host.c 12.7 KB
Newer Older
L
Linus Torvalds 已提交
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17
/*
 * 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>
I
Ingo Molnar 已提交
18
#include <linux/mutex.h>
L
Linus Torvalds 已提交
19 20 21 22 23 24 25 26 27 28


#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)

29
static struct hlist_head	nlm_hosts[NLM_HOST_NRHASH];
L
Linus Torvalds 已提交
30 31
static unsigned long		next_gc;
static int			nrhosts;
I
Ingo Molnar 已提交
32
static DEFINE_MUTEX(nlm_host_mutex);
L
Linus Torvalds 已提交
33 34 35


static void			nlm_gc_hosts(void);
36 37
static struct nsm_handle *	__nsm_find(const struct sockaddr_in *,
					const char *, int, int);
38 39 40
static struct nsm_handle *	nsm_find(const struct sockaddr_in *sin,
					 const char *hostname,
					 int hostname_len);
L
Linus Torvalds 已提交
41 42 43 44

/*
 * Common host lookup routine for server & client
 */
45
static struct nlm_host *
46
nlm_lookup_host(int server, const struct sockaddr_in *sin,
47 48 49
					int proto, int version,
					const char *hostname,
					int hostname_len)
L
Linus Torvalds 已提交
50
{
51 52 53
	struct hlist_head *chain;
	struct hlist_node *pos;
	struct nlm_host	*host;
54
	struct nsm_handle *nsm = NULL;
L
Linus Torvalds 已提交
55 56
	int		hash;

57 58 59 60 61 62
	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>");

L
Linus Torvalds 已提交
63 64 65 66

	hash = NLM_ADDRHASH(sin->sin_addr.s_addr);

	/* Lock hash table */
I
Ingo Molnar 已提交
67
	mutex_lock(&nlm_host_mutex);
L
Linus Torvalds 已提交
68 69 70 71

	if (time_after_eq(jiffies, next_gc))
		nlm_gc_hosts();

72 73 74 75 76 77 78
	/* 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.
	 */
79 80
	chain = &nlm_hosts[hash];
	hlist_for_each_entry(host, pos, chain, h_hash) {
81 82 83 84
		if (!nlm_cmp_addr(&host->h_addr, sin))
			continue;

		/* See if we have an NSM handle for this client */
85 86
		if (!nsm)
			nsm = host->h_nsmhandle;
87

L
Linus Torvalds 已提交
88 89 90 91 92 93 94
		if (host->h_proto != proto)
			continue;
		if (host->h_version != version)
			continue;
		if (host->h_server != server)
			continue;

95 96 97 98
		/* Move to head of hash chain. */
		hlist_del(&host->h_hash);
		hlist_add_head(&host->h_hash, chain);

99 100
		nlm_get_host(host);
		goto out;
L
Linus Torvalds 已提交
101
	}
102 103
	if (nsm)
		atomic_inc(&nsm->sm_count);
L
Linus Torvalds 已提交
104

105 106
	host = NULL;

107 108 109 110 111
	/* 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;
L
Linus Torvalds 已提交
112

113
	host = kzalloc(sizeof(*host), GFP_KERNEL);
114 115 116 117 118
	if (!host) {
		nsm_release(nsm);
		goto out;
	}
	host->h_name	   = nsm->sm_name;
L
Linus Torvalds 已提交
119 120 121 122 123
	host->h_addr       = *sin;
	host->h_addr.sin_port = 0;	/* ouch! */
	host->h_version    = version;
	host->h_proto      = proto;
	host->h_rpcclnt    = NULL;
T
Trond Myklebust 已提交
124
	mutex_init(&host->h_mutex);
L
Linus Torvalds 已提交
125 126 127 128
	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);
T
Trond Myklebust 已提交
129
	init_rwsem(&host->h_rwsem);
L
Linus Torvalds 已提交
130 131
	host->h_state      = 0;			/* pseudo NSM state */
	host->h_nsmstate   = 0;			/* real NSM state */
132
	host->h_nsmhandle  = nsm;
L
Linus Torvalds 已提交
133
	host->h_server	   = server;
134
	hlist_add_head(&host->h_hash, chain);
L
Linus Torvalds 已提交
135 136
	INIT_LIST_HEAD(&host->h_lockowners);
	spin_lock_init(&host->h_lock);
137 138
	INIT_LIST_HEAD(&host->h_granted);
	INIT_LIST_HEAD(&host->h_reclaim);
L
Linus Torvalds 已提交
139 140 141 142

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

143
out:
I
Ingo Molnar 已提交
144
	mutex_unlock(&nlm_host_mutex);
L
Linus Torvalds 已提交
145 146 147
	return host;
}

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
/*
 * 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);
}

176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193
/*
 * 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)
{
194
	return nlm_lookup_host(1, svc_addr_in(rqstp),
195 196 197 198
			       rqstp->rq_prot, rqstp->rq_vers,
			       hostname, hostname_len);
}

L
Linus Torvalds 已提交
199 200 201 202 203 204 205 206 207 208 209 210
/*
 * 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 */
T
Trond Myklebust 已提交
211
	mutex_lock(&host->h_mutex);
L
Linus Torvalds 已提交
212 213 214 215 216

