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 #define __KERNEL_SYSCALLS__
  16 #include <linux/config.h>
  17 #include <linux/module.h>
  18 #include <linux/init.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/version.h>
  25 #include <linux/unistd.h>
  26 #include <linux/slab.h>
  27 #include <linux/smp.h>
  28 #include <linux/smp_lock.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 <linux/lockd/lockd.h>
  36 #include <linux/nfs.h>
  37
  38 #define NLMDBG_FACILITY         NLMDBG_SVC
  39 #define LOCKD_BUFSIZE           (1024 + NLMSSVC_XDRSIZE)
  40 #define ALLOWED_SIGS            (sigmask(SIGKILL))
  41
  42 extern struct svc_program       nlmsvc_program;
  43 struct nlmsvc_binding *         nlmsvc_ops;
  44 static DECLARE_MUTEX(nlmsvc_sema);
  45 static unsigned int             nlmsvc_users;
  46 static pid_t                    nlmsvc_pid;
  47 int                             nlmsvc_grace_period;
  48 unsigned long                   nlmsvc_timeout;
  49
  50 static DECLARE_MUTEX_LOCKED(lockd_start);
  51 static DECLARE_WAIT_QUEUE_HEAD(lockd_exit);
  52
  53 /*
  54  * Currently the following can be set only at insmod time.
  55  * Ideally, they would be accessible through the sysctl interface.
  56  */
  57 unsigned long                   nlm_grace_period;
  58 unsigned long                   nlm_timeout = LOCKD_DFLT_TIMEO;
  59 unsigned long                   nlm_udpport, nlm_tcpport;
  60
  61 static unsigned long set_grace_period(void)
  62 {
  63         unsigned long grace_period;
  64
  65         /* Note: nlm_timeout should always be nonzero */
  66         if (nlm_grace_period)
  67                 grace_period = ((nlm_grace_period + nlm_timeout - 1)
  68                                 / nlm_timeout) * nlm_timeout * HZ;
  69         else
  70                 grace_period = nlm_timeout * 5 * HZ;
  71         nlmsvc_grace_period = 1;
  72         return grace_period + jiffies;
  73 }
  74
  75 /*
  76  * This is the lockd kernel thread
  77  */
  78 static void
  79 lockd(struct svc_rqst *rqstp)
  80 {
  81         struct svc_serv *serv = rqstp->rq_server;
  82         int             err = 0;
  83         unsigned long grace_period_expire;
  84
  85         /* Lock module and set up kernel thread */
  86         MOD_INC_USE_COUNT;
  87         lock_kernel();
  88
  89         /*
  90          * Let our maker know we're running.
  91          */
  92         nlmsvc_pid = current->pid;
  93         up(&lockd_start);
  94
  95         daemonize();
  96         reparent_to_init();
  97         sprintf(current->comm, "lockd");
  98
  99         /* Process request with signals blocked.  */
 100         spin_lock_irq(&current->sigmask_lock);
 101         siginitsetinv(&current->blocked, sigmask(SIGKILL));
 102         recalc_sigpending(current);
 103         spin_unlock_irq(&current->sigmask_lock);
 104
 105         /* kick rpciod */
 106         rpciod_up();
 107
 108         dprintk("NFS locking service started (ver " LOCKD_VERSION ").\n");
 109
 110         if (!nlm_timeout)
 111                 nlm_timeout = LOCKD_DFLT_TIMEO;
 112         nlmsvc_timeout = nlm_timeout * HZ;
 113
 114         grace_period_expire = set_grace_period();
 115
 116         /*
 117          * The main request loop. We don't terminate until the last
 118          * NFS mount or NFS daemon has gone away, and we've been sent a
 119          * signal, or else another process has taken over our job.
 120          */
 121         while ((nlmsvc_users || !signalled()) && nlmsvc_pid == current->pid)
 122         {
 123                 long timeout = MAX_SCHEDULE_TIMEOUT;
 124                 if (signalled()) {
 125                         spin_lock_irq(&current->sigmask_lock);
 126                         flush_signals(current);
 127                         spin_unlock_irq(&current->sigmask_lock);
 128                         if (nlmsvc_ops) {
 129                                 nlmsvc_ops->detach();
 130                                 grace_period_expire = set_grace_period();
 131                         }
 132                 }
 133
 134                 /*
 135                  * Retry any blocked locks that have been notified by
 136                  * the VFS. Don't do this during grace period.
 137                  * (Theoretically, there shouldn't even be blocked locks
 138                  * during grace period).
