/* * 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)#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 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(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 */	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"); 	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);	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;	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	 */	if ((clnt = host->h_rpcclnt) != NULL) {		xprt = clnt->cl_xprt;		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 {		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);		xprt->resvport = 1;	/* NLM requires a reserved port */ 		/* Existing NLM servers accept AUTH_UNIX only */		clnt = rpc_new_client(xprt, host->h_name, &nlm_program,					host->h_version, RPC_AUTH_UNIX);		if (IS_ERR(clnt))			goto forgetit;		clnt->cl_autobind = 1;	/* turn on pmap queries */		clnt->cl_softrtry = 1; /* All queries are soft */ 		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 */voidnlm_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));		}	}} /* * Shut down the hosts module. * Note that this routine is called only at server shutdown time. */voidnlm_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 voidnlm_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);				}			}			kfree(host);			nrhosts--;		}	} 	next_gc = jiffies + NLM_HOST_COLLECT;}