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/smp.h>
  25 #include <linux/smp_lock.h>
  26 #include <linux/mutex.h>
  27 #include <linux/kthread.h>
  28 #include <linux/freezer.h>
  29
  30 #include <linux/sunrpc/types.h>
  31 #include <linux/sunrpc/stats.h>
  32 #include <linux/sunrpc/clnt.h>
  33 #include <linux/sunrpc/svc.h>
  34 #include <linux/sunrpc/svcsock.h>
  35 #include <net/ip.h>
  36 #include <linux/lockd/lockd.h>
  37 #include <linux/nfs.h>
  38
  39 #define NLMDBG_FACILITY         NLMDBG_SVC
  40 #define LOCKD_BUFSIZE           (1024 + NLMSVC_XDRSIZE)
  41 #define ALLOWED_SIGS            (sigmask(SIGKILL))
  42
  43 static struct svc_program       nlmsvc_program;
  44
  45 struct nlmsvc_binding *         nlmsvc_ops;
  46 EXPORT_SYMBOL_GPL(nlmsvc_ops);
  47
  48 static DEFINE_MUTEX(nlmsvc_mutex);
  49 static unsigned int             nlmsvc_users;
  50 static struct task_struct       *nlmsvc_task;
  51 static struct svc_rqst          *nlmsvc_rqst;
  52 unsigned long                   nlmsvc_timeout;
  53
  54 /*
  55  * These can be set at insmod time (useful for NFS as root filesystem),
  56  * and also changed through the sysctl interface.  -- Jamie Lokier, Aug 2003
  57  */
  58 static unsigned long            nlm_grace_period;
  59 static unsigned long            nlm_timeout = LOCKD_DFLT_TIMEO;
  60 static int                      nlm_udpport, nlm_tcpport;
  61
  62 /* RLIM_NOFILE defaults to 1024. That seems like a reasonable default here. */
  63 static unsigned int             nlm_max_connections = 1024;
  64
  65 /*
  66  * Constants needed for the sysctl interface.
  67  */
  68 static const unsigned long      nlm_grace_period_min = 0;
  69 static const unsigned long      nlm_grace_period_max = 240;
  70 static const unsigned long      nlm_timeout_min = 3;
  71 static const unsigned long      nlm_timeout_max = 20;
  72 static const int                nlm_port_min = 0, nlm_port_max = 65535;
  73
  74 #ifdef CONFIG_SYSCTL
  75 static struct ctl_table_header * nlm_sysctl_table;
  76 #endif
  77
  78 static unsigned long get_lockd_grace_period(void)
  79 {
  80         /* Note: nlm_timeout should always be nonzero */
  81         if (nlm_grace_period)
  82                 return roundup(nlm_grace_period, nlm_timeout) * HZ;
  83         else
  84                 return nlm_timeout * 5 * HZ;
  85 }
  86
  87 static struct lock_manager lockd_manager = {
  88 };
  89
  90 static void grace_ender(struct work_struct *not_used)
  91 {
  92         locks_end_grace(&lockd_manager);
  93 }
  94
  95 static DECLARE_DELAYED_WORK(grace_period_end, grace_ender);
  96
  97 static void set_grace_period(void)
  98 {
  99         unsigned long grace_period = get_lockd_grace_period();
 100
 101         locks_start_grace(&lockd_manager);
 102         cancel_delayed_work_sync(&grace_period_end);
 103         schedule_delayed_work(&grace_period_end, grace_period);
 104 }
 105
 106 static void restart_grace(void)
 107 {
 108         if (nlmsvc_ops) {
 109                 cancel_delayed_work_sync(&grace_period_end);
 110                 locks_end_grace(&lockd_manager);
 111                 nlmsvc_invalidate_all();
 112                 set_grace_period();
 113         }
 114 }
 115
 116 /*
 117  * This is the lockd kernel thread
 118  */
 119 static int
 120 lockd(void *vrqstp)
 121 {
 122         int             err = 0, preverr = 0;
 123         struct svc_rqst *rqstp = vrqstp;
 124
 125         /* try_to_freeze() is called from svc_recv() */
 126         set_freezable();
 127
 128         /* Allow SIGKILL to tell lockd to drop all of its locks */
 129         allow_signal(SIGKILL);
 130
 131         dprintk("NFS locking service started (ver " LOCKD_VERSION ").\n");
 132
 133         /*
 134          * FIXME: it would be nice if lockd didn't spend its entire life
 135          * running under the BKL. At the very least, it would be good to
 136          * have someone clarify what it's intended to protect here. I've
 137          * seen some handwavy posts about posix locking needing to be
 138          * done under the BKL, but it's far from clear.
