SAFE public projects git trees. - safe/jmp/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 int      nlm_stat_to_errno(u32 stat);
  30 static void     nlmclnt_locks_init_private(struct file_lock *fl, struct nlm_host *host);
  31
  32 static const struct rpc_call_ops nlmclnt_unlock_ops;
  33 static const struct rpc_call_ops nlmclnt_cancel_ops;
  34
  35 /*
  36  * Cookie counter for NLM requests
  37  */
  38 static u32      nlm_cookie = 0x1234;
  39
  40 static inline void nlmclnt_next_cookie(struct nlm_cookie *c)
  41 {
  42         memcpy(c->data, &nlm_cookie, 4);
  43         memset(c->data+4, 0, 4);
  44         c->len=4;
  45         nlm_cookie++;
  46 }
  47
  48 static struct nlm_lockowner *nlm_get_lockowner(struct nlm_lockowner *lockowner)
  49 {
  50         atomic_inc(&lockowner->count);
  51         return lockowner;
  52 }
  53
  54 static void nlm_put_lockowner(struct nlm_lockowner *lockowner)
  55 {
  56         if (!atomic_dec_and_lock(&lockowner->count, &lockowner->host->h_lock))
  57                 return;
  58         list_del(&lockowner->list);
  59         spin_unlock(&lockowner->host->h_lock);
  60         nlm_release_host(lockowner->host);
  61         kfree(lockowner);
  62 }
  63
  64 static inline int nlm_pidbusy(struct nlm_host *host, uint32_t pid)
  65 {
  66         struct nlm_lockowner *lockowner;
  67         list_for_each_entry(lockowner, &host->h_lockowners, list) {
  68                 if (lockowner->pid == pid)
  69                         return -EBUSY;
  70         }
  71         return 0;
  72 }
  73
  74 static inline uint32_t __nlm_alloc_pid(struct nlm_host *host)
  75 {
  76         uint32_t res;
  77         do {
  78                 res = host->h_pidcount++;
  79         } while (nlm_pidbusy(host, res) < 0);
  80         return res;
  81 }
  82
  83 static struct nlm_lockowner *__nlm_find_lockowner(struct nlm_host *host, fl_owner_t owner)
  84 {
  85         struct nlm_lockowner *lockowner;
  86         list_for_each_entry(lockowner, &host->h_lockowners, list) {
  87                 if (lockowner->owner != owner)
  88                         continue;
  89                 return nlm_get_lockowner(lockowner);
  90         }
  91         return NULL;
  92 }
  93
  94 static struct nlm_lockowner *nlm_find_lockowner(struct nlm_host *host, fl_owner_t owner)
  95 {
  96         struct nlm_lockowner *res, *new = NULL;
  97
  98         spin_lock(&host->h_lock);
  99         res = __nlm_find_lockowner(host, owner);
 100         if (res == NULL) {
 101                 spin_unlock(&host->h_lock);
 102                 new = (struct nlm_lockowner *)kmalloc(sizeof(*new), GFP_KERNEL);
 103                 spin_lock(&host->h_lock);
 104                 res = __nlm_find_lockowner(host, owner);
 105                 if (res == NULL && new != NULL) {
 106                         res = new;
 107                         atomic_set(&new->count, 1);
 108                         new->owner = owner;
 109                         new->pid = __nlm_alloc_pid(host);
 110                         new->host = nlm_get_host(host);
 111                         list_add(&new->list, &host->h_lockowners);
 112                         new = NULL;
 113                 }
 114         }
 115         spin_unlock(&host->h_lock);
 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 nlmsvc_async_call(struct nlm_rqst *req, u32 proc, const struct rpc_call_ops *tk_ops)
 404 {
 405         struct nlm_host *host = req->a_host;
 406         struct rpc_clnt *clnt;
 407         struct rpc_message msg = {
 408                 .rpc_argp       = &req->a_args,
 409                 .rpc_resp       = &req->a_res,
 410         };
 411         int             status;
 412
 413         dprintk("lockd: call procedure %d on %s (async)\n",
 414                         (int)proc, host->h_name);
 415
 416         /* If we have no RPC client yet, create one. */
 417         if ((clnt = nlm_bind_host(host)) == NULL)
 418                 return -ENOLCK;
 419         msg.rpc_proc = &clnt->cl_procinfo[proc];
 420
 421         /* bootstrap and kick off the async RPC call */
 422         status = rpc_call_async(clnt, &msg, RPC_TASK_ASYNC, tk_ops, req);
