fs/lockd/clntproc.c

   1 /*
   2  * linux/fs/lockd/clntproc.c
   3  *
   4  * RPC procedures for the client side NLM implementation
   5  *
   6  * Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de>
   7  */
   8
   9 #include <linux/types.h>
  10 #include <linux/errno.h>
  11 #include <linux/fs.h>
  12 #include <linux/nfs_fs.h>
  13 #include <linux/utsname.h>
  14 #include <linux/smp_lock.h>
  15 #include <linux/sunrpc/clnt.h>
  16 #include <linux/sunrpc/svc.h>
  17 #include <linux/lockd/lockd.h>
  18 #include <linux/lockd/sm_inter.h>
  19
  20 #define NLMDBG_FACILITY         NLMDBG_CLIENT
  21
  22 static int      nlmclnt_test(struct nlm_rqst *, struct file_lock *);
  23 static int      nlmclnt_lock(struct nlm_rqst *, struct file_lock *);
  24 static int      nlmclnt_unlock(struct nlm_rqst *, struct file_lock *);
  25 static void     nlmclnt_unlock_callback(struct rpc_task *);
  26 static void     nlmclnt_cancel_callback(struct rpc_task *);
  27 static int      nlm_stat_to_errno(u32 stat);
  28
  29 /*
  30  * Cookie counter for NLM requests
  31  */
  32 static u32      nlm_cookie = 0x1234;
  33
  34 static inline void nlmclnt_next_cookie(struct nlm_cookie *c)
  35 {
  36         memcpy(c->data, &nlm_cookie, 4);
  37         memset(c->data+4, 0, 4);
  38         c->len=4;
  39         nlm_cookie++;
  40 }
  41
  42 /*
  43  * Initialize arguments for TEST/LOCK/UNLOCK/CANCEL calls
  44  */
  45 static inline void
  46 nlmclnt_setlockargs(struct nlm_rqst *req, struct file_lock *fl)
  47 {
  48         struct nlm_args *argp = &req->a_args;
  49         struct nlm_lock *lock = &argp->lock;
  50
  51         nlmclnt_next_cookie(&argp->cookie);
  52         argp->state   = nsm_local_state;
  53         memcpy(&lock->fh, NFS_FH(fl->fl_file->f_dentry->d_inode), sizeof(struct nfs_fh));
  54         lock->caller  = system_utsname.nodename;
  55         lock->oh.data = req->a_owner;
  56         lock->oh.len  = sprintf(req->a_owner, "%d@%s",
  57                                 current->pid, system_utsname.nodename);
  58         locks_copy_lock(&lock->fl, fl);
  59 }
  60
  61 /*
  62  * Initialize arguments for GRANTED call. The nlm_rqst structure
  63  * has been cleared already.
  64  */
  65 int
  66 nlmclnt_setgrantargs(struct nlm_rqst *call, struct nlm_lock *lock)
  67 {
  68         locks_copy_lock(&call->a_args.lock.fl, &lock->fl);
  69         memcpy(&call->a_args.lock.fh, &lock->fh, sizeof(call->a_args.lock.fh));
  70         call->a_args.lock.caller = system_utsname.nodename;
  71         call->a_args.lock.oh.len = lock->oh.len;
  72
  73         /* set default data area */
  74         call->a_args.lock.oh.data = call->a_owner;
  75
  76         if (lock->oh.len > NLMCLNT_OHSIZE) {
  77                 void *data = kmalloc(lock->oh.len, GFP_KERNEL);
  78                 if (!data)
  79                         return 0;
  80                 call->a_args.lock.oh.data = (u8 *) data;
  81         }
  82
  83         memcpy(call->a_args.lock.oh.data, lock->oh.data, lock->oh.len);
  84         return 1;
  85 }
  86
  87 void
  88 nlmclnt_freegrantargs(struct nlm_rqst *call)
  89 {
  90         /*
  91          * Check whether we allocated memory for the owner.
  92          */
  93         if (call->a_args.lock.oh.data != (u8 *) call->a_owner) {
  94                 kfree(call->a_args.lock.oh.data);
  95         }
  96 }
  97
  98 /*
  99  * This is the main entry point for the NLM client.