 139          */
 140         lock_kernel();
 141
 142         if (!nlm_timeout)
 143                 nlm_timeout = LOCKD_DFLT_TIMEO;
 144         nlmsvc_timeout = nlm_timeout * HZ;
 145
 146         set_grace_period();
 147
 148         /*
 149          * The main request loop. We don't terminate until the last
 150          * NFS mount or NFS daemon has gone away.
 151          */
 152         while (!kthread_should_stop()) {
 153                 long timeout = MAX_SCHEDULE_TIMEOUT;
 154                 RPC_IFDEBUG(char buf[RPC_MAX_ADDRBUFLEN]);
 155
 156                 /* update sv_maxconn if it has changed */
 157                 rqstp->rq_server->sv_maxconn = nlm_max_connections;
 158
 159                 if (signalled()) {
 160                         flush_signals(current);
 161                         restart_grace();
 162                         continue;
 163                 }
 164
 165                 timeout = nlmsvc_retry_blocked();
 166
 167                 /*
 168                  * Find a socket with data available and call its
 169                  * recvfrom routine.
 170                  */
 171                 err = svc_recv(rqstp, timeout);
 172                 if (err == -EAGAIN || err == -EINTR) {
 173                         preverr = err;
 174                         continue;
 175                 }
 176                 if (err < 0) {
 177                         if (err != preverr) {
 178                                 printk(KERN_WARNING "%s: unexpected error "
 179                                         "from svc_recv (%d)\n", __func__, err);
 180                                 preverr = err;
 181                         }
 182                         schedule_timeout_interruptible(HZ);
 183                         continue;
 184                 }
 185                 preverr = err;
 186
 187                 dprintk("lockd: request from %s\n",
 188                                 svc_print_addr(rqstp, buf, sizeof(buf)));
 189
 190                 svc_process(rqstp);
 191         }
 192         flush_signals(current);
 193         cancel_delayed_work_sync(&grace_period_end);
 194         locks_end_grace(&lockd_manager);
 195         if (nlmsvc_ops)
 196                 nlmsvc_invalidate_all();
 197         nlm_shutdown_hosts();
 198         unlock_kernel();
 199         return 0;
 200 }
 201
 202 static int create_lockd_listener(struct svc_serv *serv, const char *name,
 203                                  const int family, const unsigned short port)
 204 {
 205         struct svc_xprt *xprt;
 206
 207         xprt = svc_find_xprt(serv, name, family, 0);
 208         if (xprt == NULL)
 209                 return svc_create_xprt(serv, name, family, port,
 210                                                 SVC_SOCK_DEFAULTS);
 211         svc_xprt_put(xprt);
 212         return 0;
 213 }
 214
 215 static int create_lockd_family(struct svc_serv *serv, const int family)
 216 {
 217         int err;
 218
 219         err = create_lockd_listener(serv, "udp", family, nlm_udpport);
 220         if (err < 0)
 221                 return err;
 222
 223         return create_lockd_listener(serv, "tcp", family, nlm_tcpport);
 224 }
 225
 226 /*
 227  * Ensure there are active UDP and TCP listeners for lockd.
 228  *
 229  * Even if we have only TCP NFS mounts and/or TCP NFSDs, some
 230  * local services (such as rpc.statd) still require UDP, and
 231  * some NFS servers do not yet support NLM over TCP.
 232  *
 233  * Returns zero if all listeners are available; otherwise a
 234  * negative errno value is returned.
 235  */
 236 static int make_socks(struct svc_serv *serv)
 237 {
 238         static int warned;
 239         int err;
 240
 241         err = create_lockd_family(serv, PF_INET);
 242         if (err < 0)
 243                 goto out_err;
 244
 245         err = create_lockd_family(serv, PF_INET6);
 246         if (err < 0 && err != -EAFNOSUPPORT)
 247                 goto out_err;
 248
 249         warned = 0;
 250         return 0;
 251
 252 out_err:
 253         if (warned++ == 0)
 254                 printk(KERN_WARNING
 255                         "lockd_up: makesock failed, error=%d\n", err);
 256         return err;
 257 }
 258
 259 /*
 260  * Bring up the lockd process if it's not already up.