 423
 424         return status;
 425 }
 426
 427 static int nlmclnt_async_call(struct nlm_rqst *req, u32 proc, const struct rpc_call_ops *tk_ops)
 428 {
 429         struct nlm_host *host = req->a_host;
 430         struct rpc_clnt *clnt;
 431         struct nlm_args *argp = &req->a_args;
 432         struct nlm_res  *resp = &req->a_res;
 433         struct rpc_message msg = {
 434                 .rpc_argp       = argp,
 435                 .rpc_resp       = resp,
 436         };
 437         int             status;
 438
 439         dprintk("lockd: call procedure %d on %s (async)\n",
 440                         (int)proc, host->h_name);
 441
 442         /* If we have no RPC client yet, create one. */
 443         if ((clnt = nlm_bind_host(host)) == NULL)
 444                 return -ENOLCK;
 445         msg.rpc_proc = &clnt->cl_procinfo[proc];
 446
 447         /* Increment host refcount */
 448         nlm_get_host(host);
 449         /* bootstrap and kick off the async RPC call */
 450         status = rpc_call_async(clnt, &msg, RPC_TASK_ASYNC, tk_ops, req);
 451         if (status < 0)
 452                 nlm_release_host(host);
 453         return status;
 454 }
 455
 456 /*
 457  * TEST for the presence of a conflicting lock
 458  */
 459 static int
 460 nlmclnt_test(struct nlm_rqst *req, struct file_lock *fl)
 461 {
 462         int     status;
 463
 464         status = nlmclnt_call(req, NLMPROC_TEST);
 465         nlmclnt_release_lockargs(req);
 466         if (status < 0)
 467                 return status;
 468
 469         status = req->a_res.status;
 470         if (status == NLM_LCK_GRANTED) {
 471                 fl->fl_type = F_UNLCK;
 472         } if (status == NLM_LCK_DENIED) {
 473                 /*
 474                  * Report the conflicting lock back to the application.
 475                  */
 476                 locks_copy_lock(fl, &req->a_res.lock.fl);
 477                 fl->fl_pid = 0;
 478         } else {
 479                 return nlm_stat_to_errno(req->a_res.status);
 480         }
 481
 482         return 0;
 483 }
 484
 485 static void nlmclnt_locks_copy_lock(struct file_lock *new, struct file_lock *fl)
 486 {
 487         memcpy(&new->fl_u.nfs_fl, &fl->fl_u.nfs_fl, sizeof(new->fl_u.nfs_fl));
 488         nlm_get_lockowner(new->fl_u.nfs_fl.owner);
 489 }
 490
 491 static void nlmclnt_locks_release_private(struct file_lock *fl)
 492 {
 493         nlm_put_lockowner(fl->fl_u.nfs_fl.owner);
 494         fl->fl_ops = NULL;
 495 }
 496
 497 static struct file_lock_operations nlmclnt_lock_ops = {
 498         .fl_copy_lock = nlmclnt_locks_copy_lock,
 499         .fl_release_private = nlmclnt_locks_release_private,
 500 };
 501
 502 static void nlmclnt_locks_init_private(struct file_lock *fl, struct nlm_host *host)
 503 {
 504         BUG_ON(fl->fl_ops != NULL);
 505         fl->fl_u.nfs_fl.state = 0;
 506         fl->fl_u.nfs_fl.flags = 0;
 507         fl->fl_u.nfs_fl.owner = nlm_find_lockowner(host, fl->fl_owner);
 508         fl->fl_ops = &nlmclnt_lock_ops;
 509 }
 510
 511 static void do_vfs_lock(struct file_lock *fl)
 512 {
 513         int res = 0;
 514         switch (fl->fl_flags & (FL_POSIX|FL_FLOCK)) {
 515                 case FL_POSIX:
 516                         res = posix_lock_file_wait(fl->fl_file, fl);
 517                         break;
 518                 case FL_FLOCK:
 519                         res = flock_lock_file_wait(fl->fl_file, fl);
 520                         break;
 521                 default:
 522                         BUG();
 523         }
 524         if (res < 0)
 525                 printk(KERN_WARNING "%s: VFS is out of sync with lock manager!\n",
 526                                 __FUNCTION__);
 527 }
 528
 529 /*
 530  * LOCK: Try to create a lock
 531  *
 532  *                      Programmer Harassment Alert
 533  *
 534  * When given a blocking lock request in a sync RPC call, the HPUX lockd
 535  * will faithfully return LCK_BLOCKED but never cares to notify us when
 536  * the lock could be granted. This way, our local process could hang
 537  * around forever waiting for the callback.
