still available, but no transaction recovery area is used and no
fsync/msync calls are made.
- - if TDB_NO_NESTING is passed to flags in tdb open then transaction
- nesting is disabled. tdb_transaction_start() will then implicitely
- cancel any pending transactions and always start a new transaction
- context instead of nesting.
-
+ - if TDB_ALLOW_NESTING is passed to flags in tdb open, or added using
+ tdb_add_flags() transaction nesting is enabled.
+ It resets the TDB_DISALLOW_NESTING flag, as both cannot be used together.
+ The default is that transaction nesting is allowed.
+ Note: this default may change in future versions of tdb.
+
+ Beware. when transactions are nested a transaction successfully
+ completed with tdb_transaction_commit() can be silently unrolled later.
+
+ - if TDB_DISALLOW_NESTING is passed to flags in tdb open, or added using
+ tdb_add_flags() transaction nesting is disabled.
+ It resets the TDB_ALLOW_NESTING flag, as both cannot be used together.
+ An attempt create a nested transaction will fail with TDB_ERR_NESTING.
+ The default is that transaction nesting is allowed.
+ Note: this default may change in future versions of tdb.
*/
but don't create a new transaction */
int nesting;
+ /* set when a prepare has already occurred */
+ bool prepared;
+ tdb_off_t magic_offset;
+
+ /* set when the GLOBAL_LOCK has been taken */
+ bool global_lock_taken;
+
/* old file size before transaction */
tdb_len_t old_map_size;
+
+ /* we should re-pack on commit */
+ bool need_repack;
};
{
uint32_t blk;
+ /* Only a commit is allowed on a prepared transaction */
+ if (tdb->transaction->prepared) {
+ tdb->ecode = TDB_ERR_EINVAL;
+ TDB_LOG((tdb, TDB_DEBUG_FATAL, "transaction_write: transaction already prepared, write not allowed\n"));
+ tdb->transaction->transaction_error = 1;
+ return -1;
+ }
+
/* if the write is to a hash head, then update the transaction
hash heads */
if (len == sizeof(tdb_off_t) && off >= FREELIST_TOP &&
if (len <= tdb->map_size) {
return 0;
}
- return TDB_ERRCODE(TDB_ERR_IO, -1);
+ tdb->ecode = TDB_ERR_IO;
+ return -1;
}
/*
return -1;
}
+ tdb->transaction->need_repack = true;
+
return 0;
}
/*
brlock during a transaction - ignore them
*/
-static int transaction_brlock(struct tdb_context *tdb, tdb_off_t offset,
- int rw_type, int lck_type, int probe, size_t len)
+static int transaction_brlock(struct tdb_context *tdb,
+ int rw_type, tdb_off_t offset, size_t len,
+ enum tdb_lock_flags flags)
+{
+ return 0;
+}
+
+static int transaction_brunlock(struct tdb_context *tdb,
+ int rw_type, tdb_off_t offset, size_t len)
{
return 0;
}
transaction_next_hash_chain,
transaction_oob,
transaction_expand_file,
- transaction_brlock
+ transaction_brlock,
+ transaction_brunlock
};
-int tdb_transaction_cancel_internal(struct tdb_context *tdb)
+/*
+ sync to disk
+*/
+static int transaction_sync(struct tdb_context *tdb, tdb_off_t offset, tdb_len_t length)
+{
+ if (tdb->flags & TDB_NOSYNC) {
+ return 0;
+ }
+
+ if (fsync(tdb->fd) != 0) {
+ tdb->ecode = TDB_ERR_IO;
+ TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_transaction: fsync failed\n"));
+ return -1;
+ }
+#ifdef MS_SYNC
+ if (tdb->map_ptr) {
+ tdb_off_t moffset = offset & ~(tdb->page_size-1);
+ if (msync(moffset + (char *)tdb->map_ptr,
+ length + (offset - moffset), MS_SYNC) != 0) {
+ tdb->ecode = TDB_ERR_IO;
+ TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_transaction: msync failed - %s\n",
+ strerror(errno)));
