[mirror_ubuntu-artful-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/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);
static struct nsm_handle *	nsm_find(const struct sockaddr_in *sin,
					 const char *hostname,
					 int hostname_len);

/*
 * Common host lookup routine for server & client
 */
static 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);
}

/*
 * 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, svc_addr_in(rqstp),
			       rqstp->rq_prot, rqstp->rq_vers,
			       hostname, hostname_len);
}

/*
 * 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;
}

static 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>
1da177e4 LT	12	#include <linux/slab.h>
	13	#include <linux/in.h>
	14	#include <linux/sunrpc/clnt.h>
	15	#include <linux/sunrpc/svc.h>
	16	#include <linux/lockd/lockd.h>
	17	#include <linux/lockd/sm_inter.h>
353ab6e9	18	#include <linux/mutex.h>
1da177e4 LT	19
	20
	21	#define NLMDBG_FACILITY NLMDBG_HOSTCACHE
	22	#define NLM_HOST_MAX 64
	23	#define NLM_HOST_NRHASH 32
	24	#define NLM_ADDRHASH(addr) (ntohl(addr) & (NLM_HOST_NRHASH-1))
	25	#define NLM_HOST_REBIND (60 * HZ)
	26	#define NLM_HOST_EXPIRE ((nrhosts > NLM_HOST_MAX)? 300 * HZ : 120 * HZ)
	27	#define NLM_HOST_COLLECT ((nrhosts > NLM_HOST_MAX)? 120 * HZ : 60 * HZ)
1da177e4	28
0cea3276	29	static struct hlist_head nlm_hosts[NLM_HOST_NRHASH];
1da177e4 LT	30	static unsigned long next_gc;
1da177e4 LT	31	static int nrhosts;
353ab6e9	32	static DEFINE_MUTEX(nlm_host_mutex);
1da177e4 LT	33
	34
	35	static void nlm_gc_hosts(void);
8dead0db OK	36	static struct nsm_handle * __nsm_find(const struct sockaddr_in *,
8dead0db OK	37	const char *, int, int);
c585646d AB	38	static struct nsm_handle * nsm_find(const struct sockaddr_in *sin,
	39	const char *hostname,
	40	int hostname_len);
1da177e4 LT	41
	42	/*
	43	* Common host lookup routine for server & client
	44	*/
c585646d	45	static struct nlm_host *
cf712c24	46	nlm_lookup_host(int server, const struct sockaddr_in *sin,
db4e4c9a OK	47	int proto, int version,
	48	const char *hostname,
	49	int hostname_len)
1da177e4	50	{
0cea3276 OK	51	struct hlist_head *chain;
	52	struct hlist_node *pos;
	53	struct nlm_host *host;
8dead0db	54	struct nsm_handle *nsm = NULL;
1da177e4 LT	55	int hash;
1da177e4 LT	56
db4e4c9a OK	57	dprintk("lockd: nlm_lookup_host(%u.%u.%u.%u, p=%d, v=%d, my role=%s, name=%.*s)\n",
	58	NIPQUAD(sin->sin_addr.s_addr), proto, version,
	59	server? "server" : "client",
	60	hostname_len,
	61	hostname? hostname : "<none>");
	62
1da177e4 LT	63
	64	hash = NLM_ADDRHASH(sin->sin_addr.s_addr);
	65
	66	/* Lock hash table */
353ab6e9	67	mutex_lock(&nlm_host_mutex);
1da177e4 LT	68
	69	if (time_after_eq(jiffies, next_gc))
	70	nlm_gc_hosts();
	71
8dead0db OK	72	/* We may keep several nlm_host objects for a peer, because each
	73	* nlm_host is identified by
	74	* (address, protocol, version, server/client)
	75	* We could probably simplify this a little by putting all those
	76	* different NLM rpc_clients into one single nlm_host object.
	77	* This would allow us to have one nlm_host per address.