 139                  */
 140                 if (!nlmsvc_grace_period)
 141                         timeout = nlmsvc_retry_blocked();
 142
 143                 /*
 144                  * Find a socket with data available and call its
 145                  * recvfrom routine.
 146                  */
 147                 err = svc_recv(serv, rqstp, timeout);
 148                 if (err == -EAGAIN || err == -EINTR)
 149                         continue;
 150                 if (err < 0) {
 151                         printk(KERN_WARNING
 152                                "lockd: terminating on error %d\n",
 153                                -err);
 154                         break;
 155                 }
 156
 157                 dprintk("lockd: request from %08x\n",
 158                         (unsigned)ntohl(rqstp->rq_addr.sin_addr.s_addr));
 159
 160                 /*
 161                  * Look up the NFS client handle. The handle is needed for
 162                  * all but the GRANTED callback RPCs.
 163                  */
 164                 rqstp->rq_client = NULL;
 165                 if (nlmsvc_ops) {
 166                         nlmsvc_ops->exp_readlock();
 167                         rqstp->rq_client =
 168                                 nlmsvc_ops->exp_getclient(&rqstp->rq_addr);
 169                 }
 170
 171                 if (nlmsvc_grace_period &&
 172                     time_before(grace_period_expire, jiffies))
 173                         nlmsvc_grace_period = 0;
 174                 svc_process(serv, rqstp);
 175
 176                 /* Unlock export hash tables */
 177                 if (nlmsvc_ops)
 178                         nlmsvc_ops->exp_unlock();
 179         }
 180
 181         /*
 182          * Check whether there's a new lockd process before
 183          * shutting down the hosts and clearing the slot.
 184          */
 185         if (!nlmsvc_pid || current->pid == nlmsvc_pid) {
 186                 if (nlmsvc_ops)
 187                         nlmsvc_ops->detach();
 188                 nlm_shutdown_hosts();
 189                 nlmsvc_pid = 0;
 190         } else
 191                 printk(KERN_DEBUG
 192                         "lockd: new process, skipping host shutdown\n");
 193         wake_up(&lockd_exit);
 194
 195         /* Exit the RPC thread */
 196         svc_exit_thread(rqstp);
 197
 198         /* release rpciod */
 199         rpciod_down();
 200
 201         /* Release module */
 202         MOD_DEC_USE_COUNT;
 203 }
 204
 205 /*
 206  * Bring up the lockd process if it's not already up.
 207  */
 208 int
 209 lockd_up(void)
 210 {
 211         static int              warned = 0;
 212         struct svc_serv *       serv;
 213         int                     error = 0;
 214
 215         down(&nlmsvc_sema);
 216         /*
 217          * Unconditionally increment the user count ... this is
 218          * the number of clients who _want_ a lockd process.
 219          */
 220         nlmsvc_users++;
 221         /*
 222          * Check whether we're already up and running.
 223          */
 224         if (nlmsvc_pid)
 225                 goto out;
 226
 227         /*
 228          * Sanity check: if there's no pid,
 229          * we should be the first user ...
 230          */
 231         if (nlmsvc_users > 1)
 232                 printk(KERN_WARNING
 233                         "lockd_up: no pid, %d users??\n", nlmsvc_users);
 234
 235         error = -ENOMEM;
 236         serv = svc_create(&nlmsvc_program, 0, NLMSVC_XDRSIZE);
 237         if (!serv) {
 238                 printk(KERN_WARNING "lockd_up: create service failed\n");
 239                 goto out;
 240         }
 241
 242         if ((error = svc_makesock(serv, IPPROTO_UDP, nlm_udpport)) < 0
 243 #ifdef CONFIG_NFSD_TCP
 244          || (error = svc_makesock(serv, IPPROTO_TCP, nlm_tcpport)) < 0
 245 #endif
 246                 ) {
 247                 if (warned++ == 0)
 248                         printk(KERN_WARNING
 249                                 "lockd_up: makesock failed, error=%d\n", error);
 250                 goto destroy_and_out;
 251         }
 252         warned = 0;
 253
 254         /*
 255          * Create the kernel thread and wait for it to start.
 256          */
 257         error = svc_create_thread(lockd, serv);
 258         if (error) {
 259                 printk(KERN_WARNING
 260                         "lockd_up: create thread failed, error=%d\n", error);
 261                 goto destroy_and_out;
 262         }
 263         down(&lockd_start);
 264
 265         /*
 266          * Note: svc_serv structures have an initial use count of 1,
 267          * so we exit through here on both success and failure.
 268          */
 269 destroy_and_out:
 270         svc_destroy(serv);
 271 out:
 272         up(&nlmsvc_sema);
 273         return error;
 274 }
 275
 276 /*
 277  * Decrement the user count and bring down lockd if we're the last.
