summaryrefslogtreecommitdiffstats
path: root/fs/afs/cell.c
diff options
context:
space:
mode:
authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
commit2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch)
tree848558de17fb3008cdf4d861b01ac7781903ce39 /fs/afs/cell.c
parentInitial commit. (diff)
downloadlinux-2c3c1048746a4622d8c89a29670120dc8fab93c4.tar.xz
linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.zip
Adding upstream version 6.1.76.upstream/6.1.76
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'fs/afs/cell.c')
-rw-r--r--fs/afs/cell.c954
1 files changed, 954 insertions, 0 deletions
diff --git a/fs/afs/cell.c b/fs/afs/cell.c
new file mode 100644
index 000000000..926cb1188
--- /dev/null
+++ b/fs/afs/cell.c
@@ -0,0 +1,954 @@
+// 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 atomic_t cell_debug_id;
+
+static void afs_queue_cell_manager(struct afs_net *);
+static void afs_manage_cell_work(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);
+ } else {
+ afs_queue_cell_manager(net);
+ }
+}
+
+/*
+ * Look up and get an activation reference on a cell record. The caller must
+ * hold net->cells_lock at least read-locked.
+ */
+static struct afs_cell *afs_find_cell_locked(struct afs_net *net,
+ const char *name, unsigned int namesz,
+ enum afs_cell_trace reason)
+{
+ struct afs_cell *cell = NULL;
+ struct rb_node *p;
+ int n;
+
+ _enter("%*.*s", namesz, namesz, name);
+
+ if (name && namesz == 0)
+ return ERR_PTR(-EINVAL);
+ if (namesz > AFS_MAXCELLNAME)
+ return ERR_PTR(-ENAMETOOLONG);
+
+ if (!name) {
+ cell = net->ws_cell;
+ if (!cell)
+ return ERR_PTR(-EDESTADDRREQ);
+ goto found;
+ }
+
+ p = 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 = p->rb_left;
+ else if (n > 0)
+ p = p->rb_right;
+ else
+ goto found;
+ }
+
+ return ERR_PTR(-ENOENT);
+
+found:
+ return afs_use_cell(cell, reason);
+}
+
+/*
+ * Look up and get an activation reference on a cell record.
+ */
+struct afs_cell *afs_find_cell(struct afs_net *net,
+ const char *name, unsigned int namesz,
+ enum afs_cell_trace reason)
+{
+ struct afs_cell *cell;
+
+ down_read(&net->cells_lock);
+ cell = afs_find_cell_locked(net, name, namesz, reason);
+ up_read(&net->cells_lock);
+ return cell;
+}
+
+/*
+ * 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;
+
+ refcount_set(&cell->ref, 1);
+ atomic_set(&cell->active, 0);
+ INIT_WORK(&cell->manager, afs_manage_cell_work);
+ cell->volumes = RB_ROOT;
+ INIT_HLIST_HEAD(&cell->proc_volumes);
+ seqlock_init(&cell->volume_lock);
+ cell->fs_servers = RB_ROOT;
+ seqlock_init(&cell->fs_lock);
+ INIT_LIST_HEAD(&cell->fs_open_mmaps);
+ init_rwsem(&cell->fs_open_mmaps_lock);
+ rwlock_init(&cell->vl_servers_lock);
+ cell->flags = (1 << AFS_CELL_FL_CHECK_ALIAS);
+
+ /* 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 */
+ atomic_inc(&net->cells_outstanding);
+ cell->debug_id = atomic_inc_return(&cell_debug_id);
+ trace_afs_cell(cell->debug_id, 1, 0, afs_cell_trace_alloc);
+
+ _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) {
+ cell = afs_find_cell(net, name, namesz, afs_cell_trace_use_lookup);
+ 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.
