[deliverable/linux.git] / fs / afs / callback.c

/*
 * Copyright (c) 2002, 2007 Red Hat, Inc. All rights reserved.
 *
 * This software may be freely redistributed under the terms of the
 * GNU General Public License.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 * Authors: David Woodhouse <dwmw2@cambridge.redhat.com>
 *          David Howells <dhowells@redhat.com>
 *
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/circ_buf.h>
#include "internal.h"

unsigned afs_vnode_update_timeout = 10;

#define afs_breakring_space(server) \
	CIRC_SPACE((server)->cb_break_head, (server)->cb_break_tail,	\
		   ARRAY_SIZE((server)->cb_break))

//static void afs_callback_updater(struct work_struct *);

static struct workqueue_struct *afs_callback_update_worker;

/*
 * allow the fileserver to request callback state (re-)initialisation
 */
void afs_init_callback_state(struct afs_server *server)
{
	struct afs_vnode *vnode;

	_enter("{%p}", server);

	spin_lock(&server->cb_lock);

	/* kill all the promises on record from this server */
	while (!RB_EMPTY_ROOT(&server->cb_promises)) {
		vnode = rb_entry(server->cb_promises.rb_node,
				 struct afs_vnode, cb_promise);
		printk("\nUNPROMISE on %p\n", vnode);
		rb_erase(&vnode->cb_promise, &server->cb_promises);
		vnode->cb_promised = false;
	}

	spin_unlock(&server->cb_lock);
	_leave("");
}

/*
 * handle the data invalidation side of a callback being broken
 */
void afs_broken_callback_work(struct work_struct *work)
{
	struct afs_vnode *vnode =
		container_of(work, struct afs_vnode, cb_broken_work);

	_enter("");

	if (test_bit(AFS_VNODE_DELETED, &vnode->flags))
		return;

	/* we're only interested in dealing with a broken callback on *this*
	 * vnode and only if no-one else has dealt with it yet */
	if (!mutex_trylock(&vnode->cb_broken_lock))
		return; /* someone else is dealing with it */

	if (test_bit(AFS_VNODE_CB_BROKEN, &vnode->flags)) {
		if (S_ISDIR(vnode->vfs_inode.i_mode))
			afs_clear_permits(vnode);

		if (afs_vnode_fetch_status(vnode, NULL, NULL) < 0)
			goto out;

		if (test_bit(AFS_VNODE_DELETED, &vnode->flags))
			goto out;

		/* if the vnode's data version number changed then its contents
		 * are different */
		if (test_and_clear_bit(AFS_VNODE_ZAP_DATA, &vnode->flags)) {
			_debug("zap data");
			invalidate_remote_inode(&vnode->vfs_inode);
		}
	}

out:
	mutex_unlock(&vnode->cb_broken_lock);

	/* avoid the potential race whereby the mutex_trylock() in this
	 * function happens again between the clear_bit() and the
	 * mutex_unlock() */
	if (test_bit(AFS_VNODE_CB_BROKEN, &vnode->flags)) {
		_debug("requeue");
		queue_work(afs_callback_update_worker, &vnode->cb_broken_work);
	}
	_leave("");
}

/*
 * actually break a callback
 */
static void afs_break_callback(struct afs_server *server,
			       struct afs_vnode *vnode)
{
	_enter("");

	set_bit(AFS_VNODE_CB_BROKEN, &vnode->flags);

	if (vnode->cb_promised) {
		spin_lock(&vnode->lock);

		_debug("break callback");

		spin_lock(&server->cb_lock);
		if (vnode->cb_promised) {
			rb_erase(&vnode->cb_promise, &server->cb_promises);
			vnode->cb_promised = false;
		}
		spin_unlock(&server->cb_lock);

		queue_work(afs_callback_update_worker, &vnode->cb_broken_work);
		spin_unlock(&vnode->lock);
	}
}

/*
 * allow the fileserver to explicitly break one callback
 * - happens when
 *   - the backing file is changed
 *   - a lock is released
 */
static void afs_break_one_callback(struct afs_server *server,
				   struct afs_fid *fid)
{
	struct afs_vnode *vnode;
	struct rb_node *p;

