git.oblomov.eu Git - linux-2.6/blob - 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  * This is the main entry point for the NLM client.
 150  */
 151 int
 152 nlmclnt_proc(struct inode *inode, int cmd, struct file_lock *fl)
 153 {
 154         struct rpc_clnt         *client = NFS_CLIENT(inode);
 155         struct sockaddr_in      addr;
 156         struct nfs_server       *nfssrv = NFS_SERVER(inode);
 157         struct nlm_host         *host;
 158         struct nlm_rqst         *call;
 159         sigset_t                oldset;
 160         unsigned long           flags;
 161         int                     status, vers;
 162
 163         vers = (NFS_PROTO(inode)->version == 3) ? 4 : 1;
 164         if (NFS_PROTO(inode)->version > 3) {
 165                 printk(KERN_NOTICE "NFSv4 file locking not implemented!\n");
 166                 return -ENOLCK;
 167         }
 168
 169         rpc_peeraddr(client, (struct sockaddr *) &addr, sizeof(addr));
 170         host = nlmclnt_lookup_host(&addr, client->cl_xprt->prot, vers,
 171                                    nfssrv->nfs_client->cl_hostname,
 172                                    strlen(nfssrv->nfs_client->cl_hostname));
 173         if (host == NULL)
 174                 return -ENOLCK;
 175
 176         call = nlm_alloc_call(host);
 177         if (call == NULL)
 178                 return -ENOMEM;
 179
 180         nlmclnt_locks_init_private(fl, host);
 181         /* Set up the argument struct */
 182         nlmclnt_setlockargs(call, fl);
 183
 184         /* Keep the old signal mask */
 185         spin_lock_irqsave(&current->sighand->siglock, flags);
 186         oldset = current->blocked;
 187
 188         /* If we're cleaning up locks because the process is exiting,
 189          * perform the RPC call asynchronously. */
 190         if ((IS_SETLK(cmd) || IS_SETLKW(cmd))
 191             && fl->fl_type == F_UNLCK
 192             && (current->flags & PF_EXITING)) {
 193                 sigfillset(&current->blocked);  /* Mask all signals */
 194                 recalc_sigpending();
 195
 196                 call->a_flags = RPC_TASK_ASYNC;
 197         }
 198         spin_unlock_irqrestore(&current->sighand->siglock, flags);
 199
 200         if (IS_SETLK(cmd) || IS_SETLKW(cmd)) {
 201                 if (fl->fl_type != F_UNLCK) {
 202                         call->a_args.block = IS_SETLKW(cmd) ? 1 : 0;
 203                         status = nlmclnt_lock(call, fl);
 204                 } else
 205                         status = nlmclnt_unlock(call, fl);
 206         } else if (IS_GETLK(cmd))
 207                 status = nlmclnt_test(call, fl);
 208         else
 209                 status = -EINVAL;
 210
 211         fl->fl_ops->fl_release_private(fl);
 212         fl->fl_ops = NULL;
 213
 214         spin_lock_irqsave(&current->sighand->siglock, flags);
 215         current->blocked = oldset;
 216         recalc_sigpending();
 217         spin_unlock_irqrestore(&current->sighand->siglock, flags);
 218
 219         dprintk("lockd: clnt proc returns %d\n", status);
 220         return status;
 221 }
 222 EXPORT_SYMBOL(nlmclnt_proc);
 223
 224 /*
 225  * Allocate an NLM RPC call struct
 226  *
 227  * Note: the caller must hold a reference to host. In case of failure,
 228  * this reference will be released.
