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1 | /* AFS volume location management | |
2 | * | |
3 | * Copyright (C) 2002, 2007 Red Hat, Inc. All Rights Reserved. | |
4 | * Written by David Howells (dhowells@redhat.com) | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or | |
7 | * modify it under the terms of the GNU General Public License | |
8 | * as published by the Free Software Foundation; either version | |
9 | * 2 of the License, or (at your option) any later version. | |
10 | */ | |
11 | ||
12 | #include <linux/kernel.h> | |
13 | #include <linux/module.h> | |
14 | #include <linux/init.h> | |
15 | #include <linux/sched.h> | |
16 | #include "internal.h" | |
17 | ||
18 | unsigned afs_vlocation_timeout = 10; /* volume location timeout in seconds */ | |
19 | unsigned afs_vlocation_update_timeout = 10 * 60; | |
20 | ||
21 | static void afs_vlocation_reaper(struct work_struct *); | |
22 | static void afs_vlocation_updater(struct work_struct *); | |
23 | ||
24 | static LIST_HEAD(afs_vlocation_updates); | |
25 | static LIST_HEAD(afs_vlocation_graveyard); | |
26 | static DEFINE_SPINLOCK(afs_vlocation_updates_lock); | |
27 | static DEFINE_SPINLOCK(afs_vlocation_graveyard_lock); | |
28 | static DECLARE_DELAYED_WORK(afs_vlocation_reap, afs_vlocation_reaper); | |
29 | static DECLARE_DELAYED_WORK(afs_vlocation_update, afs_vlocation_updater); | |
30 | static struct workqueue_struct *afs_vlocation_update_worker; | |
31 | ||
32 | /* | |
33 | * iterate through the VL servers in a cell until one of them admits knowing | |
34 | * about the volume in question | |
35 | */ | |
36 | static int afs_vlocation_access_vl_by_name(struct afs_vlocation *vl, | |
37 | struct key *key, | |
38 | struct afs_cache_vlocation *vldb) | |
39 | { | |
40 | struct afs_cell *cell = vl->cell; | |
41 | struct in_addr addr; | |
42 | int count, ret; | |
43 | ||
44 | _enter("%s,%s", cell->name, vl->vldb.name); | |
45 | ||
46 | down_write(&vl->cell->vl_sem); | |
47 | ret = -ENOMEDIUM; | |
48 | for (count = cell->vl_naddrs; count > 0; count--) { | |
49 | addr = cell->vl_addrs[cell->vl_curr_svix]; | |
50 | ||
51 | _debug("CellServ[%hu]: %08x", cell->vl_curr_svix, addr.s_addr); | |
52 | ||
53 | /* attempt to access the VL server */ | |
54 | ret = afs_vl_get_entry_by_name(&addr, key, vl->vldb.name, vldb, | |
55 | &afs_sync_call); | |
56 | switch (ret) { | |
57 | case 0: | |
58 | goto out; | |
59 | case -ENOMEM: | |
60 | case -ENONET: | |
61 | case -ENETUNREACH: | |
62 | case -EHOSTUNREACH: | |
63 | case -ECONNREFUSED: | |
64 | if (ret == -ENOMEM || ret == -ENONET) | |
65 | goto out; | |
66 | goto rotate; | |
67 | case -ENOMEDIUM: | |
68 | goto out; | |
69 | default: | |
70 | ret = -EIO; | |
71 | goto rotate; | |
72 | } | |
73 | ||
74 | /* rotate the server records upon lookup failure */ | |
75 | rotate: | |
76 | cell->vl_curr_svix++; | |
77 | cell->vl_curr_svix %= cell->vl_naddrs; | |
78 | } | |
79 | ||
80 | out: | |
