to reduce this to 3 or even 2 with some more work.
- check for a valid recovery record on open of the tdb, while the
- global lock is held. Automatically recover from the transaction
+ open lock is held. Automatically recover from the transaction
recovery area if needed, then continue with the open as
usual. This allows for smooth crash recovery with no administrator
intervention.
still available, but no transaction recovery area is used and no
fsync/msync calls are made.
+ - 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.
*/
bool prepared;
tdb_off_t magic_offset;
+ /* set when the OPEN_LOCK has been taken */
+ bool open_lock_taken;
+
/* old file size before transaction */
tdb_len_t old_map_size;
{
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_read: transaction already prepared, read not allowed\n"));
- tdb->transaction->transaction_error = 1;
- return -1;
- }
-
/* break it down into block sized ops */
while (len + (off % tdb->transaction->block_size) > tdb->transaction->block_size) {
tdb_len_t len2 = tdb->transaction->block_size - (off % tdb->transaction->block_size);
if (len <= tdb->map_size) {
return 0;
}
- return TDB_ERRCODE(TDB_ERR_IO, -1);
+ tdb->ecode = TDB_ERR_IO;
+ return -1;
}
/*
/*
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
};
/* cope with nested tdb_transaction_start() calls */
if (tdb->transaction != NULL) {
+ if (!(tdb->flags & TDB_ALLOW_NESTING)) {
+ tdb->ecode = TDB_ERR_NESTING;
+ return -1;
+ }
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) {
+ if (tdb->num_locks != 0 || tdb->allrecord_lock.count) {
/* the caller must not have any locks when starting a
transaction as otherwise we'll be screwed by lack
of nested locks in posix */
/* 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);
return 0;
}
- if (fsync(tdb->fd) != 0) {
+ if (fdatasync(tdb->fd) != 0) {
tdb->ecode = TDB_ERR_IO;
TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_transaction: fsync failed\n"));
return -1;
}
-/*
- cancel the current transaction
-*/
-int tdb_transaction_cancel(struct tdb_context *tdb)
+/* ltype is F_WRLCK after prepare. */
+static int _tdb_transaction_cancel(struct tdb_context *tdb, int ltype)
{
int i, ret = 0;
if (tdb->transaction->magic_offset) {
const struct tdb_methods *methods = tdb->transaction->io_methods;
- uint32_t zero = 0;
+ const uint32_t invalid = TDB_RECOVERY_INVALID_MAGIC;
/* remove the recovery marker */
- if (methods->tdb_write(tdb, tdb->transaction->magic_offset, &zero, 4) == -1 ||
+ 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->open_lock_taken) {
+ tdb_brunlock(tdb, F_WRLCK, OPEN_LOCK, 1);
+ tdb->transaction->open_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->global_lock.count = 0;
+ if (tdb->allrecord_lock.count != 0) {
+ tdb_brunlock(tdb, tdb->allrecord_lock.ltype,
+ FREELIST_TOP, 4*tdb->header.hash_size);
+ tdb->allrecord_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 ret;
}
+/*
+ cancel the current transaction
+*/
+int tdb_transaction_cancel(struct tdb_context *tdb)
+{
+ int ltype = F_RDLCK;
+ tdb_trace(tdb, "tdb_transaction_cancel");
+ if (tdb->transaction && tdb->transaction->prepared)
+ ltype = F_WRLCK;
+ return _tdb_transaction_cancel(tdb, ltype);
+}
/*
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;
rec.rec_len = 0;
- if (recovery_head != 0 &&
- methods->tdb_read(tdb, recovery_head, &rec, sizeof(rec), DOCONV()) == -1) {
- TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_recovery_allocate: failed to read recovery record\n"));
- return -1;
+ if (recovery_head != 0) {
+ if (methods->tdb_read(tdb, recovery_head, &rec, sizeof(rec), DOCONV()) == -1) {
+ TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_recovery_allocate: failed to read recovery record\n"));
+ return -1;
+ }
+ /* ignore invalid recovery regions: can happen in crash */
+ if (rec.magic != TDB_RECOVERY_MAGIC &&
+ rec.magic != TDB_RECOVERY_INVALID_MAGIC) {
+ recovery_head = 0;
+ }
}
*recovery_size = tdb_recovery_size(tdb);
