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/module.h>
  10 #include <linux/types.h>
  11 #include <linux/errno.h>
  12 #include <linux/fs.h>
  13 #include <linux/nfs_fs.h>
  14 #include <linux/utsname.h>
  15 #include <linux/freezer.h>
  16 #include <linux/sunrpc/clnt.h>
  17 #include <linux/sunrpc/svc.h>
  18 #include <linux/lockd/lockd.h>
  19 #include <linux/lockd/sm_inter.h>
  20
  21 #define NLMDBG_FACILITY         NLMDBG_CLIENT
  22 #define NLMCLNT_GRACE_WAIT      (5*HZ)
  23 #define NLMCLNT_POLL_TIMEOUT    (30*HZ)
  24 #define NLMCLNT_MAX_RETRIES     3
  25
  26 static int      nlmclnt_test(struct nlm_rqst *, struct file_lock *);
  27 static int      nlmclnt_lock(struct nlm_rqst *, struct file_lock *);
  28 static int      nlmclnt_unlock(struct nlm_rqst *, struct file_lock *);
  29 static int      nlm_stat_to_errno(__be32 stat);
  30 static void     nlmclnt_locks_init_private(struct file_lock *fl, struct nlm_host *host);
  31 static int      nlmclnt_cancel(struct nlm_host *, int , struct file_lock *);
  32
  33 static const struct rpc_call_ops nlmclnt_unlock_ops;
  34 static const struct rpc_call_ops nlmclnt_cancel_ops;
  35
  36 /*
  37  * Cookie counter for NLM requests
  38  */
  39 static atomic_t nlm_cookie = ATOMIC_INIT(0x1234);
  40
  41 void nlmclnt_next_cookie(struct nlm_cookie *c)
  42 {
  43         u32     cookie = atomic_inc_return(&nlm_cookie);
  44
  45         memcpy(c->data, &cookie, 4);
  46         c->len=4;
  47 }
  48
  49 static struct nlm_lockowner *nlm_get_lockowner(struct nlm_lockowner *lockowner)
  50 {
  51         atomic_inc(&lockowner->count);
  52         return lockowner;
  53 }
  54
  55 static void nlm_put_lockowner(struct nlm_lockowner *lockowner)
  56 {
  57         if (!atomic_dec_and_lock(&lockowner->count, &lockowner->host->h_lock))
  58                 return;
  59         list_del(&lockowner->list);
  60         spin_unlock(&lockowner->host->h_lock);
  61         nlm_release_host(lockowner->host);
  62         kfree(lockowner);
  63 }
  64
  65 static inline int nlm_pidbusy(struct nlm_host *host, uint32_t pid)
  66 {
  67         struct nlm_lockowner *lockowner;
  68         list_for_each_entry(lockowner, &host->h_lockowners, list) {
  69                 if (lockowner->pid == pid)
  70                         return -EBUSY;
  71         }
  72         return 0;
  73 }
  74
  75 static inline uint32_t __nlm_alloc_pid(struct nlm_host *host)
  76 {
  77         uint32_t res;
  78         do {
  79                 res = host->h_pidcount++;
  80         } while (nlm_pidbusy(host, res) < 0);
  81         return res;
  82 }
  83
  84 static struct nlm_lockowner *__nlm_find_lockowner(struct nlm_host *host, fl_owner_t owner)
  85 {
  86         struct nlm_lockowner *lockowner;
  87         list_for_each_entry(lockowner, &host->h_lockowners, list) {
  88                 if (lockowner->owner != owner)
  89                         continue;
  90                 return nlm_get_lockowner(lockowner);
  91         }
  92         return NULL;
  93 }
  94
  95 static struct nlm_lockowner *nlm_find_lockowner(struct nlm_host *host, fl_owner_t owner)
  96 {
  97         struct nlm_lockowner *res, *new = NULL;
  98
  99         spin_lock(&host->h_lock);
 100         res = __nlm_find_lockowner(host, owner);
 101         if (res == NULL) {
 102                 spin_unlock(&host->h_lock);
 103                 new = kmalloc(sizeof(*new), GFP_KERNEL);
 104                 spin_lock(&host->h_lock);
 105                 res = __nlm_find_lockowner(host, owner);
 106                 if (res == NULL && new != NULL) {
 107                         res = new;
 108                         atomic_set(&new->count, 1);
 109                         new->owner = owner;
 110                         new->pid = __nlm_alloc_pid(host);
 111                         new->host = nlm_get_host(host);
 112                         list_add(&new->list, &host->h_lockowners);
