1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Central processing for nfsd. 4 * 5 * Authors: Olaf Kirch (okir@monad.swb.de) 6 * 7 * Copyright (C) 1995, 1996, 1997 Olaf Kirch <okir@monad.swb.de> 8 */ 9 10 #include <linux/sched/signal.h> 11 #include <linux/freezer.h> 12 #include <linux/module.h> 13 #include <linux/fs_struct.h> 14 #include <linux/swap.h> 15 16 #include <linux/sunrpc/stats.h> 17 #include <linux/sunrpc/svcsock.h> 18 #include <linux/sunrpc/svc_xprt.h> 19 #include <linux/lockd/bind.h> 20 #include <linux/nfsacl.h> 21 #include <linux/seq_file.h> 22 #include <linux/inetdevice.h> 23 #include <net/addrconf.h> 24 #include <net/ipv6.h> 25 #include <net/net_namespace.h> 26 #include "nfsd.h" 27 #include "cache.h" 28 #include "vfs.h" 29 #include "netns.h" 30 31 #define NFSDDBG_FACILITY NFSDDBG_SVC 32 33 extern struct svc_program nfsd_program; 34 static int nfsd(void *vrqstp); 35 36 /* 37 * nfsd_mutex protects nn->nfsd_serv -- both the pointer itself and the members 38 * of the svc_serv struct. In particular, ->sv_nrthreads but also to some 39 * extent ->sv_temp_socks and ->sv_permsocks. It also protects nfsdstats.th_cnt 40 * 41 * If (out side the lock) nn->nfsd_serv is non-NULL, then it must point to a 42 * properly initialised 'struct svc_serv' with ->sv_nrthreads > 0. That number 43 * of nfsd threads must exist and each must listed in ->sp_all_threads in each 44 * entry of ->sv_pools[]. 45 * 46 * Transitions of the thread count between zero and non-zero are of particular 47 * interest since the svc_serv needs to be created and initialized at that 48 * point, or freed. 49 * 50 * Finally, the nfsd_mutex also protects some of the global variables that are 51 * accessed when nfsd starts and that are settable via the write_* routines in 52 * nfsctl.c. In particular: 53 * 54 * user_recovery_dirname 55 * user_lease_time 56 * nfsd_versions 57 */ 58 DEFINE_MUTEX(nfsd_mutex); 59 60 /* 61 * nfsd_drc_lock protects nfsd_drc_max_pages and nfsd_drc_pages_used. 62 * nfsd_drc_max_pages limits the total amount of memory available for 63 * version 4.1 DRC caches. 64 * nfsd_drc_pages_used tracks the current version 4.1 DRC memory usage. 65 */ 66 spinlock_t nfsd_drc_lock; 67 unsigned long nfsd_drc_max_mem; 68 unsigned long nfsd_drc_mem_used; 69 70 #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL) 71 static struct svc_stat nfsd_acl_svcstats; 72 static const 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 const 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 const 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 const 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 static bool nfsd_supported_minorversions[NFSD_SUPPORTED_MINOR_VERSION + 1] = { 125 [0] = 1, 126 [1] = 1, 127 [2] = 1, 128 }; 129 130 int nfsd_vers(int vers, enum vers_op change) 131 { 132 if (vers < NFSD_MINVERS || vers >= NFSD_NRVERS) 133 return 0; 134 switch(change) { 135 case NFSD_SET: 136 nfsd_versions[vers] = nfsd_version[vers]; 137 #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL) 138 if (vers < NFSD_ACL_NRVERS) 139 nfsd_acl_versions[vers] = nfsd_acl_version[vers]; 140 #endif 141 break; 142 case NFSD_CLEAR: 143 nfsd_versions[vers] = NULL; 144 #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL) 145 if (vers < NFSD_ACL_NRVERS) 146 nfsd_acl_versions[vers] = NULL; 