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 static void     nlmsvc_grant_callback(struct rpc_task *task);
  45
  46 /*
  47  * The list of blocked locks to retry
  48  */
  49 static struct nlm_block *       nlm_blocked;
  50
  51 /*
  52  * Insert a blocked lock into the global list
  53  */
  54 static void
  55 nlmsvc_insert_block(struct nlm_block *block, unsigned long when)
  56 {
  57         struct nlm_block **bp, *b;
  58
  59         dprintk("lockd: nlmsvc_insert_block(%p, %ld)\n", block, when);
  60         if (block->b_queued)
  61                 nlmsvc_remove_block(block);
  62         bp = &nlm_blocked;
  63         if (when != NLM_NEVER) {
  64                 if ((when += jiffies) == NLM_NEVER)
  65                         when ++;
  66                 while ((b = *bp) && time_before_eq(b->b_when,when) && b->b_when != NLM_NEVER)
  67                         bp = &b->b_next;
  68         } else
  69                 while ((b = *bp) != 0)
  70                         bp = &b->b_next;
  71
  72         block->b_queued = 1;
  73         block->b_when = when;
  74         block->b_next = b;
  75         *bp = block;
  76 }
  77
  78 /*
  79  * Remove a block from the global list
  80  */
  81 static int
  82 nlmsvc_remove_block(struct nlm_block *block)
  83 {
  84         struct nlm_block **bp, *b;
  85
  86         if (!block->b_queued)
  87                 return 1;
  88         for (bp = &nlm_blocked; (b = *bp) != 0; bp = &b->b_next) {
  89                 if (b == block) {
  90                         *bp = block->b_next;
  91                         block->b_queued = 0;
  92                         return 1;
  93                 }
  94         }
  95
  96         return 0;
  97 }
  98
  99 /*
 100  * Find a block for a given lock and optionally remove it from
 101  * the list.
 102  */
 103 static struct nlm_block *
 104 nlmsvc_lookup_block(struct nlm_file *file, struct nlm_lock *lock, int remove)
 105 {
 106         struct nlm_block        **head, *block;
 107         struct file_lock        *fl;
 108
 109         dprintk("lockd: nlmsvc_lookup_block f=%p pd=%d %Ld-%Ld ty=%d\n",
 110                                 file, lock->fl.fl_pid,
 111                                 (long long)lock->fl.fl_start,
 112                                 (long long)lock->fl.fl_end, lock->fl.fl_type);
 113         for (head = &nlm_blocked; (block = *head) != 0; head = &block->b_next) {
 114                 fl = &block->b_call.a_args.lock.fl;
 115                 dprintk("lockd: check f=%p pd=%d %Ld-%Ld ty=%d cookie=%s\n",
 116                                 block->b_file, fl->fl_pid,
 117                                 (long long)fl->fl_start,
 118                                 (long long)fl->fl_end, fl->fl_type,
 119                                 nlmdbg_cookie2a(&block->b_call.a_args.cookie));
 120                 if (block->b_file == file && nlm_compare_locks(fl, &lock->fl)) {
 121                         if (remove) {
 122                                 *head = block->b_next;
 123                                 block->b_queued = 0;
 124                         }
 125                         return block;
 126                 }
 127         }
 128
 129         return NULL;
 130 }
 131
 132 static inline int nlm_cookie_match(struct nlm_cookie *a, struct nlm_cookie *b)
 133 {
 134         if(a->len != b->len)
 135                 return 0;
 136         if(memcmp(a->data,b->data,a->len))
 137                 return 0;
 138         return 1;
 139 }
 140
 141 /*
 142  * Find a block with a given NLM cookie.
 143  */
 144 static inline struct nlm_block *
 145 nlmsvc_find_block(struct nlm_cookie *cookie,  struct sockaddr_in *sin)
 146 {
 147         struct nlm_block *block;
 148
 149         for (block = nlm_blocked; block; block = block->b_next) {
 150                 dprintk("cookie: head of blocked queue %p, block %p\n",
 151                         nlm_blocked, block);
 152                 if (nlm_cookie_match(&block->b_call.a_args.cookie,cookie)
 153                                 && nlm_cmp_addr(sin, &block->b_host->h_addr))
 154                         break;
 155         }
 156
 157         return block;
 158 }
 159
 160 /*
 161  * Create a block and initialize it.
