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   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/types.h>
  24 #include <linux/errno.h>
  25 #include <linux/kernel.h>
  26 #include <linux/sched.h>
  27 #include <linux/smp_lock.h>
  28 #include <linux/sunrpc/clnt.h>
  29 #include <linux/sunrpc/svc.h>
  30 #include <linux/lockd/nlm.h>
  31 #include <linux/lockd/lockd.h>
  32
  33 #define NLMDBG_FACILITY         NLMDBG_SVCLOCK
  34
  35 #ifdef CONFIG_LOCKD_V4
  36 #define nlm_deadlock    nlm4_deadlock
  37 #else
  38 #define nlm_deadlock    nlm_lck_denied
  39 #endif
  40
  41 static void nlmsvc_release_block(struct nlm_block *block);
  42 static void     nlmsvc_insert_block(struct nlm_block *block, unsigned long);
  43 static void     nlmsvc_remove_block(struct nlm_block *block);
  44
  45 static int nlmsvc_setgrantargs(struct nlm_rqst *call, struct nlm_lock *lock);
  46 static void nlmsvc_freegrantargs(struct nlm_rqst *call);
  47 static const struct rpc_call_ops nlmsvc_grant_ops;
  48
  49 /*
  50  * The list of blocked locks to retry
  51  */
  52 static LIST_HEAD(nlm_blocked);
  53
  54 /*
  55  * Insert a blocked lock into the global list
  56  */
  57 static void
  58 nlmsvc_insert_block(struct nlm_block *block, unsigned long when)
  59 {
  60         struct nlm_block *b;
  61         struct list_head *pos;
  62
  63         dprintk("lockd: nlmsvc_insert_block(%p, %ld)\n", block, when);
  64         if (list_empty(&block->b_list)) {
  65                 kref_get(&block->b_count);
  66         } else {
  67                 list_del_init(&block->b_list);
  68         }
  69
  70         pos = &nlm_blocked;
  71         if (when != NLM_NEVER) {
  72                 if ((when += jiffies) == NLM_NEVER)
  73                         when ++;
  74                 list_for_each(pos, &nlm_blocked) {
  75                         b = list_entry(pos, struct nlm_block, b_list);
  76                         if (time_after(b->b_when,when) || b->b_when == NLM_NEVER)
  77                                 break;
  78                 }
  79                 /* On normal exit from the loop, pos == &nlm_blocked,
  80                  * so we will be adding to the end of the list - good
  81                  */
  82         }
  83
  84         list_add_tail(&block->b_list, pos);
  85         block->b_when = when;
  86 }
  87
  88 /*
  89  * Remove a block from the global list
  90  */
  91 static inline void
  92 nlmsvc_remove_block(struct nlm_block *block)
  93 {
  94         if (!list_empty(&block->b_list)) {
  95                 list_del_init(&block->b_list);
  96                 nlmsvc_release_block(block);
  97         }
  98 }
  99
 100 /*
 101  * Find a block for a given lock
 102  */
 103 static struct nlm_block *
 104 nlmsvc_lookup_block(struct nlm_file *file, struct nlm_lock *lock)
 105 {
 106         struct nlm_block        *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         list_for_each_entry(block, &nlm_blocked, b_list) {
 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                         kref_get(&block->b_count);
 122                         return block;
 123                 }
 124         }
 125
 126         return NULL;
 127 }
 128
 129 static inline int nlm_cookie_match(struct nlm_cookie *a, struct nlm_cookie *b)
 130 {
 131         if(a->len != b->len)
 132                 return 0;
 133         if(memcmp(a->data,b->data,a->len))
 134                 return 0;
 135         return 1;
 136 }
 137
 138 /*
 139  * Find a block with a given NLM cookie.
 140  */
 141 static inline struct nlm_block *
 142 nlmsvc_find_block(struct nlm_cookie *cookie,  struct sockaddr_in *sin)
 143 {
 144         struct nlm_block *block;
 145
 146         list_for_each_entry(block, &nlm_blocked, b_list) {
 147                 if (nlm_cookie_match(&block->b_call->a_args.cookie,cookie)
 148                                 && nlm_cmp_addr(sin, &block->b_host->h_addr))
 149                         goto found;
 150         }
 151
 152         return NULL;
 153
 154 found:
 155         kref_get(&block->b_count);
 156         return block;
 157 }
 158
 159 /*
 160  * Create a block and initialize it.
