1 /*
2 * linux/fs/nfsd/nfssvc.c
3 *
4 * Central processing for nfsd.
5 *
6 * Authors: Olaf Kirch (okir@monad.swb.de)
7 *
8 * Copyright (C) 1995, 1996, 1997 Olaf Kirch <okir@monad.swb.de>
9 */
10
11 #include <linux/config.h>
12 #include <linux/module.h>
13
14 #include <linux/time.h>
15 #include <linux/errno.h>
16 #include <linux/nfs.h>
17 #include <linux/in.h>
18 #include <linux/uio.h>
19 #include <linux/unistd.h>
20 #include <linux/slab.h>
21 #include <linux/smp.h>
22 #include <linux/smp_lock.h>
23 #include <linux/fs_struct.h>
24
25 #include <linux/sunrpc/types.h>
26 #include <linux/sunrpc/stats.h>
27 #include <linux/sunrpc/svc.h>
28 #include <linux/sunrpc/svcsock.h>
29 #include <linux/sunrpc/cache.h>
30 #include <linux/nfsd/nfsd.h>
31 #include <linux/nfsd/stats.h>
32 #include <linux/nfsd/cache.h>
33 #include <linux/lockd/bind.h>
34
35 #define NFSDDBG_FACILITY NFSDDBG_SVC
36
37 /* these signals will be delivered to an nfsd thread
38 * when handling a request
39 */
40 #define ALLOWED_SIGS (sigmask(SIGKILL))
41 /* these signals will be delivered to an nfsd thread
42 * when not handling a request. i.e. when waiting
43 */
44 #define SHUTDOWN_SIGS (sigmask(SIGKILL) | sigmask(SIGHUP) | sigmask(SIGINT) | sigmask(SIGQUIT))
45 /* if the last thread dies with SIGHUP, then the exports table is
46 * left unchanged ( like 2.4-{0-9} ). Any other signal will clear
47 * the exports table (like 2.2).
48 */
49 #define SIG_NOCLEAN SIGHUP
50
51 extern struct svc_program nfsd_program;
52 static void nfsd(struct svc_rqst *rqstp);
53 struct timeval nfssvc_boot;
54 static struct svc_serv *nfsd_serv;
55 static atomic_t nfsd_busy;
56 static unsigned long nfsd_last_call;
57 static DEFINE_SPINLOCK(nfsd_call_lock);
58
59 struct nfsd_list {
60 struct list_head list;
61 struct task_struct *task;
62 };
63 struct list_head nfsd_list = LIST_HEAD_INIT(nfsd_list);
64
65 /*
66 * Maximum number of nfsd processes
67 */
68 #define NFSD_MAXSERVS 8192
69
70 int nfsd_nrthreads(void)
71 {
72 if (nfsd_serv == NULL)
73 return 0;
74 else
75 return nfsd_serv->sv_nrthreads;
76 }
77
78 int
79 nfsd_svc(unsigned short port, int nrservs)
80 {
81 int error;
82 int none_left;
83 struct list_head *victim;
84
85 lock_kernel();
86 dprintk("nfsd: creating service\n");
87 error = -EINVAL;
88 if (nrservs <= 0)
89 nrservs = 0;
90 if (nrservs > NFSD_MAXSERVS)
91 nrservs = NFSD_MAXSERVS;
92
93 /* Readahead param cache - will no-op if it already exists */
94 error = nfsd_racache_init(2*nrservs);
95 nfs4_state_init();
96 if (error<0)
97 goto out;
98 if (!nfsd_serv) {
99 atomic_set(&nfsd_busy, 0);
100 error = -ENOMEM;
101 nfsd_serv = svc_create(&nfsd_program, NFSD_BUFSIZE);
102 if (nfsd_serv == NULL)
103 goto out;
104 error = svc_makesock(nfsd_serv, IPPROTO_UDP, port);
105 if (error < 0)
106 goto failure;
107
108 #ifdef CONFIG_NFSD_TCP
109 error = svc_makesock(nfsd_serv, IPPROTO_TCP, port);
110 if (error < 0)
111 goto failure;
