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/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/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 struct nfsd_list {
  62         struct list_head        list;
  63         struct task_struct      *task;
  64 };
  65 static struct list_head nfsd_list = LIST_HEAD_INIT(nfsd_list);
  66
  67 #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
  68 static struct svc_stat  nfsd_acl_svcstats;
  69 static struct svc_version *     nfsd_acl_version[] = {
  70         [2] = &nfsd_acl_version2,
  71         [3] = &nfsd_acl_version3,
  72 };
  73
  74 #define NFSD_ACL_MINVERS            2
  75 #define NFSD_ACL_NRVERS         ARRAY_SIZE(nfsd_acl_version)
  76 static struct svc_version *nfsd_acl_versions[NFSD_ACL_NRVERS];
  77
  78 static struct svc_program       nfsd_acl_program = {
  79         .pg_prog                = NFS_ACL_PROGRAM,
  80         .pg_nvers               = NFSD_ACL_NRVERS,
  81         .pg_vers                = nfsd_acl_versions,
  82         .pg_name                = "nfsd",
  83         .pg_class               = "nfsd",
  84         .pg_stats               = &nfsd_acl_svcstats,
  85         .pg_authenticate        = &svc_set_client,
  86 };
  87
  88 static struct svc_stat  nfsd_acl_svcstats = {
  89         .program        = &nfsd_acl_program,
  90 };
  91 #endif /* defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL) */
  92
  93 static struct svc_version *     nfsd_version[] = {
  94         [2] = &nfsd_version2,
  95 #if defined(CONFIG_NFSD_V3)
  96         [3] = &nfsd_version3,
  97 #endif
  98 #if defined(CONFIG_NFSD_V4)
  99         [4] = &nfsd_version4,
 100 #endif
 101 };
 102
 103 #define NFSD_MINVERS            2
 104 #define NFSD_NRVERS             ARRAY_SIZE(nfsd_version)
 105 static struct svc_version *nfsd_versions[NFSD_NRVERS];
 106
 107 struct svc_program              nfsd_program = {
 108 #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
 109         .pg_next                = &nfsd_acl_program,
 110 #endif
 111         .pg_prog                = NFS_PROGRAM,          /* program number */
 112         .pg_nvers               = NFSD_NRVERS,          /* nr of entries in nfsd_version */
 113         .pg_vers                = nfsd_versions,        /* version table */
 114         .pg_name                = "nfsd",               /* program name */
 115         .pg_class               = "nfsd",               /* authentication class */
 116         .pg_stats               = &nfsd_svcstats,       /* version table */
 117         .pg_authenticate        = &svc_set_client,      /* export authentication */
 118
 119 };
 120
 121 /*
 122  * Maximum number of nfsd processes
 123  */
 124 #define NFSD_MAXSERVS           8192
 125
 126 int nfsd_nrthreads(void)
 127 {
 128         if (nfsd_serv == NULL)
 129                 return 0;
 130         else
 131                 return nfsd_serv->sv_nrthreads;
 132 }
 133
 134 int
 135 nfsd_svc(unsigned short port, int nrservs)
 136 {
 137         int     error;
 138         int     none_left, found_one, i;
 139         struct list_head *victim;
 140
 141         lock_kernel();
 142         dprintk("nfsd: creating service: vers 0x%x\n",
 143                 nfsd_versbits);
 144         error = -EINVAL;
 145         if (nrservs <= 0)
 146                 nrservs = 0;
 147         if (nrservs > NFSD_MAXSERVS)
 148                 nrservs = NFSD_MAXSERVS;
 149
 150         /* Readahead param cache - will no-op if it already exists */
 151         error = nfsd_racache_init(2*nrservs);
 152         if (error<0)
 153                 goto out;
 154         error = nfs4_state_start();
 155         if (error<0)
 156                 goto out;
 157         if (!nfsd_serv) {
 158                 /*
 159                  * Use the nfsd_ctlbits to define which
 160                  * versions that will be advertised.
