1 /* 2 * Central processing for nfsd. 3 * 4 * Authors: Olaf Kirch (okir@monad.swb.de) 5 * 6 * Copyright (C) 1995, 1996, 1997 Olaf Kirch <okir@monad.swb.de> 7 */ 8 9 #include <linux/sched/signal.h> 10 #include <linux/freezer.h> 11 #include <linux/module.h> 12 #include <linux/fs_struct.h> 13 #include <linux/swap.h> 14 15 #include <linux/sunrpc/stats.h> 16 #include <linux/sunrpc/svcsock.h> 17 #include <linux/sunrpc/svc_xprt.h> 18 #include <linux/lockd/bind.h> 19 #include <linux/nfsacl.h> 20 #include <linux/seq_file.h> 21 #include <linux/inetdevice.h> 22 #include <net/addrconf.h> 23 #include <net/ipv6.h> 24 #include <net/net_namespace.h> 25 #include "nfsd.h" 26 #include "cache.h" 27 #include "vfs.h" 28 #include "netns.h" 29 30 #define NFSDDBG_FACILITY NFSDDBG_SVC 31 32 extern struct svc_program nfsd_program; 33 static int nfsd(void *vrqstp); 34 35 /* 36 * nfsd_mutex protects nn->nfsd_serv -- both the pointer itself and the members 37 * of the svc_serv struct. In particular, ->sv_nrthreads but also to some 38 * extent ->sv_temp_socks and ->sv_permsocks. It also protects nfsdstats.th_cnt 39 * 40 * If (out side the lock) nn->nfsd_serv is non-NULL, then it must point to a 41 * properly initialised 'struct svc_serv' with ->sv_nrthreads > 0. That number 42 * of nfsd threads must exist and each must listed in ->sp_all_threads in each 43 * entry of ->sv_pools[]. 44 * 45 * Transitions of the thread count between zero and non-zero are of particular 46 * interest since the svc_serv needs to be created and initialized at that 47 * point, or freed. 48 * 49 * Finally, the nfsd_mutex also protects some of the global variables that are 50 * accessed when nfsd starts and that are settable via the write_* routines in 51 * nfsctl.c. In particular: 52 * 53 * user_recovery_dirname 54 * user_lease_time 55 * nfsd_versions 56 */ 57 DEFINE_MUTEX(nfsd_mutex); 58 59 /* 60 * nfsd_drc_lock protects nfsd_drc_max_pages and nfsd_drc_pages_used. 61 * nfsd_drc_max_pages limits the total amount of memory available for 62 * version 4.1 DRC caches. 63 * nfsd_drc_pages_used tracks the current version 4.1 DRC memory usage. 64 */ 65 spinlock_t nfsd_drc_lock; 66 unsigned long nfsd_drc_max_mem; 67 unsigned long nfsd_drc_mem_used; 68 69 #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL) 70 static struct svc_stat nfsd_acl_svcstats; 71 static struct svc_version * nfsd_acl_version[] = { 72 [2] = &nfsd_acl_version2, 73 [3] = &nfsd_acl_version3, 74 }; 75 76 #define NFSD_ACL_MINVERS 2 77 #define NFSD_ACL_NRVERS ARRAY_SIZE(nfsd_acl_version) 78 static struct svc_version *nfsd_acl_versions[NFSD_ACL_NRVERS]; 79 80 static struct svc_program nfsd_acl_program = { 81 .pg_prog = NFS_ACL_PROGRAM, 82 .pg_nvers = NFSD_ACL_NRVERS, 83 .pg_vers = nfsd_acl_versions, 84 .pg_name = "nfsacl", 85 .pg_class = "nfsd", 86 .pg_stats = &nfsd_acl_svcstats, 87 .pg_authenticate = &svc_set_client, 88 }; 89 90 static struct svc_stat nfsd_acl_svcstats = { 91 .program = &nfsd_acl_program, 92 }; 93 #endif /* defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL) */ 