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@cambridge.redhat.com>
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>
23 unsigned afs_vnode_update_timeout
= 10;
25 #define afs_breakring_space(server) \
26 CIRC_SPACE((server)->cb_break_head, (server)->cb_break_tail, \
27 ARRAY_SIZE((server)->cb_break))
29 //static void afs_callback_updater(struct work_struct *);
31 static struct workqueue_struct
*afs_callback_update_worker
;
34 * allow the fileserver to request callback state (re-)initialisation
36 void afs_init_callback_state(struct afs_server
*server
)
38 struct afs_vnode
*vnode
;
40 _enter("{%p}", server
);
42 spin_lock(&server
->cb_lock
);
44 /* kill all the promises on record from this server */
45 while (!RB_EMPTY_ROOT(&server
->cb_promises
)) {
46 vnode
= rb_entry(server
->cb_promises
.rb_node
,
47 struct afs_vnode
, cb_promise
);
48 _debug("UNPROMISE { vid=%x:%u uq=%u}",
49 vnode
->fid
.vid
, vnode
->fid
.vnode
, vnode
->fid
.unique
);
50 rb_erase(&vnode
->cb_promise
, &server
->cb_promises
);
51 vnode
->cb_promised
= false;
54 spin_unlock(&server
->cb_lock
);
59 * handle the data invalidation side of a callback being broken
61 void afs_broken_callback_work(struct work_struct
*work
)
63 struct afs_vnode
*vnode
=
64 container_of(work
, struct afs_vnode
, cb_broken_work
);
68 if (test_bit(AFS_VNODE_DELETED
, &vnode
->flags
))
71 /* we're only interested in dealing with a broken callback on *this*
72 * vnode and only if no-one else has dealt with it yet */
73 if (!mutex_trylock(&vnode
->validate_lock
))
74 return; /* someone else is dealing with it */
76 if (test_bit(AFS_VNODE_CB_BROKEN
, &vnode
->flags
)) {
77 if (S_ISDIR(vnode
->vfs_inode
.i_mode
))
78 afs_clear_permits(vnode
);
80 if (afs_vnode_fetch_status(vnode
, NULL
, NULL
) < 0)
83 if (test_bit(AFS_VNODE_DELETED
, &vnode
->flags
))
86 /* if the vnode's data version number changed then its contents
88 if (test_and_clear_bit(AFS_VNODE_ZAP_DATA
, &vnode
->flags
))
93 mutex_unlock(&vnode
->validate_lock
);
95 /* avoid the potential race whereby the mutex_trylock() in this
96 * function happens again between the clear_bit() and the
98 if (test_bit(AFS_VNODE_CB_BROKEN
, &vnode
->flags
)) {
100 queue_work(afs_callback_update_worker
, &vnode
->cb_broken_work
);
106 * actually break a callback
108 static void afs_break_callback(struct afs_server
*server
,
109 struct afs_vnode
*vnode
)
113 set_bit(AFS_VNODE_CB_BROKEN
, &vnode
->flags
);
115 if (vnode
->cb_promised
) {
116 spin_lock(&vnode
->lock
);
118 _debug("break callback");
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;
125 spin_unlock(&server
->cb_lock
);
127 queue_work(afs_callback_update_worker
, &vnode
->cb_broken_work
);
128 spin_unlock(&vnode
->lock
);
133 * allow the fileserver to explicitly break one callback
135 * - the backing file is changed
136 * - a lock is released
138 static void afs_break_one_callback(struct afs_server
*server
,
141 struct afs_vnode
*vnode
;
145 spin_lock(&server
->fs_lock
);
146 p
= server
->fs_vnodes
.rb_node
;
148 vnode
= rb_entry(p
, struct afs_vnode
, server_rb
);
149 if (fid
->vid
< vnode
->fid
.vid
)
151 else if (fid
->vid
> vnode
->fid
.vid
)
153 else if (fid
->vnode
< vnode
->fid
.vnode
)
155 else if (fid
->vnode
> vnode
->fid
.vnode
)
157 else if (fid
->unique
