summaryrefslogtreecommitdiffstats
path: root/fs/lockd/host.c
blob: 90a62f27914c737757937e68dedf5f6abe0e7823 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
/*
 * 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>


#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 DECLARE_MUTEX(nlm_host_sema);


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 */
	down(&nlm_host_sema);

	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);
			up(&nlm_host_sema);
			return host;
		}
	}

	/* Ooops, no host found, create it */
	dprintk("lockd: creating host entry\n");

	if (!(host = (struct nlm_host *) kmalloc(sizeof(*host), GFP_KERNEL)))
		goto nohost;
	memset(host, 0, sizeof(*host));

	addr = sin->sin_addr.s_addr;
	sprintf(host->h_name, "%u.%u.%u.%u", NIPQUAD(addr));

	host->h_addr       = *sin;
	host->h_addr.sin_port = 0;	/* ouch! */
	host->h_version    = version;
	host->h_proto      = proto;
	host->h_rpcclnt    = NULL;
	init_MUTEX(&host->h_sema);
	host->h_nextrebind = jiffies + NLM_HOST_REBIND;
	host->h_expires    = jiffies + NLM_HOST_EXPIRE;
	atomic_set(&host->h_count, 1);
	init_waitqueue_head(&host->h_gracewait);
	host->h_state      = 0;			/* pseudo NSM state */
	host->h_nsmstate   = 0;			/* real NSM state */
	host->h_server	   = server;
	host->h_next       = nlm_hosts[hash];
	nlm_hosts[hash]    = host;
	INIT_LIST_HEAD(&host->h_lockowners);
	spin_lock_init(&host->h_lock);

	if (++nrhosts > NLM_HOST_MAX)
		next_gc = 0;

nohost:
	up(&nlm_host_sema);
	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;
	down(&nlm_host_sema);
	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);
				up(&nlm_host_sema);
				return host;
			}
		}
	}
	up(&nlm_host_sema);
	return NULL;
}

				
/*
 * Create the NLM RPC client for an NLM peer
 */
struct rpc_clnt *
nlm_bind_host(struct nlm_host *host)
{
	struct rpc_clnt	*clnt;
	struct rpc_xprt	*xprt;

	dprintk("lockd: nlm_bind_host(%08x)\n",
			(unsigned)ntohl(host->h_addr.sin_addr.s_addr));

	/* Lock host handle */
	down(&host->h_sema);

	/* If we've already created an RPC client, check whether
	 * RPC rebind is required
	 * Note: why keep rebinding if we're on a tcp connection?
	 */
	if ((clnt = host->h_rpcclnt) != NULL) {
		xprt = clnt->cl_xprt;
		if (!xprt->stream && time_after_eq(jiffies, host->h_nextrebind)) {
			clnt->cl_port = 0;
			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);

		/* Existing NLM servers accept AUTH_UNIX only */
		clnt = rpc_create_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 */
		xprt->nocong = 1;	/* No congestion control for NLM */
		xprt->resvport = 1;	/* NLM requires a reserved port */

		host->h_rpcclnt = clnt;
	}

	up(&host->h_sema);
	return clnt;

forgetit:
	printk("lockd: couldn't create RPC handle for %s\n", host->h_name);
	up(&host->h_sema);
	return NULL;
}

/*
 * Force a portmap lookup of the remote lockd port
 */
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)) {
		host->h_rpcclnt->cl_port = 0;
		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);
		atomic_dec(&host->h_count);
		BUG_ON(atomic_read(&host->h_count) < 0);
	}
}

/*
 * 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");
	down(&nlm_host_sema);

	/* 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();
	up(&nlm_host_sema);

	/* 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);
				}
			}
			BUG_ON(!list_empty(&host->h_lockowners));
			kfree(host);
			nrhosts--;
		}
	}

	next_gc = jiffies + NLM_HOST_COLLECT;
}