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         error = lockd_up(IPPROTO_TCP);
 248         if (error >= 0) {
 249                 error = svc_create_xprt(nfsd_serv, "tcp", port,
 250                                         SVC_SOCK_DEFAULTS);
 251                 if (error < 0)
 252                         lockd_down();
 253         }
 254         if (error < 0)
 255                 return error;
 256         return 0;
 257 }
 258
 259 int nfsd_nrpools(void)
 260 {
 261         if (nfsd_serv == NULL)
 262                 return 0;
 263         else
 264                 return nfsd_serv->sv_nrpools;
 265 }
 266
 267 int nfsd_get_nrthreads(int n, int *nthreads)
 268 {
 269         int i = 0;
 270
 271         if (nfsd_serv != NULL) {
 272                 for (i = 0; i < nfsd_serv->sv_nrpools && i < n; i++)
 273                         nthreads[i] = nfsd_serv->sv_pools[i].sp_nrthreads;
 274         }
 275
 276         return 0;
 277 }
 278
 279 int nfsd_set_nrthreads(int n, int *nthreads)
 280 {
 281         int i = 0;
 282         int tot = 0;
 283         int err = 0;
 284
 285         if (nfsd_serv == NULL || n <= 0)
 286                 return 0;
 287
 288         if (n > nfsd_serv->sv_nrpools)
 289                 n = nfsd_serv->sv_nrpools;
 290
 291         /* enforce a global maximum number of threads */
 292         tot = 0;
 293         for (i = 0; i < n; i++) {
 294                 if (nthreads[i] > NFSD_MAXSERVS)
 295                         nthreads[i] = NFSD_MAXSERVS;
 296                 tot += nthreads[i];
 297         }
 298         if (tot > NFSD_MAXSERVS) {
 299                 /* total too large: scale down requested numbers */
 300                 for (i = 0; i < n && tot > 0; i++) {
 301                         int new = nthreads[i] * NFSD_MAXSERVS / tot;
 302                         tot -= (nthreads[i] - new);
 303                         nthreads[i] = new;
 304                 }
 305                 for (i = 0; i < n && tot > 0; i++) {
 306                         nthreads[i]--;
 307                         tot--;
 308                 }
 309         }
 310
 311         /*
 312          * There must always be a thread in pool 0; the admin
 313          * can't shut down NFS completely using pool_threads.
 314          */
 315         if (nthreads[0] == 0)
 316                 nthreads[0] = 1;
 317
 318         /* apply the new numbers */
 319         lock_kernel();
 320         svc_get(nfsd_serv);
 321         for (i = 0; i < n; i++) {
 322                 err = svc_set_num_threads(nfsd_serv, &nfsd_serv->sv_pools[i],
 323                                           nthreads[i]);
 324                 if (err)
 325                         break;
 326         }
 327         svc_destroy(nfsd_serv);
 328         unlock_kernel();
 329
 330         return err;
 331 }
 332
 333 int
 334 nfsd_svc(unsigned short port, int nrservs)
 335 {
 336         int     error;
 337
 338         lock_kernel();
 339         dprintk("nfsd: creating service\n");
 340         error = -EINVAL;
 341         if (nrservs <= 0)
 342                 nrservs = 0;
 343         if (nrservs > NFSD_MAXSERVS)
 344                 nrservs = NFSD_MAXSERVS;
 345
