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1// SPDX-License-Identifier: GPL-2.0-or-later
2/* AFS cell and server record management
3 *
4 * Copyright (C) 2002, 2017 Red Hat, Inc. All Rights Reserved.
5 * Written by David Howells ([email protected])
6 */
7
8#include <linux/slab.h>
9#include <linux/key.h>
10#include <linux/ctype.h>
11#include <linux/dns_resolver.h>
12#include <linux/sched.h>
13#include <linux/inet.h>
14#include <linux/namei.h>
15#include <keys/rxrpc-type.h>
16#include "internal.h"
17
18static unsigned __read_mostly afs_cell_gc_delay = 10;
19static unsigned __read_mostly afs_cell_min_ttl = 10 * 60;
20static unsigned __read_mostly afs_cell_max_ttl = 24 * 60 * 60;
21static atomic_t cell_debug_id;
22
23static void afs_cell_timer(struct timer_list *timer);
24static void afs_destroy_cell_work(struct work_struct *work);
25static void afs_manage_cell_work(struct work_struct *work);
26
27static void afs_dec_cells_outstanding(struct afs_net *net)
28{
29 if (atomic_dec_and_test(&net->cells_outstanding))
30 wake_up_var(&net->cells_outstanding);
31}
32
33static void afs_set_cell_state(struct afs_cell *cell, enum afs_cell_state state)
34{
35 smp_store_release(&cell->state, state); /* Commit cell changes before state */
36 smp_wmb(); /* Set cell state before task state */
37 wake_up_var(&cell->state);
38}
39
40/*
41 * Look up and get an activation reference on a cell record. The caller must
42 * hold net->cells_lock at least read-locked.
43 */
44static struct afs_cell *afs_find_cell_locked(struct afs_net *net,
45 const char *name, unsigned int namesz,
46 enum afs_cell_trace reason)
47{
48 struct afs_cell *cell = NULL;
49 struct rb_node *p;
50 int n;
51
52 _enter("%*.*s", namesz, namesz, name);
53
54 if (name && namesz == 0)
55 return ERR_PTR(-EINVAL);
56 if (namesz > AFS_MAXCELLNAME)
57 return ERR_PTR(-ENAMETOOLONG);
58
59 if (!name) {
60 cell = rcu_dereference_protected(net->ws_cell,
61 lockdep_is_held(&net->cells_lock));
62 if (!cell)
63 return ERR_PTR(-EDESTADDRREQ);
64 goto found;
65 }
66
67 p = net->cells.rb_node;
68 while (p) {
69 cell = rb_entry(p, struct afs_cell, net_node);
70
71 n = strncasecmp(cell->name, name,
72 min_t(size_t, cell->name_len, namesz));
73 if (n == 0)
74 n = cell->name_len - namesz;
75 if (n < 0)
76 p = p->rb_left;
77 else if (n > 0)
78 p = p->rb_right;
79 else
80 goto found;
81 }
82
83 return ERR_PTR(-ENOENT);
84
85found:
86 return afs_use_cell(cell, reason);
87}
88
89/*
90 * Look up and get an activation reference on a cell record.
91 */
92struct afs_cell *afs_find_cell(struct afs_net *net,
93 const char *name, unsigned int namesz,
94 enum afs_cell_trace reason)
95{
96 struct afs_cell *cell;
97
98 down_read(&net->cells_lock);
99 cell = afs_find_cell_locked(net, name, namesz, reason);
100 up_read(&net->cells_lock);
101 return cell;
102}
103
104/*
105 * Set up a cell record and fill in its name, VL server address list and
106 * allocate an anonymous key
107 */
108static struct afs_cell *afs_alloc_cell(struct afs_net *net,
109 const char *name, unsigned int namelen,
110 const char *addresses)
111{
112 struct afs_vlserver_list *vllist = NULL;
113 struct afs_cell *cell;
114 int i, ret;
115
116 ASSERT(name);
117 if (namelen == 0)
118 return ERR_PTR(-EINVAL);
119 if (namelen > AFS_MAXCELLNAME) {
120 _leave(" = -ENAMETOOLONG");
121 return ERR_PTR(-ENAMETOOLONG);
122 }
123
124 /* Prohibit cell names that contain unprintable chars, '/' and '@' or
125 * that begin with a dot. This also precludes "@cell".