+ return -1;
+ }
+ }
+#endif
+ return 0;
+}
+
+/* ltype is F_WRLCK after prepare. */
+int _tdb_transaction_cancel(struct tdb_context *tdb, int ltype)
{
- int i;
+ int i, ret = 0;
if (tdb->transaction == NULL) {
TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_transaction_cancel: no transaction\n"));
}
SAFE_FREE(tdb->transaction->blocks);
+ if (tdb->transaction->magic_offset) {
+ const struct tdb_methods *methods = tdb->transaction->io_methods;
+ uint32_t invalid = TDB_RECOVERY_INVALID_MAGIC;
+
+ /* remove the recovery marker */
+ if (methods->tdb_write(tdb, tdb->transaction->magic_offset, &invalid, 4) == -1 ||
+ transaction_sync(tdb, tdb->transaction->magic_offset, 4) == -1) {
+ TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_transaction_cancel: failed to remove recovery magic\n"));
+ ret = -1;
+ }
+ }
+
+ if (tdb->transaction->global_lock_taken) {
+ tdb_brunlock(tdb, F_WRLCK, GLOBAL_LOCK, 1);
+ tdb->transaction->global_lock_taken = false;
+ }
+
/* remove any global lock created during the transaction */
if (tdb->global_lock.count != 0) {
- tdb_brlock(tdb, FREELIST_TOP, F_UNLCK, F_SETLKW, 0, 4*tdb->header.hash_size);
+ tdb_brunlock(tdb, tdb->global_lock.ltype,
+ FREELIST_TOP, 4*tdb->header.hash_size);
tdb->global_lock.count = 0;
}
/* remove any locks created during the transaction */
if (tdb->num_locks != 0) {
for (i=0;i<tdb->num_lockrecs;i++) {
- tdb_brlock(tdb,FREELIST_TOP+4*tdb->lockrecs[i].list,
- F_UNLCK,F_SETLKW, 0, 1);
+ tdb_brunlock(tdb, tdb->lockrecs[i].ltype,
+ FREELIST_TOP+4*tdb->lockrecs[i].list, 1);
}
tdb->num_locks = 0;
tdb->num_lockrecs = 0;
/* restore the normal io methods */
tdb->methods = tdb->transaction->io_methods;
- tdb_brlock(tdb, FREELIST_TOP, F_UNLCK, F_SETLKW, 0, 0);
- tdb_transaction_unlock(tdb);
+ tdb_brunlock(tdb, ltype, FREELIST_TOP, 0);
+ tdb_transaction_unlock(tdb, F_WRLCK);
SAFE_FREE(tdb->transaction->hash_heads);
SAFE_FREE(tdb->transaction);
- return 0;
+ return ret;
}
/*
*/
int tdb_transaction_start(struct tdb_context *tdb)
{
- tdb_trace(tdb, "tdb_transaction_start");
-
/* some sanity checks */
if (tdb->read_only || (tdb->flags & TDB_INTERNAL) || tdb->traverse_read) {
TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_transaction_start: cannot start a transaction on a read-only or internal db\n"));
/* cope with nested tdb_transaction_start() calls */
if (tdb->transaction != NULL) {
- if (!tdb->flags & TDB_NO_NESTING) {
- tdb->transaction->nesting++;
- TDB_LOG((tdb, TDB_DEBUG_TRACE, "tdb_transaction_start: nesting %d\n",
- tdb->transaction->nesting));
- return 0;
- } else {
- tdb_transaction_cancel_internal(tdb);
- TDB_LOG((tdb, TDB_DEBUG_TRACE, "tdb_transaction_start: cancelling previous transaction\n"));
+ if (!(tdb->flags & TDB_ALLOW_NESTING)) {
+ tdb->ecode = TDB_ERR_NESTING;
+ return -1;
}
+ tdb_trace(tdb, "tdb_transaction_start");
+ tdb->transaction->nesting++;
+ TDB_LOG((tdb, TDB_DEBUG_TRACE, "tdb_transaction_start: nesting %d\n",
+ tdb->transaction->nesting));
+ return 0;
}
if (tdb->num_locks != 0 || tdb->global_lock.count) {
/* get a read lock from the freelist to the end of file. This
is upgraded to a write lock during the commit */
- if (tdb_brlock(tdb, FREELIST_TOP, F_RDLCK, F_SETLKW, 0, 0) == -1) {
+ if (tdb_brlock(tdb, F_RDLCK, FREELIST_TOP, 0, TDB_LOCK_WAIT) == -1) {
TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_transaction_start: failed to get hash locks\n"));
tdb->ecode = TDB_ERR_LOCK;
goto fail;
