aboutsummaryrefslogtreecommitdiffstats
path: root/fs/dlm
Commit message (Expand)AuthorAge
* Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-nextLinus Torvalds2012-10-02
|\
| * netlink: Rename pid to portid to avoid confusionEric W. Biederman2012-09-10
* | dlm: check the maximum size of a request from userSasha Levin2012-09-10
* | dlm: cleanup send_to_sock routineYing Xue2012-08-13
* | dlm: convert add_sock routine return value type to voidYing Xue2012-08-10
* | dlm: remove redundant variable assignmentsXue Ying2012-08-10
* | dlm: fix unlock balance warningsDavid Teigland2012-08-08
* | dlm: fix uninitialized spinlockDavid Teigland2012-08-08
* | dlm: fix deadlock between dlm_send and dlm_controldDavid Teigland2012-08-08
|/
* dlm: fix missing dir removeDavid Teigland2012-07-16
* dlm: fix conversion deadlock from recoveryDavid Teigland2012-07-16
* dlm: use wait_event_timeoutDavid Teigland2012-07-16
* dlm: fix race between remove and lookupDavid Teigland2012-07-16
* dlm: use idr instead of list for recovered rsbsDavid Teigland2012-07-16
* dlm: use rsbtbl as resource directoryDavid Teigland2012-07-16
* dlm: NULL dereference on failure in kmem_cache_create()Dan Carpenter2012-05-15
* dlm: fixes for nodir modeDavid Teigland2012-05-02
* dlm: improve error and debug messagesDavid Teigland2012-04-26
* dlm: avoid unnecessary search in search_rsbDavid Teigland2012-04-26
* dlm: limit rcom debug messagesDavid Teigland2012-04-26
* dlm: fix waiter recoveryDavid Teigland2012-04-26
* dlm: prevent connections during shutdownDavid Teigland2012-04-26
* Merge tag 'dlm-fixes-3.4' of git://git.kernel.org/pub/scm/linux/kernel/git/te...Linus Torvalds2012-04-23
|\
| * dlm: fix QUECVT when convert queue is emptyDavid Teigland2012-04-23
* | simple_open: automatically convert to simple_open()Stephen Boyd2012-04-05
|/
* Merge tag 'dlm-3.4' of git://git.kernel.org/pub/scm/linux/kernel/git/teigland...Linus Torvalds2012-03-21
|\
| * dlm: last element of dlm_local_addr[] never usedDavid Teigland2012-03-21
| * dlm: fix slow rsb search in dir recoveryDavid Teigland2012-03-08
* | dlm: Do not allocate a fd for peeloffBenjamin Poirier2012-03-08
|/
* Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tei...Linus Torvalds2012-01-10
|\
| * dlm: add recovery callbacksDavid Teigland2012-01-04
| * dlm: add node slots and generationDavid Teigland2012-01-04
| * dlm: move recovery barrier callsDavid Teigland2012-01-04
| * dlm: convert rsb list to rb_treeBob Peterson2011-11-18
* | net: remove ipv6_addr_copy()Alexey Dobriyan2011-11-22
|/
* Merge branch 'for-3.1' of git://linux-nfs.org/~bfields/linuxLinus Torvalds2011-07-26
|\
| * locks: rename lock-manager opsJ. Bruce Fields2011-07-20
* | dlm: don't limit active work itemsDavid Teigland2011-07-19
* | dlm: use workqueue for callbacksDavid Teigland2011-07-15
* | dlm: remove deadlock debug printDavid Teigland2011-07-14
* | dlm: improve rsb searchesDavid Teigland2011-07-12
* | dlm: keep lkbs in idrDavid Teigland2011-07-11
* | dlm: fix kmalloc argsDavid Teigland2011-07-11
* | dlm: don't do pointless NULL check, use kzalloc and fix order of argumentsJesper Juhl2011-07-11
* | dlm: dump address of unknown nodeMasatake YAMATO2011-07-06
* | dlm: use vmalloc for hash tablesBryn M. Reeves2011-07-01
* | dlm: show addresses in configfsMasatake YAMATO2011-06-30
|/
* Merge branch 'trivial' of git://git.kernel.org/pub/scm/linux/kernel/git/mmare...Linus Torvalds2011-05-26
|\
| * dlm: Drop __TIME__ usageMichal Marek2011-05-26
* | Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tei...Linus Torvalds2011-05-24
|\ \
ef='#n511'>511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588
/* AFS file locking support
 *
 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version
 * 2 of the License, or (at your option) any later version.
 */