126 */
127 if (name[0] == '.')
128 return ERR_PTR(-EINVAL);
129 for (i = 0; i < namelen; i++) {
130 char ch = name[i];
131 if (!isprint(ch) || ch == '/' || ch == '@')
132 return ERR_PTR(-EINVAL);
133 }
134
135 _enter("%*.*s,%s", namelen, namelen, name, addresses);
136
137 cell = kzalloc_obj(struct afs_cell);
138 if (!cell) {
139 _leave(" = -ENOMEM");
140 return ERR_PTR(-ENOMEM);
141 }
142
143 /* Allocate the cell name and the key name in one go. */
144 cell->name = kmalloc(1 + namelen + 1 +
145 4 + namelen + 1, GFP_KERNEL);
146 if (!cell->name) {
147 kfree(cell);
148 return ERR_PTR(-ENOMEM);
149 }
150
151 cell->name[0] = '.';
152 cell->name++;
153 cell->name_len = namelen;
154 for (i = 0; i < namelen; i++)
155 cell->name[i] = tolower(name[i]);
156 cell->name[i++] = 0;
157
158 cell->key_desc = cell->name + i;
159 memcpy(cell->key_desc, "afs@", 4);
160 memcpy(cell->key_desc + 4, cell->name, cell->name_len + 1);
161
162 cell->net = net;
163 refcount_set(&cell->ref, 1);
164 atomic_set(&cell->active, 0);
165 INIT_WORK(&cell->destroyer, afs_destroy_cell_work);
166 INIT_WORK(&cell->manager, afs_manage_cell_work);
167 timer_setup(&cell->management_timer, afs_cell_timer, 0);
168 init_rwsem(&cell->vs_lock);
169 cell->volumes = RB_ROOT;
170 INIT_HLIST_HEAD(&cell->proc_volumes);
171 seqlock_init(&cell->volume_lock);
172 cell->fs_servers = RB_ROOT;
173 init_rwsem(&cell->fs_lock);
174 rwlock_init(&cell->vl_servers_lock);
175 cell->flags = (1 << AFS_CELL_FL_CHECK_ALIAS);
176
177 /* Provide a VL server list, filling it in if we were given a list of
178 * addresses to use.
179 */
180 if (addresses) {
181 vllist = afs_parse_text_addrs(net,
182 addresses, strlen(addresses), ':',
183 VL_SERVICE, AFS_VL_PORT);
184 if (IS_ERR(vllist)) {
185 ret = PTR_ERR(vllist);
186 vllist = NULL;
187 goto parse_failed;
188 }
189
190 vllist->source = DNS_RECORD_FROM_CONFIG;
191 vllist->status = DNS_LOOKUP_NOT_DONE;
192 cell->dns_expiry = TIME64_MAX;
193 } else {
194 ret = -ENOMEM;
195 vllist = afs_alloc_vlserver_list(0);
196 if (!vllist)
197 goto error;
198 vllist->source = DNS_RECORD_UNAVAILABLE;
199 vllist->status = DNS_LOOKUP_NOT_DONE;
200 cell->dns_expiry = ktime_get_real_seconds();
201 }
202
203 rcu_assign_pointer(cell->vl_servers, vllist);
204
205 cell->dns_source = vllist->source;
206 cell->dns_status = vllist->status;
207 smp_store_release(&cell->dns_lookup_count, 1); /* vs source/status */
208 atomic_inc(&net->cells_outstanding);
209 cell->debug_id = atomic_inc_return(&cell_debug_id);
210
211 trace_afs_cell(cell->debug_id, 1, 0, afs_cell_trace_alloc);
212
213 _leave(" = %p", cell);
214 return cell;
215
216parse_failed:
217 if (ret == -EINVAL)
218 printk(KERN_ERR "kAFS: bad VL server IP address\n");
219error:
220 afs_put_vlserverlist(cell->net, vllist);
221 kfree(cell->name - 1);
222 kfree(cell);
223 _leave(" = %d", ret);
224 return ERR_PTR(ret);
225}
226
227/*
228 * afs_lookup_cell - Look up or create a cell record.