+ */
+ down_write(&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;
+ atomic_set(&cell->active, 2);
+ trace_afs_cell(cell->debug_id, refcount_read(&cell->ref), 2, afs_cell_trace_insert);
+ rb_link_node_rcu(&cell->net_node, parent, pp);
+ rb_insert_color(&cell->net_node, &net->cells);
+ up_write(&net->cells_lock);
+
+ afs_queue_cell(cell, afs_cell_trace_get_queue_new);
+
+wait_for_cell:
+ trace_afs_cell(cell->debug_id, refcount_read(&cell->ref), atomic_read(&cell->active),
+ afs_cell_trace_wait);
+ _debug("wait_for_cell");
+ wait_var_event(&cell->state,
+ ({
+ state = smp_load_acquire(&cell->state); /* vs error */
+ state == AFS_CELL_ACTIVE || state == AFS_CELL_REMOVED;
+ }));
+
+ /* Check the state obtained from the wait check. */
+ if (state == AFS_CELL_REMOVED) {
+ 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_use_cell(cursor, afs_cell_trace_use_lookup);
+ ret = 0;
+ }
+ up_write(&net->cells_lock);
+ if (candidate)
+ afs_put_cell(candidate, afs_cell_trace_put_candidate);
+ if (ret == 0)
+ goto wait_for_cell;
+ goto error_noput;
+error:
+ afs_unuse_cell(net, cell, afs_cell_trace_unuse_lookup);
+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_use_cell(new_root, afs_cell_trace_use_pin);
+
+ /* install the new cell */
+ down_write(&net->cells_lock);
+ afs_see_cell(new_root, afs_cell_trace_see_ws);
+ old_root = net->ws_cell;
+ net->ws_cell = new_root;
+ up_write(&net->cells_lock);
+
+ afs_unuse_cell(net, old_root, afs_cell_trace_unuse_ws);
+ _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);
+ struct afs_net *net = cell->net;
+ int r;
+
+ _enter("%p{%s}", cell, cell->name);
+
+ r = refcount_read(&cell->ref);
+ ASSERTCMP(r, ==, 0);
+ trace_afs_cell(cell->debug_id, r, atomic_read(&cell->active), afs_cell_trace_free);
+
+ afs_put_vlserverlist(net, rcu_access_pointer(cell->vl_servers));
+ afs_unuse_cell(net, cell->alias_of, afs_cell_trace_unuse_alias);
+ key_put(cell->anonymous_key);
+ kfree(cell->name);
+ kfree(cell);
+
+ afs_dec_cells_outstanding(net);
+ _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, enum afs_cell_trace reason)
+{
+ int r;
+
+ __refcount_inc(&cell->ref, &r);
+ trace_afs_cell(cell->debug_id, r + 1, atomic_read(&cell->active), reason);
+ return cell;
+}
+
+/*
+ * Drop a reference on a cell record.
+ */
+void afs_put_cell(struct afs_cell *cell, enum afs_cell_trace reason)
+{
+ if (cell) {
+ unsigned int debug_id = cell->debug_id;
+ unsigned int a;
+ bool zero;
+ int r;
+
+ a = atomic_read(&cell->active);
+ zero = __refcount_dec_and_test(&cell->ref, &r);
+ trace_afs_cell(debug_id, r - 1, a, reason);
+ if (zero) {
+ a = atomic_read(&cell->active);
+ WARN(a != 0, "Cell active count %u > 0\n", a);
+ call_rcu(&cell->rcu, afs_cell_destroy);
+ }
+ }
+}
+
+/*
+ * Note a cell becoming more active.
+ */
+struct afs_cell *afs_use_cell(struct afs_cell *cell, enum afs_cell_trace reason)
+{
+ int r, a;
+
+ r = refcount_read(&cell->ref);
+ WARN_ON(r == 0);
+ a = atomic_inc_return(&cell->active);
+ trace_afs_cell(cell->debug_id, r, a, reason);
+ return cell;
+}
+
+/*
+ * Record a cell becoming less active. When the active counter reaches 1, it
+ * is scheduled for destruction, but may get reactivated.
+ */
+void afs_unuse_cell(struct afs_net *net, struct afs_cell *cell, enum afs_cell_trace reason)
+{
+ unsigned int debug_id;
+ time64_t now, expire_delay;
+ int r, a;
+
+ 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;
+
+ debug_id = cell->debug_id;
+ r = refcount_read(&cell->ref);
+ a = atomic_dec_return(&cell->active);
+ trace_afs_cell(debug_id, r, a, reason);
+ WARN_ON(a == 0);
+ if (a == 1)
+ /* 'cell' may now be garbage collected. */
+ afs_set_cell_timer(net, expire_delay);
+}
+
+/*
+ * Note that a cell has been seen.
