fs/lockd/clntproc.c

   1 /*
   2  * linux/fs/lockd/clntproc.c
   3  *
   4  * RPC procedures for the client side NLM implementation
   5  *
   6  * Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de>
   7  */
   8
   9 #include <linux/module.h>
  10 #include <linux/types.h>
  11 #include <linux/errno.h>
  12 #include <linux/fs.h>
  13 #include <linux/nfs_fs.h>
  14 #include <linux/utsname.h>
  15 #include <linux/freezer.h>
  16 #include <linux/sunrpc/clnt.h>
  17 #include <linux/sunrpc/svc.h>
  18 #include <linux/lockd/lockd.h>
  19 #include <linux/lockd/sm_inter.h>
  20
  21 #define NLMDBG_FACILITY         NLMDBG_CLIENT
  22 #define NLMCLNT_GRACE_WAIT      (5*HZ)
  23 #define NLMCLNT_POLL_TIMEOUT    (30*HZ)
  24 #define NLMCLNT_MAX_RETRIES     3
  25
  26 static int      nlmclnt_test(struct nlm_rqst *, struct file_lock *);
  27 static int      nlmclnt_lock(struct nlm_rqst *, struct file_lock *);
  28 static int      nlmclnt_unlock(struct nlm_rqst *, struct file_lock *);
  29 static int      nlm_stat_to_errno(__be32 stat);
  30 static void     nlmclnt_locks_init_private(struct file_lock *fl, struct nlm_host *host);
  31 static int      nlmclnt_cancel(struct nlm_host *, int , struct file_lock *);
  32
  33 static const struct rpc_call_ops nlmclnt_unlock_ops;
  34 static const struct rpc_call_ops nlmclnt_cancel_ops;
  35
  36 /*
  37  * Cookie counter for NLM requests
  38  */
  39 static atomic_t nlm_cookie = ATOMIC_INIT(0x1234);
  40
  41 void nlmclnt_next_cookie(struct nlm_cookie *c)
  42 {
  43         u32     cookie = atomic_inc_return(&nlm_cookie);
  44
  45         memcpy(c->data, &cookie, 4);
  46         c->len=4;
  47 }
  48
  49 static struct nlm_lockowner *nlm_get_lockowner(struct nlm_lockowner *lockowner)
  50 {
  51         atomic_inc(&lockowner->count);
  52         return lockowner;
  53 }
  54
  55 static void nlm_put_lockowner(struct nlm_lockowner *lockowner)
  56 {
  57         if (!atomic_dec_and_lock(&lockowner->count, &lockowner->host->h_lock))
  58                 return;
  59         list_del(&lockowner->list);
  60         spin_unlock(&lockowner->host->h_lock);
  61         nlm_release_host(lockowner->host);
  62         kfree(lockowner);
  63 }
  64
  65 static inline int nlm_pidbusy(struct nlm_host *host, uint32_t pid)
  66 {
  67         struct nlm_lockowner *lockowner;
  68         list_for_each_entry(lockowner, &host->h_lockowners, list) {
  69                 if (lockowner->pid == pid)
  70                         return -EBUSY;
  71         }
  72         return 0;
  73 }
  74
  75 static inline uint32_t __nlm_alloc_pid(struct nlm_host *host)
  76 {
  77         uint32_t res;
  78         do {
  79                 res = host->h_pidcount++;
  80         } while (nlm_pidbusy(host, res) < 0);
  81         return res;
  82 }
  83
  84 static struct nlm_lockowner *__nlm_find_lockowner(struct nlm_host *host, fl_owner_t owner)
  85 {
  86         struct nlm_lockowner *lockowner;
  87         list_for_each_entry(lockowner, &host->h_lockowners, list) {
  88                 if (lockowner->owner != owner)
  89                         continue;
  90                 return nlm_get_lockowner(lockowner);
  91         }
  92         return NULL;
  93 }
  94
  95 static struct nlm_lockowner *nlm_find_lockowner(struct nlm_host *host, fl_owner_t owner)
  96 {
  97         struct nlm_lockowner *res, *new = NULL;
  98
  99         spin_lock(&host->h_lock);
 100         res = __nlm_find_lockowner(host, owner);
 101         if (res == NULL) {
 102                 spin_unlock(&host->h_lock);
 103                 new = kmalloc(sizeof(*new), GFP_KERNEL);
 104                 spin_lock(&host->h_lock);
 105                 res = __nlm_find_lockowner(host, owner);
 106                 if (res == NULL && new != NULL) {
 107                         res = new;
 108                         atomic_set(&new->count, 1);
 109                         new->owner = owner;
 110                         new->pid = __nlm_alloc_pid(host);
 111                         new->host = nlm_get_host(host);
