err.no Git - linux-2.6/blob - 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         locks_copy_lock(&lock->fl, fl);
 140 }
 141
 142 static void nlmclnt_release_lockargs(struct nlm_rqst *req)
 143 {
 144         struct file_lock *fl = &req->a_args.lock.fl;
 145
 146         if (fl->fl_ops && fl->fl_ops->fl_release_private)
 147                 fl->fl_ops->fl_release_private(fl);
 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 nfs_server       *nfssrv = NFS_SERVER(inode);
 157         struct nlm_host         *host;
 158         struct nlm_rqst         reqst, *call = &reqst;
 159         sigset_t                oldset;
 160         unsigned long           flags;
 161         int                     status, proto, vers;
 162
 163         vers = (NFS_PROTO(inode)->version == 3) ? 4 : 1;
 164         if (NFS_PROTO(inode)->version > 3) {
 165                 printk(KERN_NOTICE "NFSv4 file locking not implemented!\n");
 166                 return -ENOLCK;
 167         }
 168
 169         /* Retrieve transport protocol from NFS client */
 170         proto = NFS_CLIENT(inode)->cl_xprt->prot;
 171
 172         if (!(host = nlmclnt_lookup_host(NFS_ADDR(inode), proto, vers)))
 173                 return -ENOLCK;
 174
 175         /* Create RPC client handle if not there, and copy soft
 176          * and intr flags from NFS client. */
 177         if (host->h_rpcclnt == NULL) {
 178                 struct rpc_clnt *clnt;
 179
 180                 /* Bind an rpc client to this host handle (does not
 181                  * perform a portmapper lookup) */
 182                 if (!(clnt = nlm_bind_host(host))) {
 183                         status = -ENOLCK;
 184                         goto done;
 185                 }
 186                 clnt->cl_softrtry = nfssrv->client->cl_softrtry;
 187                 clnt->cl_intr = nfssrv->client->cl_intr;
 188         }
 189
 190         /* Keep the old signal mask */
 191         spin_lock_irqsave(&current->sighand->siglock, flags);
 192         oldset = current->blocked;
 193
 194         /* If we're cleaning up locks because the process is exiting,
 195          * perform the RPC call asynchronously. */
 196         if ((IS_SETLK(cmd) || IS_SETLKW(cmd))
 197             && fl->fl_type == F_UNLCK
 198             && (current->flags & PF_EXITING)) {
 199                 sigfillset(&current->blocked);  /* Mask all signals */
 200                 recalc_sigpending();
 201                 spin_unlock_irqrestore(&current->sighand->siglock, flags);
 202
 203                 call = nlmclnt_alloc_call();
 204                 if (!call) {
 205                         status = -ENOMEM;
 206                         goto out_restore;
 207                 }
 208                 call->a_flags = RPC_TASK_ASYNC;
 209         } else {
 210                 spin_unlock_irqrestore(&current->sighand->siglock, flags);
 211                 memset(call, 0, sizeof(*call));
 212                 locks_init_lock(&call->a_args.lock.fl);
 213                 locks_init_lock(&call->a_res.lock.fl);
 214         }
 215         call->a_host = host;
 216
 217         nlmclnt_locks_init_private(fl, host);
 218
 219         /* Set up the argument struct */
 220         nlmclnt_setlockargs(call, fl);
 221
 222         if (IS_SETLK(cmd) || IS_SETLKW(cmd)) {
 223                 if (fl->fl_type != F_UNLCK) {
 224                         call->a_args.block = IS_SETLKW(cmd) ? 1 : 0;
 225                         status = nlmclnt_lock(call, fl);
 226                 } else
 227                         status = nlmclnt_unlock(call, fl);
 228         } else if (IS_GETLK(cmd))
 229                 status = nlmclnt_test(call, fl);
 230         else
 231                 status = -EINVAL;
 232
 233  out_restore:
 234         spin_lock_irqsave(&current->sighand->siglock, flags);
 235         current->blocked = oldset;
 236         recalc_sigpending();
 237         spin_unlock_irqrestore(&current->sighand->siglock, flags);
 238
 239 done:
 240         dprintk("lockd: clnt proc returns %d\n", status);
 241         nlm_release_host(host);
 242         return status;
 243 }
 244 EXPORT_SYMBOL(nlmclnt_proc);
 245
 246 /*
 247  * Allocate an NLM RPC call struct
 248  */
 249 struct nlm_rqst *
 250 nlmclnt_alloc_call(void)
 251 {
 252         struct nlm_rqst *call;
 253
 254         for(;;) {
 255                 call = kzalloc(sizeof(*call), GFP_KERNEL);
