fs/lockd/clntproc.c

   1 /*
   2  * linux/fs/lockd/clntproc.c
   3  *
   4  * RPC procedures for the client side NLM implementation
   5  *
   6  * Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de>
   7  */
   8
   9 #include <linux/config.h>
  10 #include <linux/module.h>
  11 #include <linux/types.h>
  12 #include <linux/errno.h>
  13 #include <linux/fs.h>
  14 #include <linux/nfs_fs.h>
  15 #include <linux/utsname.h>
  16 #include <linux/smp_lock.h>
  17 #include <linux/sunrpc/clnt.h>
  18 #include <linux/sunrpc/svc.h>
  19 #include <linux/lockd/lockd.h>
  20 #include <linux/lockd/sm_inter.h>
  21
  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 nfs_server       *nfssrv = NFS_SERVER(inode);
 156         struct nlm_host         *host;
 157         struct nlm_rqst         reqst, *call = &reqst;
 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         if (!(host = nlmclnt_lookup_host(NFS_ADDR(inode), proto, vers)))
 172                 return -ENOLCK;
 173
 174         /* Create RPC client handle if not there, and copy soft
 175          * and intr flags from NFS client. */
 176         if (host->h_rpcclnt == NULL) {
 177                 struct rpc_clnt *clnt;
 178
 179                 /* Bind an rpc client to this host handle (does not
 180                  * perform a portmapper lookup) */
 181                 if (!(clnt = nlm_bind_host(host))) {
 182                         status = -ENOLCK;
 183                         goto done;
 184                 }
 185                 clnt->cl_softrtry = nfssrv->client->cl_softrtry;
 186                 clnt->cl_intr = nfssrv->client->cl_intr;
 187         }
 188
 189         /* Keep the old signal mask */
 190         spin_lock_irqsave(&current->sighand->siglock, flags);
 191         oldset = current->blocked;
 192
 193         /* If we're cleaning up locks because the process is exiting,
 194          * perform the RPC call asynchronously. */
 195         if ((IS_SETLK(cmd) || IS_SETLKW(cmd))
 196             && fl->fl_type == F_UNLCK
 197             && (current->flags & PF_EXITING)) {
 198                 sigfillset(&current->blocked);  /* Mask all signals */
 199                 recalc_sigpending();
 200                 spin_unlock_irqrestore(&current->sighand->siglock, flags);
 201
 202                 call = nlmclnt_alloc_call();
 203                 if (!call) {
 204                         status = -ENOMEM;
 205                         goto out_restore;
 206                 }
 207                 call->a_flags = RPC_TASK_ASYNC;
 208         } else {
 209                 spin_unlock_irqrestore(&current->sighand->siglock, flags);
 210                 memset(call, 0, sizeof(*call));
 211                 locks_init_lock(&call->a_args.lock.fl);
 212                 locks_init_lock(&call->a_res.lock.fl);
 213         }
 214         call->a_host = host;
 215
 216         nlmclnt_locks_init_private(fl, host);
 217
 218         /* Set up the argument struct */
 219         nlmclnt_setlockargs(call, fl);
 220
 221         if (IS_SETLK(cmd) || IS_SETLKW(cmd)) {
 222                 if (fl->fl_type != F_UNLCK) {
 223                         call->a_args.block = IS_SETLKW(cmd) ? 1 : 0;
 224                         status = nlmclnt_lock(call, fl);
 225                 } else
 226                         status = nlmclnt_unlock(call, fl);
 227         } else if (IS_GETLK(cmd))
 228                 status = nlmclnt_test(call, fl);
 229         else
 230                 status = -EINVAL;
 231
 232  out_restore:
 233         spin_lock_irqsave(&current->sighand->siglock, flags);
 234         current->blocked = oldset;
 235         recalc_sigpending();
 236         spin_unlock_irqrestore(&current->sighand->siglock, flags);
 237
 238 done:
 239         dprintk("lockd: clnt proc returns %d\n", status);
 240         nlm_release_host(host);
 241         return status;
 242 }
 243 EXPORT_SYMBOL(nlmclnt_proc);
 244
 245 /*
 246  * Allocate an NLM RPC call struct
 247  */
 248 struct nlm_rqst *
 249 nlmclnt_alloc_call(void)
 250 {
 251         struct nlm_rqst *call;
 252
 253         for(;;) {
 254                 call = kzalloc(sizeof(*call), GFP_KERNEL);