 112                         list_add(&new->list, &host->h_lockowners);
 113                         new = NULL;
 114                 }
 115         }
 116         spin_unlock(&host->h_lock);
 117         kfree(new);
 118         return res;
 119 }
 120
 121 /*
 122  * Initialize arguments for TEST/LOCK/UNLOCK/CANCEL calls
 123  */
 124 static void nlmclnt_setlockargs(struct nlm_rqst *req, struct file_lock *fl)
 125 {
 126         struct nlm_args *argp = &req->a_args;
 127         struct nlm_lock *lock = &argp->lock;
 128
 129         nlmclnt_next_cookie(&argp->cookie);
 130         argp->state   = nsm_local_state;
 131         memcpy(&lock->fh, NFS_FH(fl->fl_file->f_path.dentry->d_inode), sizeof(struct nfs_fh));
 132         lock->caller  = utsname()->nodename;
 133         lock->oh.data = req->a_owner;
 134         lock->oh.len  = snprintf(req->a_owner, sizeof(req->a_owner), "%u@%s",
 135                                 (unsigned int)fl->fl_u.nfs_fl.owner->pid,
 136                                 utsname()->nodename);
 137         lock->svid = fl->fl_u.nfs_fl.owner->pid;
 138         lock->fl.fl_start = fl->fl_start;
 139         lock->fl.fl_end = fl->fl_end;
 140         lock->fl.fl_type = fl->fl_type;
 141 }
 142
 143 static void nlmclnt_release_lockargs(struct nlm_rqst *req)
 144 {
 145         BUG_ON(req->a_args.lock.fl.fl_ops != NULL);
 146 }
 147
 148 /**
 149  * nlmclnt_proc - Perform a single client-side lock request
 150  * @host: address of a valid nlm_host context representing the NLM server
 151  * @cmd: fcntl-style file lock operation to perform
 152  * @fl: address of arguments for the lock operation
 153  *
 154  */
 155 int nlmclnt_proc(struct nlm_host *host, int cmd, struct file_lock *fl)
 156 {
 157         struct nlm_rqst         *call;
 158         sigset_t                oldset;
 159         unsigned long           flags;
 160         int                     status;
 161
 162         nlm_get_host(host);
 163         call = nlm_alloc_call(host);
 164         if (call == NULL)
 165                 return -ENOMEM;
 166
 167         nlmclnt_locks_init_private(fl, host);
 168         /* Set up the argument struct */
 169         nlmclnt_setlockargs(call, fl);
 170
 171         /* Keep the old signal mask */
 172         spin_lock_irqsave(&current->sighand->siglock, flags);
 173         oldset = current->blocked;
 174
 175         /* If we're cleaning up locks because the process is exiting,
 176          * perform the RPC call asynchronously. */
 177         if ((IS_SETLK(cmd) || IS_SETLKW(cmd))
 178             && fl->fl_type == F_UNLCK
 179             && (current->flags & PF_EXITING)) {
 180                 sigfillset(&current->blocked);  /* Mask all signals */
 181                 recalc_sigpending();
 182
 183                 call->a_flags = RPC_TASK_ASYNC;
 184         }
 185         spin_unlock_irqrestore(&current->sighand->siglock, flags);
 186
 187         if (IS_SETLK(cmd) || IS_SETLKW(cmd)) {
 188                 if (fl->fl_type != F_UNLCK) {
 189                         call->a_args.block = IS_SETLKW(cmd) ? 1 : 0;
 190                         status = nlmclnt_lock(call, fl);
 191                 } else
 192                         status = nlmclnt_unlock(call, fl);
 193         } else if (IS_GETLK(cmd))
 194                 status = nlmclnt_test(call, fl);
 195         else
 196                 status = -EINVAL;
 197
 198         fl->fl_ops->fl_release_private(fl);
 199         fl->fl_ops = NULL;
 200
 201         spin_lock_irqsave(&current->sighand->siglock, flags);
 202         current->blocked = oldset;
 203         recalc_sigpending();
 204         spin_unlock_irqrestore(&current->sighand->siglock, flags);
 205
 206         dprintk("lockd: clnt proc returns %d\n", status);
 207         return status;
 208 }
 209 EXPORT_SYMBOL_GPL(nlmclnt_proc);
 210
 211 /*
 212  * Allocate an NLM RPC call struct
 213  *
 214  * Note: the caller must hold a reference to host. In case of failure,
 215  * this reference will be released.