 113                         new = NULL;
 114                 }
 115         }
 116         spin_unlock(&host->h_lock);
 117         kfree(new);
 118         return res;
 119 }
 120
 121 /*
 122  * Initialize arguments for TEST/LOCK/UNLOCK/CANCEL calls
 123  */
 124 static void nlmclnt_setlockargs(struct nlm_rqst *req, struct file_lock *fl)
 125 {
 126         struct nlm_args *argp = &req->a_args;
 127         struct nlm_lock *lock = &argp->lock;
 128
 129         nlmclnt_next_cookie(&argp->cookie);
 130         argp->state   = nsm_local_state;
 131         memcpy(&lock->fh, NFS_FH(fl->fl_file->f_path.dentry->d_inode), sizeof(struct nfs_fh));
 132         lock->caller  = utsname()->nodename;
 133         lock->oh.data = req->a_owner;
 134         lock->oh.len  = snprintf(req->a_owner, sizeof(req->a_owner), "%u@%s",
 135                                 (unsigned int)fl->fl_u.nfs_fl.owner->pid,
 136                                 utsname()->nodename);
 137         lock->svid = fl->fl_u.nfs_fl.owner->pid;
 138         lock->fl.fl_start = fl->fl_start;
 139         lock->fl.fl_end = fl->fl_end;
 140         lock->fl.fl_type = fl->fl_type;
 141 }
 142
 143 static void nlmclnt_release_lockargs(struct nlm_rqst *req)
 144 {
 145         BUG_ON(req->a_args.lock.fl.fl_ops != NULL);
 146 }
 147
 148 /**
 149  * nlmclnt_proc - Perform a single client-side lock request
 150  * @host: address of a valid nlm_host context representing the NLM server
 151  * @cmd: fcntl-style file lock operation to perform
 152  * @fl: address of arguments for the lock operation
 153  *
 154  */
 155 int nlmclnt_proc(struct nlm_host *host, int cmd, struct file_lock *fl)
 156 {
 157         struct nlm_rqst         *call;
 158         sigset_t                oldset;
 159         unsigned long           flags;
 160         int                     status;
 161
 162         nlm_get_host(host);
 163         call = nlm_alloc_call(host);
 164         if (call == NULL)
 165                 return -ENOMEM;
 166
 167         nlmclnt_locks_init_private(fl, host);
 168         /* Set up the argument struct */
 169         nlmclnt_setlockargs(call, fl);
 170
 171         /* Keep the old signal mask */
 172         spin_lock_irqsave(&current->sighand->siglock, flags);
 173         oldset = current->blocked;
 174
 175         /* If we're cleaning up locks because the process is exiting,
 176          * perform the RPC call asynchronously. */
 177         if ((IS_SETLK(cmd) || IS_SETLKW(cmd))
 178             && fl->fl_type == F_UNLCK
 179             && (current->flags & PF_EXITING)) {
 180                 sigfillset(&current->blocked);  /* Mask all signals */
 181                 recalc_sigpending();
 182
 183                 call->a_flags = RPC_TASK_ASYNC;
 184         }
 185         spin_unlock_irqrestore(&current->sighand->siglock, flags);
 186
 187         if (IS_SETLK(cmd) || IS_SETLKW(cmd)) {
 188                 if (fl->fl_type != F_UNLCK) {
 189                         call->a_args.block = IS_SETLKW(cmd) ? 1 : 0;
 190                         status = nlmclnt_lock(call, fl);
 191                 } else
 192                         status = nlmclnt_unlock(call, fl);
 193         } else if (IS_GETLK(cmd))
 194                 status = nlmclnt_test(call, fl);
 195         else
 196                 status = -EINVAL;
 197
 198         fl->fl_ops->fl_release_private(fl);
 199         fl->fl_ops = NULL;
 200
 201         spin_lock_irqsave(&current->sighand->siglock, flags);
 202         current->blocked = oldset;
 203         recalc_sigpending();
 204         spin_unlock_irqrestore(&current->sighand->siglock, flags);
 205
 206         dprintk("lockd: clnt proc returns %d\n", status);
 207         return status;
 208 }
 209 EXPORT_SYMBOL_GPL(nlmclnt_proc);
 210
 211 /*
 212  * Allocate an NLM RPC call struct
 213  *
 214  * Note: the caller must hold a reference to host. In case of failure,
 215  * this reference will be released.