81 | up_write(&vl->cell->vl_sem); | |
82 | _leave(" = %d", ret); | |
83 | return ret; | |
84 | } | |
85 | ||
86 | /* | |
87 | * iterate through the VL servers in a cell until one of them admits knowing | |
88 | * about the volume in question | |
89 | */ | |
90 | static int afs_vlocation_access_vl_by_id(struct afs_vlocation *vl, | |
91 | struct key *key, | |
92 | afs_volid_t volid, | |
93 | afs_voltype_t voltype, | |
94 | struct afs_cache_vlocation *vldb) | |
95 | { | |
96 | struct afs_cell *cell = vl->cell; | |
97 | struct in_addr addr; | |
98 | int count, ret; | |
99 | ||
100 | _enter("%s,%x,%d,", cell->name, volid, voltype); | |
101 | ||
102 | down_write(&vl->cell->vl_sem); | |
103 | ret = -ENOMEDIUM; | |
104 | for (count = cell->vl_naddrs; count > 0; count--) { | |
105 | addr = cell->vl_addrs[cell->vl_curr_svix]; | |
106 | ||
107 | _debug("CellServ[%hu]: %08x", cell->vl_curr_svix, addr.s_addr); | |
108 | ||
109 | /* attempt to access the VL server */ | |
110 | ret = afs_vl_get_entry_by_id(&addr, key, volid, voltype, vldb, | |
111 | &afs_sync_call); | |
112 | switch (ret) { | |
113 | case 0: | |
114 | goto out; | |
115 | case -ENOMEM: | |
116 | case -ENONET: | |
117 | case -ENETUNREACH: | |
118 | case -EHOSTUNREACH: | |
119 | case -ECONNREFUSED: | |
120 | if (ret == -ENOMEM || ret == -ENONET) | |
121 | goto out; | |
122 | goto rotate; | |
123 | case -EBUSY: | |
124 | vl->upd_busy_cnt++; | |
125 | if (vl->upd_busy_cnt <= 3) { | |
126 | if (vl->upd_busy_cnt > 1) { | |
127 | /* second+ BUSY - sleep a little bit */ | |
128 | set_current_state(TASK_UNINTERRUPTIBLE); | |
129 | schedule_timeout(1); | |
130 | __set_current_state(TASK_RUNNING); | |
131 | } | |
132 | continue; | |
133 | } | |
134 | break; | |
135 | case -ENOMEDIUM: | |
136 | vl->upd_rej_cnt++; | |
137 | goto rotate; | |
138 | default: | |
139 | ret = -EIO; | |
140 | goto rotate; | |
141 | } | |
142 | ||
143 | /* rotate the server records upon lookup failure */ | |
144 | rotate: | |
145 | cell->vl_curr_svix++; | |
146 | cell->vl_curr_svix %= cell->vl_naddrs; | |
147 | vl->upd_busy_cnt = 0; | |
148 | } | |
149 | ||
150 | out: | |
151 | if (ret < 0 && vl->upd_rej_cnt > 0) { | |
152 | printk(KERN_NOTICE "kAFS:" | |
153 | " Active volume no longer valid '%s'\n", | |
154 | vl->vldb.name); | |
155 | vl->valid = 0; | |
156 | ret = -ENOMEDIUM; | |
157 | } | |
158 | ||
159 | up_write(&vl->cell->vl_sem); | |
160 | _leave(" = %d", ret); | |
161 | return ret; | |
162 | } | |
163 | ||
164 | /* | |
165 | * allocate a volume location record | |
166 | */ | |
167 | static struct afs_vlocation *afs_vlocation_alloc(struct afs_cell *cell, | |
168 | const char *name, | |
169 | size_t namesz) | |
170 | { | |
171 | struct afs_vlocation *vl; | |
172 | ||
173 | vl = kzalloc(sizeof(struct afs_vlocation), GFP_KERNEL); | |
174 | if (vl) { | |
175 | vl->cell = cell; | |
176 | vl->state = AFS_VL_NEW; | |
177 | atomic_set(&vl->usage, 1); | |
178 | INIT_LIST_HEAD(&vl->link); | |
