c6942fb4bd0dea81538da1ef3db05b6340cecaf8
[linux-2.6.git] / fs / lockd / host.c
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/slab.h>
13 #include <linux/in.h>
14 #include <linux/in6.h>
15 #include <linux/sunrpc/clnt.h>
16 #include <linux/sunrpc/svc.h>
17 #include <linux/lockd/lockd.h>
18 #include <linux/mutex.h>
19
20 #include <net/ipv6.h>
21
22 #define NLMDBG_FACILITY         NLMDBG_HOSTCACHE
23 #define NLM_HOST_NRHASH         32
24 #define NLM_HOST_REBIND         (60 * HZ)
25 #define NLM_HOST_EXPIRE         (300 * HZ)
26 #define NLM_HOST_COLLECT        (120 * HZ)
27
28 static struct hlist_head        nlm_hosts[NLM_HOST_NRHASH];
29 static struct hlist_head        nlm_client_hosts[NLM_HOST_NRHASH];
30
31 #define for_each_host(host, pos, chain, table) \
32         for ((chain) = (table); \
33              (chain) < (table) + NLM_HOST_NRHASH; ++(chain)) \
34                 hlist_for_each_entry((host), (pos), (chain), h_hash)
35
36 #define for_each_host_safe(host, pos, next, chain, table) \
37         for ((chain) = (table); \
38              (chain) < (table) + NLM_HOST_NRHASH; ++(chain)) \
39                 hlist_for_each_entry_safe((host), (pos), (next), \
40                                                 (chain), h_hash)
41
42 static unsigned long            next_gc;
43 static int                      nrhosts;
44 static DEFINE_MUTEX(nlm_host_mutex);
45
46 static void                     nlm_gc_hosts(void);
47
48 struct nlm_lookup_host_info {
49         const int               server;         /* search for server|client */
50         const struct sockaddr   *sap;           /* address to search for */
51         const size_t            salen;          /* it's length */
52         const unsigned short    protocol;       /* transport to search for*/
53         const u32               version;        /* NLM version to search for */
54         const char              *hostname;      /* remote's hostname */
55         const size_t            hostname_len;   /* it's length */
56         const struct sockaddr   *src_sap;       /* our address (optional) */
57         const size_t            src_len;        /* it's length */
58         const int               noresvport;     /* use non-priv port */
59 };
60
61 /*
62  * Hash function must work well on big- and little-endian platforms
63  */
64 static unsigned int __nlm_hash32(const __be32 n)
65 {
66         unsigned int hash = (__force u32)n ^ ((__force u32)n >> 16);
67         return hash ^ (hash >> 8);
68 }
69
70 static unsigned int __nlm_hash_addr4(const struct sockaddr *sap)
71 {
72         const struct sockaddr_in *sin = (struct sockaddr_in *)sap;
73         return __nlm_hash32(sin->sin_addr.s_addr);
74 }
75
76 static unsigned int __nlm_hash_addr6(const struct sockaddr *sap)
77 {
78         const struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sap;
79         const struct in6_addr addr = sin6->sin6_addr;
80         return __nlm_hash32(addr.s6_addr32[0]) ^
81                __nlm_hash32(addr.s6_addr32[1]) ^
82                __nlm_hash32(addr.s6_addr32[2]) ^
83                __nlm_hash32(addr.s6_addr32[3]);
84 }
85
86 static unsigned int nlm_hash_address(const struct sockaddr *sap)
87 {
88         unsigned int hash;
89
90         switch (sap->sa_family) {
91         case AF_INET:
92                 hash = __nlm_hash_addr4(sap);
93                 break;
94         case AF_INET6:
95                 hash = __nlm_hash_addr6(sap);
96                 break;
97         default:
98                 hash = 0;
99         }
100         return hash & (NLM_HOST_NRHASH - 1);
101 }
102
103 /*
104  * Allocate and initialize an nlm_host.  Common to both client and server.
