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.h> 10 #include <linux/freezer.h> 11 #include <linux/fs_struct.h> 12 #include <linux/swap.h> 13 14 #include <linux/sunrpc/stats.h> 15 #include <linux/sunrpc/svcsock.h> 16 #include <linux/lockd/bind.h> 17 #include <linux/nfsacl.h> 18 #include <linux/seq_file.h> 19 #include <net/net_namespace.h> 20 #include "nfsd.h" 21 #include "cache.h" 22 #include "vfs.h" 23 24 #define NFSDDBG_FACILITY NFSDDBG_SVC 25 26 extern struct svc_program nfsd_program; 27 static int nfsd(void *vrqstp); 28 struct timeval nfssvc_boot; 29 30 /* 31 * nfsd_mutex protects nfsd_serv -- both the pointer itself and the members 32 * of the svc_serv struct. In particular, ->sv_nrthreads but also to some 33 * extent ->sv_temp_socks and ->sv_permsocks. It also protects nfsdstats.th_cnt 34 * 35 * If (out side the lock) nfsd_serv is non-NULL, then it must point to a 36 * properly initialised 'struct svc_serv' with ->sv_nrthreads > 0. That number 37 * of nfsd threads must exist and each must listed in ->sp_all_threads in each 38 * entry of ->sv_pools[]. 39 * 40 * Transitions of the thread count between zero and non-zero are of particular 41 * interest since the svc_serv needs to be created and initialized at that 42 * point, or freed. 43 * 44 * Finally, the nfsd_mutex also protects some of the global variables that are 45 * accessed when nfsd starts and that are settable via the write_* routines in 46 * nfsctl.c. In particular: 47 * 48 * user_recovery_dirname 49 * user_lease_time 50 * nfsd_versions 51 */ 52 DEFINE_MUTEX(nfsd_mutex); 53 struct svc_serv *nfsd_serv; 54 55 /* 56 * nfsd_drc_lock protects nfsd_drc_max_pages and nfsd_drc_pages_used. 57 * nfsd_drc_max_pages limits the total amount of memory available for 58 * version 4.1 DRC caches. 59 * nfsd_drc_pages_used tracks the current version 4.1 DRC memory usage. 60 */ 61 spinlock_t nfsd_drc_lock; 62 unsigned int nfsd_drc_max_mem; 63 unsigned int nfsd_drc_mem_used; 64 65 #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL) 66 static struct svc_stat nfsd_acl_svcstats; 67 static struct svc_version * nfsd_acl_version[] = { 68 [2] = &nfsd_acl_version2, 69 [3] = &nfsd_acl_version3, 70 }; 71 72 #define NFSD_ACL_MINVERS 2 73 #define NFSD_ACL_NRVERS ARRAY_SIZE(nfsd_acl_version) 74 static struct svc_version *nfsd_acl_versions[NFSD_ACL_NRVERS]; 75 76 static struct svc_program nfsd_acl_program = { 77 .pg_prog = NFS_ACL_PROGRAM, 78 .pg_nvers = NFSD_ACL_NRVERS, 79 .pg_vers = nfsd_acl_versions, 80 .pg_name = "nfsacl", 81 .pg_class = "nfsd", 82 .pg_stats = &nfsd_acl_svcstats, 83 .pg_authenticate = &svc_set_client, 84 }; 85 86 static struct svc_stat nfsd_acl_svcstats = { 87 .program = &nfsd_acl_program, 88 }; 89 #endif /* defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL) */ 90 91 static struct svc_version * nfsd_version[] = { 92 [2] = &nfsd_version2, 93 #if defined(CONFIG_NFSD_V3) 94 [3] = &nfsd_version3, 95 #endif 96 #if defined(CONFIG_NFSD_V4) 97 [4] = &nfsd_version4, 98 #endif 99 }; 100 101 #define NFSD_MINVERS 2 102 #define NFSD_NRVERS ARRAY_SIZE(nfsd_version) 103 static struct svc_version *nfsd_versions[NFSD_NRVERS]; 104 105 struct svc_program nfsd_program = { 106 #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL) 107 .pg_next = &nfsd_acl_program, 108 #endif 109 .pg_prog = NFS_PROGRAM, /* program number */ 110 .pg_nvers = NFSD_NRVERS, /* nr of entries in nfsd_version */ 111 .pg_vers = nfsd_versions, /* version table */ 112 .pg_name = "nfsd", /* program name */ 113 .pg_class = "nfsd", /* authentication class */ 114 .pg_stats = &nfsd_svcstats, /* version table */ 115 .pg_authenticate = &svc_set_client, /* export authentication */ 116 117 }; 118 119 u32 nfsd_supported_minorversion; 120 121 int nfsd_vers(int vers, enum vers_op change) 122 { 123 if (vers < NFSD_MINVERS || vers >= NFSD_NRVERS) 124 return 0; 125 switch(change) { 126 case NFSD_SET: 127 nfsd_versions[vers] = nfsd_version[vers]; 128 #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL) 129 if (vers < NFSD_ACL_NRVERS) 130 nfsd_acl_versions[vers] = nfsd_acl_version[vers]; 131 #endif 132 break; 133 case NFSD_CLEAR: 134 nfsd_versions[vers] = NULL; 135 #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL) 136 if (vers < NFSD_ACL_NRVERS) 137 nfsd_acl_versions[vers] = NULL; 138 #endif 139 break; 140 case NFSD_TEST: 141 return nfsd_versions[vers] != NULL; 142 case NFSD_AVAIL: 143 return nfsd_version[vers] != NULL; 144 } 145 return 0; 146 } 147 148 int nfsd_minorversion(u32 minorversion, enum vers_op change) 149 { 150 if (minorversion > NFSD_SUPPORTED_MINOR_VERSION) 151 return -1; 152 switch(change) { 153 case NFSD_SET: 154 nfsd_supported_minorversion = minorversion; 155 break; 156 case NFSD_CLEAR: 157 if (minorversion == 0) 158 return -1; 159 nfsd_supported_minorversion = minorversion - 1; 160 break; 161 case NFSD_TEST: 162 return minorversion <= nfsd_supported_minorversion; 163 case NFSD_AVAIL: 164 return minorversion <= NFSD_SUPPORTED_MINOR_VERSION; 165 } 166 return 0; 167 } 168 169 /* 170 * Maximum number of nfsd processes 171 */ 172 #define NFSD_MAXSERVS 8192 173 174 int nfsd_nrthreads(void) 175 { 176 int rv = 0; 177 mutex_lock(&nfsd_mutex); 178 if (nfsd_serv) 179 rv = nfsd_serv->sv_nrthreads; 180 mutex_unlock(&nfsd_mutex); 181 return rv; 182 } 183 184 static int nfsd_init_socks(int port) 185 { 186 int error; 187 if (!list_empty(&nfsd_serv->sv_permsocks)) 188 return 0; 189 190 error = svc_create_xprt(nfsd_serv, "udp", &init_net, PF_INET, port, 191 SVC_SOCK_DEFAULTS); 192 if (error < 0) 193 return error; 194 195 error = svc_create_xprt(nfsd_serv, "tcp", &init_net, PF_INET, port, 196 SVC_SOCK_DEFAULTS); 197 if (error < 0) 198 return error; 199 200 return 0; 201 } 202 203 static bool nfsd_up = false; 204 205 static int nfsd_startup(unsigned short port, int nrservs) 206 { 207 int ret; 208 209 if (nfsd_up) 210 return 0; 211 /* 212 * Readahead param cache - will no-op if it already exists. 213 * (Note therefore results will be suboptimal if number of 214 * threads is modified after nfsd start.) 215 */ 216 ret = nfsd_racache_init(2*nrservs); 217 if (ret) 218 return ret; 219 ret = nfsd_init_socks(port); 220 if (ret) 221 goto out_racache; 222 ret = lockd_up(); 223 if (ret) 224 goto out_racache; 225 ret = nfs4_state_start(); 226 if (ret) 227 goto out_lockd; 228 nfsd_up = true; 229 return 0; 230 out_lockd: 231 lockd_down(); 232 out_racache: 233 nfsd_racache_shutdown(); 234 return ret; 235 } 236 237 static void nfsd_shutdown(void) 238 { 239 /* 240 * write_ports can create the server without actually starting 241 * any threads--if we get shut down before any threads are 242 * started, then nfsd_last_thread will be run before any of this 243 * other initialization has been done. 244 */ 245 if (!nfsd_up) 246 return; 247 nfs4_state_shutdown(); 248 lockd_down(); 249 nfsd_racache_shutdown(); 250 nfsd_up = false; 251 } 252 253 static void nfsd_last_thread(struct svc_serv *serv) 254 { 255 /* When last nfsd thread exits we need to do some clean-up */ 