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 #include <linux/vs_cvirt.h>
  22
  23 #define NLMDBG_FACILITY         NLMDBG_CLIENT
  24 #define NLMCLNT_GRACE_WAIT      (5*HZ)
  25 #define NLMCLNT_POLL_TIMEOUT    (30*HZ)
  26 #define NLMCLNT_MAX_RETRIES     3
  27
  28 static int      nlmclnt_test(struct nlm_rqst *, struct file_lock *);
  29 static int      nlmclnt_lock(struct nlm_rqst *, struct file_lock *);
  30 static int      nlmclnt_unlock(struct nlm_rqst *, struct file_lock *);
  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 static int      nlmclnt_cancel(struct nlm_host *, int , struct file_lock *);
  34
  35 static const struct rpc_call_ops nlmclnt_unlock_ops;
  36 static const struct rpc_call_ops nlmclnt_cancel_ops;
  37
  38 /*
  39  * Cookie counter for NLM requests
  40  */
  41 static u32      nlm_cookie = 0x1234;
  42
  43 static inline void nlmclnt_next_cookie(struct nlm_cookie *c)
  44 {
  45         memcpy(c->data, &nlm_cookie, 4);
  46         memset(c->data+4, 0, 4);
  47         c->len=4;
  48         nlm_cookie++;
  49 }
  50
  51 static struct nlm_lockowner *nlm_get_lockowner(struct nlm_lockowner *lockowner)
  52 {
  53         atomic_inc(&lockowner->count);
  54         return lockowner;
  55 }
  56
  57 static void nlm_put_lockowner(struct nlm_lockowner *lockowner)
  58 {
  59         if (!atomic_dec_and_lock(&lockowner->count, &lockowner->host->h_lock))
  60                 return;
  61         list_del(&lockowner->list);
  62         spin_unlock(&lockowner->host->h_lock);
  63         nlm_release_host(lockowner->host);
  64         kfree(lockowner);
  65 }
  66
  67 static inline int nlm_pidbusy(struct nlm_host *host, uint32_t pid)
  68 {
  69         struct nlm_lockowner *lockowner;
  70         list_for_each_entry(lockowner, &host->h_lockowners, list) {
  71                 if (lockowner->pid == pid)
  72                         return -EBUSY;
  73         }
  74         return 0;
  75 }
  76
  77 static inline uint32_t __nlm_alloc_pid(struct nlm_host *host)
  78 {
  79         uint32_t res;
  80         do {
  81                 res = host->h_pidcount++;
  82         } while (nlm_pidbusy(host, res) < 0);
  83         return res;
  84 }
  85
  86 static struct nlm_lockowner *__nlm_find_lockowner(struct nlm_host *host, fl_owner_t owner)
  87 {
  88         struct nlm_lockowner *lockowner;
  89         list_for_each_entry(lockowner, &host->h_lockowners, list) {
  90                 if (lockowner->owner != owner)
  91                         continue;
  92                 return nlm_get_lockowner(lockowner);
  93         }
  94         return NULL;
  95 }
  96
  97 static struct nlm_lockowner *nlm_find_lockowner(struct nlm_host *host, fl_owner_t owner)
  98 {
  99         struct nlm_lockowner *res, *new = NULL;
 100
 101         spin_lock(&host->h_lock);
 102         res = __nlm_find_lockowner(host, owner);
 103         if (res == NULL) {
 104                 spin_unlock(&host->h_lock);
 105                 new = (struct nlm_lockowner *)kmalloc(sizeof(*new), GFP_KERNEL);
 106                 spin_lock(&host->h_lock);
 107                 res = __nlm_find_lockowner(host, owner);
 108                 if (res == NULL && new != NULL) {
 109                         res = new;
 110                         atomic_set(&new->count, 1);
 111                         new->owner = owner;
 112                         new->pid = __nlm_alloc_pid(host);
 113                         new->host = nlm_get_host(host);
 114                         list_add(&new->list, &host->h_lockowners);
 115                         new = NULL;
 116                 }
 117         }
 118         spin_unlock(&host->h_lock);
 119         kfree(new);
 120         return res;
 121 }
 122
 123 /*
 124  * Initialize arguments for TEST/LOCK/UNLOCK/CANCEL calls
 125  */
 126 static void nlmclnt_setlockargs(struct nlm_rqst *req, struct file_lock *fl)
 127 {
