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