256 nfsd_serv = NULL; 257 nfsd_shutdown(); 258 259 printk(KERN_WARNING "nfsd: last server has exited, flushing export " 260 "cache\n"); 261 nfsd_export_flush(); 262 } 263 264 void nfsd_reset_versions(void) 265 { 266 int found_one = 0; 267 int i; 268 269 for (i = NFSD_MINVERS; i < NFSD_NRVERS; i++) { 270 if (nfsd_program.pg_vers[i]) 271 found_one = 1; 272 } 273 274 if (!found_one) { 275 for (i = NFSD_MINVERS; i < NFSD_NRVERS; i++) 276 nfsd_program.pg_vers[i] = nfsd_version[i]; 277 #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL) 278 for (i = NFSD_ACL_MINVERS; i < NFSD_ACL_NRVERS; i++) 279 nfsd_acl_program.pg_vers[i] = 280 nfsd_acl_version[i]; 281 #endif 282 } 283 } 284 285 /* 286 * Each session guarantees a negotiated per slot memory cache for replies 287 * which in turn consumes memory beyond the v2/v3/v4.0 server. A dedicated 288 * NFSv4.1 server might want to use more memory for a DRC than a machine 289 * with mutiple services. 290 * 291 * Impose a hard limit on the number of pages for the DRC which varies 292 * according to the machines free pages. This is of course only a default. 293 * 294 * For now this is a #defined shift which could be under admin control 295 * in the future. 296 */ 297 static void set_max_drc(void) 298 { 299 #define NFSD_DRC_SIZE_SHIFT 10 300 nfsd_drc_max_mem = (nr_free_buffer_pages() 301 >> NFSD_DRC_SIZE_SHIFT) * PAGE_SIZE; 302 nfsd_drc_mem_used = 0; 303 spin_lock_init(&nfsd_drc_lock); 304 dprintk("%s nfsd_drc_max_mem %u \n", __func__, nfsd_drc_max_mem); 305 } 306 307 int nfsd_create_serv(void) 308 { 309 int err = 0; 310 311 WARN_ON(!mutex_is_locked(&nfsd_mutex)); 312 if (nfsd_serv) { 313 svc_get(nfsd_serv); 314 return 0; 315 } 316 if (nfsd_max_blksize == 0) { 317 /* choose a suitable default */ 318 struct sysinfo i; 319 si_meminfo(&i); 320 /* Aim for 1/4096 of memory per thread 321 * This gives 1MB on 4Gig machines 322 * But only uses 32K on 128M machines. 323 * Bottom out at 8K on 32M and smaller. 324 * Of course, this is only a default. 325 */ 326 nfsd_max_blksize = NFSSVC_MAXBLKSIZE; 327 i.totalram <<= PAGE_SHIFT - 12; 328 while (nfsd_max_blksize > i.totalram && 329 nfsd_max_blksize >= 8*1024*2) 330 nfsd_max_blksize /= 2; 331 } 332 nfsd_reset_versions(); 333 334 nfsd_serv = svc_create_pooled(&nfsd_program, nfsd_max_blksize, 335 nfsd_last_thread, nfsd, THIS_MODULE); 336 if (nfsd_serv == NULL) 337 return -ENOMEM; 338 339 set_max_drc(); 340 do_gettimeofday(&nfssvc_boot); /* record boot time */ 341 return err; 342 } 343 344 int nfsd_nrpools(void) 345 { 346 if (nfsd_serv == NULL) 347 return 0; 348 else 349 return nfsd_serv->sv_nrpools; 350 } 351 352 int nfsd_get_nrthreads(int n, int *nthreads) 353 { 354 int i = 0; 355 356 if (nfsd_serv != NULL) { 357 for (i = 0; i < nfsd_serv->sv_nrpools && i < n; i++) 358 nthreads[i] = nfsd_serv->sv_pools[i].sp_nrthreads; 359 } 360 361 return 0; 362 } 363 364 int nfsd_set_nrthreads(int n, int *nthreads) 365 { 366 int i = 0; 367 int tot = 0; 368 int err = 0; 369 370 WARN_ON(!mutex_is_locked(&nfsd_mutex)); 371 372 if (nfsd_serv == NULL || n <= 0) 373 return 0; 374 375 if (n > nfsd_serv->sv_nrpools) 376 n = nfsd_serv->sv_nrpools; 377 378 /* enforce a global maximum number of threads */ 379 tot = 0; 380 for (i = 0; i < n; i++) { 381 if (nthreads[i] > NFSD_MAXSERVS) 382 nthreads[i] = NFSD_MAXSERVS; 383 tot += nthreads[i]; 384 } 385 if (tot > NFSD_MAXSERVS) { 386 /* total too large: scale down requested numbers */ 387 for (i = 0; i < n && tot > 0; i++) { 388 int new = nthreads[i] * NFSD_MAXSERVS / tot; 389 tot -= (nthreads[i] - new); 390 nthreads[i] = new; 391 } 392 for (i = 0; i < n && tot > 0; i++) { 393 nthreads[i]--; 394 tot--; 395 } 396 } 397 398 /* 399 * There must always be a thread in pool 0; the admin 400 * can't shut down NFS completely using pool_threads. 