-/* Copyright (c) 2009, 2010, 2011 Nicira Networks.
+/* Copyright (c) 2009, 2010, 2011, 2012 Nicira, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
unsigned int commit_seqno;
/* Increments. */
- char *inc_table;
- char *inc_column;
- struct json *inc_where;
+ const char *inc_table;
+ const char *inc_column;
+ struct uuid inc_row;
unsigned int inc_index;
int64_t inc_new_value;
}
}
-/* Processes a batch of messages from the database server on 'idl'. Returns
- * true if the database as seen through 'idl' changed, false if it did not
- * change. The initial fetch of the entire contents of the remote database is
- * considered to be one kind of change. If 'idl' has been configured to
- * acquire a database lock (with ovsdb_idl_set_lock()), then successfully
- * acquiring the lock is also considered to be a change.
- *
- * When this function returns false, the client may continue to use any data
- * structures it obtained from 'idl' in the past. But when it returns true,
- * the client must not access any of these data structures again, because they
- * could have freed or reused for other purposes.
- *
- * This function can return occasional false positives, that is, report that
- * the database changed even though it didn't. This happens if the connection
- * to the database drops and reconnects, which causes the database contents to
- * be reloaded even if they didn't change. (It could also happen if the
- * database server sends out a "change" that reflects what we already thought
- * was in the database, but the database server is not supposed to do that.)
- *
- * As an alternative to checking the return value, the client may check for
- * changes in the value returned by ovsdb_idl_get_seqno().
- */
-bool
+/* Processes a batch of messages from the database server on 'idl'. This may
+ * cause the IDL's contents to change. The client may check for that with
+ * ovsdb_idl_get_seqno(). */
+void
ovsdb_idl_run(struct ovsdb_idl *idl)
{
- unsigned int initial_change_seqno = idl->change_seqno;
int i;
assert(!idl->txn);
}
jsonrpc_msg_destroy(msg);
}
-
- return initial_change_seqno != idl->change_seqno;
}
/* Arranges for poll_block() to wake up when ovsdb_idl_run() has something to
jsonrpc_session_recv_wait(idl->session);
}
-/* Returns a number that represents the state of 'idl'. When 'idl' is updated
- * (by ovsdb_idl_run()), the return value changes. */
+/* Returns a "sequence number" that represents the state of 'idl'. When
+ * ovsdb_idl_run() changes the database, the sequence number changes. The
+ * initial fetch of the entire contents of the remote database is considered to
+ * be one kind of change. Successfully acquiring a lock, if one has been
+ * configured with ovsdb_idl_set_lock(), is also considered to be a change.
+ *
+ * As long as the sequence number does not change, the client may continue to
+ * use any data structures it obtains from 'idl'. But when it changes, the
+ * client must not access any of these data structures again, because they
+ * could have freed or reused for other purposes.
+ *
+ * The sequence number can occasionally change even if the database does not.
+ * This happens if the connection to the database drops and reconnects, which
+ * causes the database contents to be reloaded even if they didn't change. (It
+ * could also happen if the database server sends out a "change" that reflects
+ * what the IDL already thought was in the database. The database server is
+ * not supposed to do that, but bugs could in theory cause it to do so.) */
unsigned int
ovsdb_idl_get_seqno(const struct ovsdb_idl *idl)
{
ovsdb_idl_row_create__(const struct ovsdb_idl_table_class *class)
{
struct ovsdb_idl_row *row = xzalloc(class->allocation_size);
+ class->row_init(row);
list_init(&row->src_arcs);
list_init(&row->dst_arcs);
hmap_node_nullify(&row->txn_node);
return &idl->tables[table_class - idl->class->tables];
}
+/* Called by ovsdb-idlc generated code. */
struct ovsdb_idl_row *
ovsdb_idl_get_row_arc(struct ovsdb_idl_row *src,
struct ovsdb_idl_table_class *dst_table_class,
}
}
+/* Searches 'tc''s table in 'idl' for a row with UUID 'uuid'. Returns a
+ * pointer to the row if there is one, otherwise a null pointer. */
const struct ovsdb_idl_row *
ovsdb_idl_get_row_for_uuid(const struct ovsdb_idl *idl,
const struct ovsdb_idl_table_class *tc,
return NULL;
}
+/* Returns a row in 'table_class''s table in 'idl', or a null pointer if that
+ * table is empty.
