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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/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_release_block(struct nlm_block *block);
  43 static void     nlmsvc_insert_block(struct nlm_block *block, unsigned long);
  44 static int      nlmsvc_remove_block(struct nlm_block *block);
  45
  46 static int nlmsvc_setgrantargs(struct nlm_rqst *call, struct nlm_lock *lock);
  47 static void nlmsvc_freegrantargs(struct nlm_rqst *call);
  48 static const struct rpc_call_ops nlmsvc_grant_ops;
  49
  50 /*
  51  * The list of blocked locks to retry
  52  */
  53 static struct nlm_block *       nlm_blocked;
  54
  55 /*
  56  * Insert a blocked lock into the global list
  57  */
  58 static void
  59 nlmsvc_insert_block(struct nlm_block *block, unsigned long when)
  60 {
  61         struct nlm_block **bp, *b;
  62
  63         dprintk("lockd: nlmsvc_insert_block(%p, %ld)\n", block, when);
  64         kref_get(&block->b_count);
  65         if (block->b_queued)
  66                 nlmsvc_remove_block(block);
  67         bp = &nlm_blocked;
  68         if (when != NLM_NEVER) {
  69                 if ((when += jiffies) == NLM_NEVER)
  70                         when ++;
  71                 while ((b = *bp) && time_before_eq(b->b_when,when) && b->b_when != NLM_NEVER)
  72                         bp = &b->b_next;
  73         } else
  74                 while ((b = *bp) != 0)
  75                         bp = &b->b_next;
  76
  77         block->b_queued = 1;
  78         block->b_when = when;
  79         block->b_next = b;
  80         *bp = block;
  81 }
  82
  83 /*
  84  * Remove a block from the global list
  85  */
  86 static int
  87 nlmsvc_remove_block(struct nlm_block *block)
  88 {
  89         struct nlm_block **bp, *b;
  90
  91         if (!block->b_queued)
  92                 return 1;
  93         for (bp = &nlm_blocked; (b = *bp) != 0; bp = &b->b_next) {
  94                 if (b == block) {
  95                         *bp = block->b_next;
  96                         block->b_queued = 0;
  97                         nlmsvc_release_block(block);
  98                         return 1;
  99                 }
 100         }
 101
 102         return 0;
 103 }
 104
 105 /*
 106  * Find a block for a given lock and optionally remove it from
 107  * the list.
 108  */
 109 static struct nlm_block *
 110 nlmsvc_lookup_block(struct nlm_file *file, struct nlm_lock *lock, int remove)
 111 {
 112         struct nlm_block        **head, *block;
 113         struct file_lock        *fl;
 114
 115         dprintk("lockd: nlmsvc_lookup_block f=%p pd=%d %Ld-%Ld ty=%d\n",
 116                                 file, lock->fl.fl_pid,
 117                                 (long long)lock->fl.fl_start,
 118                                 (long long)lock->fl.fl_end, lock->fl.fl_type);
 119         for (head = &nlm_blocked; (block = *head) != 0; head = &block->b_next) {
 120                 fl = &block->b_call->a_args.lock.fl;
 121                 dprintk("lockd: check f=%p pd=%d %Ld-%Ld ty=%d cookie=%s\n",
 122                                 block->b_file, fl->fl_pid,
 123                                 (long long)fl->fl_start,
 124                                 (long long)fl->fl_end, fl->fl_type,
 125                                 nlmdbg_cookie2a(&block->b_call->a_args.cookie));
 126                 if (block->b_file == file && nlm_compare_locks(fl, &lock->fl)) {
 127                         if (remove) {
 128                                 *head = block->b_next;
 129                                 block->b_queued = 0;
 130                         }
 131                         kref_get(&block->b_count);
 132                         return block;
 133                 }
 134         }
 135
 136         return NULL;
 137 }
 138
 139 static inline int nlm_cookie_match(struct nlm_cookie *a, struct nlm_cookie *b)
 140 {
 141         if(a->len != b->len)
 142                 return 0;
 143         if(memcmp(a->data,b->data,a->len))
 144                 return 0;
 145         return 1;
 146 }
 147
 148 /*
 149  * Find a block with a given NLM cookie.