105  */
106 static struct nlm_host *nlm_alloc_host(struct nlm_lookup_host_info *ni,
107                                        struct nsm_handle *nsm)
108 {
109         struct nlm_host *host = NULL;
110         unsigned long now = jiffies;
111
112         if (nsm != NULL)
113                 atomic_inc(&nsm->sm_count);
114         else {
115                 host = NULL;
116                 nsm = nsm_get_handle(ni->sap, ni->salen,
117                                         ni->hostname, ni->hostname_len);
118                 if (unlikely(nsm == NULL)) {
119                         dprintk("lockd: %s failed; no nsm handle\n",
120                                 __func__);
121                         goto out;
122                 }
123         }
124
125         host = kmalloc(sizeof(*host), GFP_KERNEL);
126         if (unlikely(host == NULL)) {
127                 dprintk("lockd: %s failed; no memory\n", __func__);
128                 nsm_release(nsm);
129                 goto out;
130         }
131
132         memcpy(nlm_addr(host), ni->sap, ni->salen);
133         host->h_addrlen    = ni->salen;
134         rpc_set_port(nlm_addr(host), 0);
135         host->h_srcaddrlen = 0;
136
137         host->h_rpcclnt    = NULL;
138         host->h_name       = nsm->sm_name;
139         host->h_version    = ni->version;
140         host->h_proto      = ni->protocol;
141         host->h_reclaiming = 0;
142         host->h_server     = ni->server;
143         host->h_noresvport = ni->noresvport;
144         host->h_inuse      = 0;
145         init_waitqueue_head(&host->h_gracewait);
146         init_rwsem(&host->h_rwsem);
147         host->h_state      = 0;
148         host->h_nsmstate   = 0;
149         host->h_pidcount   = 0;
150         atomic_set(&host->h_count, 1);
151         mutex_init(&host->h_mutex);
152         host->h_nextrebind = now + NLM_HOST_REBIND;
153         host->h_expires    = now + NLM_HOST_EXPIRE;
154         INIT_LIST_HEAD(&host->h_lockowners);
155         spin_lock_init(&host->h_lock);
156         INIT_LIST_HEAD(&host->h_granted);
157         INIT_LIST_HEAD(&host->h_reclaim);
158         host->h_nsmhandle  = nsm;
159         host->h_addrbuf    = nsm->sm_addrbuf;
160
161 out:
162         return host;
163 }
164
165 /*
166  * Common host lookup routine for server & client
167  */
168 static struct nlm_host *nlm_lookup_host(struct nlm_lookup_host_info *ni)
169 {
170         struct hlist_head *chain;
171         struct hlist_node *pos;
172         struct nlm_host *host;
173         struct nsm_handle *nsm = NULL;
174
175         mutex_lock(&nlm_host_mutex);
176
177         if (time_after_eq(jiffies, next_gc))
178                 nlm_gc_hosts();
179
180         /* We may keep several nlm_host objects for a peer, because each
181          * nlm_host is identified by
182          * (address, protocol, version, server/client)
183          * We could probably simplify this a little by putting all those
184          * different NLM rpc_clients into one single nlm_host object.
185          * This would allow us to have one nlm_host per address.
186          */
187         chain = &nlm_hosts[nlm_hash_address(ni->sap)];
188         hlist_for_each_entry(host, pos, chain, h_hash) {
189                 if (!rpc_cmp_addr(nlm_addr(host), ni->sap))
190                         continue;
191
192                 /* See if we have an NSM handle for this client */
193                 if (!nsm)
194                         nsm = host->h_nsmhandle;
195
196                 if (host->h_proto != ni->protocol)
197                         continue;
198                 if (host->h_version != ni->version)
199                         continue;
200                 if (host->h_server != ni->server)
201                         continue;
202                 if (ni->server && ni->src_len != 0 &&
203                     !rpc_cmp_addr(nlm_srcaddr(host), ni->src_sap))
204                         continue;
205
206                 /* Move to head of hash chain. */
207                 hlist_del(&host->h_hash);
208                 hlist_add_head(&host->h_hash, chain);
209
210                 nlm_get_host(host);
211                 dprintk("lockd: nlm_lookup_host found host %s (%s)\n",
212                                 host->h_name, host->h_addrbuf);
213                 goto out;
214         }
215
216         host = nlm_alloc_host(ni, nsm);
217         if (unlikely(host == NULL))
218                 goto out;
219
220         memcpy(nlm_srcaddr(host), ni->src_sap, ni->src_len);
221         host->h_srcaddrlen = ni->src_len;
222         hlist_add_head(&host->h_hash, chain);
223
224         nrhosts++;
225
226         dprintk("lockd: nlm_lookup_host created host %s\n",
227                         host->h_name);
228
229 out:
230         mutex_unlock(&nlm_host_mutex);
231         return host;
232 }
233
234 /*
235  * Destroy an nlm_host and free associated resources
236  *
237  * Caller must hold nlm_host_mutex.