94 95 static struct svc_version * nfsd_version[] = { 96 [2] = &nfsd_version2, 97 #if defined(CONFIG_NFSD_V3) 98 [3] = &nfsd_version3, 99 #endif 100 #if defined(CONFIG_NFSD_V4) 101 [4] = &nfsd_version4, 102 #endif 103 }; 104 105 #define NFSD_MINVERS 2 106 #define NFSD_NRVERS ARRAY_SIZE(nfsd_version) 107 static struct svc_version *nfsd_versions[NFSD_NRVERS]; 108 109 struct svc_program nfsd_program = { 110 #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL) 111 .pg_next = &nfsd_acl_program, 112 #endif 113 .pg_prog = NFS_PROGRAM, /* program number */ 114 .pg_nvers = NFSD_NRVERS, /* nr of entries in nfsd_version */ 115 .pg_vers = nfsd_versions, /* version table */ 116 .pg_name = "nfsd", /* program name */ 117 .pg_class = "nfsd", /* authentication class */ 118 .pg_stats = &nfsd_svcstats, /* version table */ 119 .pg_authenticate = &svc_set_client, /* export authentication */ 120 121 }; 122 123 static bool nfsd_supported_minorversions[NFSD_SUPPORTED_MINOR_VERSION + 1] = { 124 [0] = 1, 125 [1] = 1, 126 [2] = 1, 127 }; 128 129 int nfsd_vers(int vers, enum vers_op change) 130 { 131 if (vers < NFSD_MINVERS || vers >= NFSD_NRVERS) 132 return 0; 133 switch(change) { 134 case NFSD_SET: 135 nfsd_versions[vers] = nfsd_version[vers]; 136 #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL) 137 if (vers < NFSD_ACL_NRVERS) 138 nfsd_acl_versions[vers] = nfsd_acl_version[vers]; 139 #endif 140 break; 141 case NFSD_CLEAR: 142 nfsd_versions[vers] = NULL; 143 #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL) 144 if (vers < NFSD_ACL_NRVERS) 145 nfsd_acl_versions[vers] = NULL; 146 #endif 147 break; 148 case NFSD_TEST: 149 return nfsd_versions[vers] != NULL; 150 case NFSD_AVAIL: 151 return nfsd_version[vers] != NULL; 152 } 153 return 0; 154 } 155 156 static void 157 nfsd_adjust_nfsd_versions4(void) 158 { 159 unsigned i; 160 161 for (i = 0; i <= NFSD_SUPPORTED_MINOR_VERSION; i++) { 162 if (nfsd_supported_minorversions[i]) 163 return; 164 } 165 nfsd_vers(4, NFSD_CLEAR); 166 } 167 168 int nfsd_minorversion(u32 minorversion, enum vers_op change) 169 { 170 if (minorversion > NFSD_SUPPORTED_MINOR_VERSION && 171 change != NFSD_AVAIL) 172 return -1; 173 switch(change) { 174 case NFSD_SET: 175 nfsd_supported_minorversions[minorversion] = true; 176 nfsd_vers(4, NFSD_SET); 177 break; 178 case NFSD_CLEAR: 179 nfsd_supported_minorversions[minorversion] = false; 180 nfsd_adjust_nfsd_versions4(); 181 break; 182 case NFSD_TEST: 183 return nfsd_supported_minorversions[minorversion]; 184 case NFSD_AVAIL: 185 return minorversion <= NFSD_SUPPORTED_MINOR_VERSION; 186 } 187 return 0; 188 } 189 190 /* 191 * Maximum number of nfsd processes 192 */ 193 #define NFSD_MAXSERVS 8192 194 195 int nfsd_nrthreads(struct net *net) 196 { 197 int rv = 0; 198 struct nfsd_net *nn = net_generic(net, nfsd_net_id); 199 200 mutex_lock(&nfsd_mutex); 201 if (nn->nfsd_serv) 202 rv = nn->nfsd_serv->sv_nrthreads; 203 mutex_unlock(&nfsd_mutex); 204 return rv; 205 } 206 207 static int nfsd_init_socks(struct net *net) 208 { 209 int error; 210 struct nfsd_net *nn = net_generic(net, nfsd_net_id); 211 212 if (!list_empty(&nn->nfsd_serv->sv_permsocks)) 213 return 0; 214 215 error = svc_create_xprt(nn->nfsd_serv, "udp", net, PF_INET, NFS_PORT, 216 SVC_SOCK_DEFAULTS); 217 if (error < 0) 218 return error; 219 220 error = svc_create_xprt(nn->nfsd_serv, "tcp", net, PF_INET, NFS_PORT, 221 SVC_SOCK_DEFAULTS); 222 if (error < 0) 223 return error; 224 225 return 0; 226 } 227 228 static int nfsd_users = 0; 229 230 static int nfsd_startup_generic(int nrservs) 231 { 232 int ret; 233 234 if (nfsd_users++) 235 return 0; 236 237 /* 238 * Readahead param cache - will no-op if it already exists. 239 * (Note therefore results will be suboptimal if number of 240 * threads is modified after nfsd start.) 241 */ 242 ret = nfsd_racache_init(2*nrservs); 243 if (ret) 244 goto dec_users; 245 246 ret = nfs4_state_start(); 247 if (ret) 248 goto out_racache; 249 return 0; 250 251 out_racache: 252 nfsd_racache_shutdown(); 253 dec_users: 254 nfsd_users--; 255 return ret; 256 } 257 258 static void nfsd_shutdown_generic(void) 259 { 260 if (--nfsd_users) 261 return; 262 263 nfs4_state_shutdown(); 264 nfsd_racache_shutdown(); 265 } 266 267 static bool nfsd_needs_lockd(void) 268 { 269 #if defined(CONFIG_NFSD_V3) 270 return (nfsd_versions[2] != NULL) || (nfsd_versions[3] != NULL); 271 #else 272 return (nfsd_versions[2] != NULL); 273 #endif 274 } 275 276 static int nfsd_startup_net(int nrservs, struct net *net) 277 { 278 struct nfsd_net *nn = net_generic(net, nfsd_net_id); 279 int ret; 280 281 if (nn->nfsd_net_up) 282 return 0; 283 284 ret = nfsd_startup_generic(nrservs); 285 if (ret) 286 return ret; 287 ret = nfsd_init_socks(net); 288 if (ret) 289 goto out_socks; 290 291 if (nfsd_needs_lockd() && !nn->lockd_up) { 292 ret = lockd_up(net); 293 if (ret) 294 goto out_socks; 295 nn->lockd_up = 1; 296 } 297 298 ret = nfs4_state_start_net(net); 299 if (ret) 300 goto out_lockd; 301 302 nn->nfsd_net_up = true; 303 return 0; 304 305 out_lockd: 306 if (nn->lockd_up) { 307 lockd_down(net); 308 nn->lockd_up = 0; 309 } 310 out_socks: 311 nfsd_shutdown_generic(); 312 return ret; 313 } 314 315 static void nfsd_shutdown_net(struct net *net) 316 { 317 struct nfsd_net *nn = net_generic(net, nfsd_net_id); 318 319 nfs4_state_shutdown_net(net); 320 if (nn->lockd_up) { 321 lockd_down(net); 322 nn->lockd_up = 0; 323 } 324 nn->nfsd_net_up = false; 325 nfsd_shutdown_generic(); 326 } 327 328 static int nfsd_inetaddr_event(struct notifier_block *this, unsigned long event, 329 void *ptr) 330 { 331 struct in_ifaddr *ifa = (struct in_ifaddr *)ptr; 332 struct net_device *dev = ifa->ifa_dev->dev; 333 struct net *net = dev_net(dev); 334 struct nfsd_net *nn = net_generic(net, nfsd_net_id); 335 struct sockaddr_in sin; 336 337 if (event != NETDEV_DOWN) 338 goto out; 339 340 if (nn->nfsd_serv) { 341 dprintk("nfsd_inetaddr_event: removed %pI4\n", &ifa->ifa_local); 342 sin.sin_family = AF_INET; 343 sin.sin_addr.s_addr = ifa->ifa_local; 344 