 150  */
 151 static inline struct nlm_block *
 152 nlmsvc_find_block(struct nlm_cookie *cookie,  struct sockaddr_in *sin)
 153 {
 154         struct nlm_block *block;
 155
 156         for (block = nlm_blocked; block; block = block->b_next) {
 157                 dprintk("cookie: head of blocked queue %p, block %p\n",
 158                         nlm_blocked, block);
 159                 if (nlm_cookie_match(&block->b_call->a_args.cookie,cookie)
 160                                 && nlm_cmp_addr(sin, &block->b_host->h_addr))
 161                         break;
 162         }
 163
 164         if (block != NULL)
 165                 kref_get(&block->b_count);
 166         return block;
 167 }
 168
 169 /*
 170  * Create a block and initialize it.
 171  *
 172  * Note: we explicitly set the cookie of the grant reply to that of
 173  * the blocked lock request. The spec explicitly mentions that the client
 174  * should _not_ rely on the callback containing the same cookie as the
 175  * request, but (as I found out later) that's because some implementations
 176  * do just this. Never mind the standards comittees, they support our
 177  * logging industries.
 178  */
 179 static inline struct nlm_block *
 180 nlmsvc_create_block(struct svc_rqst *rqstp, struct nlm_file *file,
 181                                 struct nlm_lock *lock, struct nlm_cookie *cookie)
 182 {
 183         struct nlm_block        *block;
 184         struct nlm_host         *host;
 185         struct nlm_rqst         *call = NULL;
 186
 187         /* Create host handle for callback */
 188         host = nlmsvc_lookup_host(rqstp);
 189         if (host == NULL)
 190                 return NULL;
 191
 192         call = nlm_alloc_call(host);
 193         if (call == NULL)
 194                 return NULL;
 195
 196         /* Allocate memory for block, and initialize arguments */
 197         block = kzalloc(sizeof(*block), GFP_KERNEL);
 198         if (block == NULL)
 199                 goto failed;
 200         kref_init(&block->b_count);
 201
 202         if (!nlmsvc_setgrantargs(call, lock))
 203                 goto failed_free;
 204
 205         /* Set notifier function for VFS, and init args */
 206         call->a_args.lock.fl.fl_flags |= FL_SLEEP;
 207         call->a_args.lock.fl.fl_lmops = &nlmsvc_lock_operations;
 208         call->a_args.cookie = *cookie;  /* see above */
 209
 210         dprintk("lockd: created block %p...\n", block);
 211
 212         /* Create and initialize the block */
 213         block->b_daemon = rqstp->rq_server;
 214         block->b_host   = host;
 215         block->b_file   = file;
 216
 217         /* Add to file's list of blocks */
 218         block->b_fnext  = file->f_blocks;
 219         file->f_blocks  = block;
 220
 221         /* Set up RPC arguments for callback */
 222         block->b_call = call;
 223         call->a_flags   = RPC_TASK_ASYNC;
 224         call->a_block = block;
 225
 226         return block;
 227
 228 failed_free:
 229         kfree(block);
 230 failed:
 231         nlm_release_call(call);
 232         return NULL;
 233 }
 234
 235 /*
 236  * Delete a block. If the lock was cancelled or the grant callback
 237  * failed, unlock is set to 1.
 238  * It is the caller's responsibility to check whether the file
 239  * can be closed hereafter.
 240  */
 241 static int nlmsvc_unlink_block(struct nlm_block *block)
 242 {
 243         int status;
 244         dprintk("lockd: unlinking block %p...\n", block);
 245
 246         /* Remove block from list */
 247         status = posix_unblock_lock(block->b_file->f_file, &block->b_call->a_args.lock.fl);
 248         nlmsvc_remove_block(block);
 249         return status;
 250 }
 251
 252 static void nlmsvc_free_block(struct kref *kref)
 253 {
 254         struct nlm_block *block = container_of(kref, struct nlm_block, b_count);
 255         struct nlm_file         *file = block->b_file;
 256         struct nlm_block        **bp;
 257
 258         dprintk("lockd: freeing block %p...\n", block);
 259
 260         /* Remove block from file's list of blocks */
 261         for (bp = &file->f_blocks; *bp; bp = &(*bp)->b_fnext) {
 262                 if (*bp == block) {
 263                         *bp = block->b_fnext;
 264                         break;
 265                 }
 266         }
 267
 268         nlmsvc_freegrantargs(block->b_call);
 269         nlm_release_call(block->b_call);
 270         kfree(block);
 271 }
 272
 273 static void nlmsvc_release_block(struct nlm_block *block)
 274 {
 275         if (block != NULL)
 276                 kref_put(&block->b_count, nlmsvc_free_block);
 277 }
 278
 279 /*
 280  * Loop over all blocks and perform the action specified.
 281  * (NLM_ACT_CHECK handled by nlmsvc_inspect_file).