147 #endif 148 break; 149 case NFSD_TEST: 150 return nfsd_versions[vers] != NULL; 151 case NFSD_AVAIL: 152 return nfsd_version[vers] != NULL; 153 } 154 return 0; 155 } 156 157 static void 158 nfsd_adjust_nfsd_versions4(void) 159 { 160 unsigned i; 161 162 for (i = 0; i <= NFSD_SUPPORTED_MINOR_VERSION; i++) { 163 if (nfsd_supported_minorversions[i]) 164 return; 165 } 166 nfsd_vers(4, NFSD_CLEAR); 167 } 168 169 int nfsd_minorversion(u32 minorversion, enum vers_op change) 170 { 171 if (minorversion > NFSD_SUPPORTED_MINOR_VERSION && 172 change != NFSD_AVAIL) 173 return -1; 174 switch(change) { 175 case NFSD_SET: 176 nfsd_supported_minorversions[minorversion] = true; 177 nfsd_vers(4, NFSD_SET); 178 break; 179 case NFSD_CLEAR: 180 nfsd_supported_minorversions[minorversion] = false; 181 nfsd_adjust_nfsd_versions4(); 182 break; 183 case NFSD_TEST: 184 return nfsd_supported_minorversions[minorversion]; 185 case NFSD_AVAIL: 186 return minorversion <= NFSD_SUPPORTED_MINOR_VERSION; 187 } 188 return 0; 189 } 190 191 /* 192 * Maximum number of nfsd processes 193 */ 194 #define NFSD_MAXSERVS 8192 195 196 int nfsd_nrthreads(struct net *net) 197 { 198 int rv = 0; 199 struct nfsd_net *nn = net_generic(net, nfsd_net_id); 200 201 mutex_lock(&nfsd_mutex); 202 if (nn->nfsd_serv) 203 rv = nn->nfsd_serv->sv_nrthreads; 204 mutex_unlock(&nfsd_mutex); 205 return rv; 206 } 207 208 static int nfsd_init_socks(struct net *net) 209 { 210 int error; 211 struct nfsd_net *nn = net_generic(net, nfsd_net_id); 212 213 if (!list_empty(&nn->nfsd_serv->sv_permsocks)) 214 return 0; 215 216 error = svc_create_xprt(nn->nfsd_serv, "udp", net, PF_INET, NFS_PORT, 217 SVC_SOCK_DEFAULTS); 218 if (error < 0) 219 return error; 220 221 error = svc_create_xprt(nn->nfsd_serv, "tcp", net, PF_INET, NFS_PORT, 222 SVC_SOCK_DEFAULTS); 223 if (error < 0) 224 return error; 225 226 return 0; 227 } 228 229 static int nfsd_users = 0; 230 231 static int nfsd_startup_generic(int nrservs) 232 { 233 int ret; 234 235 if (nfsd_users++) 236 return 0; 237 238 /* 239 * Readahead param cache - will no-op if it already exists. 240 * (Note therefore results will be suboptimal if number of 241 * threads is modified after nfsd start.) 242 */ 243 ret = nfsd_racache_init(2*nrservs); 244 if (ret) 245 goto dec_users; 246 247 ret = nfs4_state_start(); 248 if (ret) 249 goto out_racache; 250 return 0; 251 252 out_racache: 253 nfsd_racache_shutdown(); 254 dec_users: 255 nfsd_users--; 256 return ret; 257 } 258 259 static void nfsd_shutdown_generic(void) 260 { 261 if (--nfsd_users) 262 return; 263 264 nfs4_state_shutdown(); 265 nfsd_racache_shutdown(); 266 } 267 268 static bool nfsd_needs_lockd(void) 269 { 270 #if defined(CONFIG_NFSD_V3) 271 return (nfsd_versions[2] != NULL) || (nfsd_versions[3] != NULL); 272 #else 273 return (nfsd_versions[2] != NULL); 274 #endif 275 } 276 277 static int nfsd_startup_net(int nrservs, struct net *net) 278 { 279 struct nfsd_net *nn = net_generic(net, nfsd_net_id); 280 int ret; 281 282 if (nn->nfsd_net_up) 283 return 0; 284 285 ret = nfsd_startup_generic(nrservs); 286 if (ret) 287 return ret; 288 ret = nfsd_init_socks(net); 289 if (ret) 290 goto out_socks; 291 292 if (nfsd_needs_lockd() && !nn->lockd_up) { 293 ret = lockd_up(net); 294 if (ret) 295 goto out_socks; 296 nn->lockd_up = 1; 297 } 298 299 