 161  *
 162  * Note: we explicitly set the cookie of the grant reply to that of
 163  * the blocked lock request. The spec explicitly mentions that the client
 164  * should _not_ rely on the callback containing the same cookie as the
 165  * request, but (as I found out later) that's because some implementations
 166  * do just this. Never mind the standards comittees, they support our
 167  * logging industries.
 168  */
 169 static inline struct nlm_block *
 170 nlmsvc_create_block(struct svc_rqst *rqstp, struct nlm_file *file,
 171                                 struct nlm_lock *lock, struct nlm_cookie *cookie)
 172 {
 173         struct nlm_block        *block;
 174         struct nlm_host         *host;
 175         struct nlm_rqst         *call = NULL;
 176
 177         /* Create host handle for callback */
 178         host = nlmsvc_lookup_host(rqstp, lock->caller, lock->len);
 179         if (host == NULL)
 180                 return NULL;
 181
 182         call = nlm_alloc_call(host);
 183         if (call == NULL)
 184                 return NULL;
 185
 186         /* Allocate memory for block, and initialize arguments */
 187         block = kzalloc(sizeof(*block), GFP_KERNEL);
 188         if (block == NULL)
 189                 goto failed;
 190         kref_init(&block->b_count);
 191         INIT_LIST_HEAD(&block->b_list);
 192         INIT_LIST_HEAD(&block->b_flist);
 193
 194         if (!nlmsvc_setgrantargs(call, lock))
 195                 goto failed_free;
 196
 197         /* Set notifier function for VFS, and init args */
 198         call->a_args.lock.fl.fl_flags |= FL_SLEEP;
 199         call->a_args.lock.fl.fl_lmops = &nlmsvc_lock_operations;
 200         call->a_args.cookie = *cookie;  /* see above */
 201
 202         dprintk("lockd: created block %p...\n", block);
 203
 204         /* Create and initialize the block */
 205         block->b_daemon = rqstp->rq_server;
 206         block->b_host   = host;
 207         block->b_file   = file;
 208         file->f_count++;
 209
 210         /* Add to file's list of blocks */
 211         list_add(&block->b_flist, &file->f_blocks);
 212
 213         /* Set up RPC arguments for callback */
 214         block->b_call = call;
 215         call->a_flags   = RPC_TASK_ASYNC;
 216         call->a_block = block;
 217
 218         return block;
 219
 220 failed_free:
 221         kfree(block);
 222 failed:
 223         nlm_release_call(call);
 224         return NULL;
 225 }
 226
 227 /*
 228  * Delete a block. If the lock was cancelled or the grant callback
 229  * failed, unlock is set to 1.
 230  * It is the caller's responsibility to check whether the file
 231  * can be closed hereafter.
 232  */
 233 static int nlmsvc_unlink_block(struct nlm_block *block)
 234 {
 235         int status;
 236         dprintk("lockd: unlinking block %p...\n", block);
 237
 238         /* Remove block from list */
 239         status = posix_unblock_lock(block->b_file->f_file, &block->b_call->a_args.lock.fl);
 240         nlmsvc_remove_block(block);
 241         return status;
 242 }
 243
 244 static void nlmsvc_free_block(struct kref *kref)
 245 {
 246         struct nlm_block *block = container_of(kref, struct nlm_block, b_count);
 247         struct nlm_file         *file = block->b_file;
 248
 249         dprintk("lockd: freeing block %p...\n", block);
 250
 251         /* Remove block from file's list of blocks */
 252         down(&file->f_sema);
 253         list_del_init(&block->b_flist);
 254         up(&file->f_sema);
 255
 256         nlmsvc_freegrantargs(block->b_call);
 257         nlm_release_call(block->b_call);
 258         nlm_release_file(block->b_file);
 259         kfree(block);
 260 }
 261
 262 static void nlmsvc_release_block(struct nlm_block *block)
 263 {
 264         if (block != NULL)
 265                 kref_put(&block->b_count, nlmsvc_free_block);
 266 }
 267
 268 /*
 269  * Loop over all blocks and delete blocks held by
 270  * a matching host.
