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 #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  * Initialize arguments for GRANTED call. The nlm_rqst structure
 152  * has been cleared already.
 153  */
 154 int
 155 nlmclnt_setgrantargs(struct nlm_rqst *call, struct nlm_lock *lock)
 156 {
 157         locks_copy_lock(&call->a_args.lock.fl, &lock->fl);
 158         memcpy(&call->a_args.lock.fh, &lock->fh, sizeof(call->a_args.lock.fh));
 159         call->a_args.lock.caller = system_utsname.nodename;
 160         call->a_args.lock.oh.len = lock->oh.len;
 161
 162         /* set default data area */
 163         call->a_args.lock.oh.data = call->a_owner;
 164         call->a_args.lock.svid = lock->fl.fl_pid;
 165
 166         if (lock->oh.len > NLMCLNT_OHSIZE) {
 167                 void *data = kmalloc(lock->oh.len, GFP_KERNEL);
 168                 if (!data) {
 169                         nlmclnt_freegrantargs(call);
 170                         return 0;
 171                 }
 172                 call->a_args.lock.oh.data = (u8 *) data;
 173         }
 174
 175         memcpy(call->a_args.lock.oh.data, lock->oh.data, lock->oh.len);
 176         return 1;
 177 }
 178
 179 void
 180 nlmclnt_freegrantargs(struct nlm_rqst *call)
 181 {
 182         struct file_lock *fl = &call->a_args.lock.fl;
 183         /*
 184          * Check whether we allocated memory for the owner.
 185          */
 186         if (call->a_args.lock.oh.data != (u8 *) call->a_owner) {
 187                 kfree(call->a_args.lock.oh.data);
 188         }
 189         if (fl->fl_ops && fl->fl_ops->fl_release_private)
 190                 fl->fl_ops->fl_release_private(fl);
 191 }
 192
 193 /*
 194  * This is the main entry point for the NLM client.
 195  */
 196 int
 197 nlmclnt_proc(struct inode *inode, int cmd, struct file_lock *fl)
 198 {
 199         struct nfs_server       *nfssrv = NFS_SERVER(inode);
 200         struct nlm_host         *host;
 201         struct nlm_rqst         reqst, *call = &reqst;
 202         sigset_t                oldset;
 203         unsigned long           flags;
 204         int                     status, proto, vers;
 205
 206         vers = (NFS_PROTO(inode)->version == 3) ? 4 : 1;
 207         if (NFS_PROTO(inode)->version > 3) {
 208                 printk(KERN_NOTICE "NFSv4 file locking not implemented!\n");
 209                 return -ENOLCK;
 210         }
 211
 212         /* Retrieve transport protocol from NFS client */
 213         proto = NFS_CLIENT(inode)->cl_xprt->prot;
 214
 215         if (!(host = nlmclnt_lookup_host(NFS_ADDR(inode), proto, vers)))
 216                 return -ENOLCK;
 217
 218         /* Create RPC client handle if not there, and copy soft
 219          * and intr flags from NFS client. */
 220         if (host->h_rpcclnt == NULL) {
 221                 struct rpc_clnt *clnt;
 222
 223                 /* Bind an rpc client to this host handle (does not
 224                  * perform a portmapper lookup) */
 225                 if (!(clnt = nlm_bind_host(host))) {
 226                         status = -ENOLCK;
 227                         goto done;
 228                 }
 229                 clnt->cl_softrtry = nfssrv->client->cl_softrtry;
 230                 clnt->cl_intr = nfssrv->client->cl_intr;
 231         }
 232
 233         /* Keep the old signal mask */
 234         spin_lock_irqsave(&current->sighand->siglock, flags);
 235         oldset = current->blocked;
 236
 237         /* If we're cleaning up locks because the process is exiting,
 238          * perform the RPC call asynchronously. */
 239         if ((IS_SETLK(cmd) || IS_SETLKW(cmd))
 240             && fl->fl_type == F_UNLCK
 241             && (current->flags & PF_EXITING)) {
 242                 sigfillset(&current->blocked);  /* Mask all signals */
 243                 recalc_sigpending();
 244                 spin_unlock_irqrestore(&current->sighand->siglock, flags);
 245
 246                 call = nlmclnt_alloc_call();
 247                 if (!call) {
 248                         status = -ENOMEM;
 249                         goto out_restore;
 250                 }
 251                 call->a_flags = RPC_TASK_ASYNC;
 252         } else {
 253                 spin_unlock_irqrestore(&current->sighand->siglock, flags);
