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1// SPDX-License-Identifier: GPL-2.0-or-later2/* AFS cell and server record management3 *4 * Copyright (C) 2002, 2017 Red Hat, Inc. All Rights Reserved.5 * Written by David Howells (dhowells@redhat.com)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_queue_cell_manager(struct afs_net *);24static void afs_manage_cell_work(struct work_struct *);25 26static void afs_dec_cells_outstanding(struct afs_net *net)27{28 if (atomic_dec_and_test(&net->cells_outstanding))29 wake_up_var(&net->cells_outstanding);30}31 32/*33 * Set the cell timer to fire after a given delay, assuming it's not already34 * set for an earlier time.35 */36static void afs_set_cell_timer(struct afs_net *net, time64_t delay)37{38 if (net->live) {39 atomic_inc(&net->cells_outstanding);40 if (timer_reduce(&net->cells_timer, jiffies + delay * HZ))41 afs_dec_cells_outstanding(net);42 } else {43 afs_queue_cell_manager(net);44 }45}46 47/*48 * Look up and get an activation reference on a cell record. The caller must49 * hold net->cells_lock at least read-locked.50 */51static struct afs_cell *afs_find_cell_locked(struct afs_net *net,52 const char *name, unsigned int namesz,53 enum afs_cell_trace reason)54{55 struct afs_cell *cell = NULL;56 struct rb_node *p;57 int n;58 59 _enter("%*.*s", namesz, namesz, name);60 61 if (name && namesz == 0)62 return ERR_PTR(-EINVAL);63 if (namesz > AFS_MAXCELLNAME)64 return ERR_PTR(-ENAMETOOLONG);65 66 if (!name) {67 cell = net->ws_cell;68 if (!cell)69 return ERR_PTR(-EDESTADDRREQ);70 goto found;71 }72 73 p = net->cells.rb_node;74 while (p) {75 cell = rb_entry(p, struct afs_cell, net_node);76 77 n = strncasecmp(cell->name, name,78 min_t(size_t, cell->name_len, namesz));79 if (n == 0)80 n = cell->name_len - namesz;81 if (n < 0)82 p = p->rb_left;83 else if (n > 0)84 p = p->rb_right;85 else86 goto found;87 }88 89 return ERR_PTR(-ENOENT);90 91found:92 return afs_use_cell(cell, reason);93}94 95/*96 * Look up and get an activation reference on a cell record.97 */98struct afs_cell *afs_find_cell(struct afs_net *net,99 const char *name, unsigned int namesz,100 enum afs_cell_trace reason)101{102 struct afs_cell *cell;103 104 down_read(&net->cells_lock);105 cell = afs_find_cell_locked(net, name, namesz, reason);106 up_read(&net->cells_lock);107 return cell;108}109 110/*111 * Set up a cell record and fill in its name, VL server address list and112 * allocate an anonymous key113 */114static struct afs_cell *afs_alloc_cell(struct afs_net *net,115 const char *name, unsigned int namelen,116 const char *addresses)117{118 struct afs_vlserver_list *vllist;119 struct afs_cell *cell;120 int i, ret;121 122 ASSERT(name);123 if (namelen == 0)124 return ERR_PTR(-EINVAL);125 if (namelen > AFS_MAXCELLNAME) {126 _leave(" = -ENAMETOOLONG");127 return ERR_PTR(-ENAMETOOLONG);128 }129 130 /* Prohibit cell names that contain unprintable chars, '/' and '@' or131 * that begin with a dot. This also precludes "@cell".132 */133 if (name[0] == '.')134 return ERR_PTR(-EINVAL);135 for (i = 0; i < namelen; i++) {136 char ch = name[i];137 if (!isprint(ch) || ch == '/' || ch == '@')138 return ERR_PTR(-EINVAL);139 }140 141 _enter("%*.