git.oblomov.eu Git - linux-2.6/blob - fs/lockd/clntproc.c

   1 /*
   2  * linux/fs/lockd/clntproc.c
   3  *
   4  * RPC procedures for the client side NLM implementation
   5  *
   6  * Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de>
   7  */
   8
   9 #include <linux/config.h>
  10 #include <linux/module.h>
  11 #include <linux/types.h>
  12 #include <linux/errno.h>
  13 #include <linux/fs.h>
  14 #include <linux/nfs_fs.h>
  15 #include <linux/utsname.h>
  16 #include <linux/smp_lock.h>
  17 #include <linux/sunrpc/clnt.h>
  18 #include <linux/sunrpc/svc.h>
  19 #include <linux/lockd/lockd.h>
  20 #include <linux/lockd/sm_inter.h>
  21
  22 #define NLMDBG_FACILITY         NLMDBG_CLIENT
  23 #define NLMCLNT_GRACE_WAIT      (5*HZ)
  24 #define NLMCLNT_POLL_TIMEOUT    (30*HZ)
  25
  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 void     nlmclnt_unlock_callback(struct rpc_task *);
  30 static void     nlmclnt_cancel_callback(struct rpc_task *);
  31 static int      nlm_stat_to_errno(u32 stat);
  32 static void     nlmclnt_locks_init_private(struct file_lock *fl, struct nlm_host *host);
  33
  34 /*
  35  * Cookie counter for NLM requests
  36  */
  37 static u32      nlm_cookie = 0x1234;
  38
  39 static inline void nlmclnt_next_cookie(struct nlm_cookie *c)
  40 {
  41         memcpy(c->data, &nlm_cookie, 4);
  42         memset(c->data+4, 0, 4);
  43         c->len=4;
  44         nlm_cookie++;
  45 }
  46
  47 static struct nlm_lockowner *nlm_get_lockowner(struct nlm_lockowner *lockowner)
  48 {
  49         atomic_inc(&lockowner->count);
  50         return lockowner;
  51 }
  52
  53 static void nlm_put_lockowner(struct nlm_lockowner *lockowner)
  54 {
  55         if (!atomic_dec_and_lock(&lockowner->count, &lockowner->host->h_lock))
  56                 return;
  57         list_del(&lockowner->list);
  58         spin_unlock(&lockowner->host->h_lock);
  59         nlm_release_host(lockowner->host);
  60         kfree(lockowner);
  61 }
  62
  63 static inline int nlm_pidbusy(struct nlm_host *host, uint32_t pid)
  64 {
  65         struct nlm_lockowner *lockowner;
  66         list_for_each_entry(lockowner, &host->h_lockowners, list) {
  67                 if (lockowner->pid == pid)
  68                         return -EBUSY;
  69         }
  70         return 0;
  71 }
  72
  73 static inline uint32_t __nlm_alloc_pid(struct nlm_host *host)
  74 {
  75         uint32_t res;
  76         do {
  77                 res = host->h_pidcount++;
  78         } while (nlm_pidbusy(host, res) < 0);
  79         return res;
  80 }
  81
  82 static struct nlm_lockowner *__nlm_find_lockowner(struct nlm_host *host, fl_owner_t owner)
  83 {
  84         struct nlm_lockowner *lockowner;
  85         list_for_each_entry(lockowner, &host->h_lockowners, list) {
  86                 if (lockowner->owner != owner)
  87                         continue;
  88                 return nlm_get_lockowner(lockowner);
  89         }
  90         return NULL;
  91 }
  92
  93 static struct nlm_lockowner *nlm_find_lockowner(struct nlm_host *host, fl_owner_t owner)
  94 {
  95         struct nlm_lockowner *res, *new = NULL;
  96
  97         spin_lock(&host->h_lock);
  98         res = __nlm_find_lockowner(host, owner);
  99         if (res == NULL) {
 100                 spin_unlock(&host->h_lock);
 101                 new = (struct nlm_lockowner *)kmalloc(sizeof(*new), GFP_KERNEL);
 102                 spin_lock(&host->h_lock);