 254                 memset(call, 0, sizeof(*call));
 255                 locks_init_lock(&call->a_args.lock.fl);
 256                 locks_init_lock(&call->a_res.lock.fl);
 257         }
 258         call->a_host = host;
 259
 260         nlmclnt_locks_init_private(fl, host);
 261
 262         /* Set up the argument struct */
 263         nlmclnt_setlockargs(call, fl);
 264
 265         if (IS_SETLK(cmd) || IS_SETLKW(cmd)) {
 266                 if (fl->fl_type != F_UNLCK) {
 267                         call->a_args.block = IS_SETLKW(cmd) ? 1 : 0;
 268                         status = nlmclnt_lock(call, fl);
 269                 } else
 270                         status = nlmclnt_unlock(call, fl);
 271         } else if (IS_GETLK(cmd))
 272                 status = nlmclnt_test(call, fl);
 273         else
 274                 status = -EINVAL;
 275
 276  out_restore:
 277         spin_lock_irqsave(&current->sighand->siglock, flags);
 278         current->blocked = oldset;
 279         recalc_sigpending();
 280         spin_unlock_irqrestore(&current->sighand->siglock, flags);
 281
 282 done:
 283         dprintk("lockd: clnt proc returns %d\n", status);
 284         nlm_release_host(host);
 285         return status;
 286 }
 287 EXPORT_SYMBOL(nlmclnt_proc);
 288
 289 /*
 290  * Allocate an NLM RPC call struct
 291  */
 292 struct nlm_rqst *
 293 nlmclnt_alloc_call(void)
 294 {
 295         struct nlm_rqst *call;
 296
 297         for(;;) {
 298                 call = kzalloc(sizeof(*call), GFP_KERNEL);
 299                 if (call != NULL) {
 300                         locks_init_lock(&call->a_args.lock.fl);
 301                         locks_init_lock(&call->a_res.lock.fl);
 302                         return call;
 303                 }
 304                 if (signalled())
 305                         break;
 306                 printk("nlmclnt_alloc_call: failed, waiting for memory\n");
 307                 schedule_timeout_interruptible(5*HZ);
 308         }
 309         return NULL;
 310 }
 311
 312 static int nlm_wait_on_grace(wait_queue_head_t *queue)
 313 {
 314         DEFINE_WAIT(wait);
 315         int status = -EINTR;
 316
 317         prepare_to_wait(queue, &wait, TASK_INTERRUPTIBLE);
 318         if (!signalled ()) {
 319                 schedule_timeout(NLMCLNT_GRACE_WAIT);
 320                 try_to_freeze();
 321                 if (!signalled ())
 322                         status = 0;
 323         }
 324         finish_wait(queue, &wait);
 325         return status;
 326 }
 327
 328 /*
 329  * Generic NLM call
 330  */
 331 static int
 332 nlmclnt_call(struct nlm_rqst *req, u32 proc)
 333 {
 334         struct nlm_host *host = req->a_host;
 335         struct rpc_clnt *clnt;
 336         struct nlm_args *argp = &req->a_args;
 337         struct nlm_res  *resp = &req->a_res;
 338         struct rpc_message msg = {
 339                 .rpc_argp       = argp,
 340                 .rpc_resp       = resp,
 341         };
 342         int             status;
 343
 344         dprintk("lockd: call procedure %d on %s\n",
 345                         (int)proc, host->h_name);
 346
 347         do {
 348                 if (host->h_reclaiming && !argp->reclaim)
 349                         goto in_grace_period;
 350
 351                 /* If we have no RPC client yet, create one. */
 352                 if ((clnt = nlm_bind_host(host)) == NULL)
 353                         return -ENOLCK;
 354                 msg.rpc_proc = &clnt->cl_procinfo[proc];
 355
 356                 /* Perform the RPC call. If an error occurs, try again */
 357                 if ((status = rpc_call_sync(clnt, &msg, 0)) < 0) {
 358                         dprintk("lockd: rpc_call returned error %d\n", -status);
 359                         switch (status) {
 360                         case -EPROTONOSUPPORT:
 361                                 status = -EINVAL;
 362                                 break;
 363                         case -ECONNREFUSED:
 364                         case -ETIMEDOUT:
 365                         case -ENOTCONN:
 366                                 nlm_rebind_host(host);
 367                                 status = -EAGAIN;
 368                                 break;
 369                         case -ERESTARTSYS:
