112ebf8b8dfe040c518e28f83b60fb7ff20fbd22
[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
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 #define NLM_HOST_ADDR(sv)       (&(sv)->s_nlmclnt->cl_xprt->addr)
29
30 static struct nlm_host *        nlm_hosts[NLM_HOST_NRHASH];
31 static unsigned long            next_gc;
32 static int                      nrhosts;
33 static DECLARE_MUTEX(nlm_host_sema);
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(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, 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         down(&nlm_host_sema);
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                         up(&nlm_host_sema);
95                         return host;
96                 }
97         }
98
99         /* Ooops, no host found, create it */
100         dprintk("lockd: creating host entry\n");
101
102         if (!(host = (struct nlm_host *) kmalloc(sizeof(*host), GFP_KERNEL)))
103                 goto nohost;
104         memset(host, 0, sizeof(*host));
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         init_MUTEX(&host->h_sema);
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         host->h_state      = 0;                 /* pseudo NSM state */
120         host->h_nsmstate   = 0;                 /* real NSM state */
121         host->h_server     = server;
122         host->h_next       = nlm_hosts[hash];
123         nlm_hosts[hash]    = host;
124         INIT_LIST_HEAD(&host->h_lockowners);
125         spin_lock_init(&host->h_lock);
126         INIT_LIST_HEAD(&host->h_granted);
127         INIT_LIST_HEAD(&host->h_reclaim);
128
129         if (++nrhosts > NLM_HOST_MAX)
130                 next_gc = 0;
131
132 nohost:
133         up(&nlm_host_sema);
134         return host;
135 }
136
137 struct nlm_host *
138 nlm_find_client(void)
139 {
140         /* find a nlm_host for a client for which h_killed == 0.
141          * and return it
142          */
143         int hash;
144         down(&nlm_host_sema);
145         for (hash = 0 ; hash < NLM_HOST_NRHASH; hash++) {
146                 struct nlm_host *host, **hp;
147                 for (hp = &nlm_hosts[hash]; (host = *hp) != 0; hp = &host->h_next) {
148                         if (host->h_server &&
149                             host->h_killed == 0) {
150                                 nlm_get_host(host);
151                                 up(&nlm_host_sema);
152                                 return host;
153                         }
154                 }
155         }
156         up(&nlm_host_sema);
157         return NULL;
158 }
159
160                                 
161 /*
162  * Create the NLM RPC client for an NLM peer
163  */
164 struct rpc_clnt *
165 nlm_bind_host(struct nlm_host *host)
166 {
167         struct rpc_clnt *clnt;
168         struct rpc_xprt *xprt;
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         down(&host->h_sema);
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                 xprt = clnt->cl_xprt;
181                 if (time_after_eq(jiffies, host->h_nextrebind)) {
182                         rpc_force_rebind(clnt);
183                         host->h_nextrebind = jiffies + NLM_HOST_REBIND;
184                         dprintk("lockd: next rebind in %ld jiffies\n",
185                                         host->h_nextrebind - jiffies);
186                 }
187         } else {
188                 xprt = xprt_create_proto(host->h_proto, &host->h_addr, NULL);
189                 if (IS_ERR(xprt))
190                         goto forgetit;
191
192                 xprt_set_timeout(&xprt->timeout, 5, nlmsvc_timeout);
193                 xprt->resvport = 1;     /* NLM requires a reserved port */
194
195                 /* Existing NLM servers accept AUTH_UNIX only */
196                 clnt = rpc_new_client(xprt, host->h_name, &nlm_program,
197                                         host->h_version, RPC_AUTH_UNIX);
198                 if (IS_ERR(clnt))
199                         goto forgetit;
200                 clnt->cl_autobind = 1;  /* turn on pmap queries */
201                 clnt->cl_softrtry = 1; /* All queries are soft */
202
203                 host->h_rpcclnt = clnt;
204         }
205
206         up(&host->h_sema);
207         return clnt;
208
209 forgetit:
210         printk("lockd: couldn't create RPC handle for %s\n", host->h_name);
211         up(&host->h_sema);
212         return NULL;
213 }
214
215 /*
216  * Force a portmap lookup of the remote lockd port
217  */
218 void
219 nlm_rebind_host(struct nlm_host *host)
220 {
221         dprintk("lockd: rebind host %s\n", host->h_name);
222         if (host->h_rpcclnt && time_after_eq(jiffies, host->h_nextrebind)) {
223                 rpc_force_rebind(host->h_rpcclnt);
224                 host->h_nextrebind = jiffies + NLM_HOST_REBIND;
225         }
226 }
227
228 /*
229  * Increment NLM host count
230  */
231 struct nlm_host * nlm_get_host(struct nlm_host *host)
232 {
233         if (host) {
234                 dprintk("lockd: get host %s\n", host->h_name);
235                 atomic_inc(&host->h_count);
236                 host->h_expires = jiffies + NLM_HOST_EXPIRE;
237         }
238         return host;
239 }
240
241 /*
242  * Release NLM host after use
243  */
244 void nlm_release_host(struct nlm_host *host)
245 {
246         if (host != NULL) {
247                 dprintk("lockd: release host %s\n", host->h_name);
248                 BUG_ON(atomic_read(&host->h_count) < 0);
249                 if (atomic_dec_and_test(&host->h_count)) {
250                         BUG_ON(!list_empty(&host->h_lockowners));
251                         BUG_ON(!list_empty(&host->h_granted));
252                         BUG_ON(!list_empty(&host->h_reclaim));
253                 }
254         }
255 }
256
257 /*
258  * Shut down the hosts module.