svc_age_temp_xprts_now(nn->nfsd_serv, (struct sockaddr *)&sin); 345 } 346 347 out: 348 return NOTIFY_DONE; 349 } 350 351 static struct notifier_block nfsd_inetaddr_notifier = { 352 .notifier_call = nfsd_inetaddr_event, 353 }; 354 355 #if IS_ENABLED(CONFIG_IPV6) 356 static int nfsd_inet6addr_event(struct notifier_block *this, 357 unsigned long event, void *ptr) 358 { 359 struct inet6_ifaddr *ifa = (struct inet6_ifaddr *)ptr; 360 struct net_device *dev = ifa->idev->dev; 361 struct net *net = dev_net(dev); 362 struct nfsd_net *nn = net_generic(net, nfsd_net_id); 363 struct sockaddr_in6 sin6; 364 365 if (event != NETDEV_DOWN) 366 goto out; 367 368 if (nn->nfsd_serv) { 369 dprintk("nfsd_inet6addr_event: removed %pI6\n", &ifa->addr); 370 sin6.sin6_family = AF_INET6; 371 sin6.sin6_addr = ifa->addr; 372 if (ipv6_addr_type(&sin6.sin6_addr) & IPV6_ADDR_LINKLOCAL) 373 sin6.sin6_scope_id = ifa->idev->dev->ifindex; 374 svc_age_temp_xprts_now(nn->nfsd_serv, (struct sockaddr *)&sin6); 375 } 376 377 out: 378 return NOTIFY_DONE; 379 } 380 381 static struct notifier_block nfsd_inet6addr_notifier = { 382 .notifier_call = nfsd_inet6addr_event, 383 }; 384 #endif 385 386 /* Only used under nfsd_mutex, so this atomic may be overkill: */ 387 static atomic_t nfsd_notifier_refcount = ATOMIC_INIT(0); 388 389 static void nfsd_last_thread(struct svc_serv *serv, struct net *net) 390 { 391 struct nfsd_net *nn = net_generic(net, nfsd_net_id); 392 393 /* check if the notifier still has clients */ 394 if (atomic_dec_return(&nfsd_notifier_refcount) == 0) { 395 unregister_inetaddr_notifier(&nfsd_inetaddr_notifier); 396 #if IS_ENABLED(CONFIG_IPV6) 397 unregister_inet6addr_notifier(&nfsd_inet6addr_notifier); 398 #endif 399 } 400 401 /* 402 * write_ports can create the server without actually starting 403 * any threads--if we get shut down before any threads are 404 * started, then nfsd_last_thread will be run before any of this 405 * other initialization has been done except the rpcb information. 406 */ 407 svc_rpcb_cleanup(serv, net); 408 if (!nn->nfsd_net_up) 409 return; 410 411 nfsd_shutdown_net(net); 412 printk(KERN_WARNING "nfsd: last server has exited, flushing export " 413 "cache\n"); 414 nfsd_export_flush(net); 415 } 416 417 void nfsd_reset_versions(void) 418 { 419 int i; 420 421 for (i = 0; i < NFSD_NRVERS; i++) 422 if (nfsd_vers(i, NFSD_TEST)) 423 return; 424 425 for (i = 0; i < NFSD_NRVERS; i++) 426 if (i != 4) 427 nfsd_vers(i, NFSD_SET); 428 else { 429 int minor = 0; 430 while (nfsd_minorversion(minor, NFSD_SET) >= 0) 431 minor++; 432 } 433 } 434 435 /* 436 * Each session guarantees a negotiated per slot memory cache for replies 437 * which in turn consumes memory beyond the v2/v3/v4.0 server. A dedicated 438 * NFSv4.1 server might want to use more memory for a DRC than a machine 439 * with mutiple services. 440 * 441 * Impose a hard limit on the number of pages for the DRC which varies 442 * according to the machines free pages. This is of course only a default. 443 * 444 * For now this is a #defined shift which could be under admin control 445 * in the future. 