_ptr &&
} while (ret == -1 && errno == EINTR);
if (ret == -1) {
+ tdb->ecode = TDB_ERR_LOCK;
/* Generic lock error. errno set by fcntl.
* EAGAIN is an expected return from non-blocking
* locks. */
- if (!probe && lck_type != F_SETLK) {
- /* Ensure error code is set for log fun to examine. */
- tdb->ecode = TDB_ERR_LOCK;
- TDB_LOG((tdb, TDB_DEBUG_TRACE,"tdb_brlock failed (fd=%d) at offset %d rw_type=%d lck_type=%d len=%d\n",
- tdb->fd, offset, rw_type, lck_type, (int)len));
+ if (!(flags & TDB_LOCK_PROBE) && errno != EAGAIN) {
+ TDB_LOG((tdb, TDB_DEBUG_TRACE,"tdb_brlock failed (fd=%d) at offset %d rw_type=%d flags=%d len=%d\n",
+ tdb->fd, offset, rw_type, flags, (int)len));
}
- return TDB_ERRCODE(TDB_ERR_LOCK, -1);
+ return -1;
}
return 0;
}
+int tdb_brunlock(struct tdb_context *tdb,
+ int rw_type, tdb_off_t offset, size_t len)
+{
+ int ret;
+
+ if (tdb->flags & TDB_NOLOCK) {
+ return 0;
+ }
+
+ do {
+ ret = fcntl_unlock(tdb, rw_type, offset, len);
+ } while (ret == -1 && errno == EINTR);
+
+ if (ret == -1) {
+ TDB_LOG((tdb, TDB_DEBUG_TRACE,"tdb_brunlock failed (fd=%d) at offset %d rw_type=%d len=%d\n",
+ tdb->fd, offset, rw_type, (int)len));
+ }
+ return ret;
+}
/*
upgrade a read lock to a write lock. This needs to be handled in a
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, offset, F_WRLCK, F_SETLKW, 1, len) == 0) {
+ 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;
}
-
-/* lock a list in the database. list -1 is the alloc list */
-static int _tdb_lock(struct tdb_context *tdb, int list, int ltype, int op)
+static struct tdb_lock_type *find_nestlock(struct tdb_context *tdb,
+ tdb_off_t offset)
{
- struct tdb_lock_type *new_lck;
- int i;
- bool mark_lock = ((ltype & TDB_MARK_LOCK) == TDB_MARK_LOCK);
-
- ltype &= ~TDB_MARK_LOCK;
+ unsigned int i;
- /* a global lock allows us to avoid per chain locks */
- if (tdb->global_lock.count &&
- (ltype == tdb->global_lock.ltype || ltype == F_RDLCK)) {
- return 0;
+ for (i=0; i<tdb->num_lockrecs; i++) {
+ if (tdb->lockrecs[i].off == offset) {
+ return &tdb->lockrecs[i];
+ }
}
+ return NULL;
+}
- if (tdb->global_lock.count) {
- return TDB_ERRCODE(TDB_ERR_LOCK, -1);
- }
+/* lock an offset in the database. */
+int tdb_nest_lock(struct tdb_context *tdb, uint32_t offset, int ltype,
+ enum tdb_lock_flags flags)
+{
+ struct tdb_lock_type *new_lck;
- if (list < -1 || list >= (int)tdb->header.hash_size) {
- TDB_LOG((tdb, TDB_DEBUG_ERROR,"tdb_lock: invalid list %d for ltype=%d\n",
- list, ltype));
+ if (offset >= lock_offset(tdb->header.hash_size)) {
+ tdb->ecode = TDB_ERR_LOCK;
+ TDB_LOG((tdb, TDB_DEBUG_ERROR,"tdb_lock: invalid offset %u for ltype=%d\n",
+ offset, ltype));
return -1;
}
if (tdb->flags & TDB_NOLOCK)
return 0;
- for (i=0; i<tdb->num_lockrecs; i++) {
- if (tdb->lockrecs[i].list == list) {
- if (tdb->lockrecs[i].count == 0) {
- /*
- * Can't happen, see tdb_unlock(). It should
- * be an assert.
- */
- TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_lock: "
- "lck->count == 0 for list %d", list));
- }
- /*
- * Just increment the in-memory struct, posix locks
- * don't stack.