	_debug("find");
	spin_lock(&server->fs_lock);
	p = server->fs_vnodes.rb_node;
	while (p) {
		vnode = rb_entry(p, struct afs_vnode, server_rb);
		if (fid->vid < vnode->fid.vid)
			p = p->rb_left;
		else if (fid->vid > vnode->fid.vid)
			p = p->rb_right;
		else if (fid->vnode < vnode->fid.vnode)
			p = p->rb_left;
		else if (fid->vnode > vnode->fid.vnode)
			p = p->rb_right;
		else if (fid->unique < vnode->fid.unique)
			p = p->rb_left;
		else if (fid->unique > vnode->fid.unique)
			p = p->rb_right;
		else
			goto found;
	}

	/* not found so we just ignore it (it may have moved to another
	 * server) */
not_available:
	_debug("not avail");
	spin_unlock(&server->fs_lock);
	_leave("");
	return;

found:
	_debug("found");
	ASSERTCMP(server, ==, vnode->server);

	if (!igrab(AFS_VNODE_TO_I(vnode)))
		goto not_available;
	spin_unlock(&server->fs_lock);

	afs_break_callback(server, vnode);
	iput(&vnode->vfs_inode);
	_leave("");
}

/*
 * allow the fileserver to break callback promises
 */
void afs_break_callbacks(struct afs_server *server, size_t count,
			 struct afs_callback callbacks[])
{
	_enter("%p,%zu,", server, count);

	ASSERT(server != NULL);
	ASSERTCMP(count, <=, AFSCBMAX);

	for (; count > 0; callbacks++, count--) {
		_debug("- Fid { vl=%08x n=%u u=%u }  CB { v=%u x=%u t=%u }",
		       callbacks->fid.vid,
		       callbacks->fid.vnode,
		       callbacks->fid.unique,
		       callbacks->version,
		       callbacks->expiry,
		       callbacks->type
		       );
		afs_break_one_callback(server, &callbacks->fid);
	}

	_leave("");
	return;
}

/*
 * record the callback for breaking
 * - the caller must hold server->cb_lock
 */
static void afs_do_give_up_callback(struct afs_server *server,
				    struct afs_vnode *vnode)
{
	struct afs_callback *cb;

	_enter("%p,%p", server, vnode);

	cb = &server->cb_break[server->cb_break_head];
	cb->fid		= vnode->fid;
	cb->version	= vnode->cb_version;
	cb->expiry	= vnode->cb_expiry;
	cb->type	= vnode->cb_type;
	smp_wmb();
	server->cb_break_head =
		(server->cb_break_head + 1) &
		(ARRAY_SIZE(server->cb_break) - 1);

	/* defer the breaking of callbacks to try and collect as many as
	 * possible to ship in one operation */
	switch (atomic_inc_return(&server->cb_break_n)) {
	case 1 ... AFSCBMAX - 1:
		queue_delayed_work(afs_callback_update_worker,
				   &server->cb_break_work, HZ * 2);
		break;
	case AFSCBMAX:
		afs_flush_callback_breaks(server);
		break;
	default:
		break;
	}

	ASSERT(server->cb_promises.rb_node != NULL);
	rb_erase(&vnode->cb_promise, &server->cb_promises);
	vnode->cb_promised = false;
	_leave("");
}

/*
 * give up the callback registered for a vnode on the file server when the
 * inode is being cleared
 */
void afs_give_up_callback(struct afs_vnode *vnode)
{
	struct afs_server *server = vnode->server;

	DECLARE_WAITQUEUE(myself, current);

	_enter("%d", vnode->cb_promised);

	_debug("GIVE UP INODE %p", &vnode->vfs_inode);

	if (!vnode->cb_promised) {
		_leave(" [not promised]");
		return;
	}

	ASSERT(server != NULL);

	spin_lock(&server->cb_lock);
	if (vnode->cb_promised && afs_breakring_space(server) == 0) {
		add_wait_queue(&server->cb_break_waitq, &myself);
		for (;;) {
			set_current_state(TASK_UNINTERRUPTIBLE);
			if (!vnode->cb_promised ||
			    afs_breakring_space(server) != 0)
				break;
			spin_unlock(&server->cb_lock);
			schedule();
			spin_lock(&server->cb_lock);
		}
		remove_wait_queue(&server->cb_break_waitq, &myself);
		__set_current_state(TASK_RUNNING);
	}

