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
  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 void     nlmclnt_unlock_callback(struct rpc_task *);
  30 static void     nlmclnt_cancel_callback(struct rpc_task *);
  31 static int      nlm_stat_to_errno(u32 stat);
  32 static void     nlmclnt_locks_init_private(struct file_lock *fl, struct nlm_host *host);
  33
  34 /*
  35  * Cookie counter for NLM requests
  36  */
  37 static u32      nlm_cookie = 0x1234;
  38
  39 static inline void nlmclnt_next_cookie(struct nlm_cookie *c)
  40 {
  41         memcpy(c->data, &nlm_cookie, 4);
  42         memset(c->data+4, 0, 4);
  43         c->len=4;
  44         nlm_cookie++;
  45 }
  46
  47 static struct nlm_lockowner *nlm_get_lockowner(struct nlm_lockowner *lockowner)
  48 {
  49         atomic_inc(&lockowner->count);
  50         return lockowner;
  51 }
  52
  53 static void nlm_put_lockowner(struct nlm_lockowner *lockowner)
  54 {
  55         if (!atomic_dec_and_lock(&lockowner->count, &lockowner->host->h_lock))
  56                 return;
  57         list_del(&lockowner->list);
  58         spin_unlock(&lockowner->host->h_lock);
  59         nlm_release_host(lockowner->host);
  60         kfree(lockowner);
  61 }
  62
  63 static inline int nlm_pidbusy(struct nlm_host *host, uint32_t pid)
  64 {
  65         struct nlm_lockowner *lockowner;
  66         list_for_each_entry(lockowner, &host->h_lockowners, list) {
  67                 if (lockowner->pid == pid)
  68                         return -EBUSY;
  69         }
  70         return 0;
  71 }
  72
  73 static inline uint32_t __nlm_alloc_pid(struct nlm_host *host)
  74 {
  75         uint32_t res;
  76         do {
  77                 res = host->h_pidcount++;
  78         } while (nlm_pidbusy(host, res) < 0);
  79         return res;
  80 }
  81
  82 static struct nlm_lockowner *__nlm_find_lockowner(struct nlm_host *host, fl_owner_t owner)
  83 {
  84         struct nlm_lockowner *lockowner;
  85         list_for_each_entry(lockowner, &host->h_lockowners, list) {
  86                 if (lockowner->owner != owner)
  87                         continue;
  88                 return nlm_get_lockowner(lockowner);
  89         }
  90         return NULL;
  91 }
  92
  93 static struct nlm_lockowner *nlm_find_lockowner(struct nlm_host *host, fl_owner_t owner)
  94 {
  95         struct nlm_lockowner *res, *new = NULL;
  96
  97         spin_lock(&host->h_lock);
  98         res = __nlm_find_lockowner(host, owner);
  99         if (res == NULL) {
 100                 spin_unlock(&host->h_lock);
 101                 new = (struct nlm_lockowner *)kmalloc(sizeof(*new), GFP_KERNEL);
 102                 spin_lock(&host->h_lock);
 103                 res = __nlm_find_lockowner(host, owner);
 104                 if (res == NULL && new != NULL) {
 105                         res = new;
 106                         atomic_set(&new->count, 1);
 107                         new->owner = owner;
 108                         new->pid = __nlm_alloc_pid(host);
 109                         new->host = nlm_get_host(host);
 110                         list_add(&new->list, &host->h_lockowners);
 111                         new = NULL;
 112                 }
 113         }
 114         spin_unlock(&host->h_lock);
 115         kfree(new);
 116         return res;
 117 }
 118
 119 /*
 120  * Initialize arguments for TEST/LOCK/UNLOCK/CANCEL calls
 121  */
 122 static void nlmclnt_setlockargs(struct nlm_rqst *req, struct file_lock *fl)
 123 {
 124         struct nlm_args *argp = &req->a_args;
 125         struct nlm_lock *lock = &argp->lock;
 126
 127         nlmclnt_next_cookie(&argp->cookie);
 128         argp->state   = nsm_local_state;
 129         memcpy(&lock->fh, NFS_FH(fl->fl_file->f_dentry->d_inode), sizeof(struct nfs_fh));
 130         lock->caller  = system_utsname.nodename;
 131         lock->oh.data = req->a_owner;
 132         lock->oh.len  = sprintf(req->a_owner, "%d@%s",
 133                                 current->pid, system_utsname.nodename);
 134         locks_copy_lock(&lock->fl, fl);
 135 }
 136
 137 static void nlmclnt_release_lockargs(struct nlm_rqst *req)
 138 {
 139         struct file_lock *fl = &req->a_args.lock.fl;
 140
 141         if (fl->fl_ops && fl->fl_ops->fl_release_private)
 142                 fl->fl_ops->fl_release_private(fl);
 143 }
 144
 145 /*
 146  * Initialize arguments for GRANTED call. The nlm_rqst structure
 147  * has been cleared already.