 370                                 return signalled () ? -EINTR : status;
 371                         default:
 372                                 break;
 373                         }
 374                         break;
 375                 } else
 376                 if (resp->status == NLM_LCK_DENIED_GRACE_PERIOD) {
 377                         dprintk("lockd: server in grace period\n");
 378                         if (argp->reclaim) {
 379                                 printk(KERN_WARNING
 380                                      "lockd: spurious grace period reject?!\n");
 381                                 return -ENOLCK;
 382                         }
 383                 } else {
 384                         if (!argp->reclaim) {
 385                                 /* We appear to be out of the grace period */
 386                                 wake_up_all(&host->h_gracewait);
 387                         }
 388                         dprintk("lockd: server returns status %d\n", resp->status);
 389                         return 0;       /* Okay, call complete */
 390                 }
 391
 392 in_grace_period:
 393                 /*
 394                  * The server has rebooted and appears to be in the grace
 395                  * period during which locks are only allowed to be
 396                  * reclaimed.
 397                  * We can only back off and try again later.
 398                  */
 399                 status = nlm_wait_on_grace(&host->h_gracewait);
 400         } while (status == 0);
 401
 402         return status;
 403 }
 404
 405 /*
 406  * Generic NLM call, async version.
 407  */
 408 int nlmsvc_async_call(struct nlm_rqst *req, u32 proc, const struct rpc_call_ops *tk_ops)
 409 {
 410         struct nlm_host *host = req->a_host;
 411         struct rpc_clnt *clnt;
 412         struct rpc_message msg = {
 413                 .rpc_argp       = &req->a_args,
 414                 .rpc_resp       = &req->a_res,
 415         };
 416         int             status;
 417
 418         dprintk("lockd: call procedure %d on %s (async)\n",
 419                         (int)proc, host->h_name);
 420
 421         /* If we have no RPC client yet, create one. */
 422         if ((clnt = nlm_bind_host(host)) == NULL)
 423                 return -ENOLCK;
 424         msg.rpc_proc = &clnt->cl_procinfo[proc];
 425
 426         /* bootstrap and kick off the async RPC call */
 427         status = rpc_call_async(clnt, &msg, RPC_TASK_ASYNC, tk_ops, req);
 428
 429         return status;
 430 }
 431
 432 static int nlmclnt_async_call(struct nlm_rqst *req, u32 proc, const struct rpc_call_ops *tk_ops)
 433 {
 434         struct nlm_host *host = req->a_host;
 435         struct rpc_clnt *clnt;
 436         struct nlm_args *argp = &req->a_args;
 437         struct nlm_res  *resp = &req->a_res;
 438         struct rpc_message msg = {
 439                 .rpc_argp       = argp,
 440                 .rpc_resp       = resp,
 441         };
 442         int             status;
 443
 444         dprintk("lockd: call procedure %d on %s (async)\n",
 445                         (int)proc, host->h_name);
 446
 447         /* If we have no RPC client yet, create one. */
 448         if ((clnt = nlm_bind_host(host)) == NULL)
 449                 return -ENOLCK;
 450         msg.rpc_proc = &clnt->cl_procinfo[proc];
 451
 452         /* Increment host refcount */
 453         nlm_get_host(host);
 454         /* bootstrap and kick off the async RPC call */
 455         status = rpc_call_async(clnt, &msg, RPC_TASK_ASYNC, tk_ops, req);
 456         if (status < 0)
 457                 nlm_release_host(host);
 458         return status;
 459 }
 460
 461 /*
 462  * TEST for the presence of a conflicting lock
 463  */
 464 static int
 465 nlmclnt_test(struct nlm_rqst *req, struct file_lock *fl)
 466 {
 467         int     status;
 468
 469         status = nlmclnt_call(req, NLMPROC_TEST);
 470         nlmclnt_release_lockargs(req);
 471         if (status < 0)
 472                 return status;
 473
 474         status = req->a_res.status;
 475         if (status == NLM_LCK_GRANTED) {
 476                 fl->fl_type = F_UNLCK;
 477         } if (status == NLM_LCK_DENIED) {
 478                 /*
 479                  * Report the conflicting lock back to the application.
