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
  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/fs_struct.h>
  23
  24 #include <linux/sunrpc/types.h>
  25 #include <linux/sunrpc/stats.h>
  26 #include <linux/sunrpc/svc.h>
  27 #include <linux/sunrpc/svcsock.h>
  28 #include <linux/sunrpc/cache.h>
  29 #include <linux/nfsd/nfsd.h>
  30 #include <linux/nfsd/stats.h>
  31 #include <linux/nfsd/cache.h>
  32 #include <linux/nfsd/syscall.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        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 #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
  61 static struct svc_stat  nfsd_acl_svcstats;
  62 static struct svc_version *     nfsd_acl_version[] = {
  63         [2] = &nfsd_acl_version2,
  64         [3] = &nfsd_acl_version3,
  65 };
  66
  67 #define NFSD_ACL_MINVERS            2
  68 #define NFSD_ACL_NRVERS         ARRAY_SIZE(nfsd_acl_version)
  69 static struct svc_version *nfsd_acl_versions[NFSD_ACL_NRVERS];
  70
  71 static struct svc_program       nfsd_acl_program = {
  72         .pg_prog                = NFS_ACL_PROGRAM,
  73         .pg_nvers               = NFSD_ACL_NRVERS,
  74         .pg_vers                = nfsd_acl_versions,
  75         .pg_name                = "nfsd",
  76         .pg_class               = "nfsd",
  77         .pg_stats               = &nfsd_acl_svcstats,
  78         .pg_authenticate        = &svc_set_client,
  79 };
  80
  81 static struct svc_stat  nfsd_acl_svcstats = {
  82         .program        = &nfsd_acl_program,
  83 };
  84 #endif /* defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL) */
  85
  86 static struct svc_version *     nfsd_version[] = {
  87         [2] = &nfsd_version2,
  88 #if defined(CONFIG_NFSD_V3)
  89         [3] = &nfsd_version3,
  90 #endif
  91 #if defined(CONFIG_NFSD_V4)
  92         [4] = &nfsd_version4,
  93 #endif
  94 };
  95
  96 #define NFSD_MINVERS            2
  97 #define NFSD_NRVERS             ARRAY_SIZE(nfsd_version)
  98 static struct svc_version *nfsd_versions[NFSD_NRVERS];
  99
 100 struct svc_program              nfsd_program = {
 101 #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
 102         .pg_next                = &nfsd_acl_program,
 103 #endif
 104         .pg_prog                = NFS_PROGRAM,          /* program number */
 105         .pg_nvers               = NFSD_NRVERS,          /* nr of entries in nfsd_version */
 106         .pg_vers                = nfsd_versions,        /* version table */
 107         .pg_name                = "nfsd",               /* program name */
 108         .pg_class               = "nfsd",               /* authentication class */
 109         .pg_stats               = &nfsd_svcstats,       /* version table */
 110         .pg_authenticate        = &svc_set_client,      /* export authentication */
 111
 112 };
 113
 114 int nfsd_vers(int vers, enum vers_op change)
 115 {
 116         if (vers < NFSD_MINVERS || vers >= NFSD_NRVERS)
 117                 return -1;
 118         switch(change) {
 119         case NFSD_SET:
 120                 nfsd_versions[vers] = nfsd_version[vers];
 121                 break;
 122 #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
 123                 if (vers < NFSD_ACL_NRVERS)
 124                         nfsd_acl_version[vers] = nfsd_acl_version[vers];
 125 #endif
 126         case NFSD_CLEAR:
 127                 nfsd_versions[vers] = NULL;
 128 #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
 129                 if (vers < NFSD_ACL_NRVERS)
 130                         nfsd_acl_version[vers] = NULL;
 131 #endif
 132                 break;
 133         case NFSD_TEST:
 134                 return nfsd_versions[vers] != NULL;
 135         case NFSD_AVAIL:
 136                 return nfsd_version[vers] != NULL;
 137         }
 138         return 0;
 139 }
 140 /*
 141  * Maximum number of nfsd processes
 142  */
 143 #define NFSD_MAXSERVS           8192
 144
 145 int nfsd_nrthreads(void)
 146 {
 147         if (nfsd_serv == NULL)
 148                 return 0;
 149         else
 150                 return nfsd_serv->sv_nrthreads;
 151 }
 152
 153 static int killsig;     /* signal that was used to kill last nfsd */
 154 static void nfsd_last_thread(struct svc_serv *serv)
 155 {
 156         /* When last nfsd thread exits we need to do some clean-up */
 157         struct svc_sock *svsk;
 158         list_for_each_entry(svsk, &serv->sv_permsocks, sk_list)
 159                 lockd_down();
 160         nfsd_serv = NULL;