tdb->transaction->io_methods = tdb->methods;
tdb->methods = &transaction_methods;
+ /* Trace at the end, so we get sequence number correct. */
+ tdb_trace(tdb, "tdb_transaction_start");
return 0;
fail:
- tdb_brlock(tdb, FREELIST_TOP, F_UNLCK, F_SETLKW, 0, 0);
- tdb_transaction_unlock(tdb);
+ tdb_brunlock(tdb, F_RDLCK, FREELIST_TOP, 0);
+ tdb_transaction_unlock(tdb, F_WRLCK);
SAFE_FREE(tdb->transaction->blocks);
SAFE_FREE(tdb->transaction->hash_heads);
SAFE_FREE(tdb->transaction);
cancel the current transaction
*/
int tdb_transaction_cancel(struct tdb_context *tdb)
-{
+{
+ int ltype = F_RDLCK;
tdb_trace(tdb, "tdb_transaction_cancel");
- return tdb_transaction_cancel_internal(tdb);
+ if (tdb->transaction && tdb->transaction->prepared)
+ ltype = F_WRLCK;
+ return _tdb_transaction_cancel(tdb, ltype);
}
-/*
- sync to disk
-*/
-static int transaction_sync(struct tdb_context *tdb, tdb_off_t offset, tdb_len_t length)
-{
- if (fsync(tdb->fd) != 0) {
- tdb->ecode = TDB_ERR_IO;
- TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_transaction: fsync failed\n"));
- return -1;
- }
-#ifdef MS_SYNC
- if (tdb->map_ptr) {
- tdb_off_t moffset = offset & ~(tdb->page_size-1);
- if (msync(moffset + (char *)tdb->map_ptr,
- length + (offset - moffset), MS_SYNC) != 0) {
- tdb->ecode = TDB_ERR_IO;
- TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_transaction: msync failed - %s\n",
- strerror(errno)));
- return -1;
- }
- }
-#endif
- return 0;
-}
-
/*
work out how much space the linearised recovery data will consume
tdb_off_t *recovery_offset,
tdb_len_t *recovery_max_size)
{
- struct list_struct rec;
+ struct tdb_record rec;
const struct tdb_methods *methods = tdb->transaction->io_methods;
tdb_off_t recovery_head;
tdb_len_t recovery_size;
unsigned char *data, *p;
const struct tdb_methods *methods = tdb->transaction->io_methods;
- struct list_struct *rec;
+ struct tdb_record *rec;
tdb_off_t recovery_offset, recovery_max_size;
tdb_off_t old_map_size = tdb->transaction->old_map_size;
uint32_t magic, tailer;
return -1;
}
- rec = (struct list_struct *)data;
+ rec = (struct tdb_record *)data;
memset(rec, 0, sizeof(*rec));
- rec->magic = 0;
+ rec->magic = TDB_RECOVERY_INVALID_MAGIC;
rec->data_len = recovery_size;
rec->rec_len = recovery_max_size;
rec->key_len = old_map_size;
magic = TDB_RECOVERY_MAGIC;
CONVERT(magic);
- *magic_offset = recovery_offset + offsetof(struct list_struct, magic);
+ *magic_offset = recovery_offset + offsetof(struct tdb_record, magic);
if (methods->tdb_write(tdb, *magic_offset, &magic, sizeof(magic)) == -1) {
TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_transaction_setup_recovery: failed to write recovery magic\n"));
return 0;
}
-/*
- commit the current transaction
-*/
-int tdb_transaction_commit(struct tdb_context *tdb)
+static int _tdb_transaction_prepare_commit(struct tdb_context *tdb)
{
const struct tdb_methods *methods;
- tdb_off_t magic_offset = 0;
- uint32_t zero = 0;
- int i;
- tdb_trace(tdb, "tdb_transaction_commit");
if (tdb->transaction == NULL) {
- TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_transaction_commit: no transaction\n"));
+ TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_transaction_prepare_commit: no transaction\n"));
+ return -1;
+ }
+
+ if (tdb->transaction->prepared) {
+ tdb->ecode = TDB_ERR_EINVAL;
+ _tdb_transaction_cancel(tdb, F_WRLCK);
+ TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_transaction_prepare_commit: transaction already prepared\n"));
