r1919 - trunk/varnish-cache/bin/varnishd
phk at projects.linpro.no
phk at projects.linpro.no
Tue Aug 21 20:59:35 CEST 2007
Author: phk
Date: 2007-08-21 20:59:35 +0200 (Tue, 21 Aug 2007)
New Revision: 1919
Modified:
trunk/varnish-cache/bin/varnishd/cache_backend_simple.c
trunk/varnish-cache/bin/varnishd/cache_fetch.c
Log:
Almost total rewrite, but same functionality, hopefully less the races
in ticket #144.
Use per backend mutex, do refcounts right, protect the address structures
with a sequence number.
Should close #144.
Modified: trunk/varnish-cache/bin/varnishd/cache_backend_simple.c
===================================================================
--- trunk/varnish-cache/bin/varnishd/cache_backend_simple.c 2007-08-21 18:57:14 UTC (rev 1918)
+++ trunk/varnish-cache/bin/varnishd/cache_backend_simple.c 2007-08-21 18:59:35 UTC (rev 1919)
@@ -49,10 +49,6 @@
#include "cache.h"
#include "vrt.h"
-static TAILQ_HEAD(,vbe_conn) vbe_head = TAILQ_HEAD_INITIALIZER(vbe_head);
-
-static MTX besmtx;
-
struct bes {
unsigned magic;
#define BES_MAGIC 0x015e17ac
@@ -62,42 +58,100 @@
struct addrinfo *last_addr;
double dnsttl;
double dnstime;
+ unsigned dnsseq;
TAILQ_HEAD(, vbe_conn) connlist;
};
/*--------------------------------------------------------------------*/
-static struct vbe_conn *
-bes_new_conn(void)
+
+static int
+bes_conn_try_list(struct sess *sp, struct bes *bes)
{
- struct vbe_conn *vbc;
+ struct addrinfo *ai, *from;
+ struct sockaddr_storage ss;
+ int fam, sockt, proto;
+ socklen_t alen;
+ int s, loops;
+ char abuf1[TCP_ADDRBUFSIZE], abuf2[TCP_ADDRBUFSIZE];
+ char pbuf1[TCP_PORTBUFSIZE], pbuf2[TCP_PORTBUFSIZE];
+ unsigned myseq;
- vbc = calloc(sizeof *vbc, 1);
- if (vbc == NULL)
- return (NULL);
- VSL_stats->n_vbe_conn++;
- vbc->magic = VBE_CONN_MAGIC;
- vbc->fd = -1;
- return (vbc);
+ /* Called with lock held */
+ myseq = bes->dnsseq;
+ loops = 0;
+ from = bes->last_addr;
+ for (ai = from; ai != NULL && (loops != 1 || ai != from);) {
+ fam = ai->ai_family;
+ sockt = ai->ai_socktype;
+ proto = ai->ai_protocol;
+ alen = ai->ai_addrlen;
+ assert(alen <= sizeof ss);
+ memcpy(&ss, ai->ai_addr, alen);
+ UNLOCK(&sp->backend->mtx);
+ s = socket(fam, sockt, proto);
+ if (s >= 0 && connect(s, (void *)&ss, alen)) {
+ AZ(close(s));
+ s = -1;
+ }
+ if (s >= 0) {
+ TCP_myname(s, abuf1, sizeof abuf1, pbuf1, sizeof pbuf1);
+ TCP_name((void*)&ss, alen,
+ abuf2, sizeof abuf2, pbuf2, sizeof pbuf2);
+ WSL(sp->wrk, SLT_BackendOpen, s, "%s %s %s %s %s",
+ sp->backend->vcl_name, abuf1, pbuf1, abuf2, pbuf2);
+ }
+ LOCK(&sp->backend->mtx);
+ if (s >= 0) {
+ if (myseq == bes->dnsseq)
+ bes->last_addr = ai;
+ return (s);
+ }
+ if (myseq != bes->dnsseq) {
+ loops = 0;
+ from = bes->last_addr;
+ ai = from;
+ } else {
+ ai = ai->ai_next;
+ if (ai == NULL) {
+ loops++;
+ ai = bes->addr;
+ }
+ }
+ }
+ return (-1);
}
-/*--------------------------------------------------------------------
- * XXX: There is a race here, we need to lock the replacement of the
- * XXX: resolved addresses, or some other thread might try to access
- * XXX: them while/during/after we changed them.
