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  = sprintf(req->a_owner, "%d@%s",
 136                                 current->pid, system_utsname.nodename);
 137         locks_copy_lock(&lock->fl, fl);
 138 }
 139
 140 static void nlmclnt_release_lockargs(struct nlm_rqst *req)
 141 {
 142         struct file_lock *fl = &req->a_args.lock.fl;
 143
 144         if (fl->fl_ops && fl->fl_ops->fl_release_private)
 145                 fl->fl_ops->fl_release_private(fl);
 146 }
 147
 148 /*
 149  * Initialize arguments for GRANTED call. The nlm_rqst structure
 150  * has been cleared already.
 151  */
 152 int
 153 nlmclnt_setgrantargs(struct nlm_rqst *call, struct nlm_lock *lock)
 154 {
 155         locks_copy_lock(&call->a_args.lock.fl, &lock->fl);
 156         memcpy(&call->a_args.lock.fh, &lock->fh, sizeof(call->a_args.lock.fh));
 157         call->a_args.lock.caller = system_utsname.nodename;
 158         call->a_args.lock.oh.len = lock->oh.len;
 159
 160         /* set default data area */
 161         call->a_args.lock.oh.data = call->a_owner;
 162
 163         if (lock->oh.len > NLMCLNT_OHSIZE) {
 164                 void *data = kmalloc(lock->oh.len, GFP_KERNEL);
 165                 if (!data) {
 166                         nlmclnt_freegrantargs(call);
 167                         return 0;
 168                 }
 169                 call->a_args.lock.oh.data = (u8 *) data;
 170         }
 171
 172         memcpy(call->a_args.lock.oh.data, lock->oh.data, lock->oh.len);
 173         return 1;
 174 }
 175
 176 void
 177 nlmclnt_freegrantargs(struct nlm_rqst *call)
 178 {
 179         struct file_lock *fl = &call->a_args.lock.fl;
 180         /*
 181          * Check whether we allocated memory for the owner.
 182          */
 183         if (call->a_args.lock.oh.data != (u8 *) call->a_owner) {
 184                 kfree(call->a_args.lock.oh.data);
 185         }
 186         if (fl->fl_ops && fl->fl_ops->fl_release_private)
 187                 fl->fl_ops->fl_release_private(fl);
 188 }
 189
 190 /*
 191  * This is the main entry point for the NLM client.
 192  */
 193 int
 194 nlmclnt_proc(struct inode *inode, int cmd, struct file_lock *fl)
 195 {
 196         struct nfs_server       *nfssrv = NFS_SERVER(inode);
 197         struct nlm_host         *host;
 198         struct nlm_rqst         reqst, *call = &reqst;
 199         sigset_t                oldset;
 200         unsigned long           flags;
 201         int                     status, proto, vers;
 202
 203         vers = (NFS_PROTO(inode)->version == 3) ? 4 : 1;
 204         if (NFS_PROTO(inode)->version > 3) {
 205                 printk(KERN_NOTICE "NFSv4 file locking not implemented!\n");
 206                 return -ENOLCK;
 207         }
 208
 209         /* Retrieve transport protocol from NFS client */
 210         proto = NFS_CLIENT(inode)->cl_xprt->prot;
 211
 212         if (!(host = nlmclnt_lookup_host(NFS_ADDR(inode), proto, vers)))
 213                 return -ENOLCK;
 214
 215         /* Create RPC client handle if not there, and copy soft
 216          * and intr flags from NFS client. */
 217         if (host->h_rpcclnt == NULL) {
 218                 struct rpc_clnt *clnt;
 219
 220                 /* Bind an rpc client to this host handle (does not
 221                  * perform a portmapper lookup) */
 222                 if (!(clnt = nlm_bind_host(host))) {
 223                         status = -ENOLCK;
 224                         goto done;
 225                 }
 226                 clnt->cl_softrtry = nfssrv->client->cl_softrtry;
 227                 clnt->cl_intr = nfssrv->client->cl_intr;
 228         }
 229
 230         /* Keep the old signal mask */
 231         spin_lock_irqsave(&current->sighand->siglock, flags);
 232         oldset = current->blocked;
 233
 234         /* If we're cleaning up locks because the process is exiting,
