fs/afs/flock.c

   1 /* AFS file locking support
   2  *
   3  * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
   4  * Written by David Howells (dhowells@redhat.com)
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License
   8  * as published by the Free Software Foundation; either version
   9  * 2 of the License, or (at your option) any later version.
  10  */
  11
  12 #include "internal.h"
  13
  14 #define AFS_LOCK_GRANTED        0
  15 #define AFS_LOCK_PENDING        1
  16
  17 struct workqueue_struct *afs_lock_manager;
  18
  19 static void afs_fl_copy_lock(struct file_lock *new, struct file_lock *fl);
  20 static void afs_fl_release_private(struct file_lock *fl);
  21
  22 static const struct file_lock_operations afs_lock_ops = {
  23         .fl_copy_lock           = afs_fl_copy_lock,
  24         .fl_release_private     = afs_fl_release_private,
  25 };
  26
  27 /*
  28  * if the callback is broken on this vnode, then the lock may now be available
  29  */
  30 void afs_lock_may_be_available(struct afs_vnode *vnode)
  31 {
  32         _enter("{%x:%u}", vnode->fid.vid, vnode->fid.vnode);
  33
  34         queue_delayed_work(afs_lock_manager, &vnode->lock_work, 0);
  35 }
  36
  37 /*
  38  * the lock will time out in 5 minutes unless we extend it, so schedule
  39  * extension in a bit less than that time
  40  */
  41 static void afs_schedule_lock_extension(struct afs_vnode *vnode)
  42 {
  43         queue_delayed_work(afs_lock_manager, &vnode->lock_work,
  44                            AFS_LOCKWAIT * HZ / 2);
  45 }
  46
  47 /*
  48  * grant one or more locks (readlocks are allowed to jump the queue if the
  49  * first lock in the queue is itself a readlock)
  50  * - the caller must hold the vnode lock
  51  */
  52 static void afs_grant_locks(struct afs_vnode *vnode, struct file_lock *fl)
  53 {
  54         struct file_lock *p, *_p;
  55
  56         list_move_tail(&fl->fl_u.afs.link, &vnode->granted_locks);
  57         if (fl->fl_type == F_RDLCK) {
  58                 list_for_each_entry_safe(p, _p, &vnode->pending_locks,
  59                                          fl_u.afs.link) {
  60                         if (p->fl_type == F_RDLCK) {
  61                                 p->fl_u.afs.state = AFS_LOCK_GRANTED;
  62                                 list_move_tail(&p->fl_u.afs.link,
  63                                                &vnode->granted_locks);
  64                                 wake_up(&p->fl_wait);
  65                         }
  66                 }
  67         }
  68 }
  69
  70 /*
  71  * Get a lock on a file
  72  */
  73 static int afs_set_lock(struct afs_vnode *vnode, struct key *key,
  74                         afs_lock_type_t type)
  75 {
  76         struct afs_fs_cursor fc;
  77         int ret;
  78
  79         _enter("%s{%x:%u.%u},%x,%u",
  80                vnode->volume->name,
  81                vnode->fid.vid,
  82                vnode->fid.vnode,
  83                vnode->fid.unique,
  84                key_serial(key), type);
  85
  86         ret = -ERESTARTSYS;
  87         if (afs_begin_vnode_operation(&fc, vnode, key)) {
  88                 while (afs_select_fileserver(&fc)) {
  89                         fc.cb_break = vnode->cb_break + vnode->cb_s_break;
  90                         afs_fs_set_lock(&fc, type);
  91                 }
  92
  93                 afs_check_for_remote_deletion(&fc, fc.vnode);
  94                 afs_vnode_commit_status(&fc, vnode, fc.cb_break);
  95                 ret = afs_end_vnode_operation(&fc);
  96         }
  97
  98         _leave(" = %d", ret);
  99         return ret;
 100 }
 101
 102 /*
 103  * Extend a lock on a file
 104  */
 105 static int afs_extend_lock(struct afs_vnode *vnode, struct key *key)
 106 {
 107         struct afs_fs_cursor fc;
 108         int ret;
 109
 110         _enter("%s{%x:%u.%u},%x",
 111                vnode->volume->name,
 112                vnode->fid.vid,
 113                vnode->fid.vnode,
 114                vnode->fid.unique,
 115                key_serial(key));
 116
