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/module.h>
12 #include <linux/sched.h>
13 #include <linux/time.h>
14 #include <linux/errno.h>
15 #include <linux/nfs.h>
16 #include <linux/in.h>
17 #include <linux/uio.h>
18 #include <linux/unistd.h>
19 #include <linux/slab.h>
20 #include <linux/smp.h>
21 #include <linux/smp_lock.h>
22 #include <linux/freezer.h>
23 #include <linux/fs_struct.h>
24 #include <linux/kthread.h>
25
26 #include <linux/sunrpc/types.h>
27 #include <linux/sunrpc/stats.h>
28 #include <linux/sunrpc/svc.h>
29 #include <linux/sunrpc/svcsock.h>
30 #include <linux/sunrpc/cache.h>
31 #include <linux/nfsd/nfsd.h>
32 #include <linux/nfsd/stats.h>
33 #include <linux/nfsd/cache.h>
34 #include <linux/nfsd/syscall.h>
35 #include <linux/lockd/bind.h>
36 #include <linux/nfsacl.h>
37
38 #define NFSDDBG_FACILITY NFSDDBG_SVC
39
40 extern struct svc_program nfsd_program;
41 static int nfsd(void *vrqstp);
42 struct timeval nfssvc_boot;
43 static atomic_t nfsd_busy;
44 static unsigned long nfsd_last_call;
45 static DEFINE_SPINLOCK(nfsd_call_lock);
46
47 /*
48 * nfsd_mutex protects nfsd_serv -- both the pointer itself and the members
49 * of the svc_serv struct. In particular, ->sv_nrthreads but also to some
50 * extent ->sv_temp_socks and ->sv_permsocks. It also protects nfsdstats.th_cnt
51 *
52 * If (out side the lock) nfsd_serv is non-NULL, then it must point to a
53 * properly initialised 'struct svc_serv' with ->sv_nrthreads > 0. That number
54 * of nfsd threads must exist and each must listed in ->sp_all_threads in each
55 * entry of ->sv_pools[].
56 *
57 * Transitions of the thread count between zero and non-zero are of particular
58 * interest since the svc_serv needs to be created and initialized at that
59 * point, or freed.
60 *
61 * Finally, the nfsd_mutex also protects some of the global variables that are
62 * accessed when nfsd starts and that are settable via the write_* routines in
63 * nfsctl.c. In particular:
64 *
65 * user_recovery_dirname
66 * user_lease_time
67 * nfsd_versions
68 */
69 DEFINE_MUTEX(nfsd_mutex);
70 struct svc_serv *nfsd_serv;
71
72 #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
73 static struct svc_stat nfsd_acl_svcstats;
74 static struct svc_version * nfsd_acl_version[] = {
75 [2] = &nfsd_acl_version2,
76 [3] = &nfsd_acl_version3,
77 };
78
79 #define NFSD_ACL_MINVERS 2
80 #define NFSD_ACL_NRVERS ARRAY_SIZE(nfsd_acl_version)
81 static struct svc_version *nfsd_acl_versions[NFSD_ACL_NRVERS];
82
83 static struct svc_program nfsd_acl_program = {
84 .pg_prog = NFS_ACL_PROGRAM,
85 .pg_nvers = NFSD_ACL_NRVERS,
86 .pg_vers = nfsd_acl_versions,
87 .pg_name = "nfsacl",
88 .pg_class = "nfsd",
89 .pg_stats = &nfsd_acl_svcstats,
90 .pg_authenticate = &svc_set_client,
91 };
92
93 static struct svc_stat nfsd_acl_svcstats = {
94 .program = &nfsd_acl_program,
95 };
96 #endif /* defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL) */
97
98 static struct svc_version * nfsd_version[] = {
99 [2] = &nfsd_version2,
100 #if defined(CONFIG_NFSD_V3)
101 [3] = &nfsd_version3,
102 #endif
103 #if defined(CONFIG_NFSD_V4)
104 [4] = &nfsd_version4,
105 #endif
106 };
107
