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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;
 186
 187         /* Create host handle for callback */
 188         host = nlmsvc_lookup_host(rqstp);
 189         if (host == NULL)
 190                 return NULL;
 191
 192         /* Allocate memory for block, and initialize arguments */
 193         if (!(block = (struct nlm_block *) kmalloc(sizeof(*block), GFP_KERNEL)))
 194                 goto failed;
 195         memset(block, 0, sizeof(*block));
 196         locks_init_lock(&block->b_call.a_args.lock.fl);
 197         locks_init_lock(&block->b_call.a_res.lock.fl);
 198         kref_init(&block->b_count);
 199
 200         if (!nlmsvc_setgrantargs(&block->b_call, lock))
 201                 goto failed_free;
 202
 203         /* Set notifier function for VFS, and init args */
 204         block->b_call.a_args.lock.fl.fl_flags |= FL_SLEEP;
 205         block->b_call.a_args.lock.fl.fl_lmops = &nlmsvc_lock_operations;
 206         block->b_call.a_args.cookie = *cookie;  /* see above */
 207
 208         dprintk("lockd: created block %p...\n", block);
 209
 210         /* Create and initialize the block */
 211         block->b_daemon = rqstp->rq_server;
 212         block->b_host   = host;
 213         block->b_file   = file;
 214
 215         /* Add to file's list of blocks */
 216         block->b_fnext  = file->f_blocks;
 217         file->f_blocks  = block;
 218
 219         /* Set up RPC arguments for callback */
 220         call = &block->b_call;
 221         call->a_host    = host;
 222         call->a_flags   = RPC_TASK_ASYNC;
 223
 224         return block;
 225
 226 failed_free:
 227         kfree(block);
 228 failed:
 229         nlm_release_host(host);
 230         return NULL;
 231 }
 232
 233 /*
 234  * Delete a block. If the lock was cancelled or the grant callback
 235  * failed, unlock is set to 1.
 236  * It is the caller's responsibility to check whether the file
 237  * can be closed hereafter.
 238  */
 239 static int nlmsvc_unlink_block(struct nlm_block *block)
 240 {
 241         int status;
 242         dprintk("lockd: unlinking block %p...\n", block);
 243
 244         /* Remove block from list */
 245         status = posix_unblock_lock(block->b_file->f_file, &block->b_call.a_args.lock.fl);
 246         nlmsvc_remove_block(block);
 247         return status;
 248 }
 249
 250 static void nlmsvc_free_block(struct kref *kref)
 251 {
 252         struct nlm_block *block = container_of(kref, struct nlm_block, b_count);
 253         struct nlm_file         *file = block->b_file;
 254         struct nlm_block        **bp;
 255
 256         dprintk("lockd: freeing block %p...\n", block);
 257
 258         /* Remove block from file's list of blocks */
 259         for (bp = &file->f_blocks; *bp; bp = &(*bp)->b_fnext) {
 260                 if (*bp == block) {
 261                         *bp = block->b_fnext;
 262                         break;
 263                 }
 264         }
 265
 266         if (block->b_host)
 267                 nlm_release_host(block->b_host);
 268         nlmsvc_freegrantargs(&block->b_call);
 269         kfree(block);
 270 }
 271
 272 static void nlmsvc_release_block(struct nlm_block *block)
 273 {
 274         if (block != NULL)
 275                 kref_put(&block->b_count, nlmsvc_free_block);
 276 }
 277
 278 /*
 279  * Loop over all blocks and perform the action specified.
 280  * (NLM_ACT_CHECK handled by nlmsvc_inspect_file).
 281  */
 282 int
 283 nlmsvc_traverse_blocks(struct nlm_host *host, struct nlm_file *file, int action)
 284 {
 285         struct nlm_block        *block, *next;
 286         /* XXX: Will everything get cleaned up if we don't unlock here? */
 287
 288         down(&file->f_sema);
 289         for (block = file->f_blocks; block; block = next) {
 290                 next = block->b_fnext;
 291                 if (action == NLM_ACT_MARK)
 292                         block->b_host->h_inuse = 1;
 293                 else if (action == NLM_ACT_UNLOCK) {
 294                         if (host == NULL || host == block->b_host)
 295                                 nlmsvc_unlink_block(block);
 296                 }
 297         }
 298         up(&file->f_sema);
 299         return 0;
 300 }
 301
 302 /*
 303  * Initialize arguments for GRANTED call. The nlm_rqst structure
 304  * has been cleared already.
