| // SPDX-License-Identifier: GPL-2.0-or-later |
| /* AFS file locking support |
| * |
| * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved. |
| * Written by David Howells (dhowells@redhat.com) |
| */ |
| |
| #include "internal.h" |
| |
| #define AFS_LOCK_GRANTED 0 |
| #define AFS_LOCK_PENDING 1 |
| #define AFS_LOCK_YOUR_TRY 2 |
| |
| struct workqueue_struct *afs_lock_manager; |
| |
| static void afs_next_locker(struct afs_vnode *vnode, int error); |
| static void afs_fl_copy_lock(struct file_lock *new, struct file_lock *fl); |
| static void afs_fl_release_private(struct file_lock *fl); |
| |
| static const struct file_lock_operations afs_lock_ops = { |
| .fl_copy_lock = afs_fl_copy_lock, |
| .fl_release_private = afs_fl_release_private, |
| }; |
| |
| static inline void afs_set_lock_state(struct afs_vnode *vnode, enum afs_lock_state state) |
| { |
| _debug("STATE %u -> %u", vnode->lock_state, state); |
| vnode->lock_state = state; |
| } |
| |
| static atomic_t afs_file_lock_debug_id; |
| |
| /* |
| * if the callback is broken on this vnode, then the lock may now be available |
| */ |
| void afs_lock_may_be_available(struct afs_vnode *vnode) |
| { |
| _enter("{%llx:%llu}", vnode->fid.vid, vnode->fid.vnode); |
| |
| spin_lock(&vnode->lock); |
| if (vnode->lock_state == AFS_VNODE_LOCK_WAITING_FOR_CB) |
| afs_next_locker(vnode, 0); |
| trace_afs_flock_ev(vnode, NULL, afs_flock_callback_break, 0); |
| spin_unlock(&vnode->lock); |
| } |
| |
| /* |
| * the lock will time out in 5 minutes unless we extend it, so schedule |
| * extension in a bit less than that time |
| */ |
| static void afs_schedule_lock_extension(struct afs_vnode *vnode) |
| { |
| ktime_t expires_at, now, duration; |
| u64 duration_j; |
| |
| expires_at = ktime_add_ms(vnode->locked_at, AFS_LOCKWAIT * 1000 / 2); |
| now = ktime_get_real(); |
| duration = ktime_sub(expires_at, now); |
| if (duration <= 0) |
| duration_j = 0; |
| else |
| duration_j = nsecs_to_jiffies(ktime_to_ns(duration)); |
| |
| queue_delayed_work(afs_lock_manager, &vnode->lock_work, duration_j); |
| } |
| |
| /* |
| * In the case of successful completion of a lock operation, record the time |
| * the reply appeared and start the lock extension timer. |
| */ |
| void afs_lock_op_done(struct afs_call *call) |
| { |
| struct afs_vnode *vnode = call->lvnode; |
| |
| if (call->error == 0) { |
| spin_lock(&vnode->lock); |
| trace_afs_flock_ev(vnode, NULL, afs_flock_timestamp, 0); |
| vnode->locked_at = call->issue_time; |
| afs_schedule_lock_extension(vnode); |
| spin_unlock(&vnode->lock); |
| } |
| } |
| |
| /* |
| * grant one or more locks (readlocks are allowed to jump the queue if the |
| * first lock in the queue is itself a readlock) |
| * - the caller must hold the vnode lock |
| */ |
| static void afs_grant_locks(struct afs_vnode *vnode) |
| { |
| struct file_lock *p, *_p; |
| bool exclusive = (vnode->lock_type == AFS_LOCK_WRITE); |
| |
| list_for_each_entry_safe(p, _p, &vnode->pending_locks, fl_u.afs.link) { |
| if (!exclusive && p->fl_type == F_WRLCK) |
| continue; |
| |
| list_move_tail(&p->fl_u.afs.link, &vnode->granted_locks); |
| p->fl_u.afs.state = AFS_LOCK_GRANTED; |
| trace_afs_flock_op(vnode, p, afs_flock_op_grant); |
| wake_up(&p->fl_wait); |
| } |
| } |
| |
| /* |
| * If an error is specified, reject every pending lock that matches the |
