1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* AFS file locking support 3 * 4 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved. 5 * Written by David Howells (dhowells@redhat.com) 6 */ 7 8 #include "internal.h" 9 10 #define AFS_LOCK_GRANTED 0 11 #define AFS_LOCK_PENDING 1 12 #define AFS_LOCK_YOUR_TRY 2 13 14 struct workqueue_struct *afs_lock_manager; 15 16 static void afs_next_locker(struct afs_vnode *vnode, int error); 17 static void afs_fl_copy_lock(struct file_lock *new, struct file_lock *fl); 18 static void afs_fl_release_private(struct file_lock *fl); 19 20 static const struct file_lock_operations afs_lock_ops = { 21 .fl_copy_lock = afs_fl_copy_lock, 22 .fl_release_private = afs_fl_release_private, 23 }; 24 afs_set_lock_state(struct afs_vnode * vnode,enum afs_lock_state state)25 static inline void afs_set_lock_state(struct afs_vnode *vnode, enum afs_lock_state state) 26 { 27 _debug("STATE %u -> %u", vnode->lock_state, state); 28 vnode->lock_state = state; 29 } 30 31 static atomic_t afs_file_lock_debug_id; 32 33 /* 34 * if the callback is broken on this vnode, then the lock may now be available 35 */ afs_lock_may_be_available(struct afs_vnode * vnode)36 void afs_lock_may_be_available(struct afs_vnode *vnode) 37 { 38 _enter("{%llx:%llu}", vnode->fid.vid, vnode->fid.vnode); 39 40 spin_lock(&vnode->lock); 41 if (vnode->lock_state == AFS_VNODE_LOCK_WAITING_FOR_CB) 42 afs_next_locker(vnode, 0); 43 trace_afs_flock_ev(vnode, NULL, afs_flock_callback_break, 0); 44 spin_unlock(&vnode->lock); 45 } 46 47 /* 48 * the lock will time out in 5 minutes unless we extend it, so schedule 49 * extension in a bit less than that time 50 */ afs_schedule_lock_extension(struct afs_vnode * vnode)51 static void afs_schedule_lock_extension(struct afs_vnode *vnode) 52 { 53 ktime_t expires_at, now, duration; 54 u64 duration_j; 55 56 expires_at = ktime_add_ms(vnode->locked_at, AFS_LOCKWAIT * 1000 / 2); 57 now = ktime_get_real(); 58 duration = ktime_sub(expires_at, now); 59 if (duration <= 0) 60 duration_j = 0; 61 else 62 duration_j = nsecs_to_jiffies(ktime_to_ns(duration)); 63 64 queue_delayed_work(afs_lock_manager, &vnode->lock_work, duration_j); 65 } 66 67 /* 68 * In the case of successful completion of a lock operation, record the time 69 * the reply appeared and start the lock extension timer. 70 */ afs_lock_op_done(struct afs_call * call)71 void afs_lock_op_done(struct afs_call *call) 72 { 73 struct afs_operation *op = call->op; 74 struct afs_vnode *vnode = op->file[0].vnode; 75 76 if (call->error == 0) { 77 spin_lock(&vnode->lock); 78 trace_afs_flock_ev(vnode, NULL, afs_flock_timestamp, 0); 79 vnode->locked_at = call->issue_time; 80 afs_schedule_lock_extension(vnode); 81 spin_unlock(&vnode->lock); 82 } 83 } 84 85 /* 86 * grant one or more locks (readlocks are allowed to jump the queue if the 87 * first lock in the queue is itself a readlock) 88 * - the caller must hold the vnode lock 89 */ afs_grant_locks(struct afs_vnode * vnode)90 static void afs_grant_locks(struct afs_vnode *vnode) 91 { 92 struct file_lock *p, *_p; 93 bool exclusive = (vnode->lock_type == AFS_LOCK_WRITE); 94 95 list_for_each_entry_safe(p, _p, &vnode->pending_locks, fl_u.afs.link) { 96 if (!exclusive && lock_is_write(p)) 97 continue; 98 99 list_move_tail(&p->fl_u.afs.link, &vnode->granted_locks); 100 p->fl_u.afs.state = AFS_LOCK_GRANTED; 101 trace_afs_flock_op(vnode, p, afs_flock_op_grant); 