 538  *
 539  *  Solution A: Implement busy-waiting
 540  *  Solution B: Use the async version of the call (NLM_LOCK_{MSG,RES})
 541  *
 542  * For now I am implementing solution A, because I hate the idea of
 543  * re-implementing lockd for a third time in two months. The async
 544  * calls shouldn't be too hard to do, however.
 545  *
 546  * This is one of the lovely things about standards in the NFS area:
 547  * they're so soft and squishy you can't really blame HP for doing this.
 548  */
 549 static int
 550 nlmclnt_lock(struct nlm_rqst *req, struct file_lock *fl)
 551 {
 552         struct nlm_host *host = req->a_host;
 553         struct nlm_res  *resp = &req->a_res;
 554         long timeout;
 555         int status;
 556
 557         if (!host->h_monitored && nsm_monitor(host) < 0) {
 558                 printk(KERN_NOTICE "lockd: failed to monitor %s\n",
 559                                         host->h_name);
 560                 status = -ENOLCK;
 561                 goto out;
 562         }
 563
 564         if (req->a_args.block) {
 565                 status = nlmclnt_prepare_block(req, host, fl);
 566                 if (status < 0)
 567                         goto out;
 568         }
 569         for(;;) {
 570                 status = nlmclnt_call(req, NLMPROC_LOCK);
 571                 if (status < 0)
 572                         goto out_unblock;
 573                 if (resp->status != NLM_LCK_BLOCKED)
 574                         break;
 575                 /* Wait on an NLM blocking lock */
 576                 timeout = nlmclnt_block(req, NLMCLNT_POLL_TIMEOUT);
 577                 /* Did a reclaimer thread notify us of a server reboot? */
 578                 if (resp->status ==  NLM_LCK_DENIED_GRACE_PERIOD)
 579                         continue;
 580                 if (resp->status != NLM_LCK_BLOCKED)
 581                         break;
 582                 if (timeout >= 0)
 583                         continue;
 584                 /* We were interrupted. Send a CANCEL request to the server
 585                  * and exit
 586                  */
 587                 status = (int)timeout;
 588                 goto out_unblock;
 589         }
 590
 591         if (resp->status == NLM_LCK_GRANTED) {
 592                 fl->fl_u.nfs_fl.state = host->h_state;
 593                 fl->fl_u.nfs_fl.flags |= NFS_LCK_GRANTED;
 594                 fl->fl_flags |= FL_SLEEP;
 595                 do_vfs_lock(fl);
 596         }
 597         status = nlm_stat_to_errno(resp->status);
 598 out_unblock:
 599         nlmclnt_finish_block(req);
 600         /* Cancel the blocked request if it is still pending */
 601         if (resp->status == NLM_LCK_BLOCKED)
 602                 nlmclnt_cancel(host, fl);
 603 out:
 604         nlmclnt_release_lockargs(req);
 605         return status;
 606 }
 607
 608 /*
 609  * RECLAIM: Try to reclaim a lock
 610  */
 611 int
 612 nlmclnt_reclaim(struct nlm_host *host, struct file_lock *fl)
 613 {
 614         struct nlm_rqst reqst, *req;
 615         int             status;
 616
 617         req = &reqst;
 618         memset(req, 0, sizeof(*req));
 619         locks_init_lock(&req->a_args.lock.fl);
 620         locks_init_lock(&req->a_res.lock.fl);
 621         req->a_host  = host;
 622         req->a_flags = 0;
 623
 624         /* Set up the argument struct */
 625         nlmclnt_setlockargs(req, fl);
 626         req->a_args.reclaim = 1;
 627
 628         if ((status = nlmclnt_call(req, NLMPROC_LOCK)) >= 0
 629          && req->a_res.status == NLM_LCK_GRANTED)
 630                 return 0;
 631
 632         printk(KERN_WARNING "lockd: failed to reclaim lock for pid %d "
 633                                 "(errno %d, status %d)\n", fl->fl_pid,
 634                                 status, req->a_res.status);
 635
 636         /*
 637          * FIXME: This is a serious failure. We can
 638          *
 639          *  a.  Ignore the problem
 640          *  b.  Send the owning process some signal (Linux doesn't have
 641          *      SIGLOST, though...)