108 #define NFSD_MINVERS 2
109 #define NFSD_NRVERS ARRAY_SIZE(nfsd_version)
110 static struct svc_version *nfsd_versions[NFSD_NRVERS];
111
112 struct svc_program nfsd_program = {
113 #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
114 .pg_next = &nfsd_acl_program,
115 #endif
116 .pg_prog = NFS_PROGRAM, /* program number */
117 .pg_nvers = NFSD_NRVERS, /* nr of entries in nfsd_version */
118 .pg_vers = nfsd_versions, /* version table */
119 .pg_name = "nfsd", /* program name */
120 .pg_class = "nfsd", /* authentication class */
121 .pg_stats = &nfsd_svcstats, /* version table */
122 .pg_authenticate = &svc_set_client, /* export authentication */
123
124 };
125
nfsd_vers(int vers,enum vers_op change)126 int nfsd_vers(int vers, enum vers_op change)
127 {
128 if (vers < NFSD_MINVERS || vers >= NFSD_NRVERS)
129 return -1;
130 switch(change) {
131 case NFSD_SET:
132 nfsd_versions[vers] = nfsd_version[vers];
133 #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
134 if (vers < NFSD_ACL_NRVERS)
135 nfsd_acl_versions[vers] = nfsd_acl_version[vers];
136 #endif
137 break;
138 case NFSD_CLEAR:
139 nfsd_versions[vers] = NULL;
140 #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
141 if (vers < NFSD_ACL_NRVERS)
142 nfsd_acl_versions[vers] = NULL;
143 #endif
144 break;
145 case NFSD_TEST:
146 return nfsd_versions[vers] != NULL;
147 case NFSD_AVAIL:
148 return nfsd_version[vers] != NULL;
149 }
150 return 0;
151 }
152 /*
153 * Maximum number of nfsd processes
154 */
155 #define NFSD_MAXSERVS 8192
156
nfsd_nrthreads(void)157 int nfsd_nrthreads(void)
158 {
159 int rv = 0;
160 mutex_lock(&nfsd_mutex);
161 if (nfsd_serv)
162 rv = nfsd_serv->sv_nrthreads;
163 mutex_unlock(&nfsd_mutex);
164 return rv;
165 }
166
nfsd_last_thread(struct svc_serv * serv)167 static void nfsd_last_thread(struct svc_serv *serv)
168 {
169 /* When last nfsd thread exits we need to do some clean-up */
170 struct svc_xprt *xprt;
171 list_for_each_entry(xprt, &serv->sv_permsocks, xpt_list)
172 lockd_down();
173 nfsd_serv = NULL;
174 nfsd_racache_shutdown();
175 nfs4_state_shutdown();
176
177 printk(KERN_WARNING "nfsd: last server has exited, flushing export "
178 "cache\n");
179 nfsd_export_flush();
180 }
181
nfsd_reset_versions(void)182 void nfsd_reset_versions(void)
183 {
184 int found_one = 0;
185 int i;
186
187 for (i = NFSD_MINVERS; i < NFSD_NRVERS; i++) {
188 if (nfsd_program.pg_vers[i])
189 found_one = 1;
190 }
191
192 if (!found_one) {
193 for (i = NFSD_MINVERS; i < NFSD_NRVERS; i++)
194 nfsd_program.pg_vers[i] = nfsd_version[i];
195 #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
196 for (i = NFSD_ACL_MINVERS; i < NFSD_ACL_NRVERS; i++)
197 nfsd_acl_program.pg_vers[i] =
198 nfsd_acl_version[i];
199 #endif
200 }
201 }
202
203
nfsd_create_serv(void)204 int nfsd_create_serv(void)
205 {
206 int err = 0;
207
208 WARN_ON(!mutex_is_locked(&nfsd_mutex));
209 if (nfsd_serv) {
210 svc_get(nfsd_serv);
211 return 0;
212 }
213 if (nfsd_max_blksize == 0) {
214 /* choose a suitable default */
215 struct sysinfo i;
216 si_meminfo(&i);
217 /* Aim for 1/4096 of memory per thread
218 * This gives 1MB on 4Gig machines
219 * But only uses 32K on 128M machines.