	/* of course, it's always possible for the server to break this vnode's
	 * callback first... */
	if (vnode->cb_promised)
		afs_do_give_up_callback(server, vnode);

	spin_unlock(&server->cb_lock);
	_leave("");
}

/*
 * dispatch a deferred give up callbacks operation
 */
void afs_dispatch_give_up_callbacks(struct work_struct *work)
{
	struct afs_server *server =
		container_of(work, struct afs_server, cb_break_work.work);

	_enter("");

	/* tell the fileserver to discard the callback promises it has
	 * - in the event of ENOMEM or some other error, we just forget that we
	 *   had callbacks entirely, and the server will call us later to break
	 *   them
	 */
	afs_fs_give_up_callbacks(server, &afs_async_call);
}

/*
 * flush the outstanding callback breaks on a server
 */
void afs_flush_callback_breaks(struct afs_server *server)
{
	cancel_delayed_work(&server->cb_break_work);
	queue_delayed_work(afs_callback_update_worker,
			   &server->cb_break_work, 0);
}

#if 0
/*
 * update a bunch of callbacks
 */
static void afs_callback_updater(struct work_struct *work)
{
	struct afs_server *server;
	struct afs_vnode *vnode, *xvnode;
	time_t now;
	long timeout;
	int ret;

	server = container_of(work, struct afs_server, updater);

	_enter("");

	now = get_seconds();

	/* find the first vnode to update */
	spin_lock(&server->cb_lock);
	for (;;) {
		if (RB_EMPTY_ROOT(&server->cb_promises)) {
			spin_unlock(&server->cb_lock);
			_leave(" [nothing]");
			return;
		}

		vnode = rb_entry(rb_first(&server->cb_promises),
				 struct afs_vnode, cb_promise);
		if (atomic_read(&vnode->usage) > 0)
			break;
		rb_erase(&vnode->cb_promise, &server->cb_promises);
		vnode->cb_promised = false;
	}

	timeout = vnode->update_at - now;
	if (timeout > 0) {
		queue_delayed_work(afs_vnode_update_worker,
				   &afs_vnode_update, timeout * HZ);
		spin_unlock(&server->cb_lock);
		_leave(" [nothing]");
		return;
	}

	list_del_init(&vnode->update);
	atomic_inc(&vnode->usage);
	spin_unlock(&server->cb_lock);

	/* we can now perform the update */
	_debug("update %s", vnode->vldb.name);
	vnode->state = AFS_VL_UPDATING;
	vnode->upd_rej_cnt = 0;
	vnode->upd_busy_cnt = 0;

	ret = afs_vnode_update_record(vl, &vldb);
	switch (ret) {
	case 0:
		afs_vnode_apply_update(vl, &vldb);
		vnode->state = AFS_VL_UPDATING;
		break;
	case -ENOMEDIUM:
		vnode->state = AFS_VL_VOLUME_DELETED;
		break;
	default:
		vnode->state = AFS_VL_UNCERTAIN;
		break;
	}

	/* and then reschedule */
	_debug("reschedule");
	vnode->update_at = get_seconds() + afs_vnode_update_timeout;

	spin_lock(&server->cb_lock);

	if (!list_empty(&server->cb_promises)) {
		/* next update in 10 minutes, but wait at least 1 second more
		 * than the newest record already queued so that we don't spam
		 * the VL server suddenly with lots of requests
		 */
		xvnode = list_entry(server->cb_promises.prev,
				    struct afs_vnode, update);
		if (vnode->update_at <= xvnode->update_at)
			vnode->update_at = xvnode->update_at + 1;
		xvnode = list_entry(server->cb_promises.next,
				    struct afs_vnode, update);
		timeout = xvnode->update_at - now;
		if (timeout < 0)
			timeout = 0;
	} else {
		timeout = afs_vnode_update_timeout;
	}

	list_add_tail(&vnode->update, &server->cb_promises);

	_debug("timeout %ld", timeout);
	queue_delayed_work(afs_vnode_update_worker,
			   &afs_vnode_update, timeout * HZ);
	spin_unlock(&server->cb_lock);
	afs_put_vnode(vl);
}
#endif

/*
 * initialise the callback update process
 */
int __init afs_callback_update_init(void)
{
	afs_callback_update_worker =
		create_singlethread_workqueue("kafs_callbackd");
	return afs_callback_update_worker ? 0 : -ENOMEM;
}