+ *
+ * Database tables are internally maintained as hash tables, so adding or
+ * removing rows while traversing the same table can cause some rows to be
+ * visited twice or not at apply. */
const struct ovsdb_idl_row *
ovsdb_idl_first_row(const struct ovsdb_idl *idl,
const struct ovsdb_idl_table_class *table_class)
return next_real_row(table, hmap_first(&table->rows));
}
+/* Returns a row following 'row' within its table, or a null pointer if 'row'
+ * is the last row in its table. */
const struct ovsdb_idl_row *
ovsdb_idl_next_row(const struct ovsdb_idl_row *row)
{
ovsdb_idl_read(const struct ovsdb_idl_row *row,
const struct ovsdb_idl_column *column)
{
- const struct ovsdb_idl_table_class *class = row->table->class;
- size_t column_idx = column - class->columns;
+ const struct ovsdb_idl_table_class *class;
+ size_t column_idx;
+
+ assert(!ovsdb_idl_row_is_synthetic(row));
+
+ class = row->table->class;
+ column_idx = column - class->columns;
assert(row->new != NULL);
assert(column_idx < class->n_columns);
static void ovsdb_idl_txn_complete(struct ovsdb_idl_txn *txn,
enum ovsdb_idl_txn_status);
+/* Returns a string representation of 'status'. The caller must not modify or
+ * free the returned string.
+ *
+ * The return value is probably useful only for debug log messages and unit
+ * tests. */
const char *
ovsdb_idl_txn_status_to_string(enum ovsdb_idl_txn_status status)
{
return "aborted";
case TXN_SUCCESS:
return "success";
- case TXN_AGAIN_WAIT:
- return "wait then try again";
- case TXN_AGAIN_NOW:
- return "try again now";
+ case TXN_TRY_AGAIN:
+ return "try again";
case TXN_NOT_LOCKED:
return "not locked";
case TXN_ERROR:
return "<unknown>";
}
+/* Starts a new transaction on 'idl'. A given ovsdb_idl may only have a single
+ * active transaction at a time. See the large comment in ovsdb-idl.h for
+ * general information on transactions. */
struct ovsdb_idl_txn *
ovsdb_idl_txn_create(struct ovsdb_idl *idl)
{
txn->inc_table = NULL;
txn->inc_column = NULL;
- txn->inc_where = NULL;
hmap_init(&txn->inserted_rows);
va_end(args);
}
+/* Marks 'txn' as a transaction that will not actually modify the database. In
+ * almost every way, the transaction is treated like other transactions. It
+ * must be committed or aborted like other transactions, it will be sent to the
+ * database server like other transactions, and so on. The only difference is
+ * that the operations sent to the database server will include, as the last
+ * step, an "abort" operation, so that any changes made by the transaction will
+ * not actually take effect. */
void
ovsdb_idl_txn_set_dry_run(struct ovsdb_idl_txn *txn)
{
txn->dry_run = true;
}
+/* Causes 'txn', when committed, to increment the value of 'column' within
+ * 'row' by 1. 'column' must have an integer type. After 'txn' commits
+ * successfully, the client may retrieve the final (incremented) value of
+ * 'column' with ovsdb_idl_txn_get_increment_new_value().
+ *
+ * The client could accomplish something similar with ovsdb_idl_read(),
+ * ovsdb_idl_txn_verify() and ovsdb_idl_txn_write(), or with ovsdb-idlc
+ * generated wrappers for these functions. However, ovsdb_idl_txn_increment()
+ * will never (by itself) fail because of a verify error.