229 * @net: The network namespace
230 * @name: The name of the cell.
231 * @namesz: The strlen of the cell name.
232 * @vllist: A colon/comma separated list of numeric IP addresses or NULL.
233 * @reason: The reason we're doing the lookup
234 * @trace: The reason to be logged if the lookup is successful.
235 *
236 * Look up a cell record by name and query the DNS for VL server addresses if
237 * needed. Note that that actual DNS query is punted off to the manager thread
238 * so that this function can return immediately if interrupted whilst allowing
239 * cell records to be shared even if not yet fully constructed.
240 */
241struct afs_cell *afs_lookup_cell(struct afs_net *net,
242 const char *name, unsigned int namesz,
243 const char *vllist,
244 enum afs_lookup_cell_for reason,
245 enum afs_cell_trace trace)
246{
247 struct afs_cell *cell, *candidate, *cursor;
248 struct rb_node *parent, **pp;
249 enum afs_cell_state state;
250 int ret, n;
251
252 _enter("%s,%s,%u", name, vllist, reason);
253
254 if (reason != AFS_LOOKUP_CELL_PRELOAD) {
255 cell = afs_find_cell(net, name, namesz, trace);
256 if (!IS_ERR(cell)) {
257 if (reason == AFS_LOOKUP_CELL_DYNROOT)
258 goto no_wait;
259 if (cell->state == AFS_CELL_SETTING_UP ||
260 cell->state == AFS_CELL_UNLOOKED)
261 goto lookup_cell;
262 goto wait_for_cell;
263 }
264 }
265
266 /* Assume we're probably going to create a cell and preallocate and
267 * mostly set up a candidate record. We can then use this to stash the
268 * name, the net namespace and VL server addresses.
269 *
270 * We also want to do this before we hold any locks as it may involve
271 * upcalling to userspace to make DNS queries.
272 */
273 candidate = afs_alloc_cell(net, name, namesz, vllist);
274 if (IS_ERR(candidate)) {
275 _leave(" = %ld", PTR_ERR(candidate));
276 return candidate;
277 }
278
279 /* Find the insertion point and check to see if someone else added a
280 * cell whilst we were allocating.
281 */
282 down_write(&net->cells_lock);
283
284 pp = &net->cells.rb_node;
285 parent = NULL;
286 while (*pp) {
287 parent = *pp;
288 cursor = rb_entry(parent, struct afs_cell, net_node);
289
290 n = strncasecmp(cursor->name, name,
291 min_t(size_t, cursor->name_len, namesz));
292 if (n == 0)
293 n = cursor->name_len - namesz;
294 if (n < 0)
295 pp = &(*pp)->rb_left;
296 else if (n > 0)
297 pp = &(*pp)->rb_right;
298 else
299 goto cell_already_exists;
300 }
301
302 ret = idr_alloc_cyclic(&net->cells_dyn_ino, candidate,
303 2, INT_MAX / 2, GFP_KERNEL);
304 if (ret < 0)
305 goto cant_alloc_ino;
306 candidate->dynroot_ino = ret;
307 set_bit(AFS_CELL_FL_HAVE_INO, &candidate->flags);
308
309 cell = candidate;
310 candidate = NULL;
311 afs_use_cell(cell, trace);
312 rb_link_node_rcu(&cell->net_node, parent, pp);
313 rb_insert_color(&cell->net_node, &net->cells);
314 up_write(&net->cells_lock);
315
316lookup_cell:
317 if (reason != AFS_LOOKUP_CELL_PRELOAD &&
318 reason != AFS_LOOKUP_CELL_ROOTCELL) {
319 set_bit(AFS_CELL_FL_DO_LOOKUP, &cell->flags);
320 afs_queue_cell(cell, afs_cell_trace_queue_new);
