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   1 /*
   2  * linux/fs/lockd/clntproc.c
   3  *
   4  * RPC procedures for the client side NLM implementation
   5  *
   6  * Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de>
   7  */
   8
   9 #include <linux/config.h>
  10 #include <linux/module.h>
  11 #include <linux/types.h>
  12 #include <linux/errno.h>
  13 #include <linux/fs.h>
  14 #include <linux/nfs_fs.h>
  15 #include <linux/utsname.h>
  16 #include <linux/smp_lock.h>
  17 #include <linux/sunrpc/clnt.h>
  18 #include <linux/sunrpc/svc.h>
  19 #include <linux/lockd/lockd.h>
  20 #include <linux/lockd/sm_inter.h>
  21
  22 #define NLMDBG_FACILITY         NLMDBG_CLIENT
  23 #define NLMCLNT_GRACE_WAIT      (5*HZ)
  24 #define NLMCLNT_POLL_TIMEOUT    (30*HZ)
  25 #define NLMCLNT_MAX_RETRIES     3
  26
  27 static int      nlmclnt_test(struct nlm_rqst *, struct file_lock *);
  28 static int      nlmclnt_lock(struct nlm_rqst *, struct file_lock *);
  29 static int      nlmclnt_unlock(struct nlm_rqst *, struct file_lock *);
  30 static int      nlm_stat_to_errno(u32 stat);
  31 static void     nlmclnt_locks_init_private(struct file_lock *fl, struct nlm_host *host);
  32 static int      nlmclnt_cancel(struct nlm_host *, int , struct file_lock *);
  33
  34 static const struct rpc_call_ops nlmclnt_unlock_ops;
  35 static const struct rpc_call_ops nlmclnt_cancel_ops;
  36
  37 /*
  38  * Cookie counter for NLM requests
  39  */
  40 static u32      nlm_cookie = 0x1234;
  41
  42 static inline void nlmclnt_next_cookie(struct nlm_cookie *c)
  43 {
  44         memcpy(c->data, &nlm_cookie, 4);
  45         memset(c->data+4, 0, 4);
  46         c->len=4;
  47         nlm_cookie++;
  48 }
  49
  50 static struct nlm_lockowner *nlm_get_lockowner(struct nlm_lockowner *lockowner)
  51 {
  52         atomic_inc(&lockowner->count);
  53         return lockowner;
  54 }
  55
  56 static void nlm_put_lockowner(struct nlm_lockowner *lockowner)
  57 {
  58         if (!atomic_dec_and_lock(&lockowner->count, &lockowner->host->h_lock))
  59                 return;
  60         list_del(&lockowner->list);
  61         spin_unlock(&lockowner->host->h_lock);
  62         nlm_release_host(lockowner->host);
  63         kfree(lockowner);
  64 }
  65
  66 static inline int nlm_pidbusy(struct nlm_host *host, uint32_t pid)
  67 {
  68         struct nlm_lockowner *lockowner;
  69         list_for_each_entry(lockowner, &host->h_lockowners, list) {
  70                 if (lockowner->pid == pid)
  71                         return -EBUSY;
  72         }
  73         return 0;
  74 }
  75
  76 static inline uint32_t __nlm_alloc_pid(struct nlm_host *host)
  77 {
  78         uint32_t res;
  79         do {
  80                 res = host->h_pidcount++;
  81         } while (nlm_pidbusy(host, res) < 0);
  82         return res;
  83 }
  84
  85 static struct nlm_lockowner *__nlm_find_lockowner(struct nlm_host *host, fl_owner_t owner)
  86 {
  87         struct nlm_lockowner *lockowner;
  88         list_for_each_entry(lockowner, &host->h_lockowners, list) {
  89                 if (lockowner->owner != owner)
  90                         continue;
  91                 return nlm_get_lockowner(lockowner);
  92         }
  93         return NULL;
  94 }
  95
  96 static struct nlm_lockowner *nlm_find_lockowner(struct nlm_host *host, fl_owner_t owner)
  97 {
  98         struct nlm_lockowner *res, *new = NULL;
  99
 100         spin_lock(&host->h_lock);
 101         res = __nlm_find_lockowner(host, owner);
 102         if (res == NULL) {
 103                 spin_unlock(&host->h_lock);
 104                 new = (struct nlm_lockowner *)kmalloc(sizeof(*new), GFP_KERNEL);
 105                 spin_lock(&host->h_lock);
 106                 res = __nlm_find_lockowner(host, owner);
 107                 if (res == NULL && new != NULL) {
 108                         res = new;
 109                         atomic_set(&new->count, 1);
 110                         new->owner = owner;
 111                         new->pid = __nlm_alloc_pid(host);
 112                         new->host = nlm_get_host(host);
 113                         list_add(&new->list, &host->h_lockowners);
 114                         new = NULL;
