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/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/lockd/sm_inter.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(nlmsvc_ops);
  48
  49 static DEFINE_MUTEX(nlmsvc_mutex);
  50 static unsigned int             nlmsvc_users;
  51 static pid_t                    nlmsvc_pid;
  52 static struct svc_serv          *nlmsvc_serv;
  53 int                             nlmsvc_grace_period;
  54 unsigned long                   nlmsvc_timeout;
  55
  56 static DECLARE_COMPLETION(lockd_start_done);
  57 static DECLARE_WAIT_QUEUE_HEAD(lockd_exit);
  58
  59 /*
  60  * These can be set at insmod time (useful for NFS as root filesystem),
  61  * and also changed through the sysctl interface.  -- Jamie Lokier, Aug 2003
  62  */
  63 static unsigned long            nlm_grace_period;
  64 static unsigned long            nlm_timeout = LOCKD_DFLT_TIMEO;
  65 static int                      nlm_udpport, nlm_tcpport;
  66 int                             nsm_use_hostnames = 0;
  67
  68 /*
  69  * Constants needed for the sysctl interface.
  70  */
  71 static const unsigned long      nlm_grace_period_min = 0;
  72 static const unsigned long      nlm_grace_period_max = 240;
  73 static const unsigned long      nlm_timeout_min = 3;
  74 static const unsigned long      nlm_timeout_max = 20;
  75 static const int                nlm_port_min = 0, nlm_port_max = 65535;
  76
  77 static struct ctl_table_header * nlm_sysctl_table;
  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 unsigned long get_nfs_grace_period(void)
  89 {
  90         unsigned long lockdgrace = get_lockd_grace_period();
  91         unsigned long nfsdgrace = 0;
  92
  93         if (nlmsvc_ops)
  94                 nfsdgrace = nlmsvc_ops->get_grace_period();
  95
  96         return max(lockdgrace, nfsdgrace);
  97 }
  98 EXPORT_SYMBOL(get_nfs_grace_period);
  99
 100 static unsigned long set_grace_period(void)
 101 {
 102         nlmsvc_grace_period = 1;
 103         return get_nfs_grace_period() + jiffies;
 104 }
 105
 106 static inline void clear_grace_period(void)
 107 {
 108         nlmsvc_grace_period = 0;
 109 }
 110
 111 /*
 112  * This is the lockd kernel thread
 113  */
 114 static void
 115 lockd(struct svc_rqst *rqstp)
 116 {
 117         int             err = 0;
 118         unsigned long grace_period_expire;
 119
 120         /* Lock module and set up kernel thread */
 121         /* lockd_up is waiting for us to startup, so will
 122          * be holding a reference to this module, so it
 123          * is safe to just claim another reference
 124          */
 125         __module_get(THIS_MODULE);
 126         lock_kernel();
 127
 128         /*
 129          * Let our maker know we're running.
 130          */
 131         nlmsvc_pid = current->pid;
 132         nlmsvc_serv = rqstp->rq_server;
 133         complete(&lockd_start_done);
 134
 135         daemonize("lockd");
 136         set_freezable();
 137
 138         /* Process request with signals blocked, but allow SIGKILL.  */
 139         allow_signal(SIGKILL);
 140
 141         dprintk("NFS locking service started (ver " LOCKD_VERSION ").\n");
 142
 143         if (!nlm_timeout)
 144                 nlm_timeout = LOCKD_DFLT_TIMEO;
 145         nlmsvc_timeout = nlm_timeout * HZ;
 146
 147         grace_period_expire = 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, and we've been sent a
 152          * signal, or else another process has taken over our job.
 153          */
 154         while ((nlmsvc_users || !signalled()) && nlmsvc_pid == current->pid) {
 155                 long timeout = MAX_SCHEDULE_TIMEOUT;
 156                 char buf[RPC_MAX_ADDRBUFLEN];
 157
 158                 if (signalled()) {
 159                         flush_signals(current);
 160                         if (nlmsvc_ops) {
 161                                 nlmsvc_invalidate_all();
 162                                 grace_period_expire = set_grace_period();
 163                         }
 164                 }
 165
 166                 /*
 167                  * Retry any blocked locks that have been notified by
 168                  * the VFS. Don't do this during grace period.