 282  */
 283 int
 284 nlmsvc_traverse_blocks(struct nlm_host *host, struct nlm_file *file, int action)
 285 {
 286         struct nlm_block        *block, *next;
 287         /* XXX: Will everything get cleaned up if we don't unlock here? */
 288
 289         down(&file->f_sema);
 290         for (block = file->f_blocks; block; block = next) {
 291                 next = block->b_fnext;
 292                 if (action == NLM_ACT_MARK)
 293                         block->b_host->h_inuse = 1;
 294                 else if (action == NLM_ACT_UNLOCK) {
 295                         if (host == NULL || host == block->b_host)
 296                                 nlmsvc_unlink_block(block);
 297                 }
 298         }
 299         up(&file->f_sema);
 300         return 0;
 301 }
 302
 303 /*
 304  * Initialize arguments for GRANTED call. The nlm_rqst structure
 305  * has been cleared already.
 306  */
 307 static int nlmsvc_setgrantargs(struct nlm_rqst *call, struct nlm_lock *lock)
 308 {
 309         locks_copy_lock(&call->a_args.lock.fl, &lock->fl);
 310         memcpy(&call->a_args.lock.fh, &lock->fh, sizeof(call->a_args.lock.fh));
 311         call->a_args.lock.caller = system_utsname.nodename;
 312         call->a_args.lock.oh.len = lock->oh.len;
 313
 314         /* set default data area */
 315         call->a_args.lock.oh.data = call->a_owner;
 316         call->a_args.lock.svid = lock->fl.fl_pid;
 317
 318         if (lock->oh.len > NLMCLNT_OHSIZE) {
 319                 void *data = kmalloc(lock->oh.len, GFP_KERNEL);
 320                 if (!data)
 321                         return 0;
 322                 call->a_args.lock.oh.data = (u8 *) data;
 323         }
 324
 325         memcpy(call->a_args.lock.oh.data, lock->oh.data, lock->oh.len);
 326         return 1;
 327 }
 328
 329 static void nlmsvc_freegrantargs(struct nlm_rqst *call)
 330 {
 331         if (call->a_args.lock.oh.data != call->a_owner)
 332                 kfree(call->a_args.lock.oh.data);
 333 }
 334
 335 /*
 336  * Attempt to establish a lock, and if it can't be granted, block it
 337  * if required.
 338  */
 339 u32
 340 nlmsvc_lock(struct svc_rqst *rqstp, struct nlm_file *file,
 341                         struct nlm_lock *lock, int wait, struct nlm_cookie *cookie)
 342 {
 343         struct nlm_block        *block, *newblock = NULL;
 344         int                     error;
 345         u32                     ret;
 346
 347         dprintk("lockd: nlmsvc_lock(%s/%ld, ty=%d, pi=%d, %Ld-%Ld, bl=%d)\n",
 348                                 file->f_file->f_dentry->d_inode->i_sb->s_id,
 349                                 file->f_file->f_dentry->d_inode->i_ino,
 350                                 lock->fl.fl_type, lock->fl.fl_pid,
 351                                 (long long)lock->fl.fl_start,
 352                                 (long long)lock->fl.fl_end,
 353                                 wait);
 354
 355
 356         lock->fl.fl_flags &= ~FL_SLEEP;
 357 again:
 358         /* Lock file against concurrent access */
 359         down(&file->f_sema);
 360         /* Get existing block (in case client is busy-waiting) */
 361         block = nlmsvc_lookup_block(file, lock, 0);
 362         if (block == NULL) {
 363                 if (newblock != NULL)
 364                         lock = &newblock->b_call->a_args.lock;
 365         } else
 366                 lock = &block->b_call->a_args.lock;
 367
 368         error = posix_lock_file(file->f_file, &lock->fl);
 369         lock->fl.fl_flags &= ~FL_SLEEP;
 370
 371         dprintk("lockd: posix_lock_file returned %d\n", error);
 372
 373         switch(error) {
 374                 case 0:
 375                         ret = nlm_granted;
 376                         goto out;
 377                 case -EAGAIN:
 378                         break;
 379                 case -EDEADLK:
 380                         ret = nlm_deadlock;
 381                         goto out;
 382                 default:                        /* includes ENOLCK */
 383                         ret = nlm_lck_denied_nolocks;
 384                         goto out;
 385         }
 386
 387         ret = nlm_lck_denied;
 388         if (!wait)
 389                 goto out;
 390
 391         ret = nlm_lck_blocked;
 392         if (block != NULL)
 393                 goto out;
 394
 395         /* If we don't have a block, create and initialize it. Then
 396          * retry because we may have slept in kmalloc. */
 397         /* We have to release f_sema as nlmsvc_create_block may try to
 398          * to claim it while doing host garbage collection */
 399         if (newblock == NULL) {
 400                 up(&file->f_sema);
 401                 dprintk("lockd: blocking on this lock (allocating).\n");
 402                 if (!(newblock = nlmsvc_create_block(rqstp, file, lock, cookie)))
 403                         return nlm_lck_denied_nolocks;
 404                 goto again;
 405         }
 406
 407         /* Append to list of blocked */
 408         nlmsvc_insert_block(newblock, NLM_NEVER);
 409 out:
 410         up(&file->f_sema);
 411         nlmsvc_release_block(newblock);
 412         nlmsvc_release_block(block);
 413         dprintk("lockd: nlmsvc_lock returned %u\n", ret);
 414         return ret;
 415 }
 416
 417 /*
 418  * Test for presence of a conflicting lock.