 161         nfsd_racache_shutdown();
 162         nfs4_state_shutdown();
 163
 164         printk(KERN_WARNING "nfsd: last server has exited\n");
 165         if (killsig != SIG_NOCLEAN) {
 166                 printk(KERN_WARNING "nfsd: unexporting all filesystems\n");
 167                 nfsd_export_flush();
 168         }
 169 }
 170
 171 void nfsd_reset_versions(void)
 172 {
 173         int found_one = 0;
 174         int i;
 175
 176         for (i = NFSD_MINVERS; i < NFSD_NRVERS; i++) {
 177                 if (nfsd_program.pg_vers[i])
 178                         found_one = 1;
 179         }
 180
 181         if (!found_one) {
 182                 for (i = NFSD_MINVERS; i < NFSD_NRVERS; i++)
 183                         nfsd_program.pg_vers[i] = nfsd_version[i];
 184 #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
 185                 for (i = NFSD_ACL_MINVERS; i < NFSD_ACL_NRVERS; i++)
 186                         nfsd_acl_program.pg_vers[i] =
 187                                 nfsd_acl_version[i];
 188 #endif
 189         }
 190 }
 191
 192 int nfsd_create_serv(void)
 193 {
 194         int err = 0;
 195         lock_kernel();
 196         if (nfsd_serv) {
 197                 svc_get(nfsd_serv);
 198                 unlock_kernel();
 199                 return 0;
 200         }
 201         if (nfsd_max_blksize == 0) {
 202                 /* choose a suitable default */
 203                 struct sysinfo i;
 204                 si_meminfo(&i);
 205                 /* Aim for 1/4096 of memory per thread
 206                  * This gives 1MB on 4Gig machines
 207                  * But only uses 32K on 128M machines.
 208                  * Bottom out at 8K on 32M and smaller.
 209                  * Of course, this is only a default.
 210                  */
 211                 nfsd_max_blksize = NFSSVC_MAXBLKSIZE;
 212                 i.totalram <<= PAGE_SHIFT - 12;
 213                 while (nfsd_max_blksize > i.totalram &&
 214                        nfsd_max_blksize >= 8*1024*2)
 215                         nfsd_max_blksize /= 2;
 216         }
 217
 218         atomic_set(&nfsd_busy, 0);
 219         nfsd_serv = svc_create_pooled(&nfsd_program,
 220                                       nfsd_max_blksize,
 221                                       nfsd_last_thread,
 222                                       nfsd, SIG_NOCLEAN, THIS_MODULE);
 223         if (nfsd_serv == NULL)
 224                 err = -ENOMEM;
 225         unlock_kernel();
 226         do_gettimeofday(&nfssvc_boot);          /* record boot time */
 227         return err;
 228 }
 229
 230 static int nfsd_init_socks(int port)
 231 {
 232         int error;
 233         if (!list_empty(&nfsd_serv->sv_permsocks))
 234                 return 0;
 235
 236         error = lockd_up(IPPROTO_UDP);
 237         if (error >= 0) {
 238                 error = svc_makesock(nfsd_serv, IPPROTO_UDP, port);
 239                 if (error < 0)
 240                         lockd_down();
 241         }
 242         if (error < 0)
 243                 return error;
 244
 245 #ifdef CONFIG_NFSD_TCP
 246         error = lockd_up(IPPROTO_TCP);
 247         if (error >= 0) {
 248                 error = svc_makesock(nfsd_serv, IPPROTO_TCP, port);
 249                 if (error < 0)
 250                         lockd_down();
 251         }
 252         if (error < 0)
 253                 return error;
 254 #endif
 255         return 0;
 256 }
 257
 258 int nfsd_nrpools(void)
 259 {
 260         if (nfsd_serv == NULL)
 261                 return 0;
 262         else
 263                 return nfsd_serv->sv_nrpools;
 264 }
 265
 266 int nfsd_get_nrthreads(int n, int *nthreads)
 267 {
 268         int i = 0;
 269
 270         if (nfsd_serv != NULL) {
 271                 for (i = 0; i < nfsd_serv->sv_nrpools && i < n; i++)
 272                         nthreads[i] = nfsd_serv->sv_pools[i].sp_nrthreads;
 273         }
 274
 275         return 0;
 276 }
 277
 278 int nfsd_set_nrthreads(int n, int *nthreads)
 279 {
 280         int i = 0;
 281         int tot = 0;
 282         int err = 0;
 283
 284         if (nfsd_serv == NULL || n <= 0)
 285                 return 0;
 286
 287         if (n > nfsd_serv->sv_nrpools)
 288                 n = nfsd_serv->sv_nrpools;
 289
 290         /* enforce a global maximum number of threads */
 291         tot = 0;
 292         for (i = 0; i < n; i++) {
 293                 if (nthreads[i] > NFSD_MAXSERVS)
 294                         nthreads[i] = NFSD_MAXSERVS;
