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881 lines
24 KiB
881 lines
24 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* AFS file locking support |
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* |
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* Copyright (C) 2007 Red Hat, Inc. All Rights Reserved. |
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* Written by David Howells ([email protected]) |
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*/ |
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|
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#include "internal.h" |
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|
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#define AFS_LOCK_GRANTED 0 |
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#define AFS_LOCK_PENDING 1 |
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#define AFS_LOCK_YOUR_TRY 2 |
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struct workqueue_struct *afs_lock_manager; |
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|
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static void afs_next_locker(struct afs_vnode *vnode, int error); |
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static void afs_fl_copy_lock(struct file_lock *new, struct file_lock *fl); |
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static void afs_fl_release_private(struct file_lock *fl); |
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static const struct file_lock_operations afs_lock_ops = { |
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.fl_copy_lock = afs_fl_copy_lock, |
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.fl_release_private = afs_fl_release_private, |
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}; |
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static inline void afs_set_lock_state(struct afs_vnode *vnode, enum afs_lock_state state) |
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{ |
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_debug("STATE %u -> %u", vnode->lock_state, state); |
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vnode->lock_state = state; |
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} |
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static atomic_t afs_file_lock_debug_id; |
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/* |
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* if the callback is broken on this vnode, then the lock may now be available |
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*/ |
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void afs_lock_may_be_available(struct afs_vnode *vnode) |
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{ |
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_enter("{%llx:%llu}", vnode->fid.vid, vnode->fid.vnode); |
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spin_lock(&vnode->lock); |
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if (vnode->lock_state == AFS_VNODE_LOCK_WAITING_FOR_CB) |
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afs_next_locker(vnode, 0); |
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trace_afs_flock_ev(vnode, NULL, afs_flock_callback_break, 0); |
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spin_unlock(&vnode->lock); |
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} |
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/* |
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* the lock will time out in 5 minutes unless we extend it, so schedule |
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* extension in a bit less than that time |
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*/ |
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static void afs_schedule_lock_extension(struct afs_vnode *vnode) |
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{ |
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ktime_t expires_at, now, duration; |
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u64 duration_j; |
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expires_at = ktime_add_ms(vnode->locked_at, AFS_LOCKWAIT * 1000 / 2); |
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now = ktime_get_real(); |
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duration = ktime_sub(expires_at, now); |
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if (duration <= 0) |
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duration_j = 0; |
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else |
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duration_j = nsecs_to_jiffies(ktime_to_ns(duration)); |
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queue_delayed_work(afs_lock_manager, &vnode->lock_work, duration_j); |
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} |
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/* |
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* In the case of successful completion of a lock operation, record the time |
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* the reply appeared and start the lock extension timer. |
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*/ |
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void afs_lock_op_done(struct afs_call *call) |
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{ |
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struct afs_operation *op = call->op; |
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struct afs_vnode *vnode = op->file[0].vnode; |
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if (call->error == 0) { |
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spin_lock(&vnode->lock); |
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trace_afs_flock_ev(vnode, NULL, afs_flock_timestamp, 0); |
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vnode->locked_at = call->reply_time; |
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afs_schedule_lock_extension(vnode); |
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spin_unlock(&vnode->lock); |
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} |
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} |
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/* |
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* grant one or more locks (readlocks are allowed to jump the queue if the |
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* first lock in the queue is itself a readlock) |
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* - the caller must hold the vnode lock |
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*/ |
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static void afs_grant_locks(struct afs_vnode *vnode) |
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{ |
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struct file_lock *p, *_p; |
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bool exclusive = (vnode->lock_type == AFS_LOCK_WRITE); |
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list_for_each_entry_safe(p, _p, &vnode->pending_locks, fl_u.afs.link) { |
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if (!exclusive && p->fl_type == F_WRLCK) |
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continue; |
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list_move_tail(&p->fl_u.afs.link, &vnode->granted_locks); |
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p->fl_u.afs.state = AFS_LOCK_GRANTED; |
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trace_afs_flock_op(vnode, p, afs_flock_op_grant); |
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wake_up(&p->fl_wait); |
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} |
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} |