| * authentication and type of the lock we failed to get. If there are any |
| * remaining lockers, try to wake up one of them to have a go. |
| */ |
| static void afs_next_locker(struct afs_vnode *vnode, int error) |
| { |
| struct file_lock *p, *_p, *next = NULL; |
| struct key *key = vnode->lock_key; |
| unsigned int fl_type = F_RDLCK; |
| |
| _enter(""); |
| |
| if (vnode->lock_type == AFS_LOCK_WRITE) |
| fl_type = F_WRLCK; |
| |
| list_for_each_entry_safe(p, _p, &vnode->pending_locks, fl_u.afs.link) { |
| if (error && |
| p->fl_type == fl_type && |
| afs_file_key(p->fl_file) == key) { |
| list_del_init(&p->fl_u.afs.link); |
| p->fl_u.afs.state = error; |
| wake_up(&p->fl_wait); |
| } |
| |
| /* Select the next locker to hand off to. */ |
| if (next && |
| (next->fl_type == F_WRLCK || p->fl_type == F_RDLCK)) |
| continue; |
| next = p; |
| } |
| |
| vnode->lock_key = NULL; |
| key_put(key); |
| |
| if (next) { |
| afs_set_lock_state(vnode, AFS_VNODE_LOCK_SETTING); |
| next->fl_u.afs.state = AFS_LOCK_YOUR_TRY; |
| trace_afs_flock_op(vnode, next, afs_flock_op_wake); |
| wake_up(&next->fl_wait); |
| } else { |
| afs_set_lock_state(vnode, AFS_VNODE_LOCK_NONE); |
| trace_afs_flock_ev(vnode, NULL, afs_flock_no_lockers, 0); |
| } |
| |
| _leave(""); |
| } |
| |
| /* |
| * Kill off all waiters in the the pending lock queue due to the vnode being |
| * deleted. |
| */ |
| static void afs_kill_lockers_enoent(struct afs_vnode *vnode) |
| { |
| struct file_lock *p; |
| |
| afs_set_lock_state(vnode, AFS_VNODE_LOCK_DELETED); |
| |
| while (!list_empty(&vnode->pending_locks)) { |
| p = list_entry(vnode->pending_locks.next, |
| struct file_lock, fl_u.afs.link); |
| list_del_init(&p->fl_u.afs.link); |
| p->fl_u.afs.state = -ENOENT; |
| wake_up(&p->fl_wait); |
| } |
| |
| key_put(vnode->lock_key); |
| vnode->lock_key = NULL; |
| } |
| |
| /* |
| * Get a lock on a file |
| */ |
| static int afs_set_lock(struct afs_vnode *vnode, struct key *key, |
| afs_lock_type_t type) |
| { |
| struct afs_status_cb *scb; |
| struct afs_fs_cursor fc; |
| int ret; |
| |
| _enter("%s{%llx:%llu.%u},%x,%u", |
| vnode->volume->name, |
| vnode->fid.vid, |
| vnode->fid.vnode, |
| vnode->fid.unique, |
| key_serial(key), type); |
| |
| scb = kzalloc(sizeof(struct afs_status_cb), GFP_KERNEL); |
| if (!scb) |
| return -ENOMEM; |
| |
| ret = -ERESTARTSYS; |
| if (afs_begin_vnode_operation(&fc, vnode, key, true)) { |
| while (afs_select_fileserver(&fc)) { |
| fc.cb_break = afs_calc_vnode_cb_break(vnode); |
| afs_fs_set_lock(&fc, type, scb); |
| } |
| |
| afs_check_for_remote_deletion(&fc, vnode); |
| afs_vnode_commit_status(&fc, vnode, fc.cb_break, NULL, scb); |
| ret = afs_end_vnode_operation(&fc); |
| } |
| |
| kfree(scb); |
| _leave(" = %d", ret); |
| return ret; |
| } |
| |
| /* |
| * Extend a lock on a file |
| */ |
| static int afs_extend_lock(struct afs_vnode *vnode, struct key *key) |
| { |
| struct afs_status_cb *scb; |
| struct afs_fs_cursor fc; |
| int ret; |
| |
| _enter("%s{%llx:%llu.%u},%x", |
| vnode->volume->name, |
| vnode->fid.vid, |
| vnode->fid.vnode, |
| vnode->fid.unique, |
| key_serial(key)); |
| |
| scb = kzalloc(sizeof(struct afs_status_cb), GFP_KERNEL); |
| if (!scb) |
| return -ENOMEM; |
| |
| ret = -ERESTARTSYS; |
