fs/nfsd/nfssvc.c

   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/smp_lock.h>
  22 #include <linux/freezer.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 #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
  62 static struct svc_stat  nfsd_acl_svcstats;
  63 static struct svc_version *     nfsd_acl_version[] = {
  64         [2] = &nfsd_acl_version2,
  65         [3] = &nfsd_acl_version3,
  66 };
  67
  68 #define NFSD_ACL_MINVERS            2
  69 #define NFSD_ACL_NRVERS         ARRAY_SIZE(nfsd_acl_version)
  70 static struct svc_version *nfsd_acl_versions[NFSD_ACL_NRVERS];
  71
  72 static struct svc_program       nfsd_acl_program = {
  73         .pg_prog                = NFS_ACL_PROGRAM,
  74         .pg_nvers               = NFSD_ACL_NRVERS,
  75         .pg_vers                = nfsd_acl_versions,
  76         .pg_name                = "nfsacl",
  77         .pg_class               = "nfsd",
  78         .pg_stats               = &nfsd_acl_svcstats,
  79         .pg_authenticate        = &svc_set_client,
  80 };
  81
  82 static struct svc_stat  nfsd_acl_svcstats = {
  83         .program        = &nfsd_acl_program,
  84 };
  85 #endif /* defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL) */
  86
  87 static struct svc_version *     nfsd_version[] = {
  88         [2] = &nfsd_version2,
  89 #if defined(CONFIG_NFSD_V3)
  90         [3] = &nfsd_version3,
  91 #endif
  92 #if defined(CONFIG_NFSD_V4)
  93         [4] = &nfsd_version4,
  94 #endif
  95 };
  96
  97 #define NFSD_MINVERS            2
  98 #define NFSD_NRVERS             ARRAY_SIZE(nfsd_version)
  99 static struct svc_version *nfsd_versions[NFSD_NRVERS];
 100
 101 struct svc_program              nfsd_program = {
 102 #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
 103         .pg_next                = &nfsd_acl_program,
 104 #endif
 105         .pg_prog                = NFS_PROGRAM,          /* program number */
 106         .pg_nvers               = NFSD_NRVERS,          /* nr of entries in nfsd_version */
 107         .pg_vers                = nfsd_versions,        /* version table */
 108         .pg_name                = "nfsd",               /* program name */
 109         .pg_class               = "nfsd",               /* authentication class */
 110         .pg_stats               = &nfsd_svcstats,       /* version table */
 111         .pg_authenticate        = &svc_set_client,      /* export authentication */
 112
 113 };
 114
 115 int nfsd_vers(int vers, enum vers_op change)
 116 {
 117         if (vers < NFSD_MINVERS || vers >= NFSD_NRVERS)
 118                 return -1;
 119         switch(change) {
 120         case NFSD_SET:
 121                 nfsd_versions[vers] = nfsd_version[vers];
 122 #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
 123                 if (vers < NFSD_ACL_NRVERS)
 124                         nfsd_acl_versions[vers] = nfsd_acl_version[vers];
 125 #endif
 126                 break;
 127         case NFSD_CLEAR:
 128                 nfsd_versions[vers] = NULL;
 129 #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
 130                 if (vers < NFSD_ACL_NRVERS)
 131                         nfsd_acl_versions[vers] = NULL;
 132 #endif
 133                 break;
 134         case NFSD_TEST:
 135                 return nfsd_versions[vers] != NULL;
 136         case NFSD_AVAIL:
 137                 return nfsd_version[vers] != NULL;
 138         }
 139         return 0;
 140 }
 141 /*
 142  * Maximum number of nfsd processes
 143  */
 144 #define NFSD_MAXSERVS           8192
 145
 146 int nfsd_nrthreads(void)
 147 {
 148         if (nfsd_serv == NULL)
 149                 return 0;
 150         else
 151                 return nfsd_serv->sv_nrthreads;