*s,%s", namelen, namelen, name, addresses);142 143 cell = kzalloc(sizeof(struct afs_cell), GFP_KERNEL);144 if (!cell) {145 _leave(" = -ENOMEM");146 return ERR_PTR(-ENOMEM);147 }148 149 cell->name = kmalloc(namelen + 1, GFP_KERNEL);150 if (!cell->name) {151 kfree(cell);152 return ERR_PTR(-ENOMEM);153 }154 155 cell->net = net;156 cell->name_len = namelen;157 for (i = 0; i < namelen; i++)158 cell->name[i] = tolower(name[i]);159 cell->name[i] = 0;160 161 refcount_set(&cell->ref, 1);162 atomic_set(&cell->active, 0);163 INIT_WORK(&cell->manager, afs_manage_cell_work);164 init_rwsem(&cell->vs_lock);165 cell->volumes = RB_ROOT;166 INIT_HLIST_HEAD(&cell->proc_volumes);167 seqlock_init(&cell->volume_lock);168 cell->fs_servers = RB_ROOT;169 seqlock_init(&cell->fs_lock);170 rwlock_init(&cell->vl_servers_lock);171 cell->flags = (1 << AFS_CELL_FL_CHECK_ALIAS);172 173 /* Provide a VL server list, filling it in if we were given a list of174 * addresses to use.175 */176 if (addresses) {177 vllist = afs_parse_text_addrs(net,178 addresses, strlen(addresses), ':',179 VL_SERVICE, AFS_VL_PORT);180 if (IS_ERR(vllist)) {181 ret = PTR_ERR(vllist);182 goto parse_failed;183 }184 185 vllist->source = DNS_RECORD_FROM_CONFIG;186 vllist->status = DNS_LOOKUP_NOT_DONE;187 cell->dns_expiry = TIME64_MAX;188 } else {189 ret = -ENOMEM;190 vllist = afs_alloc_vlserver_list(0);191 if (!vllist)192 goto error;193 vllist->source = DNS_RECORD_UNAVAILABLE;194 vllist->status = DNS_LOOKUP_NOT_DONE;195 cell->dns_expiry = ktime_get_real_seconds();196 }197 198 rcu_assign_pointer(cell->vl_servers, vllist);199 200 cell->dns_source = vllist->source;201 cell->dns_status = vllist->status;202 smp_store_release(&cell->dns_lookup_count, 1); /* vs source/status */203 atomic_inc(&net->cells_outstanding);204 cell->debug_id = atomic_inc_return(&cell_debug_id);205 trace_afs_cell(cell->debug_id, 1, 0, afs_cell_trace_alloc);206 207 _leave(" = %p", cell);208 return cell;209 210parse_failed:211 if (ret == -EINVAL)212 printk(KERN_ERR "kAFS: bad VL server IP address\n");213error:214 kfree(cell->name);215 kfree(cell);216 _leave(" = %d", ret);217 return ERR_PTR(ret);218}219 220/*221 * afs_lookup_cell - Look up or create a cell record.222 * @net: The network namespace223 * @name: The name of the cell.224 * @namesz: The strlen of the cell name.225 * @vllist: A colon/comma separated list of numeric IP addresses or NULL.226 * @excl: T if an error should be given if the cell name already exists.227 *228 * Look up a cell record by name and query the DNS for VL server addresses if229 * needed. Note that that actual DNS query is punted off to the manager thread230 * so that this function can return immediately if interrupted whilst allowing231 * cell records to be shared even if not yet fully constructed.232 */233struct afs_cell *afs_lookup_cell(struct afs_net *net,234 const char *name, unsigned int namesz,235 const char *vllist, bool excl)236{237 struct afs_cell *cell, *candidate, *cursor;238 struct rb_node *parent, **pp;239 enum afs_cell_state state;240 int ret, n;241 242 _enter("%s,%s", name, vllist);243 244 if (!excl) {245 cell = afs_find_cell(net, name, namesz, afs_cell_trace_use_lookup);246 if (!IS_ERR(cell))247 goto wait_for_cell;248 }249 250 /* Assume we're probably going to create a cell and preallocate and251 * mostly set up a candidate record. We can then use this to stash the252 * name, the net namespace and VL server addresses.253 *254 * We also want to do this before we hold any locks as it may involve255 * upcalling to userspace to make DNS queries.256 */257 candidate = afs_alloc_cell(net, name, namesz, vllist);258 if (IS_ERR(candidate)) {259 _leave(" = %ld", PTR_ERR(candidate));260 return candidate;261 }262 263 /* Find the insertion point and check to see if someone else added a264 * cell whilst we were allocating.265 */266 down_write(&net->cells_lock);267 268 pp = &net->cells.rb_node;269 parent = NULL;270 while (*pp) {271 