Merge branch 'for-2.6.31' of git://fieldses.org/git/linux-nfsd
[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 unsigned long            next_gc;
30 static int                      nrhosts;
31 static DEFINE_MUTEX(nlm_host_mutex);
32
33 static void                     nlm_gc_hosts(void);
34
35 struct nlm_lookup_host_info {
36         const int               server;         /* search for server|client */
37         const struct sockaddr   *sap;           /* address to search for */
38         const size_t            salen;          /* it's length */
39         const unsigned short    protocol;       /* transport to search for*/
40         const u32               version;        /* NLM version to search for */
41         const char              *hostname;      /* remote's hostname */
42         const size_t            hostname_len;   /* it's length */
43         const struct sockaddr   *src_sap;       /* our address (optional) */
44         const size_t            src_len;        /* it's length */
45         const int               noresvport;     /* use non-priv port */
46 };
47
48 /*
49  * Hash function must work well on big- and little-endian platforms
50  */
51 static unsigned int __nlm_hash32(const __be32 n)
52 {
53         unsigned int hash = (__force u32)n ^ ((__force u32)n >> 16);
54         return hash ^ (hash >> 8);
55 }
56
57 static unsigned int __nlm_hash_addr4(const struct sockaddr *sap)
58 {
59         const struct sockaddr_in *sin = (struct sockaddr_in *)sap;
60         return __nlm_hash32(sin->sin_addr.s_addr);
61 }
62
63 static unsigned int __nlm_hash_addr6(const struct sockaddr *sap)
64 {
65         const struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sap;
66         const struct in6_addr addr = sin6->sin6_addr;
67         return __nlm_hash32(addr.s6_addr32[0]) ^
68                __nlm_hash32(addr.s6_addr32[1]) ^
69                __nlm_hash32(addr.s6_addr32[2]) ^
70                __nlm_hash32(addr.s6_addr32[3]);
71 }
72
73 static unsigned int nlm_hash_address(const struct sockaddr *sap)
74 {
75         unsigned int hash;
76
77         switch (sap->sa_family) {
78         case AF_INET:
79                 hash = __nlm_hash_addr4(sap);
80                 break;
81         case AF_INET6:
82                 hash = __nlm_hash_addr6(sap);
83                 break;
84         default:
85                 hash = 0;
86         }
87         return hash & (NLM_HOST_NRHASH - 1);
88 }
89
90 static void nlm_clear_port(struct sockaddr *sap)
91 {
92         switch (sap->sa_family) {
93         case AF_INET:
94                 ((struct sockaddr_in *)sap)->sin_port = 0;
95                 break;
96         case AF_INET6:
97                 ((struct sockaddr_in6 *)sap)->sin6_port = 0;
98                 break;
99         }
100 }
101
102 /*
103  * Common host lookup routine for server & client
104  */
105 static struct nlm_host *nlm_lookup_host(struct nlm_lookup_host_info *ni)
106 {
107         struct hlist_head *chain;
108         struct hlist_node *pos;
109         struct nlm_host *host;
110         struct nsm_handle *nsm = NULL;
111
112         mutex_lock(&nlm_host_mutex);
113
114         if (time_after_eq(jiffies, next_gc))
115                 nlm_gc_hosts();
116
117         /* We may keep several nlm_host objects for a peer, because each
118          * nlm_host is identified by
119          * (address, protocol, version, server/client)
120          * We could probably simplify this a little by putting all those
121          * different NLM rpc_clients into one single nlm_host object.
122          * This would allow us to have one nlm_host per address.