/*
 * shut down the callback update process
 */
void __exit afs_callback_update_kill(void)
{
	destroy_workqueue(afs_callback_update_worker);
}
Commit	Line	Data
1da177e4	1	/*
08e0e7c8	2	* Copyright (c) 2002, 2007 Red Hat, Inc. All rights reserved.
1da177e4 LT	3	*
	4	* This software may be freely redistributed under the terms of the
	5	* GNU General Public License.
	6	*
	7	* You should have received a copy of the GNU General Public License
	8	* along with this program; if not, write to the Free Software
	9	* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
	10	*
	11	* Authors: David Woodhouse <dwmw2@cambridge.redhat.com>
	12	* David Howells <dhowells@redhat.com>
	13	*
	14	*/
	15
	16	#include <linux/kernel.h>
	17	#include <linux/module.h>
	18	#include <linux/init.h>
08e0e7c8	19	#include <linux/circ_buf.h>
1da177e4	20	#include "internal.h"
08e0e7c8 DH	21
	22	unsigned afs_vnode_update_timeout = 10;
	23
	24	#define afs_breakring_space(server) \
	25	CIRC_SPACE((server)->cb_break_head, (server)->cb_break_tail, \
	26	ARRAY_SIZE((server)->cb_break))
	27
	28	//static void afs_callback_updater(struct work_struct *);
	29
	30	static struct workqueue_struct *afs_callback_update_worker;
1da177e4	31
1da177e4 LT	32	/*
	33	* allow the fileserver to request callback state (re-)initialisation
	34	*/
08e0e7c8	35	void afs_init_callback_state(struct afs_server *server)
1da177e4	36	{
08e0e7c8	37	struct afs_vnode *vnode;
1da177e4	38
08e0e7c8	39	_enter("{%p}", server);
1da177e4	40
1da177e4 LT	41	spin_lock(&server->cb_lock);
1da177e4 LT	42
08e0e7c8 DH	43	/* kill all the promises on record from this server */
	44	while (!RB_EMPTY_ROOT(&server->cb_promises)) {
	45	vnode = rb_entry(server->cb_promises.rb_node,
	46	struct afs_vnode, cb_promise);
	47	printk("\nUNPROMISE on %p\n", vnode);
	48	rb_erase(&vnode->cb_promise, &server->cb_promises);
	49	vnode->cb_promised = false;
	50	}
1da177e4	51
08e0e7c8 DH	52	spin_unlock(&server->cb_lock);
	53	_leave("");
	54	}
1da177e4	55
08e0e7c8 DH	56	/*
	57	* handle the data invalidation side of a callback being broken
	58	*/
	59	void afs_broken_callback_work(struct work_struct *work)
	60	{
	61	struct afs_vnode *vnode =
	62	container_of(work, struct afs_vnode, cb_broken_work);
1da177e4	63
08e0e7c8	64	_enter("");
1da177e4	65
08e0e7c8 DH	66	if (test_bit(AFS_VNODE_DELETED, &vnode->flags))
08e0e7c8 DH	67	return;
1da177e4	68
08e0e7c8 DH	69	/* we're only interested in dealing with a broken callback on this
	70	* vnode and only if no-one else has dealt with it yet */
	71	if (!mutex_trylock(&vnode->cb_broken_lock))
	72	return; /* someone else is dealing with it */
1da177e4	73
08e0e7c8	74	if (test_bit(AFS_VNODE_CB_BROKEN, &vnode->flags)) {
00d3b7a4 DH	75	if (S_ISDIR(vnode->vfs_inode.i_mode))
	76	afs_clear_permits(vnode);
	77
	78	if (afs_vnode_fetch_status(vnode, NULL, NULL) < 0)
08e0e7c8	79	goto out;
1da177e4	80
08e0e7c8 DH	81	if (test_bit(AFS_VNODE_DELETED, &vnode->flags))
08e0e7c8 DH	82	goto out;
1da177e4	83
08e0e7c8 DH	84	/* if the vnode's data version number changed then its contents
	85	* are different */
	86	if (test_and_clear_bit(AFS_VNODE_ZAP_DATA, &vnode->flags)) {
	87	_debug("zap data");
	88	invalidate_remote_inode(&vnode->vfs_inode);
1da177e4 LT	89	}
	90	}
	91
08e0e7c8 DH	92	out:
08e0e7c8 DH	93	mutex_unlock(&vnode->cb_broken_lock);
1da177e4	94
