fs/lockd/svc.c

   1 /*
   2  * linux/fs/lockd/svc.c
   3  *
   4  * This is the central lockd service.
   5  *
   6  * FIXME: Separate the lockd NFS server functionality from the lockd NFS
   7  *        client functionality. Oh why didn't Sun create two separate
   8  *        services in the first place?
   9  *
  10  * Authors:     Olaf Kirch (okir@monad.swb.de)
  11  *
  12  * Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
  13  */
  14
  15 #include <linux/module.h>
  16 #include <linux/init.h>
  17 #include <linux/sysctl.h>
  18 #include <linux/moduleparam.h>
  19
  20 #include <linux/sched.h>
  21 #include <linux/errno.h>
  22 #include <linux/in.h>
  23 #include <linux/uio.h>
  24 #include <linux/slab.h>
  25 #include <linux/smp.h>
  26 #include <linux/smp_lock.h>
  27 #include <linux/mutex.h>
  28 #include <linux/kthread.h>
  29 #include <linux/freezer.h>
  30
  31 #include <linux/sunrpc/types.h>
  32 #include <linux/sunrpc/stats.h>
  33 #include <linux/sunrpc/clnt.h>
  34 #include <linux/sunrpc/svc.h>
  35 #include <linux/sunrpc/svcsock.h>
  36 #include <net/ip.h>
  37 #include <linux/lockd/lockd.h>
  38 #include <linux/lockd/sm_inter.h>
  39 #include <linux/nfs.h>
  40
  41 #define NLMDBG_FACILITY         NLMDBG_SVC
  42 #define LOCKD_BUFSIZE           (1024 + NLMSVC_XDRSIZE)
  43 #define ALLOWED_SIGS            (sigmask(SIGKILL))
  44
  45 static struct svc_program       nlmsvc_program;
  46
  47 struct nlmsvc_binding *         nlmsvc_ops;
  48 EXPORT_SYMBOL(nlmsvc_ops);
  49
  50 static DEFINE_MUTEX(nlmsvc_mutex);
  51 static unsigned int             nlmsvc_users;
  52 static struct task_struct       *nlmsvc_task;
  53 static struct svc_serv          *nlmsvc_serv;
  54 int                             nlmsvc_grace_period;
  55 unsigned long                   nlmsvc_timeout;
  56
  57 /*
  58  * These can be set at insmod time (useful for NFS as root filesystem),
  59  * and also changed through the sysctl interface.  -- Jamie Lokier, Aug 2003
  60  */
  61 static unsigned long            nlm_grace_period;
  62 static unsigned long            nlm_timeout = LOCKD_DFLT_TIMEO;
  63 static int                      nlm_udpport, nlm_tcpport;
  64 int                             nsm_use_hostnames = 0;
  65
  66 /*
  67  * Constants needed for the sysctl interface.
  68  */
  69 static const unsigned long      nlm_grace_period_min = 0;
  70 static const unsigned long      nlm_grace_period_max = 240;
  71 static const unsigned long      nlm_timeout_min = 3;
  72 static const unsigned long      nlm_timeout_max = 20;
  73 static const int                nlm_port_min = 0, nlm_port_max = 65535;
  74
  75 static struct ctl_table_header * nlm_sysctl_table;
  76
  77 static unsigned long get_lockd_grace_period(void)
  78 {
  79         /* Note: nlm_timeout should always be nonzero */
  80         if (nlm_grace_period)
  81                 return roundup(nlm_grace_period, nlm_timeout) * HZ;
  82         else
  83                 return nlm_timeout * 5 * HZ;
  84 }
  85
  86 unsigned long get_nfs_grace_period(void)
  87 {
  88         unsigned long lockdgrace = get_lockd_grace_period();
  89         unsigned long nfsdgrace = 0;
  90
  91         if (nlmsvc_ops)
  92                 nfsdgrace = nlmsvc_ops->get_grace_period();
  93
  94         return max(lockdgrace, nfsdgrace);
  95 }
  96 EXPORT_SYMBOL(get_nfs_grace_period);
  97
  98 static unsigned long set_grace_period(void)
  99 {
 100         nlmsvc_grace_period = 1;
 101         return get_nfs_grace_period() + jiffies;
 102 }
 103
 104 static inline void clear_grace_period(void)
 105 {
 106         nlmsvc_grace_period = 0;
 107 }
 108
 109 /*
 110  * This is the lockd kernel thread
 111  */
 112 static int
 113 lockd(void *vrqstp)
 114 {
 115         int             err = 0, preverr = 0;
 116         struct svc_rqst *rqstp = vrqstp;
 117         unsigned long grace_period_expire;
 118
 119         /* try_to_freeze() is called from svc_recv() */
 120         set_freezable();
 121
 122         /* Allow SIGKILL to tell lockd to drop all of its locks */
 123         allow_signal(SIGKILL);
 124
 125         dprintk("NFS locking service started (ver " LOCKD_VERSION ").\n");
 126
 127         /*
 128          * FIXME: it would be nice if lockd didn't spend its entire life
 129          * running under the BKL. At the very least, it would be good to
 130          * have someone clarify what it's intended to protect here. I've
 131          * seen some handwavy posts about posix locking needing to be
 132          * done under the BKL, but it's far from clear.
