SAFE public projects git trees. - safe/jmp/linux-2.6/blob - fs/lockd/svclock.c

   1 /*
   2  * linux/fs/lockd/svclock.c
   3  *
   4  * Handling of server-side locks, mostly of the blocked variety.
   5  * This is the ugliest part of lockd because we tread on very thin ice.
   6  * GRANT and CANCEL calls may get stuck, meet in mid-flight, etc.
   7  * IMNSHO introducing the grant callback into the NLM protocol was one
   8  * of the worst ideas Sun ever had. Except maybe for the idea of doing
   9  * NFS file locking at all.
  10  *
  11  * I'm trying hard to avoid race conditions by protecting most accesses
  12  * to a file's list of blocked locks through a semaphore. The global
  13  * list of blocked locks is not protected in this fashion however.
  14  * Therefore, some functions (such as the RPC callback for the async grant
  15  * call) move blocked locks towards the head of the list *while some other
  16  * process might be traversing it*. This should not be a problem in
  17  * practice, because this will only cause functions traversing the list
  18  * to visit some blocks twice.
  19  *
  20  * Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de>
  21  */
  22
  23 #include <linux/config.h>
  24 #include <linux/types.h>
  25 #include <linux/errno.h>
  26 #include <linux/kernel.h>
  27 #include <linux/sched.h>
  28 #include <linux/smp_lock.h>
  29 #include <linux/sunrpc/clnt.h>
  30 #include <linux/sunrpc/svc.h>
  31 #include <linux/lockd/nlm.h>
  32 #include <linux/lockd/lockd.h>
  33
  34 #define NLMDBG_FACILITY         NLMDBG_SVCLOCK
  35
  36 #ifdef CONFIG_LOCKD_V4
  37 #define nlm_deadlock    nlm4_deadlock
  38 #else
  39 #define nlm_deadlock    nlm_lck_denied
  40 #endif
  41
  42 static void     nlmsvc_insert_block(struct nlm_block *block, unsigned long);
  43 static int      nlmsvc_remove_block(struct nlm_block *block);
  44
  45 static const struct rpc_call_ops nlmsvc_grant_ops;
  46
  47 /*
  48  * The list of blocked locks to retry
  49  */
  50 static struct nlm_block *       nlm_blocked;
  51
  52 /*
  53  * Insert a blocked lock into the global list
  54  */
  55 static void
  56 nlmsvc_insert_block(struct nlm_block *block, unsigned long when)
  57 {
  58         struct nlm_block **bp, *b;
  59
  60         dprintk("lockd: nlmsvc_insert_block(%p, %ld)\n", block, when);
  61         if (block->b_queued)
  62                 nlmsvc_remove_block(block);
  63         bp = &nlm_blocked;
  64         if (when != NLM_NEVER) {
  65                 if ((when += jiffies) == NLM_NEVER)
  66                         when ++;
  67                 while ((b = *bp) && time_before_eq(b->b_when,when) && b->b_when != NLM_NEVER)
  68                         bp = &b->b_next;
  69         } else
  70                 while ((b = *bp) != 0)
  71                         bp = &b->b_next;
  72
  73         block->b_queued = 1;
  74         block->b_when = when;
  75         block->b_next = b;
  76         *bp = block;
  77 }
  78
  79 /*
  80  * Remove a block from the global list
  81  */
  82 static int
  83 nlmsvc_remove_block(struct nlm_block *block)
  84 {
  85         struct nlm_block **bp, *b;
  86
  87         if (!block->b_queued)
  88                 return 1;
  89         for (bp = &nlm_blocked; (b = *bp) != 0; bp = &b->b_next) {
  90                 if (b == block) {
  91                         *bp = block->b_next;
  92                         block->b_queued = 0;
  93                         return 1;
  94                 }
  95         }
  96
  97         return 0;
  98 }
  99
 100 /*
 101  * Find a block for a given lock and optionally remove it from
 102  * the list.