 216  */
 217 struct nlm_rqst *nlm_alloc_call(struct nlm_host *host)
 218 {
 219         struct nlm_rqst *call;
 220
 221         for(;;) {
 222                 call = kzalloc(sizeof(*call), GFP_KERNEL);
 223                 if (call != NULL) {
 224                         atomic_set(&call->a_count, 1);
 225                         locks_init_lock(&call->a_args.lock.fl);
 226                         locks_init_lock(&call->a_res.lock.fl);
 227                         call->a_host = host;
 228                         return call;
 229                 }
 230                 if (signalled())
 231                         break;
 232                 printk("nlm_alloc_call: failed, waiting for memory\n");
 233                 schedule_timeout_interruptible(5*HZ);
 234         }
 235         nlm_release_host(host);
 236         return NULL;
 237 }
 238
 239 void nlm_release_call(struct nlm_rqst *call)
 240 {
 241         if (!atomic_dec_and_test(&call->a_count))
 242                 return;
 243         nlm_release_host(call->a_host);
 244         nlmclnt_release_lockargs(call);
 245         kfree(call);
 246 }
 247
 248 static void nlmclnt_rpc_release(void *data)
 249 {
 250         nlm_release_call(data);
 251 }
 252
 253 static int nlm_wait_on_grace(wait_queue_head_t *queue)
 254 {
 255         DEFINE_WAIT(wait);
 256         int status = -EINTR;
 257
 258         prepare_to_wait(queue, &wait, TASK_INTERRUPTIBLE);
 259         if (!signalled ()) {
 260                 schedule_timeout(NLMCLNT_GRACE_WAIT);
 261                 try_to_freeze();
 262                 if (!signalled ())
 263                         status = 0;
 264         }
 265         finish_wait(queue, &wait);
 266         return status;
 267 }
 268
 269 /*
 270  * Generic NLM call
 271  */
 272 static int
 273 nlmclnt_call(struct nlm_rqst *req, u32 proc)
 274 {
 275         struct nlm_host *host = req->a_host;
 276         struct rpc_clnt *clnt;
 277         struct nlm_args *argp = &req->a_args;
 278         struct nlm_res  *resp = &req->a_res;
 279         struct rpc_message msg = {
 280                 .rpc_argp       = argp,
 281                 .rpc_resp       = resp,
 282         };
 283         int             status;
 284
 285         dprintk("lockd: call procedure %d on %s\n",
 286                         (int)proc, host->h_name);
 287
 288         do {
 289                 if (host->h_reclaiming && !argp->reclaim)
 290                         goto in_grace_period;
 291
 292                 /* If we have no RPC client yet, create one. */
 293                 if ((clnt = nlm_bind_host(host)) == NULL)
 294                         return -ENOLCK;
 295                 msg.rpc_proc = &clnt->cl_procinfo[proc];
 296
 297                 /* Perform the RPC call. If an error occurs, try again */
 298                 if ((status = rpc_call_sync(clnt, &msg, 0)) < 0) {
 299                         dprintk("lockd: rpc_call returned error %d\n", -status);
 300                         switch (status) {
 301                         case -EPROTONOSUPPORT:
 302                                 status = -EINVAL;
 303                                 break;
 304                         case -ECONNREFUSED:
 305                         case -ETIMEDOUT:
 306                         case -ENOTCONN:
 307                                 nlm_rebind_host(host);
 308                                 status = -EAGAIN;
 309                                 break;
 310                         case -ERESTARTSYS:
 311                                 return signalled () ? -EINTR : status;
 312                         default:
 313                                 break;
 314                         }
 315                         break;
 316                 } else
 317                 if (resp->status == nlm_lck_denied_grace_period) {
 318                         dprintk("lockd: server in grace period\n");
 319                         if (argp->reclaim) {
 320                                 printk(KERN_WARNING
 321                                      "lockd: spurious grace period reject?!\n");
 322                                 return -ENOLCK;
 323                         }
 324                 } else {
 325                         if (!argp->reclaim) {
 326                                 /* We appear to be out of the grace period */
 327                                 wake_up_all(&host->h_gracewait);
 328                         }
 329                         dprintk("lockd: server returns status %d\n", resp->status);
 330                         return 0;       /* Okay, call complete */
 331                 }
 332
 333 in_grace_period:
 334                 /*
 335                  * The server has rebooted and appears to be in the grace
 336                  * period during which locks are only allowed to be
 337                  * reclaimed.