 100  */
 101 int
 102 nlmclnt_proc(struct inode *inode, int cmd, struct file_lock *fl)
 103 {
 104         struct nfs_server       *nfssrv = NFS_SERVER(inode);
 105         struct nlm_host         *host;
 106         struct nlm_rqst         reqst, *call = &reqst;
 107         sigset_t                oldset;
 108         unsigned long           flags;
 109         int                     status, proto, vers;
 110
 111         vers = (NFS_PROTO(inode)->version == 3) ? 4 : 1;
 112         if (NFS_PROTO(inode)->version > 3) {
 113                 printk(KERN_NOTICE "NFSv4 file locking not implemented!\n");
 114                 return -ENOLCK;
 115         }
 116
 117         /* Retrieve transport protocol from NFS client */
 118         proto = NFS_CLIENT(inode)->cl_xprt->prot;
 119
 120         if (!(host = nlmclnt_lookup_host(NFS_ADDR(inode), proto, vers)))
 121                 return -ENOLCK;
 122
 123         /* Create RPC client handle if not there, and copy soft
 124          * and intr flags from NFS client. */
 125         if (host->h_rpcclnt == NULL) {
 126                 struct rpc_clnt *clnt;
 127
 128                 /* Bind an rpc client to this host handle (does not
 129                  * perform a portmapper lookup) */
 130                 if (!(clnt = nlm_bind_host(host))) {
 131                         status = -ENOLCK;
 132                         goto done;
 133                 }
 134                 clnt->cl_softrtry = nfssrv->client->cl_softrtry;
 135                 clnt->cl_intr     = nfssrv->client->cl_intr;
 136                 clnt->cl_chatty   = nfssrv->client->cl_chatty;
 137         }
 138
 139         /* Keep the old signal mask */
 140         spin_lock_irqsave(&current->sigmask_lock, flags);
 141         oldset = current->blocked;
 142
 143         /* If we're cleaning up locks because the process is exiting,
 144          * perform the RPC call asynchronously. */
 145         if ((cmd == F_SETLK || cmd == F_SETLKW)
 146             && fl->fl_type == F_UNLCK
 147             && (current->flags & PF_EXITING)) {
 148                 sigfillset(&current->blocked);  /* Mask all signals */
 149                 recalc_sigpending(current);
 150                 spin_unlock_irqrestore(&current->sigmask_lock, flags);
 151
 152                 call = nlmclnt_alloc_call();
 153                 if (!call) {
 154                         status = -ENOMEM;
 155                         goto out_restore;
 156                 }
 157                 call->a_flags = RPC_TASK_ASYNC;
 158         } else {
 159                 spin_unlock_irqrestore(&current->sigmask_lock, flags);
 160                 memset(call, 0, sizeof(*call));
 161                 locks_init_lock(&call->a_args.lock.fl);
 162                 locks_init_lock(&call->a_res.lock.fl);
 163         }
 164         call->a_host = host;
 165
 166         /* Set up the argument struct */
 167         nlmclnt_setlockargs(call, fl);
 168
 169         if (cmd == F_GETLK) {
 170                 status = nlmclnt_test(call, fl);
 171         } else if ((cmd == F_SETLK || cmd == F_SETLKW)
 172                    && fl->fl_type == F_UNLCK) {
 173                 status = nlmclnt_unlock(call, fl);
 174         } else if (cmd == F_SETLK || cmd == F_SETLKW) {
 175                 call->a_args.block = (cmd == F_SETLKW)? 1 : 0;
 176                 status = nlmclnt_lock(call, fl);
 177         } else {
 178                 status = -EINVAL;
 179         }
 180
 181         if (status < 0 && (call->a_flags & RPC_TASK_ASYNC))
 182                 kfree(call);
 183
 184  out_restore:
 185         spin_lock_irqsave(&current->sigmask_lock, flags);
 186         current->blocked = oldset;
 187         recalc_sigpending(current);
 188         spin_unlock_irqrestore(&current->sigmask_lock, flags);
 189
 190 done:
 191         dprintk("lockd: clnt proc returns %d\n", status);
 192         nlm_release_host(host);
 193         return status;
 194 }
 195
 196 /*
 197  * Wait while server is in grace period
 198  */
 199 static inline int
 200 nlmclnt_grace_wait(struct nlm_host *host)
 201 {
 202         if (!host->h_reclaiming)
 203                 interruptible_sleep_on_timeout(&host->h_gracewait, 10*HZ);
 204         else
 205                 interruptible_sleep_on(&host->h_gracewait);
 206         return signalled()? -ERESTARTSYS : 0;
 207 }
 208