102 locks_wake_up(p); 103 } 104 } 105 106 /* 107 * If an error is specified, reject every pending lock that matches the 108 * authentication and type of the lock we failed to get. If there are any 109 * remaining lockers, try to wake up one of them to have a go. 110 */ afs_next_locker(struct afs_vnode * vnode,int error)111 static void afs_next_locker(struct afs_vnode *vnode, int error) 112 { 113 struct file_lock *p, *_p, *next = NULL; 114 struct key *key = vnode->lock_key; 115 unsigned int type = F_RDLCK; 116 117 _enter(""); 118 119 if (vnode->lock_type == AFS_LOCK_WRITE) 120 type = F_WRLCK; 121 122 list_for_each_entry_safe(p, _p, &vnode->pending_locks, fl_u.afs.link) { 123 if (error && 124 p->c.flc_type == type && 125 afs_file_key(p->c.flc_file) == key) { 126 list_del_init(&p->fl_u.afs.link); 127 p->fl_u.afs.state = error; 128 locks_wake_up(p); 129 } 130 131 /* Select the next locker to hand off to. */ 132 if (next && (lock_is_write(next) || lock_is_read(p))) 133 continue; 134 next = p; 135 } 136 137 vnode->lock_key = NULL; 138 key_put(key); 139 140 if (next) { 141 afs_set_lock_state(vnode, AFS_VNODE_LOCK_SETTING); 142 next->fl_u.afs.state = AFS_LOCK_YOUR_TRY; 143 trace_afs_flock_op(vnode, next, afs_flock_op_wake); 144 locks_wake_up(next); 145 } else { 146 afs_set_lock_state(vnode, AFS_VNODE_LOCK_NONE); 147 trace_afs_flock_ev(vnode, NULL, afs_flock_no_lockers, 0); 148 } 149 150 _leave(""); 151 } 152 153 /* 154 * Kill off all waiters in the the pending lock queue due to the vnode being 155 * deleted. 156 */ afs_kill_lockers_enoent(struct afs_vnode * vnode)157 static void afs_kill_lockers_enoent(struct afs_vnode *vnode) 158 { 159 struct file_lock *p; 160 161 afs_set_lock_state(vnode, AFS_VNODE_LOCK_DELETED); 162 163 while (!list_empty(&vnode->pending_locks)) { 164 p = list_entry(vnode->pending_locks.next, 165 struct file_lock, fl_u.afs.link); 166 list_del_init(&p->fl_u.afs.link); 167 p->fl_u.afs.state = -ENOENT; 168 locks_wake_up(p); 169 } 170 171 key_put(vnode->lock_key); 172 vnode->lock_key = NULL; 173 } 174 afs_lock_success(struct afs_operation * op)175 static void afs_lock_success(struct afs_operation *op) 176 { 177 _enter("op=%08x", op->debug_id); 178 afs_vnode_commit_status(op, &op->file[0]); 179 } 180 181 static const struct afs_operation_ops afs_set_lock_operation = { 182 .issue_afs_rpc = afs_fs_set_lock, 183 .issue_yfs_rpc = yfs_fs_set_lock, 184 .success = afs_lock_success, 185 .aborted = afs_check_for_remote_deletion, 186 }; 187 188 /* 189 * Get a lock on a file 190 */ afs_set_lock(struct afs_vnode * vnode,struct key * key,afs_lock_type_t type)191 static int afs_set_lock(struct afs_vnode *vnode, struct key *key, 192 afs_lock_type_t type) 193 { 194 struct afs_operation *op; 195 196 _enter("%s{%llx:%llu.%u},%x,%u", 197 vnode->volume->name, 198 vnode->fid.vid, 199 vnode->fid.vnode, 200 vnode->fid.unique, 201 key_serial(key), type); 202 203 op = afs_alloc_operation(key, vnode->volume); 204 if (IS_ERR(op)) 205 return PTR_ERR(op); 206 207 afs_op_set_vnode(op, 0, vnode); 208 209 op->lock.type = type; 210 op->ops = &afs_set_lock_operation; 211 return afs_do_sync_operation(op); 212 } 213 214 static const struct afs_operation_ops afs_extend_lock_operation = { 215 .issue_afs_rpc = afs_fs_extend_lock, 216 .issue_yfs_rpc = yfs_fs_extend_lock, 217 .success = afs_lock_success, 218 }; 219 220 /* 221 * Extend a lock on a file 222 */ afs_extend_lock(struct afs_vnode * vnode,struct key * key)223 static int afs_extend_lock(struct afs_vnode *vnode, struct key *key) 224 { 225 struct afs_operation *op; 226 227 _enter("%s{%llx:%llu.