parent = *pp;272 cursor = rb_entry(parent, struct afs_cell, net_node);273 274 n = strncasecmp(cursor->name, name,275 min_t(size_t, cursor->name_len, namesz));276 if (n == 0)277 n = cursor->name_len - namesz;278 if (n < 0)279 pp = &(*pp)->rb_left;280 else if (n > 0)281 pp = &(*pp)->rb_right;282 else283 goto cell_already_exists;284 }285 286 cell = candidate;287 candidate = NULL;288 atomic_set(&cell->active, 2);289 trace_afs_cell(cell->debug_id, refcount_read(&cell->ref), 2, afs_cell_trace_insert);290 rb_link_node_rcu(&cell->net_node, parent, pp);291 rb_insert_color(&cell->net_node, &net->cells);292 up_write(&net->cells_lock);293 294 afs_queue_cell(cell, afs_cell_trace_get_queue_new);295 296wait_for_cell:297 trace_afs_cell(cell->debug_id, refcount_read(&cell->ref), atomic_read(&cell->active),298 afs_cell_trace_wait);299 _debug("wait_for_cell");300 wait_var_event(&cell->state,301 ({302 state = smp_load_acquire(&cell->state); /* vs error */303 state == AFS_CELL_ACTIVE || state == AFS_CELL_REMOVED;304 }));305 306 /* Check the state obtained from the wait check. */307 if (state == AFS_CELL_REMOVED) {308 ret = cell->error;309 goto error;310 }311 312 _leave(" = %p [cell]", cell);313 return cell;314 315cell_already_exists:316 _debug("cell exists");317 cell = cursor;318 if (excl) {319 ret = -EEXIST;320 } else {321 afs_use_cell(cursor, afs_cell_trace_use_lookup);322 ret = 0;323 }324 up_write(&net->cells_lock);325 if (candidate)326 afs_put_cell(candidate, afs_cell_trace_put_candidate);327 if (ret == 0)328 goto wait_for_cell;329 goto error_noput;330error:331 afs_unuse_cell(net, cell, afs_cell_trace_unuse_lookup);332error_noput:333 _leave(" = %d [error]", ret);334 return ERR_PTR(ret);335}336 337/*338 * set the root cell information339 * - can be called with a module parameter string340 * - can be called from a write to /proc/fs/afs/rootcell341 */342int afs_cell_init(struct afs_net *net, const char *rootcell)343{344 struct afs_cell *old_root, *new_root;345 const char *cp, *vllist;346 size_t len;347 348 _enter("");349 350 if (!rootcell) {351 /* module is loaded with no parameters, or built statically.352 * - in the future we might initialize cell DB here.353 */354 _leave(" = 0 [no root]");355 return 0;356 }357 358 cp = strchr(rootcell, ':');359 if (!cp) {360 _debug("kAFS: no VL server IP addresses specified");361 vllist = NULL;362 len = strlen(rootcell);363 } else {364 vllist = cp + 1;365 len = cp - rootcell;366 }367 368 /* allocate a cell record for the root cell */369 new_root = afs_lookup_cell(net, rootcell, len, vllist, false);370 if (IS_ERR(new_root)) {371 _leave(" = %ld", PTR_ERR(new_root));372 return PTR_ERR(new_root);373 }374 375 if (!test_and_set_bit(AFS_CELL_FL_NO_GC, &new_root->flags))376 afs_use_cell(new_root, afs_cell_trace_use_pin);377 378 /* install the new cell */379 down_write(&net->cells_lock);380 afs_see_cell(new_root, afs_cell_trace_see_ws);381 old_root = net->ws_cell;382 net->ws_cell = new_root;383 up_write(&net->cells_lock);384 385 afs_unuse_cell(net, old_root, afs_cell_trace_unuse_ws);386 _leave(" = 0");387 return 0;388}389 390/*391 * Update a cell's VL server address list from the DNS.392 */393static int afs_update_cell(struct afs_cell *cell)394{395 struct afs_vlserver_list *vllist, *old = NULL, *p;396 unsigned int min_ttl = READ_ONCE(afs_cell_min_ttl);397 unsigned int max_ttl = READ_ONCE(afs_cell_max_ttl);398 time64_t now, expiry = 0;399 int ret = 0;400 401 _enter("%s", cell->name);402 403 vllist = afs_dns_query(cell, &expiry);404 if (IS_ERR(vllist)) {405 ret = PTR_ERR(vllist);406 407 _debug("%s: fail %d", cell->name, ret);408 if (ret == -ENOMEM)409 goto out_wake;410 411 vllist = afs_alloc_vlserver_list(0);412 if (!vllist) {413 if (ret >= 0)414 ret = -ENOMEM;415 goto out_wake;416 }417 418 switch (ret) {419 case -ENODATA:420 case -EDESTADDRREQ:421 vllist->status = DNS_LOOKUP_GOT_NOT_FOUND;422 break;423 case -EAGAIN:424 case -ECONNREFUSED:425 vllist->status = DNS_LOOKUP_GOT_TEMP_FAILURE;426 break;427 default:428 vllist->status = DNS_LOOKUP_GOT_LOCAL_FAILURE;429 break;430 }431 }432 433 _debug("%s: got list %d %d", cell->name, vllist->source, vllist->status);434 cell->dns_status = vllist->status;435 436 now = ktime_get_real_seconds();437 if (min_ttl > max_ttl)438 max_ttl = min_ttl;439 if (expiry < now + min_ttl)440 expiry = now + min_ttl;441 else if (expiry > now + max_ttl)442 expiry = now + max_ttl;443 444 _debug("%s: status %d", cell->name, vllist->status);445 if (vllist->source == DNS_RECORD_UNAVAILABLE) {446 switch (vllist->status) {447 case DNS_LOOKUP_GOT_NOT_FOUND:448 /* The DNS said that the cell does not exist or there449 * weren't any addresses to be had.450 */451 cell->dns_expiry = expiry;452 break;453 454 case DNS_LOOKUP_BAD:455 case DNS_LOOKUP_GOT_LOCAL_FAILURE:456 case DNS_LOOKUP_GOT_TEMP_FAILURE:457 case DNS_LOOKUP_GOT_NS_FAILURE:458 default:459 cell->dns_expiry = now + 10;460 break;461 }462 } else {463 cell->dns_expiry = expiry;464 }465 466 /* Replace the VL server list if the new record has servers or the old467 * record doesn't.468 */469 write_lock(&cell->vl_servers_lock);470 p = rcu_dereference_protected(cell->vl_servers, true);471 if (vllist->nr_servers > 0 || p->nr_servers == 0) {472 rcu_assign_pointer(cell->vl_servers, vllist);473 cell->dns_source = vllist->source;474 old = p;475 }476 write_unlock(&cell->vl_servers_lock);477 afs_put_vlserverlist(cell->net, old);478 479out_wake:480 smp_store_release(&cell->dns_lookup_count,481 cell->dns_lookup_count + 1); /* vs source/status */482 wake_up_var(&cell->dns_lookup_count);483 _leave(" = %d", ret);484 return ret;485}486 487/*488 * Destroy a cell record489 */490static void afs_cell_destroy(struct rcu_head *rcu)491{492 struct afs_cell *cell = container_of(rcu, struct afs_cell, rcu);493 struct afs_net *net = cell->net;494 int r;495 496 _enter("%p{%s}", cell, cell->name);497 498 r = refcount_read(&cell->ref);499 ASSERTCMP(r, ==, 0);500 trace_afs_cell(cell->debug_id, r, atomic_read(&cell->active), afs_cell_trace_free);501 502 afs_put_vlserverlist(net, rcu_access_pointer(cell->vl_servers));503 afs_unuse_cell(net, cell->alias_of, afs_cell_trace_unuse_alias);504 key_put(cell->anonymous_key);505 kfree(cell->name);506 kfree(cell);507 508 afs_dec_cells_outstanding(net);509 _leave(" [destroyed]");510}511 512/*513 * Queue the cell manager.514 */515static void afs_queue_cell_manager(struct afs_net *net)516{517 int outstanding = atomic_inc_return(&net->cells_outstanding);518 519 _enter("%d", outstanding);520 521 if (!queue_work(afs_wq, &net->cells_manager))522 afs_dec_cells_outstanding(net);523}524 525/*526 * Cell management timer. We have an increment on cells_outstanding that we527 * need to pass along to the work item.528 */529void afs_cells_timer(struct timer_list *timer)530{531 struct afs_net *net = container_of(timer, struct afs_net, cells_timer);532 533 _enter("");534 if (!queue_work(afs_wq, &net->cells_manager))535 afs_dec_cells_outstanding(net);536}537 538/*539 * Get a reference on a cell record.540 */541struct afs_cell *afs_get_cell(struct afs_cell *cell, enum afs_cell_trace reason)542{543 int r;544 545 __refcount_inc(&cell->ref, &r);546 