 162  *
 163  * Note: we explicitly set the cookie of the grant reply to that of
 164  * the blocked lock request. The spec explicitly mentions that the client
 165  * should _not_ rely on the callback containing the same cookie as the
 166  * request, but (as I found out later) that's because some implementations
 167  * do just this. Never mind the standards comittees, they support our
 168  * logging industries.
 169  */
 170 static inline struct nlm_block *
 171 nlmsvc_create_block(struct svc_rqst *rqstp, struct nlm_file *file,
 172                                 struct nlm_lock *lock, struct nlm_cookie *cookie)
 173 {
 174         struct nlm_block        *block;
 175         struct nlm_host         *host;
 176         struct nlm_rqst         *call;
 177
 178         /* Create host handle for callback */
 179         host = nlmclnt_lookup_host(&rqstp->rq_addr,
 180                                 rqstp->rq_prot, rqstp->rq_vers);
 181         if (host == NULL)
 182                 return NULL;
 183
 184         /* Allocate memory for block, and initialize arguments */
 185         if (!(block = (struct nlm_block *) kmalloc(sizeof(*block), GFP_KERNEL)))
 186                 goto failed;
 187         memset(block, 0, sizeof(*block));
 188         locks_init_lock(&block->b_call.a_args.lock.fl);
 189         locks_init_lock(&block->b_call.a_res.lock.fl);
 190
 191         if (!nlmclnt_setgrantargs(&block->b_call, lock))
 192                 goto failed_free;
 193
 194         /* Set notifier function for VFS, and init args */
 195         block->b_call.a_args.lock.fl.fl_lmops = &nlmsvc_lock_operations;
 196         block->b_call.a_args.cookie = *cookie;  /* see above */
 197
 198         dprintk("lockd: created block %p...\n", block);
 199
 200         /* Create and initialize the block */
 201         block->b_daemon = rqstp->rq_server;
 202         block->b_host   = host;
 203         block->b_file   = file;
 204
 205         /* Add to file's list of blocks */
 206         block->b_fnext  = file->f_blocks;
 207         file->f_blocks  = block;
 208
 209         /* Set up RPC arguments for callback */
 210         call = &block->b_call;
 211         call->a_host    = host;
 212         call->a_flags   = RPC_TASK_ASYNC;
 213
 214         return block;
 215
 216 failed_free:
 217         kfree(block);
 218 failed:
 219         nlm_release_host(host);
 220         return NULL;
 221 }
 222
 223 /*
 224  * Delete a block. If the lock was cancelled or the grant callback
 225  * failed, unlock is set to 1.
 226  * It is the caller's responsibility to check whether the file
 227  * can be closed hereafter.
 228  */
 229 static void
 230 nlmsvc_delete_block(struct nlm_block *block, int unlock)
 231 {
 232         struct file_lock        *fl = &block->b_call.a_args.lock.fl;
 233         struct nlm_file         *file = block->b_file;
 234         struct nlm_block        **bp;
 235
 236         dprintk("lockd: deleting block %p...\n", block);
 237
 238         /* Remove block from list */
 239         nlmsvc_remove_block(block);
 240         if (fl->fl_next)
 241                 posix_unblock_lock(file->f_file, fl);
 242         if (unlock) {
 243                 fl->fl_type = F_UNLCK;
 244                 posix_lock_file(file->f_file, fl);
 245                 block->b_granted = 0;
 246         }
 247
 248         /* If the block is in the middle of a GRANT callback,
 249          * don't kill it yet. */
 250         if (block->b_incall) {
 251                 nlmsvc_insert_block(block, NLM_NEVER);
 252                 block->b_done = 1;
 253                 return;
 254         }
 255
 256         /* Remove block from file's list of blocks */
 257         for (bp = &file->f_blocks; *bp; bp = &(*bp)->b_fnext) {
 258                 if (*bp == block) {
 259                         *bp = block->b_fnext;
 260                         break;
 261                 }
 262         }
 263
 264         if (block->b_host)
 265                 nlm_release_host(block->b_host);
 266         nlmclnt_freegrantargs(&block->b_call);
 267         kfree(block);
 268 }
 269
 270 /*
 271  * Loop over all blocks and perform the action specified.
 272  * (NLM_ACT_CHECK handled by nlmsvc_inspect_file).