238  */
239 static void nlm_destroy_host_locked(struct nlm_host *host)
240 {
241         struct rpc_clnt *clnt;
242
243         dprintk("lockd: destroy host %s\n", host->h_name);
244
245         BUG_ON(!list_empty(&host->h_lockowners));
246         BUG_ON(atomic_read(&host->h_count));
247
248         hlist_del_init(&host->h_hash);
249
250         nsm_unmonitor(host);
251         nsm_release(host->h_nsmhandle);
252
253         clnt = host->h_rpcclnt;
254         if (clnt != NULL)
255                 rpc_shutdown_client(clnt);
256         kfree(host);
257
258         nrhosts--;
259 }
260
261 /**
262  * nlmclnt_lookup_host - Find an NLM host handle matching a remote server
263  * @sap: network address of server
264  * @salen: length of server address
265  * @protocol: transport protocol to use
266  * @version: NLM protocol version
267  * @hostname: '\0'-terminated hostname of server
268  * @noresvport: 1 if non-privileged port should be used
269  *
270  * Returns an nlm_host structure that matches the passed-in
271  * [server address, transport protocol, NLM version, server hostname].
272  * If one doesn't already exist in the host cache, a new handle is
273  * created and returned.
274  */
275 struct nlm_host *nlmclnt_lookup_host(const struct sockaddr *sap,
276                                      const size_t salen,
277                                      const unsigned short protocol,
278                                      const u32 version,
279                                      const char *hostname,
280                                      int noresvport)
281 {
282         struct nlm_lookup_host_info ni = {
283                 .server         = 0,
284                 .sap            = sap,
285                 .salen          = salen,
286                 .protocol       = protocol,
287                 .version        = version,
288                 .hostname       = hostname,
289                 .hostname_len   = strlen(hostname),
290                 .noresvport     = noresvport,
291         };
292         struct hlist_head *chain;
293         struct hlist_node *pos;
294         struct nlm_host *host;
295         struct nsm_handle *nsm = NULL;
296
297         dprintk("lockd: %s(host='%s', vers=%u, proto=%s)\n", __func__,
298                         (hostname ? hostname : "<none>"), version,
299                         (protocol == IPPROTO_UDP ? "udp" : "tcp"));
300
301         mutex_lock(&nlm_host_mutex);
302
303         chain = &nlm_client_hosts[nlm_hash_address(sap)];
304         hlist_for_each_entry(host, pos, chain, h_hash) {
305                 if (!rpc_cmp_addr(nlm_addr(host), sap))
306                         continue;
307
308                 /* Same address. Share an NSM handle if we already have one */
309                 if (nsm == NULL)
310                         nsm = host->h_nsmhandle;
311
312                 if (host->h_proto != protocol)
313                         continue;
314                 if (host->h_version != version)
315                         continue;
316
317                 nlm_get_host(host);
318                 dprintk("lockd: %s found host %s (%s)\n", __func__,
319                         host->h_name, host->h_addrbuf);
320                 goto out;
321         }
322
323         host = nlm_alloc_host(&ni, nsm);
324         if (unlikely(host == NULL))
325                 goto out;
326
327         hlist_add_head(&host->h_hash, chain);
328         nrhosts++;
329
330         dprintk("lockd: %s created host %s (%s)\n", __func__,
331                 host->h_name, host->h_addrbuf);
332
333 out:
334         mutex_unlock(&nlm_host_mutex);
335         return host;
336 }
337
338 /**
339  * nlmclnt_release_host - release client nlm_host
340  * @host: nlm_host to release
341  *
342  */
343 void nlmclnt_release_host(struct nlm_host *host)
344 {
345         if (host == NULL)
346                 return;
347
348         dprintk("lockd: release client host %s\n", host->h_name);
349
350         BUG_ON(atomic_read(&host->h_count) < 0);
351         BUG_ON(host->h_server);
352
353         if (atomic_dec_and_test(&host->h_count)) {
354                 BUG_ON(!list_empty(&host->h_lockowners));
