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dcb.h

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-------
Removed DCB states DCB_STATE_IDLE, and DCB_STATE_PROCESSING.
Added DCB_STATE_UNDEFINED for initial content for state variable which doesn't have any specific value set, and DCB_STATE_NOPOLLING to indicate that dcb has been removed from poll set.

Added following dcb roles: DCB_ROLE_SERVICE_LISTENER for listeners of services, and DCB_ROLE_REQUEST_HANDLER for client/backend dcbs. Listeners may have state DCB_STATE_LISTENING, but not DCB_STATE_POLLING. Request handlers may have DCB_STATE_POLLING but not DCB_STATE_LISTENING. Role is passed as an argument to dcb.c:dcb_alloc.

From now on, struct check numbers of DCB are included and checked in DEBUG build only.

Added dcb_role_t dcb_role-member to DCB as well as SPINLOCK dcb_initlock, which protects state changes.

Removed extern keyword from function declarations because functions are by default externally visible if they are declared in header.

dcb.b
------
Function dcb_set_state, and dcb_set_state_nomutex provide functions for changing dcb states. Latter implements a state machine for dcb.
Function dcb_add_to_zombieslist replaces dcb_free. It adds in atomic step dcb to zombieslist and changes state to DCB_STATE_ZOMBIE.
Function dcb_final_free removes dcb from allDCBs list, terminates router and client sessions, and frees dcb and related memory.
Function dcb_process_zombies removes executing thread from dcb's bitmask, and it there are no further thread bits, moves dcb to a victim list, and finally, for each dcb on victim list, closes fd and sets state to DCB_STATE_DISCONNECTED.
Function dcb_close sets dcb state to DCB_STATE_NOPOLLIN, removes dcb from poll set and sets bit to bitmask for each server thread in an atomic step.  

poll.c
------
Function poll_add_dcb sets either DCB_STATE_LISTENING or DCB_STATE_POLLING state for newly created dcb, depending whether the role of dcb is DCB_ROLE_SERVICE_LISTENER, or DCB_ROLE_REQUEST_HANDLER, respectively. Then dcb is set to poll set.

poll_waitevents : commented out code which skipped event if dcb was added to zombieslist or if fd was closed. Added state checks.

service.c : Minor changes.
httpd.c : Removed dcb state changes. They are done in core.
mysql_backend.c : Added checks, removed dcb state changes.
mysql_client.c : Removed dcb state changes. Added checks.
mysql_common.c : Minor changes
telnetd.c : Removed state changes. Replaced some typecasts and pointer references with local variable reads.
skygw_debug.h : Removed two states, and added two to state printing macro.
This commit is contained in:
vraatikka
2013-09-05 22:00:02 +03:00
parent 17ec98fa3d
commit 66e9be814b
10 changed files with 576 additions and 384 deletions
Download Patch File Download Diff File Expand all files Collapse all files