321 }
322
323wait_for_cell:
324 state = smp_load_acquire(&cell->state); /* vs error */
325 switch (state) {
326 case AFS_CELL_ACTIVE:
327 case AFS_CELL_DEAD:
328 break;
329 case AFS_CELL_UNLOOKED:
330 default:
331 if (reason == AFS_LOOKUP_CELL_PRELOAD ||
332 reason == AFS_LOOKUP_CELL_ROOTCELL)
333 break;
334 _debug("wait_for_cell");
335 afs_see_cell(cell, afs_cell_trace_wait);
336 wait_var_event(&cell->state,
337 ({
338 state = smp_load_acquire(&cell->state); /* vs error */
339 state == AFS_CELL_ACTIVE || state == AFS_CELL_DEAD;
340 }));
341 _debug("waited_for_cell %d %d", cell->state, cell->error);
342 }
343
344no_wait:
345 /* Check the state obtained from the wait check. */
346 state = smp_load_acquire(&cell->state); /* vs error */
347 if (state == AFS_CELL_DEAD) {
348 ret = cell->error;
349 goto error;
350 }
351 if (state == AFS_CELL_ACTIVE) {
352 switch (cell->dns_status) {
353 case DNS_LOOKUP_NOT_DONE:
354 if (cell->dns_source == DNS_RECORD_FROM_CONFIG) {
355 ret = 0;
356 break;
357 }
358 fallthrough;
359 default:
360 ret = -EIO;
361 goto error;
362 case DNS_LOOKUP_GOOD:
363 case DNS_LOOKUP_GOOD_WITH_BAD:
364 ret = 0;
365 break;
366 case DNS_LOOKUP_GOT_NOT_FOUND:
367 ret = -ENOENT;
368 goto error;
369 case DNS_LOOKUP_BAD:
370 ret = -EREMOTEIO;
371 goto error;
372 case DNS_LOOKUP_GOT_LOCAL_FAILURE:
373 case DNS_LOOKUP_GOT_TEMP_FAILURE:
374 case DNS_LOOKUP_GOT_NS_FAILURE:
375 ret = -EDESTADDRREQ;
376 goto error;
377 }
378 }
379
380 _leave(" = %p [cell]", cell);
381 return cell;
382
383cant_alloc_ino:
384 up_write(&net->cells_lock);
385 afs_put_cell(candidate, afs_cell_trace_put_candidate);
386 goto error_noput;
387
388cell_already_exists:
389 _debug("cell exists");
390 cell = cursor;
391 if (reason == AFS_LOOKUP_CELL_PRELOAD) {
392 ret = -EEXIST;
393 } else {
394 afs_use_cell(cursor, trace);
395 ret = 0;
396 }
397 up_write(&net->cells_lock);
398 if (candidate)
399 afs_put_cell(candidate, afs_cell_trace_put_candidate);
400 if (ret == 0)
401 goto wait_for_cell;
402 goto error_noput;
403error:
404 afs_unuse_cell(cell, afs_cell_trace_unuse_lookup_error);
405error_noput:
406 _leave(" = %d [error]", ret);
407 return ERR_PTR(ret);
408}
409
410/*
411 * set the root cell information
412 * - can be called with a module parameter string
413 * - can be called from a write to /proc/fs/afs/rootcell
414 */
415int afs_cell_init(struct afs_net *net, const char *rootcell)
416{
417 struct afs_cell *old_root, *new_root;
418 const char *cp, *vllist;
419 size_t len;
420
421 _enter("");
422
423 if (!rootcell) {
424 /* module is loaded with no parameters, or built statically.
425 * - in the future we might initialize cell DB here.
426 */
427 _leave(" = 0 [no root]");
428 return 0;
429 }
430
431 cp = strchr(rootcell, ':');
432 if (!cp) {
433 _debug("kAFS: no VL server IP addresses specified");
434 vllist = NULL;
435 len = strlen(rootcell);
436 } else {
437 vllist = cp + 1;
438 len = cp - rootcell;
439 }
440
441 if (len == 0 || !rootcell[0] || rootcell[0] == '.' || rootcell[len - 1] == '.')