08e0e7c8 DH	95	/* avoid the potential race whereby the mutex_trylock() in this
	96	* function happens again between the clear_bit() and the
	97	* mutex_unlock() */
	98	if (test_bit(AFS_VNODE_CB_BROKEN, &vnode->flags)) {
	99	_debug("requeue");
	100	queue_work(afs_callback_update_worker, &vnode->cb_broken_work);
	101	}
	102	_leave("");
	103	}
	104
	105	/*
	106	* actually break a callback
	107	*/
	108	static void afs_break_callback(struct afs_server *server,
	109	struct afs_vnode *vnode)
	110	{
	111	_enter("");
	112
	113	set_bit(AFS_VNODE_CB_BROKEN, &vnode->flags);
	114
	115	if (vnode->cb_promised) {
	116	spin_lock(&vnode->lock);
	117
	118	_debug("break callback");
	119
	120	spin_lock(&server->cb_lock);
	121	if (vnode->cb_promised) {
	122	rb_erase(&vnode->cb_promise, &server->cb_promises);
	123	vnode->cb_promised = false;
	124	}
	125	spin_unlock(&server->cb_lock);
	126
	127	queue_work(afs_callback_update_worker, &vnode->cb_broken_work);
	128	spin_unlock(&vnode->lock);
	129	}
	130	}
	131
	132	/*
	133	* allow the fileserver to explicitly break one callback
	134	* - happens when
	135	* - the backing file is changed
	136	* - a lock is released
	137	*/
	138	static void afs_break_one_callback(struct afs_server *server,
	139	struct afs_fid *fid)
	140	{
	141	struct afs_vnode *vnode;
	142	struct rb_node *p;
	143
	144	_debug("find");
	145	spin_lock(&server->fs_lock);
	146	p = server->fs_vnodes.rb_node;
	147	while (p) {
	148	vnode = rb_entry(p, struct afs_vnode, server_rb);
	149	if (fid->vid < vnode->fid.vid)
	150	p = p->rb_left;
	151	else if (fid->vid > vnode->fid.vid)
	152	p = p->rb_right;
	153	else if (fid->vnode < vnode->fid.vnode)
	154	p = p->rb_left;
	155	else if (fid->vnode > vnode->fid.vnode)
	156	p = p->rb_right;
	157	else if (fid->unique < vnode->fid.unique)
	158	p = p->rb_left;
159	else if (fid->unique > vnode->fid.unique)
160	p = p->rb_right;
161	else
162	goto found;
163	}
164
165	/* not found so we just ignore it (it may have moved to another
166	* server) */
167	not_available:
168	_debug("not avail");
169	spin_unlock(&server->fs_lock);
170	_leave("");
171	return;
172
173	found:
174	_debug("found");
175	ASSERTCMP(server, ==, vnode->server);
176
177	if (!igrab(AFS_VNODE_TO_I(vnode)))
178	goto not_available;
179	spin_unlock(&server->fs_lock);
180
181	afs_break_callback(server, vnode);
182	iput(&vnode->vfs_inode);
183	_leave("");
ec26815a	184	}
1da177e4	185
1da177e4 LT	186	/*
	187	* allow the fileserver to break callback promises
	188	*/
08e0e7c8 DH	189	void afs_break_callbacks(struct afs_server *server, size_t count,
08e0e7c8 DH	190	struct afs_callback callbacks[])
1da177e4	191	{
08e0e7c8	192	_enter("%p,%zu,", server, count);
1da177e4	193
08e0e7c8 DH	194	ASSERT(server != NULL);
08e0e7c8 DH	195	ASSERTCMP(count, <=, AFSCBMAX);
1da177e4	196
08e0e7c8	197	for (; count > 0; callbacks++, count--) {
1da177e4 LT	198	_debug("- Fid { vl=%08x n=%u u=%u } CB { v=%u x=%u t=%u }",
	199	callbacks->fid.vid,
	200	callbacks->fid.vnode,
	201	callbacks->fid.unique,
	202	callbacks->version,
	203	callbacks->expiry,
	204	callbacks->type
	205	);
08e0e7c8 DH	206	afs_break_one_callback(server, &callbacks->fid);
	207	}
	208
	209	_leave("");
	210	return;
	211	}
1da177e4	212
08e0e7c8 DH	213	/*
	214	* record the callback for breaking
	215	* - the caller must hold server->cb_lock
	216	*/
