#include <assert.h>
#include <ccan/build_assert/build_assert.h>
-static int fcntl_lock(struct tdb_context *tdb,
- int rw, off_t off, off_t len, bool waitflag)
+/* If we were threaded, we could wait for unlock, but we're not, so fail. */
+static enum TDB_ERROR owner_conflict(struct tdb_context *tdb, const char *call)
{
- struct flock fl;
+ return tdb_logerr(tdb, TDB_ERR_LOCK, TDB_LOG_USE_ERROR,
+ "%s: lock owned by another tdb in this process.",
+ call);
+}
+
+/* If we fork, we no longer really own locks. */
+static bool check_lock_pid(struct tdb_context *tdb,
+ const char *call, bool log)
+{
+ /* No locks? No problem! */
+ if (tdb->file->allrecord_lock.count == 0
+ && tdb->file->num_lockrecs == 0) {
+ return true;
+ }
- fl.l_type = rw;
- fl.l_whence = SEEK_SET;
- fl.l_start = off;
- fl.l_len = len;
- fl.l_pid = 0;
+ /* No fork? No problem! */
+ if (tdb->file->locker == getpid()) {
+ return true;
+ }
- add_stat(tdb, lock_lowlevel, 1);
- if (waitflag)
- return fcntl(tdb->file->fd, F_SETLKW, &fl);
- else {
- add_stat(tdb, lock_nonblock, 1);
- return fcntl(tdb->file->fd, F_SETLK, &fl);
+ if (log) {
+ tdb_logerr(tdb, TDB_ERR_LOCK, TDB_LOG_USE_ERROR,
+ "%s: fork() detected after lock acquisition!"
+ " (%u vs %u)", call, tdb->file->locker, getpid());
}
+ return false;
+}
+
+int tdb_fcntl_lock(int fd, int rw, off_t off, off_t len, bool waitflag,
+ void *unused)
+{
+ struct flock fl;
+ int ret;
+
+ do {
+ fl.l_type = rw;
+ fl.l_whence = SEEK_SET;
+ fl.l_start = off;
+ fl.l_len = len;
+
+ if (waitflag)
+ ret = fcntl(fd, F_SETLKW, &fl);
+ else
+ ret = fcntl(fd, F_SETLK, &fl);
+ } while (ret != 0 && errno == EINTR);
+ return ret;
}
-static int fcntl_unlock(struct tdb_context *tdb, int rw, off_t off, off_t len)
+int tdb_fcntl_unlock(int fd, int rw, off_t off, off_t len, void *unused)
{
struct flock fl;
+ int ret;
+
+ do {
+ fl.l_type = F_UNLCK;
+ fl.l_whence = SEEK_SET;
+ fl.l_start = off;
+ fl.l_len = len;
+
+ ret = fcntl(fd, F_SETLKW, &fl);
+ } while (ret != 0 && errno == EINTR);
+ return ret;
+}
+
+static int lock(struct tdb_context *tdb,
+ int rw, off_t off, off_t len, bool waitflag)
+{
+ int ret;
+ if (tdb->file->allrecord_lock.count == 0
+ && tdb->file->num_lockrecs == 0) {
+ tdb->file->locker = getpid();
+ }
+
+ tdb->stats.lock_lowlevel++;
+ ret = tdb->lock_fn(tdb->file->fd, rw, off, len, waitflag,
+ tdb->lock_data);
+ if (!waitflag) {
+ tdb->stats.lock_nonblock++;
+ if (ret != 0)
+ tdb->stats.lock_nonblock_fail++;
+ }
+ return ret;
+}
+
+static int unlock(struct tdb_context *tdb, int rw, off_t off, off_t len)
+{
#if 0 /* Check they matched up locks and unlocks correctly. */
char line[80];
FILE *locks;
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->file->fd, F_SETLKW, &fl);
+ return tdb->unlock_fn(tdb->file->fd, rw, off, len, tdb->lock_data);
}
/* a byte range locking function - return 0 on success
note that a len of zero means lock to end of file
*/
-static enum TDB_ERROR tdb_brlock(struct tdb_context *tdb,
- int rw_type, tdb_off_t offset, tdb_off_t len,
- enum tdb_lock_flags flags)
+enum TDB_ERROR tdb_brlock(struct tdb_context *tdb,
+ int rw_type, tdb_off_t offset, tdb_off_t len,
+ enum tdb_lock_flags flags)
{
int ret;
return TDB_SUCCESS;
}
- if (rw_type == F_WRLCK && tdb->read_only) {
+ if (rw_type == F_WRLCK && (tdb->flags & TDB_RDONLY)) {
return tdb_logerr(tdb, TDB_ERR_RDONLY, TDB_LOG_USE_ERROR,
"Write lock attempted on read-only database");
}
(long long)(offset + len));
}
- do {
- ret = fcntl_lock(tdb, rw_type, offset, len,
- flags & TDB_LOCK_WAIT);
- } while (ret == -1 && errno == EINTR);
-
- if (ret == -1) {
+ ret = lock(tdb, rw_type, offset, len, flags & TDB_LOCK_WAIT);
+ if (ret != 0) {
/* Generic lock error. errno set by fcntl.