 256                 if (call != NULL) {
 257                         locks_init_lock(&call->a_args.lock.fl);
 258                         locks_init_lock(&call->a_res.lock.fl);
 259                         return call;
 260                 }
 261                 if (signalled())
 262                         break;
 263                 printk("nlmclnt_alloc_call: failed, waiting for memory\n");
 264                 schedule_timeout_interruptible(5*HZ);
 265         }
 266         return NULL;
 267 }
 268
 269 static int nlm_wait_on_grace(wait_queue_head_t *queue)
 270 {
 271         DEFINE_WAIT(wait);
 272         int status = -EINTR;
 273
 274         prepare_to_wait(queue, &wait, TASK_INTERRUPTIBLE);
 275         if (!signalled ()) {
 276                 schedule_timeout(NLMCLNT_GRACE_WAIT);
 277                 try_to_freeze();
 278                 if (!signalled ())
 279                         status = 0;
 280         }
 281         finish_wait(queue, &wait);
 282         return status;
 283 }
 284
 285 /*
 286  * Generic NLM call
 287  */
 288 static int
 289 nlmclnt_call(struct nlm_rqst *req, u32 proc)
 290 {
 291         struct nlm_host *host = req->a_host;
 292         struct rpc_clnt *clnt;
 293         struct nlm_args *argp = &req->a_args;
 294         struct nlm_res  *resp = &req->a_res;
 295         struct rpc_message msg = {
 296                 .rpc_argp       = argp,
 297                 .rpc_resp       = resp,
 298         };
 299         int             status;
 300
 301         dprintk("lockd: call procedure %d on %s\n",
 302                         (int)proc, host->h_name);
 303
 304         do {
 305                 if (host->h_reclaiming && !argp->reclaim)
 306                         goto in_grace_period;
 307
 308                 /* If we have no RPC client yet, create one. */
 309                 if ((clnt = nlm_bind_host(host)) == NULL)
 310                         return -ENOLCK;
 311                 msg.rpc_proc = &clnt->cl_procinfo[proc];
 312
 313                 /* Perform the RPC call. If an error occurs, try again */
 314                 if ((status = rpc_call_sync(clnt, &msg, 0)) < 0) {
 315                         dprintk("lockd: rpc_call returned error %d\n", -status);
 316                         switch (status) {
 317                         case -EPROTONOSUPPORT:
 318                                 status = -EINVAL;
 319                                 break;
 320                         case -ECONNREFUSED:
 321                         case -ETIMEDOUT:
 322                         case -ENOTCONN:
 323                                 nlm_rebind_host(host);
 324                                 status = -EAGAIN;
 325                                 break;
 326                         case -ERESTARTSYS:
 327                                 return signalled () ? -EINTR : status;
 328                         default:
 329                                 break;
 330                         }
 331                         break;
 332                 } else
 333                 if (resp->status == NLM_LCK_DENIED_GRACE_PERIOD) {
 334                         dprintk("lockd: server in grace period\n");
 335                         if (argp->reclaim) {
 336                                 printk(KERN_WARNING
 337                                      "lockd: spurious grace period reject?!\n");
 338                                 return -ENOLCK;
 339                         }
 340                 } else {
 341                         if (!argp->reclaim) {
 342                                 /* We appear to be out of the grace period */
 343                                 wake_up_all(&host->h_gracewait);
 344                         }
 345                         dprintk("lockd: server returns status %d\n", resp->status);
 346                         return 0;       /* Okay, call complete */
 347                 }
 348
 349 in_grace_period:
 350                 /*
 351                  * The server has rebooted and appears to be in the grace
 352                  * period during which locks are only allowed to be
 353                  * reclaimed.
 354                  * We can only back off and try again later.
 355                  */
 356                 status = nlm_wait_on_grace(&host->h_gracewait);
 357         } while (status == 0);
 358
 359         return status;
 360 }
 361
 362 /*
 363  * Generic NLM call, async version.