355                 BUG_ON(!list_empty(&host->h_granted));
356                 BUG_ON(!list_empty(&host->h_reclaim));
357
358                 mutex_lock(&nlm_host_mutex);
359                 nlm_destroy_host_locked(host);
360                 mutex_unlock(&nlm_host_mutex);
361         }
362 }
363
364 /**
365  * nlmsvc_lookup_host - Find an NLM host handle matching a remote client
366  * @rqstp: incoming NLM request
367  * @hostname: name of client host
368  * @hostname_len: length of client hostname
369  *
370  * Returns an nlm_host structure that matches the [client address,
371  * transport protocol, NLM version, client hostname] of the passed-in
372  * NLM request.  If one doesn't already exist in the host cache, a
373  * new handle is created and returned.
374  *
375  * Before possibly creating a new nlm_host, construct a sockaddr
376  * for a specific source address in case the local system has
377  * multiple network addresses.  The family of the address in
378  * rq_daddr is guaranteed to be the same as the family of the
379  * address in rq_addr, so it's safe to use the same family for
380  * the source address.
381  */
382 struct nlm_host *nlmsvc_lookup_host(const struct svc_rqst *rqstp,
383                                     const char *hostname,
384                                     const size_t hostname_len)
385 {
386         struct sockaddr_in sin = {
387                 .sin_family     = AF_INET,
388         };
389         struct sockaddr_in6 sin6 = {
390                 .sin6_family    = AF_INET6,
391         };
392         struct nlm_lookup_host_info ni = {
393                 .server         = 1,
394                 .sap            = svc_addr(rqstp),
395                 .salen          = rqstp->rq_addrlen,
396                 .protocol       = rqstp->rq_prot,
397                 .version        = rqstp->rq_vers,
398                 .hostname       = hostname,
399                 .hostname_len   = hostname_len,
400                 .src_len        = rqstp->rq_addrlen,
401         };
402
403         dprintk("lockd: %s(host='%*s', vers=%u, proto=%s)\n", __func__,
404                         (int)hostname_len, hostname, rqstp->rq_vers,
405                         (rqstp->rq_prot == IPPROTO_UDP ? "udp" : "tcp"));
406
407         switch (ni.sap->sa_family) {
408         case AF_INET:
409                 sin.sin_addr.s_addr = rqstp->rq_daddr.addr.s_addr;
410                 ni.src_sap = (struct sockaddr *)&sin;
411                 break;
412         case AF_INET6:
413                 ipv6_addr_copy(&sin6.sin6_addr, &rqstp->rq_daddr.addr6);
414                 ni.src_sap = (struct sockaddr *)&sin6;
415                 break;
416         default:
417                 return NULL;
418         }
419
420         return nlm_lookup_host(&ni);
421 }
422
423 /*
424  * Create the NLM RPC client for an NLM peer
425  */
426 struct rpc_clnt *
427 nlm_bind_host(struct nlm_host *host)
428 {
429         struct rpc_clnt *clnt;
430
431         dprintk("lockd: nlm_bind_host %s (%s)\n",
432                         host->h_name, host->h_addrbuf);
433
434         /* Lock host handle */
435         mutex_lock(&host->h_mutex);
436
437         /* If we've already created an RPC client, check whether
438          * RPC rebind is required
439          */
440         if ((clnt = host->h_rpcclnt) != NULL) {
441                 if (time_after_eq(jiffies, host->h_nextrebind)) {
442                         rpc_force_rebind(clnt);
443                         host->h_nextrebind = jiffies + NLM_HOST_REBIND;
444                         dprintk("lockd: next rebind in %lu jiffies\n",
445                                         host->h_nextrebind - jiffies);
446                 }
447         } else {
448                 unsigned long increment = nlmsvc_timeout;
449                 struct rpc_timeout timeparms = {
450                         .to_initval     = increment,
451                         .to_increment   = increment,
452                         .to_maxval      = increment * 6UL,
453                         .to_retries     = 5U,
454                 };
455                 struct rpc_create_args args = {
456                         .net            = &init_net,
