| // SPDX-License-Identifier: GPL-2.0-or-later |
| /* AFS cell and server record management |
| * |
| * Copyright (C) 2002, 2017 Red Hat, Inc. All Rights Reserved. |
| * Written by David Howells (dhowells@redhat.com) |
| */ |
| |
| #include <linux/slab.h> |
| #include <linux/key.h> |
| #include <linux/ctype.h> |
| #include <linux/dns_resolver.h> |
| #include <linux/sched.h> |
| #include <linux/inet.h> |
| #include <linux/namei.h> |
| #include <keys/rxrpc-type.h> |
| #include "internal.h" |
| |
| static unsigned __read_mostly afs_cell_gc_delay = 10; |
| static unsigned __read_mostly afs_cell_min_ttl = 10 * 60; |
| static unsigned __read_mostly afs_cell_max_ttl = 24 * 60 * 60; |
| |
| static void afs_manage_cell(struct work_struct *); |
| |
| static void afs_dec_cells_outstanding(struct afs_net *net) |
| { |
| if (atomic_dec_and_test(&net->cells_outstanding)) |
| wake_up_var(&net->cells_outstanding); |
| } |
| |
| /* |
| * Set the cell timer to fire after a given delay, assuming it's not already |
| * set for an earlier time. |
| */ |
| static void afs_set_cell_timer(struct afs_net *net, time64_t delay) |
| { |
| if (net->live) { |
| atomic_inc(&net->cells_outstanding); |
| if (timer_reduce(&net->cells_timer, jiffies + delay * HZ)) |
| afs_dec_cells_outstanding(net); |
| } |
| } |
| |
| /* |
| * Look up and get an activation reference on a cell record under RCU |
| * conditions. The caller must hold the RCU read lock. |
| */ |
| struct afs_cell *afs_lookup_cell_rcu(struct afs_net *net, |
| const char *name, unsigned int namesz) |
| { |
| struct afs_cell *cell = NULL; |
| struct rb_node *p; |
| int n, seq = 0, ret = 0; |
| |
| _enter("%*.*s", namesz, namesz, name); |
| |
| if (name && namesz == 0) |
| return ERR_PTR(-EINVAL); |
| if (namesz > AFS_MAXCELLNAME) |
| return ERR_PTR(-ENAMETOOLONG); |
| |
| do { |
| /* Unfortunately, rbtree walking doesn't give reliable results |
| * under just the RCU read lock, so we have to check for |
| * changes. |
| */ |
| if (cell) |
| afs_put_cell(net, cell); |
| cell = NULL; |
| ret = -ENOENT; |
| |
| read_seqbegin_or_lock(&net->cells_lock, &seq); |
| |
| if (!name) { |
| cell = rcu_dereference_raw(net->ws_cell); |
| if (cell) { |
| afs_get_cell(cell); |
| ret = 0; |
| break; |
| } |
| ret = -EDESTADDRREQ; |
| continue; |
| } |
| |
| p = rcu_dereference_raw(net->cells.rb_node); |
| while (p) { |
| cell = rb_entry(p, struct afs_cell, net_node); |
| |
| n = strncasecmp(cell->name, name, |
| min_t(size_t, cell->name_len, namesz)); |
| if (n == 0) |
| n = cell->name_len - namesz; |
| if (n < 0) { |
| p = rcu_dereference_raw(p->rb_left); |
| } else if (n > 0) { |
| p = rcu_dereference_raw(p->rb_right); |
| } else { |
| if (atomic_inc_not_zero(&cell->usage)) { |
| ret = 0; |
| break; |
| } |
| /* We want to repeat the search, this time with |
| * the lock properly locked. |
| */ |
| } |
| cell = NULL; |
| } |
| |
| } while (need_seqretry(&net->cells_lock, seq)); |
| |
| done_seqretry(&net->cells_lock, seq); |
| |
| if (ret != 0 && cell) |
| afs_put_cell(net, cell); |
| |
| return ret == 0 ? cell : ERR_PTR(ret); |
| } |
| |
| /* |
| * Set up a cell record and fill in its name, VL server address list and |
| * allocate an anonymous key |
| */ |
| static struct afs_cell *afs_alloc_cell(struct afs_net *net, |
| const char *name, unsigned int namelen, |