 480                  */
 481                 locks_copy_lock(fl, &req->a_res.lock.fl);
 482                 fl->fl_pid = 0;
 483         } else {
 484                 return nlm_stat_to_errno(req->a_res.status);
 485         }
 486
 487         return 0;
 488 }
 489
 490 static void nlmclnt_locks_copy_lock(struct file_lock *new, struct file_lock *fl)
 491 {
 492         memcpy(&new->fl_u.nfs_fl, &fl->fl_u.nfs_fl, sizeof(new->fl_u.nfs_fl));
 493         nlm_get_lockowner(new->fl_u.nfs_fl.owner);
 494 }
 495
 496 static void nlmclnt_locks_release_private(struct file_lock *fl)
 497 {
 498         nlm_put_lockowner(fl->fl_u.nfs_fl.owner);
 499         fl->fl_ops = NULL;
 500 }
 501
 502 static struct file_lock_operations nlmclnt_lock_ops = {
 503         .fl_copy_lock = nlmclnt_locks_copy_lock,
 504         .fl_release_private = nlmclnt_locks_release_private,
 505 };
 506
 507 static void nlmclnt_locks_init_private(struct file_lock *fl, struct nlm_host *host)
 508 {
 509         BUG_ON(fl->fl_ops != NULL);
 510         fl->fl_u.nfs_fl.state = 0;
 511         fl->fl_u.nfs_fl.flags = 0;
 512         fl->fl_u.nfs_fl.owner = nlm_find_lockowner(host, fl->fl_owner);
 513         fl->fl_ops = &nlmclnt_lock_ops;
 514 }
 515
 516 static void do_vfs_lock(struct file_lock *fl)
 517 {
 518         int res = 0;
 519         switch (fl->fl_flags & (FL_POSIX|FL_FLOCK)) {
 520                 case FL_POSIX:
 521                         res = posix_lock_file_wait(fl->fl_file, fl);
 522                         break;
 523                 case FL_FLOCK:
 524                         res = flock_lock_file_wait(fl->fl_file, fl);
 525                         break;
 526                 default:
 527                         BUG();
 528         }
 529         if (res < 0)
 530                 printk(KERN_WARNING "%s: VFS is out of sync with lock manager!\n",
 531                                 __FUNCTION__);
 532 }
 533
 534 /*
 535  * LOCK: Try to create a lock
 536  *
 537  *                      Programmer Harassment Alert
 538  *
 539  * When given a blocking lock request in a sync RPC call, the HPUX lockd
 540  * will faithfully return LCK_BLOCKED but never cares to notify us when
 541  * the lock could be granted. This way, our local process could hang
 542  * around forever waiting for the callback.
 543  *
 544  *  Solution A: Implement busy-waiting
 545  *  Solution B: Use the async version of the call (NLM_LOCK_{MSG,RES})
 546  *
 547  * For now I am implementing solution A, because I hate the idea of
 548  * re-implementing lockd for a third time in two months. The async
 549  * calls shouldn't be too hard to do, however.