259  * Note that this routine is called only at server shutdown time.
260  */
261 void
262 nlm_shutdown_hosts(void)
263 {
264         struct nlm_host *host;
265         int             i;
266
267         dprintk("lockd: shutting down host module\n");
268         down(&nlm_host_sema);
269
270         /* First, make all hosts eligible for gc */
271         dprintk("lockd: nuking all hosts...\n");
272         for (i = 0; i < NLM_HOST_NRHASH; i++) {
273                 for (host = nlm_hosts[i]; host; host = host->h_next)
274                         host->h_expires = jiffies - 1;
275         }
276
277         /* Then, perform a garbage collection pass */
278         nlm_gc_hosts();
279         up(&nlm_host_sema);
280
281         /* complain if any hosts are left */
282         if (nrhosts) {
283                 printk(KERN_WARNING "lockd: couldn't shutdown host module!\n");
284                 dprintk("lockd: %d hosts left:\n", nrhosts);
285                 for (i = 0; i < NLM_HOST_NRHASH; i++) {
286                         for (host = nlm_hosts[i]; host; host = host->h_next) {
287                                 dprintk("       %s (cnt %d use %d exp %ld)\n",
288                                         host->h_name, atomic_read(&host->h_count),
289                                         host->h_inuse, host->h_expires);
290                         }
291                 }
292         }
293 }
294
295 /*
296  * Garbage collect any unused NLM hosts.
297  * This GC combines reference counting for async operations with
298  * mark & sweep for resources held by remote clients.
299  */
300 static void
301 nlm_gc_hosts(void)
302 {
303         struct nlm_host **q, *host;
304         struct rpc_clnt *clnt;
305         int             i;
306
307         dprintk("lockd: host garbage collection\n");
308         for (i = 0; i < NLM_HOST_NRHASH; i++) {
309                 for (host = nlm_hosts[i]; host; host = host->h_next)
310                         host->h_inuse = 0;
311         }
312
313         /* Mark all hosts that hold locks, blocks or shares */
314         nlmsvc_mark_resources();
315
316         for (i = 0; i < NLM_HOST_NRHASH; i++) {
317                 q = &nlm_hosts[i];
318                 while ((host = *q) != NULL) {
319                         if (atomic_read(&host->h_count) || host->h_inuse
320                          || time_before(jiffies, host->h_expires)) {
321                                 dprintk("nlm_gc_hosts skipping %s (cnt %d use %d exp %ld)\n",
322                                         host->h_name, atomic_read(&host->h_count),
323                                         host->h_inuse, host->h_expires);
324                                 q = &host->h_next;
325                                 continue;
326                         }
327                         dprintk("lockd: delete host %s\n", host->h_name);
328                         *q = host->h_next;
329                         /* Don't unmonitor hosts that have been invalidated */
330                         if (host->h_monitored && !host->h_killed)
331                                 nsm_unmonitor(host);
332                         if ((clnt = host->h_rpcclnt) != NULL) {
333                                 if (atomic_read(&clnt->cl_users)) {
334                                         printk(KERN_WARNING
335                                                 "lockd: active RPC handle\n");
336                                         clnt->cl_dead = 1;
337                                 } else {
338                                         rpc_destroy_client(host->h_rpcclnt);
339                                 }
340                         }
341                         kfree(host);
342                         nrhosts--;
343                 }
344         }
345
346         next_gc = jiffies + NLM_HOST_COLLECT;
347 }
348