[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 <[email protected]>
 *          David Howells <[email protected]>
 *
 */

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

#if 0
unsigned afs_vnode_update_timeout = 10;
#endif  /*  0  */

#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);
		_debug("UNPROMISE { vid=%x:%u uq=%u}",
		       vnode->fid.vid, vnode->fid.vnode, vnode->fid.unique);
		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->validate_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))
			afs_zap_data(vnode);
	}

out:
	mutex_unlock(&vnode->validate_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);
		if (list_empty(&vnode->granted_locks) &&
		    !list_empty(&vnode->pending_locks))
			afs_lock_may_be_available(vnode);
		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("");
}

/*
 * discard the callback on a deleted item
 */
void afs_discard_callback_on_delete(struct afs_vnode *vnode)
{
	struct afs_server *server = vnode->server;

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

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

	ASSERT(server != NULL);

	spin_lock(&server->cb_lock);
	if (vnode->cb_promised) {
		ASSERT(server->cb_promises.rb_node != NULL);
		rb_erase(&vnode->cb_promise, &server->cb_promises);
		vnode->cb_promised = false;
	}
	spin_unlock(&server->cb_lock);
	_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 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	*
44d1b980	11	* Authors: David Woodhouse <[email protected]>
1da177e4 LT	12	* David Howells <[email protected]>
	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>
e8edc6e0	20	#include <linux/sched.h>
1da177e4	21	#include "internal.h"
08e0e7c8	22
c1206a2c	23	#if 0
08e0e7c8	24	unsigned afs_vnode_update_timeout = 10;
c1206a2c	25	#endif /* 0 */
08e0e7c8 DH	26
	27	#define afs_breakring_space(server) \
	28	CIRC_SPACE((server)->cb_break_head, (server)->cb_break_tail, \
	29	ARRAY_SIZE((server)->cb_break))
	30
	31	//static void afs_callback_updater(struct work_struct *);
	32
	33	static struct workqueue_struct *afs_callback_update_worker;
1da177e4	34
1da177e4 LT	35	/*
	36	* allow the fileserver to request callback state (re-)initialisation
	37	*/
08e0e7c8	38	void afs_init_callback_state(struct afs_server *server)
1da177e4	39	{
08e0e7c8	40	struct afs_vnode *vnode;
1da177e4	41
08e0e7c8	42	_enter("{%p}", server);
1da177e4	43
1da177e4 LT	44	spin_lock(&server->cb_lock);
1da177e4 LT	45
08e0e7c8 DH	46	/* kill all the promises on record from this server */
	47	while (!RB_EMPTY_ROOT(&server->cb_promises)) {
	48	vnode = rb_entry(server->cb_promises.rb_node,
	49	struct afs_vnode, cb_promise);
416351f2	50	_debug("UNPROMISE { vid=%x:%u uq=%u}",
260a9803	51	vnode->fid.vid, vnode->fid.vnode, vnode->fid.unique);
08e0e7c8 DH	52	rb_erase(&vnode->cb_promise, &server->cb_promises);
	53	vnode->cb_promised = false;
	54	}
1da177e4	55
08e0e7c8 DH	56	spin_unlock(&server->cb_lock);
	57	_leave("");
	58	}
1da177e4	59
08e0e7c8 DH	60	/*
	61	* handle the data invalidation side of a callback being broken
	62	*/
	63	void afs_broken_callback_work(struct work_struct *work)
	64	{
	65	struct afs_vnode *vnode =
	66	container_of(work, struct afs_vnode, cb_broken_work);
1da177e4	67
08e0e7c8	68	_enter("");
1da177e4	69
08e0e7c8 DH	70	if (test_bit(AFS_VNODE_DELETED, &vnode->flags))
08e0e7c8 DH	71	return;
1da177e4	72
08e0e7c8 DH	73	/* we're only interested in dealing with a broken callback on this
08e0e7c8 DH	74	* vnode and only if no-one else has dealt with it yet */
260a9803	75	if (!mutex_trylock(&vnode->validate_lock))
08e0e7c8	76	return; /* someone else is dealing with it */
1da177e4	77
08e0e7c8	78	if (test_bit(AFS_VNODE_CB_BROKEN, &vnode->flags)) {
00d3b7a4 DH	79	if (S_ISDIR(vnode->vfs_inode.i_mode))