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/* |
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* If an error is specified, reject every pending lock that matches the |
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* authentication and type of the lock we failed to get. If there are any |
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* remaining lockers, try to wake up one of them to have a go. |
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*/ |
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static void afs_next_locker(struct afs_vnode *vnode, int error) |
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{ |
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struct file_lock *p, *_p, *next = NULL; |
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struct key *key = vnode->lock_key; |
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unsigned int fl_type = F_RDLCK; |
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_enter(""); |
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if (vnode->lock_type == AFS_LOCK_WRITE) |
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fl_type = F_WRLCK; |
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list_for_each_entry_safe(p, _p, &vnode->pending_locks, fl_u.afs.link) { |
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if (error && |
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p->fl_type == fl_type && |
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afs_file_key(p->fl_file) == key) { |
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list_del_init(&p->fl_u.afs.link); |
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p->fl_u.afs.state = error; |
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wake_up(&p->fl_wait); |
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} |
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/* Select the next locker to hand off to. */ |
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if (next && |
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(next->fl_type == F_WRLCK || p->fl_type == F_RDLCK)) |
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continue; |
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next = p; |
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} |
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vnode->lock_key = NULL; |
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key_put(key); |
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if (next) { |
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afs_set_lock_state(vnode, AFS_VNODE_LOCK_SETTING); |
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next->fl_u.afs.state = AFS_LOCK_YOUR_TRY; |
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trace_afs_flock_op(vnode, next, afs_flock_op_wake); |
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wake_up(&next->fl_wait); |
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} else { |
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afs_set_lock_state(vnode, AFS_VNODE_LOCK_NONE); |
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trace_afs_flock_ev(vnode, NULL, afs_flock_no_lockers, 0); |
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} |
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_leave(""); |
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} |
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/* |
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* Kill off all waiters in the the pending lock queue due to the vnode being |
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* deleted. |
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*/ |
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static void afs_kill_lockers_enoent(struct afs_vnode *vnode) |
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{ |
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struct file_lock *p; |
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afs_set_lock_state(vnode, AFS_VNODE_LOCK_DELETED); |
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while (!list_empty(&vnode->pending_locks)) { |
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p = list_entry(vnode->pending_locks.next, |
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struct file_lock, fl_u.afs.link); |
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list_del_init(&p->fl_u.afs.link); |
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p->fl_u.afs.state = -ENOENT; |
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wake_up(&p->fl_wait); |
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} |
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key_put(vnode->lock_key); |
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vnode->lock_key = NULL; |
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} |
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static void afs_lock_success(struct afs_operation *op) |
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{ |
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_enter("op=%08x", op->debug_id); |
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afs_vnode_commit_status(op, &op->file[0]); |
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} |
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static const struct afs_operation_ops afs_set_lock_operation = { |
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.issue_afs_rpc = afs_fs_set_lock, |
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.issue_yfs_rpc = yfs_fs_set_lock, |
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.success = afs_lock_success, |
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.aborted = afs_check_for_remote_deletion, |
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}; |
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/* |
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* Get a lock on a file |
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*/ |
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static int afs_set_lock(struct afs_vnode *vnode, struct key *key, |
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afs_lock_type_t type) |
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{ |
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struct afs_operation *op; |
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_enter("%s{%llx:%llu.%u},%x,%u", |
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vnode->volume->name, |
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vnode->fid.vid, |
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vnode->fid.vnode, |
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vnode->fid.unique, |
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key_serial(key), type); |
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op = afs_alloc_operation(key, vnode->volume); |
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if (IS_ERR(op)) |
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return PTR_ERR(op); |
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afs_op_set_vnode(op, 0, vnode); |
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op->lock.type = type; |
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op->ops = &afs_set_lock_operation; |
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return afs_do_sync_operation(op); |
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} |
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static const struct afs_operation_ops afs_extend_lock_operation = { |
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.issue_afs_rpc = afs_fs_extend_lock, |
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.issue_yfs_rpc = yfs_fs_extend_lock, |
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.success = afs_lock_success, |
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}; |