	/* If we've already created an RPC client, check whether
	 * RPC rebind is required
	 */
	if ((clnt = host->h_rpcclnt) != NULL) {
217
		if (time_after_eq(jiffies, host->h_nextrebind)) {
218
			rpc_force_rebind(clnt);
L
Linus Torvalds 已提交
219 220 221 222 223
			host->h_nextrebind = jiffies + NLM_HOST_REBIND;
			dprintk("lockd: next rebind in %ld jiffies\n",
					host->h_nextrebind - jiffies);
		}
	} else {
224
		unsigned long increment = nlmsvc_timeout;
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
		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;
		}
L
Linus Torvalds 已提交
251 252
	}

T
Trond Myklebust 已提交
253
	mutex_unlock(&host->h_mutex);
L
Linus Torvalds 已提交
254 255 256 257 258 259 260 261 262 263 264
	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)) {
265
		rpc_force_rebind(host->h_rpcclnt);
L
Linus Torvalds 已提交
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
		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);
291 292 293 294 295
		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));
		}
L
Linus Torvalds 已提交
296 297 298
	}
}

299 300 301 302 303
/*
 * We were notified that the host indicated by address &sin
 * has rebooted.
 * Release all resources held by that peer.
 */
304 305 306
void nlm_host_rebooted(const struct sockaddr_in *sin,
				const char *hostname, int hostname_len,
				u32 new_state)
307
{
308 309
	struct hlist_head *chain;
	struct hlist_node *pos;
310
	struct nsm_handle *nsm;
311
	struct nlm_host	*host;
312

313 314 315 316 317
	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)))
318 319
		return;

320 321 322 323 324 325 326 327 328 329
	/* 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);
330 331
	for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
		hlist_for_each_entry(host, pos, chain, h_hash) {
332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352
			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;
			}
		}
353
	}
354 355

	mutex_unlock(&nlm_host_mutex);
356 357
}

L
Linus Torvalds 已提交
358 359 360 361 362 363 364
/*
 * Shut down the hosts module.
 * Note that this routine is called only at server shutdown time.
 */
void
nlm_shutdown_hosts(void)
{
365 366
	struct hlist_head *chain;
	struct hlist_node *pos;
L
Linus Torvalds 已提交
367 368 369
	struct nlm_host	*host;

	dprintk("lockd: shutting down host module\n");
I
Ingo Molnar 已提交
370
	mutex_lock(&nlm_host_mutex);
L
Linus Torvalds 已提交
371 372 373

	/* First, make all hosts eligible for gc */
	dprintk("lockd: nuking all hosts...\n");
374 375
	for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
		hlist_for_each_entry(host, pos, chain, h_hash)
L
Linus Torvalds 已提交
376 377 378 379 380
			host->h_expires = jiffies - 1;
	}

	/* Then, perform a garbage collection pass */
	nlm_gc_hosts();
I
Ingo Molnar 已提交
381
	mutex_unlock(&nlm_host_mutex);
L
Linus Torvalds 已提交
382 383 384 385 386

	/* 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);
387 388
		for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
			hlist_for_each_entry(host, pos, chain, h_hash) {
L
Linus Torvalds 已提交
389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404
				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)
{
405 406 407
	struct hlist_head *chain;
	struct hlist_node *pos, *next;
	struct nlm_host	*host;
L
Linus Torvalds 已提交
408 409

	dprintk("lockd: host garbage collection\n");
410 411
	for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
		hlist_for_each_entry(host, pos, chain, h_hash)
L
Linus Torvalds 已提交
412 413 414 415 416 417
			host->h_inuse = 0;
	}

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

418 419
	for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
		hlist_for_each_entry_safe(host, pos, next, chain, h_hash) {
L
Linus Torvalds 已提交
420 421 422 423 424 425 426 427
			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);
428
			hlist_del_init(&host->h_hash);
429

430
			nlm_destroy_host(host);
L
Linus Torvalds 已提交
431 432 433 434 435 436 437
			nrhosts--;
		}
	}

	next_gc = jiffies + NLM_HOST_COLLECT;
}

438 439 440 441 442

/*
 * Manage NSM handles
 */
static LIST_HEAD(nsm_handles);
443
static DEFINE_MUTEX(nsm_mutex);
444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464

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;
	}

465
	mutex_lock(&nsm_mutex);
466 467 468
	list_for_each(pos, &nsm_handles) {
		nsm = list_entry(pos, struct nsm_handle, sm_link);

469 470 471 472 473
		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))
474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494
			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);
	}

495 496
out:
	mutex_unlock(&nsm_mutex);
497 498 499
	return nsm;
}

500
static struct nsm_handle *
501 502 503 504 505 506 507 508 509 510 511 512 513 514
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)) {
515
		mutex_lock(&nsm_mutex);
516 517 518 519
		if (atomic_read(&nsm->sm_count) == 0) {
			list_del(&nsm->sm_link);
			kfree(nsm);
		}
520
		mutex_unlock(&nsm_mutex);
521 522
	}
}