 216  */
 217 struct nlm_rqst *nlm_alloc_call(struct nlm_host *host)
 218 {
 219         struct nlm_rqst *call;
 220
 221         for(;;) {
 222                 call = kzalloc(sizeof(*call), GFP_KERNEL);
 223                 if (call != NULL) {
 224                         locks_init_lock(&call->a_args.lock.fl);
 225                         locks_init_lock(&call->a_res.lock.fl);
 226                         call->a_host = host;
 227                         return call;
 228                 }
 229                 if (signalled())
 230                         break;
 231                 printk("nlm_alloc_call: failed, waiting for memory\n");
 232                 schedule_timeout_interruptible(5*HZ);
 233         }
 234         nlm_release_host(host);
 235         return NULL;
 236 }
 237
 238 void nlm_release_call(struct nlm_rqst *call)
 239 {
 240         nlm_release_host(call->a_host);
 241         nlmclnt_release_lockargs(call);
 242         kfree(call);
 243 }
 244
 245 static void nlmclnt_rpc_release(void *data)
 246 {
 247         nlm_release_call(data);
 248 }
 249
 250 static int nlm_wait_on_grace(wait_queue_head_t *queue)
 251 {
 252         DEFINE_WAIT(wait);
 253         int status = -EINTR;
 254
 255         prepare_to_wait(queue, &wait, TASK_INTERRUPTIBLE);
 256         if (!signalled ()) {
 257                 schedule_timeout(NLMCLNT_GRACE_WAIT);
 258                 try_to_freeze();
 259                 if (!signalled ())
 260                         status = 0;
 261         }
 262         finish_wait(queue, &wait);
 263         return status;
 264 }
 265
 266 /*
 267  * Generic NLM call
 268  */
 269 static int
 270 nlmclnt_call(struct nlm_rqst *req, u32 proc)
 271 {
 272         struct nlm_host *host = req->a_host;
 273         struct rpc_clnt *clnt;
 274         struct nlm_args *argp = &req->a_args;
 275         struct nlm_res  *resp = &req->a_res;
 276         struct rpc_message msg = {
 277                 .rpc_argp       = argp,
 278                 .rpc_resp       = resp,
 279         };
 280         int             status;
 281
 282         dprintk("lockd: call procedure %d on %s\n",
 283                         (int)proc, host->h_name);
 284
 285         do {
 286                 if (host->h_reclaiming && !argp->reclaim)
 287                         goto in_grace_period;
 288
 289                 /* If we have no RPC client yet, create one. */
 290                 if ((clnt = nlm_bind_host(host)) == NULL)
 291                         return -ENOLCK;
 292                 msg.rpc_proc = &clnt->cl_procinfo[proc];
 293
 294                 /* Perform the RPC call. If an error occurs, try again */
 295                 if ((status = rpc_call_sync(clnt, &msg, 0)) < 0) {
 296                         dprintk("lockd: rpc_call returned error %d\n", -status);
 297                         switch (status) {
 298                         case -EPROTONOSUPPORT:
 299                                 status = -EINVAL;
 300                                 break;
 301                         case -ECONNREFUSED:
 302                         case -ETIMEDOUT:
 303                         case -ENOTCONN:
 304                                 nlm_rebind_host(host);
 305                                 status = -EAGAIN;
 306                                 break;
 307                         case -ERESTARTSYS:
 308                                 return signalled () ? -EINTR : status;
 309                         default:
 310                                 break;
 311                         }
 312                         break;
 313                 } else
 314                 if (resp->status == nlm_lck_denied_grace_period) {
 315                         dprintk("lockd: server in grace period\n");
 316                         if (argp->reclaim) {
 317                                 printk(KERN_WARNING
 318                                      "lockd: spurious grace period reject?!\n");
 319                                 return -ENOLCK;
 320                         }
 321                 } else {
 322                         if (!argp->reclaim) {
 323                                 /* We appear to be out of the grace period */
 324                                 wake_up_all(&host->h_gracewait);
 325                         }
 326                         dprintk("lockd: server returns status %d\n", resp->status);
 327                         return 0;       /* Okay, call complete */
 328                 }
 329
 330 in_grace_period:
 331                 /*
 332                  * The server has rebooted and appears to be in the grace
 333                  * period during which locks are only allowed to be
 334                  * reclaimed.