 550  *
 551  * This is one of the lovely things about standards in the NFS area:
 552  * they're so soft and squishy you can't really blame HP for doing this.
 553  */
 554 static int
 555 nlmclnt_lock(struct nlm_rqst *req, struct file_lock *fl)
 556 {
 557         struct nlm_host *host = req->a_host;
 558         struct nlm_res  *resp = &req->a_res;
 559         long timeout;
 560         int status;
 561
 562         if (!host->h_monitored && nsm_monitor(host) < 0) {
 563                 printk(KERN_NOTICE "lockd: failed to monitor %s\n",
 564                                         host->h_name);
 565                 status = -ENOLCK;
 566                 goto out;
 567         }
 568
 569         if (req->a_args.block) {
 570                 status = nlmclnt_prepare_block(req, host, fl);
 571                 if (status < 0)
 572                         goto out;
 573         }
 574         for(;;) {
 575                 status = nlmclnt_call(req, NLMPROC_LOCK);
 576                 if (status < 0)
 577                         goto out_unblock;
 578                 if (resp->status != NLM_LCK_BLOCKED)
 579                         break;
 580                 /* Wait on an NLM blocking lock */
 581                 timeout = nlmclnt_block(req, NLMCLNT_POLL_TIMEOUT);
 582                 /* Did a reclaimer thread notify us of a server reboot? */
 583                 if (resp->status ==  NLM_LCK_DENIED_GRACE_PERIOD)
 584                         continue;
 585                 if (resp->status != NLM_LCK_BLOCKED)
 586                         break;
 587                 if (timeout >= 0)
 588                         continue;
 589                 /* We were interrupted. Send a CANCEL request to the server
 590                  * and exit
 591                  */
 592                 status = (int)timeout;
 593                 goto out_unblock;
 594         }
 595
 596         if (resp->status == NLM_LCK_GRANTED) {
 597                 fl->fl_u.nfs_fl.state = host->h_state;
 598                 fl->fl_u.nfs_fl.flags |= NFS_LCK_GRANTED;
 599                 fl->fl_flags |= FL_SLEEP;
 600                 do_vfs_lock(fl);
 601         }
 602         status = nlm_stat_to_errno(resp->status);
 603 out_unblock:
 604         nlmclnt_finish_block(req);
 605         /* Cancel the blocked request if it is still pending */
 606         if (resp->status == NLM_LCK_BLOCKED)
 607                 nlmclnt_cancel(host, req->a_args.block, fl);
 608 out:
 609         nlmclnt_release_lockargs(req);
 610         return status;
 611 }
 612
 613 /*
 614  * RECLAIM: Try to reclaim a lock
 615  */
 616 int
 617 nlmclnt_reclaim(struct nlm_host *host, struct file_lock *fl)
 618 {
 619         struct nlm_rqst reqst, *req;
 620         int             status;
 621
 622         req = &reqst;
 623         memset(req, 0, sizeof(*req));
 624         locks_init_lock(&req->a_args.lock.fl);
 625         locks_init_lock(&req->a_res.lock.fl);
 626         req->a_host  = host;
 627         req->a_flags = 0;
 628
 629         /* Set up the argument struct */
 630         nlmclnt_setlockargs(req, fl);
 631         req->a_args.reclaim = 1;
 632
 633         if ((status = nlmclnt_call(req, NLMPROC_LOCK)) >= 0
 634          && req->a_res.status == NLM_LCK_GRANTED)
 635                 return 0;
 636
 637         printk(KERN_WARNING "lockd: failed to reclaim lock for pid %d "
 638                                 "(errno %d, status %d)\n", fl->fl_pid,
 639                                 status, req->a_res.status);
 640
 641         /*
 642          * FIXME: This is a serious failure. We can
 643          *
 644          *  a.  Ignore the problem
 645          *  b.  Send the owning process some signal (Linux doesn't have
 646          *      SIGLOST, though...)