442 return -EINVAL;
443 if (memchr(rootcell, '/', len))
444 return -EINVAL;
445 cp = strstr(rootcell, "..");
446 if (cp && cp < rootcell + len)
447 return -EINVAL;
448
449 /* allocate a cell record for the root/workstation cell */
450 new_root = afs_lookup_cell(net, rootcell, len, vllist,
451 AFS_LOOKUP_CELL_ROOTCELL,
452 afs_cell_trace_use_lookup_ws);
453 if (IS_ERR(new_root)) {
454 _leave(" = %ld", PTR_ERR(new_root));
455 return PTR_ERR(new_root);
456 }
457
458 if (!test_and_set_bit(AFS_CELL_FL_NO_GC, &new_root->flags))
459 afs_use_cell(new_root, afs_cell_trace_use_pin);
460
461 /* install the new cell */
462 down_write(&net->cells_lock);
463 old_root = rcu_replace_pointer(net->ws_cell, new_root,
464 lockdep_is_held(&net->cells_lock));
465 up_write(&net->cells_lock);
466
467 afs_unuse_cell(old_root, afs_cell_trace_unuse_ws);
468 _leave(" = 0");
469 return 0;
470}
471
472/*
473 * Update a cell's VL server address list from the DNS.
474 */
475static int afs_update_cell(struct afs_cell *cell)
476{
477 struct afs_vlserver_list *vllist, *old = NULL, *p;
478 unsigned int min_ttl = READ_ONCE(afs_cell_min_ttl);
479 unsigned int max_ttl = READ_ONCE(afs_cell_max_ttl);
480 time64_t now, expiry = 0;
481 int ret = 0;
482
483 _enter("%s", cell->name);
484
485 vllist = afs_dns_query(cell, &expiry);
486 if (IS_ERR(vllist)) {
487 ret = PTR_ERR(vllist);
488
489 _debug("%s: fail %d", cell->name, ret);
490 if (ret == -ENOMEM)
491 goto out_wake;
492
493 vllist = afs_alloc_vlserver_list(0);
494 if (!vllist) {
495 if (ret >= 0)
496 ret = -ENOMEM;
497 goto out_wake;
498 }
499
500 switch (ret) {
501 case -ENODATA:
502 case -EDESTADDRREQ:
503 vllist->status = DNS_LOOKUP_GOT_NOT_FOUND;
504 break;
505 case -EAGAIN:
506 case -ECONNREFUSED:
507 vllist->status = DNS_LOOKUP_GOT_TEMP_FAILURE;
508 break;
509 default:
510 vllist->status = DNS_LOOKUP_GOT_LOCAL_FAILURE;
511 break;
512 }
513 }
514
515 _debug("%s: got list %d %d", cell->name, vllist->source, vllist->status);
516 cell->dns_status = vllist->status;
517
518 now = ktime_get_real_seconds();
519 if (min_ttl > max_ttl)
520 max_ttl = min_ttl;
521 if (expiry < now + min_ttl)
522 expiry = now + min_ttl;
523 else if (expiry > now + max_ttl)
524 expiry = now + max_ttl;
525
526 _debug("%s: status %d", cell->name, vllist->status);
527 if (vllist->source == DNS_RECORD_UNAVAILABLE) {
528 switch (vllist->status) {
529 case DNS_LOOKUP_GOT_NOT_FOUND:
530 /* The DNS said that the cell does not exist or there
531 * weren't any addresses to be had.
532 */
533 cell->dns_expiry = expiry;
534 break;
535
536 case DNS_LOOKUP_BAD:
537 case DNS_LOOKUP_GOT_LOCAL_FAILURE:
538 case DNS_LOOKUP_GOT_TEMP_FAILURE:
539 case DNS_LOOKUP_GOT_NS_FAILURE:
540 default:
541 cell->dns_expiry = now + 10;
542 break;
543 }
544 } else {
545 cell->dns_expiry = expiry;
546 }
547
548 /* Replace the VL server list if the new record has servers or the old
549 * record doesn't.