 305  */
 306 static int nlmsvc_setgrantargs(struct nlm_rqst *call, struct nlm_lock *lock)
 307 {
 308         locks_copy_lock(&call->a_args.lock.fl, &lock->fl);
 309         memcpy(&call->a_args.lock.fh, &lock->fh, sizeof(call->a_args.lock.fh));
 310         call->a_args.lock.caller = system_utsname.nodename;
 311         call->a_args.lock.oh.len = lock->oh.len;
 312
 313         /* set default data area */
 314         call->a_args.lock.oh.data = call->a_owner;
 315         call->a_args.lock.svid = lock->fl.fl_pid;
 316
 317         if (lock->oh.len > NLMCLNT_OHSIZE) {
 318                 void *data = kmalloc(lock->oh.len, GFP_KERNEL);
 319                 if (!data) {
 320                         nlmsvc_freegrantargs(call);
 321                         return 0;
 322                 }
 323                 call->a_args.lock.oh.data = (u8 *) data;
 324         }
 325
 326         memcpy(call->a_args.lock.oh.data, lock->oh.data, lock->oh.len);
 327         return 1;
 328 }
 329
 330 static void nlmsvc_freegrantargs(struct nlm_rqst *call)
 331 {
 332         struct file_lock *fl = &call->a_args.lock.fl;
 333         /*
 334          * Check whether we allocated memory for the owner.
 335          */
 336         if (call->a_args.lock.oh.data != (u8 *) call->a_owner) {
 337                 kfree(call->a_args.lock.oh.data);
 338         }
 339         if (fl->fl_ops && fl->fl_ops->fl_release_private)
 340                 fl->fl_ops->fl_release_private(fl);
 341         if (fl->fl_lmops && fl->fl_lmops->fl_release_private)
 342                 fl->fl_lmops->fl_release_private(fl);
 343 }
 344
 345 /*
 346  * Attempt to establish a lock, and if it can't be granted, block it
 347  * if required.
 348  */
 349 u32
 350 nlmsvc_lock(struct svc_rqst *rqstp, struct nlm_file *file,
 351                         struct nlm_lock *lock, int wait, struct nlm_cookie *cookie)
 352 {
 353         struct nlm_block        *block, *newblock = NULL;
 354         int                     error;
 355         u32                     ret;
 356
 357         dprintk("lockd: nlmsvc_lock(%s/%ld, ty=%d, pi=%d, %Ld-%Ld, bl=%d)\n",
 358                                 file->f_file->f_dentry->d_inode->i_sb->s_id,
 359                                 file->f_file->f_dentry->d_inode->i_ino,
 360                                 lock->fl.fl_type, lock->fl.fl_pid,
 361                                 (long long)lock->fl.fl_start,
 362                                 (long long)lock->fl.fl_end,
 363                                 wait);
 364
 365
 366         lock->fl.fl_flags &= ~FL_SLEEP;
 367 again:
 368         /* Lock file against concurrent access */
 369         down(&file->f_sema);
 370         /* Get existing block (in case client is busy-waiting) */
 371         block = nlmsvc_lookup_block(file, lock, 0);
 372         if (block == NULL) {
 373                 if (newblock != NULL)
 374                         lock = &newblock->b_call.a_args.lock;
 375         } else
 376                 lock = &block->b_call.a_args.lock;
 377
 378         error = posix_lock_file(file->f_file, &lock->fl);
 379         lock->fl.fl_flags &= ~FL_SLEEP;
 380
 381         dprintk("lockd: posix_lock_file returned %d\n", error);
 382
 383         switch(error) {
 384                 case 0:
 385                         ret = nlm_granted;
 386                         goto out;
 387                 case -EAGAIN:
 388                         break;
 389                 case -EDEADLK:
 390                         ret = nlm_deadlock;
 391                         goto out;
 392                 default:                        /* includes ENOLCK */
 393                         ret = nlm_lck_denied_nolocks;
 394                         goto out;
 395         }
 396
 397         ret = nlm_lck_denied;
 398         if (!wait)
 399                 goto out;
 400
 401         ret = nlm_lck_blocked;
 402         if (block != NULL)
 403                 goto out;
 404
 405         /* If we don't have a block, create and initialize it. Then
 406          * retry because we may have slept in kmalloc. */
 407         /* We have to release f_sema as nlmsvc_create_block may try to
 408          * to claim it while doing host garbage collection */
 409         if (newblock == NULL) {
 410                 up(&file->f_sema);
 411                 dprintk("lockd: blocking on this lock (allocating).\n");
 412                 if (!(newblock = nlmsvc_create_block(rqstp, file, lock, cookie)))
 413                         return nlm_lck_denied_nolocks;
 414                 goto again;
 415         }
 416
 417         /* Append to list of blocked */
 418         nlmsvc_insert_block(newblock, NLM_NEVER);
 419 out:
 420         up(&file->f_sema);
 421         nlmsvc_release_block(newblock);
 422         nlmsvc_release_block(block);
 423         dprintk("lockd: nlmsvc_lock returned %u\n", ret);
 424         return ret;
 425 }
 426
 427 /*
 428  * Test for presence of a conflicting lock.