	78	*/
0cea3276 OK	79	chain = &nlm_hosts[hash];
0cea3276 OK	80	hlist_for_each_entry(host, pos, chain, h_hash) {
8dead0db OK	81	if (!nlm_cmp_addr(&host->h_addr, sin))
	82	continue;
	83
	84	/* See if we have an NSM handle for this client */
6b54dae2 N	85	if (!nsm)
6b54dae2 N	86	nsm = host->h_nsmhandle;
8dead0db	87
1da177e4 LT	88	if (host->h_proto != proto)
	89	continue;
	90	if (host->h_version != version)
	91	continue;
	92	if (host->h_server != server)
	93	continue;
	94
0cea3276 OK	95	/* Move to head of hash chain. */
	96	hlist_del(&host->h_hash);
	97	hlist_add_head(&host->h_hash, chain);
	98
f0737a39 OK	99	nlm_get_host(host);
f0737a39 OK	100	goto out;
1da177e4	101	}
6b54dae2 N	102	if (nsm)
6b54dae2 N	103	atomic_inc(&nsm->sm_count);
1da177e4	104
0cea3276 OK	105	host = NULL;
0cea3276 OK	106
8dead0db OK	107	/* Sadly, the host isn't in our hash table yet. See if
	108	* we have an NSM handle for it. If not, create one.
	109	*/
	110	if (!nsm && !(nsm = nsm_find(sin, hostname, hostname_len)))
	111	goto out;
1da177e4	112
f8314dc6	113	host = kzalloc(sizeof(*host), GFP_KERNEL);
8dead0db OK	114	if (!host) {
	115	nsm_release(nsm);
	116	goto out;
	117	}
	118	host->h_name = nsm->sm_name;
1da177e4 LT	119	host->h_addr = *sin;
	120	host->h_addr.sin_port = 0; /* ouch! */
	121	host->h_version = version;
	122	host->h_proto = proto;
	123	host->h_rpcclnt = NULL;
50467914	124	mutex_init(&host->h_mutex);
1da177e4 LT	125	host->h_nextrebind = jiffies + NLM_HOST_REBIND;
	126	host->h_expires = jiffies + NLM_HOST_EXPIRE;
	127	atomic_set(&host->h_count, 1);
	128	init_waitqueue_head(&host->h_gracewait);
28df955a	129	init_rwsem(&host->h_rwsem);
1da177e4 LT	130	host->h_state = 0; /* pseudo NSM state */
1da177e4 LT	131	host->h_nsmstate = 0; /* real NSM state */
8dead0db	132	host->h_nsmhandle = nsm;
1da177e4	133	host->h_server = server;
0cea3276	134	hlist_add_head(&host->h_hash, chain);
1da177e4 LT	135	INIT_LIST_HEAD(&host->h_lockowners);
1da177e4 LT	136	spin_lock_init(&host->h_lock);
26bcbf96 CH	137	INIT_LIST_HEAD(&host->h_granted);
26bcbf96 CH	138	INIT_LIST_HEAD(&host->h_reclaim);
1da177e4 LT	139
	140	if (++nrhosts > NLM_HOST_MAX)
	141	next_gc = 0;
	142
8dead0db	143	out:
353ab6e9	144	mutex_unlock(&nlm_host_mutex);
1da177e4 LT	145	return host;
	146	}
	147
c53c1bb9 OK	148	/*
	149	* Destroy a host
	150	*/
	151	static void
	152	nlm_destroy_host(struct nlm_host *host)
	153	{
	154	struct rpc_clnt *clnt;
	155
	156	BUG_ON(!list_empty(&host->h_lockowners));
	157	BUG_ON(atomic_read(&host->h_count));
	158
	159	/*
	160	* Release NSM handle and unmonitor host.
	161	*/
	162	nsm_unmonitor(host);
	163
	164	if ((clnt = host->h_rpcclnt) != NULL) {
	165	if (atomic_read(&clnt->cl_users)) {
	166	printk(KERN_WARNING
	167	"lockd: active RPC handle\n");
	168	clnt->cl_dead = 1;
	169	} else {
	170	rpc_destroy_client(host->h_rpcclnt);
	171	}
	172	}
	173	kfree(host);
	174	}
	175
c585646d AB	176	/*
	177	* Find an NLM server handle in the cache. If there is none, create it.
	178	*/
	179	struct nlm_host *
	180	nlmclnt_lookup_host(const struct sockaddr_in *sin, int proto, int version,
	181	const char *hostname, int hostname_len)
	182	{
	183	return nlm_lookup_host(0, sin, proto, version,
	184	hostname, hostname_len);
	185	}
	186
	187	/*
	188	* Find an NLM client handle in the cache. If there is none, create it.
