blob: 9bdbf36a9aa9ac20fe3ecb94f4403483af74ad0e [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
David Howells08e0e7c2007-04-26 15:55:03 -07002 * Copyright (c) 2002, 2007 Red Hat, Inc. All rights reserved.
Linus Torvalds1da177e2005-04-16 15:20:36 -07003 *
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 *
11 * Authors: David Woodhouse <dwmw2@cambridge.redhat.com>
12 * David Howells <dhowells@redhat.com>
13 *
14 */
15
16#include <linux/kernel.h>
17#include <linux/module.h>
18#include <linux/init.h>
David Howells08e0e7c2007-04-26 15:55:03 -070019#include <linux/circ_buf.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070020#include "internal.h"
David Howells08e0e7c2007-04-26 15:55:03 -070021
22unsigned afs_vnode_update_timeout = 10;
23
24#define afs_breakring_space(server) \
25 CIRC_SPACE((server)->cb_break_head, (server)->cb_break_tail, \
26 ARRAY_SIZE((server)->cb_break))
27
28//static void afs_callback_updater(struct work_struct *);
29
30static struct workqueue_struct *afs_callback_update_worker;
Linus Torvalds1da177e2005-04-16 15:20:36 -070031
Linus Torvalds1da177e2005-04-16 15:20:36 -070032/*
33 * allow the fileserver to request callback state (re-)initialisation
34 */
David Howells08e0e7c2007-04-26 15:55:03 -070035void afs_init_callback_state(struct afs_server *server)
Linus Torvalds1da177e2005-04-16 15:20:36 -070036{
David Howells08e0e7c2007-04-26 15:55:03 -070037 struct afs_vnode *vnode;
Linus Torvalds1da177e2005-04-16 15:20:36 -070038
David Howells08e0e7c2007-04-26 15:55:03 -070039 _enter("{%p}", server);
Linus Torvalds1da177e2005-04-16 15:20:36 -070040
Linus Torvalds1da177e2005-04-16 15:20:36 -070041 spin_lock(&server->cb_lock);
42
David Howells08e0e7c2007-04-26 15:55:03 -070043 /* 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);
David Howells260a9802007-04-26 15:59:35 -070047 _debug("UNPROMISE { vid=%x vn=%u uq=%u}",
48 vnode->fid.vid, vnode->fid.vnode, vnode->fid.unique);
David Howells08e0e7c2007-04-26 15:55:03 -070049 rb_erase(&vnode->cb_promise, &server->cb_promises);
50 vnode->cb_promised = false;
Linus Torvalds1da177e2005-04-16 15:20:36 -070051 }
52
53 spin_unlock(&server->cb_lock);
David Howells08e0e7c2007-04-26 15:55:03 -070054 _leave("");
55}
Linus Torvalds1da177e2005-04-16 15:20:36 -070056
David Howells08e0e7c2007-04-26 15:55:03 -070057/*
58 * handle the data invalidation side of a callback being broken
59 */
60void afs_broken_callback_work(struct work_struct *work)
61{
62 struct afs_vnode *vnode =
63 container_of(work, struct afs_vnode, cb_broken_work);
64
65 _enter("");
66
67 if (test_bit(AFS_VNODE_DELETED, &vnode->flags))
68 return;
69
70 /* we're only interested in dealing with a broken callback on *this*
71 * vnode and only if no-one else has dealt with it yet */
David Howells260a9802007-04-26 15:59:35 -070072 if (!mutex_trylock(&vnode->validate_lock))
David Howells08e0e7c2007-04-26 15:55:03 -070073 return; /* someone else is dealing with it */
74
75 if (test_bit(AFS_VNODE_CB_BROKEN, &vnode->flags)) {
David Howells00d3b7a2007-04-26 15:57:07 -070076 if (S_ISDIR(vnode->vfs_inode.i_mode))
77 afs_clear_permits(vnode);
78
79 if (afs_vnode_fetch_status(vnode, NULL, NULL) < 0)
David Howells08e0e7c2007-04-26 15:55:03 -070080 goto out;
81
82 if (test_bit(AFS_VNODE_DELETED, &vnode->flags))
83 goto out;
84
85 /* if the vnode's data version number changed then its contents
86 * are different */
87 if (test_and_clear_bit(AFS_VNODE_ZAP_DATA, &vnode->flags)) {
David Howells260a9802007-04-26 15:59:35 -070088 _debug("zap data {%x:%u}",
