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/sunrpc/clnt.h>
  17 #include <linux/sunrpc/svc.h>
  18 #include <linux/lockd/lockd.h>
  19 #include <linux/lockd/sm_inter.h>
  20 #include <linux/vs_base.h>
  21 #include <linux/vs_cvirt.h>
  22
  23 #define NLMDBG_FACILITY         NLMDBG_CLIENT
  24 #define NLMCLNT_GRACE_WAIT      (5*HZ)
  25 #define NLMCLNT_POLL_TIMEOUT    (30*HZ)
  26 #define NLMCLNT_MAX_RETRIES     3
  27
  28 static int      nlmclnt_test(struct nlm_rqst *, struct file_lock *);
  29 static int      nlmclnt_lock(struct nlm_rqst *, struct file_lock *);
  30 static int      nlmclnt_unlock(struct nlm_rqst *, struct file_lock *);
  31 static int      nlm_stat_to_errno(u32 stat);
  32 static void     nlmclnt_locks_init_private(struct file_lock *fl, struct nlm_host *host);
  33 static int      nlmclnt_cancel(struct nlm_host *, int , struct file_lock *);
  34
  35 static const struct rpc_call_ops nlmclnt_unlock_ops;
  36 static const struct rpc_call_ops nlmclnt_cancel_ops;
  37
  38 /*
  39  * Cookie counter for NLM requests
  40  */
  41 static u32      nlm_cookie = 0x1234;
  42
  43 static inline void nlmclnt_next_cookie(struct nlm_cookie *c)
  44 {
  45         memcpy(c->data, &nlm_cookie, 4);
  46         memset(c->data+4, 0, 4);
  47         c->len=4;
  48         nlm_cookie++;
  49 }
  50
  51 static struct nlm_lockowner *nlm_get_lockowner(struct nlm_lockowner *lockowner)
  52 {
  53         atomic_inc(&lockowner->count);
  54         return lockowner;
  55 }
  56
  57 static void nlm_put_lockowner(struct nlm_lockowner *lockowner)
  58 {
  59         if (!atomic_dec_and_lock(&lockowner->count, &lockowner->host->h_lock))
  60                 return;
  61         list_del(&lockowner->list);
  62         spin_unlock(&lockowner->host->h_lock);
  63         nlm_release_host(lockowner->host);
  64         kfree(lockowner);
  65 }
  66
  67 static inline int nlm_pidbusy(struct nlm_host *host, uint32_t pid)
  68 {
  69         struct nlm_lockowner *lockowner;
  70         list_for_each_entry(lockowner, &host->h_lockowners, list) {
  71                 if (lockowner->pid == pid)
  72                         return -EBUSY;
  73         }
  74         return 0;
  75 }
  76
  77 static inline uint32_t __nlm_alloc_pid(struct nlm_host *host)
  78 {
  79         uint32_t res;
  80         do {
  81                 res = host->h_pidcount++;
  82         } while (nlm_pidbusy(host, res) < 0);
  83         return res;
  84 }
  85
  86 static struct nlm_lockowner *__nlm_find_lockowner(struct nlm_host *host, fl_owner_t owner)
  87 {
  88         struct nlm_lockowner *lockowner;
  89         list_for_each_entry(lockowner, &host->h_lockowners, list) {
  90                 if (lockowner->owner != owner)
  91                         continue;
  92                 return nlm_get_lockowner(lockowner);
  93         }
  94         return NULL;
  95 }
  96
  97 static struct nlm_lockowner *nlm_find_lockowner(struct nlm_host *host, fl_owner_t owner)
  98 {
  99         struct nlm_lockowner *res, *new = NULL;
 100
 101         spin_lock(&host->h_lock);
 102         res = __nlm_find_lockowner(host, owner);
 103         if (res == NULL) {
 104                 spin_unlock(&host->h_lock);
 105                 new = (struct nlm_lockowner *)kmalloc(sizeof(*new), GFP_KERNEL);
 106                 spin_lock(&host->h_lock);
 107                 res = __nlm_find_lockowner(host, owner);
 108                 if (res == NULL && new != NULL) {
 109                         res = new;
 110                         atomic_set(&new->count, 1);
 111                         new->owner = owner;
 112                         new->pid = __nlm_alloc_pid(host);
 113                         new->host = nlm_get_host(host);