| if (afs_begin_vnode_operation(&fc, vnode, key, false)) { |
| while (afs_select_current_fileserver(&fc)) { |
| fc.cb_break = afs_calc_vnode_cb_break(vnode); |
| afs_fs_extend_lock(&fc, scb); |
| } |
| |
| afs_check_for_remote_deletion(&fc, vnode); |
| afs_vnode_commit_status(&fc, vnode, fc.cb_break, NULL, scb); |
| ret = afs_end_vnode_operation(&fc); |
| } |
| |
| kfree(scb); |
| _leave(" = %d", ret); |
| return ret; |
| } |
| |
| /* |
| * Release a lock on a file |
| */ |
| static int afs_release_lock(struct afs_vnode *vnode, struct key *key) |
| { |
| struct afs_status_cb *scb; |
| struct afs_fs_cursor fc; |
| int ret; |
| |
| _enter("%s{%llx:%llu.%u},%x", |
| vnode->volume->name, |
| vnode->fid.vid, |
| vnode->fid.vnode, |
| vnode->fid.unique, |
| key_serial(key)); |
| |
| scb = kzalloc(sizeof(struct afs_status_cb), GFP_KERNEL); |
| if (!scb) |
| return -ENOMEM; |
| |
| ret = -ERESTARTSYS; |
| if (afs_begin_vnode_operation(&fc, vnode, key, false)) { |
| while (afs_select_current_fileserver(&fc)) { |
| fc.cb_break = afs_calc_vnode_cb_break(vnode); |
| afs_fs_release_lock(&fc, scb); |
| } |
| |
| afs_check_for_remote_deletion(&fc, vnode); |
| afs_vnode_commit_status(&fc, vnode, fc.cb_break, NULL, scb); |
| ret = afs_end_vnode_operation(&fc); |
| } |
| |
| kfree(scb); |
| _leave(" = %d", ret); |
| return ret; |
| } |
| |
| /* |
| * do work for a lock, including: |
| * - probing for a lock we're waiting on but didn't get immediately |
| * - extending a lock that's close to timing out |
| */ |
| void afs_lock_work(struct work_struct *work) |
| { |
| struct afs_vnode *vnode = |
| container_of(work, struct afs_vnode, lock_work.work); |
| struct key *key; |
| int ret; |
| |
| _enter("{%llx:%llu}", vnode->fid.vid, vnode->fid.vnode); |
| |
| spin_lock(&vnode->lock); |
| |
| again: |
| _debug("wstate %u for %p", vnode->lock_state, vnode); |
| switch (vnode->lock_state) { |
| case AFS_VNODE_LOCK_NEED_UNLOCK: |
| afs_set_lock_state(vnode, AFS_VNODE_LOCK_UNLOCKING); |
| trace_afs_flock_ev(vnode, NULL, afs_flock_work_unlocking, 0); |
| spin_unlock(&vnode->lock); |
| |
| /* attempt to release the server lock; if it fails, we just |
| * wait 5 minutes and it'll expire anyway */ |
| ret = afs_release_lock(vnode, vnode->lock_key); |
| if (ret < 0 && vnode->lock_state != AFS_VNODE_LOCK_DELETED) { |
| trace_afs_flock_ev(vnode, NULL, afs_flock_release_fail, |
| ret); |
| printk(KERN_WARNING "AFS:" |
| " Failed to release lock on {%llx:%llx} error %d\n", |
| vnode->fid.vid, vnode->fid.vnode, ret); |
| } |
| |
| spin_lock(&vnode->lock); |
| if (ret == -ENOENT) |
| afs_kill_lockers_enoent(vnode); |
| else |
| afs_next_locker(vnode, 0); |
| spin_unlock(&vnode->lock); |
| return; |
| |
| /* If we've already got a lock, then it must be time to extend that |
| * lock as AFS locks time out after 5 minutes. |
| */ |
| case AFS_VNODE_LOCK_GRANTED: |
| _debug("extend"); |
| |
| ASSERT(!list_empty(&vnode->granted_locks)); |
| |
| key = key_get(vnode->lock_key); |
| afs_set_lock_state(vnode, AFS_VNODE_LOCK_EXTENDING); |
| trace_afs_flock_ev(vnode, NULL, afs_flock_work_extending, 0); |
| spin_unlock(&vnode->lock); |
| |
| ret = afs_extend_lock(vnode, key); /* RPC */ |
| key_put(key); |
| |
| if (ret < 0) { |
| trace_afs_flock_ev(vnode, NULL, afs_flock_extend_fail, |
| ret); |