 161                  * If nfsd_ctlbits doesn't list any version,
 162                  * export them all.
 163                  */
 164                 found_one = 0;
 165
 166                 for (i = NFSD_MINVERS; i < NFSD_NRVERS; i++) {
 167                         if (NFSCTL_VERISSET(nfsd_versbits, i)) {
 168                                 nfsd_program.pg_vers[i] = nfsd_version[i];
 169                                 found_one = 1;
 170                         } else
 171                                 nfsd_program.pg_vers[i] = NULL;
 172                 }
 173
 174                 if (!found_one) {
 175                         for (i = NFSD_MINVERS; i < NFSD_NRVERS; i++)
 176                                 nfsd_program.pg_vers[i] = nfsd_version[i];
 177                 }
 178
 179
 180 #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
 181                 found_one = 0;
 182
 183                 for (i = NFSD_ACL_MINVERS; i < NFSD_ACL_NRVERS; i++) {
 184                         if (NFSCTL_VERISSET(nfsd_versbits, i)) {
 185                                 nfsd_acl_program.pg_vers[i] =
 186                                         nfsd_acl_version[i];
 187                                 found_one = 1;
 188                         } else
 189                                 nfsd_acl_program.pg_vers[i] = NULL;
 190                 }
 191
 192                 if (!found_one) {
 193                         for (i = NFSD_ACL_MINVERS; i < NFSD_ACL_NRVERS; i++)
 194                                 nfsd_acl_program.pg_vers[i] =
 195                                         nfsd_acl_version[i];
 196                 }
 197 #endif
 198
 199                 atomic_set(&nfsd_busy, 0);
 200                 error = -ENOMEM;
 201                 nfsd_serv = svc_create(&nfsd_program, NFSD_BUFSIZE);
 202                 if (nfsd_serv == NULL)
 203                         goto out;
 204                 error = svc_makesock(nfsd_serv, IPPROTO_UDP, port);
 205                 if (error < 0)
 206                         goto failure;
 207
 208 #ifdef CONFIG_NFSD_TCP
 209                 error = svc_makesock(nfsd_serv, IPPROTO_TCP, port);
 210                 if (error < 0)
 211                         goto failure;
 212 #endif
 213                 do_gettimeofday(&nfssvc_boot);          /* record boot time */
 214         } else
 215                 nfsd_serv->sv_nrthreads++;
 216         nrservs -= (nfsd_serv->sv_nrthreads-1);
 217         while (nrservs > 0) {
 218                 nrservs--;
 219                 __module_get(THIS_MODULE);
 220                 error = svc_create_thread(nfsd, nfsd_serv);
 221                 if (error < 0) {
 222                         module_put(THIS_MODULE);
 223                         break;
 224                 }
 225         }
 226         victim = nfsd_list.next;
 227         while (nrservs < 0 && victim != &nfsd_list) {
 228                 struct nfsd_list *nl =
 229                         list_entry(victim,struct nfsd_list, list);
 230                 victim = victim->next;
 231                 send_sig(SIG_NOCLEAN, nl->task, 1);
 232                 nrservs++;
 233         }
 234  failure:
 235         none_left = (nfsd_serv->sv_nrthreads == 1);
 236         svc_destroy(nfsd_serv);         /* Release server */
 237         if (none_left) {
 238                 nfsd_serv = NULL;
 239                 nfsd_racache_shutdown();
 240                 nfs4_state_shutdown();
 241         }
 242  out:
 243         unlock_kernel();
 244         return error;
 245 }
 246
 247 static inline void
 248 update_thread_usage(int busy_threads)
 249 {
 250         unsigned long prev_call;
 251         unsigned long diff;
 252         int decile;
 253
 254         spin_lock(&nfsd_call_lock);
 255         prev_call = nfsd_last_call;
 256         nfsd_last_call = jiffies;
 257         decile = busy_threads*10/nfsdstats.th_cnt;