 114                         list_add(&new->list, &host->h_lockowners);
 115                         new = NULL;
 116                 }
 117         }
 118         spin_unlock(&host->h_lock);
 119         kfree(new);
 120         return res;
 121 }
 122
 123 /*
 124  * Initialize arguments for TEST/LOCK/UNLOCK/CANCEL calls
 125  */
 126 static void nlmclnt_setlockargs(struct nlm_rqst *req, struct file_lock *fl)
 127 {
 128         struct nlm_args *argp = &req->a_args;
 129         struct nlm_lock *lock = &argp->lock;
 130
 131         nlmclnt_next_cookie(&argp->cookie);
 132         argp->state   = nsm_local_state;
 133         memcpy(&lock->fh, NFS_FH(fl->fl_file->f_dentry->d_inode), sizeof(struct nfs_fh));
 134         lock->caller  = vx_new_uts(nodename);
 135         lock->oh.data = req->a_owner;
 136         lock->oh.len  = snprintf(req->a_owner, sizeof(req->a_owner), "%u@%s",
 137                                 (unsigned int)fl->fl_u.nfs_fl.owner->pid,
 138                                 vx_new_uts(nodename));
 139         lock->svid = fl->fl_u.nfs_fl.owner->pid;
 140         lock->fl.fl_start = fl->fl_start;
 141         lock->fl.fl_end = fl->fl_end;
 142         lock->fl.fl_type = fl->fl_type;
 143 }
 144
 145 static void nlmclnt_release_lockargs(struct nlm_rqst *req)
 146 {
 147         BUG_ON(req->a_args.lock.fl.fl_ops != NULL);
 148 }
 149
 150 /*
 151  * This is the main entry point for the NLM client.
 152  */
 153 int
 154 nlmclnt_proc(struct inode *inode, int cmd, struct file_lock *fl)
 155 {
 156         struct nlm_host         *host;
 157         struct nlm_rqst         *call;
 158         sigset_t                oldset;
 159         unsigned long           flags;
 160         int                     status, proto, vers;
 161
 162         vers = (NFS_PROTO(inode)->version == 3) ? 4 : 1;
 163         if (NFS_PROTO(inode)->version > 3) {
 164                 printk(KERN_NOTICE "NFSv4 file locking not implemented!\n");
 165                 return -ENOLCK;
 166         }
 167
 168         /* Retrieve transport protocol from NFS client */
 169         proto = NFS_CLIENT(inode)->cl_xprt->prot;
 170
 171         host = nlmclnt_lookup_host(NFS_ADDR(inode), proto, vers);
 172         if (host == NULL)
 173                 return -ENOLCK;
 174
 175         call = nlm_alloc_call(host);
 176         if (call == NULL)
 177                 return -ENOMEM;
 178
 179         nlmclnt_locks_init_private(fl, host);
 180         /* Set up the argument struct */
 181         nlmclnt_setlockargs(call, fl);
 182
 183         /* Keep the old signal mask */
 184         spin_lock_irqsave(&current->sighand->siglock, flags);
 185         oldset = current->blocked;
 186
 187         /* If we're cleaning up locks because the process is exiting,
 188          * perform the RPC call asynchronously. */
 189         if ((IS_SETLK(cmd) || IS_SETLKW(cmd))
 190             && fl->fl_type == F_UNLCK
 191             && (current->flags & PF_EXITING)) {
 192                 sigfillset(&current->blocked);  /* Mask all signals */
 193                 recalc_sigpending();
 194
 195                 call->a_flags = RPC_TASK_ASYNC;
 196         }
 197         spin_unlock_irqrestore(&current->sighand->siglock, flags);
 198
 199         if (IS_SETLK(cmd) || IS_SETLKW(cmd)) {
 200                 if (fl->fl_type != F_UNLCK) {
 201                         call->a_args.block = IS_SETLKW(cmd) ? 1 : 0;
 202                         status = nlmclnt_lock(call, fl);
 203                 } else
 204                         status = nlmclnt_unlock(call, fl);
 205         } else if (IS_GETLK(cmd))
 206                 status = nlmclnt_test(call, fl);
 207         else
