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/nfs.h>
  39
  40 #define NLMDBG_FACILITY         NLMDBG_SVC
  41 #define LOCKD_BUFSIZE           (1024 + NLMSVC_XDRSIZE)
  42 #define ALLOWED_SIGS            (sigmask(SIGKILL))
  43
  44 static struct svc_program       nlmsvc_program;
  45
  46 struct nlmsvc_binding *         nlmsvc_ops;
  47 EXPORT_SYMBOL_GPL(nlmsvc_ops);
  48
  49 static DEFINE_MUTEX(nlmsvc_mutex);
  50 static unsigned int             nlmsvc_users;
  51 static struct task_struct       *nlmsvc_task;
  52 static struct svc_rqst          *nlmsvc_rqst;
  53 unsigned long                   nlmsvc_timeout;
  54
  55 /*
  56  * These can be set at insmod time (useful for NFS as root filesystem),
  57  * and also changed through the sysctl interface.  -- Jamie Lokier, Aug 2003
  58  */
  59 static unsigned long            nlm_grace_period;
  60 static unsigned long            nlm_timeout = LOCKD_DFLT_TIMEO;
  61 static int                      nlm_udpport, nlm_tcpport;
  62
  63 /* RLIM_NOFILE defaults to 1024. That seems like a reasonable default here. */
  64 static unsigned int             nlm_max_connections = 1024;
  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 #ifdef CONFIG_SYSCTL
  76 static struct ctl_table_header * nlm_sysctl_table;
  77 #endif
  78
  79 static unsigned long get_lockd_grace_period(void)
  80 {
  81         /* Note: nlm_timeout should always be nonzero */
  82         if (nlm_grace_period)
  83                 return roundup(nlm_grace_period, nlm_timeout) * HZ;
  84         else
  85                 return nlm_timeout * 5 * HZ;
  86 }
  87
  88 static struct lock_manager lockd_manager = {
  89 };
  90
  91 static void grace_ender(struct work_struct *not_used)
  92 {
  93         locks_end_grace(&lockd_manager);
  94 }
  95
  96 static DECLARE_DELAYED_WORK(grace_period_end, grace_ender);
  97
  98 static void set_grace_period(void)
  99 {
 100         unsigned long grace_period = get_lockd_grace_period();
 101
 102         locks_start_grace(&lockd_manager);
 103         cancel_delayed_work_sync(&grace_period_end);
 104         schedule_delayed_work(&grace_period_end, grace_period);
 105 }
 106
 107 static void restart_grace(void)
 108 {
 109         if (nlmsvc_ops) {
 110                 cancel_delayed_work_sync(&grace_period_end);
 111                 locks_end_grace(&lockd_manager);
 112                 nlmsvc_invalidate_all();
 113                 set_grace_period();
 114         }
 115 }
 116
 117 /*
 118  * This is the lockd kernel thread
 119  */
 120 static int
 121 lockd(void *vrqstp)
 122 {
 123         int             err = 0, preverr = 0;
 124         struct svc_rqst *rqstp = vrqstp;
 125
 126         /* try_to_freeze() is called from svc_recv() */
 127         set_freezable();
 128
 129         /* Allow SIGKILL to tell lockd to drop all of its locks */
 130         allow_signal(SIGKILL);
 131
 132         dprintk("NFS locking service started (ver " LOCKD_VERSION ").\n");
 133
 134         /*
 135          * FIXME: it would be nice if lockd didn't spend its entire life
 136          * running under the BKL. At the very least, it would be good to
 137          * have someone clarify what it's intended to protect here. I've
 138          * seen some handwavy posts about posix locking needing to be
 139          * done under the BKL, but it's far from clear.
 140          */
 141         lock_kernel();
 142
 143         if (!nlm_timeout)
 144                 nlm_timeout = LOCKD_DFLT_TIMEO;
 145         nlmsvc_timeout = nlm_timeout * HZ;
 146
 147         set_grace_period();
 148
 149         /*
 150          * The main request loop. We don't terminate until the last
 151          * NFS mount or NFS daemon has gone away.