 235          * perform the RPC call asynchronously. */
 236         if ((IS_SETLK(cmd) || IS_SETLKW(cmd))
 237             && fl->fl_type == F_UNLCK
 238             && (current->flags & PF_EXITING)) {
 239                 sigfillset(&current->blocked);  /* Mask all signals */
 240                 recalc_sigpending();
 241                 spin_unlock_irqrestore(&current->sighand->siglock, flags);
 242
 243                 call = nlmclnt_alloc_call();
 244                 if (!call) {
 245                         status = -ENOMEM;
 246                         goto out_restore;
 247                 }
 248                 call->a_flags = RPC_TASK_ASYNC;
 249         } else {
 250                 spin_unlock_irqrestore(&current->sighand->siglock, flags);
 251                 memset(call, 0, sizeof(*call));
 252                 locks_init_lock(&call->a_args.lock.fl);
 253                 locks_init_lock(&call->a_res.lock.fl);
 254         }
 255         call->a_host = host;
 256
 257         nlmclnt_locks_init_private(fl, host);
 258
 259         /* Set up the argument struct */
 260         nlmclnt_setlockargs(call, fl);
 261
 262         if (IS_SETLK(cmd) || IS_SETLKW(cmd)) {
 263                 if (fl->fl_type != F_UNLCK) {
 264                         call->a_args.block = IS_SETLKW(cmd) ? 1 : 0;
 265                         status = nlmclnt_lock(call, fl);
 266                 } else
 267                         status = nlmclnt_unlock(call, fl);
 268         } else if (IS_GETLK(cmd))
 269                 status = nlmclnt_test(call, fl);
 270         else
 271                 status = -EINVAL;
 272
 273  out_restore:
 274         spin_lock_irqsave(&current->sighand->siglock, flags);
 275         current->blocked = oldset;
 276         recalc_sigpending();
 277         spin_unlock_irqrestore(&current->sighand->siglock, flags);
 278
 279 done:
 280         dprintk("lockd: clnt proc returns %d\n", status);
 281         nlm_release_host(host);
 282         return status;
 283 }
 284 EXPORT_SYMBOL(nlmclnt_proc);
 285
 286 /*
 287  * Allocate an NLM RPC call struct
 288  */
 289 struct nlm_rqst *
 290 nlmclnt_alloc_call(void)
 291 {
 292         struct nlm_rqst *call;
 293
 294         while (!signalled()) {
 295                 call = (struct nlm_rqst *) kmalloc(sizeof(struct nlm_rqst), GFP_KERNEL);
 296                 if (call) {
 297                         memset(call, 0, sizeof(*call));
 298                         locks_init_lock(&call->a_args.lock.fl);
 299                         locks_init_lock(&call->a_res.lock.fl);
 300                         return call;
 301                 }
 302                 printk("nlmclnt_alloc_call: failed, waiting for memory\n");
 303                 schedule_timeout_interruptible(5*HZ);
 304         }
 305         return NULL;
 306 }
 307
 308 static int nlm_wait_on_grace(wait_queue_head_t *queue)
 309 {
 310         DEFINE_WAIT(wait);
 311         int status = -EINTR;
 312
 313         prepare_to_wait(queue, &wait, TASK_INTERRUPTIBLE);
 314         if (!signalled ()) {
 315                 schedule_timeout(NLMCLNT_GRACE_WAIT);
 316                 try_to_freeze();
 317                 if (!signalled ())
 318                         status = 0;
 319         }
 320         finish_wait(queue, &wait);
 321         return status;
 322 }
 323
 324 /*
 325  * Generic NLM call
 326  */
 327 static int
 328 nlmclnt_call(struct nlm_rqst *req, u32 proc)
 329 {
 330         struct nlm_host *host = req->a_host;
 331         struct rpc_clnt *clnt;
 332         struct nlm_args *argp = &req->a_args;
 333         struct nlm_res  *resp = &req->a_res;
 334         struct rpc_message msg = {
 335                 .rpc_argp       = argp,
 336                 .rpc_resp       = resp,
 337         };
 338         int             status;
 339
 340         dprintk("lockd: call procedure %d on %s\n",
 341                         (int)proc, host->h_name);
 342