 364  */
 365 int nlmsvc_async_call(struct nlm_rqst *req, u32 proc, const struct rpc_call_ops *tk_ops)
 366 {
 367         struct nlm_host *host = req->a_host;
 368         struct rpc_clnt *clnt;
 369         struct rpc_message msg = {
 370                 .rpc_argp       = &req->a_args,
 371                 .rpc_resp       = &req->a_res,
 372         };
 373         int             status;
 374
 375         dprintk("lockd: call procedure %d on %s (async)\n",
 376                         (int)proc, host->h_name);
 377
 378         /* If we have no RPC client yet, create one. */
 379         if ((clnt = nlm_bind_host(host)) == NULL)
 380                 return -ENOLCK;
 381         msg.rpc_proc = &clnt->cl_procinfo[proc];
 382
 383         /* bootstrap and kick off the async RPC call */
 384         status = rpc_call_async(clnt, &msg, RPC_TASK_ASYNC, tk_ops, req);
 385
 386         return status;
 387 }
 388
 389 static int nlmclnt_async_call(struct nlm_rqst *req, u32 proc, const struct rpc_call_ops *tk_ops)
 390 {
 391         struct nlm_host *host = req->a_host;
 392         struct rpc_clnt *clnt;
 393         struct nlm_args *argp = &req->a_args;
 394         struct nlm_res  *resp = &req->a_res;
 395         struct rpc_message msg = {
 396                 .rpc_argp       = argp,
 397                 .rpc_resp       = resp,
 398         };
 399         int             status;
 400
 401         dprintk("lockd: call procedure %d on %s (async)\n",
 402                         (int)proc, host->h_name);
 403
 404         /* If we have no RPC client yet, create one. */
 405         if ((clnt = nlm_bind_host(host)) == NULL)
 406                 return -ENOLCK;
 407         msg.rpc_proc = &clnt->cl_procinfo[proc];
 408
 409         /* Increment host refcount */
 410         nlm_get_host(host);
 411         /* bootstrap and kick off the async RPC call */
 412         status = rpc_call_async(clnt, &msg, RPC_TASK_ASYNC, tk_ops, req);
 413         if (status < 0)
 414                 nlm_release_host(host);
 415         return status;
 416 }
 417
 418 /*
 419  * TEST for the presence of a conflicting lock
 420  */
 421 static int
 422 nlmclnt_test(struct nlm_rqst *req, struct file_lock *fl)
 423 {
 424         int     status;
 425
 426         status = nlmclnt_call(req, NLMPROC_TEST);
 427         nlmclnt_release_lockargs(req);
 428         if (status < 0)
 429                 return status;
 430
 431         status = req->a_res.status;
 432         if (status == NLM_LCK_GRANTED) {
 433                 fl->fl_type = F_UNLCK;
 434         } if (status == NLM_LCK_DENIED) {
 435                 /*
 436                  * Report the conflicting lock back to the application.
 437                  */
 438                 locks_copy_lock(fl, &req->a_res.lock.fl);
 439                 fl->fl_pid = 0;
 440         } else {
 441                 return nlm_stat_to_errno(req->a_res.status);
 442         }
 443
 444         return 0;
 445 }
 446
 447 static void nlmclnt_locks_copy_lock(struct file_lock *new, struct file_lock *fl)
 448 {
 449         new->fl_u.nfs_fl.state = fl->fl_u.nfs_fl.state;
 450         new->fl_u.nfs_fl.owner = nlm_get_lockowner(fl->fl_u.nfs_fl.owner);
 451         list_add_tail(&new->fl_u.nfs_fl.list, &fl->fl_u.nfs_fl.owner->host->h_granted);
 452 }
 453
 454 static void nlmclnt_locks_release_private(struct file_lock *fl)
 455 {
 456         list_del(&fl->fl_u.nfs_fl.list);
 457         nlm_put_lockowner(fl->fl_u.nfs_fl.owner);
 458         fl->fl_ops = NULL;
 459 }
 460
 461 static struct file_lock_operations nlmclnt_lock_ops = {
 462         .fl_copy_lock = nlmclnt_locks_copy_lock,
 463         .fl_release_private = nlmclnt_locks_release_private,
 464 };
 465
 466 static void nlmclnt_locks_init_private(struct file_lock *fl, struct nlm_host *host)
 467 {
 468         BUG_ON(fl->fl_ops != NULL);
 469         fl->fl_u.nfs_fl.state = 0;
 470         fl->fl_u.nfs_fl.owner = nlm_find_lockowner(host, fl->fl_owner);
 471         INIT_LIST_HEAD(&fl->fl_u.nfs_fl.list);
 472         fl->fl_ops = &nlmclnt_lock_ops;
 473 }
 474
 475 static void do_vfs_lock(struct file_lock *fl)
 476 {
 477         int res = 0;
 478         switch (fl->fl_flags & (FL_POSIX|FL_FLOCK)) {
 479                 case FL_POSIX:
 480                         res = posix_lock_file_wait(fl->fl_file, fl);
 481                         break;
 482                 case FL_FLOCK:
 483                         res = flock_lock_file_wait(fl->fl_file, fl);
 484                         break;
 485                 default:
 486                         BUG();
 487         }
 488         if (res < 0)
 489                 printk(KERN_WARNING "%s: VFS is out of sync with lock manager!\n",
 490                                 __FUNCTION__);
 491 }
 492
 493 /*
 494  * LOCK: Try to create a lock
 495  *
 496  *                      Programmer Harassment Alert
 497  *
 498  * When given a blocking lock request in a sync RPC call, the HPUX lockd
 499  * will faithfully return LCK_BLOCKED but never cares to notify us when
 500  * the lock could be granted. This way, our local process could hang
 501  * around forever waiting for the callback.