89 vnode->fid.vid, vnode->fid.vnode);
David Howells08e0e7c2007-04-26 15:55:03 -070090 invalidate_remote_inode(&vnode->vfs_inode);
91 }
92 }
93
94out:
David Howells260a9802007-04-26 15:59:35 -070095 mutex_unlock(&vnode->validate_lock);
David Howells08e0e7c2007-04-26 15:55:03 -070096
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 */
110static 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);
130 spin_unlock(&vnode->lock);
131 }
132}
133
134/*
135 * allow the fileserver to explicitly break one callback
136 * - happens when
137 * - the backing file is changed
138 * - a lock is released
139 */
140static void afs_break_one_callback(struct afs_server *server,
141 struct afs_fid *fid)
142{
143 struct afs_vnode *vnode;
144 struct rb_node *p;
145
146 _debug("find");
147 spin_lock(&server->fs_lock);
148 p = server->fs_vnodes.rb_node;
149 while (p) {
150 vnode = rb_entry(p, struct afs_vnode, server_rb);
151 if (fid->vid < vnode->fid.vid)
152 p = p->rb_left;
153 else if (fid->vid > vnode->fid.vid)
154 p = p->rb_right;
155 else if (fid->vnode < vnode->fid.vnode)
156 p = p->rb_left;
157 else if (fid->vnode > vnode->fid.vnode)
158 p = p->rb_right;
159 else if (fid->unique < vnode->fid.unique)
160 p = p->rb_left;
161 else if (fid->unique > vnode->fid.unique)
162 p = p->rb_right;
163 else
164 goto found;
165 }
166
167 /* not found so we just ignore it (it may have moved to another
168 * server) */
169not_available:
170 _debug("not avail");
171 spin_unlock(&server->fs_lock);
172 _leave("");
173 return;
174
175found:
176 _debug("found");
177 ASSERTCMP(server, ==, vnode->server);
178
179 if (!igrab(AFS_VNODE_TO_I(vnode)))
180 goto not_available;
181 spin_unlock(&server->fs_lock);
182
183 afs_break_callback(server, vnode);
184 iput(&vnode->vfs_inode);
185 _leave("");
David Howellsec268152007-04-26 15:49:28 -0700186}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700187
Linus Torvalds1da177e2005-04-16 15:20:36 -0700188/*
189 * allow the fileserver to break callback promises
190 */
David Howells08e0e7c2007-04-26 15:55:03 -0700191void afs_break_callbacks(struct afs_server *server, size_t count,
192 struct afs_callback callbacks[])
Linus Torvalds1da177e2005-04-16 15:20:36 -0700193{
David Howells08e0e7c2007-04-26 15:55:03 -0700194 _enter("%p,%zu,", server, count);
195
196 ASSERT(server != NULL);
197 ASSERTCMP(count, <=, AFSCBMAX);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700198
199 for (; count > 0; callbacks++, count--) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700200 _debug("- Fid { vl=%08x n=%u u=%u } CB { v=%u x=%u t=%u }",
201 callbacks->fid.vid,
202 callbacks->fid.vnode,
203 callbacks->fid.unique,
204 callbacks->version,
205 callbacks->expiry,
206 callbacks->type
207 );
David Howells08e0e7c2007-04-26 15:55:03 -0700208 afs_break_one_callback(server, &callbacks->fid);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700209 }
210
David Howells08e0e7c2007-04-26 15:55:03 -0700211 _leave("");
212 return;
David Howellsec268152007-04-26 15:49:28 -0700213}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700214
Linus Torvalds1da177e2005-04-16 15:20:36 -0700215/*
David Howells08e0e7c2007-04-26 15:55:03 -0700216 * record the callback for breaking
217 * - the caller must hold server->cb_lock
Linus Torvalds1da177e2005-04-16 15:20:36 -0700218 */
David Howells08e0e7c2007-04-26 15:55:03 -0700219static void afs_do_give_up_callback(struct afs_server *server,