- */
- tdb->lockrecs[i].count++;
- return 0;
- }
+ new_lck = find_nestlock(tdb, offset);
+ if (new_lck) {
+ /*
+ * Just increment the in-memory struct, posix locks
+ * don't stack.
+ */
+ new_lck->count++;
+ return 0;
}
new_lck = (struct tdb_lock_type *)realloc(
/* Since fcntl locks don't nest, we do a lock for the first one,
and simply bump the count for future ones */
- if (!mark_lock &&
- tdb->methods->tdb_brlock(tdb,FREELIST_TOP+4*list, ltype, op,
- 0, 1)) {
+ if (tdb_brlock(tdb, ltype, offset, 1, flags)) {
return -1;
}
- tdb->num_locks++;
-
- tdb->lockrecs[tdb->num_lockrecs].list = list;
+ tdb->lockrecs[tdb->num_lockrecs].off = offset;
tdb->lockrecs[tdb->num_lockrecs].count = 1;
tdb->lockrecs[tdb->num_lockrecs].ltype = ltype;
- tdb->num_lockrecs += 1;
+ tdb->num_lockrecs++;
return 0;
}
+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)) {
+ return 0;
+ }
+
+ if (tdb->allrecord_lock.count) {
+ tdb->ecode = TDB_ERR_LOCK;
+ ret = -1;
+ } else {
+ /* 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(tdb, list, ltype, F_SETLKW);
+
+ 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)
{
- return _tdb_lock(tdb, list, ltype, F_SETLK);
+ return tdb_lock_list(tdb, list, ltype, TDB_LOCK_NOWAIT);
}
-/* unlock the database: returns void because it's too late for errors. */
- /* changed to return int it may be interesting to know there
- has been an error --simo */
-int tdb_unlock(struct tdb_context *tdb, int list, int ltype)
+int tdb_nest_unlock(struct tdb_context *tdb, uint32_t offset, int ltype,
+ bool mark_lock)
{
int ret = -1;
- int i;
- struct tdb_lock_type *lck = NULL;
- bool mark_lock = ((ltype & TDB_MARK_LOCK) == TDB_MARK_LOCK);
-
- ltype &= ~TDB_MARK_LOCK;
-
- /* a global lock allows us to avoid per chain locks */
- if (tdb->global_lock.count &&
- (ltype == tdb->global_lock.ltype || ltype == F_RDLCK)) {
- return 0;
- }
-
- if (tdb->global_lock.count) {
- return TDB_ERRCODE(TDB_ERR_LOCK, -1);
- }
+ struct tdb_lock_type *lck;
if (tdb->flags & TDB_NOLOCK)
return 0;
/* Sanity checks */
- if (list < -1 || list >= (int)tdb->header.hash_size) {
- TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_unlock: list %d invalid (%d)\n", list, tdb->header.hash_size));
+ if (offset >= lock_offset(tdb->header.hash_size)) {
+ TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_unlock: offset %u invalid (%d)\n", offset, tdb->header.hash_size));
return ret;
}
- for (i=0; i<tdb->num_lockrecs; i++) {
- if (tdb->lockrecs[i].list == list) {
- lck = &tdb->lockrecs[i];
- break;
- }
- }
-
+ lck = find_nestlock(tdb, offset);
if ((lck == NULL) || (lck->count == 0)) {
TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_unlock: count is 0\n"));
return -1;
if (mark_lock) {
ret = 0;
} else {
- ret = tdb->methods->tdb_brlock(tdb, FREELIST_TOP+4*list, F_UNLCK,
- F_SETLKW, 0, 1);
+ ret = tdb_brunlock(tdb, ltype, offset, 1);
}
- tdb->num_locks--;
/*
* Shrink the array by overwriting the element just unlocked with the
* last array element.