179 | INIT_LIST_HEAD(&vl->grave); | |
180 | INIT_LIST_HEAD(&vl->update); | |
181 | init_waitqueue_head(&vl->waitq); | |
182 | spin_lock_init(&vl->lock); | |
183 | memcpy(vl->vldb.name, name, namesz); | |
184 | } | |
185 | ||
186 | _leave(" = %p", vl); | |
187 | return vl; | |
188 | } | |
189 | ||
190 | /* | |
191 | * update record if we found it in the cache | |
192 | */ | |
193 | static int afs_vlocation_update_record(struct afs_vlocation *vl, | |
194 | struct key *key, | |
195 | struct afs_cache_vlocation *vldb) | |
196 | { | |
197 | afs_voltype_t voltype; | |
198 | afs_volid_t vid; | |
199 | int ret; | |
200 | ||
201 | /* try to look up a cached volume in the cell VL databases by ID */ | |
202 | _debug("Locally Cached: %s %02x { %08x(%x) %08x(%x) %08x(%x) }", | |
203 | vl->vldb.name, | |
204 | vl->vldb.vidmask, | |
205 | ntohl(vl->vldb.servers[0].s_addr), | |
206 | vl->vldb.srvtmask[0], | |
207 | ntohl(vl->vldb.servers[1].s_addr), | |
208 | vl->vldb.srvtmask[1], | |
209 | ntohl(vl->vldb.servers[2].s_addr), | |
210 | vl->vldb.srvtmask[2]); | |
211 | ||
212 | _debug("Vids: %08x %08x %08x", | |
213 | vl->vldb.vid[0], | |
214 | vl->vldb.vid[1], | |
215 | vl->vldb.vid[2]); | |
216 | ||
217 | if (vl->vldb.vidmask & AFS_VOL_VTM_RW) { | |
218 | vid = vl->vldb.vid[0]; | |
219 | voltype = AFSVL_RWVOL; | |
220 | } else if (vl->vldb.vidmask & AFS_VOL_VTM_RO) { | |
221 | vid = vl->vldb.vid[1]; | |
222 | voltype = AFSVL_ROVOL; | |
223 | } else if (vl->vldb.vidmask & AFS_VOL_VTM_BAK) { | |
224 | vid = vl->vldb.vid[2]; | |
225 | voltype = AFSVL_BACKVOL; | |
226 | } else { | |
227 | BUG(); | |
228 | vid = 0; | |
229 | voltype = 0; | |
230 | } | |
231 | ||
232 | /* contact the server to make sure the volume is still available | |
233 | * - TODO: need to handle disconnected operation here | |
234 | */ | |
235 | ret = afs_vlocation_access_vl_by_id(vl, key, vid, voltype, vldb); | |
236 | switch (ret) { | |
237 | /* net error */ | |
238 | default: | |
239 | printk(KERN_WARNING "kAFS:" | |
240 | " failed to update volume '%s' (%x) up in '%s': %d\n", | |
241 | vl->vldb.name, vid, vl->cell->name, ret); | |
242 | _leave(" = %d", ret); | |
243 | return ret; | |
244 | ||
245 | /* pulled from local cache into memory */ | |
246 | case 0: | |
247 | _leave(" = 0"); | |
248 | return 0; | |
249 | ||
250 | /* uh oh... looks like the volume got deleted */ | |
251 | case -ENOMEDIUM: | |
252 | printk(KERN_ERR "kAFS:" | |
253 | " volume '%s' (%x) does not exist '%s'\n", | |
254 | vl->vldb.name, vid, vl->cell->name); | |
255 | ||
256 | /* TODO: make existing record unavailable */ | |
257 | _leave(" = %d", ret); | |
258 | return ret; | |
259 | } | |
260 | } | |
261 | ||
262 | /* | |
263 | * apply the update to a VL record | |
264 | */ | |
265 | static void afs_vlocation_apply_update(struct afs_vlocation *vl, | |
266 | struct afs_cache_vlocation *vldb) | |
267 | { | |
268 | _debug("Done VL Lookup: %s %02x { %08x(%x) %08x(%x) %08x(%x) }", | |