 278  */
 279 void
 280 lockd_down(void)
 281 {
 282         static int warned = 0;
 283
 284         down(&nlmsvc_sema);
 285         if (nlmsvc_users) {
 286                 if (--nlmsvc_users)
 287                         goto out;
 288         } else
 289                 printk(KERN_WARNING "lockd_down: no users! pid=%d\n", nlmsvc_pid);
 290
 291         if (!nlmsvc_pid) {
 292                 if (warned++ == 0)
 293                         printk(KERN_WARNING "lockd_down: no lockd running.\n");
 294                 goto out;
 295         }
 296         warned = 0;
 297
 298         kill_proc(nlmsvc_pid, SIGKILL, 1);
 299         /*
 300          * Wait for the lockd process to exit, but since we're holding
 301          * the lockd semaphore, we can't wait around forever ...
 302          */
 303         current->sigpending = 0;
 304         interruptible_sleep_on_timeout(&lockd_exit, HZ);
 305         if (nlmsvc_pid) {
 306                 printk(KERN_WARNING
 307                         "lockd_down: lockd failed to exit, clearing pid\n");
 308                 nlmsvc_pid = 0;
 309         }
 310         spin_lock_irq(&current->sigmask_lock);
 311         recalc_sigpending(current);
 312         spin_unlock_irq(&current->sigmask_lock);
 313 out:
 314         up(&nlmsvc_sema);
 315 }
 316
 317 #ifdef MODULE
 318 /* New module support in 2.1.18 */
 319
 320 MODULE_AUTHOR("Olaf Kirch <okir@monad.swb.de>");
 321 MODULE_DESCRIPTION("NFS file locking service version " LOCKD_VERSION ".");
 322 MODULE_LICENSE("GPL");
 323 MODULE_PARM(nlm_grace_period, "10-240l");
 324 MODULE_PARM(nlm_timeout, "3-20l");
 325 MODULE_PARM(nlm_udpport, "0-65535l");
 326 MODULE_PARM(nlm_tcpport, "0-65535l");
 327
 328 int
 329 init_module(void)
 330 {
 331         /* Init the static variables */
 332         init_MUTEX(&nlmsvc_sema);
 333         nlmsvc_users = 0;
 334         nlmsvc_pid = 0;
 335         return 0;
 336 }
 337
 338 void
 339 cleanup_module(void)
 340 {
 341         /* FIXME: delete all NLM clients */
 342         nlm_shutdown_hosts();
 343 }
 344 #else
 345 /* not a module, so process bootargs
 346  * lockd.udpport and lockd.tcpport
 347  */
 348
 349 static int __init udpport_set(char *str)
 350 {
 351         nlm_udpport = simple_strtoul(str, NULL, 0);
 352         return 1;
 353 }
 354 static int __init tcpport_set(char *str)
 355 {
 356         nlm_tcpport = simple_strtoul(str, NULL, 0);
 357         return 1;
 358 }
 359 __setup("lockd.udpport=", udpport_set);
 360 __setup("lockd.tcpport=", tcpport_set);
 361
 362 #endif
 363
 364 /*
 365  * Define NLM program and procedures
 366  */
 367 static struct svc_version       nlmsvc_version1 = {
 368         1, 17, nlmsvc_procedures, NULL
 369 };
 370 static struct svc_version       nlmsvc_version3 = {
 371         3, 24, nlmsvc_procedures, NULL
 372 };
 373 #ifdef CONFIG_LOCKD_V4
 374 static struct svc_version       nlmsvc_version4 = {
 375         4, 24, nlmsvc_procedures4, NULL
 376 };
 377 #endif
 378 static struct svc_version *     nlmsvc_version[] = {
 379         NULL,
 380         &nlmsvc_version1,
 381         NULL,
 382         &nlmsvc_version3,
 383 #ifdef CONFIG_LOCKD_V4
 384         &nlmsvc_version4,
 385 #endif
 386 };
 387
 388 static struct svc_stat          nlmsvc_stats;
 389
 390 #define NLM_NRVERS      (sizeof(nlmsvc_version)/sizeof(nlmsvc_version[0]))
 391 struct svc_program              nlmsvc_program = {
 392         NLM_PROGRAM,            /* program number */
 393         1, NLM_NRVERS-1,        /* version range */
 394         NLM_NRVERS,             /* number of entries in nlmsvc_version */
 395         nlmsvc_version,         /* version table */
 396         "lockd",                /* service name */
 397         &nlmsvc_stats,          /* stats table */
 398 };