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/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 int      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 struct nlm_block *       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 **bp, *b;
  61
  62         dprintk("lockd: nlmsvc_insert_block(%p, %ld)\n", block, when);
  63         kref_get(&block->b_count);
  64         if (block->b_queued)
  65                 nlmsvc_remove_block(block);
  66         bp = &nlm_blocked;
  67         if (when != NLM_NEVER) {
  68                 if ((when += jiffies) == NLM_NEVER)
  69                         when ++;
  70                 while ((b = *bp) && time_before_eq(b->b_when,when) && b->b_when != NLM_NEVER)
  71                         bp = &b->b_next;
  72         } else
  73                 while ((b = *bp) != 0)
  74                         bp = &b->b_next;
  75
  76         block->b_queued = 1;
  77         block->b_when = when;
  78         block->b_next = b;
  79         *bp = block;
  80 }
  81
  82 /*
  83  * Remove a block from the global list
  84  */
  85 static int
  86 nlmsvc_remove_block(struct nlm_block *block)
  87 {
  88         struct nlm_block **bp, *b;
  89
  90         if (!block->b_queued)
  91                 return 1;
  92         for (bp = &nlm_blocked; (b = *bp) != 0; bp = &b->b_next) {
  93                 if (b == block) {
  94                         *bp = block->b_next;
  95                         block->b_queued = 0;
  96                         nlmsvc_release_block(block);
  97                         return 1;
  98                 }
  99         }
 100
 101         return 0;
 102 }
 103
 104 /*
 105  * Find a block for a given lock
 106  */
 107 static struct nlm_block *
 108 nlmsvc_lookup_block(struct nlm_file *file, struct nlm_lock *lock)
 109 {
 110         struct nlm_block        **head, *block;
 111         struct file_lock        *fl;
 112
 113         dprintk("lockd: nlmsvc_lookup_block f=%p pd=%d %Ld-%Ld ty=%d\n",
 114                                 file, lock->fl.fl_pid,
 115                                 (long long)lock->fl.fl_start,
 116                                 (long long)lock->fl.fl_end, lock->fl.fl_type);
 117         for (head = &nlm_blocked; (block = *head) != 0; head = &block->b_next) {
 118                 fl = &block->b_call->a_args.lock.fl;
 119                 dprintk("lockd: check f=%p pd=%d %Ld-%Ld ty=%d cookie=%s\n",
 120                                 block->b_file, fl->fl_pid,
 121                                 (long long)fl->fl_start,
 122                                 (long long)fl->fl_end, fl->fl_type,
 123                                 nlmdbg_cookie2a(&block->b_call->a_args.cookie));
 124                 if (block->b_file == file && nlm_compare_locks(fl, &lock->fl)) {
 125                         kref_get(&block->b_count);
 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         if (block != NULL)
 159                 kref_get(&block->b_count);
 160         return block;
 161 }
 162
 163 /*
 164  * Create a block and initialize it.
 165  *
 166  * Note: we explicitly set the cookie of the grant reply to that of
 167  * the blocked lock request. The spec explicitly mentions that the client
 168  * should _not_ rely on the callback containing the same cookie as the
 169  * request, but (as I found out later) that's because some implementations
 170  * do just this. Never mind the standards comittees, they support our
 171  * logging industries.
