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