 338                  * We can only back off and try again later.
 339                  */
 340                 status = nlm_wait_on_grace(&host->h_gracewait);
 341         } while (status == 0);
 342
 343         return status;
 344 }
 345
 346 /*
 347  * Generic NLM call, async version.
 348  */
 349 static int __nlm_async_call(struct nlm_rqst *req, u32 proc, struct rpc_message *msg, const struct rpc_call_ops *tk_ops)
 350 {
 351         struct nlm_host *host = req->a_host;
 352         struct rpc_clnt *clnt;
 353
 354         dprintk("lockd: call procedure %d on %s (async)\n",
 355                         (int)proc, host->h_name);
 356
 357         /* If we have no RPC client yet, create one. */
 358         clnt = nlm_bind_host(host);
 359         if (clnt == NULL)
 360                 goto out_err;
 361         msg->rpc_proc = &clnt->cl_procinfo[proc];
 362
 363         /* bootstrap and kick off the async RPC call */
 364         return rpc_call_async(clnt, msg, RPC_TASK_ASYNC, tk_ops, req);
 365 out_err:
 366         tk_ops->rpc_release(req);
 367         return -ENOLCK;
 368 }
 369
 370 int nlm_async_call(struct nlm_rqst *req, u32 proc, const struct rpc_call_ops *tk_ops)
 371 {
 372         struct rpc_message msg = {
 373                 .rpc_argp       = &req->a_args,
 374                 .rpc_resp       = &req->a_res,
 375         };
 376         return __nlm_async_call(req, proc, &msg, tk_ops);
 377 }
 378
 379 int nlm_async_reply(struct nlm_rqst *req, u32 proc, const struct rpc_call_ops *tk_ops)
 380 {
 381         struct rpc_message msg = {
 382                 .rpc_argp       = &req->a_res,
 383         };
 384         return __nlm_async_call(req, proc, &msg, tk_ops);
 385 }
 386
 387 /*
 388  * TEST for the presence of a conflicting lock
 389  */
 390 static int
 391 nlmclnt_test(struct nlm_rqst *req, struct file_lock *fl)
 392 {
 393         int     status;
 394
 395         status = nlmclnt_call(req, NLMPROC_TEST);
 396         if (status < 0)
 397                 goto out;
 398
 399         switch (req->a_res.status) {
 400                 case nlm_granted:
 401                         fl->fl_type = F_UNLCK;
 402                         break;
 403                 case nlm_lck_denied:
 404                         /*
 405                          * Report the conflicting lock back to the application.
