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_flags |= FL_SLEEP;
 197         block->b_call.a_args.lock.fl.fl_lmops = &nlmsvc_lock_operations;
 198         block->b_call.a_args.cookie = *cookie;  /* see above */
 199
 200         dprintk("lockd: created block %p...\n", block);
 201
 202         /* Create and initialize the block */
 203         block->b_daemon = rqstp->rq_server;
 204         block->b_host   = host;
 205         block->b_file   = file;
 206
 207         /* Add to file's list of blocks */
 208         block->b_fnext  = file->f_blocks;
 209         file->f_blocks  = block;
 210
 211         /* Set up RPC arguments for callback */
 212         call = &block->b_call;
 213         call->a_host    = host;
 214         call->a_flags   = RPC_TASK_ASYNC;
 215
 216         return block;
 217
 218 failed_free:
 219         kfree(block);
 220 failed:
 221         nlm_release_host(host);
 222         return NULL;
 223 }
 224
 225 /*
 226  * Delete a block. If the lock was cancelled or the grant callback
 227  * failed, unlock is set to 1.
 228  * It is the caller's responsibility to check whether the file
 229  * can be closed hereafter.
 230  */
 231 static int
 232 nlmsvc_delete_block(struct nlm_block *block)
 233 {
 234         struct file_lock        *fl = &block->b_call.a_args.lock.fl;
 235         struct nlm_file         *file = block->b_file;
 236         struct nlm_block        **bp;
 237         int status;
 238
 239         dprintk("lockd: deleting block %p...\n", block);
 240
 241         /* Remove block from list */
 242         nlmsvc_remove_block(block);
 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);
 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, *newblock = NULL;
 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         lock->fl.fl_flags &= ~FL_SLEEP;
 314 again:
 315         /* Lock file against concurrent access */
 316         down(&file->f_sema);
 317         /* Get existing block (in case client is busy-waiting) */
 318         block = nlmsvc_lookup_block(file, lock, 0);
 319         if (block == NULL) {
 320                 if (newblock != NULL)
 321                         lock = &newblock->b_call.a_args.lock.fl;
 322         } else
 323                 lock = &block->b_call.a_args.lock.fl;
 324
 325         error = posix_lock_file(file->f_file, &lock->fl);
 326         lock->fl.fl_flags &= ~FL_SLEEP;
 327
 328         dprintk("lockd: posix_lock_file returned %d\n", error);
 329
 330         switch(error) {
 331                 case 0:
 332                         ret = nlm_granted;
 333                         goto out;
 334                 case -EAGAIN:
 335                         break;
 336                 case -EDEADLK:
 337                         ret = nlm_deadlock;
 338                         goto out;
 339                 default:                        /* includes ENOLCK */
 340                         ret = nlm_lck_denied_nolocks;
 341                         goto out;
 342         }
 343
 344         ret = nlm_lck_denied;
 345         if (!wait)
 346                 goto out;
 347
 348         ret = nlm_lck_blocked;
 349         if (block != NULL)
 350                 goto out;
 351
 352         /* If we don't have a block, create and initialize it. Then
 353          * retry because we may have slept in kmalloc. */
 354         /* We have to release f_sema as nlmsvc_create_block may try to
 355          * to claim it while doing host garbage collection */
 356         if (newblock == NULL) {
 357                 up(&file->f_sema);
 358                 dprintk("lockd: blocking on this lock (allocating).\n");
 359                 if (!(newblock = nlmsvc_create_block(rqstp, file, lock, cookie)))
 360                         return nlm_lck_denied_nolocks;
 361                 goto again;
 362         }
 363
 364         /* Append to list of blocked */
 365         nlmsvc_insert_block(newblock, NLM_NEVER);
 366         newblock = NULL;
 367
 368 out:
 369         up(&file->f_sema);
 370         if (newblock != NULL)
 371                 nlmsvc_delete_block(newblock);
 372         dprintk("lockd: nlmsvc_lock returned %u\n", ret);
 373         return ret;
 374 }
 375
 376 /*
 377  * Test for presence of a conflicting lock.