| const char *addresses) |
| { |
| struct afs_vlserver_list *vllist; |
| struct afs_cell *cell; |
| int i, ret; |
| |
| ASSERT(name); |
| if (namelen == 0) |
| return ERR_PTR(-EINVAL); |
| if (namelen > AFS_MAXCELLNAME) { |
| _leave(" = -ENAMETOOLONG"); |
| return ERR_PTR(-ENAMETOOLONG); |
| } |
| |
| /* Prohibit cell names that contain unprintable chars, '/' and '@' or |
| * that begin with a dot. This also precludes "@cell". |
| */ |
| if (name[0] == '.') |
| return ERR_PTR(-EINVAL); |
| for (i = 0; i < namelen; i++) { |
| char ch = name[i]; |
| if (!isprint(ch) || ch == '/' || ch == '@') |
| return ERR_PTR(-EINVAL); |
| } |
| |
| _enter("%*.*s,%s", namelen, namelen, name, addresses); |
| |
| cell = kzalloc(sizeof(struct afs_cell), GFP_KERNEL); |
| if (!cell) { |
| _leave(" = -ENOMEM"); |
| return ERR_PTR(-ENOMEM); |
| } |
| |
| cell->name = kmalloc(namelen + 1, GFP_KERNEL); |
| if (!cell->name) { |
| kfree(cell); |
| return ERR_PTR(-ENOMEM); |
| } |
| |
| cell->net = net; |
| cell->name_len = namelen; |
| for (i = 0; i < namelen; i++) |
| cell->name[i] = tolower(name[i]); |
| cell->name[i] = 0; |
| |
| atomic_set(&cell->usage, 2); |
| INIT_WORK(&cell->manager, afs_manage_cell); |
| INIT_LIST_HEAD(&cell->proc_volumes); |
| rwlock_init(&cell->proc_lock); |
| rwlock_init(&cell->vl_servers_lock); |
| |
| /* Provide a VL server list, filling it in if we were given a list of |
| * addresses to use. |
| */ |
| if (addresses) { |
| vllist = afs_parse_text_addrs(net, |
| addresses, strlen(addresses), ':', |
| VL_SERVICE, AFS_VL_PORT); |
| if (IS_ERR(vllist)) { |
| ret = PTR_ERR(vllist); |
| goto parse_failed; |
| } |
| |
| vllist->source = DNS_RECORD_FROM_CONFIG; |
| vllist->status = DNS_LOOKUP_NOT_DONE; |
| cell->dns_expiry = TIME64_MAX; |
| } else { |
| ret = -ENOMEM; |
| vllist = afs_alloc_vlserver_list(0); |
| if (!vllist) |
| goto error; |
| vllist->source = DNS_RECORD_UNAVAILABLE; |
| vllist->status = DNS_LOOKUP_NOT_DONE; |
| cell->dns_expiry = ktime_get_real_seconds(); |
| } |
| |
| rcu_assign_pointer(cell->vl_servers, vllist); |
| |
| cell->dns_source = vllist->source; |
| cell->dns_status = vllist->status; |
| smp_store_release(&cell->dns_lookup_count, 1); /* vs source/status */ |
| |
| _leave(" = %p", cell); |
| return cell; |
| |
| parse_failed: |
| if (ret == -EINVAL) |
| printk(KERN_ERR "kAFS: bad VL server IP address\n"); |
| error: |
| kfree(cell->name); |
| kfree(cell); |
| _leave(" = %d", ret); |
| return ERR_PTR(ret); |
| } |
| |
| /* |
| * afs_lookup_cell - Look up or create a cell record. |
| * @net: The network namespace |
| * @name: The name of the cell. |
| * @namesz: The strlen of the cell name. |
| * @vllist: A colon/comma separated list of numeric IP addresses or NULL. |
| * @excl: T if an error should be given if the cell name already exists. |
| * |
| * Look up a cell record by name and query the DNS for VL server addresses if |
| * needed. Note that that actual DNS query is punted off to the manager thread |
| * so that this function can return immediately if interrupted whilst allowing |
| * cell records to be shared even if not yet fully constructed. |
| */ |
| struct afs_cell *afs_lookup_cell(struct afs_net *net, |
| const char *name, unsigned int namesz, |
| const char *vllist, bool excl) |
| { |
| struct afs_cell *cell, *candidate, *cursor; |
| struct rb_node *parent, **pp; |