220 * Bottom out at 8K on 32M and smaller.
221 * Of course, this is only a default.
222 */
223 nfsd_max_blksize = NFSSVC_MAXBLKSIZE;
224 i.totalram <<= PAGE_SHIFT - 12;
225 while (nfsd_max_blksize > i.totalram &&
226 nfsd_max_blksize >= 8*1024*2)
227 nfsd_max_blksize /= 2;
228 }
229
230 atomic_set(&nfsd_busy, 0);
231 nfsd_serv = svc_create_pooled(&nfsd_program, nfsd_max_blksize,
232 AF_INET,
233 nfsd_last_thread, nfsd, THIS_MODULE);
234 if (nfsd_serv == NULL)
235 err = -ENOMEM;
236
237 do_gettimeofday(&nfssvc_boot); /* record boot time */
238 return err;
239 }
240
nfsd_init_socks(int port)241 static int nfsd_init_socks(int port)
242 {
243 int error;
244 if (!list_empty(&nfsd_serv->sv_permsocks))
245 return 0;
246
247 error = svc_create_xprt(nfsd_serv, "udp", port,
248 SVC_SOCK_DEFAULTS);
249 if (error < 0)
250 return error;
251
252 error = lockd_up();
253 if (error < 0)
254 return error;
255
256 error = svc_create_xprt(nfsd_serv, "tcp", port,
257 SVC_SOCK_DEFAULTS);
258 if (error < 0)
259 return error;
260
261 error = lockd_up();
262 if (error < 0)
263 return error;
264
265 return 0;
266 }
267
nfsd_nrpools(void)268 int nfsd_nrpools(void)
269 {
270 if (nfsd_serv == NULL)
271 return 0;
272 else
273 return nfsd_serv->sv_nrpools;
274 }
275
nfsd_get_nrthreads(int n,int * nthreads)276 int nfsd_get_nrthreads(int n, int *nthreads)
277 {
278 int i = 0;
279
280 if (nfsd_serv != NULL) {
281 for (i = 0; i < nfsd_serv->sv_nrpools && i < n; i++)
282 nthreads[i] = nfsd_serv->sv_pools[i].sp_nrthreads;
283 }
284
285 return 0;
286 }
287
nfsd_set_nrthreads(int n,int * nthreads)288 int nfsd_set_nrthreads(int n, int *nthreads)
289 {
290 int i = 0;
291 int tot = 0;
292 int err = 0;
293
294 WARN_ON(!mutex_is_locked(&nfsd_mutex));
295
296 if (nfsd_serv == NULL || n <= 0)
297 return 0;
298
299 if (n > nfsd_serv->sv_nrpools)
300 n = nfsd_serv->sv_nrpools;
301
302 /* enforce a global maximum number of threads */
303 tot = 0;
304 for (i = 0; i < n; i++) {
305 if (nthreads[i] > NFSD_MAXSERVS)
306 nthreads[i] = NFSD_MAXSERVS;
307 tot += nthreads[i];
308 }
309 if (tot > NFSD_MAXSERVS) {
310 /* total too large: scale down requested numbers */
311 for (i = 0; i < n && tot > 0; i++) {
312 int new = nthreads[i] * NFSD_MAXSERVS / tot;
313 tot -= (nthreads[i] - new);
314 nthreads[i] = new;
315 }
316 for (i = 0; i < n && tot > 0; i++) {
317 nthreads[i]--;
318 tot--;
319 }
320 }
321
322 /*
323 * There must always be a thread in pool 0; the admin
324 * can't shut down NFS completely using pool_threads.