 128         struct nlm_args *argp = &req->a_args;
 129         struct nlm_lock *lock = &argp->lock;
 130
 131         nlmclnt_next_cookie(&argp->cookie);
 132         argp->state   = nsm_local_state;
 133         memcpy(&lock->fh, NFS_FH(fl->fl_file->f_dentry->d_inode), sizeof(struct nfs_fh));
 134         lock->caller  = vx_new_uts(nodename);
 135         lock->oh.data = req->a_owner;
 136         lock->oh.len  = snprintf(req->a_owner, sizeof(req->a_owner), "%u@%s",
 137                                 (unsigned int)fl->fl_u.nfs_fl.owner->pid,
 138                                 vx_new_uts(nodename));
 139         lock->svid = fl->fl_u.nfs_fl.owner->pid;
 140         lock->fl.fl_start = fl->fl_start;
 141         lock->fl.fl_end = fl->fl_end;
 142         lock->fl.fl_type = fl->fl_type;
 143 }
 144
 145 static void nlmclnt_release_lockargs(struct nlm_rqst *req)
 146 {
 147         BUG_ON(req->a_args.lock.fl.fl_ops != NULL);
 148 }
 149
 150 /*
 151  * This is the main entry point for the NLM client.
 152  */
 153 int
 154 nlmclnt_proc(struct inode *inode, int cmd, struct file_lock *fl)
 155 {
 156         struct nlm_host         *host;
 157         struct nlm_rqst         *call;
 158         sigset_t                oldset;
 159         unsigned long           flags;
 160         int                     status, proto, vers;
 161
 162         vers = (NFS_PROTO(inode)->version == 3) ? 4 : 1;
 163         if (NFS_PROTO(inode)->version > 3) {
 164                 printk(KERN_NOTICE "NFSv4 file locking not implemented!\n");
 165                 return -ENOLCK;
 166         }
 167
 168         /* Retrieve transport protocol from NFS client */
 169         proto = NFS_CLIENT(inode)->cl_xprt->prot;
 170
 171         host = nlmclnt_lookup_host(NFS_ADDR(inode), proto, vers);
 172         if (host == NULL)
 173                 return -ENOLCK;
 174
 175         call = nlm_alloc_call(host);
 176         if (call == NULL)
 177                 return -ENOMEM;
 178
 179         nlmclnt_locks_init_private(fl, host);
 180         /* Set up the argument struct */
 181         nlmclnt_setlockargs(call, fl);
 182
 183         /* Keep the old signal mask */
 184         spin_lock_irqsave(&current->sighand->siglock, flags);
 185         oldset = current->blocked;
 186
 187         /* If we're cleaning up locks because the process is exiting,
 188          * perform the RPC call asynchronously. */
 189         if ((IS_SETLK(cmd) || IS_SETLKW(cmd))
 190             && fl->fl_type == F_UNLCK
 191             && (current->flags & PF_EXITING)) {
 192                 sigfillset(&current->blocked);  /* Mask all signals */
 193                 recalc_sigpending();
 194
 195                 call->a_flags = RPC_TASK_ASYNC;
 196         }
 197         spin_unlock_irqrestore(&current->sighand->siglock, flags);
 198
 199         if (IS_SETLK(cmd) || IS_SETLKW(cmd)) {
 200                 if (fl->fl_type != F_UNLCK) {
 201                         call->a_args.block = IS_SETLKW(cmd) ? 1 : 0;
 202                         status = nlmclnt_lock(call, fl);
 203                 } else
 204                         status = nlmclnt_unlock(call, fl);
 205         } else if (IS_GETLK(cmd))
 206                 status = nlmclnt_test(call, fl);
 207         else
 208                 status = -EINVAL;
 209
 210         fl->fl_ops->fl_release_private(fl);
 211         fl->fl_ops = NULL;
 212
 213         spin_lock_irqsave(&current->sighand->siglock, flags);
 214         current->blocked = oldset;
 215         recalc_sigpending();
 216         spin_unlock_irqrestore(&current->sighand->siglock, flags);
 217
 218         dprintk("lockd: clnt proc returns %d\n", status);
 219         return status;
 220 }
 221 EXPORT_SYMBOL(nlmclnt_proc);
 222
 223 /*
 224  * Allocate an NLM RPC call struct
 225  *
 226  * Note: the caller must hold a reference to host. In case of failure,
 227  * this reference will be released.