269 | vldb->name, vldb->vidmask, | |
270 | ntohl(vldb->servers[0].s_addr), vldb->srvtmask[0], | |
271 | ntohl(vldb->servers[1].s_addr), vldb->srvtmask[1], | |
272 | ntohl(vldb->servers[2].s_addr), vldb->srvtmask[2]); | |
273 | ||
274 | _debug("Vids: %08x %08x %08x", | |
275 | vldb->vid[0], vldb->vid[1], vldb->vid[2]); | |
276 | ||
277 | if (strcmp(vldb->name, vl->vldb.name) != 0) | |
278 | printk(KERN_NOTICE "kAFS:" | |
279 | " name of volume '%s' changed to '%s' on server\n", | |
280 | vl->vldb.name, vldb->name); | |
281 | ||
282 | vl->vldb = *vldb; | |
283 | ||
284 | #ifdef AFS_CACHING_SUPPORT | |
285 | /* update volume entry in local cache */ | |
286 | cachefs_update_cookie(vl->cache); | |
287 | #endif | |
288 | } | |
289 | ||
290 | /* | |
291 | * fill in a volume location record, consulting the cache and the VL server | |
292 | * both | |
293 | */ | |
294 | static int afs_vlocation_fill_in_record(struct afs_vlocation *vl, | |
295 | struct key *key) | |
296 | { | |
297 | struct afs_cache_vlocation vldb; | |
298 | int ret; | |
299 | ||
300 | _enter(""); | |
301 | ||
302 | ASSERTCMP(vl->valid, ==, 0); | |
303 | ||
304 | memset(&vldb, 0, sizeof(vldb)); | |
305 | ||
306 | /* see if we have an in-cache copy (will set vl->valid if there is) */ | |
307 | #ifdef AFS_CACHING_SUPPORT | |
308 | cachefs_acquire_cookie(cell->cache, | |
309 | &afs_volume_cache_index_def, | |
310 | vlocation, | |
311 | &vl->cache); | |
312 | #endif | |
313 | ||
314 | if (vl->valid) { | |
315 | /* try to update a known volume in the cell VL databases by | |
316 | * ID as the name may have changed */ | |
317 | _debug("found in cache"); | |
318 | ret = afs_vlocation_update_record(vl, key, &vldb); | |
319 | } else { | |
320 | /* try to look up an unknown volume in the cell VL databases by | |
321 | * name */ | |
322 | ret = afs_vlocation_access_vl_by_name(vl, key, &vldb); | |
323 | if (ret < 0) { | |
324 | printk("kAFS: failed to locate '%s' in cell '%s'\n", | |
325 | vl->vldb.name, vl->cell->name); | |
326 | return ret; | |
327 | } | |
328 | } | |
329 | ||
330 | afs_vlocation_apply_update(vl, &vldb); | |
331 | _leave(" = 0"); | |
332 | return 0; | |
333 | } | |
334 | ||
335 | /* | |
336 | * queue a vlocation record for updates | |
337 | */ | |
338 | void afs_vlocation_queue_for_updates(struct afs_vlocation *vl) | |
339 | { | |
340 | struct afs_vlocation *xvl; | |
341 | ||
342 | /* wait at least 10 minutes before updating... */ | |
343 | vl->update_at = get_seconds() + afs_vlocation_update_timeout; | |
344 | ||
345 | spin_lock(&afs_vlocation_updates_lock); | |
346 | ||
347 | if (!list_empty(&afs_vlocation_updates)) { | |
348 | /* ... but wait at least 1 second more than the newest record | |
349 | * already queued so that we don't spam the VL server suddenly | |
350 | * with lots of requests | |
351 | */ | |
352 | xvl = list_entry(afs_vlocation_updates.prev, | |
353 | struct afs_vlocation, update); | |
354 | if (vl->update_at <= xvl->update_at) | |