* EAGAIN is an expected return from non-blocking
* locks. */
- if (!(flags & TDB_LOCK_PROBE) && errno != EAGAIN) {
+ if (!(flags & TDB_LOCK_PROBE)
+ && (errno != EAGAIN && errno != EINTR)) {
tdb_logerr(tdb, TDB_ERR_LOCK, TDB_LOG_ERROR,
"tdb_brlock failed (fd=%d) at"
" offset %zu rw_type=%d flags=%d len=%zu:"
return TDB_SUCCESS;
}
-static enum TDB_ERROR tdb_brunlock(struct tdb_context *tdb,
- int rw_type, tdb_off_t offset, size_t len)
+enum TDB_ERROR tdb_brunlock(struct tdb_context *tdb,
+ int rw_type, tdb_off_t offset, size_t len)
{
- int ret;
-
if (tdb->flags & TDB_NOLOCK) {
return TDB_SUCCESS;
}
- do {
- ret = fcntl_unlock(tdb, rw_type, offset, len);
- } while (ret == -1 && errno == EINTR);
+ if (!check_lock_pid(tdb, "tdb_brunlock", true))
+ return TDB_ERR_LOCK;
- if (ret == -1) {
+ if (unlock(tdb, rw_type, offset, len) == -1) {
return tdb_logerr(tdb, TDB_ERR_LOCK, TDB_LOG_ERROR,
"tdb_brunlock failed (fd=%d) at offset %zu"
- " rw_type=%d len=%zu",
+ " rw_type=%d len=%zu: %s",
tdb->file->fd, (size_t)offset, rw_type,
- (size_t)len);
+ (size_t)len, strerror(errno));
}
return TDB_SUCCESS;
}
deadlock detection and claim a deadlock when progress can be
made. For those OSes we may loop for a while.