 117         ret = -ERESTARTSYS;
 118         if (afs_begin_vnode_operation(&fc, vnode, key)) {
 119                 while (afs_select_current_fileserver(&fc)) {
 120                         fc.cb_break = vnode->cb_break + vnode->cb_s_break;
 121                         afs_fs_extend_lock(&fc);
 122                 }
 123
 124                 afs_check_for_remote_deletion(&fc, fc.vnode);
 125                 afs_vnode_commit_status(&fc, vnode, fc.cb_break);
 126                 ret = afs_end_vnode_operation(&fc);
 127         }
 128
 129         _leave(" = %d", ret);
 130         return ret;
 131 }
 132
 133 /*
 134  * Release a lock on a file
 135  */
 136 static int afs_release_lock(struct afs_vnode *vnode, struct key *key)
 137 {
 138         struct afs_fs_cursor fc;
 139         int ret;
 140
 141         _enter("%s{%x:%u.%u},%x",
 142                vnode->volume->name,
 143                vnode->fid.vid,
 144                vnode->fid.vnode,
 145                vnode->fid.unique,
 146                key_serial(key));
 147
 148         ret = -ERESTARTSYS;
 149         if (afs_begin_vnode_operation(&fc, vnode, key)) {
 150                 while (afs_select_current_fileserver(&fc)) {
 151                         fc.cb_break = vnode->cb_break + vnode->cb_s_break;
 152                         afs_fs_release_lock(&fc);
 153                 }
 154
 155                 afs_check_for_remote_deletion(&fc, fc.vnode);
 156                 afs_vnode_commit_status(&fc, vnode, fc.cb_break);
 157                 ret = afs_end_vnode_operation(&fc);
 158         }
 159
 160         _leave(" = %d", ret);
 161         return ret;
 162 }
 163
 164 /*
 165  * do work for a lock, including:
 166  * - probing for a lock we're waiting on but didn't get immediately
 167  * - extending a lock that's close to timing out
 168  */
 169 void afs_lock_work(struct work_struct *work)
 170 {
 171         struct afs_vnode *vnode =
 172                 container_of(work, struct afs_vnode, lock_work.work);
 173         struct file_lock *fl, *next;
 174         afs_lock_type_t type;
 175         struct key *key;
 176         int ret;
 177
 178         _enter("{%x:%u}", vnode->fid.vid, vnode->fid.vnode);
 179
 180         spin_lock(&vnode->lock);
 181
 182 again:
 183         _debug("wstate %u for %p", vnode->lock_state, vnode);
 184         switch (vnode->lock_state) {
 185         case AFS_VNODE_LOCK_NEED_UNLOCK:
 186                 _debug("unlock");
 187                 vnode->lock_state = AFS_VNODE_LOCK_UNLOCKING;
 188                 spin_unlock(&vnode->lock);
 189
 190                 /* attempt to release the server lock; if it fails, we just
 191                  * wait 5 minutes and it'll expire anyway */
 192                 ret = afs_release_lock(vnode, vnode->lock_key);
 193                 if (ret < 0)
 194                         printk(KERN_WARNING "AFS:"
 195                                " Failed to release lock on {%x:%x} error %d\n",
 196                                vnode->fid.vid, vnode->fid.vnode, ret);
 197
 198                 spin_lock(&vnode->lock);
 199                 key_put(vnode->lock_key);
 200                 vnode->lock_key = NULL;
 201                 vnode->lock_state = AFS_VNODE_LOCK_NONE;
 202
 203                 if (list_empty(&vnode->pending_locks)) {
 204                         spin_unlock(&vnode->lock);
 205                         return;
 206                 }
 207
 208                 /* The new front of the queue now owns the state variables. */
 209                 next = list_entry(vnode->pending_locks.next,
 210                                   struct file_lock, fl_u.afs.link);
 211                 vnode->lock_key = key_get(afs_file_key(next->fl_file));
 212                 vnode->lock_type = (next->fl_type == F_RDLCK) ? AFS_LOCK_READ : AFS_LOCK_WRITE;
 213                 vnode->lock_state = AFS_VNODE_LOCK_WAITING_FOR_CB;
 214                 goto again;
 215
 216         /* If we've already got a lock, then it must be time to extend that
 217          * lock as AFS locks time out after 5 minutes.