446 */ 447 static void set_max_drc(void) 448 { 449 #define NFSD_DRC_SIZE_SHIFT 10 450 nfsd_drc_max_mem = (nr_free_buffer_pages() 451 >> NFSD_DRC_SIZE_SHIFT) * PAGE_SIZE; 452 nfsd_drc_mem_used = 0; 453 spin_lock_init(&nfsd_drc_lock); 454 dprintk("%s nfsd_drc_max_mem %lu \n", __func__, nfsd_drc_max_mem); 455 } 456 457 static int nfsd_get_default_max_blksize(void) 458 { 459 struct sysinfo i; 460 unsigned long long target; 461 unsigned long ret; 462 463 si_meminfo(&i); 464 target = (i.totalram - i.totalhigh) << PAGE_SHIFT; 465 /* 466 * Aim for 1/4096 of memory per thread This gives 1MB on 4Gig 467 * machines, but only uses 32K on 128M machines. Bottom out at 468 * 8K on 32M and smaller. Of course, this is only a default. 469 */ 470 target >>= 12; 471 472 ret = NFSSVC_MAXBLKSIZE; 473 while (ret > target && ret >= 8*1024*2) 474 ret /= 2; 475 return ret; 476 } 477 478 static struct svc_serv_ops nfsd_thread_sv_ops = { 479 .svo_shutdown = nfsd_last_thread, 480 .svo_function = nfsd, 481 .svo_enqueue_xprt = svc_xprt_do_enqueue, 482 .svo_setup = svc_set_num_threads, 483 .svo_module = THIS_MODULE, 484 }; 485 486 int nfsd_create_serv(struct net *net) 487 { 488 int error; 489 struct nfsd_net *nn = net_generic(net, nfsd_net_id); 490 491 WARN_ON(!mutex_is_locked(&nfsd_mutex)); 492 if (nn->nfsd_serv) { 493 svc_get(nn->nfsd_serv); 494 return 0; 495 } 496 if (nfsd_max_blksize == 0) 497 nfsd_max_blksize = nfsd_get_default_max_blksize(); 498 nfsd_reset_versions(); 499 nn->nfsd_serv = svc_create_pooled(&nfsd_program, nfsd_max_blksize, 500 &nfsd_thread_sv_ops); 501 if (nn->nfsd_serv == NULL) 502 return -ENOMEM; 503 504 nn->nfsd_serv->sv_maxconn = nn->max_connections; 505 error = svc_bind(nn->nfsd_serv, net); 506 if (error < 0) { 507 svc_destroy(nn->nfsd_serv); 508 return error; 509 } 510 511 set_max_drc(); 512 /* check if the notifier is already set */ 513 if (atomic_inc_return(&nfsd_notifier_refcount) == 1) { 514 register_inetaddr_notifier(&nfsd_inetaddr_notifier); 515 #if IS_ENABLED(CONFIG_IPV6) 516 register_inet6addr_notifier(&nfsd_inet6addr_notifier); 517 #endif 518 } 519 do_gettimeofday(&nn->nfssvc_boot); /* record boot time */ 520 return 0; 521 } 522 523 int nfsd_nrpools(struct net *net) 524 { 525 struct nfsd_net *nn = net_generic(net, nfsd_net_id); 526 527 if (nn->nfsd_serv == NULL) 528 return 0; 529 else 530 return nn->nfsd_serv->sv_nrpools; 531 } 532 533 int nfsd_get_nrthreads(int n, int *nthreads, struct net *net) 534 { 535 int i = 0; 536 struct nfsd_net *nn = net_generic(net, nfsd_net_id); 537 538 if (nn->nfsd_serv != NULL) { 539 for (i = 0; i < nn->nfsd_serv->sv_nrpools && i < n; i++) 540 nthreads[i] = nn->nfsd_serv->sv_pools[i].sp_nrthreads; 541 } 542 543 return 0; 544 } 545 546 void nfsd_destroy(struct net *net) 547 { 548 struct nfsd_net *nn = net_generic(net, nfsd_net_id); 549 int destroy = (nn->nfsd_serv->sv_nrthreads == 1); 550 551 if (destroy) 552 svc_shutdown_net(nn->nfsd_serv, net); 553 svc_destroy(nn->nfsd_serv); 554 if (destroy) 555 