haproxy/include/proto/queue.h
Willy Tarreau 80b286a064 [BUG] do not dequeue requests on a dead server
Kai Krueger reported a problem when a server goes down with active
connections. A lot of connections were drained by that server. Kai
did an amazing job at tracking this bug down to the dequeuing
mechanism which forgets to check the server state before allowing
a request to be sent to a server.

The problem occurs more often with long requests, which have a chance
to complete after the server is completely marked down, and to find
requests in the global queue which have not yet been fetched by other
servers.

The fix consists in ensuring that a server is up before sending it
any new request from the queue.
2008-11-30 21:51:58 +01:00

83 lines
2.4 KiB
C

/*
include/proto/queue.h
This file defines everything related to queues.
Copyright (C) 2000-2008 Willy Tarreau - w@1wt.eu
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation, version 2.1
exclusively.
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#ifndef _PROTO_QUEUE_H
#define _PROTO_QUEUE_H
#include <common/config.h>
#include <common/memory.h>
#include <common/mini-clist.h>
#include <types/proxy.h>
#include <types/queue.h>
#include <types/session.h>
#include <types/server.h>
#include <types/task.h>
extern struct pool_head *pool2_pendconn;
int init_pendconn();
struct session *pendconn_get_next_sess(struct server *srv, struct proxy *px);
struct pendconn *pendconn_add(struct session *sess);
void pendconn_free(struct pendconn *p);
void process_srv_queue(struct server *s);
unsigned int srv_dynamic_maxconn(const struct server *s);
/* Returns the first pending connection for server <s>, which may be NULL if
* nothing is pending.
*/
static inline struct pendconn *pendconn_from_srv(const struct server *s) {
if (!s->nbpend)
return NULL;
return LIST_ELEM(s->pendconns.n, struct pendconn *, list);
}
/* Returns the first pending connection for proxy <px>, which may be NULL if
* nothing is pending.
*/
static inline struct pendconn *pendconn_from_px(const struct proxy *px) {
if (!px->nbpend)
return NULL;
return LIST_ELEM(px->pendconns.n, struct pendconn *, list);
}
/* returns 0 if nothing has to be done for server <s> regarding queued connections,
* and non-zero otherwise. If the server is down, we always return zero. Suited for
* and if/else usage.
*/
static inline int may_dequeue_tasks(const struct server *s, const struct proxy *p) {
return (s && (s->state & SRV_RUNNING) && (s->nbpend || p->nbpend) &&
(!s->maxconn || s->cur_sess < srv_dynamic_maxconn(s)));
}
#endif /* _PROTO_QUEUE_H */
/*
* Local variables:
* c-indent-level: 8
* c-basic-offset: 8
* End:
*/