 255                 if (call != NULL) {
 256                         locks_init_lock(&call->a_args.lock.fl);
 257                         locks_init_lock(&call->a_res.lock.fl);
 258                         return call;
 259                 }
 260                 if (signalled())
 261                         break;
 262                 printk("nlmclnt_alloc_call: failed, waiting for memory\n");
 263                 schedule_timeout_interruptible(5*HZ);
 264         }
 265         return NULL;
 266 }
 267
 268 static int nlm_wait_on_grace(wait_queue_head_t *queue)
 269 {
 270         DEFINE_WAIT(wait);
 271         int status = -EINTR;
 272
 273         prepare_to_wait(queue, &wait, TASK_INTERRUPTIBLE);
 274         if (!signalled ()) {
 275                 schedule_timeout(NLMCLNT_GRACE_WAIT);
 276                 try_to_freeze();
 277                 if (!signalled ())
 278                         status = 0;
 279         }
 280         finish_wait(queue, &wait);
 281         return status;
 282 }
 283
 284 /*
 285  * Generic NLM call
 286  */
 287 static int
 288 nlmclnt_call(struct nlm_rqst *req, u32 proc)
 289 {
 290         struct nlm_host *host = req->a_host;
 291         struct rpc_clnt *clnt;
 292         struct nlm_args *argp = &req->a_args;
 293         struct nlm_res  *resp = &req->a_res;
 294         struct rpc_message msg = {
 295                 .rpc_argp       = argp,
 296                 .rpc_resp       = resp,
 297         };
 298         int             status;
 299
 300         dprintk("lockd: call procedure %d on %s\n",
 301                         (int)proc, host->h_name);
 302
 303         do {
 304                 if (host->h_reclaiming && !argp->reclaim)
 305                         goto in_grace_period;
 306
 307                 /* If we have no RPC client yet, create one. */
 308                 if ((clnt = nlm_bind_host(host)) == NULL)
 309                         return -ENOLCK;
 310                 msg.rpc_proc = &clnt->cl_procinfo[proc];
 311
 312                 /* Perform the RPC call. If an error occurs, try again */
 313                 if ((status = rpc_call_sync(clnt, &msg, 0)) < 0) {
 314                         dprintk("lockd: rpc_call returned error %d\n", -status);
 315                         switch (status) {
 316                         case -EPROTONOSUPPORT:
 317                                 status = -EINVAL;
 318                                 break;
 319                         case -ECONNREFUSED:
 320                         case -ETIMEDOUT:
 321                         case -ENOTCONN:
 322                                 nlm_rebind_host(host);
 323                                 status = -EAGAIN;
 324                                 break;
 325                         case -ERESTARTSYS:
 326                                 return signalled () ? -EINTR : status;
 327                         default:
 328                                 break;
 329                         }
 330                         break;
 331                 } else
 332                 if (resp->status == NLM_LCK_DENIED_GRACE_PERIOD) {
 333                         dprintk("lockd: server in grace period\n");
 334                         if (argp->reclaim) {
 335                                 printk(KERN_WARNING
 336                                      "lockd: spurious grace period reject?!\n");
 337                                 return -ENOLCK;
 338                         }
 339                 } else {
 340                         if (!argp->reclaim) {
 341                                 /* We appear to be out of the grace period */
 342                                 wake_up_all(&host->h_gracewait);
 343                         }
 344                         dprintk("lockd: server returns status %d\n", resp->status);
 345                         return 0;       /* Okay, call complete */
 346                 }
 347
 348 in_grace_period:
 349                 /*
 350                  * The server has rebooted and appears to be in the grace
 351                  * period during which locks are only allowed to be
 352                  * reclaimed.