#include "internal.h"

#define AFS_LOCK_GRANTED	0
#define AFS_LOCK_PENDING	1

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 struct workqueue_struct *afs_lock_manager;
static DEFINE_MUTEX(afs_lock_manager_mutex);

static const struct file_lock_operations afs_lock_ops = {
	.fl_copy_lock		= afs_fl_copy_lock,
	.fl_release_private	= afs_fl_release_private,
};

/*
 * initialise the lock manager thread if it isn't already running
 */
static int afs_init_lock_manager(void)
{
	int ret;

	ret = 0;
	if (!afs_lock_manager) {
		mutex_lock(&afs_lock_manager_mutex);
		if (!afs_lock_manager) {
			afs_lock_manager =
				create_singlethread_workqueue("kafs_lockd");
			if (!afs_lock_manager)
				ret = -ENOMEM;
		}
		mutex_unlock(&afs_lock_manager_mutex);
	}
	return ret;
}

/*
 * destroy the lock manager thread if it's running
 */
void __exit afs_kill_lock_manager(void)
{
	if (afs_lock_manager)
		destroy_workqueue(afs_lock_manager);
}

/*
 * 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("{%x:%u}", vnode->fid.vid, vnode->fid.vnode);

	queue_delayed_work(afs_lock_manager, &vnode->lock_work, 0);
}

/*
 * 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)
{
	queue_delayed_work(afs_lock_manager, &vnode->lock_work,
			   AFS_LOCKWAIT * HZ / 2);
}

/*
 * 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 *fl)
{
	struct file_lock *p, *_p;

	list_move_tail(&fl->fl_u.afs.link, &vnode->granted_locks);
	if (fl->fl_type == F_RDLCK) {
		list_for_each_entry_safe(p, _p, &vnode->pending_locks,
					 fl_u.afs.link) {
			if (p->fl_type == F_RDLCK) {
				p->fl_u.afs.state = AFS_LOCK_GRANTED;
				list_move_tail(&p->fl_u.afs.link,
					       &vnode->granted_locks);
				wake_up(&p->fl_wait);
			}
		}
	}
}

/*
 * 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 file_lock *fl;
	afs_lock_type_t type;
	struct key *key;
	int ret;

	_enter("{%x:%u}", vnode->fid.vid, vnode->fid.vnode);

	spin_lock(&vnode->lock);

	if (test_bit(AFS_VNODE_UNLOCKING, &vnode->flags)) {
		_debug("unlock");
		spin_unlock(&vnode->lock);

		/* attempt to release the server lock; if it fails, we just
		 * wait 5 minutes and it'll time out anyway */
		ret = afs_vnode_release_lock(vnode, vnode->unlock_key);
		if (ret < 0)
			printk(KERN_WARNING "AFS:"
			       " Failed to release lock on {%x:%x} error %d\n",
			       vnode->fid.vid, vnode->fid.vnode, ret);

		spin_lock(&vnode->lock);
		key_put(vnode->unlock_key);
		vnode->unlock_key = NULL;
		clear_bit(AFS_VNODE_UNLOCKING, &vnode->flags);
	}

	/* if we've got a lock, then it must be time to extend that lock as AFS
	 * locks time out after 5 minutes */
	if (!list_empty(&vnode->granted_locks)) {
		_debug("extend");

		if (test_and_set_bit(AFS_VNODE_LOCKING, &vnode->flags))
			BUG();
		fl = list_entry(vnode->granted_locks.next,
				struct file_lock, fl_u.afs.link);
		key = key_get(fl->fl_file->private_data);
		spin_unlock(&vnode->lock);

		ret = afs_vnode_extend_lock(vnode, key);
		clear_bit(AFS_VNODE_LOCKING, &vnode->flags);
		key_put(key);
		switch (ret) {
		case 0:
			afs_schedule_lock_extension(vnode);
			break;
		default:
			/* ummm... we failed to extend the lock - retry
			 * extension shortly */
			printk(KERN_WARNING "AFS:"
			       " Failed to extend lock on {%x:%x} error %d\n",
			       vnode->fid.vid, vnode->fid.vnode, ret);
			queue_delayed_work(afs_lock_manager, &vnode->lock_work,
					   HZ * 10);
			break;
		}
		_leave(" [extend]");
		return;
	}

