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_serv          *nlmsvc_serv;
  54 int                             nlmsvc_grace_period;
  55 unsigned long                   nlmsvc_timeout;
  56
  57 /*
  58  * These can be set at insmod time (useful for NFS as root filesystem),
  59  * and also changed through the sysctl interface.  -- Jamie Lokier, Aug 2003
  60  */
  61 static unsigned long            nlm_grace_period;
  62 static unsigned long            nlm_timeout = LOCKD_DFLT_TIMEO;
  63 static int                      nlm_udpport, nlm_tcpport;
  64 int                             nsm_use_hostnames = 0;
  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 static struct ctl_table_header * nlm_sysctl_table;
  76
  77 static unsigned long get_lockd_grace_period(void)
  78 {
  79         /* Note: nlm_timeout should always be nonzero */
  80         if (nlm_grace_period)
  81                 return roundup(nlm_grace_period, nlm_timeout) * HZ;
  82         else
  83                 return nlm_timeout * 5 * HZ;
  84 }
  85
  86 unsigned long get_nfs_grace_period(void)
  87 {
  88         unsigned long lockdgrace = get_lockd_grace_period();
  89         unsigned long nfsdgrace = 0;
  90
  91         if (nlmsvc_ops)
  92                 nfsdgrace = nlmsvc_ops->get_grace_period();
  93
  94         return max(lockdgrace, nfsdgrace);
  95 }
  96 EXPORT_SYMBOL(get_nfs_grace_period);
  97
  98 static unsigned long set_grace_period(void)
  99 {
 100         nlmsvc_grace_period = 1;
 101         return get_nfs_grace_period() + jiffies;
 102 }
 103
 104 static inline void clear_grace_period(void)
 105 {
 106         nlmsvc_grace_period = 0;
 107 }
 108
 109 /*
 110  * This is the lockd kernel thread
 111  */
 112 static int
 113 lockd(void *vrqstp)
 114 {
 115         int             err = 0;
 116         struct svc_rqst *rqstp = vrqstp;
 117         unsigned long grace_period_expire;
 118
 119         /* try_to_freeze() is called from svc_recv() */
 120         set_freezable();
 121
 122         /* Allow SIGKILL to tell lockd to drop all of its locks */
 123         allow_signal(SIGKILL);
 124
 125         dprintk("NFS locking service started (ver " LOCKD_VERSION ").\n");
 126
 127         /*
 128          * FIXME: it would be nice if lockd didn't spend its entire life
 129          * running under the BKL. At the very least, it would be good to
 130          * have someone clarify what it's intended to protect here. I've
 131          * seen some handwavy posts about posix locking needing to be
 132          * done under the BKL, but it's far from clear.
 133          */
 134         lock_kernel();
 135
 136         if (!nlm_timeout)
 137                 nlm_timeout = LOCKD_DFLT_TIMEO;
 138         nlmsvc_timeout = nlm_timeout * HZ;
 139
 140         grace_period_expire = set_grace_period();
 141
 142         /*
 143          * The main request loop. We don't terminate until the last
 144          * NFS mount or NFS daemon has gone away.
 145          */
 146         while (!kthread_should_stop()) {
 147                 long timeout = MAX_SCHEDULE_TIMEOUT;
 148                 RPC_IFDEBUG(char buf[RPC_MAX_ADDRBUFLEN]);
 149
 150                 if (signalled()) {
 151                         flush_signals(current);
 152                         if (nlmsvc_ops) {
 153                                 nlmsvc_invalidate_all();
 154                                 grace_period_expire = set_grace_period();
 155                         }
 156                         continue;
 157                 }
 158
 159                 /*
 160                  * Retry any blocked locks that have been notified by
 161                  * the VFS. Don't do this during grace period.
 162                  * (Theoretically, there shouldn't even be blocked locks
 163                  * during grace period).