 335                  * We can only back off and try again later.
 336                  */
 337                 status = nlm_wait_on_grace(&host->h_gracewait);
 338         } while (status == 0);
 339
 340         return status;
 341 }
 342
 343 /*
 344  * Generic NLM call, async version.
 345  */
 346 static int __nlm_async_call(struct nlm_rqst *req, u32 proc, struct rpc_message *msg, const struct rpc_call_ops *tk_ops)
 347 {
 348         struct nlm_host *host = req->a_host;
 349         struct rpc_clnt *clnt;
 350
 351         dprintk("lockd: call procedure %d on %s (async)\n",
 352                         (int)proc, host->h_name);
 353
 354         /* If we have no RPC client yet, create one. */
 355         clnt = nlm_bind_host(host);
 356         if (clnt == NULL)
 357                 goto out_err;
 358         msg->rpc_proc = &clnt->cl_procinfo[proc];
 359
 360         /* bootstrap and kick off the async RPC call */
 361         return rpc_call_async(clnt, msg, RPC_TASK_ASYNC, tk_ops, req);
 362 out_err:
 363         tk_ops->rpc_release(req);
 364         return -ENOLCK;
 365 }
 366
 367 int nlm_async_call(struct nlm_rqst *req, u32 proc, const struct rpc_call_ops *tk_ops)
 368 {
 369         struct rpc_message msg = {
 370                 .rpc_argp       = &req->a_args,
 371                 .rpc_resp       = &req->a_res,
 372         };
 373         return __nlm_async_call(req, proc, &msg, tk_ops);
 374 }
 375
 376 int nlm_async_reply(struct nlm_rqst *req, u32 proc, const struct rpc_call_ops *tk_ops)
 377 {
 378         struct rpc_message msg = {
 379                 .rpc_argp       = &req->a_res,
 380         };
 381         return __nlm_async_call(req, proc, &msg, tk_ops);
 382 }
 383
 384 /*
 385  * TEST for the presence of a conflicting lock
 386  */
 387 static int
 388 nlmclnt_test(struct nlm_rqst *req, struct file_lock *fl)
 389 {
 390         int     status;
 391
 392         status = nlmclnt_call(req, NLMPROC_TEST);
 393         if (status < 0)
 394                 goto out;
 395
 396         switch (req->a_res.status) {
 397                 case nlm_granted:
 398                         fl->fl_type = F_UNLCK;
 399                         break;
 400                 case nlm_lck_denied:
 401                         /*
 402                          * Report the conflicting lock back to the application.