 208                 status = -EINVAL;
 209
 210         fl->fl_ops->fl_release_private(fl);
 211         fl->fl_ops = NULL;
 212
 213         spin_lock_irqsave(&current->sighand->siglock, flags);
 214         current->blocked = oldset;
 215         recalc_sigpending();
 216         spin_unlock_irqrestore(&current->sighand->siglock, flags);
 217
 218         dprintk("lockd: clnt proc returns %d\n", status);
 219         return status;
 220 }
 221 EXPORT_SYMBOL(nlmclnt_proc);
 222
 223 /*
 224  * Allocate an NLM RPC call struct
 225  *
 226  * Note: the caller must hold a reference to host. In case of failure,
 227  * this reference will be released.
 228  */
 229 struct nlm_rqst *nlm_alloc_call(struct nlm_host *host)
 230 {
 231         struct nlm_rqst *call;
 232
 233         for(;;) {
 234                 call = kzalloc(sizeof(*call), GFP_KERNEL);
 235                 if (call != NULL) {
 236                         locks_init_lock(&call->a_args.lock.fl);
 237                         locks_init_lock(&call->a_res.lock.fl);
 238                         call->a_host = host;
 239                         return call;
 240                 }
 241                 if (signalled())
 242                         break;
 243                 printk("nlm_alloc_call: failed, waiting for memory\n");
 244                 schedule_timeout_interruptible(5*HZ);
 245         }
 246         nlm_release_host(host);
 247         return NULL;
 248 }
 249
 250 void nlm_release_call(struct nlm_rqst *call)
 251 {
 252         nlm_release_host(call->a_host);
 253         nlmclnt_release_lockargs(call);
 254         kfree(call);
 255 }
 256
 257 static void nlmclnt_rpc_release(void *data)
 258 {
 259         return nlm_release_call(data);
 260 }
 261
 262 static int nlm_wait_on_grace(wait_queue_head_t *queue)
 263 {
 264         DEFINE_WAIT(wait);
 265         int status = -EINTR;
 266
 267         prepare_to_wait(queue, &wait, TASK_INTERRUPTIBLE);
 268         if (!signalled ()) {
 269                 schedule_timeout(NLMCLNT_GRACE_WAIT);
 270                 try_to_freeze();
 271                 if (!signalled ())
 272                         status = 0;
 273         }
 274         finish_wait(queue, &wait);
 275         return status;
 276 }
 277
 278 /*
 279  * Generic NLM call
 280  */
 281 static int
 282 nlmclnt_call(struct nlm_rqst *req, u32 proc)
 283 {
 284         struct nlm_host *host = req->a_host;
 285         struct rpc_clnt *clnt;
 286         struct nlm_args *argp = &req->a_args;
 287         struct nlm_res  *resp = &req->a_res;
 288         struct rpc_message msg = {
 289                 .rpc_argp       = argp,
 290                 .rpc_resp       = resp,
 291         };
 292         int             status;
 293
 294         dprintk("lockd: call procedure %d on %s\n",
 295                         (int)proc, host->h_name);
 296
 297         do {
 298                 if (host->h_reclaiming && !argp->reclaim)
 299                         goto in_grace_period;
 300
 301                 /* If we have no RPC client yet, create one. */
 302                 if ((clnt = nlm_bind_host(host)) == NULL)
 303                         return -ENOLCK;
 304                 msg.rpc_proc = &clnt->cl_procinfo[proc];
 305
 306                 /* Perform the RPC call. If an error occurs, try again */
 307                 if ((status = rpc_call_sync(clnt, &msg, 0)) < 0) {
 308                         dprintk("lockd: rpc_call returned error %d\n", -status);
 309                         switch (status) {
 310                         case -EPROTONOSUPPORT:
 311                                 status = -EINVAL;
 312                                 break;
 313                         case -ECONNREFUSED:
 314                         case -ETIMEDOUT:
 315                         case -ENOTCONN:
 316                                 nlm_rebind_host(host);
 317                                 status = -EAGAIN;
 318                                 break;
 319                         case -ERESTARTSYS:
 320                                 return signalled () ? -EINTR : status;
 321                         default:
 322                                 break;
 323                         }
 324                         break;
 325                 } else
 326                 if (resp->status == NLM_LCK_DENIED_GRACE_PERIOD) {
 327                         dprintk("lockd: server in grace period\n");
 328                         if (argp->reclaim) {
 329                                 printk(KERN_WARNING
 330                                      "lockd: spurious grace period reject?!\n");
 331                                 return -ENOLCK;
 332                         }
 333                 } else {
 334                         if (!argp->reclaim) {
 335                                 /* We appear to be out of the grace period */
 336                                 wake_up_all(&host->h_gracewait);
 337                         }
 338                         dprintk("lockd: server returns status %d\n", resp->status);
 339                         return 0;       /* Okay, call complete */
 340                 }
 341
 342 in_grace_period:
 343                 /*
 344                  * The server has rebooted and appears to be in the grace
 345                  * period during which locks are only allowed to be
 346                  * reclaimed.
 347                  * We can only back off and try again later.
 348                  */
 349                 status = nlm_wait_on_grace(&host->h_gracewait);
 350         } while (status == 0);
 351
 352         return status;
 353 }
 354
 355 /*
 356  * Generic NLM call, async version.
 357  */
 358 static int __nlm_async_call(struct nlm_rqst *req, u32 proc, struct rpc_message *msg, const struct rpc_call_ops *tk_ops)
 359 {
 360         struct nlm_host *host = req->a_host;
 361         struct rpc_clnt *clnt;
 362         int status = -ENOLCK;
 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         status = rpc_call_async(clnt, msg, RPC_TASK_ASYNC, tk_ops, req);
 375         if (status == 0)
 376                 return 0;
 377 out_err:
 378         nlm_release_call(req);
 379         return status;
 380 }
 381
 382 int nlm_async_call(struct nlm_rqst *req, u32 proc, const struct rpc_call_ops *tk_ops)
 383 {
 384         struct rpc_message msg = {
 385                 .rpc_argp       = &req->a_args,
 386                 .rpc_resp       = &req->a_res,
 387         };
 388         return __nlm_async_call(req, proc, &msg, tk_ops);
 389 }
 390
 391 int nlm_async_reply(struct nlm_rqst *req, u32 proc, const struct rpc_call_ops *tk_ops)
 392 {
 393         struct rpc_message msg = {
 394                 .rpc_argp       = &req->a_res,
 395         };
 396         return __nlm_async_call(req, proc, &msg, tk_ops);
 397 }
 398
 399 /*
 400  * TEST for the presence of a conflicting lock
 401  */
 402 static int
 403 nlmclnt_test(struct nlm_rqst *req, struct file_lock *fl)
 404 {
 405         int     status;
 406
 407         status = nlmclnt_call(req, NLMPROC_TEST);
 408         if (status < 0)
 409                 goto out;
 410
 411         switch (req->a_res.status) {
 412                 case NLM_LCK_GRANTED:
 413                         fl->fl_type = F_UNLCK;
 414                         break;
 415                 case NLM_LCK_DENIED:
 416                         /*
 417                          * Report the conflicting lock back to the application.
