8c7022eeae65bb99a9b5715393dabca63e5c1af1
[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/lockd/sm_inter.h>
19 #include <linux/mutex.h>
20
21 #include <net/ipv6.h>
22
23 #define NLMDBG_FACILITY         NLMDBG_HOSTCACHE
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         (300 * HZ)
28 #define NLM_HOST_COLLECT        (120 * HZ)
29
30 static struct hlist_head        nlm_hosts[NLM_HOST_NRHASH];
31 static unsigned long            next_gc;
32 static int                      nrhosts;
33 static DEFINE_MUTEX(nlm_host_mutex);
34
35
36 static void                     nlm_gc_hosts(void);
37 static struct nsm_handle *      __nsm_find(const struct sockaddr_in *,
38                                         const char *, unsigned int, int);
39 static struct nsm_handle *      nsm_find(const struct sockaddr_in *sin,
40                                          const char *hostname,
41                                          unsigned int hostname_len);
42
43 static void nlm_clear_port(struct sockaddr *sap)
44 {
45         switch (sap->sa_family) {
46         case AF_INET:
47                 ((struct sockaddr_in *)sap)->sin_port = 0;
48                 break;
49         case AF_INET6:
50                 ((struct sockaddr_in6 *)sap)->sin6_port = 0;
51                 break;
52         }
53 }
54
55 static void nlm_display_address(const struct sockaddr *sap,
56                                 char *buf, const size_t len)
57 {
58         const struct sockaddr_in *sin = (struct sockaddr_in *)sap;
59         const struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sap;
60
61         switch (sap->sa_family) {
62         case AF_UNSPEC:
63                 snprintf(buf, len, "unspecified");
64                 break;
65         case AF_INET:
66                 snprintf(buf, len, NIPQUAD_FMT, NIPQUAD(sin->sin_addr.s_addr));
67                 break;
68         case AF_INET6:
69                 if (ipv6_addr_v4mapped(&sin6->sin6_addr))
70                         snprintf(buf, len, NIPQUAD_FMT,
71                                  NIPQUAD(sin6->sin6_addr.s6_addr32[3]));
72                 else
73                         snprintf(buf, len, NIP6_FMT, NIP6(sin6->sin6_addr));
74                 break;
75         default:
76                 snprintf(buf, len, "unsupported address family");
77                 break;
78         }
79 }
80
81 /*
82  * Common host lookup routine for server & client
83  */
84 static struct nlm_host *nlm_lookup_host(int server,
85                                         const struct sockaddr_in *sin,
86                                         int proto, u32 version,
87                                         const char *hostname,
88                                         unsigned int hostname_len,
89                                         const struct sockaddr_in *ssin)
90 {
91         struct hlist_head *chain;
92         struct hlist_node *pos;
93         struct nlm_host *host;
94         struct nsm_handle *nsm = NULL;
95         int             hash;
96
97         dprintk("lockd: nlm_lookup_host(proto=%d, vers=%u,"
98                         " my role is %s, hostname=%.*s)\n",
99                         proto, version, server ? "server" : "client",
100                         hostname_len, hostname ? hostname : "<none>");
101
102         hash = NLM_ADDRHASH(sin->sin_addr.s_addr);
103
104         /* Lock hash table */
105         mutex_lock(&nlm_host_mutex);
106
107         if (time_after_eq(jiffies, next_gc))
108                 nlm_gc_hosts();
109
110         /* We may keep several nlm_host objects for a peer, because each
111          * nlm_host is identified by
112          * (address, protocol, version, server/client)
113          * We could probably simplify this a little by putting all those
114          * different NLM rpc_clients into one single nlm_host object.
115          * This would allow us to have one nlm_host per address.