 403                          */
 404                         fl->fl_start = req->a_res.lock.fl.fl_start;
 405                         fl->fl_end = req->a_res.lock.fl.fl_start;
 406                         fl->fl_type = req->a_res.lock.fl.fl_type;
 407                         fl->fl_pid = 0;
 408                         break;
 409                 default:
 410                         status = nlm_stat_to_errno(req->a_res.status);
 411         }
 412 out:
 413         nlm_release_call(req);
 414         return status;
 415 }
 416
 417 static void nlmclnt_locks_copy_lock(struct file_lock *new, struct file_lock *fl)
 418 {
 419         new->fl_u.nfs_fl.state = fl->fl_u.nfs_fl.state;
 420         new->fl_u.nfs_fl.owner = nlm_get_lockowner(fl->fl_u.nfs_fl.owner);
 421         list_add_tail(&new->fl_u.nfs_fl.list, &fl->fl_u.nfs_fl.owner->host->h_granted);
 422 }
 423
 424 static void nlmclnt_locks_release_private(struct file_lock *fl)
 425 {
 426         list_del(&fl->fl_u.nfs_fl.list);
 427         nlm_put_lockowner(fl->fl_u.nfs_fl.owner);
 428 }
 429
 430 static struct file_lock_operations nlmclnt_lock_ops = {
 431         .fl_copy_lock = nlmclnt_locks_copy_lock,
 432         .fl_release_private = nlmclnt_locks_release_private,
 433 };
 434
 435 static void nlmclnt_locks_init_private(struct file_lock *fl, struct nlm_host *host)
 436 {
 437         BUG_ON(fl->fl_ops != NULL);
 438         fl->fl_u.nfs_fl.state = 0;
 439         fl->fl_u.nfs_fl.owner = nlm_find_lockowner(host, fl->fl_owner);
 440         INIT_LIST_HEAD(&fl->fl_u.nfs_fl.list);
 441         fl->fl_ops = &nlmclnt_lock_ops;
 442 }
 443
 444 static int do_vfs_lock(struct file_lock *fl)
 445 {
 446         int res = 0;
 447         switch (fl->fl_flags & (FL_POSIX|FL_FLOCK)) {
 448                 case FL_POSIX:
 449                         res = posix_lock_file_wait(fl->fl_file, fl);
 450                         break;
 451                 case FL_FLOCK:
 452                         res = flock_lock_file_wait(fl->fl_file, fl);
 453                         break;
 454                 default:
 455                         BUG();
 456         }
 457         return res;
 458 }
 459
 460 /*
 461  * LOCK: Try to create a lock
 462  *
 463  *                      Programmer Harassment Alert
 464  *
 465  * When given a blocking lock request in a sync RPC call, the HPUX lockd
 466  * will faithfully return LCK_BLOCKED but never cares to notify us when
 467  * the lock could be granted. This way, our local process could hang
 468  * around forever waiting for the callback.
 469  *
 470  *  Solution A: Implement busy-waiting
 471  *  Solution B: Use the async version of the call (NLM_LOCK_{MSG,RES})
 472  *
 473  * For now I am implementing solution A, because I hate the idea of
 474  * re-implementing lockd for a third time in two months. The async
 475  * calls shouldn't be too hard to do, however.
 476  *
 477  * This is one of the lovely things about standards in the NFS area:
 478  * they're so soft and squishy you can't really blame HP for doing this.
 479  */
 480 static int
 481 nlmclnt_lock(struct nlm_rqst *req, struct file_lock *fl)
 482 {
 483         struct nlm_host *host = req->a_host;
 484         struct nlm_res  *resp = &req->a_res;
 485         struct nlm_wait *block = NULL;
 486         unsigned char fl_flags = fl->fl_flags;
 487         int status = -ENOLCK;
 488
 489         if (nsm_monitor(host) < 0) {
 490                 printk(KERN_NOTICE "lockd: failed to monitor %s\n",
 491                                         host->h_name);
 492                 goto out;
 493         }
 494         fl->fl_flags |= FL_ACCESS;
 495         status = do_vfs_lock(fl);
 496         if (status < 0)
 497                 goto out;
 498
 499         block = nlmclnt_prepare_block(host, fl);
 500 again:
 501         for(;;) {
 502                 /* Reboot protection */
 503                 fl->fl_u.nfs_fl.state = host->h_state;
 504                 status = nlmclnt_call(req, NLMPROC_LOCK);
 505                 if (status < 0)
 506                         goto out_unblock;
 507                 if (!req->a_args.block)
 508                         break;
 509                 /* Did a reclaimer thread notify us of a server reboot? */
 510                 if (resp->status ==  nlm_lck_denied_grace_period)
 511                         continue;