 418                          */
 419                         fl->fl_start = req->a_res.lock.fl.fl_start;
 420                         fl->fl_end = req->a_res.lock.fl.fl_start;
 421                         fl->fl_type = req->a_res.lock.fl.fl_type;
 422                         fl->fl_pid = 0;
 423                         break;
 424                 default:
 425                         status = nlm_stat_to_errno(req->a_res.status);
 426         }
 427 out:
 428         nlm_release_call(req);
 429         return status;
 430 }
 431
 432 static void nlmclnt_locks_copy_lock(struct file_lock *new, struct file_lock *fl)
 433 {
 434         new->fl_u.nfs_fl.state = fl->fl_u.nfs_fl.state;
 435         new->fl_u.nfs_fl.owner = nlm_get_lockowner(fl->fl_u.nfs_fl.owner);
 436         list_add_tail(&new->fl_u.nfs_fl.list, &fl->fl_u.nfs_fl.owner->host->h_granted);
 437 }
 438
 439 static void nlmclnt_locks_release_private(struct file_lock *fl)
 440 {
 441         list_del(&fl->fl_u.nfs_fl.list);
 442         nlm_put_lockowner(fl->fl_u.nfs_fl.owner);
 443 }
 444
 445 static struct file_lock_operations nlmclnt_lock_ops = {
 446         .fl_copy_lock = nlmclnt_locks_copy_lock,
 447         .fl_release_private = nlmclnt_locks_release_private,
 448 };
 449
 450 static void nlmclnt_locks_init_private(struct file_lock *fl, struct nlm_host *host)
 451 {
 452         BUG_ON(fl->fl_ops != NULL);
 453         fl->fl_u.nfs_fl.state = 0;
 454         fl->fl_u.nfs_fl.owner = nlm_find_lockowner(host, fl->fl_owner);
 455         INIT_LIST_HEAD(&fl->fl_u.nfs_fl.list);
 456         fl->fl_ops = &nlmclnt_lock_ops;
 457 }
 458
 459 static int do_vfs_lock(struct file_lock *fl)
 460 {
 461         int res = 0;
 462         switch (fl->fl_flags & (FL_POSIX|FL_FLOCK)) {
 463                 case FL_POSIX:
 464                         res = posix_lock_file_wait(fl->fl_file, fl);
 465                         break;
 466                 case FL_FLOCK:
 467                         res = flock_lock_file_wait(fl->fl_file, fl);
 468                         break;
 469                 default:
 470                         BUG();
 471         }
 472         return res;
 473 }
 474
 475 /*
 476  * LOCK: Try to create a lock
 477  *
 478  *                      Programmer Harassment Alert
 479  *
 480  * When given a blocking lock request in a sync RPC call, the HPUX lockd
 481  * will faithfully return LCK_BLOCKED but never cares to notify us when
 482  * the lock could be granted. This way, our local process could hang
 483  * around forever waiting for the callback.
 484  *
 485  *  Solution A: Implement busy-waiting
 486  *  Solution B: Use the async version of the call (NLM_LOCK_{MSG,RES})
 487  *
 488  * For now I am implementing solution A, because I hate the idea of
 489  * re-implementing lockd for a third time in two months. The async
 490  * calls shouldn't be too hard to do, however.
 491  *
 492  * This is one of the lovely things about standards in the NFS area:
 493  * they're so soft and squishy you can't really blame HP for doing this.
