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