ret = nfs4_state_start_net(net); 300 if (ret) 301 goto out_lockd; 302 303 nn->nfsd_net_up = true; 304 return 0; 305 306 out_lockd: 307 if (nn->lockd_up) { 308 lockd_down(net); 309 nn->lockd_up = 0; 310 } 311 out_socks: 312 nfsd_shutdown_generic(); 313 return ret; 314 } 315 316 static void nfsd_shutdown_net(struct net *net) 317 { 318 struct nfsd_net *nn = net_generic(net, nfsd_net_id); 319 320 nfs4_state_shutdown_net(net); 321 if (nn->lockd_up) { 322 lockd_down(net); 323 nn->lockd_up = 0; 324 } 325 nn->nfsd_net_up = false; 326 nfsd_shutdown_generic(); 327 } 328 329 static int nfsd_inetaddr_event(struct notifier_block *this, unsigned long event, 330 void *ptr) 331 { 332 struct in_ifaddr *ifa = (struct in_ifaddr *)ptr; 333 struct net_device *dev = ifa->ifa_dev->dev; 334 struct net *net = dev_net(dev); 335 struct nfsd_net *nn = net_generic(net, nfsd_net_id); 336 struct sockaddr_in sin; 337 338 if ((event != NETDEV_DOWN) || 339 !atomic_inc_not_zero(&nn->ntf_refcnt)) 340 goto out; 341 342 if (nn->nfsd_serv) { 343 dprintk("nfsd_inetaddr_event: removed %pI4\n", &ifa->ifa_local); 344 sin.sin_family = AF_INET; 345 sin.sin_addr.s_addr = ifa->ifa_local; 346 svc_age_temp_xprts_now(nn->nfsd_serv, (struct sockaddr *)&sin); 347 } 348 atomic_dec(&nn->ntf_refcnt); 349 wake_up(&nn->ntf_wq); 350 351 out: 352 return NOTIFY_DONE; 353 } 354 355 static struct notifier_block nfsd_inetaddr_notifier = { 356 .notifier_call = nfsd_inetaddr_event, 357 }; 358 359 #if IS_ENABLED(CONFIG_IPV6) 360 static int nfsd_inet6addr_event(struct notifier_block *this, 361 unsigned long event, void *ptr) 362 { 363 struct inet6_ifaddr *ifa = (struct inet6_ifaddr *)ptr; 364 struct net_device *dev = ifa->idev->dev; 365 struct net *net = dev_net(dev); 366 struct nfsd_net *nn = net_generic(net, nfsd_net_id); 367 struct sockaddr_in6 sin6; 368 369 if ((event != NETDEV_DOWN) || 370 !atomic_inc_not_zero(&nn->ntf_refcnt)) 371 goto out; 372 373 if (nn->nfsd_serv) { 374 dprintk("nfsd_inet6addr_event: removed %pI6\n", &ifa->addr); 375 sin6.sin6_family = AF_INET6; 376 sin6.sin6_addr = ifa->addr; 377 if (ipv6_addr_type(&sin6.sin6_addr) & IPV6_ADDR_LINKLOCAL) 378 sin6.sin6_scope_id = ifa->idev->dev->ifindex; 379 svc_age_temp_xprts_now(nn->nfsd_serv, (struct sockaddr *)&sin6); 380 } 381 atomic_dec(&nn->ntf_refcnt); 382 wake_up(&nn->ntf_wq); 383 out: 384 return NOTIFY_DONE; 385 } 386 387 static struct notifier_block nfsd_inet6addr_notifier = { 388 .notifier_call = nfsd_inet6addr_event, 389 }; 390 #endif 391 392 /* Only used under nfsd_mutex, so this atomic may be overkill: */ 393 static atomic_t nfsd_notifier_refcount = ATOMIC_INIT(0); 394 395 static void nfsd_last_thread(struct svc_serv *serv, struct net *net) 396 { 397 struct nfsd_net *nn = net_generic(net, nfsd_net_id); 398 399 atomic_dec(&nn->ntf_refcnt); 400 /* check if the notifier still has clients */ 401 if (atomic_dec_return(&nfsd_notifier_refcount) == 0) { 402 unregister_inetaddr_notifier(&nfsd_inetaddr_notifier); 403 #if IS_ENABLED(CONFIG_IPV6) 404 unregister_inet6addr_notifier(&nfsd_inet6addr_notifier); 405 #endif 406 } 407 wait_event(nn->ntf_wq, atomic_read(&nn->ntf_refcnt) == 0); 408 409 /* 410 * write_ports can create the server without actually starting 411 * any threads--if we get shut down before any threads are 412 * started, then nfsd_last_thread will be run before any of this 413 * other initialization has been done except the rpcb information. 