 148  */
 149 int
 150 nlmclnt_setgrantargs(struct nlm_rqst *call, struct nlm_lock *lock)
 151 {
 152         locks_copy_lock(&call->a_args.lock.fl, &lock->fl);
 153         memcpy(&call->a_args.lock.fh, &lock->fh, sizeof(call->a_args.lock.fh));
 154         call->a_args.lock.caller = system_utsname.nodename;
 155         call->a_args.lock.oh.len = lock->oh.len;
 156
 157         /* set default data area */
 158         call->a_args.lock.oh.data = call->a_owner;
 159
 160         if (lock->oh.len > NLMCLNT_OHSIZE) {
 161                 void *data = kmalloc(lock->oh.len, GFP_KERNEL);
 162                 if (!data) {
 163                         nlmclnt_freegrantargs(call);
 164                         return 0;
 165                 }
 166                 call->a_args.lock.oh.data = (u8 *) data;
 167         }
 168
 169         memcpy(call->a_args.lock.oh.data, lock->oh.data, lock->oh.len);
 170         return 1;
 171 }
 172
 173 void
 174 nlmclnt_freegrantargs(struct nlm_rqst *call)
 175 {
 176         struct file_lock *fl = &call->a_args.lock.fl;
 177         /*
 178          * Check whether we allocated memory for the owner.
 179          */
 180         if (call->a_args.lock.oh.data != (u8 *) call->a_owner) {
 181                 kfree(call->a_args.lock.oh.data);
 182         }
 183         if (fl->fl_ops && fl->fl_ops->fl_release_private)
 184                 fl->fl_ops->fl_release_private(fl);
 185 }
 186
 187 /*
 188  * This is the main entry point for the NLM client.
 189  */
 190 int
 191 nlmclnt_proc(struct inode *inode, int cmd, struct file_lock *fl)
 192 {
 193         struct nfs_server       *nfssrv = NFS_SERVER(inode);
 194         struct nlm_host         *host;
 195         struct nlm_rqst         reqst, *call = &reqst;
 196         sigset_t                oldset;
 197         unsigned long           flags;
 198         int                     status, proto, vers;
 199
 200         vers = (NFS_PROTO(inode)->version == 3) ? 4 : 1;
 201         if (NFS_PROTO(inode)->version > 3) {
 202                 printk(KERN_NOTICE "NFSv4 file locking not implemented!\n");
 203                 return -ENOLCK;
 204         }
 205
 206         /* Retrieve transport protocol from NFS client */
 207         proto = NFS_CLIENT(inode)->cl_xprt->prot;
 208
 209         if (!(host = nlmclnt_lookup_host(NFS_ADDR(inode), proto, vers)))
 210                 return -ENOLCK;
 211
 212         /* Create RPC client handle if not there, and copy soft
 213          * and intr flags from NFS client. */
 214         if (host->h_rpcclnt == NULL) {
 215                 struct rpc_clnt *clnt;
 216
 217                 /* Bind an rpc client to this host handle (does not
 218                  * perform a portmapper lookup) */
 219                 if (!(clnt = nlm_bind_host(host))) {
 220                         status = -ENOLCK;
 221                         goto done;
 222                 }
 223                 clnt->cl_softrtry = nfssrv->client->cl_softrtry;
 224                 clnt->cl_intr     = nfssrv->client->cl_intr;
 225                 clnt->cl_chatty   = nfssrv->client->cl_chatty;
 226         }
 227
 228         /* Keep the old signal mask */
 229         spin_lock_irqsave(&current->sighand->siglock, flags);
 230         oldset = current->blocked;
 231
 232         /* If we're cleaning up locks because the process is exiting,
