[deliverable/linux.git] / fs / lockd / host.c

/*
 * 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 hlist_head	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);
static struct nsm_handle *	__nsm_find(const struct sockaddr_in *,
					const char *, int, int);

/*
 * 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 hlist_head *chain;
	struct hlist_node *pos;
	struct nlm_host	*host;
	struct nsm_handle *nsm = NULL;
	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();

	/* We may keep several nlm_host objects for a peer, because each
	 * nlm_host is identified by
	 * (address, protocol, version, server/client)
	 * We could probably simplify this a little by putting all those
	 * different NLM rpc_clients into one single nlm_host object.
	 * This would allow us to have one nlm_host per address.
	 */
	chain = &nlm_hosts[hash];
	hlist_for_each_entry(host, pos, chain, h_hash) {
		if (!nlm_cmp_addr(&host->h_addr, sin))
			continue;

		/* See if we have an NSM handle for this client */
		if (!nsm && (nsm = host->h_nsmhandle) != 0)
			atomic_inc(&nsm->sm_count);

		if (host->h_proto != proto)
			continue;
		if (host->h_version != version)
			continue;
		if (host->h_server != server)
			continue;

		/* Move to head of hash chain. */
		hlist_del(&host->h_hash);
		hlist_add_head(&host->h_hash, chain);

		nlm_get_host(host);
		goto out;
	}

	host = NULL;

	/* Sadly, the host isn't in our hash table yet. See if
	 * we have an NSM handle for it. If not, create one.
	 */
	if (!nsm && !(nsm = nsm_find(sin, hostname, hostname_len)))
		goto out;

	host = kzalloc(sizeof(*host), GFP_KERNEL);
	if (!host) {
		nsm_release(nsm);
		goto out;
	}
	host->h_name	   = nsm->sm_name;
	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_nsmhandle  = nsm;
	host->h_server	   = server;
	hlist_add_head(&host->h_hash, chain);
	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;

out:
	mutex_unlock(&nlm_host_mutex);
	return host;
}

struct nlm_host *
nlm_find_client(void)
{
	struct hlist_head *chain;
	struct hlist_node *pos;

	/* find a nlm_host for a client for which h_killed == 0.
	 * and return it
	 */
	mutex_lock(&nlm_host_mutex);
	for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
		struct nlm_host *host;

		hlist_for_each_entry(host, pos, chain, h_hash) {
			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 char *hostname, int hostname_len,
				u32 new_state)
{
	struct hlist_head *chain;
	struct hlist_node *pos;
	struct nsm_handle *nsm;
	struct nlm_host	*host;

	dprintk("lockd: nlm_host_rebooted(%s, %u.%u.%u.%u)\n",
			hostname, NIPQUAD(sin->sin_addr));

	/* Find the NSM handle for this peer */
	if (!(nsm = __nsm_find(sin, hostname, hostname_len, 0)))
		return;

	/* When reclaiming locks on this peer, make sure that
	 * we set up a new notification */
	nsm->sm_monitored = 0;

	/* Mark all hosts tied to this NSM state as having rebooted.
	 * We run the loop repeatedly, because we drop the host table
	 * lock for this.
	 * To avoid processing a host several times, we match the nsmstate.
	 */
again:	mutex_lock(&nlm_host_mutex);
	for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
		hlist_for_each_entry(host, pos, chain, h_hash) {
			if (host->h_nsmhandle == nsm
			 && host->h_nsmstate != new_state) {
				host->h_nsmstate = new_state;
				host->h_state++;

				nlm_get_host(host);
				mutex_unlock(&nlm_host_mutex);

				if (host->h_server) {
					/* We're server for this guy, just ditch
					 * all the locks he held. */
					nlmsvc_free_host_resources(host);
				} else {
					/* He's the server, initiate lock recovery. */
					nlmclnt_recovery(host);
				}

				nlm_release_host(host);
				goto again;
			}
		}
	}

	mutex_unlock(&nlm_host_mutex);
}

/*
 * Shut down the hosts module.
 * Note that this routine is called only at server shutdown time.
 */
void
nlm_shutdown_hosts(void)
{
	struct hlist_head *chain;
	struct hlist_node *pos;
	struct nlm_host	*host;