 103                 res = __nlm_find_lockowner(host, owner);
 104                 if (res == NULL && new != NULL) {
 105                         res = new;
 106                         atomic_set(&new->count, 1);
 107                         new->owner = owner;
 108                         new->pid = __nlm_alloc_pid(host);
 109                         new->host = nlm_get_host(host);
 110                         list_add(&new->list, &host->h_lockowners);
 111                         new = NULL;
 112                 }
 113         }
 114         spin_unlock(&host->h_lock);
 115         if (new != NULL)
 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                 current->state = TASK_INTERRUPTIBLE;
 303                 schedule_timeout(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
 405 nlmsvc_async_call(struct nlm_rqst *req, u32 proc, rpc_action callback)
 406 {
 407         struct nlm_host *host = req->a_host;
 408         struct rpc_clnt *clnt;
 409         struct rpc_message msg = {
 410                 .rpc_argp       = &req->a_args,
 411                 .rpc_resp       = &req->a_res,
 412         };
 413         int             status;
 414
 415         dprintk("lockd: call procedure %d on %s (async)\n",
 416                         (int)proc, host->h_name);
 417
 418         /* If we have no RPC client yet, create one. */
 419         if ((clnt = nlm_bind_host(host)) == NULL)
 420                 return -ENOLCK;
 421         msg.rpc_proc = &clnt->cl_procinfo[proc];
 422
 423         /* bootstrap and kick off the async RPC call */
 424         status = rpc_call_async(clnt, &msg, RPC_TASK_ASYNC, callback, req);
 425
 426         return status;
 427 }
 428
 429 static int
 430 nlmclnt_async_call(struct nlm_rqst *req, u32 proc, rpc_action callback)
 431 {
 432         struct nlm_host *host = req->a_host;
 433         struct rpc_clnt *clnt;
 434         struct nlm_args *argp = &req->a_args;
 435         struct nlm_res  *resp = &req->a_res;
 436         struct rpc_message msg = {
 437                 .rpc_argp       = argp,
 438                 .rpc_resp       = resp,
 439         };
 440         int             status;
 441
 442         dprintk("lockd: call procedure %d on %s (async)\n",
 443                         (int)proc, host->h_name);
 444
 445         /* If we have no RPC client yet, create one. */
 446         if ((clnt = nlm_bind_host(host)) == NULL)
 447                 return -ENOLCK;
 448         msg.rpc_proc = &clnt->cl_procinfo[proc];
 449
 450         /* Increment host refcount */
 451         nlm_get_host(host);
 452         /* bootstrap and kick off the async RPC call */
 453         status = rpc_call_async(clnt, &msg, RPC_TASK_ASYNC, callback, req);
 454         if (status < 0)
 455                 nlm_release_host(host);
 456         return status;
 457 }
 458
 459 /*
 460  * TEST for the presence of a conflicting lock
 461  */
 462 static int
 463 nlmclnt_test(struct nlm_rqst *req, struct file_lock *fl)
 464 {
 465         int     status;
 466
 467         status = nlmclnt_call(req, NLMPROC_TEST);
 468         nlmclnt_release_lockargs(req);
 469         if (status < 0)
 470                 return status;
 471
 472         status = req->a_res.status;
 473         if (status == NLM_LCK_GRANTED) {
 474                 fl->fl_type = F_UNLCK;
 475         } if (status == NLM_LCK_DENIED) {
 476                 /*
 477                  * Report the conflicting lock back to the application.