 103  */
 104 static struct nlm_block *
 105 nlmsvc_lookup_block(struct nlm_file *file, struct nlm_lock *lock, int remove)
 106 {
 107         struct nlm_block        **head, *block;
 108         struct file_lock        *fl;
 109
 110         dprintk("lockd: nlmsvc_lookup_block f=%p pd=%d %Ld-%Ld ty=%d\n",
 111                                 file, lock->fl.fl_pid,
 112                                 (long long)lock->fl.fl_start,
 113                                 (long long)lock->fl.fl_end, lock->fl.fl_type);
 114         for (head = &nlm_blocked; (block = *head) != 0; head = &block->b_next) {
 115                 fl = &block->b_call.a_args.lock.fl;
 116                 dprintk("lockd: check f=%p pd=%d %Ld-%Ld ty=%d cookie=%s\n",
 117                                 block->b_file, fl->fl_pid,
 118                                 (long long)fl->fl_start,
 119                                 (long long)fl->fl_end, fl->fl_type,
 120                                 nlmdbg_cookie2a(&block->b_call.a_args.cookie));
 121                 if (block->b_file == file && nlm_compare_locks(fl, &lock->fl)) {
 122                         if (remove) {
 123                                 *head = block->b_next;
 124                                 block->b_queued = 0;
 125                         }
 126                         return block;
 127                 }
 128         }
 129
 130         return NULL;
 131 }
 132
 133 static inline int nlm_cookie_match(struct nlm_cookie *a, struct nlm_cookie *b)
 134 {
 135         if(a->len != b->len)
 136                 return 0;
 137         if(memcmp(a->data,b->data,a->len))
 138                 return 0;
 139         return 1;
 140 }
 141
 142 /*
 143  * Find a block with a given NLM cookie.
 144  */
 145 static inline struct nlm_block *
 146 nlmsvc_find_block(struct nlm_cookie *cookie,  struct sockaddr_in *sin)
 147 {
 148         struct nlm_block *block;
 149
 150         for (block = nlm_blocked; block; block = block->b_next) {
 151                 dprintk("cookie: head of blocked queue %p, block %p\n",
 152                         nlm_blocked, block);
 153                 if (nlm_cookie_match(&block->b_call.a_args.cookie,cookie)
 154                                 && nlm_cmp_addr(sin, &block->b_host->h_addr))
 155                         break;
 156         }
 157
 158         return block;
 159 }
 160
 161 /*
 162  * Create a block and initialize it.
 163  *
 164  * Note: we explicitly set the cookie of the grant reply to that of
 165  * the blocked lock request. The spec explicitly mentions that the client
 166  * should _not_ rely on the callback containing the same cookie as the
 167  * request, but (as I found out later) that's because some implementations
 168  * do just this. Never mind the standards comittees, they support our
 169  * logging industries.