 164                  */
 165                 if (!nlmsvc_grace_period) {
 166                         timeout = nlmsvc_retry_blocked();
 167                 } else if (time_before(grace_period_expire, jiffies))
 168                         clear_grace_period();
 169
 170                 /*
 171                  * Find a socket with data available and call its
 172                  * recvfrom routine.
 173                  */
 174                 err = svc_recv(rqstp, timeout);
 175                 if (err == -EAGAIN || err == -EINTR)
 176                         continue;
 177                 if (err < 0) {
 178                         printk(KERN_WARNING
 179                                "lockd: terminating on error %d\n",
 180                                -err);
 181                         break;
 182                 }
 183
 184                 dprintk("lockd: request from %s\n",
 185                                 svc_print_addr(rqstp, buf, sizeof(buf)));
 186
 187                 svc_process(rqstp);
 188         }
 189
 190         flush_signals(current);
 191         if (nlmsvc_ops)
 192                 nlmsvc_invalidate_all();
 193         nlm_shutdown_hosts();
 194
 195         unlock_kernel();
 196
 197         nlmsvc_task = NULL;
 198         nlmsvc_serv = NULL;
 199
 200         /* Exit the RPC thread */
 201         svc_exit_thread(rqstp);
 202
 203         return 0;
 204 }
 205
 206 /*
 207  * Make any sockets that are needed but not present.
 208  * If nlm_udpport or nlm_tcpport were set as module
 209  * options, make those sockets unconditionally
 210  */
 211 static int make_socks(struct svc_serv *serv, int proto)
 212 {
 213         static int warned;
 214         struct svc_xprt *xprt;
 215         int err = 0;
 216
 217         if (proto == IPPROTO_UDP || nlm_udpport) {
 218                 xprt = svc_find_xprt(serv, "udp", 0, 0);
 219                 if (!xprt)
 220                         err = svc_create_xprt(serv, "udp", nlm_udpport,
 221                                               SVC_SOCK_DEFAULTS);
 222                 else
 223                         svc_xprt_put(xprt);
 224         }
 225         if (err >= 0 && (proto == IPPROTO_TCP || nlm_tcpport)) {
 226                 xprt = svc_find_xprt(serv, "tcp", 0, 0);
 227                 if (!xprt)
 228                         err = svc_create_xprt(serv, "tcp", nlm_tcpport,
 229                                               SVC_SOCK_DEFAULTS);
 230                 else
 231                         svc_xprt_put(xprt);
 232         }
 233         if (err >= 0) {
 234                 warned = 0;
 235                 err = 0;
 236         } else if (warned++ == 0)
 237                 printk(KERN_WARNING
 238                        "lockd_up: makesock failed, error=%d\n", err);
 239         return err;
 240 }
 241
 242 /*
 243  * Bring up the lockd process if it's not already up.
 244  */
 245 int
 246 lockd_up(int proto) /* Maybe add a 'family' option when IPv6 is supported ?? */
 247 {
 248         struct svc_serv *serv;
 249         struct svc_rqst *rqstp;
 250         int             error = 0;
 251
 252         mutex_lock(&nlmsvc_mutex);
 253         /*
 254          * Check whether we're already up and running.
 255          */
 256         if (nlmsvc_serv) {
 257                 if (proto)
 258                         error = make_socks(nlmsvc_serv, proto);
 259                 goto out;
 260         }
 261
 262         /*
 263          * Sanity check: if there's no pid,
 264          * we should be the first user ...
 265          */
 266         if (nlmsvc_users)
 267                 printk(KERN_WARNING
 268                         "lockd_up: no pid, %d users??\n", nlmsvc_users);
 269
 270         error = -ENOMEM;
 271         serv = svc_create(&nlmsvc_program, LOCKD_BUFSIZE, NULL);
 272         if (!serv) {
 273                 printk(KERN_WARNING "lockd_up: create service failed\n");
 274                 goto out;
 275         }
 276
 277         if ((error = make_socks(serv, proto)) < 0)
 278                 goto destroy_and_out;
 279
 280         /*
 281          * Create the kernel thread and wait for it to start.