 478                  */
 479                 locks_copy_lock(fl, &req->a_res.lock.fl);
 480                 fl->fl_pid = 0;
 481         } else {
 482                 return nlm_stat_to_errno(req->a_res.status);
 483         }
 484
 485         return 0;
 486 }
 487
 488 static void nlmclnt_locks_copy_lock(struct file_lock *new, struct file_lock *fl)
 489 {
 490         memcpy(&new->fl_u.nfs_fl, &fl->fl_u.nfs_fl, sizeof(new->fl_u.nfs_fl));
 491         nlm_get_lockowner(new->fl_u.nfs_fl.owner);
 492 }
 493
 494 static void nlmclnt_locks_release_private(struct file_lock *fl)
 495 {
 496         nlm_put_lockowner(fl->fl_u.nfs_fl.owner);
 497         fl->fl_ops = NULL;
 498 }
 499
 500 static struct file_lock_operations nlmclnt_lock_ops = {
 501         .fl_copy_lock = nlmclnt_locks_copy_lock,
 502         .fl_release_private = nlmclnt_locks_release_private,
 503 };
 504
 505 static void nlmclnt_locks_init_private(struct file_lock *fl, struct nlm_host *host)
 506 {
 507         BUG_ON(fl->fl_ops != NULL);
 508         fl->fl_u.nfs_fl.state = 0;
 509         fl->fl_u.nfs_fl.flags = 0;
 510         fl->fl_u.nfs_fl.owner = nlm_find_lockowner(host, fl->fl_owner);
 511         fl->fl_ops = &nlmclnt_lock_ops;
 512 }
 513
 514 static void do_vfs_lock(struct file_lock *fl)
 515 {
 516         int res = 0;
 517         switch (fl->fl_flags & (FL_POSIX|FL_FLOCK)) {
 518                 case FL_POSIX:
 519                         res = posix_lock_file_wait(fl->fl_file, fl);
 520                         break;
 521                 case FL_FLOCK:
 522                         res = flock_lock_file_wait(fl->fl_file, fl);
 523                         break;
 524                 default:
 525                         BUG();
 526         }
 527         if (res < 0)
 528                 printk(KERN_WARNING "%s: VFS is out of sync with lock manager!\n",
 529                                 __FUNCTION__);
 530 }
 531
 532 /*
 533  * LOCK: Try to create a lock
 534  *
 535  *                      Programmer Harassment Alert
 536  *
 537  * When given a blocking lock request in a sync RPC call, the HPUX lockd
 538  * will faithfully return LCK_BLOCKED but never cares to notify us when
 539  * the lock could be granted. This way, our local process could hang
 540  * around forever waiting for the callback.
 541  *
 542  *  Solution A: Implement busy-waiting
 543  *  Solution B: Use the async version of the call (NLM_LOCK_{MSG,RES})
 544  *
 545  * For now I am implementing solution A, because I hate the idea of
 546  * re-implementing lockd for a third time in two months. The async
 547  * calls shouldn't be too hard to do, however.
 548  *
 549  * This is one of the lovely things about standards in the NFS area:
 550  * they're so soft and squishy you can't really blame HP for doing this.
 551  */
 552 static int
 553 nlmclnt_lock(struct nlm_rqst *req, struct file_lock *fl)
 554 {
 555         struct nlm_host *host = req->a_host;
 556         struct nlm_res  *resp = &req->a_res;
 557         long timeout;
 558         int status;
 559
 560         if (!host->h_monitored && nsm_monitor(host) < 0) {
 561                 printk(KERN_NOTICE "lockd: failed to monitor %s\n",
 562                                         host->h_name);
 563                 status = -ENOLCK;
 564                 goto out;
 565         }
 566
 567         if (req->a_args.block) {
 568                 status = nlmclnt_prepare_block(req, host, fl);
 569                 if (status < 0)
 570                         goto out;
 571         }
 572         for(;;) {
 573                 status = nlmclnt_call(req, NLMPROC_LOCK);
 574                 if (status < 0)
 575                         goto out_unblock;
 576                 if (resp->status != NLM_LCK_BLOCKED)
 577                         break;
 578                 /* Wait on an NLM blocking lock */
 579                 timeout = nlmclnt_block(req, NLMCLNT_POLL_TIMEOUT);
 580                 /* Did a reclaimer thread notify us of a server reboot? */
 581                 if (resp->status ==  NLM_LCK_DENIED_GRACE_PERIOD)