 429  */
 430 u32
 431 nlmsvc_testlock(struct nlm_file *file, struct nlm_lock *lock,
 432                                        struct nlm_lock *conflock)
 433 {
 434         dprintk("lockd: nlmsvc_testlock(%s/%ld, ty=%d, %Ld-%Ld)\n",
 435                                 file->f_file->f_dentry->d_inode->i_sb->s_id,
 436                                 file->f_file->f_dentry->d_inode->i_ino,
 437                                 lock->fl.fl_type,
 438                                 (long long)lock->fl.fl_start,
 439                                 (long long)lock->fl.fl_end);
 440
 441         if (posix_test_lock(file->f_file, &lock->fl, &conflock->fl)) {
 442                 dprintk("lockd: conflicting lock(ty=%d, %Ld-%Ld)\n",
 443                                 conflock->fl.fl_type,
 444                                 (long long)conflock->fl.fl_start,
 445                                 (long long)conflock->fl.fl_end);
 446                 conflock->caller = "somehost";  /* FIXME */
 447                 conflock->oh.len = 0;           /* don't return OH info */
 448                 conflock->svid = conflock->fl.fl_pid;
 449                 return nlm_lck_denied;
 450         }
 451
 452         return nlm_granted;
 453 }
 454
 455 /*
 456  * Remove a lock.
 457  * This implies a CANCEL call: We send a GRANT_MSG, the client replies
 458  * with a GRANT_RES call which gets lost, and calls UNLOCK immediately
 459  * afterwards. In this case the block will still be there, and hence
 460  * must be removed.
 461  */
 462 u32
 463 nlmsvc_unlock(struct nlm_file *file, struct nlm_lock *lock)
 464 {
 465         int     error;
 466
 467         dprintk("lockd: nlmsvc_unlock(%s/%ld, pi=%d, %Ld-%Ld)\n",
 468                                 file->f_file->f_dentry->d_inode->i_sb->s_id,
 469                                 file->f_file->f_dentry->d_inode->i_ino,
 470                                 lock->fl.fl_pid,
 471                                 (long long)lock->fl.fl_start,
 472                                 (long long)lock->fl.fl_end);
 473
 474         /* First, cancel any lock that might be there */
 475         nlmsvc_cancel_blocked(file, lock);
 476
 477         lock->fl.fl_type = F_UNLCK;
 478         error = posix_lock_file(file->f_file, &lock->fl);
 479
 480         return (error < 0)? nlm_lck_denied_nolocks : nlm_granted;
 481 }
 482
 483 /*
 484  * Cancel a previously blocked request.
 485  *
 486  * A cancel request always overrides any grant that may currently
 487  * be in progress.
 488  * The calling procedure must check whether the file can be closed.