 152 }
 153
 154 static int killsig;     /* signal that was used to kill last nfsd */
 155 static void nfsd_last_thread(struct svc_serv *serv)
 156 {
 157         /* When last nfsd thread exits we need to do some clean-up */
 158         struct svc_xprt *xprt;
 159         list_for_each_entry(xprt, &serv->sv_permsocks, xpt_list)
 160                 lockd_down();
 161         nfsd_serv = NULL;
 162         nfsd_racache_shutdown();
 163         nfs4_state_shutdown();
 164
 165         printk(KERN_WARNING "nfsd: last server has exited\n");
 166         if (killsig != SIG_NOCLEAN) {
 167                 printk(KERN_WARNING "nfsd: unexporting all filesystems\n");
 168                 nfsd_export_flush();
 169         }
 170 }
 171
 172 void nfsd_reset_versions(void)
 173 {
 174         int found_one = 0;
 175         int i;
 176
 177         for (i = NFSD_MINVERS; i < NFSD_NRVERS; i++) {
 178                 if (nfsd_program.pg_vers[i])
 179                         found_one = 1;
 180         }
 181
 182         if (!found_one) {
 183                 for (i = NFSD_MINVERS; i < NFSD_NRVERS; i++)
 184                         nfsd_program.pg_vers[i] = nfsd_version[i];
 185 #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
 186                 for (i = NFSD_ACL_MINVERS; i < NFSD_ACL_NRVERS; i++)
 187                         nfsd_acl_program.pg_vers[i] =
 188                                 nfsd_acl_version[i];
 189 #endif
 190         }
 191 }
 192
 193 int nfsd_create_serv(void)
 194 {
 195         int err = 0;
 196         lock_kernel();
 197         if (nfsd_serv) {
 198                 svc_get(nfsd_serv);
 199                 unlock_kernel();
 200                 return 0;
 201         }
 202         if (nfsd_max_blksize == 0) {
 203                 /* choose a suitable default */
 204                 struct sysinfo i;
 205                 si_meminfo(&i);
 206                 /* Aim for 1/4096 of memory per thread
 207                  * This gives 1MB on 4Gig machines
 208                  * But only uses 32K on 128M machines.
 209                  * Bottom out at 8K on 32M and smaller.
 210                  * Of course, this is only a default.
 211                  */
 212                 nfsd_max_blksize = NFSSVC_MAXBLKSIZE;
 213                 i.totalram <<= PAGE_SHIFT - 12;
 214                 while (nfsd_max_blksize > i.totalram &&
 215                        nfsd_max_blksize >= 8*1024*2)
 216                         nfsd_max_blksize /= 2;
 217         }
 218
 219         atomic_set(&nfsd_busy, 0);
 220         nfsd_serv = svc_create_pooled(&nfsd_program,
 221                                       nfsd_max_blksize,
 222                                       nfsd_last_thread,
 223                                       nfsd, SIG_NOCLEAN, THIS_MODULE);
 224         if (nfsd_serv == NULL)
 225                 err = -ENOMEM;
 226         unlock_kernel();
 227         do_gettimeofday(&nfssvc_boot);          /* record boot time */
 228         return err;
 229 }
 230
 231 static int nfsd_init_socks(int port)
 232 {
 233         int error;
 234         if (!list_empty(&nfsd_serv->sv_permsocks))
 235                 return 0;
 236
 237         error = lockd_up(IPPROTO_UDP);
 238         if (error >= 0) {
 239                 error = svc_create_xprt(nfsd_serv, "udp", port,
 240                                         SVC_SOCK_DEFAULTS);
 241                 if (error < 0)
 242                         lockd_down();
 243         }
 244         if (error < 0)
 245                 return error;
 246
 247 #ifdef CONFIG_NFSD_TCP
 248         error = lockd_up(IPPROTO_TCP);
 249         if (error >= 0) {
 250                 error = svc_create_xprt(nfsd_serv, "tcp", port,