 169                  * (Theoretically, there shouldn't even be blocked locks
 170                  * during grace period).
 171                  */
 172                 if (!nlmsvc_grace_period) {
 173                         timeout = nlmsvc_retry_blocked();
 174                 } else if (time_before(grace_period_expire, jiffies))
 175                         clear_grace_period();
 176
 177                 /*
 178                  * Find a socket with data available and call its
 179                  * recvfrom routine.
 180                  */
 181                 err = svc_recv(rqstp, timeout);
 182                 if (err == -EAGAIN || err == -EINTR)
 183                         continue;
 184                 if (err < 0) {
 185                         printk(KERN_WARNING
 186                                "lockd: terminating on error %d\n",
 187                                -err);
 188                         break;
 189                 }
 190
 191                 dprintk("lockd: request from %s\n",
 192                                 svc_print_addr(rqstp, buf, sizeof(buf)));
 193
 194                 svc_process(rqstp);
 195         }
 196
 197         flush_signals(current);
 198
 199         /*
 200          * Check whether there's a new lockd process before
 201          * shutting down the hosts and clearing the slot.
 202          */
 203         if (!nlmsvc_pid || current->pid == nlmsvc_pid) {
 204                 if (nlmsvc_ops)
 205                         nlmsvc_invalidate_all();
 206                 nlm_shutdown_hosts();
 207                 nlmsvc_pid = 0;
 208                 nlmsvc_serv = NULL;
 209         } else
 210                 printk(KERN_DEBUG
 211                         "lockd: new process, skipping host shutdown\n");
 212         wake_up(&lockd_exit);
 213
 214         /* Exit the RPC thread */
 215         svc_exit_thread(rqstp);
 216
 217         /* Release module */
 218         unlock_kernel();
 219         module_put_and_exit(0);
 220 }
 221
 222 /*
 223  * Make any sockets that are needed but not present.
 224  * If nlm_udpport or nlm_tcpport were set as module
 225  * options, make those sockets unconditionally
 226  */
 227 static int make_socks(struct svc_serv *serv, int proto)
 228 {
 229         static int warned;
 230         int err = 0;
 231
 232         if (proto == IPPROTO_UDP || nlm_udpport)
 233                 if (!svc_find_xprt(serv, "udp", 0, 0))
 234                         err = svc_create_xprt(serv, "udp", nlm_udpport,
 235                                               SVC_SOCK_DEFAULTS);
 236         if (err >= 0 && (proto == IPPROTO_TCP || nlm_tcpport))
 237                 if (!svc_find_xprt(serv, "tcp", 0, 0))
 238                         err = svc_create_xprt(serv, "tcp", nlm_tcpport,
 239                                               SVC_SOCK_DEFAULTS);
 240
 241         if (err >= 0) {
 242                 warned = 0;
 243                 err = 0;
 244         } else if (warned++ == 0)
 245                 printk(KERN_WARNING
 246                        "lockd_up: makesock failed, error=%d\n", err);
 247         return err;
 248 }
 249
 250 /*
 251  * Bring up the lockd process if it's not already up.
 252  */
 253 int
 254 lockd_up(int proto) /* Maybe add a 'family' option when IPv6 is supported ?? */
 255 {
 256         struct svc_serv *       serv;
 257         int                     error = 0;
 258
 259         mutex_lock(&nlmsvc_mutex);
 260         /*
 261          * Check whether we're already up and running.
 262          */
 263         if (nlmsvc_pid) {
 264                 if (proto)
 265                         error = make_socks(nlmsvc_serv, proto);
 266                 goto out;
 267         }
 268
 269         /*
 270          * Sanity check: if there's no pid,
 271          * we should be the first user ...
