/* * 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@infradead.org> *          David Howells <dhowells@redhat.com> * */ #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 0unsigned 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){	mod_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);}