return -1;
}
if (tdb->transaction->transaction_error) {
tdb->ecode = TDB_ERR_IO;
- tdb_transaction_cancel_internal(tdb);
- TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_transaction_commit: transaction error pending\n"));
+ _tdb_transaction_cancel(tdb, F_RDLCK);
+ TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_transaction_prepare_commit: transaction error pending\n"));
return -1;
}
/* check for a null transaction */
if (tdb->transaction->blocks == NULL) {
- tdb_transaction_cancel_internal(tdb);
return 0;
}
nested their locks properly, so fail the transaction */
if (tdb->num_locks || tdb->global_lock.count) {
tdb->ecode = TDB_ERR_LOCK;
- TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_transaction_commit: locks pending on commit\n"));
- tdb_transaction_cancel_internal(tdb);
+ TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_transaction_prepare_commit: locks pending on commit\n"));
+ _tdb_transaction_cancel(tdb, F_RDLCK);
return -1;
}
/* upgrade the main transaction lock region to a write lock */
if (tdb_brlock_upgrade(tdb, FREELIST_TOP, 0) == -1) {
- TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_transaction_start: failed to upgrade hash locks\n"));
+ TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_transaction_prepare_commit: failed to upgrade hash locks\n"));
tdb->ecode = TDB_ERR_LOCK;
- tdb_transaction_cancel_internal(tdb);
+ _tdb_transaction_cancel(tdb, F_RDLCK);
return -1;
}
/* get the global lock - this prevents new users attaching to the database
during the commit */
- if (tdb_brlock(tdb, GLOBAL_LOCK, F_WRLCK, F_SETLKW, 0, 1) == -1) {
- TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_transaction_commit: failed to get global lock\n"));
+ if (tdb_brlock(tdb, F_WRLCK, GLOBAL_LOCK, 1, TDB_LOCK_WAIT) == -1) {
+ TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_transaction_prepare_commit: failed to get global lock\n"));
tdb->ecode = TDB_ERR_LOCK;
- tdb_transaction_cancel_internal(tdb);
+ _tdb_transaction_cancel(tdb, F_WRLCK);
return -1;
}
+ tdb->transaction->global_lock_taken = true;
+
if (!(tdb->flags & TDB_NOSYNC)) {
/* write the recovery data to the end of the file */
- if (transaction_setup_recovery(tdb, &magic_offset) == -1) {
- TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_transaction_commit: failed to setup recovery data\n"));
- tdb_brlock(tdb, GLOBAL_LOCK, F_UNLCK, F_SETLKW, 0, 1);
- tdb_transaction_cancel_internal(tdb);
+ if (transaction_setup_recovery(tdb, &tdb->transaction->magic_offset) == -1) {
+ TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_transaction_prepare_commit: failed to setup recovery data\n"));
+ _tdb_transaction_cancel(tdb, F_WRLCK);
return -1;
}
}
+ tdb->transaction->prepared = true;
+
/* expand the file to the new size if needed */
if (tdb->map_size != tdb->transaction->old_map_size) {
if (methods->tdb_expand_file(tdb, tdb->transaction->old_map_size,
tdb->map_size -
tdb->transaction->old_map_size) == -1) {
tdb->ecode = TDB_ERR_IO;
- TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_transaction_commit: expansion failed\n"));
- tdb_brlock(tdb, GLOBAL_LOCK, F_UNLCK, F_SETLKW, 0, 1);
- tdb_transaction_cancel_internal(tdb);
+ TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_transaction_prepare_commit: expansion failed\n"));
+ _tdb_transaction_cancel(tdb, F_WRLCK);
return -1;
}
tdb->map_size = tdb->transaction->old_map_size;
methods->tdb_oob(tdb, tdb->map_size + 1, 1);
