git.oblomov.eu 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
  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         if (new != NULL)
 116                 kfree(new);
 117         return res;
 118 }
 119
 120 /*
 121  * Initialize arguments for TEST/LOCK/UNLOCK/CANCEL calls
 122  */
 123 static void nlmclnt_setlockargs(struct nlm_rqst *req, struct file_lock *fl)
 124 {
 125         struct nlm_args *argp = &req->a_args;
 126         struct nlm_lock *lock = &argp->lock;
 127
 128         nlmclnt_next_cookie(&argp->cookie);
 129         argp->state   = nsm_local_state;
 130         memcpy(&lock->fh, NFS_FH(fl->fl_file->f_dentry->d_inode), sizeof(struct nfs_fh));
 131         lock->caller  = system_utsname.nodename;
 132         lock->oh.data = req->a_owner;
 133         lock->oh.len  = sprintf(req->a_owner, "%d@%s",
 134                                 current->pid, system_utsname.nodename);
 135         locks_copy_lock(&lock->fl, fl);
 136 }
 137
 138 static void nlmclnt_release_lockargs(struct nlm_rqst *req)
 139 {
 140         struct file_lock *fl = &req->a_args.lock.fl;
 141
 142         if (fl->fl_ops && fl->fl_ops->fl_release_private)
 143                 fl->fl_ops->fl_release_private(fl);
 144 }
 145
 146 /*
 147  * Initialize arguments for GRANTED call. The nlm_rqst structure
 148  * has been cleared already.
 149  */
 150 int
 151 nlmclnt_setgrantargs(struct nlm_rqst *call, struct nlm_lock *lock)
 152 {
 153         locks_copy_lock(&call->a_args.lock.fl, &lock->fl);
 154         memcpy(&call->a_args.lock.fh, &lock->fh, sizeof(call->a_args.lock.fh));
 155         call->a_args.lock.caller = system_utsname.nodename;
 156         call->a_args.lock.oh.len = lock->oh.len;
 157
 158         /* set default data area */
 159         call->a_args.lock.oh.data = call->a_owner;
 160
 161         if (lock->oh.len > NLMCLNT_OHSIZE) {
 162                 void *data = kmalloc(lock->oh.len, GFP_KERNEL);
 163                 if (!data) {
 164                         nlmclnt_freegrantargs(call);
 165                         return 0;
 166                 }
 167                 call->a_args.lock.oh.data = (u8 *) data;
 168         }
 169
 170         memcpy(call->a_args.lock.oh.data, lock->oh.data, lock->oh.len);
 171         return 1;
 172 }
 173
 174 void
 175 nlmclnt_freegrantargs(struct nlm_rqst *call)
 176 {
 177         struct file_lock *fl = &call->a_args.lock.fl;
 178         /*
 179          * Check whether we allocated memory for the owner.
 180          */
 181         if (call->a_args.lock.oh.data != (u8 *) call->a_owner) {
 182                 kfree(call->a_args.lock.oh.data);
 183         }
 184         if (fl->fl_ops && fl->fl_ops->fl_release_private)
 185                 fl->fl_ops->fl_release_private(fl);
 186 }
 187
 188 /*
 189  * This is the main entry point for the NLM client.