 229  */
 230 struct nlm_rqst *nlm_alloc_call(struct nlm_host *host)
 231 {
 232         struct nlm_rqst *call;
 233
 234         for(;;) {
 235                 call = kzalloc(sizeof(*call), GFP_KERNEL);
 236                 if (call != NULL) {
 237                         locks_init_lock(&call->a_args.lock.fl);
 238                         locks_init_lock(&call->a_res.lock.fl);
 239                         call->a_host = host;
 240                         return call;
 241                 }
 242                 if (signalled())
 243                         break;
 244                 printk("nlm_alloc_call: failed, waiting for memory\n");
 245                 schedule_timeout_interruptible(5*HZ);
 246         }
 247         nlm_release_host(host);
 248         return NULL;
 249 }
 250
 251 void nlm_release_call(struct nlm_rqst *call)
 252 {
 253         nlm_release_host(call->a_host);
 254         nlmclnt_release_lockargs(call);
 255         kfree(call);
 256 }
 257
 258 static void nlmclnt_rpc_release(void *data)
 259 {
 260         return nlm_release_call(data);
 261 }
 262
 263 static int nlm_wait_on_grace(wait_queue_head_t *queue)
 264 {
 265         DEFINE_WAIT(wait);
 266         int status = -EINTR;
 267
 268         prepare_to_wait(queue, &wait, TASK_INTERRUPTIBLE);
 269         if (!signalled ()) {
 270                 schedule_timeout(NLMCLNT_GRACE_WAIT);
 271                 try_to_freeze();
 272                 if (!signalled ())
 273                         status = 0;
 274         }
 275         finish_wait(queue, &wait);
 276         return status;
 277 }
 278
 279 /*
 280  * Generic NLM call
 281  */
 282 static int
 283 nlmclnt_call(struct nlm_rqst *req, u32 proc)
 284 {
 285         struct nlm_host *host = req->a_host;
 286         struct rpc_clnt *clnt;
 287         struct nlm_args *argp = &req->a_args;
 288         struct nlm_res  *resp = &req->a_res;
 289         struct rpc_message msg = {
 290                 .rpc_argp       = argp,
 291                 .rpc_resp       = resp,
 292         };
 293         int             status;
 294
 295         dprintk("lockd: call procedure %d on %s\n",
 296                         (int)proc, host->h_name);
 297
 298         do {
 299                 if (host->h_reclaiming && !argp->reclaim)
 300                         goto in_grace_period;
 301
 302                 /* If we have no RPC client yet, create one. */
 303                 if ((clnt = nlm_bind_host(host)) == NULL)
 304                         return -ENOLCK;
 305                 msg.rpc_proc = &clnt->cl_procinfo[proc];
 306
 307                 /* Perform the RPC call. If an error occurs, try again */
 308                 if ((status = rpc_call_sync(clnt, &msg, 0)) < 0) {
 309                         dprintk("lockd: rpc_call returned error %d\n", -status);
 310                         switch (status) {
 311                         case -EPROTONOSUPPORT:
 312                                 status = -EINVAL;
 313                                 break;
 314                         case -ECONNREFUSED:
 315                         case -ETIMEDOUT:
 316                         case -ENOTCONN:
 317                                 nlm_rebind_host(host);
 318                                 status = -EAGAIN;
 319                                 break;
 320                         case -ERESTARTSYS:
 321                                 return signalled () ? -EINTR : status;
 322                         default:
 323                                 break;
 324                         }
 325                         break;
 326                 } else
 327                 if (resp->status == nlm_lck_denied_grace_period) {
 328                         dprintk("lockd: server in grace period\n");
 329                         if (argp->reclaim) {
 330                                 printk(KERN_WARNING
 331                                      "lockd: spurious grace period reject?!\n");
 332                                 return -ENOLCK;
 333                         }
 334                 } else {
 335                         if (!argp->reclaim) {
 336                                 /* We appear to be out of the grace period */
 337                                 wake_up_all(&host->h_gracewait);
 338                         }
 339                         dprintk("lockd: server returns status %d\n", resp->status);
 340                         return 0;       /* Okay, call complete */
 341                 }
 342
 343 in_grace_period:
 344                 /*
 345                  * The server has rebooted and appears to be in the grace
 346                  * period during which locks are only allowed to be
 347                  * reclaimed.
 348                  * We can only back off and try again later.
 349                  */
 350                 status = nlm_wait_on_grace(&host->h_gracewait);
 351         } while (status == 0);
 352
 353         return status;
 354 }
 355
 356 /*
 357  * Generic NLM call, async version.