| pr_warning("AFS: Failed to extend lock on {%llx:%llx} error %d\n", |
| vnode->fid.vid, vnode->fid.vnode, ret); |
| } |
| |
| spin_lock(&vnode->lock); |
| |
| if (ret == -ENOENT) { |
| afs_kill_lockers_enoent(vnode); |
| spin_unlock(&vnode->lock); |
| return; |
| } |
| |
| if (vnode->lock_state != AFS_VNODE_LOCK_EXTENDING) |
| goto again; |
| afs_set_lock_state(vnode, AFS_VNODE_LOCK_GRANTED); |
| |
| if (ret != 0) |
| queue_delayed_work(afs_lock_manager, &vnode->lock_work, |
| HZ * 10); |
| spin_unlock(&vnode->lock); |
| _leave(" [ext]"); |
| return; |
| |
| /* If we're waiting for a callback to indicate lock release, we can't |
| * actually rely on this, so need to recheck at regular intervals. The |
| * problem is that the server might not notify us if the lock just |
| * expires (say because a client died) rather than being explicitly |
| * released. |
| */ |
| case AFS_VNODE_LOCK_WAITING_FOR_CB: |
| _debug("retry"); |
| afs_next_locker(vnode, 0); |
| spin_unlock(&vnode->lock); |
| return; |
| |
| case AFS_VNODE_LOCK_DELETED: |
| afs_kill_lockers_enoent(vnode); |
| spin_unlock(&vnode->lock); |
| return; |
| |
| /* Fall through */ |
| default: |
| /* Looks like a lock request was withdrawn. */ |
| spin_unlock(&vnode->lock); |
| _leave(" [no]"); |
| return; |
| } |
| } |
| |
| /* |
| * pass responsibility for the unlocking of a vnode on the server to the |
| * manager thread, lest a pending signal in the calling thread interrupt |
| * AF_RXRPC |
| * - the caller must hold the vnode lock |
| */ |
| static void afs_defer_unlock(struct afs_vnode *vnode) |
| { |
| _enter("%u", vnode->lock_state); |
| |
| if (list_empty(&vnode->granted_locks) && |
| (vnode->lock_state == AFS_VNODE_LOCK_GRANTED || |
| vnode->lock_state == AFS_VNODE_LOCK_EXTENDING)) { |
| cancel_delayed_work(&vnode->lock_work); |
| |
| afs_set_lock_state(vnode, AFS_VNODE_LOCK_NEED_UNLOCK); |
| trace_afs_flock_ev(vnode, NULL, afs_flock_defer_unlock, 0); |
| queue_delayed_work(afs_lock_manager, &vnode->lock_work, 0); |
| } |
| } |
| |
| /* |
| * Check that our view of the file metadata is up to date and check to see |
| * whether we think that we have a locking permit. |
| */ |
| static int afs_do_setlk_check(struct afs_vnode *vnode, struct key *key, |
| enum afs_flock_mode mode, afs_lock_type_t type) |
| { |
| afs_access_t access; |
| int ret; |
| |
| /* Make sure we've got a callback on this file and that our view of the |
| * data version is up to date. |
| */ |
| ret = afs_validate(vnode, key); |
| if (ret < 0) |
| return ret; |
| |
| /* Check the permission set to see if we're actually going to be |
| * allowed to get a lock on this file. |
| */ |
| ret = afs_check_permit(vnode, key, &access); |
| if (ret < 0) |
| return ret; |
| |
| /* At a rough estimation, you need LOCK, WRITE or INSERT perm to |
| * read-lock a file and WRITE or INSERT perm to write-lock a file. |
| * |
| * We can't rely on the server to do this for us since if we want to |
| * share a read lock that we already have, we won't go the server. |
| */ |
| if (type == AFS_LOCK_READ) { |
| if (!(access & (AFS_ACE_INSERT | AFS_ACE_WRITE | AFS_ACE_LOCK))) |
| return -EACCES; |
| } else { |
| if (!(access & (AFS_ACE_INSERT | AFS_ACE_WRITE))) |
| return -EACCES; |
| } |
| |
| return 0; |
| } |
| |
| /* |
| * request a lock on a file on the server |
