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/config.h>
  10 #include <linux/module.h>
  11 #include <linux/types.h>
  12 #include <linux/errno.h>
  13 #include <linux/fs.h>
  14 #include <linux/nfs_fs.h>
  15 #include <linux/utsname.h>
  16 #include <linux/smp_lock.h>
  17 #include <linux/sunrpc/clnt.h>
  18 #include <linux/sunrpc/svc.h>
  19 #include <linux/lockd/lockd.h>
  20 #include <linux/lockd/sm_inter.h>
  21
  22 #define NLMDBG_FACILITY         NLMDBG_CLIENT
  23 #define NLMCLNT_GRACE_WAIT      (5*HZ)
  24 #define NLMCLNT_POLL_TIMEOUT    (30*HZ)
  25 #define NLMCLNT_MAX_RETRIES     3
  26
  27 static int      nlmclnt_test(struct nlm_rqst *, struct file_lock *);
  28 static int      nlmclnt_lock(struct nlm_rqst *, struct file_lock *);
  29 static int      nlmclnt_unlock(struct nlm_rqst *, struct file_lock *);
  30 static int      nlm_stat_to_errno(u32 stat);
  31 static void     nlmclnt_locks_init_private(struct file_lock *fl, struct nlm_host *host);
  32 static int      nlmclnt_cancel(struct nlm_host *, int , struct file_lock *);
  33
  34 static const struct rpc_call_ops nlmclnt_unlock_ops;
  35 static const struct rpc_call_ops nlmclnt_cancel_ops;
  36
  37 /*
  38  * Cookie counter for NLM requests
  39  */
  40 static u32      nlm_cookie = 0x1234;
  41
  42 static inline void nlmclnt_next_cookie(struct nlm_cookie *c)
  43 {
  44         memcpy(c->data, &nlm_cookie, 4);
  45         memset(c->data+4, 0, 4);
  46         c->len=4;
  47         nlm_cookie++;
  48 }
  49
  50 static struct nlm_lockowner *nlm_get_lockowner(struct nlm_lockowner *lockowner)
  51 {
  52         atomic_inc(&lockowner->count);
  53         return lockowner;
  54 }
  55
  56 static void nlm_put_lockowner(struct nlm_lockowner *lockowner)
  57 {
  58         if (!atomic_dec_and_lock(&lockowner->count, &lockowner->host->h_lock))
  59                 return;
  60         list_del(&lockowner->list);
  61         spin_unlock(&lockowner->host->h_lock);
  62         nlm_release_host(lockowner->host);
  63         kfree(lockowner);
  64 }
  65
  66 static inline int nlm_pidbusy(struct nlm_host *host, uint32_t pid)
  67 {
  68         struct nlm_lockowner *lockowner;
  69         list_for_each_entry(lockowner, &host->h_lockowners, list) {
  70                 if (lockowner->pid == pid)
  71                         return -EBUSY;
  72         }
  73         return 0;
  74 }
  75
  76 static inline uint32_t __nlm_alloc_pid(struct nlm_host *host)
  77 {
  78         uint32_t res;
  79         do {
  80                 res = host->h_pidcount++;
  81         } while (nlm_pidbusy(host, res) < 0);
  82         return res;
  83 }
  84
  85 static struct nlm_lockowner *__nlm_find_lockowner(struct nlm_host *host, fl_owner_t owner)
  86 {
  87         struct nlm_lockowner *lockowner;
  88         list_for_each_entry(lockowner, &host->h_lockowners, list) {
  89                 if (lockowner->owner != owner)
  90                         continue;
  91                 return nlm_get_lockowner(lockowner);
  92         }
  93         return NULL;
  94 }
  95
  96 static struct nlm_lockowner *nlm_find_lockowner(struct nlm_host *host, fl_owner_t owner)
  97 {
  98         struct nlm_lockowner *res, *new = NULL;
  99
 100         spin_lock(&host->h_lock);
 101         res = __nlm_find_lockowner(host, owner);
 102         if (res == NULL) {
 103                 spin_unlock(&host->h_lock);
 104                 new = (struct nlm_lockowner *)kmalloc(sizeof(*new), GFP_KERNEL);
 105                 spin_lock(&host->h_lock);
 106                 res = __nlm_find_lockowner(host, owner);
 107                 if (res == NULL && new != NULL) {
 108                         res = new;
 109                         atomic_set(&new->count, 1);
 110                         new->owner = owner;
 111                         new->pid = __nlm_alloc_pid(host);
 112                         new->host = nlm_get_host(host);
 113                         list_add(&new->list, &host->h_lockowners);
 114                         new = NULL;
 115                 }
 116         }
 117         spin_unlock(&host->h_lock);
 118         kfree(new);