 115                 }
 116         }
 117         spin_unlock(&host->h_lock);
 118         kfree(new);
 119         return res;
 120 }
 121
 122 /*
 123  * Initialize arguments for TEST/LOCK/UNLOCK/CANCEL calls
 124  */
 125 static void nlmclnt_setlockargs(struct nlm_rqst *req, struct file_lock *fl)
 126 {
 127         struct nlm_args *argp = &req->a_args;
 128         struct nlm_lock *lock = &argp->lock;
 129
 130         nlmclnt_next_cookie(&argp->cookie);
 131         argp->state   = nsm_local_state;
 132         memcpy(&lock->fh, NFS_FH(fl->fl_file->f_dentry->d_inode), sizeof(struct nfs_fh));
 133         lock->caller  = system_utsname.nodename;
 134         lock->oh.data = req->a_owner;
 135         lock->oh.len  = snprintf(req->a_owner, sizeof(req->a_owner), "%u@%s",
 136                                 (unsigned int)fl->fl_u.nfs_fl.owner->pid,
 137                                 system_utsname.nodename);
 138         lock->svid = fl->fl_u.nfs_fl.owner->pid;
 139         lock->fl.fl_start = fl->fl_start;
 140         lock->fl.fl_end = fl->fl_end;
 141         lock->fl.fl_type = fl->fl_type;
 142 }
 143
 144 static void nlmclnt_release_lockargs(struct nlm_rqst *req)
 145 {
 146         BUG_ON(req->a_args.lock.fl.fl_ops != NULL);
 147 }
 148
 149 /*
 150  * This is the main entry point for the NLM client.
 151  */
 152 int
 153 nlmclnt_proc(struct inode *inode, int cmd, struct file_lock *fl)
 154 {
 155         struct nlm_host         *host;
 156         struct nlm_rqst         *call;
 157         sigset_t                oldset;
 158         unsigned long           flags;
 159         int                     status, proto, vers;
 160
 161         vers = (NFS_PROTO(inode)->version == 3) ? 4 : 1;
 162         if (NFS_PROTO(inode)->version > 3) {
 163                 printk(KERN_NOTICE "NFSv4 file locking not implemented!\n");
 164                 return -ENOLCK;
 165         }
 166
 167         /* Retrieve transport protocol from NFS client */
 168         proto = NFS_CLIENT(inode)->cl_xprt->prot;
 169
 170         host = nlmclnt_lookup_host(NFS_ADDR(inode), proto, vers);
 171         if (host == NULL)
 172                 return -ENOLCK;
 173
 174         call = nlm_alloc_call(host);
 175         if (call == NULL)
 176                 return -ENOMEM;
 177
 178         nlmclnt_locks_init_private(fl, host);
 179         /* Set up the argument struct */
 180         nlmclnt_setlockargs(call, fl);
 181
 182         /* Keep the old signal mask */
 183         spin_lock_irqsave(&current->sighand->siglock, flags);
 184         oldset = current->blocked;
 185
 186         /* If we're cleaning up locks because the process is exiting,
 187          * perform the RPC call asynchronously. */
 188         if ((IS_SETLK(cmd) || IS_SETLKW(cmd))
 189             && fl->fl_type == F_UNLCK
 190             && (current->flags & PF_EXITING)) {
 191                 sigfillset(&current->blocked);  /* Mask all signals */
 192                 recalc_sigpending();
 193
 194                 call->a_flags = RPC_TASK_ASYNC;
 195         }
 196         spin_unlock_irqrestore(&current->sighand->siglock, flags);
 197
 198         if (IS_SETLK(cmd) || IS_SETLKW(cmd)) {
 199                 if (fl->fl_type != F_UNLCK) {
 200                         call->a_args.block = IS_SETLKW(cmd) ? 1 : 0;
 201                         status = nlmclnt_lock(call, fl);
 202                 } else
 203                         status = nlmclnt_unlock(call, fl);
 204         } else if (IS_GETLK(cmd))
 205                 status = nlmclnt_test(call, fl);
 206         else
 207                 status = -EINVAL;
 208
 209         fl->fl_ops->fl_release_private(fl);
 210         fl->fl_ops = NULL;
 211
 212         spin_lock_irqsave(&current->sighand->siglock, flags);
 213         current->blocked = oldset;
 214         recalc_sigpending();
 215         spin_unlock_irqrestore(&current->sighand->siglock, flags);
 216
 217         dprintk("lockd: clnt proc returns %d\n", status);
 218         return status;
 219 }
 220 EXPORT_SYMBOL(nlmclnt_proc);
 221
 222 /*
 223  * Allocate an NLM RPC call struct
 224  *
 225  * Note: the caller must hold a reference to host. In case of failure,
 226  * this reference will be released.