- * XXX: preferably, we should make a copy to the vbe while we hold a
- * XXX: lock anyway.
- */
+/*--------------------------------------------------------------------*/
-static void
-bes_lookup(struct backend *bp)
+static int
+bes_conn_try(struct sess *sp, struct backend *bp)
{
+ int s;
+ struct bes *bes;
struct addrinfo *res, hint, *old;
int error;
- struct bes *bes;
CAST_OBJ_NOTNULL(bes, bp->priv, BES_MAGIC);
+ LOCK(&bp->mtx);
+
+ s = bes_conn_try_list(sp, bes);
+ if (s >= 0) {
+ bp->refcount++;
+ UNLOCK(&bp->mtx);
+ return (s);
+ }
+
+ if (bes->dnstime + bes->dnsttl >= TIM_mono()) {
+ UNLOCK(&bp->mtx);
+ return (-1);
+ }
+
+ /* Then do another lookup to catch DNS changes */
+ bes->dnstime = TIM_mono();
+ UNLOCK(&bp->mtx);
+
memset(&hint, 0, sizeof hint);
hint.ai_family = PF_UNSPEC;
hint.ai_socktype = SOCK_STREAM;
@@ -105,111 +159,33 @@
error = getaddrinfo(bes->hostname,
bes->portname == NULL ? "http" : bes->portname,
&hint, &res);
- bes->dnstime = TIM_mono();
if (error) {
if (res != NULL)
freeaddrinfo(res);
printf("getaddrinfo: %s\n", gai_strerror(error)); /* XXX */
- return;
+ LOCK(&bp->mtx);
+ } else {
+ LOCK(&bp->mtx);
+ bes->dnsseq++;
+ old = bes->addr;
+ bes->last_addr = res;
+ bes->addr = res;
+ if (old != NULL)
+ freeaddrinfo(old);
}
- old = bes->addr;
- bes->last_addr = res;
- bes->addr = res;
- if (old != NULL)
- freeaddrinfo(old);
-}
-/*--------------------------------------------------------------------*/
-
-static int
-bes_sock_conn(const struct addrinfo *ai)
-{
- int s;
-
- s = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
- if (s >= 0 && connect(s, ai->ai_addr, ai->ai_addrlen)) {
- AZ(close(s));
- s = -1;
- }
- return (s);
-}
-
-/*--------------------------------------------------------------------*/
-
-static int
-bes_conn_try(struct backend *bp, struct addrinfo **pai)
-{
- struct addrinfo *ai;
- int s;
- struct bes *bes;
-
- CAST_OBJ_NOTNULL(bes, bp->priv, BES_MAGIC);
-
- /* First try the cached good address, and any following it */
- for (ai = bes->last_addr; ai != NULL; ai = ai->ai_next) {
- s = bes_sock_conn(ai);
- if (s >= 0) {
- bes->last_addr = ai;
- *pai = ai;
- return (s);
- }
- }
-
- /* Then try the list until the cached last good address */
- for (ai = bes->addr; ai != bes->last_addr; ai = ai->ai_next) {
- s = bes_sock_conn(ai);
- if (s >= 0) {
- bes->last_addr = ai;
- *pai = ai;
- return (s);
- }
- }
-
- if (bes->dnstime + bes->dnsttl >= TIM_mono())
- return (-1);
-