414 */ 415 svc_rpcb_cleanup(serv, net); 416 if (!nn->nfsd_net_up) 417 return; 418 419 nfsd_shutdown_net(net); 420 printk(KERN_WARNING "nfsd: last server has exited, flushing export " 421 "cache\n"); 422 nfsd_export_flush(net); 423 } 424 425 void nfsd_reset_versions(void) 426 { 427 int i; 428 429 for (i = 0; i < NFSD_NRVERS; i++) 430 if (nfsd_vers(i, NFSD_TEST)) 431 return; 432 433 for (i = 0; i < NFSD_NRVERS; i++) 434 if (i != 4) 435 nfsd_vers(i, NFSD_SET); 436 else { 437 int minor = 0; 438 while (nfsd_minorversion(minor, NFSD_SET) >= 0) 439 minor++; 440 } 441 } 442 443 /* 444 * Each session guarantees a negotiated per slot memory cache for replies 445 * which in turn consumes memory beyond the v2/v3/v4.0 server. A dedicated 446 * NFSv4.1 server might want to use more memory for a DRC than a machine 447 * with mutiple services. 448 * 449 * Impose a hard limit on the number of pages for the DRC which varies 450 * according to the machines free pages. This is of course only a default. 451 * 452 * For now this is a #defined shift which could be under admin control 453 * in the future. 454 */ 455 static void set_max_drc(void) 456 { 457 #define NFSD_DRC_SIZE_SHIFT 7 458 nfsd_drc_max_mem = (nr_free_buffer_pages() 459 >> NFSD_DRC_SIZE_SHIFT) * PAGE_SIZE; 460 nfsd_drc_mem_used = 0; 461 spin_lock_init(&nfsd_drc_lock); 462 dprintk("%s nfsd_drc_max_mem %lu \n", __func__, nfsd_drc_max_mem); 463 } 464 465 static int nfsd_get_default_max_blksize(void) 466 { 467 struct sysinfo i; 468 unsigned long long target; 469 unsigned long ret; 470 471 si_meminfo(&i); 472 target = (i.totalram - i.totalhigh) << PAGE_SHIFT; 473 /* 474 * Aim for 1/4096 of memory per thread This gives 1MB on 4Gig 475 * machines, but only uses 32K on 128M machines. Bottom out at 476 * 8K on 32M and smaller. Of course, this is only a default. 477 */ 478 target >>= 12; 479 480 ret = NFSSVC_MAXBLKSIZE; 481 while (ret > target && ret >= 8*1024*2) 482 ret /= 2; 483 return ret; 484 } 485 486 static const struct svc_serv_ops nfsd_thread_sv_ops = { 487 .svo_shutdown = nfsd_last_thread, 488 .svo_function = nfsd, 489 .svo_enqueue_xprt = svc_xprt_do_enqueue, 490 .svo_setup = svc_set_num_threads, 491 .svo_module = THIS_MODULE, 492 }; 493 494 int nfsd_create_serv(struct net *net) 495 { 496 int error; 497 struct nfsd_net *nn = net_generic(net, nfsd_net_id); 498 499 WARN_ON(!mutex_is_locked(&nfsd_mutex)); 500 if (nn->nfsd_serv) { 501 svc_get(nn->nfsd_serv); 502 return 0; 503 } 504 if (nfsd_max_blksize == 0) 505 nfsd_max_blksize = nfsd_get_default_max_blksize(); 506 nfsd_reset_versions(); 507 nn->nfsd_serv = svc_create_pooled(&nfsd_program, nfsd_max_blksize, 508 &nfsd_thread_sv_ops); 509 if (nn->nfsd_serv == NULL) 510 return -ENOMEM; 511 512 nn->nfsd_serv->sv_maxconn = nn->max_connections; 513 error = svc_bind(nn->nfsd_serv, net); 514 if (error < 0) { 515 svc_destroy(nn->nfsd_serv); 516 return error; 517 } 518 519 set_max_drc(); 520 /* check if the notifier is already set */ 521 if (atomic_inc_return(&nfsd_notifier_refcount) == 1) { 522 register_inetaddr_notifier(&nfsd_inetaddr_notifier); 523 #if IS_ENABLED(CONFIG_IPV6) 524 register_inet6addr_notifier(&nfsd_inet6addr_notifier); 525 #endif 526 } 527 