 261  */
 262 int lockd_up(void)
 263 {
 264         struct svc_serv *serv;
 265         int             error = 0;
 266
 267         mutex_lock(&nlmsvc_mutex);
 268         /*
 269          * Check whether we're already up and running.
 270          */
 271         if (nlmsvc_rqst)
 272                 goto out;
 273
 274         /*
 275          * Sanity check: if there's no pid,
 276          * we should be the first user ...
 277          */
 278         if (nlmsvc_users)
 279                 printk(KERN_WARNING
 280                         "lockd_up: no pid, %d users??\n", nlmsvc_users);
 281
 282         error = -ENOMEM;
 283         serv = svc_create(&nlmsvc_program, LOCKD_BUFSIZE, NULL);
 284         if (!serv) {
 285                 printk(KERN_WARNING "lockd_up: create service failed\n");
 286                 goto out;
 287         }
 288
 289         error = make_socks(serv);
 290         if (error < 0)
 291                 goto destroy_and_out;
 292
 293         /*
 294          * Create the kernel thread and wait for it to start.
 295          */
 296         nlmsvc_rqst = svc_prepare_thread(serv, &serv->sv_pools[0]);
 297         if (IS_ERR(nlmsvc_rqst)) {
 298                 error = PTR_ERR(nlmsvc_rqst);
 299                 nlmsvc_rqst = NULL;
 300                 printk(KERN_WARNING
 301                         "lockd_up: svc_rqst allocation failed, error=%d\n",
 302                         error);
 303                 goto destroy_and_out;
 304         }
 305
 306         svc_sock_update_bufs(serv);
 307         serv->sv_maxconn = nlm_max_connections;
 308
 309         nlmsvc_task = kthread_run(lockd, nlmsvc_rqst, serv->sv_name);
 310         if (IS_ERR(nlmsvc_task)) {
 311                 error = PTR_ERR(nlmsvc_task);
 312                 svc_exit_thread(nlmsvc_rqst);
 313                 nlmsvc_task = NULL;
 314                 nlmsvc_rqst = NULL;
 315                 printk(KERN_WARNING
 316                         "lockd_up: kthread_run failed, error=%d\n", error);
 317                 goto destroy_and_out;
 318         }
 319
 320         /*
 321          * Note: svc_serv structures have an initial use count of 1,
 322          * so we exit through here on both success and failure.
 323          */
 324 destroy_and_out:
 325         svc_destroy(serv);
 326 out:
 327         if (!error)
 328                 nlmsvc_users++;
 329         mutex_unlock(&nlmsvc_mutex);
 330         return error;
 331 }
 332 EXPORT_SYMBOL_GPL(lockd_up);
 333
 334 /*
 335  * Decrement the user count and bring down lockd if we're the last.
 336  */
 337 void
 338 lockd_down(void)
 339 {
 340         mutex_lock(&nlmsvc_mutex);
 341         if (nlmsvc_users) {
 342                 if (--nlmsvc_users)
 343                         goto out;
 344         } else {
 345                 printk(KERN_ERR "lockd_down: no users! task=%p\n",
 346                         nlmsvc_task);
 347                 BUG();
 348         }
 349
 350         if (!nlmsvc_task) {
 351                 printk(KERN_ERR "lockd_down: no lockd running.\n");
 352                 BUG();
 353         }
 354         kthread_stop(nlmsvc_task);
 355         svc_exit_thread(nlmsvc_rqst);
 356         nlmsvc_task = NULL;
 357         nlmsvc_rqst = NULL;
 358 out:
 359         mutex_unlock(&nlmsvc_mutex);
 360 }
 361 EXPORT_SYMBOL_GPL(lockd_down);
 362
 363 #ifdef CONFIG_SYSCTL
 364
 365 /*
 366  * Sysctl parameters (same as module parameters, different interface).