| enum afs_cell_state state; |
| int ret, n; |
| |
| _enter("%s,%s", name, vllist); |
| |
| if (!excl) { |
| rcu_read_lock(); |
| cell = afs_lookup_cell_rcu(net, name, namesz); |
| rcu_read_unlock(); |
| if (!IS_ERR(cell)) |
| goto wait_for_cell; |
| } |
| |
| /* Assume we're probably going to create a cell and preallocate and |
| * mostly set up a candidate record. We can then use this to stash the |
| * name, the net namespace and VL server addresses. |
| * |
| * We also want to do this before we hold any locks as it may involve |
| * upcalling to userspace to make DNS queries. |
| */ |
| candidate = afs_alloc_cell(net, name, namesz, vllist); |
| if (IS_ERR(candidate)) { |
| _leave(" = %ld", PTR_ERR(candidate)); |
| return candidate; |
| } |
| |
| /* Find the insertion point and check to see if someone else added a |
| * cell whilst we were allocating. |
| */ |
| write_seqlock(&net->cells_lock); |
| |
| pp = &net->cells.rb_node; |
| parent = NULL; |
| while (*pp) { |
| parent = *pp; |
| cursor = rb_entry(parent, struct afs_cell, net_node); |
| |
| n = strncasecmp(cursor->name, name, |
| min_t(size_t, cursor->name_len, namesz)); |
| if (n == 0) |
| n = cursor->name_len - namesz; |
| if (n < 0) |
| pp = &(*pp)->rb_left; |
| else if (n > 0) |
| pp = &(*pp)->rb_right; |
| else |
| goto cell_already_exists; |
| } |
| |
| cell = candidate; |
| candidate = NULL; |
| rb_link_node_rcu(&cell->net_node, parent, pp); |
| rb_insert_color(&cell->net_node, &net->cells); |
| atomic_inc(&net->cells_outstanding); |
| write_sequnlock(&net->cells_lock); |
| |
| queue_work(afs_wq, &cell->manager); |
| |
| wait_for_cell: |
| _debug("wait_for_cell"); |
| wait_var_event(&cell->state, |
| ({ |
| state = smp_load_acquire(&cell->state); /* vs error */ |
| state == AFS_CELL_ACTIVE || state == AFS_CELL_FAILED; |
| })); |
| |
| /* Check the state obtained from the wait check. */ |
| if (state == AFS_CELL_FAILED) { |
| ret = cell->error; |
| goto error; |
| } |
| |
| _leave(" = %p [cell]", cell); |
| return cell; |
| |
| cell_already_exists: |
| _debug("cell exists"); |
| cell = cursor; |
| if (excl) { |
| ret = -EEXIST; |
| } else { |
| afs_get_cell(cursor); |
| ret = 0; |
| } |
| write_sequnlock(&net->cells_lock); |
| kfree(candidate); |
| if (ret == 0) |
| goto wait_for_cell; |
| goto error_noput; |
| error: |
| afs_put_cell(net, cell); |
| error_noput: |
| _leave(" = %d [error]", ret); |
| return ERR_PTR(ret); |
| } |
| |
| /* |
| * set the root cell information |
| * - can be called with a module parameter string |
| * - can be called from a write to /proc/fs/afs/rootcell |
| */ |
| int afs_cell_init(struct afs_net *net, const char *rootcell) |
| { |
| struct afs_cell *old_root, *new_root; |
| const char *cp, *vllist; |
| size_t len; |
| |
| _enter(""); |
| |
| if (!rootcell) { |
| /* module is loaded with no parameters, or built statically. |
| * - in the future we might initialize cell DB here. |
| */ |
| _leave(" = 0 [no root]"); |
| return 0; |
| } |
| |
| cp = strchr(rootcell, ':'); |
| if (!cp) { |
| _debug("kAFS: no VL server IP addresses specified"); |
| vllist = NULL; |
| len = strlen(rootcell); |
| } else { |
| vllist = cp + 1; |
| len = cp - rootcell; |
| } |
| |
| /* allocate a cell record for the root cell */ |
| new_root = afs_lookup_cell(net, rootcell, len, vllist, false); |