 273  */
 274 int
 275 nlmsvc_traverse_blocks(struct nlm_host *host, struct nlm_file *file, int action)
 276 {
 277         struct nlm_block        *block, *next;
 278
 279         down(&file->f_sema);
 280         for (block = file->f_blocks; block; block = next) {
 281                 next = block->b_fnext;
 282                 if (action == NLM_ACT_MARK)
 283                         block->b_host->h_inuse = 1;
 284                 else if (action == NLM_ACT_UNLOCK) {
 285                         if (host == NULL || host == block->b_host)
 286                                 nlmsvc_delete_block(block, 1);
 287                 }
 288         }
 289         up(&file->f_sema);
 290         return 0;
 291 }
 292
 293 /*
 294  * Attempt to establish a lock, and if it can't be granted, block it
 295  * if required.
 296  */
 297 u32
 298 nlmsvc_lock(struct svc_rqst *rqstp, struct nlm_file *file,
 299                         struct nlm_lock *lock, int wait, struct nlm_cookie *cookie)
 300 {
 301         struct file_lock        *conflock;
 302         struct nlm_block        *block;
 303         int                     error;
 304
 305         dprintk("lockd: nlmsvc_lock(%s/%ld, ty=%d, pi=%d, %Ld-%Ld, bl=%d)\n",
 306                                 file->f_file->f_dentry->d_inode->i_sb->s_id,
 307                                 file->f_file->f_dentry->d_inode->i_ino,
 308                                 lock->fl.fl_type, lock->fl.fl_pid,
 309                                 (long long)lock->fl.fl_start,
 310                                 (long long)lock->fl.fl_end,
 311                                 wait);
 312
 313
 314         /* Get existing block (in case client is busy-waiting) */
 315         block = nlmsvc_lookup_block(file, lock, 0);
 316
 317         lock->fl.fl_flags |= FL_LOCKD;
 318
 319 again:
 320         /* Lock file against concurrent access */
 321         down(&file->f_sema);
 322
 323         if (!(conflock = posix_test_lock(file->f_file, &lock->fl))) {
 324                 error = posix_lock_file(file->f_file, &lock->fl);
 325
 326                 if (block)
 327                         nlmsvc_delete_block(block, 0);
 328                 up(&file->f_sema);
 329
 330                 dprintk("lockd: posix_lock_file returned %d\n", -error);
 331                 switch(-error) {
 332                 case 0:
 333                         return nlm_granted;
 334                 case EDEADLK:
 335                         return nlm_deadlock;
 336                 case EAGAIN:
 337                         return nlm_lck_denied;
 338                 default:                        /* includes ENOLCK */
 339                         return nlm_lck_denied_nolocks;
 340                 }
 341         }
 342
 343         if (!wait) {
 344                 up(&file->f_sema);
 345                 return nlm_lck_denied;
 346         }
 347
 348         if (posix_locks_deadlock(&lock->fl, conflock)) {
 349                 up(&file->f_sema);
 350                 return nlm_deadlock;
 351         }
 352
 353         /* If we don't have a block, create and initialize it. Then
 354          * retry because we may have slept in kmalloc. */
 355         /* We have to release f_sema as nlmsvc_create_block may try to
 356          * to claim it while doing host garbage collection */
 357         if (block == NULL) {
 358                 up(&file->f_sema);
 359                 dprintk("lockd: blocking on this lock (allocating).\n");
 360                 if (!(block = nlmsvc_create_block(rqstp, file, lock, cookie)))
 361                         return nlm_lck_denied_nolocks;
 362                 goto again;
 363         }
 364
 365         /* Append to list of blocked */
 366         nlmsvc_insert_block(block, NLM_NEVER);
 367
 368         if (list_empty(&block->b_call.a_args.lock.fl.fl_block)) {
 369                 /* Now add block to block list of the conflicting lock
 370                    if we haven't done so. */
 371                 dprintk("lockd: blocking on this lock.\n");
 372                 posix_block_lock(conflock, &block->b_call.a_args.lock.fl);
 373         }
 374
 375         up(&file->f_sema);
 376         return nlm_lck_blocked;
 377 }
 378
 379 /*
 380  * Test for presence of a conflicting lock.