116          */
117         chain = &nlm_hosts[hash];
118         hlist_for_each_entry(host, pos, chain, h_hash) {
119                 if (!nlm_cmp_addr(nlm_addr_in(host), sin))
120                         continue;
121
122                 /* See if we have an NSM handle for this client */
123                 if (!nsm)
124                         nsm = host->h_nsmhandle;
125
126                 if (host->h_proto != proto)
127                         continue;
128                 if (host->h_version != version)
129                         continue;
130                 if (host->h_server != server)
131                         continue;
132                 if (!nlm_cmp_addr(&host->h_saddr, ssin))
133                         continue;
134
135                 /* Move to head of hash chain. */
136                 hlist_del(&host->h_hash);
137                 hlist_add_head(&host->h_hash, chain);
138
139                 nlm_get_host(host);
140                 dprintk("lockd: nlm_lookup_host found host %s (%s)\n",
141                                 host->h_name, host->h_addrbuf);
142                 goto out;
143         }
144
145         /*
146          * The host wasn't in our hash table.  If we don't
147          * have an NSM handle for it yet, create one.
148          */
149         if (nsm)
150                 atomic_inc(&nsm->sm_count);
151         else {
152                 host = NULL;
153                 nsm = nsm_find(sin, hostname, hostname_len);
154                 if (!nsm) {
155                         dprintk("lockd: nlm_lookup_host failed; "
156                                 "no nsm handle\n");
157                         goto out;
158                 }
159         }
160
161         host = kzalloc(sizeof(*host), GFP_KERNEL);
162         if (!host) {
163                 nsm_release(nsm);
164                 dprintk("lockd: nlm_lookup_host failed; no memory\n");
165                 goto out;
166         }
167         host->h_name       = nsm->sm_name;
168         memcpy(nlm_addr(host), sin, sizeof(*sin));
169         host->h_addrlen = sizeof(*sin);
170         nlm_clear_port(nlm_addr(host));
171         host->h_saddr      = *ssin;
172         host->h_version    = version;
173         host->h_proto      = proto;
174         host->h_rpcclnt    = NULL;
175         mutex_init(&host->h_mutex);
176         host->h_nextrebind = jiffies + NLM_HOST_REBIND;
177         host->h_expires    = jiffies + NLM_HOST_EXPIRE;
178         atomic_set(&host->h_count, 1);
179         init_waitqueue_head(&host->h_gracewait);
180         init_rwsem(&host->h_rwsem);
181         host->h_state      = 0;                 /* pseudo NSM state */
182         host->h_nsmstate   = 0;                 /* real NSM state */
183         host->h_nsmhandle  = nsm;
184         host->h_server     = server;
185         hlist_add_head(&host->h_hash, chain);
186         INIT_LIST_HEAD(&host->h_lockowners);
187         spin_lock_init(&host->h_lock);
188         INIT_LIST_HEAD(&host->h_granted);
189         INIT_LIST_HEAD(&host->h_reclaim);
190
191         nrhosts++;
192
193         nlm_display_address((struct sockaddr *)&host->h_addr,
194                                 host->h_addrbuf, sizeof(host->h_addrbuf));
195         nlm_display_address((struct sockaddr *)&host->h_saddr,
196                                 host->h_saddrbuf, sizeof(host->h_saddrbuf));
197
198         dprintk("lockd: nlm_lookup_host created host %s\n",
199                         host->h_name);
200
201 out:
202         mutex_unlock(&nlm_host_mutex);
203         return host;
204 }
205
206 /*
207  * Destroy a host
208  */
209 static void
210 nlm_destroy_host(struct nlm_host *host)
211 {
212         struct rpc_clnt *clnt;
213
214         BUG_ON(!list_empty(&host->h_lockowners));
215         BUG_ON(atomic_read(&host->h_count));
216
217         /*
218          * Release NSM handle and unmonitor host.
219          */
220         nsm_unmonitor(host);
221
222         clnt = host->h_rpcclnt;
223         if (clnt != NULL)
224                 rpc_shutdown_client(clnt);
225         kfree(host);
226 }
227
228 /*
229  * Find an NLM server handle in the cache. If there is none, create it.
230  */
231 struct nlm_host *nlmclnt_lookup_host(const struct sockaddr_in *sin,
232                                      int proto, u32 version,
233                                      const char *hostname,
234                                      unsigned int hostname_len)
235 {
236         const struct sockaddr_in source = {
237                 .sin_family     = AF_UNSPEC,
238         };
239
240         return nlm_lookup_host(0, sin, proto, version,
241                                hostname, hostname_len, &source);
242 }
243
244 /*
245  * Find an NLM client handle in the cache. If there is none, create it.