 272          */
 273         if (nlmsvc_users)
 274                 printk(KERN_WARNING
 275                         "lockd_up: no pid, %d users??\n", nlmsvc_users);
 276
 277         error = -ENOMEM;
 278         serv = svc_create(&nlmsvc_program, LOCKD_BUFSIZE, NULL);
 279         if (!serv) {
 280                 printk(KERN_WARNING "lockd_up: create service failed\n");
 281                 goto out;
 282         }
 283
 284         if ((error = make_socks(serv, proto)) < 0)
 285                 goto destroy_and_out;
 286
 287         /*
 288          * Create the kernel thread and wait for it to start.
 289          */
 290         error = svc_create_thread(lockd, serv);
 291         if (error) {
 292                 printk(KERN_WARNING
 293                         "lockd_up: create thread failed, error=%d\n", error);
 294                 goto destroy_and_out;
 295         }
 296         wait_for_completion(&lockd_start_done);
 297
 298         /*
 299          * Note: svc_serv structures have an initial use count of 1,
 300          * so we exit through here on both success and failure.
 301          */
 302 destroy_and_out:
 303         svc_destroy(serv);
 304 out:
 305         if (!error)
 306                 nlmsvc_users++;
 307         mutex_unlock(&nlmsvc_mutex);
 308         return error;
 309 }
 310 EXPORT_SYMBOL(lockd_up);
 311
 312 /*
 313  * Decrement the user count and bring down lockd if we're the last.
 314  */
 315 void
 316 lockd_down(void)
 317 {
 318         static int warned;
 319
 320         mutex_lock(&nlmsvc_mutex);
 321         if (nlmsvc_users) {
 322                 if (--nlmsvc_users)
 323                         goto out;
 324         } else
 325                 printk(KERN_WARNING "lockd_down: no users! pid=%d\n", nlmsvc_pid);
 326
 327         if (!nlmsvc_pid) {
 328                 if (warned++ == 0)
 329                         printk(KERN_WARNING "lockd_down: no lockd running.\n");
 330                 goto out;
 331         }
 332         warned = 0;
 333
 334         kill_proc(nlmsvc_pid, SIGKILL, 1);
 335         /*
 336          * Wait for the lockd process to exit, but since we're holding
 337          * the lockd semaphore, we can't wait around forever ...
 338          */
 339         clear_thread_flag(TIF_SIGPENDING);
 340         interruptible_sleep_on_timeout(&lockd_exit, HZ);
 341         if (nlmsvc_pid) {
 342                 printk(KERN_WARNING
 343                         "lockd_down: lockd failed to exit, clearing pid\n");
 344                 nlmsvc_pid = 0;
 345         }
 346         spin_lock_irq(&current->sighand->siglock);
 347         recalc_sigpending();
 348         spin_unlock_irq(&current->sighand->siglock);
 349 out:
 350         mutex_unlock(&nlmsvc_mutex);
 351 }
 352 EXPORT_SYMBOL(lockd_down);
 353
 354 /*
 355  * Sysctl parameters (same as module parameters, different interface).