220 struct afs_vnode *vnode)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700221{
David Howells08e0e7c2007-04-26 15:55:03 -0700222 struct afs_callback *cb;
223
224 _enter("%p,%p", server, vnode);
225
226 cb = &server->cb_break[server->cb_break_head];
227 cb->fid = vnode->fid;
228 cb->version = vnode->cb_version;
229 cb->expiry = vnode->cb_expiry;
230 cb->type = vnode->cb_type;
231 smp_wmb();
232 server->cb_break_head =
233 (server->cb_break_head + 1) &
234 (ARRAY_SIZE(server->cb_break) - 1);
235
236 /* defer the breaking of callbacks to try and collect as many as
237 * possible to ship in one operation */
238 switch (atomic_inc_return(&server->cb_break_n)) {
239 case 1 ... AFSCBMAX - 1:
240 queue_delayed_work(afs_callback_update_worker,
241 &server->cb_break_work, HZ * 2);
242 break;
243 case AFSCBMAX:
244 afs_flush_callback_breaks(server);
245 break;
246 default:
247 break;
248 }
249
250 ASSERT(server->cb_promises.rb_node != NULL);
251 rb_erase(&vnode->cb_promise, &server->cb_promises);
252 vnode->cb_promised = false;
253 _leave("");
254}
255
256/*
David Howells260a9802007-04-26 15:59:35 -0700257 * discard the callback on a deleted item
258 */
259void afs_discard_callback_on_delete(struct afs_vnode *vnode)
260{
261 struct afs_server *server = vnode->server;
262
263 _enter("%d", vnode->cb_promised);
264
265 if (!vnode->cb_promised) {
266 _leave(" [not promised]");
267 return;
268 }
269
270 ASSERT(server != NULL);
271
272 spin_lock(&server->cb_lock);
273 if (vnode->cb_promised) {
274 ASSERT(server->cb_promises.rb_node != NULL);
275 rb_erase(&vnode->cb_promise, &server->cb_promises);
276 vnode->cb_promised = false;
277 }
278 spin_unlock(&server->cb_lock);
279 _leave("");
280}
281
282/*
David Howells08e0e7c2007-04-26 15:55:03 -0700283 * give up the callback registered for a vnode on the file server when the
284 * inode is being cleared
285 */
286void afs_give_up_callback(struct afs_vnode *vnode)
287{
288 struct afs_server *server = vnode->server;
289
290 DECLARE_WAITQUEUE(myself, current);
291
292 _enter("%d", vnode->cb_promised);
293
294 _debug("GIVE UP INODE %p", &vnode->vfs_inode);
295
296 if (!vnode->cb_promised) {
297 _leave(" [not promised]");
298 return;
299 }
300
301 ASSERT(server != NULL);
302
303 spin_lock(&server->cb_lock);
304 if (vnode->cb_promised && afs_breakring_space(server) == 0) {
305 add_wait_queue(&server->cb_break_waitq, &myself);
306 for (;;) {
307 set_current_state(TASK_UNINTERRUPTIBLE);
308 if (!vnode->cb_promised ||
309 afs_breakring_space(server) != 0)
310 break;
311 spin_unlock(&server->cb_lock);
312 schedule();
313 spin_lock(&server->cb_lock);
314 }
315 remove_wait_queue(&server->cb_break_waitq, &myself);
316 __set_current_state(TASK_RUNNING);
317 }
318
319 /* of course, it's always possible for the server to break this vnode's
320 * callback first... */
321 if (vnode->cb_promised)
322 afs_do_give_up_callback(server, vnode);
323
324 spin_unlock(&server->cb_lock);
325 _leave("");
326}
327
328/*
329 * dispatch a deferred give up callbacks operation
330 */
331void afs_dispatch_give_up_callbacks(struct work_struct *work)
332{
333 struct afs_server *server =
334 container_of(work, struct afs_server, cb_break_work.work);
335
336 _enter("");
337
338 /* tell the fileserver to discard the callback promises it has
339 * - in the event of ENOMEM or some other error, we just forget that we
340 * had callbacks entirely, and the server will call us later to break
341 * them
342 */
343 afs_fs_give_up_callbacks(server, &afs_async_call);
344}
345
346/*