- /* Then do another lookup to catch DNS changes */
- bes_lookup(bp);
-
/* And try the entire list */
- for (ai = bes->addr; ai != NULL; ai = ai->ai_next) {
- s = bes_sock_conn(ai);
- if (s >= 0) {
- bes->last_addr = ai;
- *pai = ai;
- return (s);
- }
+ s = bes_conn_try_list(sp, bes);
+ if (s >= 0) {
+ bp->refcount++;
+ UNLOCK(&bp->mtx);
+ return (s);
}
+ UNLOCK(&bp->mtx);
return (-1);
}
-static int
-bes_connect(struct sess *sp, struct backend *bp)
-{
- int s;
- char abuf1[TCP_ADDRBUFSIZE], abuf2[TCP_ADDRBUFSIZE];
- char pbuf1[TCP_PORTBUFSIZE], pbuf2[TCP_PORTBUFSIZE];
- struct addrinfo *ai;
- struct bes *bes;
-
-
- CHECK_OBJ_NOTNULL(bp, BACKEND_MAGIC);
- CAST_OBJ_NOTNULL(bes, bp->priv, BES_MAGIC);
- AN(bes->hostname);
-
- s = bes_conn_try(bp, &ai);
- if (s < 0)
- return (s);
-
- TCP_myname(s, abuf1, sizeof abuf1, pbuf1, sizeof pbuf1);
- TCP_name(ai->ai_addr, ai->ai_addrlen,
- abuf2, sizeof abuf2, pbuf2, sizeof pbuf2);
- WSL(sp->wrk, SLT_BackendOpen, s, "%s %s %s %s %s",
- bp->vcl_name, abuf1, pbuf1, abuf2, pbuf2);
- return (s);
-}
-
/* Get a backend connection ------------------------------------------
*
* Try all cached backend connections for this backend, and use the
@@ -223,32 +199,26 @@
static struct vbe_conn *
bes_nextfd(struct sess *sp)
{
- struct vbe_conn *vc, *vc2;
+ struct vbe_conn *vc;
struct pollfd pfd;
struct backend *bp;
int reuse = 0;
struct bes *bes;
CHECK_OBJ_NOTNULL(sp, SESS_MAGIC);
+ CHECK_OBJ_NOTNULL(sp->backend, BACKEND_MAGIC);
bp = sp->backend;
- CHECK_OBJ_NOTNULL(bp, BACKEND_MAGIC);
CAST_OBJ_NOTNULL(bes, bp->priv, BES_MAGIC);
- vc2 = NULL;
while (1) {
- LOCK(&besmtx);
+ LOCK(&bp->mtx);
vc = TAILQ_FIRST(&bes->connlist);
if (vc != NULL) {
+ bp->refcount++;
assert(vc->backend == bp);
assert(vc->fd >= 0);
TAILQ_REMOVE(&bes->connlist, vc, list);
- } else {
- vc2 = TAILQ_FIRST(&vbe_head);
- if (vc2 != NULL) {
- VSL_stats->backend_unused--;
- TAILQ_REMOVE(&vbe_head, vc2, list);
- }
}
- UNLOCK(&besmtx);
+ UNLOCK(&bp->mtx);
if (vc == NULL)
break;
@@ -257,45 +227,25 @@
pfd.events = POLLIN;
pfd.revents = 0;
if (!poll(&pfd, 1, 0)) {
- reuse = 1;
- break;
+ /* XXX locking of stats */
+ VSL_stats->backend_reuse += reuse;
+ VSL_stats->backend_conn++;
+ return (vc);
}
VBE_ClosedFd(sp->wrk, vc);
}
- if (vc == NULL) {
- if (vc2 == NULL)
- vc = bes_new_conn();
- else
- vc = vc2;
- if (vc != NULL) {
- assert(vc->fd == -1);
- AZ(vc->backend);
- vc->fd = bes_connect(sp, bp);
- if (vc->fd < 0) {
- LOCK(&besmtx);
- TAILQ_INSERT_HEAD(&vbe_head, vc, list);
