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/smp_lock.h>
  16 #include <linux/freezer.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 atomic_t nlm_cookie = ATOMIC_INIT(0x1234);
  41
  42 void nlmclnt_next_cookie(struct nlm_cookie *c)
  43 {
  44         u32     cookie = atomic_inc_return(&nlm_cookie);
  45
  46         memcpy(c->data, &cookie, 4);
  47         c->len=4;
  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 = 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_path.dentry->d_inode), sizeof(struct nfs_fh));
 133         lock->caller  = 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                                 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 rpc_clnt         *client = NFS_CLIENT(inode);
 156         struct sockaddr_in      addr;
 157         struct nfs_server       *nfssrv = NFS_SERVER(inode);
 158         struct nlm_host         *host;
 159         struct nlm_rqst         *call;
 160         sigset_t                oldset;
 161         unsigned long           flags;
 162         int                     status, vers;
 163
 164         vers = (NFS_PROTO(inode)->version == 3) ? 4 : 1;
 165         if (NFS_PROTO(inode)->version > 3) {
 166                 printk(KERN_NOTICE "NFSv4 file locking not implemented!\n");
 167                 return -ENOLCK;
 168         }
 169
 170         rpc_peeraddr(client, (struct sockaddr *) &addr, sizeof(addr));
 171         host = nlmclnt_lookup_host(&addr, client->cl_xprt->prot, vers,
 172                                    nfssrv->nfs_client->cl_hostname,
 173                                    strlen(nfssrv->nfs_client->cl_hostname));
 174         if (host == NULL)
 175                 return -ENOLCK;
 176
 177         call = nlm_alloc_call(host);
 178         if (call == NULL)
 179                 return -ENOMEM;
 180
 181         nlmclnt_locks_init_private(fl, host);
 182         /* Set up the argument struct */
 183         nlmclnt_setlockargs(call, fl);
 184
 185         /* Keep the old signal mask */
 186         spin_lock_irqsave(&current->sighand->siglock, flags);
 187         oldset = current->blocked;
 188
 189         /* If we're cleaning up locks because the process is exiting,
 190          * perform the RPC call asynchronously. */
 191         if ((IS_SETLK(cmd) || IS_SETLKW(cmd))
 192             && fl->fl_type == F_UNLCK
 193             && (current->flags & PF_EXITING)) {
 194                 sigfillset(&current->blocked);  /* Mask all signals */
 195                 recalc_sigpending();
 196
 197                 call->a_flags = RPC_TASK_ASYNC;
 198         }
 199         spin_unlock_irqrestore(&current->sighand->siglock, flags);
 200
 201         if (IS_SETLK(cmd) || IS_SETLKW(cmd)) {
 202                 if (fl->fl_type != F_UNLCK) {
 203                         call->a_args.block = IS_SETLKW(cmd) ? 1 : 0;
 204                         status = nlmclnt_lock(call, fl);
 205                 } else
 206                         status = nlmclnt_unlock(call, fl);
 207         } else if (IS_GETLK(cmd))
 208                 status = nlmclnt_test(call, fl);
 209         else
 210                 status = -EINVAL;
 211
 212         fl->fl_ops->fl_release_private(fl);
 213         fl->fl_ops = NULL;
 214
 215         spin_lock_irqsave(&current->sighand->siglock, flags);
 216         current->blocked = oldset;
 217         recalc_sigpending();
 218         spin_unlock_irqrestore(&current->sighand->siglock, flags);
 219
 220         dprintk("lockd: clnt proc returns %d\n", status);
 221         return status;
 222 }
 223 EXPORT_SYMBOL(nlmclnt_proc);
 224
 225 /*
 226  * Allocate an NLM RPC call struct
 227  *
 228  * Note: the caller must hold a reference to host. In case of failure,
 229  * this reference will be released.