 218          */
 219         case AFS_VNODE_LOCK_GRANTED:
 220                 _debug("extend");
 221
 222                 ASSERT(!list_empty(&vnode->granted_locks));
 223
 224                 key = key_get(vnode->lock_key);
 225                 vnode->lock_state = AFS_VNODE_LOCK_EXTENDING;
 226                 spin_unlock(&vnode->lock);
 227
 228                 ret = afs_extend_lock(vnode, key); /* RPC */
 229                 key_put(key);
 230
 231                 if (ret < 0)
 232                         pr_warning("AFS: Failed to extend lock on {%x:%x} error %d\n",
 233                                    vnode->fid.vid, vnode->fid.vnode, ret);
 234
 235                 spin_lock(&vnode->lock);
 236
 237                 if (vnode->lock_state != AFS_VNODE_LOCK_EXTENDING)
 238                         goto again;
 239                 vnode->lock_state = AFS_VNODE_LOCK_GRANTED;
 240
 241                 if (ret == 0)
 242                         afs_schedule_lock_extension(vnode);
 243                 else
 244                         queue_delayed_work(afs_lock_manager, &vnode->lock_work,
 245                                            HZ * 10);
 246                 spin_unlock(&vnode->lock);
 247                 _leave(" [ext]");
 248                 return;
 249
 250                 /* If we don't have a granted lock, then we must've been called
 251                  * back by the server, and so if might be possible to get a
 252                  * lock we're currently waiting for.
 253                  */
 254         case AFS_VNODE_LOCK_WAITING_FOR_CB:
 255                 _debug("get");
 256
 257                 key = key_get(vnode->lock_key);
 258                 type = vnode->lock_type;
 259                 vnode->lock_state = AFS_VNODE_LOCK_SETTING;
 260                 spin_unlock(&vnode->lock);
 261
 262                 ret = afs_set_lock(vnode, key, type); /* RPC */
 263                 key_put(key);
 264
 265                 spin_lock(&vnode->lock);
 266                 switch (ret) {
 267                 case -EWOULDBLOCK:
 268                         _debug("blocked");
 269                         break;
 270                 case 0:
 271                         _debug("acquired");
 272                         vnode->lock_state = AFS_VNODE_LOCK_GRANTED;
 273                         /* Fall through */
 274                 default:
 275                         /* Pass the lock or the error onto the first locker in
 276                          * the list - if they're looking for this type of lock.
 277                          * If they're not, we assume that whoever asked for it
 278                          * took a signal.
 279                          */
 280                         if (list_empty(&vnode->pending_locks)) {
 281                                 _debug("withdrawn");
 282                                 vnode->lock_state = AFS_VNODE_LOCK_NEED_UNLOCK;
 283                                 goto again;
 284                         }
 285
 286                         fl = list_entry(vnode->pending_locks.next,
 287                                         struct file_lock, fl_u.afs.link);
 288                         type = (fl->fl_type == F_RDLCK) ? AFS_LOCK_READ : AFS_LOCK_WRITE;
 289                         if (vnode->lock_type != type) {
 290                                 _debug("changed");
 291                                 vnode->lock_state = AFS_VNODE_LOCK_NEED_UNLOCK;
 292                                 goto again;
 293                         }
 294
 295                         fl->fl_u.afs.state = ret;
 296                         if (ret == 0)
 297                                 afs_grant_locks(vnode, fl);
 298                         else
 299                                 list_del_init(&fl->fl_u.afs.link);
 300                         wake_up(&fl->fl_wait);
 301                         spin_unlock(&vnode->lock);
 302                         _leave(" [granted]");
 303                         return;
 304                 }
 305
 306         default:
 307                 /* Looks like a lock request was withdrawn. */
 308                 spin_unlock(&vnode->lock);
 309                 _leave(" [no]");
 310                 return;
 311         }
 312 }
 313
 314 /*
 315  * pass responsibility for the unlocking of a vnode on the server to the
 316  * manager thread, lest a pending signal in the calling thread interrupt
 317  * AF_RXRPC
 318  * - the caller must hold the vnode lock
 319  */
 320 static void afs_defer_unlock(struct afs_vnode *vnode)
 321 {
 322         _enter("");
 323
 324         if (vnode->lock_state == AFS_VNODE_LOCK_GRANTED ||
 325             vnode->lock_state == AFS_VNODE_LOCK_EXTENDING) {
 326                 cancel_delayed_work(&vnode->lock_work);
 327
 328                 vnode->lock_state = AFS_VNODE_LOCK_NEED_UNLOCK;
 329                 afs_lock_may_be_available(vnode);
 330         }
 331 }
 332
 333 /*
 334  * Check that our view of the file metadata is up to date and check to see
 335  * whether we think that we have a locking permit.