| */ |
| static int afs_do_setlk(struct file *file, struct file_lock *fl) |
| { |
| struct inode *inode = locks_inode(file); |
| struct afs_vnode *vnode = AFS_FS_I(inode); |
| enum afs_flock_mode mode = AFS_FS_S(inode->i_sb)->flock_mode; |
| afs_lock_type_t type; |
| struct key *key = afs_file_key(file); |
| bool partial, no_server_lock = false; |
| int ret; |
| |
| if (mode == afs_flock_mode_unset) |
| mode = afs_flock_mode_openafs; |
| |
| _enter("{%llx:%llu},%llu-%llu,%u,%u", |
| vnode->fid.vid, vnode->fid.vnode, |
| fl->fl_start, fl->fl_end, fl->fl_type, mode); |
| |
| fl->fl_ops = &afs_lock_ops; |
| INIT_LIST_HEAD(&fl->fl_u.afs.link); |
| fl->fl_u.afs.state = AFS_LOCK_PENDING; |
| |
| partial = (fl->fl_start != 0 || fl->fl_end != OFFSET_MAX); |
| type = (fl->fl_type == F_RDLCK) ? AFS_LOCK_READ : AFS_LOCK_WRITE; |
| if (mode == afs_flock_mode_write && partial) |
| type = AFS_LOCK_WRITE; |
| |
| ret = afs_do_setlk_check(vnode, key, mode, type); |
| if (ret < 0) |
| return ret; |
| |
| trace_afs_flock_op(vnode, fl, afs_flock_op_set_lock); |
| |
| /* AFS3 protocol only supports full-file locks and doesn't provide any |
| * method of upgrade/downgrade, so we need to emulate for partial-file |
| * locks. |
| * |
| * The OpenAFS client only gets a server lock for a full-file lock and |
| * keeps partial-file locks local. Allow this behaviour to be emulated |
| * (as the default). |
| */ |
| if (mode == afs_flock_mode_local || |
| (partial && mode == afs_flock_mode_openafs)) { |
| no_server_lock = true; |
| goto skip_server_lock; |
| } |
| |
| spin_lock(&vnode->lock); |
| list_add_tail(&fl->fl_u.afs.link, &vnode->pending_locks); |
| |
| ret = -ENOENT; |
| if (vnode->lock_state == AFS_VNODE_LOCK_DELETED) |
| goto error_unlock; |
| |
| /* If we've already got a lock on the server then try to move to having |
| * the VFS grant the requested lock. Note that this means that other |
| * clients may get starved out. |
| */ |
| _debug("try %u", vnode->lock_state); |
| if (vnode->lock_state == AFS_VNODE_LOCK_GRANTED) { |
| if (type == AFS_LOCK_READ) { |
| _debug("instant readlock"); |
| list_move_tail(&fl->fl_u.afs.link, &vnode->granted_locks); |
| fl->fl_u.afs.state = AFS_LOCK_GRANTED; |
| goto vnode_is_locked_u; |
| } |
| |
| if (vnode->lock_type == AFS_LOCK_WRITE) { |
| _debug("instant writelock"); |
| list_move_tail(&fl->fl_u.afs.link, &vnode->granted_locks); |
| fl->fl_u.afs.state = AFS_LOCK_GRANTED; |
| goto vnode_is_locked_u; |
| } |
| } |
| |
| if (vnode->lock_state == AFS_VNODE_LOCK_NONE && |
| !(fl->fl_flags & FL_SLEEP)) { |
| ret = -EAGAIN; |
| if (type == AFS_LOCK_READ) { |
| if (vnode->status.lock_count == -1) |
| goto lock_is_contended; /* Write locked */ |
| } else { |
| if (vnode->status.lock_count != 0) |
| goto lock_is_contended; /* Locked */ |
| } |
| } |
| |
| if (vnode->lock_state != AFS_VNODE_LOCK_NONE) |
| goto need_to_wait; |
| |
| try_to_lock: |
| /* We don't have a lock on this vnode and we aren't currently waiting |
| * for one either, so ask the server for a lock. |
| * |
| * Note that we need to be careful if we get interrupted by a signal |
| * after dispatching the request as we may still get the lock, even |
| * though we don't wait for the reply (it's not too bad a problem - the |
| * lock will expire in 5 mins anyway). |
| */ |
