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 #include <linux/vs_base.h>
  22 #include <linux/vs_cvirt.h>
  23
  24 #define NLMDBG_FACILITY         NLMDBG_CLIENT
  25 #define NLMCLNT_GRACE_WAIT      (5*HZ)
  26 #define NLMCLNT_POLL_TIMEOUT    (30*HZ)
  27 #define NLMCLNT_MAX_RETRIES     3
  28
  29 static int      nlmclnt_test(struct nlm_rqst *, struct file_lock *);
  30 static int      nlmclnt_lock(struct nlm_rqst *, struct file_lock *);
  31 static int      nlmclnt_unlock(struct nlm_rqst *, struct file_lock *);
  32 static int      nlm_stat_to_errno(u32 stat);
  33 static void     nlmclnt_locks_init_private(struct file_lock *fl, struct nlm_host *host);
  34 static int      nlmclnt_cancel(struct nlm_host *, int , struct file_lock *);
  35
  36 static const struct rpc_call_ops nlmclnt_unlock_ops;
  37 static const struct rpc_call_ops nlmclnt_cancel_ops;
  38
  39 /*
  40  * Cookie counter for NLM requests
  41  */
  42 static u32      nlm_cookie = 0x1234;
  43
  44 static inline void nlmclnt_next_cookie(struct nlm_cookie *c)
  45 {
  46         memcpy(c->data, &nlm_cookie, 4);
  47         memset(c->data+4, 0, 4);
  48         c->len=4;
  49         nlm_cookie++;
  50 }
  51
  52 static struct nlm_lockowner *nlm_get_lockowner(struct nlm_lockowner *lockowner)
  53 {
  54         atomic_inc(&lockowner->count);
  55         return lockowner;
  56 }
  57
  58 static void nlm_put_lockowner(struct nlm_lockowner *lockowner)
  59 {
  60         if (!atomic_dec_and_lock(&lockowner->count, &lockowner->host->h_lock))
  61                 return;
  62         list_del(&lockowner->list);
  63         spin_unlock(&lockowner->host->h_lock);
  64         nlm_release_host(lockowner->host);
  65         kfree(lockowner);
  66 }
  67
  68 static inline int nlm_pidbusy(struct nlm_host *host, uint32_t pid)
  69 {
  70         struct nlm_lockowner *lockowner;
  71         list_for_each_entry(lockowner, &host->h_lockowners, list) {
  72                 if (lockowner->pid == pid)
  73                         return -EBUSY;
  74         }
  75         return 0;
  76 }
  77
  78 static inline uint32_t __nlm_alloc_pid(struct nlm_host *host)
  79 {
  80         uint32_t res;
  81         do {
  82                 res = host->h_pidcount++;
  83         } while (nlm_pidbusy(host, res) < 0);
  84         return res;
  85 }
  86
  87 static struct nlm_lockowner *__nlm_find_lockowner(struct nlm_host *host, fl_owner_t owner)
  88 {
  89         struct nlm_lockowner *lockowner;
  90         list_for_each_entry(lockowner, &host->h_lockowners, list) {
  91                 if (lockowner->owner != owner)
  92                         continue;
  93                 return nlm_get_lockowner(lockowner);
  94         }
  95         return NULL;
  96 }
  97
  98 static struct nlm_lockowner *nlm_find_lockowner(struct nlm_host *host, fl_owner_t owner)
  99 {
 100         struct nlm_lockowner *res, *new = NULL;
 101
 102         spin_lock(&host->h_lock);
 103         res = __nlm_find_lockowner(host, owner);
 104         if (res == NULL) {
 105                 spin_unlock(&host->h_lock);
 106                 new = (struct nlm_lockowner *)kmalloc(sizeof(*new), GFP_KERNEL);
 107                 spin_lock(&host->h_lock);
 108                 res = __nlm_find_lockowner(host, owner);
 109                 if (res == NULL && new != NULL) {
 110                         res = new;
 111                         atomic_set(&new->count, 1);
 112                         new->owner = owner;
 113                         new->pid = __nlm_alloc_pid(host);
 114                         new->host = nlm_get_host(host);
 115                         list_add(&new->list, &host->h_lockowners);
 116                         new = NULL;
 117                 }
 118         }
 119         spin_unlock(&host->h_lock);
 120         kfree(new);
 121         return res;
 122 }
 123
 124 /*
 125  * Initialize arguments for TEST/LOCK/UNLOCK/CANCEL calls
 126  */
 127 static void nlmclnt_setlockargs(struct nlm_rqst *req, struct file_lock *fl)
 128 {
 129         struct nlm_args *argp = &req->a_args;
 130         struct nlm_lock *lock = &argp->lock;
 131
 132         nlmclnt_next_cookie(&argp->cookie);
 133         argp->state   = nsm_local_state;
 134         memcpy(&lock->fh, NFS_FH(fl->fl_file->f_dentry->d_inode), sizeof(struct nfs_fh));
 135         lock->caller  = vx_new_uts(nodename);
 136         lock->oh.data = req->a_owner;
 137         lock->oh.len  = snprintf(req->a_owner, sizeof(req->a_owner), "%u@%s",
 138                                 (unsigned int)fl->fl_u.nfs_fl.owner->pid,
 139                                 vx_new_uts(nodename));
 140         lock->svid = fl->fl_u.nfs_fl.owner->pid;
 141         lock->fl.fl_start = fl->fl_start;
 142         lock->fl.fl_end = fl->fl_end;
 143         lock->fl.fl_type = fl->fl_type;
 144 }
 145
 146 static void nlmclnt_release_lockargs(struct nlm_rqst *req)
 147 {
 148         BUG_ON(req->a_args.lock.fl.fl_ops != NULL);
 149 }
 150
 151 /*
 152  * This is the main entry point for the NLM client.