 336  */
 337 static int afs_do_setlk_check(struct afs_vnode *vnode, struct key *key,
 338                               afs_lock_type_t type, bool can_sleep)
 339 {
 340         afs_access_t access;
 341         int ret;
 342
 343         /* Make sure we've got a callback on this file and that our view of the
 344          * data version is up to date.
 345          */
 346         ret = afs_validate(vnode, key);
 347         if (ret < 0)
 348                 return ret;
 349
 350         /* Check the permission set to see if we're actually going to be
 351          * allowed to get a lock on this file.
 352          */
 353         ret = afs_check_permit(vnode, key, &access);
 354         if (ret < 0)
 355                 return ret;
 356
 357         /* At a rough estimation, you need LOCK, WRITE or INSERT perm to
 358          * read-lock a file and WRITE or INSERT perm to write-lock a file.
 359          *
 360          * We can't rely on the server to do this for us since if we want to
 361          * share a read lock that we already have, we won't go the server.
 362          */
 363         if (type == AFS_LOCK_READ) {
 364                 if (!(access & (AFS_ACE_INSERT | AFS_ACE_WRITE | AFS_ACE_LOCK)))
 365                         return -EACCES;
 366                 if (vnode->status.lock_count == -1 && !can_sleep)
 367                         return -EAGAIN; /* Write locked */
 368         } else {
 369                 if (!(access & (AFS_ACE_INSERT | AFS_ACE_WRITE)))
 370                         return -EACCES;
 371                 if (vnode->status.lock_count != 0 && !can_sleep)
 372                         return -EAGAIN; /* Locked */
 373         }
 374
 375         return 0;
 376 }
 377
 378 /*
 379  * Remove the front runner from the pending queue.
 380  * - The caller must hold vnode->lock.
 381  */
 382 static void afs_dequeue_lock(struct afs_vnode *vnode, struct file_lock *fl)
 383 {
 384         struct file_lock *next;
 385
 386         _enter("");
 387
 388         /* ->lock_type, ->lock_key and ->lock_state only belong to this
 389          * file_lock if we're at the front of the pending queue or if we have
 390          * the lock granted or if the lock_state is NEED_UNLOCK or UNLOCKING.