 170  */
 171 static inline struct nlm_block *
 172 nlmsvc_create_block(struct svc_rqst *rqstp, struct nlm_file *file,
 173                                 struct nlm_lock *lock, struct nlm_cookie *cookie)
 174 {
 175         struct nlm_block        *block;
 176         struct nlm_host         *host;
 177         struct nlm_rqst         *call;
 178
 179         /* Create host handle for callback */
 180         host = nlmclnt_lookup_host(&rqstp->rq_addr,
 181                                 rqstp->rq_prot, rqstp->rq_vers);
 182         if (host == NULL)
 183                 return NULL;
 184
 185         /* Allocate memory for block, and initialize arguments */
 186         if (!(block = (struct nlm_block *) kmalloc(sizeof(*block), GFP_KERNEL)))
 187                 goto failed;
 188         memset(block, 0, sizeof(*block));
 189         locks_init_lock(&block->b_call.a_args.lock.fl);
 190         locks_init_lock(&block->b_call.a_res.lock.fl);
 191
 192         if (!nlmclnt_setgrantargs(&block->b_call, lock))
 193                 goto failed_free;
 194
 195         /* Set notifier function for VFS, and init args */
 196         block->b_call.a_args.lock.fl.fl_lmops = &nlmsvc_lock_operations;
 197         block->b_call.a_args.cookie = *cookie;  /* see above */
 198
 199         dprintk("lockd: created block %p...\n", block);
 200
 201         /* Create and initialize the block */
 202         block->b_daemon = rqstp->rq_server;
 203         block->b_host   = host;
 204         block->b_file   = file;
 205
 206         /* Add to file's list of blocks */
 207         block->b_fnext  = file->f_blocks;
 208         file->f_blocks  = block;
 209
 210         /* Set up RPC arguments for callback */
 211         call = &block->b_call;
 212         call->a_host    = host;
 213         call->a_flags   = RPC_TASK_ASYNC;
 214
 215         return block;
 216
 217 failed_free:
 218         kfree(block);
 219 failed:
 220         nlm_release_host(host);
 221         return NULL;
 222 }
 223
 224 /*
 225  * Delete a block. If the lock was cancelled or the grant callback
 226  * failed, unlock is set to 1.
 227  * It is the caller's responsibility to check whether the file
 228  * can be closed hereafter.
 229  */
 230 static int
 231 nlmsvc_delete_block(struct nlm_block *block, int unlock)
 232 {
 233         struct file_lock        *fl = &block->b_call.a_args.lock.fl;
 234         struct nlm_file         *file = block->b_file;
 235         struct nlm_block        **bp;
 236         int status = 0;
 237
 238         dprintk("lockd: deleting block %p...\n", block);
 239
 240         /* Remove block from list */
 241         nlmsvc_remove_block(block);
 242         if (unlock)
 243                 status = posix_unblock_lock(file->f_file, fl);
 244
 245         /* If the block is in the middle of a GRANT callback,
 246          * don't kill it yet. */
 247         if (block->b_incall) {
 248                 nlmsvc_insert_block(block, NLM_NEVER);
 249                 block->b_done = 1;
 250                 return status;
 251         }
 252
 253         /* Remove block from file's list of blocks */
 254         for (bp = &file->f_blocks; *bp; bp = &(*bp)->b_fnext) {
 255                 if (*bp == block) {
 256                         *bp = block->b_fnext;
 257                         break;
 258                 }
 259         }
 260
 261         if (block->b_host)
 262                 nlm_release_host(block->b_host);
 263         nlmclnt_freegrantargs(&block->b_call);
 264         kfree(block);
 265         return status;
 266 }
 267
 268 /*
 269  * Loop over all blocks and perform the action specified.
 270  * (NLM_ACT_CHECK handled by nlmsvc_inspect_file).
 271  */
 272 int
 273 nlmsvc_traverse_blocks(struct nlm_host *host, struct nlm_file *file, int action)
 274 {
 275         struct nlm_block        *block, *next;
 276         /* XXX: Will everything get cleaned up if we don't unlock here? */
 277
 278         down(&file->f_sema);
 279         for (block = file->f_blocks; block; block = next) {
 280                 next = block->b_fnext;
 281                 if (action == NLM_ACT_MARK)
 282                         block->b_host->h_inuse = 1;
 283                 else if (action == NLM_ACT_UNLOCK) {
 284                         if (host == NULL || host == block->b_host)
 285                                 nlmsvc_delete_block(block, 1);
 286                 }
 287         }
 288         up(&file->f_sema);
 289         return 0;
 290 }
 291
 292 /*
 293  * Attempt to establish a lock, and if it can't be granted, block it
 294  * if required.