 346         /* Readahead param cache - will no-op if it already exists */
 347         error = nfsd_racache_init(2*nrservs);
 348         if (error<0)
 349                 goto out;
 350         nfs4_state_start();
 351
 352         nfsd_reset_versions();
 353
 354         error = nfsd_create_serv();
 355
 356         if (error)
 357                 goto out;
 358         error = nfsd_init_socks(port);
 359         if (error)
 360                 goto failure;
 361
 362         error = svc_set_num_threads(nfsd_serv, NULL, nrservs);
 363  failure:
 364         svc_destroy(nfsd_serv);         /* Release server */
 365  out:
 366         unlock_kernel();
 367         return error;
 368 }
 369
 370 static inline void
 371 update_thread_usage(int busy_threads)
 372 {
 373         unsigned long prev_call;
 374         unsigned long diff;
 375         int decile;
 376
 377         spin_lock(&nfsd_call_lock);
 378         prev_call = nfsd_last_call;
 379         nfsd_last_call = jiffies;
 380         decile = busy_threads*10/nfsdstats.th_cnt;
 381         if (decile>0 && decile <= 10) {
 382                 diff = nfsd_last_call - prev_call;
 383                 if ( (nfsdstats.th_usage[decile-1] += diff) >= NFSD_USAGE_WRAP)
 384                         nfsdstats.th_usage[decile-1] -= NFSD_USAGE_WRAP;
 385                 if (decile == 10)
 386                         nfsdstats.th_fullcnt++;
 387         }
 388         spin_unlock(&nfsd_call_lock);
 389 }
 390
 391 /*
 392  * This is the NFS server kernel thread
 393  */
 394 static void
 395 nfsd(struct svc_rqst *rqstp)
 396 {
 397         struct fs_struct *fsp;
 398         int             err;
 399         sigset_t shutdown_mask, allowed_mask;
 400
 401         /* Lock module and set up kernel thread */
 402         lock_kernel();
 403         daemonize("nfsd");
 404
 405         /* After daemonize() this kernel thread shares current->fs
 406          * with the init process. We need to create files with a
 407          * umask of 0 instead of init's umask. */
 408         fsp = copy_fs_struct(current->fs);
 409         if (!fsp) {
 410                 printk("Unable to start nfsd thread: out of memory\n");
 411                 goto out;
 412         }
 413         exit_fs(current);
 414         current->fs = fsp;
 415         current->fs->umask = 0;
 416
 417         siginitsetinv(&shutdown_mask, SHUTDOWN_SIGS);
 418         siginitsetinv(&allowed_mask, ALLOWED_SIGS);
 419
 420         nfsdstats.th_cnt++;
 421
 422         rqstp->rq_task = current;
 423
 424         unlock_kernel();
 425
 426         /*
 427          * We want less throttling in balance_dirty_pages() so that nfs to
 428          * localhost doesn't cause nfsd to lock up due to all the client's
 429          * dirty pages.
 430          */
 431         current->flags |= PF_LESS_THROTTLE;
 432         set_freezable();
 433
 434         /*
 435          * The main request loop
 436          */
 437         for (;;) {
 438                 /* Block all but the shutdown signals */
 439                 sigprocmask(SIG_SETMASK, &shutdown_mask, NULL);
 440
 441                 /*
 442                  * Find a socket with data available and call its
 443                  * recvfrom routine.