| if (IS_ERR(new_root)) { |
| _leave(" = %ld", PTR_ERR(new_root)); |
| return PTR_ERR(new_root); |
| } |
| |
| if (!test_and_set_bit(AFS_CELL_FL_NO_GC, &new_root->flags)) |
| afs_get_cell(new_root); |
| |
| /* install the new cell */ |
| write_seqlock(&net->cells_lock); |
| old_root = rcu_access_pointer(net->ws_cell); |
| rcu_assign_pointer(net->ws_cell, new_root); |
| write_sequnlock(&net->cells_lock); |
| |
| afs_put_cell(net, old_root); |
| _leave(" = 0"); |
| return 0; |
| } |
| |
| /* |
| * Update a cell's VL server address list from the DNS. |
| */ |
| static int afs_update_cell(struct afs_cell *cell) |
| { |
| struct afs_vlserver_list *vllist, *old = NULL, *p; |
| unsigned int min_ttl = READ_ONCE(afs_cell_min_ttl); |
| unsigned int max_ttl = READ_ONCE(afs_cell_max_ttl); |
| time64_t now, expiry = 0; |
| int ret = 0; |
| |
| _enter("%s", cell->name); |
| |
| vllist = afs_dns_query(cell, &expiry); |
| if (IS_ERR(vllist)) { |
| ret = PTR_ERR(vllist); |
| |
| _debug("%s: fail %d", cell->name, ret); |
| if (ret == -ENOMEM) |
| goto out_wake; |
| |
| vllist = afs_alloc_vlserver_list(0); |
| if (!vllist) { |
| if (ret >= 0) |
| ret = -ENOMEM; |
| goto out_wake; |
| } |
| |
| switch (ret) { |
| case -ENODATA: |
| case -EDESTADDRREQ: |
| vllist->status = DNS_LOOKUP_GOT_NOT_FOUND; |
| break; |
| case -EAGAIN: |
| case -ECONNREFUSED: |
| vllist->status = DNS_LOOKUP_GOT_TEMP_FAILURE; |
| break; |
| default: |
| vllist->status = DNS_LOOKUP_GOT_LOCAL_FAILURE; |
| break; |
| } |
| } |
| |
| _debug("%s: got list %d %d", cell->name, vllist->source, vllist->status); |
| cell->dns_status = vllist->status; |
| |
| now = ktime_get_real_seconds(); |
| if (min_ttl > max_ttl) |
| max_ttl = min_ttl; |
| if (expiry < now + min_ttl) |
| expiry = now + min_ttl; |
| else if (expiry > now + max_ttl) |
| expiry = now + max_ttl; |
| |
| _debug("%s: status %d", cell->name, vllist->status); |
| if (vllist->source == DNS_RECORD_UNAVAILABLE) { |
| switch (vllist->status) { |
| case DNS_LOOKUP_GOT_NOT_FOUND: |
| /* The DNS said that the cell does not exist or there |
| * weren't any addresses to be had. |
| */ |
| cell->dns_expiry = expiry; |
| break; |
| |
| case DNS_LOOKUP_BAD: |
| case DNS_LOOKUP_GOT_LOCAL_FAILURE: |
| case DNS_LOOKUP_GOT_TEMP_FAILURE: |
| case DNS_LOOKUP_GOT_NS_FAILURE: |
| default: |
| cell->dns_expiry = now + 10; |
| break; |
| } |
| } else { |
| cell->dns_expiry = expiry; |
| } |
| |
| /* Replace the VL server list if the new record has servers or the old |
| * record doesn't. |
| */ |
| write_lock(&cell->vl_servers_lock); |
| p = rcu_dereference_protected(cell->vl_servers, true); |
| if (vllist->nr_servers > 0 || p->nr_servers == 0) { |
| rcu_assign_pointer(cell->vl_servers, vllist); |
| cell->dns_source = vllist->source; |
| old = p; |
| } |
| write_unlock(&cell->vl_servers_lock); |
| afs_put_vlserverlist(cell->net, old); |
| |
| out_wake: |
| smp_store_release(&cell->dns_lookup_count, |
| cell->dns_lookup_count + 1); /* vs source/status */ |
| wake_up_var(&cell->dns_lookup_count); |
| _leave(" = %d", ret); |
| return ret; |
| } |
| |
| /* |
| * Destroy a cell record |
| */ |
| static void afs_cell_destroy(struct rcu_head *rcu) |
| { |
| struct afs_cell *cell = container_of(rcu, struct afs_cell, rcu); |
| |
| _enter("%p{%s}", cell, cell->name); |
| |
| ASSERTCMP(atomic_read(&cell->usage), ==, 0); |
| |