 271  */
 272 void nlmsvc_traverse_blocks(struct nlm_host *host,
 273                         struct nlm_file *file,
 274                         nlm_host_match_fn_t match)
 275 {
 276         struct nlm_block *block, *next;
 277
 278 restart:
 279         down(&file->f_sema);
 280         list_for_each_entry_safe(block, next, &file->f_blocks, b_flist) {
 281                 if (!match(block->b_host, host))
 282                         continue;
 283                 /* Do not destroy blocks that are not on
 284                  * the global retry list - why? */
 285                 if (list_empty(&block->b_list))
 286                         continue;
 287                 kref_get(&block->b_count);
 288                 up(&file->f_sema);
 289                 nlmsvc_unlink_block(block);
 290                 nlmsvc_release_block(block);
 291                 goto restart;
 292         }
 293         up(&file->f_sema);
 294 }
 295
 296 /*
 297  * Initialize arguments for GRANTED call. The nlm_rqst structure
 298  * has been cleared already.
 299  */
 300 static int nlmsvc_setgrantargs(struct nlm_rqst *call, struct nlm_lock *lock)
 301 {
 302         locks_copy_lock(&call->a_args.lock.fl, &lock->fl);
 303         memcpy(&call->a_args.lock.fh, &lock->fh, sizeof(call->a_args.lock.fh));
 304         call->a_args.lock.caller = utsname()->nodename;
 305         call->a_args.lock.oh.len = lock->oh.len;
 306
 307         /* set default data area */
 308         call->a_args.lock.oh.data = call->a_owner;
 309         call->a_args.lock.svid = lock->fl.fl_pid;
 310
 311         if (lock->oh.len > NLMCLNT_OHSIZE) {
 312                 void *data = kmalloc(lock->oh.len, GFP_KERNEL);
 313                 if (!data)
 314                         return 0;
 315                 call->a_args.lock.oh.data = (u8 *) data;
 316         }
 317
 318         memcpy(call->a_args.lock.oh.data, lock->oh.data, lock->oh.len);
 319         return 1;
 320 }
 321
 322 static void nlmsvc_freegrantargs(struct nlm_rqst *call)
 323 {
 324         if (call->a_args.lock.oh.data != call->a_owner)
 325                 kfree(call->a_args.lock.oh.data);
 326 }
 327
 328 /*
 329  * Attempt to establish a lock, and if it can't be granted, block it
 330  * if required.
 331  */
 332 u32
 333 nlmsvc_lock(struct svc_rqst *rqstp, struct nlm_file *file,
 334                         struct nlm_lock *lock, int wait, struct nlm_cookie *cookie)
 335 {
 336         struct nlm_block        *block, *newblock = NULL;
 337         int                     error;
 338         u32                     ret;
 339
 340         dprintk("lockd: nlmsvc_lock(%s/%ld, ty=%d, pi=%d, %Ld-%Ld, bl=%d)\n",
 341                                 file->f_file->f_dentry->d_inode->i_sb->s_id,
 342                                 file->f_file->f_dentry->d_inode->i_ino,
 343                                 lock->fl.fl_type, lock->fl.fl_pid,
 344                                 (long long)lock->fl.fl_start,
 345                                 (long long)lock->fl.fl_end,
 346                                 wait);
 347
 348
 349         lock->fl.fl_flags &= ~FL_SLEEP;
 350 again:
 351         /* Lock file against concurrent access */
 352         down(&file->f_sema);
 353         /* Get existing block (in case client is busy-waiting) */
 354         block = nlmsvc_lookup_block(file, lock);
 355         if (block == NULL) {
 356                 if (newblock != NULL)
 357                         lock = &newblock->b_call->a_args.lock;
 358         } else
 359                 lock = &block->b_call->a_args.lock;
 360
 361         error = posix_lock_file(file->f_file, &lock->fl);
 362         lock->fl.fl_flags &= ~FL_SLEEP;
 363
 364         dprintk("lockd: posix_lock_file returned %d\n", error);
 365
 366         switch(error) {
 367                 case 0:
 368                         ret = nlm_granted;
 369                         goto out;
 370                 case -EAGAIN:
 371                         break;
 372                 case -EDEADLK:
 373                         ret = nlm_deadlock;
 374                         goto out;
 375                 default:                        /* includes ENOLCK */
 376                         ret = nlm_lck_denied_nolocks;
 377                         goto out;
 378         }
 379
 380         ret = nlm_lck_denied;
 381         if (!wait)
 382                 goto out;
 383
 384         ret = nlm_lck_blocked;
 385         if (block != NULL)
 386                 goto out;
 387
 388         /* If we don't have a block, create and initialize it. Then
 389          * retry because we may have slept in kmalloc. */
 390         /* We have to release f_sema as nlmsvc_create_block may try to
 391          * to claim it while doing host garbage collection */
 392         if (newblock == NULL) {
 393                 up(&file->f_sema);
 394                 dprintk("lockd: blocking on this lock (allocating).\n");
 395                 if (!(newblock = nlmsvc_create_block(rqstp, file, lock, cookie)))
 396                         return nlm_lck_denied_nolocks;
 397                 goto again;
 398         }
 399
 400         /* Append to list of blocked */
 401         nlmsvc_insert_block(newblock, NLM_NEVER);
 402 out:
 403         up(&file->f_sema);
 404         nlmsvc_release_block(newblock);
 405         nlmsvc_release_block(block);
 406         dprintk("lockd: nlmsvc_lock returned %u\n", ret);
 407         return ret;
 408 }
 409
 410 /*
 411  * Test for presence of a conflicting lock.
