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
  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(u32 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 u32      nlm_cookie = 0x1234;
  40
  41 static inline void nlmclnt_next_cookie(struct nlm_cookie *c)
  42 {
  43         memcpy(c->data, &nlm_cookie, 4);
  44         memset(c->data+4, 0, 4);
  45         c->len=4;
  46         nlm_cookie++;
  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 = (struct nlm_lockowner *)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_dentry->d_inode), sizeof(struct nfs_fh));
 132         lock->caller  = system_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                                 system_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  * This is the main entry point for the NLM client.
 150  */
 151 int
 152 nlmclnt_proc(struct inode *inode, int cmd, struct file_lock *fl)
 153 {
 154         struct nlm_host         *host;
 155         struct nlm_rqst         *call;
 156         sigset_t                oldset;
 157         unsigned long           flags;
 158         int                     status, proto, vers;
 159
 160         vers = (NFS_PROTO(inode)->version == 3) ? 4 : 1;
 161         if (NFS_PROTO(inode)->version > 3) {
 162                 printk(KERN_NOTICE "NFSv4 file locking not implemented!\n");
 163                 return -ENOLCK;
 164         }
 165
 166         /* Retrieve transport protocol from NFS client */
 167         proto = NFS_CLIENT(inode)->cl_xprt->prot;
 168
 169         host = nlmclnt_lookup_host(NFS_ADDR(inode), proto, vers);
 170         if (host == NULL)
 171                 return -ENOLCK;
 172
 173         call = nlm_alloc_call(host);
 174         if (call == NULL)
 175                 return -ENOMEM;
 176
 177         nlmclnt_locks_init_private(fl, host);
 178         /* Set up the argument struct */
 179         nlmclnt_setlockargs(call, fl);
 180
 181         /* Keep the old signal mask */
 182         spin_lock_irqsave(&current->sighand->siglock, flags);
 183         oldset = current->blocked;
 184
 185         /* If we're cleaning up locks because the process is exiting,
 186          * perform the RPC call asynchronously. */
 187         if ((IS_SETLK(cmd) || IS_SETLKW(cmd))
 188             && fl->fl_type == F_UNLCK
 189             && (current->flags & PF_EXITING)) {
 190                 sigfillset(&current->blocked);  /* Mask all signals */
 191                 recalc_sigpending();
 192
 193                 call->a_flags = RPC_TASK_ASYNC;
 194         }
 195         spin_unlock_irqrestore(&current->sighand->siglock, flags);
 196
 197         if (IS_SETLK(cmd) || IS_SETLKW(cmd)) {
 198                 if (fl->fl_type != F_UNLCK) {
 199                         call->a_args.block = IS_SETLKW(cmd) ? 1 : 0;
 200                         status = nlmclnt_lock(call, fl);
 201                 } else
 202                         status = nlmclnt_unlock(call, fl);
 203         } else if (IS_GETLK(cmd))
 204                 status = nlmclnt_test(call, fl);
 205         else
 206                 status = -EINVAL;
 207
 208         fl->fl_ops->fl_release_private(fl);
 209         fl->fl_ops = NULL;
 210
 211         spin_lock_irqsave(&current->sighand->siglock, flags);
 212         current->blocked = oldset;
 213         recalc_sigpending();
 214         spin_unlock_irqrestore(&current->sighand->siglock, flags);
 215
 216         dprintk("lockd: clnt proc returns %d\n", status);
 217         return status;
 218 }
 219 EXPORT_SYMBOL(nlmclnt_proc);
 220
 221 /*
 222  * Allocate an NLM RPC call struct
 223  *
 224  * Note: the caller must hold a reference to host. In case of failure,
 225  * this reference will be released.
