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 35 #define NFSDDBG_FACILITY NFSDDBG_SVC 36 37 /* these signals will be delivered to an nfsd thread 38 * when handling a request 39 */ 40 #define ALLOWED_SIGS (sigmask(SIGKILL)) 41 /* these signals will be delivered to an nfsd thread 42 * when not handling a request. i.e. when waiting 43 */ 44 #define SHUTDOWN_SIGS (sigmask(SIGKILL) | sigmask(SIGHUP) | sigmask(SIGINT) | sigmask(SIGQUIT)) 45 /* if the last thread dies with SIGHUP, then the exports table is 46 * left unchanged ( like 2.4-{0-9} ). Any other signal will clear 47 * the exports table (like 2.2). 48 */ 49 #define SIG_NOCLEAN SIGHUP 50 51 extern struct svc_program nfsd_program; 52 static void nfsd(struct svc_rqst *rqstp); 53 struct timeval nfssvc_boot; 54 static struct svc_serv *nfsd_serv; 55 static atomic_t nfsd_busy; 56 static unsigned long nfsd_last_call; 57 static DEFINE_SPINLOCK(nfsd_call_lock); 58 59 struct nfsd_list { 60 struct list_head list; 61 struct task_struct *task; 62 }; 63 static struct list_head nfsd_list = LIST_HEAD_INIT(nfsd_list); 64 65 /* 66 * Maximum number of nfsd processes 67 */ 68 #define NFSD_MAXSERVS 8192 69 70 int nfsd_nrthreads(void) 71 { 72 if (nfsd_serv == NULL) 73 return 0; 74 else 75 return nfsd_serv->sv_nrthreads; 76 } 77 78 int 79 nfsd_svc(unsigned short port, int nrservs) 80 { 81 int error; 82 int none_left; 83 struct list_head *victim; 84 85 lock_kernel(); 86 dprintk("nfsd: creating service\n"); 87 error = -EINVAL; 88 if (nrservs <= 0) 89 nrservs = 0; 90 if (nrservs > NFSD_MAXSERVS) 91 nrservs = NFSD_MAXSERVS; 92 93 /* Readahead param cache - will no-op if it already exists */ 94 error = nfsd_racache_init(2*nrservs); 95 if (error<0) 96 goto out; 97 error = nfs4_state_init(); 98 if (error<0) 99 goto out; 100 if (!nfsd_serv) { 101 atomic_set(&nfsd_busy, 0); 102 error = -ENOMEM; 103 nfsd_serv = svc_create(&nfsd_program, NFSD_BUFSIZE); 104 if (nfsd_serv == NULL) 105 goto out; 106 error = svc_makesock(nfsd_serv, IPPROTO_UDP, port); 107 if (error < 0) 108 goto failure; 109 110 #ifdef CONFIG_NFSD_TCP 111 error = svc_makesock(nfsd_serv, IPPROTO_TCP, port); 112 if (error < 0) 113 goto failure; 114 #endif 115 do_gettimeofday(&nfssvc_boot); /* record boot time */ 116 } else 117 nfsd_serv->sv_nrthreads++; 118 nrservs -= (nfsd_serv->sv_nrthreads-1); 119 while (nrservs > 0) { 120 nrservs--; 121 __module_get(THIS_MODULE); 122 error = svc_create_thread(nfsd, nfsd_serv); 123 if (error < 0) { 124 module_put(THIS_MODULE); 125 break; 126 } 127 } 128 victim = nfsd_list.next; 129 while (nrservs < 0 && victim != &nfsd_list) { 130 struct nfsd_list *nl = 131 list_entry(victim,struct nfsd_list, list); 132 victim = victim->next; 133 send_sig(SIG_NOCLEAN, nl->task, 1); 134 nrservs++; 135 } 136 failure: 137 none_left = (nfsd_serv->sv_nrthreads == 1); 138 svc_destroy(nfsd_serv); /* Release server */ 139 if (none_left) { 140 nfsd_serv = NULL; 141 nfsd_racache_shutdown(); 142 nfs4_state_shutdown(); 143 } 144 out: 145 unlock_kernel(); 146 return error; 147 } 148 149 static inline void 150 update_thread_usage(int busy_threads) 151 { 152 unsigned long prev_call; 153 unsigned long diff; 154 int decile; 155 156 