 412  */
 413 u32
 414 nlmsvc_testlock(struct nlm_file *file, struct nlm_lock *lock,
 415                                        struct nlm_lock *conflock)
 416 {
 417         dprintk("lockd: nlmsvc_testlock(%s/%ld, ty=%d, %Ld-%Ld)\n",
 418                                 file->f_file->f_dentry->d_inode->i_sb->s_id,
 419                                 file->f_file->f_dentry->d_inode->i_ino,
 420                                 lock->fl.fl_type,
 421                                 (long long)lock->fl.fl_start,
 422                                 (long long)lock->fl.fl_end);
 423
 424         if (posix_test_lock(file->f_file, &lock->fl, &conflock->fl)) {
 425                 dprintk("lockd: conflicting lock(ty=%d, %Ld-%Ld)\n",
 426                                 conflock->fl.fl_type,
 427                                 (long long)conflock->fl.fl_start,
 428                                 (long long)conflock->fl.fl_end);
 429                 conflock->caller = "somehost";  /* FIXME */
 430                 conflock->len = strlen(conflock->caller);
 431                 conflock->oh.len = 0;           /* don't return OH info */
 432                 conflock->svid = conflock->fl.fl_pid;
 433                 return nlm_lck_denied;
 434         }
 435
 436         return nlm_granted;
 437 }
 438
 439 /*
 440  * Remove a lock.
 441  * This implies a CANCEL call: We send a GRANT_MSG, the client replies
 442  * with a GRANT_RES call which gets lost, and calls UNLOCK immediately
 443  * afterwards. In this case the block will still be there, and hence
 444  * must be removed.
 445  */
 446 u32
 447 nlmsvc_unlock(struct nlm_file *file, struct nlm_lock *lock)
 448 {
 449         int     error;
 450
 451         dprintk("lockd: nlmsvc_unlock(%s/%ld, pi=%d, %Ld-%Ld)\n",
 452                                 file->f_file->f_dentry->d_inode->i_sb->s_id,
 453                                 file->f_file->f_dentry->d_inode->i_ino,
 454                                 lock->fl.fl_pid,
 455                                 (long long)lock->fl.fl_start,
 456                                 (long long)lock->fl.fl_end);
 457
 458         /* First, cancel any lock that might be there */
 459         nlmsvc_cancel_blocked(file, lock);
 460
 461         lock->fl.fl_type = F_UNLCK;
 462         error = posix_lock_file(file->f_file, &lock->fl);
 463
 464         return (error < 0)? nlm_lck_denied_nolocks : nlm_granted;
 465 }
 466
 467 /*
 468  * Cancel a previously blocked request.
 469  *
 470  * A cancel request always overrides any grant that may currently
 471  * be in progress.
 472  * The calling procedure must check whether the file can be closed.