 251                                         SVC_SOCK_DEFAULTS);
 252                 if (error < 0)
 253                         lockd_down();
 254         }
 255         if (error < 0)
 256                 return error;
 257 #endif
 258         return 0;
 259 }
 260
 261 int nfsd_nrpools(void)
 262 {
 263         if (nfsd_serv == NULL)
 264                 return 0;
 265         else
 266                 return nfsd_serv->sv_nrpools;
 267 }
 268
 269 int nfsd_get_nrthreads(int n, int *nthreads)
 270 {
 271         int i = 0;
 272
 273         if (nfsd_serv != NULL) {
 274                 for (i = 0; i < nfsd_serv->sv_nrpools && i < n; i++)
 275                         nthreads[i] = nfsd_serv->sv_pools[i].sp_nrthreads;
 276         }
 277
 278         return 0;
 279 }
 280
 281 int nfsd_set_nrthreads(int n, int *nthreads)
 282 {
 283         int i = 0;
 284         int tot = 0;
 285         int err = 0;
 286
 287         if (nfsd_serv == NULL || n <= 0)
 288                 return 0;
 289
 290         if (n > nfsd_serv->sv_nrpools)
 291                 n = nfsd_serv->sv_nrpools;
 292
 293         /* enforce a global maximum number of threads */
 294         tot = 0;
 295         for (i = 0; i < n; i++) {
 296                 if (nthreads[i] > NFSD_MAXSERVS)
 297                         nthreads[i] = NFSD_MAXSERVS;
 298                 tot += nthreads[i];
 299         }
 300         if (tot > NFSD_MAXSERVS) {
 301                 /* total too large: scale down requested numbers */
 302                 for (i = 0; i < n && tot > 0; i++) {
 303                         int new = nthreads[i] * NFSD_MAXSERVS / tot;
 304                         tot -= (nthreads[i] - new);
 305                         nthreads[i] = new;
 306                 }
 307                 for (i = 0; i < n && tot > 0; i++) {
 308                         nthreads[i]--;
 309                         tot--;
 310                 }
 311         }
 312
 313         /*
 314          * There must always be a thread in pool 0; the admin
 315          * can't shut down NFS completely using pool_threads.
 316          */
 317         if (nthreads[0] == 0)
 318                 nthreads[0] = 1;
 319
 320         /* apply the new numbers */
 321         lock_kernel();
 322         svc_get(nfsd_serv);
 323         for (i = 0; i < n; i++) {
 324                 err = svc_set_num_threads(nfsd_serv, &nfsd_serv->sv_pools[i],
 325                                           nthreads[i]);
 326                 if (err)
 327                         break;
 328         }
 329         svc_destroy(nfsd_serv);
 330         unlock_kernel();
 331
 332         return err;
 333 }
 334
 335 int
 336 nfsd_svc(unsigned short port, int nrservs)
 337 {
 338         int     error;
 339
 340         lock_kernel();
 341         dprintk("nfsd: creating service\n");
 342         error = -EINVAL;
 343         if (nrservs <= 0)
 344                 nrservs = 0;
 345         if (nrservs > NFSD_MAXSERVS)
 346                 nrservs = NFSD_MAXSERVS;
 347
 348         /* Readahead param cache - will no-op if it already exists */
 349         error = nfsd_racache_init(2*nrservs);
 350         if (error<0)
 351                 goto out;
 352         nfs4_state_start();
 353
 354         nfsd_reset_versions();
 355
 356         error = nfsd_create_serv();
 357
 358         if (error)
 359                 goto out;
 360         error = nfsd_init_socks(port);
 361         if (error)
 362                 goto failure;
 363
 364         error = svc_set_num_threads(nfsd_serv, NULL, nrservs);
 365  failure:
 366         svc_destroy(nfsd_serv);         /* Release server */
 367  out:
 368         unlock_kernel();
 369         return error;
 370 }
 371