spin_lock(&nfsd_call_lock); 157 prev_call = nfsd_last_call; 158 nfsd_last_call = jiffies; 159 decile = busy_threads*10/nfsdstats.th_cnt; 160 if (decile>0 && decile <= 10) { 161 diff = nfsd_last_call - prev_call; 162 if ( (nfsdstats.th_usage[decile-1] += diff) >= NFSD_USAGE_WRAP) 163 nfsdstats.th_usage[decile-1] -= NFSD_USAGE_WRAP; 164 if (decile == 10) 165 nfsdstats.th_fullcnt++; 166 } 167 spin_unlock(&nfsd_call_lock); 168 } 169 170 /* 171 * This is the NFS server kernel thread 172 */ 173 static void 174 nfsd(struct svc_rqst *rqstp) 175 { 176 struct svc_serv *serv = rqstp->rq_server; 177 struct fs_struct *fsp; 178 int err; 179 struct nfsd_list me; 180 sigset_t shutdown_mask, allowed_mask; 181 182 /* Lock module and set up kernel thread */ 183 lock_kernel(); 184 daemonize("nfsd"); 185 186 /* After daemonize() this kernel thread shares current->fs 187 * with the init process. We need to create files with a 188 * umask of 0 instead of init's umask. */ 189 fsp = copy_fs_struct(current->fs); 190 if (!fsp) { 191 printk("Unable to start nfsd thread: out of memory\n"); 192 goto out; 193 } 194 exit_fs(current); 195 current->fs = fsp; 196 current->fs->umask = 0; 197 198 siginitsetinv(&shutdown_mask, SHUTDOWN_SIGS); 199 siginitsetinv(&allowed_mask, ALLOWED_SIGS); 200 201 nfsdstats.th_cnt++; 202 203 lockd_up(); /* start lockd */ 204 205 me.task = current; 206 list_add(&me.list, &nfsd_list); 207 208 unlock_kernel(); 209 210 /* 211 * We want less throttling in balance_dirty_pages() so that nfs to 212 * localhost doesn't cause nfsd to lock up due to all the client's 213 * dirty pages. 214 */ 215 current->flags |= PF_LESS_THROTTLE; 216 217 /* 218 * The main request loop 219 */ 220 for (;;) { 221 /* Block all but the shutdown signals */ 222 sigprocmask(SIG_SETMASK, &shutdown_mask, NULL); 223 224 /* 225 * Find a socket with data available and call its 226 * recvfrom routine. 227 */ 228 while ((err = svc_recv(serv, rqstp, 229 60*60*HZ)) == -EAGAIN) 230 ; 231 if (err < 0) 232 break; 233 update_thread_usage(atomic_read(&nfsd_busy)); 234 atomic_inc(&nfsd_busy); 235 236 /* Lock the export hash tables for reading. */ 237 exp_readlock(); 238 239 /* Process request with signals blocked. */ 240 sigprocmask(SIG_SETMASK, &allowed_mask, NULL); 241 242 svc_process(serv, rqstp); 243 244 /* Unlock export hash tables */ 245 exp_readunlock(); 246 update_thread_usage(atomic_read(&nfsd_busy)); 247 atomic_dec(&nfsd_busy); 248 } 249 250 if (err != -EINTR) { 251 printk(KERN_WARNING "nfsd: terminating on error %d\n", -err); 252 } else { 253 unsigned int signo; 254 255 for (signo = 1; signo <= _NSIG; signo++) 256 if (sigismember(¤t->pending.signal, signo) && 257 !sigismember(¤t->blocked, signo)) 258 break; 259 err = signo; 260 } 261 /* Clear signals before calling lockd_down() and svc_exit_thread() */ 262 flush_signals(current); 263 264 lock_kernel(); 265 266 /* Release lockd */ 267 lockd_down(); 268 269 /* Check if this is last thread */ 270 if (serv->sv_nrthreads==1) { 271 272 printk(KERN_WARNING "nfsd: last server has exited\n"); 273 if (err != SIG_NOCLEAN) { 274 printk(KERN_WARNING "nfsd: unexporting all filesystems\n"); 275 nfsd_export_flush(); 276 } 277 