bcc21b05808a76d9b14ca90bb54bfab6228ecdf6
[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/sched.h>
13 #include <linux/slab.h>
14 #include <linux/in.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
22 #define NLMDBG_FACILITY         NLMDBG_HOSTCACHE
23 #define NLM_HOST_MAX            64
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         ((nrhosts > NLM_HOST_MAX)? 300 * HZ : 120 * HZ)
28 #define NLM_HOST_COLLECT        ((nrhosts > NLM_HOST_MAX)? 120 * HZ :  60 * HZ)
29
30 static struct nlm_host *        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
38 /*
39  * Find an NLM server handle in the cache. If there is none, create it.
40  */
41 struct nlm_host *
42 nlmclnt_lookup_host(const struct sockaddr_in *sin, int proto, int version)
43 {
44         return nlm_lookup_host(0, sin, proto, version);
45 }
46
47 /*
48  * Find an NLM client handle in the cache. If there is none, create it.
49  */
50 struct nlm_host *
51 nlmsvc_lookup_host(struct svc_rqst *rqstp)
52 {
53         return nlm_lookup_host(1, &rqstp->rq_addr,
54                                rqstp->rq_prot, rqstp->rq_vers);
55 }
56
57 /*
58  * Common host lookup routine for server & client
59  */
60 struct nlm_host *
61 nlm_lookup_host(int server, const struct sockaddr_in *sin,
62                                         int proto, int version)
63 {
64         struct nlm_host *host, **hp;
65         u32             addr;
66         int             hash;
67
68         dprintk("lockd: nlm_lookup_host(%08x, p=%d, v=%d)\n",
69                         (unsigned)(sin? ntohl(sin->sin_addr.s_addr) : 0), proto, version);
70
71         hash = NLM_ADDRHASH(sin->sin_addr.s_addr);
72
73         /* Lock hash table */
74         mutex_lock(&nlm_host_mutex);
75
76         if (time_after_eq(jiffies, next_gc))
77                 nlm_gc_hosts();
78
79         for (hp = &nlm_hosts[hash]; (host = *hp) != 0; hp = &host->h_next) {
80                 if (host->h_proto != proto)
81                         continue;
82                 if (host->h_version != version)
83                         continue;
84                 if (host->h_server != server)
85                         continue;
86
87                 if (nlm_cmp_addr(&host->h_addr, sin)) {
88                         if (hp != nlm_hosts + hash) {
89                                 *hp = host->h_next;
90                                 host->h_next = nlm_hosts[hash];
91                                 nlm_hosts[hash] = host;
92                         }
93                         nlm_get_host(host);
94                         mutex_unlock(&nlm_host_mutex);
95                         return host;
96                 }
97         }
98
99         /* Ooops, no host found, create it */
100         dprintk("lockd: creating host entry\n");
101
102         host = kzalloc(sizeof(*host), GFP_KERNEL);
103         if (!host)
104                 goto nohost;
105
106         addr = sin->sin_addr.s_addr;
107         sprintf(host->h_name, "%u.%u.%u.%u", NIPQUAD(addr));
108
109         host->h_addr       = *sin;
110         host->h_addr.sin_port = 0;      /* ouch! */
111         host->h_version    = version;
112         host->h_proto      = proto;
113         host->h_rpcclnt    = NULL;
114         mutex_init(&host->h_mutex);
115         host->h_nextrebind = jiffies + NLM_HOST_REBIND;
116         host->h_expires    = jiffies + NLM_HOST_EXPIRE;
117         atomic_set(&host->h_count, 1);
118         init_waitqueue_head(&host->h_gracewait);
119         init_rwsem(&host->h_rwsem);
120         host->h_state      = 0;                 /* pseudo NSM state */
121         host->h_nsmstate   = 0;                 /* real NSM state */
122         host->h_server     = server;
123         host->h_next       = nlm_hosts[hash];
124         nlm_hosts[hash]    = host;
125         INIT_LIST_HEAD(&host->h_lockowners);
126         spin_lock_init(&host->h_lock);
127         INIT_LIST_HEAD(&host->h_granted);
128         INIT_LIST_HEAD(&host->h_reclaim);
129
130         if (++nrhosts > NLM_HOST_MAX)
131                 next_gc = 0;
132
133 nohost:
134         mutex_unlock(&nlm_host_mutex);
135         return host;
136 }
137
138 struct nlm_host *
139 nlm_find_client(void)
140 {
141         /* find a nlm_host for a client for which h_killed == 0.
