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 #include <linux/swap.h> 26 27 #include <linux/sunrpc/types.h> 28 #include <linux/sunrpc/stats.h> 29 #include <linux/sunrpc/svc.h> 30 #include <linux/sunrpc/svcsock.h> 31 #include <linux/sunrpc/cache.h> 32 #include <linux/nfsd/nfsd.h> 33 #include <linux/nfsd/stats.h> 34 #include <linux/nfsd/cache.h> 35 #include <linux/nfsd/syscall.h> 36 #include <linux/lockd/bind.h> 37 #include <linux/nfsacl.h> 38 39 #define NFSDDBG_FACILITY NFSDDBG_SVC 40 41 extern struct svc_program nfsd_program; 42 static int nfsd(void *vrqstp); 43 struct timeval nfssvc_boot; 44 45 /* 46 * nfsd_mutex protects nfsd_serv -- both the pointer itself and the members 47 * of the svc_serv struct. In particular, ->sv_nrthreads but also to some 48 * extent ->sv_temp_socks and ->sv_permsocks. It also protects nfsdstats.th_cnt 49 * 50 * If (out side the lock) nfsd_serv is non-NULL, then it must point to a 51 * properly initialised 'struct svc_serv' with ->sv_nrthreads > 0. That number 52 * of nfsd threads must exist and each must listed in ->sp_all_threads in each 53 * entry of ->sv_pools[]. 54 * 55 * Transitions of the thread count between zero and non-zero are of particular 56 * interest since the svc_serv needs to be created and initialized at that 57 * point, or freed. 58 * 59 * Finally, the nfsd_mutex also protects some of the global variables that are 60 * accessed when nfsd starts and that are settable via the write_* routines in 61 * nfsctl.c. In particular: 62 * 63 * user_recovery_dirname 64 * user_lease_time 65 * nfsd_versions 66 */ 67 DEFINE_MUTEX(nfsd_mutex); 68 struct svc_serv *nfsd_serv; 69 70 #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL) 71 static struct svc_stat nfsd_acl_svcstats; 72 static struct svc_version * nfsd_acl_version[] = { 73 [2] = &nfsd_acl_version2, 74 [3] = &nfsd_acl_version3, 75 }; 76 77 #define NFSD_ACL_MINVERS 2 78 #define NFSD_ACL_NRVERS ARRAY_SIZE(nfsd_acl_version) 79 static struct svc_version *nfsd_acl_versions[NFSD_ACL_NRVERS]; 80 81 static struct svc_program nfsd_acl_program = { 82 .pg_prog = NFS_ACL_PROGRAM, 83 .pg_nvers = NFSD_ACL_NRVERS, 84 .pg_vers = nfsd_acl_versions, 85 .pg_name = "nfsacl", 86 .pg_class = "nfsd", 87 .pg_stats = &nfsd_acl_svcstats, 88 .pg_authenticate = &svc_set_client, 89 }; 90 91 static struct svc_stat nfsd_acl_svcstats = { 92 .program = &nfsd_acl_program, 93 }; 94 #endif /* defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL) */ 95 96 static struct svc_version * nfsd_version[] = { 97 [2] = &nfsd_version2, 98 #if defined(CONFIG_NFSD_V3) 99 [3] = &nfsd_version3, 100 #endif 101 #if defined(CONFIG_NFSD_V4) 102 [4] = &nfsd_version4, 103 #endif 104 }; 105 106 #define NFSD_MINVERS 2 107 #define NFSD_NRVERS ARRAY_SIZE(nfsd_version) 108 static struct svc_version *nfsd_versions[NFSD_NRVERS]; 109 110 struct svc_program nfsd_program = { 111 #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL) 112 .pg_next = &nfsd_acl_program, 113 #endif 114 .pg_prog = NFS_PROGRAM, /* program number */ 115 .pg_nvers = NFSD_NRVERS, /* nr of entries in nfsd_version */ 116 .pg_vers = nfsd_versions, /* version table */ 117 .pg_name = "nfsd", /* program name */ 118 .pg_class = "nfsd", /* authentication class */ 119 .pg_stats = &nfsd_svcstats, /* version table */ 120 .pg_authenticate = &svc_set_client, /* export authentication */ 121 122 }; 123 124 u32 nfsd_supported_minorversion; 125 126 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 int nfsd_minorversion(u32 minorversion, enum vers_op change) 154 { 155 if (minorversion > NFSD_SUPPORTED_MINOR_VERSION) 156 return -1; 157 switch(change) { 158 case NFSD_SET: 159 nfsd_supported_minorversion = minorversion; 160 break; 161 case NFSD_CLEAR: 162 if (minorversion == 0) 163 return -1; 164 nfsd_supported_minorversion = minorversion - 1; 165 break; 166 case NFSD_TEST: 167 return minorversion <= nfsd_supported_minorversion; 168 case NFSD_AVAIL: 169 return minorversion <= NFSD_SUPPORTED_MINOR_VERSION; 170 } 171 return 0; 172 } 173 174 /* 175 * Maximum number of nfsd processes 176 */ 177 #define NFSD_MAXSERVS 8192 178 179 int nfsd_nrthreads(void) 180 { 181 int rv = 0; 182 mutex_lock(&nfsd_mutex); 183 if (nfsd_serv) 184 rv = nfsd_serv->sv_nrthreads; 185 mutex_unlock(&nfsd_mutex); 186 return rv; 187 } 188 189 static void nfsd_last_thread(struct svc_serv *serv) 190 { 191 /* When last nfsd thread exits we need to do some clean-up */ 192 struct svc_xprt *xprt; 193 list_for_each_entry(xprt, &serv->sv_permsocks, xpt_list) 194 lockd_down(); 195 nfsd_serv = NULL; 196 nfsd_racache_shutdown(); 197 nfs4_state_shutdown(); 198 199 printk(KERN_WARNING "nfsd: last server has exited, flushing export " 200 "cache\n"); 201 nfsd_export_flush(); 202 } 203 204 void nfsd_reset_versions(void) 205 { 206 int found_one = 0; 207 int i; 208 209 for (i = NFSD_MINVERS; i < NFSD_NRVERS; i++) { 210 if (nfsd_program.pg_vers[i]) 211 found_one = 1; 212 } 213 214 if (!found_one) { 215 for (i = NFSD_MINVERS; i < NFSD_NRVERS; i++) 216 nfsd_program.pg_vers[i] = nfsd_version[i]; 217 #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL) 218 for (i = NFSD_ACL_MINVERS; i < NFSD_ACL_NRVERS; i++) 219 nfsd_acl_program.pg_vers[i] = 220 nfsd_acl_version[i]; 221 #endif 222 } 223 } 224 225 /* 226 * Each session guarantees a negotiated per slot memory cache for replies 227 * which in turn consumes memory beyond the v2/v3/v4.0 server. A dedicated 228 * NFSv4.1 server might want to use more memory for a DRC than a machine 229 * with mutiple services. 230 * 231 * Impose a hard limit on the number of pages for the DRC which varies 232 * according to the machines free pages. This is of course only a default. 233 * 234 * For now this is a #defined shift which could be under admin control 235 * in the future. 