 153  */
 154 int
 155 nlmclnt_proc(struct inode *inode, int cmd, struct file_lock *fl)
 156 {
 157         struct nlm_host         *host;
 158         struct nlm_rqst         *call;
 159         sigset_t                oldset;
 160         unsigned long           flags;
 161         int                     status, proto, 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         /* Retrieve transport protocol from NFS client */
 170         proto = NFS_CLIENT(inode)->cl_xprt->prot;
 171
 172         host = nlmclnt_lookup_host(NFS_ADDR(inode), proto, vers);
 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         int status = -ENOLCK;
 364
 365         dprintk("lockd: call procedure %d on %s (async)\n",
 366                         (int)proc, host->h_name);
 367
 368         /* If we have no RPC client yet, create one. */
 369         clnt = nlm_bind_host(host);
 370         if (clnt == NULL)
 371                 goto out_err;
 372         msg->rpc_proc = &clnt->cl_procinfo[proc];
 373
 374         /* bootstrap and kick off the async RPC call */
 375         status = rpc_call_async(clnt, msg, RPC_TASK_ASYNC, tk_ops, req);
 376         if (status == 0)
 377                 return 0;
 378 out_err:
 379         nlm_release_call(req);
 380         return status;
 381 }
 382
 383 int nlm_async_call(struct nlm_rqst *req, u32 proc, const struct rpc_call_ops *tk_ops)
 384 {
 385         struct rpc_message msg = {
 386                 .rpc_argp       = &req->a_args,
 387                 .rpc_resp       = &req->a_res,
 388         };
 389         return __nlm_async_call(req, proc, &msg, tk_ops);
 390 }
 391
 392 int nlm_async_reply(struct nlm_rqst *req, u32 proc, const struct rpc_call_ops *tk_ops)
 393 {
 394         struct rpc_message msg = {
 395                 .rpc_argp       = &req->a_res,
 396         };
 397         return __nlm_async_call(req, proc, &msg, tk_ops);
 398 }
 399
 400 /*
 401  * TEST for the presence of a conflicting lock
 402  */
 403 static int
 404 nlmclnt_test(struct nlm_rqst *req, struct file_lock *fl)
 405 {
 406         int     status;
 407
 408         status = nlmclnt_call(req, NLMPROC_TEST);
 409         if (status < 0)
 410                 goto out;
 411
 412         switch (req->a_res.status) {
 413                 case NLM_LCK_GRANTED:
 414                         fl->fl_type = F_UNLCK;
 415                         break;
 416                 case NLM_LCK_DENIED:
 417                         /*
 418                          * Report the conflicting lock back to the application.
