2 * Copyright (c) 2002, 2007 Red Hat, Inc. All rights reserved.
4 * This software may be freely redistributed under the terms of the
5 * GNU General Public License.
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.
11 * Authors: David Woodhouse <dwmw2@infradead.org>
12 * David Howells <dhowells@redhat.com>
16 #include <linux/kernel.h>
17 #include <linux/module.h>
18 #include <linux/init.h>
19 #include <linux/circ_buf.h>
20 #include <linux/sched.h>
24 unsigned afs_vnode_update_timeout
= 10;
27 #define afs_breakring_space(server) \
28 CIRC_SPACE((server)->cb_break_head, (server)->cb_break_tail, \
29 ARRAY_SIZE((server)->cb_break))
31 //static void afs_callback_updater(struct work_struct *);
33 static struct workqueue_struct
*afs_callback_update_worker
;
36 * allow the fileserver to request callback state (re-)initialisation
38 void afs_init_callback_state(struct afs_server
*server
)
40 struct afs_vnode
*vnode
;
42 _enter("{%p}", server
);
44 spin_lock(&server
->cb_lock
);
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
);
50 _debug("UNPROMISE { vid=%x:%u uq=%u}",
51 vnode
->fid
.vid
, vnode
->fid
.vnode
, vnode
->fid
.unique
);
52 rb_erase(&vnode
->cb_promise
, &server
->cb_promises
);
53 vnode
->cb_promised
= false;
56 spin_unlock(&server
->cb_lock
);
61 * handle the data invalidation side of a callback being broken
63 void afs_broken_callback_work(struct work_struct
*work
)
65 struct afs_vnode
*vnode
=
66 container_of(work
, struct afs_vnode
, cb_broken_work
);
70 if (test_bit(AFS_VNODE_DELETED
, &vnode
->flags
))
73 /* we're only interested in dealing with a broken callback on *this*
74 * vnode and only if no-one else has dealt with it yet */
75 if (!mutex_trylock(&vnode
->validate_lock
))
76 return; /* someone else is dealing with it */
78 if (test_bit(AFS_VNODE_CB_BROKEN
, &vnode
->flags
)) {
79 if (S_ISDIR(vnode
->vfs_inode
.i_mode
))
80 afs_clear_permits(vnode
);
82 if (afs_vnode_fetch_status(vnode
, NULL
, NULL
) < 0)
85 if (test_bit(AFS_VNODE_DELETED
, &vnode
->flags
))
88 /* if the vnode's data version number changed then its contents
90 if (test_and_clear_bit(AFS_VNODE_ZAP_DATA
, &vnode
->flags
))
95 mutex_unlock(&vnode
->validate_lock
);
97 /* avoid the potential race whereby the mutex_trylock() in this
98 * function happens again between the clear_bit() and the
100 if (test_bit(AFS_VNODE_CB_BROKEN
, &vnode
->flags
)) {
102 queue_work(afs_callback_update_worker
, &vnode
->cb_broken_work
);
108 * actually break a callback
110 static void afs_break_callback(struct afs_server
*server
,
111 struct afs_vnode
*vnode
)
115 set_bit(AFS_VNODE_CB_BROKEN
, &vnode
->flags
);
117 if (vnode
->cb_promised
) {
118 spin_lock(&vnode
->lock
);
120 _debug("break callback");
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;
127 spin_unlock(&server
->cb_lock
);
129 queue_work(afs_callback_update_worker
, &vnode
->cb_broken_work
);
130 if (list_empty(&vnode
->granted_locks
) &&
131 !list_empty(&vnode
->pending_locks
))
132 afs_lock_may_be_available(vnode
);
133 spin_unlock(&vnode
->lock
);
138 * allow the fileserver to explicitly break one callback
140 * - the backing file is changed
141 * - a lock is released
143 static void afs_break_one_callback(struct afs_server
*server
,
146 struct afs_vnode
*vnode
;
150 spin_lock(&server
->fs_lock
);
151 p
= server
->fs_vnodes
.rb_node
;
153 vnode
= rb_entry(p
, struct afs_vnode
, server_rb
);
154 if (fid
->vid
< vnode
->fid
.vid
)
156 else if (fid
->vid
> vnode
->fid
.vid
)
158 else if (fid
->vnode
< vnode
->fid
.vnode
)
160 else if (fid
->vnode
> vnode
->fid
.vnode
)
162 else if (fid
->unique
< vnode
->fid
.unique
)
164 else if (fid
->unique
> vnode
->fid
.unique
)
170 /* not found so we just ignore it (it may have moved to another
174 spin_unlock(&server
->fs_lock
);
180 ASSERTCMP(server
, ==, vnode
->server
);
182 if (!igrab(AFS_VNODE_TO_I(vnode
)))
184 spin_unlock(&server
->fs_lock
);
186 afs_break_callback(server
, vnode
);
187 iput(&vnode
->vfs_inode
);
192 * allow the fileserver to break callback promises
194 void afs_break_callbacks(struct afs_server
*server
, size_t count
,
195 struct afs_callback callbacks
[])
197 _enter("%p,%zu,", server
, count
);
199 ASSERT(server
!= NULL
);
200 ASSERTCMP(count
, <=, AFSCBMAX
);
202 for (; count
> 0; callbacks
++, count
--) {
203 _debug("- Fid { vl=%08x n=%u u=%u } CB { v=%u x=%u t=%u }",
205 callbacks
->fid
.vnode
,
206 callbacks
->fid
.unique
,
211 afs_break_one_callback(server
, &callbacks
->fid
);