 353                  * We can only back off and try again later.
 354                  */
 355                 status = nlm_wait_on_grace(&host->h_gracewait);
 356         } while (status == 0);
 357
 358         return status;
 359 }
 360
 361 /*
 362  * Generic NLM call, async version.
 363  */
 364 int nlmsvc_async_call(struct nlm_rqst *req, u32 proc, const struct rpc_call_ops *tk_ops)
 365 {
 366         struct nlm_host *host = req->a_host;
 367         struct rpc_clnt *clnt;
 368         struct rpc_message msg = {
 369                 .rpc_argp       = &req->a_args,
 370                 .rpc_resp       = &req->a_res,
 371         };
 372         int             status;
 373
 374         dprintk("lockd: call procedure %d on %s (async)\n",
 375                         (int)proc, host->h_name);
 376
 377         /* If we have no RPC client yet, create one. */
 378         if ((clnt = nlm_bind_host(host)) == NULL)
 379                 return -ENOLCK;
 380         msg.rpc_proc = &clnt->cl_procinfo[proc];
 381
 382         /* bootstrap and kick off the async RPC call */
 383         status = rpc_call_async(clnt, &msg, RPC_TASK_ASYNC, tk_ops, req);
 384
 385         return status;
 386 }
 387
 388 static int nlmclnt_async_call(struct nlm_rqst *req, u32 proc, const struct rpc_call_ops *tk_ops)
 389 {
 390         struct nlm_host *host = req->a_host;
 391         struct rpc_clnt *clnt;
 392         struct nlm_args *argp = &req->a_args;
 393         struct nlm_res  *resp = &req->a_res;
 394         struct rpc_message msg = {
 395                 .rpc_argp       = argp,
 396                 .rpc_resp       = resp,
 397         };
 398         int             status;
 399
 400         dprintk("lockd: call procedure %d on %s (async)\n",
 401                         (int)proc, host->h_name);
 402
 403         /* If we have no RPC client yet, create one. */
 404         if ((clnt = nlm_bind_host(host)) == NULL)
 405                 return -ENOLCK;
 406         msg.rpc_proc = &clnt->cl_procinfo[proc];
 407
 408         /* Increment host refcount */
 409         nlm_get_host(host);
 410         /* bootstrap and kick off the async RPC call */
 411         status = rpc_call_async(clnt, &msg, RPC_TASK_ASYNC, tk_ops, req);
 412         if (status < 0)
 413                 nlm_release_host(host);
 414         return status;
 415 }
 416
 417 /*
 418  * TEST for the presence of a conflicting lock
 419  */
 420 static int
 421 nlmclnt_test(struct nlm_rqst *req, struct file_lock *fl)
 422 {
 423         int     status;
 424
 425         status = nlmclnt_call(req, NLMPROC_TEST);
 426         nlmclnt_release_lockargs(req);
 427         if (status < 0)
 428                 return status;
 429
 430         status = req->a_res.status;
 431         if (status == NLM_LCK_GRANTED) {
 432                 fl->fl_type = F_UNLCK;
 433         } if (status == NLM_LCK_DENIED) {
 434                 /*
 435                  * Report the conflicting lock back to the application.