 226  */
 227 struct nlm_rqst *nlm_alloc_call(struct nlm_host *host)
 228 {
 229         struct nlm_rqst *call;
 230
 231         for(;;) {
 232                 call = kzalloc(sizeof(*call), GFP_KERNEL);
 233                 if (call != NULL) {
 234                         locks_init_lock(&call->a_args.lock.fl);
 235                         locks_init_lock(&call->a_res.lock.fl);
 236                         call->a_host = host;
 237                         return call;
 238                 }
 239                 if (signalled())
 240                         break;
 241                 printk("nlm_alloc_call: failed, waiting for memory\n");
 242                 schedule_timeout_interruptible(5*HZ);
 243         }
 244         nlm_release_host(host);
 245         return NULL;
 246 }
 247
 248 void nlm_release_call(struct nlm_rqst *call)
 249 {
 250         nlm_release_host(call->a_host);
 251         nlmclnt_release_lockargs(call);
 252         kfree(call);
 253 }
 254
 255 static void nlmclnt_rpc_release(void *data)
 256 {
 257         return nlm_release_call(data);
 258 }
 259
 260 static int nlm_wait_on_grace(wait_queue_head_t *queue)
 261 {
 262         DEFINE_WAIT(wait);
 263         int status = -EINTR;
 264
 265         prepare_to_wait(queue, &wait, TASK_INTERRUPTIBLE);
 266         if (!signalled ()) {
 267                 schedule_timeout(NLMCLNT_GRACE_WAIT);
 268                 try_to_freeze();
 269                 if (!signalled ())
 270                         status = 0;
 271         }
 272         finish_wait(queue, &wait);
 273         return status;
 274 }
 275
 276 /*
 277  * Generic NLM call
 278  */
 279 static int
 280 nlmclnt_call(struct nlm_rqst *req, u32 proc)
 281 {
 282         struct nlm_host *host = req->a_host;
 283         struct rpc_clnt *clnt;
 284         struct nlm_args *argp = &req->a_args;
 285         struct nlm_res  *resp = &req->a_res;
 286         struct rpc_message msg = {
 287                 .rpc_argp       = argp,
 288                 .rpc_resp       = resp,
 289         };
 290         int             status;
 291
 292         dprintk("lockd: call procedure %d on %s\n",
 293                         (int)proc, host->h_name);
 294
 295         do {
 296                 if (host->h_reclaiming && !argp->reclaim)
 297                         goto in_grace_period;
 298
 299                 /* If we have no RPC client yet, create one. */
 300                 if ((clnt = nlm_bind_host(host)) == NULL)
 301                         return -ENOLCK;
 302                 msg.rpc_proc = &clnt->cl_procinfo[proc];
 303
 304                 /* Perform the RPC call. If an error occurs, try again */
 305                 if ((status = rpc_call_sync(clnt, &msg, 0)) < 0) {
 306                         dprintk("lockd: rpc_call returned error %d\n", -status);
 307                         switch (status) {
 308                         case -EPROTONOSUPPORT:
 309                                 status = -EINVAL;
 310                                 break;
 311                         case -ECONNREFUSED:
 312                         case -ETIMEDOUT:
 313                         case -ENOTCONN:
 314                                 nlm_rebind_host(host);
 315                                 status = -EAGAIN;
 316                                 break;
 317                         case -ERESTARTSYS:
 318                                 return signalled () ? -EINTR : status;
 319                         default:
 320                                 break;
 321                         }
 322                         break;
 323                 } else
 324                 if (resp->status == NLM_LCK_DENIED_GRACE_PERIOD) {
 325                         dprintk("lockd: server in grace period\n");
 326                         if (argp->reclaim) {
 327                                 printk(KERN_WARNING
 328                                      "lockd: spurious grace period reject?!\n");
 329                                 return -ENOLCK;
 330                         }
 331                 } else {
 332                         if (!argp->reclaim) {
 333                                 /* We appear to be out of the grace period */
 334                                 wake_up_all(&host->h_gracewait);
 335                         }
 336                         dprintk("lockd: server returns status %d\n", resp->status);
 337                         return 0;       /* Okay, call complete */
 338                 }
 339
 340 in_grace_period:
 341                 /*
 342                  * The server has rebooted and appears to be in the grace
 343                  * period during which locks are only allowed to be
 344                  * reclaimed.