	217	static void afs_do_give_up_callback(struct afs_server *server,
	218	struct afs_vnode *vnode)
	219	{
	220	struct afs_callback *cb;
1da177e4	221
08e0e7c8	222	_enter("%p,%p", server, vnode);
1da177e4	223
08e0e7c8 DH	224	cb = &server->cb_break[server->cb_break_head];
	225	cb->fid = vnode->fid;
	226	cb->version = vnode->cb_version;
	227	cb->expiry = vnode->cb_expiry;
	228	cb->type = vnode->cb_type;
	229	smp_wmb();
	230	server->cb_break_head =
	231	(server->cb_break_head + 1) &
	232	(ARRAY_SIZE(server->cb_break) - 1);
1da177e4	233
08e0e7c8 DH	234	/* defer the breaking of callbacks to try and collect as many as
	235	* possible to ship in one operation */
	236	switch (atomic_inc_return(&server->cb_break_n)) {
	237	case 1 ... AFSCBMAX - 1:
	238	queue_delayed_work(afs_callback_update_worker,
	239	&server->cb_break_work, HZ * 2);
	240	break;
	241	case AFSCBMAX:
	242	afs_flush_callback_breaks(server);
	243	break;
	244	default:
	245	break;
	246	}
	247
	248	ASSERT(server->cb_promises.rb_node != NULL);
	249	rb_erase(&vnode->cb_promise, &server->cb_promises);
	250	vnode->cb_promised = false;
	251	_leave("");
	252	}
	253
	254	/*
	255	* give up the callback registered for a vnode on the file server when the
	256	* inode is being cleared
	257	*/
	258	void afs_give_up_callback(struct afs_vnode *vnode)
	259	{
	260	struct afs_server *server = vnode->server;
	261
	262	DECLARE_WAITQUEUE(myself, current);
	263
	264	_enter("%d", vnode->cb_promised);
	265
	266	_debug("GIVE UP INODE %p", &vnode->vfs_inode);
	267
	268	if (!vnode->cb_promised) {
	269	_leave(" [not promised]");
	270	return;
	271	}
	272
	273	ASSERT(server != NULL);
	274
	275	spin_lock(&server->cb_lock);
	276	if (vnode->cb_promised && afs_breakring_space(server) == 0) {
	277	add_wait_queue(&server->cb_break_waitq, &myself);
	278	for (;;) {
	279	set_current_state(TASK_UNINTERRUPTIBLE);
	280	if (!vnode->cb_promised \|\|
	281	afs_breakring_space(server) != 0)
	282	break;
	283	spin_unlock(&server->cb_lock);
	284	schedule();
	285	spin_lock(&server->cb_lock);
1da177e4	286	}
08e0e7c8 DH	287	remove_wait_queue(&server->cb_break_waitq, &myself);
	288	__set_current_state(TASK_RUNNING);
	289	}
	290
	291	/* of course, it's always possible for the server to break this vnode's
	292	* callback first... */
	293	if (vnode->cb_promised)
	294	afs_do_give_up_callback(server, vnode);
	295
	296	spin_unlock(&server->cb_lock);
	297	_leave("");
	298	}
	299
	300	/*
	301	* dispatch a deferred give up callbacks operation
	302	*/
	303	void afs_dispatch_give_up_callbacks(struct work_struct *work)
	304	{
	305	struct afs_server *server =
	306	container_of(work, struct afs_server, cb_break_work.work);
	307
	308	_enter("");
	309
	310	/* tell the fileserver to discard the callback promises it has
	311	* - in the event of ENOMEM or some other error, we just forget that we
	312	* had callbacks entirely, and the server will call us later to break
	313	* them
	314	*/
	315	afs_fs_give_up_callbacks(server, &afs_async_call);
	316	}
	317
	318	/*
	319	* flush the outstanding callback breaks on a server
	320	*/
	321	void afs_flush_callback_breaks(struct afs_server *server)
	322	{
	323	cancel_delayed_work(&server->cb_break_work);
	324	queue_delayed_work(afs_callback_update_worker,
	325	&server->cb_break_work, 0);
	326	}
	327
	328	#if 0
	329	/*
	330	* update a bunch of callbacks
	331	*/