 227  */
 228 struct nlm_rqst *nlm_alloc_call(struct nlm_host *host)
 229 {
 230         struct nlm_rqst *call;
 231
 232         for(;;) {
 233                 call = kzalloc(sizeof(*call), GFP_KERNEL);
 234                 if (call != NULL) {
 235                         locks_init_lock(&call->a_args.lock.fl);
 236                         locks_init_lock(&call->a_res.lock.fl);
 237                         call->a_host = host;
 238                         return call;
 239                 }
 240                 if (signalled())
 241                         break;
 242                 printk("nlm_alloc_call: failed, waiting for memory\n");
 243                 schedule_timeout_interruptible(5*HZ);
 244         }
 245         nlm_release_host(host);
 246         return NULL;
 247 }
 248
 249 void nlm_release_call(struct nlm_rqst *call)
 250 {
 251         nlm_release_host(call->a_host);
 252         nlmclnt_release_lockargs(call);
 253         kfree(call);
 254 }
 255
 256 static void nlmclnt_rpc_release(void *data)
 257 {
 258         return nlm_release_call(data);
 259 }
 260
 261 static int nlm_wait_on_grace(wait_queue_head_t *queue)
 262 {
 263         DEFINE_WAIT(wait);
 264         int status = -EINTR;
 265
 266         prepare_to_wait(queue, &wait, TASK_INTERRUPTIBLE);
 267         if (!signalled ()) {
 268                 schedule_timeout(NLMCLNT_GRACE_WAIT);
 269                 try_to_freeze();
 270                 if (!signalled ())
 271                         status = 0;
 272         }
 273         finish_wait(queue, &wait);
 274         return status;
 275 }
 276
 277 /*
 278  * Generic NLM call
 279  */
 280 static int
 281 nlmclnt_call(struct nlm_rqst *req, u32 proc)
 282 {
 283         struct nlm_host *host = req->a_host;
 284         struct rpc_clnt *clnt;
 285         struct nlm_args *argp = &req->a_args;
 286         struct nlm_res  *resp = &req->a_res;
 287         struct rpc_message msg = {
 288                 .rpc_argp       = argp,
 289                 .rpc_resp       = resp,
 290         };
 291         int             status;
 292
 293         dprintk("lockd: call procedure %d on %s\n",
 294                         (int)proc, host->h_name);
 295
 296         do {
 297                 if (host->h_reclaiming && !argp->reclaim)
 298                         goto in_grace_period;
 299
 300                 /* If we have no RPC client yet, create one. */
 301                 if ((clnt = nlm_bind_host(host)) == NULL)
 302                         return -ENOLCK;
 303                 msg.rpc_proc = &clnt->cl_procinfo[proc];
 304
 305                 /* Perform the RPC call. If an error occurs, try again */
 306                 if ((status = rpc_call_sync(clnt, &msg, 0)) < 0) {
 307                         dprintk("lockd: rpc_call returned error %d\n", -status);
 308                         switch (status) {
 309                         case -EPROTONOSUPPORT:
 310                                 status = -EINVAL;
 311                                 break;
 312                         case -ECONNREFUSED:
 313                         case -ETIMEDOUT:
 314                         case -ENOTCONN:
 315                                 nlm_rebind_host(host);
 316                                 status = -EAGAIN;
 317                                 break;
 318                         case -ERESTARTSYS:
 319                                 return signalled () ? -EINTR : status;
 320                         default:
 321                                 break;
 322                         }
 323                         break;
 324                 } else
 325                 if (resp->status == NLM_LCK_DENIED_GRACE_PERIOD) {
 326                         dprintk("lockd: server in grace period\n");
 327                         if (argp->reclaim) {
 328                                 printk(KERN_WARNING
 329                                      "lockd: spurious grace period reject?!\n");
 330                                 return -ENOLCK;
 331                         }
 332                 } else {
 333                         if (!argp->reclaim) {
 334                                 /* We appear to be out of the grace period */
 335                                 wake_up_all(&host->h_gracewait);
 336                         }
 337                         dprintk("lockd: server returns status %d\n", resp->status);
 338                         return 0;       /* Okay, call complete */
 339                 }
 340
 341 in_grace_period:
 342                 /*
 343                  * The server has rebooted and appears to be in the grace
 344                  * period during which locks are only allowed to be
 345                  * reclaimed.