 494  */
 495 static int
 496 nlmclnt_lock(struct nlm_rqst *req, struct file_lock *fl)
 497 {
 498         struct nlm_host *host = req->a_host;
 499         struct nlm_res  *resp = &req->a_res;
 500         struct nlm_wait *block = NULL;
 501         unsigned char fl_flags = fl->fl_flags;
 502         int status = -ENOLCK;
 503
 504         if (!host->h_monitored && nsm_monitor(host) < 0) {
 505                 printk(KERN_NOTICE "lockd: failed to monitor %s\n",
 506                                         host->h_name);
 507                 goto out;
 508         }
 509         fl->fl_flags |= FL_ACCESS;
 510         status = do_vfs_lock(fl);
 511         if (status < 0)
 512                 goto out;
 513
 514         block = nlmclnt_prepare_block(host, fl);
 515 again:
 516         for(;;) {
 517                 /* Reboot protection */
 518                 fl->fl_u.nfs_fl.state = host->h_state;
 519                 status = nlmclnt_call(req, NLMPROC_LOCK);
 520                 if (status < 0)
 521                         goto out_unblock;
 522                 if (!req->a_args.block)
 523                         break;
 524                 /* Did a reclaimer thread notify us of a server reboot? */
 525                 if (resp->status ==  NLM_LCK_DENIED_GRACE_PERIOD)
 526                         continue;
 527                 if (resp->status != NLM_LCK_BLOCKED)
 528                         break;
 529                 /* Wait on an NLM blocking lock */
 530                 status = nlmclnt_block(block, req, NLMCLNT_POLL_TIMEOUT);
 531                 /* if we were interrupted. Send a CANCEL request to the server
 532                  * and exit
 533                  */
 534                 if (status < 0)
 535                         goto out_unblock;
 536                 if (resp->status != NLM_LCK_BLOCKED)
 537                         break;
 538         }
 539
 540         if (resp->status == NLM_LCK_GRANTED) {
 541                 down_read(&host->h_rwsem);
 542                 /* Check whether or not the server has rebooted */
 543                 if (fl->fl_u.nfs_fl.state != host->h_state) {
 544                         up_read(&host->h_rwsem);
 545                         goto again;
 546                 }
 547                 /* Ensure the resulting lock will get added to granted list */
 548                 fl->fl_flags = fl_flags | FL_SLEEP;
 549                 if (do_vfs_lock(fl) < 0)
 550                         printk(KERN_WARNING "%s: VFS is out of sync with lock manager!\n", __FUNCTION__);
 551                 up_read(&host->h_rwsem);
 552         }
 553         status = nlm_stat_to_errno(resp->status);
 554 out_unblock:
 555         nlmclnt_finish_block(block);
 556         /* Cancel the blocked request if it is still pending */
 557         if (resp->status == NLM_LCK_BLOCKED)
 558                 nlmclnt_cancel(host, req->a_args.block, fl);
 559 out:
 560         nlm_release_call(req);
 561         fl->fl_flags = fl_flags;
 562         return status;
 563 }
 564
 565 /*
 566  * RECLAIM: Try to reclaim a lock
 567  */
 568 int
 569 nlmclnt_reclaim(struct nlm_host *host, struct file_lock *fl)
 570 {
 571         struct nlm_rqst reqst, *req;
 572         int             status;
 573
 574         req = &reqst;
 575         memset(req, 0, sizeof(*req));
 576         locks_init_lock(&req->a_args.lock.fl);
 577         locks_init_lock(&req->a_res.lock.fl);
 578         req->a_host  = host;
 579         req->a_flags = 0;
 580
 581         /* Set up the argument struct */
 582         nlmclnt_setlockargs(req, fl);
 583         req->a_args.reclaim = 1;
 584
 585         if ((status = nlmclnt_call(req, NLMPROC_LOCK)) >= 0
 586          && req->a_res.status == NLM_LCK_GRANTED)
 587                 return 0;
 588
 589         printk(KERN_WARNING "lockd: failed to reclaim lock for pid %d "
 590                                 "(errno %d, status %d)\n", fl->fl_pid,
 591                                 status, req->a_res.status);
 592
 593         /*
 594          * FIXME: This is a serious failure. We can
 595          *
 596          *  a.  Ignore the problem
 597          *  b.  Send the owning process some signal (Linux doesn't have
 598          *      SIGLOST, though...)