 358  */
 359 static int __nlm_async_call(struct nlm_rqst *req, u32 proc, struct rpc_message *msg, const struct rpc_call_ops *tk_ops)
 360 {
 361         struct nlm_host *host = req->a_host;
 362         struct rpc_clnt *clnt;
 363
 364         dprintk("lockd: call procedure %d on %s (async)\n",
 365                         (int)proc, host->h_name);
 366
 367         /* If we have no RPC client yet, create one. */
 368         clnt = nlm_bind_host(host);
 369         if (clnt == NULL)
 370                 goto out_err;
 371         msg->rpc_proc = &clnt->cl_procinfo[proc];
 372
 373         /* bootstrap and kick off the async RPC call */
 374         return rpc_call_async(clnt, msg, RPC_TASK_ASYNC, tk_ops, req);
 375 out_err:
 376         tk_ops->rpc_release(req);
 377         return -ENOLCK;
 378 }
 379
 380 int nlm_async_call(struct nlm_rqst *req, u32 proc, const struct rpc_call_ops *tk_ops)
 381 {
 382         struct rpc_message msg = {
 383                 .rpc_argp       = &req->a_args,
 384                 .rpc_resp       = &req->a_res,
 385         };
 386         return __nlm_async_call(req, proc, &msg, tk_ops);
 387 }
 388
 389 int nlm_async_reply(struct nlm_rqst *req, u32 proc, const struct rpc_call_ops *tk_ops)
 390 {
 391         struct rpc_message msg = {
 392                 .rpc_argp       = &req->a_res,
 393         };
 394         return __nlm_async_call(req, proc, &msg, tk_ops);
 395 }
 396
 397 /*
 398  * TEST for the presence of a conflicting lock
 399  */
 400 static int
 401 nlmclnt_test(struct nlm_rqst *req, struct file_lock *fl)
 402 {
 403         int     status;
 404
 405         status = nlmclnt_call(req, NLMPROC_TEST);
 406         if (status < 0)
 407                 goto out;
 408
 409         switch (req->a_res.status) {
 410                 case nlm_granted:
 411                         fl->fl_type = F_UNLCK;
 412                         break;
 413                 case nlm_lck_denied:
 414                         /*
 415                          * Report the conflicting lock back to the application.
 416                          */
 417                         fl->fl_start = req->a_res.lock.fl.fl_start;
 418                         fl->fl_end = req->a_res.lock.fl.fl_start;
 419                         fl->fl_type = req->a_res.lock.fl.fl_type;
 420                         fl->fl_pid = 0;
 421                         break;
 422                 default:
 423                         status = nlm_stat_to_errno(req->a_res.status);
 424         }
 425 out:
 426         nlm_release_call(req);
 427         return status;
 428 }
 429
 430 static void nlmclnt_locks_copy_lock(struct file_lock *new, struct file_lock *fl)
 431 {
 432         new->fl_u.nfs_fl.state = fl->fl_u.nfs_fl.state;
 433         new->fl_u.nfs_fl.owner = nlm_get_lockowner(fl->fl_u.nfs_fl.owner);
 434         list_add_tail(&new->fl_u.nfs_fl.list, &fl->fl_u.nfs_fl.owner->host->h_granted);
 435 }
 436
 437 static void nlmclnt_locks_release_private(struct file_lock *fl)
 438 {
 439         list_del(&fl->fl_u.nfs_fl.list);
 440         nlm_put_lockowner(fl->fl_u.nfs_fl.owner);
 441 }
 442
 443 static struct file_lock_operations nlmclnt_lock_ops = {
 444         .fl_copy_lock = nlmclnt_locks_copy_lock,
 445         .fl_release_private = nlmclnt_locks_release_private,
 446 };
 447
 448 static void nlmclnt_locks_init_private(struct file_lock *fl, struct nlm_host *host)
 449 {
 450         BUG_ON(fl->fl_ops != NULL);
 451         fl->fl_u.nfs_fl.state = 0;
 452         fl->fl_u.nfs_fl.owner = nlm_find_lockowner(host, fl->fl_owner);
 453         INIT_LIST_HEAD(&fl->fl_u.nfs_fl.list);
 454         fl->fl_ops = &nlmclnt_lock_ops;
 455 }
 456
 457 static int do_vfs_lock(struct file_lock *fl)
 458 {
 459         int res = 0;
 460         switch (fl->fl_flags & (FL_POSIX|FL_FLOCK)) {
 461                 case FL_POSIX:
 462                         res = posix_lock_file_wait(fl->fl_file, fl);
 463                         break;
 464                 case FL_FLOCK:
 465                         res = flock_lock_file_wait(fl->fl_file, fl);
 466                         break;
 467                 default:
 468                         BUG();
 469         }
 470         return res;
 471 }
 472
 473 /*
 474  * LOCK: Try to create a lock
 475  *
 476  *                      Programmer Harassment Alert
 477  *
 478  * When given a blocking lock request in a sync RPC call, the HPUX lockd
 479  * will faithfully return LCK_BLOCKED but never cares to notify us when
 480  * the lock could be granted. This way, our local process could hang
 481  * around forever waiting for the callback.