*/
-enum TDB_ERROR tdb_allrecord_upgrade(struct tdb_context *tdb)
+enum TDB_ERROR tdb_allrecord_upgrade(struct tdb_context *tdb, off_t start)
{
int count = 1000;
+ if (!check_lock_pid(tdb, "tdb_transaction_prepare_commit", true))
+ return TDB_ERR_LOCK;
+
if (tdb->file->allrecord_lock.count != 1) {
return tdb_logerr(tdb, TDB_ERR_LOCK, TDB_LOG_ERROR,
"tdb_allrecord_upgrade failed:"
" already upgraded?");
}
+ if (tdb->file->allrecord_lock.owner != tdb) {
+ return owner_conflict(tdb, "tdb_allrecord_upgrade");
+ }
+
while (count--) {
struct timeval tv;
- if (tdb_brlock(tdb, F_WRLCK,
- TDB_HASH_LOCK_START, 0,
+ if (tdb_brlock(tdb, F_WRLCK, start, 0,
TDB_LOCK_WAIT|TDB_LOCK_PROBE) == TDB_SUCCESS) {
tdb->file->allrecord_lock.ltype = F_WRLCK;
tdb->file->allrecord_lock.off = 0;
tv.tv_usec = 1;
select(0, NULL, NULL, NULL, &tv);
}
- return tdb_logerr(tdb, TDB_ERR_LOCK, TDB_LOG_ERROR,
- "tdb_allrecord_upgrade failed");
+
+ if (errno != EAGAIN && errno != EINTR)
+ tdb_logerr(tdb, TDB_ERR_LOCK, TDB_LOG_ERROR,
+ "tdb_allrecord_upgrade failed");
+ return TDB_ERR_LOCK;
}
-static struct tdb_lock_type *find_nestlock(struct tdb_context *tdb,
- tdb_off_t offset)
+static struct tdb_lock *find_nestlock(struct tdb_context *tdb, tdb_off_t offset,
+ const struct tdb_context *owner)
{
unsigned int i;
for (i=0; i<tdb->file->num_lockrecs; i++) {
if (tdb->file->lockrecs[i].off == offset) {
+ if (owner && tdb->file->lockrecs[i].owner != owner)
+ return NULL;
return &tdb->file->lockrecs[i];
}
}
{
enum TDB_ERROR ecode;
+ if (!check_lock_pid(tdb, "tdb_transaction_prepare_commit", true))
+ return TDB_ERR_LOCK;
+
ecode = tdb_allrecord_lock(tdb, F_WRLCK, TDB_LOCK_WAIT|TDB_LOCK_NOCHECK,
false);
if (ecode != TDB_SUCCESS) {
return ecode;
}
- ecode = tdb_lock_open(tdb, TDB_LOCK_WAIT|TDB_LOCK_NOCHECK);
+ ecode = tdb_lock_open(tdb, F_WRLCK, TDB_LOCK_WAIT|TDB_LOCK_NOCHECK);
if (ecode != TDB_SUCCESS) {
tdb_allrecord_unlock(tdb, F_WRLCK);
return ecode;
}
ecode = tdb_transaction_recover(tdb);
- tdb_unlock_open(tdb);
+ tdb_unlock_open(tdb, F_WRLCK);
tdb_allrecord_unlock(tdb, F_WRLCK);
return ecode;
}
/* lock an offset in the database. */
-static enum TDB_ERROR tdb_nest_lock(struct tdb_context *tdb,
- tdb_off_t offset, int ltype,
- enum tdb_lock_flags flags)
+enum TDB_ERROR tdb_nest_lock(struct tdb_context *tdb,
+ tdb_off_t offset, int ltype,
+ enum tdb_lock_flags flags)
{
- struct tdb_lock_type *new_lck;
+ struct tdb_lock *new_lck;
enum TDB_ERROR ecode;
- if (offset > (TDB_HASH_LOCK_START + TDB_HASH_LOCK_RANGE
- + tdb->file->map_size / 8)) {
+ if (!(tdb->flags & TDB_VERSION1)
+ && offset > (TDB_HASH_LOCK_START + TDB_HASH_LOCK_RANGE
+ + tdb->file->map_size / 8)) {
return tdb_logerr(tdb, TDB_ERR_LOCK, TDB_LOG_ERROR,
"tdb_nest_lock: invalid offset %zu ltype=%d",
(size_t)offset, ltype);
if (tdb->flags & TDB_NOLOCK)