 190  */
 191 int
 192 nlmclnt_proc(struct inode *inode, int cmd, struct file_lock *fl)
 193 {
 194         struct nfs_server       *nfssrv = NFS_SERVER(inode);
 195         struct nlm_host         *host;
 196         struct nlm_rqst         reqst, *call = &reqst;
 197         sigset_t                oldset;
 198         unsigned long           flags;
 199         int                     status, proto, vers;
 200
 201         vers = (NFS_PROTO(inode)->version == 3) ? 4 : 1;
 202         if (NFS_PROTO(inode)->version > 3) {
 203                 printk(KERN_NOTICE "NFSv4 file locking not implemented!\n");
 204                 return -ENOLCK;
 205         }
 206
 207         /* Retrieve transport protocol from NFS client */
 208         proto = NFS_CLIENT(inode)->cl_xprt->prot;
 209
 210         if (!(host = nlmclnt_lookup_host(NFS_ADDR(inode), proto, vers)))
 211                 return -ENOLCK;
 212
 213         /* Create RPC client handle if not there, and copy soft
 214          * and intr flags from NFS client. */
 215         if (host->h_rpcclnt == NULL) {
 216                 struct rpc_clnt *clnt;
 217
 218                 /* Bind an rpc client to this host handle (does not
 219                  * perform a portmapper lookup) */
 220                 if (!(clnt = nlm_bind_host(host))) {
 221                         status = -ENOLCK;
 222                         goto done;
 223                 }
 224                 clnt->cl_softrtry = nfssrv->client->cl_softrtry;
 225                 clnt->cl_intr     = nfssrv->client->cl_intr;
 226                 clnt->cl_chatty   = nfssrv->client->cl_chatty;
 227         }
 228
 229         /* Keep the old signal mask */
 230         spin_lock_irqsave(&current->sighand->siglock, flags);
 231         oldset = current->blocked;
 232
 233         /* If we're cleaning up locks because the process is exiting,
 234          * perform the RPC call asynchronously. */
 235         if ((IS_SETLK(cmd) || IS_SETLKW(cmd))
 236             && fl->fl_type == F_UNLCK
 237             && (current->flags & PF_EXITING)) {
 238                 sigfillset(&current->blocked);  /* Mask all signals */
 239                 recalc_sigpending();
 240                 spin_unlock_irqrestore(&current->sighand->siglock, flags);
 241
 242                 call = nlmclnt_alloc_call();
 243                 if (!call) {
 244                         status = -ENOMEM;
 245                         goto out_restore;
 246                 }
 247                 call->a_flags = RPC_TASK_ASYNC;
 248         } else {
 249                 spin_unlock_irqrestore(&current->sighand->siglock, flags);
 250                 memset(call, 0, sizeof(*call));
 251                 locks_init_lock(&call->a_args.lock.fl);
 252                 locks_init_lock(&call->a_res.lock.fl);
 253         }
 254         call->a_host = host;
 255
 256         nlmclnt_locks_init_private(fl, host);
 257
 258         /* Set up the argument struct */
 259         nlmclnt_setlockargs(call, fl);
 260
 261         if (IS_SETLK(cmd) || IS_SETLKW(cmd)) {
 262                 if (fl->fl_type != F_UNLCK) {
 263                         call->a_args.block = IS_SETLKW(cmd) ? 1 : 0;
 264                         status = nlmclnt_lock(call, fl);
 265                 } else
 266                         status = nlmclnt_unlock(call, fl);
 267         } else if (IS_GETLK(cmd))
 268                 status = nlmclnt_test(call, fl);
 269         else
 270                 status = -EINVAL;
 271
 272  out_restore:
 273         spin_lock_irqsave(&current->sighand->siglock, flags);
 274         current->blocked = oldset;
 275         recalc_sigpending();
 276         spin_unlock_irqrestore(&current->sighand->siglock, flags);
 277
 278 done:
 279         dprintk("lockd: clnt proc returns %d\n", status);
 280         nlm_release_host(host);
 281         return status;
 282 }
 283 EXPORT_SYMBOL(nlmclnt_proc);
 284
 285 /*
 286  * Allocate an NLM RPC call struct
 287  */
 288 struct nlm_rqst *
 289 nlmclnt_alloc_call(void)
 290 {
 291         struct nlm_rqst *call;
 292
 293         while (!signalled()) {
 294                 call = (struct nlm_rqst *) kmalloc(sizeof(struct nlm_rqst), GFP_KERNEL);
 295                 if (call) {
 296                         memset(call, 0, sizeof(*call));