 391          */
 392         if (vnode->granted_locks.next == &fl->fl_u.afs.link &&
 393             vnode->granted_locks.prev == &fl->fl_u.afs.link) {
 394                 list_del_init(&fl->fl_u.afs.link);
 395                 afs_defer_unlock(vnode);
 396                 return;
 397         }
 398
 399         if (!list_empty(&vnode->granted_locks) ||
 400             vnode->pending_locks.next != &fl->fl_u.afs.link) {
 401                 list_del_init(&fl->fl_u.afs.link);
 402                 return;
 403         }
 404
 405         list_del_init(&fl->fl_u.afs.link);
 406         key_put(vnode->lock_key);
 407         vnode->lock_key = NULL;
 408         vnode->lock_state = AFS_VNODE_LOCK_NONE;
 409
 410         if (list_empty(&vnode->pending_locks))
 411                 return;
 412
 413         /* The new front of the queue now owns the state variables. */
 414         next = list_entry(vnode->pending_locks.next,
 415                           struct file_lock, fl_u.afs.link);
 416         vnode->lock_key = key_get(afs_file_key(next->fl_file));
 417         vnode->lock_type = (next->fl_type == F_RDLCK) ? AFS_LOCK_READ : AFS_LOCK_WRITE;
 418         vnode->lock_state = AFS_VNODE_LOCK_WAITING_FOR_CB;
 419         afs_lock_may_be_available(vnode);
 420 }
 421
 422 /*
 423  * request a lock on a file on the server
 424  */
 425 static int afs_do_setlk(struct file *file, struct file_lock *fl)
 426 {
 427         struct inode *inode = locks_inode(file);
 428         struct afs_vnode *vnode = AFS_FS_I(inode);
 429         afs_lock_type_t type;
 430         struct key *key = afs_file_key(file);
 431         int ret;
 432
 433         _enter("{%x:%u},%u", vnode->fid.vid, vnode->fid.vnode, fl->fl_type);
 434
 435         fl->fl_ops = &afs_lock_ops;
 436         INIT_LIST_HEAD(&fl->fl_u.afs.link);
 437         fl->fl_u.afs.state = AFS_LOCK_PENDING;
 438
 439         type = (fl->fl_type == F_RDLCK) ? AFS_LOCK_READ : AFS_LOCK_WRITE;
 440
 441         ret = afs_do_setlk_check(vnode, key, type, fl->fl_flags & FL_SLEEP);
 442         if (ret < 0)
 443                 return ret;
 444
 445         spin_lock(&vnode->lock);
 446
 447         /* If we've already got a readlock on the server then we instantly
 448          * grant another readlock, irrespective of whether there are any
 449          * pending writelocks.
 450          */
 451         if (type == AFS_LOCK_READ &&
 452             vnode->lock_state == AFS_VNODE_LOCK_GRANTED &&
 453             vnode->lock_type == AFS_LOCK_READ) {
 454                 _debug("instant readlock");
 455                 ASSERT(!list_empty(&vnode->granted_locks));
 456                 goto share_existing_lock;
 457         }
 458
 459         list_add_tail(&fl->fl_u.afs.link, &vnode->pending_locks);
 460
 461         if (vnode->lock_state != AFS_VNODE_LOCK_NONE)
 462                 goto need_to_wait;
 463
 464         /* We don't have a lock on this vnode and we aren't currently waiting
 465          * for one either, so ask the server for a lock.
 466          *
 467          * Note that we need to be careful if we get interrupted by a signal
 468          * after dispatching the request as we may still get the lock, even
 469          * though we don't wait for the reply (it's not too bad a problem - the
 470          * lock will expire in 10 mins anyway).
 471          */
 472         _debug("not locked");
 473         vnode->lock_key = key_get(key);
 474         vnode->lock_type = type;
 475         vnode->lock_state = AFS_VNODE_LOCK_SETTING;
 476         spin_unlock(&vnode->lock);
 477
 478         ret = afs_set_lock(vnode, key, type); /* RPC */
 479
 480         spin_lock(&vnode->lock);
 481         switch (ret) {
 482         default:
 483                 goto abort_attempt;
 484
 485         case -EWOULDBLOCK:
 486                 /* The server doesn't have a lock-waiting queue, so the client
 487                  * will have to retry.  The server will break the outstanding
 488                  * callbacks on a file when a lock is released.