457                         .protocol       = host->h_proto,
458                         .address        = nlm_addr(host),
459                         .addrsize       = host->h_addrlen,
460                         .timeout        = &timeparms,
461                         .servername     = host->h_name,
462                         .program        = &nlm_program,
463                         .version        = host->h_version,
464                         .authflavor     = RPC_AUTH_UNIX,
465                         .flags          = (RPC_CLNT_CREATE_NOPING |
466                                            RPC_CLNT_CREATE_AUTOBIND),
467                 };
468
469                 /*
470                  * lockd retries server side blocks automatically so we want
471                  * those to be soft RPC calls. Client side calls need to be
472                  * hard RPC tasks.
473                  */
474                 if (!host->h_server)
475                         args.flags |= RPC_CLNT_CREATE_HARDRTRY;
476                 if (host->h_noresvport)
477                         args.flags |= RPC_CLNT_CREATE_NONPRIVPORT;
478                 if (host->h_srcaddrlen)
479                         args.saddress = nlm_srcaddr(host);
480
481                 clnt = rpc_create(&args);
482                 if (!IS_ERR(clnt))
483                         host->h_rpcclnt = clnt;
484                 else {
485                         printk("lockd: couldn't create RPC handle for %s\n", host->h_name);
486                         clnt = NULL;
487                 }
488         }
489
490         mutex_unlock(&host->h_mutex);
491         return clnt;
492 }
493
494 /*
495  * Force a portmap lookup of the remote lockd port
496  */
497 void
498 nlm_rebind_host(struct nlm_host *host)
499 {
500         dprintk("lockd: rebind host %s\n", host->h_name);
501         if (host->h_rpcclnt && time_after_eq(jiffies, host->h_nextrebind)) {
502                 rpc_force_rebind(host->h_rpcclnt);
503                 host->h_nextrebind = jiffies + NLM_HOST_REBIND;
504         }
505 }
506
507 /*
508  * Increment NLM host count
509  */
510 struct nlm_host * nlm_get_host(struct nlm_host *host)
511 {
512         if (host) {
513                 dprintk("lockd: get host %s\n", host->h_name);
514                 atomic_inc(&host->h_count);
515                 host->h_expires = jiffies + NLM_HOST_EXPIRE;
516         }
517         return host;
518 }
519
520 /*
521  * Release NLM host after use
522  */
523 void nlm_release_host(struct nlm_host *host)
524 {
525         if (host != NULL) {
526                 dprintk("lockd: release host %s\n", host->h_name);
527                 BUG_ON(atomic_read(&host->h_count) < 0);
528                 if (atomic_dec_and_test(&host->h_count)) {
529                         BUG_ON(!list_empty(&host->h_lockowners));
530                         BUG_ON(!list_empty(&host->h_granted));
531                         BUG_ON(!list_empty(&host->h_reclaim));
532                 }
533         }
534 }
535
536 static struct nlm_host *next_host_state(struct hlist_head *cache,
537                                         struct nsm_handle *nsm,
538                                         const struct nlm_reboot *info)
539 {
540         struct nlm_host *host = NULL;
541         struct hlist_head *chain;
542         struct hlist_node *pos;
543
544         mutex_lock(&nlm_host_mutex);
545         for_each_host(host, pos, chain, cache) {
546                 if (host->h_nsmhandle == nsm
547                     && host->h_nsmstate != info->state) {
548                         host->h_nsmstate = info->state;
549                         host->h_state++;
550
551                         nlm_get_host(host);
552                         mutex_unlock(&nlm_host_mutex);
553                         goto out;
554                 }
555         }
556 out:
557         mutex_unlock(&nlm_host_mutex);
558         return host;
559 }
560
561 /**
562  * nlm_host_rebooted - Release all resources held by rebooted host
563  * @info: pointer to decoded results of NLM_SM_NOTIFY call
564  *
565  * We were notified that the specified host has rebooted.  Release
566  * all resources held by that peer.