trace_afs_cell(cell->debug_id, r + 1, atomic_read(&cell->active), reason);547 return cell;548}549 550/*551 * Drop a reference on a cell record.552 */553void afs_put_cell(struct afs_cell *cell, enum afs_cell_trace reason)554{555 if (cell) {556 unsigned int debug_id = cell->debug_id;557 unsigned int a;558 bool zero;559 int r;560 561 a = atomic_read(&cell->active);562 zero = __refcount_dec_and_test(&cell->ref, &r);563 trace_afs_cell(debug_id, r - 1, a, reason);564 if (zero) {565 a = atomic_read(&cell->active);566 WARN(a != 0, "Cell active count %u > 0\n", a);567 call_rcu(&cell->rcu, afs_cell_destroy);568 }569 }570}571 572/*573 * Note a cell becoming more active.574 */575struct afs_cell *afs_use_cell(struct afs_cell *cell, enum afs_cell_trace reason)576{577 int r, a;578 579 r = refcount_read(&cell->ref);580 WARN_ON(r == 0);581 a = atomic_inc_return(&cell->active);582 trace_afs_cell(cell->debug_id, r, a, reason);583 return cell;584}585 586/*587 * Record a cell becoming less active. When the active counter reaches 1, it588 * is scheduled for destruction, but may get reactivated.589 */590void afs_unuse_cell(struct afs_net *net, struct afs_cell *cell, enum afs_cell_trace reason)591{592 unsigned int debug_id;593 time64_t now, expire_delay;594 int r, a;595 596 if (!cell)597 return;598 599 _enter("%s", cell->name);600 601 now = ktime_get_real_seconds();602 cell->last_inactive = now;603 expire_delay = 0;604 if (cell->vl_servers->nr_servers)605 expire_delay = afs_cell_gc_delay;606 607 debug_id = cell->debug_id;608 r = refcount_read(&cell->ref);609 a = atomic_dec_return(&cell->active);610 trace_afs_cell(debug_id, r, a, reason);611 WARN_ON(a == 0);612 if (a == 1)613 /* 'cell' may now be garbage collected. */614 afs_set_cell_timer(net, expire_delay);615}616 617/*618 * Note that a cell has been seen.619 */620void afs_see_cell(struct afs_cell *cell, enum afs_cell_trace reason)621{622 int r, a;623 624 r = refcount_read(&cell->ref);625 a = atomic_read(&cell->active);626 trace_afs_cell(cell->debug_id, r, a, reason);627}628 629/*630 * Queue a cell for management, giving the workqueue a ref to hold.631 */632void afs_queue_cell(struct afs_cell *cell, enum afs_cell_trace reason)633{634 afs_get_cell(cell, reason);635 if (!queue_work(afs_wq, &cell->manager))636 afs_put_cell(cell, afs_cell_trace_put_queue_fail);637}638 639/*640 * Allocate a key to use as a placeholder for anonymous user security.641 */642static int afs_alloc_anon_key(struct afs_cell *cell)643{644 struct key *key;645 char keyname[4 + AFS_MAXCELLNAME + 1], *cp, *dp;646 647 /* Create a key to represent an anonymous user. */648 memcpy(keyname, "afs@", 4);649 dp = keyname + 4;650 cp = cell->name;651 do {652 *dp++ = tolower(*cp);653 } while (*cp++);654 655 key = rxrpc_get_null_key(keyname);656 if (IS_ERR(key))657 return PTR_ERR(key);658 659 cell->anonymous_key = key;660 661 _debug("anon key %p{%x}",662 cell->anonymous_key, key_serial(cell->anonymous_key));663 return 0;664}665 666/*667 * Activate a cell.668 */669static int afs_activate_cell(struct afs_net *net, struct afs_cell *cell)670{671 struct hlist_node **p;672 struct afs_cell *pcell;673 int ret;674 675 if (!cell->anonymous_key) {676 ret = afs_alloc_anon_key(cell);677 if (ret < 0)678 return ret;679 }680 681 ret = afs_proc_cell_setup(cell);682 if (ret < 0)683 return ret;684 685 mutex_lock(&net->proc_cells_lock);686 for (p = &net->proc_cells.first; *p; p = &(*p)->next) {687 pcell = hlist_entry(*p, struct afs_cell, proc_link);688 if (strcmp(cell->name, pcell->name) < 0)689 break;690 }691 692 cell->proc_link.pprev = p;693 cell->proc_link.next = *p;694 rcu_assign_pointer(*p, &cell->proc_link.next);695 if (cell->proc_link.next)696 cell->proc_link.next->pprev = &cell->proc_link.next;697 698 afs_dynroot_mkdir(net, cell);699 mutex_unlock(&net->proc_cells_lock);700 return 0;701}702 703/*704 * Deactivate a cell.705 */706static void afs_deactivate_cell(struct afs_net *net, struct afs_cell *cell)707{708 _enter("%s", cell->name);709 710 afs_proc_cell_remove(cell);711 712 mutex_lock(&net->proc_cells_lock);713 hlist_del_rcu(&cell->proc_link);714 afs_dynroot_rmdir(net, cell);715 mutex_unlock(&net->proc_cells_lock);716 717 _leave("");718}719 720/*721 * Manage a cell record, initialising and destroying it, maintaining its DNS722 * records.723 */724static void afs_manage_cell(struct afs_cell *cell)725{726 struct afs_net *net = cell->net;727 int ret, active;728 729 _enter("%s", cell->name);730 731again:732 _debug("state %u", cell->state);733 switch (cell->state) {734 case AFS_CELL_INACTIVE:735 case AFS_CELL_FAILED:736 down_write(&net->cells_lock);737 active = 1;738 if (atomic_try_cmpxchg_relaxed(&cell->active, &active, 0)) {739 rb_erase(&cell->net_node, &net->cells);740 trace_afs_cell(cell->debug_id, refcount_read(&cell->ref), 0,741 afs_cell_trace_unuse_delete);742 smp_store_release(&cell->state, AFS_CELL_REMOVED);743 }744 up_write(&net->cells_lock);745 if (cell->state == AFS_CELL_REMOVED) {746 wake_up_var(&cell->state);747 goto final_destruction;748 }749 if (cell->state == AFS_CELL_FAILED)750 goto done;751 smp_store_release(&cell->state, AFS_CELL_UNSET);752 wake_up_var(&cell->state);753 goto again;754 755 case AFS_CELL_UNSET:756 smp_store_release(&cell->state, AFS_CELL_ACTIVATING);757 wake_up_var(&cell->state);758 goto again;759 760 case AFS_CELL_ACTIVATING:761 ret = afs_activate_cell(net, cell);762 if (ret < 0)763 goto activation_failed;764 765 smp_store_release(&cell->state, AFS_CELL_ACTIVE);766 wake_up_var(&cell->state);767 goto again;768 769 case AFS_CELL_ACTIVE:770 if (atomic_read(&cell->active) > 1) {771 if (test_and_clear_bit(AFS_CELL_FL_DO_LOOKUP, &cell->flags)) {772 ret = afs_update_cell(cell);773 if (ret < 0)774 cell->error = ret;775 }776 goto done;777 }778 smp_store_release(&cell->state, AFS_CELL_DEACTIVATING);779 wake_up_var(&cell->state);780 goto again;781 782 case AFS_CELL_DEACTIVATING:783 if (atomic_read(&cell->active) > 1)784 goto reverse_deactivation;785 afs_deactivate_cell(net, cell);786 smp_store_release(&cell->state, AFS_CELL_INACTIVE);787 wake_up_var(&cell->state);788 goto again;789 790 case AFS_CELL_REMOVED:791 goto done;792 793 default:794 break;795 }796 _debug("bad state %u", cell->state);797 BUG(); /* Unhandled state */798 799activation_failed:800 cell->error = ret;801 afs_deactivate_cell(net, cell);802 803 smp_store_release(&cell->state, AFS_CELL_FAILED); /* vs error */804 wake_up_var(&cell->state);805 goto again;806 807reverse_deactivation:808 smp_store_release(&cell->state, AFS_CELL_ACTIVE);809 wake_up_var(&cell->state);810 _leave(" [deact->act]");811 return;812 813done:814 _leave(" [done %u]", cell->state);815 return;816 817final_destruction:818 /* The root volume is pinning the cell */819 afs_put_volume(cell->root_volume, afs_volume_trace_put_cell_root);820 cell->root_volume = NULL;821 afs_put_cell(cell, afs_cell_trace_put_destroy);822}823 824static void afs_manage_cell_work(struct work_struct *work)825{826 struct afs_cell *cell = container_of(work, struct afs_cell, manager);827 828 afs_manage_cell(cell);829 afs_put_cell(cell, afs_cell_trace_put_queue_work);830}831 832/*833 * Manage the