 230  */
 231 struct nlm_rqst *nlm_alloc_call(struct nlm_host *host)
 232 {
 233         struct nlm_rqst *call;
 234
 235         for(;;) {
 236                 call = kzalloc(sizeof(*call), GFP_KERNEL);
 237                 if (call != NULL) {
 238                         locks_init_lock(&call->a_args.lock.fl);
 239                         locks_init_lock(&call->a_res.lock.fl);
 240                         call->a_host = host;
 241                         return call;
 242                 }
 243                 if (signalled())
 244                         break;
 245                 printk("nlm_alloc_call: failed, waiting for memory\n");
 246                 schedule_timeout_interruptible(5*HZ);
 247         }
 248         nlm_release_host(host);
 249         return NULL;
 250 }
 251
 252 void nlm_release_call(struct nlm_rqst *call)
 253 {
 254         nlm_release_host(call->a_host);
 255         nlmclnt_release_lockargs(call);
 256         kfree(call);
 257 }
 258
 259 static void nlmclnt_rpc_release(void *data)
 260 {
 261         return nlm_release_call(data);
 262 }
 263
 264 static int nlm_wait_on_grace(wait_queue_head_t *queue)
 265 {
 266         DEFINE_WAIT(wait);
 267         int status = -EINTR;
 268
 269         prepare_to_wait(queue, &wait, TASK_INTERRUPTIBLE);
 270         if (!signalled ()) {
 271                 schedule_timeout(NLMCLNT_GRACE_WAIT);
 272                 try_to_freeze();
 273                 if (!signalled ())
 274                         status = 0;
 275         }
 276         finish_wait(queue, &wait);
 277         return status;
 278 }
 279
 280 /*
 281  * Generic NLM call
 282  */
 283 static int
 284 nlmclnt_call(struct nlm_rqst *req, u32 proc)
 285 {
 286         struct nlm_host *host = req->a_host;
 287         struct rpc_clnt *clnt;
 288         struct nlm_args *argp = &req->a_args;
 289         struct nlm_res  *resp = &req->a_res;
 290         struct rpc_message msg = {
 291                 .rpc_argp       = argp,
 292                 .rpc_resp       = resp,
 293         };
 294         int             status;
 295
 296         dprintk("lockd: call procedure %d on %s\n",
 297                         (int)proc, host->h_name);
 298
 299         do {
 300                 if (host->h_reclaiming && !argp->reclaim)
 301                         goto in_grace_period;
 302
 303                 /* If we have no RPC client yet, create one. */
 304                 if ((clnt = nlm_bind_host(host)) == NULL)
 305                         return -ENOLCK;
 306                 msg.rpc_proc = &clnt->cl_procinfo[proc];
 307
 308                 /* Perform the RPC call. If an error occurs, try again */
 309                 if ((status = rpc_call_sync(clnt, &msg, 0)) < 0) {
 310                         dprintk("lockd: rpc_call returned error %d\n", -status);
 311                         switch (status) {
 312                         case -EPROTONOSUPPORT:
 313                                 status = -EINVAL;
 314                                 break;
 315                         case -ECONNREFUSED:
 316                         case -ETIMEDOUT:
 317                         case -ENOTCONN:
 318                                 nlm_rebind_host(host);
 319                                 status = -EAGAIN;
 320                                 break;
 321                         case -ERESTARTSYS:
 322                                 return signalled () ? -EINTR : status;
 323                         default:
 324                                 break;
 325                         }
 326                         break;
 327                 } else
 328                 if (resp->status == NLM_LCK_DENIED_GRACE_PERIOD) {
 329                         dprintk("lockd: server in grace period\n");
 330                         if (argp->reclaim) {
 331                                 printk(KERN_WARNING
 332                                      "lockd: spurious grace period reject?!\n");
 333                                 return -ENOLCK;
 334                         }
 335                 } else {
 336                         if (!argp->reclaim) {
 337                                 /* We appear to be out of the grace period */
 338                                 wake_up_all(&host->h_gracewait);
 339                         }
 340                         dprintk("lockd: server returns status %d\n", resp->status);
 341                         return 0;       /* Okay, call complete */
 342                 }
 343
 344 in_grace_period:
 345                 /*
 346                  * The server has rebooted and appears to be in the grace
 347                  * period during which locks are only allowed to be
 348                  * reclaimed.
 349                  * We can only back off and try again later.
 350                  */
 351                 status = nlm_wait_on_grace(&host->h_gracewait);
 352         } while (status == 0);
 353
 354         return status;
 355 }
 356
 357 /*
 358  * Generic NLM call, async version.