 295  */
 296 u32
 297 nlmsvc_lock(struct svc_rqst *rqstp, struct nlm_file *file,
 298                         struct nlm_lock *lock, int wait, struct nlm_cookie *cookie)
 299 {
 300         struct nlm_block        *block;
 301         int                     error;
 302         u32                     ret;
 303
 304         dprintk("lockd: nlmsvc_lock(%s/%ld, ty=%d, pi=%d, %Ld-%Ld, bl=%d)\n",
 305                                 file->f_file->f_dentry->d_inode->i_sb->s_id,
 306                                 file->f_file->f_dentry->d_inode->i_ino,
 307                                 lock->fl.fl_type, lock->fl.fl_pid,
 308                                 (long long)lock->fl.fl_start,
 309                                 (long long)lock->fl.fl_end,
 310                                 wait);
 311
 312
 313         /* Get existing block (in case client is busy-waiting) */
 314         block = nlmsvc_lookup_block(file, lock, 0);
 315
 316         lock->fl.fl_flags |= FL_LOCKD;
 317
 318 again:
 319         /* Lock file against concurrent access */
 320         down(&file->f_sema);
 321
 322         error = posix_lock_file(file->f_file, &lock->fl);
 323
 324         dprintk("lockd: posix_lock_file returned %d\n", error);
 325
 326         if (error != -EAGAIN) {
 327                 if (block)
 328                         nlmsvc_delete_block(block, 0);
 329                 up(&file->f_sema);
 330
 331                 switch(-error) {
 332                 case 0:
 333                         ret = nlm_granted;
 334                         goto out;
 335                 case EDEADLK:
 336                         ret = nlm_deadlock;
 337                         goto out;
 338                 default:                        /* includes ENOLCK */
 339                         ret = nlm_lck_denied_nolocks;
 340                         goto out;
 341                 }
 342         }
 343
 344         if (!wait) {
 345                 ret = nlm_lck_denied;
 346                 goto out_unlock;
 347         }
 348
 349         /* If we don't have a block, create and initialize it. Then
 350          * retry because we may have slept in kmalloc. */
 351         /* We have to release f_sema as nlmsvc_create_block may try to
 352          * to claim it while doing host garbage collection */
 353         if (block == NULL) {
 354                 up(&file->f_sema);
 355                 dprintk("lockd: blocking on this lock (allocating).\n");
 356                 if (!(block = nlmsvc_create_block(rqstp, file, lock, cookie)))
 357                         return nlm_lck_denied_nolocks;
 358                 goto again;
 359         }
 360
 361         /* Append to list of blocked */
 362         nlmsvc_insert_block(block, NLM_NEVER);
 363
 364         ret = nlm_lck_blocked;
 365 out_unlock:
 366         up(&file->f_sema);
 367 out:
 368         dprintk("lockd: nlmsvc_lock returned %u\n", ret);
 369         return ret;
 370 }
 371
 372 /*
 373  * Test for presence of a conflicting lock.
 374  */
 375 u32
 376 nlmsvc_testlock(struct nlm_file *file, struct nlm_lock *lock,
 377                                        struct nlm_lock *conflock)
 378 {
 379         dprintk("lockd: nlmsvc_testlock(%s/%ld, ty=%d, %Ld-%Ld)\n",
 380                                 file->f_file->f_dentry->d_inode->i_sb->s_id,
 381                                 file->f_file->f_dentry->d_inode->i_ino,
 382                                 lock->fl.fl_type,
 383                                 (long long)lock->fl.fl_start,
 384                                 (long long)lock->fl.fl_end);
 385
 386         if (posix_test_lock(file->f_file, &lock->fl, &conflock->fl)) {
 387                 dprintk("lockd: conflicting lock(ty=%d, %Ld-%Ld)\n",
 388                                 conflock->fl.fl_type,
 389                                 (long long)conflock->fl.fl_start,
 390                                 (long long)conflock->fl.fl_end);
 391                 conflock->caller = "somehost";  /* FIXME */
 392                 conflock->oh.len = 0;           /* don't return OH info */
 393                 conflock->svid = conflock->fl.fl_pid;
 394                 return nlm_lck_denied;
 395         }
 396
 397         return nlm_granted;
 398 }
 399
 400 /*
 401  * Remove a lock.