 378  */
 379 u32
 380 nlmsvc_testlock(struct nlm_file *file, struct nlm_lock *lock,
 381                                        struct nlm_lock *conflock)
 382 {
 383         dprintk("lockd: nlmsvc_testlock(%s/%ld, ty=%d, %Ld-%Ld)\n",
 384                                 file->f_file->f_dentry->d_inode->i_sb->s_id,
 385                                 file->f_file->f_dentry->d_inode->i_ino,
 386                                 lock->fl.fl_type,
 387                                 (long long)lock->fl.fl_start,
 388                                 (long long)lock->fl.fl_end);
 389
 390         if (posix_test_lock(file->f_file, &lock->fl, &conflock->fl)) {
 391                 dprintk("lockd: conflicting lock(ty=%d, %Ld-%Ld)\n",
 392                                 conflock->fl.fl_type,
 393                                 (long long)conflock->fl.fl_start,
 394                                 (long long)conflock->fl.fl_end);
 395                 conflock->caller = "somehost";  /* FIXME */
 396                 conflock->oh.len = 0;           /* don't return OH info */
 397                 conflock->svid = conflock->fl.fl_pid;
 398                 return nlm_lck_denied;
 399         }
 400
 401         return nlm_granted;
 402 }
 403
 404 /*
 405  * Remove a lock.
 406  * This implies a CANCEL call: We send a GRANT_MSG, the client replies
 407  * with a GRANT_RES call which gets lost, and calls UNLOCK immediately
 408  * afterwards. In this case the block will still be there, and hence
 409  * must be removed.
 410  */
 411 u32
 412 nlmsvc_unlock(struct nlm_file *file, struct nlm_lock *lock)
 413 {
 414         int     error;
 415
 416         dprintk("lockd: nlmsvc_unlock(%s/%ld, pi=%d, %Ld-%Ld)\n",
 417                                 file->f_file->f_dentry->d_inode->i_sb->s_id,
 418                                 file->f_file->f_dentry->d_inode->i_ino,
 419                                 lock->fl.fl_pid,
 420                                 (long long)lock->fl.fl_start,
 421                                 (long long)lock->fl.fl_end);
 422
 423         /* First, cancel any lock that might be there */
 424         nlmsvc_cancel_blocked(file, lock);
 425
 426         lock->fl.fl_type = F_UNLCK;
 427         error = posix_lock_file(file->f_file, &lock->fl);
 428
 429         return (error < 0)? nlm_lck_denied_nolocks : nlm_granted;
 430 }
 431
 432 /*
 433  * Cancel a previously blocked request.
 434  *
 435  * A cancel request always overrides any grant that may currently
 436  * be in progress.
 437  * The calling procedure must check whether the file can be closed.
 438  */
 439 u32
 440 nlmsvc_cancel_blocked(struct nlm_file *file, struct nlm_lock *lock)
 441 {
 442         struct nlm_block        *block;
 443         int status = 0;
 444
 445         dprintk("lockd: nlmsvc_cancel(%s/%ld, pi=%d, %Ld-%Ld)\n",
 446                                 file->f_file->f_dentry->d_inode->i_sb->s_id,
 447                                 file->f_file->f_dentry->d_inode->i_ino,
 448                                 lock->fl.fl_pid,
 449                                 (long long)lock->fl.fl_start,
 450                                 (long long)lock->fl.fl_end);
 451
 452         down(&file->f_sema);
 453         if ((block = nlmsvc_lookup_block(file, lock, 1)) != NULL)
 454                 status = nlmsvc_delete_block(block);
 455         up(&file->f_sema);
 456         return status ? nlm_lck_denied : nlm_granted;
 457 }
 458
 459 /*
 460  * Unblock a blocked lock request. This is a callback invoked from the
 461  * VFS layer when a lock on which we blocked is removed.
 462  *
 463  * This function doesn't grant the blocked lock instantly, but rather moves
 464  * the block to the head of nlm_blocked where it can be picked up by lockd.