 346                  * We can only back off and try again later.
 347                  */
 348                 status = nlm_wait_on_grace(&host->h_gracewait);
 349         } while (status == 0);
 350
 351         return status;
 352 }
 353
 354 /*
 355  * Generic NLM call, async version.
 356  */
 357 int nlm_async_call(struct nlm_rqst *req, u32 proc, const struct rpc_call_ops *tk_ops)
 358 {
 359         struct nlm_host *host = req->a_host;
 360         struct rpc_clnt *clnt;
 361         struct rpc_message msg = {
 362                 .rpc_argp       = &req->a_args,
 363                 .rpc_resp       = &req->a_res,
 364         };
 365         int status = -ENOLCK;
 366
 367         dprintk("lockd: call procedure %d on %s (async)\n",
 368                         (int)proc, host->h_name);
 369
 370         /* If we have no RPC client yet, create one. */
 371         clnt = nlm_bind_host(host);
 372         if (clnt == NULL)
 373                 goto out_err;
 374         msg.rpc_proc = &clnt->cl_procinfo[proc];
 375
 376         /* bootstrap and kick off the async RPC call */
 377         status = rpc_call_async(clnt, &msg, RPC_TASK_ASYNC, tk_ops, req);
 378         if (status == 0)
 379                 return 0;
 380 out_err:
 381         nlm_release_call(req);
 382         return status;
 383 }
 384
 385 /*
 386  * TEST for the presence of a conflicting lock
 387  */
 388 static int
 389 nlmclnt_test(struct nlm_rqst *req, struct file_lock *fl)
 390 {
 391         int     status;
 392
 393         status = nlmclnt_call(req, NLMPROC_TEST);
 394         if (status < 0)
 395                 goto out;
 396
 397         switch (req->a_res.status) {
 398                 case NLM_LCK_GRANTED:
 399                         fl->fl_type = F_UNLCK;
 400                         break;
 401                 case NLM_LCK_DENIED:
 402                         /*
 403                          * Report the conflicting lock back to the application.
 404                          */
 405                         fl->fl_start = req->a_res.lock.fl.fl_start;
 406                         fl->fl_end = req->a_res.lock.fl.fl_start;
 407                         fl->fl_type = req->a_res.lock.fl.fl_type;
 408                         fl->fl_pid = 0;
 409                         break;
 410                 default:
 411                         status = nlm_stat_to_errno(req->a_res.status);
 412         }
 413 out:
 414         nlm_release_call(req);
 415         return status;
 416 }
 417
 418 static void nlmclnt_locks_copy_lock(struct file_lock *new, struct file_lock *fl)
 419 {
 420         new->fl_u.nfs_fl.state = fl->fl_u.nfs_fl.state;
 421         new->fl_u.nfs_fl.owner = nlm_get_lockowner(fl->fl_u.nfs_fl.owner);
 422         list_add_tail(&new->fl_u.nfs_fl.list, &fl->fl_u.nfs_fl.owner->host->h_granted);
 423 }
 424
 425 static void nlmclnt_locks_release_private(struct file_lock *fl)
 426 {
 427         list_del(&fl->fl_u.nfs_fl.list);
 428         nlm_put_lockowner(fl->fl_u.nfs_fl.owner);
 429 }
 430
 431 static struct file_lock_operations nlmclnt_lock_ops = {
 432         .fl_copy_lock = nlmclnt_locks_copy_lock,
 433         .fl_release_private = nlmclnt_locks_release_private,
 434 };
 435
 436 static void nlmclnt_locks_init_private(struct file_lock *fl, struct nlm_host *host)
 437 {
 438         BUG_ON(fl->fl_ops != NULL);
 439         fl->fl_u.nfs_fl.state = 0;
 440         fl->fl_u.nfs_fl.owner = nlm_find_lockowner(host, fl->fl_owner);
 441         INIT_LIST_HEAD(&fl->fl_u.nfs_fl.list);
 442         fl->fl_ops = &nlmclnt_lock_ops;
 443 }
 444
 445 static void do_vfs_lock(struct file_lock *fl)
 446 {
 447         int res = 0;
 448         switch (fl->fl_flags & (FL_POSIX|FL_FLOCK)) {
 449                 case FL_POSIX:
