- don't allow any locks to be held when a transaction starts,
otherwise we can end up with deadlock (plus lack of lock nesting
- in posix locks would mean the lock is lost)
+ in POSIX locks would mean the lock is lost)
- if the caller gains a lock during the transaction but doesn't
release it then fail the commit
- allow for nested calls to tdb_transaction_start(), re-using the
- existing transaction record. If the inner transaction is cancelled
+ existing transaction record. If the inner transaction is canceled
then a subsequent commit will fail
- keep a mirrored copy of the tdb hash chain heads to allow for the
- allow callers to mix transaction and non-transaction use of tdb,
although once a transaction is started then an exclusive lock is
- gained until the transaction is committed or cancelled
+ gained until the transaction is committed or canceled
- the commit stategy involves first saving away all modified data
into a linearised buffer in the transaction recovery area, then
/*
- write while in a transaction - this varient never expands the transaction blocks, it only
+ write while in a transaction - this variant never expands the transaction blocks, it only
updates existing blocks. This means it cannot change the recovery size
*/
static void transaction_write_existing(struct tdb_context *tdb, tdb_off_t off,
start a tdb transaction. No token is returned, as only a single
transaction is allowed to be pending per tdb_context
*/
-int tdb_transaction_start(struct tdb_context *tdb)
+enum TDB_ERROR tdb_transaction_start(struct tdb_context *tdb)
{
enum TDB_ERROR ecode;
/* some sanity checks */
if (tdb->read_only || (tdb->flags & TDB_INTERNAL)) {
- tdb_logerr(tdb, TDB_ERR_EINVAL, TDB_LOG_USE_ERROR,
- "tdb_transaction_start: cannot start a transaction"
- " on a read-only or internal db");
- return -1;
+ return tdb_logerr(tdb, TDB_ERR_EINVAL, TDB_LOG_USE_ERROR,
+ "tdb_transaction_start: cannot start a"
+ " transaction on a read-only or internal db");
}
/* cope with nested tdb_transaction_start() calls */
if (tdb->transaction != NULL) {
- tdb_logerr(tdb, TDB_ERR_IO, TDB_LOG_USE_ERROR,
- "tdb_transaction_start:"
- " already inside transaction");
- return -1;
+ return tdb_logerr(tdb, TDB_ERR_IO, TDB_LOG_USE_ERROR,
+ "tdb_transaction_start:"
+ " already inside transaction");
}
if (tdb_has_hash_locks(tdb)) {
/* the caller must not have any locks when starting a
transaction as otherwise we'll be screwed by lack
- of nested locks in posix */
- tdb_logerr(tdb, TDB_ERR_LOCK, TDB_LOG_USE_ERROR,
- "tdb_transaction_start: cannot start a transaction"
- " with locks held");
- return -1;
+ of nested locks in POSIX */
+ return tdb_logerr(tdb, TDB_ERR_LOCK, TDB_LOG_USE_ERROR,
+ "tdb_transaction_start: cannot start a"
+ " transaction with locks held");
}
tdb->transaction = (struct tdb_transaction *)
calloc(sizeof(struct tdb_transaction), 1);
if (tdb->transaction == NULL) {
- tdb_logerr(tdb, TDB_ERR_OOM, TDB_LOG_ERROR,
- "tdb_transaction_start: cannot allocate");
- return -1;
+ return tdb_logerr(tdb, TDB_ERR_OOM, TDB_LOG_ERROR,
+ "tdb_transaction_start: cannot allocate");
}
/* get the transaction write lock. This is a blocking lock. As
make this async, which we will probably do in the future */
ecode = tdb_transaction_lock(tdb, F_WRLCK);
if (ecode != TDB_SUCCESS) {
- tdb->ecode = ecode;
SAFE_FREE(tdb->transaction->blocks);
SAFE_FREE(tdb->transaction);
- return -1;
+ return ecode;
}
/* get a read lock over entire file. This is upgraded to a write
lock during the commit */
ecode = tdb_allrecord_lock(tdb, F_RDLCK, TDB_LOCK_WAIT, true);
if (ecode != TDB_SUCCESS) {
- tdb->ecode = ecode;
goto fail_allrecord_lock;
}
transaction specific methods */
tdb->transaction->io_methods = tdb->methods;
tdb->methods = &transaction_methods;
- return 0;
+ return TDB_SUCCESS;
fail_allrecord_lock:
tdb_transaction_unlock(tdb, F_WRLCK);
SAFE_FREE(tdb->transaction->blocks);
SAFE_FREE(tdb->transaction);
- return -1;
+ return ecode;
}
static enum TDB_ERROR transaction_setup_recovery(struct tdb_context *tdb,
tdb_off_t *magic_offset)
{
- tdb_len_t recovery_size;
+ /* Initialized for GCC's 4.4.5 overzealous uninitialized warnings. */
+ tdb_len_t recovery_size = 0;
+ tdb_off_t recovery_offset = 0, recovery_max_size = 0;
unsigned char *data, *p;
const struct tdb_methods *methods = tdb->transaction->io_methods;
struct tdb_recovery_record *rec;
- tdb_off_t recovery_offset, recovery_max_size;
tdb_off_t old_map_size = tdb->transaction->old_map_size;
uint64_t magic, tailer;
int i;
/*
prepare to commit the current transaction
*/
-int tdb_transaction_prepare_commit(struct tdb_context *tdb)
+enum TDB_ERROR tdb_transaction_prepare_commit(struct tdb_context *tdb)
{
- tdb->ecode = _tdb_transaction_prepare_commit(tdb);
- if (tdb->ecode != TDB_SUCCESS)
- return -1;
- return 0;
+ return _tdb_transaction_prepare_commit(tdb);
}
/*
commit the current transaction
*/
-int tdb_transaction_commit(struct tdb_context *tdb)
+enum TDB_ERROR tdb_transaction_commit(struct tdb_context *tdb)
{
const struct tdb_methods *methods;
int i;
enum TDB_ERROR ecode;
if (tdb->transaction == NULL) {
- tdb_logerr(tdb, TDB_ERR_EINVAL, TDB_LOG_USE_ERROR,
- "tdb_transaction_commit: no transaction");
- return -1;
+ return tdb_logerr(tdb, TDB_ERR_EINVAL, TDB_LOG_USE_ERROR,
+ "tdb_transaction_commit: no transaction");
}
tdb_trace(tdb, "tdb_transaction_commit");
if (tdb->transaction->nesting != 0) {
tdb->transaction->nesting--;
- return 0;
+ return TDB_SUCCESS;
}
/* check for a null transaction */
if (tdb->transaction->blocks == NULL) {
_tdb_transaction_cancel(tdb);
- return 0;
+ return TDB_SUCCESS;
}
if (!tdb->transaction->prepared) {
- tdb->ecode = _tdb_transaction_prepare_commit(tdb);
- if (tdb->ecode != TDB_SUCCESS)
- return -1;
+ ecode = _tdb_transaction_prepare_commit(tdb);
+ if (ecode != TDB_SUCCESS)
+ return ecode;
}
methods = tdb->transaction->io_methods;
_tdb_transaction_cancel(tdb);
- return -1;
+ return ecode;
}
SAFE_FREE(tdb->transaction->blocks[i]);
}
/* ensure the new data is on disk */
ecode = transaction_sync(tdb, 0, tdb->map_size);
if (ecode != TDB_SUCCESS) {
- tdb->ecode = ecode;
- return -1;
+ return ecode;
}
/*
transaction locks */
_tdb_transaction_cancel(tdb);
- return 0;
+ return TDB_SUCCESS;
}
projects / ccan / blobdiff