 406                          */
 407                         fl->fl_start = req->a_res.lock.fl.fl_start;
 408                         fl->fl_end = req->a_res.lock.fl.fl_start;
 409                         fl->fl_type = req->a_res.lock.fl.fl_type;
 410                         fl->fl_pid = 0;
 411                         break;
 412                 default:
 413                         status = nlm_stat_to_errno(req->a_res.status);
 414         }
 415 out:
 416         nlm_release_call(req);
 417         return status;
 418 }
 419
 420 static void nlmclnt_locks_copy_lock(struct file_lock *new, struct file_lock *fl)
 421 {
 422         new->fl_u.nfs_fl.state = fl->fl_u.nfs_fl.state;
 423         new->fl_u.nfs_fl.owner = nlm_get_lockowner(fl->fl_u.nfs_fl.owner);
 424         list_add_tail(&new->fl_u.nfs_fl.list, &fl->fl_u.nfs_fl.owner->host->h_granted);
 425 }
 426
 427 static void nlmclnt_locks_release_private(struct file_lock *fl)
 428 {
 429         list_del(&fl->fl_u.nfs_fl.list);
 430         nlm_put_lockowner(fl->fl_u.nfs_fl.owner);
 431 }
 432
 433 static struct file_lock_operations nlmclnt_lock_ops = {
 434         .fl_copy_lock = nlmclnt_locks_copy_lock,
 435         .fl_release_private = nlmclnt_locks_release_private,
 436 };
 437
 438 static void nlmclnt_locks_init_private(struct file_lock *fl, struct nlm_host *host)
 439 {
 440         BUG_ON(fl->fl_ops != NULL);
 441         fl->fl_u.nfs_fl.state = 0;
 442         fl->fl_u.nfs_fl.owner = nlm_find_lockowner(host, fl->fl_owner);
 443         INIT_LIST_HEAD(&fl->fl_u.nfs_fl.list);
 444         fl->fl_ops = &nlmclnt_lock_ops;
 445 }
 446
 447 static int do_vfs_lock(struct file_lock *fl)
 448 {
 449         int res = 0;
 450         switch (fl->fl_flags & (FL_POSIX|FL_FLOCK)) {
 451                 case FL_POSIX:
 452                         res = posix_lock_file_wait(fl->fl_file, fl);
 453                         break;
 454                 case FL_FLOCK:
 455                         res = flock_lock_file_wait(fl->fl_file, fl);
 456                         break;
 457                 default:
 458                         BUG();
 459         }
 460         return res;
 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         unsigned char fl_flags = fl->fl_flags;
 490         int status = -ENOLCK;
 491
 492         if (nsm_monitor(host) < 0) {
 493                 printk(KERN_NOTICE "lockd: failed to monitor %s\n",
 494                                         host->h_name);
 495                 goto out;
 496         }
 497         fl->fl_flags |= FL_ACCESS;
 498         status = do_vfs_lock(fl);
 499         fl->fl_flags = fl_flags;
 500         if (status < 0)
 501                 goto out;
 502
 503         block = nlmclnt_prepare_block(host, fl);
 504 again:
 505         for(;;) {
 506                 /* Reboot protection */
 507                 fl->fl_u.nfs_fl.state = host->h_state;
 508                 status = nlmclnt_call(req, NLMPROC_LOCK);
 509                 if (status < 0)
 510                         goto out_unblock;
 511                 if (!req->a_args.block)
 512                         break;
 513                 /* Did a reclaimer thread notify us of a server reboot? */
 514                 if (resp->status ==  nlm_lck_denied_grace_period)
 515                         continue;
 516                 if (resp->status != nlm_lck_blocked)
 517                         break;
 518                 /* Wait on an NLM blocking lock */
 519                 status = nlmclnt_block(block, req, NLMCLNT_POLL_TIMEOUT);
 520                 /* if we were interrupted. Send a CANCEL request to the server
 521                  * and exit
 522                  */
 523                 if (status < 0)
 524                         goto out_unblock;
 525                 if (resp->status != nlm_lck_blocked)
 526                         break;
 527         }
 528
 529         if (resp->status == nlm_granted) {
 530                 down_read(&host->h_rwsem);
 531                 /* Check whether or not the server has rebooted */
 532                 if (fl->fl_u.nfs_fl.state != host->h_state) {
 533                         up_read(&host->h_rwsem);
 534                         goto again;
 535                 }
 536                 /* Ensure the resulting lock will get added to granted list */
 537                 fl->fl_flags |= FL_SLEEP;
 538                 if (do_vfs_lock(fl) < 0)
 539                         printk(KERN_WARNING "%s: VFS is out of sync with lock manager!\n", __FUNCTION__);
 540                 up_read(&host->h_rwsem);
 541                 fl->fl_flags = fl_flags;
 542         }
 543         status = nlm_stat_to_errno(resp->status);
 544 out_unblock:
 545         nlmclnt_finish_block(block);
 546         /* Cancel the blocked request if it is still pending */
 547         if (resp->status == nlm_lck_blocked)
 548                 nlmclnt_cancel(host, req->a_args.block, fl);
 549 out:
 550         nlm_release_call(req);
 551         return status;
 552 }
 553
 554 /*
 555  * RECLAIM: Try to reclaim a lock
 556  */
 557 int
 558 nlmclnt_reclaim(struct nlm_host *host, struct file_lock *fl)
 559 {
 560         struct nlm_rqst reqst, *req;
 561         int             status;
 562
 563         req = &reqst;
 564         memset(req, 0, sizeof(*req));
 565         locks_init_lock(&req->a_args.lock.fl);
 566         locks_init_lock(&req->a_res.lock.fl);
 567         req->a_host  = host;
 568         req->a_flags = 0;
 569
 570         /* Set up the argument struct */
 571         nlmclnt_setlockargs(req, fl);
 572         req->a_args.reclaim = 1;
 573
 574         if ((status = nlmclnt_call(req, NLMPROC_LOCK)) >= 0
 575          && req->a_res.status == nlm_granted)
 576                 return 0;
 577
 578         printk(KERN_WARNING "lockd: failed to reclaim lock for pid %d "
 579                                 "(errno %d, status %d)\n", fl->fl_pid,
 580                                 status, ntohl(req->a_res.status));
 581
 582         /*
 583          * FIXME: This is a serious failure. We can
 584          *
 585          *  a.  Ignore the problem
 586          *  b.  Send the owning process some signal (Linux doesn't have
 587          *      SIGLOST, though...)