401 */ 402 if (nthreads[0] == 0) 403 nthreads[0] = 1; 404 405 /* apply the new numbers */ 406 svc_get(nfsd_serv); 407 for (i = 0; i < n; i++) { 408 err = svc_set_num_threads(nfsd_serv, &nfsd_serv->sv_pools[i], 409 nthreads[i]); 410 if (err) 411 break; 412 } 413 svc_destroy(nfsd_serv); 414 415 return err; 416 } 417 418 /* 419 * Adjust the number of threads and return the new number of threads. 420 * This is also the function that starts the server if necessary, if 421 * this is the first time nrservs is nonzero. 422 */ 423 int 424 nfsd_svc(unsigned short port, int nrservs) 425 { 426 int error; 427 bool nfsd_up_before; 428 429 mutex_lock(&nfsd_mutex); 430 dprintk("nfsd: creating service\n"); 431 if (nrservs <= 0) 432 nrservs = 0; 433 if (nrservs > NFSD_MAXSERVS) 434 nrservs = NFSD_MAXSERVS; 435 error = 0; 436 if (nrservs == 0 && nfsd_serv == NULL) 437 goto out; 438 439 error = nfsd_create_serv(); 440 if (error) 441 goto out; 442 443 nfsd_up_before = nfsd_up; 444 445 error = nfsd_startup(port, nrservs); 446 if (error) 447 goto out_destroy; 448 error = svc_set_num_threads(nfsd_serv, NULL, nrservs); 449 if (error) 450 goto out_shutdown; 451 /* We are holding a reference to nfsd_serv which 452 * we don't want to count in the return value, 453 * so subtract 1 454 */ 455 error = nfsd_serv->sv_nrthreads - 1; 456 out_shutdown: 457 if (error < 0 && !nfsd_up_before) 458 nfsd_shutdown(); 459 out_destroy: 460 svc_destroy(nfsd_serv); /* Release server */ 461 out: 462 mutex_unlock(&nfsd_mutex); 463 return error; 464 } 465 466 467 /* 468 * This is the NFS server kernel thread 469 */ 470 static int 471 nfsd(void *vrqstp) 472 { 473 struct svc_rqst *rqstp = (struct svc_rqst *) vrqstp; 474 int err, preverr = 0; 475 476 /* Lock module and set up kernel thread */ 477 mutex_lock(&nfsd_mutex); 478 479 /* At this point, the thread shares current->fs 480 * with the init process. We need to create files with a 481 * umask of 0 instead of init's umask. */ 482 if (unshare_fs_struct() < 0) { 483 printk("Unable to start nfsd thread: out of memory\n"); 484 goto out; 485 } 486 487 current->fs->umask = 0; 488 489 /* 490 * thread is spawned with all signals set to SIG_IGN, re-enable 491 * the ones that will bring down the thread 492 */ 493 allow_signal(SIGKILL); 494 allow_signal(SIGHUP); 495 allow_signal(SIGINT); 496 allow_signal(SIGQUIT); 497 498 nfsdstats.th_cnt++; 499 mutex_unlock(&nfsd_mutex); 500 501 /* 502 * We want less throttling in balance_dirty_pages() so that nfs to 503 * localhost doesn't cause nfsd to lock up due to all the client's 504 * dirty pages. 505 */ 506 current->flags |= PF_LESS_THROTTLE; 507 set_freezable(); 508 509 /* 510 * The main request loop 511 */ 512 for (;;) { 513 /* 514 * Find a socket with data available and call its 515 * recvfrom routine. 