 295                 tot += nthreads[i];
 296         }
 297         if (tot > NFSD_MAXSERVS) {
 298                 /* total too large: scale down requested numbers */
 299                 for (i = 0; i < n && tot > 0; i++) {
 300                         int new = nthreads[i] * NFSD_MAXSERVS / tot;
 301                         tot -= (nthreads[i] - new);
 302                         nthreads[i] = new;
 303                 }
 304                 for (i = 0; i < n && tot > 0; i++) {
 305                         nthreads[i]--;
 306                         tot--;
 307                 }
 308         }
 309
 310         /*
 311          * There must always be a thread in pool 0; the admin
 312          * can't shut down NFS completely using pool_threads.
 313          */
 314         if (nthreads[0] == 0)
 315                 nthreads[0] = 1;
 316
 317         /* apply the new numbers */
 318         lock_kernel();
 319         svc_get(nfsd_serv);
 320         for (i = 0; i < n; i++) {
 321                 err = svc_set_num_threads(nfsd_serv, &nfsd_serv->sv_pools[i],
 322                                           nthreads[i]);
 323                 if (err)
 324                         break;
 325         }
 326         svc_destroy(nfsd_serv);
 327         unlock_kernel();
 328
 329         return err;
 330 }
 331
 332 int
 333 nfsd_svc(unsigned short port, int nrservs)
 334 {
 335         int     error;
 336
 337         lock_kernel();
 338         dprintk("nfsd: creating service\n");
 339         error = -EINVAL;
 340         if (nrservs <= 0)
 341                 nrservs = 0;
 342         if (nrservs > NFSD_MAXSERVS)
 343                 nrservs = NFSD_MAXSERVS;
 344
 345         /* Readahead param cache - will no-op if it already exists */
 346         error = nfsd_racache_init(2*nrservs);
 347         if (error<0)
 348                 goto out;
 349         error = nfs4_state_start();
 350         if (error<0)
 351                 goto out;
 352
 353         nfsd_reset_versions();
 354
 355         error = nfsd_create_serv();
 356
 357         if (error)
 358                 goto out;
 359         error = nfsd_init_socks(port);
 360         if (error)
 361                 goto failure;
 362
 363         error = svc_set_num_threads(nfsd_serv, NULL, nrservs);
 364  failure:
 365         svc_destroy(nfsd_serv);         /* Release server */
 366  out:
 367         unlock_kernel();
 368         return error;
 369 }
 370
 371 static inline void
 372 update_thread_usage(int busy_threads)
 373 {
 374         unsigned long prev_call;
 375         unsigned long diff;
 376         int decile;
 377
 378         spin_lock(&nfsd_call_lock);
 379         prev_call = nfsd_last_call;
 380         nfsd_last_call = jiffies;
 381         decile = busy_threads*10/nfsdstats.th_cnt;
 382         if (decile>0 && decile <= 10) {
 383                 diff = nfsd_last_call - prev_call;
 384                 if ( (nfsdstats.th_usage[decile-1] += diff) >= NFSD_USAGE_WRAP)
 385                         nfsdstats.th_usage[decile-1] -= NFSD_USAGE_WRAP;
 386                 if (decile == 10)
 387                         nfsdstats.th_fullcnt++;
 388         }
 389         spin_unlock(&nfsd_call_lock);
 390 }
 391
 392 /*
 393  * This is the NFS server kernel thread
 394  */
 395 static void
 396 nfsd(struct svc_rqst *rqstp)
 397 {
 398         struct fs_struct *fsp;
 399         int             err;
 400         sigset_t shutdown_mask, allowed_mask;
 401
 402         /* Lock module and set up kernel thread */
 403         lock_kernel();
 404         daemonize("nfsd");
 405
 406         /* After daemonize() this kernel thread shares current->fs
 407          * with the init process. We need to create files with a
 408          * umask of 0 instead of init's umask. */
 409         fsp = copy_fs_struct(current->fs);
 410         if (!fsp) {
 411                 printk("Unable to start nfsd thread: out of memory\n");
 412                 goto out;
 413         }
 414         exit_fs(current);
 415         current->fs = fsp;
 416         current->fs->umask = 0;
 417
 418         siginitsetinv(&shutdown_mask, SHUTDOWN_SIGS);
 419         siginitsetinv(&allowed_mask, ALLOWED_SIGS);
 420
 421         nfsdstats.th_cnt++;
 422
 423         rqstp->rq_task = current;
 424
 425         unlock_kernel();
 426
 427         /*
 428          * We want less throttling in balance_dirty_pages() so that nfs to
 429          * localhost doesn't cause nfsd to lock up due to all the client's
 430          * dirty pages.