 419  */
 420 u32
 421 nlmsvc_testlock(struct nlm_file *file, struct nlm_lock *lock,
 422                                        struct nlm_lock *conflock)
 423 {
 424         dprintk("lockd: nlmsvc_testlock(%s/%ld, ty=%d, %Ld-%Ld)\n",
 425                                 file->f_file->f_dentry->d_inode->i_sb->s_id,
 426                                 file->f_file->f_dentry->d_inode->i_ino,
 427                                 lock->fl.fl_type,
 428                                 (long long)lock->fl.fl_start,
 429                                 (long long)lock->fl.fl_end);
 430
 431         if (posix_test_lock(file->f_file, &lock->fl, &conflock->fl)) {
 432                 dprintk("lockd: conflicting lock(ty=%d, %Ld-%Ld)\n",
 433                                 conflock->fl.fl_type,
 434                                 (long long)conflock->fl.fl_start,
 435                                 (long long)conflock->fl.fl_end);
 436                 conflock->caller = "somehost";  /* FIXME */
 437                 conflock->oh.len = 0;           /* don't return OH info */
 438                 conflock->svid = conflock->fl.fl_pid;
 439                 return nlm_lck_denied;
 440         }
 441
 442         return nlm_granted;
 443 }
 444
 445 /*
 446  * Remove a lock.
 447  * This implies a CANCEL call: We send a GRANT_MSG, the client replies
 448  * with a GRANT_RES call which gets lost, and calls UNLOCK immediately
 449  * afterwards. In this case the block will still be there, and hence
 450  * must be removed.
 451  */
 452 u32
 453 nlmsvc_unlock(struct nlm_file *file, struct nlm_lock *lock)
 454 {
 455         int     error;
 456
 457         dprintk("lockd: nlmsvc_unlock(%s/%ld, pi=%d, %Ld-%Ld)\n",
 458                                 file->f_file->f_dentry->d_inode->i_sb->s_id,
 459                                 file->f_file->f_dentry->d_inode->i_ino,
 460                                 lock->fl.fl_pid,
 461                                 (long long)lock->fl.fl_start,
 462                                 (long long)lock->fl.fl_end);
 463
 464         /* First, cancel any lock that might be there */
 465         nlmsvc_cancel_blocked(file, lock);
 466
 467         lock->fl.fl_type = F_UNLCK;
 468         error = posix_lock_file(file->f_file, &lock->fl);
 469
 470         return (error < 0)? nlm_lck_denied_nolocks : nlm_granted;
 471 }
 472
 473 /*
 474  * Cancel a previously blocked request.
 475  *
 476  * A cancel request always overrides any grant that may currently
 477  * be in progress.
 478  * The calling procedure must check whether the file can be closed.
 479  */
 480 u32
 481 nlmsvc_cancel_blocked(struct nlm_file *file, struct nlm_lock *lock)
 482 {
 483         struct nlm_block        *block;
 484         int status = 0;
 485
 486         dprintk("lockd: nlmsvc_cancel(%s/%ld, pi=%d, %Ld-%Ld)\n",
 487                                 file->f_file->f_dentry->d_inode->i_sb->s_id,
 488                                 file->f_file->f_dentry->d_inode->i_ino,
 489                                 lock->fl.fl_pid,
 490                                 (long long)lock->fl.fl_start,
 491                                 (long long)lock->fl.fl_end);
 492
 493         down(&file->f_sema);
 494         if ((block = nlmsvc_lookup_block(file, lock, 1)) != NULL) {
 495                 status = nlmsvc_unlink_block(block);
 496                 nlmsvc_release_block(block);
 497         }
 498         up(&file->f_sema);
 499         return status ? nlm_lck_denied : nlm_granted;
 500 }
 501
 502 /*
 503  * Unblock a blocked lock request. This is a callback invoked from the
 504  * VFS layer when a lock on which we blocked is removed.