 172  */
 173 static inline struct nlm_block *
 174 nlmsvc_create_block(struct svc_rqst *rqstp, struct nlm_file *file,
 175                                 struct nlm_lock *lock, struct nlm_cookie *cookie)
 176 {
 177         struct nlm_block        *block;
 178         struct nlm_host         *host;
 179         struct nlm_rqst         *call = NULL;
 180
 181         /* Create host handle for callback */
 182         host = nlmsvc_lookup_host(rqstp);
 183         if (host == NULL)
 184                 return NULL;
 185
 186         call = nlm_alloc_call(host);
 187         if (call == NULL)
 188                 return NULL;
 189
 190         /* Allocate memory for block, and initialize arguments */
 191         block = kzalloc(sizeof(*block), GFP_KERNEL);
 192         if (block == NULL)
 193                 goto failed;
 194         kref_init(&block->b_count);
 195
 196         if (!nlmsvc_setgrantargs(call, lock))
 197                 goto failed_free;
 198
 199         /* Set notifier function for VFS, and init args */
 200         call->a_args.lock.fl.fl_flags |= FL_SLEEP;
 201         call->a_args.lock.fl.fl_lmops = &nlmsvc_lock_operations;
 202         call->a_args.cookie = *cookie;  /* see above */
 203
 204         dprintk("lockd: created block %p...\n", block);
 205
 206         /* Create and initialize the block */
 207         block->b_daemon = rqstp->rq_server;
 208         block->b_host   = host;
 209         block->b_file   = file;
 210         file->f_count++;
 211
 212         /* Add to file's list of blocks */
 213         block->b_fnext  = file->f_blocks;
 214         file->f_blocks  = block;
 215
 216         /* Set up RPC arguments for callback */
 217         block->b_call = call;
 218         call->a_flags   = RPC_TASK_ASYNC;
 219         call->a_block = block;
 220
 221         return block;
 222
 223 failed_free:
 224         kfree(block);
 225 failed:
 226         nlm_release_call(call);
 227         return NULL;
 228 }
 229
 230 /*
 231  * Delete a block. If the lock was cancelled or the grant callback
 232  * failed, unlock is set to 1.
 233  * It is the caller's responsibility to check whether the file
 234  * can be closed hereafter.
 235  */
 236 static int nlmsvc_unlink_block(struct nlm_block *block)
 237 {
 238         int status;
 239         dprintk("lockd: unlinking block %p...\n", block);
 240
 241         /* Remove block from list */
 242         status = posix_unblock_lock(block->b_file->f_file, &block->b_call->a_args.lock.fl);
 243         nlmsvc_remove_block(block);
 244         return status;
 245 }
 246
 247 static void nlmsvc_free_block(struct kref *kref)
 248 {
 249         struct nlm_block *block = container_of(kref, struct nlm_block, b_count);
 250         struct nlm_file         *file = block->b_file;
 251         struct nlm_block        **bp;
 252
 253         dprintk("lockd: freeing block %p...\n", block);
 254
 255         down(&file->f_sema);
 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         up(&file->f_sema);
 264
 265         nlmsvc_freegrantargs(block->b_call);
 266         nlm_release_call(block->b_call);
 267         nlm_release_file(block->b_file);
 268         kfree(block);
 269 }
 270
 271 static void nlmsvc_release_block(struct nlm_block *block)
 272 {
 273         if (block != NULL)
 274                 kref_put(&block->b_count, nlmsvc_free_block);
 275 }
 276
 277 static void nlmsvc_act_mark(struct nlm_host *host, struct nlm_file *file)
 278 {
 279         struct nlm_block *block;
 280
 281         down(&file->f_sema);
 282         for (block = file->f_blocks; block != NULL; block = block->b_fnext)
 283                 block->b_host->h_inuse = 1;
 284         up(&file->f_sema);
 285 }
 286
 287 static void nlmsvc_act_unlock(struct nlm_host *host, struct nlm_file *file)
 288 {
 289         struct nlm_block *block;
 290
 291 restart:
 292         down(&file->f_sema);
 293         for (block = file->f_blocks; block != NULL; block = block->b_fnext) {
 294                 if (host != NULL && host != block->b_host)
 295                         continue;
 296                 if (!block->b_queued)
 297                         continue;
 298                 kref_get(&block->b_count);
 299                 up(&file->f_sema);
 300                 nlmsvc_unlink_block(block);
 301                 nlmsvc_release_block(block);
 302                 goto restart;
 303         }
 304         up(&file->f_sema);
 305 }
 306
 307 /*
 308  * Loop over all blocks and perform the action specified.
 309  * (NLM_ACT_CHECK handled by nlmsvc_inspect_file).
 310  */
 311 void
 312 nlmsvc_traverse_blocks(struct nlm_host *host, struct nlm_file *file, int action)
 313 {
 314         if (action == NLM_ACT_MARK)
 315                 nlmsvc_act_mark(host, file);
 316         else
 317                 nlmsvc_act_unlock(host, file);
 318 }
 319
 320 /*
 321  * Initialize arguments for GRANTED call. The nlm_rqst structure
 322  * has been cleared already.