550 */
551 write_lock(&cell->vl_servers_lock);
552 p = rcu_dereference_protected(cell->vl_servers, true);
553 if (vllist->nr_servers > 0 || p->nr_servers == 0) {
554 rcu_assign_pointer(cell->vl_servers, vllist);
555 cell->dns_source = vllist->source;
556 old = p;
557 } else {
558 old = vllist;
559 }
560 write_unlock(&cell->vl_servers_lock);
561 afs_put_vlserverlist(cell->net, old);
562
563out_wake:
564 smp_store_release(&cell->dns_lookup_count,
565 cell->dns_lookup_count + 1); /* vs source/status */
566 wake_up_var(&cell->dns_lookup_count);
567 _leave(" = %d", ret);
568 return ret;
569}
570
571/*
572 * Destroy a cell record
573 */
574static void afs_cell_destroy(struct rcu_head *rcu)
575{
576 struct afs_cell *cell = container_of(rcu, struct afs_cell, rcu);
577 struct afs_net *net = cell->net;
578 int r;
579
580 _enter("%p{%s}", cell, cell->name);
581
582 r = refcount_read(&cell->ref);
583 ASSERTCMP(r, ==, 0);
584 trace_afs_cell(cell->debug_id, r, atomic_read(&cell->active), afs_cell_trace_free);
585
586 afs_put_vlserverlist(net, rcu_access_pointer(cell->vl_servers));
587 afs_unuse_cell(cell->alias_of, afs_cell_trace_unuse_alias);
588 key_put(cell->anonymous_key);
589 kfree(cell->name - 1);
590 kfree(cell);
591
592 afs_dec_cells_outstanding(net);
593 _leave(" [destroyed]");
594}
595
596static void afs_destroy_cell_work(struct work_struct *work)
597{
598 struct afs_cell *cell = container_of(work, struct afs_cell, destroyer);
599
600 afs_see_cell(cell, afs_cell_trace_destroy);
601 timer_delete_sync(&cell->management_timer);
602 cancel_work_sync(&cell->manager);
603
604 if (test_bit(AFS_CELL_FL_HAVE_INO, &cell->flags)) {
605 down_write(&cell->net->cells_lock);
606 idr_remove(&cell->net->cells_dyn_ino, cell->dynroot_ino);
607 up_write(&cell->net->cells_lock);
608 }
609
610 call_rcu(&cell->rcu, afs_cell_destroy);
611}
612
613/*
614 * Get a reference on a cell record.
615 */
616struct afs_cell *afs_get_cell(struct afs_cell *cell, enum afs_cell_trace reason)
617{
618 int r;
619
620 __refcount_inc(&cell->ref, &r);
621 trace_afs_cell(cell->debug_id, r + 1, atomic_read(&cell->active), reason);
622 return cell;
623}
624
625/*
626 * Drop a reference on a cell record.
627 */
628void afs_put_cell(struct afs_cell *cell, enum afs_cell_trace reason)
629{
630 if (cell) {
631 unsigned int debug_id = cell->debug_id;
632 unsigned int a;
633 bool zero;
634 int r;
635
636 a = atomic_read(&cell->active);
637 zero = __refcount_dec_and_test(&cell->ref, &r);
638 trace_afs_cell(debug_id, r - 1, a, reason);
639 if (zero) {
640 a = atomic_read(&cell->active);
641 WARN(a != 0, "Cell active count %u > 0\n", a);
642 WARN_ON(!queue_work(afs_wq, &cell->destroyer));
643 }
644 }
645}
646
647/*
648 * Note a cell becoming more active.
649 */
650struct afs_cell *afs_use_cell(struct afs_cell *cell, enum afs_cell_trace reason)
651{
652 int r, a;
653
654 __refcount_inc(&cell->ref, &r);
655 a = atomic_inc_return(&cell->active);
656 trace_afs_cell(cell->debug_id, r + 1, a, reason);
657 return cell;
658}
659
660/*
661 * Record a cell becoming less active. When the active counter reaches 1, it
662 * is scheduled for destruction, but may get reactivated.
663 */
664void afs_unuse_cell(struct afs_cell *cell, enum afs_cell_trace reason)
665{
666 unsigned int debug_id;
667 time64_t now, expire_delay;
668 bool zero;
669 int r, a;
670
671 if (!cell)
672 return;
673
674 _enter("%s", cell->name);
675
676 now = ktime_get_real_seconds();
677 cell->last_inactive = now;
678 expire_delay = 0;
679 if (cell->vl_servers->nr_servers)
680 expire_delay = afs_cell_gc_delay;
681
682 debug_id = cell->debug_id;
683 a = atomic_dec_return(&cell->active);
684 if (!a)
685 /* 'cell' may now be garbage collected. */
686 afs_set_cell_timer(cell, expire_delay);
687
688 zero = __refcount_dec_and_test(&cell->ref, &r);
689 trace_afs_cell(debug_id, r - 1, a, reason);
690 if (zero)
691 WARN_ON(!queue_work(afs_wq, &cell->destroyer));
692}
693
694/*
695 * Note that a cell has been seen.
