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