 356  */
 357
 358 static ctl_table nlm_sysctls[] = {
 359         {
 360                 .ctl_name       = CTL_UNNUMBERED,
 361                 .procname       = "nlm_grace_period",
 362                 .data           = &nlm_grace_period,
 363                 .maxlen         = sizeof(unsigned long),
 364                 .mode           = 0644,
 365                 .proc_handler   = &proc_doulongvec_minmax,
 366                 .extra1         = (unsigned long *) &nlm_grace_period_min,
 367                 .extra2         = (unsigned long *) &nlm_grace_period_max,
 368         },
 369         {
 370                 .ctl_name       = CTL_UNNUMBERED,
 371                 .procname       = "nlm_timeout",
 372                 .data           = &nlm_timeout,
 373                 .maxlen         = sizeof(unsigned long),
 374                 .mode           = 0644,
 375                 .proc_handler   = &proc_doulongvec_minmax,
 376                 .extra1         = (unsigned long *) &nlm_timeout_min,
 377                 .extra2         = (unsigned long *) &nlm_timeout_max,
 378         },
 379         {
 380                 .ctl_name       = CTL_UNNUMBERED,
 381                 .procname       = "nlm_udpport",
 382                 .data           = &nlm_udpport,
 383                 .maxlen         = sizeof(int),
 384                 .mode           = 0644,
 385                 .proc_handler   = &proc_dointvec_minmax,
 386                 .extra1         = (int *) &nlm_port_min,
 387                 .extra2         = (int *) &nlm_port_max,
 388         },
 389         {
 390                 .ctl_name       = CTL_UNNUMBERED,
 391                 .procname       = "nlm_tcpport",
 392                 .data           = &nlm_tcpport,
 393                 .maxlen         = sizeof(int),
 394                 .mode           = 0644,
 395                 .proc_handler   = &proc_dointvec_minmax,
 396                 .extra1         = (int *) &nlm_port_min,
 397                 .extra2         = (int *) &nlm_port_max,
 398         },
 399         {
 400                 .ctl_name       = CTL_UNNUMBERED,
 401                 .procname       = "nsm_use_hostnames",
 402                 .data           = &nsm_use_hostnames,
 403                 .maxlen         = sizeof(int),
 404                 .mode           = 0644,
 405                 .proc_handler   = &proc_dointvec,
 406         },
 407         {
 408                 .ctl_name       = CTL_UNNUMBERED,
 409                 .procname       = "nsm_local_state",
 410                 .data           = &nsm_local_state,
 411                 .maxlen         = sizeof(int),
 412                 .mode           = 0644,
 413                 .proc_handler   = &proc_dointvec,
 414         },
 415         { .ctl_name = 0 }
 416 };
 417
 418 static ctl_table nlm_sysctl_dir[] = {
 419         {
 420                 .ctl_name       = CTL_UNNUMBERED,
 421                 .procname       = "nfs",
 422                 .mode           = 0555,
 423                 .child          = nlm_sysctls,
 424         },
 425         { .ctl_name = 0 }
 426 };
 427
 428 static ctl_table nlm_sysctl_root[] = {
 429         {
 430                 .ctl_name       = CTL_FS,
 431                 .procname       = "fs",
 432                 .mode           = 0555,
 433                 .child          = nlm_sysctl_dir,
 434         },
 435         { .ctl_name = 0 }
 436 };
 437
 438 /*
 439  * Module (and sysfs) parameters.
 440  */
 441
 442 #define param_set_min_max(name, type, which_strtol, min, max)           \
 443 static int param_set_##name(const char *val, struct kernel_param *kp)   \
 444 {                                                                       \
 445         char *endp;                                                     \
 446         __typeof__(type) num = which_strtol(val, &endp, 0);             \
 447         if (endp == val || *endp || num < (min) || num > (max))         \
 448                 return -EINVAL;                                         \
 449         *((int *) kp->arg) = num;                                       \
 450         return 0;                                                       \
 451 }
 452
 453 static inline int is_callback(u32 proc)
 454 {
 455         return proc == NLMPROC_GRANTED
 456                 || proc == NLMPROC_GRANTED_MSG
 457                 || proc == NLMPROC_TEST_RES