246  */
247 struct nlm_host *
248 nlmsvc_lookup_host(struct svc_rqst *rqstp,
249                         const char *hostname, unsigned int hostname_len)
250 {
251         const struct sockaddr_in source = {
252                 .sin_family     = AF_INET,
253                 .sin_addr       = rqstp->rq_daddr.addr,
254         };
255
256         return nlm_lookup_host(1, svc_addr_in(rqstp),
257                                rqstp->rq_prot, rqstp->rq_vers,
258                                hostname, hostname_len, &source);
259 }
260
261 /*
262  * Create the NLM RPC client for an NLM peer
263  */
264 struct rpc_clnt *
265 nlm_bind_host(struct nlm_host *host)
266 {
267         struct rpc_clnt *clnt;
268
269         dprintk("lockd: nlm_bind_host %s (%s), my addr=%s\n",
270                         host->h_name, host->h_addrbuf, host->h_saddrbuf);
271
272         /* Lock host handle */
273         mutex_lock(&host->h_mutex);
274
275         /* If we've already created an RPC client, check whether
276          * RPC rebind is required
277          */
278         if ((clnt = host->h_rpcclnt) != NULL) {
279                 if (time_after_eq(jiffies, host->h_nextrebind)) {
280                         rpc_force_rebind(clnt);
281                         host->h_nextrebind = jiffies + NLM_HOST_REBIND;
282                         dprintk("lockd: next rebind in %lu jiffies\n",
283                                         host->h_nextrebind - jiffies);
284                 }
285         } else {
286                 unsigned long increment = nlmsvc_timeout;
287                 struct rpc_timeout timeparms = {
288                         .to_initval     = increment,
289                         .to_increment   = increment,
290                         .to_maxval      = increment * 6UL,
291                         .to_retries     = 5U,
292                 };
293                 struct rpc_create_args args = {
294                         .protocol       = host->h_proto,
295                         .address        = nlm_addr(host),
296                         .addrsize       = host->h_addrlen,
297                         .saddress       = (struct sockaddr *)&host->h_saddr,
298                         .timeout        = &timeparms,
299                         .servername     = host->h_name,
300                         .program        = &nlm_program,
301                         .version        = host->h_version,
302                         .authflavor     = RPC_AUTH_UNIX,
303                         .flags          = (RPC_CLNT_CREATE_NOPING |
304                                            RPC_CLNT_CREATE_AUTOBIND),
305                 };
306
307                 /*
308                  * lockd retries server side blocks automatically so we want
309                  * those to be soft RPC calls. Client side calls need to be
310                  * hard RPC tasks.
311                  */
312                 if (!host->h_server)
313                         args.flags |= RPC_CLNT_CREATE_HARDRTRY;
314
315                 clnt = rpc_create(&args);
316                 if (!IS_ERR(clnt))
317                         host->h_rpcclnt = clnt;
318                 else {
319                         printk("lockd: couldn't create RPC handle for %s\n", host->h_name);
320                         clnt = NULL;
321                 }
322         }
323
324         mutex_unlock(&host->h_mutex);
325         return clnt;
326 }
327
328 /*
329  * Force a portmap lookup of the remote lockd port
330  */
331 void
332 nlm_rebind_host(struct nlm_host *host)
333 {
334         dprintk("lockd: rebind host %s\n", host->h_name);
335         if (host->h_rpcclnt && time_after_eq(jiffies, host->h_nextrebind)) {
336                 rpc_force_rebind(host->h_rpcclnt);
337                 host->h_nextrebind = jiffies + NLM_HOST_REBIND;
338         }
339 }
340
341 /*
342  * Increment NLM host count
343  */
344 struct nlm_host * nlm_get_host(struct nlm_host *host)
345 {
346         if (host) {
347                 dprintk("lockd: get host %s\n", host->h_name);
348                 atomic_inc(&host->h_count);
349                 host->h_expires = jiffies + NLM_HOST_EXPIRE;
350         }
351         return host;
352 }
353
354 /*
355  * Release NLM host after use
356  */
357 void nlm_release_host(struct nlm_host *host)
358 {
359         if (host != NULL) {
360                 dprintk("lockd: release host %s\n", host->h_name);
361                 BUG_ON(atomic_read(&host->h_count) < 0);
362                 if (atomic_dec_and_test(&host->h_count)) {
363                         BUG_ON(!list_empty(&host->h_lockowners));
364                         BUG_ON(!list_empty(&host->h_granted));
365                         BUG_ON(!list_empty(&host->h_reclaim));
366                 }
367         }
368 }
369
370 /*
371  * We were notified that the host indicated by address &sin
372  * has rebooted.