 209 /*
 210  * Allocate an NLM RPC call struct
 211  */
 212 struct nlm_rqst *
 213 nlmclnt_alloc_call(void)
 214 {
 215         struct nlm_rqst *call;
 216
 217         while (!signalled()) {
 218                 call = (struct nlm_rqst *) kmalloc(sizeof(struct nlm_rqst), GFP_KERNEL);
 219                 if (call) {
 220                         memset(call, 0, sizeof(*call));
 221                         locks_init_lock(&call->a_args.lock.fl);
 222                         locks_init_lock(&call->a_res.lock.fl);
 223                         return call;
 224                 }
 225                 printk("nlmclnt_alloc_call: failed, waiting for memory\n");
 226                 current->state = TASK_INTERRUPTIBLE;
 227                 schedule_timeout(5*HZ);
 228         }
 229         return NULL;
 230 }
 231
 232 /*
 233  * Generic NLM call
 234  */
 235 int
 236 nlmclnt_call(struct nlm_rqst *req, u32 proc)
 237 {
 238         struct nlm_host *host = req->a_host;
 239         struct rpc_clnt *clnt;
 240         struct nlm_args *argp = &req->a_args;
 241         struct nlm_res  *resp = &req->a_res;
 242         struct file     *filp = argp->lock.fl.fl_file;
 243         struct rpc_message msg;
 244         int             status;
 245
 246         dprintk("lockd: call procedure %s on %s\n",
 247                         nlm_procname(proc), host->h_name);
 248
 249         msg.rpc_proc = proc;
 250         msg.rpc_argp = argp;
 251         msg.rpc_resp = resp;
 252         if (filp)
 253                 msg.rpc_cred = nfs_file_cred(filp);
 254         else
 255                 msg.rpc_cred = NULL;
 256
 257         do {
 258                 if (host->h_reclaiming && !argp->reclaim) {
 259                         interruptible_sleep_on(&host->h_gracewait);
 260                         continue;
 261                 }
 262
 263                 /* If we have no RPC client yet, create one. */
 264                 if ((clnt = nlm_bind_host(host)) == NULL)
 265                         return -ENOLCK;
 266
 267                 /* Perform the RPC call. If an error occurs, try again */
 268                 if ((status = rpc_call_sync(clnt, &msg, 0)) < 0) {
 269                         dprintk("lockd: rpc_call returned error %d\n", -status);
 270                         switch (status) {
 271                         case -EPROTONOSUPPORT:
 272                                 status = -EINVAL;
 273                                 break;
 274                         case -ECONNREFUSED:
 275                         case -ETIMEDOUT:
 276                         case -ENOTCONN:
 277                                 nlm_rebind_host(host);
 278                                 status = -EAGAIN;
 279                                 break;
 280                         case -ERESTARTSYS:
 281                                 return signalled () ? -EINTR : status;
 282                         default:
 283                                 break;
 284                         }
 285                         break;
 286                 } else
 287                 if (resp->status == NLM_LCK_DENIED_GRACE_PERIOD) {
 288                         dprintk("lockd: server in grace period\n");
 289                         if (argp->reclaim) {
 290                                 printk(KERN_WARNING
 291                                      "lockd: spurious grace period reject?!\n");
 292                                 return -ENOLCK;
 293                         }
 294                 } else {
 295                         dprintk("lockd: server returns status %d\n", resp->status);
 296                         return 0;       /* Okay, call complete */
 297                 }
 298
 299                 /* Back off a little and try again */
 300                 interruptible_sleep_on_timeout(&host->h_gracewait, 15*HZ);
 301
 302                 /* When the lock requested by F_SETLKW isn't available,
 303                    we will wait until the request can be satisfied. If
 304                    a signal is received during wait, we should return
 305                    -EINTR. */
 306                 if (signalled ()) {
 307                         status = -EINTR;
 308                         break;
 309                 }
 310         } while (1);
 311
 312         return status;
 313 }
 314
 315 /*
 316  * Generic NLM call, async version.