 323  */
 324 static int nlmsvc_setgrantargs(struct nlm_rqst *call, struct nlm_lock *lock)
 325 {
 326         locks_copy_lock(&call->a_args.lock.fl, &lock->fl);
 327         memcpy(&call->a_args.lock.fh, &lock->fh, sizeof(call->a_args.lock.fh));
 328         call->a_args.lock.caller = system_utsname.nodename;
 329         call->a_args.lock.oh.len = lock->oh.len;
 330
 331         /* set default data area */
 332         call->a_args.lock.oh.data = call->a_owner;
 333         call->a_args.lock.svid = lock->fl.fl_pid;
 334
 335         if (lock->oh.len > NLMCLNT_OHSIZE) {
 336                 void *data = kmalloc(lock->oh.len, GFP_KERNEL);
 337                 if (!data)
 338                         return 0;
 339                 call->a_args.lock.oh.data = (u8 *) data;
 340         }
 341
 342         memcpy(call->a_args.lock.oh.data, lock->oh.data, lock->oh.len);
 343         return 1;
 344 }
 345
 346 static void nlmsvc_freegrantargs(struct nlm_rqst *call)
 347 {
 348         if (call->a_args.lock.oh.data != call->a_owner)
 349                 kfree(call->a_args.lock.oh.data);
 350 }
 351
 352 /*
 353  * Attempt to establish a lock, and if it can't be granted, block it
 354  * if required.
 355  */
 356 u32
 357 nlmsvc_lock(struct svc_rqst *rqstp, struct nlm_file *file,
 358                         struct nlm_lock *lock, int wait, struct nlm_cookie *cookie)
 359 {
 360         struct nlm_block        *block, *newblock = NULL;
 361         int                     error;
 362         u32                     ret;
 363
 364         dprintk("lockd: nlmsvc_lock(%s/%ld, ty=%d, pi=%d, %Ld-%Ld, bl=%d)\n",
 365                                 file->f_file->f_dentry->d_inode->i_sb->s_id,
 366                                 file->f_file->f_dentry->d_inode->i_ino,
 367                                 lock->fl.fl_type, lock->fl.fl_pid,
 368                                 (long long)lock->fl.fl_start,
 369                                 (long long)lock->fl.fl_end,
 370                                 wait);
 371
 372
 373         lock->fl.fl_flags &= ~FL_SLEEP;
 374 again:
 375         /* Lock file against concurrent access */
 376         down(&file->f_sema);
 377         /* Get existing block (in case client is busy-waiting) */
 378         block = nlmsvc_lookup_block(file, lock);
 379         if (block == NULL) {
 380                 if (newblock != NULL)
 381                         lock = &newblock->b_call->a_args.lock;
 382         } else
 383                 lock = &block->b_call->a_args.lock;
 384
 385         error = posix_lock_file(file->f_file, &lock->fl);
 386         lock->fl.fl_flags &= ~FL_SLEEP;
 387
 388         dprintk("lockd: posix_lock_file returned %d\n", error);
 389
 390         switch(error) {
 391                 case 0:
 392                         ret = nlm_granted;
 393                         goto out;
 394                 case -EAGAIN:
 395                         break;
 396                 case -EDEADLK:
 397                         ret = nlm_deadlock;
 398                         goto out;
 399                 default:                        /* includes ENOLCK */
 400                         ret = nlm_lck_denied_nolocks;
 401                         goto out;
 402         }
 403
 404         ret = nlm_lck_denied;
 405         if (!wait)
 406                 goto out;
 407
 408         ret = nlm_lck_blocked;
 409         if (block != NULL)
 410                 goto out;
 411
 412         /* If we don't have a block, create and initialize it. Then
 413          * retry because we may have slept in kmalloc. */
 414         /* We have to release f_sema as nlmsvc_create_block may try to
 415          * to claim it while doing host garbage collection */
 416         if (newblock == NULL) {
 417                 up(&file->f_sema);
 418                 dprintk("lockd: blocking on this lock (allocating).\n");
 419                 if (!(newblock = nlmsvc_create_block(rqstp, file, lock, cookie)))
 420                         return nlm_lck_denied_nolocks;
 421                 goto again;
 422         }
 423
 424         /* Append to list of blocked */
 425         nlmsvc_insert_block(newblock, NLM_NEVER);
 426 out:
 427         up(&file->f_sema);
 428         nlmsvc_release_block(newblock);
 429         nlmsvc_release_block(block);
 430         dprintk("lockd: nlmsvc_lock returned %u\n", ret);
 431         return ret;
 432 }
 433
 434 /*
 435  * Test for presence of a conflicting lock.
