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 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/nfsd/syscall.h> 34 #include <linux/lockd/bind.h> 35 #include <linux/nfsacl.h> 36 37 #define NFSDDBG_FACILITY NFSDDBG_SVC 38 39 /* these signals will be delivered to an nfsd thread 40 * when handling a request 41 */ 42 #define ALLOWED_SIGS (sigmask(SIGKILL)) 43 /* these signals will be delivered to an nfsd thread 44 * when not handling a request. i.e. when waiting 45 */ 46 #define SHUTDOWN_SIGS (sigmask(SIGKILL) | sigmask(SIGHUP) | sigmask(SIGINT) | sigmask(SIGQUIT)) 47 /* if the last thread dies with SIGHUP, then the exports table is 48 * left unchanged ( like 2.4-{0-9} ). Any other signal will clear 49 * the exports table (like 2.2). 50 */ 51 #define SIG_NOCLEAN SIGHUP 52 53 extern struct svc_program nfsd_program; 54 static void nfsd(struct svc_rqst *rqstp); 55 struct timeval nfssvc_boot; 56 struct svc_serv *nfsd_serv; 57 static atomic_t nfsd_busy; 58 static unsigned long nfsd_last_call; 59 static DEFINE_SPINLOCK(nfsd_call_lock); 60 61 #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL) 62 static struct svc_stat nfsd_acl_svcstats; 63 static struct svc_version * nfsd_acl_version[] = { 64 [2] = &nfsd_acl_version2, 65 [3] = &nfsd_acl_version3, 66 }; 67 68 #define NFSD_ACL_MINVERS 2 69 #define NFSD_ACL_NRVERS ARRAY_SIZE(nfsd_acl_version) 70 static struct svc_version *nfsd_acl_versions[NFSD_ACL_NRVERS]; 71 72 static struct svc_program nfsd_acl_program = { 73 .pg_prog = NFS_ACL_PROGRAM, 74 .pg_nvers = NFSD_ACL_NRVERS, 75 .pg_vers = nfsd_acl_versions, 76 .pg_name = "nfsacl", 77 .pg_class = "nfsd", 78 .pg_stats = &nfsd_acl_svcstats, 79 .pg_authenticate = &svc_set_client, 80 }; 81 82 static struct svc_stat nfsd_acl_svcstats = { 83 .program = &nfsd_acl_program, 84 }; 85 #endif /* defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL) */ 86 87 static struct svc_version * nfsd_version[] = { 88 [2] = &nfsd_version2, 89 #if defined(CONFIG_NFSD_V3) 90 [3] = &nfsd_version3, 91 #endif 92 #if defined(CONFIG_NFSD_V4) 93 [4] = &nfsd_version4, 94 #endif 95 }; 96 97 #define NFSD_MINVERS 2 98 #define NFSD_NRVERS ARRAY_SIZE(nfsd_version) 99 static struct svc_version *nfsd_versions[NFSD_NRVERS]; 100 101 struct svc_program nfsd_program = { 102 #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL) 103 .pg_next = &nfsd_acl_program, 104 #endif 105 .pg_prog = NFS_PROGRAM, /* program number */ 106 .pg_nvers = NFSD_NRVERS, /* nr of entries in nfsd_version */ 107 .pg_vers = nfsd_versions, /* version table */ 108 .pg_name = "nfsd", /* program name */ 109 .pg_class = "nfsd", /* authentication class */ 110 .pg_stats = &nfsd_svcstats, /* version table */ 111 .pg_authenticate = &svc_set_client, /* export authentication */ 112 113 }; 114 115 int nfsd_vers(int vers, enum vers_op change) 116 { 117 if (vers < NFSD_MINVERS || vers >= NFSD_NRVERS) 118 return -1; 119 switch(change) { 120 case NFSD_SET: 121 nfsd_versions[vers] = nfsd_version[vers]; 122 #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL) 123 if (vers < NFSD_ACL_NRVERS) 124 nfsd_acl_versions[vers] = nfsd_acl_version[vers]; 125 #endif 126 break; 127 case NFSD_CLEAR: 128 nfsd_versions[vers] = NULL; 129 #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL) 130 if (vers < NFSD_ACL_NRVERS) 131 nfsd_acl_versions[vers] = NULL; 132 #endif 133 break; 134 case NFSD_TEST: 135 return nfsd_versions[vers] != NULL; 136 case NFSD_AVAIL: 137 return nfsd_version[vers] != NULL; 138 } 139 return 0; 140 } 141 /* 142 * Maximum number of nfsd processes 