 317  */
 318 int
 319 nlmsvc_async_call(struct nlm_rqst *req, u32 proc, rpc_action callback)
 320 {
 321         struct nlm_host *host = req->a_host;
 322         struct rpc_clnt *clnt;
 323         struct nlm_args *argp = &req->a_args;
 324         struct nlm_res  *resp = &req->a_res;
 325         struct rpc_message msg;
 326         int             status;
 327
 328         dprintk("lockd: call procedure %s on %s (async)\n",
 329                         nlm_procname(proc), host->h_name);
 330
 331         /* If we have no RPC client yet, create one. */
 332         if ((clnt = nlm_bind_host(host)) == NULL)
 333                 return -ENOLCK;
 334
 335         /* bootstrap and kick off the async RPC call */
 336         msg.rpc_proc = proc;
 337         msg.rpc_argp = argp;
 338         msg.rpc_resp =resp;
 339         msg.rpc_cred = NULL;
 340         status = rpc_call_async(clnt, &msg, RPC_TASK_ASYNC, callback, req);
 341
 342         return status;
 343 }
 344
 345 int
 346 nlmclnt_async_call(struct nlm_rqst *req, u32 proc, rpc_action callback)
 347 {
 348         struct nlm_host *host = req->a_host;
 349         struct rpc_clnt *clnt;
 350         struct nlm_args *argp = &req->a_args;
 351         struct nlm_res  *resp = &req->a_res;
 352         struct file     *file = argp->lock.fl.fl_file;
 353         struct rpc_message msg;
 354         int             status;
 355
 356         dprintk("lockd: call procedure %s on %s (async)\n",
 357                         nlm_procname(proc), host->h_name);
 358
 359         /* If we have no RPC client yet, create one. */
 360         if ((clnt = nlm_bind_host(host)) == NULL)
 361                 return -ENOLCK;
 362
 363         /* bootstrap and kick off the async RPC call */
 364         msg.rpc_proc = proc;
 365         msg.rpc_argp = argp;
 366         msg.rpc_resp =resp;
 367         if (file)
 368                 msg.rpc_cred = nfs_file_cred(file);
 369         else
 370                 msg.rpc_cred = NULL;
 371         /* Increment host refcount */
 372         nlm_get_host(host);
 373         status = rpc_call_async(clnt, &msg, RPC_TASK_ASYNC, callback, req);
 374         if (status < 0)
 375                 nlm_release_host(host);
 376         return status;
 377 }
 378
 379 /*
 380  * TEST for the presence of a conflicting lock
 381  */
 382 static int
 383 nlmclnt_test(struct nlm_rqst *req, struct file_lock *fl)
 384 {
 385         int     status;
 386
 387         if ((status = nlmclnt_call(req, NLMPROC_TEST)) < 0)
 388                 return status;
 389
 390         status = req->a_res.status;
 391         if (status == NLM_LCK_GRANTED) {
 392                 fl->fl_type = F_UNLCK;
 393         } if (status == NLM_LCK_DENIED) {
 394                 /*
 395                  * Report the conflicting lock back to the application.
 396                  * FIXME: Is it OK to report the pid back as well?
 397                  */
 398                 locks_copy_lock(fl, &req->a_res.lock.fl);
 399                 /* fl->fl_pid = 0; */
 400         } else {
 401                 return nlm_stat_to_errno(req->a_res.status);
 402         }
 403
 404         return 0;
 405 }
 406
 407 static
 408 void nlmclnt_insert_lock_callback(struct file_lock *fl)
 409 {
 410         nlm_get_host(fl->fl_u.nfs_fl.host);
 411 }
 412 static
 413 void nlmclnt_remove_lock_callback(struct file_lock *fl)
 414 {
 415         if (fl->fl_u.nfs_fl.host) {
 416                 nlm_release_host(fl->fl_u.nfs_fl.host);
 417                 fl->fl_u.nfs_fl.host = NULL;
 418         }
 419 }
 420
 421 /*
 422  * LOCK: Try to create a lock
 423  *
 424  *                      Programmer Harassment Alert
 425  *
 426  * When given a blocking lock request in a sync RPC call, the HPUX lockd
 427  * will faithfully return LCK_BLOCKED but never cares to notify us when
 428  * the lock could be granted. This way, our local process could hang
 429  * around forever waiting for the callback.
 430  *
 431  *  Solution A: Implement busy-waiting
 432  *  Solution B: Use the async version of the call (NLM_LOCK_{MSG,RES})
 433  *
 434  * For now I am implementing solution A, because I hate the idea of
 435  * re-implementing lockd for a third time in two months. The async
 436  * calls shouldn't be too hard to do, however.
 437  *
 438  * This is one of the lovely things about standards in the NFS area:
 439  * they're so soft and squishy you can't really blame HP for doing this.