355 | vl->update_at = xvl->update_at + 1; | |
356 | } else { | |
357 | queue_delayed_work(afs_vlocation_update_worker, | |
358 | &afs_vlocation_update, | |
359 | afs_vlocation_update_timeout * HZ); | |
360 | } | |
361 | ||
362 | list_add_tail(&vl->update, &afs_vlocation_updates); | |
363 | spin_unlock(&afs_vlocation_updates_lock); | |
364 | } | |
365 | ||
366 | /* | |
367 | * lookup volume location | |
368 | * - iterate through the VL servers in a cell until one of them admits knowing | |
369 | * about the volume in question | |
370 | * - lookup in the local cache if not able to find on the VL server | |
371 | * - insert/update in the local cache if did get a VL response | |
372 | */ | |
373 | struct afs_vlocation *afs_vlocation_lookup(struct afs_cell *cell, | |
374 | struct key *key, | |
375 | const char *name, | |
376 | size_t namesz) | |
377 | { | |
378 | struct afs_vlocation *vl; | |
379 | int ret; | |
380 | ||
381 | _enter("{%s},{%x},%*.*s,%zu", | |
382 | cell->name, key_serial(key), | |
383 | (int) namesz, (int) namesz, name, namesz); | |
384 | ||
385 | if (namesz > sizeof(vl->vldb.name)) { | |
386 | _leave(" = -ENAMETOOLONG"); | |
387 | return ERR_PTR(-ENAMETOOLONG); | |
388 | } | |
389 | ||
390 | /* see if we have an in-memory copy first */ | |
391 | down_write(&cell->vl_sem); | |
392 | spin_lock(&cell->vl_lock); | |
393 | list_for_each_entry(vl, &cell->vl_list, link) { | |
394 | if (vl->vldb.name[namesz] != '\0') | |
395 | continue; | |
396 | if (memcmp(vl->vldb.name, name, namesz) == 0) | |
397 | goto found_in_memory; | |
398 | } | |
399 | spin_unlock(&cell->vl_lock); | |
400 | ||
401 | /* not in the cell's in-memory lists - create a new record */ | |
402 | vl = afs_vlocation_alloc(cell, name, namesz); | |
403 | if (!vl) { | |
404 | up_write(&cell->vl_sem); | |
405 | return ERR_PTR(-ENOMEM); | |
406 | } | |
407 | ||
408 | afs_get_cell(cell); | |
409 | ||
410 | list_add_tail(&vl->link, &cell->vl_list); | |
411 | vl->state = AFS_VL_CREATING; | |
412 | up_write(&cell->vl_sem); | |
413 | ||
414 | fill_in_record: | |
415 | ret = afs_vlocation_fill_in_record(vl, key); | |
416 | if (ret < 0) | |
417 | goto error_abandon; | |
418 | spin_lock(&vl->lock); | |
419 | vl->state = AFS_VL_VALID; | |
420 | spin_unlock(&vl->lock); | |
421 | wake_up(&vl->waitq); | |
422 | ||
423 | /* schedule for regular updates */ | |
424 | afs_vlocation_queue_for_updates(vl); | |
425 | goto success; | |
426 | ||
427 | found_in_memory: | |
428 | /* found in memory */ | |
429 | _debug("found in memory"); | |
430 | atomic_inc(&vl->usage); | |
431 | spin_unlock(&cell->vl_lock); | |
432 | if (!list_empty(&vl->grave)) { | |
433 | spin_lock(&afs_vlocation_graveyard_lock); | |
434 | list_del_init(&vl->grave); | |
435 | spin_unlock(&afs_vlocation_graveyard_lock); | |
436 | } | |
437 | up_write(&cell->vl_sem); | |
438 | ||
439 | /* see if it was an abandoned record that we might try filling in */ | |