 343         do {
 344                 if (host->h_reclaiming && !argp->reclaim)
 345                         goto in_grace_period;
 346
 347                 /* If we have no RPC client yet, create one. */
 348                 if ((clnt = nlm_bind_host(host)) == NULL)
 349                         return -ENOLCK;
 350                 msg.rpc_proc = &clnt->cl_procinfo[proc];
 351
 352                 /* Perform the RPC call. If an error occurs, try again */
 353                 if ((status = rpc_call_sync(clnt, &msg, 0)) < 0) {
 354                         dprintk("lockd: rpc_call returned error %d\n", -status);
 355                         switch (status) {
 356                         case -EPROTONOSUPPORT:
 357                                 status = -EINVAL;
 358                                 break;
 359                         case -ECONNREFUSED:
 360                         case -ETIMEDOUT:
 361                         case -ENOTCONN:
 362                                 nlm_rebind_host(host);
 363                                 status = -EAGAIN;
 364                                 break;
 365                         case -ERESTARTSYS:
 366                                 return signalled () ? -EINTR : status;
 367                         default:
 368                                 break;
 369                         }
 370                         break;
 371                 } else
 372                 if (resp->status == NLM_LCK_DENIED_GRACE_PERIOD) {
 373                         dprintk("lockd: server in grace period\n");
 374                         if (argp->reclaim) {
 375                                 printk(KERN_WARNING
 376                                      "lockd: spurious grace period reject?!\n");
 377                                 return -ENOLCK;
 378                         }
 379                 } else {
 380                         if (!argp->reclaim) {
 381                                 /* We appear to be out of the grace period */
 382                                 wake_up_all(&host->h_gracewait);
 383                         }
 384                         dprintk("lockd: server returns status %d\n", resp->status);
 385                         return 0;       /* Okay, call complete */
 386                 }
 387
 388 in_grace_period:
 389                 /*
 390                  * The server has rebooted and appears to be in the grace
 391                  * period during which locks are only allowed to be
 392                  * reclaimed.
 393                  * We can only back off and try again later.
 394                  */
 395                 status = nlm_wait_on_grace(&host->h_gracewait);
 396         } while (status == 0);
 397
 398         return status;
 399 }
 400
 401 /*
 402  * Generic NLM call, async version.
 403  */
 404 int nlmsvc_async_call(struct nlm_rqst *req, u32 proc, const struct rpc_call_ops *tk_ops)
 405 {
 406         struct nlm_host *host = req->a_host;
 407         struct rpc_clnt *clnt;
 408         struct rpc_message msg = {
 409                 .rpc_argp       = &req->a_args,
 410                 .rpc_resp       = &req->a_res,
 411         };
 412         int             status;
 413
 414         dprintk("lockd: call procedure %d on %s (async)\n",
 415                         (int)proc, host->h_name);
 416
 417         /* If we have no RPC client yet, create one. */
 418         if ((clnt = nlm_bind_host(host)) == NULL)
 419                 return -ENOLCK;
 420         msg.rpc_proc = &clnt->cl_procinfo[proc];
 421
 422         /* bootstrap and kick off the async RPC call */
 423         status = rpc_call_async(clnt, &msg, RPC_TASK_ASYNC, tk_ops, req);
 424
 425         return status;
 426 }
 427
 428 static int nlmclnt_async_call(struct nlm_rqst *req, u32 proc, const struct rpc_call_ops *tk_ops)
 429 {
 430         struct nlm_host *host = req->a_host;
 431         struct rpc_clnt *clnt;
