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