 345                  * We can only back off and try again later.
 346                  */
 347                 status = nlm_wait_on_grace(&host->h_gracewait);
 348         } while (status == 0);
 349
 350         return status;
 351 }
 352
 353 /*
 354  * Generic NLM call, async version.
 355  */
 356 static int __nlm_async_call(struct nlm_rqst *req, u32 proc, struct rpc_message *msg, const struct rpc_call_ops *tk_ops)
 357 {
 358         struct nlm_host *host = req->a_host;
 359         struct rpc_clnt *clnt;
 360         int status = -ENOLCK;
 361
 362         dprintk("lockd: call procedure %d on %s (async)\n",
 363                         (int)proc, host->h_name);
 364
 365         /* If we have no RPC client yet, create one. */
 366         clnt = nlm_bind_host(host);
 367         if (clnt == NULL)
 368                 goto out_err;
 369         msg->rpc_proc = &clnt->cl_procinfo[proc];
 370
 371         /* bootstrap and kick off the async RPC call */
 372         status = rpc_call_async(clnt, msg, RPC_TASK_ASYNC, tk_ops, req);
 373         if (status == 0)
 374                 return 0;
 375 out_err:
 376         nlm_release_call(req);
 377         return status;
 378 }
 379
 380 int nlm_async_call(struct nlm_rqst *req, u32 proc, const struct rpc_call_ops *tk_ops)
 381 {
 382         struct rpc_message msg = {
 383                 .rpc_argp       = &req->a_args,
 384                 .rpc_resp       = &req->a_res,
 385         };
 386         return __nlm_async_call(req, proc, &msg, tk_ops);
 387 }
 388
 389 int nlm_async_reply(struct nlm_rqst *req, u32 proc, const struct rpc_call_ops *tk_ops)
 390 {
 391         struct rpc_message msg = {
 392                 .rpc_argp       = &req->a_res,
 393         };
 394         return __nlm_async_call(req, proc, &msg, tk_ops);
 395 }
 396
 397 /*
 398  * TEST for the presence of a conflicting lock
 399  */
 400 static int
 401 nlmclnt_test(struct nlm_rqst *req, struct file_lock *fl)
 402 {
 403         int     status;
 404
 405         status = nlmclnt_call(req, NLMPROC_TEST);
 406         if (status < 0)
 407                 goto out;
 408
 409         switch (req->a_res.status) {
 410                 case NLM_LCK_GRANTED:
 411                         fl->fl_type = F_UNLCK;
 412                         break;
 413                 case NLM_LCK_DENIED:
 414                         /*
 415                          * Report the conflicting lock back to the application.