 359  */
 360 static int __nlm_async_call(struct nlm_rqst *req, u32 proc, struct rpc_message *msg, const struct rpc_call_ops *tk_ops)
 361 {
 362         struct nlm_host *host = req->a_host;
 363         struct rpc_clnt *clnt;
 364         int status = -ENOLCK;
 365
 366         dprintk("lockd: call procedure %d on %s (async)\n",
 367                         (int)proc, host->h_name);
 368
 369         /* If we have no RPC client yet, create one. */
 370         clnt = nlm_bind_host(host);
 371         if (clnt == NULL)
 372                 goto out_err;
 373         msg->rpc_proc = &clnt->cl_procinfo[proc];
 374
 375         /* bootstrap and kick off the async RPC call */
 376         status = rpc_call_async(clnt, msg, RPC_TASK_ASYNC, tk_ops, req);
 377         if (status == 0)
 378                 return 0;
 379 out_err:
 380         nlm_release_call(req);
 381         return status;
 382 }
 383
 384 int nlm_async_call(struct nlm_rqst *req, u32 proc, const struct rpc_call_ops *tk_ops)
 385 {
 386         struct rpc_message msg = {
 387                 .rpc_argp       = &req->a_args,
 388                 .rpc_resp       = &req->a_res,
 389         };
 390         return __nlm_async_call(req, proc, &msg, tk_ops);
 391 }
 392
 393 int nlm_async_reply(struct nlm_rqst *req, u32 proc, const struct rpc_call_ops *tk_ops)
 394 {
 395         struct rpc_message msg = {
 396                 .rpc_argp       = &req->a_res,
 397         };
 398         return __nlm_async_call(req, proc, &msg, tk_ops);
 399 }
 400
 401 /*
 402  * TEST for the presence of a conflicting lock
 403  */
 404 static int
 405 nlmclnt_test(struct nlm_rqst *req, struct file_lock *fl)
 406 {
 407         int     status;
 408
 409         status = nlmclnt_call(req, NLMPROC_TEST);
 410         if (status < 0)
 411                 goto out;
 412
 413         switch (req->a_res.status) {
 414                 case NLM_LCK_GRANTED:
 415                         fl->fl_type = F_UNLCK;
 416                         break;
 417                 case NLM_LCK_DENIED:
 418                         /*
 419                          * Report the conflicting lock back to the application.
 420                          */
 421                         fl->fl_start = req->a_res.lock.fl.fl_start;
 422                         fl->fl_end = req->a_res.lock.fl.fl_start;
 423                         fl->fl_type = req->a_res.lock.fl.fl_type;
 424                         fl->fl_pid = 0;
 425                         break;
 426                 default:
 427                         status = nlm_stat_to_errno(req->a_res.status);
 428         }
 429 out:
 430         nlm_release_call(req);
 431         return status;
 432 }
 433
 434 static void nlmclnt_locks_copy_lock(struct file_lock *new, struct file_lock *fl)
 435 {
 436         new->fl_u.nfs_fl.state = fl->fl_u.nfs_fl.state;
 437         new->fl_u.nfs_fl.owner = nlm_get_lockowner(fl->fl_u.nfs_fl.owner);
 438         list_add_tail(&new->fl_u.nfs_fl.list, &fl->fl_u.nfs_fl.owner->host->h_granted);
 439 }
 440
 441 static void nlmclnt_locks_release_private(struct file_lock *fl)
 442 {
 443         list_del(&fl->fl_u.nfs_fl.list);
 444         nlm_put_lockowner(fl->fl_u.nfs_fl.owner);
 445 }
 446
 447 static struct file_lock_operations nlmclnt_lock_ops = {
 448         .fl_copy_lock = nlmclnt_locks_copy_lock,
 449         .fl_release_private = nlmclnt_locks_release_private,
 450 };
 451
 452 static void nlmclnt_locks_init_private(struct file_lock *fl, struct nlm_host *host)
 453 {
 454         BUG_ON(fl->fl_ops != NULL);
 455         fl->fl_u.nfs_fl.state = 0;
 456         fl->fl_u.nfs_fl.owner = nlm_find_lockowner(host, fl->fl_owner);
 457         INIT_LIST_HEAD(&fl->fl_u.nfs_fl.list);
 458         fl->fl_ops = &nlmclnt_lock_ops;
 459 }
 460
 461 static int do_vfs_lock(struct file_lock *fl)
 462 {
 463         int res = 0;
 464         switch (fl->fl_flags & (FL_POSIX|FL_FLOCK)) {
 465                 case FL_POSIX:
 466                         res = posix_lock_file_wait(fl->fl_file, fl);
 467                         break;
 468                 case FL_FLOCK:
 469                         res = flock_lock_file_wait(fl->fl_file, fl);
 470                         break;
 471                 default:
 472                         BUG();
 473         }
 474         return res;
 475 }
 476
 477 /*
 478  * LOCK: Try to create a lock
 479  *
 480  *                      Programmer Harassment Alert
 481  *
 482  * When given a blocking lock request in a sync RPC call, the HPUX lockd
 483  * will faithfully return LCK_BLOCKED but never cares to notify us when
 484  * the lock could be granted. This way, our local process could hang
 485  * around forever waiting for the callback.