 432         struct nlm_args *argp = &req->a_args;
 433         struct nlm_res  *resp = &req->a_res;
 434         struct rpc_message msg = {
 435                 .rpc_argp       = argp,
 436                 .rpc_resp       = resp,
 437         };
 438         int             status;
 439
 440         dprintk("lockd: call procedure %d on %s (async)\n",
 441                         (int)proc, host->h_name);
 442
 443         /* If we have no RPC client yet, create one. */
 444         if ((clnt = nlm_bind_host(host)) == NULL)
 445                 return -ENOLCK;
 446         msg.rpc_proc = &clnt->cl_procinfo[proc];
 447
 448         /* Increment host refcount */
 449         nlm_get_host(host);
 450         /* bootstrap and kick off the async RPC call */
 451         status = rpc_call_async(clnt, &msg, RPC_TASK_ASYNC, tk_ops, req);
 452         if (status < 0)
 453                 nlm_release_host(host);
 454         return status;
 455 }
 456
 457 /*
 458  * TEST for the presence of a conflicting lock
 459  */
 460 static int
 461 nlmclnt_test(struct nlm_rqst *req, struct file_lock *fl)
 462 {
 463         int     status;
 464
 465         status = nlmclnt_call(req, NLMPROC_TEST);
 466         nlmclnt_release_lockargs(req);
 467         if (status < 0)
 468                 return status;
 469
 470         status = req->a_res.status;
 471         if (status == NLM_LCK_GRANTED) {
 472                 fl->fl_type = F_UNLCK;
 473         } if (status == NLM_LCK_DENIED) {
 474                 /*
 475                  * Report the conflicting lock back to the application.
 476                  */
 477                 locks_copy_lock(fl, &req->a_res.lock.fl);
 478                 fl->fl_pid = 0;
 479         } else {
 480                 return nlm_stat_to_errno(req->a_res.status);
 481         }
 482
 483         return 0;
 484 }
 485
 486 static void nlmclnt_locks_copy_lock(struct file_lock *new, struct file_lock *fl)
 487 {
 488         memcpy(&new->fl_u.nfs_fl, &fl->fl_u.nfs_fl, sizeof(new->fl_u.nfs_fl));
 489         nlm_get_lockowner(new->fl_u.nfs_fl.owner);
 490 }
 491
 492 static void nlmclnt_locks_release_private(struct file_lock *fl)
 493 {
 494         nlm_put_lockowner(fl->fl_u.nfs_fl.owner);
 495         fl->fl_ops = NULL;
 496 }
 497
 498 static struct file_lock_operations nlmclnt_lock_ops = {
 499         .fl_copy_lock = nlmclnt_locks_copy_lock,
 500         .fl_release_private = nlmclnt_locks_release_private,
 501 };
 502
 503 static void nlmclnt_locks_init_private(struct file_lock *fl, struct nlm_host *host)
 504 {
 505         BUG_ON(fl->fl_ops != NULL);
 506         fl->fl_u.nfs_fl.state = 0;
 507         fl->fl_u.nfs_fl.flags = 0;
 508         fl->fl_u.nfs_fl.owner = nlm_find_lockowner(host, fl->fl_owner);
 509         fl->fl_ops = &nlmclnt_lock_ops;
 510 }
 511
 512 static void do_vfs_lock(struct file_lock *fl)
 513 {
 514         int res = 0;
 515         switch (fl->fl_flags & (FL_POSIX|FL_FLOCK)) {
 516                 case FL_POSIX:
 517                         res = posix_lock_file_wait(fl->fl_file, fl);
 518                         break;
 519                 case FL_FLOCK:
 520                         res = flock_lock_file_wait(fl->fl_file, fl);
 521                         break;
 522                 default:
 523                         BUG();
 524         }
 525         if (res < 0)
 526                 printk(KERN_WARNING "%s: VFS is out of sync with lock manager!\n",
 527                                 __FUNCTION__);
 528 }
 529
 530 /*
 531  * LOCK: Try to create a lock
 532  *
 533  *                      Programmer Harassment Alert
 534  *
 535  * When given a blocking lock request in a sync RPC call, the HPUX lockd
 536  * will faithfully return LCK_BLOCKED but never cares to notify us when
 537  * the lock could be granted. This way, our local process could hang
 538  * around forever waiting for the callback.
