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>
22 unsigned afs_vnode_update_timeout = 10;
24 #define afs_breakring_space(server) \
25 CIRC_SPACE((server)->cb_break_head, (server)->cb_break_tail, \
26 ARRAY_SIZE((server)->cb_break))
28 //static void afs_callback_updater(struct work_struct *);
30 static struct workqueue_struct *afs_callback_update_worker;
33 * allow the fileserver to request callback state (re-)initialisation
35 void afs_init_callback_state(struct afs_server *server)
37 struct afs_vnode *vnode;
39 _enter("{%p}", server);
41 spin_lock(&server->cb_lock);
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;
52 spin_unlock(&server->cb_lock);
57 * handle the data invalidation side of a callback being broken
59 void afs_broken_callback_work(struct work_struct *work)
61 struct afs_vnode *vnode =
62 container_of(work, struct afs_vnode, cb_broken_work);
66 if (test_bit(AFS_VNODE_DELETED, &vnode->flags))
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 */
74 if (test_bit(AFS_VNODE_CB_BROKEN, &vnode->flags)) {
75 if (S_ISDIR(vnode->vfs_inode.i_mode))
76 afs_clear_permits(vnode);
78 if (afs_vnode_fetch_status(vnode, NULL, NULL) < 0)
81 if (test_bit(AFS_VNODE_DELETED, &vnode->flags))
84 /* if the vnode's data version number changed then its contents
86 if (test_and_clear_bit(AFS_VNODE_ZAP_DATA, &vnode->flags)) {
88 invalidate_remote_inode(&vnode->vfs_inode);
93 mutex_unlock(&vnode->cb_broken_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 * give up the callback registered for a vnode on the file server when the
256 * inode is being cleared
258 void afs_give_up_callback(struct afs_vnode *vnode)
260 struct afs_server *server = vnode->server;
262 DECLARE_WAITQUEUE(myself, current);
264 _enter("%d", vnode->cb_promised);
266 _debug("GIVE UP INODE %p", &vnode->vfs_inode);
268 if (!vnode->cb_promised) {
269 _leave(" [not promised]");
273 ASSERT(server != NULL);
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);
279 set_current_state(TASK_UNINTERRUPTIBLE);
280 if (!vnode->cb_promised ||
281 afs_breakring_space(server) != 0)
283 spin_unlock(&server->cb_lock);
285 spin_lock(&server->cb_lock);
287 remove_wait_queue(&server->cb_break_waitq, &myself);
288 __set_current_state(TASK_RUNNING);
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);
296 spin_unlock(&server->cb_lock);
301 * dispatch a deferred give up callbacks operation
303 void afs_dispatch_give_up_callbacks(struct work_struct *work)
305 struct afs_server *server =
306 container_of(work, struct afs_server, cb_break_work.work);
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
315 afs_fs_give_up_callbacks(server, &afs_async_call);
319 * flush the outstanding callback breaks on a server
321 void afs_flush_callback_breaks(struct afs_server *server)
323 cancel_delayed_work(&server->cb_break_work);
324 queue_delayed_work(afs_callback_update_worker,
325 &server->cb_break_work, 0);
330 * update a bunch of callbacks
332 static void afs_callback_updater(struct work_struct *work)
334 struct afs_server *server;
335 struct afs_vnode *vnode, *xvnode;
340 server = container_of(work, struct afs_server, updater);
346 /* find the first vnode to update */
347 spin_lock(&server->cb_lock);
349 if (RB_EMPTY_ROOT(&server->cb_promises)) {
350 spin_unlock(&server->cb_lock);
351 _leave(" [nothing]");
355 vnode = rb_entry(rb_first(&server->cb_promises),
356 struct afs_vnode, cb_promise);
357 if (atomic_read(&vnode->usage) > 0)
359 rb_erase(&vnode->cb_promise, &server->cb_promises);
360 vnode->cb_promised = false;
363 timeout = vnode->update_at - now;
365 queue_delayed_work(afs_vnode_update_worker,
366 &afs_vnode_update, timeout * HZ);
367 spin_unlock(&server->cb_lock);
368 _leave(" [nothing]");
372 list_del_init(&vnode->update);
373 atomic_inc(&vnode->usage);
374 spin_unlock(&server->cb_lock);
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;
382 ret = afs_vnode_update_record(vl, &vldb);
385 afs_vnode_apply_update(vl, &vldb);
386 vnode->state = AFS_VL_UPDATING;
389 vnode->state = AFS_VL_VOLUME_DELETED;
392 vnode->state = AFS_VL_UNCERTAIN;
396 /* and then reschedule */
397 _debug("reschedule");
398 vnode->update_at = get_seconds() + afs_vnode_update_timeout;
400 spin_lock(&server->cb_lock);
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
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;
417 timeout = afs_vnode_update_timeout;
420 list_add_tail(&vnode->update, &server->cb_promises);
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);
431 * initialise the callback update process
433 int __init afs_callback_update_init(void)
435 afs_callback_update_worker =
436 create_singlethread_workqueue("kafs_callbackd");
437 return afs_callback_update_worker ? 0 : -ENOMEM;
441 * shut down the callback update process
443 void __exit afs_callback_update_kill(void)
445 destroy_workqueue(afs_callback_update_worker);