+ */
+void afs_see_cell(struct afs_cell *cell, enum afs_cell_trace reason)
+{
+ int r, a;
+
+ r = refcount_read(&cell->ref);
+ a = atomic_read(&cell->active);
+ trace_afs_cell(cell->debug_id, r, a, reason);
+}
+
+/*
+ * Queue a cell for management, giving the workqueue a ref to hold.
+ */
+void afs_queue_cell(struct afs_cell *cell, enum afs_cell_trace reason)
+{
+ afs_get_cell(cell, reason);
+ if (!queue_work(afs_wq, &cell->manager))
+ afs_put_cell(cell, afs_cell_trace_put_queue_fail);
+}
+
+/*
+ * 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;
+ }
+
+ 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);
+
+ _leave("");
+}
+
+/*
+ * Manage a cell record, initialising and destroying it, maintaining its DNS
+ * records.
+ */
+static void afs_manage_cell(struct afs_cell *cell)
+{
+ struct afs_net *net = cell->net;
+ int ret, active;
+
+ _enter("%s", cell->name);
+
+again:
+ _debug("state %u", cell->state);
+ switch (cell->state) {
+ case AFS_CELL_INACTIVE:
+ case AFS_CELL_FAILED:
+ down_write(&net->cells_lock);
+ active = 1;
+ if (atomic_try_cmpxchg_relaxed(&cell->active, &active, 0)) {
+ rb_erase(&cell->net_node, &net->cells);
+ trace_afs_cell(cell->debug_id, refcount_read(&cell->ref), 0,
+ afs_cell_trace_unuse_delete);
+ smp_store_release(&cell->state, AFS_CELL_REMOVED);
+ }
+ up_write(&net->cells_lock);
+ if (cell->state == AFS_CELL_REMOVED) {
+ wake_up_var(&cell->state);
+ 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->active) > 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->active) > 1)
+ goto reverse_deactivation;
+ afs_deactivate_cell(net, cell);
+ smp_store_release(&cell->state, AFS_CELL_INACTIVE);
+ wake_up_var(&cell->state);
+ goto again;
+
+ case AFS_CELL_REMOVED:
+ goto done;
+
+ 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:
+ /* The root volume is pinning the cell */
+ afs_put_volume(cell->net, cell->root_volume, afs_volume_trace_put_cell_root);
+ cell->root_volume = NULL;
+ afs_put_cell(cell, afs_cell_trace_put_destroy);
+}
+
+static void afs_manage_cell_work(struct work_struct *work)
+{
+ struct afs_cell *cell = container_of(work, struct afs_cell, manager);
+
+ afs_manage_cell(cell);
+ afs_put_cell(cell, afs_cell_trace_put_queue_work);
+}
+
+/*
+ * 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.
+ */
+ down_read(&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 active;
+ bool sched_cell = false;
+
+ active = atomic_read(&cell->active);
+ trace_afs_cell(cell->debug_id, refcount_read(&cell->ref),
+ active, afs_cell_trace_manage);
+
+ ASSERTCMP(active, >=, 1);
+
+ if (purging) {
+ if (test_and_clear_bit(AFS_CELL_FL_NO_GC, &cell->flags)) {
+ active = atomic_dec_return(&cell->active);
+ trace_afs_cell(cell->debug_id, refcount_read(&cell->ref),
+ active, afs_cell_trace_unuse_pin);
+ }
+ }
+
+ if (active == 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)
+ afs_queue_cell(cell, afs_cell_trace_get_queue_manage);
+ }
+
+ up_read(&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("");
+
+ down_write(&net->cells_lock);
+ ws = net->ws_cell;
+ net->ws_cell = NULL;
+ up_write(&net->cells_lock);
+ afs_unuse_cell(net, ws, afs_cell_trace_unuse_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("");
+}