 450                         res = posix_lock_file_wait(fl->fl_file, fl);
 451                         break;
 452                 case FL_FLOCK:
 453                         res = flock_lock_file_wait(fl->fl_file, fl);
 454                         break;
 455                 default:
 456                         BUG();
 457         }
 458         if (res < 0)
 459                 printk(KERN_WARNING "%s: VFS is out of sync with lock manager!\n",
 460                                 __FUNCTION__);
 461 }
 462
 463 /*
 464  * LOCK: Try to create a lock
 465  *
 466  *                      Programmer Harassment Alert
 467  *
 468  * When given a blocking lock request in a sync RPC call, the HPUX lockd
 469  * will faithfully return LCK_BLOCKED but never cares to notify us when
 470  * the lock could be granted. This way, our local process could hang
 471  * around forever waiting for the callback.
 472  *
 473  *  Solution A: Implement busy-waiting
 474  *  Solution B: Use the async version of the call (NLM_LOCK_{MSG,RES})
 475  *
 476  * For now I am implementing solution A, because I hate the idea of
 477  * re-implementing lockd for a third time in two months. The async
 478  * calls shouldn't be too hard to do, however.
 479  *
 480  * This is one of the lovely things about standards in the NFS area:
 481  * they're so soft and squishy you can't really blame HP for doing this.
 482  */
 483 static int
 484 nlmclnt_lock(struct nlm_rqst *req, struct file_lock *fl)
 485 {
 486         struct nlm_host *host = req->a_host;
 487         struct nlm_res  *resp = &req->a_res;
 488         struct nlm_wait *block = NULL;
 489         int status = -ENOLCK;
 490
 491         if (!host->h_monitored && nsm_monitor(host) < 0) {
 492                 printk(KERN_NOTICE "lockd: failed to monitor %s\n",
 493                                         host->h_name);
 494                 goto out;
 495         }
 496
 497         block = nlmclnt_prepare_block(host, fl);
 498         for(;;) {
 499                 status = nlmclnt_call(req, NLMPROC_LOCK);
 500                 if (status < 0)
 501                         goto out_unblock;
 502                 if (!req->a_args.block)
 503                         break;
 504                 /* Did a reclaimer thread notify us of a server reboot? */
 505                 if (resp->status ==  NLM_LCK_DENIED_GRACE_PERIOD)
 506                         continue;
 507                 if (resp->status != NLM_LCK_BLOCKED)
 508                         break;
 509                 /* Wait on an NLM blocking lock */
 510                 status = nlmclnt_block(block, req, NLMCLNT_POLL_TIMEOUT);
 511                 /* if we were interrupted. Send a CANCEL request to the server
 512                  * and exit
 513                  */
 514                 if (status < 0)
 515                         goto out_unblock;
 516                 if (resp->status != NLM_LCK_BLOCKED)
 517                         break;
 518         }
 519
 520         if (resp->status == NLM_LCK_GRANTED) {
 521                 fl->fl_u.nfs_fl.state = host->h_state;
 522                 fl->fl_flags |= FL_SLEEP;
 523                 /* Ensure the resulting lock will get added to granted list */
 524                 do_vfs_lock(fl);
 525         }
 526         status = nlm_stat_to_errno(resp->status);
 527 out_unblock:
 528         nlmclnt_finish_block(block);
 529         /* Cancel the blocked request if it is still pending */
 530         if (resp->status == NLM_LCK_BLOCKED)
 531                 nlmclnt_cancel(host, req->a_args.block, fl);
 532 out:
 533         nlm_release_call(req);
 534         return status;
 535 }
 536
 537 /*
 538  * RECLAIM: Try to reclaim a lock
 539  */
 540 int
 541 nlmclnt_reclaim(struct nlm_host *host, struct file_lock *fl)
