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 38 #define NFSDDBG_FACILITY NFSDDBG_SVC 39 40 extern struct svc_program nfsd_program; 41 static int nfsd(void *vrqstp); 42 struct timeval nfssvc_boot; 43 44 /* 45 * nfsd_mutex protects nfsd_serv -- both the pointer itself and the members 46 * of the svc_serv struct. In particular, ->sv_nrthreads but also to some 47 * extent ->sv_temp_socks and ->sv_permsocks. It also protects nfsdstats.th_cnt 48 * 49 * If (out side the lock) nfsd_serv is non-NULL, then it must point to a 50 * properly initialised 'struct svc_serv' with ->sv_nrthreads > 0. That number 51 * of nfsd threads must exist and each must listed in ->sp_all_threads in each 52 * entry of ->sv_pools[]. 53 * 54 * Transitions of the thread count between zero and non-zero are of particular 55 * interest since the svc_serv needs to be created and initialized at that 56 * point, or freed. 57 * 58 * Finally, the nfsd_mutex also protects some of the global variables that are 59 * accessed when nfsd starts and that are settable via the write_* routines in 60 * nfsctl.c. In particular: 61 * 62 * user_recovery_dirname 63 * user_lease_time 64 * nfsd_versions 65 */ 66 DEFINE_MUTEX(nfsd_mutex); 67 struct svc_serv *nfsd_serv; 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 u32 nfsd_supported_minorversion; 124 125 int nfsd_vers(int vers, enum vers_op change) 126 { 127 if (vers < NFSD_MINVERS || vers >= NFSD_NRVERS) 128 return -1; 129 switch(change) { 130 case NFSD_SET: 131 nfsd_versions[vers] = nfsd_version[vers]; 132 #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL) 133 if (vers < NFSD_ACL_NRVERS) 134 nfsd_acl_versions[vers] = nfsd_acl_version[vers]; 135 #endif 136 break; 137 case NFSD_CLEAR: 138 nfsd_versions[vers] = NULL; 139 #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL) 140 if (vers < NFSD_ACL_NRVERS) 141 nfsd_acl_versions[vers] = NULL; 142 #endif 143 break; 144 case NFSD_TEST: 145 return nfsd_versions[vers] != NULL; 146 case NFSD_AVAIL: 147 return nfsd_version[vers] != NULL; 148 } 149 return 0; 150 } 151 152 int nfsd_minorversion(u32 minorversion, enum vers_op change) 153 { 154 if (minorversion > NFSD_SUPPORTED_MINOR_VERSION) 155 return -1; 156 switch(change) { 157 case NFSD_SET: 158 nfsd_supported_minorversion = minorversion; 159 break; 160 case NFSD_CLEAR: 161 if (minorversion == 0) 162 return -1; 163 nfsd_supported_minorversion = minorversion - 1; 164 break; 165 case NFSD_TEST: 166 return minorversion <= nfsd_supported_minorversion; 167 case NFSD_AVAIL: 168 return minorversion <= NFSD_SUPPORTED_MINOR_VERSION; 169 } 170 return 0; 171 } 172 173 /* 174 * Maximum number of nfsd processes 175 */ 176 #define NFSD_MAXSERVS 8192 177 178 int nfsd_nrthreads(void) 179 { 180 int rv = 0; 181 mutex_lock(&nfsd_mutex); 182 if (nfsd_serv) 183 rv = nfsd_serv->sv_nrthreads; 184 mutex_unlock(&nfsd_mutex); 185 return rv; 186 } 187 188 static void nfsd_last_thread(struct svc_serv *serv) 189 { 190 /* When last nfsd thread exits we need to do some clean-up */ 191 struct svc_xprt *xprt; 192 list_for_each_entry(xprt, &serv->sv_permsocks, xpt_list) 193 lockd_down(); 194 nfsd_serv = NULL; 195 nfsd_racache_shutdown(); 196 nfs4_state_shutdown(); 197 198 printk(KERN_WARNING "nfsd: last server has exited, flushing export " 199 "cache\n"); 200 nfsd_export_flush(); 201 } 202 203 void nfsd_reset_versions(void) 204 { 205 int found_one = 0; 