| afs_put_vlserverlist(cell->net, rcu_access_pointer(cell->vl_servers)); |
| key_put(cell->anonymous_key); |
| kfree(cell->name); |
| kfree(cell); |
| |
| _leave(" [destroyed]"); |
| } |
| |
| /* |
| * Queue the cell manager. |
| */ |
| static void afs_queue_cell_manager(struct afs_net *net) |
| { |
| int outstanding = atomic_inc_return(&net->cells_outstanding); |
| |
| _enter("%d", outstanding); |
| |
| if (!queue_work(afs_wq, &net->cells_manager)) |
| afs_dec_cells_outstanding(net); |
| } |
| |
| /* |
| * Cell management timer. We have an increment on cells_outstanding that we |
| * need to pass along to the work item. |
| */ |
| void afs_cells_timer(struct timer_list *timer) |
| { |
| struct afs_net *net = container_of(timer, struct afs_net, cells_timer); |
| |
| _enter(""); |
| if (!queue_work(afs_wq, &net->cells_manager)) |
| afs_dec_cells_outstanding(net); |
| } |
| |
| /* |
| * Get a reference on a cell record. |
| */ |
| struct afs_cell *afs_get_cell(struct afs_cell *cell) |
| { |
| atomic_inc(&cell->usage); |
| return cell; |
| } |
| |
| /* |
| * Drop a reference on a cell record. |
| */ |
| void afs_put_cell(struct afs_net *net, struct afs_cell *cell) |
| { |
| time64_t now, expire_delay; |
| |
| if (!cell) |
| return; |
| |
| _enter("%s", cell->name); |
| |
| now = ktime_get_real_seconds(); |
| cell->last_inactive = now; |
| expire_delay = 0; |
| if (cell->vl_servers->nr_servers) |
| expire_delay = afs_cell_gc_delay; |
| |
| if (atomic_dec_return(&cell->usage) > 1) |
| return; |
| |
| /* 'cell' may now be garbage collected. */ |
| afs_set_cell_timer(net, expire_delay); |
| } |
| |
| /* |
| * Allocate a key to use as a placeholder for anonymous user security. |
| */ |
| static int afs_alloc_anon_key(struct afs_cell *cell) |
| { |
| struct key *key; |
| char keyname[4 + AFS_MAXCELLNAME + 1], *cp, *dp; |
| |
| /* Create a key to represent an anonymous user. */ |
| memcpy(keyname, "afs@", 4); |
| dp = keyname + 4; |
| cp = cell->name; |
| do { |
| *dp++ = tolower(*cp); |
| } while (*cp++); |
| |
| key = rxrpc_get_null_key(keyname); |
| if (IS_ERR(key)) |
| return PTR_ERR(key); |
| |
| cell->anonymous_key = key; |
| |
| _debug("anon key %p{%x}", |
| cell->anonymous_key, key_serial(cell->anonymous_key)); |
| return 0; |
| } |
| |
| /* |
| * Activate a cell. |
| */ |
| static int afs_activate_cell(struct afs_net *net, struct afs_cell *cell) |
| { |
| struct hlist_node **p; |
| struct afs_cell *pcell; |
| int ret; |
| |
| if (!cell->anonymous_key) { |
| ret = afs_alloc_anon_key(cell); |
| if (ret < 0) |
| return ret; |
| } |
| |
| #ifdef CONFIG_AFS_FSCACHE |
| cell->cache = fscache_acquire_cookie(afs_cache_netfs.primary_index, |
| &afs_cell_cache_index_def, |
| cell->name, strlen(cell->name), |
| NULL, 0, |
| cell, 0, true); |
| #endif |
| ret = afs_proc_cell_setup(cell); |
| if (ret < 0) |
| return ret; |
| |
| mutex_lock(&net->proc_cells_lock); |
| for (p = &net->proc_cells.first; *p; p = &(*p)->next) { |
| pcell = hlist_entry(*p, struct afs_cell, proc_link); |
| if (strcmp(cell->name, pcell->name) < 0) |
| break; |
| } |
| |
| cell->proc_link.pprev = p; |
| cell->proc_link.next = *p; |
| rcu_assign_pointer(*p, &cell->proc_link.next); |
| if (cell->proc_link.next) |
| cell->proc_link.next->pprev = &cell->proc_link.next; |
| |
| afs_dynroot_mkdir(net, cell); |
| mutex_unlock(&net->proc_cells_lock); |