 282          */
 283         rqstp = svc_prepare_thread(serv, &serv->sv_pools[0]);
 284         if (IS_ERR(rqstp)) {
 285                 error = PTR_ERR(rqstp);
 286                 printk(KERN_WARNING
 287                         "lockd_up: svc_rqst allocation failed, error=%d\n",
 288                         error);
 289                 goto destroy_and_out;
 290         }
 291
 292         svc_sock_update_bufs(serv);
 293         nlmsvc_serv = rqstp->rq_server;
 294
 295         nlmsvc_task = kthread_run(lockd, rqstp, serv->sv_name);
 296         if (IS_ERR(nlmsvc_task)) {
 297                 error = PTR_ERR(nlmsvc_task);
 298                 nlmsvc_task = NULL;
 299                 nlmsvc_serv = NULL;
 300                 printk(KERN_WARNING
 301                         "lockd_up: kthread_run failed, error=%d\n", error);
 302                 svc_exit_thread(rqstp);
 303                 goto destroy_and_out;
 304         }
 305
 306         /*
 307          * Note: svc_serv structures have an initial use count of 1,
 308          * so we exit through here on both success and failure.
 309          */
 310 destroy_and_out:
 311         svc_destroy(serv);
 312 out:
 313         if (!error)
 314                 nlmsvc_users++;
 315         mutex_unlock(&nlmsvc_mutex);
 316         return error;
 317 }
 318 EXPORT_SYMBOL(lockd_up);
 319
 320 /*
 321  * Decrement the user count and bring down lockd if we're the last.
 322  */
 323 void
 324 lockd_down(void)
 325 {
 326         mutex_lock(&nlmsvc_mutex);
 327         if (nlmsvc_users) {
 328                 if (--nlmsvc_users)
 329                         goto out;
 330         } else {
 331                 printk(KERN_ERR "lockd_down: no users! task=%p\n",
 332                         nlmsvc_task);
 333                 BUG();
 334         }
 335
 336         if (!nlmsvc_task) {
 337                 printk(KERN_ERR "lockd_down: no lockd running.\n");
 338                 BUG();
 339         }
 340         kthread_stop(nlmsvc_task);
 341 out:
 342         mutex_unlock(&nlmsvc_mutex);
 343 }
 344 EXPORT_SYMBOL(lockd_down);
 345
 346 /*
 347  * Sysctl parameters (same as module parameters, different interface).
 348  */
 349
 350 static ctl_table nlm_sysctls[] = {
 351         {
 352                 .ctl_name       = CTL_UNNUMBERED,
 353                 .procname       = "nlm_grace_period",
 354                 .data           = &nlm_grace_period,
 355                 .maxlen         = sizeof(unsigned long),
 356                 .mode           = 0644,
 357                 .proc_handler   = &proc_doulongvec_minmax,
 358                 .extra1         = (unsigned long *) &nlm_grace_period_min,
 359                 .extra2         = (unsigned long *) &nlm_grace_period_max,
 360         },
 361         {
 362                 .ctl_name       = CTL_UNNUMBERED,
 363                 .procname       = "nlm_timeout",
 364                 .data           = &nlm_timeout,
 365                 .maxlen         = sizeof(unsigned long),
 366                 .mode           = 0644,
 367                 .proc_handler   = &proc_doulongvec_minmax,
 368                 .extra1         = (unsigned long *) &nlm_timeout_min,
 369                 .extra2         = (unsigned long *) &nlm_timeout_max,
 370         },
 371         {
 372                 .ctl_name       = CTL_UNNUMBERED,
 373                 .procname       = "nlm_udpport",
 374                 .data           = &nlm_udpport,
 375                 .maxlen         = sizeof(int),
 376                 .mode           = 0644,
 377                 .proc_handler   = &proc_dointvec_minmax,
 378                 .extra1         = (int *) &nlm_port_min,