	/* if we don't have a granted lock, then we must've been called back by
	 * the server, and so if might be possible to get a lock we're
	 * currently waiting for */
	if (!list_empty(&vnode->pending_locks)) {
		_debug("get");

		if (test_and_set_bit(AFS_VNODE_LOCKING, &vnode->flags))
			BUG();
		fl = list_entry(vnode->pending_locks.next,
				struct file_lock, fl_u.afs.link);
		key = key_get(fl->fl_file->private_data);
		type = (fl->fl_type == F_RDLCK) ?
			AFS_LOCK_READ : AFS_LOCK_WRITE;
		spin_unlock(&vnode->lock);

		ret = afs_vnode_set_lock(vnode, key, type);
		clear_bit(AFS_VNODE_LOCKING, &vnode->flags);
		switch (ret) {
		case -EWOULDBLOCK:
			_debug("blocked");
			break;
		case 0:
			_debug("acquired");
			if (type == AFS_LOCK_READ)
				set_bit(AFS_VNODE_READLOCKED, &vnode->flags);
			else
				set_bit(AFS_VNODE_WRITELOCKED, &vnode->flags);
			ret = AFS_LOCK_GRANTED;
		default:
			spin_lock(&vnode->lock);
			/* the pending lock may have been withdrawn due to a
			 * signal */
			if (list_entry(vnode->pending_locks.next,
				       struct file_lock, fl_u.afs.link) == fl) {
				fl->fl_u.afs.state = ret;
				if (ret == AFS_LOCK_GRANTED)
					afs_grant_locks(vnode, fl);
				else
					list_del_init(&fl->fl_u.afs.link);
				wake_up(&fl->fl_wait);
				spin_unlock(&vnode->lock);
			} else {
				_debug("withdrawn");
				clear_bit(AFS_VNODE_READLOCKED, &vnode->flags);
				clear_bit(AFS_VNODE_WRITELOCKED, &vnode->flags);
				spin_unlock(&vnode->lock);
				afs_vnode_release_lock(vnode, key);
				if (!list_empty(&vnode->pending_locks))
					afs_lock_may_be_available(vnode);
			}
			break;
		}
		key_put(key);
		_leave(" [pend]");
		return;
	}

	/* looks like the lock request was withdrawn on a signal */
	spin_unlock(&vnode->lock);
	_leave(" [no locks]");
}

/*
 * 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, struct key *key)
{
	cancel_delayed_work(&vnode->lock_work);
	if (!test_and_clear_bit(AFS_VNODE_READLOCKED, &vnode->flags) &&
	    !test_and_clear_bit(AFS_VNODE_WRITELOCKED, &vnode->flags))
		BUG();
	if (test_and_set_bit(AFS_VNODE_UNLOCKING, &vnode->flags))
		BUG();
	vnode->unlock_key = key_get(key);
	afs_lock_may_be_available(vnode);
}

/*
 * request a lock on a file on the server
 */
static int afs_do_setlk(struct file *file, struct file_lock *fl)
{
	struct afs_vnode *vnode = AFS_FS_I(file->f_mapping->host);
	afs_lock_type_t type;
	struct key *key = file->private_data;
	int ret;

	_enter("{%x:%u},%u", vnode->fid.vid, vnode->fid.vnode, fl->fl_type);

	/* only whole-file locks are supported */
	if (fl->fl_start != 0 || fl->fl_end != OFFSET_MAX)
		return -EINVAL;

	ret = afs_init_lock_manager();
	if (ret < 0)
		return ret;

	fl->fl_ops = &afs_lock_ops;
	INIT_LIST_HEAD(&fl->fl_u.afs.link);
	fl->fl_u.afs.state = AFS_LOCK_PENDING;

	type = (fl->fl_type == F_RDLCK) ? AFS_LOCK_READ : AFS_LOCK_WRITE;

	lock_flocks();

	/* make sure we've got a callback on this file and that our view of the
	 * data version is up to date */
	ret = afs_vnode_fetch_status(vnode, NULL, key);
	if (ret < 0)
		goto error;

	if (vnode->status.lock_count != 0 && !(fl->fl_flags & FL_SLEEP)) {
		ret = -EAGAIN;
		goto error;
	}

	spin_lock(&vnode->lock);