 133          */
 134         lock_kernel();
 135
 136         if (!nlm_timeout)
 137                 nlm_timeout = LOCKD_DFLT_TIMEO;
 138         nlmsvc_timeout = nlm_timeout * HZ;
 139
 140         grace_period_expire = set_grace_period();
 141
 142         /*
 143          * The main request loop. We don't terminate until the last
 144          * NFS mount or NFS daemon has gone away.
 145          */
 146         while (!kthread_should_stop()) {
 147                 long timeout = MAX_SCHEDULE_TIMEOUT;
 148                 RPC_IFDEBUG(char buf[RPC_MAX_ADDRBUFLEN]);
 149
 150                 if (signalled()) {
 151                         flush_signals(current);
 152                         if (nlmsvc_ops) {
 153                                 nlmsvc_invalidate_all();
 154                                 grace_period_expire = set_grace_period();
 155                         }
 156                         continue;
 157                 }
 158
 159                 /*
 160                  * Retry any blocked locks that have been notified by
 161                  * the VFS. Don't do this during grace period.
 162                  * (Theoretically, there shouldn't even be blocked locks
 163                  * during grace period).
 164                  */
 165                 if (!nlmsvc_grace_period) {
 166                         timeout = nlmsvc_retry_blocked();
 167                 } else if (time_before(grace_period_expire, jiffies))
 168                         clear_grace_period();
 169
 170                 /*
 171                  * Find a socket with data available and call its
 172                  * recvfrom routine.
 173                  */
 174                 err = svc_recv(rqstp, timeout);
 175                 if (err == -EAGAIN || err == -EINTR) {
 176                         preverr = err;
 177                         continue;
 178                 }
 179                 if (err < 0) {
 180                         if (err != preverr) {
 181                                 printk(KERN_WARNING "%s: unexpected error "
 182                                         "from svc_recv (%d)\n", __func__, err);
 183                                 preverr = err;
 184                         }
 185                         schedule_timeout_interruptible(HZ);
 186                         continue;
 187                 }
 188                 preverr = err;
 189
 190                 dprintk("lockd: request from %s\n",
 191                                 svc_print_addr(rqstp, buf, sizeof(buf)));
 192
 193                 svc_process(rqstp);
 194         }
 195
 196         flush_signals(current);
 197         if (nlmsvc_ops)
 198                 nlmsvc_invalidate_all();
 199         nlm_shutdown_hosts();
 200
 201         unlock_kernel();
 202
 203         nlmsvc_task = NULL;
 204         nlmsvc_serv = NULL;
 205
 206         /* Exit the RPC thread */
 207         svc_exit_thread(rqstp);
 208
 209         return 0;
 210 }
 211
 212 /*
 213  * Make any sockets that are needed but not present.
 214  * If nlm_udpport or nlm_tcpport were set as module
 215  * options, make those sockets unconditionally
 216  */
 217 static int make_socks(struct svc_serv *serv, int proto)
 218 {
 219         static int warned;
 220         struct svc_xprt *xprt;
 221         int err = 0;
 222
 223         if (proto == IPPROTO_UDP || nlm_udpport) {
 224                 xprt = svc_find_xprt(serv, "udp", 0, 0);
 225                 if (!xprt)
 226                         err = svc_create_xprt(serv, "udp", nlm_udpport,
 227                                               SVC_SOCK_DEFAULTS);
 228                 else
 229                         svc_xprt_put(xprt);
 230         }
 231         if (err >= 0 && (proto == IPPROTO_TCP || nlm_tcpport)) {
 232                 xprt = svc_find_xprt(serv, "tcp", 0, 0);
 233                 if (!xprt)
 234                         err = svc_create_xprt(serv, "tcp", nlm_tcpport,
 235                                               SVC_SOCK_DEFAULTS);
 236                 else
 237                         svc_xprt_put(xprt);
 238         }
 239         if (err >= 0) {
 240                 warned = 0;
 241                 err = 0;
 242         } else if (warned++ == 0)
 243                 printk(KERN_WARNING
 244                        "lockd_up: makesock failed, error=%d\n", err);
 245         return err;
 246 }
 247
 248 /*
 249  * Bring up the lockd process if it's not already up.