696 */
697void afs_see_cell(struct afs_cell *cell, enum afs_cell_trace reason)
698{
699 int r, a;
700
701 r = refcount_read(&cell->ref);
702 a = atomic_read(&cell->active);
703 trace_afs_cell(cell->debug_id, r, a, reason);
704}
705
706/*
707 * Queue a cell for management, giving the workqueue a ref to hold.
708 */
709void afs_queue_cell(struct afs_cell *cell, enum afs_cell_trace reason)
710{
711 queue_work(afs_wq, &cell->manager);
712}
713
714/*
715 * Cell-specific management timer.
716 */
717static void afs_cell_timer(struct timer_list *timer)
718{
719 struct afs_cell *cell = container_of(timer, struct afs_cell, management_timer);
720
721 afs_see_cell(cell, afs_cell_trace_see_mgmt_timer);
722 if (refcount_read(&cell->ref) > 0 && cell->net->live)
723 queue_work(afs_wq, &cell->manager);
724}
725
726/*
727 * Set/reduce the cell timer.
728 */
729void afs_set_cell_timer(struct afs_cell *cell, unsigned int delay_secs)
730{
731 timer_reduce(&cell->management_timer, jiffies + delay_secs * HZ);
732}
733
734/*
735 * Activate a cell.
736 */
737static int afs_activate_cell(struct afs_net *net, struct afs_cell *cell)
738{
739 struct hlist_node **p;
740 struct afs_cell *pcell;
741 int ret;
742
743 ret = afs_proc_cell_setup(cell);
744 if (ret < 0)
745 return ret;
746
747 mutex_lock(&net->proc_cells_lock);
748 for (p = &net->proc_cells.first; *p; p = &(*p)->next) {
749 pcell = hlist_entry(*p, struct afs_cell, proc_link);
750 if (strcmp(cell->name, pcell->name) < 0)
751 break;
752 }
753
754 cell->proc_link.pprev = p;
755 cell->proc_link.next = *p;
756 rcu_assign_pointer(*p, &cell->proc_link.next);
757 if (cell->proc_link.next)
758 cell->proc_link.next->pprev = &cell->proc_link.next;
759
760 mutex_unlock(&net->proc_cells_lock);
761 return 0;
762}
763
764/*
765 * Deactivate a cell.
766 */
767static void afs_deactivate_cell(struct afs_net *net, struct afs_cell *cell)
768{
769 _enter("%s", cell->name);
770
771 afs_proc_cell_remove(cell);
772
773 mutex_lock(&net->proc_cells_lock);
774 if (!hlist_unhashed(&cell->proc_link))
775 hlist_del_rcu(&cell->proc_link);
776 mutex_unlock(&net->proc_cells_lock);
777
778 _leave("");
779}
780
781static bool afs_has_cell_expired(struct afs_cell *cell, time64_t *_next_manage)
782{
783 const struct afs_vlserver_list *vllist;
784 time64_t expire_at = cell->last_inactive;
785 time64_t now = ktime_get_real_seconds();
786
787 if (atomic_read(&cell->active))
788 return false;
789 if (!cell->net->live)
790 return true;
791
792 vllist = rcu_dereference_protected(cell->vl_servers, true);
793 if (vllist && vllist->nr_servers > 0)
794 expire_at += afs_cell_gc_delay;
795
796 if (expire_at <= now)
797 return true;
798 if (expire_at < *_next_manage)
799 *_next_manage = expire_at;
800 return false;
801}
802
803/*
804 * Manage a cell record, initialising and destroying it, maintaining its DNS
805 * records.