 512                 if (resp->status != nlm_lck_blocked)
 513                         break;
 514                 /* Wait on an NLM blocking lock */
 515                 status = nlmclnt_block(block, req, NLMCLNT_POLL_TIMEOUT);
 516                 /* if we were interrupted. Send a CANCEL request to the server
 517                  * and exit
 518                  */
 519                 if (status < 0)
 520                         goto out_unblock;
 521                 if (resp->status != nlm_lck_blocked)
 522                         break;
 523         }
 524
 525         if (resp->status == nlm_granted) {
 526                 down_read(&host->h_rwsem);
 527                 /* Check whether or not the server has rebooted */
 528                 if (fl->fl_u.nfs_fl.state != host->h_state) {
 529                         up_read(&host->h_rwsem);
 530                         goto again;
 531                 }
 532                 /* Ensure the resulting lock will get added to granted list */
 533                 fl->fl_flags = fl_flags | FL_SLEEP;
 534                 if (do_vfs_lock(fl) < 0)
 535                         printk(KERN_WARNING "%s: VFS is out of sync with lock manager!\n", __FUNCTION__);
 536                 up_read(&host->h_rwsem);
 537         }
 538         status = nlm_stat_to_errno(resp->status);
 539 out_unblock:
 540         nlmclnt_finish_block(block);
 541         /* Cancel the blocked request if it is still pending */
 542         if (resp->status == nlm_lck_blocked)
 543                 nlmclnt_cancel(host, req->a_args.block, fl);
 544 out:
 545         nlm_release_call(req);
 546         fl->fl_flags = fl_flags;
 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_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, ntohl(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_host *host = req->a_host;
 600         struct nlm_res  *resp = &req->a_res;
 601         int status = 0;
 602
 603         /*
 604          * Note: the server is supposed to either grant us the unlock
 605          * request, or to deny it with NLM_LCK_DENIED_GRACE_PERIOD. In either
 606          * case, we want to unlock.
 607          */
 608         fl->fl_flags |= FL_EXISTS;
 609         down_read(&host->h_rwsem);
 610         if (do_vfs_lock(fl) == -ENOENT) {
 611                 up_read(&host->h_rwsem);
 612                 goto out;
 613         }
 614         up_read(&host->h_rwsem);
 615
 616         if (req->a_flags & RPC_TASK_ASYNC)
 617                 return nlm_async_call(req, NLMPROC_UNLOCK, &nlmclnt_unlock_ops);
 618
 619         status = nlmclnt_call(req, NLMPROC_UNLOCK);
 620         if (status < 0)
 621                 goto out;
 622
 623         if (resp->status == nlm_granted)
 624                 goto out;
 625
 626         if (resp->status != nlm_lck_denied_nolocks)
 627                 printk("lockd: unexpected unlock status: %d\n", resp->status);
 628         /* What to do now? I'm out of my depth... */
 629         status = -ENOLCK;
 630 out:
 631         nlm_release_call(req);
 632         return status;
 633 }
 634
 635 static void nlmclnt_unlock_callback(struct rpc_task *task, void *data)
 636 {
 637         struct nlm_rqst *req = data;
 638         u32 status = ntohl(req->a_res.status);
 639
 640         if (RPC_ASSASSINATED(task))
 641                 goto die;
 642
 643         if (task->tk_status < 0) {
 644                 dprintk("lockd: unlock failed (err = %d)\n", -task->tk_status);
 645                 goto retry_rebind;
 646         }
 647         if (status == NLM_LCK_DENIED_GRACE_PERIOD) {
 648                 rpc_delay(task, NLMCLNT_GRACE_WAIT);
 649                 goto retry_unlock;
 650         }
 651         if (status != NLM_LCK_GRANTED)
 652                 printk(KERN_WARNING "lockd: unexpected unlock status: %d\n", status);
 653 die:
 654         return;
 655  retry_rebind:
 656         nlm_rebind_host(req->a_host);
 657  retry_unlock:
 658         rpc_restart_call(task);
 659 }
 660
 661 static const struct rpc_call_ops nlmclnt_unlock_ops = {
 662         .rpc_call_done = nlmclnt_unlock_callback,
 663         .rpc_release = nlmclnt_rpc_release,
 664 };
 665
 666 /*
 667  * Cancel a blocked lock request.
 668  * We always use an async RPC call for this in order not to hang a
 669  * process that has been Ctrl-C'ed.