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/* |
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* Extend a lock on a file |
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*/ |
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static int afs_extend_lock(struct afs_vnode *vnode, struct key *key) |
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{ |
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struct afs_operation *op; |
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_enter("%s{%llx:%llu.%u},%x", |
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vnode->volume->name, |
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vnode->fid.vid, |
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vnode->fid.vnode, |
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vnode->fid.unique, |
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key_serial(key)); |
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op = afs_alloc_operation(key, vnode->volume); |
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if (IS_ERR(op)) |
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return PTR_ERR(op); |
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afs_op_set_vnode(op, 0, vnode); |
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op->flags |= AFS_OPERATION_UNINTR; |
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op->ops = &afs_extend_lock_operation; |
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return afs_do_sync_operation(op); |
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} |
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static const struct afs_operation_ops afs_release_lock_operation = { |
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.issue_afs_rpc = afs_fs_release_lock, |
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.issue_yfs_rpc = yfs_fs_release_lock, |
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.success = afs_lock_success, |
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}; |
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/* |
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* Release a lock on a file |
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*/ |
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static int afs_release_lock(struct afs_vnode *vnode, struct key *key) |
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{ |
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struct afs_operation *op; |
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_enter("%s{%llx:%llu.%u},%x", |
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vnode->volume->name, |
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vnode->fid.vid, |
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vnode->fid.vnode, |
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vnode->fid.unique, |
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key_serial(key)); |
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op = afs_alloc_operation(key, vnode->volume); |
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if (IS_ERR(op)) |
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return PTR_ERR(op); |
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afs_op_set_vnode(op, 0, vnode); |
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op->flags |= AFS_OPERATION_UNINTR; |
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op->ops = &afs_release_lock_operation; |
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return afs_do_sync_operation(op); |
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} |
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/* |
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* do work for a lock, including: |
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* - probing for a lock we're waiting on but didn't get immediately |
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* - extending a lock that's close to timing out |
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*/ |
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void afs_lock_work(struct work_struct *work) |
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{ |
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struct afs_vnode *vnode = |
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container_of(work, struct afs_vnode, lock_work.work); |
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struct key *key; |
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int ret; |
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_enter("{%llx:%llu}", vnode->fid.vid, vnode->fid.vnode); |
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spin_lock(&vnode->lock); |
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again: |
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_debug("wstate %u for %p", vnode->lock_state, vnode); |
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switch (vnode->lock_state) { |
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case AFS_VNODE_LOCK_NEED_UNLOCK: |
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afs_set_lock_state(vnode, AFS_VNODE_LOCK_UNLOCKING); |
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trace_afs_flock_ev(vnode, NULL, afs_flock_work_unlocking, 0); |
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spin_unlock(&vnode->lock); |
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/* attempt to release the server lock; if it fails, we just |
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* wait 5 minutes and it'll expire anyway */ |
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ret = afs_release_lock(vnode, vnode->lock_key); |
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if (ret < 0 && vnode->lock_state != AFS_VNODE_LOCK_DELETED) { |
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trace_afs_flock_ev(vnode, NULL, afs_flock_release_fail, |
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ret); |
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printk(KERN_WARNING "AFS:" |
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" Failed to release lock on {%llx:%llx} error %d\n", |
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vnode->fid.vid, vnode->fid.vnode, ret); |
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} |
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spin_lock(&vnode->lock); |
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if (ret == -ENOENT) |
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afs_kill_lockers_enoent(vnode); |
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else |
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afs_next_locker(vnode, 0); |
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spin_unlock(&vnode->lock); |
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return; |
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/* If we've already got a lock, then it must be time to extend that |
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* lock as AFS locks time out after 5 minutes. |
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*/ |
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case AFS_VNODE_LOCK_GRANTED: |
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_debug("extend"); |
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ASSERT(!list_empty(&vnode->granted_locks)); |
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key = key_get(vnode->lock_key); |
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afs_set_lock_state(vnode, AFS_VNODE_LOCK_EXTENDING); |
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trace_afs_flock_ev(vnode, NULL, afs_flock_work_extending, 0); |
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spin_unlock(&vnode->lock); |
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ret = afs_extend_lock(vnode, key); /* RPC */ |