 228  */
 229 struct nlm_rqst *nlm_alloc_call(struct nlm_host *host)
 230 {
 231         struct nlm_rqst *call;
 232
 233         for(;;) {
 234                 call = kzalloc(sizeof(*call), GFP_KERNEL);
 235                 if (call != NULL) {
 236                         locks_init_lock(&call->a_args.lock.fl);
 237                         locks_init_lock(&call->a_res.lock.fl);
 238                         call->a_host = host;
 239                         return call;
 240                 }
 241                 if (signalled())
 242                         break;
 243                 printk("nlm_alloc_call: failed, waiting for memory\n");
 244                 schedule_timeout_interruptible(5*HZ);
 245         }
 246         nlm_release_host(host);
 247         return NULL;
 248 }
 249
 250 void nlm_release_call(struct nlm_rqst *call)
 251 {
 252         nlm_release_host(call->a_host);
 253         nlmclnt_release_lockargs(call);
 254         kfree(call);
 255 }
 256
 257 static void nlmclnt_rpc_release(void *data)
 258 {
 259         return nlm_release_call(data);
 260 }
 261
 262 static int nlm_wait_on_grace(wait_queue_head_t *queue)
 263 {
 264         DEFINE_WAIT(wait);
 265         int status = -EINTR;
 266
 267         prepare_to_wait(queue, &wait, TASK_INTERRUPTIBLE);
 268         if (!signalled ()) {
 269                 schedule_timeout(NLMCLNT_GRACE_WAIT);
 270                 try_to_freeze();
 271                 if (!signalled ())
 272                         status = 0;
 273         }
 274         finish_wait(queue, &wait);
 275         return status;
 276 }
 277
 278 /*
 279  * Generic NLM call
 280  */
 281 static int
 282 nlmclnt_call(struct nlm_rqst *req, u32 proc)
 283 {
 284         struct nlm_host *host = req->a_host;
 285         struct rpc_clnt *clnt;
 286         struct nlm_args *argp = &req->a_args;
 287         struct nlm_res  *resp = &req->a_res;
 288         struct rpc_message msg = {
 289                 .rpc_argp       = argp,
 290                 .rpc_resp       = resp,
 291         };
 292         int             status;
 293
 294         dprintk("lockd: call procedure %d on %s\n",
 295                         (int)proc, host->h_name);
 296
 297         do {
 298                 if (host->h_reclaiming && !argp->reclaim)
 299                         goto in_grace_period;
 300
 301                 /* If we have no RPC client yet, create one. */
 302                 if ((clnt = nlm_bind_host(host)) == NULL)
 303                         return -ENOLCK;
 304                 msg.rpc_proc = &clnt->cl_procinfo[proc];
 305
 306                 /* Perform the RPC call. If an error occurs, try again */
 307                 if ((status = rpc_call_sync(clnt, &msg, 0)) < 0) {
 308                         dprintk("lockd: rpc_call returned error %d\n", -status);
 309                         switch (status) {
 310                         case -EPROTONOSUPPORT:
 311                                 status = -EINVAL;
 312                                 break;
 313                         case -ECONNREFUSED:
 314                         case -ETIMEDOUT:
 315                         case -ENOTCONN:
 316                                 nlm_rebind_host(host);
 317                                 status = -EAGAIN;
 318                                 break;
 319                         case -ERESTARTSYS:
 320                                 return signalled () ? -EINTR : status;
 321                         default:
 322                                 break;
 323                         }
 324                         break;
 325                 } else
 326                 if (resp->status == NLM_LCK_DENIED_GRACE_PERIOD) {
 327                         dprintk("lockd: server in grace period\n");
 328                         if (argp->reclaim) {
 329                                 printk(KERN_WARNING
 330                                      "lockd: spurious grace period reject?!\n");
 331                                 return -ENOLCK;
 332                         }
 333                 } else {
 334                         if (!argp->reclaim) {
 335                                 /* We appear to be out of the grace period */
 336                                 wake_up_all(&host->h_gracewait);
 337                         }
 338                         dprintk("lockd: server returns status %d\n", resp->status);
 339                         return 0;       /* Okay, call complete */
 340                 }
 341
 342 in_grace_period:
 343                 /*
 344                  * The server has rebooted and appears to be in the grace
 345                  * period during which locks are only allowed to be
 346                  * reclaimed.