 588          *  c.  Retry the operation
 589          *
 590          * Until someone comes up with a simple implementation
 591          * for b or c, I'll choose option a.
 592          */
 593
 594         return -ENOLCK;
 595 }
 596
 597 /*
 598  * UNLOCK: remove an existing lock
 599  */
 600 static int
 601 nlmclnt_unlock(struct nlm_rqst *req, struct file_lock *fl)
 602 {
 603         struct nlm_host *host = req->a_host;
 604         struct nlm_res  *resp = &req->a_res;
 605         int status;
 606         unsigned char fl_flags = fl->fl_flags;
 607
 608         /*
 609          * Note: the server is supposed to either grant us the unlock
 610          * request, or to deny it with NLM_LCK_DENIED_GRACE_PERIOD. In either
 611          * case, we want to unlock.
 612          */
 613         fl->fl_flags |= FL_EXISTS;
 614         down_read(&host->h_rwsem);
 615         status = do_vfs_lock(fl);
 616         up_read(&host->h_rwsem);
 617         fl->fl_flags = fl_flags;
 618         if (status == -ENOENT) {
 619                 status = 0;
 620                 goto out;
 621         }
 622
 623         if (req->a_flags & RPC_TASK_ASYNC)
 624                 return nlm_async_call(req, NLMPROC_UNLOCK, &nlmclnt_unlock_ops);
 625
 626         status = nlmclnt_call(req, NLMPROC_UNLOCK);
 627         if (status < 0)
 628                 goto out;
 629
 630         if (resp->status == nlm_granted)
 631                 goto out;
 632
 633         if (resp->status != nlm_lck_denied_nolocks)
 634                 printk("lockd: unexpected unlock status: %d\n", resp->status);
 635         /* What to do now? I'm out of my depth... */
 636         status = -ENOLCK;
 637 out:
 638         nlm_release_call(req);
 639         return status;
 640 }
 641
 642 static void nlmclnt_unlock_callback(struct rpc_task *task, void *data)
 643 {
 644         struct nlm_rqst *req = data;
 645         u32 status = ntohl(req->a_res.status);
 646
 647         if (RPC_ASSASSINATED(task))
 648                 goto die;
 649
 650         if (task->tk_status < 0) {
 651                 dprintk("lockd: unlock failed (err = %d)\n", -task->tk_status);
 652                 goto retry_rebind;
 653         }
 654         if (status == NLM_LCK_DENIED_GRACE_PERIOD) {
 655                 rpc_delay(task, NLMCLNT_GRACE_WAIT);
 656                 goto retry_unlock;
 657         }
 658         if (status != NLM_LCK_GRANTED)
 659                 printk(KERN_WARNING "lockd: unexpected unlock status: %d\n", status);
 660 die:
 661         return;
 662  retry_rebind:
 663         nlm_rebind_host(req->a_host);
 664  retry_unlock:
 665         rpc_restart_call(task);
 666 }
 667
 668 static const struct rpc_call_ops nlmclnt_unlock_ops = {
 669         .rpc_call_done = nlmclnt_unlock_callback,
 670         .rpc_release = nlmclnt_rpc_release,
 671 };
 672
 673 /*
 674  * Cancel a blocked lock request.
 675  * We always use an async RPC call for this in order not to hang a
 676  * process that has been Ctrl-C'ed.
