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