 647          *  c.  Retry the operation
 648          *
 649          * Until someone comes up with a simple implementation
 650          * for b or c, I'll choose option a.
 651          */
 652
 653         return -ENOLCK;
 654 }
 655
 656 /*
 657  * UNLOCK: remove an existing lock
 658  */
 659 static int
 660 nlmclnt_unlock(struct nlm_rqst *req, struct file_lock *fl)
 661 {
 662         struct nlm_res  *resp = &req->a_res;
 663         int             status;
 664
 665         /* Clean the GRANTED flag now so the lock doesn't get
 666          * reclaimed while we're stuck in the unlock call. */
 667         fl->fl_u.nfs_fl.flags &= ~NFS_LCK_GRANTED;
 668
 669         /*
 670          * Note: the server is supposed to either grant us the unlock
 671          * request, or to deny it with NLM_LCK_DENIED_GRACE_PERIOD. In either
 672          * case, we want to unlock.
 673          */
 674         do_vfs_lock(fl);
 675
 676         if (req->a_flags & RPC_TASK_ASYNC) {
 677                 status = nlmclnt_async_call(req, NLMPROC_UNLOCK,
 678                                         &nlmclnt_unlock_ops);
 679                 /* Hrmf... Do the unlock early since locks_remove_posix()
 680                  * really expects us to free the lock synchronously */
 681                 if (status < 0) {
 682                         nlmclnt_release_lockargs(req);
 683                         kfree(req);
 684                 }
 685                 return status;
 686         }
 687
 688         status = nlmclnt_call(req, NLMPROC_UNLOCK);
 689         nlmclnt_release_lockargs(req);
 690         if (status < 0)
 691                 return status;
 692
 693         if (resp->status == NLM_LCK_GRANTED)
 694                 return 0;
 695
 696         if (resp->status != NLM_LCK_DENIED_NOLOCKS)
 697                 printk("lockd: unexpected unlock status: %d\n", resp->status);
 698
 699         /* What to do now? I'm out of my depth... */
 700
 701         return -ENOLCK;
 702 }
 703
 704 static void nlmclnt_unlock_callback(struct rpc_task *task, void *data)
 705 {
 706         struct nlm_rqst *req = data;
 707         int             status = req->a_res.status;
 708
 709         if (RPC_ASSASSINATED(task))
 710                 goto die;
 711
 712         if (task->tk_status < 0) {
 713                 dprintk("lockd: unlock failed (err = %d)\n", -task->tk_status);
 714                 goto retry_rebind;
 715         }
 716         if (status == NLM_LCK_DENIED_GRACE_PERIOD) {
 717                 rpc_delay(task, NLMCLNT_GRACE_WAIT);
 718                 goto retry_unlock;
 719         }
 720         if (status != NLM_LCK_GRANTED)
 721                 printk(KERN_WARNING "lockd: unexpected unlock status: %d\n", status);
 722 die:
 723         nlm_release_host(req->a_host);
 724         nlmclnt_release_lockargs(req);
 725         kfree(req);
 726         return;
 727  retry_rebind:
 728         nlm_rebind_host(req->a_host);
 729  retry_unlock:
 730         rpc_restart_call(task);
 731 }
 732
 733 static const struct rpc_call_ops nlmclnt_unlock_ops = {
 734         .rpc_call_done = nlmclnt_unlock_callback,
 735 };
 736
 737 /*
 738  * Cancel a blocked lock request.
 739  * We always use an async RPC call for this in order not to hang a
 740  * process that has been Ctrl-C'ed.