 258         if (decile>0 && decile <= 10) {
 259                 diff = nfsd_last_call - prev_call;
 260                 if ( (nfsdstats.th_usage[decile-1] += diff) >= NFSD_USAGE_WRAP)
 261                         nfsdstats.th_usage[decile-1] -= NFSD_USAGE_WRAP;
 262                 if (decile == 10)
 263                         nfsdstats.th_fullcnt++;
 264         }
 265         spin_unlock(&nfsd_call_lock);
 266 }
 267
 268 /*
 269  * This is the NFS server kernel thread
 270  */
 271 static void
 272 nfsd(struct svc_rqst *rqstp)
 273 {
 274         struct svc_serv *serv = rqstp->rq_server;
 275         struct fs_struct *fsp;
 276         int             err;
 277         struct nfsd_list me;
 278         sigset_t shutdown_mask, allowed_mask;
 279
 280         /* Lock module and set up kernel thread */
 281         lock_kernel();
 282         daemonize("nfsd");
 283
 284         /* After daemonize() this kernel thread shares current->fs
 285          * with the init process. We need to create files with a
 286          * umask of 0 instead of init's umask. */
 287         fsp = copy_fs_struct(current->fs);
 288         if (!fsp) {
 289                 printk("Unable to start nfsd thread: out of memory\n");
 290                 goto out;
 291         }
 292         exit_fs(current);
 293         current->fs = fsp;
 294         current->fs->umask = 0;
 295
 296         siginitsetinv(&shutdown_mask, SHUTDOWN_SIGS);
 297         siginitsetinv(&allowed_mask, ALLOWED_SIGS);
 298
 299         nfsdstats.th_cnt++;
 300
 301         lockd_up();                             /* start lockd */
 302
 303         me.task = current;
 304         list_add(&me.list, &nfsd_list);
 305
 306         unlock_kernel();
 307
 308         /*
 309          * We want less throttling in balance_dirty_pages() so that nfs to
 310          * localhost doesn't cause nfsd to lock up due to all the client's
 311          * dirty pages.
 312          */
 313         current->flags |= PF_LESS_THROTTLE;
 314
 315         /*
 316          * The main request loop
 317          */
 318         for (;;) {
 319                 /* Block all but the shutdown signals */
 320                 sigprocmask(SIG_SETMASK, &shutdown_mask, NULL);
 321
 322                 /*
 323                  * Find a socket with data available and call its
 324                  * recvfrom routine.
 325                  */
 326                 while ((err = svc_recv(serv, rqstp,
 327                                        60*60*HZ)) == -EAGAIN)
 328                         ;
 329                 if (err < 0)
 330                         break;
 331                 update_thread_usage(atomic_read(&nfsd_busy));
 332                 atomic_inc(&nfsd_busy);
 333
 334                 /* Lock the export hash tables for reading. */
 335                 exp_readlock();
 336
 337                 /* Process request with signals blocked.  */
 338                 sigprocmask(SIG_SETMASK, &allowed_mask, NULL);
 339
 340                 svc_process(serv, rqstp);
 341
 342                 /* Unlock export hash tables */
 343                 exp_readunlock();
 344                 update_thread_usage(atomic_read(&nfsd_busy));
 345                 atomic_dec(&nfsd_busy);
 346         }
 347
 348         if (err != -EINTR) {
 349                 printk(KERN_WARNING "nfsd: terminating on error %d\n", -err);
 350         } else {
 351                 unsigned int    signo;
 352
 353                 for (signo = 1; signo <= _NSIG; signo++)
 354                         if (sigismember(&current->pending.signal, signo) &&
 355                             !sigismember(&current->blocked, signo))
 356                                 break;
 357                 err = signo;
 358         }
 359         /* Clear signals before calling lockd_down() and svc_exit_thread() */
 360         flush_signals(current);