< vnode
->fid
.unique
)
159 else if (fid
->unique
> vnode
->fid
.unique
)
165 /* not found so we just ignore it (it may have moved to another
169 spin_unlock(&server
->fs_lock
);
175 ASSERTCMP(server
, ==, vnode
->server
);
177 if (!igrab(AFS_VNODE_TO_I(vnode
)))
179 spin_unlock(&server
->fs_lock
);
181 afs_break_callback(server
, vnode
);
182 iput(&vnode
->vfs_inode
);
187 * allow the fileserver to break callback promises
189 void afs_break_callbacks(struct afs_server
*server
, size_t count
,
190 struct afs_callback callbacks
[])
192 _enter("%p,%zu,", server
, count
);
194 ASSERT(server
!= NULL
);
195 ASSERTCMP(count
, <=, AFSCBMAX
);
197 for (; count
> 0; callbacks
++, count
--) {
198 _debug("- Fid { vl=%08x n=%u u=%u } CB { v=%u x=%u t=%u }",
200 callbacks
->fid
.vnode
,
201 callbacks
->fid
.unique
,
206 afs_break_one_callback(server
, &callbacks
->fid
);
214 * record the callback for breaking
215 * - the caller must hold server->cb_lock
217 static void afs_do_give_up_callback(struct afs_server
*server
,
218 struct afs_vnode
*vnode
)
220 struct afs_callback
*cb
;
222 _enter("%p,%p", server
, vnode
);
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
;
230 server
->cb_break_head
=
231 (server
->cb_break_head
+ 1) &
232 (ARRAY_SIZE(server
->cb_break
) - 1);
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);
242 afs_flush_callback_breaks(server
);
248 ASSERT(server
->cb_promises
.rb_node
!= NULL
);
249 rb_erase(&vnode
->cb_promise
, &server
->cb_promises
);
250 vnode
->cb_promised
= false;
255 * discard the callback on a deleted item
257 void afs_discard_callback_on_delete(struct afs_vnode
*vnode
)
259 struct afs_server
*server
= vnode
->server
;
261 _enter("%d", vnode
->cb_promised
);
263 if (!vnode
->cb_promised
) {
264 _leave(" [not promised]");
268 ASSERT(server
!= NULL
);
270 spin_lock(&server
->cb_lock
);
271 if (vnode
->cb_promised
) {
272 ASSERT(server
->cb_promises
.rb_node
!= NULL
);
273 rb_erase(&vnode
->cb_promise
, &server
->cb_promises
);
274 vnode
->cb_promised
= false;
276 spin_unlock(&server
->cb_lock
);
281 * give up the callback registered for a vnode on the file server when the
282 * inode is being cleared
284 void afs_give_up_callback(struct afs_vnode
*vnode
)
286 struct afs_server
*server
= vnode
->server
;
288 DECLARE_WAITQUEUE(myself
, current
);
290 _enter("%d", vnode
->cb_promised
);
292 _debug("GIVE UP INODE %p", &vnode
->vfs_inode
);
294 if (!vnode
->cb_promised
) {
295 _leave(" [not promised]");
299 ASSERT(server
!= NULL
);
301 spin_lock(&server
->cb_lock
);
302 if (vnode
->cb_promised
&& afs_breakring_space(server
) == 0) {
303 add_wait_queue(&server
->cb_break_waitq
, &myself
);
305 set_current_state(TASK_UNINTERRUPTIBLE
);
306 if (!vnode
->cb_promised
||
307 afs_breakring_space(server
) != 0)
309 spin_unlock(&server
->cb_lock
);
311 spin_lock(&server
->cb_lock
);
313 remove_wait_queue(&server
->cb_break_waitq
, &myself
);
314 __set_current_state(TASK_RUNNING
);
317 /* of course, it's always possible for the server to break this vnode's
318 * callback first... */
319 if (vnode
->cb_promised
)
320 afs_do_give_up_callback(server
, vnode
);
322 spin_unlock(&server
->cb_lock
);
327 * dispatch a deferred give up callbacks operation
329 void afs_dispatch_give_up_callbacks(struct work_struct
*work
)