373  * Release all resources held by that peer.
374  */
375 void nlm_host_rebooted(const struct sockaddr_in *sin,
376                                 const char *hostname,
377                                 unsigned int hostname_len,
378                                 u32 new_state)
379 {
380         struct hlist_head *chain;
381         struct hlist_node *pos;
382         struct nsm_handle *nsm;
383         struct nlm_host *host;
384
385         /* Find the NSM handle for this peer */
386         nsm = __nsm_find(sin, hostname, hostname_len, 0);
387         if (nsm == NULL) {
388                 dprintk("lockd: never saw rebooted peer '%.*s' before\n",
389                                 hostname_len, hostname);
390                 return;
391         }
392
393         dprintk("lockd: nlm_host_rebooted(%.*s, %s)\n",
394                         hostname_len, hostname, nsm->sm_addrbuf);
395
396         /* When reclaiming locks on this peer, make sure that
397          * we set up a new notification */
398         nsm->sm_monitored = 0;
399
400         /* Mark all hosts tied to this NSM state as having rebooted.
401          * We run the loop repeatedly, because we drop the host table
402          * lock for this.
403          * To avoid processing a host several times, we match the nsmstate.
404          */
405 again:  mutex_lock(&nlm_host_mutex);
406         for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
407                 hlist_for_each_entry(host, pos, chain, h_hash) {
408                         if (host->h_nsmhandle == nsm
409                          && host->h_nsmstate != new_state) {
410                                 host->h_nsmstate = new_state;
411                                 host->h_state++;
412
413                                 nlm_get_host(host);
414                                 mutex_unlock(&nlm_host_mutex);
415
416                                 if (host->h_server) {
417                                         /* We're server for this guy, just ditch
418                                          * all the locks he held. */
419                                         nlmsvc_free_host_resources(host);
420                                 } else {
421                                         /* He's the server, initiate lock recovery. */
422                                         nlmclnt_recovery(host);
423                                 }
424
425                                 nlm_release_host(host);
426                                 goto again;
427                         }
428                 }
429         }
430
431         mutex_unlock(&nlm_host_mutex);
432 }
433
434 /*
435  * Shut down the hosts module.
436  * Note that this routine is called only at server shutdown time.
437  */
438 void
439 nlm_shutdown_hosts(void)
440 {
441         struct hlist_head *chain;
442         struct hlist_node *pos;
443         struct nlm_host *host;
444
445         dprintk("lockd: shutting down host module\n");
446         mutex_lock(&nlm_host_mutex);
447
448         /* First, make all hosts eligible for gc */
449         dprintk("lockd: nuking all hosts...\n");
450         for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
451                 hlist_for_each_entry(host, pos, chain, h_hash) {
452                         host->h_expires = jiffies - 1;
453                         if (host->h_rpcclnt) {
454                                 rpc_shutdown_client(host->h_rpcclnt);
455                                 host->h_rpcclnt = NULL;
456                         }
457                 }
458         }
459
460         /* Then, perform a garbage collection pass */
461         nlm_gc_hosts();
462         mutex_unlock(&nlm_host_mutex);
463
464         /* complain if any hosts are left */
465         if (nrhosts) {
466                 printk(KERN_WARNING "lockd: couldn't shutdown host module!\n");
467                 dprintk("lockd: %d hosts left:\n", nrhosts);
468                 for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
469                         hlist_for_each_entry(host, pos, chain, h_hash) {
470                                 dprintk("       %s (cnt %d use %d exp %ld)\n",
471                                         host->h_name, atomic_read(&host->h_count),
472                                         host->h_inuse, host->h_expires);
473                         }
474                 }
475         }
476 }
477
478 /*
479  * Garbage collect any unused NLM hosts.
480  * This GC combines reference counting for async operations with
481  * mark & sweep for resources held by remote clients.