 482  *
 483  *  Solution A: Implement busy-waiting
 484  *  Solution B: Use the async version of the call (NLM_LOCK_{MSG,RES})
 485  *
 486  * For now I am implementing solution A, because I hate the idea of
 487  * re-implementing lockd for a third time in two months. The async
 488  * calls shouldn't be too hard to do, however.
 489  *
 490  * This is one of the lovely things about standards in the NFS area:
 491  * they're so soft and squishy you can't really blame HP for doing this.
 492  */
 493 static int
 494 nlmclnt_lock(struct nlm_rqst *req, struct file_lock *fl)
 495 {
 496         struct nlm_host *host = req->a_host;
 497         struct nlm_res  *resp = &req->a_res;
 498         struct nlm_wait *block = NULL;
 499         unsigned char fl_flags = fl->fl_flags;
 500         int status = -ENOLCK;
 501
 502         if (nsm_monitor(host) < 0) {
 503                 printk(KERN_NOTICE "lockd: failed to monitor %s\n",
 504                                         host->h_name);
 505                 goto out;
 506         }
 507         fl->fl_flags |= FL_ACCESS;
 508         status = do_vfs_lock(fl);
 509         if (status < 0)
 510                 goto out;
 511
 512         block = nlmclnt_prepare_block(host, fl);
 513 again:
 514         for(;;) {
 515                 /* Reboot protection */
 516                 fl->fl_u.nfs_fl.state = host->h_state;
 517                 status = nlmclnt_call(req, NLMPROC_LOCK);
 518                 if (status < 0)
 519                         goto out_unblock;
 520                 if (!req->a_args.block)
 521                         break;
 522                 /* Did a reclaimer thread notify us of a server reboot? */
 523                 if (resp->status ==  nlm_lck_denied_grace_period)
 524                         continue;
 525                 if (resp->status != nlm_lck_blocked)
 526                         break;
 527                 /* Wait on an NLM blocking lock */
 528                 status = nlmclnt_block(block, req, NLMCLNT_POLL_TIMEOUT);
 529                 /* if we were interrupted. Send a CANCEL request to the server
 530                  * and exit
 531                  */
 532                 if (status < 0)
 533                         goto out_unblock;
 534                 if (resp->status != nlm_lck_blocked)
 535                         break;
 536         }
 537
 538         if (resp->status == nlm_granted) {
 539                 down_read(&host->h_rwsem);
 540                 /* Check whether or not the server has rebooted */
 541                 if (fl->fl_u.nfs_fl.state != host->h_state) {
 542                         up_read(&host->h_rwsem);
 543                         goto again;
 544                 }
 545                 /* Ensure the resulting lock will get added to granted list */
 546                 fl->fl_flags = fl_flags | FL_SLEEP;
 547                 if (do_vfs_lock(fl) < 0)
 548                         printk(KERN_WARNING "%s: VFS is out of sync with lock manager!\n", __FUNCTION__);
 549                 up_read(&host->h_rwsem);
 550         }
 551         status = nlm_stat_to_errno(resp->status);
 552 out_unblock:
 553         nlmclnt_finish_block(block);
 554         /* Cancel the blocked request if it is still pending */
 555         if (resp->status == nlm_lck_blocked)
 556                 nlmclnt_cancel(host, req->a_args.block, fl);
 557 out:
 558         nlm_release_call(req);
 559         fl->fl_flags = fl_flags;
 560         return status;
 561 }
 562
 563 /*
 564  * RECLAIM: Try to reclaim a lock
 565  */
 566 int
 567 nlmclnt_reclaim(struct nlm_host *host, struct file_lock *fl)
 568 {
 569         struct nlm_rqst reqst, *req;
 570         int             status;
 571
 572         req = &reqst;
 573         memset(req, 0, sizeof(*req));
 574         locks_init_lock(&req->a_args.lock.fl);
 575         locks_init_lock(&req->a_res.lock.fl);
 576         req->a_host  = host;
 577         req->a_flags = 0;
 578
 579         /* Set up the argument struct */
 580         nlmclnt_setlockargs(req, fl);
 581         req->a_args.reclaim = 1;
 582
 583         if ((status = nlmclnt_call(req, NLMPROC_LOCK)) >= 0
 584          && req->a_res.status == nlm_granted)
 585                 return 0;
 586
 587         printk(KERN_WARNING "lockd: failed to reclaim lock for pid %d "
 588                                 "(errno %d, status %d)\n", fl->fl_pid,
 589                                 status, ntohl(req->a_res.status));
 590
 591         /*
 592          * FIXME: This is a serious failure. We can
 593          *
 594          *  a.  Ignore the problem
 595          *  b.  Send the owning process some signal (Linux doesn't have
 596          *      SIGLOST, though...)