440 | spin_lock(&vl->lock); | |
441 | while (vl->state != AFS_VL_VALID) { | |
442 | afs_vlocation_state_t state = vl->state; | |
443 | ||
444 | _debug("invalid [state %d]", state); | |
445 | ||
446 | if (state == AFS_VL_NEW || state == AFS_VL_NO_VOLUME) { | |
447 | vl->state = AFS_VL_CREATING; | |
448 | spin_unlock(&vl->lock); | |
449 | goto fill_in_record; | |
450 | } | |
451 | ||
452 | /* must now wait for creation or update by someone else to | |
453 | * complete */ | |
454 | _debug("wait"); | |
455 | ||
456 | spin_unlock(&vl->lock); | |
457 | ret = wait_event_interruptible(vl->waitq, | |
458 | vl->state == AFS_VL_NEW || | |
459 | vl->state == AFS_VL_VALID || | |
460 | vl->state == AFS_VL_NO_VOLUME); | |
461 | if (ret < 0) | |
462 | goto error; | |
463 | spin_lock(&vl->lock); | |
464 | } | |
465 | spin_unlock(&vl->lock); | |
466 | ||
467 | success: | |
468 | _leave(" = %p",vl); | |
469 | return vl; | |
470 | ||
471 | error_abandon: | |
472 | spin_lock(&vl->lock); | |
473 | vl->state = AFS_VL_NEW; | |
474 | spin_unlock(&vl->lock); | |
475 | wake_up(&vl->waitq); | |
476 | error: | |
477 | ASSERT(vl != NULL); | |
478 | afs_put_vlocation(vl); | |
479 | _leave(" = %d", ret); | |
480 | return ERR_PTR(ret); | |
481 | } | |
482 | ||
483 | /* | |
484 | * finish using a volume location record | |
485 | */ | |
486 | void afs_put_vlocation(struct afs_vlocation *vl) | |
487 | { | |
488 | if (!vl) | |
489 | return; | |
490 | ||
491 | _enter("%s", vl->vldb.name); | |
492 | ||
493 | ASSERTCMP(atomic_read(&vl->usage), >, 0); | |
494 | ||
495 | if (likely(!atomic_dec_and_test(&vl->usage))) { | |
496 | _leave(""); | |
497 | return; | |
498 | } | |
499 | ||
500 | spin_lock(&afs_vlocation_graveyard_lock); | |
501 | if (atomic_read(&vl->usage) == 0) { | |
502 | _debug("buried"); | |
503 | list_move_tail(&vl->grave, &afs_vlocation_graveyard); | |
504 | vl->time_of_death = get_seconds(); | |
505 | schedule_delayed_work(&afs_vlocation_reap, | |
506 | afs_vlocation_timeout * HZ); | |
507 | ||
508 | /* suspend updates on this record */ | |
509 | if (!list_empty(&vl->update)) { | |
510 | spin_lock(&afs_vlocation_updates_lock); | |
511 | list_del_init(&vl->update); | |
512 | spin_unlock(&afs_vlocation_updates_lock); | |
513 | } | |
514 | } | |
515 | spin_unlock(&afs_vlocation_graveyard_lock); | |
516 | _leave(" [killed?]"); | |
517 | } | |
518 | ||
519 | /* | |
520 | * destroy a dead volume location record | |
521 | */ | |
522 | static void afs_vlocation_destroy(struct afs_vlocation *vl) | |
523 | { | |
524 | _enter("%p", vl); | |
525 | ||
526 | #ifdef AFS_CACHING_SUPPORT | |
527 | cachefs_relinquish_cookie(vl->cache, 0); | |
528 | #endif | |
529 | ||
530 | afs_put_cell(vl->cell); | |
531 | kfree(vl); | |
532 | } | |
533 | ||
534 | /* | |
535 | * reap dead volume location records | |
536 | */ | |
537 | static void afs_vlocation_reaper(struct work_struct *work) | |
538 | { | |
539 | LIST_HEAD(corpses); | |
540 | struct afs_vlocation *vl; | |
