[mirror_ubuntu-bionic-kernel.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;

		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;
	}
	if (nsm)
		atomic_inc(&nsm->sm_count);

	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;
}

/*
 * Destroy a host
 */
static void
nlm_destroy_host(struct nlm_host *host)
{
	struct rpc_clnt	*clnt;

	BUG_ON(!list_empty(&host->h_lockowners));
	BUG_ON(atomic_read(&host->h_count));

	/*
	 * Release NSM handle and unmonitor host.
	 */
	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);
}

/*
 * 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;

	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);

			nlm_destroy_host(host);
			nrhosts--;
		}
	}

	next_gc = jiffies + NLM_HOST_COLLECT;
}


/*
 * Manage NSM handles
 */
static LIST_HEAD(nsm_handles);
static DEFINE_MUTEX(nsm_mutex);

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;
	}

	mutex_lock(&nsm_mutex);
	list_for_each(pos, &nsm_handles) {
		nsm = list_entry(pos, struct nsm_handle, sm_link);

		if (hostname && nsm_use_hostnames) {
			if (strlen(nsm->sm_name) != hostname_len
			 || memcmp(nsm->sm_name, hostname, hostname_len))
				continue;
		} else 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:
	mutex_unlock(&nsm_mutex);
	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)) {
		mutex_lock(&nsm_mutex);
		if (atomic_read(&nsm->sm_count) == 0) {
			list_del(&nsm->sm_link);
			kfree(nsm);
		}
		mutex_unlock(&nsm_mutex);
	}
}
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 */
6b54dae2 N	106	if (!nsm)
6b54dae2 N	107	nsm = host->h_nsmhandle;
8dead0db	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	122	}
6b54dae2 N	123	if (nsm)
6b54dae2 N	124	atomic_inc(&nsm->sm_count);
1da177e4	125
0cea3276 OK	126	host = NULL;
0cea3276 OK	127
8dead0db OK	128	/* Sadly, the host isn't in our hash table yet. See if
	129	* we have an NSM handle for it. If not, create one.
	130	*/
	131	if (!nsm && !(nsm = nsm_find(sin, hostname, hostname_len)))
	132	goto out;
1da177e4	133
f8314dc6	134	host = kzalloc(sizeof(*host), GFP_KERNEL);
8dead0db OK	135	if (!host) {
	136	nsm_release(nsm);
	137	goto out;
	138	}
	139	host->h_name = nsm->sm_name;
1da177e4 LT	140	host->h_addr = *sin;
	141	host->h_addr.sin_port = 0; /* ouch! */
	142	host->h_version = version;
	143	host->h_proto = proto;
	144	host->h_rpcclnt = NULL;
50467914	145	mutex_init(&host->h_mutex);
1da177e4 LT	146	host->h_nextrebind = jiffies + NLM_HOST_REBIND;
	147	host->h_expires = jiffies + NLM_HOST_EXPIRE;
	148	atomic_set(&host->h_count, 1);
	149	init_waitqueue_head(&host->h_gracewait);
28df955a	150	init_rwsem(&host->h_rwsem);
1da177e4 LT	151	host->h_state = 0; /* pseudo NSM state */
1da177e4 LT	152	host->h_nsmstate = 0; /* real NSM state */
8dead0db	153	host->h_nsmhandle = nsm;
1da177e4	154	host->h_server = server;
0cea3276	155	hlist_add_head(&host->h_hash, chain);
1da177e4 LT	156	INIT_LIST_HEAD(&host->h_lockowners);
1da177e4 LT	157	spin_lock_init(&host->h_lock);
26bcbf96 CH	158	INIT_LIST_HEAD(&host->h_granted);
26bcbf96 CH	159	INIT_LIST_HEAD(&host->h_reclaim);
1da177e4 LT	160
	161	if (++nrhosts > NLM_HOST_MAX)
	162	next_gc = 0;
	163
8dead0db	164	out:
353ab6e9	165	mutex_unlock(&nlm_host_mutex);
1da177e4 LT	166	return host;
	167	}
	168
c53c1bb9 OK	169	/*
	170	* Destroy a host
	171	*/
	172	static void
	173	nlm_destroy_host(struct nlm_host *host)
	174	{
	175	struct rpc_clnt *clnt;
	176