| return 0; |
| } |
| |
| /* |
| * Deactivate a cell. |
| */ |
| static void afs_deactivate_cell(struct afs_net *net, struct afs_cell *cell) |
| { |
| _enter("%s", cell->name); |
| |
| afs_proc_cell_remove(cell); |
| |
| mutex_lock(&net->proc_cells_lock); |
| hlist_del_rcu(&cell->proc_link); |
| afs_dynroot_rmdir(net, cell); |
| mutex_unlock(&net->proc_cells_lock); |
| |
| #ifdef CONFIG_AFS_FSCACHE |
| fscache_relinquish_cookie(cell->cache, NULL, false); |
| cell->cache = NULL; |
| #endif |
| |
| _leave(""); |
| } |
| |
| /* |
| * Manage a cell record, initialising and destroying it, maintaining its DNS |
| * records. |
| */ |
| static void afs_manage_cell(struct work_struct *work) |
| { |
| struct afs_cell *cell = container_of(work, struct afs_cell, manager); |
| struct afs_net *net = cell->net; |
| bool deleted; |
| int ret, usage; |
| |
| _enter("%s", cell->name); |
| |
| again: |
| _debug("state %u", cell->state); |
| switch (cell->state) { |
| case AFS_CELL_INACTIVE: |
| case AFS_CELL_FAILED: |
| write_seqlock(&net->cells_lock); |
| usage = 1; |
| deleted = atomic_try_cmpxchg_relaxed(&cell->usage, &usage, 0); |
| if (deleted) |
| rb_erase(&cell->net_node, &net->cells); |
| write_sequnlock(&net->cells_lock); |
| if (deleted) |
| goto final_destruction; |
| if (cell->state == AFS_CELL_FAILED) |
| goto done; |
| smp_store_release(&cell->state, AFS_CELL_UNSET); |
| wake_up_var(&cell->state); |
| goto again; |
| |
| case AFS_CELL_UNSET: |
| smp_store_release(&cell->state, AFS_CELL_ACTIVATING); |
| wake_up_var(&cell->state); |
| goto again; |
| |
| case AFS_CELL_ACTIVATING: |
| ret = afs_activate_cell(net, cell); |
| if (ret < 0) |
| goto activation_failed; |
| |
| smp_store_release(&cell->state, AFS_CELL_ACTIVE); |
| wake_up_var(&cell->state); |
| goto again; |
| |
| case AFS_CELL_ACTIVE: |
| if (atomic_read(&cell->usage) > 1) { |
| if (test_and_clear_bit(AFS_CELL_FL_DO_LOOKUP, &cell->flags)) { |
| ret = afs_update_cell(cell); |
| if (ret < 0) |
| cell->error = ret; |
| } |
| goto done; |
| } |
| smp_store_release(&cell->state, AFS_CELL_DEACTIVATING); |
| wake_up_var(&cell->state); |
| goto again; |
| |
| case AFS_CELL_DEACTIVATING: |
| if (atomic_read(&cell->usage) > 1) |
| goto reverse_deactivation; |
| afs_deactivate_cell(net, cell); |
| smp_store_release(&cell->state, AFS_CELL_INACTIVE); |
| wake_up_var(&cell->state); |
| goto again; |
| |
| default: |
| break; |
| } |
| _debug("bad state %u", cell->state); |
| BUG(); /* Unhandled state */ |
| |
| activation_failed: |
| cell->error = ret; |
| afs_deactivate_cell(net, cell); |
| |
| smp_store_release(&cell->state, AFS_CELL_FAILED); /* vs error */ |
| wake_up_var(&cell->state); |
| goto again; |
| |
| reverse_deactivation: |
| smp_store_release(&cell->state, AFS_CELL_ACTIVE); |
| wake_up_var(&cell->state); |
| _leave(" [deact->act]"); |
| return; |
| |
| done: |
| _leave(" [done %u]", cell->state); |
| return; |
| |
| final_destruction: |
| call_rcu(&cell->rcu, afs_cell_destroy); |
| afs_dec_cells_outstanding(net); |
| _leave(" [destruct %d]", atomic_read(&net->cells_outstanding)); |
| } |
| |
| /* |
| * Manage the records of cells known to a network namespace. This includes |
| * updating the DNS records and garbage collecting unused cells that were |
| * automatically added. |
| * |