123          */
124         chain = &nlm_hosts[nlm_hash_address(ni->sap)];
125         hlist_for_each_entry(host, pos, chain, h_hash) {
126                 if (!nlm_cmp_addr(nlm_addr(host), ni->sap))
127                         continue;
128
129                 /* See if we have an NSM handle for this client */
130                 if (!nsm)
131                         nsm = host->h_nsmhandle;
132
133                 if (host->h_proto != ni->protocol)
134                         continue;
135                 if (host->h_version != ni->version)
136                         continue;
137                 if (host->h_server != ni->server)
138                         continue;
139                 if (ni->server &&
140                     !nlm_cmp_addr(nlm_srcaddr(host), ni->src_sap))
141                         continue;
142
143                 /* Move to head of hash chain. */
144                 hlist_del(&host->h_hash);
145                 hlist_add_head(&host->h_hash, chain);
146
147                 nlm_get_host(host);
148                 dprintk("lockd: nlm_lookup_host found host %s (%s)\n",
149                                 host->h_name, host->h_addrbuf);
150                 goto out;
151         }
152
153         /*
154          * The host wasn't in our hash table.  If we don't
155          * have an NSM handle for it yet, create one.
156          */
157         if (nsm)
158                 atomic_inc(&nsm->sm_count);
159         else {
160                 host = NULL;
161                 nsm = nsm_get_handle(ni->sap, ni->salen,
162                                         ni->hostname, ni->hostname_len);
163                 if (!nsm) {
164                         dprintk("lockd: nlm_lookup_host failed; "
165                                 "no nsm handle\n");
166                         goto out;
167                 }
168         }
169
170         host = kzalloc(sizeof(*host), GFP_KERNEL);
171         if (!host) {
172                 nsm_release(nsm);
173                 dprintk("lockd: nlm_lookup_host failed; no memory\n");
174                 goto out;
175         }
176         host->h_name       = nsm->sm_name;
177         host->h_addrbuf    = nsm->sm_addrbuf;
178         memcpy(nlm_addr(host), ni->sap, ni->salen);
179         host->h_addrlen = ni->salen;
180         nlm_clear_port(nlm_addr(host));
181         memcpy(nlm_srcaddr(host), ni->src_sap, ni->src_len);
182         host->h_version    = ni->version;
183         host->h_proto      = ni->protocol;
184         host->h_rpcclnt    = NULL;
185         mutex_init(&host->h_mutex);
186         host->h_nextrebind = jiffies + NLM_HOST_REBIND;
187         host->h_expires    = jiffies + NLM_HOST_EXPIRE;
188         atomic_set(&host->h_count, 1);
189         init_waitqueue_head(&host->h_gracewait);
190         init_rwsem(&host->h_rwsem);
191         host->h_state      = 0;                 /* pseudo NSM state */
192         host->h_nsmstate   = 0;                 /* real NSM state */
193         host->h_nsmhandle  = nsm;
194         host->h_server     = ni->server;
195         host->h_noresvport = ni->noresvport;
196         hlist_add_head(&host->h_hash, chain);
197         INIT_LIST_HEAD(&host->h_lockowners);
198         spin_lock_init(&host->h_lock);
199         INIT_LIST_HEAD(&host->h_granted);
200         INIT_LIST_HEAD(&host->h_reclaim);
201
202         nrhosts++;
203
204         dprintk("lockd: nlm_lookup_host created host %s\n",
205                         host->h_name);
206
207 out:
208         mutex_unlock(&nlm_host_mutex);
209         return host;
210 }
211
212 /*
213  * Destroy a host
214  */
215 static void
216 nlm_destroy_host(struct nlm_host *host)
217 {
218         struct rpc_clnt *clnt;
219
220         BUG_ON(!list_empty(&host->h_lockowners));
221         BUG_ON(atomic_read(&host->h_count));
222
223         nsm_unmonitor(host);
224         nsm_release(host->h_nsmhandle);
225
226         clnt = host->h_rpcclnt;
227         if (clnt != NULL)
228                 rpc_shutdown_client(clnt);
229         kfree(host);
230 }
231
232 /**
233  * nlmclnt_lookup_host - Find an NLM host handle matching a remote server
234  * @sap: network address of server
235  * @salen: length of server address
236  * @protocol: transport protocol to use
237  * @version: NLM protocol version
238  * @hostname: '\0'-terminated hostname of server
239  * @noresvport: 1 if non-privileged port should be used
240  *
241  * Returns an nlm_host structure that matches the passed-in
242  * [server address, transport protocol, NLM version, server hostname].
243  * If one doesn't already exist in the host cache, a new handle is
244  * created and returned.