482  */
483 static void
484 nlm_gc_hosts(void)
485 {
486         struct hlist_head *chain;
487         struct hlist_node *pos, *next;
488         struct nlm_host *host;
489
490         dprintk("lockd: host garbage collection\n");
491         for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
492                 hlist_for_each_entry(host, pos, chain, h_hash)
493                         host->h_inuse = 0;
494         }
495
496         /* Mark all hosts that hold locks, blocks or shares */
497         nlmsvc_mark_resources();
498
499         for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
500                 hlist_for_each_entry_safe(host, pos, next, chain, h_hash) {
501                         if (atomic_read(&host->h_count) || host->h_inuse
502                          || time_before(jiffies, host->h_expires)) {
503                                 dprintk("nlm_gc_hosts skipping %s (cnt %d use %d exp %ld)\n",
504                                         host->h_name, atomic_read(&host->h_count),
505                                         host->h_inuse, host->h_expires);
506                                 continue;
507                         }
508                         dprintk("lockd: delete host %s\n", host->h_name);
509                         hlist_del_init(&host->h_hash);
510
511                         nlm_destroy_host(host);
512                         nrhosts--;
513                 }
514         }
515
516         next_gc = jiffies + NLM_HOST_COLLECT;
517 }
518
519
520 /*
521  * Manage NSM handles
522  */
523 static LIST_HEAD(nsm_handles);
524 static DEFINE_SPINLOCK(nsm_lock);
525
526 static struct nsm_handle *
527 __nsm_find(const struct sockaddr_in *sin,
528                 const char *hostname, unsigned int hostname_len,
529                 int create)
530 {
531         struct nsm_handle *nsm = NULL;
532         struct nsm_handle *pos;
533
534         if (!sin)
535                 return NULL;
536
537         if (hostname && memchr(hostname, '/', hostname_len) != NULL) {
538                 if (printk_ratelimit()) {
539                         printk(KERN_WARNING "Invalid hostname \"%.*s\" "
540                                             "in NFS lock request\n",
541                                 hostname_len, hostname);
542                 }
543                 return NULL;
544         }
545
546 retry:
547         spin_lock(&nsm_lock);
548         list_for_each_entry(pos, &nsm_handles, sm_link) {
549
550                 if (hostname && nsm_use_hostnames) {
551                         if (strlen(pos->sm_name) != hostname_len
552                          || memcmp(pos->sm_name, hostname, hostname_len))
553                                 continue;
554                 } else if (!nlm_cmp_addr(&pos->sm_addr, sin))
555                         continue;
556                 atomic_inc(&pos->sm_count);
557                 kfree(nsm);
558                 nsm = pos;
559                 goto found;
560         }
561         if (nsm) {
562                 list_add(&nsm->sm_link, &nsm_handles);
563                 goto found;
564         }
565         spin_unlock(&nsm_lock);
566
567         if (!create)
568                 return NULL;
569
570         nsm = kzalloc(sizeof(*nsm) + hostname_len + 1, GFP_KERNEL);
571         if (nsm == NULL)
572                 return NULL;
573
574         nsm->sm_addr = *sin;
575         nsm->sm_name = (char *) (nsm + 1);
576         memcpy(nsm->sm_name, hostname, hostname_len);
577         nsm->sm_name[hostname_len] = '\0';
578         nlm_display_address((struct sockaddr *)&nsm->sm_addr,
579                                 nsm->sm_addrbuf, sizeof(nsm->sm_addrbuf));
580         atomic_set(&nsm->sm_count, 1);
581         goto retry;
582
583 found:
584         spin_unlock(&nsm_lock);
585         return nsm;
586 }
587
588 static struct nsm_handle *
589 nsm_find(const struct sockaddr_in *sin, const char *hostname,
590          unsigned int hostname_len)
591 {
592         return __nsm_find(sin, hostname, hostname_len, 1);
593 }
594
595 /*
596  * Release an NSM handle
597  */
598 void
599 nsm_release(struct nsm_handle *nsm)
600 {
601         if (!nsm)
602                 return;
603         if (atomic_dec_and_lock(&nsm->sm_count, &nsm_lock)) {
604                 list_del(&nsm->sm_link);
605                 spin_unlock(&nsm_lock);
606                 kfree(nsm);
607         }
608 }