 152          */
 153         while (!kthread_should_stop()) {
 154                 long timeout = MAX_SCHEDULE_TIMEOUT;
 155                 RPC_IFDEBUG(char buf[RPC_MAX_ADDRBUFLEN]);
 156
 157                 /* update sv_maxconn if it has changed */
 158                 rqstp->rq_server->sv_maxconn = nlm_max_connections;
 159
 160                 if (signalled()) {
 161                         flush_signals(current);
 162                         restart_grace();
 163                         continue;
 164                 }
 165
 166                 timeout = nlmsvc_retry_blocked();
 167
 168                 /*
 169                  * Find a socket with data available and call its
 170                  * recvfrom routine.
 171                  */
 172                 err = svc_recv(rqstp, timeout);
 173                 if (err == -EAGAIN || err == -EINTR) {
 174                         preverr = err;
 175                         continue;
 176                 }
 177                 if (err < 0) {
 178                         if (err != preverr) {
 179                                 printk(KERN_WARNING "%s: unexpected error "
 180                                         "from svc_recv (%d)\n", __func__, err);
 181                                 preverr = err;
 182                         }
 183                         schedule_timeout_interruptible(HZ);
 184                         continue;
 185                 }
 186                 preverr = err;
 187
 188                 dprintk("lockd: request from %s\n",
 189                                 svc_print_addr(rqstp, buf, sizeof(buf)));
 190
 191                 svc_process(rqstp);
 192         }
 193         flush_signals(current);
 194         cancel_delayed_work_sync(&grace_period_end);
 195         locks_end_grace(&lockd_manager);
 196         if (nlmsvc_ops)
 197                 nlmsvc_invalidate_all();
 198         nlm_shutdown_hosts();
 199         unlock_kernel();
 200         return 0;
 201 }
 202
 203 static int create_lockd_listener(struct svc_serv *serv, const char *name,
 204                                  const int family, const unsigned short port)
 205 {
 206         struct svc_xprt *xprt;
 207
 208         xprt = svc_find_xprt(serv, name, family, 0);
 209         if (xprt == NULL)
 210                 return svc_create_xprt(serv, name, family, port,
 211                                                 SVC_SOCK_DEFAULTS);
 212         svc_xprt_put(xprt);
 213         return 0;
 214 }
 215
 216 static int create_lockd_family(struct svc_serv *serv, const int family)
 217 {
 218         int err;
 219
 220         err = create_lockd_listener(serv, "udp", family, nlm_udpport);
 221         if (err < 0)
 222                 return err;
 223
 224         return create_lockd_listener(serv, "tcp", family, nlm_tcpport);
 225 }
 226
 227 /*
 228  * Ensure there are active UDP and TCP listeners for lockd.
 229  *
 230  * Even if we have only TCP NFS mounts and/or TCP NFSDs, some
 231  * local services (such as rpc.statd) still require UDP, and
 232  * some NFS servers do not yet support NLM over TCP.
 233  *
 234  * Returns zero if all listeners are available; otherwise a
 235  * negative errno value is returned.
 236  */
 237 static int make_socks(struct svc_serv *serv)
 238 {
 239         static int warned;
 240         int err;
 241
 242         err = create_lockd_family(serv, PF_INET);
 243         if (err < 0)
 244                 goto out_err;
 245
 246         err = create_lockd_family(serv, PF_INET6);
 247         if (err < 0 && err != -EAFNOSUPPORT)
 248                 goto out_err;
 249
 250         warned = 0;
 251         return 0;
 252
 253 out_err:
 254         if (warned++ == 0)
 255                 printk(KERN_WARNING
 256                         "lockd_up: makesock failed, error=%d\n", err);
 257         return err;
 258 }
 259
 260 /*
 261  * Bring up the lockd process if it's not already up.
 262  */
 263 int lockd_up(void)
 264 {
 265         struct svc_serv *serv;
 266         int             error = 0;
 267
 268         mutex_lock(&nlmsvc_mutex);
 269         /*
 270          * Check whether we're already up and running.
 271          */
 272         if (nlmsvc_rqst)
 273                 goto out;
 274
 275         /*
 276          * Sanity check: if there's no pid,
 277          * we should be the first user ...