 502  *
 503  *  Solution A: Implement busy-waiting
 504  *  Solution B: Use the async version of the call (NLM_LOCK_{MSG,RES})
 505  *
 506  * For now I am implementing solution A, because I hate the idea of
 507  * re-implementing lockd for a third time in two months. The async
 508  * calls shouldn't be too hard to do, however.
 509  *
 510  * This is one of the lovely things about standards in the NFS area:
 511  * they're so soft and squishy you can't really blame HP for doing this.
 512  */
 513 static int
 514 nlmclnt_lock(struct nlm_rqst *req, struct file_lock *fl)
 515 {
 516         struct nlm_host *host = req->a_host;
 517         struct nlm_res  *resp = &req->a_res;
 518         long timeout;
 519         int status;
 520
 521         if (!host->h_monitored && nsm_monitor(host) < 0) {
 522                 printk(KERN_NOTICE "lockd: failed to monitor %s\n",
 523                                         host->h_name);
 524                 status = -ENOLCK;
 525                 goto out;
 526         }
 527
 528         if (req->a_args.block) {
 529                 status = nlmclnt_prepare_block(req, host, fl);
 530                 if (status < 0)
 531                         goto out;
 532         }
 533         for(;;) {
 534                 status = nlmclnt_call(req, NLMPROC_LOCK);
 535                 if (status < 0)
 536                         goto out_unblock;
 537                 if (resp->status != NLM_LCK_BLOCKED)
 538                         break;
 539                 /* Wait on an NLM blocking lock */
 540                 timeout = nlmclnt_block(req, NLMCLNT_POLL_TIMEOUT);
 541                 /* Did a reclaimer thread notify us of a server reboot? */
 542                 if (resp->status ==  NLM_LCK_DENIED_GRACE_PERIOD)
 543                         continue;
 544                 if (resp->status != NLM_LCK_BLOCKED)
 545                         break;
 546                 if (timeout >= 0)
 547                         continue;
 548                 /* We were interrupted. Send a CANCEL request to the server
 549                  * and exit
 550                  */
 551                 status = (int)timeout;
 552                 goto out_unblock;
 553         }
 554
 555         if (resp->status == NLM_LCK_GRANTED) {
 556                 fl->fl_u.nfs_fl.state = host->h_state;
 557                 fl->fl_flags |= FL_SLEEP;
 558                 /* Ensure the resulting lock will get added to granted list */
 559                 do_vfs_lock(fl);
 560         }
 561         status = nlm_stat_to_errno(resp->status);
 562 out_unblock:
 563         nlmclnt_finish_block(req);
 564         /* Cancel the blocked request if it is still pending */
 565         if (resp->status == NLM_LCK_BLOCKED)
 566                 nlmclnt_cancel(host, req->a_args.block, fl);
 567 out:
 568         nlmclnt_release_lockargs(req);
 569         return status;
 570 }
 571
 572 /*
 573  * RECLAIM: Try to reclaim a lock
 574  */
 575 int
 576 nlmclnt_reclaim(struct nlm_host *host, struct file_lock *fl)
 577 {
 578         struct nlm_rqst reqst, *req;
 579         int             status;
 580
 581         req = &reqst;
 582         memset(req, 0, sizeof(*req));
 583         locks_init_lock(&req->a_args.lock.fl);
 584         locks_init_lock(&req->a_res.lock.fl);
 585         req->a_host  = host;
 586         req->a_flags = 0;
 587
 588         /* Set up the argument struct */
 589         nlmclnt_setlockargs(req, fl);
 590         req->a_args.reclaim = 1;
 591
 592         if ((status = nlmclnt_call(req, NLMPROC_LOCK)) >= 0
 593          && req->a_res.status == NLM_LCK_GRANTED)
 594                 return 0;
 595
 596         printk(KERN_WARNING "lockd: failed to reclaim lock for pid %d "
 597                                 "(errno %d, status %d)\n", fl->fl_pid,
 598                                 status, req->a_res.status);
 599
 600         /*
 601          * FIXME: This is a serious failure. We can
 602          *
 603          *  a.  Ignore the problem
 604          *  b.  Send the owning process some signal (Linux doesn't have
 605          *      SIGLOST, though...)