245  */
246 struct nlm_host *nlmclnt_lookup_host(const struct sockaddr *sap,
247                                      const size_t salen,
248                                      const unsigned short protocol,
249                                      const u32 version,
250                                      const char *hostname,
251                                      int noresvport)
252 {
253         const struct sockaddr source = {
254                 .sa_family      = AF_UNSPEC,
255         };
256         struct nlm_lookup_host_info ni = {
257                 .server         = 0,
258                 .sap            = sap,
259                 .salen          = salen,
260                 .protocol       = protocol,
261                 .version        = version,
262                 .hostname       = hostname,
263                 .hostname_len   = strlen(hostname),
264                 .src_sap        = &source,
265                 .src_len        = sizeof(source),
266                 .noresvport     = noresvport,
267         };
268
269         dprintk("lockd: %s(host='%s', vers=%u, proto=%s)\n", __func__,
270                         (hostname ? hostname : "<none>"), version,
271                         (protocol == IPPROTO_UDP ? "udp" : "tcp"));
272
273         return nlm_lookup_host(&ni);
274 }
275
276 /**
277  * nlmsvc_lookup_host - Find an NLM host handle matching a remote client
278  * @rqstp: incoming NLM request
279  * @hostname: name of client host
280  * @hostname_len: length of client hostname
281  *
282  * Returns an nlm_host structure that matches the [client address,
283  * transport protocol, NLM version, client hostname] of the passed-in
284  * NLM request.  If one doesn't already exist in the host cache, a
285  * new handle is created and returned.
286  *
287  * Before possibly creating a new nlm_host, construct a sockaddr
288  * for a specific source address in case the local system has
289  * multiple network addresses.  The family of the address in
290  * rq_daddr is guaranteed to be the same as the family of the
291  * address in rq_addr, so it's safe to use the same family for
292  * the source address.
293  */
294 struct nlm_host *nlmsvc_lookup_host(const struct svc_rqst *rqstp,
295                                     const char *hostname,
296                                     const size_t hostname_len)
297 {
298         struct sockaddr_in sin = {
299                 .sin_family     = AF_INET,
300         };
301         struct sockaddr_in6 sin6 = {
302                 .sin6_family    = AF_INET6,
303         };
304         struct nlm_lookup_host_info ni = {
305                 .server         = 1,
306                 .sap            = svc_addr(rqstp),
307                 .salen          = rqstp->rq_addrlen,
308                 .protocol       = rqstp->rq_prot,
309                 .version        = rqstp->rq_vers,
310                 .hostname       = hostname,
311                 .hostname_len   = hostname_len,
312                 .src_len        = rqstp->rq_addrlen,
313         };
314
315         dprintk("lockd: %s(host='%*s', vers=%u, proto=%s)\n", __func__,
316                         (int)hostname_len, hostname, rqstp->rq_vers,
317                         (rqstp->rq_prot == IPPROTO_UDP ? "udp" : "tcp"));
318
319         switch (ni.sap->sa_family) {
320         case AF_INET:
321                 sin.sin_addr.s_addr = rqstp->rq_daddr.addr.s_addr;
322                 ni.src_sap = (struct sockaddr *)&sin;
323                 break;
324         case AF_INET6:
325                 ipv6_addr_copy(&sin6.sin6_addr, &rqstp->rq_daddr.addr6);
326                 ni.src_sap = (struct sockaddr *)&sin6;
327                 break;
328         default:
329                 return NULL;
330         }
331
332         return nlm_lookup_host(&ni);
333 }
334
335 /*
336  * Create the NLM RPC client for an NLM peer
337  */
338 struct rpc_clnt *
339 nlm_bind_host(struct nlm_host *host)
340 {
341         struct rpc_clnt *clnt;
342
343         dprintk("lockd: nlm_bind_host %s (%s)\n",
344                         host->h_name, host->h_addrbuf);
345
346         /* Lock host handle */
347         mutex_lock(&host->h_mutex);
348
349         /* If we've already created an RPC client, check whether
350          * RPC rebind is required
351          */
352         if ((clnt = host->h_rpcclnt) != NULL) {
353                 if (time_after_eq(jiffies, host->h_nextrebind)) {