 542 {
 543         struct nlm_rqst reqst, *req;
 544         int             status;
 545
 546         req = &reqst;
 547         memset(req, 0, sizeof(*req));
 548         locks_init_lock(&req->a_args.lock.fl);
 549         locks_init_lock(&req->a_res.lock.fl);
 550         req->a_host  = host;
 551         req->a_flags = 0;
 552
 553         /* Set up the argument struct */
 554         nlmclnt_setlockargs(req, fl);
 555         req->a_args.reclaim = 1;
 556
 557         if ((status = nlmclnt_call(req, NLMPROC_LOCK)) >= 0
 558          && req->a_res.status == NLM_LCK_GRANTED)
 559                 return 0;
 560
 561         printk(KERN_WARNING "lockd: failed to reclaim lock for pid %d "
 562                                 "(errno %d, status %d)\n", fl->fl_pid,
 563                                 status, req->a_res.status);
 564
 565         /*
 566          * FIXME: This is a serious failure. We can
 567          *
 568          *  a.  Ignore the problem
 569          *  b.  Send the owning process some signal (Linux doesn't have
 570          *      SIGLOST, though...)
 571          *  c.  Retry the operation
 572          *
 573          * Until someone comes up with a simple implementation
 574          * for b or c, I'll choose option a.
 575          */
 576
 577         return -ENOLCK;
 578 }
 579
 580 /*
 581  * UNLOCK: remove an existing lock
 582  */
 583 static int
 584 nlmclnt_unlock(struct nlm_rqst *req, struct file_lock *fl)
 585 {
 586         struct nlm_res  *resp = &req->a_res;
 587         int             status;
 588
 589         /*
 590          * Note: the server is supposed to either grant us the unlock
 591          * request, or to deny it with NLM_LCK_DENIED_GRACE_PERIOD. In either
 592          * case, we want to unlock.
 593          */
 594         do_vfs_lock(fl);
 595
 596         if (req->a_flags & RPC_TASK_ASYNC)
 597                 return nlm_async_call(req, NLMPROC_UNLOCK, &nlmclnt_unlock_ops);
 598
 599         status = nlmclnt_call(req, NLMPROC_UNLOCK);
 600         if (status < 0)
 601                 goto out;
 602
 603         status = 0;
 604         if (resp->status == NLM_LCK_GRANTED)
 605                 goto out;
 606
 607         if (resp->status != NLM_LCK_DENIED_NOLOCKS)
 608                 printk("lockd: unexpected unlock status: %d\n", resp->status);
 609         /* What to do now? I'm out of my depth... */
 610         status = -ENOLCK;
 611 out:
 612         nlm_release_call(req);
 613         return status;
 614 }
 615
 616 static void nlmclnt_unlock_callback(struct rpc_task *task, void *data)
 617 {
 618         struct nlm_rqst *req = data;
 619         int             status = req->a_res.status;
 620
 621         if (RPC_ASSASSINATED(task))
 622                 goto die;
 623
 624         if (task->tk_status < 0) {
 625                 dprintk("lockd: unlock failed (err = %d)\n", -task->tk_status);
 626                 goto retry_rebind;
 627         }
 628         if (status == NLM_LCK_DENIED_GRACE_PERIOD) {
 629                 rpc_delay(task, NLMCLNT_GRACE_WAIT);
 630                 goto retry_unlock;
 631         }
 632         if (status != NLM_LCK_GRANTED)
 633                 printk(KERN_WARNING "lockd: unexpected unlock status: %d\n", status);
 634 die:
 635         return;
 636  retry_rebind:
 637         nlm_rebind_host(req->a_host);
 638  retry_unlock:
 639         rpc_restart_call(task);
 640 }
 641
 642 static const struct rpc_call_ops nlmclnt_unlock_ops = {
 643         .rpc_call_done = nlmclnt_unlock_callback,
 644         .rpc_release = nlmclnt_rpc_release,
 645 };
 646
 647 /*
 648  * Cancel a blocked lock request.
 649  * We always use an async RPC call for this in order not to hang a
 650  * process that has been Ctrl-C'ed.