 379                 .extra2         = (int *) &nlm_port_max,
 380         },
 381         {
 382                 .ctl_name       = CTL_UNNUMBERED,
 383                 .procname       = "nlm_tcpport",
 384                 .data           = &nlm_tcpport,
 385                 .maxlen         = sizeof(int),
 386                 .mode           = 0644,
 387                 .proc_handler   = &proc_dointvec_minmax,
 388                 .extra1         = (int *) &nlm_port_min,
 389                 .extra2         = (int *) &nlm_port_max,
 390         },
 391         {
 392                 .ctl_name       = CTL_UNNUMBERED,
 393                 .procname       = "nsm_use_hostnames",
 394                 .data           = &nsm_use_hostnames,
 395                 .maxlen         = sizeof(int),
 396                 .mode           = 0644,
 397                 .proc_handler   = &proc_dointvec,
 398         },
 399         {
 400                 .ctl_name       = CTL_UNNUMBERED,
 401                 .procname       = "nsm_local_state",
 402                 .data           = &nsm_local_state,
 403                 .maxlen         = sizeof(int),
 404                 .mode           = 0644,
 405                 .proc_handler   = &proc_dointvec,
 406         },
 407         { .ctl_name = 0 }
 408 };
 409
 410 static ctl_table nlm_sysctl_dir[] = {
 411         {
 412                 .ctl_name       = CTL_UNNUMBERED,
 413                 .procname       = "nfs",
 414                 .mode           = 0555,
 415                 .child          = nlm_sysctls,
 416         },
 417         { .ctl_name = 0 }
 418 };
 419
 420 static ctl_table nlm_sysctl_root[] = {
 421         {
 422                 .ctl_name       = CTL_FS,
 423                 .procname       = "fs",
 424                 .mode           = 0555,
 425                 .child          = nlm_sysctl_dir,
 426         },
 427         { .ctl_name = 0 }
 428 };
 429
 430 /*
 431  * Module (and sysfs) parameters.
 432  */
 433
 434 #define param_set_min_max(name, type, which_strtol, min, max)           \
 435 static int param_set_##name(const char *val, struct kernel_param *kp)   \
 436 {                                                                       \
 437         char *endp;                                                     \
 438         __typeof__(type) num = which_strtol(val, &endp, 0);             \
 439         if (endp == val || *endp || num < (min) || num > (max))         \
 440                 return -EINVAL;                                         \
 441         *((int *) kp->arg) = num;                                       \
 442         return 0;                                                       \
 443 }
 444
 445 static inline int is_callback(u32 proc)
 446 {
 447         return proc == NLMPROC_GRANTED
 448                 || proc == NLMPROC_GRANTED_MSG
 449                 || proc == NLMPROC_TEST_RES
 450                 || proc == NLMPROC_LOCK_RES
 451                 || proc == NLMPROC_CANCEL_RES
 452                 || proc == NLMPROC_UNLOCK_RES
 453                 || proc == NLMPROC_NSM_NOTIFY;
 454 }
 455
 456
 457 static int lockd_authenticate(struct svc_rqst *rqstp)
 458 {
 459         rqstp->rq_client = NULL;
 460         switch (rqstp->rq_authop->flavour) {
 461                 case RPC_AUTH_NULL:
 462                 case RPC_AUTH_UNIX:
 463                         if (rqstp->rq_proc == 0)
 464                                 return SVC_OK;
 465                         if (is_callback(rqstp->rq_proc)) {
 466                                 /* Leave it to individual procedures to
 467                                  * call nlmsvc_lookup_host(rqstp)