112 #endif
113 do_gettimeofday(&nfssvc_boot); /* record boot time */
114 } else
115 nfsd_serv->sv_nrthreads++;
116 nrservs -= (nfsd_serv->sv_nrthreads-1);
117 while (nrservs > 0) {
118 nrservs--;
119 __module_get(THIS_MODULE);
120 error = svc_create_thread(nfsd, nfsd_serv);
121 if (error < 0) {
122 module_put(THIS_MODULE);
123 break;
124 }
125 }
126 victim = nfsd_list.next;
127 while (nrservs < 0 && victim != &nfsd_list) {
128 struct nfsd_list *nl =
129 list_entry(victim,struct nfsd_list, list);
130 victim = victim->next;
131 send_sig(SIG_NOCLEAN, nl->task, 1);
132 nrservs++;
133 }
134 failure:
135 none_left = (nfsd_serv->sv_nrthreads == 1);
136 svc_destroy(nfsd_serv); /* Release server */
137 if (none_left) {
138 nfsd_serv = NULL;
139 nfsd_racache_shutdown();
140 nfs4_state_shutdown();
141 }
142 out:
143 unlock_kernel();
144 return error;
145 }
146
147 static inline void
148 update_thread_usage(int busy_threads)
149 {
150 unsigned long prev_call;
151 unsigned long diff;
152 int decile;
153
154 spin_lock(&nfsd_call_lock);
155 prev_call = nfsd_last_call;
156 nfsd_last_call = jiffies;
157 decile = busy_threads*10/nfsdstats.th_cnt;
158 if (decile>0 && decile <= 10) {
159 diff = nfsd_last_call - prev_call;
160 if ( (nfsdstats.th_usage[decile-1] += diff) >= NFSD_USAGE_WRAP)
161 nfsdstats.th_usage[decile-1] -= NFSD_USAGE_WRAP;
162 if (decile == 10)
163 nfsdstats.th_fullcnt++;
164 }
165 spin_unlock(&nfsd_call_lock);
166 }
167
168 /*
169 * This is the NFS server kernel thread
170 */
171 static void
172 nfsd(struct svc_rqst *rqstp)
173 {
174 struct svc_serv *serv = rqstp->rq_server;
175 struct fs_struct *fsp;
176 int err;
177 struct nfsd_list me;
178 sigset_t shutdown_mask, allowed_mask;
179
180 /* Lock module and set up kernel thread */
181 lock_kernel();
182 daemonize("nfsd");
183
184 /* After daemonize() this kernel thread shares current->fs
185 * with the init process. We need to create files with a
186 * umask of 0 instead of init's umask. */
187 fsp = copy_fs_struct(current->fs);
188 if (!fsp) {
189 printk("Unable to start nfsd thread: out of memory\n");
190 goto out;
191 }
192 exit_fs(current);
193 current->fs = fsp;
194 current->fs->umask = 0;
195
196 siginitsetinv(&shutdown_mask, SHUTDOWN_SIGS);
197 siginitsetinv(&allowed_mask, ALLOWED_SIGS);
198
199 nfsdstats.th_cnt++;
200
201 lockd_up(); /* start lockd */
202
203 me.task = current;
204 list_add(&me.list, &nfsd_list);
205
206 unlock_kernel();
207
208 /*
209 * We want less throttling in balance_dirty_pages() so that nfs to
210 * localhost doesn't cause nfsd to lock up due to all the client's
211 * dirty pages.
212 */
213 current->flags |= PF_LESS_THROTTLE;
214
215 /*
216 * The main request loop
217 */
218 for (;;) {
219 /* Block all but the shutdown signals */
220 sigprocmask(SIG_SETMASK, &shutdown_mask, NULL);
221
222 /*
223 * Find a socket with data available and call its
224 * recvfrom routine.