 651  */
 652 static int nlmclnt_cancel(struct nlm_host *host, int block, struct file_lock *fl)
 653 {
 654         struct nlm_rqst *req;
 655         unsigned long   flags;
 656         sigset_t        oldset;
 657         int             status;
 658
 659         /* Block all signals while setting up call */
 660         spin_lock_irqsave(&current->sighand->siglock, flags);
 661         oldset = current->blocked;
 662         sigfillset(&current->blocked);
 663         recalc_sigpending();
 664         spin_unlock_irqrestore(&current->sighand->siglock, flags);
 665
 666         req = nlm_alloc_call(nlm_get_host(host));
 667         if (!req)
 668                 return -ENOMEM;
 669         req->a_flags = RPC_TASK_ASYNC;
 670
 671         nlmclnt_setlockargs(req, fl);
 672         req->a_args.block = block;
 673
 674         status = nlm_async_call(req, NLMPROC_CANCEL, &nlmclnt_cancel_ops);
 675
 676         spin_lock_irqsave(&current->sighand->siglock, flags);
 677         current->blocked = oldset;
 678         recalc_sigpending();
 679         spin_unlock_irqrestore(&current->sighand->siglock, flags);
 680
 681         return status;
 682 }
 683
 684 static void nlmclnt_cancel_callback(struct rpc_task *task, void *data)
 685 {
 686         struct nlm_rqst *req = data;
 687
 688         if (RPC_ASSASSINATED(task))
 689                 goto die;
 690
 691         if (task->tk_status < 0) {
 692                 dprintk("lockd: CANCEL call error %d, retrying.\n",
 693                                         task->tk_status);
 694                 goto retry_cancel;
 695         }
 696
 697         dprintk("lockd: cancel status %d (task %d)\n",
 698                         req->a_res.status, task->tk_pid);
 699
 700         switch (req->a_res.status) {
 701         case NLM_LCK_GRANTED:
 702         case NLM_LCK_DENIED_GRACE_PERIOD:
 703         case NLM_LCK_DENIED:
 704                 /* Everything's good */
 705                 break;
 706         case NLM_LCK_DENIED_NOLOCKS:
 707                 dprintk("lockd: CANCEL failed (server has no locks)\n");
 708                 goto retry_cancel;
 709         default:
 710                 printk(KERN_NOTICE "lockd: weird return %d for CANCEL call\n",
 711                         req->a_res.status);
 712         }
 713
 714 die:
 715         return;
 716
 717 retry_cancel:
 718         /* Don't ever retry more than 3 times */
 719         if (req->a_retries++ >= NLMCLNT_MAX_RETRIES)
 720                 goto die;
 721         nlm_rebind_host(req->a_host);
 722         rpc_restart_call(task);
 723         rpc_delay(task, 30 * HZ);
 724 }
 725
 726 static const struct rpc_call_ops nlmclnt_cancel_ops = {
 727         .rpc_call_done = nlmclnt_cancel_callback,
 728         .rpc_release = nlmclnt_rpc_release,
 729 };
 730
 731 /*
 732  * Convert an NLM status code to a generic kernel errno
 733  */
 734 static int
 735 nlm_stat_to_errno(u32 status)
 736 {
 737         switch(status) {
 738         case NLM_LCK_GRANTED:
 739                 return 0;
 740         case NLM_LCK_DENIED:
 741                 return -EAGAIN;
 742         case NLM_LCK_DENIED_NOLOCKS:
 743         case NLM_LCK_DENIED_GRACE_PERIOD:
 744                 return -ENOLCK;
 745         case NLM_LCK_BLOCKED:
 746                 printk(KERN_NOTICE "lockd: unexpected status NLM_BLOCKED\n");
 747                 return -ENOLCK;
 748 #ifdef CONFIG_LOCKD_V4
 749         case NLM_DEADLCK:
 750                 return -EDEADLK;
 751         case NLM_ROFS:
 752                 return -EROFS;
 753         case NLM_STALE_FH:
 754                 return -ESTALE;
 755         case NLM_FBIG:
 756                 return -EOVERFLOW;
 757         case NLM_FAILED:
 758                 return -ENOLCK;
 759 #endif
 760         }
 761         printk(KERN_NOTICE "lockd: unexpected server status %d\n", status);
 762         return -ENOLCK;
 763 }