 436                  */
 437                 locks_copy_lock(fl, &req->a_res.lock.fl);
 438                 fl->fl_pid = 0;
 439         } else {
 440                 return nlm_stat_to_errno(req->a_res.status);
 441         }
 442
 443         return 0;
 444 }
 445
 446 static void nlmclnt_locks_copy_lock(struct file_lock *new, struct file_lock *fl)
 447 {
 448         new->fl_u.nfs_fl.state = fl->fl_u.nfs_fl.state;
 449         new->fl_u.nfs_fl.owner = nlm_get_lockowner(fl->fl_u.nfs_fl.owner);
 450         list_add_tail(&new->fl_u.nfs_fl.list, &fl->fl_u.nfs_fl.owner->host->h_granted);
 451 }
 452
 453 static void nlmclnt_locks_release_private(struct file_lock *fl)
 454 {
 455         list_del(&fl->fl_u.nfs_fl.list);
 456         nlm_put_lockowner(fl->fl_u.nfs_fl.owner);
 457 }
 458
 459 static struct file_lock_operations nlmclnt_lock_ops = {
 460         .fl_copy_lock = nlmclnt_locks_copy_lock,
 461         .fl_release_private = nlmclnt_locks_release_private,
 462 };
 463
 464 static void nlmclnt_locks_init_private(struct file_lock *fl, struct nlm_host *host)
 465 {
 466         BUG_ON(fl->fl_ops != NULL);
 467         fl->fl_u.nfs_fl.state = 0;
 468         fl->fl_u.nfs_fl.owner = nlm_find_lockowner(host, fl->fl_owner);
 469         INIT_LIST_HEAD(&fl->fl_u.nfs_fl.list);
 470         fl->fl_ops = &nlmclnt_lock_ops;
 471 }
 472
 473 static void do_vfs_lock(struct file_lock *fl)
 474 {
 475         int res = 0;
 476         switch (fl->fl_flags & (FL_POSIX|FL_FLOCK)) {
 477                 case FL_POSIX:
 478                         res = posix_lock_file_wait(fl->fl_file, fl);
 479                         break;
 480                 case FL_FLOCK:
 481                         res = flock_lock_file_wait(fl->fl_file, fl);
 482                         break;
 483                 default:
 484                         BUG();
 485         }
 486         if (res < 0)
 487                 printk(KERN_WARNING "%s: VFS is out of sync with lock manager!\n",
 488                                 __FUNCTION__);
 489 }
 490
 491 /*
 492  * LOCK: Try to create a lock
 493  *
 494  *                      Programmer Harassment Alert
 495  *
 496  * When given a blocking lock request in a sync RPC call, the HPUX lockd
 497  * will faithfully return LCK_BLOCKED but never cares to notify us when
 498  * the lock could be granted. This way, our local process could hang
 499  * around forever waiting for the callback.
 500  *
 501  *  Solution A: Implement busy-waiting
 502  *  Solution B: Use the async version of the call (NLM_LOCK_{MSG,RES})
 503  *
 504  * For now I am implementing solution A, because I hate the idea of
 505  * re-implementing lockd for a third time in two months. The async
 506  * calls shouldn't be too hard to do, however.
 507  *
 508  * This is one of the lovely things about standards in the NFS area:
 509  * they're so soft and squishy you can't really blame HP for doing this.
 510  */
 511 static int
 512 nlmclnt_lock(struct nlm_rqst *req, struct file_lock *fl)
 513 {
 514         struct nlm_host *host = req->a_host;
 515         struct nlm_res  *resp = &req->a_res;
 516         struct nlm_wait *block = NULL;
 517         int status = -ENOLCK;
 518
 519         if (!host->h_monitored && nsm_monitor(host) < 0) {
 520                 printk(KERN_NOTICE "lockd: failed to monitor %s\n",
 521                                         host->h_name);
 522                 goto out;
 523         }
 524
 525         block = nlmclnt_prepare_block(host, fl);
 526         for(;;) {
 527                 status = nlmclnt_call(req, NLMPROC_LOCK);
 528                 if (status < 0)
 529                         goto out_unblock;
 530                 if (!req->a_args.block)
 531                         break;
 532                 /* Did a reclaimer thread notify us of a server reboot? */
 533                 if (resp->status ==  NLM_LCK_DENIED_GRACE_PERIOD)
 534                         continue;
 535                 if (resp->status != NLM_LCK_BLOCKED)
 536                         break;
 537                 /* Wait on an NLM blocking lock */
 538                 status = nlmclnt_block(block, req, NLMCLNT_POLL_TIMEOUT);
 539                 /* if we were interrupted. Send a CANCEL request to the server
 540                  * and exit
 541                  */
 542                 if (status < 0)
 543                         goto out_unblock;
 544                 if (resp->status != NLM_LCK_BLOCKED)
 545                         break;
 546         }
 547
 548         if (resp->status == NLM_LCK_GRANTED) {
 549                 fl->fl_u.nfs_fl.state = host->h_state;
 550                 fl->fl_flags |= FL_SLEEP;
 551                 /* Ensure the resulting lock will get added to granted list */
 552                 do_vfs_lock(fl);
 553         }
 554         status = nlm_stat_to_errno(resp->status);
 555 out_unblock:
 556         nlmclnt_finish_block(block);
 557         /* Cancel the blocked request if it is still pending */
 558         if (resp->status == NLM_LCK_BLOCKED)
 559                 nlmclnt_cancel(host, req->a_args.block, fl);
 560 out:
 561         nlmclnt_release_lockargs(req);
 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_res  *resp = &req->a_res;
 615         int             status;
 616
 617         /*
 618          * Note: the server is supposed to either grant us the unlock
 619          * request, or to deny it with NLM_LCK_DENIED_GRACE_PERIOD. In either
 620          * case, we want to unlock.