 436  */
 437 u32
 438 nlmsvc_testlock(struct nlm_file *file, struct nlm_lock *lock,
 439                                        struct nlm_lock *conflock)
 440 {
 441         dprintk("lockd: nlmsvc_testlock(%s/%ld, ty=%d, %Ld-%Ld)\n",
 442                                 file->f_file->f_dentry->d_inode->i_sb->s_id,
 443                                 file->f_file->f_dentry->d_inode->i_ino,
 444                                 lock->fl.fl_type,
 445                                 (long long)lock->fl.fl_start,
 446                                 (long long)lock->fl.fl_end);
 447
 448         if (posix_test_lock(file->f_file, &lock->fl, &conflock->fl)) {
 449                 dprintk("lockd: conflicting lock(ty=%d, %Ld-%Ld)\n",
 450                                 conflock->fl.fl_type,
 451                                 (long long)conflock->fl.fl_start,
 452                                 (long long)conflock->fl.fl_end);
 453                 conflock->caller = "somehost";  /* FIXME */
 454                 conflock->oh.len = 0;           /* don't return OH info */
 455                 conflock->svid = conflock->fl.fl_pid;
 456                 return nlm_lck_denied;
 457         }
 458
 459         return nlm_granted;
 460 }
 461
 462 /*
 463  * Remove a lock.
 464  * This implies a CANCEL call: We send a GRANT_MSG, the client replies
 465  * with a GRANT_RES call which gets lost, and calls UNLOCK immediately
 466  * afterwards. In this case the block will still be there, and hence
 467  * must be removed.
 468  */
 469 u32
 470 nlmsvc_unlock(struct nlm_file *file, struct nlm_lock *lock)
 471 {
 472         int     error;
 473
 474         dprintk("lockd: nlmsvc_unlock(%s/%ld, pi=%d, %Ld-%Ld)\n",
 475                                 file->f_file->f_dentry->d_inode->i_sb->s_id,
 476                                 file->f_file->f_dentry->d_inode->i_ino,
 477                                 lock->fl.fl_pid,
 478                                 (long long)lock->fl.fl_start,
 479                                 (long long)lock->fl.fl_end);
 480
 481         /* First, cancel any lock that might be there */
 482         nlmsvc_cancel_blocked(file, lock);
 483
 484         lock->fl.fl_type = F_UNLCK;
 485         error = posix_lock_file(file->f_file, &lock->fl);
 486
 487         return (error < 0)? nlm_lck_denied_nolocks : nlm_granted;
 488 }
 489
 490 /*
 491  * Cancel a previously blocked request.
 492  *
 493  * A cancel request always overrides any grant that may currently
 494  * be in progress.
 495  * The calling procedure must check whether the file can be closed.
 496  */
 497 u32
 498 nlmsvc_cancel_blocked(struct nlm_file *file, struct nlm_lock *lock)
 499 {
 500         struct nlm_block        *block;
 501         int status = 0;
 502
 503         dprintk("lockd: nlmsvc_cancel(%s/%ld, pi=%d, %Ld-%Ld)\n",
 504                                 file->f_file->f_dentry->d_inode->i_sb->s_id,
 505                                 file->f_file->f_dentry->d_inode->i_ino,
 506                                 lock->fl.fl_pid,
 507                                 (long long)lock->fl.fl_start,
 508                                 (long long)lock->fl.fl_end);
 509
 510         down(&file->f_sema);
 511         block = nlmsvc_lookup_block(file, lock);
 512         up(&file->f_sema);
 513         if (block != NULL) {
 514                 status = nlmsvc_unlink_block(block);
 515                 nlmsvc_release_block(block);
 516         }
 517         return status ? nlm_lck_denied : nlm_granted;
 518 }
 519
 520 /*
 521  * Unblock a blocked lock request. This is a callback invoked from the
 522  * VFS layer when a lock on which we blocked is removed.
