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/config.h> 12 #include <linux/module.h> 13 14 #include <linux/time.h> 15 #include <linux/errno.h> 16 #include <linux/nfs.h> 17 #include <linux/in.h> 18 #include <linux/uio.h> 19 #include <linux/unistd.h> 20 #include <linux/slab.h> 21 #include <linux/smp.h> 22 #include <linux/smp_lock.h> 23 #include <linux/fs_struct.h> 24 25 #include <linux/sunrpc/types.h> 26 #include <linux/sunrpc/stats.h> 27 #include <linux/sunrpc/svc.h> 28 #include <linux/sunrpc/svcsock.h> 29 #include <linux/sunrpc/cache.h> 30 #include <linux/nfsd/nfsd.h> 31 #include <linux/nfsd/stats.h> 32 #include <linux/nfsd/cache.h> 33 #include <linux/nfsd/syscall.h> 34 #include <linux/lockd/bind.h> 35 #include <linux/nfsacl.h> 36 37 #define NFSDDBG_FACILITY NFSDDBG_SVC 38 39 /* these signals will be delivered to an nfsd thread 40 * when handling a request 41 */ 42 #define ALLOWED_SIGS (sigmask(SIGKILL)) 43 /* these signals will be delivered to an nfsd thread 44 * when not handling a request. i.e. when waiting 45 */ 46 #define SHUTDOWN_SIGS (sigmask(SIGKILL) | sigmask(SIGHUP) | sigmask(SIGINT) | sigmask(SIGQUIT)) 47 /* if the last thread dies with SIGHUP, then the exports table is 48 * left unchanged ( like 2.4-{0-9} ). Any other signal will clear 49 * the exports table (like 2.2). 50 */ 51 #define SIG_NOCLEAN SIGHUP 52 53 extern struct svc_program nfsd_program; 54 static void nfsd(struct svc_rqst *rqstp); 55 struct timeval nfssvc_boot; 56 struct svc_serv *nfsd_serv; 57 static atomic_t nfsd_busy; 58 static unsigned long nfsd_last_call; 59 static DEFINE_SPINLOCK(nfsd_call_lock); 60 61 struct nfsd_list { 62 struct list_head list; 63 struct task_struct *task; 64 }; 65 static struct list_head nfsd_list = LIST_HEAD_INIT(nfsd_list); 66 67 #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL) 68 static struct svc_stat nfsd_acl_svcstats; 69 static struct svc_version * nfsd_acl_version[] = { 70 [2] = &nfsd_acl_version2, 71 [3] = &nfsd_acl_version3, 72 }; 73 74 #define NFSD_ACL_MINVERS 2 75 #define NFSD_ACL_NRVERS ARRAY_SIZE(nfsd_acl_version) 76 static struct svc_version *nfsd_acl_versions[NFSD_ACL_NRVERS]; 77 78 static struct svc_program nfsd_acl_program = { 79 .pg_prog = NFS_ACL_PROGRAM, 80 .pg_nvers = NFSD_ACL_NRVERS, 81 .pg_vers = nfsd_acl_versions, 82 .pg_name = "nfsd", 83 .pg_class = "nfsd", 84 .pg_stats = &nfsd_acl_svcstats, 85 .pg_authenticate = &svc_set_client, 86 }; 87 88 static struct svc_stat nfsd_acl_svcstats = { 89 .program = &nfsd_acl_program, 90 }; 91 #endif /* defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL) */ 92 93 static struct svc_version * nfsd_version[] = { 94 [2] = &nfsd_version2, 95 #if defined(CONFIG_NFSD_V3) 96 [3] = &nfsd_version3, 97 #endif 98 #if defined(CONFIG_NFSD_V4) 99 [4] = &nfsd_version4, 100 #endif 101 }; 102 103 #define NFSD_MINVERS 2 104 #define NFSD_NRVERS ARRAY_SIZE(nfsd_version) 105 static struct svc_version *nfsd_versions[NFSD_NRVERS]; 106 107 struct svc_program nfsd_program = { 108 #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL) 109 .pg_next = &nfsd_acl_program, 110 #endif 111 .pg_prog = NFS_PROGRAM, /* program number */ 112 .pg_nvers = NFSD_NRVERS, /* nr of entries in nfsd_version */ 113 .pg_vers = nfsd_versions, /* version table */ 114 .pg_name = "nfsd", /* program name */ 115 .pg_class = "nfsd", /* authentication class */ 116 .pg_stats = &nfsd_svcstats, /* version table */ 117 .pg_authenticate = &svc_set_client, /* export authentication */ 118 119 }; 120 121 /* 122 * Maximum number of nfsd processes 123 */ 124 #define NFSD_MAXSERVS 8192 125 126 int nfsd_nrthreads(void) 127 { 128 if (nfsd_serv == NULL) 129 return 0; 130 else 131 return nfsd_serv->sv_nrthreads; 132 } 133 134 int 135 nfsd_svc(unsigned short port, int nrservs) 136 { 137 int error; 138 int none_left, found_one, i; 139 struct list_head *victim; 140 141 lock_kernel(); 142 dprintk("nfsd: creating service: vers 0x%x\n", 143 nfsd_versbits); 144 error = -EINVAL; 145 if (nrservs <= 0) 146 nrservs = 0; 147 if (nrservs > NFSD_MAXSERVS) 148 nrservs = NFSD_MAXSERVS; 149 150 /* Readahead param cache - will no-op if it already exists */ 151 error = nfsd_racache_init(2*nrservs); 152 if (error<0) 153 goto out; 154 error = nfs4_state_start(); 155 if (error<0) 156 goto out; 157 if (!nfsd_serv) { 158 /* 159 * Use the nfsd_ctlbits to define which 160 * versions that will be advertised. 161 * If nfsd_ctlbits doesn't list any version, 162 * export them all. 163 */ 164 found_one = 0; 165 166 for (i = NFSD_MINVERS; i < NFSD_NRVERS; i++) { 167 if (NFSCTL_VERISSET(nfsd_versbits, i)) { 168 nfsd_program.pg_vers[i] = nfsd_version[i]; 169 found_one = 1; 170 } else 171 nfsd_program.pg_vers[i] = NULL; 172 } 173 174 if (!found_one) { 175 for (i = NFSD_MINVERS; i < NFSD_NRVERS; i++) 176 nfsd_program.pg_vers[i] = nfsd_version[i]; 177 } 178 179 180 #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL) 181 found_one = 0; 182 183 for (i = NFSD_ACL_MINVERS; i < NFSD_ACL_NRVERS; i++) { 184 if (NFSCTL_VERISSET(nfsd_versbits, i)) { 185 nfsd_acl_program.pg_vers[i] = 186 nfsd_acl_version[i]; 187 found_one = 1; 188 } else 189 nfsd_acl_program.pg_vers[i] = NULL; 190 } 191 192 if (!found_one) { 193 for (i = NFSD_ACL_MINVERS; i < NFSD_ACL_NRVERS; i++) 194 nfsd_acl_program.pg_vers[i] = 195 nfsd_acl_version[i]; 196 } 197 #endif 198 199 atomic_set(&nfsd_busy, 0); 200 error = -ENOMEM; 201 nfsd_serv = svc_create(&nfsd_program, NFSD_BUFSIZE); 202 if (nfsd_serv == NULL) 203 goto out; 204 error = svc_makesock(nfsd_serv, IPPROTO_UDP, port); 205 if (error < 0) 206 goto failure; 207 208 #ifdef CONFIG_NFSD_TCP 209 error = svc_makesock(nfsd_serv, IPPROTO_TCP, port); 210 if (error < 0) 211 goto failure; 212 #endif 213 do_gettimeofday(&nfssvc_boot); /* record boot time */ 214 } else 215 nfsd_serv->sv_nrthreads++; 216 nrservs -= (nfsd_serv->sv_nrthreads-1); 217 while (nrservs > 0) { 218 nrservs--; 219 __module_get(THIS_MODULE); 220 error = svc_create_thread(nfsd, nfsd_serv); 221 if (error < 0) { 222 module_put(THIS_MODULE); 223 break; 224 } 225 } 226 victim = nfsd_list.next; 227 while (nrservs < 0 && victim != &nfsd_list) { 228 struct nfsd_list *nl = 229 list_entry(victim,struct nfsd_list, list); 230 victim = victim->next; 231 send_sig(SIG_NOCLEAN, nl->task, 1); 232 nrservs++; 233 } 234 failure: 235 none_left = (nfsd_serv->sv_nrthreads == 1); 236 svc_destroy(nfsd_serv); /* Release server */ 237 if (none_left) { 238 nfsd_serv = NULL; 239 nfsd_racache_shutdown(); 240 nfs4_state_shutdown(); 241 } 242 out: 243 unlock_kernel(); 244 return error; 245 } 246 247 static inline void 248 update_thread_usage(int busy_threads) 249 { 250 unsigned long prev_call; 251 unsigned long diff; 252 int decile; 253 254 spin_lock(&nfsd_call_lock); 255 prev_call = nfsd_last_call; 256 nfsd_last_call = jiffies; 257 decile = busy_threads*10/nfsdstats.th_cnt; 258 if (decile>0 && decile <= 10) { 259 diff = nfsd_last_call - prev_call; 260 if ( (nfsdstats.th_usage[decile-1] += diff) >= NFSD_USAGE_WRAP) 261 nfsdstats.th_usage[decile-1] -= NFSD_USAGE_WRAP; 262 if (decile == 10) 263 nfsdstats.th_fullcnt++; 264 } 265 spin_unlock(&nfsd_call_lock); 266 } 267 268 /* 269 * This is the NFS server kernel thread 270 */ 271 static void 272 nfsd(struct svc_rqst *rqstp) 273 { 274 struct svc_serv *serv = rqstp->rq_server; 275 struct fs_struct *fsp; 276 int err; 277 struct nfsd_list me; 278 sigset_t shutdown_mask, allowed_mask; 279 280 /* Lock module and set up kernel thread */ 281 lock_kernel(); 282 daemonize("nfsd"); 283 284 /* After daemonize() this kernel thread shares current->fs 285 * with the init process. We need to create files with a 286 * umask of 0 instead of init's umask. */ 287 fsp = copy_fs_struct(current->fs); 288 if (!fsp) { 289 printk("Unable to start nfsd thread: out of memory\n"); 290 goto out; 291 } 292 exit_fs(current); 293 current->fs = fsp; 294 current->fs->umask = 0; 295 296 siginitsetinv(&shutdown_mask, SHUTDOWN_SIGS); 297 siginitsetinv(&allowed_mask, ALLOWED_SIGS); 298 299 nfsdstats.th_cnt++; 300 301 lockd_up(); /* start lockd */ 302 303 me.task = current; 304 list_add(&me.list, &nfsd_list); 305 306 unlock_kernel(); 307 308 /* 309 * We want less throttling in balance_dirty_pages() so that nfs to 310 * localhost doesn't cause nfsd to lock up due to all the client's 311 * dirty pages. 312 */ 313 current->flags |= PF_LESS_THROTTLE; 314 315 /* 316 * The main request loop 317 */ 318 for (;;) { 319 /* Block all but the shutdown signals */ 320 sigprocmask(SIG_SETMASK, &shutdown_mask, NULL); 321 322 /* 323 * Find a socket with data available and call its 324 * recvfrom routine. 325 */ 326 while ((err = svc_recv(serv, rqstp, 327 60*60*HZ)) == -EAGAIN) 328 ; 329 if (err < 0) 330 break; 331 update_thread_usage(atomic_read(&nfsd_busy)); 332 atomic_inc(&nfsd_busy); 333 334 /* Lock the export hash tables for reading. */ 335 exp_readlock(); 336 337 /* Process request with signals blocked. */ 338 sigprocmask(SIG_SETMASK, &allowed_mask, NULL); 339 340 svc_process(serv, rqstp); 341 342 /* Unlock export hash tables */ 343 exp_readunlock(); 344 update_thread_usage(atomic_read(&nfsd_busy)); 345 atomic_dec(&nfsd_busy); 346 } 347 348 if (err != -EINTR) { 349 printk(KERN_WARNING "nfsd: terminating