 486  *
 487  *  Solution A: Implement busy-waiting
 488  *  Solution B: Use the async version of the call (NLM_LOCK_{MSG,RES})
 489  *
 490  * For now I am implementing solution A, because I hate the idea of
 491  * re-implementing lockd for a third time in two months. The async
 492  * calls shouldn't be too hard to do, however.
 493  *
 494  * This is one of the lovely things about standards in the NFS area:
 495  * they're so soft and squishy you can't really blame HP for doing this.
 496  */
 497 static int
 498 nlmclnt_lock(struct nlm_rqst *req, struct file_lock *fl)
 499 {
 500         struct nlm_host *host = req->a_host;
 501         struct nlm_res  *resp = &req->a_res;
 502         struct nlm_wait *block = NULL;
 503         unsigned char fl_flags = fl->fl_flags;
 504         int status = -ENOLCK;
 505
 506         if (nsm_monitor(host) < 0) {
 507                 printk(KERN_NOTICE "lockd: failed to monitor %s\n",
 508                                         host->h_name);
 509                 goto out;
 510         }
 511         fl->fl_flags |= FL_ACCESS;
 512         status = do_vfs_lock(fl);
 513         if (status < 0)
 514                 goto out;
 515
 516         block = nlmclnt_prepare_block(host, fl);
 517 again:
 518         for(;;) {
 519                 /* Reboot protection */
 520                 fl->fl_u.nfs_fl.state = host->h_state;
 521                 status = nlmclnt_call(req, NLMPROC_LOCK);
 522                 if (status < 0)
 523                         goto out_unblock;
 524                 if (!req->a_args.block)
 525                         break;
 526                 /* Did a reclaimer thread notify us of a server reboot? */
 527                 if (resp->status ==  NLM_LCK_DENIED_GRACE_PERIOD)
 528                         continue;
 529                 if (resp->status != NLM_LCK_BLOCKED)
 530                         break;
 531                 /* Wait on an NLM blocking lock */
 532                 status = nlmclnt_block(block, req, NLMCLNT_POLL_TIMEOUT);
 533                 /* if we were interrupted. Send a CANCEL request to the server
 534                  * and exit
 535                  */
 536                 if (status < 0)
 537                         goto out_unblock;
 538                 if (resp->status != NLM_LCK_BLOCKED)
 539                         break;
 540         }
 541
 542         if (resp->status == NLM_LCK_GRANTED) {
 543                 down_read(&host->h_rwsem);
 544                 /* Check whether or not the server has rebooted */
 545                 if (fl->fl_u.nfs_fl.state != host->h_state) {
 546                         up_read(&host->h_rwsem);
 547                         goto again;
 548                 }
 549                 /* Ensure the resulting lock will get added to granted list */
 550                 fl->fl_flags = fl_flags | FL_SLEEP;
 551                 if (do_vfs_lock(fl) < 0)
 552                         printk(KERN_WARNING "%s: VFS is out of sync with lock manager!\n", __FUNCTION__);
 553                 up_read(&host->h_rwsem);
 554         }
 555         status = nlm_stat_to_errno(resp->status);
 556 out_unblock:
 557         nlmclnt_finish_block(block);
 558         /* Cancel the blocked request if it is still pending */
 559         if (resp->status == NLM_LCK_BLOCKED)
 560                 nlmclnt_cancel(host, req->a_args.block, fl);
 561 out:
 562         nlm_release_call(req);
 563         fl->fl_flags = fl_flags;
 564         return status;
 565 }
 566
 567 /*
 568  * RECLAIM: Try to reclaim a lock
 569  */
 570 int
 571 nlmclnt_reclaim(struct nlm_host *host, struct file_lock *fl)
 572 {
 573         struct nlm_rqst reqst, *req;
 574         int             status;
 575
 576         req = &reqst;
 577         memset(req, 0, sizeof(*req));
 578         locks_init_lock(&req->a_args.lock.fl);
 579         locks_init_lock(&req->a_res.lock.fl);
 580         req->a_host  = host;
 581         req->a_flags = 0;
 582
 583         /* Set up the argument struct */
 584         nlmclnt_setlockargs(req, fl);
 585         req->a_args.reclaim = 1;
 586
 587         if ((status = nlmclnt_call(req, NLMPROC_LOCK)) >= 0
 588          && req->a_res.status == NLM_LCK_GRANTED)
 589                 return 0;
 590
 591         printk(KERN_WARNING "lockd: failed to reclaim lock for pid %d "
 592                                 "(errno %d, status %d)\n", fl->fl_pid,
 593                                 status, req->a_res.status);
 594
 595         /*
 596          * FIXME: This is a serious failure. We can
 597          *
 598          *  a.  Ignore the problem
 599          *  b.  Send the owning process some signal (Linux doesn't have
 600          *      SIGLOST, though...)