 416                          */
 417                         fl->fl_start = req->a_res.lock.fl.fl_start;
 418                         fl->fl_end = req->a_res.lock.fl.fl_start;
 419                         fl->fl_type = req->a_res.lock.fl.fl_type;
 420                         fl->fl_pid = 0;
 421                         break;
 422                 default:
 423                         status = nlm_stat_to_errno(req->a_res.status);
 424         }
 425 out:
 426         nlm_release_call(req);
 427         return status;
 428 }
 429
 430 static void nlmclnt_locks_copy_lock(struct file_lock *new, struct file_lock *fl)
 431 {
 432         new->fl_u.nfs_fl.state = fl->fl_u.nfs_fl.state;
 433         new->fl_u.nfs_fl.owner = nlm_get_lockowner(fl->fl_u.nfs_fl.owner);
 434         list_add_tail(&new->fl_u.nfs_fl.list, &fl->fl_u.nfs_fl.owner->host->h_granted);
 435 }
 436
 437 static void nlmclnt_locks_release_private(struct file_lock *fl)
 438 {
 439         list_del(&fl->fl_u.nfs_fl.list);
 440         nlm_put_lockowner(fl->fl_u.nfs_fl.owner);
 441 }
 442
 443 static struct file_lock_operations nlmclnt_lock_ops = {
 444         .fl_copy_lock = nlmclnt_locks_copy_lock,
 445         .fl_release_private = nlmclnt_locks_release_private,
 446 };
 447
 448 static void nlmclnt_locks_init_private(struct file_lock *fl, struct nlm_host *host)
 449 {
 450         BUG_ON(fl->fl_ops != NULL);
 451         fl->fl_u.nfs_fl.state = 0;
 452         fl->fl_u.nfs_fl.owner = nlm_find_lockowner(host, fl->fl_owner);
 453         INIT_LIST_HEAD(&fl->fl_u.nfs_fl.list);
 454         fl->fl_ops = &nlmclnt_lock_ops;
 455 }
 456
 457 static void do_vfs_lock(struct file_lock *fl)
 458 {
 459         int res = 0;
 460         switch (fl->fl_flags & (FL_POSIX|FL_FLOCK)) {
 461                 case FL_POSIX:
 462                         res = posix_lock_file_wait(fl->fl_file, fl);
 463                         break;
 464                 case FL_FLOCK:
 465                         res = flock_lock_file_wait(fl->fl_file, fl);
 466                         break;
 467                 default:
 468                         BUG();
 469         }
 470         if (res < 0)
 471                 printk(KERN_WARNING "%s: VFS is out of sync with lock manager!\n",
 472                                 __FUNCTION__);
 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         int status = -ENOLCK;
 502
 503         if (!host->h_monitored && nsm_monitor(host) < 0) {
 504                 printk(KERN_NOTICE "lockd: failed to monitor %s\n",
 505                                         host->h_name);
 506                 goto out;
 507         }
 508
 509         block = nlmclnt_prepare_block(host, fl);
 510 again:
 511         for(;;) {
 512                 /* Reboot protection */
 513                 fl->fl_u.nfs_fl.state = host->h_state;
 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                 down_read(&host->h_rwsem);
 537                 /* Check whether or not the server has rebooted */
 538                 if (fl->fl_u.nfs_fl.state != host->h_state) {
 539                         up_read(&host->h_rwsem);
 540                         goto again;
 541                 }
 542                 fl->fl_flags |= FL_SLEEP;
 543                 /* Ensure the resulting lock will get added to granted list */
 544                 do_vfs_lock(fl);
 545                 up_read(&host->h_rwsem);
 546         }
 547         status = nlm_stat_to_errno(resp->status);
 548 out_unblock:
 549         nlmclnt_finish_block(block);
 550         /* Cancel the blocked request if it is still pending */
 551         if (resp->status == NLM_LCK_BLOCKED)
 552                 nlmclnt_cancel(host, req->a_args.block, fl);
 553 out:
 554         nlm_release_call(req);
 555         return status;
 556 }
 557
 558 /*
 559  * RECLAIM: Try to reclaim a lock
 560  */
 561 int
 562 nlmclnt_reclaim(struct nlm_host *host, struct file_lock *fl)
 563 {
 564         struct nlm_rqst reqst, *req;
 565         int             status;
 566
 567         req = &reqst;
 568         memset(req, 0, sizeof(*req));
 569         locks_init_lock(&req->a_args.lock.fl);
 570         locks_init_lock(&req->a_res.lock.fl);
 571         req->a_host  = host;
 572         req->a_flags = 0;
 573
 574         /* Set up the argument struct */
 575         nlmclnt_setlockargs(req, fl);
 576         req->a_args.reclaim = 1;
 577
 578         if ((status = nlmclnt_call(req, NLMPROC_LOCK)) >= 0
 579          && req->a_res.status == NLM_LCK_GRANTED)
 580                 return 0;
 581
 582         printk(KERN_WARNING "lockd: failed to reclaim lock for pid %d "
 583                                 "(errno %d, status %d)\n", fl->fl_pid,
 584                                 status, req->a_res.status);
 585
 586         /*
 587          * FIXME: This is a serious failure. We can
 588          *
 589          *  a.  Ignore the problem
 590          *  b.  Send the owning process some signal (Linux doesn't have
 591          *      SIGLOST, though...)