	189	*/
	190	struct nlm_host *
	191	nlmsvc_lookup_host(struct svc_rqst *rqstp,
	192	const char *hostname, int hostname_len)
	193	{
27459f09	194	return nlm_lookup_host(1, svc_addr_in(rqstp),
c585646d AB	195	rqstp->rq_prot, rqstp->rq_vers,
	196	hostname, hostname_len);
	197	}
	198
1da177e4 LT	199	/*
	200	* Create the NLM RPC client for an NLM peer
	201	*/
	202	struct rpc_clnt *
	203	nlm_bind_host(struct nlm_host *host)
	204	{
	205	struct rpc_clnt *clnt;
1da177e4 LT	206
	207	dprintk("lockd: nlm_bind_host(%08x)\n",
	208	(unsigned)ntohl(host->h_addr.sin_addr.s_addr));
	209
	210	/* Lock host handle */
50467914	211	mutex_lock(&host->h_mutex);
1da177e4 LT	212
	213	/* If we've already created an RPC client, check whether
	214	* RPC rebind is required
1da177e4 LT	215	*/
1da177e4 LT	216	if ((clnt = host->h_rpcclnt) != NULL) {
43118c29	217	if (time_after_eq(jiffies, host->h_nextrebind)) {
35f5a422	218	rpc_force_rebind(clnt);
1da177e4 LT	219	host->h_nextrebind = jiffies + NLM_HOST_REBIND;
	220	dprintk("lockd: next rebind in %ld jiffies\n",
	221	host->h_nextrebind - jiffies);
	222	}
	223	} else {
e1ec7892 CL	224	unsigned long increment = nlmsvc_timeout * HZ;
	225	struct rpc_timeout timeparms = {
	226	.to_initval = increment,
	227	.to_increment = increment,
	228	.to_maxval = increment * 6UL,
	229	.to_retries = 5U,
	230	};
	231	struct rpc_create_args args = {
	232	.protocol = host->h_proto,
	233	.address = (struct sockaddr *)&host->h_addr,
	234	.addrsize = sizeof(host->h_addr),
	235	.timeout = &timeparms,
	236	.servername = host->h_name,
	237	.program = &nlm_program,
	238	.version = host->h_version,
	239	.authflavor = RPC_AUTH_UNIX,
	240	.flags = (RPC_CLNT_CREATE_HARDRTRY \|
	241	RPC_CLNT_CREATE_AUTOBIND),
	242	};
	243
	244	clnt = rpc_create(&args);
	245	if (!IS_ERR(clnt))
	246	host->h_rpcclnt = clnt;
	247	else {
	248	printk("lockd: couldn't create RPC handle for %s\n", host->h_name);
	249	clnt = NULL;
	250	}
1da177e4 LT	251	}
1da177e4 LT	252
50467914	253	mutex_unlock(&host->h_mutex);
1da177e4	254	return clnt;
1da177e4 LT	255	}
	256
	257	/*
	258	* Force a portmap lookup of the remote lockd port
	259	*/
	260	void
	261	nlm_rebind_host(struct nlm_host *host)
	262	{
	263	dprintk("lockd: rebind host %s\n", host->h_name);
	264	if (host->h_rpcclnt && time_after_eq(jiffies, host->h_nextrebind)) {
35f5a422	265	rpc_force_rebind(host->h_rpcclnt);
1da177e4 LT	266	host->h_nextrebind = jiffies + NLM_HOST_REBIND;
	267	}
	268	}
	269
	270	/*
	271	* Increment NLM host count
	272	*/
	273	struct nlm_host * nlm_get_host(struct nlm_host *host)
	274	{
	275	if (host) {
	276	dprintk("lockd: get host %s\n", host->h_name);
	277	atomic_inc(&host->h_count);
	278	host->h_expires = jiffies + NLM_HOST_EXPIRE;
	279	}
	280	return host;
	281	}
	282
	283	/*
	284	* Release NLM host after use
	285	*/
	286	void nlm_release_host(struct nlm_host *host)
	287	{
	288	if (host != NULL) {
	289	dprintk("lockd: release host %s\n", host->h_name);
1da177e4	290	BUG_ON(atomic_read(&host->h_count) < 0);
4c060b53 TM	291	if (atomic_dec_and_test(&host->h_count)) {
	292	BUG_ON(!list_empty(&host->h_lockowners));
	293	BUG_ON(!list_empty(&host->h_granted));
	294	BUG_ON(!list_empty(&host->h_reclaim));
	295	}
1da177e4 LT	296	}
	297	}
	298
cf712c24 OK	299	/*
	300	* We were notified that the host indicated by address &sin
	301	* has rebooted.
	302	* Release all resources held by that peer.