 419                          */
 420                         fl->fl_start = req->a_res.lock.fl.fl_start;
 421                         fl->fl_end = req->a_res.lock.fl.fl_start;
 422                         fl->fl_type = req->a_res.lock.fl.fl_type;
 423                         fl->fl_pid = 0;
 424                         break;
 425                 default:
 426                         status = nlm_stat_to_errno(req->a_res.status);
 427         }
 428 out:
 429         nlm_release_call(req);
 430         return status;
 431 }
 432
 433 static void nlmclnt_locks_copy_lock(struct file_lock *new, struct file_lock *fl)
 434 {
 435         new->fl_u.nfs_fl.state = fl->fl_u.nfs_fl.state;
 436         new->fl_u.nfs_fl.owner = nlm_get_lockowner(fl->fl_u.nfs_fl.owner);
 437         list_add_tail(&new->fl_u.nfs_fl.list, &fl->fl_u.nfs_fl.owner->host->h_granted);
 438 }
 439
 440 static void nlmclnt_locks_release_private(struct file_lock *fl)
 441 {
 442         list_del(&fl->fl_u.nfs_fl.list);
 443         nlm_put_lockowner(fl->fl_u.nfs_fl.owner);
 444 }
 445
 446 static struct file_lock_operations nlmclnt_lock_ops = {
 447         .fl_copy_lock = nlmclnt_locks_copy_lock,
 448         .fl_release_private = nlmclnt_locks_release_private,
 449 };
 450
 451 static void nlmclnt_locks_init_private(struct file_lock *fl, struct nlm_host *host)
 452 {
 453         BUG_ON(fl->fl_ops != NULL);
 454         fl->fl_u.nfs_fl.state = 0;
 455         fl->fl_u.nfs_fl.owner = nlm_find_lockowner(host, fl->fl_owner);
 456         INIT_LIST_HEAD(&fl->fl_u.nfs_fl.list);
 457         fl->fl_ops = &nlmclnt_lock_ops;
 458 }
 459
 460 static void do_vfs_lock(struct file_lock *fl)
 461 {
 462         int res = 0;
 463         switch (fl->fl_flags & (FL_POSIX|FL_FLOCK)) {
 464                 case FL_POSIX:
 465                         res = posix_lock_file_wait(fl->fl_file, fl);
 466                         break;
 467                 case FL_FLOCK:
 468                         res = flock_lock_file_wait(fl->fl_file, fl);
 469                         break;
 470                 default:
 471                         BUG();
 472         }
 473         if (res < 0)
 474                 printk(KERN_WARNING "%s: VFS is out of sync with lock manager!\n",
 475                                 __FUNCTION__);
 476 }
 477
 478 /*
 479  * LOCK: Try to create a lock
 480  *
 481  *                      Programmer Harassment Alert
 482  *
 483  * When given a blocking lock request in a sync RPC call, the HPUX lockd
 484  * will faithfully return LCK_BLOCKED but never cares to notify us when
 485  * the lock could be granted. This way, our local process could hang
 486  * around forever waiting for the callback.
 487  *
 488  *  Solution A: Implement busy-waiting
 489  *  Solution B: Use the async version of the call (NLM_LOCK_{MSG,RES})
 490  *
 491  * For now I am implementing solution A, because I hate the idea of
 492  * re-implementing lockd for a third time in two months. The async
 493  * calls shouldn't be too hard to do, however.
 494  *
 495  * This is one of the lovely things about standards in the NFS area:
 496  * they're so soft and squishy you can't really blame HP for doing this.
 497  */
 498 static int
 499 nlmclnt_lock(struct nlm_rqst *req, struct file_lock *fl)
 500 {
 501         struct nlm_host *host = req->a_host;
 502         struct nlm_res  *resp = &req->a_res;
 503         struct nlm_wait *block = NULL;
 504         int status = -ENOLCK;
 505
 506         if (!host->h_monitored && nsm_monitor(host) < 0) {
 507                 printk(KERN_NOTICE "lockd: failed to monitor %s\n",
 508                                         host->h_name);
 509                 goto out;
 510         }
 511
 512         block = nlmclnt_prepare_block(host, fl);
 513         for(;;) {
 514                 status = nlmclnt_call(req, NLMPROC_LOCK);
 515                 if (status < 0)
 516                         goto out_unblock;
 517                 if (!req->a_args.block)
 518                         break;
 519                 /* Did a reclaimer thread notify us of a server reboot? */
 520                 if (resp->status ==  NLM_LCK_DENIED_GRACE_PERIOD)
 521                         continue;
 522                 if (resp->status != NLM_LCK_BLOCKED)
 523                         break;
 524                 /* Wait on an NLM blocking lock */
 525                 status = nlmclnt_block(block, req, NLMCLNT_POLL_TIMEOUT);
 526                 /* if we were interrupted. Send a CANCEL request to the server
 527                  * and exit
 528                  */
 529                 if (status < 0)