219 * record the callback for breaking
220 * - the caller must hold server->cb_lock
222 static void afs_do_give_up_callback(struct afs_server
*server
,
223 struct afs_vnode
*vnode
)
225 struct afs_callback
*cb
;
227 _enter("%p,%p", server
, vnode
);
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
;
235 server
->cb_break_head
=
236 (server
->cb_break_head
+ 1) &
237 (ARRAY_SIZE(server
->cb_break
) - 1);
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);
247 afs_flush_callback_breaks(server
);
253 ASSERT(server
->cb_promises
.rb_node
!= NULL
);
254 rb_erase(&vnode
->cb_promise
, &server
->cb_promises
);
255 vnode
->cb_promised
= false;
260 * discard the callback on a deleted item
262 void afs_discard_callback_on_delete(struct afs_vnode
*vnode
)
264 struct afs_server
*server
= vnode
->server
;
266 _enter("%d", vnode
->cb_promised
);
268 if (!vnode
->cb_promised
) {
269 _leave(" [not promised]");
273 ASSERT(server
!= NULL
);
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;
281 spin_unlock(&server
->cb_lock
);
286 * give up the callback registered for a vnode on the file server when the
287 * inode is being cleared
289 void afs_give_up_callback(struct afs_vnode
*vnode
)
291 struct afs_server
*server
= vnode
->server
;
293 DECLARE_WAITQUEUE(myself
, current
);
295 _enter("%d", vnode
->cb_promised
);
297 _debug("GIVE UP INODE %p", &vnode
->vfs_inode
);
299 if (!vnode
->cb_promised
) {
300 _leave(" [not promised]");
304 ASSERT(server
!= NULL
);
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
);
310 set_current_state(TASK_UNINTERRUPTIBLE
);
311 if (!vnode
->cb_promised
||
312 afs_breakring_space(server
) != 0)
314 spin_unlock(&server
->cb_lock
);
316 spin_lock(&server
->cb_lock
);
318 remove_wait_queue(&server
->cb_break_waitq
, &myself
);
319 __set_current_state(TASK_RUNNING
);
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
);
327 spin_unlock(&server
->cb_lock
);
332 * dispatch a deferred give up callbacks operation
334 void afs_dispatch_give_up_callbacks(struct work_struct
*work
)
336 struct afs_server
*server
=
337 container_of(work
, struct afs_server
, cb_break_work
.work
);
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
346 afs_fs_give_up_callbacks(server
, &afs_async_call
);
350 * flush the outstanding callback breaks on a server
352 void afs_flush_callback_breaks(struct afs_server
*server
)
354 cancel_delayed_work(&server
->cb_break_work
);
355 queue_delayed_work(afs_callback_update_worker
,
356 &server
->cb_break_work
, 0);
361 * update a bunch of callbacks
363 static void afs_callback_updater(struct work_struct
*work
)
365 struct afs_server
*server
;
366 struct afs_vnode
*vnode
, *xvnode
;
371 server
= container_of(work
, struct afs_server
, updater
);
377 /* find the first vnode to update */
378 spin_lock(&server
->cb_lock
);
380 if (RB_EMPTY_ROOT(&server
->cb_promises
)) {
381 spin_unlock(&server
->cb_lock
);
382 _leave(" [nothing]");
386 vnode
= rb_entry(rb_first(&server
->cb_promises
),
387 struct afs_vnode
, cb_promise
);
388 if (atomic_read(&vnode
->usage
) > 0)
390 rb_erase(&vnode
->cb_promise
, &server
->cb_promises
);
391 vnode
->cb_promised
= false;
394 timeout
= vnode
->update_at
- now
;
396 queue_delayed_work(afs_vnode_update_worker
,
397 &afs_vnode_update
, timeout
* HZ
);
398 spin_unlock(&server
->cb_lock
);
399 _leave(" [nothing]");
403 list_del_init(&vnode
->update
);
404 atomic_inc(&vnode
->usage
);
405 spin_unlock(&server
->cb_lock
);
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;
413 ret
= afs_vnode_update_record(vl
, &vldb
);
416 afs_vnode_apply_update(vl
, &vldb
);
417 vnode
->state
= AFS_VL_UPDATING
;
420 vnode
->state
= AFS_VL_VOLUME_DELETED
;
423 vnode
->state
= AFS_VL_UNCERTAIN
;
427 /* and then reschedule */
428 _debug("reschedule");
429 vnode
->update_at
= get_seconds() + afs_vnode_update_timeout
;
431 spin_lock(&server
->cb_lock
);
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
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
;
448 timeout
= afs_vnode_update_timeout
;
451 list_add_tail(&vnode
->update
, &server
->cb_promises
);
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
);
462 * initialise the callback update process
464 int __init
afs_callback_update_init(void)
466 afs_callback_update_worker
=
467 create_singlethread_workqueue("kafs_callbackd");
468 return afs_callback_update_worker
? 0 : -ENOMEM
;
472 * shut down the callback update process
474 void afs_callback_update_kill(void)
476 destroy_workqueue(afs_callback_update_worker
);