 402  * This implies a CANCEL call: We send a GRANT_MSG, the client replies
 403  * with a GRANT_RES call which gets lost, and calls UNLOCK immediately
 404  * afterwards. In this case the block will still be there, and hence
 405  * must be removed.
 406  */
 407 u32
 408 nlmsvc_unlock(struct nlm_file *file, struct nlm_lock *lock)
 409 {
 410         int     error;
 411
 412         dprintk("lockd: nlmsvc_unlock(%s/%ld, pi=%d, %Ld-%Ld)\n",
 413                                 file->f_file->f_dentry->d_inode->i_sb->s_id,
 414                                 file->f_file->f_dentry->d_inode->i_ino,
 415                                 lock->fl.fl_pid,
 416                                 (long long)lock->fl.fl_start,
 417                                 (long long)lock->fl.fl_end);
 418
 419         /* First, cancel any lock that might be there */
 420         nlmsvc_cancel_blocked(file, lock);
 421
 422         lock->fl.fl_type = F_UNLCK;
 423         error = posix_lock_file(file->f_file, &lock->fl);
 424
 425         return (error < 0)? nlm_lck_denied_nolocks : nlm_granted;
 426 }
 427
 428 /*
 429  * Cancel a previously blocked request.
 430  *
 431  * A cancel request always overrides any grant that may currently
 432  * be in progress.
 433  * The calling procedure must check whether the file can be closed.
 434  */
 435 u32
 436 nlmsvc_cancel_blocked(struct nlm_file *file, struct nlm_lock *lock)
 437 {
 438         struct nlm_block        *block;
 439         int status = 0;
 440
 441         dprintk("lockd: nlmsvc_cancel(%s/%ld, pi=%d, %Ld-%Ld)\n",
 442                                 file->f_file->f_dentry->d_inode->i_sb->s_id,
 443                                 file->f_file->f_dentry->d_inode->i_ino,
 444                                 lock->fl.fl_pid,
 445                                 (long long)lock->fl.fl_start,
 446                                 (long long)lock->fl.fl_end);
 447
 448         down(&file->f_sema);
 449         if ((block = nlmsvc_lookup_block(file, lock, 1)) != NULL)
 450                 status = nlmsvc_delete_block(block, 1);
 451         up(&file->f_sema);
 452         return status ? nlm_lck_denied : nlm_granted;
 453 }
 454
 455 /*
 456  * Unblock a blocked lock request. This is a callback invoked from the
 457  * VFS layer when a lock on which we blocked is removed.
 458  *
 459  * This function doesn't grant the blocked lock instantly, but rather moves
 460  * the block to the head of nlm_blocked where it can be picked up by lockd.
 461  */
 462 static void
 463 nlmsvc_notify_blocked(struct file_lock *fl)
 464 {
 465         struct nlm_block        **bp, *block;
 466
 467         dprintk("lockd: VFS unblock notification for block %p\n", fl);
 468         for (bp = &nlm_blocked; (block = *bp) != 0; bp = &block->b_next) {
 469                 if (nlm_compare_locks(&block->b_call.a_args.lock.fl, fl)) {
 470                         nlmsvc_insert_block(block, 0);
 471                         svc_wake_up(block->b_daemon);
 472                         return;
 473                 }
 474         }
 475
 476         printk(KERN_WARNING "lockd: notification for unknown block!\n");
 477 }
 478
 479 static int nlmsvc_same_owner(struct file_lock *fl1, struct file_lock *fl2)
 480 {
 481         return fl1->fl_owner == fl2->fl_owner && fl1->fl_pid == fl2->fl_pid;
 482 }
 483
 484 struct lock_manager_operations nlmsvc_lock_operations = {
 485         .fl_compare_owner = nlmsvc_same_owner,
 486         .fl_notify = nlmsvc_notify_blocked,
 487 };
 488
 489 /*
 490  * Try to claim a lock that was previously blocked.