347 * flush the outstanding callback breaks on a server
348 */
349void afs_flush_callback_breaks(struct afs_server *server)
350{
351 cancel_delayed_work(&server->cb_break_work);
352 queue_delayed_work(afs_callback_update_worker,
353 &server->cb_break_work, 0);
354}
355
356#if 0
357/*
358 * update a bunch of callbacks
359 */
360static void afs_callback_updater(struct work_struct *work)
361{
362 struct afs_server *server;
363 struct afs_vnode *vnode, *xvnode;
364 time_t now;
365 long timeout;
366 int ret;
367
368 server = container_of(work, struct afs_server, updater);
369
370 _enter("");
371
372 now = get_seconds();
373
374 /* find the first vnode to update */
375 spin_lock(&server->cb_lock);
376 for (;;) {
377 if (RB_EMPTY_ROOT(&server->cb_promises)) {
378 spin_unlock(&server->cb_lock);
379 _leave(" [nothing]");
380 return;
381 }
382
383 vnode = rb_entry(rb_first(&server->cb_promises),
384 struct afs_vnode, cb_promise);
385 if (atomic_read(&vnode->usage) > 0)
386 break;
387 rb_erase(&vnode->cb_promise, &server->cb_promises);
388 vnode->cb_promised = false;
389 }
390
391 timeout = vnode->update_at - now;
392 if (timeout > 0) {
393 queue_delayed_work(afs_vnode_update_worker,
394 &afs_vnode_update, timeout * HZ);
395 spin_unlock(&server->cb_lock);
396 _leave(" [nothing]");
397 return;
398 }
399
400 list_del_init(&vnode->update);
401 atomic_inc(&vnode->usage);
402 spin_unlock(&server->cb_lock);
403
404 /* we can now perform the update */
405 _debug("update %s", vnode->vldb.name);
406 vnode->state = AFS_VL_UPDATING;
407 vnode->upd_rej_cnt = 0;
408 vnode->upd_busy_cnt = 0;
409
410 ret = afs_vnode_update_record(vl, &vldb);
411 switch (ret) {
412 case 0:
413 afs_vnode_apply_update(vl, &vldb);
414 vnode->state = AFS_VL_UPDATING;
415 break;
416 case -ENOMEDIUM:
417 vnode->state = AFS_VL_VOLUME_DELETED;
418 break;
419 default:
420 vnode->state = AFS_VL_UNCERTAIN;
421 break;
422 }
423
424 /* and then reschedule */
425 _debug("reschedule");
426 vnode->update_at = get_seconds() + afs_vnode_update_timeout;
427
428 spin_lock(&server->cb_lock);
429
430 if (!list_empty(&server->cb_promises)) {
431 /* next update in 10 minutes, but wait at least 1 second more
432 * than the newest record already queued so that we don't spam
433 * the VL server suddenly with lots of requests
434 */
435 xvnode = list_entry(server->cb_promises.prev,
436 struct afs_vnode, update);
437 if (vnode->update_at <= xvnode->update_at)
438 vnode->update_at = xvnode->update_at + 1;
439 xvnode = list_entry(server->cb_promises.next,
440 struct afs_vnode, update);
441 timeout = xvnode->update_at - now;
442 if (timeout < 0)
443 timeout = 0;
444 } else {
445 timeout = afs_vnode_update_timeout;
446 }
447
448 list_add_tail(&vnode->update, &server->cb_promises);
449
450 _debug("timeout %ld", timeout);
451 queue_delayed_work(afs_vnode_update_worker,
452 &afs_vnode_update, timeout * HZ);
453 spin_unlock(&server->cb_lock);
454 afs_put_vnode(vl);
455}
456#endif
457
458/*
459 * initialise the callback update process
460 */
461int __init afs_callback_update_init(void)
462{
463 afs_callback_update_worker =
464 create_singlethread_workqueue("kafs_callbackd");
465 return afs_callback_update_worker ? 0 : -ENOMEM;
466}
467
468/*
469 * shut down the callback update process
470 */
David Howellsfbb3fcb2007-05-03 03:12:46 -0700471void afs_callback_update_kill(void)
David Howells08e0e7c2007-04-26 15:55:03 -0700472{
473 destroy_workqueue(afs_callback_update_worker);
David Howellsec268152007-04-26 15:49:28 -0700474}