 599          *  c.  Retry the operation
 600          *
 601          * Until someone comes up with a simple implementation
 602          * for b or c, I'll choose option a.
 603          */
 604
 605         return -ENOLCK;
 606 }
 607
 608 /*
 609  * UNLOCK: remove an existing lock
 610  */
 611 static int
 612 nlmclnt_unlock(struct nlm_rqst *req, struct file_lock *fl)
 613 {
 614         struct nlm_host *host = req->a_host;
 615         struct nlm_res  *resp = &req->a_res;
 616         int status = 0;
 617
 618         /*
 619          * Note: the server is supposed to either grant us the unlock
 620          * request, or to deny it with NLM_LCK_DENIED_GRACE_PERIOD. In either
 621          * case, we want to unlock.
 622          */
 623         fl->fl_flags |= FL_EXISTS;
 624         down_read(&host->h_rwsem);
 625         if (do_vfs_lock(fl) == -ENOENT) {
 626                 up_read(&host->h_rwsem);
 627                 goto out;
 628         }
 629         up_read(&host->h_rwsem);
 630
 631         if (req->a_flags & RPC_TASK_ASYNC)
 632                 return nlm_async_call(req, NLMPROC_UNLOCK, &nlmclnt_unlock_ops);
 633
 634         status = nlmclnt_call(req, NLMPROC_UNLOCK);
 635         if (status < 0)
 636                 goto out;
 637
 638         if (resp->status == NLM_LCK_GRANTED)
 639                 goto out;
 640
 641         if (resp->status != NLM_LCK_DENIED_NOLOCKS)
 642                 printk("lockd: unexpected unlock status: %d\n", resp->status);
 643         /* What to do now? I'm out of my depth... */
 644         status = -ENOLCK;
 645 out:
 646         nlm_release_call(req);
 647         return status;
 648 }
 649
 650 static void nlmclnt_unlock_callback(struct rpc_task *task, void *data)
 651 {
 652         struct nlm_rqst *req = data;
 653         int             status = req->a_res.status;
 654
 655         if (RPC_ASSASSINATED(task))
 656                 goto die;
 657
 658         if (task->tk_status < 0) {
 659                 dprintk("lockd: unlock failed (err = %d)\n", -task->tk_status);
 660                 goto retry_rebind;
 661         }
 662         if (status == NLM_LCK_DENIED_GRACE_PERIOD) {
 663                 rpc_delay(task, NLMCLNT_GRACE_WAIT);
 664                 goto retry_unlock;
 665         }
 666         if (status != NLM_LCK_GRANTED)
 667                 printk(KERN_WARNING "lockd: unexpected unlock status: %d\n", status);
 668 die:
 669         return;
 670  retry_rebind:
 671         nlm_rebind_host(req->a_host);
 672  retry_unlock:
 673         rpc_restart_call(task);
 674 }
 675
 676 static const struct rpc_call_ops nlmclnt_unlock_ops = {
 677         .rpc_call_done = nlmclnt_unlock_callback,
 678         .rpc_release = nlmclnt_rpc_release,
 679 };
 680
 681 /*
 682  * Cancel a blocked lock request.
 683  * We always use an async RPC call for this in order not to hang a
 684  * process that has been Ctrl-C'ed.