 119         return res;
 120 }
 121
 122 /*
 123  * Initialize arguments for TEST/LOCK/UNLOCK/CANCEL calls
 124  */
 125 static void nlmclnt_setlockargs(struct nlm_rqst *req, struct file_lock *fl)
 126 {
 127         struct nlm_args *argp = &req->a_args;
 128         struct nlm_lock *lock = &argp->lock;
 129
 130         nlmclnt_next_cookie(&argp->cookie);
 131         argp->state   = nsm_local_state;
 132         memcpy(&lock->fh, NFS_FH(fl->fl_file->f_dentry->d_inode), sizeof(struct nfs_fh));
 133         lock->caller  = system_utsname.nodename;
 134         lock->oh.data = req->a_owner;
 135         lock->oh.len  = snprintf(req->a_owner, sizeof(req->a_owner), "%u@%s",
 136                                 (unsigned int)fl->fl_u.nfs_fl.owner->pid,
 137                                 system_utsname.nodename);
 138         lock->svid = fl->fl_u.nfs_fl.owner->pid;
 139         lock->fl.fl_start = fl->fl_start;
 140         lock->fl.fl_end = fl->fl_end;
 141         lock->fl.fl_type = fl->fl_type;
 142 }
 143
 144 static void nlmclnt_release_lockargs(struct nlm_rqst *req)
 145 {
 146         BUG_ON(req->a_args.lock.fl.fl_ops != NULL);
 147 }
 148
 149 /*
 150  * This is the main entry point for the NLM client.
 151  */
 152 int
 153 nlmclnt_proc(struct inode *inode, int cmd, struct file_lock *fl)
 154 {
 155         struct nlm_host         *host;
 156         struct nlm_rqst         *call;
 157         sigset_t                oldset;
 158         unsigned long           flags;
 159         int                     status, proto, vers;
 160
 161         vers = (NFS_PROTO(inode)->version == 3) ? 4 : 1;
 162         if (NFS_PROTO(inode)->version > 3) {
 163                 printk(KERN_NOTICE "NFSv4 file locking not implemented!\n");
 164                 return -ENOLCK;
 165         }
 166
 167         /* Retrieve transport protocol from NFS client */
 168         proto = NFS_CLIENT(inode)->cl_xprt->prot;
 169
 170         host = nlmclnt_lookup_host(NFS_ADDR(inode), proto, vers);
 171         if (host == NULL)
 172                 return -ENOLCK;
 173
 174         call = nlm_alloc_call(host);
 175         if (call == NULL)
 176                 return -ENOMEM;
 177
 178         nlmclnt_locks_init_private(fl, host);
 179         /* Set up the argument struct */
 180         nlmclnt_setlockargs(call, fl);
 181
 182         /* Keep the old signal mask */
 183         spin_lock_irqsave(&current->sighand->siglock, flags);
 184         oldset = current->blocked;
 185
 186         /* If we're cleaning up locks because the process is exiting,
 187          * perform the RPC call asynchronously. */
 188         if ((IS_SETLK(cmd) || IS_SETLKW(cmd))
 189             && fl->fl_type == F_UNLCK
 190             && (current->flags & PF_EXITING)) {
 191                 sigfillset(&current->blocked);  /* Mask all signals */
 192                 recalc_sigpending();
 193
 194                 call->a_flags = RPC_TASK_ASYNC;
 195         }
 196         spin_unlock_irqrestore(&current->sighand->siglock, flags);
 197
 198         if (IS_SETLK(cmd) || IS_SETLKW(cmd)) {
 199                 if (fl->fl_type != F_UNLCK) {
 200                         call->a_args.block = IS_SETLKW(cmd) ? 1 : 0;
 201                         status = nlmclnt_lock(call, fl);
 202                 } else
 203                         status = nlmclnt_unlock(call, fl);
 204         } else if (IS_GETLK(cmd))
 205                 status = nlmclnt_test(call, fl);
 206         else
 207                 status = -EINVAL;
 208
 209         fl->fl_ops->fl_release_private(fl);
 210         fl->fl_ops = NULL;
 211
 212         spin_lock_irqsave(&current->sighand->siglock, flags);
 213         current->blocked = oldset;
 214         recalc_sigpending();
 215         spin_unlock_irqrestore(&current->sighand->siglock, flags);
 216
 217         dprintk("lockd: clnt proc returns %d\n", status);
 218         return status;
 219 }
 220 EXPORT_SYMBOL(nlmclnt_proc);
 221
 222 /*
 223  * Allocate an NLM RPC call struct
 224  *
 225  * Note: the caller must hold a reference to host. In case of failure,
 226  * this reference will be released.