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key_put(key); |
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if (ret < 0) { |
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trace_afs_flock_ev(vnode, NULL, afs_flock_extend_fail, |
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ret); |
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pr_warn("AFS: Failed to extend lock on {%llx:%llx} error %d\n", |
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vnode->fid.vid, vnode->fid.vnode, ret); |
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} |
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spin_lock(&vnode->lock); |
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if (ret == -ENOENT) { |
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afs_kill_lockers_enoent(vnode); |
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spin_unlock(&vnode->lock); |
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return; |
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} |
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if (vnode->lock_state != AFS_VNODE_LOCK_EXTENDING) |
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goto again; |
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afs_set_lock_state(vnode, AFS_VNODE_LOCK_GRANTED); |
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if (ret != 0) |
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queue_delayed_work(afs_lock_manager, &vnode->lock_work, |
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HZ * 10); |
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spin_unlock(&vnode->lock); |
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_leave(" [ext]"); |
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return; |
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|
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/* If we're waiting for a callback to indicate lock release, we can't |
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* actually rely on this, so need to recheck at regular intervals. The |
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* problem is that the server might not notify us if the lock just |
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* expires (say because a client died) rather than being explicitly |
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* released. |
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*/ |
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case AFS_VNODE_LOCK_WAITING_FOR_CB: |
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_debug("retry"); |
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afs_next_locker(vnode, 0); |
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spin_unlock(&vnode->lock); |
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return; |
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case AFS_VNODE_LOCK_DELETED: |
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afs_kill_lockers_enoent(vnode); |
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spin_unlock(&vnode->lock); |
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return; |
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default: |
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/* Looks like a lock request was withdrawn. */ |
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spin_unlock(&vnode->lock); |
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_leave(" [no]"); |
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return; |
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} |
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} |
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|
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/* |
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* pass responsibility for the unlocking of a vnode on the server to the |
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* manager thread, lest a pending signal in the calling thread interrupt |
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* AF_RXRPC |
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* - the caller must hold the vnode lock |
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*/ |
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static void afs_defer_unlock(struct afs_vnode *vnode) |
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{ |
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_enter("%u", vnode->lock_state); |
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|
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if (list_empty(&vnode->granted_locks) && |
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(vnode->lock_state == AFS_VNODE_LOCK_GRANTED || |
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vnode->lock_state == AFS_VNODE_LOCK_EXTENDING)) { |
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cancel_delayed_work(&vnode->lock_work); |
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afs_set_lock_state(vnode, AFS_VNODE_LOCK_NEED_UNLOCK); |
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trace_afs_flock_ev(vnode, NULL, afs_flock_defer_unlock, 0); |
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queue_delayed_work(afs_lock_manager, &vnode->lock_work, 0); |
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} |
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} |
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|
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/* |
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* Check that our view of the file metadata is up to date and check to see |
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* whether we think that we have a locking permit. |
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*/ |
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static int afs_do_setlk_check(struct afs_vnode *vnode, struct key *key, |
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enum afs_flock_mode mode, afs_lock_type_t type) |
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{ |
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afs_access_t access; |
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int ret; |
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|
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/* Make sure we've got a callback on this file and that our view of the |
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* data version is up to date. |
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*/ |
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ret = afs_validate(vnode, key); |
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if (ret < 0) |
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return ret; |
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|
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/* Check the permission set to see if we're actually going to be |
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* allowed to get a lock on this file. |
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*/ |
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ret = afs_check_permit(vnode, key, &access); |
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if (ret < 0) |
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return ret; |
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|
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/* At a rough estimation, you need LOCK, WRITE or INSERT perm to |
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* read-lock a file and WRITE or INSERT perm to write-lock a file. |
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* |
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* We can't rely on the server to do this for us since if we want to |