541 | unsigned long delay, expiry; | |
542 | time_t now; | |
543 | ||
544 | _enter(""); | |
545 | ||
546 | now = get_seconds(); | |
547 | spin_lock(&afs_vlocation_graveyard_lock); | |
548 | ||
549 | while (!list_empty(&afs_vlocation_graveyard)) { | |
550 | vl = list_entry(afs_vlocation_graveyard.next, | |
551 | struct afs_vlocation, grave); | |
552 | ||
553 | _debug("check %p", vl); | |
554 | ||
555 | /* the queue is ordered most dead first */ | |
556 | expiry = vl->time_of_death + afs_vlocation_timeout; | |
557 | if (expiry > now) { | |
558 | delay = (expiry - now) * HZ; | |
559 | _debug("delay %lu", delay); | |
560 | if (!schedule_delayed_work(&afs_vlocation_reap, | |
561 | delay)) { | |
562 | cancel_delayed_work(&afs_vlocation_reap); | |
563 | schedule_delayed_work(&afs_vlocation_reap, | |
564 | delay); | |
565 | } | |
566 | break; | |
567 | } | |
568 | ||
569 | spin_lock(&vl->cell->vl_lock); | |
570 | if (atomic_read(&vl->usage) > 0) { | |
571 | _debug("no reap"); | |
572 | list_del_init(&vl->grave); | |
573 | } else { | |
574 | _debug("reap"); | |
575 | list_move_tail(&vl->grave, &corpses); | |
576 | list_del_init(&vl->link); | |
577 | } | |
578 | spin_unlock(&vl->cell->vl_lock); | |
579 | } | |
580 | ||
581 | spin_unlock(&afs_vlocation_graveyard_lock); | |
582 | ||
583 | /* now reap the corpses we've extracted */ | |
584 | while (!list_empty(&corpses)) { | |
585 | vl = list_entry(corpses.next, struct afs_vlocation, grave); | |
586 | list_del(&vl->grave); | |
587 | afs_vlocation_destroy(vl); | |
588 | } | |
589 | ||
590 | _leave(""); | |
591 | } | |
592 | ||
593 | /* | |
594 | * initialise the VL update process | |
595 | */ | |
596 | int __init afs_vlocation_update_init(void) | |
597 | { | |
598 | afs_vlocation_update_worker = | |
599 | create_singlethread_workqueue("kafs_vlupdated"); | |
600 | return afs_vlocation_update_worker ? 0 : -ENOMEM; | |
601 | } | |
602 | ||
603 | /* | |
604 | * discard all the volume location records for rmmod | |
605 | */ | |
606 | void afs_vlocation_purge(void) | |
607 | { | |
608 | afs_vlocation_timeout = 0; | |
609 | ||
610 | spin_lock(&afs_vlocation_updates_lock); | |
611 | list_del_init(&afs_vlocation_updates); | |
612 | spin_unlock(&afs_vlocation_updates_lock); | |
613 | cancel_delayed_work(&afs_vlocation_update); | |
614 | queue_delayed_work(afs_vlocation_update_worker, | |
615 | &afs_vlocation_update, 0); | |
616 | destroy_workqueue(afs_vlocation_update_worker); | |
617 | ||
618 | cancel_delayed_work(&afs_vlocation_reap); | |
619 | schedule_delayed_work(&afs_vlocation_reap, 0); | |
620 | } | |
621 | ||
622 | /* | |
623 | * update a volume location | |
624 | */ | |
625 | static void afs_vlocation_updater(struct work_struct *work) | |
626 | { | |
627 | struct afs_cache_vlocation vldb; | |
628 | struct afs_vlocation *vl, *xvl; | |
629 | time_t now; | |
630 | long timeout; | |
631 | int ret; | |
632 | ||
633 | _enter(""); | |
634 | ||
635 | now = get_seconds(); | |