225 */
226 while ((err = svc_recv(serv, rqstp,
227 60*60*HZ)) == -EAGAIN)
228 ;
229 if (err < 0)
230 break;
231 update_thread_usage(atomic_read(&nfsd_busy));
232 atomic_inc(&nfsd_busy);
233
234 /* Lock the export hash tables for reading. */
235 exp_readlock();
236
237 /* Process request with signals blocked. */
238 sigprocmask(SIG_SETMASK, &allowed_mask, NULL);
239
240 svc_process(serv, rqstp);
241
242 /* Unlock export hash tables */
243 exp_readunlock();
244 update_thread_usage(atomic_read(&nfsd_busy));
245 atomic_dec(&nfsd_busy);
246 }
247
248 if (err != -EINTR) {
249 printk(KERN_WARNING "nfsd: terminating on error %d\n", -err);
250 } else {
251 unsigned int signo;
252
253 for (signo = 1; signo <= _NSIG; signo++)
254 if (sigismember(¤t->pending.signal, signo) &&
255 !sigismember(¤t->blocked, signo))
256 break;
257 err = signo;
258 }
259
260 lock_kernel();
261
262 /* Release lockd */
263 lockd_down();
264
265 /* Check if this is last thread */
266 if (serv->sv_nrthreads==1) {
267
268 printk(KERN_WARNING "nfsd: last server has exited\n");
269 if (err != SIG_NOCLEAN) {
270 printk(KERN_WARNING "nfsd: unexporting all filesystems\n");
271 nfsd_export_flush();
272 }
273 nfsd_serv = NULL;
274 nfsd_racache_shutdown(); /* release read-ahead cache */
275 nfs4_state_shutdown();
276 }
277 list_del(&me.list);
278 nfsdstats.th_cnt --;
279
280 out:
281 /* Release the thread */
282 svc_exit_thread(rqstp);
283
284 /* Release module */
285 module_put_and_exit(0);
286 }
287
288 int
289 nfsd_dispatch(struct svc_rqst *rqstp, u32 *statp)
290 {
291 struct svc_procedure *proc;
292 kxdrproc_t xdr;
293 u32 nfserr;
294 u32 *nfserrp;
295
296 dprintk("nfsd_dispatch: vers %d proc %d\n",
297 rqstp->rq_vers, rqstp->rq_proc);
298 proc = rqstp->rq_procinfo;
299
300 /* Check whether we have this call in the cache. */
301 switch (nfsd_cache_lookup(rqstp, proc->pc_cachetype)) {
302 case RC_INTR:
303 case RC_DROPIT:
304 return 0;
305 case RC_REPLY:
306 return 1;
307 case RC_DOIT:;
308 /* do it */
309 }
310
311 /* Decode arguments */
312 xdr = proc->pc_decode;
313 if (xdr && !xdr(rqstp, (u32*)rqstp->rq_arg.head[0].iov_base,
314 rqstp->rq_argp)) {
315 dprintk("nfsd: failed to decode arguments!\n");
316 nfsd_cache_update(rqstp, RC_NOCACHE, NULL);
317 *statp = rpc_garbage_args;
318 return 1;
319 }
320
321 /* need to grab the location to store the status, as
322 * nfsv4 does some encoding while processing
323 */
324 nfserrp = rqstp->rq_res.head[0].iov_base
325 + rqstp->rq_res.head[0].iov_len;
326 rqstp->rq_res.head[0].iov_len += sizeof(u32);
327
328 /* Now call the procedure handler, and encode NFS status. */
329 nfserr = proc->pc_func(rqstp, rqstp->rq_argp, rqstp->rq_resp);
330 if (nfserr == nfserr_jukebox && rqstp->rq_vers == 2)
331 nfserr = nfserr_dropit;
332 if (nfserr == nfserr_dropit) {
333 dprintk("nfsd: Dropping request due to malloc failure!\n");
334 nfsd_cache_update(rqstp, RC_NOCACHE, NULL);
335 return 0;
336 }
337
338 if (rqstp->rq_proc != 0)
339 *nfserrp++ = nfserr;
340
341 /* Encode result.
342 * For NFSv2, additional info is never returned in case of an error.
343 */
344 if (!(nfserr && rqstp->rq_vers == 2)) {
345 xdr = proc->pc_encode;
346 if (xdr && !xdr(rqstp, nfserrp,
347 rqstp->rq_resp)) {
348 /* Failed to encode result. Release cache entry */
349 dprintk("nfsd: failed to encode result!\n");
350 nfsd_cache_update(rqstp, RC_NOCACHE, NULL);
351 *statp = rpc_system_err;
352 return 1;
353 }
354 }
355
356 /* Store reply in cache. */
357 nfsd_cache_update(rqstp, proc->pc_cachetype, statp + 1);
358 return 1;
359 }
360
361 extern struct svc_version nfsd_version2, nfsd_version3, nfsd_version4;
362
363 static struct svc_version * nfsd_version[] = {
364 [2] = &nfsd_version2,
365 #if defined(CONFIG_NFSD_V3)
366 [3] = &nfsd_version3,
367 #endif
368 #if defined(CONFIG_NFSD_V4)
369 [4] = &nfsd_version4,
370 #endif
371 };
372
373 #define NFSD_NRVERS (sizeof(nfsd_version)/sizeof(nfsd_version[0]))
374 struct svc_program nfsd_program = {
375 .pg_prog = NFS_PROGRAM, /* program number */
376 .pg_nvers = NFSD_NRVERS, /* nr of entries in nfsd_version */
377 .pg_vers = nfsd_version, /* version table */
378 .pg_name = "nfsd", /* program name */
379 .pg_class = "nfsd", /* authentication class */
380 .pg_stats = &nfsd_svcstats, /* version table */
381 };
382
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