	332	static void afs_callback_updater(struct work_struct *work)
	333	{
	334	struct afs_server *server;
	335	struct afs_vnode vnode, xvnode;
	336	time_t now;
	337	long timeout;
	338	int ret;
	339
	340	server = container_of(work, struct afs_server, updater);
	341
	342	_enter("");
1da177e4	343
08e0e7c8 DH	344	now = get_seconds();
	345
	346	/* find the first vnode to update */
	347	spin_lock(&server->cb_lock);
	348	for (;;) {
	349	if (RB_EMPTY_ROOT(&server->cb_promises)) {
	350	spin_unlock(&server->cb_lock);
	351	_leave(" [nothing]");
	352	return;
1da177e4	353	}
08e0e7c8 DH	354
	355	vnode = rb_entry(rb_first(&server->cb_promises),
	356	struct afs_vnode, cb_promise);
	357	if (atomic_read(&vnode->usage) > 0)
	358	break;
	359	rb_erase(&vnode->cb_promise, &server->cb_promises);
	360	vnode->cb_promised = false;
	361	}
	362
	363	timeout = vnode->update_at - now;
	364	if (timeout > 0) {
	365	queue_delayed_work(afs_vnode_update_worker,
	366	&afs_vnode_update, timeout * HZ);
	367	spin_unlock(&server->cb_lock);
	368	_leave(" [nothing]");
	369	return;
	370	}
	371
	372	list_del_init(&vnode->update);
	373	atomic_inc(&vnode->usage);
	374	spin_unlock(&server->cb_lock);
	375
	376	/* we can now perform the update */
	377	_debug("update %s", vnode->vldb.name);
	378	vnode->state = AFS_VL_UPDATING;
	379	vnode->upd_rej_cnt = 0;
	380	vnode->upd_busy_cnt = 0;
	381
	382	ret = afs_vnode_update_record(vl, &vldb);
	383	switch (ret) {
	384	case 0:
	385	afs_vnode_apply_update(vl, &vldb);
	386	vnode->state = AFS_VL_UPDATING;
	387	break;
	388	case -ENOMEDIUM:
	389	vnode->state = AFS_VL_VOLUME_DELETED;
	390	break;
	391	default:
	392	vnode->state = AFS_VL_UNCERTAIN;
	393	break;
	394	}
	395
	396	/* and then reschedule */
	397	_debug("reschedule");
	398	vnode->update_at = get_seconds() + afs_vnode_update_timeout;
	399
	400	spin_lock(&server->cb_lock);
	401
	402	if (!list_empty(&server->cb_promises)) {
	403	/* next update in 10 minutes, but wait at least 1 second more
	404	* than the newest record already queued so that we don't spam
	405	* the VL server suddenly with lots of requests
	406	*/
	407	xvnode = list_entry(server->cb_promises.prev,
	408	struct afs_vnode, update);
	409	if (vnode->update_at <= xvnode->update_at)
	410	vnode->update_at = xvnode->update_at + 1;
	411	xvnode = list_entry(server->cb_promises.next,
	412	struct afs_vnode, update);
	413	timeout = xvnode->update_at - now;
	414	if (timeout < 0)
	415	timeout = 0;
	416	} else {
	417	timeout = afs_vnode_update_timeout;
1da177e4 LT	418	}
1da177e4 LT	419
08e0e7c8 DH	420	list_add_tail(&vnode->update, &server->cb_promises);
	421
	422	_debug("timeout %ld", timeout);
	423	queue_delayed_work(afs_vnode_update_worker,
	424	&afs_vnode_update, timeout * HZ);
	425	spin_unlock(&server->cb_lock);
	426	afs_put_vnode(vl);
	427	}
	428	#endif
	429
	430	/*
	431	* initialise the callback update process
	432	*/
	433	int __init afs_callback_update_init(void)
	434	{
	435	afs_callback_update_worker =
	436	create_singlethread_workqueue("kafs_callbackd");
	437	return afs_callback_update_worker ? 0 : -ENOMEM;
ec26815a	438	}
1da177e4	439
1da177e4	440	/*
08e0e7c8	441	* shut down the callback update process
1da177e4	442	*/
08e0e7c8	443	void __exit afs_callback_update_kill(void)
1da177e4	444	{
08e0e7c8	445	destroy_workqueue(afs_callback_update_worker);
ec26815a	446	}