 347                  * We can only back off and try again later.
 348                  */
 349                 status = nlm_wait_on_grace(&host->h_gracewait);
 350         } while (status == 0);
 351
 352         return status;
 353 }
 354
 355 /*
 356  * Generic NLM call, async version.
 357  */
 358 static int __nlm_async_call(struct nlm_rqst *req, u32 proc, struct rpc_message *msg, const struct rpc_call_ops *tk_ops)
 359 {
 360         struct nlm_host *host = req->a_host;
 361         struct rpc_clnt *clnt;
 362         int status = -ENOLCK;
 363
 364         dprintk("lockd: call procedure %d on %s (async)\n",
 365                         (int)proc, host->h_name);
 366
 367         /* If we have no RPC client yet, create one. */
 368         clnt = nlm_bind_host(host);
 369         if (clnt == NULL)
 370                 goto out_err;
 371         msg->rpc_proc = &clnt->cl_procinfo[proc];
 372
 373         /* bootstrap and kick off the async RPC call */
 374         status = rpc_call_async(clnt, msg, RPC_TASK_ASYNC, tk_ops, req);
 375         if (status == 0)
 376                 return 0;
 377 out_err:
 378         nlm_release_call(req);
 379         return status;
 380 }
 381
 382 int nlm_async_call(struct nlm_rqst *req, u32 proc, const struct rpc_call_ops *tk_ops)
 383 {
 384         struct rpc_message msg = {
 385                 .rpc_argp       = &req->a_args,
 386                 .rpc_resp       = &req->a_res,
 387         };
 388         return __nlm_async_call(req, proc, &msg, tk_ops);
 389 }
 390
 391 int nlm_async_reply(struct nlm_rqst *req, u32 proc, const struct rpc_call_ops *tk_ops)
 392 {
 393         struct rpc_message msg = {
 394                 .rpc_argp       = &req->a_res,
 395         };
 396         return __nlm_async_call(req, proc, &msg, tk_ops);
 397 }
 398
 399 /*
 400  * TEST for the presence of a conflicting lock
 401  */
 402 static int
 403 nlmclnt_test(struct nlm_rqst *req, struct file_lock *fl)
 404 {
 405         int     status;
 406
 407         status = nlmclnt_call(req, NLMPROC_TEST);
 408         if (status < 0)
 409                 goto out;
 410
 411         switch (req->a_res.status) {
 412                 case NLM_LCK_GRANTED:
 413                         fl->fl_type = F_UNLCK;
 414                         break;
 415                 case NLM_LCK_DENIED:
 416                         /*
 417                          * Report the conflicting lock back to the application.
 418                          */
 419                         fl->fl_start = req->a_res.lock.fl.fl_start;
 420                         fl->fl_end = req->a_res.lock.fl.fl_start;
 421                         fl->fl_type = req->a_res.lock.fl.fl_type;
 422                         fl->fl_pid = 0;
 423                         break;
 424                 default:
 425                         status = nlm_stat_to_errno(req->a_res.status);
 426         }
 427 out:
 428         nlm_release_call(req);
 429         return status;
 430 }
 431
 432 static void nlmclnt_locks_copy_lock(struct file_lock *new, struct file_lock *fl)
 433 {
 434         new->fl_u.nfs_fl.state = fl->fl_u.nfs_fl.state;
 435         new->fl_u.nfs_fl.owner = nlm_get_lockowner(fl->fl_u.nfs_fl.owner);
 436         list_add_tail(&new->fl_u.nfs_fl.list, &fl->fl_u.nfs_fl.owner->host->h_granted);
 437 }
 438
 439 static void nlmclnt_locks_release_private(struct file_lock *fl)
 440 {
 441         list_del(&fl->fl_u.nfs_fl.list);
 442         nlm_put_lockowner(fl->fl_u.nfs_fl.owner);
 443 }
 444
 445 static struct file_lock_operations nlmclnt_lock_ops = {
 446         .fl_copy_lock = nlmclnt_locks_copy_lock,
 447         .fl_release_private = nlmclnt_locks_release_private,
 448 };
 449
 450 static void nlmclnt_locks_init_private(struct file_lock *fl, struct nlm_host *host)
 451 {
 452         BUG_ON(fl->fl_ops != NULL);
 453         fl->fl_u.nfs_fl.state = 0;
 454         fl->fl_u.nfs_fl.owner = nlm_find_lockowner(host, fl->fl_owner);