 642          *  c.  Retry the operation
 643          *
 644          * Until someone comes up with a simple implementation
 645          * for b or c, I'll choose option a.
 646          */
 647
 648         return -ENOLCK;
 649 }
 650
 651 /*
 652  * UNLOCK: remove an existing lock
 653  */
 654 static int
 655 nlmclnt_unlock(struct nlm_rqst *req, struct file_lock *fl)
 656 {
 657         struct nlm_res  *resp = &req->a_res;
 658         int             status;
 659
 660         /* Clean the GRANTED flag now so the lock doesn't get
 661          * reclaimed while we're stuck in the unlock call. */
 662         fl->fl_u.nfs_fl.flags &= ~NFS_LCK_GRANTED;
 663
 664         if (req->a_flags & RPC_TASK_ASYNC) {
 665                 status = nlmclnt_async_call(req, NLMPROC_UNLOCK,
 666                                         &nlmclnt_unlock_ops);
 667                 /* Hrmf... Do the unlock early since locks_remove_posix()
 668                  * really expects us to free the lock synchronously */
 669                 do_vfs_lock(fl);
 670                 if (status < 0) {
 671                         nlmclnt_release_lockargs(req);
 672                         kfree(req);
 673                 }
 674                 return status;
 675         }
 676
 677         status = nlmclnt_call(req, NLMPROC_UNLOCK);
 678         nlmclnt_release_lockargs(req);
 679         if (status < 0)
 680                 return status;
 681
 682         do_vfs_lock(fl);
 683         if (resp->status == NLM_LCK_GRANTED)
 684                 return 0;
 685
 686         if (resp->status != NLM_LCK_DENIED_NOLOCKS)
 687                 printk("lockd: unexpected unlock status: %d\n", resp->status);
 688
 689         /* What to do now? I'm out of my depth... */
 690
 691         return -ENOLCK;
 692 }
 693
 694 static void nlmclnt_unlock_callback(struct rpc_task *task, void *data)
 695 {
 696         struct nlm_rqst *req = data;
 697         int             status = req->a_res.status;
 698
 699         if (RPC_ASSASSINATED(task))
 700                 goto die;
 701
 702         if (task->tk_status < 0) {
 703                 dprintk("lockd: unlock failed (err = %d)\n", -task->tk_status);
 704                 goto retry_rebind;
 705         }
 706         if (status == NLM_LCK_DENIED_GRACE_PERIOD) {
 707                 rpc_delay(task, NLMCLNT_GRACE_WAIT);
 708                 goto retry_unlock;
 709         }
 710         if (status != NLM_LCK_GRANTED)
 711                 printk(KERN_WARNING "lockd: unexpected unlock status: %d\n", status);
 712 die:
 713         nlm_release_host(req->a_host);
 714         nlmclnt_release_lockargs(req);
 715         kfree(req);
 716         return;
 717  retry_rebind:
 718         nlm_rebind_host(req->a_host);
 719  retry_unlock:
 720         rpc_restart_call(task);
 721 }
 722
 723 static const struct rpc_call_ops nlmclnt_unlock_ops = {
 724         .rpc_call_done = nlmclnt_unlock_callback,
 725 };
 726
 727 /*
 728  * Cancel a blocked lock request.