- VSL_stats->backend_unused++;
- UNLOCK(&besmtx);
- vc = NULL;
- } else {
- vc->backend = bp;
- }
- }
- }
- LOCK(&besmtx);
- if (vc != NULL ) {
- VSL_stats->backend_reuse += reuse;
- VSL_stats->backend_conn++;
- } else {
+ vc = VBE_NewConn();
+ assert(vc->fd == -1);
+ AZ(vc->backend);
+ vc->fd = bes_conn_try(sp, bp);
+ if (vc->fd < 0) {
+ VBE_ReleaseConn(vc);
VSL_stats->backend_fail++;
- }
- UNLOCK(&besmtx);
- if (vc != NULL ) {
- WSL(sp->wrk, SLT_BackendXID, vc->fd, "%u", sp->xid);
- assert(vc->fd >= 0);
- assert(vc->backend == bp);
- }
+ return (NULL);
+ }
+ vc->backend = bp;
+ VSL_stats->backend_conn++;
return (vc);
}
@@ -306,15 +256,18 @@
{
struct vbe_conn *vc;
unsigned n;
-
for (n = 1; n < 5; n++) {
vc = bes_nextfd(sp);
- if (vc != NULL) {
- WSL(sp->wrk, SLT_Backend, sp->fd, "%d %s", vc->fd,
- sp->backend->vcl_name);
- return (vc);
+ if (vc == NULL) {
+ usleep(100000 * n);
+ continue;
}
- usleep(100000 * n);
+ assert(vc->fd >= 0);
+ assert(vc->backend == sp->backend);
+ WSL(sp->wrk, SLT_BackendXID, vc->fd, "%u", sp->xid);
+ WSL(sp->wrk, SLT_Backend, sp->fd, "%d %s", vc->fd,
+ sp->backend->vcl_name);
+ return (vc);
}
return (NULL);
}
@@ -326,16 +279,14 @@
{
CHECK_OBJ_NOTNULL(vc, VBE_CONN_MAGIC);
+ CHECK_OBJ_NOTNULL(vc->backend, BACKEND_MAGIC);
assert(vc->fd >= 0);
- AN(vc->backend);
WSL(w, SLT_BackendClose, vc->fd, "%s", vc->backend->vcl_name);
AZ(close(vc->fd));
vc->fd = -1;
+ VBE_DropRef(vc->backend);
vc->backend = NULL;
- LOCK(&besmtx);
- TAILQ_INSERT_HEAD(&vbe_head, vc, list);
- VSL_stats->backend_unused++;
- UNLOCK(&besmtx);
+ VBE_ReleaseConn(vc);
}
/* Recycle a connection ----------------------------------------------*/
@@ -350,12 +301,11 @@
CAST_OBJ_NOTNULL(bes, vc->backend->priv, BES_MAGIC);
assert(vc->fd >= 0);
- AN(vc->backend);
WSL(w, SLT_BackendReuse, vc->fd, "%s", vc->backend->vcl_name);
- LOCK(&besmtx);
+ LOCK(&vc->backend->mtx);
VSL_stats->backend_recycle++;
TAILQ_INSERT_HEAD(&bes->connlist, vc, list);
- UNLOCK(&besmtx);
+ VBE_DropRefLocked(vc->backend);
}
/*--------------------------------------------------------------------*/
@@ -366,6 +316,7 @@
struct bes *bes;
struct vbe_conn *vbe;
+ assert(b->refcount == 0);
CAST_OBJ_NOTNULL(bes, b->priv, BES_MAGIC);
free(bes->portname);
free(bes->hostname);
@@ -400,7 +351,6 @@
bes_Init(void)
{
- MTX_INIT(&besmtx);
}
/*--------------------------------------------------------------------*/
Modified: trunk/varnish-cache/bin/varnishd/cache_fetch.c