%u},%x", 228 vnode->volume->name, 229 vnode->fid.vid, 230 vnode->fid.vnode, 231 vnode->fid.unique, 232 key_serial(key)); 233 234 op = afs_alloc_operation(key, vnode->volume); 235 if (IS_ERR(op)) 236 return PTR_ERR(op); 237 238 afs_op_set_vnode(op, 0, vnode); 239 240 op->flags |= AFS_OPERATION_UNINTR; 241 op->ops = &afs_extend_lock_operation; 242 return afs_do_sync_operation(op); 243 } 244 245 static const struct afs_operation_ops afs_release_lock_operation = { 246 .issue_afs_rpc = afs_fs_release_lock, 247 .issue_yfs_rpc = yfs_fs_release_lock, 248 .success = afs_lock_success, 249 }; 250 251 /* 252 * Release a lock on a file 253 */ afs_release_lock(struct afs_vnode * vnode,struct key * key)254 static int afs_release_lock(struct afs_vnode *vnode, struct key *key) 255 { 256 struct afs_operation *op; 257 258 _enter("%s{%llx:%llu.%u},%x", 259 vnode->volume->name, 260 vnode->fid.vid, 261 vnode->fid.vnode, 262 vnode->fid.unique, 263 key_serial(key)); 264 265 op = afs_alloc_operation(key, vnode->volume); 266 if (IS_ERR(op)) 267 return PTR_ERR(op); 268 269 afs_op_set_vnode(op, 0, vnode); 270 271 op->flags |= AFS_OPERATION_UNINTR; 272 op->ops = &afs_release_lock_operation; 273 return afs_do_sync_operation(op); 274 } 275 276 /* 277 * do work for a lock, including: 278 * - probing for a lock we're waiting on but didn't get immediately 279 * - extending a lock that's close to timing out 280 */ afs_lock_work(struct work_struct * work)281 void afs_lock_work(struct work_struct *work) 282 { 283 struct afs_vnode *vnode = 284 container_of(work, struct afs_vnode, lock_work.work); 285 struct key *key; 286 int ret; 287 288 _enter("{%llx:%llu}", vnode->fid.vid, vnode->fid.vnode); 289 290 spin_lock(&vnode->lock); 291 292 again: 293 _debug("wstate %u for %p", vnode->lock_state, vnode); 294 switch (vnode->lock_state) { 295 case AFS_VNODE_LOCK_NEED_UNLOCK: 296 afs_set_lock_state(vnode, AFS_VNODE_LOCK_UNLOCKING); 297 trace_afs_flock_ev(vnode, NULL, afs_flock_work_unlocking, 0); 298 spin_unlock(&vnode->lock); 299 300 /* attempt to release the server lock; if it fails, we just 301 * wait 5 minutes and it'll expire anyway */ 302 ret = afs_release_lock(vnode, vnode->lock_key); 303 if (ret < 0 && vnode->lock_state != AFS_VNODE_LOCK_DELETED) { 304 trace_afs_flock_ev(vnode, NULL, afs_flock_release_fail, 305 ret); 306 printk(KERN_WARNING "AFS:" 307 " Failed to release lock on {%llx:%llx} error %d\n", 308 vnode->fid.vid, vnode->fid.vnode, ret); 309 } 310 311 spin_lock(&vnode->lock); 312 if (ret == -ENOENT) 313 afs_kill_lockers_enoent(vnode); 314 else 315 afs_next_locker(vnode, 0); 316 spin_unlock(&vnode->lock); 317 return; 318 319 /* If we've already got a lock, then it must be time to extend that 320 * lock as AFS locks time out after 5 minutes. 