 458                 || proc == NLMPROC_LOCK_RES
 459                 || proc == NLMPROC_CANCEL_RES
 460                 || proc == NLMPROC_UNLOCK_RES
 461                 || proc == NLMPROC_NSM_NOTIFY;
 462 }
 463
 464
 465 static int lockd_authenticate(struct svc_rqst *rqstp)
 466 {
 467         rqstp->rq_client = NULL;
 468         switch (rqstp->rq_authop->flavour) {
 469                 case RPC_AUTH_NULL:
 470                 case RPC_AUTH_UNIX:
 471                         if (rqstp->rq_proc == 0)
 472                                 return SVC_OK;
 473                         if (is_callback(rqstp->rq_proc)) {
 474                                 /* Leave it to individual procedures to
 475                                  * call nlmsvc_lookup_host(rqstp)
 476                                  */
 477                                 return SVC_OK;
 478                         }
 479                         return svc_set_client(rqstp);
 480         }
 481         return SVC_DENIED;
 482 }
 483
 484
 485 param_set_min_max(port, int, simple_strtol, 0, 65535)
 486 param_set_min_max(grace_period, unsigned long, simple_strtoul,
 487                   nlm_grace_period_min, nlm_grace_period_max)
 488 param_set_min_max(timeout, unsigned long, simple_strtoul,
 489                   nlm_timeout_min, nlm_timeout_max)
 490
 491 MODULE_AUTHOR("Olaf Kirch <okir@monad.swb.de>");
 492 MODULE_DESCRIPTION("NFS file locking service version " LOCKD_VERSION ".");
 493 MODULE_LICENSE("GPL");
 494
 495 module_param_call(nlm_grace_period, param_set_grace_period, param_get_ulong,
 496                   &nlm_grace_period, 0644);
 497 module_param_call(nlm_timeout, param_set_timeout, param_get_ulong,
 498                   &nlm_timeout, 0644);
 499 module_param_call(nlm_udpport, param_set_port, param_get_int,
 500                   &nlm_udpport, 0644);
 501 module_param_call(nlm_tcpport, param_set_port, param_get_int,
 502                   &nlm_tcpport, 0644);
 503 module_param(nsm_use_hostnames, bool, 0644);
 504
 505 /*
 506  * Initialising and terminating the module.
 507  */
 508
 509 static int __init init_nlm(void)
 510 {
 511         nlm_sysctl_table = register_sysctl_table(nlm_sysctl_root);
 512         return nlm_sysctl_table ? 0 : -ENOMEM;
 513 }
 514
 515 static void __exit exit_nlm(void)
 516 {
 517         /* FIXME: delete all NLM clients */
 518         nlm_shutdown_hosts();
 519         unregister_sysctl_table(nlm_sysctl_table);
 520 }
 521
 522 module_init(init_nlm);
 523 module_exit(exit_nlm);
 524
 525 /*
 526  * Define NLM program and procedures
 527  */
 528 static struct svc_version       nlmsvc_version1 = {
 529                 .vs_vers        = 1,
 530                 .vs_nproc       = 17,
 531                 .vs_proc        = nlmsvc_procedures,
 532                 .vs_xdrsize     = NLMSVC_XDRSIZE,
 533 };
 534 static struct svc_version       nlmsvc_version3 = {
 535                 .vs_vers        = 3,
 536                 .vs_nproc       = 24,
 537                 .vs_proc        = nlmsvc_procedures,
 538                 .vs_xdrsize     = NLMSVC_XDRSIZE,
 539 };
 540 #ifdef CONFIG_LOCKD_V4
 541 static struct svc_version       nlmsvc_version4 = {
 542                 .vs_vers        = 4,
 543                 .vs_nproc       = 24,
 544                 .vs_proc        = nlmsvc_procedures4,
 545                 .vs_xdrsize     = NLMSVC_XDRSIZE,
 546 };
 547 #endif
 548 static struct svc_version *     nlmsvc_version[] = {
 549         [1] = &nlmsvc_version1,
 550         [3] = &nlmsvc_version3,
 551 #ifdef CONFIG_LOCKD_V4
 552         [4] = &nlmsvc_version4,
 553 #endif
 554 };
 555
 556 static struct svc_stat          nlmsvc_stats;
 557
 558 #define NLM_NRVERS      ARRAY_SIZE(nlmsvc_version)
 559 static struct svc_program       nlmsvc_program = {
 560         .pg_prog                = NLM_PROGRAM,          /* program number */
 561         .pg_nvers               = NLM_NRVERS,           /* number of entries in nlmsvc_version */
 562         .pg_vers                = nlmsvc_version,       /* version table */
 563         .pg_name                = "lockd",              /* service name */
 564         .pg_class               = "nfsd",               /* share authentication with nfsd */
 565         .pg_stats               = &nlmsvc_stats,        /* stats table */
 566         .pg_authenticate = &lockd_authenticate  /* export authentication */
 567 };