 530                         goto out_unblock;
 531                 if (resp->status != NLM_LCK_BLOCKED)
 532                         break;
 533         }
 534
 535         if (resp->status == NLM_LCK_GRANTED) {
 536                 fl->fl_u.nfs_fl.state = host->h_state;
 537                 fl->fl_flags |= FL_SLEEP;
 538                 /* Ensure the resulting lock will get added to granted list */
 539                 do_vfs_lock(fl);
 540         }
 541         status = nlm_stat_to_errno(resp->status);
 542 out_unblock:
 543         nlmclnt_finish_block(block);
 544         /* Cancel the blocked request if it is still pending */
 545         if (resp->status == NLM_LCK_BLOCKED)
 546                 nlmclnt_cancel(host, req->a_args.block, fl);
 547 out:
 548         nlm_release_call(req);
 549         return status;
 550 }
 551
 552 /*
 553  * RECLAIM: Try to reclaim a lock
 554  */
 555 int
 556 nlmclnt_reclaim(struct nlm_host *host, struct file_lock *fl)
 557 {
 558         struct nlm_rqst reqst, *req;
 559         int             status;
 560
 561         req = &reqst;
 562         memset(req, 0, sizeof(*req));
 563         locks_init_lock(&req->a_args.lock.fl);
 564         locks_init_lock(&req->a_res.lock.fl);
 565         req->a_host  = host;
 566         req->a_flags = 0;
 567
 568         /* Set up the argument struct */
 569         nlmclnt_setlockargs(req, fl);
 570         req->a_args.reclaim = 1;
 571
 572         if ((status = nlmclnt_call(req, NLMPROC_LOCK)) >= 0
 573          && req->a_res.status == NLM_LCK_GRANTED)
 574                 return 0;
 575
 576         printk(KERN_WARNING "lockd: failed to reclaim lock for pid %d "
 577                                 "(errno %d, status %d)\n", fl->fl_pid,
 578                                 status, req->a_res.status);
 579
 580         /*
 581          * FIXME: This is a serious failure. We can
 582          *
 583          *  a.  Ignore the problem
 584          *  b.  Send the owning process some signal (Linux doesn't have
 585          *      SIGLOST, though...)
 586          *  c.  Retry the operation
 587          *
 588          * Until someone comes up with a simple implementation
 589          * for b or c, I'll choose option a.
 590          */
 591
 592         return -ENOLCK;
 593 }
 594
 595 /*
 596  * UNLOCK: remove an existing lock
 597  */
 598 static int
 599 nlmclnt_unlock(struct nlm_rqst *req, struct file_lock *fl)
 600 {
 601         struct nlm_res  *resp = &req->a_res;
 602         int             status;
 603
 604         /*
 605          * Note: the server is supposed to either grant us the unlock
 606          * request, or to deny it with NLM_LCK_DENIED_GRACE_PERIOD. In either
 607          * case, we want to unlock.
 608          */
 609         do_vfs_lock(fl);
 610
 611         if (req->a_flags & RPC_TASK_ASYNC)
 612                 return nlm_async_call(req, NLMPROC_UNLOCK, &nlmclnt_unlock_ops);
 613
 614         status = nlmclnt_call(req, NLMPROC_UNLOCK);
 615         if (status < 0)
 616                 goto out;
 617
 618         status = 0;
 619         if (resp->status == NLM_LCK_GRANTED)
 620                 goto out;
 621
 622         if (resp->status != NLM_LCK_DENIED_NOLOCKS)
 623                 printk("lockd: unexpected unlock status: %d\n", resp->status);
 624         /* What to do now? I'm out of my depth... */
 625         status = -ENOLCK;
 626 out:
 627         nlm_release_call(req);
 628         return status;
 629 }
 630
 631 static void nlmclnt_unlock_callback(struct rpc_task *task, void *data)
 632 {
 633         struct nlm_rqst *req = data;
 634         int             status = req->a_res.status;
 635
 636         if (RPC_ASSASSINATED(task))
 637                 goto die;
 638
 639         if (task->tk_status < 0) {
 640                 dprintk("lockd: unlock failed (err = %d)\n", -task->tk_status);
 641                 goto retry_rebind;
 642         }
 643         if (status == NLM_LCK_DENIED_GRACE_PERIOD) {
 644                 rpc_delay(task, NLMCLNT_GRACE_WAIT);
 645                 goto retry_unlock;
 646         }
 647         if (status != NLM_LCK_GRANTED)
 648                 printk(KERN_WARNING "lockd: unexpected unlock status: %d\n", status);
 649 die:
 650         return;
 651  retry_rebind:
 652         nlm_rebind_host(req->a_host);
 653  retry_unlock:
 654         rpc_restart_call(task);
 655 }
 656
 657 static const struct rpc_call_ops nlmclnt_unlock_ops = {
 658         .rpc_call_done = nlmclnt_unlock_callback,
 659         .rpc_release = nlmclnt_rpc_release,
 660 };
 661
 662 /*
 663  * Cancel a blocked lock request.