 233          * perform the RPC call asynchronously. */
 234         if ((IS_SETLK(cmd) || IS_SETLKW(cmd))
 235             && fl->fl_type == F_UNLCK
 236             && (current->flags & PF_EXITING)) {
 237                 sigfillset(&current->blocked);  /* Mask all signals */
 238                 recalc_sigpending();
 239                 spin_unlock_irqrestore(&current->sighand->siglock, flags);
 240
 241                 call = nlmclnt_alloc_call();
 242                 if (!call) {
 243                         status = -ENOMEM;
 244                         goto out_restore;
 245                 }
 246                 call->a_flags = RPC_TASK_ASYNC;
 247         } else {
 248                 spin_unlock_irqrestore(&current->sighand->siglock, flags);
 249                 memset(call, 0, sizeof(*call));
 250                 locks_init_lock(&call->a_args.lock.fl);
 251                 locks_init_lock(&call->a_res.lock.fl);
 252         }
 253         call->a_host = host;
 254
 255         nlmclnt_locks_init_private(fl, host);
 256
 257         /* Set up the argument struct */
 258         nlmclnt_setlockargs(call, fl);
 259
 260         if (IS_SETLK(cmd) || IS_SETLKW(cmd)) {
 261                 if (fl->fl_type != F_UNLCK) {
 262                         call->a_args.block = IS_SETLKW(cmd) ? 1 : 0;
 263                         status = nlmclnt_lock(call, fl);
 264                 } else
 265                         status = nlmclnt_unlock(call, fl);
 266         } else if (IS_GETLK(cmd))
 267                 status = nlmclnt_test(call, fl);
 268         else
 269                 status = -EINVAL;
 270
 271  out_restore:
 272         spin_lock_irqsave(&current->sighand->siglock, flags);
 273         current->blocked = oldset;
 274         recalc_sigpending();
 275         spin_unlock_irqrestore(&current->sighand->siglock, flags);
 276
 277 done:
 278         dprintk("lockd: clnt proc returns %d\n", status);
 279         nlm_release_host(host);
 280         return status;
 281 }
 282 EXPORT_SYMBOL(nlmclnt_proc);
 283
 284 /*
 285  * Allocate an NLM RPC call struct
 286  */
 287 struct nlm_rqst *
 288 nlmclnt_alloc_call(void)
 289 {
 290         struct nlm_rqst *call;
 291
 292         while (!signalled()) {
 293                 call = (struct nlm_rqst *) kmalloc(sizeof(struct nlm_rqst), GFP_KERNEL);
 294                 if (call) {
 295                         memset(call, 0, sizeof(*call));
 296                         locks_init_lock(&call->a_args.lock.fl);
 297                         locks_init_lock(&call->a_res.lock.fl);
 298                         return call;
 299                 }
 300                 printk("nlmclnt_alloc_call: failed, waiting for memory\n");
 301                 schedule_timeout_interruptible(5*HZ);
 302         }
 303         return NULL;
 304 }
 305
 306 static int nlm_wait_on_grace(wait_queue_head_t *queue)
 307 {
 308         DEFINE_WAIT(wait);
 309         int status = -EINTR;
 310
 311         prepare_to_wait(queue, &wait, TASK_INTERRUPTIBLE);
 312         if (!signalled ()) {
 313                 schedule_timeout(NLMCLNT_GRACE_WAIT);
 314                 try_to_freeze();
 315                 if (!signalled ())
 316                         status = 0;
 317         }
 318         finish_wait(queue, &wait);
 319         return status;
 320 }
 321
 322 /*
 323  * Generic NLM call
 324  */