 372 static inline void
 373 update_thread_usage(int busy_threads)
 374 {
 375         unsigned long prev_call;
 376         unsigned long diff;
 377         int decile;
 378
 379         spin_lock(&nfsd_call_lock);
 380         prev_call = nfsd_last_call;
 381         nfsd_last_call = jiffies;
 382         decile = busy_threads*10/nfsdstats.th_cnt;
 383         if (decile>0 && decile <= 10) {
 384                 diff = nfsd_last_call - prev_call;
 385                 if ( (nfsdstats.th_usage[decile-1] += diff) >= NFSD_USAGE_WRAP)
 386                         nfsdstats.th_usage[decile-1] -= NFSD_USAGE_WRAP;
 387                 if (decile == 10)
 388                         nfsdstats.th_fullcnt++;
 389         }
 390         spin_unlock(&nfsd_call_lock);
 391 }
 392
 393 /*
 394  * This is the NFS server kernel thread
 395  */
 396 static void
 397 nfsd(struct svc_rqst *rqstp)
 398 {
 399         struct fs_struct *fsp;
 400         int             err;
 401         sigset_t shutdown_mask, allowed_mask;
 402
 403         /* Lock module and set up kernel thread */
 404         lock_kernel();
 405         daemonize("nfsd");
 406
 407         /* After daemonize() this kernel thread shares current->fs
 408          * with the init process. We need to create files with a
 409          * umask of 0 instead of init's umask. */
 410         fsp = copy_fs_struct(current->fs);
 411         if (!fsp) {
 412                 printk("Unable to start nfsd thread: out of memory\n");
 413                 goto out;
 414         }
 415         exit_fs(current);
 416         current->fs = fsp;
 417         current->fs->umask = 0;
 418
 419         siginitsetinv(&shutdown_mask, SHUTDOWN_SIGS);
 420         siginitsetinv(&allowed_mask, ALLOWED_SIGS);
 421
 422         nfsdstats.th_cnt++;
 423
 424         rqstp->rq_task = current;
 425
 426         unlock_kernel();
 427
 428         /*
 429          * We want less throttling in balance_dirty_pages() so that nfs to
 430          * localhost doesn't cause nfsd to lock up due to all the client's
 431          * dirty pages.
 432          */
 433         current->flags |= PF_LESS_THROTTLE;
 434         set_freezable();
 435
 436         /*
 437          * The main request loop
 438          */
 439         for (;;) {
 440                 /* Block all but the shutdown signals */
 441                 sigprocmask(SIG_SETMASK, &shutdown_mask, NULL);
 442
 443                 /*
 444                  * Find a socket with data available and call its
 445                  * recvfrom routine.
 446                  */
 447                 while ((err = svc_recv(rqstp, 60*60*HZ)) == -EAGAIN)
 448                         ;
 449                 if (err < 0)
 450                         break;
 451                 update_thread_usage(atomic_read(&nfsd_busy));
 452                 atomic_inc(&nfsd_busy);
 453
 454                 /* Lock the export hash tables for reading. */
 455                 exp_readlock();
 456
 457                 /* Process request with signals blocked.  */
 458                 sigprocmask(SIG_SETMASK, &allowed_mask, NULL);
 459
 460                 svc_process(rqstp);
 461
 462                 /* Unlock export hash tables */
 463                 exp_readunlock();
 464                 update_thread_usage(atomic_read(&nfsd_busy));
 465                 atomic_dec(&nfsd_busy);
 466         }
 467
 468         if (err != -EINTR) {
 469                 printk(KERN_WARNING "nfsd: terminating on error %d\n", -err);
 470         } else {
 471                 unsigned int    signo;
 472
 473                 for (signo = 1; signo <= _NSIG; signo++)
 474                         if (sigismember(&current->pending.signal, signo) &&