 582                         continue;
 583                 if (resp->status != NLM_LCK_BLOCKED)
 584                         break;
 585                 if (timeout >= 0)
 586                         continue;
 587                 /* We were interrupted. Send a CANCEL request to the server
 588                  * and exit
 589                  */
 590                 status = (int)timeout;
 591                 goto out_unblock;
 592         }
 593
 594         if (resp->status == NLM_LCK_GRANTED) {
 595                 fl->fl_u.nfs_fl.state = host->h_state;
 596                 fl->fl_u.nfs_fl.flags |= NFS_LCK_GRANTED;
 597                 fl->fl_flags |= FL_SLEEP;
 598                 do_vfs_lock(fl);
 599         }
 600         status = nlm_stat_to_errno(resp->status);
 601 out_unblock:
 602         nlmclnt_finish_block(req);
 603         /* Cancel the blocked request if it is still pending */
 604         if (resp->status == NLM_LCK_BLOCKED)
 605                 nlmclnt_cancel(host, fl);
 606 out:
 607         nlmclnt_release_lockargs(req);
 608         return status;
 609 }
 610
 611 /*
 612  * RECLAIM: Try to reclaim a lock
 613  */
 614 int
 615 nlmclnt_reclaim(struct nlm_host *host, struct file_lock *fl)
 616 {
 617         struct nlm_rqst reqst, *req;
 618         int             status;
 619
 620         req = &reqst;
 621         memset(req, 0, sizeof(*req));
 622         locks_init_lock(&req->a_args.lock.fl);
 623         locks_init_lock(&req->a_res.lock.fl);
 624         req->a_host  = host;
 625         req->a_flags = 0;
 626
 627         /* Set up the argument struct */
 628         nlmclnt_setlockargs(req, fl);
 629         req->a_args.reclaim = 1;
 630
 631         if ((status = nlmclnt_call(req, NLMPROC_LOCK)) >= 0
 632          && req->a_res.status == NLM_LCK_GRANTED)
 633                 return 0;
 634
 635         printk(KERN_WARNING "lockd: failed to reclaim lock for pid %d "
 636                                 "(errno %d, status %d)\n", fl->fl_pid,
 637                                 status, req->a_res.status);
 638
 639         /*
 640          * FIXME: This is a serious failure. We can
 641          *
 642          *  a.  Ignore the problem
 643          *  b.  Send the owning process some signal (Linux doesn't have
 644          *      SIGLOST, though...)
 645          *  c.  Retry the operation
 646          *
 647          * Until someone comes up with a simple implementation
 648          * for b or c, I'll choose option a.
 649          */
 650
 651         return -ENOLCK;
 652 }
 653
 654 /*
 655  * UNLOCK: remove an existing lock
 656  */
 657 static int
 658 nlmclnt_unlock(struct nlm_rqst *req, struct file_lock *fl)
 659 {
 660         struct nlm_res  *resp = &req->a_res;
 661         int             status;
 662
 663         /* Clean the GRANTED flag now so the lock doesn't get
 664          * reclaimed while we're stuck in the unlock call. */
 665         fl->fl_u.nfs_fl.flags &= ~NFS_LCK_GRANTED;
 666
 667         if (req->a_flags & RPC_TASK_ASYNC) {
 668                 status = nlmclnt_async_call(req, NLMPROC_UNLOCK,
 669                                         nlmclnt_unlock_callback);
 670                 /* Hrmf... Do the unlock early since locks_remove_posix()
 671                  * really expects us to free the lock synchronously */
 672                 do_vfs_lock(fl);
 673                 if (status < 0) {
 674                         nlmclnt_release_lockargs(req);
 675                         kfree(req);
 676                 }
 677                 return status;
 678         }
 679
 680         status = nlmclnt_call(req, NLMPROC_UNLOCK);
 681         nlmclnt_release_lockargs(req);
 682         if (status < 0)
 683                 return status;
 684
 685         do_vfs_lock(fl);
 686         if (resp->status == NLM_LCK_GRANTED)
 687                 return 0;
 688
 689         if (resp->status != NLM_LCK_DENIED_NOLOCKS)
 690                 printk("lockd: unexpected unlock status: %d\n", resp->status);
 691
 692         /* What to do now? I'm out of my depth... */
 693
 694         return -ENOLCK;