 325 static int
 326 nlmclnt_call(struct nlm_rqst *req, u32 proc)
 327 {
 328         struct nlm_host *host = req->a_host;
 329         struct rpc_clnt *clnt;
 330         struct nlm_args *argp = &req->a_args;
 331         struct nlm_res  *resp = &req->a_res;
 332         struct rpc_message msg = {
 333                 .rpc_argp       = argp,
 334                 .rpc_resp       = resp,
 335         };
 336         int             status;
 337
 338         dprintk("lockd: call procedure %d on %s\n",
 339                         (int)proc, host->h_name);
 340
 341         do {
 342                 if (host->h_reclaiming && !argp->reclaim)
 343                         goto in_grace_period;
 344
 345                 /* If we have no RPC client yet, create one. */
 346                 if ((clnt = nlm_bind_host(host)) == NULL)
 347                         return -ENOLCK;
 348                 msg.rpc_proc = &clnt->cl_procinfo[proc];
 349
 350                 /* Perform the RPC call. If an error occurs, try again */
 351                 if ((status = rpc_call_sync(clnt, &msg, 0)) < 0) {
 352                         dprintk("lockd: rpc_call returned error %d\n", -status);
 353                         switch (status) {
 354                         case -EPROTONOSUPPORT:
 355                                 status = -EINVAL;
 356                                 break;
 357                         case -ECONNREFUSED:
 358                         case -ETIMEDOUT:
 359                         case -ENOTCONN:
 360                                 nlm_rebind_host(host);
 361                                 status = -EAGAIN;
 362                                 break;
 363                         case -ERESTARTSYS:
 364                                 return signalled () ? -EINTR : status;
 365                         default:
 366                                 break;
 367                         }
 368                         break;
 369                 } else
 370                 if (resp->status == NLM_LCK_DENIED_GRACE_PERIOD) {
 371                         dprintk("lockd: server in grace period\n");
 372                         if (argp->reclaim) {
 373                                 printk(KERN_WARNING
 374                                      "lockd: spurious grace period reject?!\n");
 375                                 return -ENOLCK;
 376                         }
 377                 } else {
 378                         if (!argp->reclaim) {
 379                                 /* We appear to be out of the grace period */
 380                                 wake_up_all(&host->h_gracewait);
 381                         }
 382                         dprintk("lockd: server returns status %d\n", resp->status);
 383                         return 0;       /* Okay, call complete */
 384                 }
 385
 386 in_grace_period:
 387                 /*
 388                  * The server has rebooted and appears to be in the grace
 389                  * period during which locks are only allowed to be
 390                  * reclaimed.
 391                  * We can only back off and try again later.
 392                  */
 393                 status = nlm_wait_on_grace(&host->h_gracewait);
 394         } while (status == 0);
 395
 396         return status;
 397 }
 398
 399 /*
 400  * Generic NLM call, async version.