*/
-
- if (tdb->num_lockrecs > 1) {
- *lck = tdb->lockrecs[tdb->num_lockrecs-1];
- }
- tdb->num_lockrecs -= 1;
+ *lck = tdb->lockrecs[--tdb->num_lockrecs];
/*
* We don't bother with realloc when the array shrinks, but if we have
return ret;
}
-/*
- get the transaction lock
- */
-int tdb_transaction_lock(struct tdb_context *tdb, int ltype)
+int tdb_unlock(struct tdb_context *tdb, int list, int ltype)
{
- if (tdb->global_lock.count) {
- return 0;
- }
- if (tdb->have_transaction_lock) {
- tdb->have_transaction_lock++;
+ /* a global 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->methods->tdb_brlock(tdb, TRANSACTION_LOCK, ltype,
- F_SETLKW, 0, 1) == -1) {
- TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_transaction_lock: failed to get transaction lock\n"));
+
+ if (tdb->allrecord_lock.count) {
tdb->ecode = TDB_ERR_LOCK;
return -1;
}
- tdb->have_transaction_lock++;
- return 0;
+
+ return tdb_nest_unlock(tdb, lock_offset(list), ltype, false);
+}
+
+/*
+ get the transaction lock
+ */
+int tdb_transaction_lock(struct tdb_context *tdb, int ltype)
+{
+ return tdb_nest_lock(tdb, TRANSACTION_LOCK, ltype, TDB_LOCK_WAIT);
}
/*
release the transaction lock
*/
-int tdb_transaction_unlock(struct tdb_context *tdb)
+int tdb_transaction_unlock(struct tdb_context *tdb, int ltype)
{
- if (tdb->global_lock.count) {
- return 0;
+ return tdb_nest_unlock(tdb, TRANSACTION_LOCK, ltype, false);
+}
+
+/* Returns 0 if all done, -1 if error, 1 if ok. */
+static int tdb_allrecord_check(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) {
+ tdb->ecode = TDB_ERR_LOCK;
+ return -1;
}
- if (--tdb->have_transaction_lock) {
+
+ if (tdb->allrecord_lock.count && tdb->allrecord_lock.ltype == ltype) {
+ tdb->allrecord_lock.count++;
return 0;
}
- return tdb->methods->tdb_brlock(tdb, TRANSACTION_LOCK, F_UNLCK, F_SETLKW, 0, 1);
-}
+ if (tdb->allrecord_lock.count) {
+ /* a global lock of a different type exists */
+ tdb->ecode = TDB_ERR_LOCK;
+ return -1;
+ }
+ if (tdb_have_extra_locks(tdb)) {
+ /* can't combine global and chain locks */
+ tdb->ecode = TDB_ERR_LOCK;
+ return -1;
+ }
+ if (upgradable && ltype != F_RDLCK) {
+ /* tdb error: you can't upgrade a write lock! */
+ tdb->ecode = TDB_ERR_LOCK;
+ return -1;
+ }
+ return 1;
+}
-/* lock/unlock entire database */
-static int _tdb_lockall(struct tdb_context *tdb, int ltype, int op)
+/* We only need to lock individual bytes, but Linux merges consecutive locks
+ * so we lock in contiguous ranges. */
+static int tdb_chainlock_gradual(struct tdb_context *tdb,
+ int ltype, enum tdb_lock_flags flags,
+ size_t off, size_t len)
{
- bool mark_lock = ((ltype & TDB_MARK_LOCK) == TDB_MARK_LOCK);
-
- ltype &= ~TDB_MARK_LOCK;
+ int ret;
+ enum tdb_lock_flags nb_flags = (flags & ~TDB_LOCK_WAIT);
- /* There are no locks on read-only dbs */
- if (tdb->read_only || tdb->traverse_read)
- return TDB_ERRCODE(TDB_ERR_LOCK, -1);
+ if (len <= 4) {
+ /* Single record. Just do blocking lock. */
+ return tdb_brlock(tdb, ltype, off, len, flags);
+ }
- if (tdb->global_lock.count && tdb->global_lock.ltype == ltype) {
- tdb->global_lock.count++;
+ /* First we try non-blocking. */
+ ret = tdb_brlock(tdb, ltype, off, len, nb_flags);
+ if (ret == 0) {
return 0;
}
- if (tdb->global_lock.count) {
- /* a global lock of a different type exists */
- return TDB_ERRCODE(TDB_ERR_LOCK, -1);
+ /* Try locking first half, then second. */
+ ret = tdb_chainlock_gradual(tdb, ltype, flags, off, len / 2);
+ if (ret == -1)
+ return -1;
+
+ ret = tdb_chainlock_gradual(tdb, ltype, flags,
+ off + len / 2, len - len / 2);
+ if (ret == -1) {
+ tdb_brunlock(tdb, ltype, off, len / 2);
+ return -1;
}
-
- if (tdb->num_locks != 0) {
- /* can't combine global and chain locks */
- return TDB_ERRCODE(TDB_ERR_LOCK, -1);
+ return 0;
+}
+
+/* lock/unlock entire database. It can only be upgradable if you have some
+ * other way of guaranteeing exclusivity (ie. transaction write lock).