	80	afs_clear_permits(vnode);
	81
	82	if (afs_vnode_fetch_status(vnode, NULL, NULL) < 0)
08e0e7c8	83	goto out;
1da177e4	84
08e0e7c8 DH	85	if (test_bit(AFS_VNODE_DELETED, &vnode->flags))
08e0e7c8 DH	86	goto out;
1da177e4	87
08e0e7c8 DH	88	/* if the vnode's data version number changed then its contents
08e0e7c8 DH	89	* are different */
416351f2 DH	90	if (test_and_clear_bit(AFS_VNODE_ZAP_DATA, &vnode->flags))
416351f2 DH	91	afs_zap_data(vnode);
1da177e4 LT	92	}
1da177e4 LT	93
08e0e7c8	94	out:
260a9803	95	mutex_unlock(&vnode->validate_lock);
1da177e4	96
08e0e7c8 DH	97	/* avoid the potential race whereby the mutex_trylock() in this
	98	* function happens again between the clear_bit() and the
	99	* mutex_unlock() */
	100	if (test_bit(AFS_VNODE_CB_BROKEN, &vnode->flags)) {
	101	_debug("requeue");
	102	queue_work(afs_callback_update_worker, &vnode->cb_broken_work);
	103	}
	104	_leave("");
	105	}
	106
	107	/*
	108	* actually break a callback
	109	*/
	110	static void afs_break_callback(struct afs_server *server,
	111	struct afs_vnode *vnode)
	112	{
	113	_enter("");
	114
	115	set_bit(AFS_VNODE_CB_BROKEN, &vnode->flags);
	116
	117	if (vnode->cb_promised) {
	118	spin_lock(&vnode->lock);
	119
	120	_debug("break callback");
	121
	122	spin_lock(&server->cb_lock);
	123	if (vnode->cb_promised) {
	124	rb_erase(&vnode->cb_promise, &server->cb_promises);
	125	vnode->cb_promised = false;
	126	}
	127	spin_unlock(&server->cb_lock);
	128
	129	queue_work(afs_callback_update_worker, &vnode->cb_broken_work);
e8d6c554 DH	130	if (list_empty(&vnode->granted_locks) &&
	131	!list_empty(&vnode->pending_locks))
	132	afs_lock_may_be_available(vnode);
08e0e7c8 DH	133	spin_unlock(&vnode->lock);
	134	}
	135	}
	136
	137	/*
	138	* allow the fileserver to explicitly break one callback
	139	* - happens when
	140	* - the backing file is changed
	141	* - a lock is released
	142	*/
	143	static void afs_break_one_callback(struct afs_server *server,
	144	struct afs_fid *fid)
	145	{
	146	struct afs_vnode *vnode;
	147	struct rb_node *p;
	148
	149	_debug("find");
	150	spin_lock(&server->fs_lock);
	151	p = server->fs_vnodes.rb_node;
	152	while (p) {
	153	vnode = rb_entry(p, struct afs_vnode, server_rb);
	154	if (fid->vid < vnode->fid.vid)
	155	p = p->rb_left;
	156	else if (fid->vid > vnode->fid.vid)
	157	p = p->rb_right;
	158	else if (fid->vnode < vnode->fid.vnode)
	159	p = p->rb_left;
	160	else if (fid->vnode > vnode->fid.vnode)
	161	p = p->rb_right;
	162	else if (fid->unique < vnode->fid.unique)
	163	p = p->rb_left;
	164	else if (fid->unique > vnode->fid.unique)
	165	p = p->rb_right;
	166	else
	167	goto found;
	168	}
	169
	170	/* not found so we just ignore it (it may have moved to another
	171	* server) */
	172	not_available:
	173	_debug("not avail");
	174	spin_unlock(&server->fs_lock);
	175	_leave("");
	176	return;
	177
	178	found:
	179	_debug("found");
	180	ASSERTCMP(server, ==, vnode->server);
	181
	182	if (!igrab(AFS_VNODE_TO_I(vnode)))
	183	goto not_available;
	184	spin_unlock(&server->fs_lock);
	185
	186	afs_break_callback(server, vnode);
	187	iput(&vnode->vfs_inode);
	188	_leave("");
ec26815a	189	}
1da177e4	190
1da177e4 LT	191	/*
	192	* allow the fileserver to break callback promises
	193	*/
08e0e7c8 DH	194	void afs_break_callbacks(struct afs_server *server, size_t count,
08e0e7c8 DH	195	struct afs_callback callbacks[])
1da177e4	196	{
08e0e7c8	197	_enter("%p,%zu,", server, count);
1da177e4	198
08e0e7c8 DH	199	ASSERT(server != NULL);
08e0e7c8 DH	200	ASSERTCMP(count, <=, AFSCBMAX);
1da177e4	201
08e0e7c8	202	for (; count > 0; callbacks++, count--) {
1da177e4 LT	203	_debug("- Fid { vl=%08x n=%u u=%u } CB { v=%u x=%u t=%u }",
	204	callbacks->fid.vid,
	205	callbacks->fid.vnode,
	206	callbacks->fid.unique,