 401  */
 402 int
 403 nlmsvc_async_call(struct nlm_rqst *req, u32 proc, rpc_action callback)
 404 {
 405         struct nlm_host *host = req->a_host;
 406         struct rpc_clnt *clnt;
 407         struct rpc_message msg = {
 408                 .rpc_argp       = &req->a_args,
 409                 .rpc_resp       = &req->a_res,
 410         };
 411         int             status;
 412
 413         dprintk("lockd: call procedure %d on %s (async)\n",
 414                         (int)proc, host->h_name);
 415
 416         /* If we have no RPC client yet, create one. */
 417         if ((clnt = nlm_bind_host(host)) == NULL)
 418                 return -ENOLCK;
 419         msg.rpc_proc = &clnt->cl_procinfo[proc];
 420
 421         /* bootstrap and kick off the async RPC call */
 422         status = rpc_call_async(clnt, &msg, RPC_TASK_ASYNC, callback, req);
 423
 424         return status;
 425 }
 426
 427 static int
 428 nlmclnt_async_call(struct nlm_rqst *req, u32 proc, rpc_action callback)
 429 {
 430         struct nlm_host *host = req->a_host;
 431         struct rpc_clnt *clnt;
 432         struct nlm_args *argp = &req->a_args;
 433         struct nlm_res  *resp = &req->a_res;
 434         struct rpc_message msg = {
 435                 .rpc_argp       = argp,
 436                 .rpc_resp       = resp,
 437         };
 438         int             status;
 439
 440         dprintk("lockd: call procedure %d on %s (async)\n",
 441                         (int)proc, host->h_name);
 442
 443         /* If we have no RPC client yet, create one. */
 444         if ((clnt = nlm_bind_host(host)) == NULL)
 445                 return -ENOLCK;
 446         msg.rpc_proc = &clnt->cl_procinfo[proc];
 447
 448         /* Increment host refcount */
 449         nlm_get_host(host);
 450         /* bootstrap and kick off the async RPC call */
 451         status = rpc_call_async(clnt, &msg, RPC_TASK_ASYNC, callback, req);
 452         if (status < 0)
 453                 nlm_release_host(host);
 454         return status;
 455 }
 456
 457 /*
 458  * TEST for the presence of a conflicting lock
 459  */
 460 static int
 461 nlmclnt_test(struct nlm_rqst *req, struct file_lock *fl)
 462 {
 463         int     status;
 464
 465         status = nlmclnt_call(req, NLMPROC_TEST);
 466         nlmclnt_release_lockargs(req);
 467         if (status < 0)
 468                 return status;
 469
 470         status = req->a_res.status;
 471         if (status == NLM_LCK_GRANTED) {
 472                 fl->fl_type = F_UNLCK;
 473         } if (status == NLM_LCK_DENIED) {
 474                 /*
 475                  * Report the conflicting lock back to the application.
 476                  */
 477                 locks_copy_lock(fl, &req->a_res.lock.fl);
 478                 fl->fl_pid = 0;
 479         } else {
 480                 return nlm_stat_to_errno(req->a_res.status);
 481         }
 482
 483         return 0;
 484 }
 485
 486 static void nlmclnt_locks_copy_lock(struct file_lock *new, struct file_lock *fl)
 487 {
 488         memcpy(&new->fl_u.nfs_fl, &fl->fl_u.nfs_fl, sizeof(new->fl_u.nfs_fl));
 489         nlm_get_lockowner(new->fl_u.nfs_fl.owner);
 490 }
 491
 492 static void nlmclnt_locks_release_private(struct file_lock *fl)
 493 {
 494         nlm_put_lockowner(fl->fl_u.nfs_fl.owner);
 495         fl->fl_ops = NULL;
 496 }
 497
 498 static struct file_lock_operations nlmclnt_lock_ops = {
 499         .fl_copy_lock = nlmclnt_locks_copy_lock,
 500         .fl_release_private = nlmclnt_locks_release_private,
 501 };
 502
 503 static void nlmclnt_locks_init_private(struct file_lock *fl, struct nlm_host *host)
 504 {
 505         BUG_ON(fl->fl_ops != NULL);
 506         fl->fl_u.nfs_fl.state = 0;
 507         fl->fl_u.nfs_fl.flags = 0;
 508         fl->fl_u.nfs_fl.owner = nlm_find_lockowner(host, fl->fl_owner);
 509         fl->fl_ops = &nlmclnt_lock_ops;
 510 }
 511
 512 static void do_vfs_lock(struct file_lock *fl)
 513 {
 514         int res = 0;
 515         switch (fl->fl_flags & (FL_POSIX|FL_FLOCK)) {
 516                 case FL_POSIX:
 517                         res = posix_lock_file_wait(fl->fl_file, fl);
 518                         break;
 519                 case FL_FLOCK:
 520                         res = flock_lock_file_wait(fl->fl_file, fl);
 521                         break;
 522                 default:
 523                         BUG();
 524         }
 525         if (res < 0)
 526                 printk(KERN_WARNING "%s: VFS is out of sync with lock manager!\n",
 527                                 __FUNCTION__);
 528 }
 529
 530 /*
 531  * LOCK: Try to create a lock
 532  *
 533  *                      Programmer Harassment Alert
 534  *
 535  * When given a blocking lock request in a sync RPC call, the HPUX lockd
 536  * will faithfully return LCK_BLOCKED but never cares to notify us when
 537  * the lock could be granted. This way, our local process could hang
 538  * around forever waiting for the callback.