| trace_afs_flock_ev(vnode, fl, afs_flock_try_to_lock, 0); |
| vnode->lock_key = key_get(key); |
| vnode->lock_type = type; |
| afs_set_lock_state(vnode, AFS_VNODE_LOCK_SETTING); |
| spin_unlock(&vnode->lock); |
| |
| ret = afs_set_lock(vnode, key, type); /* RPC */ |
| |
| spin_lock(&vnode->lock); |
| switch (ret) { |
| case -EKEYREJECTED: |
| case -EKEYEXPIRED: |
| case -EKEYREVOKED: |
| case -EPERM: |
| case -EACCES: |
| fl->fl_u.afs.state = ret; |
| trace_afs_flock_ev(vnode, fl, afs_flock_fail_perm, ret); |
| list_del_init(&fl->fl_u.afs.link); |
| afs_next_locker(vnode, ret); |
| goto error_unlock; |
| |
| case -ENOENT: |
| fl->fl_u.afs.state = ret; |
| trace_afs_flock_ev(vnode, fl, afs_flock_fail_other, ret); |
| list_del_init(&fl->fl_u.afs.link); |
| afs_kill_lockers_enoent(vnode); |
| goto error_unlock; |
| |
| default: |
| fl->fl_u.afs.state = ret; |
| trace_afs_flock_ev(vnode, fl, afs_flock_fail_other, ret); |
| list_del_init(&fl->fl_u.afs.link); |
| afs_next_locker(vnode, 0); |
| goto error_unlock; |
| |
| case -EWOULDBLOCK: |
| /* The server doesn't have a lock-waiting queue, so the client |
| * will have to retry. The server will break the outstanding |
| * callbacks on a file when a lock is released. |
| */ |
| ASSERT(list_empty(&vnode->granted_locks)); |
| ASSERTCMP(vnode->pending_locks.next, ==, &fl->fl_u.afs.link); |
| goto lock_is_contended; |
| |
| case 0: |
| afs_set_lock_state(vnode, AFS_VNODE_LOCK_GRANTED); |
| trace_afs_flock_ev(vnode, fl, afs_flock_acquired, type); |
| afs_grant_locks(vnode); |
| goto vnode_is_locked_u; |
| } |
| |
| vnode_is_locked_u: |
| spin_unlock(&vnode->lock); |
| vnode_is_locked: |
| /* the lock has been granted by the server... */ |
| ASSERTCMP(fl->fl_u.afs.state, ==, AFS_LOCK_GRANTED); |
| |
| skip_server_lock: |
| /* ... but the VFS still needs to distribute access on this client. */ |
| trace_afs_flock_ev(vnode, fl, afs_flock_vfs_locking, 0); |
| ret = locks_lock_file_wait(file, fl); |
| trace_afs_flock_ev(vnode, fl, afs_flock_vfs_lock, ret); |
| if (ret < 0) |
| goto vfs_rejected_lock; |
| |
| /* Again, make sure we've got a callback on this file and, again, make |
| * sure that our view of the data version is up to date (we ignore |
| * errors incurred here and deal with the consequences elsewhere). |
| */ |
| afs_validate(vnode, key); |
| _leave(" = 0"); |
| return 0; |
| |
| lock_is_contended: |
| if (!(fl->fl_flags & FL_SLEEP)) { |
| list_del_init(&fl->fl_u.afs.link); |
| afs_next_locker(vnode, 0); |
| ret = -EAGAIN; |
| goto error_unlock; |
| } |
| |
| afs_set_lock_state(vnode, AFS_VNODE_LOCK_WAITING_FOR_CB); |
| trace_afs_flock_ev(vnode, fl, afs_flock_would_block, ret); |
| queue_delayed_work(afs_lock_manager, &vnode->lock_work, HZ * 5); |
| |
| need_to_wait: |
| /* We're going to have to wait. Either this client doesn't have a lock |
| * on the server yet and we need to wait for a callback to occur, or |
| * the client does have a lock on the server, but it's shared and we |
| * need an exclusive lock. |
| */ |
| spin_unlock(&vnode->lock); |
| |
| trace_afs_flock_ev(vnode, fl, afs_flock_waiting, 0); |
| ret = wait_event_interruptible(fl->fl_wait, |
| fl->fl_u.afs.state != AFS_LOCK_PENDING); |
| trace_afs_flock_ev(vnode, fl, afs_flock_waited, ret); |
| |
| if (fl->fl_u.afs.state >= 0 && fl->fl_u.afs.state != AFS_LOCK_GRANTED) { |