atomic_inc(&nn->ntf_refcnt); 528 ktime_get_real_ts64(&nn->nfssvc_boot); /* record boot time */ 529 return 0; 530 } 531 532 int nfsd_nrpools(struct net *net) 533 { 534 struct nfsd_net *nn = net_generic(net, nfsd_net_id); 535 536 if (nn->nfsd_serv == NULL) 537 return 0; 538 else 539 return nn->nfsd_serv->sv_nrpools; 540 } 541 542 int nfsd_get_nrthreads(int n, int *nthreads, struct net *net) 543 { 544 int i = 0; 545 struct nfsd_net *nn = net_generic(net, nfsd_net_id); 546 547 if (nn->nfsd_serv != NULL) { 548 for (i = 0; i < nn->nfsd_serv->sv_nrpools && i < n; i++) 549 nthreads[i] = nn->nfsd_serv->sv_pools[i].sp_nrthreads; 550 } 551 552 return 0; 553 } 554 555 void nfsd_destroy(struct net *net) 556 { 557 struct nfsd_net *nn = net_generic(net, nfsd_net_id); 558 int destroy = (nn->nfsd_serv->sv_nrthreads == 1); 559 560 if (destroy) 561 svc_shutdown_net(nn->nfsd_serv, net); 562 svc_destroy(nn->nfsd_serv); 563 if (destroy) 564 nn->nfsd_serv = NULL; 565 } 566 567 int nfsd_set_nrthreads(int n, int *nthreads, struct net *net) 568 { 569 int i = 0; 570 int tot = 0; 571 int err = 0; 572 struct nfsd_net *nn = net_generic(net, nfsd_net_id); 573 574 WARN_ON(!mutex_is_locked(&nfsd_mutex)); 575 576 if (nn->nfsd_serv == NULL || n <= 0) 577 return 0; 578 579 if (n > nn->nfsd_serv->sv_nrpools) 580 n = nn->nfsd_serv->sv_nrpools; 581 582 /* enforce a global maximum number of threads */ 583 tot = 0; 584 for (i = 0; i < n; i++) { 585 nthreads[i] = min(nthreads[i], NFSD_MAXSERVS); 586 tot += nthreads[i]; 587 } 588 if (tot > NFSD_MAXSERVS) { 589 /* total too large: scale down requested numbers */ 590 for (i = 0; i < n && tot > 0; i++) { 591 int new = nthreads[i] * NFSD_MAXSERVS / tot; 592 tot -= (nthreads[i] - new); 593 nthreads[i] = new; 594 } 595 for (i = 0; i < n && tot > 0; i++) { 596 nthreads[i]--; 597 tot--; 598 } 599 } 600 601 /* 602 * There must always be a thread in pool 0; the admin 603 * can't shut down NFS completely using pool_threads. 604 */ 605 if (nthreads[0] == 0) 606 nthreads[0] = 1; 607 608 /* apply the new numbers */ 609 svc_get(nn->nfsd_serv); 610 for (i = 0; i < n; i++) { 611 err = nn->nfsd_serv->sv_ops->svo_setup(nn->nfsd_serv, 612 &nn->nfsd_serv->sv_pools[i], nthreads[i]); 613 if (err) 614 break; 615 } 616 nfsd_destroy(net); 617 return err; 618 } 619 620 /* 621 * Adjust the number of threads and return the new number of threads. 622 * This is also the function that starts the server if necessary, if 623 * this is the first time nrservs is nonzero. 624 */ 625 int 626 nfsd_svc(int nrservs, struct net *net) 627 { 628 int error; 629 bool nfsd_up_before; 630 struct nfsd_net *nn = net_generic(net, nfsd_net_id); 631 632 mutex_lock(&nfsd_mutex); 633 dprintk("nfsd: creating service\n"); 634 635 nrservs = max(nrservs, 0); 636 nrservs = min(nrservs, NFSD_MAXSERVS); 637 error = 0; 638 639 if (nrservs == 0 && nn->nfsd_serv == NULL) 640 goto out; 641 642 error = nfsd_create_serv(net); 643 if (error) 644 goto out; 645 646 nfsd_up_before = nn->nfsd_net_up; 647 648 error = nfsd_startup_net(nrservs, net); 649 if (error) 650 goto out_destroy; 651 error = nn->nfsd_serv->sv_ops->svo_setup(nn->nfsd_serv, 652 NULL, nrservs); 653 if (error) 654 goto out_shutdown; 655 /* We are holding a reference to nn->nfsd_serv which 656 * we don't want to count in the return value, 657 * so subtract 