 250  */
 251 int
 252 lockd_up(int proto) /* Maybe add a 'family' option when IPv6 is supported ?? */
 253 {
 254         struct svc_serv *serv;
 255         struct svc_rqst *rqstp;
 256         int             error = 0;
 257
 258         mutex_lock(&nlmsvc_mutex);
 259         /*
 260          * Check whether we're already up and running.
 261          */
 262         if (nlmsvc_serv) {
 263                 if (proto)
 264                         error = make_socks(nlmsvc_serv, proto);
 265                 goto out;
 266         }
 267
 268         /*
 269          * Sanity check: if there's no pid,
 270          * we should be the first user ...
 271          */
 272         if (nlmsvc_users)
 273                 printk(KERN_WARNING
 274                         "lockd_up: no pid, %d users??\n", nlmsvc_users);
 275
 276         error = -ENOMEM;
 277         serv = svc_create(&nlmsvc_program, LOCKD_BUFSIZE, NULL);
 278         if (!serv) {
 279                 printk(KERN_WARNING "lockd_up: create service failed\n");
 280                 goto out;
 281         }
 282
 283         if ((error = make_socks(serv, proto)) < 0)
 284                 goto destroy_and_out;
 285
 286         /*
 287          * Create the kernel thread and wait for it to start.
 288          */
 289         rqstp = svc_prepare_thread(serv, &serv->sv_pools[0]);
 290         if (IS_ERR(rqstp)) {
 291                 error = PTR_ERR(rqstp);
 292                 printk(KERN_WARNING
 293                         "lockd_up: svc_rqst allocation failed, error=%d\n",
 294                         error);
 295                 goto destroy_and_out;
 296         }
 297
 298         svc_sock_update_bufs(serv);
 299         nlmsvc_serv = rqstp->rq_server;
 300
 301         nlmsvc_task = kthread_run(lockd, rqstp, serv->sv_name);
 302         if (IS_ERR(nlmsvc_task)) {
 303                 error = PTR_ERR(nlmsvc_task);
 304                 nlmsvc_task = NULL;
 305                 nlmsvc_serv = NULL;
 306                 printk(KERN_WARNING
 307                         "lockd_up: kthread_run failed, error=%d\n", error);
 308                 svc_exit_thread(rqstp);
 309                 goto destroy_and_out;
 310         }
 311
 312         /*
 313          * Note: svc_serv structures have an initial use count of 1,
 314          * so we exit through here on both success and failure.
 315          */
 316 destroy_and_out:
 317         svc_destroy(serv);
 318 out:
 319         if (!error)
 320                 nlmsvc_users++;
 321         mutex_unlock(&nlmsvc_mutex);
 322         return error;
 323 }
 324 EXPORT_SYMBOL(lockd_up);
 325
 326 /*
 327  * Decrement the user count and bring down lockd if we're the last.
 328  */
 329 void
 330 lockd_down(void)
 331 {
 332         mutex_lock(&nlmsvc_mutex);
 333         if (nlmsvc_users) {
 334                 if (--nlmsvc_users)
 335                         goto out;
 336         } else {
 337                 printk(KERN_ERR "lockd_down: no users! task=%p\n",
 338                         nlmsvc_task);
 339                 BUG();
 340         }
 341
 342         if (!nlmsvc_task) {
 343                 printk(KERN_ERR "lockd_down: no lockd running.\n");
 344                 BUG();
 345         }
 346         kthread_stop(nlmsvc_task);
 347 out:
 348         mutex_unlock(&nlmsvc_mutex);
 349 }
 350 EXPORT_SYMBOL(lockd_down);
 351
 352 /*
 353  * Sysctl parameters (same as module parameters, different interface).