 297                         locks_init_lock(&call->a_args.lock.fl);
 298                         locks_init_lock(&call->a_res.lock.fl);
 299                         return call;
 300                 }
 301                 printk("nlmclnt_alloc_call: failed, waiting for memory\n");
 302                 schedule_timeout_interruptible(5*HZ);
 303         }
 304         return NULL;
 305 }
 306
 307 static int nlm_wait_on_grace(wait_queue_head_t *queue)
 308 {
 309         DEFINE_WAIT(wait);
 310         int status = -EINTR;
 311
 312         prepare_to_wait(queue, &wait, TASK_INTERRUPTIBLE);
 313         if (!signalled ()) {
 314                 schedule_timeout(NLMCLNT_GRACE_WAIT);
 315                 try_to_freeze();
 316                 if (!signalled ())
 317                         status = 0;
 318         }
 319         finish_wait(queue, &wait);
 320         return status;
 321 }
 322
 323 /*
 324  * Generic NLM call
 325  */
 326 static int
 327 nlmclnt_call(struct nlm_rqst *req, u32 proc)
 328 {
 329         struct nlm_host *host = req->a_host;
 330         struct rpc_clnt *clnt;
 331         struct nlm_args *argp = &req->a_args;
 332         struct nlm_res  *resp = &req->a_res;
 333         struct rpc_message msg = {
 334                 .rpc_argp       = argp,
 335                 .rpc_resp       = resp,
 336         };
 337         int             status;
 338
 339         dprintk("lockd: call procedure %d on %s\n",
 340                         (int)proc, host->h_name);
 341
 342         do {
 343                 if (host->h_reclaiming && !argp->reclaim)
 344                         goto in_grace_period;
 345
 346                 /* If we have no RPC client yet, create one. */
 347                 if ((clnt = nlm_bind_host(host)) == NULL)
 348                         return -ENOLCK;
 349                 msg.rpc_proc = &clnt->cl_procinfo[proc];
 350
 351                 /* Perform the RPC call. If an error occurs, try again */
 352                 if ((status = rpc_call_sync(clnt, &msg, 0)) < 0) {
 353                         dprintk("lockd: rpc_call returned error %d\n", -status);
 354                         switch (status) {
 355                         case -EPROTONOSUPPORT:
 356                                 status = -EINVAL;
 357                                 break;
 358                         case -ECONNREFUSED:
 359                         case -ETIMEDOUT:
 360                         case -ENOTCONN:
 361                                 nlm_rebind_host(host);
 362                                 status = -EAGAIN;
 363                                 break;
 364                         case -ERESTARTSYS:
 365                                 return signalled () ? -EINTR : status;
 366                         default:
 367                                 break;
 368                         }
 369                         break;
 370                 } else
 371                 if (resp->status == NLM_LCK_DENIED_GRACE_PERIOD) {
 372                         dprintk("lockd: server in grace period\n");
 373                         if (argp->reclaim) {
 374                                 printk(KERN_WARNING
 375                                      "lockd: spurious grace period reject?!\n");
 376                                 return -ENOLCK;
 377                         }
 378                 } else {
 379                         if (!argp->reclaim) {
 380                                 /* We appear to be out of the grace period */
 381                                 wake_up_all(&host->h_gracewait);
 382                         }
 383                         dprintk("lockd: server returns status %d\n", resp->status);
 384                         return 0;       /* Okay, call complete */
 385                 }
 386
 387 in_grace_period:
 388                 /*
 389                  * The server has rebooted and appears to be in the grace
 390                  * period during which locks are only allowed to be
 391                  * reclaimed.
 392                  * We can only back off and try again later.
 393                  */
 394                 status = nlm_wait_on_grace(&host->h_gracewait);
 395         } while (status == 0);
 396
 397         return status;
 398 }
 399
 400 /*
 401  * Generic NLM call, async version.