636 | ||
637 | /* find a record to update */ | |
638 | spin_lock(&afs_vlocation_updates_lock); | |
639 | for (;;) { | |
640 | if (list_empty(&afs_vlocation_updates)) { | |
641 | spin_unlock(&afs_vlocation_updates_lock); | |
642 | _leave(" [nothing]"); | |
643 | return; | |
644 | } | |
645 | ||
646 | vl = list_entry(afs_vlocation_updates.next, | |
647 | struct afs_vlocation, update); | |
648 | if (atomic_read(&vl->usage) > 0) | |
649 | break; | |
650 | list_del_init(&vl->update); | |
651 | } | |
652 | ||
653 | timeout = vl->update_at - now; | |
654 | if (timeout > 0) { | |
655 | queue_delayed_work(afs_vlocation_update_worker, | |
656 | &afs_vlocation_update, timeout * HZ); | |
657 | spin_unlock(&afs_vlocation_updates_lock); | |
658 | _leave(" [nothing]"); | |
659 | return; | |
660 | } | |
661 | ||
662 | list_del_init(&vl->update); | |
663 | atomic_inc(&vl->usage); | |
664 | spin_unlock(&afs_vlocation_updates_lock); | |
665 | ||
666 | /* we can now perform the update */ | |
667 | _debug("update %s", vl->vldb.name); | |
668 | vl->state = AFS_VL_UPDATING; | |
669 | vl->upd_rej_cnt = 0; | |
670 | vl->upd_busy_cnt = 0; | |
671 | ||
672 | ret = afs_vlocation_update_record(vl, NULL, &vldb); | |
673 | spin_lock(&vl->lock); | |
674 | switch (ret) { | |
675 | case 0: | |
676 | afs_vlocation_apply_update(vl, &vldb); | |
677 | vl->state = AFS_VL_VALID; | |
678 | break; | |
679 | case -ENOMEDIUM: | |
680 | vl->state = AFS_VL_VOLUME_DELETED; | |
681 | break; | |
682 | default: | |
683 | vl->state = AFS_VL_UNCERTAIN; | |
684 | break; | |
685 | } | |
686 | spin_unlock(&vl->lock); | |
687 | wake_up(&vl->waitq); | |
688 | ||
689 | /* and then reschedule */ | |
690 | _debug("reschedule"); | |
691 | vl->update_at = get_seconds() + afs_vlocation_update_timeout; | |
692 | ||
693 | spin_lock(&afs_vlocation_updates_lock); | |
694 | ||
695 | if (!list_empty(&afs_vlocation_updates)) { | |
696 | /* next update in 10 minutes, but wait at least 1 second more | |
697 | * than the newest record already queued so that we don't spam | |
698 | * the VL server suddenly with lots of requests | |
699 | */ | |
700 | xvl = list_entry(afs_vlocation_updates.prev, | |
701 | struct afs_vlocation, update); | |
702 | if (vl->update_at <= xvl->update_at) | |
703 | vl->update_at = xvl->update_at + 1; | |
704 | xvl = list_entry(afs_vlocation_updates.next, | |
705 | struct afs_vlocation, update); | |
706 | timeout = xvl->update_at - now; | |
707 | if (timeout < 0) | |
708 | timeout = 0; | |
709 | } else { | |
710 | timeout = afs_vlocation_update_timeout; | |
711 | } | |
712 | ||
713 | ASSERT(list_empty(&vl->update)); | |
714 | ||
715 | list_add_tail(&vl->update, &afs_vlocation_updates); | |
716 | ||
717 | _debug("timeout %ld", timeout); | |
718 | queue_delayed_work(afs_vlocation_update_worker, | |
719 | &afs_vlocation_update, timeout * HZ); | |
720 | spin_unlock(&afs_vlocation_updates_lock); | |
721 | afs_put_vlocation(vl); | |
722 | } |