 455         INIT_LIST_HEAD(&fl->fl_u.nfs_fl.list);
 456         fl->fl_ops = &nlmclnt_lock_ops;
 457 }
 458
 459 static void do_vfs_lock(struct file_lock *fl)
 460 {
 461         int res = 0;
 462         switch (fl->fl_flags & (FL_POSIX|FL_FLOCK)) {
 463                 case FL_POSIX:
 464                         res = posix_lock_file_wait(fl->fl_file, fl);
 465                         break;
 466                 case FL_FLOCK:
 467                         res = flock_lock_file_wait(fl->fl_file, fl);
 468                         break;
 469                 default:
 470                         BUG();
 471         }
 472         if (res < 0)
 473                 printk(KERN_WARNING "%s: VFS is out of sync with lock manager!\n",
 474                                 __FUNCTION__);
 475 }
 476
 477 /*
 478  * LOCK: Try to create a lock
 479  *
 480  *                      Programmer Harassment Alert
 481  *
 482  * When given a blocking lock request in a sync RPC call, the HPUX lockd
 483  * will faithfully return LCK_BLOCKED but never cares to notify us when
 484  * the lock could be granted. This way, our local process could hang
 485  * around forever waiting for the callback.
 486  *
 487  *  Solution A: Implement busy-waiting
 488  *  Solution B: Use the async version of the call (NLM_LOCK_{MSG,RES})
 489  *
 490  * For now I am implementing solution A, because I hate the idea of
 491  * re-implementing lockd for a third time in two months. The async
 492  * calls shouldn't be too hard to do, however.
 493  *
 494  * This is one of the lovely things about standards in the NFS area:
 495  * they're so soft and squishy you can't really blame HP for doing this.
 496  */
 497 static int
 498 nlmclnt_lock(struct nlm_rqst *req, struct file_lock *fl)
 499 {
 500         struct nlm_host *host = req->a_host;
 501         struct nlm_res  *resp = &req->a_res;
 502         struct nlm_wait *block = NULL;
 503         int status = -ENOLCK;
 504
 505         if (!host->h_monitored && nsm_monitor(host) < 0) {
 506                 printk(KERN_NOTICE "lockd: failed to monitor %s\n",
 507                                         host->h_name);
 508                 goto out;
 509         }
 510
 511         block = nlmclnt_prepare_block(host, fl);
 512         for(;;) {
 513                 status = nlmclnt_call(req, NLMPROC_LOCK);
 514                 if (status < 0)
 515                         goto out_unblock;
 516                 if (!req->a_args.block)
 517                         break;
 518                 /* Did a reclaimer thread notify us of a server reboot? */
 519                 if (resp->status ==  NLM_LCK_DENIED_GRACE_PERIOD)
 520                         continue;
 521                 if (resp->status != NLM_LCK_BLOCKED)
 522                         break;
 523                 /* Wait on an NLM blocking lock */
 524                 status = nlmclnt_block(block, req, NLMCLNT_POLL_TIMEOUT);
 525                 /* if we were interrupted. Send a CANCEL request to the server
 526                  * and exit
 527                  */
 528                 if (status < 0)
 529                         goto out_unblock;
 530                 if (resp->status != NLM_LCK_BLOCKED)
 531                         break;
 532         }
 533
 534         if (resp->status == NLM_LCK_GRANTED) {
 535                 fl->fl_u.nfs_fl.state = host->h_state;
 536                 fl->fl_flags |= FL_SLEEP;
 537                 /* Ensure the resulting lock will get added to granted list */
 538                 do_vfs_lock(fl);
 539         }
 540         status = nlm_stat_to_errno(resp->status);
 541 out_unblock:
 542         nlmclnt_finish_block(block);
 543         /* Cancel the blocked request if it is still pending */
 544         if (resp->status == NLM_LCK_BLOCKED)
 545                 nlmclnt_cancel(host, req->a_args.block, fl);
 546 out:
 547         nlm_release_call(req);