on error %d\n", -err); 350 } else { 351 unsigned int signo; 352 353 for (signo = 1; signo <= _NSIG; signo++) 354 if (sigismember(¤t->pending.signal, signo) && 355 !sigismember(¤t->blocked, signo)) 356 break; 357 err = signo; 358 } 359 /* Clear signals before calling lockd_down() and svc_exit_thread() */ 360 flush_signals(current); 361 362 lock_kernel(); 363 364 /* Release lockd */ 365 lockd_down(); 366 367 /* Check if this is last thread */ 368 if (serv->sv_nrthreads==1) { 369 370 printk(KERN_WARNING "nfsd: last server has exited\n"); 371 if (err != SIG_NOCLEAN) { 372 printk(KERN_WARNING "nfsd: unexporting all filesystems\n"); 373 nfsd_export_flush(); 374 } 375 nfsd_serv = NULL; 376 nfsd_racache_shutdown(); /* release read-ahead cache */ 377 nfs4_state_shutdown(); 378 } 379 list_del(&me.list); 380 nfsdstats.th_cnt --; 381 382 out: 383 /* Release the thread */ 384 svc_exit_thread(rqstp); 385 386 /* Release module */ 387 unlock_kernel(); 388 module_put_and_exit(0); 389 } 390 391 int 392 nfsd_dispatch(struct svc_rqst *rqstp, u32 *statp) 393 { 394 struct svc_procedure *proc; 395 kxdrproc_t xdr; 396 u32 nfserr; 397 u32 *nfserrp; 398 399 dprintk("nfsd_dispatch: vers %d proc %d\n", 400 rqstp->rq_vers, rqstp->rq_proc); 401 proc = rqstp->rq_procinfo; 402 403 /* Check whether we have this call in the cache. */ 404 switch (nfsd_cache_lookup(rqstp, proc->pc_cachetype)) { 405 case RC_INTR: 406 case RC_DROPIT: 407 return 0; 408 case RC_REPLY: 409 return 1; 410 case RC_DOIT:; 411 /* do it */ 412 } 413 414 /* Decode arguments */ 415 xdr = proc->pc_decode; 416 if (xdr && !xdr(rqstp, (u32*)rqstp->rq_arg.head[0].iov_base, 417 rqstp->rq_argp)) { 418 dprintk("nfsd: failed to decode arguments!\n"); 419 nfsd_cache_update(rqstp, RC_NOCACHE, NULL); 420 *statp = rpc_garbage_args; 421 return 1; 422 } 423 424 /* need to grab the location to store the status, as 425 * nfsv4 does some encoding while processing 426 */ 427 nfserrp = rqstp->rq_res.head[0].iov_base 428 + rqstp->rq_res.head[0].iov_len; 429 rqstp->rq_res.head[0].iov_len += sizeof(u32); 430 431 /* Now call the procedure handler, and encode NFS status. */ 432 nfserr = proc->pc_func(rqstp, rqstp->rq_argp, rqstp->rq_resp); 433 if (nfserr == nfserr_jukebox && rqstp->rq_vers == 2) 434 nfserr = nfserr_dropit; 435 if (nfserr == nfserr_dropit) { 436 dprintk("nfsd: Dropping request due to malloc failure!\n"); 437 nfsd_cache_update(rqstp, RC_NOCACHE, NULL); 438 return 0; 439 } 440 441 if (rqstp->rq_proc != 0) 442 *nfserrp++ = nfserr; 443 444 /* Encode result. 445 * For NFSv2, additional info is never returned in case of an error. 446 */ 447 if (!(nfserr && rqstp->rq_vers == 2)) { 448 xdr = proc->pc_encode; 449 if (xdr && !xdr(rqstp, nfserrp, 450 rqstp->rq_resp)) { 451 /* Failed to encode result. Release cache entry */ 452 dprintk("nfsd: failed to encode result!\n"); 453 nfsd_cache_update(rqstp, RC_NOCACHE, NULL); 454 *statp = rpc_system_err; 455 return 1; 456 } 457 } 458 459 /* Store reply in cache. */ 460 nfsd_cache_update(rqstp, proc->pc_cachetype, statp + 1); 461 return 1; 462 } 463