 685  */
 686 static int nlmclnt_cancel(struct nlm_host *host, int block, struct file_lock *fl)
 687 {
 688         struct nlm_rqst *req;
 689         unsigned long   flags;
 690         sigset_t        oldset;
 691         int             status;
 692
 693         /* Block all signals while setting up call */
 694         spin_lock_irqsave(&current->sighand->siglock, flags);
 695         oldset = current->blocked;
 696         sigfillset(&current->blocked);
 697         recalc_sigpending();
 698         spin_unlock_irqrestore(&current->sighand->siglock, flags);
 699
 700         req = nlm_alloc_call(nlm_get_host(host));
 701         if (!req)
 702                 return -ENOMEM;
 703         req->a_flags = RPC_TASK_ASYNC;
 704
 705         nlmclnt_setlockargs(req, fl);
 706         req->a_args.block = block;
 707
 708         status = nlm_async_call(req, NLMPROC_CANCEL, &nlmclnt_cancel_ops);
 709
 710         spin_lock_irqsave(&current->sighand->siglock, flags);
 711         current->blocked = oldset;
 712         recalc_sigpending();
 713         spin_unlock_irqrestore(&current->sighand->siglock, flags);
 714
 715         return status;
 716 }
 717
 718 static void nlmclnt_cancel_callback(struct rpc_task *task, void *data)
 719 {
 720         struct nlm_rqst *req = data;
 721
 722         if (RPC_ASSASSINATED(task))
 723                 goto die;
 724
 725         if (task->tk_status < 0) {
 726                 dprintk("lockd: CANCEL call error %d, retrying.\n",
 727                                         task->tk_status);
 728                 goto retry_cancel;
 729         }
 730
 731         dprintk("lockd: cancel status %d (task %d)\n",
 732                         req->a_res.status, task->tk_pid);
 733
 734         switch (req->a_res.status) {
 735         case NLM_LCK_GRANTED:
 736         case NLM_LCK_DENIED_GRACE_PERIOD:
 737         case NLM_LCK_DENIED:
 738                 /* Everything's good */
 739                 break;
 740         case NLM_LCK_DENIED_NOLOCKS:
 741                 dprintk("lockd: CANCEL failed (server has no locks)\n");
 742                 goto retry_cancel;
 743         default:
 744                 printk(KERN_NOTICE "lockd: weird return %d for CANCEL call\n",
 745                         req->a_res.status);
 746         }
 747
 748 die:
 749         return;
 750
 751 retry_cancel:
 752         /* Don't ever retry more than 3 times */
 753         if (req->a_retries++ >= NLMCLNT_MAX_RETRIES)
 754                 goto die;
 755         nlm_rebind_host(req->a_host);
 756         rpc_restart_call(task);
 757         rpc_delay(task, 30 * HZ);
 758 }
 759
 760 static const struct rpc_call_ops nlmclnt_cancel_ops = {
 761         .rpc_call_done = nlmclnt_cancel_callback,
 762         .rpc_release = nlmclnt_rpc_release,
 763 };
 764
 765 /*
 766  * Convert an NLM status code to a generic kernel errno
 767  */
 768 static int
 769 nlm_stat_to_errno(u32 status)
 770 {
 771         switch(status) {
 772         case NLM_LCK_GRANTED:
 773                 return 0;
 774         case NLM_LCK_DENIED:
 775                 return -EAGAIN;
 776         case NLM_LCK_DENIED_NOLOCKS:
 777         case NLM_LCK_DENIED_GRACE_PERIOD:
 778                 return -ENOLCK;
 779         case NLM_LCK_BLOCKED:
 780                 printk(KERN_NOTICE "lockd: unexpected status NLM_BLOCKED\n");
 781                 return -ENOLCK;
 782 #ifdef CONFIG_LOCKD_V4
 783         case NLM_DEADLCK:
 784                 return -EDEADLK;
 785         case NLM_ROFS:
 786                 return -EROFS;
 787         case NLM_STALE_FH:
 788                 return -ESTALE;
 789         case NLM_FBIG:
 790                 return -EOVERFLOW;
 791         case NLM_FAILED:
 792                 return -ENOLCK;
 793 #endif
 794         }
 795         printk(KERN_NOTICE "lockd: unexpected server status %d\n", status);
 796         return -ENOLCK;
 797 }