 548         return status;
 549 }
 550
 551 /*
 552  * RECLAIM: Try to reclaim a lock
 553  */
 554 int
 555 nlmclnt_reclaim(struct nlm_host *host, struct file_lock *fl)
 556 {
 557         struct nlm_rqst reqst, *req;
 558         int             status;
 559
 560         req = &reqst;
 561         memset(req, 0, sizeof(*req));
 562         locks_init_lock(&req->a_args.lock.fl);
 563         locks_init_lock(&req->a_res.lock.fl);
 564         req->a_host  = host;
 565         req->a_flags = 0;
 566
 567         /* Set up the argument struct */
 568         nlmclnt_setlockargs(req, fl);
 569         req->a_args.reclaim = 1;
 570
 571         if ((status = nlmclnt_call(req, NLMPROC_LOCK)) >= 0
 572          && req->a_res.status == NLM_LCK_GRANTED)
 573                 return 0;
 574
 575         printk(KERN_WARNING "lockd: failed to reclaim lock for pid %d "
 576                                 "(errno %d, status %d)\n", fl->fl_pid,
 577                                 status, req->a_res.status);
 578
 579         /*
 580          * FIXME: This is a serious failure. We can
 581          *
 582          *  a.  Ignore the problem
 583          *  b.  Send the owning process some signal (Linux doesn't have
 584          *      SIGLOST, though...)
 585          *  c.  Retry the operation
 586          *
 587          * Until someone comes up with a simple implementation
 588          * for b or c, I'll choose option a.
 589          */
 590
 591         return -ENOLCK;
 592 }
 593
 594 /*
 595  * UNLOCK: remove an existing lock
 596  */
 597 static int
 598 nlmclnt_unlock(struct nlm_rqst *req, struct file_lock *fl)
 599 {
 600         struct nlm_res  *resp = &req->a_res;
 601         int             status;
 602
 603         /*
 604          * Note: the server is supposed to either grant us the unlock
 605          * request, or to deny it with NLM_LCK_DENIED_GRACE_PERIOD. In either
 606          * case, we want to unlock.
 607          */
 608         do_vfs_lock(fl);
 609
 610         if (req->a_flags & RPC_TASK_ASYNC)
 611                 return nlm_async_call(req, NLMPROC_UNLOCK, &nlmclnt_unlock_ops);
 612
 613         status = nlmclnt_call(req, NLMPROC_UNLOCK);
 614         if (status < 0)
 615                 goto out;
 616
 617         status = 0;
 618         if (resp->status == NLM_LCK_GRANTED)
 619                 goto out;
 620
 621         if (resp->status != NLM_LCK_DENIED_NOLOCKS)
 622                 printk("lockd: unexpected unlock status: %d\n", resp->status);
 623         /* What to do now? I'm out of my depth... */
 624         status = -ENOLCK;
 625 out:
 626         nlm_release_call(req);
 627         return status;
 628 }
 629
 630 static void nlmclnt_unlock_callback(struct rpc_task *task, void *data)
 631 {
 632         struct nlm_rqst *req = data;
 633         int             status = req->a_res.status;
 634
 635         if (RPC_ASSASSINATED(task))
 636                 goto die;
 637
 638         if (task->tk_status < 0) {
 639                 dprintk("lockd: unlock failed (err = %d)\n", -task->tk_status);
 640                 goto retry_rebind;
 641         }
 642         if (status == NLM_LCK_DENIED_GRACE_PERIOD) {
 643                 rpc_delay(task, NLMCLNT_GRACE_WAIT);
 644                 goto retry_unlock;
 645         }
 646         if (status != NLM_LCK_GRANTED)
 647                 printk(KERN_WARNING "lockd: unexpected unlock status: %d\n", status);
 648 die:
 649         return;
 650  retry_rebind:
 651         nlm_rebind_host(req->a_host);
 652  retry_unlock:
 653         rpc_restart_call(task);
 654 }
 655
 656 static const struct rpc_call_ops nlmclnt_unlock_ops = {
 657         .rpc_call_done = nlmclnt_unlock_callback,
 658         .rpc_release = nlmclnt_rpc_release,
 659 };
 660
 661 /*
 662  * Cancel a blocked lock request.
 663  * We always use an async RPC call for this in order not to hang a
 664  * process that has been Ctrl-C'ed.