return TDB_SUCCESS;
- add_stat(tdb, locks, 1);
+ if (!check_lock_pid(tdb, "tdb_nest_lock", true)) {
+ return TDB_ERR_LOCK;
+ }
+
+ tdb->stats.locks++;
- new_lck = find_nestlock(tdb, offset);
+ new_lck = find_nestlock(tdb, offset, NULL);
if (new_lck) {
+ if (new_lck->owner != tdb) {
+ return owner_conflict(tdb, "tdb_nest_lock");
+ }
+
if (new_lck->ltype == F_RDLCK && ltype == F_WRLCK) {
return tdb_logerr(tdb, TDB_ERR_LOCK, TDB_LOG_ERROR,
"tdb_nest_lock:"
return TDB_SUCCESS;
}
+#if 0
if (tdb->file->num_lockrecs
&& offset >= TDB_HASH_LOCK_START
&& offset < TDB_HASH_LOCK_START + TDB_HASH_LOCK_RANGE) {
return tdb_logerr(tdb, TDB_ERR_LOCK, TDB_LOG_ERROR,
"tdb_nest_lock: already have a hash lock?");
}
+#endif
- new_lck = (struct tdb_lock_type *)realloc(
+ new_lck = (struct tdb_lock *)realloc(
tdb->file->lockrecs,
sizeof(*tdb->file->lockrecs) * (tdb->file->num_lockrecs+1));
if (new_lck == NULL) {
}
}
+ tdb->file->lockrecs[tdb->file->num_lockrecs].owner = tdb;
tdb->file->lockrecs[tdb->file->num_lockrecs].off = offset;
tdb->file->lockrecs[tdb->file->num_lockrecs].count = 1;
tdb->file->lockrecs[tdb->file->num_lockrecs].ltype = ltype;
return TDB_SUCCESS;
}
-static enum TDB_ERROR tdb_nest_unlock(struct tdb_context *tdb,
- tdb_off_t off, int ltype)
+enum TDB_ERROR tdb_nest_unlock(struct tdb_context *tdb,
+ tdb_off_t off, int ltype)
{
- struct tdb_lock_type *lck;
+ struct tdb_lock *lck;
enum TDB_ERROR ecode;
if (tdb->flags & TDB_NOLOCK)
return TDB_SUCCESS;
- lck = find_nestlock(tdb, off);
+ lck = find_nestlock(tdb, off, tdb);
if ((lck == NULL) || (lck->count == 0)) {
return tdb_logerr(tdb, TDB_ERR_LOCK, TDB_LOG_ERROR,
"tdb_nest_unlock: no lock for %zu",
/* We only need to lock individual bytes, but Linux merges consecutive locks
* so we lock in contiguous ranges. */
-static enum TDB_ERROR tdb_lock_gradual(struct tdb_context *tdb,
- int ltype, enum tdb_lock_flags flags,
- tdb_off_t off, tdb_off_t len)
+enum TDB_ERROR tdb_lock_gradual(struct tdb_context *tdb,
+ int ltype, enum tdb_lock_flags flags,
+ tdb_off_t off, tdb_off_t len)
{
enum TDB_ERROR ecode;
enum tdb_lock_flags nb_flags = (flags & ~TDB_LOCK_WAIT);
}
/* First we try non-blocking. */
- if (tdb_brlock(tdb, ltype, off, len, nb_flags) == TDB_SUCCESS) {
- return TDB_SUCCESS;
+ ecode = tdb_brlock(tdb, ltype, off, len, nb_flags);
+ if (ecode != TDB_ERR_LOCK) {
+ return ecode;
}
/* Try locking first half, then second. */
enum TDB_ERROR ecode;
tdb_bool_err berr;
- if (tdb->file->allrecord_lock.count
- && (ltype == F_RDLCK
- || tdb->file->allrecord_lock.ltype == F_WRLCK)) {
- tdb->file->allrecord_lock.count++;
+ if (tdb->flags & TDB_NOLOCK)
return TDB_SUCCESS;
+
+ if (!check_lock_pid(tdb, "tdb_allrecord_lock", true)) {
+ return TDB_ERR_LOCK;
}
if (tdb->file->allrecord_lock.count) {
+ if (tdb->file->allrecord_lock.owner != tdb) {