 539  *
 540  *  Solution A: Implement busy-waiting
 541  *  Solution B: Use the async version of the call (NLM_LOCK_{MSG,RES})
 542  *
 543  * For now I am implementing solution A, because I hate the idea of
 544  * re-implementing lockd for a third time in two months. The async
 545  * calls shouldn't be too hard to do, however.
 546  *
 547  * This is one of the lovely things about standards in the NFS area:
 548  * they're so soft and squishy you can't really blame HP for doing this.
 549  */
 550 static int
 551 nlmclnt_lock(struct nlm_rqst *req, struct file_lock *fl)
 552 {
 553         struct nlm_host *host = req->a_host;
 554         struct nlm_res  *resp = &req->a_res;
 555         long timeout;
 556         int status;
 557
 558         if (!host->h_monitored && nsm_monitor(host) < 0) {
 559                 printk(KERN_NOTICE "lockd: failed to monitor %s\n",
 560                                         host->h_name);
 561                 status = -ENOLCK;
 562                 goto out;
 563         }
 564
 565         if (req->a_args.block) {
 566                 status = nlmclnt_prepare_block(req, host, fl);
 567                 if (status < 0)
 568                         goto out;
 569         }
 570         for(;;) {
 571                 status = nlmclnt_call(req, NLMPROC_LOCK);
 572                 if (status < 0)
 573                         goto out_unblock;
 574                 if (resp->status != NLM_LCK_BLOCKED)
 575                         break;
 576                 /* Wait on an NLM blocking lock */
 577                 timeout = nlmclnt_block(req, NLMCLNT_POLL_TIMEOUT);
 578                 /* Did a reclaimer thread notify us of a server reboot? */
 579                 if (resp->status ==  NLM_LCK_DENIED_GRACE_PERIOD)
 580                         continue;
 581                 if (resp->status != NLM_LCK_BLOCKED)
 582                         break;
 583                 if (timeout >= 0)
 584                         continue;
 585                 /* We were interrupted. Send a CANCEL request to the server
 586                  * and exit
 587                  */
 588                 status = (int)timeout;
 589                 goto out_unblock;
 590         }
 591
 592         if (resp->status == NLM_LCK_GRANTED) {
 593                 fl->fl_u.nfs_fl.state = host->h_state;
 594                 fl->fl_u.nfs_fl.flags |= NFS_LCK_GRANTED;
 595                 fl->fl_flags |= FL_SLEEP;
 596                 do_vfs_lock(fl);
 597         }
 598         status = nlm_stat_to_errno(resp->status);
 599 out_unblock:
 600         nlmclnt_finish_block(req);
 601         /* Cancel the blocked request if it is still pending */
 602         if (resp->status == NLM_LCK_BLOCKED)
 603                 nlmclnt_cancel(host, req->a_args.block, fl);
 604 out:
 605         nlmclnt_release_lockargs(req);
 606         return status;
 607 }
 608
 609 /*
 610  * RECLAIM: Try to reclaim a lock
 611  */
 612 int
 613 nlmclnt_reclaim(struct nlm_host *host, struct file_lock *fl)
 614 {
 615         struct nlm_rqst reqst, *req;
 616         int             status;
 617
 618         req = &reqst;
 619         memset(req, 0, sizeof(*req));
 620         locks_init_lock(&req->a_args.lock.fl);
 621         locks_init_lock(&req->a_res.lock.fl);
 622         req->a_host  = host;
 623         req->a_flags = 0;
 624
 625         /* Set up the argument struct */
 626         nlmclnt_setlockargs(req, fl);
 627         req->a_args.reclaim = 1;
 628
 629         if ((status = nlmclnt_call(req, NLMPROC_LOCK)) >= 0
 630          && req->a_res.status == NLM_LCK_GRANTED)
 631                 return 0;
 632
 633         printk(KERN_WARNING "lockd: failed to reclaim lock for pid %d "
 634                                 "(errno %d, status %d)\n", fl->fl_pid,
 635                                 status, req->a_res.status);
 636
 637         /*
 638          * FIXME: This is a serious failure. We can
 639          *
 640          *  a.  Ignore the problem
 641          *  b.  Send the owning process some signal (Linux doesn't have
 642          *      SIGLOST, though...)
