/*
* linux/fs/lockd/host.c
*
* Management for NLM peer hosts. The nlm_host struct is shared
* between client and server implementation. The only reason to
* do so is to reduce code bloat.
*
* Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de>
*/
#include <linux/types.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/in.h>
#include <linux/sunrpc/clnt.h>
#include <linux/sunrpc/svc.h>
#include <linux/lockd/lockd.h>
#include <linux/lockd/sm_inter.h>
#define NLMDBG_FACILITY NLMDBG_HOSTCACHE
#define NLM_HOST_MAX 64
#define NLM_HOST_NRHASH 32
#define NLM_ADDRHASH(addr) (ntohl(addr) & (NLM_HOST_NRHASH-1))
#define NLM_HOST_REBIND (60 * HZ)
#define NLM_HOST_EXPIRE ((nrhosts > NLM_HOST_MAX)? 300 * HZ : 120 * HZ)
#define NLM_HOST_COLLECT ((nrhosts > NLM_HOST_MAX)? 120 * HZ : 60 * HZ)
#define NLM_HOST_ADDR(sv) (&(sv)->s_nlmclnt->cl_xprt->addr)
static struct nlm_host * nlm_hosts[NLM_HOST_NRHASH];
static unsigned long next_gc;
static int nrhosts;
static DECLARE_MUTEX(nlm_host_sema);
static void nlm_gc_hosts(void);
/*
* Find an NLM server handle in the cache. If there is none, create it.
*/
struct nlm_host *
nlmclnt_lookup_host(struct sockaddr_in *sin, int proto, int version)
{
return nlm_lookup_host(0, sin, proto, version);
}
/*
* Find an NLM client handle in the cache. If there is none, create it.
*/
struct nlm_host *
nlmsvc_lookup_host(struct svc_rqst *rqstp)
{
return nlm_lookup_host(1, &rqstp->rq_addr,
rqstp->rq_prot, rqstp->rq_vers);
}
/*
* Common host lookup routine for server & client
*/
struct nlm_host *
nlm_lookup_host(int server, struct sockaddr_in *sin,
int proto, int version)
{
struct nlm_host *host, **hp;
u32 addr;
int hash;
dprintk("lockd: nlm_lookup_host(%08x, p=%d, v=%d)\n",
(unsigned)(sin? ntohl(sin->sin_addr.s_addr) : 0), proto, version);
hash = NLM_ADDRHASH(sin->sin_addr.s_addr);
/* Lock hash table */
down(&nlm_host_sema);
if (time_after_eq(jiffies, next_gc))
nlm_gc_hosts();
for (hp = &nlm_hosts[hash]; (host = *hp) != 0; hp = &host->h_next) {
if (host->h_proto != proto)
continue;
if (host->h_version != version)
continue;
if (host->h_server != server)
continue;
if (nlm_cmp_addr(&host->h_addr, sin)) {
if (hp != nlm_hosts + hash) {
*hp = host->h_next;
host->h_next = nlm_hosts[hash];
nlm_hosts[hash] = host;
}
nlm_get_host(host);
up(&nlm_host_sema);
return host;
}
}
/* Ooops, no host found, create it */
dprintk("lockd: creating host entry\n");
if (!(host = (struct nlm_host *) kmalloc(sizeof(*host), GFP_KERNEL)))
goto nohost;
memset(host, 0, sizeof(*host));
addr = sin->sin_addr.s_addr;
sprintf(host->h_name, "%u.%u.%u.%u", NIPQUAD(addr));
host->h_addr = *sin;
host->h_addr.sin_port = 0; /* ouch! */
host->h_version = version;
host->h_proto = proto;
host->h_rpcclnt = NULL;
init_MUTEX(&host->h_sema);
host->h_nextrebind = jiffies + NLM_HOST_REBIND;
host->h_expires = jiffies + NLM_HOST_EXPIRE;
atomic_set(&host->h_count, 1);
init_waitqueue_head(&host->h_gracewait);
host->h_state = 0; /* pseudo NSM state */
host->h_nsmstate = 0; /* real NSM state */
host->h_server = server;
host->h_next = nlm_hosts[hash];
nlm_hosts[hash] = host;
INIT_LIST_HEAD(&host->h_lockowners);
spin_lock_init(&host->h_lock);
if (++nrhosts > NLM_HOST_MAX)
next_gc = 0;
nohost:
up(&nlm_host_sema);
return host;
}
struct nlm_host *
nlm_find_client(void)
{
/* find a nlm_host for a client for which h_killed == 0.
* and return it
*/
int hash;
down(&nlm_host_sema);
for (hash = 0 ; hash < NLM_HOST_NRHASH; hash++) {
struct nlm_host *host, **hp;
for (hp = &nlm_hosts[hash]; (host = *hp) != 0; hp = &host->h_next) {
if (host->h_server &&
host->h_killed == 0) {
nlm_get_host(host);
up(&nlm_host_sema);
return host;
}
}
}
up(&nlm_host_sema);
return NULL;
}
/*
* Create the NLM RPC client for an NLM peer
*/
struct rpc_clnt *
nlm_bind_host(struct nlm_host *host)
{
struct rpc_clnt *clnt;
struct rpc_xprt *xprt;
dprintk("lockd: nlm_bind_host(%08x)\n",
(unsigned)ntohl(host->h_addr.sin_addr.s_addr));
/* Lock host handle */
down(&host->h_sema);
/* If we've already created an RPC client, check whether
* RPC rebind is required
* Note: why keep rebinding if we're on a tcp connection?