236 */ 237 static void set_max_drc(void) 238 { 239 /* The percent of nr_free_buffer_pages used by the V4.1 server DRC */ 240 #define NFSD_DRC_SIZE_SHIFT 7 241 nfsd_serv->sv_drc_max_pages = nr_free_buffer_pages() 242 >> NFSD_DRC_SIZE_SHIFT; 243 nfsd_serv->sv_drc_pages_used = 0; 244 dprintk("%s svc_drc_max_pages %u\n", __func__, 245 nfsd_serv->sv_drc_max_pages); 246 } 247 248 int nfsd_create_serv(void) 249 { 250 int err = 0; 251 252 WARN_ON(!mutex_is_locked(&nfsd_mutex)); 253 if (nfsd_serv) { 254 svc_get(nfsd_serv); 255 return 0; 256 } 257 if (nfsd_max_blksize == 0) { 258 /* choose a suitable default */ 259 struct sysinfo i; 260 si_meminfo(&i); 261 /* Aim for 1/4096 of memory per thread 262 * This gives 1MB on 4Gig machines 263 * But only uses 32K on 128M machines. 264 * Bottom out at 8K on 32M and smaller. 265 * Of course, this is only a default. 266 */ 267 nfsd_max_blksize = NFSSVC_MAXBLKSIZE; 268 i.totalram <<= PAGE_SHIFT - 12; 269 while (nfsd_max_blksize > i.totalram && 270 nfsd_max_blksize >= 8*1024*2) 271 nfsd_max_blksize /= 2; 272 } 273 274 nfsd_serv = svc_create_pooled(&nfsd_program, nfsd_max_blksize, 275 nfsd_last_thread, nfsd, THIS_MODULE); 276 if (nfsd_serv == NULL) 277 err = -ENOMEM; 278 else 279 set_max_drc(); 280 281 do_gettimeofday(&nfssvc_boot); /* record boot time */ 282 return err; 283 } 284 285 static int nfsd_init_socks(int port) 286 { 287 int error; 288 if (!list_empty(&nfsd_serv->sv_permsocks)) 289 return 0; 290 291 error = svc_create_xprt(nfsd_serv, "udp", PF_INET, port, 292 SVC_SOCK_DEFAULTS); 293 if (error < 0) 294 return error; 295 296 error = lockd_up(); 297 if (error < 0) 298 return error; 299 300 error = svc_create_xprt(nfsd_serv, "tcp", PF_INET, port, 301 SVC_SOCK_DEFAULTS); 302 if (error < 0) 303 return error; 304 305 error = lockd_up(); 306 if (error < 0) 307 return error; 308 309 return 0; 310 } 311 312 int nfsd_nrpools(void) 313 { 314 if (nfsd_serv == NULL) 315 return 0; 316 else 317 return nfsd_serv->sv_nrpools; 318 } 319 320 int nfsd_get_nrthreads(int n, int *nthreads) 321 { 322 int i = 0; 323 324 if (nfsd_serv != NULL) { 325 for (i = 0; i < nfsd_serv->sv_nrpools && i < n; i++) 326 nthreads[i] = nfsd_serv->sv_pools[i].sp_nrthreads; 327 } 328 329 return 0; 330 } 331 332 int nfsd_set_nrthreads(int n, int *nthreads) 333 { 334 int i = 0; 335 int tot = 0; 336 int err = 0; 337 338 WARN_ON(!mutex_is_locked(&nfsd_mutex)); 339 340 if (nfsd_serv == NULL || n <= 0) 341 return 0; 342 343 if (n > nfsd_serv->sv_nrpools) 344 n = nfsd_serv->sv_nrpools; 345 346 /* enforce a global maximum number of threads */ 347 tot = 0; 348 for (i = 0; i < n; i++) { 349 if (nthreads[i] > NFSD_MAXSERVS) 350 nthreads[i] = NFSD_MAXSERVS; 351 tot += nthreads[i]; 352 } 353 if (tot > NFSD_MAXSERVS) { 354 /* total too large: scale down requested numbers */ 355 for (i = 0; i < n && tot > 0; i++) { 356 int new = nthreads[i] * NFSD_MAXSERVS / tot; 357 tot -= (nthreads[i] - new); 358 nthreads[i] = new; 359 } 360 for (i = 0; i < n && tot > 0; i++) { 361 nthreads[i]--; 362 tot--; 363 } 364 } 365 366 /* 367 * There must always be a thread in pool 0; the admin 368 * can't shut down NFS completely using pool_threads. 