321 */ 322 case AFS_VNODE_LOCK_GRANTED: 323 _debug("extend"); 324 325 ASSERT(!list_empty(&vnode->granted_locks)); 326 327 key = key_get(vnode->lock_key); 328 afs_set_lock_state(vnode, AFS_VNODE_LOCK_EXTENDING); 329 trace_afs_flock_ev(vnode, NULL, afs_flock_work_extending, 0); 330 spin_unlock(&vnode->lock); 331 332 ret = afs_extend_lock(vnode, key); /* RPC */ 333 key_put(key); 334 335 if (ret < 0) { 336 trace_afs_flock_ev(vnode, NULL, afs_flock_extend_fail, 337 ret); 338 pr_warn("AFS: Failed to extend lock on {%llx:%llx} error %d\n", 339 vnode->fid.vid, vnode->fid.vnode, ret); 340 } 341 342 spin_lock(&vnode->lock); 343 344 if (ret == -ENOENT) { 345 afs_kill_lockers_enoent(vnode); 346 spin_unlock(&vnode->lock); 347 return; 348 } 349 350 if (vnode->lock_state != AFS_VNODE_LOCK_EXTENDING) 351 goto again; 352 afs_set_lock_state(vnode, AFS_VNODE_LOCK_GRANTED); 353 354 if (ret != 0) 355 queue_delayed_work(afs_lock_manager, &vnode->lock_work, 356 HZ * 10); 357 spin_unlock(&vnode->lock); 358 _leave(" [ext]"); 359 return; 360 361 /* If we're waiting for a callback to indicate lock release, we can't 362 * actually rely on this, so need to recheck at regular intervals. The 363 * problem is that the server might not notify us if the lock just 364 * expires (say because a client died) rather than being explicitly 365 * released. 366 */ 367 case AFS_VNODE_LOCK_WAITING_FOR_CB: 368 _debug("retry"); 369 afs_next_locker(vnode, 0); 370 spin_unlock(&vnode->lock); 371 return; 372 373 case AFS_VNODE_LOCK_DELETED: 374 afs_kill_lockers_enoent(vnode); 375 spin_unlock(&vnode->lock); 376 return; 377 378 default: 379 /* Looks like a lock request was withdrawn. */ 380 spin_unlock(&vnode->lock); 381 _leave(" [no]"); 382 return; 383 } 384 } 385 386 /* 387 * pass responsibility for the unlocking of a vnode on the server to the 388 * manager thread, lest a pending signal in the calling thread interrupt 389 * AF_RXRPC 390 * - the caller must hold the vnode lock 391 */ afs_defer_unlock(struct afs_vnode * vnode)392 static void afs_defer_unlock(struct afs_vnode *vnode) 393 { 394 _enter("%u", vnode->lock_state); 395 396 if (list_empty(&vnode->granted_locks) && 397 (vnode->lock_state == AFS_VNODE_LOCK_GRANTED || 398 vnode->lock_state == AFS_VNODE_LOCK_EXTENDING)) { 399 cancel_delayed_work(&vnode->lock_work); 400 401 afs_set_lock_state(vnode, AFS_VNODE_LOCK_NEED_UNLOCK); 402 trace_afs_flock_ev(vnode, NULL, afs_flock_defer_unlock, 0); 403 queue_delayed_work(afs_lock_manager, &vnode->lock_work, 0); 404 } 405 } 406 407 /* 408 * Check that our view of the file metadata is up to date and check to see 409 * whether we think that we have a locking permit. 410 */ afs_do_setlk_check(struct afs_vnode * vnode,struct key * key,enum afs_flock_mode mode,afs_lock_type_t type)411 static int afs_do_setlk_check(struct afs_vnode *vnode, struct key *key, 412 enum afs_flock_mode mode, afs_lock_type_t type) 413 { 414 afs_access_t access; 415 int ret; 416 417 /* Make sure we've got a callback on this file and that our view of the 418 * data version is up to date. 419 */ 420 ret = afs_validate(vnode, key); 421 if (ret < 0) 422 return ret; 423 424 /* Check the permission set to see if we're actually going to be 425 * allowed to get a lock on this file. 426 */ 427 ret = afs_check_permit(vnode, key, &access); 428 if (ret < 0) 429 return ret; 430 431 /* At a rough estimation, you need LOCK, WRITE or INSERT perm to 432 * read-lock a file and WRITE or INSERT perm to write-lock a file. 433 * 434 * We can't rely on the server to do this for us since if we want to 435 * share a read lock that we already have, we won't go the server. 436 */ 437 if (type == AFS_LOCK_READ) { 438 if (!(access & (AFS_ACE_INSERT | AFS_ACE_WRITE | AFS_ACE_LOCK))) 439 return -EACCES; 440 } else { 441 if (!