142          * and return it
143          */
144         int hash;
145         mutex_lock(&nlm_host_mutex);
146         for (hash = 0 ; hash < NLM_HOST_NRHASH; hash++) {
147                 struct nlm_host *host, **hp;
148                 for (hp = &nlm_hosts[hash]; (host = *hp) != 0; hp = &host->h_next) {
149                         if (host->h_server &&
150                             host->h_killed == 0) {
151                                 nlm_get_host(host);
152                                 mutex_unlock(&nlm_host_mutex);
153                                 return host;
154                         }
155                 }
156         }
157         mutex_unlock(&nlm_host_mutex);
158         return NULL;
159 }
160
161                                 
162 /*
163  * Create the NLM RPC client for an NLM peer
164  */
165 struct rpc_clnt *
166 nlm_bind_host(struct nlm_host *host)
167 {
168         struct rpc_clnt *clnt;
169
170         dprintk("lockd: nlm_bind_host(%08x)\n",
171                         (unsigned)ntohl(host->h_addr.sin_addr.s_addr));
172
173         /* Lock host handle */
174         mutex_lock(&host->h_mutex);
175
176         /* If we've already created an RPC client, check whether
177          * RPC rebind is required
178          */
179         if ((clnt = host->h_rpcclnt) != NULL) {
180                 if (time_after_eq(jiffies, host->h_nextrebind)) {
181                         rpc_force_rebind(clnt);
182                         host->h_nextrebind = jiffies + NLM_HOST_REBIND;
183                         dprintk("lockd: next rebind in %ld jiffies\n",
184                                         host->h_nextrebind - jiffies);
185                 }
186         } else {
187                 unsigned long increment = nlmsvc_timeout * HZ;
188                 struct rpc_timeout timeparms = {
189                         .to_initval     = increment,
190                         .to_increment   = increment,
191                         .to_maxval      = increment * 6UL,
192                         .to_retries     = 5U,
193                 };
194                 struct rpc_create_args args = {
195                         .protocol       = host->h_proto,
196                         .address        = (struct sockaddr *)&host->h_addr,
197                         .addrsize       = sizeof(host->h_addr),
198                         .timeout        = &timeparms,
199                         .servername     = host->h_name,
200                         .program        = &nlm_program,
201                         .version        = host->h_version,
202                         .authflavor     = RPC_AUTH_UNIX,
203                         .flags          = (RPC_CLNT_CREATE_HARDRTRY |
204                                            RPC_CLNT_CREATE_AUTOBIND),
205                 };
206
207                 clnt = rpc_create(&args);
208                 if (!IS_ERR(clnt))
209                         host->h_rpcclnt = clnt;
210                 else {
211                         printk("lockd: couldn't create RPC handle for %s\n", host->h_name);
212                         clnt = NULL;
213                 }
214         }
215
216         mutex_unlock(&host->h_mutex);
217         return clnt;
218 }
219
220 /*
221  * Force a portmap lookup of the remote lockd port
222  */
223 void
224 nlm_rebind_host(struct nlm_host *host)
225 {
226         dprintk("lockd: rebind host %s\n", host->h_name);
227         if (host->h_rpcclnt && time_after_eq(jiffies, host->h_nextrebind)) {
228                 rpc_force_rebind(host->h_rpcclnt);
229                 host->h_nextrebind = jiffies + NLM_HOST_REBIND;
230         }
231 }
232
233 /*
234  * Increment NLM host count
235  */
236 struct nlm_host * nlm_get_host(struct nlm_host *host)
237 {
238         if (host) {
239                 dprintk("lockd: get host %s\n", host->h_name);
240                 atomic_inc(&host->h_count);
241                 host->h_expires = jiffies + NLM_HOST_EXPIRE;
242         }
243         return host;
244 }
245
246 /*
247  * Release NLM host after use
248  */
249 void nlm_release_host(struct nlm_host *host)
250 {
251         if (host != NULL) {
252                 dprintk("lockd: release host %s\n", host->h_name);
253                 BUG_ON(atomic_read(&host->h_count) < 0);
254                 if (atomic_dec_and_test(&host->h_count)) {
255                         BUG_ON(!list_empty(&host->h_lockowners));
256                         BUG_ON(!list_empty(&host->h_granted));
257                         BUG_ON(!list_empty(&host->h_reclaim));
258                 }
259         }
260 }
261
262 /*
263  * We were notified that the host indicated by address &sin
264  * has rebooted.