	303	*/
5c8dd29c OK	304	void nlm_host_rebooted(const struct sockaddr_in *sin,
	305	const char *hostname, int hostname_len,
	306	u32 new_state)
cf712c24	307	{
0cea3276 OK	308	struct hlist_head *chain;
0cea3276 OK	309	struct hlist_node *pos;
5c8dd29c	310	struct nsm_handle *nsm;
0cea3276	311	struct nlm_host *host;
cf712c24	312
5c8dd29c OK	313	dprintk("lockd: nlm_host_rebooted(%s, %u.%u.%u.%u)\n",
	314	hostname, NIPQUAD(sin->sin_addr));
	315
	316	/* Find the NSM handle for this peer */
	317	if (!(nsm = __nsm_find(sin, hostname, hostname_len, 0)))
db4e4c9a OK	318	return;
db4e4c9a OK	319
5c8dd29c OK	320	/* When reclaiming locks on this peer, make sure that
	321	* we set up a new notification */
	322	nsm->sm_monitored = 0;
	323
	324	/* Mark all hosts tied to this NSM state as having rebooted.
	325	* We run the loop repeatedly, because we drop the host table
	326	* lock for this.
	327	* To avoid processing a host several times, we match the nsmstate.
	328	*/
	329	again: mutex_lock(&nlm_host_mutex);
0cea3276 OK	330	for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
0cea3276 OK	331	hlist_for_each_entry(host, pos, chain, h_hash) {
5c8dd29c OK	332	if (host->h_nsmhandle == nsm
	333	&& host->h_nsmstate != new_state) {
	334	host->h_nsmstate = new_state;
	335	host->h_state++;
	336
	337	nlm_get_host(host);
	338	mutex_unlock(&nlm_host_mutex);
	339
	340	if (host->h_server) {
	341	/* We're server for this guy, just ditch
	342	* all the locks he held. */
	343	nlmsvc_free_host_resources(host);
	344	} else {
	345	/* He's the server, initiate lock recovery. */
	346	nlmclnt_recovery(host);
	347	}
	348
	349	nlm_release_host(host);
	350	goto again;
	351	}
	352	}
cf712c24	353	}
5c8dd29c OK	354
5c8dd29c OK	355	mutex_unlock(&nlm_host_mutex);
cf712c24 OK	356	}
cf712c24 OK	357
1da177e4 LT	358	/*
	359	* Shut down the hosts module.
	360	* Note that this routine is called only at server shutdown time.
	361	*/
	362	void
	363	nlm_shutdown_hosts(void)
	364	{
0cea3276 OK	365	struct hlist_head *chain;
0cea3276 OK	366	struct hlist_node *pos;
1da177e4	367	struct nlm_host *host;
1da177e4 LT	368
1da177e4 LT	369	dprintk("lockd: shutting down host module\n");
353ab6e9	370	mutex_lock(&nlm_host_mutex);
1da177e4 LT	371
	372	/* First, make all hosts eligible for gc */
	373	dprintk("lockd: nuking all hosts...\n");
0cea3276 OK	374	for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
0cea3276 OK	375	hlist_for_each_entry(host, pos, chain, h_hash)
1da177e4 LT	376	host->h_expires = jiffies - 1;
	377	}
	378
	379	/* Then, perform a garbage collection pass */
	380	nlm_gc_hosts();
353ab6e9	381	mutex_unlock(&nlm_host_mutex);
1da177e4 LT	382
	383	/* complain if any hosts are left */
	384	if (nrhosts) {
	385	printk(KERN_WARNING "lockd: couldn't shutdown host module!\n");
	386	dprintk("lockd: %d hosts left:\n", nrhosts);
0cea3276 OK	387	for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
0cea3276 OK	388	hlist_for_each_entry(host, pos, chain, h_hash) {
1da177e4 LT	389	dprintk(" %s (cnt %d use %d exp %ld)\n",
	390	host->h_name, atomic_read(&host->h_count),
	391	host->h_inuse, host->h_expires);
	392	}
	393	}
	394	}
	395	}
	396
	397	/*
	398	* Garbage collect any unused NLM hosts.
	399	* This GC combines reference counting for async operations with
	400	* mark & sweep for resources held by remote clients.