 227  */
 228 struct nlm_rqst *nlm_alloc_call(struct nlm_host *host)
 229 {
 230         struct nlm_rqst *call;
 231
 232         for(;;) {
 233                 call = kzalloc(sizeof(*call), GFP_KERNEL);
 234                 if (call != NULL) {
 235                         locks_init_lock(&call->a_args.lock.fl);
 236                         locks_init_lock(&call->a_res.lock.fl);
 237                         call->a_host = host;
 238                         return call;
 239                 }
 240                 if (signalled())
 241                         break;
 242                 printk("nlm_alloc_call: failed, waiting for memory\n");
 243                 schedule_timeout_interruptible(5*HZ);
 244         }
 245         nlm_release_host(host);
 246         return NULL;
 247 }
 248
 249 void nlm_release_call(struct nlm_rqst *call)
 250 {
 251         nlm_release_host(call->a_host);
 252         nlmclnt_release_lockargs(call);
 253         kfree(call);
 254 }
 255
 256 static void nlmclnt_rpc_release(void *data)
 257 {
 258         return nlm_release_call(data);
 259 }
 260
 261 static int nlm_wait_on_grace(wait_queue_head_t *queue)
 262 {
 263         DEFINE_WAIT(wait);
 264         int status = -EINTR;
 265
 266         prepare_to_wait(queue, &wait, TASK_INTERRUPTIBLE);
 267         if (!signalled ()) {
 268                 schedule_timeout(NLMCLNT_GRACE_WAIT);
 269                 try_to_freeze();
 270                 if (!signalled ())
 271                         status = 0;
 272         }
 273         finish_wait(queue, &wait);
 274         return status;
 275 }
 276
 277 /*
 278  * Generic NLM call
 279  */
 280 static int
 281 nlmclnt_call(struct nlm_rqst *req, u32 proc)
 282 {
 283         struct nlm_host *host = req->a_host;
 284         struct rpc_clnt *clnt;
 285         struct nlm_args *argp = &req->a_args;
 286         struct nlm_res  *resp = &req->a_res;
 287         struct rpc_message msg = {
 288                 .rpc_argp       = argp,
 289                 .rpc_resp       = resp,
 290         };
 291         int             status;
 292
 293         dprintk("lockd: call procedure %d on %s\n",
 294                         (int)proc, host->h_name);
 295
 296         do {
 297                 if (host->h_reclaiming && !argp->reclaim)
 298                         goto in_grace_period;
 299
 300                 /* If we have no RPC client yet, create one. */
 301                 if ((clnt = nlm_bind_host(host)) == NULL)
 302                         return -ENOLCK;
 303                 msg.rpc_proc = &clnt->cl_procinfo[proc];
 304
 305                 /* Perform the RPC call. If an error occurs, try again */
 306                 if ((status = rpc_call_sync(clnt, &msg, 0)) < 0) {
 307                         dprintk("lockd: rpc_call returned error %d\n", -status);
 308                         switch (status) {
 309                         case -EPROTONOSUPPORT:
 310                                 status = -EINVAL;
 311                                 break;
 312                         case -ECONNREFUSED:
 313                         case -ETIMEDOUT:
 314                         case -ENOTCONN:
 315                                 nlm_rebind_host(host);
 316                                 status = -EAGAIN;
 317                                 break;
 318                         case -ERESTARTSYS:
 319                                 return signalled () ? -EINTR : status;
 320                         default:
 321                                 break;
 322                         }
 323                         break;
 324                 } else
 325                 if (resp->status == NLM_LCK_DENIED_GRACE_PERIOD) {
 326                         dprintk("lockd: server in grace period\n");
 327                         if (argp->reclaim) {
 328                                 printk(KERN_WARNING
 329                                      "lockd: spurious grace period reject?!\n");
 330                                 return -ENOLCK;
 331                         }
 332                 } else {
 333                         if (!argp->reclaim) {
 334                                 /* We appear to be out of the grace period */
 335                                 wake_up_all(&host->h_gracewait);
 336                         }
 337                         dprintk("lockd: server returns status %d\n", resp->status);
 338                         return 0;       /* Okay, call complete */
 339                 }
 340
 341 in_grace_period:
 342                 /*
 343                  * The server has rebooted and appears to be in the grace
 344                  * period during which locks are only allowed to be
 345                  * reclaimed.