 381  */
 382 u32
 383 nlmsvc_testlock(struct nlm_file *file, struct nlm_lock *lock,
 384                                        struct nlm_lock *conflock)
 385 {
 386         struct file_lock        *fl;
 387
 388         dprintk("lockd: nlmsvc_testlock(%s/%ld, ty=%d, %Ld-%Ld)\n",
 389                                 file->f_file->f_dentry->d_inode->i_sb->s_id,
 390                                 file->f_file->f_dentry->d_inode->i_ino,
 391                                 lock->fl.fl_type,
 392                                 (long long)lock->fl.fl_start,
 393                                 (long long)lock->fl.fl_end);
 394
 395         if ((fl = posix_test_lock(file->f_file, &lock->fl)) != NULL) {
 396                 dprintk("lockd: conflicting lock(ty=%d, %Ld-%Ld)\n",
 397                                 fl->fl_type, (long long)fl->fl_start,
 398                                 (long long)fl->fl_end);
 399                 conflock->caller = "somehost";  /* FIXME */
 400                 conflock->oh.len = 0;           /* don't return OH info */
 401                 conflock->fl = *fl;
 402                 return nlm_lck_denied;
 403         }
 404
 405         return nlm_granted;
 406 }
 407
 408 /*
 409  * Remove a lock.
 410  * This implies a CANCEL call: We send a GRANT_MSG, the client replies
 411  * with a GRANT_RES call which gets lost, and calls UNLOCK immediately
 412  * afterwards. In this case the block will still be there, and hence
 413  * must be removed.
 414  */
 415 u32
 416 nlmsvc_unlock(struct nlm_file *file, struct nlm_lock *lock)
 417 {
 418         int     error;
 419
 420         dprintk("lockd: nlmsvc_unlock(%s/%ld, pi=%d, %Ld-%Ld)\n",
 421                                 file->f_file->f_dentry->d_inode->i_sb->s_id,
 422                                 file->f_file->f_dentry->d_inode->i_ino,
 423                                 lock->fl.fl_pid,
 424                                 (long long)lock->fl.fl_start,
 425                                 (long long)lock->fl.fl_end);
 426
 427         /* First, cancel any lock that might be there */
 428         nlmsvc_cancel_blocked(file, lock);
 429
 430         lock->fl.fl_type = F_UNLCK;
 431         error = posix_lock_file(file->f_file, &lock->fl);
 432
 433         return (error < 0)? nlm_lck_denied_nolocks : nlm_granted;
 434 }
 435
 436 /*
 437  * Cancel a previously blocked request.
 438  *
 439  * A cancel request always overrides any grant that may currently
 440  * be in progress.
 441  * The calling procedure must check whether the file can be closed.
 442  */
 443 u32
 444 nlmsvc_cancel_blocked(struct nlm_file *file, struct nlm_lock *lock)
 445 {
 446         struct nlm_block        *block;
 447
 448         dprintk("lockd: nlmsvc_cancel(%s/%ld, pi=%d, %Ld-%Ld)\n",
 449                                 file->f_file->f_dentry->d_inode->i_sb->s_id,
 450                                 file->f_file->f_dentry->d_inode->i_ino,
 451                                 lock->fl.fl_pid,
 452                                 (long long)lock->fl.fl_start,
 453                                 (long long)lock->fl.fl_end);
 454
 455         down(&file->f_sema);
 456         if ((block = nlmsvc_lookup_block(file, lock, 1)) != NULL)
 457                 nlmsvc_delete_block(block, 1);
 458         up(&file->f_sema);
 459         return nlm_granted;
 460 }
 461
 462 /*
 463  * Unblock a blocked lock request. This is a callback invoked from the
 464  * VFS layer when a lock on which we blocked is removed.
 465  *
 466  * This function doesn't grant the blocked lock instantly, but rather moves
 467  * the block to the head of nlm_blocked where it can be picked up by lockd.
 468  */
 469 static void
 470 nlmsvc_notify_blocked(struct file_lock *fl)
 471 {
 472         struct nlm_block        **bp, *block;
 473
 474         dprintk("lockd: VFS unblock notification for block %p\n", fl);
 475         for (bp = &nlm_blocked; (block = *bp) != 0; bp = &block->b_next) {
 476                 if (nlm_compare_locks(&block->b_call.a_args.lock.fl, fl)) {
 477                         nlmsvc_insert_block(block, 0);
 478                         svc_wake_up(block->b_daemon);
 479                         return;
 480                 }
 481         }
 482
 483         printk(KERN_WARNING "lockd: notification for unknown block!\n");
 484 }
 485
 486 static int nlmsvc_same_owner(struct file_lock *fl1, struct file_lock *fl2)
 487 {
 488         return fl1->fl_owner == fl2->fl_owner && fl1->fl_pid == fl2->fl_pid;
 489 }
 490
 491 struct lock_manager_operations nlmsvc_lock_operations = {
 492         .fl_compare_owner = nlmsvc_same_owner,
 493         .fl_notify = nlmsvc_notify_blocked,
 494 };
 495
 496 /*
 497  * Try to claim a lock that was previously blocked.