nn->nfsd_serv = NULL; 556 } 557 558 int nfsd_set_nrthreads(int n, int *nthreads, struct net *net) 559 { 560 int i = 0; 561 int tot = 0; 562 int err = 0; 563 struct nfsd_net *nn = net_generic(net, nfsd_net_id); 564 565 WARN_ON(!mutex_is_locked(&nfsd_mutex)); 566 567 if (nn->nfsd_serv == NULL || n <= 0) 568 return 0; 569 570 if (n > nn->nfsd_serv->sv_nrpools) 571 n = nn->nfsd_serv->sv_nrpools; 572 573 /* enforce a global maximum number of threads */ 574 tot = 0; 575 for (i = 0; i < n; i++) { 576 nthreads[i] = min(nthreads[i], NFSD_MAXSERVS); 577 tot += nthreads[i]; 578 } 579 if (tot > NFSD_MAXSERVS) { 580 /* total too large: scale down requested numbers */ 581 for (i = 0; i < n && tot > 0; i++) { 582 int new = nthreads[i] * NFSD_MAXSERVS / tot; 583 tot -= (nthreads[i] - new); 584 nthreads[i] = new; 585 } 586 for (i = 0; i < n && tot > 0; i++) { 587 nthreads[i]--; 588 tot--; 589 } 590 } 591 592 /* 593 * There must always be a thread in pool 0; the admin 594 * can't shut down NFS completely using pool_threads. 595 */ 596 if (nthreads[0] == 0) 597 nthreads[0] = 1; 598 599 /* apply the new numbers */ 600 svc_get(nn->nfsd_serv); 601 for (i = 0; i < n; i++) { 602 err = nn->nfsd_serv->sv_ops->svo_setup(nn->nfsd_serv, 603 &nn->nfsd_serv->sv_pools[i], nthreads[i]); 604 if (err) 605 break; 606 } 607 nfsd_destroy(net); 608 return err; 609 } 610 611 /* 612 * Adjust the number of threads and return the new number of threads. 613 * This is also the function that starts the server if necessary, if 614 * this is the first time nrservs is nonzero. 615 */ 616 int 617 nfsd_svc(int nrservs, struct net *net) 618 { 619 int error; 620 bool nfsd_up_before; 621 struct nfsd_net *nn = net_generic(net, nfsd_net_id); 622 623 mutex_lock(&nfsd_mutex); 624 dprintk("nfsd: creating service\n"); 625 626 nrservs = max(nrservs, 0); 627 nrservs = min(nrservs, NFSD_MAXSERVS); 628 error = 0; 629 630 if (nrservs == 0 && nn->nfsd_serv == NULL) 631 goto out; 632 633 error = nfsd_create_serv(net); 634 if (error) 635 goto out; 636 637 nfsd_up_before = nn->nfsd_net_up; 638 639 error = nfsd_startup_net(nrservs, net); 640 if (error) 641 goto out_destroy; 642 error = nn->nfsd_serv->sv_ops->svo_setup(nn->nfsd_serv, 643 NULL, nrservs); 644 if (error) 645 goto out_shutdown; 646 /* We are holding a reference to nn->nfsd_serv which 647 * we don't want to count in the return value, 648 * so subtract 1 649 */ 650 error = nn->nfsd_serv->sv_nrthreads - 1; 651 out_shutdown: 652 if (error < 0 && !nfsd_up_before) 653 nfsd_shutdown_net(net); 654 out_destroy: 655 nfsd_destroy(net); /* Release server */ 656 out: 657 mutex_unlock(&nfsd_mutex); 658 return error; 659 } 660 661 662 /* 663 * This is the NFS server kernel thread 664 */ 665 static int 666 nfsd(void *vrqstp) 667 { 668 struct svc_rqst *rqstp = (struct svc_rqst *) vrqstp; 669 struct svc_xprt *perm_sock = list_entry(rqstp->rq_server->sv_permsocks.next, typeof(struct svc_xprt), xpt_list); 670 struct net *net = perm_sock->xpt_net; 671 struct nfsd_net *nn = net_generic(net, nfsd_net_id); 