1 658 */ 659 error = nn->nfsd_serv->sv_nrthreads - 1; 660 out_shutdown: 661 if (error < 0 && !nfsd_up_before) 662 nfsd_shutdown_net(net); 663 out_destroy: 664 nfsd_destroy(net); /* Release server */ 665 out: 666 mutex_unlock(&nfsd_mutex); 667 return error; 668 } 669 670 671 /* 672 * This is the NFS server kernel thread 673 */ 674 static int 675 nfsd(void *vrqstp) 676 { 677 struct svc_rqst *rqstp = (struct svc_rqst *) vrqstp; 678 struct svc_xprt *perm_sock = list_entry(rqstp->rq_server->sv_permsocks.next, typeof(struct svc_xprt), xpt_list); 679 struct net *net = perm_sock->xpt_net; 680 struct nfsd_net *nn = net_generic(net, nfsd_net_id); 681 int err; 682 683 /* Lock module and set up kernel thread */ 684 mutex_lock(&nfsd_mutex); 685 686 /* At this point, the thread shares current->fs 687 * with the init process. We need to create files with the 688 * umask as defined by the client instead of init's umask. */ 689 if (unshare_fs_struct() < 0) { 690 printk("Unable to start nfsd thread: out of memory\n"); 691 goto out; 692 } 693 694 current->fs->umask = 0; 695 696 /* 697 * thread is spawned with all signals set to SIG_IGN, re-enable 698 * the ones that will bring down the thread 699 */ 700 allow_signal(SIGKILL); 701 allow_signal(SIGHUP); 702 allow_signal(SIGINT); 703 allow_signal(SIGQUIT); 704 705 nfsdstats.th_cnt++; 706 mutex_unlock(&nfsd_mutex); 707 708 set_freezable(); 709 710 /* 711 * The main request loop 712 */ 713 for (;;) { 714 /* Update sv_maxconn if it has changed */ 715 rqstp->rq_server->sv_maxconn = nn->max_connections; 716 717 /* 718 * Find a socket with data available and call its 719 * recvfrom routine. 720 */ 721 while ((err = svc_recv(rqstp, 60*60*HZ)) == -EAGAIN) 722 ; 723 if (err == -EINTR) 724 break; 725 validate_process_creds(); 726 svc_process(rqstp); 727 validate_process_creds(); 728 } 729 730 /* Clear signals before calling svc_exit_thread() */ 731 flush_signals(current); 732 733 mutex_lock(&nfsd_mutex); 734 nfsdstats.th_cnt --; 735 736 out: 737 rqstp->rq_server = NULL; 738 739 /* Release the thread */ 740 svc_exit_thread(rqstp); 741 742 nfsd_destroy(net); 743 744 /* Release module */ 745 mutex_unlock(&nfsd_mutex); 746 module_put_and_exit(0); 747 return 0; 748 } 749 750 static __be32 map_new_errors(u32 vers, __be32 nfserr) 751 { 752 if (nfserr == nfserr_jukebox && vers == 2) 753 return nfserr_dropit; 754 if (nfserr == nfserr_wrongsec && vers < 4) 755 return nfserr_acces; 756 return nfserr; 757 } 758 759 /* 760 * A write procedure can have a large argument, and a read procedure can 761 * have a large reply, but no NFSv2 or NFSv3 procedure has argument and 762 * reply that can both be larger than a page. The xdr code has taken 763 * advantage of this assumption to be a sloppy about bounds checking in 764 * some cases. Pending a rewrite of the NFSv2/v3 xdr code to fix that 765 * problem, we enforce these assumptions here: 766 */ 767 static bool nfs_request_too_big(struct svc_rqst *rqstp, 768 const struct svc_procedure *proc) 769 { 770 /* 771 * The ACL code has more careful bounds-checking and is not 772 * susceptible to this problem: 773 */ 774 if (rqstp->rq_prog != NFS_PROGRAM) 775 return false; 776 /* 777 * Ditto NFSv4 (which can in theory have argument and reply both 778 * more than a page): 779 */ 780 if (rqstp->rq_vers >= 