nfsd_serv = NULL; 278 nfsd_racache_shutdown(); /* release read-ahead cache */ 279 nfs4_state_shutdown(); 280 } 281 list_del(&me.list); 282 nfsdstats.th_cnt --; 283 284 out: 285 /* Release the thread */ 286 svc_exit_thread(rqstp); 287 288 /* Release module */ 289 module_put_and_exit(0); 290 } 291 292 int 293 nfsd_dispatch(struct svc_rqst *rqstp, u32 *statp) 294 { 295 struct svc_procedure *proc; 296 kxdrproc_t xdr; 297 u32 nfserr; 298 u32 *nfserrp; 299 300 dprintk("nfsd_dispatch: vers %d proc %d\n", 301 rqstp->rq_vers, rqstp->rq_proc); 302 proc = rqstp->rq_procinfo; 303 304 /* Check whether we have this call in the cache. */ 305 switch (nfsd_cache_lookup(rqstp, proc->pc_cachetype)) { 306 case RC_INTR: 307 case RC_DROPIT: 308 return 0; 309 case RC_REPLY: 310 return 1; 311 case RC_DOIT:; 312 /* do it */ 313 } 314 315 /* Decode arguments */ 316 xdr = proc->pc_decode; 317 if (xdr && !xdr(rqstp, (u32*)rqstp->rq_arg.head[0].iov_base, 318 rqstp->rq_argp)) { 319 dprintk("nfsd: failed to decode arguments!\n"); 320 nfsd_cache_update(rqstp, RC_NOCACHE, NULL); 321 *statp = rpc_garbage_args; 322 return 1; 323 } 324 325 /* need to grab the location to store the status, as 326 * nfsv4 does some encoding while processing 327 */ 328 nfserrp = rqstp->rq_res.head[0].iov_base 329 + rqstp->rq_res.head[0].iov_len; 330 rqstp->rq_res.head[0].iov_len += sizeof(u32); 331 332 /* Now call the procedure handler, and encode NFS status. */ 333 nfserr = proc->pc_func(rqstp, rqstp->rq_argp, rqstp->rq_resp); 334 if (nfserr == nfserr_jukebox && rqstp->rq_vers == 2) 335 nfserr = nfserr_dropit; 336 if (nfserr == nfserr_dropit) { 337 dprintk("nfsd: Dropping request due to malloc failure!\n"); 338 nfsd_cache_update(rqstp, RC_NOCACHE, NULL); 339 return 0; 340 } 341 342 if (rqstp->rq_proc != 0) 343 *nfserrp++ = nfserr; 344 345 /* Encode result. 346 * For NFSv2, additional info is never returned in case of an error. 347 */ 348 if (!(nfserr && rqstp->rq_vers == 2)) { 349 xdr = proc->pc_encode; 350 if (xdr && !xdr(rqstp, nfserrp, 351 rqstp->rq_resp)) { 352 /* Failed to encode result. Release cache entry */ 353 dprintk("nfsd: failed to encode result!\n"); 354 nfsd_cache_update(rqstp, RC_NOCACHE, NULL); 355 *statp = rpc_system_err; 356 return 1; 357 } 358 } 359 360 /* Store reply in cache. */ 361 nfsd_cache_update(rqstp, proc->pc_cachetype, statp + 1); 362 return 1; 363 } 364 365 extern struct svc_version nfsd_version2, nfsd_version3, nfsd_version4; 366 367 static struct svc_version * nfsd_version[] = { 368 [2] = &nfsd_version2, 369 #if defined(CONFIG_NFSD_V3) 370 [3] = &nfsd_version3, 371 #endif 372 #if defined(CONFIG_NFSD_V4) 373 [4] = &nfsd_version4, 374 #endif 375 }; 376 377 #define NFSD_NRVERS (sizeof(nfsd_version)/sizeof(nfsd_version[0])) 378 struct svc_program nfsd_program = { 379 .pg_prog = NFS_PROGRAM, /* program number */ 380 .pg_nvers = NFSD_NRVERS, /* nr of entries in nfsd_version */ 381 .pg_vers = nfsd_version, /* version table */ 382 .pg_name = "nfsd", /* program name */ 383 .pg_class = "nfsd", /* authentication class */ 384 .pg_stats = &nfsd_svcstats, /* version table */ 385 .pg_authenticate = &svc_set_client, /* export authentication */ 386 387 }; 388