 440  */
 441 static int
 442 nlmclnt_lock(struct nlm_rqst *req, struct file_lock *fl)
 443 {
 444         struct nlm_host *host = req->a_host;
 445         struct nlm_res  *resp = &req->a_res;
 446         int             status;
 447
 448         if (!host->h_monitored && nsm_monitor(host) < 0) {
 449                 printk(KERN_NOTICE "lockd: failed to monitor %s\n",
 450                                         host->h_name);
 451                 return -ENOLCK;
 452         }
 453
 454         do {
 455                 if ((status = nlmclnt_call(req, NLMPROC_LOCK)) >= 0) {
 456                         if (resp->status != NLM_LCK_BLOCKED)
 457                                 break;
 458                         status = nlmclnt_block(host, fl, &resp->status);
 459                 }
 460                 if (status < 0)
 461                         return status;
 462         } while (resp->status == NLM_LCK_BLOCKED);
 463
 464         if (resp->status == NLM_LCK_GRANTED) {
 465                 fl->fl_u.nfs_fl.state = host->h_state;
 466                 fl->fl_u.nfs_fl.flags |= NFS_LCK_GRANTED;
 467                 fl->fl_u.nfs_fl.host = host;
 468                 fl->fl_insert = nlmclnt_insert_lock_callback;
 469                 fl->fl_remove = nlmclnt_remove_lock_callback;
 470         }
 471
 472         return nlm_stat_to_errno(resp->status);
 473 }
 474
 475 /*
 476  * RECLAIM: Try to reclaim a lock
 477  */
 478 int
 479 nlmclnt_reclaim(struct nlm_host *host, struct file_lock *fl)
 480 {
 481         struct nlm_rqst reqst, *req;
 482         int             status;
 483
 484         req = &reqst;
 485         memset(req, 0, sizeof(*req));
 486         locks_init_lock(&req->a_args.lock.fl);
 487         locks_init_lock(&req->a_res.lock.fl);
 488         req->a_host  = host;
 489         req->a_flags = 0;
 490
 491         /* Set up the argument struct */
 492         nlmclnt_setlockargs(req, fl);
 493         req->a_args.reclaim = 1;
 494
 495         if ((status = nlmclnt_call(req, NLMPROC_LOCK)) >= 0
 496          && req->a_res.status == NLM_LCK_GRANTED)
 497                 return 0;
 498
 499         printk(KERN_WARNING "lockd: failed to reclaim lock for pid %d "
 500                                 "(errno %d, status %d)\n", fl->fl_pid,
 501                                 status, req->a_res.status);
 502
 503         /*
 504          * FIXME: This is a serious failure. We can
 505          *
 506          *  a.  Ignore the problem
 507          *  b.  Send the owning process some signal (Linux doesn't have
 508          *      SIGLOST, though...)
 509          *  c.  Retry the operation
 510          *
 511          * Until someone comes up with a simple implementation
 512          * for b or c, I'll choose option a.
 513          */
 514
 515         return -ENOLCK;
 516 }
 517
 518 /*
 519  * UNLOCK: remove an existing lock
 520  */
 521 static int
 522 nlmclnt_unlock(struct nlm_rqst *req, struct file_lock *fl)
 523 {
 524         struct nlm_res  *resp = &req->a_res;
 525         int             status;
 526
 527         /* Clean the GRANTED flag now so the lock doesn't get
 528          * reclaimed while we're stuck in the unlock call. */
 529         fl->fl_u.nfs_fl.flags &= ~NFS_LCK_GRANTED;
 530
 531         if (req->a_flags & RPC_TASK_ASYNC) {
 532                 return nlmclnt_async_call(req, NLMPROC_UNLOCK,
 533                                         nlmclnt_unlock_callback);
 534         }
 535
 536         if ((status = nlmclnt_call(req, NLMPROC_UNLOCK)) < 0)
 537                 return status;
 538
 539         if (resp->status == NLM_LCK_GRANTED)
 540                 return 0;
 541
 542         if (resp->status != NLM_LCK_DENIED_NOLOCKS)
 543                 printk("lockd: unexpected unlock status: %d\n", resp->status);
 544
 545         /* What to do now? I'm out of my depth... */
 546
 547         return -ENOLCK;
 548 }
 549
 550 static void
 551 nlmclnt_unlock_callback(struct rpc_task *task)
 552 {
 553         struct nlm_rqst *req = (struct nlm_rqst *) task->tk_calldata;
 554         int             status = req->a_res.status;
 555
 556         if (RPC_ASSASSINATED(task))
 557                 goto die;
 558
 559         if (task->tk_status < 0) {
 560                 dprintk("lockd: unlock failed (err = %d)\n", -task->tk_status);
 561                 goto retry_unlock;
 562         }
 563         if (status != NLM_LCK_GRANTED
 564          && status != NLM_LCK_DENIED_GRACE_PERIOD) {
 565                 printk("lockd: unexpected unlock status: %d\n", status);
 566         }
 567
 568 die:
 569         nlm_release_host(req->a_host);
 570         kfree(req);
 571         return;
 572  retry_unlock:
 573         nlm_rebind_host(req->a_host);
 574         rpc_restart_call(task);
 575 }
 576
 577 /*
 578  * Cancel a blocked lock request.