4) 781 return false; 782 /* The reply will be small, we're OK: */ 783 if (proc->pc_xdrressize > 0 && 784 proc->pc_xdrressize < XDR_QUADLEN(PAGE_SIZE)) 785 return false; 786 787 return rqstp->rq_arg.len > PAGE_SIZE; 788 } 789 790 int 791 nfsd_dispatch(struct svc_rqst *rqstp, __be32 *statp) 792 { 793 const struct svc_procedure *proc; 794 __be32 nfserr; 795 __be32 *nfserrp; 796 797 dprintk("nfsd_dispatch: vers %d proc %d\n", 798 rqstp->rq_vers, rqstp->rq_proc); 799 proc = rqstp->rq_procinfo; 800 801 if (nfs_request_too_big(rqstp, proc)) { 802 dprintk("nfsd: NFSv%d argument too large\n", rqstp->rq_vers); 803 *statp = rpc_garbage_args; 804 return 1; 805 } 806 /* 807 * Give the xdr decoder a chance to change this if it wants 808 * (necessary in the NFSv4.0 compound case) 809 */ 810 rqstp->rq_cachetype = proc->pc_cachetype; 811 /* Decode arguments */ 812 if (proc->pc_decode && 813 !proc->pc_decode(rqstp, (__be32*)rqstp->rq_arg.head[0].iov_base)) { 814 dprintk("nfsd: failed to decode arguments!\n"); 815 *statp = rpc_garbage_args; 816 return 1; 817 } 818 819 /* Check whether we have this call in the cache. */ 820 switch (nfsd_cache_lookup(rqstp)) { 821 case RC_DROPIT: 822 return 0; 823 case RC_REPLY: 824 return 1; 825 case RC_DOIT:; 826 /* do it */ 827 } 828 829 /* need to grab the location to store the status, as 830 * nfsv4 does some encoding while processing 831 */ 832 nfserrp = rqstp->rq_res.head[0].iov_base 833 + rqstp->rq_res.head[0].iov_len; 834 rqstp->rq_res.head[0].iov_len += sizeof(__be32); 835 836 /* Now call the procedure handler, and encode NFS status. */ 837 nfserr = proc->pc_func(rqstp); 838 nfserr = map_new_errors(rqstp->rq_vers, nfserr); 839 if (nfserr == nfserr_dropit || test_bit(RQ_DROPME, &rqstp->rq_flags)) { 840 dprintk("nfsd: Dropping request; may be revisited later\n"); 841 nfsd_cache_update(rqstp, RC_NOCACHE, NULL); 842 return 0; 843 } 844 845 if (rqstp->rq_proc != 0) 846 *nfserrp++ = nfserr; 847 848 /* Encode result. 849 * For NFSv2, additional info is never returned in case of an error. 850 */ 851 if (!(nfserr && rqstp->rq_vers == 2)) { 852 if (proc->pc_encode && !proc->pc_encode(rqstp, nfserrp)) { 853 /* Failed to encode result. Release cache entry */ 854 dprintk("nfsd: failed to encode result!\n"); 855 nfsd_cache_update(rqstp, RC_NOCACHE, NULL); 856 *statp = rpc_system_err; 857 return 1; 858 } 859 } 860 861 /* Store reply in cache. */ 862 nfsd_cache_update(rqstp, rqstp->rq_cachetype, statp + 1); 863 return 1; 864 } 865 866 int nfsd_pool_stats_open(struct inode *inode, struct file *file) 867 { 868 int ret; 869 struct nfsd_net *nn = net_generic(inode->i_sb->s_fs_info, nfsd_net_id); 870 871 mutex_lock(&nfsd_mutex); 872 if (nn->nfsd_serv == NULL) { 873 mutex_unlock(&nfsd_mutex); 874 return -ENODEV; 875 } 876 /* bump up the psudo refcount while traversing */ 877 svc_get(nn->nfsd_serv); 878 ret = svc_pool_stats_open(nn->nfsd_serv, file); 879 mutex_unlock(&nfsd_mutex); 880 return ret; 881 } 882 883 int nfsd_pool_stats_release(struct inode *inode, struct file *file) 884 { 885 int ret = seq_release(inode, file); 886 struct net *net = inode->i_sb->s_fs_info; 887 888 mutex_lock(&nfsd_mutex); 889 /* this function really, really should have been called svc_put() */ 890 nfsd_destroy(net); 891 mutex_unlock(&nfsd_mutex); 892 return ret; 893 } 894