 601          *  c.  Retry the operation
 602          *
 603          * Until someone comes up with a simple implementation
 604          * for b or c, I'll choose option a.
 605          */
 606
 607         return -ENOLCK;
 608 }
 609
 610 /*
 611  * UNLOCK: remove an existing lock
 612  */
 613 static int
 614 nlmclnt_unlock(struct nlm_rqst *req, struct file_lock *fl)
 615 {
 616         struct nlm_host *host = req->a_host;
 617         struct nlm_res  *resp = &req->a_res;
 618         int status = 0;
 619
 620         /*
 621          * Note: the server is supposed to either grant us the unlock
 622          * request, or to deny it with NLM_LCK_DENIED_GRACE_PERIOD. In either
 623          * case, we want to unlock.
 624          */
 625         fl->fl_flags |= FL_EXISTS;
 626         down_read(&host->h_rwsem);
 627         if (do_vfs_lock(fl) == -ENOENT) {
 628                 up_read(&host->h_rwsem);
 629                 goto out;
 630         }
 631         up_read(&host->h_rwsem);
 632
 633         if (req->a_flags & RPC_TASK_ASYNC)
 634                 return nlm_async_call(req, NLMPROC_UNLOCK, &nlmclnt_unlock_ops);
 635
 636         status = nlmclnt_call(req, NLMPROC_UNLOCK);
 637         if (status < 0)
 638                 goto out;
 639
 640         if (resp->status == NLM_LCK_GRANTED)
 641                 goto out;
 642
 643         if (resp->status != NLM_LCK_DENIED_NOLOCKS)
 644                 printk("lockd: unexpected unlock status: %d\n", resp->status);
 645         /* What to do now? I'm out of my depth... */
 646         status = -ENOLCK;
 647 out:
 648         nlm_release_call(req);
 649         return status;
 650 }
 651
 652 static void nlmclnt_unlock_callback(struct rpc_task *task, void *data)
 653 {
 654         struct nlm_rqst *req = data;
 655         int             status = req->a_res.status;
 656
 657         if (RPC_ASSASSINATED(task))
 658                 goto die;
 659
 660         if (task->tk_status < 0) {
 661                 dprintk("lockd: unlock failed (err = %d)\n", -task->tk_status);
 662                 goto retry_rebind;
 663         }
 664         if (status == NLM_LCK_DENIED_GRACE_PERIOD) {
 665                 rpc_delay(task, NLMCLNT_GRACE_WAIT);
 666                 goto retry_unlock;
 667         }
 668         if (status != NLM_LCK_GRANTED)
 669                 printk(KERN_WARNING "lockd: unexpected unlock status: %d\n", status);
 670 die:
 671         return;
 672  retry_rebind:
 673         nlm_rebind_host(req->a_host);
 674  retry_unlock:
 675         rpc_restart_call(task);
 676 }
 677
 678 static const struct rpc_call_ops nlmclnt_unlock_ops = {
 679         .rpc_call_done = nlmclnt_unlock_callback,
 680         .rpc_release = nlmclnt_rpc_release,
 681 };
 682
 683 /*
 684  * Cancel a blocked lock request.
 685  * We always use an async RPC call for this in order not to hang a
 686  * process that has been Ctrl-C'ed.