325 */
326 if (nthreads[0] == 0)
327 nthreads[0] = 1;
328
329 /* apply the new numbers */
330 svc_get(nfsd_serv);
331 for (i = 0; i < n; i++) {
332 err = svc_set_num_threads(nfsd_serv, &nfsd_serv->sv_pools[i],
333 nthreads[i]);
334 if (err)
335 break;
336 }
337 svc_destroy(nfsd_serv);
338
339 return err;
340 }
341
342 int
nfsd_svc(unsigned short port,int nrservs)343 nfsd_svc(unsigned short port, int nrservs)
344 {
345 int error;
346
347 mutex_lock(&nfsd_mutex);
348 dprintk("nfsd: creating service\n");
349 error = -EINVAL;
350 if (nrservs <= 0)
351 nrservs = 0;
352 if (nrservs > NFSD_MAXSERVS)
353 nrservs = NFSD_MAXSERVS;
354
355 /* Readahead param cache - will no-op if it already exists */
356 error = nfsd_racache_init(2*nrservs);
357 if (error<0)
358 goto out;
359 nfs4_state_start();
360
361 nfsd_reset_versions();
362
363 error = nfsd_create_serv();
364
365 if (error)
366 goto out;
367 error = nfsd_init_socks(port);
368 if (error)
369 goto failure;
370
371 error = svc_set_num_threads(nfsd_serv, NULL, nrservs);
372 failure:
373 svc_destroy(nfsd_serv); /* Release server */
374 out:
375 mutex_unlock(&nfsd_mutex);
376 return error;
377 }
378
379 static inline void
update_thread_usage(int busy_threads)380 update_thread_usage(int busy_threads)
381 {
382 unsigned long prev_call;
383 unsigned long diff;
384 int decile;
385
386 spin_lock(&nfsd_call_lock);
387 prev_call = nfsd_last_call;
388 nfsd_last_call = jiffies;
389 decile = busy_threads*10/nfsdstats.th_cnt;
390 if (decile>0 && decile <= 10) {
391 diff = nfsd_last_call - prev_call;
392 if ( (nfsdstats.th_usage[decile-1] += diff) >= NFSD_USAGE_WRAP)
393 nfsdstats.th_usage[decile-1] -= NFSD_USAGE_WRAP;
394 if (decile == 10)
395 nfsdstats.th_fullcnt++;
396 }
397 spin_unlock(&nfsd_call_lock);
398 }
399
400 /*
401 * This is the NFS server kernel thread
402 */
403 static int
nfsd(void * vrqstp)404 nfsd(void *vrqstp)
405 {
406 struct svc_rqst *rqstp = (struct svc_rqst *) vrqstp;
407 struct fs_struct *fsp;
408 int err, preverr = 0;
409
410 /* Lock module and set up kernel thread */
411 mutex_lock(&nfsd_mutex);
412
413 /* At this point, the thread shares current->fs
414 * with the init process. We need to create files with a
415 * umask of 0 instead of init's umask. */
416 fsp = copy_fs_struct(current->fs);
417 if (!fsp) {
418 printk("Unable to start nfsd thread: out of memory\n");
419 goto out;
420 }
421 exit_fs(current);
422 current->fs = fsp;
423 current->fs->umask = 0;
424
425 /*
426 * thread is spawned with all signals set to SIG_IGN, re-enable
427 * the ones that will bring down the thread
428 */
429 allow_signal(SIGKILL);
430 allow_signal(SIGHUP);
431 allow_signal(SIGINT);
432 allow_signal(SIGQUIT);
433
434 nfsdstats.th_cnt++;
435 mutex_unlock(&nfsd_mutex);
436
437 /*
438 * We want less throttling in balance_dirty_pages() so that nfs to
439 * localhost doesn't cause nfsd to lock up due to all the client's
440 * dirty pages.
441 */
442 current->flags |= PF_LESS_THROTTLE;
443 set_freezable();
444
445 /*
446 * The main request loop
447 */
448 for (;;) {
449 /*
450 * Find a socket with data available and call its
451 * recvfrom routine.
