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