===================================================================
--- trunk/varnish-cache/bin/varnishd/cache_fetch.c 2007-08-21 18:57:14 UTC (rev 1918)
+++ trunk/varnish-cache/bin/varnishd/cache_fetch.c 2007-08-21 18:59:35 UTC (rev 1919)
@@ -276,11 +276,14 @@
sp->obj->xid = sp->xid;
+ CHECK_OBJ_NOTNULL(sp->backend, BACKEND_MAGIC);
vc = VBE_GetFd(sp);
+ CHECK_OBJ_NOTNULL(sp->backend, BACKEND_MAGIC);
if (vc == NULL)
return (1);
WRK_Reset(w, &vc->fd);
http_Write(w, hp, 0);
+ CHECK_OBJ_NOTNULL(sp->backend, BACKEND_MAGIC);
if (WRK_Flush(w)) {
/* XXX: cleanup */
@@ -294,6 +297,7 @@
CHECK_OBJ_NOTNULL(sp->wrk, WORKER_MAGIC);
CHECK_OBJ_NOTNULL(sp->obj, OBJECT_MAGIC);
+ CHECK_OBJ_NOTNULL(sp->backend, BACKEND_MAGIC);
if (http_RecvHead(hp, vc->fd)) {
/* XXX: cleanup */
return (1);
@@ -302,6 +306,7 @@
/* XXX: cleanup */
return (1);
}
+ CHECK_OBJ_NOTNULL(sp->backend, BACKEND_MAGIC);
CHECK_OBJ_NOTNULL(sp, SESS_MAGIC);
CHECK_OBJ_NOTNULL(sp->wrk, WORKER_MAGIC);
@@ -311,23 +316,28 @@
assert(sp->obj->busy != 0);
+ CHECK_OBJ_NOTNULL(sp->backend, BACKEND_MAGIC);
if (http_GetHdr(hp, H_Last_Modified, &b))
sp->obj->last_modified = TIM_parse(b);
+ CHECK_OBJ_NOTNULL(sp->backend, BACKEND_MAGIC);
/* Filter into object */
hp2 = &sp->obj->http;
len = hp->rx_e - hp->rx_s;
len += 256; /* margin for content-length etc */
+ CHECK_OBJ_NOTNULL(sp->backend, BACKEND_MAGIC);
b = malloc(len);
AN(b);
http_Setup(hp2, b, len);
+ CHECK_OBJ_NOTNULL(sp->backend, BACKEND_MAGIC);
hp2->logtag = HTTP_Obj;
http_CopyResp(hp2, hp);
http_FilterFields(sp->wrk, sp->fd, hp2, hp, HTTPH_A_INS);
http_CopyHome(sp->wrk, sp->fd, hp2);
+ CHECK_OBJ_NOTNULL(sp->backend, BACKEND_MAGIC);
if (body) {
if (http_GetHdr(hp, H_Content_Length, &b))
cls = fetch_straight(sp, vc->fd, hp, b);
@@ -340,6 +350,7 @@
} else
cls = 0;
+ CHECK_OBJ_NOTNULL(sp->backend, BACKEND_MAGIC);
if (cls < 0) {
while (!TAILQ_EMPTY(&sp->obj->store)) {
st = TAILQ_FIRST(&sp->obj->store);
@@ -350,6 +361,7 @@
return (-1);
}
+ CHECK_OBJ_NOTNULL(sp->backend, BACKEND_MAGIC);
{
/* Sanity check fetch methods accounting */
unsigned uu;
@@ -360,13 +372,16 @@
assert(uu == sp->obj->len);
}
+ CHECK_OBJ_NOTNULL(sp->backend, BACKEND_MAGIC);
if (http_GetHdr(hp, H_Connection, &b) && !strcasecmp(b, "close"))
cls = 1;
+ CHECK_OBJ_NOTNULL(sp->backend, BACKEND_MAGIC);
if (cls)
VBE_ClosedFd(sp->wrk, vc);
else
VBE_RecycleFd(sp->wrk, vc);
+ CHECK_OBJ_NOTNULL(sp->backend, BACKEND_MAGIC);
return (0);
}
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