tdb: add TDB_DISALLOW_NESTING and make TDB_ALLOW_NESTING the default behavior
We need to keep TDB_ALLOW_NESTING as default behavior,
so that existing code continues to work.
However we may change the default together with a major version
number change in future.
metze
(cherry picked from samba commit
3b9f19ed919fef2e88b2f92ae541e07bc7379cd1)
Signed-off-by: Stefan Metzmacher <metze@samba.org>
tdb->flags &= ~TDB_CLEAR_IF_FIRST;
}
+ if ((tdb->flags & TDB_ALLOW_NESTING) &&
+ (tdb->flags & TDB_DISALLOW_NESTING)) {
+ tdb->ecode = TDB_ERR_NESTING;
+ TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_open_ex: "
+ "allow_nesting and disallow_nesting are not allowed together!"));
+ errno = EINVAL;
+ goto fail;
+ }
+
+ /*
+ * TDB_ALLOW_NESTING is the default behavior.
+ * Note: this may change in future versions!
+ */
+ if (!(tdb->flags & TDB_DISALLOW_NESTING)) {
+ tdb->flags |= TDB_ALLOW_NESTING;
+ }
+
/* internal databases don't mmap or lock, and start off cleared */
if (tdb->flags & TDB_INTERNAL) {
tdb->flags |= (TDB_NOLOCK | TDB_NOMMAP);
void tdb_add_flags(struct tdb_context *tdb, unsigned flags)
{
+ if ((flags & TDB_ALLOW_NESTING) &&
+ (flags & TDB_DISALLOW_NESTING)) {
+ tdb->ecode = TDB_ERR_NESTING;
+ TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_add_flags: "
+ "allow_nesting and disallow_nesting are not allowed together!"));
+ return;
+ }
+
+ if (flags & TDB_ALLOW_NESTING) {
+ tdb->flags &= ~TDB_DISALLOW_NESTING;
+ }
+ if (flags & TDB_DISALLOW_NESTING) {
+ tdb->flags &= ~TDB_ALLOW_NESTING;
+ }
+
tdb->flags |= flags;
}
void tdb_remove_flags(struct tdb_context *tdb, unsigned flags)
{
+ if ((flags & TDB_ALLOW_NESTING) &&
+ (flags & TDB_DISALLOW_NESTING)) {
+ tdb->ecode = TDB_ERR_NESTING;
+ TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_remove_flags: "
+ "allow_nesting and disallow_nesting are not allowed together!"));
+ return;
+ }
+
+ if (flags & TDB_ALLOW_NESTING) {
+ tdb->flags |= TDB_DISALLOW_NESTING;
+ }
+ if (flags & TDB_DISALLOW_NESTING) {
+ tdb->flags |= TDB_ALLOW_NESTING;
+ }
+
tdb->flags &= ~flags;
}
#define TDB_SEQNUM 128 /* maintain a sequence number */
#define TDB_VOLATILE 256 /* Activate the per-hashchain freelist, default 5 */
#define TDB_ALLOW_NESTING 512 /* Allow transactions to nest */
+#define TDB_DISALLOW_NESTING 1024 /* Disallow transactions to nest */
/* error codes */
enum TDB_ERROR {TDB_SUCCESS=0, TDB_ERR_CORRUPT, TDB_ERR_IO, TDB_ERR_LOCK,
fsync/msync calls are made.
- if TDB_ALLOW_NESTING is passed to flags in tdb open, or added using
- tdb_add_flags() transaction is enabled.
- The default is that transaction nesting is not allowed and an attempt
- to create a nested transaction will fail with TDB_ERR_NESTING.
+ 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.
*/