| spin_lock(&vnode->lock); |
| |
| switch (fl->fl_u.afs.state) { |
| case AFS_LOCK_YOUR_TRY: |
| fl->fl_u.afs.state = AFS_LOCK_PENDING; |
| goto try_to_lock; |
| case AFS_LOCK_PENDING: |
| if (ret > 0) { |
| /* We need to retry the lock. We may not be |
| * notified by the server if it just expired |
| * rather than being released. |
| */ |
| ASSERTCMP(vnode->lock_state, ==, AFS_VNODE_LOCK_WAITING_FOR_CB); |
| afs_set_lock_state(vnode, AFS_VNODE_LOCK_SETTING); |
| fl->fl_u.afs.state = AFS_LOCK_PENDING; |
| goto try_to_lock; |
| } |
| goto error_unlock; |
| case AFS_LOCK_GRANTED: |
| default: |
| break; |
| } |
| |
| spin_unlock(&vnode->lock); |
| } |
| |
| if (fl->fl_u.afs.state == AFS_LOCK_GRANTED) |
| goto vnode_is_locked; |
| ret = fl->fl_u.afs.state; |
| goto error; |
| |
| vfs_rejected_lock: |
| /* The VFS rejected the lock we just obtained, so we have to discard |
| * what we just got. We defer this to the lock manager work item to |
| * deal with. |
| */ |
| _debug("vfs refused %d", ret); |
| if (no_server_lock) |
| goto error; |
| spin_lock(&vnode->lock); |
| list_del_init(&fl->fl_u.afs.link); |
| afs_defer_unlock(vnode); |
| |
| error_unlock: |
| spin_unlock(&vnode->lock); |
| error: |
| _leave(" = %d", ret); |
| return ret; |
| } |
| |
| /* |
| * unlock on a file on the server |
| */ |
| static int afs_do_unlk(struct file *file, struct file_lock *fl) |
| { |
| struct afs_vnode *vnode = AFS_FS_I(locks_inode(file)); |
| int ret; |
| |
| _enter("{%llx:%llu},%u", vnode->fid.vid, vnode->fid.vnode, fl->fl_type); |
| |
| trace_afs_flock_op(vnode, fl, afs_flock_op_unlock); |
| |
| /* Flush all pending writes before doing anything with locks. */ |
| vfs_fsync(file, 0); |
| |
| ret = locks_lock_file_wait(file, fl); |
| _leave(" = %d [%u]", ret, vnode->lock_state); |
| return ret; |
| } |
| |
| /* |
| * return information about a lock we currently hold, if indeed we hold one |
| */ |
| static int afs_do_getlk(struct file *file, struct file_lock *fl) |
| { |
| struct afs_vnode *vnode = AFS_FS_I(locks_inode(file)); |
| struct key *key = afs_file_key(file); |
| int ret, lock_count; |
| |
| _enter(""); |
| |
| if (vnode->lock_state == AFS_VNODE_LOCK_DELETED) |
| return -ENOENT; |
| |
| fl->fl_type = F_UNLCK; |
| |
| /* check local lock records first */ |
| posix_test_lock(file, fl); |
| if (fl->fl_type == F_UNLCK) { |
| /* no local locks; consult the server */ |
| ret = afs_fetch_status(vnode, key, false, NULL); |
| if (ret < 0) |
| goto error; |
| |
| lock_count = READ_ONCE(vnode->status.lock_count); |
| if (lock_count != 0) { |
| if (lock_count > 0) |
| fl->fl_type = F_RDLCK; |
| else |
| fl->fl_type = F_WRLCK; |
| fl->fl_start = 0; |
| fl->fl_end = OFFSET_MAX; |
| fl->fl_pid = 0; |
| } |
| } |
| |
| ret = 0; |
| error: |
| _leave(" = %d [%hd]", ret, fl->fl_type); |
| return ret; |
| } |
| |
| /* |
| * manage POSIX locks on a file |
| */ |
| int afs_lock(struct file *file, int cmd, struct file_lock *fl) |
| { |
| struct afs_vnode *vnode = AFS_FS_I(locks_inode(file)); |
| enum afs_flock_operation op; |
| int ret; |
| |
| _enter("{%llx:%llu},%d,{t=%x,fl=%x,r=%Ld:%Ld}", |
| vnode->fid.vid, vnode->fid.vnode, cmd, |
| fl->fl_type, fl->fl_flags, |
| (long long) fl->fl_start, (long long) fl->fl_end); |
| |
| /* AFS doesn't support mandatory locks */ |