 592          *  c.  Retry the operation
 593          *
 594          * Until someone comes up with a simple implementation
 595          * for b or c, I'll choose option a.
 596          */
 597
 598         return -ENOLCK;
 599 }
 600
 601 /*
 602  * UNLOCK: remove an existing lock
 603  */
 604 static int
 605 nlmclnt_unlock(struct nlm_rqst *req, struct file_lock *fl)
 606 {
 607         struct nlm_host *host = req->a_host;
 608         struct nlm_res  *resp = &req->a_res;
 609         int             status;
 610
 611         /*
 612          * Note: the server is supposed to either grant us the unlock
 613          * request, or to deny it with NLM_LCK_DENIED_GRACE_PERIOD. In either
 614          * case, we want to unlock.
 615          */
 616         down_read(&host->h_rwsem);
 617         do_vfs_lock(fl);
 618         up_read(&host->h_rwsem);
 619
 620         if (req->a_flags & RPC_TASK_ASYNC)
 621                 return nlm_async_call(req, NLMPROC_UNLOCK, &nlmclnt_unlock_ops);
 622
 623         status = nlmclnt_call(req, NLMPROC_UNLOCK);
 624         if (status < 0)
 625                 goto out;
 626
 627         status = 0;
 628         if (resp->status == NLM_LCK_GRANTED)
 629                 goto out;
 630
 631         if (resp->status != NLM_LCK_DENIED_NOLOCKS)
 632                 printk("lockd: unexpected unlock status: %d\n", resp->status);
 633         /* What to do now? I'm out of my depth... */
 634         status = -ENOLCK;
 635 out:
 636         nlm_release_call(req);
 637         return status;
 638 }
 639
 640 static void nlmclnt_unlock_callback(struct rpc_task *task, void *data)
 641 {
 642         struct nlm_rqst *req = data;
 643         int             status = req->a_res.status;
 644
 645         if (RPC_ASSASSINATED(task))
 646                 goto die;
 647
 648         if (task->tk_status < 0) {
 649                 dprintk("lockd: unlock failed (err = %d)\n", -task->tk_status);
 650                 goto retry_rebind;
 651         }
 652         if (status == NLM_LCK_DENIED_GRACE_PERIOD) {
 653                 rpc_delay(task, NLMCLNT_GRACE_WAIT);
 654                 goto retry_unlock;
 655         }
 656         if (status != NLM_LCK_GRANTED)
 657                 printk(KERN_WARNING "lockd: unexpected unlock status: %d\n", status);
 658 die:
 659         return;
 660  retry_rebind:
 661         nlm_rebind_host(req->a_host);
 662  retry_unlock:
 663         rpc_restart_call(task);
 664 }
 665
 666 static const struct rpc_call_ops nlmclnt_unlock_ops = {
 667         .rpc_call_done = nlmclnt_unlock_callback,
 668         .rpc_release = nlmclnt_rpc_release,
 669 };
 670
 671 /*
 672  * Cancel a blocked lock request.
 673  * We always use an async RPC call for this in order not to hang a
 674  * process that has been Ctrl-C'ed.