 621          */
 622         do_vfs_lock(fl);
 623
 624         if (req->a_flags & RPC_TASK_ASYNC) {
 625                 status = nlmclnt_async_call(req, NLMPROC_UNLOCK,
 626                                         &nlmclnt_unlock_ops);
 627                 /* Hrmf... Do the unlock early since locks_remove_posix()
 628                  * really expects us to free the lock synchronously */
 629                 if (status < 0) {
 630                         nlmclnt_release_lockargs(req);
 631                         kfree(req);
 632                 }
 633                 return status;
 634         }
 635
 636         status = nlmclnt_call(req, NLMPROC_UNLOCK);
 637         nlmclnt_release_lockargs(req);
 638         if (status < 0)
 639                 return status;
 640
 641         if (resp->status == NLM_LCK_GRANTED)
 642                 return 0;
 643
 644         if (resp->status != NLM_LCK_DENIED_NOLOCKS)
 645                 printk("lockd: unexpected unlock status: %d\n", resp->status);
 646
 647         /* What to do now? I'm out of my depth... */
 648
 649         return -ENOLCK;
 650 }
 651
 652 static void nlmclnt_unlock_callback(struct rpc_task *task, void *data)
 653 {
 654         struct nlm_rqst *req = data;
 655         int             status = req->a_res.status;
 656
 657         if (RPC_ASSASSINATED(task))
 658                 goto die;
 659
 660         if (task->tk_status < 0) {
 661                 dprintk("lockd: unlock failed (err = %d)\n", -task->tk_status);
 662                 goto retry_rebind;
 663         }
 664         if (status == NLM_LCK_DENIED_GRACE_PERIOD) {
 665                 rpc_delay(task, NLMCLNT_GRACE_WAIT);
 666                 goto retry_unlock;
 667         }
 668         if (status != NLM_LCK_GRANTED)
 669                 printk(KERN_WARNING "lockd: unexpected unlock status: %d\n", status);
 670 die:
 671         nlm_release_host(req->a_host);
 672         nlmclnt_release_lockargs(req);
 673         kfree(req);
 674         return;
 675  retry_rebind:
 676         nlm_rebind_host(req->a_host);
 677  retry_unlock:
 678         rpc_restart_call(task);
 679 }
 680
 681 static const struct rpc_call_ops nlmclnt_unlock_ops = {
 682         .rpc_call_done = nlmclnt_unlock_callback,
 683 };
 684
 685 /*
 686  * Cancel a blocked lock request.
 687  * We always use an async RPC call for this in order not to hang a
 688  * process that has been Ctrl-C'ed.