 278          */
 279         if (nlmsvc_users)
 280                 printk(KERN_WARNING
 281                         "lockd_up: no pid, %d users??\n", nlmsvc_users);
 282
 283         error = -ENOMEM;
 284         serv = svc_create(&nlmsvc_program, LOCKD_BUFSIZE, NULL);
 285         if (!serv) {
 286                 printk(KERN_WARNING "lockd_up: create service failed\n");
 287                 goto out;
 288         }
 289
 290         error = make_socks(serv);
 291         if (error < 0)
 292                 goto destroy_and_out;
 293
 294         /*
 295          * Create the kernel thread and wait for it to start.
 296          */
 297         nlmsvc_rqst = svc_prepare_thread(serv, &serv->sv_pools[0]);
 298         if (IS_ERR(nlmsvc_rqst)) {
 299                 error = PTR_ERR(nlmsvc_rqst);
 300                 nlmsvc_rqst = NULL;
 301                 printk(KERN_WARNING
 302                         "lockd_up: svc_rqst allocation failed, error=%d\n",
 303                         error);
 304                 goto destroy_and_out;
 305         }
 306
 307         svc_sock_update_bufs(serv);
 308         serv->sv_maxconn = nlm_max_connections;
 309
 310         nlmsvc_task = kthread_run(lockd, nlmsvc_rqst, serv->sv_name);
 311         if (IS_ERR(nlmsvc_task)) {
 312                 error = PTR_ERR(nlmsvc_task);
 313                 svc_exit_thread(nlmsvc_rqst);
 314                 nlmsvc_task = NULL;
 315                 nlmsvc_rqst = NULL;
 316                 printk(KERN_WARNING
 317                         "lockd_up: kthread_run failed, error=%d\n", error);
 318                 goto destroy_and_out;
 319         }
 320
 321         /*
 322          * Note: svc_serv structures have an initial use count of 1,
 323          * so we exit through here on both success and failure.
 324          */
 325 destroy_and_out:
 326         svc_destroy(serv);
 327 out:
 328         if (!error)
 329                 nlmsvc_users++;
 330         mutex_unlock(&nlmsvc_mutex);
 331         return error;
 332 }
 333 EXPORT_SYMBOL_GPL(lockd_up);
 334
 335 /*
 336  * Decrement the user count and bring down lockd if we're the last.
 337  */
 338 void
 339 lockd_down(void)
 340 {
 341         mutex_lock(&nlmsvc_mutex);
 342         if (nlmsvc_users) {
 343                 if (--nlmsvc_users)
 344                         goto out;
 345         } else {
 346                 printk(KERN_ERR "lockd_down: no users! task=%p\n",
 347                         nlmsvc_task);
 348                 BUG();
 349         }
 350
 351         if (!nlmsvc_task) {
 352                 printk(KERN_ERR "lockd_down: no lockd running.\n");
 353                 BUG();
 354         }
 355         kthread_stop(nlmsvc_task);
 356         svc_exit_thread(nlmsvc_rqst);
 357         nlmsvc_task = NULL;
 358         nlmsvc_rqst = NULL;
 359 out:
 360         mutex_unlock(&nlmsvc_mutex);
 361 }
 362 EXPORT_SYMBOL_GPL(lockd_down);
 363
 364 #ifdef CONFIG_SYSCTL
 365
 366 /*
 367  * Sysctl parameters (same as module parameters, different interface).