records of cells known to a network namespace. This includes834 * updating the DNS records and garbage collecting unused cells that were835 * automatically added.836 *837 * Note that constructed cell records may only be removed from net->cells by838 * this work item, so it is safe for this work item to stash a cursor pointing839 * into the tree and then return to caller (provided it skips cells that are840 * still under construction).841 *842 * Note also that we were given an increment on net->cells_outstanding by843 * whoever queued us that we need to deal with before returning.844 */845void afs_manage_cells(struct work_struct *work)846{847 struct afs_net *net = container_of(work, struct afs_net, cells_manager);848 struct rb_node *cursor;849 time64_t now = ktime_get_real_seconds(), next_manage = TIME64_MAX;850 bool purging = !net->live;851 852 _enter("");853 854 /* Trawl the cell database looking for cells that have expired from855 * lack of use and cells whose DNS results have expired and dispatch856 * their managers.857 */858 down_read(&net->cells_lock);859 860 for (cursor = rb_first(&net->cells); cursor; cursor = rb_next(cursor)) {861 struct afs_cell *cell =862 rb_entry(cursor, struct afs_cell, net_node);863 unsigned active;864 bool sched_cell = false;865 866 active = atomic_read(&cell->active);867 trace_afs_cell(cell->debug_id, refcount_read(&cell->ref),868 active, afs_cell_trace_manage);869 870 ASSERTCMP(active, >=, 1);871 872 if (purging) {873 if (test_and_clear_bit(AFS_CELL_FL_NO_GC, &cell->flags)) {874 active = atomic_dec_return(&cell->active);875 trace_afs_cell(cell->debug_id, refcount_read(&cell->ref),876 active, afs_cell_trace_unuse_pin);877 }878 }879 880 if (active == 1) {881 struct afs_vlserver_list *vllist;882 time64_t expire_at = cell->last_inactive;883 884 read_lock(&cell->vl_servers_lock);885 vllist = rcu_dereference_protected(886 cell->vl_servers,887 lockdep_is_held(&cell->vl_servers_lock));888 if (vllist->nr_servers > 0)889 expire_at += afs_cell_gc_delay;890 read_unlock(&cell->vl_servers_lock);891 if (purging || expire_at <= now)892 sched_cell = true;893 else if (expire_at < next_manage)894 next_manage = expire_at;895 }896 897 if (!purging) {898 if (test_bit(AFS_CELL_FL_DO_LOOKUP, &cell->flags))899 sched_cell = true;900 }901 902 if (sched_cell)903 afs_queue_cell(cell, afs_cell_trace_get_queue_manage);904 }905 906 up_read(&net->cells_lock);907 908 /* Update the timer on the way out. We have to pass an increment on909 * cells_outstanding in the namespace that we are in to the timer or910 * the work scheduler.911 */912 if (!purging && next_manage < TIME64_MAX) {913 now = ktime_get_real_seconds();914 915 if (next_manage - now <= 0) {916 if (queue_work(afs_wq, &net->cells_manager))917 atomic_inc(&net->cells_outstanding);918 } else {919 afs_set_cell_timer(net, next_manage - now);920 }921 }922 923 afs_dec_cells_outstanding(net);924 _leave(" [%d]", atomic_read(&net->cells_outstanding));925}926 927/*928 * Purge in-memory cell database.929 */930void afs_cell_purge(struct afs_net *net)931{932 struct afs_cell *ws;933 934 _enter("");935 936 down_write(&net->cells_lock);937 ws = net->ws_cell;938 net->ws_cell = NULL;939 up_write(&net->cells_lock);940 afs_unuse_cell(net, ws, afs_cell_trace_unuse_ws);941 942 _debug("del timer");943 if (del_timer_sync(&net->cells_timer))944 atomic_dec(&net->cells_outstanding);945 946 _debug("kick mgr");947 afs_queue_cell_manager(net);948 949 _debug("wait");950 wait_var_event(&net->cells_outstanding,951 !atomic_read(&net->cells_outstanding));952 _leave("");953}954