	401	*/
	402	static void
	403	nlm_gc_hosts(void)
	404	{
0cea3276 OK	405	struct hlist_head *chain;
	406	struct hlist_node pos, next;
	407	struct nlm_host *host;
1da177e4 LT	408
1da177e4 LT	409	dprintk("lockd: host garbage collection\n");
0cea3276 OK	410	for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
0cea3276 OK	411	hlist_for_each_entry(host, pos, chain, h_hash)
1da177e4 LT	412	host->h_inuse = 0;
	413	}
	414
	415	/* Mark all hosts that hold locks, blocks or shares */
	416	nlmsvc_mark_resources();
	417
0cea3276 OK	418	for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
0cea3276 OK	419	hlist_for_each_entry_safe(host, pos, next, chain, h_hash) {
1da177e4 LT	420	if (atomic_read(&host->h_count) \|\| host->h_inuse
	421	\|\| time_before(jiffies, host->h_expires)) {
	422	dprintk("nlm_gc_hosts skipping %s (cnt %d use %d exp %ld)\n",
	423	host->h_name, atomic_read(&host->h_count),
	424	host->h_inuse, host->h_expires);
1da177e4 LT	425	continue;
	426	}
	427	dprintk("lockd: delete host %s\n", host->h_name);
0cea3276	428	hlist_del_init(&host->h_hash);
977faf39	429
c53c1bb9	430	nlm_destroy_host(host);
1da177e4 LT	431	nrhosts--;
	432	}
	433	}
	434
	435	next_gc = jiffies + NLM_HOST_COLLECT;
	436	}
	437
8dead0db OK	438
	439	/*
	440	* Manage NSM handles
	441	*/
	442	static LIST_HEAD(nsm_handles);
89e63ef6	443	static DEFINE_MUTEX(nsm_mutex);
8dead0db OK	444
	445	static struct nsm_handle *
	446	__nsm_find(const struct sockaddr_in *sin,
	447	const char *hostname, int hostname_len,
	448	int create)
	449	{
	450	struct nsm_handle *nsm = NULL;
	451	struct list_head *pos;
	452
	453	if (!sin)
	454	return NULL;
	455
	456	if (hostname && memchr(hostname, '/', hostname_len) != NULL) {
	457	if (printk_ratelimit()) {
	458	printk(KERN_WARNING "Invalid hostname \"%.*s\" "
	459	"in NFS lock request\n",
	460	hostname_len, hostname);
	461	}
	462	return NULL;
	463	}
	464
89e63ef6	465	mutex_lock(&nsm_mutex);
8dead0db OK	466	list_for_each(pos, &nsm_handles) {
	467	nsm = list_entry(pos, struct nsm_handle, sm_link);
	468
abd1f500 OK	469	if (hostname && nsm_use_hostnames) {
	470	if (strlen(nsm->sm_name) != hostname_len
	471	\|\| memcmp(nsm->sm_name, hostname, hostname_len))
	472	continue;
	473	} else if (!nlm_cmp_addr(&nsm->sm_addr, sin))
8dead0db OK	474	continue;
	475	atomic_inc(&nsm->sm_count);
	476	goto out;
	477	}
	478
	479	if (!create) {
	480	nsm = NULL;
	481	goto out;
	482	}
	483
	484	nsm = kzalloc(sizeof(*nsm) + hostname_len + 1, GFP_KERNEL);
	485	if (nsm != NULL) {
	486	nsm->sm_addr = *sin;
	487	nsm->sm_name = (char *) (nsm + 1);
	488	memcpy(nsm->sm_name, hostname, hostname_len);
	489	nsm->sm_name[hostname_len] = '\0';
	490	atomic_set(&nsm->sm_count, 1);
	491
	492	list_add(&nsm->sm_link, &nsm_handles);
	493	}
	494
89e63ef6 NB	495	out:
89e63ef6 NB	496	mutex_unlock(&nsm_mutex);
8dead0db OK	497	return nsm;
	498	}
	499
c585646d	500	static struct nsm_handle *
8dead0db OK	501	nsm_find(const struct sockaddr_in sin, const char hostname, int hostname_len)
	502	{
	503	return __nsm_find(sin, hostname, hostname_len, 1);
	504	}
	505
	506	/*
	507	* Release an NSM handle
	508	*/
	509	void
	510	nsm_release(struct nsm_handle *nsm)
	511	{
	512	if (!nsm)
	513	return;
	514	if (atomic_dec_and_test(&nsm->sm_count)) {
89e63ef6	515	mutex_lock(&nsm_mutex);
8dead0db OK	516	if (atomic_read(&nsm->sm_count) == 0) {
	517	list_del(&nsm->sm_link);
	518	kfree(nsm);
	519	}
89e63ef6	520	mutex_unlock(&nsm_mutex);
8dead0db OK	521	}
8dead0db OK	522	}