 489                  */
 490                 _debug("would block");
 491                 ASSERT(list_empty(&vnode->granted_locks));
 492                 ASSERTCMP(vnode->pending_locks.next, ==, &fl->fl_u.afs.link);
 493                 vnode->lock_state = AFS_VNODE_LOCK_WAITING_FOR_CB;
 494                 goto need_to_wait;
 495
 496         case 0:
 497                 _debug("acquired");
 498                 break;
 499         }
 500
 501         /* we've acquired a server lock, but it needs to be renewed after 5
 502          * mins */
 503         vnode->lock_state = AFS_VNODE_LOCK_GRANTED;
 504         afs_schedule_lock_extension(vnode);
 505
 506 share_existing_lock:
 507         /* the lock has been granted as far as we're concerned... */
 508         fl->fl_u.afs.state = AFS_LOCK_GRANTED;
 509         list_move_tail(&fl->fl_u.afs.link, &vnode->granted_locks);
 510
 511 given_lock:
 512         /* ... but we do still need to get the VFS's blessing */
 513         spin_unlock(&vnode->lock);
 514
 515         ret = posix_lock_file(file, fl, NULL);
 516         if (ret < 0)
 517                 goto vfs_rejected_lock;
 518
 519         /* Again, make sure we've got a callback on this file and, again, make
 520          * sure that our view of the data version is up to date (we ignore
 521          * errors incurred here and deal with the consequences elsewhere).
 522          */
 523         afs_validate(vnode, key);
 524         _leave(" = 0");
 525         return 0;
 526
 527 need_to_wait:
 528         /* We're going to have to wait.  Either this client doesn't have a lock
 529          * on the server yet and we need to wait for a callback to occur, or
 530          * the client does have a lock on the server, but it belongs to some
 531          * other process(es) and is incompatible with the lock we want.
 532          */
 533         ret = -EAGAIN;
 534         if (fl->fl_flags & FL_SLEEP) {
 535                 spin_unlock(&vnode->lock);
 536
 537                 _debug("sleep");
 538                 ret = wait_event_interruptible(fl->fl_wait,
 539                                                fl->fl_u.afs.state != AFS_LOCK_PENDING);
 540
 541                 spin_lock(&vnode->lock);
 542         }
 543
 544         if (fl->fl_u.afs.state == AFS_LOCK_GRANTED)
 545                 goto given_lock;
 546         if (fl->fl_u.afs.state < 0)
 547                 ret = fl->fl_u.afs.state;
 548
 549 abort_attempt:
 550         /* we aren't going to get the lock, either because we're unwilling to
 551          * wait, or because some signal happened */
 552         _debug("abort");
 553         afs_dequeue_lock(vnode, fl);
 554
 555 error_unlock:
 556         spin_unlock(&vnode->lock);
 557         _leave(" = %d", ret);
 558         return ret;
 559
 560 vfs_rejected_lock:
 561         /* The VFS rejected the lock we just obtained, so we have to discard
 562          * what we just got.  We defer this to the lock manager work item to
 563          * deal with.
 564          */
 565         _debug("vfs refused %d", ret);
 566         spin_lock(&vnode->lock);
 567         list_del_init(&fl->fl_u.afs.link);
 568         if (list_empty(&vnode->granted_locks))
 569                 afs_defer_unlock(vnode);
 570         goto error_unlock;
 571 }
 572
 573 /*
 574  * unlock on a file on the server
 575  */
 576 static int afs_do_unlk(struct file *file, struct file_lock *fl)
 577 {
 578         struct afs_vnode *vnode = AFS_FS_I(locks_inode(file));
 579         int ret;
 580
 581         _enter("{%x:%u},%u", vnode->fid.vid, vnode->fid.vnode, fl->fl_type);
 582
 583         /* Flush all pending writes before doing anything with locks. */
 584         vfs_fsync(file, 0);
 585
 586         ret = posix_lock_file(file, fl, NULL);
 587         _leave(" = %d [%u]", ret, vnode->lock_state);
 588         return ret;
 589 }
 590
 591 /*
 592  * return information about a lock we currently hold, if indeed we hold one
 593  */
 594 static int afs_do_getlk(struct file *file, struct file_lock *fl)
 595 {
 596         struct afs_vnode *vnode = AFS_FS_I(locks_inode(file));