143 */ 144 #define NFSD_MAXSERVS 8192 145 146 int nfsd_nrthreads(void) 147 { 148 if (nfsd_serv == NULL) 149 return 0; 150 else 151 return nfsd_serv->sv_nrthreads; 152 } 153 154 static int killsig; /* signal that was used to kill last nfsd */ 155 static void nfsd_last_thread(struct svc_serv *serv) 156 { 157 /* When last nfsd thread exits we need to do some clean-up */ 158 struct svc_xprt *xprt; 159 list_for_each_entry(xprt, &serv->sv_permsocks, xpt_list) 160 lockd_down(); 161 nfsd_serv = NULL; 162 nfsd_racache_shutdown(); 163 nfs4_state_shutdown(); 164 165 printk(KERN_WARNING "nfsd: last server has exited\n"); 166 if (killsig != SIG_NOCLEAN) { 167 printk(KERN_WARNING "nfsd: unexporting all filesystems\n"); 168 nfsd_export_flush(); 169 } 170 } 171 172 void nfsd_reset_versions(void) 173 { 174 int found_one = 0; 175 int i; 176 177 for (i = NFSD_MINVERS; i < NFSD_NRVERS; i++) { 178 if (nfsd_program.pg_vers[i]) 179 found_one = 1; 180 } 181 182 if (!found_one) { 183 for (i = NFSD_MINVERS; i < NFSD_NRVERS; i++) 184 nfsd_program.pg_vers[i] = nfsd_version[i]; 185 #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL) 186 for (i = NFSD_ACL_MINVERS; i < NFSD_ACL_NRVERS; i++) 187 nfsd_acl_program.pg_vers[i] = 188 nfsd_acl_version[i]; 189 #endif 190 } 191 } 192 193 int nfsd_create_serv(void) 194 { 195 int err = 0; 196 lock_kernel(); 197 if (nfsd_serv) { 198 svc_get(nfsd_serv); 199 unlock_kernel(); 200 return 0; 201 } 202 if (nfsd_max_blksize == 0) { 203 /* choose a suitable default */ 204 struct sysinfo i; 205 si_meminfo(&i); 206 /* Aim for 1/4096 of memory per thread 207 * This gives 1MB on 4Gig machines 208 * But only uses 32K on 128M machines. 209 * Bottom out at 8K on 32M and smaller. 210 * Of course, this is only a default. 211 */ 212 nfsd_max_blksize = NFSSVC_MAXBLKSIZE; 213 i.totalram <<= PAGE_SHIFT - 12; 214 while (nfsd_max_blksize > i.totalram && 215 nfsd_max_blksize >= 8*1024*2) 216 nfsd_max_blksize /= 2; 217 } 218 219 atomic_set(&nfsd_busy, 0); 220 nfsd_serv = svc_create_pooled(&nfsd_program, 221 nfsd_max_blksize, 222 nfsd_last_thread, 223 nfsd, SIG_NOCLEAN, THIS_MODULE); 224 if (nfsd_serv == NULL) 225 err = -ENOMEM; 226 unlock_kernel(); 227 do_gettimeofday(&nfssvc_boot); /* record boot time */ 228 return err; 229 } 230 231 static int nfsd_init_socks(int port) 232 { 233 int error; 234 if (!list_empty(&nfsd_serv->sv_permsocks)) 235 return 0; 236 237 error = lockd_up(IPPROTO_UDP); 238 if (error >= 0) { 239 error = svc_create_xprt(nfsd_serv, "udp", port, 240 SVC_SOCK_DEFAULTS); 241 if (error < 0) 242 lockd_down(); 243 } 244 if (error < 0) 245 return error; 246 247 #ifdef CONFIG_NFSD_TCP 248 error = lockd_up(IPPROTO_TCP); 249 if (error >= 0) { 250 error = svc_create_xprt(nfsd_serv, "tcp", port, 251 SVC_SOCK_DEFAULTS); 252 if (error < 0) 253 lockd_down(); 254 } 255 if (error < 0) 256 return error; 257 #endif 258 return 0; 259 } 260 261 int nfsd_nrpools(void) 262 { 263 if (nfsd_serv == NULL) 264 return 0; 265 else 266 return nfsd_serv->sv_nrpools; 267 } 268 269 int nfsd_get_nrthreads(int n, int *nthreads) 270 { 271 int i = 0; 272 273 if (nfsd_serv != NULL) { 274 for (i = 0; i < nfsd_serv->sv_nrpools && i < n; i++) 275 nthreads[i] = nfsd_serv->sv_pools[i].sp_nrthreads; 276 } 277 278 return 0; 279 } 280 281 int nfsd_set_nrthreads(int n, int *nthreads) 282 { 283 int i = 0; 284 int tot = 0; 285 int err = 0; 286 287 if (nfsd_serv == NULL || n <= 0) 288 return 0; 289 290 if (n > nfsd_serv->sv_nrpools) 291 n = nfsd_serv->sv_nrpools; 292 293 /* enforce a global maximum number of threads */ 294 tot = 0; 295 for (i = 0; i < n; i++) { 296 if (nthreads[i] > NFSD_MAXSERVS) 297 nthreads[i] = NFSD_MAXSERVS; 298 tot += nthreads[i]; 299 } 300 if (tot > NFSD_MAXSERVS) { 301 /* total too large: scale down requested numbers */ 302 for (i = 0; i < n && tot > 0; i++) { 303 int new = nthreads[i] * NFSD_MAXSERVS / tot; 304 tot -= (nthreads[i] - new); 305 nthreads[i] = new; 306 } 307 for (i = 0; i < n && tot > 0; i++) { 308 nthreads[i]--; 309 tot--; 310 } 311 } 312 313 /* 314 * There must always be a thread in pool 0; the admin 315 * can't shut down NFS completely using pool_threads. 316 */ 317 if (nthreads[0] == 0) 318 nthreads[0] = 1; 319 320 /* apply the new numbers */ 321 lock_kernel(); 322 svc_get(nfsd_serv); 323 for (i = 0; i < n; i++) { 324 err = svc_set_num_threads(nfsd_serv, &nfsd_serv->sv_pools[i], 325 nthreads[i]); 326 if (err) 327 break; 328 } 329 svc_destroy(nfsd_serv); 330 unlock_kernel(); 331 332 return err; 333 } 334 335 int 336 nfsd_svc(unsigned short port, int nrservs) 337 { 338 int error; 339 340 lock_kernel(); 341 dprintk("nfsd: creating service\n"); 342 error = -EINVAL; 343 if (nrservs <= 0) 344 nrservs = 0; 345 if (nrservs > NFSD_MAXSERVS) 346 nrservs = NFSD_MAXSERVS; 347 348 /* Readahead param cache - will no-op if it already exists */ 349 error = nfsd_racache_init(2*nrservs); 350 if (error<0) 351 goto out; 352 nfs4_state_start(); 353 354 nfsd_reset_versions(); 355 356 error = nfsd_create_serv(); 357 358 if (error) 359 goto out; 360 error = nfsd_init_socks(port); 361 if (error) 362 goto failure; 363 364 error = svc_set_num_threads(nfsd_serv, NULL, nrservs); 365 failure: 366 svc_destroy(nfsd_serv); /* Release server */ 367 out: 368 unlock_kernel(); 369 return error; 370 } 371 372 static inline void 373 update_thread_usage(int busy_threads) 374 { 375 unsigned long prev_call; 376 unsigned long diff; 377 int decile; 378 379 spin_lock(&nfsd_call_lock); 380 prev_call = nfsd_last_call; 381 nfsd_last_call = jiffies; 382 decile = busy_threads*10/nfsdstats.th_cnt; 383 if (decile>0 && decile <= 10) { 384 diff = nfsd_last_call - prev_call; 385 if ( (nfsdstats.th_usage[decile-1] += diff) >= NFSD_USAGE_WRAP) 386 nfsdstats.th_usage[decile-1] -= NFSD_USAGE_WRAP; 387 if (decile == 10) 388 nfsdstats.th_fullcnt++; 389 } 390 spin_unlock(&nfsd_call_lock); 391 } 392 393 /* 394 * This is the NFS server kernel thread 395 */ 396 static void 397 nfsd(struct svc_rqst *rqstp) 398 { 399 struct fs_struct *fsp; 400 int err; 401 sigset_t shutdown_mask, allowed_mask; 402 403 /* Lock module and set up kernel thread */ 404 lock_kernel(); 405 daemonize("nfsd"); 406 407 /* After daemonize() this kernel thread shares current->fs 408 * with the init process. We need to create files with a 409 * umask of 0 instead of init's umask. */ 410 fsp = copy_fs_struct(current->fs); 411 if (!fsp) { 412 printk("Unable to start nfsd thread: out of memory\n"); 413 goto out; 414 } 415 exit_fs(current); 416 current->fs = fsp; 417 current->fs->umask = 0; 418 419 siginitsetinv(&shutdown_mask, SHUTDOWN_SIGS); 420 siginitsetinv(&allowed_mask, ALLOWED_SIGS); 421 422 nfsdstats.th_cnt++; 423 424 rqstp->rq_task = current; 425 426 unlock_kernel(); 427 428 /* 429 * We want less throttling in balance_dirty_pages() so that nfs to 430 * localhost doesn't cause nfsd to lock up due to all the client's 431 * dirty pages. 432 */ 433 current->flags |= PF_LESS_THROTTLE; 434 set_freezable(); 435 436 /* 437 * The main request loop 438 */ 439 for (;;) { 440 /* Block all but the shutdown signals */ 441 sigprocmask(SIG_SETMASK, &shutdown_mask, NULL); 442 443 /* 444 * Find a socket with data available and call its 445 * recvfrom routine. 