	207	callbacks->version,
	208	callbacks->expiry,
	209	callbacks->type
	210	);
08e0e7c8 DH	211	afs_break_one_callback(server, &callbacks->fid);
	212	}
	213
	214	_leave("");
	215	return;
	216	}
1da177e4	217
08e0e7c8 DH	218	/*
	219	* record the callback for breaking
	220	* - the caller must hold server->cb_lock
	221	*/
	222	static void afs_do_give_up_callback(struct afs_server *server,
	223	struct afs_vnode *vnode)
	224	{
	225	struct afs_callback *cb;
1da177e4	226
08e0e7c8	227	_enter("%p,%p", server, vnode);
1da177e4	228
08e0e7c8 DH	229	cb = &server->cb_break[server->cb_break_head];
	230	cb->fid = vnode->fid;
	231	cb->version = vnode->cb_version;
	232	cb->expiry = vnode->cb_expiry;
	233	cb->type = vnode->cb_type;
	234	smp_wmb();
	235	server->cb_break_head =
	236	(server->cb_break_head + 1) &
	237	(ARRAY_SIZE(server->cb_break) - 1);
1da177e4	238
08e0e7c8 DH	239	/* defer the breaking of callbacks to try and collect as many as
	240	* possible to ship in one operation */
	241	switch (atomic_inc_return(&server->cb_break_n)) {
	242	case 1 ... AFSCBMAX - 1:
	243	queue_delayed_work(afs_callback_update_worker,
	244	&server->cb_break_work, HZ * 2);
	245	break;
	246	case AFSCBMAX:
	247	afs_flush_callback_breaks(server);
	248	break;
	249	default:
	250	break;
	251	}
	252
	253	ASSERT(server->cb_promises.rb_node != NULL);
	254	rb_erase(&vnode->cb_promise, &server->cb_promises);
	255	vnode->cb_promised = false;
	256	_leave("");
	257	}
	258
260a9803 DH	259	/*
	260	* discard the callback on a deleted item
	261	*/
	262	void afs_discard_callback_on_delete(struct afs_vnode *vnode)
	263	{
	264	struct afs_server *server = vnode->server;
	265
	266	_enter("%d", vnode->cb_promised);
	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) {
	277	ASSERT(server->cb_promises.rb_node != NULL);
	278	rb_erase(&vnode->cb_promise, &server->cb_promises);
	279	vnode->cb_promised = false;
	280	}
	281	spin_unlock(&server->cb_lock);
	282	_leave("");
	283	}
	284
08e0e7c8 DH	285	/*
	286	* give up the callback registered for a vnode on the file server when the
	287	* inode is being cleared
	288	*/
	289	void afs_give_up_callback(struct afs_vnode *vnode)
	290	{
	291	struct afs_server *server = vnode->server;
	292
	293	DECLARE_WAITQUEUE(myself, current);
	294
	295	_enter("%d", vnode->cb_promised);
	296
	297	_debug("GIVE UP INODE %p", &vnode->vfs_inode);
	298
	299	if (!vnode->cb_promised) {
	300	_leave(" [not promised]");
	301	return;
	302	}
	303
	304	ASSERT(server != NULL);
	305
	306	spin_lock(&server->cb_lock);
	307	if (vnode->cb_promised && afs_breakring_space(server) == 0) {
	308	add_wait_queue(&server->cb_break_waitq, &myself);
	309	for (;;) {
	310	set_current_state(TASK_UNINTERRUPTIBLE);
	311	if (!vnode->cb_promised \|\|
	312	afs_breakring_space(server) != 0)
	313	break;
	314	spin_unlock(&server->cb_lock);
	315	schedule();
	316	spin_lock(&server->cb_lock);
1da177e4	317	}
08e0e7c8 DH	318	remove_wait_queue(&server->cb_break_waitq, &myself);
	319	__set_current_state(TASK_RUNNING);
	320	}
	321
	322	/* of course, it's always possible for the server to break this vnode's
	323	* callback first... */
	324	if (vnode->cb_promised)
	325	afs_do_give_up_callback(server, vnode);
	326
	327	spin_unlock(&server->cb_lock);
	328	_leave("");
	329	}
	330
	331	/*
	332	* dispatch a deferred give up callbacks operation
	333	*/
	334	void afs_dispatch_give_up_callbacks(struct work_struct *work)
	335	{
	336	struct afs_server *server =
	337	container_of(work, struct afs_server, cb_break_work.work);
	338
	339	_enter("");
	340
	341	/* tell the fileserver to discard the callback promises it has
	342	* - in the event of ENOMEM or some other error, we just forget that we
	343	* had callbacks entirely, and the server will call us later to break
	344	* them
