Commit | Line | Data |
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1da177e4 | 1 | /* |
08e0e7c8 | 2 | * Copyright (c) 2002, 2007 Red Hat, Inc. All rights reserved. |
1da177e4 LT |
3 | * |
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> | |
08e0e7c8 | 19 | #include <linux/circ_buf.h> |
1da177e4 | 20 | #include "internal.h" |
08e0e7c8 DH |
21 | |
22 | unsigned 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 | ||
30 | static struct workqueue_struct *afs_callback_update_worker; | |
1da177e4 | 31 | |
1da177e4 LT |
32 | /* |
33 | * allow the fileserver to request callback state (re-)initialisation | |
34 | */ | |
08e0e7c8 | 35 | void afs_init_callback_state(struct afs_server *server) |
1da177e4 | 36 | { |
08e0e7c8 | 37 | struct afs_vnode *vnode; |
1da177e4 | 38 | |
08e0e7c8 | 39 | _enter("{%p}", server); |
1da177e4 | 40 | |
1da177e4 LT |
41 | spin_lock(&server->cb_lock); |
42 | ||
08e0e7c8 DH |
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); | |
260a9803 DH |
47 | _debug("UNPROMISE { vid=%x vn=%u uq=%u}", |
48 | vnode->fid.vid, vnode->fid.vnode, vnode->fid.unique); | |
08e0e7c8 DH |
49 | rb_erase(&vnode->cb_promise, &server->cb_promises); |
50 | vnode->cb_promised = false; | |
51 | } | |
1da177e4 | 52 | |
08e0e7c8 DH |
53 | spin_unlock(&server->cb_lock); |
54 | _leave(""); | |
55 | } | |
1da177e4 | 56 | |
08e0e7c8 DH |
57 | /* |
58 | * handle the data invalidation side of a callback being broken | |
59 | */ | |
60 | void afs_broken_callback_work(struct work_struct *work) | |
61 | { | |
62 | struct afs_vnode *vnode = | |
63 | container_of(work, struct afs_vnode, cb_broken_work); | |
1da177e4 | 64 | |
08e0e7c8 | 65 | _enter(""); |
1da177e4 | 66 | |
08e0e7c8 DH |
67 | if (test_bit(AFS_VNODE_DELETED, &vnode->flags)) |
68 | return; | |
1da177e4 | 69 | |
08e0e7c8 DH |
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 */ | |
260a9803 | 72 | if (!mutex_trylock(&vnode->validate_lock)) |
08e0e7c8 | 73 | return; /* someone else is dealing with it */ |
1da177e4 | 74 | |
08e0e7c8 | 75 | if (test_bit(AFS_VNODE_CB_BROKEN, &vnode->flags)) { |
00d3b7a4 DH |
76 | if (S_ISDIR(vnode->vfs_inode.i_mode)) |
77 | afs_clear_permits(vnode); | |
78 | ||
79 | if (afs_vnode_fetch_status(vnode, NULL, NULL) < 0) | |
08e0e7c8 | 80 | goto out; |
1da177e4 | 81 | |
08e0e7c8 DH |
82 | if (test_bit(AFS_VNODE_DELETED, &vnode->flags)) |
83 | goto out; | |
1da177e4 | 84 | |
08e0e7c8 DH |
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)) { | |
260a9803 DH |
88 | _debug("zap data {%x:%u}", |
89 | vnode->fid.vid, vnode->fid.vnode); | |
08e0e7c8 | 90 | invalidate_remote_inode(&vnode->vfs_inode); |
1da177e4 LT |
91 | } |
92 | } | |
93 | ||
08e0e7c8 | 94 | out: |
260a9803 | 95 | mutex_unlock(&vnode->validate_lock); |
1da177e4 | 96 | |
08e0e7c8 DH |
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 | */ | |
110 | static 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 | */ | |
140 | static 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) */ | |
169 | not_available: | |
170 | _debug("not avail"); | |
171 | spin_unlock(&server->fs_lock); | |
172 | _leave(""); | |
173 | return; | |
174 | ||
175 | found: | |
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(""); | |
ec26815a | 186 | } |
1da177e4 | 187 | |
1da177e4 LT |
188 | /* |
189 | * allow the fileserver to break callback promises | |
190 | */ | |
08e0e7c8 DH |
191 | void afs_break_callbacks(struct afs_server *server, size_t count, |
192 | struct afs_callback callbacks[]) | |
1da177e4 | 193 | { |
08e0e7c8 | 194 | _enter("%p,%zu,", server, count); |
1da177e4 | 195 | |
08e0e7c8 DH |
196 | ASSERT(server != NULL); |
197 | ASSERTCMP(count, <=, AFSCBMAX); | |
1da177e4 | 198 | |
08e0e7c8 | 199 | for (; count > 0; callbacks++, count--) { |
1da177e4 LT |
200 | _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 | ); | |
08e0e7c8 DH |
208 | afs_break_one_callback(server, &callbacks->fid); |
209 | } | |
210 | ||
211 | _leave(""); | |
212 | return; | |
213 | } | |
1da177e4 | 214 | |
08e0e7c8 DH |
215 | /* |
216 | * record the callback for breaking | |
217 | * - the caller must hold server->cb_lock | |
218 | */ | |
219 | static void afs_do_give_up_callback(struct afs_server *server, | |
220 | struct afs_vnode *vnode) | |
221 | { | |
222 | struct afs_callback *cb; | |
1da177e4 | 223 | |
08e0e7c8 | 224 | _enter("%p,%p", server, vnode); |
1da177e4 | 225 | |
08e0e7c8 DH |
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); | |
1da177e4 | 235 | |
08e0e7c8 DH |
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 | ||
260a9803 DH |
256 | /* |
257 | * discard the callback on a deleted item | |
258 | */ | |
259 | void 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 | ||
08e0e7c8 DH |
282 | /* |
283 | * give up the callback registered for a vnode on the file server when the | |
284 | * inode is being cleared | |
285 | */ | |
286 | void 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); | |
1da177e4 | 314 | } |
08e0e7c8 DH |
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 | */ | |
331 | void 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 | */ | |
349 | void 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 | */ | |
360 | static 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(""); | |
1da177e4 | 371 | |
08e0e7c8 DH |
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; | |
1da177e4 | 381 | } |
08e0e7c8 DH |
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; | |
1da177e4 LT |
446 | } |
447 | ||
08e0e7c8 DH |
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 | */ | |
461 | int __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; | |
ec26815a | 466 | } |
1da177e4 | 467 | |
1da177e4 | 468 | /* |
08e0e7c8 | 469 | * shut down the callback update process |
1da177e4 | 470 | */ |
fbb3fcba | 471 | void afs_callback_update_kill(void) |
1da177e4 | 472 | { |
08e0e7c8 | 473 | destroy_workqueue(afs_callback_update_worker); |
ec26815a | 474 | } |