 468                                  */
 469                                 return SVC_OK;
 470                         }
 471                         return svc_set_client(rqstp);
 472         }
 473         return SVC_DENIED;
 474 }
 475
 476
 477 param_set_min_max(port, int, simple_strtol, 0, 65535)
 478 param_set_min_max(grace_period, unsigned long, simple_strtoul,
 479                   nlm_grace_period_min, nlm_grace_period_max)
 480 param_set_min_max(timeout, unsigned long, simple_strtoul,
 481                   nlm_timeout_min, nlm_timeout_max)
 482
 483 MODULE_AUTHOR("Olaf Kirch <okir@monad.swb.de>");
 484 MODULE_DESCRIPTION("NFS file locking service version " LOCKD_VERSION ".");
 485 MODULE_LICENSE("GPL");
 486
 487 module_param_call(nlm_grace_period, param_set_grace_period, param_get_ulong,
 488                   &nlm_grace_period, 0644);
 489 module_param_call(nlm_timeout, param_set_timeout, param_get_ulong,
 490                   &nlm_timeout, 0644);
 491 module_param_call(nlm_udpport, param_set_port, param_get_int,
 492                   &nlm_udpport, 0644);
 493 module_param_call(nlm_tcpport, param_set_port, param_get_int,
 494                   &nlm_tcpport, 0644);
 495 module_param(nsm_use_hostnames, bool, 0644);
 496
 497 /*
 498  * Initialising and terminating the module.
 499  */
 500
 501 static int __init init_nlm(void)
 502 {
 503         nlm_sysctl_table = register_sysctl_table(nlm_sysctl_root);
 504         return nlm_sysctl_table ? 0 : -ENOMEM;
 505 }
 506
 507 static void __exit exit_nlm(void)
 508 {
 509         /* FIXME: delete all NLM clients */
 510         nlm_shutdown_hosts();
 511         unregister_sysctl_table(nlm_sysctl_table);
 512 }
 513
 514 module_init(init_nlm);
 515 module_exit(exit_nlm);
 516
 517 /*
 518  * Define NLM program and procedures
 519  */
 520 static struct svc_version       nlmsvc_version1 = {
 521                 .vs_vers        = 1,
 522                 .vs_nproc       = 17,
 523                 .vs_proc        = nlmsvc_procedures,
 524                 .vs_xdrsize     = NLMSVC_XDRSIZE,
 525 };
 526 static struct svc_version       nlmsvc_version3 = {
 527                 .vs_vers        = 3,
 528                 .vs_nproc       = 24,
 529                 .vs_proc        = nlmsvc_procedures,
 530                 .vs_xdrsize     = NLMSVC_XDRSIZE,
 531 };
 532 #ifdef CONFIG_LOCKD_V4
 533 static struct svc_version       nlmsvc_version4 = {
 534                 .vs_vers        = 4,
 535                 .vs_nproc       = 24,
 536                 .vs_proc        = nlmsvc_procedures4,
 537                 .vs_xdrsize     = NLMSVC_XDRSIZE,
 538 };
 539 #endif
 540 static struct svc_version *     nlmsvc_version[] = {
 541         [1] = &nlmsvc_version1,
 542         [3] = &nlmsvc_version3,
 543 #ifdef CONFIG_LOCKD_V4
 544         [4] = &nlmsvc_version4,
 545 #endif
 546 };
 547
 548 static struct svc_stat          nlmsvc_stats;
 549
 550 #define NLM_NRVERS      ARRAY_SIZE(nlmsvc_version)
 551 static struct svc_program       nlmsvc_program = {
 552         .pg_prog                = NLM_PROGRAM,          /* program number */
 553         .pg_nvers               = NLM_NRVERS,           /* number of entries in nlmsvc_version */
 554         .pg_vers                = nlmsvc_version,       /* version table */
 555         .pg_name                = "lockd",              /* service name */
 556         .pg_class               = "nfsd",               /* share authentication with nfsd */
 557         .pg_stats               = &nlmsvc_stats,        /* stats table */
 558         .pg_authenticate = &lockd_authenticate  /* export authentication */
 559 };