(access & (AFS_ACE_INSERT | AFS_ACE_WRITE))) 442 return -EACCES; 443 } 444 445 return 0; 446 } 447 448 /* 449 * request a lock on a file on the server 450 */ afs_do_setlk(struct file * file,struct file_lock * fl)451 static int afs_do_setlk(struct file *file, struct file_lock *fl) 452 { 453 struct inode *inode = file_inode(file); 454 struct afs_vnode *vnode = AFS_FS_I(inode); 455 enum afs_flock_mode mode = AFS_FS_S(inode->i_sb)->flock_mode; 456 afs_lock_type_t type; 457 struct key *key = afs_file_key(file); 458 bool partial, no_server_lock = false; 459 int ret; 460 461 if (mode == afs_flock_mode_unset) 462 mode = afs_flock_mode_openafs; 463 464 _enter("{%llx:%llu},%llu-%llu,%u,%u", 465 vnode->fid.vid, vnode->fid.vnode, 466 fl->fl_start, fl->fl_end, fl->c.flc_type, mode); 467 468 fl->fl_ops = &afs_lock_ops; 469 INIT_LIST_HEAD(&fl->fl_u.afs.link); 470 fl->fl_u.afs.state = AFS_LOCK_PENDING; 471 472 partial = (fl->fl_start != 0 || fl->fl_end != OFFSET_MAX); 473 type = lock_is_read(fl) ? AFS_LOCK_READ : AFS_LOCK_WRITE; 474 if (mode == afs_flock_mode_write && partial) 475 type = AFS_LOCK_WRITE; 476 477 ret = afs_do_setlk_check(vnode, key, mode, type); 478 if (ret < 0) 479 return ret; 480 481 trace_afs_flock_op(vnode, fl, afs_flock_op_set_lock); 482 483 /* AFS3 protocol only supports full-file locks and doesn't provide any 484 * method of upgrade/downgrade, so we need to emulate for partial-file 485 * locks. 486 * 487 * The OpenAFS client only gets a server lock for a full-file lock and 488 * keeps partial-file locks local. Allow this behaviour to be emulated 489 * (as the default). 490 */ 491 if (mode == afs_flock_mode_local || 492 (partial && mode == afs_flock_mode_openafs)) { 493 no_server_lock = true; 494 goto skip_server_lock; 495 } 496 497 spin_lock(&vnode->lock); 498 list_add_tail(&fl->fl_u.afs.link, &vnode->pending_locks); 499 500 ret = -ENOENT; 501 if (vnode->lock_state == AFS_VNODE_LOCK_DELETED) 502 goto error_unlock; 503 504 /* If we've already got a lock on the server then try to move to having 505 * the VFS grant the requested lock. Note that this means that other 506 * clients may get starved out. 507 */ 508 _debug("try %u", vnode->lock_state); 509 if (vnode->lock_state == AFS_VNODE_LOCK_GRANTED) { 510 if (type == AFS_LOCK_READ) { 511 _debug("instant readlock"); 512 list_move_tail(&fl->fl_u.afs.link, &vnode->granted_locks); 513 fl->fl_u.afs.state = AFS_LOCK_GRANTED; 514 goto vnode_is_locked_u; 515 } 516 517 if (vnode->lock_type == AFS_LOCK_WRITE) { 518 _debug("instant writelock"); 519 list_move_tail(&fl->fl_u.afs.link, &vnode->granted_locks); 520 fl->fl_u.afs.state = AFS_LOCK_GRANTED; 521 goto vnode_is_locked_u; 522 } 523 } 524 525 if (vnode->lock_state == AFS_VNODE_LOCK_NONE && 526 !(fl->c.flc_flags & FL_SLEEP)) { 527 ret = -EAGAIN; 528 if (type == AFS_LOCK_READ) { 529 if (vnode->status.lock_count == -1) 530 goto lock_is_contended; /* Write locked */ 531 } else { 532 if (vnode->status.lock_count != 0) 533 goto lock_is_contended; /* Locked */ 534 } 535 } 536 537 if (vnode->lock_state != AFS_VNODE_LOCK_NONE) 538 goto need_to_wait; 539 540 try_to_lock: 541 /* We don't have a lock on this vnode and we aren't currently waiting 542 * for one either, so ask the server for a lock. 543 * 544 * Note that we need to be careful if we get interrupted by a signal 545 * after dispatching the request as we may still get the lock, even 546 * though we don't wait for the reply (it's not too bad a problem - the 547 * lock will expire in 5 mins anyway). 