 675  */
 676 static int nlmclnt_cancel(struct nlm_host *host, int block, struct file_lock *fl)
 677 {
 678         struct nlm_rqst *req;
 679         unsigned long   flags;
 680         sigset_t        oldset;
 681         int             status;
 682
 683         /* Block all signals while setting up call */
 684         spin_lock_irqsave(&current->sighand->siglock, flags);
 685         oldset = current->blocked;
 686         sigfillset(&current->blocked);
 687         recalc_sigpending();
 688         spin_unlock_irqrestore(&current->sighand->siglock, flags);
 689
 690         req = nlm_alloc_call(nlm_get_host(host));
 691         if (!req)
 692                 return -ENOMEM;
 693         req->a_flags = RPC_TASK_ASYNC;
 694
 695         nlmclnt_setlockargs(req, fl);
 696         req->a_args.block = block;
 697
 698         status = nlm_async_call(req, NLMPROC_CANCEL, &nlmclnt_cancel_ops);
 699
 700         spin_lock_irqsave(&current->sighand->siglock, flags);
 701         current->blocked = oldset;
 702         recalc_sigpending();
 703         spin_unlock_irqrestore(&current->sighand->siglock, flags);
 704
 705         return status;
 706 }
 707
 708 static void nlmclnt_cancel_callback(struct rpc_task *task, void *data)
 709 {
 710         struct nlm_rqst *req = data;
 711
 712         if (RPC_ASSASSINATED(task))
 713                 goto die;
 714
 715         if (task->tk_status < 0) {
 716                 dprintk("lockd: CANCEL call error %d, retrying.\n",
 717                                         task->tk_status);
 718                 goto retry_cancel;
 719         }
 720
 721         dprintk("lockd: cancel status %d (task %d)\n",
 722                         req->a_res.status, task->tk_pid);
 723
 724         switch (req->a_res.status) {
 725         case NLM_LCK_GRANTED:
 726         case NLM_LCK_DENIED_GRACE_PERIOD:
 727         case NLM_LCK_DENIED:
 728                 /* Everything's good */
 729                 break;
 730         case NLM_LCK_DENIED_NOLOCKS:
 731                 dprintk("lockd: CANCEL failed (server has no locks)\n");
 732                 goto retry_cancel;
 733         default:
 734                 printk(KERN_NOTICE "lockd: weird return %d for CANCEL call\n",
 735                         req->a_res.status);
 736         }
 737
 738 die:
 739         return;
 740
 741 retry_cancel:
 742         /* Don't ever retry more than 3 times */
 743         if (req->a_retries++ >= NLMCLNT_MAX_RETRIES)
 744                 goto die;
 745         nlm_rebind_host(req->a_host);
 746         rpc_restart_call(task);
 747         rpc_delay(task, 30 * HZ);
 748 }
 749
 750 static const struct rpc_call_ops nlmclnt_cancel_ops = {
 751         .rpc_call_done = nlmclnt_cancel_callback,
 752         .rpc_release = nlmclnt_rpc_release,
 753 };
 754
 755 /*
 756  * Convert an NLM status code to a generic kernel errno
 757  */
 758 static int
 759 nlm_stat_to_errno(u32 status)
 760 {
 761         switch(status) {
 762         case NLM_LCK_GRANTED:
 763                 return 0;
 764         case NLM_LCK_DENIED:
 765                 return -EAGAIN;
 766         case NLM_LCK_DENIED_NOLOCKS:
 767         case NLM_LCK_DENIED_GRACE_PERIOD:
 768                 return -ENOLCK;
 769         case NLM_LCK_BLOCKED:
 770                 printk(KERN_NOTICE "lockd: unexpected status NLM_BLOCKED\n");
 771                 return -ENOLCK;
 772 #ifdef CONFIG_LOCKD_V4
 773         case NLM_DEADLCK:
 774                 return -EDEADLK;
 775         case NLM_ROFS:
 776                 return -EROFS;
 777         case NLM_STALE_FH:
 778                 return -ESTALE;
 779         case NLM_FBIG:
 780                 return -EOVERFLOW;
 781         case NLM_FAILED:
 782                 return -ENOLCK;
 783 #endif
 784         }
 785         printk(KERN_NOTICE "lockd: unexpected server status %d\n", status);
 786         return -ENOLCK;
 787 }