 505  *
 506  * This function doesn't grant the blocked lock instantly, but rather moves
 507  * the block to the head of nlm_blocked where it can be picked up by lockd.
 508  */
 509 static void
 510 nlmsvc_notify_blocked(struct file_lock *fl)
 511 {
 512         struct nlm_block        **bp, *block;
 513
 514         dprintk("lockd: VFS unblock notification for block %p\n", fl);
 515         for (bp = &nlm_blocked; (block = *bp) != 0; bp = &block->b_next) {
 516                 if (nlm_compare_locks(&block->b_call->a_args.lock.fl, fl)) {
 517                         nlmsvc_insert_block(block, 0);
 518                         svc_wake_up(block->b_daemon);
 519                         return;
 520                 }
 521         }
 522
 523         printk(KERN_WARNING "lockd: notification for unknown block!\n");
 524 }
 525
 526 static int nlmsvc_same_owner(struct file_lock *fl1, struct file_lock *fl2)
 527 {
 528         return fl1->fl_owner == fl2->fl_owner && fl1->fl_pid == fl2->fl_pid;
 529 }
 530
 531 struct lock_manager_operations nlmsvc_lock_operations = {
 532         .fl_compare_owner = nlmsvc_same_owner,
 533         .fl_notify = nlmsvc_notify_blocked,
 534 };
 535
 536 /*
 537  * Try to claim a lock that was previously blocked.
 538  *
 539  * Note that we use both the RPC_GRANTED_MSG call _and_ an async
 540  * RPC thread when notifying the client. This seems like overkill...
 541  * Here's why:
 542  *  -   we don't want to use a synchronous RPC thread, otherwise
 543  *      we might find ourselves hanging on a dead portmapper.
 544  *  -   Some lockd implementations (e.g. HP) don't react to
 545  *      RPC_GRANTED calls; they seem to insist on RPC_GRANTED_MSG calls.
 546  */
 547 static void
 548 nlmsvc_grant_blocked(struct nlm_block *block)
 549 {
 550         struct nlm_file         *file = block->b_file;
 551         struct nlm_lock         *lock = &block->b_call->a_args.lock;
 552         int                     error;
 553
 554         dprintk("lockd: grant blocked lock %p\n", block);
 555
 556         /* First thing is lock the file */
 557         down(&file->f_sema);
 558
 559         /* Unlink block request from list */
 560         nlmsvc_unlink_block(block);
 561
 562         /* If b_granted is true this means we've been here before.
 563          * Just retry the grant callback, possibly refreshing the RPC
 564          * binding */
 565         if (block->b_granted) {
 566                 nlm_rebind_host(block->b_host);
 567                 goto callback;
 568         }
 569
 570         /* Try the lock operation again */
 571         lock->fl.fl_flags |= FL_SLEEP;
 572         error = posix_lock_file(file->f_file, &lock->fl);
 573         lock->fl.fl_flags &= ~FL_SLEEP;
 574
 575         switch (error) {
 576         case 0:
 577                 break;
 578         case -EAGAIN:
 579                 dprintk("lockd: lock still blocked\n");
 580                 nlmsvc_insert_block(block, NLM_NEVER);
 581                 goto out_unlock;
 582         default:
 583                 printk(KERN_WARNING "lockd: unexpected error %d in %s!\n",
 584                                 -error, __FUNCTION__);
 585                 nlmsvc_insert_block(block, 10 * HZ);
 586                 goto out_unlock;
 587         }
 588
 589 callback:
 590         /* Lock was granted by VFS. */
 591         dprintk("lockd: GRANTing blocked lock.\n");
 592         block->b_granted = 1;
 593
 594         /* Schedule next grant callback in 30 seconds */
 595         nlmsvc_insert_block(block, 30 * HZ);
 596
 597         /* Call the client */
 598         kref_get(&block->b_count);
 599         if (nlm_async_call(block->b_call, NLMPROC_GRANTED_MSG,
 600                                                 &nlmsvc_grant_ops) < 0)
 601                 nlmsvc_release_block(block);
 602 out_unlock:
 603         up(&file->f_sema);
 604 }
 605
 606 /*
 607  * This is the callback from the RPC layer when the NLM_GRANTED_MSG
 608  * RPC call has succeeded or timed out.
