#define TDB_CONVERT 16 /* convert endian */
#define TDB_NOSYNC 64 /* don't use synchronous transactions */
#define TDB_SEQNUM 128 /* maintain a sequence number */
+#define TDB_ALLOW_NESTING 256 /* fake nested transactions */
/**
* tdb_close - close and free a tdb.
* to read the tdb, but not alter it (they will block), nor will they see
* any changes until tdb_transaction_commit() is called.
*
+ * Note that if the TDB_ALLOW_NESTING flag is set, a tdb_transaction_start()
+ * within a transaction will succeed, but it's not a real transaction:
+ * (1) An inner transaction which is committed is not actually committed until
+ * the outer transaction is; if the outer transaction is cancelled, the
+ * inner ones are discarded.
+ * (2) tdb_transaction_cancel() marks the outer transaction as having an error,
+ * so the final tdb_transaction_commit() will fail.
+ * (3) the outer transaction will see the results of the inner transaction.
+ *
* See Also:
* tdb_transaction_cancel, tdb_transaction_commit.
*/
/**
* tdb_add_flag - set a flag for a tdb
* @tdb: the tdb context returned from tdb_open()
- * @flag: one of TDB_NOLOCK, TDB_NOMMAP or TDB_NOSYNC.
+ * @flag: one of TDB_NOLOCK, TDB_NOMMAP, TDB_NOSYNC or TDB_ALLOW_NESTING.
*
* You can use this to set a flag on the TDB. You cannot set these flags
* on a TDB_INTERNAL tdb.
/**
* tdb_remove_flag - unset a flag for a tdb
* @tdb: the tdb context returned from tdb_open()
- * @flag: one of TDB_NOLOCK, TDB_NOMMAP or TDB_NOSYNC.
+ * @flag: one of TDB_NOLOCK, TDB_NOMMAP, TDB_NOSYNC or TDB_ALLOW_NESTING.
*
* You can use this to clear a flag on the TDB. You cannot clear flags
* on a TDB_INTERNAL tdb.
*/
void tdb_remove_flag(struct tdb_context *tdb, unsigned flag);
+/**
+ * enum tdb_attribute_type - descriminator for union tdb_attribute.
+ */
+enum tdb_attribute_type {
+ TDB_ATTRIBUTE_LOG = 0,
+ TDB_ATTRIBUTE_HASH = 1,
+ TDB_ATTRIBUTE_SEED = 2,
+ TDB_ATTRIBUTE_STATS = 3,
+ TDB_ATTRIBUTE_OPENHOOK = 4,
+ TDB_ATTRIBUTE_FLOCK = 5
+};
+
+/**
+ * tdb_get_attribute - get an attribute for an existing tdb
+ * @tdb: the tdb context returned from tdb_open()
+ * @attr: the union tdb_attribute to set.
+ *
+ * This gets an attribute from a TDB which has previously been set (or
+ * may return the default values). Set @attr.base.attr to the
+ * attribute type you want get.
+ *
+ * Currently this does not work for TDB_ATTRIBUTE_OPENHOOK.
+ */
+enum TDB_ERROR tdb_get_attribute(struct tdb_context *tdb,
+ union tdb_attribute *attr);
+
+/**
+ * tdb_set_attribute - set an attribute for an existing tdb
+ * @tdb: the tdb context returned from tdb_open()
+ * @attr: the union tdb_attribute to set.
+ *
+ * This sets an attribute on a TDB, overriding any previous attribute
+ * of the same type. It returns TDB_ERR_EINVAL if the attribute is
+ * unknown or invalid.
+ *
+ * Note that TDB_ATTRIBUTE_HASH, TDB_ATTRIBUTE_SEED and
+ * TDB_ATTRIBUTE_OPENHOOK cannot currently be set after tdb_open.
+ */
+enum TDB_ERROR tdb_set_attribute(struct tdb_context *tdb,
+ const union tdb_attribute *attr);
+
+/**
+ * tdb_unset_attribute - reset an attribute for an existing tdb
+ * @tdb: the tdb context returned from tdb_open()
+ * @type: the attribute type to unset.
+ *
+ * This unsets an attribute on a TDB, returning it to the defaults
+ * (where applicable).
+ *
+ * Note that it only makes sense for TDB_ATTRIBUTE_LOG and TDB_ATTRIBUTE_FLOCK
+ * to be unset.
+ */
+void tdb_unset_attribute(struct tdb_context *tdb,
+ enum tdb_attribute_type type);
+
/**
* tdb_name - get the name of a tdb
* @tdb: the tdb context returned from tdb_open()
*/
int tdb_fd(const struct tdb_context *tdb);
-/**
- * enum tdb_attribute_type - descriminator for union tdb_attribute.
- */
-enum tdb_attribute_type {
- TDB_ATTRIBUTE_LOG = 0,
- TDB_ATTRIBUTE_HASH = 1,
- TDB_ATTRIBUTE_SEED = 2,
- TDB_ATTRIBUTE_STATS = 3,
- TDB_ATTRIBUTE_OPENHOOK = 4,
- TDB_ATTRIBUTE_FLOCK = 5
-};
-
/**
* struct tdb_attribute_base - common fields for all tdb attributes.
*/
* struct tdb_attribute_stats - tdb operational statistics
*
* This attribute records statistics of various low-level TDB operations.
- * This can be used to assist performance evaluation.
+ * This can be used to assist performance evaluation. This is only
+ * useful for tdb_get_attribute().
*
* New fields will be added at the end, hence the "size" argument which
- * indicates how large your structure is. If your size is larger than
- * that known about by this version of tdb, the size will be reduced to
- * the known structure size. Thus you can detect older versions, and
- * thus know that newer stats will not be updated.
+ * indicates how large your structure is: it must be filled in before
+ * calling tdb_get_attribute(), which will overwrite it with the size
+ * tdb knows about.
*/
struct tdb_attribute_stats {
struct tdb_attribute_base base; /* .attr = TDB_ATTRIBUTE_STATS */
uint64_t alloc_bucket_max;
uint64_t alloc_leftover;
uint64_t alloc_coalesce_tried;
+ uint64_t alloc_coalesce_iterate_clash;
uint64_t alloc_coalesce_lockfail;
uint64_t alloc_coalesce_race;
uint64_t alloc_coalesce_succeeded;
- uint64_t alloc_coalesce_num_merged;
+ uint64_t alloc_coalesce_num_merged;
uint64_t compares;
uint64_t compare_wrong_bucket;
uint64_t compare_wrong_offsetbits;
uint64_t compare_wrong_keylen;
uint64_t compare_wrong_rechash;
uint64_t compare_wrong_keycmp;
+ uint64_t transactions;
+ uint64_t transaction_cancel;
+ uint64_t transaction_nest;
+ uint64_t transaction_expand_file;
+ uint64_t transaction_read_direct;
+ uint64_t transaction_read_direct_fail;
+ uint64_t transaction_write_direct;
+ uint64_t transaction_write_direct_fail;
uint64_t expands;
uint64_t frees;
uint64_t locks;
- uint64_t lock_lowlevel;
- uint64_t lock_nonblock;
+ uint64_t lock_lowlevel;
+ uint64_t lock_nonblock;
+ uint64_t lock_nonblock_fail;
};
/**