 346                  * We can only back off and try again later.
 347                  */
 348                 status = nlm_wait_on_grace(&host->h_gracewait);
 349         } while (status == 0);
 350
 351         return status;
 352 }
 353
 354 /*
 355  * Generic NLM call, async version.
 356  */
 357 static int __nlm_async_call(struct nlm_rqst *req, u32 proc, struct rpc_message *msg, const struct rpc_call_ops *tk_ops)
 358 {
 359         struct nlm_host *host = req->a_host;
 360         struct rpc_clnt *clnt;
 361         int status = -ENOLCK;
 362
 363         dprintk("lockd: call procedure %d on %s (async)\n",
 364                         (int)proc, host->h_name);
 365
 366         /* If we have no RPC client yet, create one. */
 367         clnt = nlm_bind_host(host);
 368         if (clnt == NULL)
 369                 goto out_err;
 370         msg->rpc_proc = &clnt->cl_procinfo[proc];
 371
 372         /* bootstrap and kick off the async RPC call */
 373         status = rpc_call_async(clnt, msg, RPC_TASK_ASYNC, tk_ops, req);
 374         if (status == 0)
 375                 return 0;
 376 out_err:
 377         nlm_release_call(req);
 378         return status;
 379 }
 380
 381 int nlm_async_call(struct nlm_rqst *req, u32 proc, const struct rpc_call_ops *tk_ops)
 382 {
 383         struct rpc_message msg = {
 384                 .rpc_argp       = &req->a_args,
 385                 .rpc_resp       = &req->a_res,
 386         };
 387         return __nlm_async_call(req, proc, &msg, tk_ops);
 388 }
 389
 390 int nlm_async_reply(struct nlm_rqst *req, u32 proc, const struct rpc_call_ops *tk_ops)
 391 {
 392         struct rpc_message msg = {
 393                 .rpc_argp       = &req->a_res,
 394         };
 395         return __nlm_async_call(req, proc, &msg, tk_ops);
 396 }
 397
 398 /*
 399  * TEST for the presence of a conflicting lock
 400  */
 401 static int
 402 nlmclnt_test(struct nlm_rqst *req, struct file_lock *fl)
 403 {
 404         int     status;
 405
 406         status = nlmclnt_call(req, NLMPROC_TEST);
 407         if (status < 0)
 408                 goto out;
 409
 410         switch (req->a_res.status) {
 411                 case NLM_LCK_GRANTED:
 412                         fl->fl_type = F_UNLCK;
 413                         break;
 414                 case NLM_LCK_DENIED:
 415                         /*
 416                          * Report the conflicting lock back to the application.