 473  */
 474 u32
 475 nlmsvc_cancel_blocked(struct nlm_file *file, struct nlm_lock *lock)
 476 {
 477         struct nlm_block        *block;
 478         int status = 0;
 479
 480         dprintk("lockd: nlmsvc_cancel(%s/%ld, pi=%d, %Ld-%Ld)\n",
 481                                 file->f_file->f_dentry->d_inode->i_sb->s_id,
 482                                 file->f_file->f_dentry->d_inode->i_ino,
 483                                 lock->fl.fl_pid,
 484                                 (long long)lock->fl.fl_start,
 485                                 (long long)lock->fl.fl_end);
 486
 487         down(&file->f_sema);
 488         block = nlmsvc_lookup_block(file, lock);
 489         up(&file->f_sema);
 490         if (block != NULL) {
 491                 status = nlmsvc_unlink_block(block);
 492                 nlmsvc_release_block(block);
 493         }
 494         return status ? nlm_lck_denied : nlm_granted;
 495 }
 496
 497 /*
 498  * Unblock a blocked lock request. This is a callback invoked from the
 499  * VFS layer when a lock on which we blocked is removed.
 500  *
 501  * This function doesn't grant the blocked lock instantly, but rather moves
 502  * the block to the head of nlm_blocked where it can be picked up by lockd.
 503  */
 504 static void
 505 nlmsvc_notify_blocked(struct file_lock *fl)
 506 {
 507         struct nlm_block        *block;
 508
 509         dprintk("lockd: VFS unblock notification for block %p\n", fl);
 510         list_for_each_entry(block, &nlm_blocked, b_list) {
 511                 if (nlm_compare_locks(&block->b_call->a_args.lock.fl, fl)) {
 512                         nlmsvc_insert_block(block, 0);
 513                         svc_wake_up(block->b_daemon);
 514                         return;
 515                 }
 516         }
 517
 518         printk(KERN_WARNING "lockd: notification for unknown block!\n");
 519 }
 520
 521 static int nlmsvc_same_owner(struct file_lock *fl1, struct file_lock *fl2)
 522 {
 523         return fl1->fl_owner == fl2->fl_owner && fl1->fl_pid == fl2->fl_pid;
 524 }
 525
 526 struct lock_manager_operations nlmsvc_lock_operations = {
 527         .fl_compare_owner = nlmsvc_same_owner,
 528         .fl_notify = nlmsvc_notify_blocked,
 529 };
 530
 531 /*
 532  * Try to claim a lock that was previously blocked.
 533  *
 534  * Note that we use both the RPC_GRANTED_MSG call _and_ an async
 535  * RPC thread when notifying the client. This seems like overkill...
 536  * Here's why:
 537  *  -   we don't want to use a synchronous RPC thread, otherwise
 538  *      we might find ourselves hanging on a dead portmapper.
 539  *  -   Some lockd implementations (e.g. HP) don't react to
 540  *      RPC_GRANTED calls; they seem to insist on RPC_GRANTED_MSG calls.
 541  */
 542 static void
 543 nlmsvc_grant_blocked(struct nlm_block *block)
 544 {
 545         struct nlm_file         *file = block->b_file;
 546         struct nlm_lock         *lock = &block->b_call->a_args.lock;
 547         int                     error;
 548
 549         dprintk("lockd: grant blocked lock %p\n", block);
 550
 551         /* Unlink block request from list */
 552         nlmsvc_unlink_block(block);
 553
 554         /* If b_granted is true this means we've been here before.
 555          * Just retry the grant callback, possibly refreshing the RPC
 556          * binding */
 557         if (block->b_granted) {
 558                 nlm_rebind_host(block->b_host);
 559                 goto callback;
 560         }
 561
 562         /* Try the lock operation again */
 563         lock->fl.fl_flags |= FL_SLEEP;
 564         error = posix_lock_file(file->f_file, &lock->fl);
 565         lock->fl.fl_flags &= ~FL_SLEEP;
 566
 567         switch (error) {
 568         case 0:
 569                 break;
 570         case -EAGAIN:
 571                 dprintk("lockd: lock still blocked\n");
 572                 nlmsvc_insert_block(block, NLM_NEVER);
 573                 return;
 574         default:
 575                 printk(KERN_WARNING "lockd: unexpected error %d in %s!\n",
 576                                 -error, __FUNCTION__);
 577                 nlmsvc_insert_block(block, 10 * HZ);
 578                 return;
 579         }
 580
 581 callback:
 582         /* Lock was granted by VFS. */
 583         dprintk("lockd: GRANTing blocked lock.\n");
 584         block->b_granted = 1;
 585
 586         /* Schedule next grant callback in 30 seconds */
 587         nlmsvc_insert_block(block, 30 * HZ);
 588
 589         /* Call the client */
 590         kref_get(&block->b_count);
 591         if (nlm_async_call(block->b_call, NLMPROC_GRANTED_MSG,
 592                                                 &nlmsvc_grant_ops) < 0)
 593                 nlmsvc_release_block(block);
 594 }
 595
 596 /*
 597  * This is the callback from the RPC layer when the NLM_GRANTED_MSG
 598  * RPC call has succeeded or timed out.