 539  *
 540  *  Solution A: Implement busy-waiting
 541  *  Solution B: Use the async version of the call (NLM_LOCK_{MSG,RES})
 542  *
 543  * For now I am implementing solution A, because I hate the idea of
 544  * re-implementing lockd for a third time in two months. The async
 545  * calls shouldn't be too hard to do, however.
 546  *
 547  * This is one of the lovely things about standards in the NFS area:
 548  * they're so soft and squishy you can't really blame HP for doing this.
 549  */
 550 static int
 551 nlmclnt_lock(struct nlm_rqst *req, struct file_lock *fl)
 552 {
 553         struct nlm_host *host = req->a_host;
 554         struct nlm_res  *resp = &req->a_res;
 555         long timeout;
 556         int status;
 557
 558         if (!host->h_monitored && nsm_monitor(host) < 0) {
 559                 printk(KERN_NOTICE "lockd: failed to monitor %s\n",
 560                                         host->h_name);
 561                 status = -ENOLCK;
 562                 goto out;
 563         }
 564
 565         if (req->a_args.block) {
 566                 status = nlmclnt_prepare_block(req, host, fl);
 567                 if (status < 0)
 568                         goto out;
 569         }
 570         for(;;) {
 571                 status = nlmclnt_call(req, NLMPROC_LOCK);
 572                 if (status < 0)
 573                         goto out_unblock;
 574                 if (resp->status != NLM_LCK_BLOCKED)
 575                         break;
 576                 /* Wait on an NLM blocking lock */
 577                 timeout = nlmclnt_block(req, NLMCLNT_POLL_TIMEOUT);
 578                 /* Did a reclaimer thread notify us of a server reboot? */
 579                 if (resp->status ==  NLM_LCK_DENIED_GRACE_PERIOD)
 580                         continue;
 581                 if (resp->status != NLM_LCK_BLOCKED)
 582                         break;
 583                 if (timeout >= 0)
 584                         continue;
 585                 /* We were interrupted. Send a CANCEL request to the server
 586                  * and exit
 587                  */
 588                 status = (int)timeout;
 589                 goto out_unblock;
 590         }
 591
 592         if (resp->status == NLM_LCK_GRANTED) {
 593                 fl->fl_u.nfs_fl.state = host->h_state;
 594                 fl->fl_u.nfs_fl.flags |= NFS_LCK_GRANTED;
 595                 fl->fl_flags |= FL_SLEEP;
 596                 do_vfs_lock(fl);
 597         }
 598         status = nlm_stat_to_errno(resp->status);
 599 out_unblock:
 600         nlmclnt_finish_block(req);
 601         /* Cancel the blocked request if it is still pending */
 602         if (resp->status == NLM_LCK_BLOCKED)
 603                 nlmclnt_cancel(host, fl);
 604 out:
 605         nlmclnt_release_lockargs(req);
 606         return status;
 607 }
 608
 609 /*
 610  * RECLAIM: Try to reclaim a lock
 611  */
 612 int
 613 nlmclnt_reclaim(struct nlm_host *host, struct file_lock *fl)
 614 {
 615         struct nlm_rqst reqst, *req;
 616         int             status;
 617
 618         req = &reqst;
 619         memset(req, 0, sizeof(*req));
 620         locks_init_lock(&req->a_args.lock.fl);
 621         locks_init_lock(&req->a_res.lock.fl);
 622         req->a_host  = host;
 623         req->a_flags = 0;
 624
 625         /* Set up the argument struct */
 626         nlmclnt_setlockargs(req, fl);
 627         req->a_args.reclaim = 1;
 628
 629         if ((status = nlmclnt_call(req, NLMPROC_LOCK)) >= 0
 630          && req->a_res.status == NLM_LCK_GRANTED)
 631                 return 0;
 632
 633         printk(KERN_WARNING "lockd: failed to reclaim lock for pid %d "
 634                                 "(errno %d, status %d)\n", fl->fl_pid,
 635                                 status, req->a_res.status);
 636
 637         /*
 638          * FIXME: This is a serious failure. We can
 639          *
 640          *  a.  Ignore the problem
 641          *  b.  Send the owning process some signal (Linux doesn't have
 642          *      SIGLOST, though...)