672 int err; 673 674 /* Lock module and set up kernel thread */ 675 mutex_lock(&nfsd_mutex); 676 677 /* At this point, the thread shares current->fs 678 * with the init process. We need to create files with the 679 * umask as defined by the client instead of init's umask. */ 680 if (unshare_fs_struct() < 0) { 681 printk("Unable to start nfsd thread: out of memory\n"); 682 goto out; 683 } 684 685 current->fs->umask = 0; 686 687 /* 688 * thread is spawned with all signals set to SIG_IGN, re-enable 689 * the ones that will bring down the thread 690 */ 691 allow_signal(SIGKILL); 692 allow_signal(SIGHUP); 693 allow_signal(SIGINT); 694 allow_signal(SIGQUIT); 695 696 nfsdstats.th_cnt++; 697 mutex_unlock(&nfsd_mutex); 698 699 set_freezable(); 700 701 /* 702 * The main request loop 703 */ 704 for (;;) { 705 /* Update sv_maxconn if it has changed */ 706 rqstp->rq_server->sv_maxconn = nn->max_connections; 707 708 /* 709 * Find a socket with data available and call its 710 * recvfrom routine. 711 */ 712 while ((err = svc_recv(rqstp, 60*60*HZ)) == -EAGAIN) 713 ; 714 if (err == -EINTR) 715 break; 716 validate_process_creds(); 717 svc_process(rqstp); 718 validate_process_creds(); 719 } 720 721 /* Clear signals before calling svc_exit_thread() */ 722 flush_signals(current); 723 724 mutex_lock(&nfsd_mutex); 725 nfsdstats.th_cnt --; 726 727 out: 728 rqstp->rq_server = NULL; 729 730 /* Release the thread */ 731 svc_exit_thread(rqstp); 732 733 nfsd_destroy(net); 734 735 /* Release module */ 736 mutex_unlock(&nfsd_mutex); 737 module_put_and_exit(0); 738 return 0; 739 } 740 741 static __be32 map_new_errors(u32 vers, __be32 nfserr) 742 { 743 if (nfserr == nfserr_jukebox && vers == 2) 744 return nfserr_dropit; 745 if (nfserr == nfserr_wrongsec && vers < 4) 746 return nfserr_acces; 747 return nfserr; 748 } 749 750 /* 751 * A write procedure can have a large argument, and a read procedure can 752 * have a large reply, but no NFSv2 or NFSv3 procedure has argument and 753 * reply that can both be larger than a page. The xdr code has taken 754 * advantage of this assumption to be a sloppy about bounds checking in 755 * some cases. Pending a rewrite of the NFSv2/v3 xdr code to fix that 756 * problem, we enforce these assumptions here: 757 */ 758 static bool nfs_request_too_big(struct svc_rqst *rqstp, 759 struct svc_procedure *proc) 760 { 761 /* 762 * The ACL code has more careful bounds-checking and is not 763 * susceptible to this problem: 764 */ 765 if (rqstp->rq_prog != NFS_PROGRAM) 766 return false; 767 /* 768 * Ditto NFSv4 (which can in theory have argument and reply both 769 * more than a page): 770 */ 771 if (rqstp->rq_vers >= 4) 772 return false; 773 /* The reply will be small, we're OK: */ 774 if (proc->pc_xdrressize > 0 && 775 proc->pc_xdrressize < XDR_QUADLEN(PAGE_SIZE)) 776 return false; 777 778 return rqstp->rq_arg.len > PAGE_SIZE; 779 } 780 781 int 782 nfsd_dispatch(struct svc_rqst *rqstp, __be32 *statp) 783 { 784 struct svc_procedure *proc; 785 kxdrproc_t xdr; 786 __be32 nfserr; 787 __be32 *nfserrp; 788 789 dprintk("nfsd_dispatch: vers %d proc %d\n", 790 rqstp->rq_vers, rqstp->rq_proc); 791 proc = rqstp->rq_procinfo; 792 793 if (nfs_request_too_big(rqstp, proc)) { 794 dprintk("nfsd: NFSv%d argument too large\n", rqstp->rq_vers); 795 *statp = rpc_garbage_args; 796 return 1; 797 } 798 /* 799 * Give the xdr decoder a chance to change this if it wants 800 * (necessary in the NFSv4.0 compound case) 801 */ 802 rqstp->rq_cachetype = proc->pc_cachetype; 803 /* Decode arguments */ 804 xdr = proc->pc_decode; 805 if (xdr && !xdr(rqstp, (__be32*)rqstp->rq_arg.head[0].iov_base, 806 rqstp->rq_argp)) { 807 dprintk("nfsd: failed to decode arguments!\n"); 808 *statp = rpc_garbage_args; 809 return 1; 810 } 811 812 /* Check whether we have this call in the cache. */ 813 switch (nfsd_cache_lookup(rqstp)) { 814 case RC_DROPIT: 815 return 0; 816 case RC_REPLY: 817 return 1; 818 case RC_DOIT:; 819 /* do it */ 820 } 821 822 /* need to grab the location to store the status, as 823 * nfsv4 does some encoding while processing 824 */ 825 nfserrp = rqstp->rq_res.head[0].iov_base 826 + rqstp->rq_res.head[0].iov_len; 827 rqstp->rq_res.head[0].iov_len += sizeof(__be32); 828 829 /* Now call the procedure handler, and encode NFS status. */ 830 nfserr = proc->pc_func(rqstp, rqstp->rq_argp, rqstp->rq_resp); 831 nfserr = map_new_errors(rqstp->rq_vers, nfserr); 832 if (nfserr == nfserr_dropit || test_bit(RQ_DROPME, &rqstp->rq_flags)) { 833 dprintk("nfsd: Dropping request; may be revisited later\n"); 834 nfsd_cache_update(rqstp, RC_NOCACHE, NULL); 835 return 0; 836 } 837 838 if (rqstp->rq_proc != 0) 839 *nfserrp++ = nfserr; 840 841 /* Encode result. 842 * For NFSv2, additional info is never returned in case of an error. 843 */ 844 if (!(nfserr && rqstp->rq_vers == 2)) { 845 xdr = proc->pc_encode; 846 if (xdr && !xdr(rqstp, nfserrp, 847 rqstp->rq_resp)) { 848 /* Failed to encode result. Release cache entry */ 849 dprintk("nfsd: failed to encode result!\n"); 850 nfsd_cache_update(rqstp, RC_NOCACHE, NULL); 851 *statp = rpc_system_err; 852 return 1; 853 } 854 } 855 856 /* Store reply in cache. */ 857 nfsd_cache_update(rqstp, rqstp->rq_cachetype, statp + 1); 858 return 1; 859 } 860 861 int nfsd_pool_stats_open(struct inode *inode, struct file *file) 862 { 863 int ret; 864 struct nfsd_net *nn = net_generic(inode->i_sb->s_fs_info, nfsd_net_id); 865 866 mutex_lock(&nfsd_mutex); 867 if (nn->nfsd_serv == NULL) { 868 mutex_unlock(&nfsd_mutex); 869 return -ENODEV; 870 } 871 /* bump up the psudo refcount while traversing */ 872 svc_get(nn->nfsd_serv); 873 ret = svc_pool_stats_open(nn->nfsd_serv, file); 874 mutex_unlock(&nfsd_mutex); 875 return ret; 876 } 877 878 int nfsd_pool_stats_release(struct inode *inode, struct file *file) 879 { 880 int ret = seq_release(inode, file); 881 struct net *net = inode->i_sb->s_fs_info; 882 883 mutex_lock(&nfsd_mutex); 884 /* this function really, really should have been called svc_put() */ 885 nfsd_destroy(net); 886 mutex_unlock(&nfsd_mutex); 887 return ret; 888 } 889