 695 }
 696
 697 static void
 698 nlmclnt_unlock_callback(struct rpc_task *task)
 699 {
 700         struct nlm_rqst *req = (struct nlm_rqst *) task->tk_calldata;
 701         int             status = req->a_res.status;
 702
 703         if (RPC_ASSASSINATED(task))
 704                 goto die;
 705
 706         if (task->tk_status < 0) {
 707                 dprintk("lockd: unlock failed (err = %d)\n", -task->tk_status);
 708                 goto retry_rebind;
 709         }
 710         if (status == NLM_LCK_DENIED_GRACE_PERIOD) {
 711                 rpc_delay(task, NLMCLNT_GRACE_WAIT);
 712                 goto retry_unlock;
 713         }
 714         if (status != NLM_LCK_GRANTED)
 715                 printk(KERN_WARNING "lockd: unexpected unlock status: %d\n", status);
 716 die:
 717         nlm_release_host(req->a_host);
 718         nlmclnt_release_lockargs(req);
 719         kfree(req);
 720         return;
 721  retry_rebind:
 722         nlm_rebind_host(req->a_host);
 723  retry_unlock:
 724         rpc_restart_call(task);
 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,
 756                                         nlmclnt_cancel_callback);
 757         if (status < 0) {
 758                 nlmclnt_release_lockargs(req);
 759                 kfree(req);
 760         }
 761
 762         spin_lock_irqsave(&current->sighand->siglock, flags);
 763         current->blocked = oldset;
 764         recalc_sigpending();
 765         spin_unlock_irqrestore(&current->sighand->siglock, flags);
 766
 767         return status;
 768 }
 769
 770 static void
 771 nlmclnt_cancel_callback(struct rpc_task *task)
 772 {
 773         struct nlm_rqst *req = (struct nlm_rqst *) task->tk_calldata;
 774
 775         if (RPC_ASSASSINATED(task))
 776                 goto die;
 777
 778         if (task->tk_status < 0) {
 779                 dprintk("lockd: CANCEL call error %d, retrying.\n",
 780                                         task->tk_status);
 781                 goto retry_cancel;
 782         }
 783
 784         dprintk("lockd: cancel status %d (task %d)\n",
 785                         req->a_res.status, task->tk_pid);
 786
 787         switch (req->a_res.status) {
 788         case NLM_LCK_GRANTED:
 789         case NLM_LCK_DENIED_GRACE_PERIOD:
 790                 /* Everything's good */
 791                 break;
 792         case NLM_LCK_DENIED_NOLOCKS:
 793                 dprintk("lockd: CANCEL failed (server has no locks)\n");
 794                 goto retry_cancel;
 795         default:
 796                 printk(KERN_NOTICE "lockd: weird return %d for CANCEL call\n",
 797                         req->a_res.status);
 798         }
 799
 800 die:
 801         nlm_release_host(req->a_host);
 802         nlmclnt_release_lockargs(req);
 803         kfree(req);
 804         return;
 805
 806 retry_cancel:
 807         nlm_rebind_host(req->a_host);
 808         rpc_restart_call(task);
 809         rpc_delay(task, 30 * HZ);
 810 }
 811
 812 /*
 813  * Convert an NLM status code to a generic kernel errno
 814  */
 815 static int
 816 nlm_stat_to_errno(u32 status)
 817 {
 818         switch(status) {
 819         case NLM_LCK_GRANTED:
 820                 return 0;
 821         case NLM_LCK_DENIED:
 822                 return -EAGAIN;
 823         case NLM_LCK_DENIED_NOLOCKS:
 824         case NLM_LCK_DENIED_GRACE_PERIOD:
 825                 return -ENOLCK;
 826         case NLM_LCK_BLOCKED:
 827                 printk(KERN_NOTICE "lockd: unexpected status NLM_BLOCKED\n");
 828                 return -ENOLCK;
 829 #ifdef CONFIG_LOCKD_V4
 830         case NLM_DEADLCK:
 831                 return -EDEADLK;
 832         case NLM_ROFS:
 833                 return -EROFS;
 834         case NLM_STALE_FH:
 835                 return -ESTALE;
 836         case NLM_FBIG:
 837                 return -EOVERFLOW;
 838         case NLM_FAILED:
 839                 return -ENOLCK;
 840 #endif
 841         }
 842         printk(KERN_NOTICE "lockd: unexpected server status %d\n", status);
 843         return -ENOLCK;
 844 }