446 */ 447 while ((err = svc_recv(rqstp, 60*60*HZ)) == -EAGAIN) 448 ; 449 if (err < 0) 450 break; 451 update_thread_usage(atomic_read(&nfsd_busy)); 452 atomic_inc(&nfsd_busy); 453 454 /* Lock the export hash tables for reading. */ 455 exp_readlock(); 456 457 /* Process request with signals blocked. */ 458 sigprocmask(SIG_SETMASK, &allowed_mask, NULL); 459 460 svc_process(rqstp); 461 462 /* Unlock export hash tables */ 463 exp_readunlock(); 464 update_thread_usage(atomic_read(&nfsd_busy)); 465 atomic_dec(&nfsd_busy); 466 } 467 468 if (err != -EINTR) { 469 printk(KERN_WARNING "nfsd: terminating on error %d\n", -err); 470 } else { 471 unsigned int signo; 472 473 for (signo = 1; signo <= _NSIG; signo++) 474 if (sigismember(¤t->pending.signal, signo) && 475 !sigismember(¤t->blocked, signo)) 476 break; 477 killsig = signo; 478 } 479 /* Clear signals before calling svc_exit_thread() */ 480 flush_signals(current); 481 482 lock_kernel(); 483 484 nfsdstats.th_cnt --; 485 486 out: 487 /* Release the thread */ 488 svc_exit_thread(rqstp); 489 490 /* Release module */ 491 unlock_kernel(); 492 module_put_and_exit(0); 493 } 494 495 static __be32 map_new_errors(u32 vers, __be32 nfserr) 496 { 497 if (nfserr == nfserr_jukebox && vers == 2) 498 return nfserr_dropit; 499 if (nfserr == nfserr_wrongsec && vers < 4) 500 return nfserr_acces; 501 return nfserr; 502 } 503 504 int 505 nfsd_dispatch(struct svc_rqst *rqstp, __be32 *statp) 506 { 507 struct svc_procedure *proc; 508 kxdrproc_t xdr; 509 __be32 nfserr; 510 __be32 *nfserrp; 511 512 dprintk("nfsd_dispatch: vers %d proc %d\n", 513 rqstp->rq_vers, rqstp->rq_proc); 514 proc = rqstp->rq_procinfo; 515 516 /* Check whether we have this call in the cache. */ 517 switch (nfsd_cache_lookup(rqstp, proc->pc_cachetype)) { 518 case RC_INTR: 519 case RC_DROPIT: 520 return 0; 521 case RC_REPLY: 522 return 1; 523 case RC_DOIT:; 524 /* do it */ 525 } 526 527 /* Decode arguments */ 528 xdr = proc->pc_decode; 529 if (xdr && !xdr(rqstp, (__be32*)rqstp->rq_arg.head[0].iov_base, 530 rqstp->rq_argp)) { 531 dprintk("nfsd: failed to decode arguments!\n"); 532 nfsd_cache_update(rqstp, RC_NOCACHE, NULL); 533 *statp = rpc_garbage_args; 534 return 1; 535 } 536 537 /* need to grab the location to store the status, as 538 * nfsv4 does some encoding while processing 539 */ 540 nfserrp = rqstp->rq_res.head[0].iov_base 541 + rqstp->rq_res.head[0].iov_len; 542 rqstp->rq_res.head[0].iov_len += sizeof(__be32); 543 544 /* Now call the procedure handler, and encode NFS status. */ 545 nfserr = proc->pc_func(rqstp, rqstp->rq_argp, rqstp->rq_resp); 546 nfserr = map_new_errors(rqstp->rq_vers, nfserr); 547 if (nfserr == nfserr_dropit) { 548 dprintk("nfsd: Dropping request; may be revisited later\n"); 549 nfsd_cache_update(rqstp, RC_NOCACHE, NULL); 550 return 0; 551 } 552 553 if (rqstp->rq_proc != 0) 554 *nfserrp++ = nfserr; 555 556 /* Encode result. 557 * For NFSv2, additional info is never returned in case of an error. 558 */ 559 if (!(nfserr && rqstp->rq_vers == 2)) { 560 xdr = proc->pc_encode; 561 if (xdr && !xdr(rqstp, nfserrp, 562 rqstp->rq_resp)) { 563 /* Failed to encode result. Release cache entry */ 564 dprintk("nfsd: failed to encode result!\n"); 565 nfsd_cache_update(rqstp, RC_NOCACHE, NULL); 566 *statp = rpc_system_err; 567 return 1; 568 } 569 } 570 571 /* Store reply in cache. */ 572 nfsd_cache_update(rqstp, proc->pc_cachetype, statp + 1); 573 return 1; 574 } 575