548 */ 549 trace_afs_flock_ev(vnode, fl, afs_flock_try_to_lock, 0); 550 vnode->lock_key = key_get(key); 551 vnode->lock_type = type; 552 afs_set_lock_state(vnode, AFS_VNODE_LOCK_SETTING); 553 spin_unlock(&vnode->lock); 554 555 ret = afs_set_lock(vnode, key, type); /* RPC */ 556 557 spin_lock(&vnode->lock); 558 switch (ret) { 559 case -EKEYREJECTED: 560 case -EKEYEXPIRED: 561 case -EKEYREVOKED: 562 case -EPERM: 563 case -EACCES: 564 fl->fl_u.afs.state = ret; 565 trace_afs_flock_ev(vnode, fl, afs_flock_fail_perm, ret); 566 list_del_init(&fl->fl_u.afs.link); 567 afs_next_locker(vnode, ret); 568 goto error_unlock; 569 570 case -ENOENT: 571 fl->fl_u.afs.state = ret; 572 trace_afs_flock_ev(vnode, fl, afs_flock_fail_other, ret); 573 list_del_init(&fl->fl_u.afs.link); 574 afs_kill_lockers_enoent(vnode); 575 goto error_unlock; 576 577 default: 578 fl->fl_u.afs.state = ret; 579 trace_afs_flock_ev(vnode, fl, afs_flock_fail_other, ret); 580 list_del_init(&fl->fl_u.afs.link); 581 afs_next_locker(vnode, 0); 582 goto error_unlock; 583 584 case -EWOULDBLOCK: 585 /* The server doesn't have a lock-waiting queue, so the client 586 * will have to retry. The server will break the outstanding 587 * callbacks on a file when a lock is released. 588 */ 589 ASSERT(list_empty(&vnode->granted_locks)); 590 ASSERTCMP(vnode->pending_locks.next, ==, &fl->fl_u.afs.link); 591 goto lock_is_contended; 592 593 case 0: 594 afs_set_lock_state(vnode, AFS_VNODE_LOCK_GRANTED); 595 trace_afs_flock_ev(vnode, fl, afs_flock_acquired, type); 596 afs_grant_locks(vnode); 597 goto vnode_is_locked_u; 598 } 599 600 vnode_is_locked_u: 601 spin_unlock(&vnode->lock); 602 vnode_is_locked: 603 /* the lock has been granted by the server... */ 604 ASSERTCMP(fl->fl_u.afs.state, ==, AFS_LOCK_GRANTED); 605 606 skip_server_lock: 607 /* ... but the VFS still needs to distribute access on this client. */ 608 trace_afs_flock_ev(vnode, fl, afs_flock_vfs_locking, 0); 609 ret = locks_lock_file_wait(file, fl); 610 trace_afs_flock_ev(vnode, fl, afs_flock_vfs_lock, ret); 611 if (ret < 0) 612 goto vfs_rejected_lock; 613 614 /* Again, make sure we've got a callback on this file and, again, make 615 * sure that our view of the data version is up to date (we ignore 616 * errors incurred here and deal with the consequences elsewhere). 617 */ 618 afs_validate(vnode, key); 619 _leave(" = 0"); 620 return 0; 621 622 lock_is_contended: 623 if (!(fl->c.flc_flags & FL_SLEEP)) { 624 list_del_init(&fl->fl_u.afs.link); 625 afs_next_locker(vnode, 0); 626 ret = -EAGAIN; 627 goto error_unlock; 628 } 629 630 afs_set_lock_state(vnode, AFS_VNODE_LOCK_WAITING_FOR_CB); 631 trace_afs_flock_ev(vnode, fl, afs_flock_would_block, ret); 632 queue_delayed_work(afs_lock_manager, &vnode->lock_work, HZ * 5); 633 634 need_to_wait: 635 /* We're going to have to wait. Either this client doesn't have a lock 636 * on the server yet and we need to wait for a callback to occur, or 637 * the client does have a lock on the server, but it's shared and we 638 * need an exclusive lock. 639 */ 640 spin_unlock(&vnode->lock); 641 642 trace_afs_flock_ev(vnode, fl, afs_flock_waiting, 0); 643 ret = wait_event_interruptible(fl->c.flc_wait, 644 fl->fl_u.afs.state != AFS_LOCK_PENDING); 645 trace_afs_flock_ev(vnode, fl, afs_flock_waited, ret); 646 647 if (fl->fl_u.afs.state >= 0 && fl->fl_u.afs.state != AFS_LOCK_GRANTED) { 648 spin_lock(&vnode->lock); 649 650 switch (fl->fl_u.afs.state) { 651 case AFS_LOCK_YOUR_TRY: 652 fl->fl_u.afs.state = AFS_LOCK_PENDING; 653 goto try_to_lock; 654 case AFS_LOCK_PENDING: 655 if (ret > 0) { 656 /* We need to retry the lock. We may not be 657 * notified by the server if it just expired 658 * rather than being released. 