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1// SPDX-License-Identifier: GPL-2.0-or-later2/* AFS file locking support3 *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 011#define AFS_LOCK_PENDING 112#define AFS_LOCK_YOUR_TRY 213 14struct workqueue_struct *afs_lock_manager;15 16static void afs_next_locker(struct afs_vnode *vnode, int error);17static void afs_fl_copy_lock(struct file_lock *new, struct file_lock *fl);18static void afs_fl_release_private(struct file_lock *fl);19 20static 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 25static 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 31static atomic_t afs_file_lock_debug_id;32 33/*34 * if the callback is broken on this vnode, then the lock may now be available35 */36void 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 schedule49 * extension in a bit less than that time50 */51static 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 else62 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 time69 * the reply appeared and start the lock extension timer.70 */71void 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 the87 * first lock in the queue is itself a readlock)88 * - the caller must hold the vnode lock89 */90static 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 the108 * authentication and type of the lock we failed to get. If there are any109 * remaining lockers, try to wake up one of them to have a go.110 */111static 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 being155 * deleted.156 */157static 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 175static 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 181static 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 file190 */191static 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 214static 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 file222 */223static 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 245static 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 file253 */254static 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 immediately279 * - extending a lock that's close to timing out280 */281void 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 292again: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 just301 * 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 else315 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 that320 * 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't362 * actually rely on this, so need to recheck at regular intervals. The363 * problem is that the server might not notify us if the lock just364 * expires (say because a client died) rather than being explicitly365 * 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 the388 * manager thread, lest a pending signal in the calling thread interrupt389 * AF_RXRPC390 * - the caller must hold the vnode lock391 */392static 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 see409 * whether we think that we have a locking permit.410 */411static 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 the418 * 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 be425 * 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 to432 * 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 to435 * 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 server450 */451static 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 any484 * method of upgrade/downgrade, so we need to emulate for partial-file485 * locks.486 *487 * The OpenAFS client only gets a server lock for a full-file lock and488 * keeps partial-file locks local. Allow this behaviour to be emulated489 * (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 having505 * the VFS grant the requested lock. Note that this means that other506 * 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 540try_to_lock:541 /* We don't have a lock on this vnode and we aren't currently waiting542 * 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 signal545 * after dispatching the request as we may still get the lock, even546 * though we don't wait for the reply (it's not too bad a problem - the547 * 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 client586 * will have to retry. The server will break the outstanding587 * 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 600vnode_is_locked_u:601 spin_unlock(&vnode->lock);602vnode_is_locked:603 /* the lock has been granted by the server... */604 ASSERTCMP(fl->fl_u.afs.state, ==, AFS_LOCK_GRANTED);605 606skip_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, make615 * sure that our view of the data version is up to date (we ignore616 * errors incurred here and deal with the consequences elsewhere).617 */618 afs_validate(vnode, key);619 _leave(" = 0");620 return 0;621 622lock_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 634need_to_wait:635 /* We're going to have to wait. Either this client doesn't have a lock636 * on the server yet and we need to wait for a callback to occur, or637 * the client does have a lock on the server, but it's shared and we638 * 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 be657 * notified by the server if it just expired658 * 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 679vfs_rejected_lock:680 /* The VFS rejected the lock we just obtained, so we have to discard681 * what we just got. We defer this to the lock manager work item to682 * 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 691error_unlock:692 spin_unlock(&vnode->lock);693error:694 _leave(" = %d", ret);695 return ret;696}697 698/*699 * unlock on a file on the server700 */701static 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 one721 */722static 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 else748 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;756error:757 _leave(" = %d [%hd]", ret, fl->c.flc_type);758 return ret;759}760 761/*762 * manage POSIX locks on a file763 */764int 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 else784 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 file798 */799int 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 by812 * using ((u32) filp | 0x80000000) or some such as the pid.813 * Not sure whether that would be unique, though, or whether814 * 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 else826 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 the840 * copy into its own list, so we need to add that copy to the vnode's lock841 * queue in the same place as the original (which will be deleted shortly842 * after)843 */844static 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 the860 * VFS's list861 */862static 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