369 */ 370 if (nthreads[0] == 0) 371 nthreads[0] = 1; 372 373 /* apply the new numbers */ 374 svc_get(nfsd_serv); 375 for (i = 0; i < n; i++) { 376 err = svc_set_num_threads(nfsd_serv, &nfsd_serv->sv_pools[i], 377 nthreads[i]); 378 if (err) 379 break; 380 } 381 svc_destroy(nfsd_serv); 382 383 return err; 384 } 385 386 int 387 nfsd_svc(unsigned short port, int nrservs) 388 { 389 int error; 390 391 mutex_lock(&nfsd_mutex); 392 dprintk("nfsd: creating service\n"); 393 error = -EINVAL; 394 if (nrservs <= 0) 395 nrservs = 0; 396 if (nrservs > NFSD_MAXSERVS) 397 nrservs = NFSD_MAXSERVS; 398 399 /* Readahead param cache - will no-op if it already exists */ 400 error = nfsd_racache_init(2*nrservs); 401 if (error<0) 402 goto out; 403 nfs4_state_start(); 404 405 nfsd_reset_versions(); 406 407 error = nfsd_create_serv(); 408 409 if (error) 410 goto out; 411 error = nfsd_init_socks(port); 412 if (error) 413 goto failure; 414 415 error = svc_set_num_threads(nfsd_serv, NULL, nrservs); 416 failure: 417 svc_destroy(nfsd_serv); /* Release server */ 418 out: 419 mutex_unlock(&nfsd_mutex); 420 return error; 421 } 422 423 424 /* 425 * This is the NFS server kernel thread 426 */ 427 static int 428 nfsd(void *vrqstp) 429 { 430 struct svc_rqst *rqstp = (struct svc_rqst *) vrqstp; 431 int err, preverr = 0; 432 433 /* Lock module and set up kernel thread */ 434 mutex_lock(&nfsd_mutex); 435 436 /* At this point, the thread shares current->fs 437 * with the init process. We need to create files with a 438 * umask of 0 instead of init's umask. */ 439 if (unshare_fs_struct() < 0) { 440 printk("Unable to start nfsd thread: out of memory\n"); 441 goto out; 442 } 443 444 current->fs->umask = 0; 445 446 /* 447 * thread is spawned with all signals set to SIG_IGN, re-enable 448 * the ones that will bring down the thread 449 */ 450 allow_signal(SIGKILL); 451 allow_signal(SIGHUP); 452 allow_signal(SIGINT); 453 allow_signal(SIGQUIT); 454 455 nfsdstats.th_cnt++; 456 mutex_unlock(&nfsd_mutex); 457 458 /* 459 * We want less throttling in balance_dirty_pages() so that nfs to 460 * localhost doesn't cause nfsd to lock up due to all the client's 461 * dirty pages. 462 */ 463 current->flags |= PF_LESS_THROTTLE; 464 set_freezable(); 465 466 /* 467 * The main request loop 468 */ 469 for (;;) { 470 /* 471 * Find a socket with data available and call its 472 * recvfrom routine. 473 */ 474 while ((err = svc_recv(rqstp, 60*60*HZ)) == -EAGAIN) 475 ; 476 if (err == -EINTR) 477 break; 478 else if (err < 0) { 479 if (err != preverr) { 480 printk(KERN_WARNING "%s: unexpected error " 481 "from svc_recv (%d)\n", __func__, -err); 482 preverr = err; 483 } 484 schedule_timeout_uninterruptible(HZ); 485 continue; 486 } 487 488 489 /* Lock the export hash tables for reading. */ 490 exp_readlock(); 491 492 svc_process(rqstp); 493 494 /* Unlock export hash tables */ 495 exp_readunlock(); 496 } 497 498 /* Clear signals before calling svc_exit_thread() */ 499 flush_signals(current); 500 501 mutex_lock(&nfsd_mutex); 502 nfsdstats.th_cnt --; 503 504 out: 505 /* Release the thread */ 506 svc_exit_thread(rqstp); 507 508 /* Release module */ 509 mutex_unlock(&nfsd_mutex); 510 module_put_and_exit(0); 511 return 0; 512 } 513 514 static __be32 map_new_errors(u32 vers, __be32 nfserr) 515 { 516 if (nfserr == nfserr_jukebox && vers == 2) 517 return nfserr_dropit; 518 if (nfserr == nfserr_wrongsec && vers < 4) 519 return nfserr_acces; 520 return nfserr; 521 } 522 523 int 524 nfsd_dispatch(struct svc_rqst *rqstp, __be32 *statp) 525 { 526 struct svc_procedure *proc; 527 kxdrproc_t xdr; 528 __be32 nfserr; 529 __be32 *nfserrp; 530 531 dprintk("nfsd_dispatch: vers %d proc %d\n", 532 rqstp->rq_vers, rqstp->rq_proc); 533 proc = rqstp->rq_procinfo; 534 535 /* Check whether we have this call in the cache. */ 536 switch (nfsd_cache_lookup(rqstp, proc->pc_cachetype)) { 537 case RC_INTR: 538 case RC_DROPIT: 539 return 0; 540 case RC_REPLY: 541 return 1; 542 case RC_DOIT:; 543 /* do it */ 544 } 545 546 /* Decode arguments */ 547 xdr = proc->pc_decode; 548 if (xdr && !xdr(rqstp, (__be32*)rqstp->rq_arg.head[0].iov_base, 549 rqstp->rq_argp)) { 550 dprintk("nfsd: failed to decode arguments!\n"); 551 nfsd_cache_update(rqstp, RC_NOCACHE, NULL); 552 *statp = rpc_garbage_args; 553 return 1; 554 } 555 556 /* need to grab the location to store the status, as 557 * nfsv4 does some encoding while processing 558 */ 559 nfserrp = rqstp->rq_res.head[0].iov_base 560 + rqstp->rq_res.head[0].iov_len; 561 rqstp->rq_res.head[0].iov_len += sizeof(__be32); 562 563 /* NFSv4.1 DRC requires statp */ 564 if (rqstp->rq_vers == 4) 565 nfsd4_set_statp(rqstp, statp); 566 567 /* Now call the procedure handler, and encode NFS status. */ 568 nfserr = proc->pc_func(rqstp, rqstp->rq_argp, rqstp->rq_resp); 569 nfserr = map_new_errors(rqstp->rq_vers, nfserr); 570 if (nfserr == nfserr_dropit) { 571 dprintk("nfsd: Dropping request; may be revisited later\n"); 572 nfsd_cache_update(rqstp, RC_NOCACHE, NULL); 573 return 0; 574 } 575 576 if (rqstp->rq_proc != 0) 577 *nfserrp++ = nfserr; 578 579 /* Encode result. 580 * For NFSv2, additional info is never returned in case of an error. 581 */ 582 if (!(nfserr && rqstp->rq_vers == 2)) { 583 xdr = proc->pc_encode; 584 if (xdr && !xdr(rqstp, nfserrp, 585 rqstp->rq_resp)) { 586 /* Failed to encode result. Release cache entry */ 587 dprintk("nfsd: failed to encode result!\n"); 588 nfsd_cache_update(rqstp, RC_NOCACHE, NULL); 589 *statp = rpc_system_err; 590 return 1; 591 } 592 } 593 594 /* Store reply in cache. */ 595 nfsd_cache_update(rqstp, proc->pc_cachetype, statp + 1); 596 return 1; 597 } 598 599 int nfsd_pool_stats_open(struct inode *inode, struct file *file) 600 { 601 if (nfsd_serv == NULL) 602 return -ENODEV; 603 return svc_pool_stats_open(nfsd_serv, file); 604 } 605