 489  */
 490 u32
 491 nlmsvc_cancel_blocked(struct nlm_file *file, struct nlm_lock *lock)
 492 {
 493         struct nlm_block        *block;
 494         int status = 0;
 495
 496         dprintk("lockd: nlmsvc_cancel(%s/%ld, pi=%d, %Ld-%Ld)\n",
 497                                 file->f_file->f_dentry->d_inode->i_sb->s_id,
 498                                 file->f_file->f_dentry->d_inode->i_ino,
 499                                 lock->fl.fl_pid,
 500                                 (long long)lock->fl.fl_start,
 501                                 (long long)lock->fl.fl_end);
 502
 503         down(&file->f_sema);
 504         if ((block = nlmsvc_lookup_block(file, lock, 1)) != NULL) {
 505                 status = nlmsvc_unlink_block(block);
 506                 nlmsvc_release_block(block);
 507         }
 508         up(&file->f_sema);
 509         return status ? nlm_lck_denied : nlm_granted;
 510 }
 511
 512 /*
 513  * Unblock a blocked lock request. This is a callback invoked from the
 514  * VFS layer when a lock on which we blocked is removed.
 515  *
 516  * This function doesn't grant the blocked lock instantly, but rather moves
 517  * the block to the head of nlm_blocked where it can be picked up by lockd.
 518  */
 519 static void
 520 nlmsvc_notify_blocked(struct file_lock *fl)
 521 {
 522         struct nlm_block        **bp, *block;
 523
 524         dprintk("lockd: VFS unblock notification for block %p\n", fl);
 525         for (bp = &nlm_blocked; (block = *bp) != 0; bp = &block->b_next) {
 526                 if (nlm_compare_locks(&block->b_call.a_args.lock.fl, fl)) {
 527                         nlmsvc_insert_block(block, 0);
 528                         svc_wake_up(block->b_daemon);
 529                         return;
 530                 }
 531         }
 532
 533         printk(KERN_WARNING "lockd: notification for unknown block!\n");
 534 }
 535
 536 static int nlmsvc_same_owner(struct file_lock *fl1, struct file_lock *fl2)
 537 {
 538         return fl1->fl_owner == fl2->fl_owner && fl1->fl_pid == fl2->fl_pid;
 539 }
 540
 541 struct lock_manager_operations nlmsvc_lock_operations = {
 542         .fl_compare_owner = nlmsvc_same_owner,
 543         .fl_notify = nlmsvc_notify_blocked,
 544 };
 545
 546 /*
 547  * Try to claim a lock that was previously blocked.
 548  *
 549  * Note that we use both the RPC_GRANTED_MSG call _and_ an async
 550  * RPC thread when notifying the client. This seems like overkill...
 551  * Here's why:
 552  *  -   we don't want to use a synchronous RPC thread, otherwise
 553  *      we might find ourselves hanging on a dead portmapper.
 554  *  -   Some lockd implementations (e.g. HP) don't react to
 555  *      RPC_GRANTED calls; they seem to insist on RPC_GRANTED_MSG calls.
 556  */
 557 static void
 558 nlmsvc_grant_blocked(struct nlm_block *block)
 559 {
 560         struct nlm_file         *file = block->b_file;
 561         struct nlm_lock         *lock = &block->b_call.a_args.lock;
 562         int                     error;
 563
 564         dprintk("lockd: grant blocked lock %p\n", block);
 565
 566         /* First thing is lock the file */
 567         down(&file->f_sema);
 568
 569         /* Unlink block request from list */
 570         nlmsvc_unlink_block(block);
 571
 572         /* If b_granted is true this means we've been here before.
 573          * Just retry the grant callback, possibly refreshing the RPC
 574          * binding */
 575         if (block->b_granted) {
 576                 nlm_rebind_host(block->b_host);
 577                 goto callback;
 578         }
 579
 580         /* Try the lock operation again */
 581         lock->fl.fl_flags |= FL_SLEEP;
 582         error = posix_lock_file(file->f_file, &lock->fl);
 583         lock->fl.fl_flags &= ~FL_SLEEP;
 584
 585         switch (error) {
 586         case 0:
 587                 break;
 588         case -EAGAIN:
 589                 dprintk("lockd: lock still blocked\n");
 590                 nlmsvc_insert_block(block, NLM_NEVER);
 591                 goto out_unlock;
 592         default:
 593                 printk(KERN_WARNING "lockd: unexpected error %d in %s!\n",
 594                                 -error, __FUNCTION__);
 595                 nlmsvc_insert_block(block, 10 * HZ);
 596                 goto out_unlock;
 597         }
 598
 599 callback:
 600         /* Lock was granted by VFS. */
 601         dprintk("lockd: GRANTing blocked lock.\n");
 602         block->b_granted = 1;
 603
 604         /* Schedule next grant callback in 30 seconds */
 605         nlmsvc_insert_block(block, 30 * HZ);
 606
 607         /* Call the client */
 608         kref_get(&block->b_count);
 609         if (nlmsvc_async_call(&block->b_call, NLMPROC_GRANTED_MSG,
 610                                                 &nlmsvc_grant_ops) < 0)
 611                 nlmsvc_release_block(block);
 612 out_unlock:
 613         up(&file->f_sema);
 614 }
 615
 616 /*
 617  * This is the callback from the RPC layer when the NLM_GRANTED_MSG
 618  * RPC call has succeeded or timed out.