354                         rpc_force_rebind(clnt);
355                         host->h_nextrebind = jiffies + NLM_HOST_REBIND;
356                         dprintk("lockd: next rebind in %lu jiffies\n",
357                                         host->h_nextrebind - jiffies);
358                 }
359         } else {
360                 unsigned long increment = nlmsvc_timeout;
361                 struct rpc_timeout timeparms = {
362                         .to_initval     = increment,
363                         .to_increment   = increment,
364                         .to_maxval      = increment * 6UL,
365                         .to_retries     = 5U,
366                 };
367                 struct rpc_create_args args = {
368                         .protocol       = host->h_proto,
369                         .address        = nlm_addr(host),
370                         .addrsize       = host->h_addrlen,
371                         .saddress       = nlm_srcaddr(host),
372                         .timeout        = &timeparms,
373                         .servername     = host->h_name,
374                         .program        = &nlm_program,
375                         .version        = host->h_version,
376                         .authflavor     = RPC_AUTH_UNIX,
377                         .flags          = (RPC_CLNT_CREATE_NOPING |
378                                            RPC_CLNT_CREATE_AUTOBIND),
379                 };
380
381                 /*
382                  * lockd retries server side blocks automatically so we want
383                  * those to be soft RPC calls. Client side calls need to be
384                  * hard RPC tasks.
385                  */
386                 if (!host->h_server)
387                         args.flags |= RPC_CLNT_CREATE_HARDRTRY;
388                 if (host->h_noresvport)
389                         args.flags |= RPC_CLNT_CREATE_NONPRIVPORT;
390
391                 clnt = rpc_create(&args);
392                 if (!IS_ERR(clnt))
393                         host->h_rpcclnt = clnt;
394                 else {
395                         printk("lockd: couldn't create RPC handle for %s\n", host->h_name);
396                         clnt = NULL;
397                 }
398         }
399
400         mutex_unlock(&host->h_mutex);
401         return clnt;
402 }
403
404 /*
405  * Force a portmap lookup of the remote lockd port
406  */
407 void
408 nlm_rebind_host(struct nlm_host *host)
409 {
410         dprintk("lockd: rebind host %s\n", host->h_name);
411         if (host->h_rpcclnt && time_after_eq(jiffies, host->h_nextrebind)) {
412                 rpc_force_rebind(host->h_rpcclnt);
413                 host->h_nextrebind = jiffies + NLM_HOST_REBIND;
414         }
415 }
416
417 /*
418  * Increment NLM host count
419  */
420 struct nlm_host * nlm_get_host(struct nlm_host *host)
421 {
422         if (host) {
423                 dprintk("lockd: get host %s\n", host->h_name);
424                 atomic_inc(&host->h_count);
425                 host->h_expires = jiffies + NLM_HOST_EXPIRE;
426         }
427         return host;
428 }
429
430 /*
431  * Release NLM host after use
432  */
433 void nlm_release_host(struct nlm_host *host)
434 {
435         if (host != NULL) {
436                 dprintk("lockd: release host %s\n", host->h_name);
437                 BUG_ON(atomic_read(&host->h_count) < 0);
438                 if (atomic_dec_and_test(&host->h_count)) {
439                         BUG_ON(!list_empty(&host->h_lockowners));
440                         BUG_ON(!list_empty(&host->h_granted));
441                         BUG_ON(!list_empty(&host->h_reclaim));
442                 }
443         }
444 }
445
446 /**
447  * nlm_host_rebooted - Release all resources held by rebooted host
448  * @info: pointer to decoded results of NLM_SM_NOTIFY call
449  *
450  * We were notified that the specified host has rebooted.  Release
451  * all resources held by that peer.
452  */
453 void nlm_host_rebooted(const struct nlm_reboot *info)
454 {
455         struct hlist_head *chain;
456         struct hlist_node *pos;
457         struct nsm_handle *nsm;
458         struct nlm_host *host;
459
460         nsm = nsm_reboot_lookup(info);
461         if (unlikely(nsm == NULL))
462                 return;
463
464         /* Mark all hosts tied to this NSM state as having rebooted.