 465  */
 466 static void
 467 nlmsvc_notify_blocked(struct file_lock *fl)
 468 {
 469         struct nlm_block        **bp, *block;
 470
 471         dprintk("lockd: VFS unblock notification for block %p\n", fl);
 472         for (bp = &nlm_blocked; (block = *bp) != 0; bp = &block->b_next) {
 473                 if (nlm_compare_locks(&block->b_call.a_args.lock.fl, fl)) {
 474                         nlmsvc_insert_block(block, 0);
 475                         svc_wake_up(block->b_daemon);
 476                         return;
 477                 }
 478         }
 479
 480         printk(KERN_WARNING "lockd: notification for unknown block!\n");
 481 }
 482
 483 static int nlmsvc_same_owner(struct file_lock *fl1, struct file_lock *fl2)
 484 {
 485         return fl1->fl_owner == fl2->fl_owner && fl1->fl_pid == fl2->fl_pid;
 486 }
 487
 488 struct lock_manager_operations nlmsvc_lock_operations = {
 489         .fl_compare_owner = nlmsvc_same_owner,
 490         .fl_notify = nlmsvc_notify_blocked,
 491 };
 492
 493 /*
 494  * Try to claim a lock that was previously blocked.
 495  *
 496  * Note that we use both the RPC_GRANTED_MSG call _and_ an async
 497  * RPC thread when notifying the client. This seems like overkill...
 498  * Here's why:
 499  *  -   we don't want to use a synchronous RPC thread, otherwise
 500  *      we might find ourselves hanging on a dead portmapper.
 501  *  -   Some lockd implementations (e.g. HP) don't react to
 502  *      RPC_GRANTED calls; they seem to insist on RPC_GRANTED_MSG calls.
 503  */
 504 static void
 505 nlmsvc_grant_blocked(struct nlm_block *block)
 506 {
 507         struct nlm_file         *file = block->b_file;
 508         struct nlm_lock         *lock = &block->b_call.a_args.lock;
 509         int                     error;
 510
 511         dprintk("lockd: grant blocked lock %p\n", block);
 512
 513         /* First thing is lock the file */
 514         down(&file->f_sema);
 515
 516         /* Unlink block request from list */
 517         nlmsvc_remove_block(block);
 518
 519         /* If b_granted is true this means we've been here before.
 520          * Just retry the grant callback, possibly refreshing the RPC
 521          * binding */
 522         if (block->b_granted) {
 523                 nlm_rebind_host(block->b_host);
 524                 goto callback;
 525         }
 526
 527         /* Try the lock operation again */
 528         posix_unblock_lock(file->f_file, &lock->fl);
 529         lock->fl.fl_flags |= FL_SLEEP;
 530         error = posix_lock_file(file->f_file, &lock->fl);
 531         lock->fl.fl_flags &= ~FL_SLEEP;
 532
 533         switch (error) {
 534         case 0:
 535                 break;
 536         case -EAGAIN:
 537                 dprintk("lockd: lock still blocked\n");
 538                 nlmsvc_insert_block(block, NLM_NEVER);
 539                 goto out_unlock;
 540         default:
 541                 printk(KERN_WARNING "lockd: unexpected error %d in %s!\n",
 542                                 -error, __FUNCTION__);
 543                 nlmsvc_insert_block(block, 10 * HZ);
 544                 goto out_unlock;
 545         }
 546
 547 callback:
 548         /* Lock was granted by VFS. */
 549         dprintk("lockd: GRANTing blocked lock.\n");
 550         block->b_granted = 1;
 551         block->b_incall  = 1;
 552
 553         /* Schedule next grant callback in 30 seconds */
 554         nlmsvc_insert_block(block, 30 * HZ);
 555
 556         /* Call the client */
 557         nlm_get_host(block->b_call.a_host);
 558         if (nlmsvc_async_call(&block->b_call, NLMPROC_GRANTED_MSG,
 559                                                 &nlmsvc_grant_ops) < 0)
 560                 nlm_release_host(block->b_call.a_host);
 561 out_unlock:
 562         up(&file->f_sema);
 563 }
 564
 565 /*
 566  * This is the callback from the RPC layer when the NLM_GRANTED_MSG
 567  * RPC call has succeeded or timed out.
 568  * Like all RPC callbacks, it is invoked by the rpciod process, so it
 569  * better not sleep. Therefore, we put the blocked lock on the nlm_blocked
 570  * chain once more in order to have it removed by lockd itself (which can
 571  * then sleep on the file semaphore without disrupting e.g. the nfs client).