 643          *  c.  Retry the operation
 644          *
 645          * Until someone comes up with a simple implementation
 646          * for b or c, I'll choose option a.
 647          */
 648
 649         return -ENOLCK;
 650 }
 651
 652 /*
 653  * UNLOCK: remove an existing lock
 654  */
 655 static int
 656 nlmclnt_unlock(struct nlm_rqst *req, struct file_lock *fl)
 657 {
 658         struct nlm_res  *resp = &req->a_res;
 659         int             status;
 660
 661         /* Clean the GRANTED flag now so the lock doesn't get
 662          * reclaimed while we're stuck in the unlock call. */
 663         fl->fl_u.nfs_fl.flags &= ~NFS_LCK_GRANTED;
 664
 665         /*
 666          * Note: the server is supposed to either grant us the unlock
 667          * request, or to deny it with NLM_LCK_DENIED_GRACE_PERIOD. In either
 668          * case, we want to unlock.
 669          */
 670         do_vfs_lock(fl);
 671
 672         if (req->a_flags & RPC_TASK_ASYNC) {
 673                 status = nlmclnt_async_call(req, NLMPROC_UNLOCK,
 674                                         &nlmclnt_unlock_ops);
 675                 /* Hrmf... Do the unlock early since locks_remove_posix()
 676                  * really expects us to free the lock synchronously */
 677                 if (status < 0) {
 678                         nlmclnt_release_lockargs(req);
 679                         kfree(req);
 680                 }
 681                 return status;
 682         }
 683
 684         status = nlmclnt_call(req, NLMPROC_UNLOCK);
 685         nlmclnt_release_lockargs(req);
 686         if (status < 0)
 687                 return status;
 688
 689         if (resp->status == NLM_LCK_GRANTED)
 690                 return 0;
 691
 692         if (resp->status != NLM_LCK_DENIED_NOLOCKS)
 693                 printk("lockd: unexpected unlock status: %d\n", resp->status);
 694
 695         /* What to do now? I'm out of my depth... */
 696
 697         return -ENOLCK;
 698 }
 699
 700 static void nlmclnt_unlock_callback(struct rpc_task *task, void *data)
 701 {
 702         struct nlm_rqst *req = data;
 703         int             status = req->a_res.status;
 704
 705         if (RPC_ASSASSINATED(task))
 706                 goto die;
 707
 708         if (task->tk_status < 0) {
 709                 dprintk("lockd: unlock failed (err = %d)\n", -task->tk_status);
 710                 goto retry_rebind;
 711         }
 712         if (status == NLM_LCK_DENIED_GRACE_PERIOD) {
 713                 rpc_delay(task, NLMCLNT_GRACE_WAIT);
 714                 goto retry_unlock;
 715         }
 716         if (status != NLM_LCK_GRANTED)
 717                 printk(KERN_WARNING "lockd: unexpected unlock status: %d\n", status);
 718 die:
 719         nlm_release_host(req->a_host);
 720         nlmclnt_release_lockargs(req);
 721         kfree(req);
 722         return;
 723  retry_rebind:
 724         nlm_rebind_host(req->a_host);
 725  retry_unlock:
 726         rpc_restart_call(task);
 727 }
 728
 729 static const struct rpc_call_ops nlmclnt_unlock_ops = {
 730         .rpc_call_done = nlmclnt_unlock_callback,
 731 };
 732
 733 /*
 734  * Cancel a blocked lock request.
 735  * We always use an async RPC call for this in order not to hang a
 736  * process that has been Ctrl-C'ed.