 498  *
 499  * Note that we use both the RPC_GRANTED_MSG call _and_ an async
 500  * RPC thread when notifying the client. This seems like overkill...
 501  * Here's why:
 502  *  -   we don't want to use a synchronous RPC thread, otherwise
 503  *      we might find ourselves hanging on a dead portmapper.
 504  *  -   Some lockd implementations (e.g. HP) don't react to
 505  *      RPC_GRANTED calls; they seem to insist on RPC_GRANTED_MSG calls.
 506  */
 507 static void
 508 nlmsvc_grant_blocked(struct nlm_block *block)
 509 {
 510         struct nlm_file         *file = block->b_file;
 511         struct nlm_lock         *lock = &block->b_call.a_args.lock;
 512         struct file_lock        *conflock;
 513         int                     error;
 514
 515         dprintk("lockd: grant blocked lock %p\n", block);
 516
 517         /* First thing is lock the file */
 518         down(&file->f_sema);
 519
 520         /* Unlink block request from list */
 521         nlmsvc_remove_block(block);
 522
 523         /* If b_granted is true this means we've been here before.
 524          * Just retry the grant callback, possibly refreshing the RPC
 525          * binding */
 526         if (block->b_granted) {
 527                 nlm_rebind_host(block->b_host);
 528                 goto callback;
 529         }
 530
 531         /* Try the lock operation again */
 532         if ((conflock = posix_test_lock(file->f_file, &lock->fl)) != NULL) {
 533                 /* Bummer, we blocked again */
 534                 dprintk("lockd: lock still blocked\n");
 535                 nlmsvc_insert_block(block, NLM_NEVER);
 536                 posix_block_lock(conflock, &lock->fl);
 537                 up(&file->f_sema);
 538                 return;
 539         }
 540
 541         /* Alright, no conflicting lock. Now lock it for real. If the
 542          * following yields an error, this is most probably due to low
 543          * memory. Retry the lock in a few seconds.
 544          */
 545         if ((error = posix_lock_file(file->f_file, &lock->fl)) < 0) {
 546                 printk(KERN_WARNING "lockd: unexpected error %d in %s!\n",
 547                                 -error, __FUNCTION__);
 548                 nlmsvc_insert_block(block, 10 * HZ);
 549                 up(&file->f_sema);
 550                 return;
 551         }
 552
 553 callback:
 554         /* Lock was granted by VFS. */
 555         dprintk("lockd: GRANTing blocked lock.\n");
 556         block->b_granted = 1;
 557         block->b_incall  = 1;
 558
 559         /* Schedule next grant callback in 30 seconds */
 560         nlmsvc_insert_block(block, 30 * HZ);
 561
 562         /* Call the client */
 563         nlm_get_host(block->b_call.a_host);
 564         if (nlmsvc_async_call(&block->b_call, NLMPROC_GRANTED_MSG,
 565                                                 nlmsvc_grant_callback) < 0)
 566                 nlm_release_host(block->b_call.a_host);
 567         up(&file->f_sema);
 568 }
 569
 570 /*
 571  * This is the callback from the RPC layer when the NLM_GRANTED_MSG
 572  * RPC call has succeeded or timed out.
 573  * Like all RPC callbacks, it is invoked by the rpciod process, so it
 574  * better not sleep. Therefore, we put the blocked lock on the nlm_blocked
 575  * chain once more in order to have it removed by lockd itself (which can
 576  * then sleep on the file semaphore without disrupting e.g. the nfs client).