 491  *
 492  * Note that we use both the RPC_GRANTED_MSG call _and_ an async
 493  * RPC thread when notifying the client. This seems like overkill...
 494  * Here's why:
 495  *  -   we don't want to use a synchronous RPC thread, otherwise
 496  *      we might find ourselves hanging on a dead portmapper.
 497  *  -   Some lockd implementations (e.g. HP) don't react to
 498  *      RPC_GRANTED calls; they seem to insist on RPC_GRANTED_MSG calls.
 499  */
 500 static void
 501 nlmsvc_grant_blocked(struct nlm_block *block)
 502 {
 503         struct nlm_file         *file = block->b_file;
 504         struct nlm_lock         *lock = &block->b_call.a_args.lock;
 505         int                     error;
 506
 507         dprintk("lockd: grant blocked lock %p\n", block);
 508
 509         /* First thing is lock the file */
 510         down(&file->f_sema);
 511
 512         /* Unlink block request from list */
 513         nlmsvc_remove_block(block);
 514
 515         /* If b_granted is true this means we've been here before.
 516          * Just retry the grant callback, possibly refreshing the RPC
 517          * binding */
 518         if (block->b_granted) {
 519                 nlm_rebind_host(block->b_host);
 520                 goto callback;
 521         }
 522
 523         /* Try the lock operation again */
 524         error = posix_lock_file(file->f_file, &lock->fl);
 525         switch (error) {
 526         case 0:
 527                 break;
 528         case -EAGAIN:
 529                 dprintk("lockd: lock still blocked\n");
 530                 nlmsvc_insert_block(block, NLM_NEVER);
 531                 goto out_unlock;
 532         default:
 533                 printk(KERN_WARNING "lockd: unexpected error %d in %s!\n",
 534                                 -error, __FUNCTION__);
 535                 nlmsvc_insert_block(block, 10 * HZ);
 536                 goto out_unlock;
 537         }
 538
 539 callback:
 540         /* Lock was granted by VFS. */
 541         dprintk("lockd: GRANTing blocked lock.\n");
 542         block->b_granted = 1;
 543         block->b_incall  = 1;
 544
 545         /* Schedule next grant callback in 30 seconds */
 546         nlmsvc_insert_block(block, 30 * HZ);
 547
 548         /* Call the client */
 549         nlm_get_host(block->b_call.a_host);
 550         if (nlmsvc_async_call(&block->b_call, NLMPROC_GRANTED_MSG,
 551                                                 &nlmsvc_grant_ops) < 0)
 552                 nlm_release_host(block->b_call.a_host);
 553 out_unlock:
 554         up(&file->f_sema);
 555 }
 556
 557 /*
 558  * This is the callback from the RPC layer when the NLM_GRANTED_MSG
 559  * RPC call has succeeded or timed out.
 560  * Like all RPC callbacks, it is invoked by the rpciod process, so it
 561  * better not sleep. Therefore, we put the blocked lock on the nlm_blocked
 562  * chain once more in order to have it removed by lockd itself (which can
 563  * then sleep on the file semaphore without disrupting e.g. the nfs client).
