epoch_leave( epoch );
}
-LloadConnection *
-backend_select( LloadOperation *op, int *res )
+int
+try_upstream(
+ LloadBackend *b,
+ lload_c_head *head,
+ LloadOperation *op,
+ LloadConnection *c,
+ int *res,
+ char **message )
+{
+ assert_locked( &b->b_mutex );
+
+ checked_lock( &c->c_io_mutex );
+ CONNECTION_LOCK(c);
+ if ( c->c_state == LLOAD_C_READY && !c->c_pendingber &&
+ ( b->b_max_conn_pending == 0 ||
+ c->c_n_ops_executing < b->b_max_conn_pending ) ) {
+ Debug( LDAP_DEBUG_CONNS, "try_upstream: "
+ "selected connection connid=%lu for client "
+ "connid=%lu msgid=%d\n",
+ c->c_connid, op->o_client_connid, op->o_client_msgid );
+
+ /* c_state is DYING if we're about to be unlinked */
+ assert( IS_ALIVE( c, c_live ) );
+
+ if ( head ) {
+ /*
+ * Round-robin step:
+ * Rotate the queue to put this connection at the end.
+ */
+ LDAP_CIRCLEQ_MAKE_TAIL( head, c, c_next );
+ }
+
+ b->b_n_ops_executing++;
+ if ( op->o_tag == LDAP_REQ_BIND ) {
+ b->b_counters[LLOAD_STATS_OPS_BIND].lc_ops_received++;
+ } else {
+ b->b_counters[LLOAD_STATS_OPS_OTHER].lc_ops_received++;
+ }
+ c->c_n_ops_executing++;
+ c->c_counters.lc_ops_received++;
+
+ *res = LDAP_SUCCESS;
+ CONNECTION_ASSERT_LOCKED(c);
+ assert_locked( &c->c_io_mutex );
+ return 1;
+ }
+ CONNECTION_UNLOCK(c);
+ checked_unlock( &c->c_io_mutex );
+ return 0;
+}
+
+int
+backend_select(
+ LloadBackend *b,
+ LloadOperation *op,
+ LloadConnection **cp,
+ int *res,
+ char **message )
+{
+ lload_c_head *head;
+ LloadConnection *c;
+
+ assert_locked( &b->b_mutex );
+ if ( b->b_max_pending && b->b_n_ops_executing >= b->b_max_pending ) {
+ Debug( LDAP_DEBUG_CONNS, "backend_select: "
+ "backend %s too busy\n",
+ b->b_uri.bv_val );
+ *res = LDAP_BUSY;
+ *message = "server busy";
+ return 1;
+ }
+
+ if ( op->o_tag == LDAP_REQ_BIND
+#ifdef LDAP_API_FEATURE_VERIFY_CREDENTIALS
+ && !(lload_features & LLOAD_FEATURE_VC)
+#endif /* LDAP_API_FEATURE_VERIFY_CREDENTIALS */
+ ) {
+ head = &b->b_bindconns;
+ } else {
+ head = &b->b_conns;
+ }
+
+ if ( LDAP_CIRCLEQ_EMPTY( head ) ) {
+ return 0;
+ }
+
+ *res = LDAP_BUSY;
+ *message = "server busy";
+
+ LDAP_CIRCLEQ_FOREACH( c, head, c_next ) {
+ if ( try_upstream( b, head, op, c, res, message ) ) {
+ *cp = c;
+ CONNECTION_ASSERT_LOCKED(c);
+ assert_locked( &c->c_io_mutex );
+ return 1;
+ }
+ }
+
+ return 1;
+}
+
+int
+upstream_select(
+ LloadOperation *op,
+ LloadConnection **cp,
+ int *res,
+ char **message )
{
LloadBackend *b, *first, *next;
+ int rc = 0;
checked_lock( &backend_mutex );
first = b = current_backend;
/* TODO: Two runs, one with trylock, then one actually locked if we don't
* find anything? */
do {
- lload_c_head *head;
- LloadConnection *c;
-
checked_lock( &b->b_mutex );
next = LDAP_CIRCLEQ_LOOP_NEXT( &backend, b, b_next );
- if ( b->b_max_pending && b->b_n_ops_executing >= b->b_max_pending ) {
- Debug( LDAP_DEBUG_CONNS, "backend_select: "
- "backend %s too busy\n",
- b->b_uri.bv_val );
- checked_unlock( &b->b_mutex );
- b = next;
- *res = LDAP_BUSY;
- continue;
- }
-
- if ( op->o_tag == LDAP_REQ_BIND
-#ifdef LDAP_API_FEATURE_VERIFY_CREDENTIALS
- && !(lload_features & LLOAD_FEATURE_VC)
-#endif /* LDAP_API_FEATURE_VERIFY_CREDENTIALS */
- ) {
- head = &b->b_bindconns;
- } else {
- head = &b->b_conns;
- }
- if ( !LDAP_CIRCLEQ_EMPTY( head ) ) {
- *res = LDAP_BUSY;
- }
+ rc = backend_select( b, op, cp, res, message );
+ checked_unlock( &b->b_mutex );
- LDAP_CIRCLEQ_FOREACH ( c, head, c_next ) {
- checked_lock( &c->c_io_mutex );
- CONNECTION_LOCK(c);
- if ( c->c_state == LLOAD_C_READY && !c->c_pendingber &&
- ( b->b_max_conn_pending == 0 ||
- c->c_n_ops_executing < b->b_max_conn_pending ) ) {
- Debug( LDAP_DEBUG_CONNS, "backend_select: "
- "selected connection connid=%lu for client "
- "connid=%lu msgid=%d\n",
- c->c_connid, op->o_client_connid, op->o_client_msgid );
-
- /* c_state is DYING if we're about to be unlinked */
- assert( IS_ALIVE( c, c_live ) );
-
- /*
- * Round-robin step:
- * Rotate the queue to put this connection at the end, same for
- * the backend.