+ return owner_conflict(tdb, "tdb_allrecord_lock");
+ }
+
+ if (ltype == F_RDLCK
+ || tdb->file->allrecord_lock.ltype == F_WRLCK) {
+ tdb->file->allrecord_lock.count++;
+ return TDB_SUCCESS;
+ }
+
/* a global lock of a different type exists */
return tdb_logerr(tdb, TDB_ERR_LOCK, TDB_LOG_USE_ERROR,
"tdb_allrecord_lock: already have %s lock",
" can't upgrade a write lock");
}
- add_stat(tdb, locks, 1);
+ tdb->stats.locks++;
again:
/* Lock hashes, gradually. */
ecode = tdb_lock_gradual(tdb, ltype, flags, TDB_HASH_LOCK_START,
TDB_HASH_LOCK_RANGE);
- if (ecode != TDB_SUCCESS) {
- if (!(flags & TDB_LOCK_PROBE)) {
- tdb_logerr(tdb, ecode, TDB_LOG_ERROR,
- "tdb_allrecord_lock hashes failed");
- }
+ if (ecode != TDB_SUCCESS)
return ecode;
- }
/* Lock free tables: there to end of file. */
ecode = tdb_brlock(tdb, ltype,
TDB_HASH_LOCK_START + TDB_HASH_LOCK_RANGE,
0, flags);
if (ecode != TDB_SUCCESS) {
- if (!(flags & TDB_LOCK_PROBE)) {
- tdb_logerr(tdb, ecode, TDB_LOG_ERROR,
- "tdb_allrecord_lock freetables failed");
- }
tdb_brunlock(tdb, ltype, TDB_HASH_LOCK_START,
TDB_HASH_LOCK_RANGE);
return ecode;
}
+ tdb->file->allrecord_lock.owner = tdb;
tdb->file->allrecord_lock.count = 1;
/* If it's upgradable, it's actually exclusive so we can treat
* it as a write lock. */
goto again;
}
-enum TDB_ERROR tdb_lock_open(struct tdb_context *tdb, enum tdb_lock_flags flags)
+enum TDB_ERROR tdb_lock_open(struct tdb_context *tdb,
+ int ltype, enum tdb_lock_flags flags)
{
- return tdb_nest_lock(tdb, TDB_OPEN_LOCK, F_WRLCK, flags);
+ return tdb_nest_lock(tdb, TDB_OPEN_LOCK, ltype, flags);
}
-void tdb_unlock_open(struct tdb_context *tdb)
+void tdb_unlock_open(struct tdb_context *tdb, int ltype)
{
- tdb_nest_unlock(tdb, TDB_OPEN_LOCK, F_WRLCK);
+ tdb_nest_unlock(tdb, TDB_OPEN_LOCK, ltype);
}
bool tdb_has_open_lock(struct tdb_context *tdb)
{
return !(tdb->flags & TDB_NOLOCK)
- && find_nestlock(tdb, TDB_OPEN_LOCK) != NULL;
+ && find_nestlock(tdb, TDB_OPEN_LOCK, tdb) != NULL;
}
enum TDB_ERROR tdb_lock_expand(struct tdb_context *tdb, int ltype)
/* unlock entire db */
void tdb_allrecord_unlock(struct tdb_context *tdb, int ltype)
{
+ if (tdb->flags & TDB_NOLOCK)
+ return;
+
if (tdb->file->allrecord_lock.count == 0) {
tdb_logerr(tdb, TDB_ERR_LOCK, TDB_LOG_USE_ERROR,
"tdb_allrecord_unlock: not locked!");
return;
}
+ if (tdb->file->allrecord_lock.owner != tdb) {
+ tdb_logerr(tdb, TDB_ERR_LOCK, TDB_LOG_USE_ERROR,
+ "tdb_allrecord_unlock: not locked by us!");
+ return;
+ }
+
/* Upgradable locks are marked as write locks. */
if (tdb->file->allrecord_lock.ltype != ltype
&& (!tdb->file->allrecord_lock.off || ltype != F_RDLCK)) {
bool tdb_has_expansion_lock(struct tdb_context *tdb)
{
- return find_nestlock(tdb, TDB_EXPANSION_LOCK) != NULL;
+ return find_nestlock(tdb, TDB_EXPANSION_LOCK, tdb) != NULL;
}