 665  */
 666 static int nlmclnt_cancel(struct nlm_host *host, int block, struct file_lock *fl)
 667 {
 668         struct nlm_rqst *req;
 669         unsigned long   flags;
 670         sigset_t        oldset;
 671         int             status;
 672
 673         /* Block all signals while setting up call */
 674         spin_lock_irqsave(&current->sighand->siglock, flags);
 675         oldset = current->blocked;
 676         sigfillset(&current->blocked);
 677         recalc_sigpending();
 678         spin_unlock_irqrestore(&current->sighand->siglock, flags);
 679
 680         req = nlm_alloc_call(nlm_get_host(host));
 681         if (!req)
 682                 return -ENOMEM;
 683         req->a_flags = RPC_TASK_ASYNC;
 684
 685         nlmclnt_setlockargs(req, fl);
 686         req->a_args.block = block;
 687
 688         status = nlm_async_call(req, NLMPROC_CANCEL, &nlmclnt_cancel_ops);
 689
 690         spin_lock_irqsave(&current->sighand->siglock, flags);
 691         current->blocked = oldset;
 692         recalc_sigpending();
 693         spin_unlock_irqrestore(&current->sighand->siglock, flags);
 694
 695         return status;
 696 }
 697
 698 static void nlmclnt_cancel_callback(struct rpc_task *task, void *data)
 699 {
 700         struct nlm_rqst *req = data;
 701
 702         if (RPC_ASSASSINATED(task))
 703                 goto die;
 704
 705         if (task->tk_status < 0) {
 706                 dprintk("lockd: CANCEL call error %d, retrying.\n",
 707                                         task->tk_status);
 708                 goto retry_cancel;
 709         }
 710
 711         dprintk("lockd: cancel status %d (task %d)\n",
 712                         req->a_res.status, task->tk_pid);
 713
 714         switch (req->a_res.status) {
 715         case NLM_LCK_GRANTED:
 716         case NLM_LCK_DENIED_GRACE_PERIOD:
 717         case NLM_LCK_DENIED:
 718                 /* Everything's good */
 719                 break;
 720         case NLM_LCK_DENIED_NOLOCKS:
 721                 dprintk("lockd: CANCEL failed (server has no locks)\n");
 722                 goto retry_cancel;
 723         default:
 724                 printk(KERN_NOTICE "lockd: weird return %d for CANCEL call\n",
 725                         req->a_res.status);
 726         }
 727
 728 die:
 729         return;
 730
 731 retry_cancel:
 732         /* Don't ever retry more than 3 times */
 733         if (req->a_retries++ >= NLMCLNT_MAX_RETRIES)
 734                 goto die;
 735         nlm_rebind_host(req->a_host);
 736         rpc_restart_call(task);
 737         rpc_delay(task, 30 * HZ);
 738 }
 739
 740 static const struct rpc_call_ops nlmclnt_cancel_ops = {
 741         .rpc_call_done = nlmclnt_cancel_callback,
 742         .rpc_release = nlmclnt_rpc_release,
 743 };
 744
 745 /*
 746  * Convert an NLM status code to a generic kernel errno
 747  */
 748 static int
 749 nlm_stat_to_errno(u32 status)
 750 {
 751         switch(status) {
 752         case NLM_LCK_GRANTED:
 753                 return 0;
 754         case NLM_LCK_DENIED:
 755                 return -EAGAIN;
 756         case NLM_LCK_DENIED_NOLOCKS:
 757         case NLM_LCK_DENIED_GRACE_PERIOD:
 758                 return -ENOLCK;
 759         case NLM_LCK_BLOCKED:
 760                 printk(KERN_NOTICE "lockd: unexpected status NLM_BLOCKED\n");
 761                 return -ENOLCK;
 762 #ifdef CONFIG_LOCKD_V4
 763         case NLM_DEADLCK:
 764                 return -EDEADLK;
 765         case NLM_ROFS:
 766                 return -EROFS;
 767         case NLM_STALE_FH:
 768                 return -ESTALE;
 769         case NLM_FBIG:
 770                 return -EOVERFLOW;
 771         case NLM_FAILED:
 772                 return -ENOLCK;
 773 #endif
 774         }
 775         printk(KERN_NOTICE "lockd: unexpected server status %d\n", status);
 776         return -ENOLCK;
 777 }