 599  * Like all RPC callbacks, it is invoked by the rpciod process, so it
 600  * better not sleep. Therefore, we put the blocked lock on the nlm_blocked
 601  * chain once more in order to have it removed by lockd itself (which can
 602  * then sleep on the file semaphore without disrupting e.g. the nfs client).
 603  */
 604 static void nlmsvc_grant_callback(struct rpc_task *task, void *data)
 605 {
 606         struct nlm_rqst         *call = data;
 607         struct nlm_block        *block = call->a_block;
 608         unsigned long           timeout;
 609
 610         dprintk("lockd: GRANT_MSG RPC callback\n");
 611
 612         /* Technically, we should down the file semaphore here. Since we
 613          * move the block towards the head of the queue only, no harm
 614          * can be done, though. */
 615         if (task->tk_status < 0) {
 616                 /* RPC error: Re-insert for retransmission */
 617                 timeout = 10 * HZ;
 618         } else {
 619                 /* Call was successful, now wait for client callback */
 620                 timeout = 60 * HZ;
 621         }
 622         nlmsvc_insert_block(block, timeout);
 623         svc_wake_up(block->b_daemon);
 624 }
 625
 626 static void nlmsvc_grant_release(void *data)
 627 {
 628         struct nlm_rqst         *call = data;
 629
 630         nlmsvc_release_block(call->a_block);
 631 }
 632
 633 static const struct rpc_call_ops nlmsvc_grant_ops = {
 634         .rpc_call_done = nlmsvc_grant_callback,
 635         .rpc_release = nlmsvc_grant_release,
 636 };
 637
 638 /*
 639  * We received a GRANT_RES callback. Try to find the corresponding
 640  * block.
 641  */
 642 void
 643 nlmsvc_grant_reply(struct svc_rqst *rqstp, struct nlm_cookie *cookie, u32 status)
 644 {
 645         struct nlm_block        *block;
 646         struct nlm_file         *file;
 647
 648         dprintk("grant_reply: looking for cookie %x, host (%08x), s=%d \n",
 649                 *(unsigned int *)(cookie->data),
 650                 ntohl(rqstp->rq_addr.sin_addr.s_addr), status);
 651         if (!(block = nlmsvc_find_block(cookie, &rqstp->rq_addr)))
 652                 return;
 653         file = block->b_file;
 654
 655         if (block) {
 656                 if (status == NLM_LCK_DENIED_GRACE_PERIOD) {
 657                         /* Try again in a couple of seconds */
 658                         nlmsvc_insert_block(block, 10 * HZ);
 659                 } else {
 660                         /* Lock is now held by client, or has been rejected.
 661                          * In both cases, the block should be removed. */
 662                         nlmsvc_unlink_block(block);
 663                 }
 664         }
 665         nlmsvc_release_block(block);
 666 }
 667
 668 /*
 669  * Retry all blocked locks that have been notified. This is where lockd
 670  * picks up locks that can be granted, or grant notifications that must
 671  * be retransmitted.
 672  */
 673 unsigned long
 674 nlmsvc_retry_blocked(void)
 675 {
 676         unsigned long   timeout = MAX_SCHEDULE_TIMEOUT;
 677         struct nlm_block *block;
 678
 679         while (!list_empty(&nlm_blocked)) {
 680                 block = list_entry(nlm_blocked.next, struct nlm_block, b_list);
 681
 682                 if (block->b_when == NLM_NEVER)
 683                         break;
 684                 if (time_after(block->b_when,jiffies)) {
 685                         timeout = block->b_when - jiffies;
 686                         break;
 687                 }
 688
 689                 dprintk("nlmsvc_retry_blocked(%p, when=%ld)\n",
 690                         block, block->b_when);
 691                 kref_get(&block->b_count);
 692                 nlmsvc_grant_blocked(block);
 693                 nlmsvc_release_block(block);
 694         }
 695
 696         return timeout;
 697 }