}
+ /* Keep the global lock until the actual commit */
+
+ return 0;
+}
+
+/*
+ prepare to commit the current transaction
+*/
+int tdb_transaction_prepare_commit(struct tdb_context *tdb)
+{
+ tdb_trace(tdb, "tdb_transaction_prepare_commit");
+ return _tdb_transaction_prepare_commit(tdb);
+}
+
+/*
+ commit the current transaction
+*/
+int tdb_transaction_commit(struct tdb_context *tdb)
+{
+ const struct tdb_methods *methods;
+ int i;
+ bool need_repack;
+
+ if (tdb->transaction == NULL) {
+ TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_transaction_commit: no transaction\n"));
+ return -1;
+ }
+
+ tdb_trace(tdb, "tdb_transaction_commit");
+
+ if (tdb->transaction->transaction_error) {
+ tdb->ecode = TDB_ERR_IO;
+ tdb_transaction_cancel(tdb);
+ TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_transaction_commit: transaction error pending\n"));
+ return -1;
+ }
+
+
+ if (tdb->transaction->nesting != 0) {
+ tdb->transaction->nesting--;
+ return 0;
+ }
+
+ /* check for a null transaction */
+ if (tdb->transaction->blocks == NULL) {
+ _tdb_transaction_cancel(tdb, F_RDLCK);
+ return 0;
+ }
+
+ if (!tdb->transaction->prepared) {
+ int ret = _tdb_transaction_prepare_commit(tdb);
+ if (ret)
+ return ret;
+ }
+
+ methods = tdb->transaction->io_methods;
+
/* perform all the writes */
for (i=0;i<tdb->transaction->num_blocks;i++) {
tdb_off_t offset;
tdb->methods = methods;
tdb_transaction_recover(tdb);
- tdb_transaction_cancel_internal(tdb);
- tdb_brlock(tdb, GLOBAL_LOCK, F_UNLCK, F_SETLKW, 0, 1);
+ _tdb_transaction_cancel(tdb, F_WRLCK);
TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_transaction_commit: write failed\n"));
return -1;
SAFE_FREE(tdb->transaction->blocks);
tdb->transaction->num_blocks = 0;
- if (!(tdb->flags & TDB_NOSYNC)) {
- /* ensure the new data is on disk */
- if (transaction_sync(tdb, 0, tdb->map_size) == -1) {
- return -1;
- }
-
- /* remove the recovery marker */
- if (methods->tdb_write(tdb, magic_offset, &zero, 4) == -1) {
- TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_transaction_commit: failed to remove recovery magic\n"));
- return -1;
- }
-
- /* ensure the recovery marker has been removed on disk */
- if (transaction_sync(tdb, magic_offset, 4) == -1) {
- return -1;
- }
+ /* ensure the new data is on disk */
+ if (transaction_sync(tdb, 0, tdb->map_size) == -1) {
+ return -1;
}
- tdb_brlock(tdb, GLOBAL_LOCK, F_UNLCK, F_SETLKW, 0, 1);
-
/*
TODO: maybe write to some dummy hdr field, or write to magic
offset without mmap, before the last sync, instead of the
utime(tdb->name, NULL);
#endif
+ need_repack = tdb->transaction->need_repack;
+
/* use a transaction cancel to free memory and remove the
transaction locks */
- tdb_transaction_cancel_internal(tdb);
+ _tdb_transaction_cancel(tdb, F_WRLCK);
+
+ if (need_repack) {
+ return tdb_repack(tdb);
+ }
return 0;
}
tdb_off_t recovery_head, recovery_eof;
unsigned char *data, *p;
uint32_t zero = 0;
- struct list_struct rec;
+ struct tdb_record rec;
/* find the recovery area */
if (tdb_ofs_read(tdb, TDB_RECOVERY_HEAD, &recovery_head) == -1) {
}
/* remove the recovery magic */
- if (tdb_ofs_write(tdb, recovery_head + offsetof(struct list_struct, magic),
+ if (tdb_ofs_write(tdb, recovery_head + offsetof(struct tdb_record, magic),
&zero) == -1) {
TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_transaction_recover: failed to remove recovery magic\n"));
tdb->ecode = TDB_ERR_IO;
projects / ccan / blobdiff