 417                          */
 418                         fl->fl_start = req->a_res.lock.fl.fl_start;
 419                         fl->fl_end = req->a_res.lock.fl.fl_start;
 420                         fl->fl_type = req->a_res.lock.fl.fl_type;
 421                         fl->fl_pid = 0;
 422                         break;
 423                 default:
 424                         status = nlm_stat_to_errno(req->a_res.status);
 425         }
 426 out:
 427         nlm_release_call(req);
 428         return status;
 429 }
 430
 431 static void nlmclnt_locks_copy_lock(struct file_lock *new, struct file_lock *fl)
 432 {
 433         new->fl_u.nfs_fl.state = fl->fl_u.nfs_fl.state;
 434         new->fl_u.nfs_fl.owner = nlm_get_lockowner(fl->fl_u.nfs_fl.owner);
 435         list_add_tail(&new->fl_u.nfs_fl.list, &fl->fl_u.nfs_fl.owner->host->h_granted);
 436 }
 437
 438 static void nlmclnt_locks_release_private(struct file_lock *fl)
 439 {
 440         list_del(&fl->fl_u.nfs_fl.list);
 441         nlm_put_lockowner(fl->fl_u.nfs_fl.owner);
 442 }
 443
 444 static struct file_lock_operations nlmclnt_lock_ops = {
 445         .fl_copy_lock = nlmclnt_locks_copy_lock,
 446         .fl_release_private = nlmclnt_locks_release_private,
 447 };
 448
 449 static void nlmclnt_locks_init_private(struct file_lock *fl, struct nlm_host *host)
 450 {
 451         BUG_ON(fl->fl_ops != NULL);
 452         fl->fl_u.nfs_fl.state = 0;
 453         fl->fl_u.nfs_fl.owner = nlm_find_lockowner(host, fl->fl_owner);
 454         INIT_LIST_HEAD(&fl->fl_u.nfs_fl.list);
 455         fl->fl_ops = &nlmclnt_lock_ops;
 456 }
 457
 458 static void do_vfs_lock(struct file_lock *fl)
 459 {
 460         int res = 0;
 461         switch (fl->fl_flags & (FL_POSIX|FL_FLOCK)) {
 462                 case FL_POSIX:
 463                         res = posix_lock_file_wait(fl->fl_file, fl);
 464                         break;
 465                 case FL_FLOCK:
 466                         res = flock_lock_file_wait(fl->fl_file, fl);
 467                         break;
 468                 default:
 469                         BUG();
 470         }
 471         if (res < 0)
 472                 printk(KERN_WARNING "%s: VFS is out of sync with lock manager!\n",
 473                                 __FUNCTION__);
 474 }
 475
 476 /*
 477  * LOCK: Try to create a lock
 478  *
 479  *                      Programmer Harassment Alert
 480  *
 481  * When given a blocking lock request in a sync RPC call, the HPUX lockd
 482  * will faithfully return LCK_BLOCKED but never cares to notify us when
 483  * the lock could be granted. This way, our local process could hang
 484  * around forever waiting for the callback.
 485  *
 486  *  Solution A: Implement busy-waiting
 487  *  Solution B: Use the async version of the call (NLM_LOCK_{MSG,RES})
 488  *
 489  * For now I am implementing solution A, because I hate the idea of
 490  * re-implementing lockd for a third time in two months. The async
 491  * calls shouldn't be too hard to do, however.
 492  *
 493  * This is one of the lovely things about standards in the NFS area:
 494  * they're so soft and squishy you can't really blame HP for doing this.
 495  */
 496 static int
 497 nlmclnt_lock(struct nlm_rqst *req, struct file_lock *fl)
 498 {
 499         struct nlm_host *host = req->a_host;
 500         struct nlm_res  *resp = &req->a_res;
 501         struct nlm_wait *block = NULL;
 502         int status = -ENOLCK;
 503
 504         if (!host->h_monitored && nsm_monitor(host) < 0) {
 505                 printk(KERN_NOTICE "lockd: failed to monitor %s\n",
 506                                         host->h_name);
 507                 goto out;
 508         }
 509
 510         block = nlmclnt_prepare_block(host, fl);
 511         for(;;) {
 512                 status = nlmclnt_call(req, NLMPROC_LOCK);
 513                 if (status < 0)
 514                         goto out_unblock;
 515                 if (!req->a_args.block)
 516                         break;
 517                 /* Did a reclaimer thread notify us of a server reboot? */
 518                 if (resp->status ==  NLM_LCK_DENIED_GRACE_PERIOD)
 519                         continue;
 520                 if (resp->status != NLM_LCK_BLOCKED)
 521                         break;
 522                 /* Wait on an NLM blocking lock */
 523                 status = nlmclnt_block(block, req, NLMCLNT_POLL_TIMEOUT);
 524                 /* if we were interrupted. Send a CANCEL request to the server
 525                  * and exit
 526                  */
 527                 if (status < 0)