	177	BUG_ON(!list_empty(&host->h_lockowners));
	178	BUG_ON(atomic_read(&host->h_count));
	179
	180	/*
	181	* Release NSM handle and unmonitor host.
	182	*/
	183	nsm_unmonitor(host);
	184
	185	if ((clnt = host->h_rpcclnt) != NULL) {
	186	if (atomic_read(&clnt->cl_users)) {
	187	printk(KERN_WARNING
	188	"lockd: active RPC handle\n");
	189	clnt->cl_dead = 1;
	190	} else {
	191	rpc_destroy_client(host->h_rpcclnt);
	192	}
	193	}
	194	kfree(host);
	195	}
	196
1da177e4 LT	197	/*
	198	* Create the NLM RPC client for an NLM peer
	199	*/
	200	struct rpc_clnt *
	201	nlm_bind_host(struct nlm_host *host)
	202	{
	203	struct rpc_clnt *clnt;
1da177e4 LT	204
	205	dprintk("lockd: nlm_bind_host(%08x)\n",
	206	(unsigned)ntohl(host->h_addr.sin_addr.s_addr));
	207
	208	/* Lock host handle */
50467914	209	mutex_lock(&host->h_mutex);
1da177e4 LT	210
	211	/* If we've already created an RPC client, check whether
	212	* RPC rebind is required
1da177e4 LT	213	*/
1da177e4 LT	214	if ((clnt = host->h_rpcclnt) != NULL) {
43118c29	215	if (time_after_eq(jiffies, host->h_nextrebind)) {
35f5a422	216	rpc_force_rebind(clnt);
1da177e4 LT	217	host->h_nextrebind = jiffies + NLM_HOST_REBIND;
	218	dprintk("lockd: next rebind in %ld jiffies\n",
	219	host->h_nextrebind - jiffies);
	220	}
	221	} else {
e1ec7892 CL	222	unsigned long increment = nlmsvc_timeout * HZ;
	223	struct rpc_timeout timeparms = {
	224	.to_initval = increment,
	225	.to_increment = increment,
	226	.to_maxval = increment * 6UL,
	227	.to_retries = 5U,
	228	};
	229	struct rpc_create_args args = {
	230	.protocol = host->h_proto,
	231	.address = (struct sockaddr *)&host->h_addr,
	232	.addrsize = sizeof(host->h_addr),
	233	.timeout = &timeparms,
	234	.servername = host->h_name,
	235	.program = &nlm_program,
	236	.version = host->h_version,
	237	.authflavor = RPC_AUTH_UNIX,
	238	.flags = (RPC_CLNT_CREATE_HARDRTRY \|
	239	RPC_CLNT_CREATE_AUTOBIND),
	240	};
	241
	242	clnt = rpc_create(&args);
	243	if (!IS_ERR(clnt))
	244	host->h_rpcclnt = clnt;
	245	else {
	246	printk("lockd: couldn't create RPC handle for %s\n", host->h_name);
	247	clnt = NULL;
	248	}
1da177e4 LT	249	}
1da177e4 LT	250
50467914	251	mutex_unlock(&host->h_mutex);
1da177e4	252	return clnt;
1da177e4 LT	253	}
	254
	255	/*
	256	* Force a portmap lookup of the remote lockd port
	257	*/
	258	void
	259	nlm_rebind_host(struct nlm_host *host)
	260	{
	261	dprintk("lockd: rebind host %s\n", host->h_name);
	262	if (host->h_rpcclnt && time_after_eq(jiffies, host->h_nextrebind)) {
35f5a422	263	rpc_force_rebind(host->h_rpcclnt);
1da177e4 LT	264	host->h_nextrebind = jiffies + NLM_HOST_REBIND;
	265	}
	266	}
	267
	268	/*
	269	* Increment NLM host count
	270	*/
	271	struct nlm_host * nlm_get_host(struct nlm_host *host)
	272	{
	273	if (host) {
	274	dprintk("lockd: get host %s\n", host->h_name);
	275	atomic_inc(&host->h_count);
	276	host->h_expires = jiffies + NLM_HOST_EXPIRE;
	277	}
	278	return host;
	279	}
	280
	281	/*
	282	* Release NLM host after use
	283	*/
	284	void nlm_release_host(struct nlm_host *host)
	285	{
	286	if (host != NULL) {
	287	dprintk("lockd: release host %s\n", host->h_name);
1da177e4	288	BUG_ON(atomic_read(&host->h_count) < 0);
4c060b53 TM	289	if (atomic_dec_and_test(&host->h_count)) {
	290	BUG_ON(!list_empty(&host->h_lockowners));
	291	BUG_ON(!list_empty(&host->h_granted));
	292	BUG_ON(!list_empty(&host->h_reclaim));
	293	}
1da177e4 LT	294	}
	295	}
	296
cf712c24 OK	297	/*