 643          *  c.  Retry the operation
 644          *
 645          * Until someone comes up with a simple implementation
 646          * for b or c, I'll choose option a.
 647          */
 648
 649         return -ENOLCK;
 650 }
 651
 652 /*
 653  * UNLOCK: remove an existing lock
 654  */
 655 static int
 656 nlmclnt_unlock(struct nlm_rqst *req, struct file_lock *fl)
 657 {
 658         struct nlm_res  *resp = &req->a_res;
 659         int             status;
 660
 661         /* Clean the GRANTED flag now so the lock doesn't get
 662          * reclaimed while we're stuck in the unlock call. */
 663         fl->fl_u.nfs_fl.flags &= ~NFS_LCK_GRANTED;
 664
 665         if (req->a_flags & RPC_TASK_ASYNC) {
 666                 status = nlmclnt_async_call(req, NLMPROC_UNLOCK,
 667                                         nlmclnt_unlock_callback);
 668                 /* Hrmf... Do the unlock early since locks_remove_posix()
 669                  * really expects us to free the lock synchronously */
 670                 do_vfs_lock(fl);
 671                 if (status < 0) {
 672                         nlmclnt_release_lockargs(req);
 673                         kfree(req);
 674                 }
 675                 return status;
 676         }
 677
 678         status = nlmclnt_call(req, NLMPROC_UNLOCK);
 679         nlmclnt_release_lockargs(req);
 680         if (status < 0)
 681                 return status;
 682
 683         do_vfs_lock(fl);
 684         if (resp->status == NLM_LCK_GRANTED)
 685                 return 0;
 686
 687         if (resp->status != NLM_LCK_DENIED_NOLOCKS)
 688                 printk("lockd: unexpected unlock status: %d\n", resp->status);
 689
 690         /* What to do now? I'm out of my depth... */
 691
 692         return -ENOLCK;
 693 }
 694
 695 static void
 696 nlmclnt_unlock_callback(struct rpc_task *task)
 697 {
 698         struct nlm_rqst *req = (struct nlm_rqst *) task->tk_calldata;
 699         int             status = req->a_res.status;
 700
 701         if (RPC_ASSASSINATED(task))
 702                 goto die;
 703
 704         if (task->tk_status < 0) {
 705                 dprintk("lockd: unlock failed (err = %d)\n", -task->tk_status);
 706                 goto retry_rebind;
 707         }
 708         if (status == NLM_LCK_DENIED_GRACE_PERIOD) {
 709                 rpc_delay(task, NLMCLNT_GRACE_WAIT);
 710                 goto retry_unlock;
 711         }
 712         if (status != NLM_LCK_GRANTED)
 713                 printk(KERN_WARNING "lockd: unexpected unlock status: %d\n", status);
 714 die:
 715         nlm_release_host(req->a_host);
 716         nlmclnt_release_lockargs(req);
 717         kfree(req);
 718         return;
 719  retry_rebind:
 720         nlm_rebind_host(req->a_host);
 721  retry_unlock:
 722         rpc_restart_call(task);
 723 }
 724
 725 /*
 726  * Cancel a blocked lock request.
 727  * We always use an async RPC call for this in order not to hang a
 728  * process that has been Ctrl-C'ed.
