linux/fs/lockd/host.c

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/*
* 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>
#include <linux/mutex.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)
static struct nlm_host * nlm_hosts[NLM_HOST_NRHASH];
static unsigned long next_gc;
static int nrhosts;
static DEFINE_MUTEX(nlm_host_mutex);
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(const struct sockaddr_in *sin, int proto, int version,
const char *hostname, int hostname_len)
{
return nlm_lookup_host(0, sin, proto, version,
hostname, hostname_len);
}
/*
* Find an NLM client handle in the cache. If there is none, create it.
*/
struct nlm_host *
nlmsvc_lookup_host(struct svc_rqst *rqstp,
const char *hostname, int hostname_len)
{
return nlm_lookup_host(1, &rqstp->rq_addr,
rqstp->rq_prot, rqstp->rq_vers,
hostname, hostname_len);
}
/*
* Common host lookup routine for server & client
*/
struct nlm_host *
nlm_lookup_host(int server, const struct sockaddr_in *sin,
int proto, int version,
const char *hostname,
int hostname_len)
{
struct nlm_host *host, **hp;
u32 addr;
int hash;
dprintk("lockd: nlm_lookup_host(%u.%u.%u.%u, p=%d, v=%d, my role=%s, name=%.*s)\n",
NIPQUAD(sin->sin_addr.s_addr), proto, version,
server? "server" : "client",
hostname_len,
hostname? hostname : "<none>");
hash = NLM_ADDRHASH(sin->sin_addr.s_addr);
/* Lock hash table */
mutex_lock(&nlm_host_mutex);
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);
mutex_unlock(&nlm_host_mutex);
return host;
}
}
/* Ooops, no host found, create it */
dprintk("lockd: creating host entry\n");
host = kzalloc(sizeof(*host), GFP_KERNEL);
if (!host)
goto nohost;
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;
mutex_init(&host->h_mutex);
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);
init_rwsem(&host->h_rwsem);
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);
INIT_LIST_HEAD(&host->h_granted);
INIT_LIST_HEAD(&host->h_reclaim);
if (++nrhosts > NLM_HOST_MAX)
next_gc = 0;
nohost:
mutex_unlock(&nlm_host_mutex);
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;
mutex_lock(&nlm_host_mutex);
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);
mutex_unlock(&nlm_host_mutex);
return host;
}
}
}
mutex_unlock(&nlm_host_mutex);
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;
dprintk("lockd: nlm_bind_host(%08x)\n",
(unsigned)ntohl(host->h_addr.sin_addr.s_addr));
/* Lock host handle */
mutex_lock(&host->h_mutex);
/* If we've already created an RPC client, check whether
* RPC rebind is required
*/
if ((clnt = host->h_rpcclnt) != NULL) {
if (time_after_eq(jiffies, host->h_nextrebind)) {
rpc_force_rebind(clnt);
host->h_nextrebind = jiffies + NLM_HOST_REBIND;
dprintk("lockd: next rebind in %ld jiffies\n",
host->h_nextrebind - jiffies);
}
} else {
unsigned long increment = nlmsvc_timeout * HZ;
struct rpc_timeout timeparms = {
.to_initval = increment,
.to_increment = increment,
.to_maxval = increment * 6UL,
.to_retries = 5U,
};
struct rpc_create_args args = {
.protocol = host->h_proto,
.address = (struct sockaddr *)&host->h_addr,
.addrsize = sizeof(host->h_addr),
.timeout = &timeparms,
.servername = host->h_name,
.program = &nlm_program,
.version = host->h_version,
.authflavor = RPC_AUTH_UNIX,
.flags = (RPC_CLNT_CREATE_HARDRTRY |
RPC_CLNT_CREATE_AUTOBIND),
};
clnt = rpc_create(&args);
if (!IS_ERR(clnt))
host->h_rpcclnt = clnt;
else {
printk("lockd: couldn't create RPC handle for %s\n", host->h_name);
clnt = NULL;
}
}
mutex_unlock(&host->h_mutex);
return clnt;
}
/*
* 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)) {
rpc_force_rebind(host->h_rpcclnt);
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);
BUG_ON(atomic_read(&host->h_count) < 0);
if (atomic_dec_and_test(&host->h_count)) {
BUG_ON(!list_empty(&host->h_lockowners));
BUG_ON(!list_empty(&host->h_granted));
BUG_ON(!list_empty(&host->h_reclaim));
}
}
}
/*
* We were notified that the host indicated by address &sin
* has rebooted.
* Release all resources held by that peer.
*/
void nlm_host_rebooted(const struct sockaddr_in *sin, const struct nlm_reboot *argp)
{
struct nlm_host *host;
int server;
/* Obtain the host pointer for this NFS server and try to
* reclaim all locks we hold on this server.
*/
server = (argp->proto & 1)? 1 : 0;
host = nlm_lookup_host(server, sin, argp->proto >> 1, argp->vers,
argp->mon, argp->len);
if (host == NULL)
return;
if (server == 0) {
/* We are client, he's the server: try to reclaim all locks. */
nlmclnt_recovery(host, argp->state);
} else {
/* He's the client, we're the server: delete all locks held by the client */
nlmsvc_free_host_resources(host);
}
nlm_release_host(host);
}
/*
* 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");
mutex_lock(&nlm_host_mutex);
/* 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();
mutex_unlock(&nlm_host_mutex);
/* 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;
/*
* Unmonitor unless host was invalidated (i.e. lockd restarted)
*/
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);
}
}
kfree(host);
nrhosts--;
}
}
next_gc = jiffies + NLM_HOST_COLLECT;
}