206 int i; 207 208 for (i = NFSD_MINVERS; i < NFSD_NRVERS; i++) { 209 if (nfsd_program.pg_vers[i]) 210 found_one = 1; 211 } 212 213 if (!found_one) { 214 for (i = NFSD_MINVERS; i < NFSD_NRVERS; i++) 215 nfsd_program.pg_vers[i] = nfsd_version[i]; 216 #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL) 217 for (i = NFSD_ACL_MINVERS; i < NFSD_ACL_NRVERS; i++) 218 nfsd_acl_program.pg_vers[i] = 219 nfsd_acl_version[i]; 220 #endif 221 } 222 } 223 224 /* 225 * Each session guarantees a negotiated per slot memory cache for replies 226 * which in turn consumes memory beyond the v2/v3/v4.0 server. A dedicated 227 * NFSv4.1 server might want to use more memory for a DRC than a machine 228 * with mutiple services. 229 * 230 * Impose a hard limit on the number of pages for the DRC which varies 231 * according to the machines free pages. This is of course only a default. 232 * 233 * For now this is a #defined shift which could be under admin control 234 * in the future. 235 */ 236 static void set_max_drc(void) 237 { 238 /* The percent of nr_free_buffer_pages used by the V4.1 server DRC */ 239 #define NFSD_DRC_SIZE_SHIFT 7 240 nfsd_serv->sv_drc_max_pages = nr_free_buffer_pages() 241 >> NFSD_DRC_SIZE_SHIFT; 242 nfsd_serv->sv_drc_pages_used = 0; 243 dprintk("%s svc_drc_max_pages %u\n", __func__, 244 nfsd_serv->sv_drc_max_pages); 245 } 246 247 int nfsd_create_serv(void) 248 { 249 int err = 0; 250 251 WARN_ON(!mutex_is_locked(&nfsd_mutex)); 252 if (nfsd_serv) { 253 svc_get(nfsd_serv); 254 return 0; 255 } 256 if (nfsd_max_blksize == 0) { 257 /* choose a suitable default */ 258 struct sysinfo i; 259 si_meminfo(&i); 260 /* Aim for 1/4096 of memory per thread 261 * This gives 1MB on 4Gig machines 262 * But only uses 32K on 128M machines. 263 * Bottom out at 8K on 32M and smaller. 264 * Of course, this is only a default. 265 */ 266 nfsd_max_blksize = NFSSVC_MAXBLKSIZE; 267 i.totalram <<= PAGE_SHIFT - 12; 268 while (nfsd_max_blksize > i.totalram && 269 nfsd_max_blksize >= 8*1024*2) 270 nfsd_max_blksize /= 2; 271 } 272 273 nfsd_serv = svc_create_pooled(&nfsd_program, nfsd_max_blksize, 274 nfsd_last_thread, nfsd, THIS_MODULE); 275 if (nfsd_serv == NULL) 276 err = -ENOMEM; 277 else 278 set_max_drc(); 279 280 do_gettimeofday(&nfssvc_boot); /* record boot time */ 281 return err; 282 } 283 284 static int nfsd_init_socks(int port) 285 { 286 int error; 287 if (!list_empty(&nfsd_serv->sv_permsocks)) 288 return 0; 289 290 error = svc_create_xprt(nfsd_serv, "udp", PF_INET, port, 291 SVC_SOCK_DEFAULTS); 292 if (error < 0) 293 return error; 294 295 error = lockd_up(); 296 if (error < 0) 297 return error; 298 299 error = svc_create_xprt(nfsd_serv, "tcp", PF_INET, port, 300 SVC_SOCK_DEFAULTS); 301 if (error < 0) 302 return error; 303 304 error = lockd_up(); 305 if (error < 0) 306 return error; 307 308 return 0; 309 } 310 311 int nfsd_nrpools(void) 312 { 313 if (nfsd_serv == NULL) 314 return 0; 315 else 316 return nfsd_serv->sv_nrpools; 317 } 318 319 int nfsd_get_nrthreads(int n, int *nthreads) 320 { 321 int i = 0; 322 323 if (nfsd_serv != NULL) { 324 for (i = 0; i < nfsd_serv->sv_nrpools && i < n; i++) 325 nthreads[i] = nfsd_serv->sv_pools[i].sp_nrthreads; 326 } 327 328 return 0; 329 } 330 331 int nfsd_set_nrthreads(int n, int *nthreads) 332 { 333 int i = 0; 334 int tot = 0; 335 int err = 0; 336 337 WARN_ON(!mutex_is_locked(&nfsd_mutex)); 338 339 if (nfsd_serv == NULL || n <= 0) 340 return 0; 341 342 if (n > nfsd_serv->sv_nrpools) 343 n = nfsd_serv->sv_nrpools; 344 345 /* enforce a global maximum number of threads */ 346 tot = 0; 347 for (i = 0; i < n; i++) { 348 if (nthreads[i] > NFSD_MAXSERVS) 349 nthreads[i] = NFSD_MAXSERVS; 350 tot += nthreads[i]; 351 } 352 if (tot > NFSD_MAXSERVS) { 353 /* total too large: scale down requested numbers */ 354 for (i = 0; i < n && tot > 0; i++) { 355 int new = nthreads[i] * NFSD_MAXSERVS / tot; 356 tot -= (nthreads[i] - new); 357 nthreads[i] = new; 358 } 359 for (i = 0; i < n && tot > 0; i++) { 360 nthreads[i]--; 361 tot--; 362 } 363 } 364 365 /* 366 * There must always be a thread in pool 0; the admin 367 * can't shut down NFS completely using pool_threads. 368 */ 369 if (nthreads[0] == 0) 370 nthreads[0] = 1; 371 372 /* apply the new numbers */ 373 svc_get(nfsd_serv); 374 for (i = 0; i < n; i++) { 375 err = svc_set_num_threads(nfsd_serv, &nfsd_serv->sv_pools[i], 376 nthreads[i]); 377 if (err) 378 break; 379 } 380 svc_destroy(nfsd_serv); 381 382 return err; 383 } 384 385 int 386 nfsd_svc(unsigned short port, int nrservs) 387 { 388 int error; 389 390 mutex_lock(&nfsd_mutex); 391 dprintk("nfsd: creating service\n"); 392 if (nrservs <= 0) 393 nrservs = 0; 394 if (nrservs > NFSD_MAXSERVS) 395 nrservs = NFSD_MAXSERVS; 396 error = 0; 397 if (nrservs == 0 && nfsd_serv == NULL) 398 goto out; 399 400 /* Readahead param cache - will no-op if it already exists */ 401 error = nfsd_racache_init(2*nrservs); 402 if (error<0) 403 goto out; 404 nfs4_state_start(); 405 406 nfsd_reset_versions(); 407 408 error = nfsd_create_serv(); 409 410 if (error) 411 goto out; 412 error = nfsd_init_socks(port); 413 if (error) 414 goto failure; 415 416 error = svc_set_num_threads(nfsd_serv, NULL, nrservs); 417 if (error == 0) 418 /* We are holding a reference to nfsd_serv which 419 * we don't want to count in the return value, 420 * so subtract 1 421 */ 422 error = nfsd_serv->sv_nrthreads - 1; 423 failure: 424 svc_destroy(nfsd_serv); /* Release server */ 425 out: 426 mutex_unlock(&nfsd_mutex); 427 return error; 428 } 429 430 431 /* 432 * This is the NFS server kernel thread 433 */ 434 static int 435 nfsd(void *vrqstp) 436 { 437 struct svc_rqst *rqstp = (struct svc_rqst *) vrqstp; 438 int err, preverr = 0; 439 440 /* Lock module and set up kernel thread */ 441 mutex_lock(&nfsd_mutex); 442 443 /* At this point, the thread shares current->fs 444 * with the init process. We need to create files with a 445 * umask of 0 instead of init's umask. */ 446 if (unshare_fs_struct() < 0) { 447 printk("Unable to start nfsd thread: out of memory\n"); 448 goto out; 449 } 450 451 current->fs->umask = 0; 452 453 /* 454 * thread is spawned with all signals set to SIG_IGN, re-enable 455 * the ones that will bring down the thread 456 */ 457 allow_signal(SIGKILL); 458 allow_signal(SIGHUP); 459 allow_signal(SIGINT); 460 allow_signal(SIGQUIT); 461 462 nfsdstats.th_cnt++; 463 mutex_unlock(&nfsd_mutex); 464 465 /* 466 * We want less throttling in balance_dirty_pages() so that nfs to 467 * localhost doesn't cause nfsd to lock up due to all the client's 468 * dirty pages. 469 */ 470 current->flags |= PF_LESS_THROTTLE; 471 set_freezable(); 472 473 /* 474 * The main request loop 475 */ 476 for (;;) { 477 /* 478 * Find a socket with data available and call its 479 * recvfrom routine. 