 619  * Like all RPC callbacks, it is invoked by the rpciod process, so it
 620  * better not sleep. Therefore, we put the blocked lock on the nlm_blocked
 621  * chain once more in order to have it removed by lockd itself (which can
 622  * then sleep on the file semaphore without disrupting e.g. the nfs client).
 623  */
 624 static void nlmsvc_grant_callback(struct rpc_task *task, void *data)
 625 {
 626         struct nlm_rqst         *call = data;
 627         struct nlm_block        *block = container_of(call, struct nlm_block, b_call);
 628         unsigned long           timeout;
 629
 630         dprintk("lockd: GRANT_MSG RPC callback\n");
 631
 632         /* Technically, we should down the file semaphore here. Since we
 633          * move the block towards the head of the queue only, no harm
 634          * can be done, though. */
 635         if (task->tk_status < 0) {
 636                 /* RPC error: Re-insert for retransmission */
 637                 timeout = 10 * HZ;
 638         } else if (block->b_done) {
 639                 /* Block already removed, kill it for real */
 640                 timeout = 0;
 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 void nlmsvc_grant_release(void *data)
 650 {
 651         nlmsvc_release_block(data);
 652 }
 653
 654 static const struct rpc_call_ops nlmsvc_grant_ops = {
 655         .rpc_call_done = nlmsvc_grant_callback,
 656         .rpc_release = nlmsvc_grant_release,
 657 };
 658
 659 /*
 660  * We received a GRANT_RES callback. Try to find the corresponding
 661  * block.
 662  */
 663 void
 664 nlmsvc_grant_reply(struct svc_rqst *rqstp, struct nlm_cookie *cookie, u32 status)
 665 {
 666         struct nlm_block        *block;
 667         struct nlm_file         *file;
 668
 669         dprintk("grant_reply: looking for cookie %x, host (%08x), s=%d \n",
 670                 *(unsigned int *)(cookie->data),
 671                 ntohl(rqstp->rq_addr.sin_addr.s_addr), status);
 672         if (!(block = nlmsvc_find_block(cookie, &rqstp->rq_addr)))
 673                 return;
 674         file = block->b_file;
 675
 676         file->f_count++;
 677         down(&file->f_sema);
 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         up(&file->f_sema);
 689         nlm_release_file(file);
 690         nlmsvc_release_block(block);
 691 }
 692
 693 /*
 694  * Retry all blocked locks that have been notified. This is where lockd
 695  * picks up locks that can be granted, or grant notifications that must
 696  * be retransmitted.
 697  */
 698 unsigned long
 699 nlmsvc_retry_blocked(void)
 700 {
 701         struct nlm_block        *block;
 702
 703         dprintk("nlmsvc_retry_blocked(%p, when=%ld)\n",
 704                         nlm_blocked,
 705                         nlm_blocked? nlm_blocked->b_when : 0);
 706         while ((block = nlm_blocked) != 0) {
 707                 if (block->b_when == NLM_NEVER)
 708                         break;
 709                 if (time_after(block->b_when,jiffies))
 710                         break;
 711                 dprintk("nlmsvc_retry_blocked(%p, when=%ld, done=%d)\n",
 712                         block, block->b_when, block->b_done);
 713                 kref_get(&block->b_count);
 714                 if (block->b_done)
 715                         nlmsvc_unlink_block(block);
 716                 else
 717                         nlmsvc_grant_blocked(block);
 718                 nlmsvc_release_block(block);
 719         }
 720
 721         if ((block = nlm_blocked) && block->b_when != NLM_NEVER)
 722                 return (block->b_when - jiffies);
 723
 724         return MAX_SCHEDULE_TIMEOUT;
 725 }