 523  *
 524  * This function doesn't grant the blocked lock instantly, but rather moves
 525  * the block to the head of nlm_blocked where it can be picked up by lockd.
 526  */
 527 static void
 528 nlmsvc_notify_blocked(struct file_lock *fl)
 529 {
 530         struct nlm_block        **bp, *block;
 531
 532         dprintk("lockd: VFS unblock notification for block %p\n", fl);
 533         for (bp = &nlm_blocked; (block = *bp) != 0; bp = &block->b_next) {
 534                 if (nlm_compare_locks(&block->b_call->a_args.lock.fl, fl)) {
 535                         nlmsvc_insert_block(block, 0);
 536                         svc_wake_up(block->b_daemon);
 537                         return;
 538                 }
 539         }
 540
 541         printk(KERN_WARNING "lockd: notification for unknown block!\n");
 542 }
 543
 544 static int nlmsvc_same_owner(struct file_lock *fl1, struct file_lock *fl2)
 545 {
 546         return fl1->fl_owner == fl2->fl_owner && fl1->fl_pid == fl2->fl_pid;
 547 }
 548
 549 struct lock_manager_operations nlmsvc_lock_operations = {
 550         .fl_compare_owner = nlmsvc_same_owner,
 551         .fl_notify = nlmsvc_notify_blocked,
 552 };
 553
 554 /*
 555  * Try to claim a lock that was previously blocked.
 556  *
 557  * Note that we use both the RPC_GRANTED_MSG call _and_ an async
 558  * RPC thread when notifying the client. This seems like overkill...
 559  * Here's why:
 560  *  -   we don't want to use a synchronous RPC thread, otherwise
 561  *      we might find ourselves hanging on a dead portmapper.
 562  *  -   Some lockd implementations (e.g. HP) don't react to
 563  *      RPC_GRANTED calls; they seem to insist on RPC_GRANTED_MSG calls.
 564  */
 565 static void
 566 nlmsvc_grant_blocked(struct nlm_block *block)
 567 {
 568         struct nlm_file         *file = block->b_file;
 569         struct nlm_lock         *lock = &block->b_call->a_args.lock;
 570         int                     error;
 571
 572         dprintk("lockd: grant blocked lock %p\n", block);
 573
 574         /* Unlink block request from list */
 575         nlmsvc_unlink_block(block);
 576
 577         /* If b_granted is true this means we've been here before.
 578          * Just retry the grant callback, possibly refreshing the RPC
 579          * binding */
 580         if (block->b_granted) {
 581                 nlm_rebind_host(block->b_host);
 582                 goto callback;
 583         }
 584
 585         /* Try the lock operation again */
 586         lock->fl.fl_flags |= FL_SLEEP;
 587         error = posix_lock_file(file->f_file, &lock->fl);
 588         lock->fl.fl_flags &= ~FL_SLEEP;
 589
 590         switch (error) {
 591         case 0:
 592                 break;
 593         case -EAGAIN:
 594                 dprintk("lockd: lock still blocked\n");
 595                 nlmsvc_insert_block(block, NLM_NEVER);
 596                 return;
 597         default:
 598                 printk(KERN_WARNING "lockd: unexpected error %d in %s!\n",
 599                                 -error, __FUNCTION__);
 600                 nlmsvc_insert_block(block, 10 * HZ);
 601                 return;
 602         }
 603
 604 callback:
 605         /* Lock was granted by VFS. */
 606         dprintk("lockd: GRANTing blocked lock.\n");
 607         block->b_granted = 1;
 608
 609         /* Schedule next grant callback in 30 seconds */
 610         nlmsvc_insert_block(block, 30 * HZ);
 611
 612         /* Call the client */
 613         kref_get(&block->b_count);
 614         if (nlm_async_call(block->b_call, NLMPROC_GRANTED_MSG,
 615                                                 &nlmsvc_grant_ops) < 0)
 616                 nlmsvc_release_block(block);
 617 }
 618
 619 /*
 620  * This is the callback from the RPC layer when the NLM_GRANTED_MSG
 621  * RPC call has succeeded or timed out.