480 */ 481 while ((err = svc_recv(rqstp, 60*60*HZ)) == -EAGAIN) 482 ; 483 if (err == -EINTR) 484 break; 485 else if (err < 0) { 486 if (err != preverr) { 487 printk(KERN_WARNING "%s: unexpected error " 488 "from svc_recv (%d)\n", __func__, -err); 489 preverr = err; 490 } 491 schedule_timeout_uninterruptible(HZ); 492 continue; 493 } 494 495 496 /* Lock the export hash tables for reading. */ 497 exp_readlock(); 498 499 svc_process(rqstp); 500 501 /* Unlock export hash tables */ 502 exp_readunlock(); 503 } 504 505 /* Clear signals before calling svc_exit_thread() */ 506 flush_signals(current); 507 508 mutex_lock(&nfsd_mutex); 509 nfsdstats.th_cnt --; 510 511 out: 512 /* Release the thread */ 513 svc_exit_thread(rqstp); 514 515 /* Release module */ 516 mutex_unlock(&nfsd_mutex); 517 module_put_and_exit(0); 518 return 0; 519 } 520 521 static __be32 map_new_errors(u32 vers, __be32 nfserr) 522 { 523 if (nfserr == nfserr_jukebox && vers == 2) 524 return nfserr_dropit; 525 if (nfserr == nfserr_wrongsec && vers < 4) 526 return nfserr_acces; 527 return nfserr; 528 } 529 530 int 531 nfsd_dispatch(struct svc_rqst *rqstp, __be32 *statp) 532 { 533 struct svc_procedure *proc; 534 kxdrproc_t xdr; 535 __be32 nfserr; 536 __be32 *nfserrp; 537 538 dprintk("nfsd_dispatch: vers %d proc %d\n", 539 rqstp->rq_vers, rqstp->rq_proc); 540 proc = rqstp->rq_procinfo; 541 542 /* Check whether we have this call in the cache. */ 543 switch (nfsd_cache_lookup(rqstp, proc->pc_cachetype)) { 544 case RC_INTR: 545 case RC_DROPIT: 546 return 0; 547 case RC_REPLY: 548 return 1; 549 case RC_DOIT:; 550 /* do it */ 551 } 552 553 /* Decode arguments */ 554 xdr = proc->pc_decode; 555 if (xdr && !xdr(rqstp, (__be32*)rqstp->rq_arg.head[0].iov_base, 556 rqstp->rq_argp)) { 557 dprintk("nfsd: failed to decode arguments!\n"); 558 nfsd_cache_update(rqstp, RC_NOCACHE, NULL); 559 *statp = rpc_garbage_args; 560 return 1; 561 } 562 563 /* need to grab the location to store the status, as 564 * nfsv4 does some encoding while processing 565 */ 566 nfserrp = rqstp->rq_res.head[0].iov_base 567 + rqstp->rq_res.head[0].iov_len; 568 rqstp->rq_res.head[0].iov_len += sizeof(__be32); 569 570 /* NFSv4.1 DRC requires statp */ 571 if (rqstp->rq_vers == 4) 572 nfsd4_set_statp(rqstp, statp); 573 574 /* Now call the procedure handler, and encode NFS status. */ 575 nfserr = proc->pc_func(rqstp, rqstp->rq_argp, rqstp->rq_resp); 576 nfserr = map_new_errors(rqstp->rq_vers, nfserr); 577 if (nfserr == nfserr_dropit) { 578 dprintk("nfsd: Dropping request; may be revisited later\n"); 579 nfsd_cache_update(rqstp, RC_NOCACHE, NULL); 580 return 0; 581 } 582 583 if (rqstp->rq_proc != 0) 584 *nfserrp++ = nfserr; 585 586 /* Encode result. 587 * For NFSv2, additional info is never returned in case of an error. 588 */ 589 if (!(nfserr && rqstp->rq_vers == 2)) { 590 xdr = proc->pc_encode; 591 if (xdr && !xdr(rqstp, nfserrp, 592 rqstp->rq_resp)) { 593 /* Failed to encode result. Release cache entry */ 594 dprintk("nfsd: failed to encode result!\n"); 595 nfsd_cache_update(rqstp, RC_NOCACHE, NULL); 596 *statp = rpc_system_err; 597 return 1; 598 } 599 } 600 601 /* Store reply in cache. */ 602 nfsd_cache_update(rqstp, proc->pc_cachetype, statp + 1); 603 return 1; 604 } 605 606 int nfsd_pool_stats_open(struct inode *inode, struct file *file) 607 { 608 if (nfsd_serv == NULL) 609 return -ENODEV; 610 return svc_pool_stats_open(nfsd_serv, file); 611 } 612