+ * We do the locking gradually to avoid being starved by smaller locks. */
+int tdb_allrecord_lock(struct tdb_context *tdb, int ltype,
+ enum tdb_lock_flags flags, bool upgradable)
+{
+ switch (tdb_allrecord_check(tdb, ltype, flags, upgradable)) {
+ case -1:
+ return -1;
+ case 0:
+ return 0;
}
- if (!mark_lock &&
- tdb->methods->tdb_brlock(tdb, FREELIST_TOP, ltype, op,
- 0, 4*tdb->header.hash_size)) {
- if (op == F_SETLKW) {
- TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_lockall failed (%s)\n", strerror(errno)));
- }
+ /* We cover two kinds of locks:
+ * 1) Normal chain locks. Taken for almost all operations.
+ * 3) Individual records locks. Taken after normal or free
+ * chain locks.
+ *
+ * It is (1) which cause the starvation problem, so we're only
+ * gradual for that. */
+ if (tdb_chainlock_gradual(tdb, ltype, flags, FREELIST_TOP,
+ tdb->header.hash_size * 4) == -1) {
+ return -1;
+ }
+
+ /* Grab individual record locks. */
+ if (tdb_brlock(tdb, ltype, lock_offset(tdb->header.hash_size), 0,
+ flags) == -1) {
+ tdb_brunlock(tdb, ltype, FREELIST_TOP,
+ tdb->header.hash_size * 4);
return -1;
}
- tdb->global_lock.count = 1;
- tdb->global_lock.ltype = ltype;
+ tdb->allrecord_lock.count = 1;
+ /* 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)
+int tdb_allrecord_unlock(struct tdb_context *tdb, int ltype, bool mark_lock)
{
- bool mark_lock = ((ltype & TDB_MARK_LOCK) == TDB_MARK_LOCK);
-
- ltype &= ~TDB_MARK_LOCK;
-
/* There are no locks on read-only dbs */
if (tdb->read_only || tdb->traverse_read) {
- return TDB_ERRCODE(TDB_ERR_LOCK, -1);
+ tdb->ecode = TDB_ERR_LOCK;
+ return -1;
}
- if (tdb->global_lock.ltype != ltype || tdb->global_lock.count == 0) {
- return TDB_ERRCODE(TDB_ERR_LOCK, -1);
+ if (tdb->allrecord_lock.count == 0) {
+ tdb->ecode = TDB_ERR_LOCK;
+ return -1;
}
- if (tdb->global_lock.count > 1) {
- tdb->global_lock.count--;
+ /* 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;
+ }
+
+ if (tdb->allrecord_lock.count > 1) {
+ tdb->allrecord_lock.count--;
return 0;
}
- if (!mark_lock &&
- tdb->methods->tdb_brlock(tdb, FREELIST_TOP, F_UNLCK, F_SETLKW,
- 0, 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;
}
- tdb->global_lock.count = 0;
- tdb->global_lock.ltype = 0;
+ tdb->allrecord_lock.count = 0;
+ tdb->allrecord_lock.ltype = 0;
return 0;
}
int tdb_lockall(struct tdb_context *tdb)
{
tdb_trace(tdb, "tdb_lockall");
- return _tdb_lockall(tdb, F_WRLCK, F_SETLKW);
+ 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_MARK_LOCK, F_SETLKW);
+ 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 | TDB_MARK_LOCK);
+ 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, F_SETLK);
+ 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);
+ 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, F_SETLKW);
+ 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, F_SETLK);
+ 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);
+ return tdb_allrecord_unlock(tdb, F_RDLCK, false);
}
/* lock/unlock one hash chain. This is meant to be used to reduce
