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