 687  */
 688 static int nlmclnt_cancel(struct nlm_host *host, int block, struct file_lock *fl)
 689 {
 690         struct nlm_rqst *req;
 691         unsigned long   flags;
 692         sigset_t        oldset;
 693         int             status;
 694
 695         /* Block all signals while setting up call */
 696         spin_lock_irqsave(&current->sighand->siglock, flags);
 697         oldset = current->blocked;
 698         sigfillset(&current->blocked);
 699         recalc_sigpending();
 700         spin_unlock_irqrestore(&current->sighand->siglock, flags);
 701
 702         req = nlm_alloc_call(nlm_get_host(host));
 703         if (!req)
 704                 return -ENOMEM;
 705         req->a_flags = RPC_TASK_ASYNC;
 706
 707         nlmclnt_setlockargs(req, fl);
 708         req->a_args.block = block;
 709
 710         status = nlm_async_call(req, NLMPROC_CANCEL, &nlmclnt_cancel_ops);
 711
 712         spin_lock_irqsave(&current->sighand->siglock, flags);
 713         current->blocked = oldset;
 714         recalc_sigpending();
 715         spin_unlock_irqrestore(&current->sighand->siglock, flags);
 716
 717         return status;
 718 }
 719
 720 static void nlmclnt_cancel_callback(struct rpc_task *task, void *data)
 721 {
 722         struct nlm_rqst *req = data;
 723
 724         if (RPC_ASSASSINATED(task))
 725                 goto die;
 726
 727         if (task->tk_status < 0) {
 728                 dprintk("lockd: CANCEL call error %d, retrying.\n",
 729                                         task->tk_status);
 730                 goto retry_cancel;
 731         }
 732
 733         dprintk("lockd: cancel status %u (task %u)\n",
 734                         req->a_res.status, task->tk_pid);
 735
 736         switch (req->a_res.status) {
 737         case NLM_LCK_GRANTED:
 738         case NLM_LCK_DENIED_GRACE_PERIOD:
 739         case NLM_LCK_DENIED:
 740                 /* Everything's good */
 741                 break;
 742         case NLM_LCK_DENIED_NOLOCKS:
 743                 dprintk("lockd: CANCEL failed (server has no locks)\n");
 744                 goto retry_cancel;
 745         default:
 746                 printk(KERN_NOTICE "lockd: weird return %d for CANCEL call\n",
 747                         req->a_res.status);
 748         }
 749
 750 die:
 751         return;
 752
 753 retry_cancel:
 754         /* Don't ever retry more than 3 times */
 755         if (req->a_retries++ >= NLMCLNT_MAX_RETRIES)
 756                 goto die;
 757         nlm_rebind_host(req->a_host);
 758         rpc_restart_call(task);
 759         rpc_delay(task, 30 * HZ);
 760 }
 761
 762 static const struct rpc_call_ops nlmclnt_cancel_ops = {
 763         .rpc_call_done = nlmclnt_cancel_callback,
 764         .rpc_release = nlmclnt_rpc_release,
 765 };
 766
 767 /*
 768  * Convert an NLM status code to a generic kernel errno
 769  */
 770 static int
 771 nlm_stat_to_errno(u32 status)
 772 {
 773         switch(status) {
 774         case NLM_LCK_GRANTED:
 775                 return 0;
 776         case NLM_LCK_DENIED:
 777                 return -EAGAIN;
 778         case NLM_LCK_DENIED_NOLOCKS:
 779         case NLM_LCK_DENIED_GRACE_PERIOD:
 780                 return -ENOLCK;
 781         case NLM_LCK_BLOCKED:
 782                 printk(KERN_NOTICE "lockd: unexpected status NLM_BLOCKED\n");
 783                 return -ENOLCK;
 784 #ifdef CONFIG_LOCKD_V4
 785         case NLM_DEADLCK:
 786                 return -EDEADLK;
 787         case NLM_ROFS:
 788                 return -EROFS;
 789         case NLM_STALE_FH:
 790                 return -ESTALE;
 791         case NLM_FBIG:
 792                 return -EOVERFLOW;
 793         case NLM_FAILED:
 794                 return -ENOLCK;
 795 #endif
 796         }
 797         printk(KERN_NOTICE "lockd: unexpected server status %d\n", status);
 798         return -ENOLCK;
 799 }