/* mark a chain as locked without actually locking it. Warning! use with great caution! */
int tdb_chainlock_mark(struct tdb_context *tdb, TDB_DATA key)
{
- int ret = tdb_lock(tdb, BUCKET(tdb->hash_fn(&key)), F_WRLCK | TDB_MARK_LOCK);
+ int ret = tdb_nest_lock(tdb, lock_offset(BUCKET(tdb->hash_fn(&key))),
+ F_WRLCK, TDB_LOCK_MARK_ONLY);
tdb_trace_1rec(tdb, "tdb_chainlock_mark", key);
return ret;
}
int tdb_chainlock_unmark(struct tdb_context *tdb, TDB_DATA key)
{
tdb_trace_1rec(tdb, "tdb_chainlock_unmark", key);
- return tdb_unlock(tdb, BUCKET(tdb->hash_fn(&key)), F_WRLCK | TDB_MARK_LOCK);
+ return tdb_nest_unlock(tdb, lock_offset(BUCKET(tdb->hash_fn(&key))),
+ F_WRLCK, true);
}
int tdb_chainunlock(struct tdb_context *tdb, TDB_DATA key)
return tdb_unlock(tdb, BUCKET(tdb->hash_fn(&key)), F_RDLCK);
}
+
+
/* record lock stops delete underneath */
int tdb_lock_record(struct tdb_context *tdb, tdb_off_t off)
{
- if (tdb->global_lock.count) {
+ if (tdb->allrecord_lock.count) {
return 0;
}
- return off ? tdb->methods->tdb_brlock(tdb, off, F_RDLCK, F_SETLKW, 0, 1) : 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->tdb_brlock(tdb, off, F_WRLCK, F_SETLK, 1, 1);
+ 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);
}
-/*
- Note this is meant to be F_SETLK, *not* F_SETLKW, as it's not
- an error to fail to get the lock here.
-*/
int tdb_write_unlock_record(struct tdb_context *tdb, tdb_off_t off)
{
- return tdb->methods->tdb_brlock(tdb, off, F_UNLCK, F_SETLK, 0, 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 */
struct tdb_traverse_lock *i;
uint32_t count = 0;
- if (tdb->global_lock.count) {
+ if (tdb->allrecord_lock.count) {
return 0;
}
for (i = &tdb->travlocks; i; i = i->next)
if (i->off == off)
count++;
- return (count == 1 ? tdb->methods->tdb_brlock(tdb, off, F_UNLCK, F_SETLKW, 0, 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;
+
+ /* A transaction holds the lock for all records. */
+ if (!tdb->transaction && tdb->allrecord_lock.count) {
+ return true;
+ }
+
+ /* We always hold the active lock if CLEAR_IF_FIRST. */
+ if (find_nestlock(tdb, ACTIVE_LOCK)) {
+ extra--;
+ }
+
+ /* In a transaction, we expect to hold the transaction lock */
+ if (tdb->transaction && find_nestlock(tdb, TRANSACTION_LOCK)) {
+ extra--;
+ }
+
+ return extra;
+}
+
+/* The transaction code uses this to remove all locks. Note that this
+ may include OPEN_LOCK. */
+void tdb_release_extra_locks(struct tdb_context *tdb)
+{
+ unsigned int i, extra = 0;
+
+ if (tdb->allrecord_lock.count != 0) {
+ tdb_brunlock(tdb, tdb->allrecord_lock.ltype, FREELIST_TOP, 0);
+ tdb->allrecord_lock.count = 0;
+ }
+
+ for (i=0;i<tdb->num_lockrecs;i++) {
+ struct tdb_lock_type *lck = &tdb->lockrecs[i];
+
+ /* Don't release transaction or active locks! */
+ if (tdb->transaction && lck->off == TRANSACTION_LOCK) {
+ tdb->lockrecs[extra++] = *lck;
+ } else if (lck->off == ACTIVE_LOCK) {
+ tdb->lockrecs[extra++] = *lck;
+ } else {
+ tdb_brunlock(tdb, lck->ltype, lck->off, 1);
+ }
+ }
+ tdb->num_lockrecs = extra;
+ if (tdb->num_lockrecs == 0) {
+ SAFE_FREE(tdb->lockrecs);
+ }
}
projects / ccan / blobdiff