567  */
568 void nlm_host_rebooted(const struct nlm_reboot *info)
569 {
570         struct nsm_handle *nsm;
571         struct nlm_host *host;
572
573         nsm = nsm_reboot_lookup(info);
574         if (unlikely(nsm == NULL))
575                 return;
576
577         /* Mark all hosts tied to this NSM state as having rebooted.
578          * We run the loop repeatedly, because we drop the host table
579          * lock for this.
580          * To avoid processing a host several times, we match the nsmstate.
581          */
582         while ((host = next_host_state(nlm_hosts, nsm, info)) != NULL) {
583                 nlmsvc_free_host_resources(host);
584                 nlm_release_host(host);
585         }
586         while ((host = next_host_state(nlm_client_hosts, nsm, info)) != NULL) {
587                 nlmclnt_recovery(host);
588                 nlmclnt_release_host(host);
589         }
590
591         nsm_release(nsm);
592 }
593
594 /*
595  * Shut down the hosts module.
596  * Note that this routine is called only at server shutdown time.
597  */
598 void
599 nlm_shutdown_hosts(void)
600 {
601         struct hlist_head *chain;
602         struct hlist_node *pos;
603         struct nlm_host *host;
604
605         dprintk("lockd: shutting down host module\n");
606         mutex_lock(&nlm_host_mutex);
607
608         /* First, make all hosts eligible for gc */
609         dprintk("lockd: nuking all hosts...\n");
610         for_each_host(host, pos, chain, nlm_hosts) {
611                 host->h_expires = jiffies - 1;
612                 if (host->h_rpcclnt) {
613                         rpc_shutdown_client(host->h_rpcclnt);
614                         host->h_rpcclnt = NULL;
615                 }
616         }
617
618         /* Then, perform a garbage collection pass */
619         nlm_gc_hosts();
620         mutex_unlock(&nlm_host_mutex);
621
622         /* complain if any hosts are left */
623         if (nrhosts) {
624                 printk(KERN_WARNING "lockd: couldn't shutdown host module!\n");
625                 dprintk("lockd: %d hosts left:\n", nrhosts);
626                 for_each_host(host, pos, chain, nlm_hosts) {
627                         dprintk("       %s (cnt %d use %d exp %ld)\n",
628                                 host->h_name, atomic_read(&host->h_count),
629                                 host->h_inuse, host->h_expires);
630                 }
631         }
632 }
633
634 /*
635  * Garbage collect any unused NLM hosts.
636  * This GC combines reference counting for async operations with
637  * mark & sweep for resources held by remote clients.
638  */
639 static void
640 nlm_gc_hosts(void)
641 {
642         struct hlist_head *chain;
643         struct hlist_node *pos, *next;
644         struct nlm_host *host;
645
646         dprintk("lockd: host garbage collection\n");
647         for_each_host(host, pos, chain, nlm_hosts)
648                 host->h_inuse = 0;
649
650         /* Mark all hosts that hold locks, blocks or shares */
651         nlmsvc_mark_resources();
652
653         for_each_host_safe(host, pos, next, chain, nlm_hosts) {
654                 if (atomic_read(&host->h_count) || host->h_inuse
655                  || time_before(jiffies, host->h_expires)) {
656                         dprintk("nlm_gc_hosts skipping %s "
657                                 "(cnt %d use %d exp %ld)\n",
658                                 host->h_name, atomic_read(&host->h_count),
659                                 host->h_inuse, host->h_expires);
660                         continue;
661                 }
662                 nlm_destroy_host_locked(host);
663         }
664
665         next_gc = jiffies + NLM_HOST_COLLECT;
666 }