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