 572  */
 573 static void nlmsvc_grant_callback(struct rpc_task *task, void *data)
 574 {
 575         struct nlm_rqst         *call = data;
 576         struct nlm_block        *block;
 577         unsigned long           timeout;
 578         struct sockaddr_in      *peer_addr = RPC_PEERADDR(task->tk_client);
 579
 580         dprintk("lockd: GRANT_MSG RPC callback\n");
 581         dprintk("callback: looking for cookie %s, host (%u.%u.%u.%u)\n",
 582                 nlmdbg_cookie2a(&call->a_args.cookie),
 583                 NIPQUAD(peer_addr->sin_addr.s_addr));
 584         if (!(block = nlmsvc_find_block(&call->a_args.cookie, peer_addr))) {
 585                 dprintk("lockd: no block for cookie %s, host (%u.%u.%u.%u)\n",
 586                         nlmdbg_cookie2a(&call->a_args.cookie),
 587                         NIPQUAD(peer_addr->sin_addr.s_addr));
 588                 return;
 589         }
 590
 591         /* Technically, we should down the file semaphore here. Since we
 592          * move the block towards the head of the queue only, no harm
 593          * can be done, though. */
 594         if (task->tk_status < 0) {
 595                 /* RPC error: Re-insert for retransmission */
 596                 timeout = 10 * HZ;
 597         } else if (block->b_done) {
 598                 /* Block already removed, kill it for real */
 599                 timeout = 0;
 600         } else {
 601                 /* Call was successful, now wait for client callback */
 602                 timeout = 60 * HZ;
 603         }
 604         nlmsvc_insert_block(block, timeout);
 605         svc_wake_up(block->b_daemon);
 606         block->b_incall = 0;
 607
 608         nlm_release_host(call->a_host);
 609 }
 610
 611 static const struct rpc_call_ops nlmsvc_grant_ops = {
 612         .rpc_call_done = nlmsvc_grant_callback,
 613 };
 614
 615 /*
 616  * We received a GRANT_RES callback. Try to find the corresponding
 617  * block.
 618  */
 619 void
 620 nlmsvc_grant_reply(struct svc_rqst *rqstp, struct nlm_cookie *cookie, u32 status)
 621 {
 622         struct nlm_block        *block;
 623         struct nlm_file         *file;
 624
 625         dprintk("grant_reply: looking for cookie %x, host (%08x), s=%d \n",
 626                 *(unsigned int *)(cookie->data),
 627                 ntohl(rqstp->rq_addr.sin_addr.s_addr), status);
 628         if (!(block = nlmsvc_find_block(cookie, &rqstp->rq_addr)))
 629                 return;
 630         file = block->b_file;
 631
 632         file->f_count++;
 633         down(&file->f_sema);
 634         block = nlmsvc_find_block(cookie, &rqstp->rq_addr);
 635         if (block) {
 636                 if (status == NLM_LCK_DENIED_GRACE_PERIOD) {
 637                         /* Try again in a couple of seconds */
 638                         nlmsvc_insert_block(block, 10 * HZ);
 639                         up(&file->f_sema);
 640                 } else {
 641                         /* Lock is now held by client, or has been rejected.
 642                          * In both cases, the block should be removed. */
 643                         nlmsvc_delete_block(block);
 644                         up(&file->f_sema);
 645                 }
 646         }
 647         nlm_release_file(file);
 648 }
 649
 650 /*
 651  * Retry all blocked locks that have been notified. This is where lockd
 652  * picks up locks that can be granted, or grant notifications that must
 653  * be retransmitted.
 654  */
 655 unsigned long
 656 nlmsvc_retry_blocked(void)
 657 {
 658         struct nlm_block        *block;
 659
 660         dprintk("nlmsvc_retry_blocked(%p, when=%ld)\n",
 661                         nlm_blocked,
 662                         nlm_blocked? nlm_blocked->b_when : 0);
 663         while ((block = nlm_blocked) != 0) {
 664                 if (block->b_when == NLM_NEVER)
 665                         break;
 666                 if (time_after(block->b_when,jiffies))
 667                         break;
 668                 dprintk("nlmsvc_retry_blocked(%p, when=%ld, done=%d)\n",
 669                         block, block->b_when, block->b_done);
 670                 if (block->b_done)
 671                         nlmsvc_delete_block(block);
 672                 else
 673                         nlmsvc_grant_blocked(block);
 674         }
 675
 676         if ((block = nlm_blocked) && block->b_when != NLM_NEVER)
 677                 return (block->b_when - jiffies);
 678
 679         return MAX_SCHEDULE_TIMEOUT;
 680 }