 689  */
 690 static int nlmclnt_cancel(struct nlm_host *host, int block, struct file_lock *fl)
 691 {
 692         struct nlm_rqst *req;
 693         unsigned long   flags;
 694         sigset_t        oldset;
 695         int             status;
 696
 697         /* Block all signals while setting up call */
 698         spin_lock_irqsave(&current->sighand->siglock, flags);
 699         oldset = current->blocked;
 700         sigfillset(&current->blocked);
 701         recalc_sigpending();
 702         spin_unlock_irqrestore(&current->sighand->siglock, flags);
 703
 704         req = nlmclnt_alloc_call();
 705         if (!req)
 706                 return -ENOMEM;
 707         req->a_host  = host;
 708         req->a_flags = RPC_TASK_ASYNC;
 709
 710         nlmclnt_setlockargs(req, fl);
 711         req->a_args.block = block;
 712
 713         status = nlmclnt_async_call(req, NLMPROC_CANCEL, &nlmclnt_cancel_ops);
 714         if (status < 0) {
 715                 nlmclnt_release_lockargs(req);
 716                 kfree(req);
 717         }
 718
 719         spin_lock_irqsave(&current->sighand->siglock, flags);
 720         current->blocked = oldset;
 721         recalc_sigpending();
 722         spin_unlock_irqrestore(&current->sighand->siglock, flags);
 723
 724         return status;
 725 }
 726
 727 static void nlmclnt_cancel_callback(struct rpc_task *task, void *data)
 728 {
 729         struct nlm_rqst *req = data;
 730
 731         if (RPC_ASSASSINATED(task))
 732                 goto die;
 733
 734         if (task->tk_status < 0) {
 735                 dprintk("lockd: CANCEL call error %d, retrying.\n",
 736                                         task->tk_status);
 737                 goto retry_cancel;
 738         }
 739
 740         dprintk("lockd: cancel status %d (task %d)\n",
 741                         req->a_res.status, task->tk_pid);
 742
 743         switch (req->a_res.status) {
 744         case NLM_LCK_GRANTED:
 745         case NLM_LCK_DENIED_GRACE_PERIOD:
 746         case NLM_LCK_DENIED:
 747                 /* Everything's good */
 748                 break;
 749         case NLM_LCK_DENIED_NOLOCKS:
 750                 dprintk("lockd: CANCEL failed (server has no locks)\n");
 751                 goto retry_cancel;
 752         default:
 753                 printk(KERN_NOTICE "lockd: weird return %d for CANCEL call\n",
 754                         req->a_res.status);
 755         }
 756
 757 die:
 758         nlm_release_host(req->a_host);
 759         nlmclnt_release_lockargs(req);
 760         kfree(req);
 761         return;
 762
 763 retry_cancel:
 764         /* Don't ever retry more than 3 times */
 765         if (req->a_retries++ >= NLMCLNT_MAX_RETRIES)
 766                 goto die;
 767         nlm_rebind_host(req->a_host);
 768         rpc_restart_call(task);
 769         rpc_delay(task, 30 * HZ);
 770 }
 771
 772 static const struct rpc_call_ops nlmclnt_cancel_ops = {
 773         .rpc_call_done = nlmclnt_cancel_callback,
 774 };
 775
 776 /*
 777  * Convert an NLM status code to a generic kernel errno
 778  */
 779 static int
 780 nlm_stat_to_errno(u32 status)
 781 {
 782         switch(status) {
 783         case NLM_LCK_GRANTED:
 784                 return 0;
 785         case NLM_LCK_DENIED:
 786                 return -EAGAIN;
 787         case NLM_LCK_DENIED_NOLOCKS:
 788         case NLM_LCK_DENIED_GRACE_PERIOD:
 789                 return -ENOLCK;
 790         case NLM_LCK_BLOCKED:
 791                 printk(KERN_NOTICE "lockd: unexpected status NLM_BLOCKED\n");
 792                 return -ENOLCK;
 793 #ifdef CONFIG_LOCKD_V4
 794         case NLM_DEADLCK:
 795                 return -EDEADLK;
 796         case NLM_ROFS:
 797                 return -EROFS;
 798         case NLM_STALE_FH:
 799                 return -ESTALE;
 800         case NLM_FBIG:
 801                 return -EOVERFLOW;
 802         case NLM_FAILED:
 803                 return -ENOLCK;
 804 #endif
 805         }
 806         printk(KERN_NOTICE "lockd: unexpected server status %d\n", status);
 807         return -ENOLCK;
 808 }