 737  */
 738 static int nlmclnt_cancel(struct nlm_host *host, int block, struct file_lock *fl)
 739 {
 740         struct nlm_rqst *req;
 741         unsigned long   flags;
 742         sigset_t        oldset;
 743         int             status;
 744
 745         /* Block all signals while setting up call */
 746         spin_lock_irqsave(&current->sighand->siglock, flags);
 747         oldset = current->blocked;
 748         sigfillset(&current->blocked);
 749         recalc_sigpending();
 750         spin_unlock_irqrestore(&current->sighand->siglock, flags);
 751
 752         req = nlmclnt_alloc_call();
 753         if (!req)
 754                 return -ENOMEM;
 755         req->a_host  = host;
 756         req->a_flags = RPC_TASK_ASYNC;
 757
 758         nlmclnt_setlockargs(req, fl);
 759         req->a_args.block = block;
 760
 761         status = nlmclnt_async_call(req, NLMPROC_CANCEL, &nlmclnt_cancel_ops);
 762         if (status < 0) {
 763                 nlmclnt_release_lockargs(req);
 764                 kfree(req);
 765         }
 766
 767         spin_lock_irqsave(&current->sighand->siglock, flags);
 768         current->blocked = oldset;
 769         recalc_sigpending();
 770         spin_unlock_irqrestore(&current->sighand->siglock, flags);
 771
 772         return status;
 773 }
 774
 775 static void nlmclnt_cancel_callback(struct rpc_task *task, void *data)
 776 {
 777         struct nlm_rqst *req = data;
 778
 779         if (RPC_ASSASSINATED(task))
 780                 goto die;
 781
 782         if (task->tk_status < 0) {
 783                 dprintk("lockd: CANCEL call error %d, retrying.\n",
 784                                         task->tk_status);
 785                 goto retry_cancel;
 786         }
 787
 788         dprintk("lockd: cancel status %d (task %d)\n",
 789                         req->a_res.status, task->tk_pid);
 790
 791         switch (req->a_res.status) {
 792         case NLM_LCK_GRANTED:
 793         case NLM_LCK_DENIED_GRACE_PERIOD:
 794                 /* Everything's good */
 795                 break;
 796         case NLM_LCK_DENIED_NOLOCKS:
 797                 dprintk("lockd: CANCEL failed (server has no locks)\n");
 798                 goto retry_cancel;
 799         default:
 800                 printk(KERN_NOTICE "lockd: weird return %d for CANCEL call\n",
 801                         req->a_res.status);
 802         }
 803
 804 die:
 805         nlm_release_host(req->a_host);
 806         nlmclnt_release_lockargs(req);
 807         kfree(req);
 808         return;
 809
 810 retry_cancel:
 811         /* Don't ever retry more than 3 times */
 812         if (req->a_retries++ >= NLMCLNT_MAX_RETRIES)
 813                 goto die;
 814         nlm_rebind_host(req->a_host);
 815         rpc_restart_call(task);
 816         rpc_delay(task, 30 * HZ);
 817 }
 818
 819 static const struct rpc_call_ops nlmclnt_cancel_ops = {
 820         .rpc_call_done = nlmclnt_cancel_callback,
 821 };
 822
 823 /*
 824  * Convert an NLM status code to a generic kernel errno
 825  */
 826 static int
 827 nlm_stat_to_errno(u32 status)
 828 {
 829         switch(status) {
 830         case NLM_LCK_GRANTED:
 831                 return 0;
 832         case NLM_LCK_DENIED:
 833                 return -EAGAIN;
 834         case NLM_LCK_DENIED_NOLOCKS:
 835         case NLM_LCK_DENIED_GRACE_PERIOD:
 836                 return -ENOLCK;
 837         case NLM_LCK_BLOCKED:
 838                 printk(KERN_NOTICE "lockd: unexpected status NLM_BLOCKED\n");
 839                 return -ENOLCK;
 840 #ifdef CONFIG_LOCKD_V4
 841         case NLM_DEADLCK:
 842                 return -EDEADLK;
 843         case NLM_ROFS:
 844                 return -EROFS;
 845         case NLM_STALE_FH:
 846                 return -ESTALE;
 847         case NLM_FBIG:
 848                 return -EOVERFLOW;
 849         case NLM_FAILED:
 850                 return -ENOLCK;
 851 #endif
 852         }
 853         printk(KERN_NOTICE "lockd: unexpected server status %d\n", status);
 854         return -ENOLCK;
 855 }