 564  */
 565 static void nlmsvc_grant_callback(struct rpc_task *task, void *data)
 566 {
 567         struct nlm_rqst         *call = data;
 568         struct nlm_block        *block;
 569         unsigned long           timeout;
 570         struct sockaddr_in      *peer_addr = RPC_PEERADDR(task->tk_client);
 571
 572         dprintk("lockd: GRANT_MSG RPC callback\n");
 573         dprintk("callback: looking for cookie %s, host (%u.%u.%u.%u)\n",
 574                 nlmdbg_cookie2a(&call->a_args.cookie),
 575                 NIPQUAD(peer_addr->sin_addr.s_addr));
 576         if (!(block = nlmsvc_find_block(&call->a_args.cookie, peer_addr))) {
 577                 dprintk("lockd: no block for cookie %s, host (%u.%u.%u.%u)\n",
 578                         nlmdbg_cookie2a(&call->a_args.cookie),
 579                         NIPQUAD(peer_addr->sin_addr.s_addr));
 580                 return;
 581         }
 582
 583         /* Technically, we should down the file semaphore here. Since we
 584          * move the block towards the head of the queue only, no harm
 585          * can be done, though. */
 586         if (task->tk_status < 0) {
 587                 /* RPC error: Re-insert for retransmission */
 588                 timeout = 10 * HZ;
 589         } else if (block->b_done) {
 590                 /* Block already removed, kill it for real */
 591                 timeout = 0;
 592         } else {
 593                 /* Call was successful, now wait for client callback */
 594                 timeout = 60 * HZ;
 595         }
 596         nlmsvc_insert_block(block, timeout);
 597         svc_wake_up(block->b_daemon);
 598         block->b_incall = 0;
 599
 600         nlm_release_host(call->a_host);
 601 }
 602
 603 static const struct rpc_call_ops nlmsvc_grant_ops = {
 604         .rpc_call_done = nlmsvc_grant_callback,
 605 };
 606
 607 /*
 608  * We received a GRANT_RES callback. Try to find the corresponding
 609  * block.
 610  */
 611 void
 612 nlmsvc_grant_reply(struct svc_rqst *rqstp, struct nlm_cookie *cookie, u32 status)
 613 {
 614         struct nlm_block        *block;
 615         struct nlm_file         *file;
 616
 617         dprintk("grant_reply: looking for cookie %x, host (%08x), s=%d \n",
 618                 *(unsigned int *)(cookie->data),
 619                 ntohl(rqstp->rq_addr.sin_addr.s_addr), status);
 620         if (!(block = nlmsvc_find_block(cookie, &rqstp->rq_addr)))
 621                 return;
 622         file = block->b_file;
 623
 624         file->f_count++;
 625         down(&file->f_sema);
 626         block = nlmsvc_find_block(cookie, &rqstp->rq_addr);
 627         if (block) {
 628                 if (status == NLM_LCK_DENIED_GRACE_PERIOD) {
 629                         /* Try again in a couple of seconds */
 630                         nlmsvc_insert_block(block, 10 * HZ);
 631                         up(&file->f_sema);
 632                 } else {
 633                         /* Lock is now held by client, or has been rejected.
 634                          * In both cases, the block should be removed. */
 635                         up(&file->f_sema);
 636                         if (status == NLM_LCK_GRANTED)
 637                                 nlmsvc_delete_block(block, 0);
 638                         else
 639                                 nlmsvc_delete_block(block, 1);
 640                 }
 641         }
 642         nlm_release_file(file);
 643 }
 644
 645 /*
 646  * Retry all blocked locks that have been notified. This is where lockd
 647  * picks up locks that can be granted, or grant notifications that must
 648  * be retransmitted.
 649  */
 650 unsigned long
 651 nlmsvc_retry_blocked(void)
 652 {
 653         struct nlm_block        *block;
 654
 655         dprintk("nlmsvc_retry_blocked(%p, when=%ld)\n",
 656                         nlm_blocked,
 657                         nlm_blocked? nlm_blocked->b_when : 0);
 658         while ((block = nlm_blocked) != 0) {
 659                 if (block->b_when == NLM_NEVER)
 660                         break;
 661                 if (time_after(block->b_when,jiffies))
 662                         break;
 663                 dprintk("nlmsvc_retry_blocked(%p, when=%ld, done=%d)\n",
 664                         block, block->b_when, block->b_done);
 665                 if (block->b_done)
 666                         nlmsvc_delete_block(block, 0);
 667                 else
 668                         nlmsvc_grant_blocked(block);
 669         }
 670
 671         if ((block = nlm_blocked) && block->b_when != NLM_NEVER)
 672                 return (block->b_when - jiffies);
 673
 674         return MAX_SCHEDULE_TIMEOUT;
 675 }