 741  */
 742 static int nlmclnt_cancel(struct nlm_host *host, int block, struct file_lock *fl)
 743 {
 744         struct nlm_rqst *req;
 745         unsigned long   flags;
 746         sigset_t        oldset;
 747         int             status;
 748
 749         /* Block all signals while setting up call */
 750         spin_lock_irqsave(&current->sighand->siglock, flags);
 751         oldset = current->blocked;
 752         sigfillset(&current->blocked);
 753         recalc_sigpending();
 754         spin_unlock_irqrestore(&current->sighand->siglock, flags);
 755
 756         req = nlmclnt_alloc_call();
 757         if (!req)
 758                 return -ENOMEM;
 759         req->a_host  = host;
 760         req->a_flags = RPC_TASK_ASYNC;
 761
 762         nlmclnt_setlockargs(req, fl);
 763         req->a_args.block = block;
 764
 765         status = nlmclnt_async_call(req, NLMPROC_CANCEL, &nlmclnt_cancel_ops);
 766         if (status < 0) {
 767                 nlmclnt_release_lockargs(req);
 768                 kfree(req);
 769         }
 770
 771         spin_lock_irqsave(&current->sighand->siglock, flags);
 772         current->blocked = oldset;
 773         recalc_sigpending();
 774         spin_unlock_irqrestore(&current->sighand->siglock, flags);
 775
 776         return status;
 777 }
 778
 779 static void nlmclnt_cancel_callback(struct rpc_task *task, void *data)
 780 {
 781         struct nlm_rqst *req = data;
 782
 783         if (RPC_ASSASSINATED(task))
 784                 goto die;
 785
 786         if (task->tk_status < 0) {
 787                 dprintk("lockd: CANCEL call error %d, retrying.\n",
 788                                         task->tk_status);
 789                 goto retry_cancel;
 790         }
 791
 792         dprintk("lockd: cancel status %d (task %d)\n",
 793                         req->a_res.status, task->tk_pid);
 794
 795         switch (req->a_res.status) {
 796         case NLM_LCK_GRANTED:
 797         case NLM_LCK_DENIED_GRACE_PERIOD:
 798                 /* Everything's good */
 799                 break;
 800         case NLM_LCK_DENIED_NOLOCKS:
 801                 dprintk("lockd: CANCEL failed (server has no locks)\n");
 802                 goto retry_cancel;
 803         default:
 804                 printk(KERN_NOTICE "lockd: weird return %d for CANCEL call\n",
 805                         req->a_res.status);
 806         }
 807
 808 die:
 809         nlm_release_host(req->a_host);
 810         nlmclnt_release_lockargs(req);
 811         kfree(req);
 812         return;
 813
 814 retry_cancel:
 815         /* Don't ever retry more than 3 times */
 816         if (req->a_retries++ >= NLMCLNT_MAX_RETRIES)
 817                 goto die;
 818         nlm_rebind_host(req->a_host);
 819         rpc_restart_call(task);
 820         rpc_delay(task, 30 * HZ);
 821 }
 822
 823 static const struct rpc_call_ops nlmclnt_cancel_ops = {
 824         .rpc_call_done = nlmclnt_cancel_callback,
 825 };
 826
 827 /*
 828  * Convert an NLM status code to a generic kernel errno
 829  */
 830 static int
 831 nlm_stat_to_errno(u32 status)
 832 {
 833         switch(status) {
 834         case NLM_LCK_GRANTED:
 835                 return 0;
 836         case NLM_LCK_DENIED:
 837                 return -EAGAIN;
 838         case NLM_LCK_DENIED_NOLOCKS:
 839         case NLM_LCK_DENIED_GRACE_PERIOD:
 840                 return -ENOLCK;
 841         case NLM_LCK_BLOCKED:
 842                 printk(KERN_NOTICE "lockd: unexpected status NLM_BLOCKED\n");
 843                 return -ENOLCK;
 844 #ifdef CONFIG_LOCKD_V4
 845         case NLM_DEADLCK:
 846                 return -EDEADLK;
 847         case NLM_ROFS:
 848                 return -EROFS;
 849         case NLM_STALE_FH:
 850                 return -ESTALE;
 851         case NLM_FBIG:
 852                 return -EOVERFLOW;
 853         case NLM_FAILED:
 854                 return -ENOLCK;
 855 #endif
 856         }
 857         printk(KERN_NOTICE "lockd: unexpected server status %d\n", status);
 858         return -ENOLCK;
 859 }