516 */ 517 while ((err = svc_recv(rqstp, 60*60*HZ)) == -EAGAIN) 518 ; 519 if (err == -EINTR) 520 break; 521 else if (err < 0) { 522 if (err != preverr) { 523 printk(KERN_WARNING "%s: unexpected error " 524 "from svc_recv (%d)\n", __func__, -err); 525 preverr = err; 526 } 527 schedule_timeout_uninterruptible(HZ); 528 continue; 529 } 530 531 532 /* Lock the export hash tables for reading. */ 533 exp_readlock(); 534 535 validate_process_creds(); 536 svc_process(rqstp); 537 validate_process_creds(); 538 539 /* Unlock export hash tables */ 540 exp_readunlock(); 541 } 542 543 /* Clear signals before calling svc_exit_thread() */ 544 flush_signals(current); 545 546 mutex_lock(&nfsd_mutex); 547 nfsdstats.th_cnt --; 548 549 out: 550 /* Release the thread */ 551 svc_exit_thread(rqstp); 552 553 /* Release module */ 554 mutex_unlock(&nfsd_mutex); 555 module_put_and_exit(0); 556 return 0; 557 } 558 559 static __be32 map_new_errors(u32 vers, __be32 nfserr) 560 { 561 if (nfserr == nfserr_jukebox && vers == 2) 562 return nfserr_dropit; 563 if (nfserr == nfserr_wrongsec && vers < 4) 564 return nfserr_acces; 565 return nfserr; 566 } 567 568 int 569 nfsd_dispatch(struct svc_rqst *rqstp, __be32 *statp) 570 { 571 struct svc_procedure *proc; 572 kxdrproc_t xdr; 573 __be32 nfserr; 574 __be32 *nfserrp; 575 576 dprintk("nfsd_dispatch: vers %d proc %d\n", 577 rqstp->rq_vers, rqstp->rq_proc); 578 proc = rqstp->rq_procinfo; 579 580 /* Check whether we have this call in the cache. */ 581 switch (nfsd_cache_lookup(rqstp, proc->pc_cachetype)) { 582 case RC_INTR: 583 case RC_DROPIT: 584 return 0; 585 case RC_REPLY: 586 return 1; 587 case RC_DOIT:; 588 /* do it */ 589 } 590 591 /* Decode arguments */ 592 xdr = proc->pc_decode; 593 if (xdr && !xdr(rqstp, (__be32*)rqstp->rq_arg.head[0].iov_base, 594 rqstp->rq_argp)) { 595 dprintk("nfsd: failed to decode arguments!\n"); 596 nfsd_cache_update(rqstp, RC_NOCACHE, NULL); 597 *statp = rpc_garbage_args; 598 return 1; 599 } 600 601 /* need to grab the location to store the status, as 602 * nfsv4 does some encoding while processing 603 */ 604 nfserrp = rqstp->rq_res.head[0].iov_base 605 + rqstp->rq_res.head[0].iov_len; 606 rqstp->rq_res.head[0].iov_len += sizeof(__be32); 607 608 /* Now call the procedure handler, and encode NFS status. */ 609 nfserr = proc->pc_func(rqstp, rqstp->rq_argp, rqstp->rq_resp); 610 nfserr = map_new_errors(rqstp->rq_vers, nfserr); 611 if (nfserr == nfserr_dropit || rqstp->rq_dropme) { 612 dprintk("nfsd: Dropping request; may be revisited later\n"); 613 nfsd_cache_update(rqstp, RC_NOCACHE, NULL); 614 return 0; 615 } 616 617 if (rqstp->rq_proc != 0) 618 *nfserrp++ = nfserr; 619 620 /* Encode result. 621 * For NFSv2, additional info is never returned in case of an error. 622 */ 623 if (!(nfserr && rqstp->rq_vers == 2)) { 624 xdr = proc->pc_encode; 625 if (xdr && !xdr(rqstp, nfserrp, 626 rqstp->rq_resp)) { 627 /* Failed to encode result. Release cache entry */ 628 dprintk("nfsd: failed to encode result!\n"); 629 nfsd_cache_update(rqstp, RC_NOCACHE, NULL); 630 *statp = rpc_system_err; 631 return 1; 632 } 633 } 634 635 /* Store reply in cache. */ 636 nfsd_cache_update(rqstp, proc->pc_cachetype, statp + 1); 637 return 1; 638 } 639 640 int nfsd_pool_stats_open(struct inode *inode, struct file *file) 641 { 642 int ret; 643 mutex_lock(&nfsd_mutex); 644 if (nfsd_serv == NULL) { 645 mutex_unlock(&nfsd_mutex); 646 return -ENODEV; 647 } 648 /* bump up the psudo refcount while traversing */ 649 svc_get(nfsd_serv); 650 ret = svc_pool_stats_open(nfsd_serv, file); 651 mutex_unlock(&nfsd_mutex); 652 return ret; 653 } 654 655 int nfsd_pool_stats_release(struct inode *inode, struct file *file) 656 { 657 int ret = seq_release(inode, file); 658 mutex_lock(&nfsd_mutex); 659 /* this function really, really should have been called svc_put() */ 660 svc_destroy(nfsd_serv); 661 mutex_unlock(&nfsd_mutex); 662 return ret; 663 } 664