	/* if we've already got a readlock on the server then we can instantly
	 * grant another readlock, irrespective of whether there are any
	 * pending writelocks */
	if (type == AFS_LOCK_READ &&
	    vnode->flags & (1 << AFS_VNODE_READLOCKED)) {
		_debug("instant readlock");
		ASSERTCMP(vnode->flags &
			  ((1 << AFS_VNODE_LOCKING) |
			   (1 << AFS_VNODE_WRITELOCKED)), ==, 0);
		ASSERT(!list_empty(&vnode->granted_locks));
		goto sharing_existing_lock;
	}

	/* if there's no-one else with a lock on this vnode, then we need to
	 * ask the server for a lock */
	if (list_empty(&vnode->pending_locks) &&
	    list_empty(&vnode->granted_locks)) {
		_debug("not locked");
		ASSERTCMP(vnode->flags &
			  ((1 << AFS_VNODE_LOCKING) |
			   (1 << AFS_VNODE_READLOCKED) |
			   (1 << AFS_VNODE_WRITELOCKED)), ==, 0);
		list_add_tail(&fl->fl_u.afs.link, &vnode->pending_locks);
		set_bit(AFS_VNODE_LOCKING, &vnode->flags);
		spin_unlock(&vnode->lock);

		ret = afs_vnode_set_lock(vnode, key, type);
		clear_bit(AFS_VNODE_LOCKING, &vnode->flags);
		switch (ret) {
		case 0:
			_debug("acquired");
			goto acquired_server_lock;
		case -EWOULDBLOCK:
			_debug("would block");
			spin_lock(&vnode->lock);
			ASSERT(list_empty(&vnode->granted_locks));
			ASSERTCMP(vnode->pending_locks.next, ==,
				  &fl->fl_u.afs.link);
			goto wait;
		default:
			spin_lock(&vnode->lock);
			list_del_init(&fl->fl_u.afs.link);
			spin_unlock(&vnode->lock);
			goto error;
		}
	}

	/* otherwise, we need to wait for a local lock to become available */
	_debug("wait local");
	list_add_tail(&fl->fl_u.afs.link, &vnode->pending_locks);
wait:
	if (!(fl->fl_flags & FL_SLEEP)) {
		_debug("noblock");
		ret = -EAGAIN;
		goto abort_attempt;
	}
	spin_unlock(&vnode->lock);

	/* now we need to sleep and wait for the lock manager thread to get the
	 * lock from the server */
	_debug("sleep");
	ret = wait_event_interruptible(fl->fl_wait,
				       fl->fl_u.afs.state <= AFS_LOCK_GRANTED);
	if (fl->fl_u.afs.state <= AFS_LOCK_GRANTED) {
		ret = fl->fl_u.afs.state;
		if (ret < 0)
			goto error;
		spin_lock(&vnode->lock);
		goto given_lock;
	}

	/* we were interrupted, but someone may still be in the throes of
	 * giving us the lock */
	_debug("intr");
	ASSERTCMP(ret, ==, -ERESTARTSYS);

	spin_lock(&vnode->lock);
	if (fl->fl_u.afs.state <= AFS_LOCK_GRANTED) {
		ret = fl->fl_u.afs.state;
		if (ret < 0) {
			spin_unlock(&vnode->lock);
			goto error;
		}
		goto given_lock;
	}

abort_attempt:
	/* we aren't going to get the lock, either because we're unwilling to
	 * wait, or because some signal happened */
	_debug("abort");
	if (list_empty(&vnode->granted_locks) &&
	    vnode->pending_locks.next == &fl->fl_u.afs.link) {
		if (vnode->pending_locks.prev != &fl->fl_u.afs.link) {
			/* kick the next pending lock into having a go */
			list_del_init(&fl->fl_u.afs.link);
			afs_lock_may_be_available(vnode);
		}
	} else {
		list_del_init(&fl->fl_u.afs.link);
	}
	spin_unlock(&vnode->lock);
	goto error;