	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 (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
		hlist_for_each_entry(host, pos, chain, h_hash)
			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 (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
			hlist_for_each_entry(host, pos, chain, h_hash) {
				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 hlist_head *chain;
	struct hlist_node *pos, *next;
	struct nlm_host	*host;
	struct rpc_clnt	*clnt;

	dprintk("lockd: host garbage collection\n");
	for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
		hlist_for_each_entry(host, pos, chain, h_hash)
			host->h_inuse = 0;
	}

	/* Mark all hosts that hold locks, blocks or shares */
	nlmsvc_mark_resources();

	for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
		hlist_for_each_entry_safe(host, pos, next, chain, h_hash) {
			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);
				continue;
			}
			dprintk("lockd: delete host %s\n", host->h_name);
			hlist_del_init(&host->h_hash);

			/*
			 * 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;
}


/*
 * Manage NSM handles
 */
static LIST_HEAD(nsm_handles);
static DECLARE_MUTEX(nsm_sema);

static struct nsm_handle *
__nsm_find(const struct sockaddr_in *sin,
		const char *hostname, int hostname_len,
		int create)
{
	struct nsm_handle *nsm = NULL;
	struct list_head *pos;

	if (!sin)
		return NULL;

	if (hostname && memchr(hostname, '/', hostname_len) != NULL) {
		if (printk_ratelimit()) {
			printk(KERN_WARNING "Invalid hostname \"%.*s\" "
					    "in NFS lock request\n",
				hostname_len, hostname);
		}
		return NULL;
	}

	down(&nsm_sema);
	list_for_each(pos, &nsm_handles) {
		nsm = list_entry(pos, struct nsm_handle, sm_link);

		if (!nlm_cmp_addr(&nsm->sm_addr, sin))
			continue;
		atomic_inc(&nsm->sm_count);
		goto out;
	}

	if (!create) {
		nsm = NULL;
		goto out;
	}

	nsm = kzalloc(sizeof(*nsm) + hostname_len + 1, GFP_KERNEL);
	if (nsm != NULL) {
		nsm->sm_addr = *sin;
		nsm->sm_name = (char *) (nsm + 1);
		memcpy(nsm->sm_name, hostname, hostname_len);
		nsm->sm_name[hostname_len] = '\0';
		atomic_set(&nsm->sm_count, 1);

		list_add(&nsm->sm_link, &nsm_handles);
	}

out:	up(&nsm_sema);
	return nsm;
}

struct nsm_handle *
nsm_find(const struct sockaddr_in *sin, const char *hostname, int hostname_len)
{
	return __nsm_find(sin, hostname, hostname_len, 1);
}