*/
if ((clnt = host->h_rpcclnt) != NULL) {
xprt = clnt->cl_xprt;
if (!xprt->stream && time_after_eq(jiffies, host->h_nextrebind)) {
clnt->cl_port = 0;
host->h_nextrebind = jiffies + NLM_HOST_REBIND;
dprintk("lockd: next rebind in %ld jiffies\n",
host->h_nextrebind - jiffies);
}
} else {
xprt = xprt_create_proto(host->h_proto, &host->h_addr, NULL);
if (IS_ERR(xprt))
goto forgetit;
xprt_set_timeout(&xprt->timeout, 5, nlmsvc_timeout);
/* Existing NLM servers accept AUTH_UNIX only */
clnt = rpc_create_client(xprt, host->h_name, &nlm_program,
host->h_version, RPC_AUTH_UNIX);
if (IS_ERR(clnt)) {
xprt_destroy(xprt);
goto forgetit;
}
clnt->cl_autobind = 1; /* turn on pmap queries */
xprt->nocong = 1; /* No congestion control for NLM */
xprt->resvport = 1; /* NLM requires a reserved port */
host->h_rpcclnt = clnt;
}
up(&host->h_sema);
return clnt;
forgetit:
printk("lockd: couldn't create RPC handle for %s\n", host->h_name);
up(&host->h_sema);
return NULL;
}
/*
* Force a portmap lookup of the remote lockd port
*/
void
nlm_rebind_host(struct nlm_host *host)
{
dprintk("lockd: rebind host %s\n", host->h_name);
if (host->h_rpcclnt && time_after_eq(jiffies, host->h_nextrebind)) {
host->h_rpcclnt->cl_port = 0;
host->h_nextrebind = jiffies + NLM_HOST_REBIND;
}
}
/*
* Increment NLM host count
*/
struct nlm_host * nlm_get_host(struct nlm_host *host)
{
if (host) {
dprintk("lockd: get host %s\n", host->h_name);
atomic_inc(&host->h_count);
host->h_expires = jiffies + NLM_HOST_EXPIRE;
}
return host;
}
/*
* Release NLM host after use
*/
void nlm_release_host(struct nlm_host *host)
{
if (host != NULL) {
dprintk("lockd: release host %s\n", host->h_name);
atomic_dec(&host->h_count);
BUG_ON(atomic_read(&host->h_count) < 0);
}
}
/*
* Shut down the hosts module.
* Note that this routine is called only at server shutdown time.
*/
void
nlm_shutdown_hosts(void)
{
struct nlm_host *host;
int i;
dprintk("lockd: shutting down host module\n");
down(&nlm_host_sema);
/* First, make all hosts eligible for gc */
dprintk("lockd: nuking all hosts...\n");
for (i = 0; i < NLM_HOST_NRHASH; i++) {
for (host = nlm_hosts[i]; host; host = host->h_next)
host->h_expires = jiffies - 1;
}
/* Then, perform a garbage collection pass */
nlm_gc_hosts();
up(&nlm_host_sema);
/* complain if any hosts are left */
if (nrhosts) {
printk(KERN_WARNING "lockd: couldn't shutdown host module!\n");
dprintk("lockd: %d hosts left:\n", nrhosts);
for (i = 0; i < NLM_HOST_NRHASH; i++) {
for (host = nlm_hosts[i]; host; host = host->h_next) {
dprintk(" %s (cnt %d use %d exp %ld)\n",
host->h_name, atomic_read(&host->h_count),
host->h_inuse, host->h_expires);
}
}
}
}
/*
* Garbage collect any unused NLM hosts.
* This GC combines reference counting for async operations with
* mark & sweep for resources held by remote clients.
*/
static void
nlm_gc_hosts(void)
{
struct nlm_host **q, *host;
struct rpc_clnt *clnt;
int i;
dprintk("lockd: host garbage collection\n");
for (i = 0; i < NLM_HOST_NRHASH; i++) {
for (host = nlm_hosts[i]; host; host = host->h_next)
host->h_inuse = 0;
}
/* Mark all hosts that hold locks, blocks or shares */
nlmsvc_mark_resources();
for (i = 0; i < NLM_HOST_NRHASH; i++) {
q = &nlm_hosts[i];
while ((host = *q) != NULL) {
if (atomic_read(&host->h_count) || host->h_inuse
|| time_before(jiffies, host->h_expires)) {
dprintk("nlm_gc_hosts skipping %s (cnt %d use %d exp %ld)\n",
host->h_name, atomic_read(&host->h_count),
host->h_inuse, host->h_expires);
q = &host->h_next;
continue;
}
dprintk("lockd: delete host %s\n", host->h_name);
*q = host->h_next;
/* Don't unmonitor hosts that have been invalidated */
if (host->h_monitored && !host->h_killed)
nsm_unmonitor(host);
if ((clnt = host->h_rpcclnt) != NULL) {
if (atomic_read(&clnt->cl_users)) {
printk(KERN_WARNING
"lockd: active RPC handle\n");
clnt->cl_dead = 1;
} else {
rpc_destroy_client(host->h_rpcclnt);
}
}
BUG_ON(!list_empty(&host->h_lockowners));
kfree(host);
nrhosts--;
}
}
next_gc = jiffies + NLM_HOST_COLLECT;
}