 670  */
 671 static int nlmclnt_cancel(struct nlm_host *host, int block, struct file_lock *fl)
 672 {
 673         struct nlm_rqst *req;
 674         unsigned long   flags;
 675         sigset_t        oldset;
 676         int             status;
 677
 678         /* Block all signals while setting up call */
 679         spin_lock_irqsave(&current->sighand->siglock, flags);
 680         oldset = current->blocked;
 681         sigfillset(&current->blocked);
 682         recalc_sigpending();
 683         spin_unlock_irqrestore(&current->sighand->siglock, flags);
 684
 685         req = nlm_alloc_call(nlm_get_host(host));
 686         if (!req)
 687                 return -ENOMEM;
 688         req->a_flags = RPC_TASK_ASYNC;
 689
 690         nlmclnt_setlockargs(req, fl);
 691         req->a_args.block = block;
 692
 693         status = nlm_async_call(req, NLMPROC_CANCEL, &nlmclnt_cancel_ops);
 694
 695         spin_lock_irqsave(&current->sighand->siglock, flags);
 696         current->blocked = oldset;
 697         recalc_sigpending();
 698         spin_unlock_irqrestore(&current->sighand->siglock, flags);
 699
 700         return status;
 701 }
 702
 703 static void nlmclnt_cancel_callback(struct rpc_task *task, void *data)
 704 {
 705         struct nlm_rqst *req = data;
 706         u32 status = ntohl(req->a_res.status);
 707
 708         if (RPC_ASSASSINATED(task))
 709                 goto die;
 710
 711         if (task->tk_status < 0) {
 712                 dprintk("lockd: CANCEL call error %d, retrying.\n",
 713                                         task->tk_status);
 714                 goto retry_cancel;
 715         }
 716
 717         dprintk("lockd: cancel status %u (task %u)\n",
 718                         status, task->tk_pid);
 719
 720         switch (status) {
 721         case NLM_LCK_GRANTED:
 722         case NLM_LCK_DENIED_GRACE_PERIOD:
 723         case NLM_LCK_DENIED:
 724                 /* Everything's good */
 725                 break;
 726         case NLM_LCK_DENIED_NOLOCKS:
 727                 dprintk("lockd: CANCEL failed (server has no locks)\n");
 728                 goto retry_cancel;
 729         default:
 730                 printk(KERN_NOTICE "lockd: weird return %d for CANCEL call\n",
 731                         status);
 732         }
 733
 734 die:
 735         return;
 736
 737 retry_cancel:
 738         /* Don't ever retry more than 3 times */
 739         if (req->a_retries++ >= NLMCLNT_MAX_RETRIES)
 740                 goto die;
 741         nlm_rebind_host(req->a_host);
 742         rpc_restart_call(task);
 743         rpc_delay(task, 30 * HZ);
 744 }
 745
 746 static const struct rpc_call_ops nlmclnt_cancel_ops = {
 747         .rpc_call_done = nlmclnt_cancel_callback,
 748         .rpc_release = nlmclnt_rpc_release,
 749 };
 750
 751 /*
 752  * Convert an NLM status code to a generic kernel errno
 753  */
 754 static int
 755 nlm_stat_to_errno(__be32 status)
 756 {
 757         switch(ntohl(status)) {
 758         case NLM_LCK_GRANTED:
 759                 return 0;
 760         case NLM_LCK_DENIED:
 761                 return -EAGAIN;
 762         case NLM_LCK_DENIED_NOLOCKS:
 763         case NLM_LCK_DENIED_GRACE_PERIOD:
 764                 return -ENOLCK;
 765         case NLM_LCK_BLOCKED:
 766                 printk(KERN_NOTICE "lockd: unexpected status NLM_BLOCKED\n");
 767                 return -ENOLCK;
 768 #ifdef CONFIG_LOCKD_V4
 769         case NLM_DEADLCK:
 770                 return -EDEADLK;
 771         case NLM_ROFS:
 772                 return -EROFS;
 773         case NLM_STALE_FH:
 774                 return -ESTALE;
 775         case NLM_FBIG:
 776                 return -EOVERFLOW;
 777         case NLM_FAILED:
 778                 return -ENOLCK;
 779 #endif
 780         }
 781         printk(KERN_NOTICE "lockd: unexpected server status %d\n", status);
 782         return -ENOLCK;
 783 }