659 */ 660 ASSERTCMP(vnode->lock_state, ==, AFS_VNODE_LOCK_WAITING_FOR_CB); 661 afs_set_lock_state(vnode, AFS_VNODE_LOCK_SETTING); 662 fl->fl_u.afs.state = AFS_LOCK_PENDING; 663 goto try_to_lock; 664 } 665 goto error_unlock; 666 case AFS_LOCK_GRANTED: 667 default: 668 break; 669 } 670 671 spin_unlock(&vnode->lock); 672 } 673 674 if (fl->fl_u.afs.state == AFS_LOCK_GRANTED) 675 goto vnode_is_locked; 676 ret = fl->fl_u.afs.state; 677 goto error; 678 679 vfs_rejected_lock: 680 /* The VFS rejected the lock we just obtained, so we have to discard 681 * what we just got. We defer this to the lock manager work item to 682 * deal with. 683 */ 684 _debug("vfs refused %d", ret); 685 if (no_server_lock) 686 goto error; 687 spin_lock(&vnode->lock); 688 list_del_init(&fl->fl_u.afs.link); 689 afs_defer_unlock(vnode); 690 691 error_unlock: 692 spin_unlock(&vnode->lock); 693 error: 694 _leave(" = %d", ret); 695 return ret; 696 } 697 698 /* 699 * unlock on a file on the server 700 */ afs_do_unlk(struct file * file,struct file_lock * fl)701 static int afs_do_unlk(struct file *file, struct file_lock *fl) 702 { 703 struct afs_vnode *vnode = AFS_FS_I(file_inode(file)); 704 int ret; 705 706 _enter("{%llx:%llu},%u", vnode->fid.vid, vnode->fid.vnode, 707 fl->c.flc_type); 708 709 trace_afs_flock_op(vnode, fl, afs_flock_op_unlock); 710 711 /* Flush all pending writes before doing anything with locks. */ 712 vfs_fsync(file, 0); 713 714 ret = locks_lock_file_wait(file, fl); 715 _leave(" = %d [%u]", ret, vnode->lock_state); 716 return ret; 717 } 718 719 /* 720 * return information about a lock we currently hold, if indeed we hold one 721 */ afs_do_getlk(struct file * file,struct file_lock * fl)722 static int afs_do_getlk(struct file *file, struct file_lock *fl) 723 { 724 struct afs_vnode *vnode = AFS_FS_I(file_inode(file)); 725 struct key *key = afs_file_key(file); 726 int ret, lock_count; 727 728 _enter(""); 729 730 if (vnode->lock_state == AFS_VNODE_LOCK_DELETED) 731 return -ENOENT; 732 733 fl->c.flc_type = F_UNLCK; 734 735 /* check local lock records first */ 736 posix_test_lock(file, fl); 737 if (lock_is_unlock(fl)) { 738 /* no local locks; consult the server */ 739 ret = afs_fetch_status(vnode, key, false, NULL); 740 if (ret < 0) 741 goto error; 742 743 lock_count = READ_ONCE(vnode->status.lock_count); 744 if (lock_count != 0) { 745 if (lock_count > 0) 746 fl->c.flc_type = F_RDLCK; 747 else 748 fl->c.flc_type = F_WRLCK; 749 fl->fl_start = 0; 750 fl->fl_end = OFFSET_MAX; 751 fl->c.flc_pid = 0; 752 } 753 } 754 755 ret = 0; 756 error: 757 _leave(" = %d [%hd]", ret, fl->c.flc_type); 758 return ret; 759 } 760 761 /* 762 * manage POSIX locks on a file 763 */ afs_lock(struct file * file,int cmd,struct file_lock * fl)764 int afs_lock(struct file *file, int cmd, struct file_lock *fl) 765 { 766 struct afs_vnode *vnode = AFS_FS_I(file_inode(file)); 767 enum afs_flock_operation op; 768 int ret; 769 770 _enter("{%llx:%llu},%d,{t=%x,fl=%x,r=%Ld:%Ld}", 771 vnode->fid.vid, vnode->fid.vnode, cmd, 772 fl->c.flc_type, fl->c.flc_flags, 773 (long long) fl->fl_start, (long