/*
 * Release an NSM handle
 */
void
nsm_release(struct nsm_handle *nsm)
{
	if (!nsm)
		return;
	if (atomic_dec_and_test(&nsm->sm_count)) {
		down(&nsm_sema);
		if (atomic_read(&nsm->sm_count) == 0) {
			list_del(&nsm->sm_link);
			kfree(nsm);
		}
		up(&nsm_sema);
	}
}
Commit	Line	Data
1da177e4 LT	1	/*
	2	* linux/fs/lockd/host.c
	3	*
	4	* Management for NLM peer hosts. The nlm_host struct is shared
	5	* between client and server implementation. The only reason to
	6	* do so is to reduce code bloat.
	7	*
	8	* Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de>
	9	*/
	10
	11	#include <linux/types.h>
	12	#include <linux/sched.h>
	13	#include <linux/slab.h>
	14	#include <linux/in.h>
	15	#include <linux/sunrpc/clnt.h>
	16	#include <linux/sunrpc/svc.h>
	17	#include <linux/lockd/lockd.h>
	18	#include <linux/lockd/sm_inter.h>
353ab6e9	19	#include <linux/mutex.h>
1da177e4 LT	20
	21
	22	#define NLMDBG_FACILITY NLMDBG_HOSTCACHE
	23	#define NLM_HOST_MAX 64
	24	#define NLM_HOST_NRHASH 32
	25	#define NLM_ADDRHASH(addr) (ntohl(addr) & (NLM_HOST_NRHASH-1))
	26	#define NLM_HOST_REBIND (60 * HZ)
	27	#define NLM_HOST_EXPIRE ((nrhosts > NLM_HOST_MAX)? 300 * HZ : 120 * HZ)
	28	#define NLM_HOST_COLLECT ((nrhosts > NLM_HOST_MAX)? 120 * HZ : 60 * HZ)
1da177e4	29
0cea3276	30	static struct hlist_head nlm_hosts[NLM_HOST_NRHASH];
1da177e4 LT	31	static unsigned long next_gc;
1da177e4 LT	32	static int nrhosts;
353ab6e9	33	static DEFINE_MUTEX(nlm_host_mutex);
1da177e4 LT	34
	35
	36	static void nlm_gc_hosts(void);
8dead0db OK	37	static struct nsm_handle * __nsm_find(const struct sockaddr_in *,
8dead0db OK	38	const char *, int, int);
1da177e4 LT	39
	40	/*
	41	* Find an NLM server handle in the cache. If there is none, create it.
	42	*/
	43	struct nlm_host *
db4e4c9a OK	44	nlmclnt_lookup_host(const struct sockaddr_in *sin, int proto, int version,
db4e4c9a OK	45	const char *hostname, int hostname_len)
1da177e4	46	{
db4e4c9a OK	47	return nlm_lookup_host(0, sin, proto, version,
db4e4c9a OK	48	hostname, hostname_len);
1da177e4 LT	49	}
	50
	51	/*
	52	* Find an NLM client handle in the cache. If there is none, create it.
	53	*/
	54	struct nlm_host *
db4e4c9a OK	55	nlmsvc_lookup_host(struct svc_rqst *rqstp,
db4e4c9a OK	56	const char *hostname, int hostname_len)
1da177e4 LT	57	{
1da177e4 LT	58	return nlm_lookup_host(1, &rqstp->rq_addr,
db4e4c9a OK	59	rqstp->rq_prot, rqstp->rq_vers,
db4e4c9a OK	60	hostname, hostname_len);
1da177e4 LT	61	}
	62
	63	/*
	64	* Common host lookup routine for server & client
	65	*/
	66	struct nlm_host *
cf712c24	67	nlm_lookup_host(int server, const struct sockaddr_in *sin,
db4e4c9a OK	68	int proto, int version,
	69	const char *hostname,
	70	int hostname_len)
1da177e4	71	{
0cea3276 OK	72	struct hlist_head *chain;
	73	struct hlist_node *pos;
	74	struct nlm_host *host;
8dead0db	75	struct nsm_handle *nsm = NULL;
1da177e4 LT	76	int hash;
1da177e4 LT	77
db4e4c9a OK	78	dprintk("lockd: nlm_lookup_host(%u.%u.%u.%u, p=%d, v=%d, my role=%s, name=%.*s)\n",
	79	NIPQUAD(sin->sin_addr.s_addr), proto, version,
	80	server? "server" : "client",
	81	hostname_len,
	82	hostname? hostname : "<none>");
	83
1da177e4 LT	84
	85	hash = NLM_ADDRHASH(sin->sin_addr.s_addr);
	86
	87	/* Lock hash table */
353ab6e9	88	mutex_lock(&nlm_host_mutex);
1da177e4 LT	89
