fs/lockd/host.c - maze/linux - Git at Google

 /*
  * 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;
 	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;
 	struct rpc_xprt	*xprt;

 	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) {
 		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;
 	}

 	mutex_unlock(&host->h_mutex);
 	return clnt;

 forgetit:
 	printk("lockd: couldn't create RPC handle for %s\n", host->h_name);
 	mutex_unlock(&host->h_mutex);
 	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)) {
 		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.
  */
 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;
 			/* 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;
 }
	/*
	* 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;
	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;
	struct rpc_xprt *xprt;

	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) {
	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;
	}

	mutex_unlock(&host->h_mutex);
	return clnt;

	forgetit:
	printk("lockd: couldn't create RPC handle for %s\n", host->h_name);
	mutex_unlock(&host->h_mutex);
	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)) {
	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.
	*/
	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;
	/* 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;
	}