265  * Release all resources held by that peer.
266  */
267 void nlm_host_rebooted(const struct sockaddr_in *sin, const struct nlm_reboot *argp)
268 {
269         struct nlm_host *host;
270
271         /* Obtain the host pointer for this NFS server and try to
272          * reclaim all locks we hold on this server.
273          */
274         if ((argp->proto & 1)==0) {
275                 /* We are client, he's the server: try to reclaim all locks. */
276                 if ((host = nlmclnt_lookup_host(sin, argp->proto >> 1, argp->vers)) == NULL)
277                         return;
278                 nlmclnt_recovery(host, argp->state);
279         } else {
280                 /* He's the client, we're the server: delete all locks held by the client */
281                 if ((host = nlm_lookup_host(1, sin, argp->proto >> 1, argp->vers)) == NULL)
282                         return;
283                 nlmsvc_free_host_resources(host);
284         }
285         nlm_release_host(host);
286 }
287
288 /*
289  * Shut down the hosts module.
290  * Note that this routine is called only at server shutdown time.
291  */
292 void
293 nlm_shutdown_hosts(void)
294 {
295         struct nlm_host *host;
296         int             i;
297
298         dprintk("lockd: shutting down host module\n");
299         mutex_lock(&nlm_host_mutex);
300
301         /* First, make all hosts eligible for gc */
302         dprintk("lockd: nuking all hosts...\n");
303         for (i = 0; i < NLM_HOST_NRHASH; i++) {
304                 for (host = nlm_hosts[i]; host; host = host->h_next)
305                         host->h_expires = jiffies - 1;
306         }
307
308         /* Then, perform a garbage collection pass */
309         nlm_gc_hosts();
310         mutex_unlock(&nlm_host_mutex);
311
312         /* complain if any hosts are left */
313         if (nrhosts) {
314                 printk(KERN_WARNING "lockd: couldn't shutdown host module!\n");
315                 dprintk("lockd: %d hosts left:\n", nrhosts);
316                 for (i = 0; i < NLM_HOST_NRHASH; i++) {
317                         for (host = nlm_hosts[i]; host; host = host->h_next) {
318                                 dprintk("       %s (cnt %d use %d exp %ld)\n",
319                                         host->h_name, atomic_read(&host->h_count),
320                                         host->h_inuse, host->h_expires);
321                         }
322                 }
323         }
324 }
325
326 /*
327  * Garbage collect any unused NLM hosts.
328  * This GC combines reference counting for async operations with
329  * mark & sweep for resources held by remote clients.
330  */
331 static void
332 nlm_gc_hosts(void)
333 {
334         struct nlm_host **q, *host;
335         struct rpc_clnt *clnt;
336         int             i;
337
338         dprintk("lockd: host garbage collection\n");
339         for (i = 0; i < NLM_HOST_NRHASH; i++) {
340                 for (host = nlm_hosts[i]; host; host = host->h_next)
341                         host->h_inuse = 0;
342         }
343
344         /* Mark all hosts that hold locks, blocks or shares */
345         nlmsvc_mark_resources();
346
347         for (i = 0; i < NLM_HOST_NRHASH; i++) {
348                 q = &nlm_hosts[i];
349                 while ((host = *q) != NULL) {
350                         if (atomic_read(&host->h_count) || host->h_inuse
351                          || time_before(jiffies, host->h_expires)) {
352                                 dprintk("nlm_gc_hosts skipping %s (cnt %d use %d exp %ld)\n",
353                                         host->h_name, atomic_read(&host->h_count),
354                                         host->h_inuse, host->h_expires);
355                                 q = &host->h_next;
356                                 continue;
357                         }
358                         dprintk("lockd: delete host %s\n", host->h_name);
359                         *q = host->h_next;
360
361                         /*
362                          * Unmonitor unless host was invalidated (i.e. lockd restarted)
363                          */
364                         nsm_unmonitor(host);
365
366                         if ((clnt = host->h_rpcclnt) != NULL) {
367                                 if (atomic_read(&clnt->cl_users)) {
368                                         printk(KERN_WARNING
369                                                 "lockd: active RPC handle\n");
370                                         clnt->cl_dead = 1;
371                                 } else {
372                                         rpc_destroy_client(host->h_rpcclnt);
373                                 }
374                         }
375                         kfree(host);
376                         nrhosts--;
377                 }
378         }
379
380         next_gc = jiffies + NLM_HOST_COLLECT;
381 }
382