 444                  */
 445                 while ((err = svc_recv(rqstp, 60*60*HZ)) == -EAGAIN)
 446                         ;
 447                 if (err < 0)
 448                         break;
 449                 update_thread_usage(atomic_read(&nfsd_busy));
 450                 atomic_inc(&nfsd_busy);
 451
 452                 /* Lock the export hash tables for reading. */
 453                 exp_readlock();
 454
 455                 /* Process request with signals blocked.  */
 456                 sigprocmask(SIG_SETMASK, &allowed_mask, NULL);
 457
 458                 svc_process(rqstp);
 459
 460                 /* Unlock export hash tables */
 461                 exp_readunlock();
 462                 update_thread_usage(atomic_read(&nfsd_busy));
 463                 atomic_dec(&nfsd_busy);
 464         }
 465
 466         if (err != -EINTR) {
 467                 printk(KERN_WARNING "nfsd: terminating on error %d\n", -err);
 468         } else {
 469                 unsigned int    signo;
 470
 471                 for (signo = 1; signo <= _NSIG; signo++)
 472                         if (sigismember(&current->pending.signal, signo) &&
 473                             !sigismember(&current->blocked, signo))
 474                                 break;
 475                 killsig = signo;
 476         }
 477         /* Clear signals before calling svc_exit_thread() */
 478         flush_signals(current);
 479
 480         lock_kernel();
 481
 482         nfsdstats.th_cnt --;
 483
 484 out:
 485         /* Release the thread */
 486         svc_exit_thread(rqstp);
 487
 488         /* Release module */
 489         unlock_kernel();
 490         module_put_and_exit(0);
 491 }
 492
 493 static __be32 map_new_errors(u32 vers, __be32 nfserr)
 494 {
 495         if (nfserr == nfserr_jukebox && vers == 2)
 496                 return nfserr_dropit;
 497         if (nfserr == nfserr_wrongsec && vers < 4)
 498                 return nfserr_acces;
 499         return nfserr;
 500 }
 501
 502 int
 503 nfsd_dispatch(struct svc_rqst *rqstp, __be32 *statp)
 504 {
 505         struct svc_procedure    *proc;
 506         kxdrproc_t              xdr;
 507         __be32                  nfserr;
 508         __be32                  *nfserrp;
 509
 510         dprintk("nfsd_dispatch: vers %d proc %d\n",
 511                                 rqstp->rq_vers, rqstp->rq_proc);
 512         proc = rqstp->rq_procinfo;
 513
 514         /* Check whether we have this call in the cache. */
 515         switch (nfsd_cache_lookup(rqstp, proc->pc_cachetype)) {
 516         case RC_INTR:
 517         case RC_DROPIT:
 518                 return 0;
 519         case RC_REPLY:
 520                 return 1;
 521         case RC_DOIT:;
 522                 /* do it */
 523         }
 524
 525         /* Decode arguments */
 526         xdr = proc->pc_decode;
 527         if (xdr && !xdr(rqstp, (__be32*)rqstp->rq_arg.head[0].iov_base,
 528                         rqstp->rq_argp)) {
 529                 dprintk("nfsd: failed to decode arguments!\n");
 530                 nfsd_cache_update(rqstp, RC_NOCACHE, NULL);
 531                 *statp = rpc_garbage_args;
 532                 return 1;
 533         }
 534
 535         /* need to grab the location to store the status, as
 536          * nfsv4 does some encoding while processing
 537          */
 538         nfserrp = rqstp->rq_res.head[0].iov_base
 539                 + rqstp->rq_res.head[0].iov_len;
 540         rqstp->rq_res.head[0].iov_len += sizeof(__be32);
 541
 542         /* Now call the procedure handler, and encode NFS status. */
 543         nfserr = proc->pc_func(rqstp, rqstp->rq_argp, rqstp->rq_resp);
 544         nfserr = map_new_errors(rqstp->rq_vers, nfserr);
 545         if (nfserr == nfserr_dropit) {
 546                 dprintk("nfsd: Dropping request; may be revisited later\n");
 547                 nfsd_cache_update(rqstp, RC_NOCACHE, NULL);
 548                 return 0;
 549         }
 550
 551         if (rqstp->rq_proc != 0)
 552                 *nfserrp++ = nfserr;
 553
 554         /* Encode result.
 555          * For NFSv2, additional info is never returned in case of an error.
 556          */
 557         if (!(nfserr && rqstp->rq_vers == 2)) {
 558                 xdr = proc->pc_encode;
 559                 if (xdr && !xdr(rqstp, nfserrp,
 560                                 rqstp->rq_resp)) {
 561                         /* Failed to encode result. Release cache entry */
 562                         dprintk("nfsd: failed to encode result!\n");
 563                         nfsd_cache_update(rqstp, RC_NOCACHE, NULL);
 564                         *statp = rpc_system_err;
 565                         return 1;
 566                 }
 567         }
 568
 569         /* Store reply in cache. */
 570         nfsd_cache_update(rqstp, proc->pc_cachetype, statp + 1);
 571         return 1;
 572 }