+ *
+ * The intended use is for incrementing the "next_cfg" column in the
+ * Open_vSwitch table. */
void
-ovsdb_idl_txn_increment(struct ovsdb_idl_txn *txn, const char *table,
- const char *column, const struct json *where)
+ovsdb_idl_txn_increment(struct ovsdb_idl_txn *txn,
+ const struct ovsdb_idl_row *row,
+ const struct ovsdb_idl_column *column)
{
assert(!txn->inc_table);
- txn->inc_table = xstrdup(table);
- txn->inc_column = xstrdup(column);
- txn->inc_where = where ? json_clone(where) : json_array_create_empty();
+ assert(column->type.key.type == OVSDB_TYPE_INTEGER);
+ assert(column->type.value.type == OVSDB_TYPE_VOID);
+
+ txn->inc_table = row->table->class->name;
+ txn->inc_column = column->name;
+ txn->inc_row = row->uuid;
}
+/* Destroys 'txn' and frees all associated memory. If ovsdb_idl_txn_commit()
+ * has been called for 'txn' but the commit is still incomplete (that is, the
+ * last call returned TXN_INCOMPLETE) then the transaction may or may not still
+ * end up committing at the database server, but the client will not be able to
+ * get any further status information back. */
void
ovsdb_idl_txn_destroy(struct ovsdb_idl_txn *txn)
{
ovsdb_idl_txn_abort(txn);
ds_destroy(&txn->comment);
free(txn->error);
- free(txn->inc_table);
- free(txn->inc_column);
- json_destroy(txn->inc_where);
HMAP_FOR_EACH_SAFE (insert, next, hmap_node, &txn->inserted_rows) {
free(insert);
}
free(txn);
}
+/* Causes poll_block() to wake up if 'txn' has completed committing. */
void
ovsdb_idl_txn_wait(const struct ovsdb_idl_txn *txn)
{
hmap_init(&txn->txn_rows);
}
+/* Attempts to commit 'txn'. Returns the status of the commit operation, one
+ * of the following TXN_* constants:
+ *
+ * TXN_INCOMPLETE:
+ *
+ * The transaction is in progress, but not yet complete. The caller
+ * should call again later, after calling ovsdb_idl_run() to let the IDL
+ * do OVSDB protocol processing.
+ *
+ * TXN_UNCHANGED:
+ *
+ * The transaction is complete. (It didn't actually change the database,
+ * so the IDL didn't send any request to the database server.)
+ *
+ * TXN_ABORTED:
+ *
+ * The caller previously called ovsdb_idl_txn_abort().
+ *
+ * TXN_SUCCESS:
+ *
+ * The transaction was successful. The update made by the transaction
+ * (and possibly other changes made by other database clients) should
+ * already be visible in the IDL.
+ *
+ * TXN_TRY_AGAIN:
+ *
+ * The transaction failed for some transient reason, e.g. because a
+ * "verify" operation reported an inconsistency or due to a network
+ * problem. The caller should wait for a change to the database, then
+ * compose a new transaction, and commit the new transaction.
+ *
+ * Use the return value of ovsdb_idl_get_seqno() to wait for a change in
+ * the database. It is important to use its return value *before* the
+ * initial call to ovsdb_idl_txn_commit() as the baseline for this
+ * purpose, because the change that one should wait for can happen after
+ * the initial call but before the call that returns TXN_TRY_AGAIN, and
+ * using some other baseline value in that situation could cause an
+ * indefinite wait if the database rarely changes.
+ *
+ * TXN_NOT_LOCKED:
+ *
+ * The transaction failed because the IDL has been configured to require
+ * a database lock (with ovsdb_idl_set_lock()) but didn't get it yet or
+ * has already lost it.