 597          *  c.  Retry the operation
 598          *
 599          * Until someone comes up with a simple implementation
 600          * for b or c, I'll choose option a.
 601          */
 602
 603         return -ENOLCK;
 604 }
 605
 606 /*
 607  * UNLOCK: remove an existing lock
 608  */
 609 static int
 610 nlmclnt_unlock(struct nlm_rqst *req, struct file_lock *fl)
 611 {
 612         struct nlm_host *host = req->a_host;
 613         struct nlm_res  *resp = &req->a_res;
 614         int status = 0;
 615
 616         /*
 617          * Note: the server is supposed to either grant us the unlock
 618          * request, or to deny it with NLM_LCK_DENIED_GRACE_PERIOD. In either
 619          * case, we want to unlock.
 620          */
 621         fl->fl_flags |= FL_EXISTS;
 622         down_read(&host->h_rwsem);
 623         if (do_vfs_lock(fl) == -ENOENT) {
 624                 up_read(&host->h_rwsem);
 625                 goto out;
 626         }
 627         up_read(&host->h_rwsem);
 628
 629         if (req->a_flags & RPC_TASK_ASYNC)
 630                 return nlm_async_call(req, NLMPROC_UNLOCK, &nlmclnt_unlock_ops);
 631
 632         status = nlmclnt_call(req, NLMPROC_UNLOCK);
 633         if (status < 0)
 634                 goto out;
 635
 636         if (resp->status == nlm_granted)
 637                 goto out;
 638
 639         if (resp->status != nlm_lck_denied_nolocks)
 640                 printk("lockd: unexpected unlock status: %d\n", resp->status);
 641         /* What to do now? I'm out of my depth... */
 642         status = -ENOLCK;
 643 out:
 644         nlm_release_call(req);
 645         return status;
 646 }
 647
 648 static void nlmclnt_unlock_callback(struct rpc_task *task, void *data)
 649 {
 650         struct nlm_rqst *req = data;
 651         u32 status = ntohl(req->a_res.status);
 652
 653         if (RPC_ASSASSINATED(task))
 654                 goto die;
 655
 656         if (task->tk_status < 0) {
 657                 dprintk("lockd: unlock failed (err = %d)\n", -task->tk_status);
 658                 goto retry_rebind;
 659         }
 660         if (status == NLM_LCK_DENIED_GRACE_PERIOD) {
 661                 rpc_delay(task, NLMCLNT_GRACE_WAIT);
 662                 goto retry_unlock;
 663         }
 664         if (status != NLM_LCK_GRANTED)
 665                 printk(KERN_WARNING "lockd: unexpected unlock status: %d\n", status);
 666 die:
 667         return;
 668  retry_rebind:
 669         nlm_rebind_host(req->a_host);
 670  retry_unlock:
 671         rpc_restart_call(task);
 672 }
 673
 674 static const struct rpc_call_ops nlmclnt_unlock_ops = {
 675         .rpc_call_done = nlmclnt_unlock_callback,
 676         .rpc_release = nlmclnt_rpc_release,
 677 };
 678
 679 /*
 680  * Cancel a blocked lock request.
 681  * We always use an async RPC call for this in order not to hang a
 682  * process that has been Ctrl-C'ed.