	90	if (time_after_eq(jiffies, next_gc))
	91	nlm_gc_hosts();
	92
8dead0db OK	93	/* We may keep several nlm_host objects for a peer, because each
	94	* nlm_host is identified by
	95	* (address, protocol, version, server/client)
	96	* We could probably simplify this a little by putting all those
	97	* different NLM rpc_clients into one single nlm_host object.
	98	* This would allow us to have one nlm_host per address.
	99	*/
0cea3276 OK	100	chain = &nlm_hosts[hash];
0cea3276 OK	101	hlist_for_each_entry(host, pos, chain, h_hash) {
8dead0db OK	102	if (!nlm_cmp_addr(&host->h_addr, sin))
	103	continue;
	104
	105	/* See if we have an NSM handle for this client */
	106	if (!nsm && (nsm = host->h_nsmhandle) != 0)
	107	atomic_inc(&nsm->sm_count);
	108
1da177e4 LT	109	if (host->h_proto != proto)
	110	continue;
	111	if (host->h_version != version)
	112	continue;
	113	if (host->h_server != server)
	114	continue;
	115
0cea3276 OK	116	/* Move to head of hash chain. */
	117	hlist_del(&host->h_hash);
	118	hlist_add_head(&host->h_hash, chain);
	119
f0737a39 OK	120	nlm_get_host(host);
f0737a39 OK	121	goto out;
1da177e4 LT	122	}
1da177e4 LT	123
0cea3276 OK	124	host = NULL;
0cea3276 OK	125
8dead0db OK	126	/* Sadly, the host isn't in our hash table yet. See if
	127	* we have an NSM handle for it. If not, create one.
	128	*/
	129	if (!nsm && !(nsm = nsm_find(sin, hostname, hostname_len)))
	130	goto out;
1da177e4	131
f8314dc6	132	host = kzalloc(sizeof(*host), GFP_KERNEL);
8dead0db OK	133	if (!host) {
	134	nsm_release(nsm);
	135	goto out;
	136	}
	137	host->h_name = nsm->sm_name;
1da177e4 LT	138	host->h_addr = *sin;
	139	host->h_addr.sin_port = 0; /* ouch! */
	140	host->h_version = version;
	141	host->h_proto = proto;
	142	host->h_rpcclnt = NULL;
50467914	143	mutex_init(&host->h_mutex);
1da177e4 LT	144	host->h_nextrebind = jiffies + NLM_HOST_REBIND;
	145	host->h_expires = jiffies + NLM_HOST_EXPIRE;
	146	atomic_set(&host->h_count, 1);
	147	init_waitqueue_head(&host->h_gracewait);
28df955a	148	init_rwsem(&host->h_rwsem);
1da177e4 LT	149	host->h_state = 0; /* pseudo NSM state */
1da177e4 LT	150	host->h_nsmstate = 0; /* real NSM state */
8dead0db	151	host->h_nsmhandle = nsm;
1da177e4	152	host->h_server = server;
0cea3276	153	hlist_add_head(&host->h_hash, chain);
1da177e4 LT	154	INIT_LIST_HEAD(&host->h_lockowners);
1da177e4 LT	155	spin_lock_init(&host->h_lock);
26bcbf96 CH	156	INIT_LIST_HEAD(&host->h_granted);
26bcbf96 CH	157	INIT_LIST_HEAD(&host->h_reclaim);
1da177e4 LT	158
	159	if (++nrhosts > NLM_HOST_MAX)
	160	next_gc = 0;
	161
8dead0db	162	out:
353ab6e9	163	mutex_unlock(&nlm_host_mutex);
1da177e4 LT	164	return host;
	165	}
	166
	167	struct nlm_host *
	168	nlm_find_client(void)
	169	{
0cea3276 OK	170	struct hlist_head *chain;
	171	struct hlist_node *pos;
	172
1da177e4 LT	173	/* find a nlm_host for a client for which h_killed == 0.
	174	* and return it
	175	*/
353ab6e9	176	mutex_lock(&nlm_host_mutex);
0cea3276 OK	177	for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
	178	struct nlm_host *host;
	179
	180	hlist_for_each_entry(host, pos, chain, h_hash) {
1da177e4 LT	181	if (host->h_server &&
	182	host->h_killed == 0) {
	183	nlm_get_host(host);
353ab6e9	184	mutex_unlock(&nlm_host_mutex);
1da177e4 LT	185	return host;
	186	}
	187	}
	188	}
353ab6e9	189	mutex_unlock(&nlm_host_mutex);