 367  */
 368
 369 static ctl_table nlm_sysctls[] = {
 370         {
 371                 .procname       = "nlm_grace_period",
 372                 .data           = &nlm_grace_period,
 373                 .maxlen         = sizeof(unsigned long),
 374                 .mode           = 0644,
 375                 .proc_handler   = proc_doulongvec_minmax,
 376                 .extra1         = (unsigned long *) &nlm_grace_period_min,
 377                 .extra2         = (unsigned long *) &nlm_grace_period_max,
 378         },
 379         {
 380                 .procname       = "nlm_timeout",
 381                 .data           = &nlm_timeout,
 382                 .maxlen         = sizeof(unsigned long),
 383                 .mode           = 0644,
 384                 .proc_handler   = proc_doulongvec_minmax,
 385                 .extra1         = (unsigned long *) &nlm_timeout_min,
 386                 .extra2         = (unsigned long *) &nlm_timeout_max,
 387         },
 388         {
 389                 .procname       = "nlm_udpport",
 390                 .data           = &nlm_udpport,
 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                 .procname       = "nlm_tcpport",
 399                 .data           = &nlm_tcpport,
 400                 .maxlen         = sizeof(int),
 401                 .mode           = 0644,
 402                 .proc_handler   = proc_dointvec_minmax,
 403                 .extra1         = (int *) &nlm_port_min,
 404                 .extra2         = (int *) &nlm_port_max,
 405         },
 406         {
 407                 .procname       = "nsm_use_hostnames",
 408                 .data           = &nsm_use_hostnames,
 409                 .maxlen         = sizeof(int),
 410                 .mode           = 0644,
 411                 .proc_handler   = proc_dointvec,
 412         },
 413         {
 414                 .procname       = "nsm_local_state",
 415                 .data           = &nsm_local_state,
 416                 .maxlen         = sizeof(int),
 417                 .mode           = 0644,
 418                 .proc_handler   = proc_dointvec,
 419         },
 420         { }
 421 };
 422
 423 static ctl_table nlm_sysctl_dir[] = {
 424         {
 425                 .procname       = "nfs",
 426                 .mode           = 0555,
 427                 .child          = nlm_sysctls,
 428         },
 429         { }
 430 };
 431
 432 static ctl_table nlm_sysctl_root[] = {
 433         {
 434                 .procname       = "fs",
 435                 .mode           = 0555,
 436                 .child          = nlm_sysctl_dir,
 437         },
 438         { }
 439 };
 440
 441 #endif  /* CONFIG_SYSCTL */
 442
 443 /*
 444  * Module (and sysfs) parameters.
 445  */
 446
 447 #define param_set_min_max(name, type, which_strtol, min, max)           \
 448 static int param_set_##name(const char *val, struct kernel_param *kp)   \
 449 {                                                                       \
 450         char *endp;                                                     \
 451         __typeof__(type) num = which_strtol(val, &endp, 0);             \
 452         if (endp == val || *endp || num < (min) || num > (max))         \
 453                 return -EINVAL;                                         \
 454         *((int *) kp->arg) = num;                                       \
 455         return 0;                                                       \
 456 }
 457
 458 static inline int is_callback(u32 proc)
 459 {
 460         return proc == NLMPROC_GRANTED
 461                 || proc == NLMPROC_GRANTED_MSG
 462                 || proc == NLMPROC_TEST_RES
 463                 || proc == NLMPROC_LOCK_RES
 464                 || proc == NLMPROC_CANCEL_RES
 465                 || proc == NLMPROC_UNLOCK_RES
 466                 || proc == NLMPROC_NSM_NOTIFY;
 467 }
 468
 469
 470 static int lockd_authenticate(struct svc_rqst *rqstp)
 471 {
 472         rqstp->rq_client = NULL;
 473         switch (rqstp->rq_authop->flavour) {
 474                 case RPC_AUTH_NULL:
 475                 case RPC_AUTH_UNIX:
 476                         if (rqstp->rq_proc == 0)
 477                                 return SVC_OK;
 478                         if (is_callback(rqstp->rq_proc)) {
 479                                 /* Leave it to individual procedures to
 480                                  * call nlmsvc_lookup_host(rqstp)
 481                                  */
 482                                 return SVC_OK;
 483                         }
 484                         return svc_set_client(rqstp);
 485         }
 486         return SVC_DENIED;
 487 }
 488
 489
 490 param_set_min_max(port, int, simple_strtol, 0, 65535)
 491 param_set_min_max(grace_period, unsigned long, simple_strtoul,
 492                   nlm_grace_period_min, nlm_grace_period_max)
 493 param_set_min_max(timeout, unsigned long, simple_strtoul,
 494                   nlm_timeout_min, nlm_timeout_max)
 495
 496 MODULE_AUTHOR("Olaf Kirch <okir@monad.swb.de>");
 497 MODULE_DESCRIPTION("NFS file locking service version " LOCKD_VERSION ".");
 498 MODULE_LICENSE("GPL");
 499
 500 module_param_call(nlm_grace_period, param_set_grace_period, param_get_ulong,
 501                   &nlm_grace_period, 0644);
 502 module_param_call(nlm_timeout, param_set_timeout, param_get_ulong,
 503                   &nlm_timeout, 0644);
 504 module_param_call(nlm_udpport, param_set_port, param_get_int,
 505                   &nlm_udpport, 0644);
 506 module_param_call(nlm_tcpport, param_set_port, param_get_int,
 507                   &nlm_tcpport, 0644);
 508 module_param(nsm_use_hostnames, bool, 0644);
 509 module_param(nlm_max_connections, uint, 0644);
 510
 511 /*
 512  * Initialising and terminating the module.
 513  */
 514
 515 static int __init init_nlm(void)
 516 {
 517 #ifdef CONFIG_SYSCTL
 518         nlm_sysctl_table = register_sysctl_table(nlm_sysctl_root);
 519         return nlm_sysctl_table ? 0 : -ENOMEM;
 520 #else
 521         return 0;
 522 #endif
 523 }
 524
 525 static void __exit exit_nlm(void)
 526 {
 527         /* FIXME: delete all NLM clients */
 528         nlm_shutdown_hosts();
 529 #ifdef CONFIG_SYSCTL
 530         unregister_sysctl_table(nlm_sysctl_table);
 531 #endif
 532 }
 533
 534 module_init(init_nlm);
 535 module_exit(exit_nlm);
 536
 537 /*
 538  * Define NLM program and procedures
 539  */
 540 static struct svc_version       nlmsvc_version1 = {
 541                 .vs_vers        = 1,
 542                 .vs_nproc       = 17,
 543                 .vs_proc        = nlmsvc_procedures,
 544                 .vs_xdrsize     = NLMSVC_XDRSIZE,
 545 };
 546 static struct svc_version       nlmsvc_version3 = {
 547                 .vs_vers        = 3,
 548                 .vs_nproc       = 24,
 549                 .vs_proc        = nlmsvc_procedures,
 550                 .vs_xdrsize     = NLMSVC_XDRSIZE,
 551 };
 552 #ifdef CONFIG_LOCKD_V4
 553 static struct svc_version       nlmsvc_version4 = {
 554                 .vs_vers        = 4,
 555                 .vs_nproc       = 24,
 556                 .vs_proc        = nlmsvc_procedures4,
 557                 .vs_xdrsize     = NLMSVC_XDRSIZE,
 558 };
 559 #endif
 560 static struct svc_version *     nlmsvc_version[] = {
 561         [1] = &nlmsvc_version1,
 562         [3] = &nlmsvc_version3,
 563 #ifdef CONFIG_LOCKD_V4
 564         [4] = &nlmsvc_version4,
 565 #endif
 566 };
 567
 568 static struct svc_stat          nlmsvc_stats;
 569
 570 #define NLM_NRVERS      ARRAY_SIZE(nlmsvc_version)
 571 static struct svc_program       nlmsvc_program = {
 572         .pg_prog                = NLM_PROGRAM,          /* program number */
 573         .pg_nvers               = NLM_NRVERS,           /* number of entries in nlmsvc_version */
 574         .pg_vers                = nlmsvc_version,       /* version table */
 575         .pg_name                = "lockd",              /* service name */
 576         .pg_class               = "nfsd",               /* share authentication with nfsd */
 577         .pg_stats               = &nlmsvc_stats,        /* stats table */
 578         .pg_authenticate = &lockd_authenticate  /* export authentication */
 579 };