 402  */
 403 int
 404 nlmsvc_async_call(struct nlm_rqst *req, u32 proc, rpc_action callback)
 405 {
 406         struct nlm_host *host = req->a_host;
 407         struct rpc_clnt *clnt;
 408         struct rpc_message msg = {
 409                 .rpc_argp       = &req->a_args,
 410                 .rpc_resp       = &req->a_res,
 411         };
 412         int             status;
 413
 414         dprintk("lockd: call procedure %d on %s (async)\n",
 415                         (int)proc, host->h_name);
 416
 417         /* If we have no RPC client yet, create one. */
 418         if ((clnt = nlm_bind_host(host)) == NULL)
 419                 return -ENOLCK;
 420         msg.rpc_proc = &clnt->cl_procinfo[proc];
 421
 422         /* bootstrap and kick off the async RPC call */
 423         status = rpc_call_async(clnt, &msg, RPC_TASK_ASYNC, callback, req);
 424
 425         return status;
 426 }
 427
 428 static int
 429 nlmclnt_async_call(struct nlm_rqst *req, u32 proc, rpc_action callback)
 430 {
 431         struct nlm_host *host = req->a_host;
 432         struct rpc_clnt *clnt;
 433         struct nlm_args *argp = &req->a_args;
 434         struct nlm_res  *resp = &req->a_res;
 435         struct rpc_message msg = {
 436                 .rpc_argp       = argp,
 437                 .rpc_resp       = resp,
 438         };
 439         int             status;
 440
 441         dprintk("lockd: call procedure %d on %s (async)\n",
 442                         (int)proc, host->h_name);
 443
 444         /* If we have no RPC client yet, create one. */
 445         if ((clnt = nlm_bind_host(host)) == NULL)
 446                 return -ENOLCK;
 447         msg.rpc_proc = &clnt->cl_procinfo[proc];
 448
 449         /* Increment host refcount */
 450         nlm_get_host(host);
 451         /* bootstrap and kick off the async RPC call */
 452         status = rpc_call_async(clnt, &msg, RPC_TASK_ASYNC, callback, req);
 453         if (status < 0)
 454                 nlm_release_host(host);
 455         return status;
 456 }
 457
 458 /*
 459  * TEST for the presence of a conflicting lock
 460  */
 461 static int
 462 nlmclnt_test(struct nlm_rqst *req, struct file_lock *fl)
 463 {
 464         int     status;
 465
 466         status = nlmclnt_call(req, NLMPROC_TEST);
 467         nlmclnt_release_lockargs(req);
 468         if (status < 0)
 469                 return status;
 470
 471         status = req->a_res.status;
 472         if (status == NLM_LCK_GRANTED) {
 473                 fl->fl_type = F_UNLCK;
 474         } if (status == NLM_LCK_DENIED) {
 475                 /*
 476                  * Report the conflicting lock back to the application.
 477                  */
 478                 locks_copy_lock(fl, &req->a_res.lock.fl);
 479                 fl->fl_pid = 0;
 480         } else {
 481                 return nlm_stat_to_errno(req->a_res.status);
 482         }
 483
 484         return 0;
 485 }
 486
 487 static void nlmclnt_locks_copy_lock(struct file_lock *new, struct file_lock *fl)
 488 {
 489         memcpy(&new->fl_u.nfs_fl, &fl->fl_u.nfs_fl, sizeof(new->fl_u.nfs_fl));
 490         nlm_get_lockowner(new->fl_u.nfs_fl.owner);
 491 }
 492
 493 static void nlmclnt_locks_release_private(struct file_lock *fl)
 494 {
 495         nlm_put_lockowner(fl->fl_u.nfs_fl.owner);
 496         fl->fl_ops = NULL;
 497 }
 498
 499 static struct file_lock_operations nlmclnt_lock_ops = {
 500         .fl_copy_lock = nlmclnt_locks_copy_lock,
 501         .fl_release_private = nlmclnt_locks_release_private,
 502 };
 503
 504 static void nlmclnt_locks_init_private(struct file_lock *fl, struct nlm_host *host)
 505 {
 506         BUG_ON(fl->fl_ops != NULL);
 507         fl->fl_u.nfs_fl.state = 0;
 508         fl->fl_u.nfs_fl.flags = 0;
 509         fl->fl_u.nfs_fl.owner = nlm_find_lockowner(host, fl->fl_owner);
 510         fl->fl_ops = &nlmclnt_lock_ops;
 511 }
 512
 513 static void do_vfs_lock(struct file_lock *fl)
 514 {
 515         int res = 0;
 516         switch (fl->fl_flags & (FL_POSIX|FL_FLOCK)) {
 517                 case FL_POSIX:
 518                         res = posix_lock_file_wait(fl->fl_file, fl);
 519                         break;
 520                 case FL_FLOCK:
 521                         res = flock_lock_file_wait(fl->fl_file, fl);
 522                         break;
 523                 default:
 524                         BUG();
 525         }
 526         if (res < 0)
 527                 printk(KERN_WARNING "%s: VFS is out of sync with lock manager!\n",
 528                                 __FUNCTION__);
 529 }
 530
 531 /*
 532  * LOCK: Try to create a lock
 533  *
 534  *                      Programmer Harassment Alert
 535  *
 536  * When given a blocking lock request in a sync RPC call, the HPUX lockd
 537  * will faithfully return LCK_BLOCKED but never cares to notify us when
 538  * the lock could be granted. This way, our local process could hang
 539  * around forever waiting for the callback.