| * Note that constructed cell records may only be removed from net->cells by |
| * this work item, so it is safe for this work item to stash a cursor pointing |
| * into the tree and then return to caller (provided it skips cells that are |
| * still under construction). |
| * |
| * Note also that we were given an increment on net->cells_outstanding by |
| * whoever queued us that we need to deal with before returning. |
| */ |
| void afs_manage_cells(struct work_struct *work) |
| { |
| struct afs_net *net = container_of(work, struct afs_net, cells_manager); |
| struct rb_node *cursor; |
| time64_t now = ktime_get_real_seconds(), next_manage = TIME64_MAX; |
| bool purging = !net->live; |
| |
| _enter(""); |
| |
| /* Trawl the cell database looking for cells that have expired from |
| * lack of use and cells whose DNS results have expired and dispatch |
| * their managers. |
| */ |
| read_seqlock_excl(&net->cells_lock); |
| |
| for (cursor = rb_first(&net->cells); cursor; cursor = rb_next(cursor)) { |
| struct afs_cell *cell = |
| rb_entry(cursor, struct afs_cell, net_node); |
| unsigned usage; |
| bool sched_cell = false; |
| |
| usage = atomic_read(&cell->usage); |
| _debug("manage %s %u", cell->name, usage); |
| |
| ASSERTCMP(usage, >=, 1); |
| |
| if (purging) { |
| if (test_and_clear_bit(AFS_CELL_FL_NO_GC, &cell->flags)) |
| usage = atomic_dec_return(&cell->usage); |
| ASSERTCMP(usage, ==, 1); |
| } |
| |
| if (usage == 1) { |
| struct afs_vlserver_list *vllist; |
| time64_t expire_at = cell->last_inactive; |
| |
| read_lock(&cell->vl_servers_lock); |
| vllist = rcu_dereference_protected( |
| cell->vl_servers, |
| lockdep_is_held(&cell->vl_servers_lock)); |
| if (vllist->nr_servers > 0) |
| expire_at += afs_cell_gc_delay; |
| read_unlock(&cell->vl_servers_lock); |
| if (purging || expire_at <= now) |
| sched_cell = true; |
| else if (expire_at < next_manage) |
| next_manage = expire_at; |
| } |
| |
| if (!purging) { |
| if (test_bit(AFS_CELL_FL_DO_LOOKUP, &cell->flags)) |
| sched_cell = true; |
| } |
| |
| if (sched_cell) |
| queue_work(afs_wq, &cell->manager); |
| } |
| |
| read_sequnlock_excl(&net->cells_lock); |
| |
| /* Update the timer on the way out. We have to pass an increment on |
| * cells_outstanding in the namespace that we are in to the timer or |
| * the work scheduler. |
| */ |
| if (!purging && next_manage < TIME64_MAX) { |
| now = ktime_get_real_seconds(); |
| |
| if (next_manage - now <= 0) { |
| if (queue_work(afs_wq, &net->cells_manager)) |
| atomic_inc(&net->cells_outstanding); |
| } else { |
| afs_set_cell_timer(net, next_manage - now); |
| } |
| } |
| |
| afs_dec_cells_outstanding(net); |
| _leave(" [%d]", atomic_read(&net->cells_outstanding)); |
| } |
| |
| /* |
| * Purge in-memory cell database. |
| */ |
| void afs_cell_purge(struct afs_net *net) |
| { |
| struct afs_cell *ws; |
| |
| _enter(""); |
| |
| write_seqlock(&net->cells_lock); |
| ws = rcu_access_pointer(net->ws_cell); |
| RCU_INIT_POINTER(net->ws_cell, NULL); |
| write_sequnlock(&net->cells_lock); |
| afs_put_cell(net, ws); |
| |
| _debug("del timer"); |
| if (del_timer_sync(&net->cells_timer)) |
| atomic_dec(&net->cells_outstanding); |
| |
| _debug("kick mgr"); |
| afs_queue_cell_manager(net); |
| |
| _debug("wait"); |
| wait_var_event(&net->cells_outstanding, |
| !atomic_read(&net->cells_outstanding)); |
| _leave(""); |
| } |