	298	* We were notified that the host indicated by address &sin
	299	* has rebooted.
	300	* Release all resources held by that peer.
	301	*/
5c8dd29c OK	302	void nlm_host_rebooted(const struct sockaddr_in *sin,
	303	const char *hostname, int hostname_len,
	304	u32 new_state)
cf712c24	305	{
0cea3276 OK	306	struct hlist_head *chain;
0cea3276 OK	307	struct hlist_node *pos;
5c8dd29c	308	struct nsm_handle *nsm;
0cea3276	309	struct nlm_host *host;
cf712c24	310
5c8dd29c OK	311	dprintk("lockd: nlm_host_rebooted(%s, %u.%u.%u.%u)\n",
	312	hostname, NIPQUAD(sin->sin_addr));
	313
	314	/* Find the NSM handle for this peer */
	315	if (!(nsm = __nsm_find(sin, hostname, hostname_len, 0)))
db4e4c9a OK	316	return;
db4e4c9a OK	317
5c8dd29c OK	318	/* When reclaiming locks on this peer, make sure that
	319	* we set up a new notification */
	320	nsm->sm_monitored = 0;
	321
	322	/* Mark all hosts tied to this NSM state as having rebooted.
	323	* We run the loop repeatedly, because we drop the host table
	324	* lock for this.
	325	* To avoid processing a host several times, we match the nsmstate.
	326	*/
	327	again: mutex_lock(&nlm_host_mutex);
0cea3276 OK	328	for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
0cea3276 OK	329	hlist_for_each_entry(host, pos, chain, h_hash) {
5c8dd29c OK	330	if (host->h_nsmhandle == nsm
	331	&& host->h_nsmstate != new_state) {
	332	host->h_nsmstate = new_state;
	333	host->h_state++;
	334
	335	nlm_get_host(host);
	336	mutex_unlock(&nlm_host_mutex);
	337
	338	if (host->h_server) {
	339	/* We're server for this guy, just ditch
	340	* all the locks he held. */
	341	nlmsvc_free_host_resources(host);
	342	} else {
	343	/* He's the server, initiate lock recovery. */
	344	nlmclnt_recovery(host);
	345	}
	346
	347	nlm_release_host(host);
	348	goto again;
	349	}
	350	}
cf712c24	351	}
5c8dd29c OK	352
5c8dd29c OK	353	mutex_unlock(&nlm_host_mutex);
cf712c24 OK	354	}
cf712c24 OK	355
1da177e4 LT	356	/*
	357	* Shut down the hosts module.
	358	* Note that this routine is called only at server shutdown time.
	359	*/
	360	void
	361	nlm_shutdown_hosts(void)
	362	{
0cea3276 OK	363	struct hlist_head *chain;
0cea3276 OK	364	struct hlist_node *pos;
1da177e4	365	struct nlm_host *host;
1da177e4 LT	366
1da177e4 LT	367	dprintk("lockd: shutting down host module\n");
353ab6e9	368	mutex_lock(&nlm_host_mutex);
1da177e4 LT	369
	370	/* First, make all hosts eligible for gc */
	371	dprintk("lockd: nuking all hosts...\n");
0cea3276 OK	372	for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
0cea3276 OK	373	hlist_for_each_entry(host, pos, chain, h_hash)
1da177e4 LT	374	host->h_expires = jiffies - 1;
	375	}
	376
	377	/* Then, perform a garbage collection pass */
	378	nlm_gc_hosts();
353ab6e9	379	mutex_unlock(&nlm_host_mutex);
1da177e4 LT	380
	381	/* complain if any hosts are left */
	382	if (nrhosts) {
	383	printk(KERN_WARNING "lockd: couldn't shutdown host module!\n");
	384	dprintk("lockd: %d hosts left:\n", nrhosts);
0cea3276 OK	385	for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
0cea3276 OK	386	hlist_for_each_entry(host, pos, chain, h_hash) {
1da177e4 LT	387	dprintk(" %s (cnt %d use %d exp %ld)\n",
	388	host->h_name, atomic_read(&host->h_count),
	389	host->h_inuse, host->h_expires);
	390	}
	391	}
	392	}
	393	}
	394
	395	/*
	396	* Garbage collect any unused NLM hosts.
	397	* This GC combines reference counting for async operations with
	398	* mark & sweep for resources held by remote clients.
	399	*/