1da177e4 LT	190	return NULL;
	191	}
	192
	193
	194	/*
	195	* Create the NLM RPC client for an NLM peer
	196	*/
	197	struct rpc_clnt *
	198	nlm_bind_host(struct nlm_host *host)
	199	{
	200	struct rpc_clnt *clnt;
1da177e4 LT	201
	202	dprintk("lockd: nlm_bind_host(%08x)\n",
	203	(unsigned)ntohl(host->h_addr.sin_addr.s_addr));
	204
	205	/* Lock host handle */
50467914	206	mutex_lock(&host->h_mutex);
1da177e4 LT	207
	208	/* If we've already created an RPC client, check whether
	209	* RPC rebind is required
1da177e4 LT	210	*/
1da177e4 LT	211	if ((clnt = host->h_rpcclnt) != NULL) {
43118c29	212	if (time_after_eq(jiffies, host->h_nextrebind)) {
35f5a422	213	rpc_force_rebind(clnt);
1da177e4 LT	214	host->h_nextrebind = jiffies + NLM_HOST_REBIND;
	215	dprintk("lockd: next rebind in %ld jiffies\n",
	216	host->h_nextrebind - jiffies);
	217	}
	218	} else {
e1ec7892 CL	219	unsigned long increment = nlmsvc_timeout * HZ;
	220	struct rpc_timeout timeparms = {
	221	.to_initval = increment,
	222	.to_increment = increment,
	223	.to_maxval = increment * 6UL,
	224	.to_retries = 5U,
	225	};
	226	struct rpc_create_args args = {
	227	.protocol = host->h_proto,
	228	.address = (struct sockaddr *)&host->h_addr,
	229	.addrsize = sizeof(host->h_addr),
	230	.timeout = &timeparms,
	231	.servername = host->h_name,
	232	.program = &nlm_program,
	233	.version = host->h_version,
	234	.authflavor = RPC_AUTH_UNIX,
	235	.flags = (RPC_CLNT_CREATE_HARDRTRY \|
	236	RPC_CLNT_CREATE_AUTOBIND),
	237	};
	238
	239	clnt = rpc_create(&args);
	240	if (!IS_ERR(clnt))
	241	host->h_rpcclnt = clnt;
	242	else {
	243	printk("lockd: couldn't create RPC handle for %s\n", host->h_name);
	244	clnt = NULL;
	245	}
1da177e4 LT	246	}
1da177e4 LT	247
50467914	248	mutex_unlock(&host->h_mutex);
1da177e4	249	return clnt;
1da177e4 LT	250	}
	251
	252	/*
	253	* Force a portmap lookup of the remote lockd port
	254	*/
	255	void
	256	nlm_rebind_host(struct nlm_host *host)
	257	{
	258	dprintk("lockd: rebind host %s\n", host->h_name);
	259	if (host->h_rpcclnt && time_after_eq(jiffies, host->h_nextrebind)) {
35f5a422	260	rpc_force_rebind(host->h_rpcclnt);
1da177e4 LT	261	host->h_nextrebind = jiffies + NLM_HOST_REBIND;
	262	}
	263	}
	264
	265	/*
	266	* Increment NLM host count
	267	*/
	268	struct nlm_host * nlm_get_host(struct nlm_host *host)
	269	{
	270	if (host) {
	271	dprintk("lockd: get host %s\n", host->h_name);
	272	atomic_inc(&host->h_count);
	273	host->h_expires = jiffies + NLM_HOST_EXPIRE;
	274	}
	275	return host;
	276	}
	277
	278	/*
	279	* Release NLM host after use
	280	*/
	281	void nlm_release_host(struct nlm_host *host)
	282	{
	283	if (host != NULL) {
	284	dprintk("lockd: release host %s\n", host->h_name);
1da177e4	285	BUG_ON(atomic_read(&host->h_count) < 0);
4c060b53 TM	286	if (atomic_dec_and_test(&host->h_count)) {
	287	BUG_ON(!list_empty(&host->h_lockowners));
	288	BUG_ON(!list_empty(&host->h_granted));
	289	BUG_ON(!list_empty(&host->h_reclaim));
	290	}
1da177e4 LT	291	}
	292	}
	293
cf712c24 OK	294	/*
	295	* We were notified that the host indicated by address &sin
	296	* has rebooted.
	297	* Release all resources held by that peer.
	298	*/
5c8dd29c OK	299	void nlm_host_rebooted(const struct sockaddr_in *sin,
	300	const char *hostname, int hostname_len,
	301	u32 new_state)
cf712c24	302	{