 683  */
 684 static int nlmclnt_cancel(struct nlm_host *host, int block, struct file_lock *fl)
 685 {
 686         struct nlm_rqst *req;
 687         unsigned long   flags;
 688         sigset_t        oldset;
 689         int             status;
 690
 691         /* Block all signals while setting up call */
 692         spin_lock_irqsave(&current->sighand->siglock, flags);
 693         oldset = current->blocked;
 694         sigfillset(&current->blocked);
 695         recalc_sigpending();
 696         spin_unlock_irqrestore(&current->sighand->siglock, flags);
 697
 698         req = nlm_alloc_call(nlm_get_host(host));
 699         if (!req)
 700                 return -ENOMEM;
 701         req->a_flags = RPC_TASK_ASYNC;
 702
 703         nlmclnt_setlockargs(req, fl);
 704         req->a_args.block = block;
 705
 706         status = nlm_async_call(req, NLMPROC_CANCEL, &nlmclnt_cancel_ops);
 707
 708         spin_lock_irqsave(&current->sighand->siglock, flags);
 709         current->blocked = oldset;
 710         recalc_sigpending();
 711         spin_unlock_irqrestore(&current->sighand->siglock, flags);
 712
 713         return status;
 714 }
 715
 716 static void nlmclnt_cancel_callback(struct rpc_task *task, void *data)
 717 {
 718         struct nlm_rqst *req = data;
 719         u32 status = ntohl(req->a_res.status);
 720
 721         if (RPC_ASSASSINATED(task))
 722                 goto die;
 723
 724         if (task->tk_status < 0) {
 725                 dprintk("lockd: CANCEL call error %d, retrying.\n",
 726                                         task->tk_status);
 727                 goto retry_cancel;
 728         }
 729
 730         dprintk("lockd: cancel status %u (task %u)\n",
 731                         status, task->tk_pid);
 732
 733         switch (status) {
 734         case NLM_LCK_GRANTED:
 735         case NLM_LCK_DENIED_GRACE_PERIOD:
 736         case NLM_LCK_DENIED:
 737                 /* Everything's good */
 738                 break;
 739         case NLM_LCK_DENIED_NOLOCKS:
 740                 dprintk("lockd: CANCEL failed (server has no locks)\n");
 741                 goto retry_cancel;
 742         default:
 743                 printk(KERN_NOTICE "lockd: weird return %d for CANCEL call\n",
 744                         status);
 745         }
 746
 747 die:
 748         return;
 749
 750 retry_cancel:
 751         /* Don't ever retry more than 3 times */
 752         if (req->a_retries++ >= NLMCLNT_MAX_RETRIES)
 753                 goto die;
 754         nlm_rebind_host(req->a_host);
 755         rpc_restart_call(task);
 756         rpc_delay(task, 30 * HZ);
 757 }
 758
 759 static const struct rpc_call_ops nlmclnt_cancel_ops = {
 760         .rpc_call_done = nlmclnt_cancel_callback,
 761         .rpc_release = nlmclnt_rpc_release,
 762 };
 763
 764 /*
 765  * Convert an NLM status code to a generic kernel errno
 766  */
 767 static int
 768 nlm_stat_to_errno(__be32 status)
 769 {
 770         switch(ntohl(status)) {
 771         case NLM_LCK_GRANTED:
 772                 return 0;
 773         case NLM_LCK_DENIED:
 774                 return -EAGAIN;
 775         case NLM_LCK_DENIED_NOLOCKS:
 776         case NLM_LCK_DENIED_GRACE_PERIOD:
 777                 return -ENOLCK;
 778         case NLM_LCK_BLOCKED:
 779                 printk(KERN_NOTICE "lockd: unexpected status NLM_BLOCKED\n");
 780                 return -ENOLCK;
 781 #ifdef CONFIG_LOCKD_V4
 782         case NLM_DEADLCK:
 783                 return -EDEADLK;
 784         case NLM_ROFS:
 785                 return -EROFS;
 786         case NLM_STALE_FH:
 787                 return -ESTALE;
 788         case NLM_FBIG:
 789                 return -EOVERFLOW;
 790         case NLM_FAILED:
 791                 return -ENOLCK;
 792 #endif
 793         }
 794         printk(KERN_NOTICE "lockd: unexpected server status %d\n", status);
 795         return -ENOLCK;
 796 }