 368  */
 369
 370 static ctl_table nlm_sysctls[] = {
 371         {
 372                 .procname       = "nlm_grace_period",
 373                 .data           = &nlm_grace_period,
 374                 .maxlen         = sizeof(unsigned long),
 375                 .mode           = 0644,
 376                 .proc_handler   = proc_doulongvec_minmax,
 377                 .extra1         = (unsigned long *) &nlm_grace_period_min,
 378                 .extra2         = (unsigned long *) &nlm_grace_period_max,
 379         },
 380         {
 381                 .procname       = "nlm_timeout",
 382                 .data           = &nlm_timeout,
 383                 .maxlen         = sizeof(unsigned long),
 384                 .mode           = 0644,
 385                 .proc_handler   = proc_doulongvec_minmax,
 386                 .extra1         = (unsigned long *) &nlm_timeout_min,
 387                 .extra2         = (unsigned long *) &nlm_timeout_max,
 388         },
 389         {
 390                 .procname       = "nlm_udpport",
 391                 .data           = &nlm_udpport,
 392                 .maxlen         = sizeof(int),
 393                 .mode           = 0644,
 394                 .proc_handler   = proc_dointvec_minmax,
 395                 .extra1         = (int *) &nlm_port_min,
 396                 .extra2         = (int *) &nlm_port_max,
 397         },
 398         {
 399                 .procname       = "nlm_tcpport",
 400                 .data           = &nlm_tcpport,
 401                 .maxlen         = sizeof(int),
 402                 .mode           = 0644,
 403                 .proc_handler   = proc_dointvec_minmax,
 404                 .extra1         = (int *) &nlm_port_min,
 405                 .extra2         = (int *) &nlm_port_max,
 406         },
 407         {
 408                 .procname       = "nsm_use_hostnames",
 409                 .data           = &nsm_use_hostnames,
 410                 .maxlen         = sizeof(int),
 411                 .mode           = 0644,
 412                 .proc_handler   = proc_dointvec,
 413         },
 414         {
 415                 .procname       = "nsm_local_state",
 416                 .data           = &nsm_local_state,
 417                 .maxlen         = sizeof(int),
 418                 .mode           = 0644,
 419                 .proc_handler   = proc_dointvec,
 420         },
 421         { }
 422 };
 423
 424 static ctl_table nlm_sysctl_dir[] = {
 425         {
 426                 .procname       = "nfs",
 427                 .mode           = 0555,
 428                 .child          = nlm_sysctls,
 429         },
 430         { }
 431 };
 432
 433 static ctl_table nlm_sysctl_root[] = {
 434         {
 435                 .procname       = "fs",
 436                 .mode           = 0555,
 437                 .child          = nlm_sysctl_dir,
 438         },
 439         { }
 440 };
 441
 442 #endif  /* CONFIG_SYSCTL */
 443
 444 /*
 445  * Module (and sysfs) parameters.
 446  */
 447
 448 #define param_set_min_max(name, type, which_strtol, min, max)           \
 449 static int param_set_##name(const char *val, struct kernel_param *kp)   \
 450 {                                                                       \
 451         char *endp;                                                     \
 452         __typeof__(type) num = which_strtol(val, &endp, 0);             \
 453         if (endp == val || *endp || num < (min) || num > (max))         \
 454                 return -EINVAL;                                         \
 455         *((int *) kp->arg) = num;                                       \
 456         return 0;                                                       \
 457 }
 458
 459 static inline int is_callback(u32 proc)
 460 {
 461         return proc == NLMPROC_GRANTED
 462                 || proc == NLMPROC_GRANTED_MSG
 463                 || proc == NLMPROC_TEST_RES
 464                 || proc == NLMPROC_LOCK_RES
 465                 || proc == NLMPROC_CANCEL_RES
 466                 || proc == NLMPROC_UNLOCK_RES
 467                 || proc == NLMPROC_NSM_NOTIFY;
 468 }
 469
 470
 471 static int lockd_authenticate(struct svc_rqst *rqstp)
 472 {
 473         rqstp->rq_client = NULL;