	400	static void
	401	nlm_gc_hosts(void)
	402	{
0cea3276 OK	403	struct hlist_head *chain;
	404	struct hlist_node pos, next;
	405	struct nlm_host *host;
1da177e4 LT	406
1da177e4 LT	407	dprintk("lockd: host garbage collection\n");
0cea3276 OK	408	for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
0cea3276 OK	409	hlist_for_each_entry(host, pos, chain, h_hash)
1da177e4 LT	410	host->h_inuse = 0;
	411	}
	412
	413	/* Mark all hosts that hold locks, blocks or shares */
	414	nlmsvc_mark_resources();
	415
0cea3276 OK	416	for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
0cea3276 OK	417	hlist_for_each_entry_safe(host, pos, next, chain, h_hash) {
1da177e4 LT	418	if (atomic_read(&host->h_count) \|\| host->h_inuse
	419	\|\| time_before(jiffies, host->h_expires)) {
	420	dprintk("nlm_gc_hosts skipping %s (cnt %d use %d exp %ld)\n",
	421	host->h_name, atomic_read(&host->h_count),
	422	host->h_inuse, host->h_expires);
1da177e4 LT	423	continue;
	424	}
	425	dprintk("lockd: delete host %s\n", host->h_name);
0cea3276	426	hlist_del_init(&host->h_hash);
977faf39	427
c53c1bb9	428	nlm_destroy_host(host);
1da177e4 LT	429	nrhosts--;
	430	}
	431	}
	432
	433	next_gc = jiffies + NLM_HOST_COLLECT;
	434	}
	435
8dead0db OK	436
	437	/*
	438	* Manage NSM handles
	439	*/
	440	static LIST_HEAD(nsm_handles);
89e63ef6	441	static DEFINE_MUTEX(nsm_mutex);
8dead0db OK	442
	443	static struct nsm_handle *
	444	__nsm_find(const struct sockaddr_in *sin,
	445	const char *hostname, int hostname_len,
	446	int create)
	447	{
	448	struct nsm_handle *nsm = NULL;
	449	struct list_head *pos;
	450
	451	if (!sin)
	452	return NULL;
	453
	454	if (hostname && memchr(hostname, '/', hostname_len) != NULL) {
	455	if (printk_ratelimit()) {
	456	printk(KERN_WARNING "Invalid hostname \"%.*s\" "
	457	"in NFS lock request\n",
	458	hostname_len, hostname);
	459	}
	460	return NULL;
	461	}
	462
89e63ef6	463	mutex_lock(&nsm_mutex);
8dead0db OK	464	list_for_each(pos, &nsm_handles) {
	465	nsm = list_entry(pos, struct nsm_handle, sm_link);
	466
abd1f500 OK	467	if (hostname && nsm_use_hostnames) {
	468	if (strlen(nsm->sm_name) != hostname_len
	469	\|\| memcmp(nsm->sm_name, hostname, hostname_len))
	470	continue;
	471	} else if (!nlm_cmp_addr(&nsm->sm_addr, sin))
8dead0db OK	472	continue;
	473	atomic_inc(&nsm->sm_count);
	474	goto out;
	475	}
	476
	477	if (!create) {
	478	nsm = NULL;
	479	goto out;
	480	}
	481
	482	nsm = kzalloc(sizeof(*nsm) + hostname_len + 1, GFP_KERNEL);
	483	if (nsm != NULL) {
	484	nsm->sm_addr = *sin;
	485	nsm->sm_name = (char *) (nsm + 1);
	486	memcpy(nsm->sm_name, hostname, hostname_len);
	487	nsm->sm_name[hostname_len] = '\0';
	488	atomic_set(&nsm->sm_count, 1);
	489
	490	list_add(&nsm->sm_link, &nsm_handles);
	491	}
	492
89e63ef6 NB	493	out:
89e63ef6 NB	494	mutex_unlock(&nsm_mutex);
8dead0db OK	495	return nsm;
	496	}
	497
	498	struct nsm_handle *
	499	nsm_find(const struct sockaddr_in sin, const char hostname, int hostname_len)
	500	{
	501	return __nsm_find(sin, hostname, hostname_len, 1);
	502	}
	503
	504	/*
	505	* Release an NSM handle
	506	*/
	507	void
	508	nsm_release(struct nsm_handle *nsm)
	509	{
	510	if (!nsm)
	511	return;
	512	if (atomic_dec_and_test(&nsm->sm_count)) {
89e63ef6	513	mutex_lock(&nsm_mutex);
8dead0db OK	514	if (atomic_read(&nsm->sm_count) == 0) {
	515	list_del(&nsm->sm_link);
	516	kfree(nsm);
	517	}
89e63ef6	518	mutex_unlock(&nsm_mutex);
8dead0db OK	519	}
8dead0db OK	520	}