331 struct afs_server
*server
=
332 container_of(work
, struct afs_server
, cb_break_work
.work
);
336 /* tell the fileserver to discard the callback promises it has
337 * - in the event of ENOMEM or some other error, we just forget that we
338 * had callbacks entirely, and the server will call us later to break
341 afs_fs_give_up_callbacks(server
, &afs_async_call
);
345 * flush the outstanding callback breaks on a server
347 void afs_flush_callback_breaks(struct afs_server
*server
)
349 cancel_delayed_work(&server
->cb_break_work
);
350 queue_delayed_work(afs_callback_update_worker
,
351 &server
->cb_break_work
, 0);
356 * update a bunch of callbacks
358 static void afs_callback_updater(struct work_struct
*work
)
360 struct afs_server
*server
;
361 struct afs_vnode
*vnode
, *xvnode
;
366 server
= container_of(work
, struct afs_server
, updater
);
372 /* find the first vnode to update */
373 spin_lock(&server
->cb_lock
);
375 if (RB_EMPTY_ROOT(&server
->cb_promises
)) {
376 spin_unlock(&server
->cb_lock
);
377 _leave(" [nothing]");
381 vnode
= rb_entry(rb_first(&server
->cb_promises
),
382 struct afs_vnode
, cb_promise
);
383 if (atomic_read(&vnode
->usage
) > 0)
385 rb_erase(&vnode
->cb_promise
, &server
->cb_promises
);
386 vnode
->cb_promised
= false;
389 timeout
= vnode
->update_at
- now
;
391 queue_delayed_work(afs_vnode_update_worker
,
392 &afs_vnode_update
, timeout
* HZ
);
393 spin_unlock(&server
->cb_lock
);
394 _leave(" [nothing]");
398 list_del_init(&vnode
->update
);
399 atomic_inc(&vnode
->usage
);
400 spin_unlock(&server
->cb_lock
);
402 /* we can now perform the update */
403 _debug("update %s", vnode
->vldb
.name
);
404 vnode
->state
= AFS_VL_UPDATING
;
405 vnode
->upd_rej_cnt
= 0;
406 vnode
->upd_busy_cnt
= 0;
408 ret
= afs_vnode_update_record(vl
, &vldb
);
411 afs_vnode_apply_update(vl
, &vldb
);
412 vnode
->state
= AFS_VL_UPDATING
;
415 vnode
->state
= AFS_VL_VOLUME_DELETED
;
418 vnode
->state
= AFS_VL_UNCERTAIN
;
422 /* and then reschedule */
423 _debug("reschedule");
424 vnode
->update_at
= get_seconds() + afs_vnode_update_timeout
;
426 spin_lock(&server
->cb_lock
);
428 if (!list_empty(&server
->cb_promises
)) {
429 /* next update in 10 minutes, but wait at least 1 second more
430 * than the newest record already queued so that we don't spam
431 * the VL server suddenly with lots of requests
433 xvnode
= list_entry(server
->cb_promises
.prev
,
434 struct afs_vnode
, update
);
435 if (vnode
->update_at
<= xvnode
->update_at
)
436 vnode
->update_at
= xvnode
->update_at
+ 1;
437 xvnode
= list_entry(server
->cb_promises
.next
,
438 struct afs_vnode
, update
);
439 timeout
= xvnode
->update_at
- now
;
443 timeout
= afs_vnode_update_timeout
;
446 list_add_tail(&vnode
->update
, &server
->cb_promises
);
448 _debug("timeout %ld", timeout
);
449 queue_delayed_work(afs_vnode_update_worker
,
450 &afs_vnode_update
, timeout
* HZ
);
451 spin_unlock(&server
->cb_lock
);
457 * initialise the callback update process
459 int __init
afs_callback_update_init(void)
461 afs_callback_update_worker
=
462 create_singlethread_workqueue("kafs_callbackd");
463 return afs_callback_update_worker
? 0 : -ENOMEM
;
467 * shut down the callback update process
469 void afs_callback_update_kill(void)
471 destroy_workqueue(afs_callback_update_worker
);