 729  * We always use an async RPC call for this in order not to hang a
 730  * process that has been Ctrl-C'ed.
 731  */
 732 int
 733 nlmclnt_cancel(struct nlm_host *host, struct file_lock *fl)
 734 {
 735         struct nlm_rqst *req;
 736         unsigned long   flags;
 737         sigset_t        oldset;
 738         int             status;
 739
 740         /* Block all signals while setting up call */
 741         spin_lock_irqsave(&current->sighand->siglock, flags);
 742         oldset = current->blocked;
 743         sigfillset(&current->blocked);
 744         recalc_sigpending();
 745         spin_unlock_irqrestore(&current->sighand->siglock, flags);
 746
 747         req = nlmclnt_alloc_call();
 748         if (!req)
 749                 return -ENOMEM;
 750         req->a_host  = host;
 751         req->a_flags = RPC_TASK_ASYNC;
 752
 753         nlmclnt_setlockargs(req, fl);
 754
 755         status = nlmclnt_async_call(req, NLMPROC_CANCEL, &nlmclnt_cancel_ops);
 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 nlmclnt_cancel_callback(struct rpc_task *task, void *data)
 770 {
 771         struct nlm_rqst *req = data;
 772
 773         if (RPC_ASSASSINATED(task))
 774                 goto die;
 775
 776         if (task->tk_status < 0) {
 777                 dprintk("lockd: CANCEL call error %d, retrying.\n",
 778                                         task->tk_status);
 779                 goto retry_cancel;
 780         }
 781
 782         dprintk("lockd: cancel status %d (task %d)\n",
 783                         req->a_res.status, task->tk_pid);
 784
 785         switch (req->a_res.status) {
 786         case NLM_LCK_GRANTED:
 787         case NLM_LCK_DENIED_GRACE_PERIOD:
 788                 /* Everything's good */
 789                 break;
 790         case NLM_LCK_DENIED_NOLOCKS:
 791                 dprintk("lockd: CANCEL failed (server has no locks)\n");
 792                 goto retry_cancel;
 793         default:
 794                 printk(KERN_NOTICE "lockd: weird return %d for CANCEL call\n",
 795                         req->a_res.status);
 796         }
 797
 798 die:
 799         nlm_release_host(req->a_host);
 800         nlmclnt_release_lockargs(req);
 801         kfree(req);
 802         return;
 803
 804 retry_cancel:
 805         nlm_rebind_host(req->a_host);
 806         rpc_restart_call(task);
 807         rpc_delay(task, 30 * HZ);
 808 }
 809
 810 static const struct rpc_call_ops nlmclnt_cancel_ops = {
 811         .rpc_call_done = nlmclnt_cancel_callback,
 812 };
 813
 814 /*
 815  * Convert an NLM status code to a generic kernel errno
 816  */
 817 static int
 818 nlm_stat_to_errno(u32 status)
 819 {
 820         switch(status) {
 821         case NLM_LCK_GRANTED:
 822                 return 0;
 823         case NLM_LCK_DENIED:
 824                 return -EAGAIN;
 825         case NLM_LCK_DENIED_NOLOCKS:
 826         case NLM_LCK_DENIED_GRACE_PERIOD:
 827                 return -ENOLCK;
 828         case NLM_LCK_BLOCKED:
 829                 printk(KERN_NOTICE "lockd: unexpected status NLM_BLOCKED\n");
 830                 return -ENOLCK;
 831 #ifdef CONFIG_LOCKD_V4
 832         case NLM_DEADLCK:
 833                 return -EDEADLK;
 834         case NLM_ROFS:
 835                 return -EROFS;
 836         case NLM_STALE_FH:
 837                 return -ESTALE;
 838         case NLM_FBIG:
 839                 return -EOVERFLOW;
 840         case NLM_FAILED:
 841                 return -ENOLCK;
 842 #endif
 843         }
 844         printk(KERN_NOTICE "lockd: unexpected server status %d\n", status);
 845         return -ENOLCK;
 846 }