 540  *
 541  *  Solution A: Implement busy-waiting
 542  *  Solution B: Use the async version of the call (NLM_LOCK_{MSG,RES})
 543  *
 544  * For now I am implementing solution A, because I hate the idea of
 545  * re-implementing lockd for a third time in two months. The async
 546  * calls shouldn't be too hard to do, however.
 547  *
 548  * This is one of the lovely things about standards in the NFS area:
 549  * they're so soft and squishy you can't really blame HP for doing this.
 550  */
 551 static int
 552 nlmclnt_lock(struct nlm_rqst *req, struct file_lock *fl)
 553 {
 554         struct nlm_host *host = req->a_host;
 555         struct nlm_res  *resp = &req->a_res;
 556         long timeout;
 557         int status;
 558
 559         if (!host->h_monitored && nsm_monitor(host) < 0) {
 560                 printk(KERN_NOTICE "lockd: failed to monitor %s\n",
 561                                         host->h_name);
 562                 status = -ENOLCK;
 563                 goto out;
 564         }
 565
 566         if (req->a_args.block) {
 567                 status = nlmclnt_prepare_block(req, host, fl);
 568                 if (status < 0)
 569                         goto out;
 570         }
 571         for(;;) {
 572                 status = nlmclnt_call(req, NLMPROC_LOCK);
 573                 if (status < 0)
 574                         goto out_unblock;
 575                 if (resp->status != NLM_LCK_BLOCKED)
 576                         break;
 577                 /* Wait on an NLM blocking lock */
 578                 timeout = nlmclnt_block(req, NLMCLNT_POLL_TIMEOUT);
 579                 /* Did a reclaimer thread notify us of a server reboot? */
 580                 if (resp->status ==  NLM_LCK_DENIED_GRACE_PERIOD)
 581                         continue;
 582                 if (resp->status != NLM_LCK_BLOCKED)
 583                         break;
 584                 if (timeout >= 0)
 585                         continue;
 586                 /* We were interrupted. Send a CANCEL request to the server
 587                  * and exit
 588                  */
 589                 status = (int)timeout;
 590                 goto out_unblock;
 591         }
 592
 593         if (resp->status == NLM_LCK_GRANTED) {
 594                 fl->fl_u.nfs_fl.state = host->h_state;
 595                 fl->fl_u.nfs_fl.flags |= NFS_LCK_GRANTED;
 596                 fl->fl_flags |= FL_SLEEP;
 597                 do_vfs_lock(fl);
 598         }
 599         status = nlm_stat_to_errno(resp->status);
 600 out_unblock:
 601         nlmclnt_finish_block(req);
 602         /* Cancel the blocked request if it is still pending */
 603         if (resp->status == NLM_LCK_BLOCKED)
 604                 nlmclnt_cancel(host, fl);
 605 out:
 606         nlmclnt_release_lockargs(req);
 607         return status;
 608 }
 609
 610 /*
 611  * RECLAIM: Try to reclaim a lock
 612  */
 613 int
 614 nlmclnt_reclaim(struct nlm_host *host, struct file_lock *fl)
 615 {
 616         struct nlm_rqst reqst, *req;
 617         int             status;
 618
 619         req = &reqst;
 620         memset(req, 0, sizeof(*req));
 621         locks_init_lock(&req->a_args.lock.fl);
 622         locks_init_lock(&req->a_res.lock.fl);
 623         req->a_host  = host;
 624         req->a_flags = 0;
 625
 626         /* Set up the argument struct */
 627         nlmclnt_setlockargs(req, fl);
 628         req->a_args.reclaim = 1;
 629
 630         if ((status = nlmclnt_call(req, NLMPROC_LOCK)) >= 0
 631          && req->a_res.status == NLM_LCK_GRANTED)
 632                 return 0;
 633
 634         printk(KERN_WARNING "lockd: failed to reclaim lock for pid %d "
 635                                 "(errno %d, status %d)\n", fl->fl_pid,
 636                                 status, req->a_res.status);
 637
 638         /*
 639          * FIXME: This is a serious failure. We can
 640          *
 641          *  a.  Ignore the problem
 642          *  b.  Send the owning process some signal (Linux doesn't have
 643          *      SIGLOST, though...)