108
server/modules/protocol/mysql_backend.c
View File

@ -146,37 +146,21 @@ static int gw_read_backend_event(DCB *dcb) {
MYSQL_session *current_session = NULL;
int rc = 0;
dcb->state = DCB_STATE_PROCESSING;
CHK_DCB(dcb);
CHK_SESSION(dcb->session);
ss_info_dassert(dcb->session != NULL,
"Backend dcb doesn't have session");
ss_info_dassert(dcb->session->client != NULL,
"Session's client dcb pointer is NULL");
if(dcb->session) {
CHK_SESSION(dcb->session);
if (dcb->session->client == NULL) {
dcb->state = DCB_STATE_DISCONNECTED;
skygw_log_write(
LOGFILE_ERROR,
"%lu [gw_read_backend_event] client dcb is NULL for backend dcb %d.",
pthread_self(),
dcb->fd);
dcb->state = DCB_STATE_DISCONNECTED;
return 1;
}
client_protocol = SESSION_PROTOCOL(dcb->session, MySQLProtocol);
} else {
skygw_log_write(
LOGFILE_ERROR,
"%lu [gw_read_backend_event] dcb->session is NULL for backend dcb %d.",
pthread_self(),
dcb->fd);
dcb->state = DCB_STATE_DISCONNECTED;
return 1;
}
backend_protocol = (MySQLProtocol *) dcb->protocol;
client_protocol = SESSION_PROTOCOL(dcb->session, MySQLProtocol);
backend_protocol = (MySQLProtocol *) dcb->protocol;
/** return only with complete session */
current_session = gw_get_shared_session_auth_info(dcb);
ss_dassert(current_session != NULL);
ss_dassert(dcb->session->state != SESSION_STATE_ALLOC);
/* fprintf(stderr, ">>> backend EPOLLIN from %i, command %i,protocol
* state [%s]\n", dcb->fd, dcb->command, gw_mysql_protocol_state2string
* (backend_protocol->state));
@ -202,17 +186,18 @@ static int gw_read_backend_event(DCB *dcb) {
/* ready to check the authentication reply from backend */
if (backend_protocol->state == MYSQL_AUTH_RECV) {
ROUTER_OBJECT *router = NULL;
ROUTER_OBJECT *router = NULL;
ROUTER *router_instance = NULL;
void *rsession = NULL;
int rv = -1;
SESSION *session = dcb->session;
if (session) {
router = session->service->router;
router_instance = session->service->router_instance;
rsession = session->router_session;
}
CHK_SESSION(session);
router = session->service->router;
router_instance = session->service->router_instance;
rsession = session->router_session;
/* read backed auth reply */
rv = gw_receive_backend_auth(backend_protocol);
@ -222,12 +207,17 @@ static int gw_read_backend_event(DCB *dcb) {
LOGFILE_ERROR,
"%lu [gw_read_backend_event] caught "
"MYSQL_FAILED_AUTHENTICATION from "
"gw_receive_backend_auth. Fd %d, user %s.",
"gw_receive_backend_auth. Fd %d, "
"user %s.",
pthread_self(),
dcb->fd,
current_session->user);
backend_protocol->state = MYSQL_AUTH_FAILED;
#if 0
ss_dassert(backend_protocol->state !=
MYSQL_AUTH_FAILED);
#endif
/* send an error to the client */
mysql_send_custom_error(
dcb->session->client,
@ -245,17 +235,19 @@ static int gw_read_backend_event(DCB *dcb) {
if (rsession != NULL) {
skygw_log_write_flush(
LOGFILE_TRACE,
"%lu [gw_read_backend_event] Call "
"closeSession for backend session.",
"%lu [gw_read_backend_event] "
"Call closeSession for backend "
"session.",
pthread_self());
/* close the active session */
router->closeSession(router_instance, rsession);
router->closeSession(router_instance,
rsession);
} else {
skygw_log_write(
LOGFILE_TRACE,
"%lu [gw_read_backend_event] "
"closeSession already called for "
"backend session.",
"closeSession already called "
"for backend session.",
pthread_self());
}
rc = 1;
@ -266,7 +258,8 @@ static int gw_read_backend_event(DCB *dcb) {
LOGFILE_TRACE,
"%lu [gw_read_backend_event] caught "
"MYSQL_SUCCESFUL_AUTHENTICATION from "
"gw_receive_backend_auth. Fd %d, user %s.",
"gw_receive_backend_auth. Fd %d, "
"user %s.",
pthread_self(),
dcb->fd,
current_session->user);
@ -276,7 +269,6 @@ static int gw_read_backend_event(DCB *dcb) {
/* check the delay queue and flush the data */
if(dcb->delayq) {
backend_write_delayqueue(dcb);
dcb->state = DCB_STATE_POLLING;
spinlock_release(&dcb->authlock);
rc = 1;
goto return_rc;
@ -304,6 +296,7 @@ static int gw_read_backend_event(DCB *dcb) {
void *rsession = NULL;
SESSION *session = dcb->session;
CHK_SESSION(session);
/* read available backend data */
rc = dcb_read(dcb, &head);
@ -312,26 +305,22 @@ static int gw_read_backend_event(DCB *dcb) {
goto return_rc;
}
if (session != NULL) {
router = session->service->router;
router_instance = session->service->router_instance;
rsession = session->router_session;
}
router = session->service->router;
router_instance = session->service->router_instance;
rsession = session->router_session;
/* Note the gwbuf doesn't have here a valid queue->command
* descriptions as it is a fresh new one!
* We only have the copied value in dcb->command from previuos func.write()
* and this will be used by the router->clientReply
* We only have the copied value in dcb->command from
* previuos func.write() and this will be used by the
* router->clientReply
* and pass now the gwbuf to the router
*/
/* and pass now the gwbuf to the router */
router->clientReply(router_instance, rsession, head, dcb);
rc = 1;
goto return_rc;
}
rc = 0;
return_rc:
dcb->state = DCB_STATE_POLLING;
return rc;
}
@ -347,18 +336,16 @@ static int gw_write_backend_event(DCB *dcb) {
//fprintf(stderr, ">>> backend EPOLLOUT %i, protocol state [%s]\n", backend_protocol->fd, gw_mysql_protocol_state2string(backend_protocol->state));
// spinlock_acquire(&dcb->connectlock);
dcb->state = DCB_STATE_PROCESSING;
/**
* vraa: what is the logic in this?
*/
if (backend_protocol->state == MYSQL_PENDING_CONNECT) {
backend_protocol->state = MYSQL_CONNECTED;
backend_protocol->state = MYSQL_CONNECTED;
// spinlock_release(&dcb->connectlock);
dcb->state = DCB_STATE_POLLING;
return 1;
}
// spinlock_release(&dcb->connectlock);
dcb_drain_writeq(dcb);
dcb->state = DCB_STATE_POLLING;
return 1;
}
@ -456,7 +443,8 @@ static int gw_create_backend_connection(
skygw_log_write(
LOGFILE_TRACE,
"%lu [gw_create_backend_connection] Established "
"connection to %s:%i, backend fd %d client fd %d.",
"connection to %s:%i, backend fd %d client "
"fd %d.",
pthread_self(),
server->name,
server->port,
@ -492,8 +480,6 @@ static int gw_create_backend_connection(
session->client->fd);
break;
} /**< switch */
backend_dcb->state = DCB_STATE_POLLING;
return_fd:
ss_dassert(backend_dcb->fd == fd);
ss_dassert(backend_dcb->fd == protocol->fd);
@ -547,7 +533,6 @@ static void backend_set_delayqueue(DCB *dcb, GWBUF *queue) {
dcb->delayq = queue;
}
}
spinlock_release(&dcb->delayqlock);
}
@ -681,4 +666,3 @@ static int gw_session(DCB *backend_dcb, void *data) {
return 0;
}
/////