| if (__mandatory_lock(&vnode->vfs_inode) && fl->fl_type != F_UNLCK) |
| return -ENOLCK; |
| |
| if (IS_GETLK(cmd)) |
| return afs_do_getlk(file, fl); |
| |
| fl->fl_u.afs.debug_id = atomic_inc_return(&afs_file_lock_debug_id); |
| trace_afs_flock_op(vnode, fl, afs_flock_op_lock); |
| |
| if (fl->fl_type == F_UNLCK) |
| ret = afs_do_unlk(file, fl); |
| else |
| ret = afs_do_setlk(file, fl); |
| |
| switch (ret) { |
| case 0: op = afs_flock_op_return_ok; break; |
| case -EAGAIN: op = afs_flock_op_return_eagain; break; |
| case -EDEADLK: op = afs_flock_op_return_edeadlk; break; |
| default: op = afs_flock_op_return_error; break; |
| } |
| trace_afs_flock_op(vnode, fl, op); |
| return ret; |
| } |
| |
| /* |
| * manage FLOCK locks on a file |
| */ |
| int afs_flock(struct file *file, int cmd, struct file_lock *fl) |
| { |
| struct afs_vnode *vnode = AFS_FS_I(locks_inode(file)); |
| enum afs_flock_operation op; |
| int ret; |
| |
| _enter("{%llx:%llu},%d,{t=%x,fl=%x}", |
| vnode->fid.vid, vnode->fid.vnode, cmd, |
| fl->fl_type, fl->fl_flags); |
| |
| /* |
| * No BSD flocks over NFS allowed. |
| * Note: we could try to fake a POSIX lock request here by |
| * using ((u32) filp | 0x80000000) or some such as the pid. |
| * Not sure whether that would be unique, though, or whether |
| * that would break in other places. |
| */ |
| if (!(fl->fl_flags & FL_FLOCK)) |
| return -ENOLCK; |
| |
| fl->fl_u.afs.debug_id = atomic_inc_return(&afs_file_lock_debug_id); |
| trace_afs_flock_op(vnode, fl, afs_flock_op_flock); |
| |
| /* we're simulating flock() locks using posix locks on the server */ |
| if (fl->fl_type == F_UNLCK) |
| ret = afs_do_unlk(file, fl); |
| else |
| ret = afs_do_setlk(file, fl); |
| |
| switch (ret) { |
| case 0: op = afs_flock_op_return_ok; break; |
| case -EAGAIN: op = afs_flock_op_return_eagain; break; |
| case -EDEADLK: op = afs_flock_op_return_edeadlk; break; |
| default: op = afs_flock_op_return_error; break; |
| } |
| trace_afs_flock_op(vnode, fl, op); |
| return ret; |
| } |
| |
| /* |
| * the POSIX lock management core VFS code copies the lock record and adds the |
| * copy into its own list, so we need to add that copy to the vnode's lock |
| * queue in the same place as the original (which will be deleted shortly |
| * after) |
| */ |
| static void afs_fl_copy_lock(struct file_lock *new, struct file_lock *fl) |
| { |
| struct afs_vnode *vnode = AFS_FS_I(locks_inode(fl->fl_file)); |
| |
| _enter(""); |
| |
| new->fl_u.afs.debug_id = atomic_inc_return(&afs_file_lock_debug_id); |
| |
| spin_lock(&vnode->lock); |
| trace_afs_flock_op(vnode, new, afs_flock_op_copy_lock); |
| list_add(&new->fl_u.afs.link, &fl->fl_u.afs.link); |
| spin_unlock(&vnode->lock); |
| } |
| |
| /* |
| * need to remove this lock from the vnode queue when it's removed from the |
| * VFS's list |
| */ |
| static void afs_fl_release_private(struct file_lock *fl) |
| { |
| struct afs_vnode *vnode = AFS_FS_I(locks_inode(fl->fl_file)); |
| |
| _enter(""); |
| |
| spin_lock(&vnode->lock); |
| |
| trace_afs_flock_op(vnode, fl, afs_flock_op_release_lock); |
| list_del_init(&fl->fl_u.afs.link); |
| if (list_empty(&vnode->granted_locks)) |
| afs_defer_unlock(vnode); |
| |
| _debug("state %u for %p", vnode->lock_state, vnode); |
| spin_unlock(&vnode->lock); |
| } |