 528                         goto out_unblock;
 529                 if (resp->status != NLM_LCK_BLOCKED)
 530                         break;
 531         }
 532
 533         if (resp->status == NLM_LCK_GRANTED) {
 534                 fl->fl_u.nfs_fl.state = host->h_state;
 535                 fl->fl_flags |= FL_SLEEP;
 536                 /* Ensure the resulting lock will get added to granted list */
 537                 do_vfs_lock(fl);
 538         }
 539         status = nlm_stat_to_errno(resp->status);
 540 out_unblock:
 541         nlmclnt_finish_block(block);
 542         /* Cancel the blocked request if it is still pending */
 543         if (resp->status == NLM_LCK_BLOCKED)
 544                 nlmclnt_cancel(host, req->a_args.block, fl);
 545 out:
 546         nlm_release_call(req);
 547         return status;
 548 }
 549
 550 /*
 551  * RECLAIM: Try to reclaim a lock
 552  */
 553 int
 554 nlmclnt_reclaim(struct nlm_host *host, struct file_lock *fl)
 555 {
 556         struct nlm_rqst reqst, *req;
 557         int             status;
 558
 559         req = &reqst;
 560         memset(req, 0, sizeof(*req));
 561         locks_init_lock(&req->a_args.lock.fl);
 562         locks_init_lock(&req->a_res.lock.fl);
 563         req->a_host  = host;
 564         req->a_flags = 0;
 565
 566         /* Set up the argument struct */
 567         nlmclnt_setlockargs(req, fl);
 568         req->a_args.reclaim = 1;
 569
 570         if ((status = nlmclnt_call(req, NLMPROC_LOCK)) >= 0
 571          && req->a_res.status == NLM_LCK_GRANTED)
 572                 return 0;
 573
 574         printk(KERN_WARNING "lockd: failed to reclaim lock for pid %d "
 575                                 "(errno %d, status %d)\n", fl->fl_pid,
 576                                 status, req->a_res.status);
 577
 578         /*
 579          * FIXME: This is a serious failure. We can
 580          *
 581          *  a.  Ignore the problem
 582          *  b.  Send the owning process some signal (Linux doesn't have
 583          *      SIGLOST, though...)
 584          *  c.  Retry the operation
 585          *
 586          * Until someone comes up with a simple implementation
 587          * for b or c, I'll choose option a.
 588          */
 589
 590         return -ENOLCK;
 591 }
 592
 593 /*
 594  * UNLOCK: remove an existing lock
 595  */
 596 static int
 597 nlmclnt_unlock(struct nlm_rqst *req, struct file_lock *fl)
 598 {
 599         struct nlm_res  *resp = &req->a_res;
 600         int             status;
 601
 602         /*
 603          * Note: the server is supposed to either grant us the unlock
 604          * request, or to deny it with NLM_LCK_DENIED_GRACE_PERIOD. In either
 605          * case, we want to unlock.
 606          */
 607         do_vfs_lock(fl);
 608
 609         if (req->a_flags & RPC_TASK_ASYNC)
 610                 return nlm_async_call(req, NLMPROC_UNLOCK, &nlmclnt_unlock_ops);
 611
 612         status = nlmclnt_call(req, NLMPROC_UNLOCK);
 613         if (status < 0)
 614                 goto out;
 615
 616         status = 0;
 617         if (resp->status == NLM_LCK_GRANTED)
 618                 goto out;
 619
 620         if (resp->status != NLM_LCK_DENIED_NOLOCKS)
 621                 printk("lockd: unexpected unlock status: %d\n", resp->status);
 622         /* What to do now? I'm out of my depth... */
 623         status = -ENOLCK;
 624 out:
 625         nlm_release_call(req);
 626         return status;
 627 }
 628
 629 static void nlmclnt_unlock_callback(struct rpc_task *task, void *data)
 630 {
 631         struct nlm_rqst *req = data;
 632         int             status = req->a_res.status;
 633
 634         if (RPC_ASSASSINATED(task))
 635                 goto die;
 636
 637         if (task->tk_status < 0) {
 638                 dprintk("lockd: unlock failed (err = %d)\n", -task->tk_status);
 639                 goto retry_rebind;
 640         }
 641         if (status == NLM_LCK_DENIED_GRACE_PERIOD) {
 642                 rpc_delay(task, NLMCLNT_GRACE_WAIT);
 643                 goto retry_unlock;
 644         }
 645         if (status != NLM_LCK_GRANTED)
 646                 printk(KERN_WARNING "lockd: unexpected unlock status: %d\n", status);
 647 die:
 648         return;
 649  retry_rebind:
 650         nlm_rebind_host(req->a_host);
 651  retry_unlock:
 652         rpc_restart_call(task);
 653 }
 654
 655 static const struct rpc_call_ops nlmclnt_unlock_ops = {
 656         .rpc_call_done = nlmclnt_unlock_callback,
 657         .rpc_release = nlmclnt_rpc_release,
 658 };
 659
 660 /*
 661  * Cancel a blocked lock request.