 475                             !sigismember(&current->blocked, signo))
 476                                 break;
 477                 killsig = signo;
 478         }
 479         /* Clear signals before calling svc_exit_thread() */
 480         flush_signals(current);
 481
 482         lock_kernel();
 483
 484         nfsdstats.th_cnt --;
 485
 486 out:
 487         /* Release the thread */
 488         svc_exit_thread(rqstp);
 489
 490         /* Release module */
 491         unlock_kernel();
 492         module_put_and_exit(0);
 493 }
 494
 495 static __be32 map_new_errors(u32 vers, __be32 nfserr)
 496 {
 497         if (nfserr == nfserr_jukebox && vers == 2)
 498                 return nfserr_dropit;
 499         if (nfserr == nfserr_wrongsec && vers < 4)
 500                 return nfserr_acces;
 501         return nfserr;
 502 }
 503
 504 int
 505 nfsd_dispatch(struct svc_rqst *rqstp, __be32 *statp)
 506 {
 507         struct svc_procedure    *proc;
 508         kxdrproc_t              xdr;
 509         __be32                  nfserr;
 510         __be32                  *nfserrp;
 511
 512         dprintk("nfsd_dispatch: vers %d proc %d\n",
 513                                 rqstp->rq_vers, rqstp->rq_proc);
 514         proc = rqstp->rq_procinfo;
 515
 516         /* Check whether we have this call in the cache. */
 517         switch (nfsd_cache_lookup(rqstp, proc->pc_cachetype)) {
 518         case RC_INTR:
 519         case RC_DROPIT:
 520                 return 0;
 521         case RC_REPLY:
 522                 return 1;
 523         case RC_DOIT:;
 524                 /* do it */
 525         }
 526
 527         /* Decode arguments */
 528         xdr = proc->pc_decode;
 529         if (xdr && !xdr(rqstp, (__be32*)rqstp->rq_arg.head[0].iov_base,
 530                         rqstp->rq_argp)) {
 531                 dprintk("nfsd: failed to decode arguments!\n");
 532                 nfsd_cache_update(rqstp, RC_NOCACHE, NULL);
 533                 *statp = rpc_garbage_args;
 534                 return 1;
 535         }
 536
 537         /* need to grab the location to store the status, as
 538          * nfsv4 does some encoding while processing
 539          */
 540         nfserrp = rqstp->rq_res.head[0].iov_base
 541                 + rqstp->rq_res.head[0].iov_len;
 542         rqstp->rq_res.head[0].iov_len += sizeof(__be32);
 543
 544         /* Now call the procedure handler, and encode NFS status. */
 545         nfserr = proc->pc_func(rqstp, rqstp->rq_argp, rqstp->rq_resp);
 546         nfserr = map_new_errors(rqstp->rq_vers, nfserr);
 547         if (nfserr == nfserr_dropit) {
 548                 dprintk("nfsd: Dropping request; may be revisited later\n");
 549                 nfsd_cache_update(rqstp, RC_NOCACHE, NULL);
 550                 return 0;
 551         }
 552
 553         if (rqstp->rq_proc != 0)
 554                 *nfserrp++ = nfserr;
 555
 556         /* Encode result.
 557          * For NFSv2, additional info is never returned in case of an error.
 558          */
 559         if (!(nfserr && rqstp->rq_vers == 2)) {
 560                 xdr = proc->pc_encode;
 561                 if (xdr && !xdr(rqstp, nfserrp,
 562                                 rqstp->rq_resp)) {
 563                         /* Failed to encode result. Release cache entry */
 564                         dprintk("nfsd: failed to encode result!\n");
 565                         nfsd_cache_update(rqstp, RC_NOCACHE, NULL);
 566                         *statp = rpc_system_err;
 567                         return 1;
 568                 }
 569         }
 570
 571         /* Store reply in cache. */
 572         nfsd_cache_update(rqstp, proc->pc_cachetype, statp + 1);
 573         return 1;
 574 }