465          * We run the loop repeatedly, because we drop the host table
466          * lock for this.
467          * To avoid processing a host several times, we match the nsmstate.
468          */
469 again:  mutex_lock(&nlm_host_mutex);
470         for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
471                 hlist_for_each_entry(host, pos, chain, h_hash) {
472                         if (host->h_nsmhandle == nsm
473                          && host->h_nsmstate != info->state) {
474                                 host->h_nsmstate = info->state;
475                                 host->h_state++;
476
477                                 nlm_get_host(host);
478                                 mutex_unlock(&nlm_host_mutex);
479
480                                 if (host->h_server) {
481                                         /* We're server for this guy, just ditch
482                                          * all the locks he held. */
483                                         nlmsvc_free_host_resources(host);
484                                 } else {
485                                         /* He's the server, initiate lock recovery. */
486                                         nlmclnt_recovery(host);
487                                 }
488
489                                 nlm_release_host(host);
490                                 goto again;
491                         }
492                 }
493         }
494
495         mutex_unlock(&nlm_host_mutex);
496 }
497
498 /*
499  * Shut down the hosts module.
500  * Note that this routine is called only at server shutdown time.
501  */
502 void
503 nlm_shutdown_hosts(void)
504 {
505         struct hlist_head *chain;
506         struct hlist_node *pos;
507         struct nlm_host *host;
508
509         dprintk("lockd: shutting down host module\n");
510         mutex_lock(&nlm_host_mutex);
511
512         /* First, make all hosts eligible for gc */
513         dprintk("lockd: nuking all hosts...\n");
514         for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
515                 hlist_for_each_entry(host, pos, chain, h_hash) {
516                         host->h_expires = jiffies - 1;
517                         if (host->h_rpcclnt) {
518                                 rpc_shutdown_client(host->h_rpcclnt);
519                                 host->h_rpcclnt = NULL;
520                         }
521                 }
522         }
523
524         /* Then, perform a garbage collection pass */
525         nlm_gc_hosts();
526         mutex_unlock(&nlm_host_mutex);
527
528         /* complain if any hosts are left */
529         if (nrhosts) {
530                 printk(KERN_WARNING "lockd: couldn't shutdown host module!\n");
531                 dprintk("lockd: %d hosts left:\n", nrhosts);
532                 for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
533                         hlist_for_each_entry(host, pos, chain, h_hash) {
534                                 dprintk("       %s (cnt %d use %d exp %ld)\n",
535                                         host->h_name, atomic_read(&host->h_count),
536                                         host->h_inuse, host->h_expires);
537                         }
538                 }
539         }
540 }
541
542 /*
543  * Garbage collect any unused NLM hosts.
544  * This GC combines reference counting for async operations with
545  * mark & sweep for resources held by remote clients.
546  */
547 static void
548 nlm_gc_hosts(void)
549 {
550         struct hlist_head *chain;
551         struct hlist_node *pos, *next;
552         struct nlm_host *host;
553
554         dprintk("lockd: host garbage collection\n");
555         for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
556                 hlist_for_each_entry(host, pos, chain, h_hash)
557                         host->h_inuse = 0;
558         }
559
560         /* Mark all hosts that hold locks, blocks or shares */
561         nlmsvc_mark_resources();
562
563         for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
564                 hlist_for_each_entry_safe(host, pos, next, chain, h_hash) {
565                         if (atomic_read(&host->h_count) || host->h_inuse
566                          || time_before(jiffies, host->h_expires)) {
567                                 dprintk("nlm_gc_hosts skipping %s (cnt %d use %d exp %ld)\n",
568                                         host->h_name, atomic_read(&host->h_count),
569                                         host->h_inuse, host->h_expires);
570                                 continue;
571                         }
572                         dprintk("lockd: delete host %s\n", host->h_name);
573                         hlist_del_init(&host->h_hash);
574
575                         nlm_destroy_host(host);
576                         nrhosts--;
577                 }
578         }
579
580         next_gc = jiffies + NLM_HOST_COLLECT;
581 }