 354  */
 355
 356 static ctl_table nlm_sysctls[] = {
 357         {
 358                 .ctl_name       = CTL_UNNUMBERED,
 359                 .procname       = "nlm_grace_period",
 360                 .data           = &nlm_grace_period,
 361                 .maxlen         = sizeof(unsigned long),
 362                 .mode           = 0644,
 363                 .proc_handler   = &proc_doulongvec_minmax,
 364                 .extra1         = (unsigned long *) &nlm_grace_period_min,
 365                 .extra2         = (unsigned long *) &nlm_grace_period_max,
 366         },
 367         {
 368                 .ctl_name       = CTL_UNNUMBERED,
 369                 .procname       = "nlm_timeout",
 370                 .data           = &nlm_timeout,
 371                 .maxlen         = sizeof(unsigned long),
 372                 .mode           = 0644,
 373                 .proc_handler   = &proc_doulongvec_minmax,
 374                 .extra1         = (unsigned long *) &nlm_timeout_min,
 375                 .extra2         = (unsigned long *) &nlm_timeout_max,
 376         },
 377         {
 378                 .ctl_name       = CTL_UNNUMBERED,
 379                 .procname       = "nlm_udpport",
 380                 .data           = &nlm_udpport,
 381                 .maxlen         = sizeof(int),
 382                 .mode           = 0644,
 383                 .proc_handler   = &proc_dointvec_minmax,
 384                 .extra1         = (int *) &nlm_port_min,
 385                 .extra2         = (int *) &nlm_port_max,
 386         },
 387         {
 388                 .ctl_name       = CTL_UNNUMBERED,
 389                 .procname       = "nlm_tcpport",
 390                 .data           = &nlm_tcpport,
 391                 .maxlen         = sizeof(int),
 392                 .mode           = 0644,
 393                 .proc_handler   = &proc_dointvec_minmax,
 394                 .extra1         = (int *) &nlm_port_min,
 395                 .extra2         = (int *) &nlm_port_max,
 396         },
 397         {
 398                 .ctl_name       = CTL_UNNUMBERED,
 399                 .procname       = "nsm_use_hostnames",
 400                 .data           = &nsm_use_hostnames,
 401                 .maxlen         = sizeof(int),
 402                 .mode           = 0644,
 403                 .proc_handler   = &proc_dointvec,
 404         },
 405         {
 406                 .ctl_name       = CTL_UNNUMBERED,
 407                 .procname       = "nsm_local_state",
 408                 .data           = &nsm_local_state,
 409                 .maxlen         = sizeof(int),
 410                 .mode           = 0644,
 411                 .proc_handler   = &proc_dointvec,
 412         },
 413         { .ctl_name = 0 }
 414 };
 415
 416 static ctl_table nlm_sysctl_dir[] = {
 417         {
 418                 .ctl_name       = CTL_UNNUMBERED,
 419                 .procname       = "nfs",
 420                 .mode           = 0555,
 421                 .child          = nlm_sysctls,
 422         },
 423         { .ctl_name = 0 }
 424 };
 425
 426 static ctl_table nlm_sysctl_root[] = {
 427         {
 428                 .ctl_name       = CTL_FS,
 429                 .procname       = "fs",
 430                 .mode           = 0555,
 431                 .child          = nlm_sysctl_dir,
 432         },
 433         { .ctl_name = 0 }
 434 };
 435
 436 /*
 437  * Module (and sysfs) parameters.