 606          *  c.  Retry the operation
 607          *
 608          * Until someone comes up with a simple implementation
 609          * for b or c, I'll choose option a.
 610          */
 611
 612         return -ENOLCK;
 613 }
 614
 615 /*
 616  * UNLOCK: remove an existing lock
 617  */
 618 static int
 619 nlmclnt_unlock(struct nlm_rqst *req, struct file_lock *fl)
 620 {
 621         struct nlm_res  *resp = &req->a_res;
 622         int             status;
 623
 624         /*
 625          * Note: the server is supposed to either grant us the unlock
 626          * request, or to deny it with NLM_LCK_DENIED_GRACE_PERIOD. In either
 627          * case, we want to unlock.
 628          */
 629         do_vfs_lock(fl);
 630
 631         if (req->a_flags & RPC_TASK_ASYNC) {
 632                 status = nlmclnt_async_call(req, NLMPROC_UNLOCK,
 633                                         &nlmclnt_unlock_ops);
 634                 /* Hrmf... Do the unlock early since locks_remove_posix()
 635                  * really expects us to free the lock synchronously */
 636                 if (status < 0) {
 637                         nlmclnt_release_lockargs(req);
 638                         kfree(req);
 639                 }
 640                 return status;
 641         }
 642
 643         status = nlmclnt_call(req, NLMPROC_UNLOCK);
 644         nlmclnt_release_lockargs(req);
 645         if (status < 0)
 646                 return status;
 647
 648         if (resp->status == NLM_LCK_GRANTED)
 649                 return 0;
 650
 651         if (resp->status != NLM_LCK_DENIED_NOLOCKS)
 652                 printk("lockd: unexpected unlock status: %d\n", resp->status);
 653
 654         /* What to do now? I'm out of my depth... */
 655
 656         return -ENOLCK;
 657 }
 658
 659 static void nlmclnt_unlock_callback(struct rpc_task *task, void *data)
 660 {
 661         struct nlm_rqst *req = data;
 662         int             status = req->a_res.status;
 663
 664         if (RPC_ASSASSINATED(task))
 665                 goto die;
 666
 667         if (task->tk_status < 0) {
 668                 dprintk("lockd: unlock failed (err = %d)\n", -task->tk_status);
 669                 goto retry_rebind;
 670         }
 671         if (status == NLM_LCK_DENIED_GRACE_PERIOD) {
 672                 rpc_delay(task, NLMCLNT_GRACE_WAIT);
 673                 goto retry_unlock;
 674         }
 675         if (status != NLM_LCK_GRANTED)
 676                 printk(KERN_WARNING "lockd: unexpected unlock status: %d\n", status);
 677 die:
 678         nlm_release_host(req->a_host);
 679         nlmclnt_release_lockargs(req);
 680         kfree(req);
 681         return;
 682  retry_rebind:
 683         nlm_rebind_host(req->a_host);
 684  retry_unlock:
 685         rpc_restart_call(task);
 686 }
 687
 688 static const struct rpc_call_ops nlmclnt_unlock_ops = {
 689         .rpc_call_done = nlmclnt_unlock_callback,
 690 };
 691
 692 /*
 693  * Cancel a blocked lock request.
 694  * We always use an async RPC call for this in order not to hang a
 695  * process that has been Ctrl-C'ed.