 664  * We always use an async RPC call for this in order not to hang a
 665  * process that has been Ctrl-C'ed.
 666  */
 667 static int nlmclnt_cancel(struct nlm_host *host, int block, struct file_lock *fl)
 668 {
 669         struct nlm_rqst *req;
 670         unsigned long   flags;
 671         sigset_t        oldset;
 672         int             status;
 673
 674         /* Block all signals while setting up call */
 675         spin_lock_irqsave(&current->sighand->siglock, flags);
 676         oldset = current->blocked;
 677         sigfillset(&current->blocked);
 678         recalc_sigpending();
 679         spin_unlock_irqrestore(&current->sighand->siglock, flags);
 680
 681         req = nlm_alloc_call(nlm_get_host(host));
 682         if (!req)
 683                 return -ENOMEM;
 684         req->a_flags = RPC_TASK_ASYNC;
 685
 686         nlmclnt_setlockargs(req, fl);
 687         req->a_args.block = block;
 688
 689         status = nlm_async_call(req, NLMPROC_CANCEL, &nlmclnt_cancel_ops);
 690
 691         spin_lock_irqsave(&current->sighand->siglock, flags);
 692         current->blocked = oldset;
 693         recalc_sigpending();
 694         spin_unlock_irqrestore(&current->sighand->siglock, flags);
 695
 696         return status;
 697 }
 698
 699 static void nlmclnt_cancel_callback(struct rpc_task *task, void *data)
 700 {
 701         struct nlm_rqst *req = data;
 702
 703         if (RPC_ASSASSINATED(task))
 704                 goto die;
 705
 706         if (task->tk_status < 0) {
 707                 dprintk("lockd: CANCEL call error %d, retrying.\n",
 708                                         task->tk_status);
 709                 goto retry_cancel;
 710         }
 711
 712         dprintk("lockd: cancel status %d (task %d)\n",
 713                         req->a_res.status, task->tk_pid);
 714
 715         switch (req->a_res.status) {
 716         case NLM_LCK_GRANTED:
 717         case NLM_LCK_DENIED_GRACE_PERIOD:
 718         case NLM_LCK_DENIED:
 719                 /* Everything's good */
 720                 break;
 721         case NLM_LCK_DENIED_NOLOCKS:
 722                 dprintk("lockd: CANCEL failed (server has no locks)\n");
 723                 goto retry_cancel;
 724         default:
 725                 printk(KERN_NOTICE "lockd: weird return %d for CANCEL call\n",
 726                         req->a_res.status);
 727         }
 728
 729 die:
 730         return;
 731
 732 retry_cancel:
 733         /* Don't ever retry more than 3 times */
 734         if (req->a_retries++ >= NLMCLNT_MAX_RETRIES)
 735                 goto die;
 736         nlm_rebind_host(req->a_host);
 737         rpc_restart_call(task);
 738         rpc_delay(task, 30 * HZ);
 739 }
 740
 741 static const struct rpc_call_ops nlmclnt_cancel_ops = {
 742         .rpc_call_done = nlmclnt_cancel_callback,
 743         .rpc_release = nlmclnt_rpc_release,
 744 };
 745
 746 /*
 747  * Convert an NLM status code to a generic kernel errno
 748  */
 749 static int
 750 nlm_stat_to_errno(u32 status)
 751 {
 752         switch(status) {
 753         case NLM_LCK_GRANTED:
 754                 return 0;
 755         case NLM_LCK_DENIED:
 756                 return -EAGAIN;
 757         case NLM_LCK_DENIED_NOLOCKS:
 758         case NLM_LCK_DENIED_GRACE_PERIOD:
 759                 return -ENOLCK;
 760         case NLM_LCK_BLOCKED:
 761                 printk(KERN_NOTICE "lockd: unexpected status NLM_BLOCKED\n");
 762                 return -ENOLCK;
 763 #ifdef CONFIG_LOCKD_V4
 764         case NLM_DEADLCK:
 765                 return -EDEADLK;
 766         case NLM_ROFS:
 767                 return -EROFS;
 768         case NLM_STALE_FH:
 769                 return -ESTALE;
 770         case NLM_FBIG:
 771                 return -EOVERFLOW;
 772         case NLM_FAILED:
 773                 return -ENOLCK;
 774 #endif
 775         }
 776         printk(KERN_NOTICE "lockd: unexpected server status %d\n", status);
 777         return -ENOLCK;
 778 }