 579  * We always use an async RPC call for this in order not to hang a
 580  * process that has been Ctrl-C'ed.
 581  */
 582 int
 583 nlmclnt_cancel(struct nlm_host *host, struct file_lock *fl)
 584 {
 585         struct nlm_rqst *req;
 586         unsigned long   flags;
 587         sigset_t        oldset;
 588         int             status;
 589
 590         /* Block all signals while setting up call */
 591         spin_lock_irqsave(&current->sigmask_lock, flags);
 592         oldset = current->blocked;
 593         sigfillset(&current->blocked);
 594         recalc_sigpending(current);
 595         spin_unlock_irqrestore(&current->sigmask_lock, flags);
 596
 597         req = nlmclnt_alloc_call();
 598         if (!req)
 599                 return -ENOMEM;
 600         req->a_host  = host;
 601         req->a_flags = RPC_TASK_ASYNC;
 602
 603         nlmclnt_setlockargs(req, fl);
 604
 605         status = nlmclnt_async_call(req, NLMPROC_CANCEL,
 606                                         nlmclnt_cancel_callback);
 607         if (status < 0)
 608                 kfree(req);
 609
 610         spin_lock_irqsave(&current->sigmask_lock, flags);
 611         current->blocked = oldset;
 612         recalc_sigpending(current);
 613         spin_unlock_irqrestore(&current->sigmask_lock, flags);
 614
 615         return status;
 616 }
 617
 618 static void
 619 nlmclnt_cancel_callback(struct rpc_task *task)
 620 {
 621         struct nlm_rqst *req = (struct nlm_rqst *) task->tk_calldata;
 622
 623         if (RPC_ASSASSINATED(task))
 624                 goto die;
 625
 626         if (task->tk_status < 0) {
 627                 dprintk("lockd: CANCEL call error %d, retrying.\n",
 628                                         task->tk_status);
 629                 goto retry_cancel;
 630         }
 631
 632         dprintk("lockd: cancel status %d (task %d)\n",
 633                         req->a_res.status, task->tk_pid);
 634
 635         switch (req->a_res.status) {
 636         case NLM_LCK_GRANTED:
 637         case NLM_LCK_DENIED_GRACE_PERIOD:
 638                 /* Everything's good */
 639                 break;
 640         case NLM_LCK_DENIED_NOLOCKS:
 641                 dprintk("lockd: CANCEL failed (server has no locks)\n");
 642                 goto retry_cancel;
 643         default:
 644                 printk(KERN_NOTICE "lockd: weird return %d for CANCEL call\n",
 645                         req->a_res.status);
 646         }
 647
 648 die:
 649         nlm_release_host(req->a_host);
 650         kfree(req);
 651         return;
 652
 653 retry_cancel:
 654         nlm_rebind_host(req->a_host);
 655         rpc_restart_call(task);
 656         rpc_delay(task, 30 * HZ);
 657 }
 658
 659 /*
 660  * Convert an NLM status code to a generic kernel errno
 661  */
 662 static int
 663 nlm_stat_to_errno(u32 status)
 664 {
 665         switch(status) {
 666         case NLM_LCK_GRANTED:
 667                 return 0;
 668         case NLM_LCK_DENIED:
 669                 return -EAGAIN;
 670         case NLM_LCK_DENIED_NOLOCKS:
 671         case NLM_LCK_DENIED_GRACE_PERIOD:
 672                 return -ENOLCK;
 673         case NLM_LCK_BLOCKED:
 674                 printk(KERN_NOTICE "lockd: unexpected status NLM_BLOCKED\n");
 675                 return -ENOLCK;
 676         }
 677         printk(KERN_NOTICE "lockd: unexpected server status %d\n", status);
 678         return -ENOLCK;
 679 }