- */
- LDAP_CIRCLEQ_MAKE_TAIL( head, c, c_next );
-
- checked_lock( &backend_mutex );
- current_backend = next;
- checked_unlock( &backend_mutex );
-
- b->b_n_ops_executing++;
- if ( op->o_tag == LDAP_REQ_BIND ) {
- b->b_counters[LLOAD_STATS_OPS_BIND].lc_ops_received++;
- } else {
- b->b_counters[LLOAD_STATS_OPS_OTHER].lc_ops_received++;
- }
- c->c_n_ops_executing++;
- c->c_counters.lc_ops_received++;
-
- checked_unlock( &b->b_mutex );
- *res = LDAP_SUCCESS;
- CONNECTION_ASSERT_LOCKED(c);
- assert_locked( &c->c_io_mutex );
- return c;
- }
- CONNECTION_UNLOCK(c);
- checked_unlock( &c->c_io_mutex );
+ if ( rc && *cp ) {
+ /*
+ * Round-robin step:
+ * Rotate the queue to put this backend at the end. The race here
+ * is acceptable.
+ */
+ checked_lock( &backend_mutex );
+ current_backend = next;
+ checked_unlock( &backend_mutex );
+ return rc;
}
- checked_unlock( &b->b_mutex );
b = next;
} while ( b != first );
- return NULL;
+ return rc;
}
/*
ber_int_t version;
ber_tag_t tag;
unsigned long pin;
- int res, rc = LDAP_SUCCESS;
+ int res = LDAP_UNAVAILABLE, rc = LDAP_SUCCESS;
+ char *message = "no connections available";
CONNECTION_LOCK(client);
pin = client->c_pin_id;
if ( upstream ) {
/* No need to do anything */
} else if ( !pin ) {
- upstream = backend_select( op, &res );
+ upstream_select( op, &upstream, &res, &message );
} else {
Debug( LDAP_DEBUG_STATS, "request_bind: "
"connid=%lu, msgid=%d pinned upstream lost\n",
Debug( LDAP_DEBUG_STATS, "request_bind: "
"connid=%lu, msgid=%d no available connection found\n",
op->o_client_connid, op->o_client_msgid );
- operation_send_reject( op, res, "no connections available", 1 );
+ operation_send_reject( op, res, message, 1 );
assert( client->c_pin_id == 0 );
goto done;
}
request_process( LloadConnection *client, LloadOperation *op )
{
BerElement *output;
- LloadConnection *upstream;
+ LloadConnection *upstream = NULL;
ber_int_t msgid;
- int res, rc = LDAP_SUCCESS;
+ int res = LDAP_UNAVAILABLE, rc = LDAP_SUCCESS;
+ char *message = "no connections available";
- upstream = backend_select( op, &res );
+ upstream_select( op, &upstream, &res, &message );
if ( !upstream ) {
Debug( LDAP_DEBUG_STATS, "request_process: "
"connid=%lu, msgid=%d no available connection found\n",
op->o_client_connid, op->o_client_msgid );
- operation_send_reject( op, res, "no connections available", 1 );
+ operation_send_reject( op, res, message, 1 );
goto fail;
}
CONNECTION_ASSERT_LOCKED(upstream);
projects / thirdparty / openldap.git / commitdiff