bool tdb_has_hash_locks(struct tdb_context *tdb)
int ltype, enum tdb_lock_flags waitflag)
{
/* FIXME: Do this properly, using hlock_range */
- unsigned lock = TDB_HASH_LOCK_START
+ unsigned l = TDB_HASH_LOCK_START
+ (hash_lock >> (64 - TDB_HASH_LOCK_RANGE_BITS));
/* a allrecord lock allows us to avoid per chain locks */
- if (tdb->file->allrecord_lock.count &&
- (ltype == tdb->file->allrecord_lock.ltype || ltype == F_RDLCK)) {
- return TDB_SUCCESS;
- }
-
if (tdb->file->allrecord_lock.count) {
+ if (!check_lock_pid(tdb, "tdb_lock_hashes", true))
+ return TDB_ERR_LOCK;
+
+ if (tdb->file->allrecord_lock.owner != tdb)
+ return owner_conflict(tdb, "tdb_lock_hashes");
+ if (ltype == tdb->file->allrecord_lock.ltype
+ || ltype == F_RDLCK) {
+ return TDB_SUCCESS;
+ }
+
return tdb_logerr(tdb, TDB_ERR_LOCK, TDB_LOG_USE_ERROR,
"tdb_lock_hashes:"
" already have %s allrecordlock",
" already have expansion lock");
}
- return tdb_nest_lock(tdb, lock, ltype, waitflag);
+ return tdb_nest_lock(tdb, l, ltype, waitflag);
}
enum TDB_ERROR tdb_unlock_hashes(struct tdb_context *tdb,
tdb_off_t hash_lock,
tdb_len_t hash_range, int ltype)
{
- unsigned lock = TDB_HASH_LOCK_START
+ unsigned l = TDB_HASH_LOCK_START
+ (hash_lock >> (64 - TDB_HASH_LOCK_RANGE_BITS));
if (tdb->flags & TDB_NOLOCK)
return TDB_SUCCESS;
}
- return tdb_nest_unlock(tdb, lock, ltype);
+ return tdb_nest_unlock(tdb, l, ltype);
}
/* Hash locks use TDB_HASH_LOCK_START + the next 30 bits.
/* a allrecord lock allows us to avoid per chain locks */
if (tdb->file->allrecord_lock.count) {
+ if (!check_lock_pid(tdb, "tdb_lock_free_bucket", true))
+ return TDB_ERR_LOCK;
+
if (tdb->file->allrecord_lock.ltype == F_WRLCK)
return 0;
return tdb_logerr(tdb, TDB_ERR_LOCK, TDB_LOG_ERROR,
tdb_nest_unlock(tdb, free_lock_off(b_off), F_WRLCK);
}
+
+enum TDB_ERROR tdb_lockall(struct tdb_context *tdb)
+{
+ return tdb_allrecord_lock(tdb, F_WRLCK, TDB_LOCK_WAIT, false);
+}
+
+void tdb_unlockall(struct tdb_context *tdb)
+{
+ tdb_allrecord_unlock(tdb, F_WRLCK);
+}
+
+enum TDB_ERROR tdb_lockall_read(struct tdb_context *tdb)
+{
+ return tdb_allrecord_lock(tdb, F_RDLCK, TDB_LOCK_WAIT, false);
+}
+
+void tdb_unlockall_read(struct tdb_context *tdb)
+{
+ tdb_allrecord_unlock(tdb, F_RDLCK);
+}
+
+void tdb_lock_cleanup(struct tdb_context *tdb)
+{
+ unsigned int i;
+
+ /* We don't want to warn: they're allowed to close tdb after fork. */
+ if (!check_lock_pid(tdb, "tdb_close", false))
+ return;
+
+ while (tdb->file->allrecord_lock.count
+ && tdb->file->allrecord_lock.owner == tdb) {
+ tdb_allrecord_unlock(tdb, tdb->file->allrecord_lock.ltype);
+ }
+
+ for (i=0; i<tdb->file->num_lockrecs; i++) {
+ if (tdb->file->lockrecs[i].owner == tdb) {
+ tdb_nest_unlock(tdb,
+ tdb->file->lockrecs[i].off,
+ tdb->file->lockrecs[i].ltype);
+ i--;
+ }
+ }
+}
projects / ccan / blobdiff