	345	*/
	346	afs_fs_give_up_callbacks(server, &afs_async_call);
	347	}
	348
	349	/*
	350	* flush the outstanding callback breaks on a server
	351	*/
	352	void afs_flush_callback_breaks(struct afs_server *server)
	353	{
	354	cancel_delayed_work(&server->cb_break_work);
	355	queue_delayed_work(afs_callback_update_worker,
	356	&server->cb_break_work, 0);
	357	}
	358
	359	#if 0
	360	/*
	361	* update a bunch of callbacks
	362	*/
	363	static void afs_callback_updater(struct work_struct *work)
	364	{
	365	struct afs_server *server;
	366	struct afs_vnode vnode, xvnode;
	367	time_t now;
	368	long timeout;
	369	int ret;
	370
	371	server = container_of(work, struct afs_server, updater);
	372
	373	_enter("");
1da177e4	374
08e0e7c8 DH	375	now = get_seconds();
	376
	377	/* find the first vnode to update */
	378	spin_lock(&server->cb_lock);
	379	for (;;) {
	380	if (RB_EMPTY_ROOT(&server->cb_promises)) {
	381	spin_unlock(&server->cb_lock);
	382	_leave(" [nothing]");
	383	return;
1da177e4	384	}
08e0e7c8 DH	385
	386	vnode = rb_entry(rb_first(&server->cb_promises),
	387	struct afs_vnode, cb_promise);
	388	if (atomic_read(&vnode->usage) > 0)
	389	break;
	390	rb_erase(&vnode->cb_promise, &server->cb_promises);
	391	vnode->cb_promised = false;
	392	}
	393
	394	timeout = vnode->update_at - now;
	395	if (timeout > 0) {
	396	queue_delayed_work(afs_vnode_update_worker,
	397	&afs_vnode_update, timeout * HZ);
	398	spin_unlock(&server->cb_lock);
	399	_leave(" [nothing]");
	400	return;
	401	}
	402
	403	list_del_init(&vnode->update);
	404	atomic_inc(&vnode->usage);
	405	spin_unlock(&server->cb_lock);
	406
	407	/* we can now perform the update */
	408	_debug("update %s", vnode->vldb.name);
	409	vnode->state = AFS_VL_UPDATING;
	410	vnode->upd_rej_cnt = 0;
	411	vnode->upd_busy_cnt = 0;
	412
	413	ret = afs_vnode_update_record(vl, &vldb);
	414	switch (ret) {
	415	case 0:
	416	afs_vnode_apply_update(vl, &vldb);
	417	vnode->state = AFS_VL_UPDATING;
	418	break;
	419	case -ENOMEDIUM:
	420	vnode->state = AFS_VL_VOLUME_DELETED;
	421	break;
	422	default:
	423	vnode->state = AFS_VL_UNCERTAIN;
	424	break;
	425	}
	426
	427	/* and then reschedule */
	428	_debug("reschedule");
	429	vnode->update_at = get_seconds() + afs_vnode_update_timeout;
	430
	431	spin_lock(&server->cb_lock);
	432
	433	if (!list_empty(&server->cb_promises)) {
	434	/* next update in 10 minutes, but wait at least 1 second more
	435	* than the newest record already queued so that we don't spam
	436	* the VL server suddenly with lots of requests
	437	*/
	438	xvnode = list_entry(server->cb_promises.prev,
	439	struct afs_vnode, update);
	440	if (vnode->update_at <= xvnode->update_at)
	441	vnode->update_at = xvnode->update_at + 1;
	442	xvnode = list_entry(server->cb_promises.next,
	443	struct afs_vnode, update);
	444	timeout = xvnode->update_at - now;
	445	if (timeout < 0)
	446	timeout = 0;
	447	} else {
	448	timeout = afs_vnode_update_timeout;
1da177e4 LT	449	}
1da177e4 LT	450
08e0e7c8 DH	451	list_add_tail(&vnode->update, &server->cb_promises);
	452
	453	_debug("timeout %ld", timeout);
	454	queue_delayed_work(afs_vnode_update_worker,
	455	&afs_vnode_update, timeout * HZ);
	456	spin_unlock(&server->cb_lock);
	457	afs_put_vnode(vl);
	458	}
	459	#endif
	460
	461	/*
	462	* initialise the callback update process
	463	*/
	464	int __init afs_callback_update_init(void)
	465	{
	466	afs_callback_update_worker =
	467	create_singlethread_workqueue("kafs_callbackd");
	468	return afs_callback_update_worker ? 0 : -ENOMEM;
ec26815a	469	}
1da177e4	470
1da177e4	471	/*
08e0e7c8	472	* shut down the callback update process
1da177e4	473	*/
fbb3fcba	474	void afs_callback_update_kill(void)
1da177e4	475	{
08e0e7c8	476	destroy_workqueue(afs_callback_update_worker);
ec26815a	477	}