 662  * We always use an async RPC call for this in order not to hang a
 663  * process that has been Ctrl-C'ed.
 664  */
 665 static int nlmclnt_cancel(struct nlm_host *host, int block, struct file_lock *fl)
 666 {
 667         struct nlm_rqst *req;
 668         unsigned long   flags;
 669         sigset_t        oldset;
 670         int             status;
 671
 672         /* Block all signals while setting up call */
 673         spin_lock_irqsave(&current->sighand->siglock, flags);
 674         oldset = current->blocked;
 675         sigfillset(&current->blocked);
 676         recalc_sigpending();
 677         spin_unlock_irqrestore(&current->sighand->siglock, flags);
 678
 679         req = nlm_alloc_call(nlm_get_host(host));
 680         if (!req)
 681                 return -ENOMEM;
 682         req->a_flags = RPC_TASK_ASYNC;
 683
 684         nlmclnt_setlockargs(req, fl);
 685         req->a_args.block = block;
 686
 687         status = nlm_async_call(req, NLMPROC_CANCEL, &nlmclnt_cancel_ops);
 688
 689         spin_lock_irqsave(&current->sighand->siglock, flags);
 690         current->blocked = oldset;
 691         recalc_sigpending();
 692         spin_unlock_irqrestore(&current->sighand->siglock, flags);
 693
 694         return status;
 695 }
 696
 697 static void nlmclnt_cancel_callback(struct rpc_task *task, void *data)
 698 {
 699         struct nlm_rqst *req = data;
 700
 701         if (RPC_ASSASSINATED(task))
 702                 goto die;
 703
 704         if (task->tk_status < 0) {
 705                 dprintk("lockd: CANCEL call error %d, retrying.\n",
 706                                         task->tk_status);
 707                 goto retry_cancel;
 708         }
 709
 710         dprintk("lockd: cancel status %d (task %d)\n",
 711                         req->a_res.status, task->tk_pid);
 712
 713         switch (req->a_res.status) {
 714         case NLM_LCK_GRANTED:
 715         case NLM_LCK_DENIED_GRACE_PERIOD:
 716         case NLM_LCK_DENIED:
 717                 /* Everything's good */
 718                 break;
 719         case NLM_LCK_DENIED_NOLOCKS:
 720                 dprintk("lockd: CANCEL failed (server has no locks)\n");
 721                 goto retry_cancel;
 722         default:
 723                 printk(KERN_NOTICE "lockd: weird return %d for CANCEL call\n",
 724                         req->a_res.status);
 725         }
 726
 727 die:
 728         return;
 729
 730 retry_cancel:
 731         /* Don't ever retry more than 3 times */
 732         if (req->a_retries++ >= NLMCLNT_MAX_RETRIES)
 733                 goto die;
 734         nlm_rebind_host(req->a_host);
 735         rpc_restart_call(task);
 736         rpc_delay(task, 30 * HZ);
 737 }
 738
 739 static const struct rpc_call_ops nlmclnt_cancel_ops = {
 740         .rpc_call_done = nlmclnt_cancel_callback,
 741         .rpc_release = nlmclnt_rpc_release,
 742 };
 743
 744 /*
 745  * Convert an NLM status code to a generic kernel errno
 746  */
 747 static int
 748 nlm_stat_to_errno(u32 status)
 749 {
 750         switch(status) {
 751         case NLM_LCK_GRANTED:
 752                 return 0;
 753         case NLM_LCK_DENIED:
 754                 return -EAGAIN;
 755         case NLM_LCK_DENIED_NOLOCKS:
 756         case NLM_LCK_DENIED_GRACE_PERIOD:
 757                 return -ENOLCK;
 758         case NLM_LCK_BLOCKED:
 759                 printk(KERN_NOTICE "lockd: unexpected status NLM_BLOCKED\n");
 760                 return -ENOLCK;
 761 #ifdef CONFIG_LOCKD_V4
 762         case NLM_DEADLCK:
 763                 return -EDEADLK;
 764         case NLM_ROFS:
 765                 return -EROFS;
 766         case NLM_STALE_FH:
 767                 return -ESTALE;
 768         case NLM_FBIG:
 769                 return -EOVERFLOW;
 770         case NLM_FAILED:
 771                 return -ENOLCK;
 772 #endif
 773         }
 774         printk(KERN_NOTICE "lockd: unexpected server status %d\n", status);
 775         return -ENOLCK;
 776 }