 677  */
 678 static int nlmclnt_cancel(struct nlm_host *host, int block, struct file_lock *fl)
 679 {
 680         struct nlm_rqst *req;
 681         unsigned long   flags;
 682         sigset_t        oldset;
 683         int             status;
 684
 685         /* Block all signals while setting up call */
 686         spin_lock_irqsave(&current->sighand->siglock, flags);
 687         oldset = current->blocked;
 688         sigfillset(&current->blocked);
 689         recalc_sigpending();
 690         spin_unlock_irqrestore(&current->sighand->siglock, flags);
 691
 692         req = nlm_alloc_call(nlm_get_host(host));
 693         if (!req)
 694                 return -ENOMEM;
 695         req->a_flags = RPC_TASK_ASYNC;
 696
 697         nlmclnt_setlockargs(req, fl);
 698         req->a_args.block = block;
 699
 700         status = nlm_async_call(req, NLMPROC_CANCEL, &nlmclnt_cancel_ops);
 701
 702         spin_lock_irqsave(&current->sighand->siglock, flags);
 703         current->blocked = oldset;
 704         recalc_sigpending();
 705         spin_unlock_irqrestore(&current->sighand->siglock, flags);
 706
 707         return status;
 708 }
 709
 710 static void nlmclnt_cancel_callback(struct rpc_task *task, void *data)
 711 {
 712         struct nlm_rqst *req = data;
 713         u32 status = ntohl(req->a_res.status);
 714
 715         if (RPC_ASSASSINATED(task))
 716                 goto die;
 717
 718         if (task->tk_status < 0) {
 719                 dprintk("lockd: CANCEL call error %d, retrying.\n",
 720                                         task->tk_status);
 721                 goto retry_cancel;
 722         }
 723
 724         dprintk("lockd: cancel status %u (task %u)\n",
 725                         status, task->tk_pid);
 726
 727         switch (status) {
 728         case NLM_LCK_GRANTED:
 729         case NLM_LCK_DENIED_GRACE_PERIOD:
 730         case NLM_LCK_DENIED:
 731                 /* Everything's good */
 732                 break;
 733         case NLM_LCK_DENIED_NOLOCKS:
 734                 dprintk("lockd: CANCEL failed (server has no locks)\n");
 735                 goto retry_cancel;
 736         default:
 737                 printk(KERN_NOTICE "lockd: weird return %d for CANCEL call\n",
 738                         status);
 739         }
 740
 741 die:
 742         return;
 743
 744 retry_cancel:
 745         /* Don't ever retry more than 3 times */
 746         if (req->a_retries++ >= NLMCLNT_MAX_RETRIES)
 747                 goto die;
 748         nlm_rebind_host(req->a_host);
 749         rpc_restart_call(task);
 750         rpc_delay(task, 30 * HZ);
 751 }
 752
 753 static const struct rpc_call_ops nlmclnt_cancel_ops = {
 754         .rpc_call_done = nlmclnt_cancel_callback,
 755         .rpc_release = nlmclnt_rpc_release,
 756 };
 757
 758 /*
 759  * Convert an NLM status code to a generic kernel errno
 760  */
 761 static int
 762 nlm_stat_to_errno(__be32 status)
 763 {
 764         switch(ntohl(status)) {
 765         case NLM_LCK_GRANTED:
 766                 return 0;
 767         case NLM_LCK_DENIED:
 768                 return -EAGAIN;
 769         case NLM_LCK_DENIED_NOLOCKS:
 770         case NLM_LCK_DENIED_GRACE_PERIOD:
 771                 return -ENOLCK;
 772         case NLM_LCK_BLOCKED:
 773                 printk(KERN_NOTICE "lockd: unexpected status NLM_BLOCKED\n");
 774                 return -ENOLCK;
 775 #ifdef CONFIG_LOCKD_V4
 776         case NLM_DEADLCK:
 777                 return -EDEADLK;
 778         case NLM_ROFS:
 779                 return -EROFS;
 780         case NLM_STALE_FH:
 781                 return -ESTALE;
 782         case NLM_FBIG:
 783                 return -EOVERFLOW;
 784         case NLM_FAILED:
 785                 return -ENOLCK;
 786 #endif
 787         }
 788         printk(KERN_NOTICE "lockd: unexpected server status %d\n", status);
 789         return -ENOLCK;
 790 }