long) fl->fl_end); 774 775 if (IS_GETLK(cmd)) 776 return afs_do_getlk(file, fl); 777 778 fl->fl_u.afs.debug_id = atomic_inc_return(&afs_file_lock_debug_id); 779 trace_afs_flock_op(vnode, fl, afs_flock_op_lock); 780 781 if (lock_is_unlock(fl)) 782 ret = afs_do_unlk(file, fl); 783 else 784 ret = afs_do_setlk(file, fl); 785 786 switch (ret) { 787 case 0: op = afs_flock_op_return_ok; break; 788 case -EAGAIN: op = afs_flock_op_return_eagain; break; 789 case -EDEADLK: op = afs_flock_op_return_edeadlk; break; 790 default: op = afs_flock_op_return_error; break; 791 } 792 trace_afs_flock_op(vnode, fl, op); 793 return ret; 794 } 795 796 /* 797 * manage FLOCK locks on a file 798 */ afs_flock(struct file * file,int cmd,struct file_lock * fl)799 int afs_flock(struct file *file, int cmd, struct file_lock *fl) 800 { 801 struct afs_vnode *vnode = AFS_FS_I(file_inode(file)); 802 enum afs_flock_operation op; 803 int ret; 804 805 _enter("{%llx:%llu},%d,{t=%x,fl=%x}", 806 vnode->fid.vid, vnode->fid.vnode, cmd, 807 fl->c.flc_type, fl->c.flc_flags); 808 809 /* 810 * No BSD flocks over NFS allowed. 811 * Note: we could try to fake a POSIX lock request here by 812 * using ((u32) filp | 0x80000000) or some such as the pid. 813 * Not sure whether that would be unique, though, or whether 814 * that would break in other places. 815 */ 816 if (!(fl->c.flc_flags & FL_FLOCK)) 817 return -ENOLCK; 818 819 fl->fl_u.afs.debug_id = atomic_inc_return(&afs_file_lock_debug_id); 820 trace_afs_flock_op(vnode, fl, afs_flock_op_flock); 821 822 /* we're simulating flock() locks using posix locks on the server */ 823 if (lock_is_unlock(fl)) 824 ret = afs_do_unlk(file, fl); 825 else 826 ret = afs_do_setlk(file, fl); 827 828 switch (ret) { 829 case 0: op = afs_flock_op_return_ok; break; 830 case -EAGAIN: op = afs_flock_op_return_eagain; break; 831 case -EDEADLK: op = afs_flock_op_return_edeadlk; break; 832 default: op = afs_flock_op_return_error; break; 833 } 834 trace_afs_flock_op(vnode, fl, op); 835 return ret; 836 } 837 838 /* 839 * the POSIX lock management core VFS code copies the lock record and adds the 840 * copy into its own list, so we need to add that copy to the vnode's lock 841 * queue in the same place as the original (which will be deleted shortly 842 * after) 843 */ afs_fl_copy_lock(struct file_lock * new,struct file_lock * fl)844 static void afs_fl_copy_lock(struct file_lock *new, struct file_lock *fl) 845 { 846 struct afs_vnode *vnode = AFS_FS_I(file_inode(fl->c.flc_file)); 847 848 _enter(""); 849 850 new->fl_u.afs.debug_id = atomic_inc_return(&afs_file_lock_debug_id); 851 852 spin_lock(&vnode->lock); 853 trace_afs_flock_op(vnode, new, afs_flock_op_copy_lock); 854 list_add(&new->fl_u.afs.link, &fl->fl_u.afs.link); 855 spin_unlock(&vnode->lock); 856 } 857 858 /* 859 * need to remove this lock from the vnode queue when it's removed from the 860 * VFS's list 861 */ afs_fl_release_private(struct file_lock * fl)862 static void afs_fl_release_private(struct file_lock *fl) 863 { 864 struct afs_vnode *vnode = AFS_FS_I(file_inode(fl->c.flc_file)); 865 866 _enter(""); 867 868 spin_lock(&vnode->lock); 869 870 trace_afs_flock_op(vnode, fl, afs_flock_op_release_lock); 871 list_del_init(&fl->fl_u.afs.link); 872 if (list_empty(&vnode->granted_locks)) 873 afs_defer_unlock(vnode); 874 875 _debug("state %u for %p", vnode->lock_state, vnode); 876 spin_unlock(&vnode->lock); 877 } 878