0cea3276 OK	303	struct hlist_head *chain;
0cea3276 OK	304	struct hlist_node *pos;
5c8dd29c	305	struct nsm_handle *nsm;
0cea3276	306	struct nlm_host *host;
cf712c24	307
5c8dd29c OK	308	dprintk("lockd: nlm_host_rebooted(%s, %u.%u.%u.%u)\n",
	309	hostname, NIPQUAD(sin->sin_addr));
	310
	311	/* Find the NSM handle for this peer */
	312	if (!(nsm = __nsm_find(sin, hostname, hostname_len, 0)))
db4e4c9a OK	313	return;
db4e4c9a OK	314
5c8dd29c OK	315	/* When reclaiming locks on this peer, make sure that
	316	* we set up a new notification */
	317	nsm->sm_monitored = 0;
	318
	319	/* Mark all hosts tied to this NSM state as having rebooted.
	320	* We run the loop repeatedly, because we drop the host table
	321	* lock for this.
	322	* To avoid processing a host several times, we match the nsmstate.
	323	*/
	324	again: mutex_lock(&nlm_host_mutex);
0cea3276 OK	325	for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
0cea3276 OK	326	hlist_for_each_entry(host, pos, chain, h_hash) {
5c8dd29c OK	327	if (host->h_nsmhandle == nsm
	328	&& host->h_nsmstate != new_state) {
	329	host->h_nsmstate = new_state;
	330	host->h_state++;
	331
	332	nlm_get_host(host);
	333	mutex_unlock(&nlm_host_mutex);
	334
	335	if (host->h_server) {
	336	/* We're server for this guy, just ditch
	337	* all the locks he held. */
	338	nlmsvc_free_host_resources(host);
	339	} else {
	340	/* He's the server, initiate lock recovery. */
	341	nlmclnt_recovery(host);
	342	}
	343
	344	nlm_release_host(host);
	345	goto again;
	346	}
	347	}
cf712c24	348	}
5c8dd29c OK	349
5c8dd29c OK	350	mutex_unlock(&nlm_host_mutex);
cf712c24 OK	351	}
cf712c24 OK	352
1da177e4 LT	353	/*
	354	* Shut down the hosts module.
	355	* Note that this routine is called only at server shutdown time.
	356	*/
	357	void
	358	nlm_shutdown_hosts(void)
	359	{
0cea3276 OK	360	struct hlist_head *chain;
0cea3276 OK	361	struct hlist_node *pos;
1da177e4	362	struct nlm_host *host;
1da177e4 LT	363
1da177e4 LT	364	dprintk("lockd: shutting down host module\n");
353ab6e9	365	mutex_lock(&nlm_host_mutex);
1da177e4 LT	366
	367	/* First, make all hosts eligible for gc */
	368	dprintk("lockd: nuking all hosts...\n");
0cea3276 OK	369	for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
0cea3276 OK	370	hlist_for_each_entry(host, pos, chain, h_hash)
1da177e4 LT	371	host->h_expires = jiffies - 1;
	372	}
	373
	374	/* Then, perform a garbage collection pass */
	375	nlm_gc_hosts();
353ab6e9	376	mutex_unlock(&nlm_host_mutex);
1da177e4 LT	377
	378	/* complain if any hosts are left */
	379	if (nrhosts) {
	380	printk(KERN_WARNING "lockd: couldn't shutdown host module!\n");
	381	dprintk("lockd: %d hosts left:\n", nrhosts);
0cea3276 OK	382	for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
0cea3276 OK	383	hlist_for_each_entry(host, pos, chain, h_hash) {
1da177e4 LT	384	dprintk(" %s (cnt %d use %d exp %ld)\n",
	385	host->h_name, atomic_read(&host->h_count),
	386	host->h_inuse, host->h_expires);
	387	}
	388	}
	389	}
	390	}
	391
	392	/*
	393	* Garbage collect any unused NLM hosts.
	394	* This GC combines reference counting for async operations with
	395	* mark & sweep for resources held by remote clients.
	396	*/
	397	static void
	398	nlm_gc_hosts(void)
	399	{
0cea3276 OK	400	struct hlist_head *chain;
	401	struct hlist_node pos, next;
	402	struct nlm_host *host;