452 */
453 while ((err = svc_recv(rqstp, 60*60*HZ)) == -EAGAIN)
454 ;
455 if (err == -EINTR)
456 break;
457 else if (err < 0) {
458 if (err != preverr) {
459 printk(KERN_WARNING "%s: unexpected error "
460 "from svc_recv (%d)\n", __func__, -err);
461 preverr = err;
462 }
463 schedule_timeout_uninterruptible(HZ);
464 continue;
465 }
466
467 update_thread_usage(atomic_read(&nfsd_busy));
468 atomic_inc(&nfsd_busy);
469
470 /* Lock the export hash tables for reading. */
471 exp_readlock();
472
473 svc_process(rqstp);
474
475 /* Unlock export hash tables */
476 exp_readunlock();
477 update_thread_usage(atomic_read(&nfsd_busy));
478 atomic_dec(&nfsd_busy);
479 }
480
481 /* Clear signals before calling svc_exit_thread() */
482 flush_signals(current);
483
484 mutex_lock(&nfsd_mutex);
485 nfsdstats.th_cnt --;
486
487 out:
488 /* Release the thread */
489 svc_exit_thread(rqstp);
490
491 /* Release module */
492 mutex_unlock(&nfsd_mutex);
493 module_put_and_exit(0);
494 return 0;
495 }
496
map_new_errors(u32 vers,__be32 nfserr)497 static __be32 map_new_errors(u32 vers, __be32 nfserr)
498 {
499 if (nfserr == nfserr_jukebox && vers == 2)
500 return nfserr_dropit;
501 if (nfserr == nfserr_wrongsec && vers < 4)
502 return nfserr_acces;
503 return nfserr;
504 }
505
506 int
nfsd_dispatch(struct svc_rqst * rqstp,__be32 * statp)507 nfsd_dispatch(struct svc_rqst *rqstp, __be32 *statp)
508 {
509 struct svc_procedure *proc;
510 kxdrproc_t xdr;
511 __be32 nfserr;
512 __be32 *nfserrp;
513
514 dprintk("nfsd_dispatch: vers %d proc %d\n",
515 rqstp->rq_vers, rqstp->rq_proc);
516 proc = rqstp->rq_procinfo;
517
518 /* Check whether we have this call in the cache. */
519 switch (nfsd_cache_lookup(rqstp, proc->pc_cachetype)) {
520 case RC_INTR:
521 case RC_DROPIT:
522 return 0;
523 case RC_REPLY:
524 return 1;
525 case RC_DOIT:;
526 /* do it */
527 }
528
529 /* Decode arguments */
530 xdr = proc->pc_decode;
531 if (xdr && !xdr(rqstp, (__be32*)rqstp->rq_arg.head[0].iov_base,
532 rqstp->rq_argp)) {
533 dprintk("nfsd: failed to decode arguments!\n");
534 nfsd_cache_update(rqstp, RC_NOCACHE, NULL);
535 *statp = rpc_garbage_args;
536 return 1;
537 }
538
539 /* need to grab the location to store the status, as
540 * nfsv4 does some encoding while processing
541 */
542 nfserrp = rqstp->rq_res.head[0].iov_base
543 + rqstp->rq_res.head[0].iov_len;
544 rqstp->rq_res.head[0].iov_len += sizeof(__be32);
545
546 /* Now call the procedure handler, and encode NFS status. */
547 nfserr = proc->pc_func(rqstp, rqstp->rq_argp, rqstp->rq_resp);
548 nfserr = map_new_errors(rqstp->rq_vers, nfserr);
549 if (nfserr == nfserr_dropit) {
550 dprintk("nfsd: Dropping request; may be revisited later\n");
551 nfsd_cache_update(rqstp, RC_NOCACHE, NULL);
552 return 0;
553 }
554
555 if (rqstp->rq_proc != 0)
556 *nfserrp++ = nfserr;
557
558 /* Encode result.
559 * For NFSv2, additional info is never returned in case of an error.
560 */
561 if (!(nfserr && rqstp->rq_vers == 2)) {
562 xdr = proc->pc_encode;
563 if (xdr && !xdr(rqstp, nfserrp,
564 rqstp->rq_resp)) {
565 /* Failed to encode result. Release cache entry */
566 dprintk("nfsd: failed to encode result!\n");
567 nfsd_cache_update(rqstp, RC_NOCACHE, NULL);
568 *statp = rpc_system_err;
569 return 1;
570 }
571 }
572
573 /* Store reply in cache. */
574 nfsd_cache_update(rqstp, proc->pc_cachetype, statp + 1);
575 return 1;
576 }
577