 474         switch (rqstp->rq_authop->flavour) {
 475                 case RPC_AUTH_NULL:
 476                 case RPC_AUTH_UNIX:
 477                         if (rqstp->rq_proc == 0)
 478                                 return SVC_OK;
 479                         if (is_callback(rqstp->rq_proc)) {
 480                                 /* Leave it to individual procedures to
 481                                  * call nlmsvc_lookup_host(rqstp)
 482                                  */
 483                                 return SVC_OK;
 484                         }
 485                         return svc_set_client(rqstp);
 486         }
 487         return SVC_DENIED;
 488 }
 489
 490
 491 param_set_min_max(port, int, simple_strtol, 0, 65535)
 492 param_set_min_max(grace_period, unsigned long, simple_strtoul,
 493                   nlm_grace_period_min, nlm_grace_period_max)
 494 param_set_min_max(timeout, unsigned long, simple_strtoul,
 495                   nlm_timeout_min, nlm_timeout_max)
 496
 497 MODULE_AUTHOR("Olaf Kirch <okir@monad.swb.de>");
 498 MODULE_DESCRIPTION("NFS file locking service version " LOCKD_VERSION ".");
 499 MODULE_LICENSE("GPL");
 500
 501 module_param_call(nlm_grace_period, param_set_grace_period, param_get_ulong,
 502                   &nlm_grace_period, 0644);
 503 module_param_call(nlm_timeout, param_set_timeout, param_get_ulong,
 504                   &nlm_timeout, 0644);
 505 module_param_call(nlm_udpport, param_set_port, param_get_int,
 506                   &nlm_udpport, 0644);
 507 module_param_call(nlm_tcpport, param_set_port, param_get_int,
 508                   &nlm_tcpport, 0644);
 509 module_param(nsm_use_hostnames, bool, 0644);
 510 module_param(nlm_max_connections, uint, 0644);
 511
 512 /*
 513  * Initialising and terminating the module.
 514  */
 515
 516 static int __init init_nlm(void)
 517 {
 518 #ifdef CONFIG_SYSCTL
 519         nlm_sysctl_table = register_sysctl_table(nlm_sysctl_root);
 520         return nlm_sysctl_table ? 0 : -ENOMEM;
 521 #else
 522         return 0;
 523 #endif
 524 }
 525
 526 static void __exit exit_nlm(void)
 527 {
 528         /* FIXME: delete all NLM clients */
 529         nlm_shutdown_hosts();
 530 #ifdef CONFIG_SYSCTL
 531         unregister_sysctl_table(nlm_sysctl_table);
 532 #endif
 533 }
 534
 535 module_init(init_nlm);
 536 module_exit(exit_nlm);
 537
 538 /*
 539  * Define NLM program and procedures
 540  */
 541 static struct svc_version       nlmsvc_version1 = {
 542                 .vs_vers        = 1,
 543                 .vs_nproc       = 17,
 544                 .vs_proc        = nlmsvc_procedures,
 545                 .vs_xdrsize     = NLMSVC_XDRSIZE,
 546 };
 547 static struct svc_version       nlmsvc_version3 = {
 548                 .vs_vers        = 3,
 549                 .vs_nproc       = 24,
 550                 .vs_proc        = nlmsvc_procedures,
 551                 .vs_xdrsize     = NLMSVC_XDRSIZE,
 552 };
 553 #ifdef CONFIG_LOCKD_V4
 554 static struct svc_version       nlmsvc_version4 = {
 555                 .vs_vers        = 4,
 556                 .vs_nproc       = 24,
 557                 .vs_proc        = nlmsvc_procedures4,
 558                 .vs_xdrsize     = NLMSVC_XDRSIZE,
 559 };
 560 #endif
 561 static struct svc_version *     nlmsvc_version[] = {
 562         [1] = &nlmsvc_version1,
 563         [3] = &nlmsvc_version3,
 564 #ifdef CONFIG_LOCKD_V4
 565         [4] = &nlmsvc_version4,
 566 #endif
 567 };
 568
 569 static struct svc_stat          nlmsvc_stats;
 570
 571 #define NLM_NRVERS      ARRAY_SIZE(nlmsvc_version)
 572 static struct svc_program       nlmsvc_program = {
 573         .pg_prog                = NLM_PROGRAM,          /* program number */
 574         .pg_nvers               = NLM_NRVERS,           /* number of entries in nlmsvc_version */
 575         .pg_vers                = nlmsvc_version,       /* version table */
 576         .pg_name                = "lockd",              /* service name */
 577         .pg_class               = "nfsd",               /* share authentication with nfsd */
 578         .pg_stats               = &nlmsvc_stats,        /* stats table */
 579         .pg_authenticate = &lockd_authenticate  /* export authentication */
 580 };