1da177e4	403	struct rpc_clnt *clnt;
1da177e4 LT	404
1da177e4 LT	405	dprintk("lockd: host garbage collection\n");
0cea3276 OK	406	for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
0cea3276 OK	407	hlist_for_each_entry(host, pos, chain, h_hash)
1da177e4 LT	408	host->h_inuse = 0;
	409	}
	410
	411	/* Mark all hosts that hold locks, blocks or shares */
	412	nlmsvc_mark_resources();
	413
0cea3276 OK	414	for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
0cea3276 OK	415	hlist_for_each_entry_safe(host, pos, next, chain, h_hash) {
1da177e4 LT	416	if (atomic_read(&host->h_count) \|\| host->h_inuse
	417	\|\| time_before(jiffies, host->h_expires)) {
	418	dprintk("nlm_gc_hosts skipping %s (cnt %d use %d exp %ld)\n",
	419	host->h_name, atomic_read(&host->h_count),
	420	host->h_inuse, host->h_expires);
1da177e4 LT	421	continue;
	422	}
	423	dprintk("lockd: delete host %s\n", host->h_name);
0cea3276	424	hlist_del_init(&host->h_hash);
977faf39 OK	425
	426	/*
	427	* Unmonitor unless host was invalidated (i.e. lockd restarted)
	428	*/
	429	nsm_unmonitor(host);
	430
1da177e4 LT	431	if ((clnt = host->h_rpcclnt) != NULL) {
	432	if (atomic_read(&clnt->cl_users)) {
	433	printk(KERN_WARNING
	434	"lockd: active RPC handle\n");
	435	clnt->cl_dead = 1;
	436	} else {
	437	rpc_destroy_client(host->h_rpcclnt);
	438	}
	439	}
1da177e4 LT	440	kfree(host);
	441	nrhosts--;
	442	}
	443	}
	444
	445	next_gc = jiffies + NLM_HOST_COLLECT;
	446	}
	447
8dead0db OK	448
	449	/*
	450	* Manage NSM handles
	451	*/
	452	static LIST_HEAD(nsm_handles);
	453	static DECLARE_MUTEX(nsm_sema);
	454
	455	static struct nsm_handle *
	456	__nsm_find(const struct sockaddr_in *sin,
	457	const char *hostname, int hostname_len,
	458	int create)
	459	{
	460	struct nsm_handle *nsm = NULL;
	461	struct list_head *pos;
	462
	463	if (!sin)
	464	return NULL;
	465
	466	if (hostname && memchr(hostname, '/', hostname_len) != NULL) {
	467	if (printk_ratelimit()) {
	468	printk(KERN_WARNING "Invalid hostname \"%.*s\" "
	469	"in NFS lock request\n",
	470	hostname_len, hostname);
	471	}
	472	return NULL;
	473	}
	474
	475	down(&nsm_sema);
	476	list_for_each(pos, &nsm_handles) {
	477	nsm = list_entry(pos, struct nsm_handle, sm_link);
	478
	479	if (!nlm_cmp_addr(&nsm->sm_addr, sin))
	480	continue;
	481	atomic_inc(&nsm->sm_count);
	482	goto out;
	483	}
	484
	485	if (!create) {
	486	nsm = NULL;
	487	goto out;
	488	}
	489
	490	nsm = kzalloc(sizeof(*nsm) + hostname_len + 1, GFP_KERNEL);
	491	if (nsm != NULL) {
	492	nsm->sm_addr = *sin;
	493	nsm->sm_name = (char *) (nsm + 1);
	494	memcpy(nsm->sm_name, hostname, hostname_len);
	495	nsm->sm_name[hostname_len] = '\0';
	496	atomic_set(&nsm->sm_count, 1);
	497
	498	list_add(&nsm->sm_link, &nsm_handles);
	499	}
	500
	501	out: up(&nsm_sema);
	502	return nsm;
	503	}
	504
	505	struct nsm_handle *
	506	nsm_find(const struct sockaddr_in sin, const char hostname, int hostname_len)
	507	{
	508	return __nsm_find(sin, hostname, hostname_len, 1);
	509	}
	510
	511	/*
512	* Release an NSM handle
513	*/
514	void
515	nsm_release(struct nsm_handle *nsm)
516	{
517	if (!nsm)
518	return;
519	if (atomic_dec_and_test(&nsm->sm_count)) {
520	down(&nsm_sema);
521	if (atomic_read(&nsm->sm_count) == 0) {
522	list_del(&nsm->sm_link);
523	kfree(nsm);
524	}
525	up(&nsm_sema);
526	}
527	}