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;
}
-/*
- prepare to commit the current transaction
-*/
-int tdb_transaction_prepare_commit(struct tdb_context *tdb)
+static int _tdb_transaction_prepare_commit(struct tdb_context *tdb)
{
const struct tdb_methods *methods;
if (tdb->transaction->prepared) {
tdb->ecode = TDB_ERR_EINVAL;
- tdb_transaction_cancel(tdb);
+ _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(tdb);
+ _tdb_transaction_cancel(tdb, F_RDLCK);
TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_transaction_prepare_commit: transaction error pending\n"));
return -1;
}
/* if there are any locks pending then the caller has not
nested their locks properly, so fail the transaction */
- if (tdb->num_locks || tdb->global_lock.count) {
+ if (tdb->num_locks || tdb->allrecord_lock.count) {
tdb->ecode = TDB_ERR_LOCK;
TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_transaction_prepare_commit: locks pending on commit\n"));
- tdb_transaction_cancel(tdb);
+ _tdb_transaction_cancel(tdb, F_RDLCK);
return -1;
}
if (tdb_brlock_upgrade(tdb, FREELIST_TOP, 0) == -1) {
TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_transaction_prepare_commit: failed to upgrade hash locks\n"));
tdb->ecode = TDB_ERR_LOCK;
- tdb_transaction_cancel(tdb);
+ _tdb_transaction_cancel(tdb, F_RDLCK);
return -1;
}
- /* get the global lock - this prevents new users attaching to the database
+ /* get the open 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_prepare_commit: failed to get global lock\n"));
+ if (tdb_brlock(tdb, F_WRLCK, OPEN_LOCK, 1, TDB_LOCK_WAIT) == -1) {
+ TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_transaction_prepare_commit: failed to get open lock\n"));
tdb->ecode = TDB_ERR_LOCK;
- tdb_transaction_cancel(tdb);
+ _tdb_transaction_cancel(tdb, F_WRLCK);
return -1;
}
+ tdb->transaction->open_lock_taken = true;
+
if (!(tdb->flags & TDB_NOSYNC)) {
/* write the recovery data to the end of the file */
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_brlock(tdb, GLOBAL_LOCK, F_UNLCK, F_SETLKW, 0, 1);
- tdb_transaction_cancel(tdb);
+ _tdb_transaction_cancel(tdb, F_WRLCK);
return -1;
}
}
tdb->transaction->old_map_size) == -1) {
tdb->ecode = TDB_ERR_IO;
TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_transaction_prepare_commit: expansion failed\n"));
- tdb_brlock(tdb, GLOBAL_LOCK, F_UNLCK, F_SETLKW, 0, 1);
- tdb_transaction_cancel(tdb);
+ _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 */
+ /* Keep the open 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
*/
return -1;
}
+ tdb_trace(tdb, "tdb_transaction_commit");
+
if (tdb->transaction->transaction_error) {
tdb->ecode = TDB_ERR_IO;
- tdb_transaction_cancel(tdb);
+ _tdb_transaction_cancel(tdb, F_RDLCK);
TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_transaction_commit: transaction error pending\n"));
return -1;
}
/* check for a null transaction */
if (tdb->transaction->blocks == NULL) {
- tdb_transaction_cancel(tdb);
+ _tdb_transaction_cancel(tdb, F_RDLCK);
return 0;
}
if (!tdb->transaction->prepared) {
- int ret = tdb_transaction_prepare_commit(tdb);
+ int ret = _tdb_transaction_prepare_commit(tdb);
if (ret)
return ret;
}
tdb->methods = methods;
tdb_transaction_recover(tdb);
- tdb_transaction_cancel(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;
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
/* use a transaction cancel to free memory and remove the
transaction locks */
- tdb_transaction_cancel(tdb);
+ _tdb_transaction_cancel(tdb, F_WRLCK);
if (need_repack) {
return tdb_repack(tdb);
/*
recover from an aborted transaction. Must be called with exclusive
- database write access already established (including the global
+ database write access already established (including the open
lock to prevent new processes attaching)
*/
int tdb_transaction_recover(struct tdb_context *tdb)
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;
git.samba.org / samba.git / blobdiff