 696  */
 697 static int nlmclnt_cancel(struct nlm_host *host, int block, struct file_lock *fl)
 698 {
 699         struct nlm_rqst *req;
 700         unsigned long   flags;
 701         sigset_t        oldset;
 702         int             status;
 703
 704         /* Block all signals while setting up call */
 705         spin_lock_irqsave(&current->sighand->siglock, flags);
 706         oldset = current->blocked;
 707         sigfillset(&current->blocked);
 708         recalc_sigpending();
 709         spin_unlock_irqrestore(&current->sighand->siglock, flags);
 710
 711         req = nlmclnt_alloc_call();
 712         if (!req)
 713                 return -ENOMEM;
 714         req->a_host  = host;
 715         req->a_flags = RPC_TASK_ASYNC;
 716
 717         nlmclnt_setlockargs(req, fl);
 718         req->a_args.block = block;
 719
 720         status = nlmclnt_async_call(req, NLMPROC_CANCEL, &nlmclnt_cancel_ops);
 721         if (status < 0) {
 722                 nlmclnt_release_lockargs(req);
 723                 kfree(req);
 724         }
 725
 726         spin_lock_irqsave(&current->sighand->siglock, flags);
 727         current->blocked = oldset;
 728         recalc_sigpending();
 729         spin_unlock_irqrestore(&current->sighand->siglock, flags);
 730
 731         return status;
 732 }
 733
 734 static void nlmclnt_cancel_callback(struct rpc_task *task, void *data)
 735 {
 736         struct nlm_rqst *req = data;
 737
 738         if (RPC_ASSASSINATED(task))
 739                 goto die;
 740
 741         if (task->tk_status < 0) {
 742                 dprintk("lockd: CANCEL call error %d, retrying.\n",
 743                                         task->tk_status);
 744                 goto retry_cancel;
 745         }
 746
 747         dprintk("lockd: cancel status %d (task %d)\n",
 748                         req->a_res.status, task->tk_pid);
 749
 750         switch (req->a_res.status) {
 751         case NLM_LCK_GRANTED:
 752         case NLM_LCK_DENIED_GRACE_PERIOD:
 753                 /* Everything's good */
 754                 break;
 755         case NLM_LCK_DENIED_NOLOCKS:
 756                 dprintk("lockd: CANCEL failed (server has no locks)\n");
 757                 goto retry_cancel;
 758         default:
 759                 printk(KERN_NOTICE "lockd: weird return %d for CANCEL call\n",
 760                         req->a_res.status);
 761         }
 762
 763 die:
 764         nlm_release_host(req->a_host);
 765         nlmclnt_release_lockargs(req);
 766         kfree(req);
 767         return;
 768
 769 retry_cancel:
 770         /* Don't ever retry more than 3 times */
 771         if (req->a_retries++ >= NLMCLNT_MAX_RETRIES)
 772                 goto die;
 773         nlm_rebind_host(req->a_host);
 774         rpc_restart_call(task);
 775         rpc_delay(task, 30 * HZ);
 776 }
 777
 778 static const struct rpc_call_ops nlmclnt_cancel_ops = {
 779         .rpc_call_done = nlmclnt_cancel_callback,
 780 };
 781
 782 /*
 783  * Convert an NLM status code to a generic kernel errno
 784  */
 785 static int
 786 nlm_stat_to_errno(u32 status)
 787 {
 788         switch(status) {
 789         case NLM_LCK_GRANTED:
 790                 return 0;
 791         case NLM_LCK_DENIED:
 792                 return -EAGAIN;
 793         case NLM_LCK_DENIED_NOLOCKS:
 794         case NLM_LCK_DENIED_GRACE_PERIOD:
 795                 return -ENOLCK;
 796         case NLM_LCK_BLOCKED:
 797                 printk(KERN_NOTICE "lockd: unexpected status NLM_BLOCKED\n");
 798                 return -ENOLCK;
 799 #ifdef CONFIG_LOCKD_V4
 800         case NLM_DEADLCK:
 801                 return -EDEADLK;
 802         case NLM_ROFS:
 803                 return -EROFS;
 804         case NLM_STALE_FH:
 805                 return -ESTALE;
 806         case NLM_FBIG:
 807                 return -EOVERFLOW;
 808         case NLM_FAILED:
 809                 return -ENOLCK;
 810 #endif
 811         }
 812         printk(KERN_NOTICE "lockd: unexpected server status %d\n", status);
 813         return -ENOLCK;
 814 }