806 */
807static bool afs_manage_cell(struct afs_cell *cell)
808{
809 struct afs_net *net = cell->net;
810 time64_t next_manage = TIME64_MAX;
811 int ret;
812
813 _enter("%s", cell->name);
814
815 _debug("state %u", cell->state);
816 switch (cell->state) {
817 case AFS_CELL_SETTING_UP:
818 goto set_up_cell;
819 case AFS_CELL_UNLOOKED:
820 case AFS_CELL_ACTIVE:
821 goto cell_is_active;
822 case AFS_CELL_REMOVING:
823 WARN_ON_ONCE(1);
824 return false;
825 case AFS_CELL_DEAD:
826 return false;
827 default:
828 _debug("bad state %u", cell->state);
829 WARN_ON_ONCE(1); /* Unhandled state */
830 return false;
831 }
832
833set_up_cell:
834 ret = afs_activate_cell(net, cell);
835 if (ret < 0) {
836 cell->error = ret;
837 goto remove_cell;
838 }
839
840 afs_set_cell_state(cell, AFS_CELL_UNLOOKED);
841
842cell_is_active:
843 if (afs_has_cell_expired(cell, &next_manage))
844 goto remove_cell;
845
846 if (test_and_clear_bit(AFS_CELL_FL_DO_LOOKUP, &cell->flags)) {
847 ret = afs_update_cell(cell);
848 if (ret < 0)
849 cell->error = ret;
850 if (cell->state == AFS_CELL_UNLOOKED)
851 afs_set_cell_state(cell, AFS_CELL_ACTIVE);
852 }
853
854 if (next_manage < TIME64_MAX && cell->net->live) {
855 time64_t now = ktime_get_real_seconds();
856
857 if (next_manage - now <= 0)
858 afs_queue_cell(cell, afs_cell_trace_queue_again);
859 else
860 afs_set_cell_timer(cell, next_manage - now);
861 }
862 _leave(" [done %u]", cell->state);
863 return false;
864
865remove_cell:
866 down_write(&net->cells_lock);
867
868 if (atomic_read(&cell->active)) {
869 up_write(&net->cells_lock);
870 goto cell_is_active;
871 }
872
873 /* Make sure that the expiring server records are going to see the fact
874 * that the cell is caput.
875 */
876 afs_set_cell_state(cell, AFS_CELL_REMOVING);
877
878 afs_deactivate_cell(net, cell);
879 afs_purge_servers(cell);
880
881 rb_erase(&cell->net_node, &net->cells);
882 afs_see_cell(cell, afs_cell_trace_unuse_delete);
883 up_write(&net->cells_lock);
884
885 /* The root volume is pinning the cell */
886 afs_put_volume(cell->root_volume, afs_volume_trace_put_cell_root);
887 cell->root_volume = NULL;
888
889 afs_set_cell_state(cell, AFS_CELL_DEAD);
890 return true;
891}
892
893static void afs_manage_cell_work(struct work_struct *work)
894{
895 struct afs_cell *cell = container_of(work, struct afs_cell, manager);
896 bool final_put;
897
898 afs_see_cell(cell, afs_cell_trace_manage);
899 final_put = afs_manage_cell(cell);
900 afs_see_cell(cell, afs_cell_trace_managed);
901 if (final_put)
902 afs_put_cell(cell, afs_cell_trace_put_final);
903}
904
905/*
906 * Purge in-memory cell database.
907 */
908void afs_cell_purge(struct afs_net *net)
909{
910 struct afs_cell *ws;
911 struct rb_node *cursor;
912
913 _enter("");
914
915 down_write(&net->cells_lock);
916 ws = rcu_replace_pointer(net->ws_cell, NULL,
917 lockdep_is_held(&net->cells_lock));
918 up_write(&net->cells_lock);
919 afs_unuse_cell(ws, afs_cell_trace_unuse_ws);
920
921 _debug("kick cells");
922 down_read(&net->cells_lock);
923 for (cursor = rb_first(&net->cells); cursor; cursor = rb_next(cursor)) {
924 struct afs_cell *cell = rb_entry(cursor, struct afs_cell, net_node);
925
926 afs_see_cell(cell, afs_cell_trace_purge);
927
928 if (test_and_clear_bit(AFS_CELL_FL_NO_GC, &cell->flags))
929 afs_unuse_cell(cell, afs_cell_trace_unuse_pin);
930
931 afs_queue_cell(cell, afs_cell_trace_queue_purge);
932 }
933 up_read(&net->cells_lock);
934
935 _debug("wait");
936 wait_var_event(&net->cells_outstanding,
937 !atomic_read(&net->cells_outstanding));
938 _leave("");
939}