acquired_server_lock:
	/* we've acquired a server lock, but it needs to be renewed after 5
	 * mins */
	spin_lock(&vnode->lock);
	afs_schedule_lock_extension(vnode);
	if (type == AFS_LOCK_READ)
		set_bit(AFS_VNODE_READLOCKED, &vnode->flags);
	else
		set_bit(AFS_VNODE_WRITELOCKED, &vnode->flags);
sharing_existing_lock:
	/* the lock has been granted as far as we're concerned... */
	fl->fl_u.afs.state = AFS_LOCK_GRANTED;
	list_move_tail(&fl->fl_u.afs.link, &vnode->granted_locks);
given_lock:
	/* ... but we do still need to get the VFS's blessing */
	ASSERT(!(vnode->flags & (1 << AFS_VNODE_LOCKING)));
	ASSERT((vnode->flags & ((1 << AFS_VNODE_READLOCKED) |
				(1 << AFS_VNODE_WRITELOCKED))) != 0);
	ret = posix_lock_file(file, fl, NULL);
	if (ret < 0)
		goto vfs_rejected_lock;
	spin_unlock(&vnode->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_vnode_fetch_status(vnode, NULL, key);

error:
	unlock_flocks();
	_leave(" = %d", ret);
	return ret;

vfs_rejected_lock:
	/* the VFS rejected the lock we just obtained, so we have to discard
	 * what we just got */
	_debug("vfs refused %d", ret);
	list_del_init(&fl->fl_u.afs.link);
	if (list_empty(&vnode->granted_locks))
		afs_defer_unlock(vnode, key);
	goto abort_attempt;
}

/*
 * 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(file->f_mapping->host);
	struct key *key = file->private_data;
	int ret;

	_enter("{%x:%u},%u", vnode->fid.vid, vnode->fid.vnode, fl->fl_type);

	/* only whole-file unlocks are supported */
	if (fl->fl_start != 0 || fl->fl_end != OFFSET_MAX)
		return -EINVAL;

	fl->fl_ops = &afs_lock_ops;
	INIT_LIST_HEAD(&fl->fl_u.afs.link);
	fl->fl_u.afs.state = AFS_LOCK_PENDING;

	spin_lock(&vnode->lock);
	ret = posix_lock_file(file, fl, NULL);
	if (ret < 0) {
		spin_unlock(&vnode->lock);
		_leave(" = %d [vfs]", ret);
		return ret;
	}

	/* discard the server lock only if all granted locks are gone */
	if (list_empty(&vnode->granted_locks))
		afs_defer_unlock(vnode, key);
	spin_unlock(&vnode->lock);
	_leave(" = 0");
	return 0;
}

/*
 * 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(file->f_mapping->host);
	struct key *key = file->private_data;
	int ret, lock_count;

	_enter("");

	fl->fl_type = F_UNLCK;

	mutex_lock(&vnode->vfs_inode.i_mutex);

	/* check local lock records first */
	ret = 0;
	posix_test_lock(file, fl);
	if (fl->fl_type == F_UNLCK) {
		/* no local locks; consult the server */
		ret = afs_vnode_fetch_status(vnode, NULL, key);
		if (ret < 0)
			goto error;
		lock_count = vnode->status.lock_count;
		if (lock_count) {
			if (lock_count > 0)
				fl->fl_type = F_RDLCK;
			else
				fl->fl_type = F_WRLCK;
			fl->fl_start = 0;
			fl->fl_end = OFFSET_MAX;
		}
	}

error:
	mutex_unlock(&vnode->vfs_inode.i_mutex);
	_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(file->f_dentry->d_inode);

	_enter("{%x:%u},%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);
	if (fl->fl_type == F_UNLCK)
		return afs_do_unlk(file, fl);
	return afs_do_setlk(file, fl);
}

/*
 * 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(file->f_dentry->d_inode);

	_enter("{%x:%u},%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;

	/* we're simulating flock() locks using posix locks on the server */
	fl->fl_owner = (fl_owner_t) file;
	fl->fl_start = 0;
	fl->fl_end = OFFSET_MAX;

	if (fl->fl_type == F_UNLCK)
		return afs_do_unlk(file, fl);
	return afs_do_setlk(file, fl);
}

/*
 * 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)
{
	_enter("");

	list_add(&new->fl_u.afs.link, &fl->fl_u.afs.link);
}

/*
 * 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)
{
	_enter("");

	list_del_init(&fl->fl_u.afs.link);
}