 644          *  c.  Retry the operation
 645          *
 646          * Until someone comes up with a simple implementation
 647          * for b or c, I'll choose option a.
 648          */
 649
 650         return -ENOLCK;
 651 }
 652
 653 /*
 654  * UNLOCK: remove an existing lock
 655  */
 656 static int
 657 nlmclnt_unlock(struct nlm_rqst *req, struct file_lock *fl)
 658 {
 659         struct nlm_res  *resp = &req->a_res;
 660         int             status;
 661
 662         /* Clean the GRANTED flag now so the lock doesn't get
 663          * reclaimed while we're stuck in the unlock call. */
 664         fl->fl_u.nfs_fl.flags &= ~NFS_LCK_GRANTED;
 665
 666         if (req->a_flags & RPC_TASK_ASYNC) {
 667                 status = nlmclnt_async_call(req, NLMPROC_UNLOCK,
 668                                         nlmclnt_unlock_callback);
 669                 /* Hrmf... Do the unlock early since locks_remove_posix()
 670                  * really expects us to free the lock synchronously */
 671                 do_vfs_lock(fl);
 672                 if (status < 0) {
 673                         nlmclnt_release_lockargs(req);
 674                         kfree(req);
 675                 }
 676                 return status;
 677         }
 678
 679         status = nlmclnt_call(req, NLMPROC_UNLOCK);
 680         nlmclnt_release_lockargs(req);
 681         if (status < 0)
 682                 return status;
 683
 684         do_vfs_lock(fl);
 685         if (resp->status == NLM_LCK_GRANTED)
 686                 return 0;
 687
 688         if (resp->status != NLM_LCK_DENIED_NOLOCKS)
 689                 printk("lockd: unexpected unlock status: %d\n", resp->status);
 690
 691         /* What to do now? I'm out of my depth... */
 692
 693         return -ENOLCK;
 694 }
 695
 696 static void
 697 nlmclnt_unlock_callback(struct rpc_task *task)
 698 {
 699         struct nlm_rqst *req = (struct nlm_rqst *) task->tk_calldata;
 700         int             status = req->a_res.status;
 701
 702         if (RPC_ASSASSINATED(task))
 703                 goto die;
 704
 705         if (task->tk_status < 0) {
 706                 dprintk("lockd: unlock failed (err = %d)\n", -task->tk_status);
 707                 goto retry_rebind;
 708         }
 709         if (status == NLM_LCK_DENIED_GRACE_PERIOD) {
 710                 rpc_delay(task, NLMCLNT_GRACE_WAIT);
 711                 goto retry_unlock;
 712         }
 713         if (status != NLM_LCK_GRANTED)
 714                 printk(KERN_WARNING "lockd: unexpected unlock status: %d\n", status);
 715 die:
 716         nlm_release_host(req->a_host);
 717         nlmclnt_release_lockargs(req);
 718         kfree(req);
 719         return;
 720  retry_rebind:
 721         nlm_rebind_host(req->a_host);
 722  retry_unlock:
 723         rpc_restart_call(task);
 724 }
 725
 726 /*
 727  * Cancel a blocked lock request.
 728  * We always use an async RPC call for this in order not to hang a
 729  * process that has been Ctrl-C'ed.