 577  */
 578 static void
 579 nlmsvc_grant_callback(struct rpc_task *task)
 580 {
 581         struct nlm_rqst         *call = (struct nlm_rqst *) task->tk_calldata;
 582         struct nlm_block        *block;
 583         unsigned long           timeout;
 584         struct sockaddr_in      *peer_addr = RPC_PEERADDR(task->tk_client);
 585
 586         dprintk("lockd: GRANT_MSG RPC callback\n");
 587         dprintk("callback: looking for cookie %s, host (%u.%u.%u.%u)\n",
 588                 nlmdbg_cookie2a(&call->a_args.cookie),
 589                 NIPQUAD(peer_addr->sin_addr.s_addr));
 590         if (!(block = nlmsvc_find_block(&call->a_args.cookie, peer_addr))) {
 591                 dprintk("lockd: no block for cookie %s, host (%u.%u.%u.%u)\n",
 592                         nlmdbg_cookie2a(&call->a_args.cookie),
 593                         NIPQUAD(peer_addr->sin_addr.s_addr));
 594                 return;
 595         }
 596
 597         /* Technically, we should down the file semaphore here. Since we
 598          * move the block towards the head of the queue only, no harm
 599          * can be done, though. */
 600         if (task->tk_status < 0) {
 601                 /* RPC error: Re-insert for retransmission */
 602                 timeout = 10 * HZ;
 603         } else if (block->b_done) {
 604                 /* Block already removed, kill it for real */
 605                 timeout = 0;
 606         } else {
 607                 /* Call was successful, now wait for client callback */
 608                 timeout = 60 * HZ;
 609         }
 610         nlmsvc_insert_block(block, timeout);
 611         svc_wake_up(block->b_daemon);
 612         block->b_incall = 0;
 613
 614         nlm_release_host(call->a_host);
 615 }
 616
 617 /*
 618  * We received a GRANT_RES callback. Try to find the corresponding
 619  * block.
 620  */
 621 void
 622 nlmsvc_grant_reply(struct svc_rqst *rqstp, struct nlm_cookie *cookie, u32 status)
 623 {
 624         struct nlm_block        *block;
 625         struct nlm_file         *file;
 626
 627         dprintk("grant_reply: looking for cookie %x, host (%08x), s=%d \n",
 628                 *(unsigned int *)(cookie->data),
 629                 ntohl(rqstp->rq_addr.sin_addr.s_addr), status);
 630         if (!(block = nlmsvc_find_block(cookie, &rqstp->rq_addr)))
 631                 return;
 632         file = block->b_file;
 633
 634         file->f_count++;
 635         down(&file->f_sema);
 636         if ((block = nlmsvc_find_block(cookie,&rqstp->rq_addr)) != NULL) {
 637                 if (status == NLM_LCK_DENIED_GRACE_PERIOD) {
 638                         /* Try again in a couple of seconds */
 639                         nlmsvc_insert_block(block, 10 * HZ);
 640                         block = NULL;
 641                 } else {
 642                         /* Lock is now held by client, or has been rejected.
 643                          * In both cases, the block should be removed. */
 644                         up(&file->f_sema);
 645                         if (status == NLM_LCK_GRANTED)
 646                                 nlmsvc_delete_block(block, 0);
 647                         else
 648                                 nlmsvc_delete_block(block, 1);
 649                 }
 650         }
 651         if (!block)
 652                 up(&file->f_sema);
 653         nlm_release_file(file);
 654 }
 655
 656 /*
 657  * Retry all blocked locks that have been notified. This is where lockd
 658  * picks up locks that can be granted, or grant notifications that must
 659  * be retransmitted.
 660  */
 661 unsigned long
 662 nlmsvc_retry_blocked(void)
 663 {
 664         struct nlm_block        *block;
 665
 666         dprintk("nlmsvc_retry_blocked(%p, when=%ld)\n",
 667                         nlm_blocked,
 668                         nlm_blocked? nlm_blocked->b_when : 0);
 669         while ((block = nlm_blocked) != 0) {
 670                 if (block->b_when == NLM_NEVER)
 671                         break;
 672                 if (time_after(block->b_when,jiffies))
 673                         break;
 674                 dprintk("nlmsvc_retry_blocked(%p, when=%ld, done=%d)\n",
 675                         block, block->b_when, block->b_done);
 676                 if (block->b_done)
 677                         nlmsvc_delete_block(block, 0);
 678                 else
 679                         nlmsvc_grant_blocked(block);
 680         }
 681
 682         if ((block = nlm_blocked) && block->b_when != NLM_NEVER)
 683                 return (block->b_when - jiffies);
 684
 685         return MAX_SCHEDULE_TIMEOUT;
 686 }