 729  */
 730 int
 731 nlmclnt_cancel(struct nlm_host *host, struct file_lock *fl)
 732 {
 733         struct nlm_rqst *req;
 734         unsigned long   flags;
 735         sigset_t        oldset;
 736         int             status;
 737
 738         /* Block all signals while setting up call */
 739         spin_lock_irqsave(&current->sighand->siglock, flags);
 740         oldset = current->blocked;
 741         sigfillset(&current->blocked);
 742         recalc_sigpending();
 743         spin_unlock_irqrestore(&current->sighand->siglock, flags);
 744
 745         req = nlmclnt_alloc_call();
 746         if (!req)
 747                 return -ENOMEM;
 748         req->a_host  = host;
 749         req->a_flags = RPC_TASK_ASYNC;
 750
 751         nlmclnt_setlockargs(req, fl);
 752
 753         status = nlmclnt_async_call(req, NLMPROC_CANCEL,
 754                                         nlmclnt_cancel_callback);
 755         if (status < 0) {
 756                 nlmclnt_release_lockargs(req);
 757                 kfree(req);
 758         }
 759
 760         spin_lock_irqsave(&current->sighand->siglock, flags);
 761         current->blocked = oldset;
 762         recalc_sigpending();
 763         spin_unlock_irqrestore(&current->sighand->siglock, flags);
 764
 765         return status;
 766 }
 767
 768 static void
 769 nlmclnt_cancel_callback(struct rpc_task *task)
 770 {
 771         struct nlm_rqst *req = (struct nlm_rqst *) task->tk_calldata;
 772
 773         if (RPC_ASSASSINATED(task))
 774                 goto die;
 775
 776         if (task->tk_status < 0) {
 777                 dprintk("lockd: CANCEL call error %d, retrying.\n",
 778                                         task->tk_status);
 779                 goto retry_cancel;
 780         }
 781
 782         dprintk("lockd: cancel status %d (task %d)\n",
 783                         req->a_res.status, task->tk_pid);
 784
 785         switch (req->a_res.status) {
 786         case NLM_LCK_GRANTED:
 787         case NLM_LCK_DENIED_GRACE_PERIOD:
 788                 /* Everything's good */
 789                 break;
 790         case NLM_LCK_DENIED_NOLOCKS:
 791                 dprintk("lockd: CANCEL failed (server has no locks)\n");
 792                 goto retry_cancel;
 793         default:
 794                 printk(KERN_NOTICE "lockd: weird return %d for CANCEL call\n",
 795                         req->a_res.status);
 796         }
 797
 798 die:
 799         nlm_release_host(req->a_host);
 800         nlmclnt_release_lockargs(req);
 801         kfree(req);
 802         return;
 803
 804 retry_cancel:
 805         nlm_rebind_host(req->a_host);
 806         rpc_restart_call(task);
 807         rpc_delay(task, 30 * HZ);
 808 }
 809
 810 /*
 811  * Convert an NLM status code to a generic kernel errno
 812  */
 813 static int
 814 nlm_stat_to_errno(u32 status)
 815 {
 816         switch(status) {
 817         case NLM_LCK_GRANTED:
 818                 return 0;
 819         case NLM_LCK_DENIED:
 820                 return -EAGAIN;
 821         case NLM_LCK_DENIED_NOLOCKS:
 822         case NLM_LCK_DENIED_GRACE_PERIOD:
 823                 return -ENOLCK;
 824         case NLM_LCK_BLOCKED:
 825                 printk(KERN_NOTICE "lockd: unexpected status NLM_BLOCKED\n");
 826                 return -ENOLCK;
 827 #ifdef CONFIG_LOCKD_V4
 828         case NLM_DEADLCK:
 829                 return -EDEADLK;
 830         case NLM_ROFS:
 831                 return -EROFS;
 832         case NLM_STALE_FH:
 833                 return -ESTALE;
 834         case NLM_FBIG:
 835                 return -EOVERFLOW;
 836         case NLM_FAILED:
 837                 return -ENOLCK;
 838 #endif
 839         }
 840         printk(KERN_NOTICE "lockd: unexpected server status %d\n", status);
 841         return -ENOLCK;
 842 }