 730  */
 731 int
 732 nlmclnt_cancel(struct nlm_host *host, struct file_lock *fl)
 733 {
 734         struct nlm_rqst *req;
 735         unsigned long   flags;
 736         sigset_t        oldset;
 737         int             status;
 738
 739         /* Block all signals while setting up call */
 740         spin_lock_irqsave(&current->sighand->siglock, flags);
 741         oldset = current->blocked;
 742         sigfillset(&current->blocked);
 743         recalc_sigpending();
 744         spin_unlock_irqrestore(&current->sighand->siglock, flags);
 745
 746         req = nlmclnt_alloc_call();
 747         if (!req)
 748                 return -ENOMEM;
 749         req->a_host  = host;
 750         req->a_flags = RPC_TASK_ASYNC;
 751
 752         nlmclnt_setlockargs(req, fl);
 753
 754         status = nlmclnt_async_call(req, NLMPROC_CANCEL,
 755                                         nlmclnt_cancel_callback);
 756         if (status < 0) {
 757                 nlmclnt_release_lockargs(req);
 758                 kfree(req);
 759         }
 760
 761         spin_lock_irqsave(&current->sighand->siglock, flags);
 762         current->blocked = oldset;
 763         recalc_sigpending();
 764         spin_unlock_irqrestore(&current->sighand->siglock, flags);
 765
 766         return status;
 767 }
 768
 769 static void
 770 nlmclnt_cancel_callback(struct rpc_task *task)
 771 {
 772         struct nlm_rqst *req = (struct nlm_rqst *) task->tk_calldata;
 773
 774         if (RPC_ASSASSINATED(task))
 775                 goto die;
 776
 777         if (task->tk_status < 0) {
 778                 dprintk("lockd: CANCEL call error %d, retrying.\n",
 779                                         task->tk_status);
 780                 goto retry_cancel;
 781         }
 782
 783         dprintk("lockd: cancel status %d (task %d)\n",
 784                         req->a_res.status, task->tk_pid);
 785
 786         switch (req->a_res.status) {
 787         case NLM_LCK_GRANTED:
 788         case NLM_LCK_DENIED_GRACE_PERIOD:
 789                 /* Everything's good */
 790                 break;
 791         case NLM_LCK_DENIED_NOLOCKS:
 792                 dprintk("lockd: CANCEL failed (server has no locks)\n");
 793                 goto retry_cancel;
 794         default:
 795                 printk(KERN_NOTICE "lockd: weird return %d for CANCEL call\n",
 796                         req->a_res.status);
 797         }
 798
 799 die:
 800         nlm_release_host(req->a_host);
 801         nlmclnt_release_lockargs(req);
 802         kfree(req);
 803         return;
 804
 805 retry_cancel:
 806         nlm_rebind_host(req->a_host);
 807         rpc_restart_call(task);
 808         rpc_delay(task, 30 * HZ);
 809 }
 810
 811 /*
 812  * Convert an NLM status code to a generic kernel errno
 813  */
 814 static int
 815 nlm_stat_to_errno(u32 status)
 816 {
 817         switch(status) {
 818         case NLM_LCK_GRANTED:
 819                 return 0;
 820         case NLM_LCK_DENIED:
 821                 return -EAGAIN;
 822         case NLM_LCK_DENIED_NOLOCKS:
 823         case NLM_LCK_DENIED_GRACE_PERIOD:
 824                 return -ENOLCK;
 825         case NLM_LCK_BLOCKED:
 826                 printk(KERN_NOTICE "lockd: unexpected status NLM_BLOCKED\n");
 827                 return -ENOLCK;
 828 #ifdef CONFIG_LOCKD_V4
 829         case NLM_DEADLCK:
 830                 return -EDEADLK;
 831         case NLM_ROFS:
 832                 return -EROFS;
 833         case NLM_STALE_FH:
 834                 return -ESTALE;
 835         case NLM_FBIG:
 836                 return -EOVERFLOW;
 837         case NLM_FAILED:
 838                 return -ENOLCK;
 839 #endif
 840         }
 841         printk(KERN_NOTICE "lockd: unexpected server status %d\n", status);
 842         return -ENOLCK;
 843 }