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* share a read lock that we already have, we won't go the server. |
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*/ |
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if (type == AFS_LOCK_READ) { |
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if (!(access & (AFS_ACE_INSERT | AFS_ACE_WRITE | AFS_ACE_LOCK))) |
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return -EACCES; |
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} else { |
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if (!(access & (AFS_ACE_INSERT | AFS_ACE_WRITE))) |
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return -EACCES; |
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} |
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return 0; |
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} |
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|
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/* |
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* request a lock on a file on the server |
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*/ |
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static int afs_do_setlk(struct file *file, struct file_lock *fl) |
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{ |
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struct inode *inode = locks_inode(file); |
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struct afs_vnode *vnode = AFS_FS_I(inode); |
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enum afs_flock_mode mode = AFS_FS_S(inode->i_sb)->flock_mode; |
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afs_lock_type_t type; |
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struct key *key = afs_file_key(file); |
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bool partial, no_server_lock = false; |
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int ret; |
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|
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if (mode == afs_flock_mode_unset) |
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mode = afs_flock_mode_openafs; |
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|
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_enter("{%llx:%llu},%llu-%llu,%u,%u", |
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vnode->fid.vid, vnode->fid.vnode, |
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fl->fl_start, fl->fl_end, fl->fl_type, mode); |
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|
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fl->fl_ops = &afs_lock_ops; |
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INIT_LIST_HEAD(&fl->fl_u.afs.link); |
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fl->fl_u.afs.state = AFS_LOCK_PENDING; |
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|
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partial = (fl->fl_start != 0 || fl->fl_end != OFFSET_MAX); |
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type = (fl->fl_type == F_RDLCK) ? AFS_LOCK_READ : AFS_LOCK_WRITE; |
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if (mode == afs_flock_mode_write && partial) |
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type = AFS_LOCK_WRITE; |
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|
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ret = afs_do_setlk_check(vnode, key, mode, type); |
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if (ret < 0) |
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return ret; |
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|
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trace_afs_flock_op(vnode, fl, afs_flock_op_set_lock); |
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|
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/* AFS3 protocol only supports full-file locks and doesn't provide any |
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* method of upgrade/downgrade, so we need to emulate for partial-file |
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* locks. |
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* |
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* The OpenAFS client only gets a server lock for a full-file lock and |
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* keeps partial-file locks local. Allow this behaviour to be emulated |
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* (as the default). |
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*/ |
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if (mode == afs_flock_mode_local || |
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(partial && mode == afs_flock_mode_openafs)) { |
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no_server_lock = true; |
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goto skip_server_lock; |
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} |
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|
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spin_lock(&vnode->lock); |
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list_add_tail(&fl->fl_u.afs.link, &vnode->pending_locks); |
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|
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ret = -ENOENT; |
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if (vnode->lock_state == AFS_VNODE_LOCK_DELETED) |
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goto error_unlock; |
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|
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/* If we've already got a lock on the server then try to move to having |
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* the VFS grant the requested lock. Note that this means that other |
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* clients may get starved out. |
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*/ |
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_debug("try %u", vnode->lock_state); |
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if (vnode->lock_state == AFS_VNODE_LOCK_GRANTED) { |
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if (type == AFS_LOCK_READ) { |
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_debug("instant readlock"); |
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list_move_tail(&fl->fl_u.afs.link, &vnode->granted_locks); |
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fl->fl_u.afs.state = AFS_LOCK_GRANTED; |
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goto vnode_is_locked_u; |
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} |
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|
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if (vnode->lock_type == AFS_LOCK_WRITE) { |
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_debug("instant writelock"); |
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list_move_tail(&fl->fl_u.afs.link, &vnode->granted_locks); |
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fl->fl_u.afs.state = AFS_LOCK_GRANTED; |
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goto vnode_is_locked_u; |
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} |
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} |
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|
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if (vnode->lock_state == AFS_VNODE_LOCK_NONE && |
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!(fl->fl_flags & FL_SLEEP)) { |
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ret = -EAGAIN; |
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if (type == AFS_LOCK_READ) { |
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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); |
|
}
|
|
|