 597         struct key *key = afs_file_key(file);
 598         int ret, lock_count;
 599
 600         _enter("");
 601
 602         fl->fl_type = F_UNLCK;
 603
 604         /* check local lock records first */
 605         posix_test_lock(file, fl);
 606         if (fl->fl_type == F_UNLCK) {
 607                 /* no local locks; consult the server */
 608                 ret = afs_fetch_status(vnode, key);
 609                 if (ret < 0)
 610                         goto error;
 611
 612                 lock_count = READ_ONCE(vnode->status.lock_count);
 613                 if (lock_count != 0) {
 614                         if (lock_count > 0)
 615                                 fl->fl_type = F_RDLCK;
 616                         else
 617                                 fl->fl_type = F_WRLCK;
 618                         fl->fl_start = 0;
 619                         fl->fl_end = OFFSET_MAX;
 620                         fl->fl_pid = 0;
 621                 }
 622         }
 623
 624         ret = 0;
 625 error:
 626         _leave(" = %d [%hd]", ret, fl->fl_type);
 627         return ret;
 628 }
 629
 630 /*
 631  * manage POSIX locks on a file
 632  */
 633 int afs_lock(struct file *file, int cmd, struct file_lock *fl)
 634 {
 635         struct afs_vnode *vnode = AFS_FS_I(locks_inode(file));
 636
 637         _enter("{%x:%u},%d,{t=%x,fl=%x,r=%Ld:%Ld}",
 638                vnode->fid.vid, vnode->fid.vnode, cmd,
 639                fl->fl_type, fl->fl_flags,
 640                (long long) fl->fl_start, (long long) fl->fl_end);
 641
 642         /* AFS doesn't support mandatory locks */
 643         if (__mandatory_lock(&vnode->vfs_inode) && fl->fl_type != F_UNLCK)
 644                 return -ENOLCK;
 645
 646         if (IS_GETLK(cmd))
 647                 return afs_do_getlk(file, fl);
 648         if (fl->fl_type == F_UNLCK)
 649                 return afs_do_unlk(file, fl);
 650         return afs_do_setlk(file, fl);
 651 }
 652
 653 /*
 654  * manage FLOCK locks on a file
 655  */
 656 int afs_flock(struct file *file, int cmd, struct file_lock *fl)
 657 {
 658         struct afs_vnode *vnode = AFS_FS_I(locks_inode(file));
 659
 660         _enter("{%x:%u},%d,{t=%x,fl=%x}",
 661                vnode->fid.vid, vnode->fid.vnode, cmd,
 662                fl->fl_type, fl->fl_flags);
 663
 664         /*
 665          * No BSD flocks over NFS allowed.
 666          * Note: we could try to fake a POSIX lock request here by
 667          * using ((u32) filp | 0x80000000) or some such as the pid.
 668          * Not sure whether that would be unique, though, or whether
 669          * that would break in other places.
 670          */
 671         if (!(fl->fl_flags & FL_FLOCK))
 672                 return -ENOLCK;
 673
 674         /* we're simulating flock() locks using posix locks on the server */
 675         if (fl->fl_type == F_UNLCK)
 676                 return afs_do_unlk(file, fl);
 677         return afs_do_setlk(file, fl);
 678 }
 679
 680 /*
 681  * the POSIX lock management core VFS code copies the lock record and adds the
 682  * copy into its own list, so we need to add that copy to the vnode's lock
 683  * queue in the same place as the original (which will be deleted shortly
 684  * after)
 685  */
 686 static void afs_fl_copy_lock(struct file_lock *new, struct file_lock *fl)
 687 {
 688         struct afs_vnode *vnode = AFS_FS_I(locks_inode(fl->fl_file));
 689
 690         _enter("");
 691
 692         spin_lock(&vnode->lock);
 693         list_add(&new->fl_u.afs.link, &fl->fl_u.afs.link);
 694         spin_unlock(&vnode->lock);
 695 }
 696
 697 /*
 698  * need to remove this lock from the vnode queue when it's removed from the
 699  * VFS's list
 700  */
 701 static void afs_fl_release_private(struct file_lock *fl)
 702 {
 703         struct afs_vnode *vnode = AFS_FS_I(locks_inode(fl->fl_file));
 704
 705         _enter("");
 706
 707         spin_lock(&vnode->lock);
 708         afs_dequeue_lock(vnode, fl);
 709         _debug("state %u for %p", vnode->lock_state, vnode);
 710         spin_unlock(&vnode->lock);
 711 }