 438  */
 439
 440 #define param_set_min_max(name, type, which_strtol, min, max)           \
 441 static int param_set_##name(const char *val, struct kernel_param *kp)   \
 442 {                                                                       \
 443         char *endp;                                                     \
 444         __typeof__(type) num = which_strtol(val, &endp, 0);             \
 445         if (endp == val || *endp || num < (min) || num > (max))         \
 446                 return -EINVAL;                                         \
 447         *((int *) kp->arg) = num;                                       \
 448         return 0;                                                       \
 449 }
 450
 451 static inline int is_callback(u32 proc)
 452 {
 453         return proc == NLMPROC_GRANTED
 454                 || proc == NLMPROC_GRANTED_MSG
 455                 || proc == NLMPROC_TEST_RES
 456                 || proc == NLMPROC_LOCK_RES
 457                 || proc == NLMPROC_CANCEL_RES
 458                 || proc == NLMPROC_UNLOCK_RES
 459                 || proc == NLMPROC_NSM_NOTIFY;
 460 }
 461
 462
 463 static int lockd_authenticate(struct svc_rqst *rqstp)
 464 {
 465         rqstp->rq_client = NULL;
 466         switch (rqstp->rq_authop->flavour) {
 467                 case RPC_AUTH_NULL:
 468                 case RPC_AUTH_UNIX:
 469                         if (rqstp->rq_proc == 0)
 470                                 return SVC_OK;
 471                         if (is_callback(rqstp->rq_proc)) {
 472                                 /* Leave it to individual procedures to
 473                                  * call nlmsvc_lookup_host(rqstp)
 474                                  */
 475                                 return SVC_OK;
 476                         }
 477                         return svc_set_client(rqstp);
 478         }
 479         return SVC_DENIED;
 480 }
 481
 482
 483 param_set_min_max(port, int, simple_strtol, 0, 65535)
 484 param_set_min_max(grace_period, unsigned long, simple_strtoul,
 485                   nlm_grace_period_min, nlm_grace_period_max)
 486 param_set_min_max(timeout, unsigned long, simple_strtoul,
 487                   nlm_timeout_min, nlm_timeout_max)
 488
 489 MODULE_AUTHOR("Olaf Kirch <okir@monad.swb.de>");
 490 MODULE_DESCRIPTION("NFS file locking service version " LOCKD_VERSION ".");
 491 MODULE_LICENSE("GPL");
 492
 493 module_param_call(nlm_grace_period, param_set_grace_period, param_get_ulong,
 494                   &nlm_grace_period, 0644);
 495 module_param_call(nlm_timeout, param_set_timeout, param_get_ulong,
 496                   &nlm_timeout, 0644);
 497 module_param_call(nlm_udpport, param_set_port, param_get_int,
 498                   &nlm_udpport, 0644);
 499 module_param_call(nlm_tcpport, param_set_port, param_get_int,
 500                   &nlm_tcpport, 0644);
 501 module_param(nsm_use_hostnames, bool, 0644);
 502
 503 /*
 504  * Initialising and terminating the module.
 505  */
 506
 507 static int __init init_nlm(void)
 508 {
 509         nlm_sysctl_table = register_sysctl_table(nlm_sysctl_root);
 510         return nlm_sysctl_table ? 0 : -ENOMEM;
 511 }
 512
 513 static void __exit exit_nlm(void)
 514 {
 515         /* FIXME: delete all NLM clients */
 516         nlm_shutdown_hosts();
 517         unregister_sysctl_table(nlm_sysctl_table);
 518 }
 519
 520 module_init(init_nlm);
 521 module_exit(exit_nlm);
 522
 523 /*
 524  * Define NLM program and procedures
 525  */
 526 static struct svc_version       nlmsvc_version1 = {
 527                 .vs_vers        = 1,
 528                 .vs_nproc       = 17,
 529                 .vs_proc        = nlmsvc_procedures,
 530                 .vs_xdrsize     = NLMSVC_XDRSIZE,
 531 };
 532 static struct svc_version       nlmsvc_version3 = {
 533                 .vs_vers        = 3,
 534                 .vs_nproc       = 24,
 535                 .vs_proc        = nlmsvc_procedures,
 536                 .vs_xdrsize     = NLMSVC_XDRSIZE,
 537 };
 538 #ifdef CONFIG_LOCKD_V4
 539 static struct svc_version       nlmsvc_version4 = {
 540                 .vs_vers        = 4,
 541                 .vs_nproc       = 24,
 542                 .vs_proc        = nlmsvc_procedures4,
 543                 .vs_xdrsize     = NLMSVC_XDRSIZE,
 544 };
 545 #endif
 546 static struct svc_version *     nlmsvc_version[] = {
 547         [1] = &nlmsvc_version1,
 548         [3] = &nlmsvc_version3,
 549 #ifdef CONFIG_LOCKD_V4
 550         [4] = &nlmsvc_version4,
 551 #endif
 552 };
 553
 554 static struct svc_stat          nlmsvc_stats;
 555
 556 #define NLM_NRVERS      ARRAY_SIZE(nlmsvc_version)
 557 static struct svc_program       nlmsvc_program = {
 558         .pg_prog                = NLM_PROGRAM,          /* program number */
 559         .pg_nvers               = NLM_NRVERS,           /* number of entries in nlmsvc_version */
 560         .pg_vers                = nlmsvc_version,       /* version table */
 561         .pg_name                = "lockd",              /* service name */
 562         .pg_class               = "nfsd",               /* share authentication with nfsd */
 563         .pg_stats               = &nlmsvc_stats,        /* stats table */
 564         .pg_authenticate = &lockd_authenticate  /* export authentication */
 565 };