 609  * Like all RPC callbacks, it is invoked by the rpciod process, so it
 610  * better not sleep. Therefore, we put the blocked lock on the nlm_blocked
 611  * chain once more in order to have it removed by lockd itself (which can
 612  * then sleep on the file semaphore without disrupting e.g. the nfs client).
 613  */
 614 static void nlmsvc_grant_callback(struct rpc_task *task, void *data)
 615 {
 616         struct nlm_rqst         *call = data;
 617         struct nlm_block        *block = call->a_block;
 618         unsigned long           timeout;
 619
 620         dprintk("lockd: GRANT_MSG RPC callback\n");
 621
 622         /* Technically, we should down the file semaphore here. Since we
 623          * move the block towards the head of the queue only, no harm
 624          * can be done, though. */
 625         if (task->tk_status < 0) {
 626                 /* RPC error: Re-insert for retransmission */
 627                 timeout = 10 * HZ;
 628         } else if (block->b_done) {
 629                 /* Block already removed, kill it for real */
 630                 timeout = 0;
 631         } else {
 632                 /* Call was successful, now wait for client callback */
 633                 timeout = 60 * HZ;
 634         }
 635         nlmsvc_insert_block(block, timeout);
 636         svc_wake_up(block->b_daemon);
 637 }
 638
 639 void nlmsvc_grant_release(void *data)
 640 {
 641         struct nlm_rqst         *call = data;
 642
 643         nlmsvc_release_block(call->a_block);
 644 }
 645
 646 static const struct rpc_call_ops nlmsvc_grant_ops = {
 647         .rpc_call_done = nlmsvc_grant_callback,
 648         .rpc_release = nlmsvc_grant_release,
 649 };
 650
 651 /*
 652  * We received a GRANT_RES callback. Try to find the corresponding
 653  * block.
 654  */
 655 void
 656 nlmsvc_grant_reply(struct svc_rqst *rqstp, struct nlm_cookie *cookie, u32 status)
 657 {
 658         struct nlm_block        *block;
 659         struct nlm_file         *file;
 660
 661         dprintk("grant_reply: looking for cookie %x, host (%08x), s=%d \n",
 662                 *(unsigned int *)(cookie->data),
 663                 ntohl(rqstp->rq_addr.sin_addr.s_addr), status);
 664         if (!(block = nlmsvc_find_block(cookie, &rqstp->rq_addr)))
 665                 return;
 666         file = block->b_file;
 667
 668         file->f_count++;
 669         down(&file->f_sema);
 670         if (block) {
 671                 if (status == NLM_LCK_DENIED_GRACE_PERIOD) {
 672                         /* Try again in a couple of seconds */
 673                         nlmsvc_insert_block(block, 10 * HZ);
 674                 } else {
 675                         /* Lock is now held by client, or has been rejected.
 676                          * In both cases, the block should be removed. */
 677                         nlmsvc_unlink_block(block);
 678                 }
 679         }
 680         up(&file->f_sema);
 681         nlm_release_file(file);
 682         nlmsvc_release_block(block);
 683 }
 684
 685 /*
 686  * Retry all blocked locks that have been notified. This is where lockd
 687  * picks up locks that can be granted, or grant notifications that must
 688  * be retransmitted.
 689  */
 690 unsigned long
 691 nlmsvc_retry_blocked(void)
 692 {
 693         struct nlm_block        *block;
 694
 695         dprintk("nlmsvc_retry_blocked(%p, when=%ld)\n",
 696                         nlm_blocked,
 697                         nlm_blocked? nlm_blocked->b_when : 0);
 698         while ((block = nlm_blocked) != 0) {
 699                 if (block->b_when == NLM_NEVER)
 700                         break;
 701                 if (time_after(block->b_when,jiffies))
 702                         break;
 703                 dprintk("nlmsvc_retry_blocked(%p, when=%ld, done=%d)\n",
 704                         block, block->b_when, block->b_done);
 705                 kref_get(&block->b_count);
 706                 if (block->b_done)
 707                         nlmsvc_unlink_block(block);
 708                 else
 709                         nlmsvc_grant_blocked(block);
 710                 nlmsvc_release_block(block);
 711         }
 712
 713         if ((block = nlm_blocked) && block->b_when != NLM_NEVER)
 714                 return (block->b_when - jiffies);
 715
 716         return MAX_SCHEDULE_TIMEOUT;
 717 }