Merge with rsync://rsync.kernel.org/pub/scm/linux/kernel/git/sfrench/cifs-2.6.git
[linux-2.6] / 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
127         if (++nrhosts > NLM_HOST_MAX)
128                 next_gc = 0;
129
130 nohost:
131         up(&nlm_host_sema);
132         return host;
133 }
134
135 struct nlm_host *
136 nlm_find_client(void)
137 {
138         /* find a nlm_host for a client for which h_killed == 0.
139          * and return it
140          */
141         int hash;
142         down(&nlm_host_sema);
143         for (hash = 0 ; hash < NLM_HOST_NRHASH; hash++) {
144                 struct nlm_host *host, **hp;
145                 for (hp = &nlm_hosts[hash]; (host = *hp) != 0; hp = &host->h_next) {
146                         if (host->h_server &&
147                             host->h_killed == 0) {
148                                 nlm_get_host(host);
149                                 up(&nlm_host_sema);
150                                 return host;
151                         }
152                 }
153         }
154         up(&nlm_host_sema);
155         return NULL;
156 }
157
158                                 
159 /*
160  * Create the NLM RPC client for an NLM peer
161  */
162 struct rpc_clnt *
163 nlm_bind_host(struct nlm_host *host)
164 {
165         struct rpc_clnt *clnt;
166         struct rpc_xprt *xprt;
167
168         dprintk("lockd: nlm_bind_host(%08x)\n",
169                         (unsigned)ntohl(host->h_addr.sin_addr.s_addr));
170
171         /* Lock host handle */
172         down(&host->h_sema);
173
174         /* If we've already created an RPC client, check whether
175          * RPC rebind is required
176          * Note: why keep rebinding if we're on a tcp connection?
177          */
178         if ((clnt = host->h_rpcclnt) != NULL) {
179                 xprt = clnt->cl_xprt;
180                 if (!xprt->stream && time_after_eq(jiffies, host->h_nextrebind)) {
181                         clnt->cl_port = 0;
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                 xprt = xprt_create_proto(host->h_proto, &host->h_addr, NULL);
188                 if (IS_ERR(xprt))
189                         goto forgetit;
190
191                 xprt_set_timeout(&xprt->timeout, 5, nlmsvc_timeout);
192                 xprt->nocong = 1;       /* No congestion control for NLM */
193                 xprt->resvport = 1;     /* NLM requires a reserved port */
194
195                 /* Existing NLM servers accept AUTH_UNIX only */
196                 clnt = rpc_create_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
202                 host->h_rpcclnt = clnt;
203         }
204
205         up(&host->h_sema);
206         return clnt;
207
208 forgetit:
209         printk("lockd: couldn't create RPC handle for %s\n", host->h_name);
210         up(&host->h_sema);
211         return NULL;
212 }
213
214 /*
215  * Force a portmap lookup of the remote lockd port
216  */
217 void
218 nlm_rebind_host(struct nlm_host *host)
219 {
220         dprintk("lockd: rebind host %s\n", host->h_name);
221         if (host->h_rpcclnt && time_after_eq(jiffies, host->h_nextrebind)) {
222                 host->h_rpcclnt->cl_port = 0;
223                 host->h_nextrebind = jiffies + NLM_HOST_REBIND;
224         }
225 }
226
227 /*
228  * Increment NLM host count
229  */
230 struct nlm_host * nlm_get_host(struct nlm_host *host)
231 {
232         if (host) {
233                 dprintk("lockd: get host %s\n", host->h_name);
234                 atomic_inc(&host->h_count);
235                 host->h_expires = jiffies + NLM_HOST_EXPIRE;
236         }
237         return host;
238 }
239
240 /*
241  * Release NLM host after use
242  */
243 void nlm_release_host(struct nlm_host *host)
244 {
245         if (host != NULL) {
246                 dprintk("lockd: release host %s\n", host->h_name);
247                 atomic_dec(&host->h_count);
248                 BUG_ON(atomic_read(&host->h_count) < 0);
249         }
250 }
251
252 /*
253  * Shut down the hosts module.
254  * Note that this routine is called only at server shutdown time.
255  */
256 void
257 nlm_shutdown_hosts(void)
258 {
259         struct nlm_host *host;
260         int             i;
261
262         dprintk("lockd: shutting down host module\n");
263         down(&nlm_host_sema);
264
265         /* First, make all hosts eligible for gc */
266         dprintk("lockd: nuking all hosts...\n");
267         for (i = 0; i < NLM_HOST_NRHASH; i++) {
268                 for (host = nlm_hosts[i]; host; host = host->h_next)
269                         host->h_expires = jiffies - 1;
270         }
271
272         /* Then, perform a garbage collection pass */
273         nlm_gc_hosts();
274         up(&nlm_host_sema);
275
276         /* complain if any hosts are left */
277         if (nrhosts) {
278                 printk(KERN_WARNING "lockd: couldn't shutdown host module!\n");
279                 dprintk("lockd: %d hosts left:\n", nrhosts);
280                 for (i = 0; i < NLM_HOST_NRHASH; i++) {
281                         for (host = nlm_hosts[i]; host; host = host->h_next) {
282                                 dprintk("       %s (cnt %d use %d exp %ld)\n",
283                                         host->h_name, atomic_read(&host->h_count),
284                                         host->h_inuse, host->h_expires);
285                         }
286                 }
287         }
288 }
289
290 /*
291  * Garbage collect any unused NLM hosts.
292  * This GC combines reference counting for async operations with
293  * mark & sweep for resources held by remote clients.
294  */
295 static void
296 nlm_gc_hosts(void)
297 {
298         struct nlm_host **q, *host;
299         struct rpc_clnt *clnt;
300         int             i;
301
302         dprintk("lockd: host garbage collection\n");
303         for (i = 0; i < NLM_HOST_NRHASH; i++) {
304                 for (host = nlm_hosts[i]; host; host = host->h_next)
305                         host->h_inuse = 0;
306         }
307
308         /* Mark all hosts that hold locks, blocks or shares */
309         nlmsvc_mark_resources();
310
311         for (i = 0; i < NLM_HOST_NRHASH; i++) {
312                 q = &nlm_hosts[i];
313                 while ((host = *q) != NULL) {
314                         if (atomic_read(&host->h_count) || host->h_inuse
315                          || time_before(jiffies, host->h_expires)) {
316                                 dprintk("nlm_gc_hosts skipping %s (cnt %d use %d exp %ld)\n",
317                                         host->h_name, atomic_read(&host->h_count),
318                                         host->h_inuse, host->h_expires);
319                                 q = &host->h_next;
320                                 continue;
321                         }
322                         dprintk("lockd: delete host %s\n", host->h_name);
323                         *q = host->h_next;
324                         /* Don't unmonitor hosts that have been invalidated */
325                         if (host->h_monitored && !host->h_killed)
326                                 nsm_unmonitor(host);
327                         if ((clnt = host->h_rpcclnt) != NULL) {
328                                 if (atomic_read(&clnt->cl_users)) {
329                                         printk(KERN_WARNING
330                                                 "lockd: active RPC handle\n");
331                                         clnt->cl_dead = 1;
332                                 } else {
333                                         rpc_destroy_client(host->h_rpcclnt);
334                                 }
335                         }
336                         BUG_ON(!list_empty(&host->h_lockowners));
337                         kfree(host);
338                         nrhosts--;
339                 }
340         }
341
342         next_gc = jiffies + NLM_HOST_COLLECT;
343 }
344