 431          */
 432         current->flags |= PF_LESS_THROTTLE;
 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 int
 494 nfsd_dispatch(struct svc_rqst *rqstp, __be32 *statp)
 495 {
 496         struct svc_procedure    *proc;
 497         kxdrproc_t              xdr;
 498         __be32                  nfserr;
 499         __be32                  *nfserrp;
 500
 501         dprintk("nfsd_dispatch: vers %d proc %d\n",
 502                                 rqstp->rq_vers, rqstp->rq_proc);
 503         proc = rqstp->rq_procinfo;
 504
 505         /* Check whether we have this call in the cache. */
 506         switch (nfsd_cache_lookup(rqstp, proc->pc_cachetype)) {
 507         case RC_INTR:
 508         case RC_DROPIT:
 509                 return 0;
 510         case RC_REPLY:
 511                 return 1;
 512         case RC_DOIT:;
 513                 /* do it */
 514         }
 515
 516         /* Decode arguments */
 517         xdr = proc->pc_decode;
 518         if (xdr && !xdr(rqstp, (__be32*)rqstp->rq_arg.head[0].iov_base,
 519                         rqstp->rq_argp)) {
 520                 dprintk("nfsd: failed to decode arguments!\n");
 521                 nfsd_cache_update(rqstp, RC_NOCACHE, NULL);
 522                 *statp = rpc_garbage_args;
 523                 return 1;
 524         }
 525
 526         /* need to grab the location to store the status, as
 527          * nfsv4 does some encoding while processing
 528          */
 529         nfserrp = rqstp->rq_res.head[0].iov_base
 530                 + rqstp->rq_res.head[0].iov_len;
 531         rqstp->rq_res.head[0].iov_len += sizeof(__be32);
 532
 533         /* Now call the procedure handler, and encode NFS status. */
 534         nfserr = proc->pc_func(rqstp, rqstp->rq_argp, rqstp->rq_resp);
 535         if (nfserr == nfserr_jukebox && rqstp->rq_vers == 2)
 536                 nfserr = nfserr_dropit;
 537         if (nfserr == nfserr_dropit) {
 538                 dprintk("nfsd: Dropping request due to malloc failure!\n");
 539                 nfsd_cache_update(rqstp, RC_NOCACHE, NULL);
 540                 return 0;
 541         }
 542
 543         if (rqstp->rq_proc != 0)
 544                 *nfserrp++ = nfserr;
 545
 546         /* Encode result.
 547          * For NFSv2, additional info is never returned in case of an error.
 548          */
 549         if (!(nfserr && rqstp->rq_vers == 2)) {
 550                 xdr = proc->pc_encode;
 551                 if (xdr && !xdr(rqstp, nfserrp,
 552                                 rqstp->rq_resp)) {
 553                         /* Failed to encode result. Release cache entry */
 554                         dprintk("nfsd: failed to encode result!\n");
 555                         nfsd_cache_update(rqstp, RC_NOCACHE, NULL);
 556                         *statp = rpc_system_err;
 557                         return 1;
 558                 }
 559         }
 560
 561         /* Store reply in cache. */
 562         nfsd_cache_update(rqstp, proc->pc_cachetype, statp + 1);
 563         return 1;
 564 }