 622  * Like all RPC callbacks, it is invoked by the rpciod process, so it
 623  * better not sleep. Therefore, we put the blocked lock on the nlm_blocked
 624  * chain once more in order to have it removed by lockd itself (which can
 625  * then sleep on the file semaphore without disrupting e.g. the nfs client).
 626  */
 627 static void nlmsvc_grant_callback(struct rpc_task *task, void *data)
 628 {
 629         struct nlm_rqst         *call = data;
 630         struct nlm_block        *block = call->a_block;
 631         unsigned long           timeout;
 632
 633         dprintk("lockd: GRANT_MSG RPC callback\n");
 634
 635         /* Technically, we should down the file semaphore here. Since we
 636          * move the block towards the head of the queue only, no harm
 637          * can be done, though. */
 638         if (task->tk_status < 0) {
 639                 /* RPC error: Re-insert for retransmission */
 640                 timeout = 10 * HZ;
 641         } else {
 642                 /* Call was successful, now wait for client callback */
 643                 timeout = 60 * HZ;
 644         }
 645         nlmsvc_insert_block(block, timeout);
 646         svc_wake_up(block->b_daemon);
 647 }
 648
 649 static void nlmsvc_grant_release(void *data)
 650 {
 651         struct nlm_rqst         *call = data;
 652
 653         nlmsvc_release_block(call->a_block);
 654 }
 655
 656 static const struct rpc_call_ops nlmsvc_grant_ops = {
 657         .rpc_call_done = nlmsvc_grant_callback,
 658         .rpc_release = nlmsvc_grant_release,
 659 };
 660
 661 /*
 662  * We received a GRANT_RES callback. Try to find the corresponding
 663  * block.
 664  */
 665 void
 666 nlmsvc_grant_reply(struct svc_rqst *rqstp, struct nlm_cookie *cookie, u32 status)
 667 {
 668         struct nlm_block        *block;
 669         struct nlm_file         *file;
 670
 671         dprintk("grant_reply: looking for cookie %x, host (%08x), s=%d \n",
 672                 *(unsigned int *)(cookie->data),
 673                 ntohl(rqstp->rq_addr.sin_addr.s_addr), status);
 674         if (!(block = nlmsvc_find_block(cookie, &rqstp->rq_addr)))
 675                 return;
 676         file = block->b_file;
 677
 678         if (block) {
 679                 if (status == NLM_LCK_DENIED_GRACE_PERIOD) {
 680                         /* Try again in a couple of seconds */
 681                         nlmsvc_insert_block(block, 10 * HZ);
 682                 } else {
 683                         /* Lock is now held by client, or has been rejected.
 684                          * In both cases, the block should be removed. */
 685                         nlmsvc_unlink_block(block);
 686                 }
 687         }
 688         nlmsvc_release_block(block);
 689 }
 690
 691 /*
 692  * Retry all blocked locks that have been notified. This is where lockd
 693  * picks up locks that can be granted, or grant notifications that must
 694  * be retransmitted.
 695  */
 696 unsigned long
 697 nlmsvc_retry_blocked(void)
 698 {
 699         struct nlm_block        *block;
 700
 701         dprintk("nlmsvc_retry_blocked(%p, when=%ld)\n",
 702                         nlm_blocked,
 703                         nlm_blocked? nlm_blocked->b_when : 0);
 704         while ((block = nlm_blocked) != 0) {
 705                 if (block->b_when == NLM_NEVER)
 706                         break;
 707                 if (time_after(block->b_when,jiffies))
 708                         break;
 709                 dprintk("nlmsvc_retry_blocked(%p, when=%ld)\n",
 710                         block, block->b_when);
 711                 kref_get(&block->b_count);
 712                 nlmsvc_grant_blocked(block);
 713                 nlmsvc_release_block(block);
 714         }
 715
 716         if ((block = nlm_blocked) && block->b_when != NLM_NEVER)
 717                 return (block->b_when - jiffies);
 718
 719         return MAX_SCHEDULE_TIMEOUT;
 720 }