 361
 362         lock_kernel();
 363
 364         /* Release lockd */
 365         lockd_down();
 366
 367         /* Check if this is last thread */
 368         if (serv->sv_nrthreads==1) {
 369
 370                 printk(KERN_WARNING "nfsd: last server has exited\n");
 371                 if (err != SIG_NOCLEAN) {
 372                         printk(KERN_WARNING "nfsd: unexporting all filesystems\n");
 373                         nfsd_export_flush();
 374                 }
 375                 nfsd_serv = NULL;
 376                 nfsd_racache_shutdown();        /* release read-ahead cache */
 377                 nfs4_state_shutdown();
 378         }
 379         list_del(&me.list);
 380         nfsdstats.th_cnt --;
 381
 382 out:
 383         /* Release the thread */
 384         svc_exit_thread(rqstp);
 385
 386         /* Release module */
 387         unlock_kernel();
 388         module_put_and_exit(0);
 389 }
 390
 391 int
 392 nfsd_dispatch(struct svc_rqst *rqstp, u32 *statp)
 393 {
 394         struct svc_procedure    *proc;
 395         kxdrproc_t              xdr;
 396         u32                     nfserr;
 397         u32                     *nfserrp;
 398
 399         dprintk("nfsd_dispatch: vers %d proc %d\n",
 400                                 rqstp->rq_vers, rqstp->rq_proc);
 401         proc = rqstp->rq_procinfo;
 402
 403         /* Check whether we have this call in the cache. */
 404         switch (nfsd_cache_lookup(rqstp, proc->pc_cachetype)) {
 405         case RC_INTR:
 406         case RC_DROPIT:
 407                 return 0;
 408         case RC_REPLY:
 409                 return 1;
 410         case RC_DOIT:;
 411                 /* do it */
 412         }
 413
 414         /* Decode arguments */
 415         xdr = proc->pc_decode;
 416         if (xdr && !xdr(rqstp, (u32*)rqstp->rq_arg.head[0].iov_base,
 417                         rqstp->rq_argp)) {
 418                 dprintk("nfsd: failed to decode arguments!\n");
 419                 nfsd_cache_update(rqstp, RC_NOCACHE, NULL);
 420                 *statp = rpc_garbage_args;
 421                 return 1;
 422         }
 423
 424         /* need to grab the location to store the status, as
 425          * nfsv4 does some encoding while processing
 426          */
 427         nfserrp = rqstp->rq_res.head[0].iov_base
 428                 + rqstp->rq_res.head[0].iov_len;
 429         rqstp->rq_res.head[0].iov_len += sizeof(u32);
 430
 431         /* Now call the procedure handler, and encode NFS status. */
 432         nfserr = proc->pc_func(rqstp, rqstp->rq_argp, rqstp->rq_resp);
 433         if (nfserr == nfserr_jukebox && rqstp->rq_vers == 2)
 434                 nfserr = nfserr_dropit;
 435         if (nfserr == nfserr_dropit) {
 436                 dprintk("nfsd: Dropping request due to malloc failure!\n");
 437                 nfsd_cache_update(rqstp, RC_NOCACHE, NULL);
 438                 return 0;
 439         }
 440
 441         if (rqstp->rq_proc != 0)
 442                 *nfserrp++ = nfserr;
 443
 444         /* Encode result.
 445          * For NFSv2, additional info is never returned in case of an error.
 446          */
 447         if (!(nfserr && rqstp->rq_vers == 2)) {
 448                 xdr = proc->pc_encode;
 449                 if (xdr && !xdr(rqstp, nfserrp,
 450                                 rqstp->rq_resp)) {
 451                         /* Failed to encode result. Release cache entry */
 452                         dprintk("nfsd: failed to encode result!\n");
 453                         nfsd_cache_update(rqstp, RC_NOCACHE, NULL);
 454                         *statp = rpc_system_err;
 455                         return 1;
 456                 }
 457         }
 458
 459         /* Store reply in cache. */
 460         nfsd_cache_update(rqstp, proc->pc_cachetype, statp + 1);
 461         return 1;
 462 }