+ *
+ * Committing a transaction rolls back all of the changes that it made to the
+ * IDL's copy of the database. If the transaction commits successfully, then
+ * the database server will send an update and, thus, the IDL will be updated
+ * with the committed changes. */
enum ovsdb_idl_txn_status
ovsdb_idl_txn_commit(struct ovsdb_idl_txn *txn)
{
json_object_put_string(op, "op", "mutate");
json_object_put_string(op, "table", txn->inc_table);
json_object_put(op, "where",
- substitute_uuids(json_clone(txn->inc_where), txn));
+ substitute_uuids(where_uuid_equals(&txn->inc_row),
+ txn));
json_object_put(op, "mutations",
json_array_create_1(
json_array_create_3(
json_object_put_string(op, "op", "select");
json_object_put_string(op, "table", txn->inc_table);
json_object_put(op, "where",
- substitute_uuids(json_clone(txn->inc_where), txn));
+ substitute_uuids(where_uuid_equals(&txn->inc_row),
+ txn));
json_object_put(op, "columns",
json_array_create_1(json_string_create(
txn->inc_column)));
json_hash(txn->request_id, 0));
txn->status = TXN_INCOMPLETE;
} else {
- txn->status = TXN_AGAIN_WAIT;
+ txn->status = TXN_TRY_AGAIN;
}
ovsdb_idl_txn_disassemble(txn);
/* Attempts to commit 'txn', blocking until the commit either succeeds or
* fails. Returns the final commit status, which may be any TXN_* value other
- * than TXN_INCOMPLETE. */
+ * than TXN_INCOMPLETE.
+ *
+ * This function calls ovsdb_idl_run() on 'txn''s IDL, so it may cause the
+ * return value of ovsdb_idl_get_seqno() to change. */
enum ovsdb_idl_txn_status
ovsdb_idl_txn_commit_block(struct ovsdb_idl_txn *txn)
{
return status;
}
+/* Returns the final (incremented) value of the column in 'txn' that was set to
+ * be incremented by ovsdb_idl_txn_increment(). 'txn' must have committed
+ * successfully. */
int64_t
ovsdb_idl_txn_get_increment_new_value(const struct ovsdb_idl_txn *txn)
{
return txn->inc_new_value;
}
+/* Aborts 'txn' without sending it to the database server. This is effective
+ * only if ovsdb_idl_txn_commit() has not yet been called for 'txn'.
+ * Otherwise, it has no effect.
+ *
+ * Aborting a transaction doesn't free its memory. Use
+ * ovsdb_idl_txn_destroy() to do that. */
void
ovsdb_idl_txn_abort(struct ovsdb_idl_txn *txn)
{
}
}
+/* Returns a string that reports the error status for 'txn'. The caller must
+ * not modify or free the returned string. A call to ovsdb_idl_txn_destroy()
+ * for 'txn' may free the returned string.
+ *
+ * The return value is ordinarily one of the strings that
+ * ovsdb_idl_txn_status_to_string() would return, but if the transaction failed
+ * due to an error reported by the database server, the return value is that
+ * error. */
const char *
ovsdb_idl_txn_get_error(const struct ovsdb_idl_txn *txn)
{
size_t column_idx;
if (ovsdb_idl_row_is_synthetic(row)) {
+ ovsdb_datum_destroy(datum, &column->type);
return;
}
struct ovsdb_idl_txn *txn;
HMAP_FOR_EACH (txn, hmap_node, &idl->outstanding_txns) {
- ovsdb_idl_txn_complete(txn, TXN_AGAIN_WAIT);
+ ovsdb_idl_txn_complete(txn, TXN_TRY_AGAIN);
}
}
status = (hard_errors ? TXN_ERROR
: lock_errors ? TXN_NOT_LOCKED
- : soft_errors ? (txn->commit_seqno == idl->change_seqno
- ? TXN_AGAIN_WAIT
- : TXN_AGAIN_NOW)
+ : soft_errors ? TXN_TRY_AGAIN
: TXN_SUCCESS);
}
return true;
}
+/* Returns the transaction currently active for 'row''s IDL. A transaction
+ * must currently be active. */
struct ovsdb_idl_txn *
ovsdb_idl_txn_get(const struct ovsdb_idl_row *row)
{
return txn;
}
+/* Returns the IDL on which 'txn' acts. */
struct ovsdb_idl *
ovsdb_idl_txn_get_idl (struct ovsdb_idl_txn *txn)
{
git://git.onelab.eu / sliver-openvswitch.git / blobdiff