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-rw-r--r--fs/afs/cell.c887
1 files changed, 601 insertions, 286 deletions
diff --git a/fs/afs/cell.c b/fs/afs/cell.c
index ca0a3cf93791..1858c91169e4 100644
--- a/fs/afs/cell.c
+++ b/fs/afs/cell.c
@@ -1,6 +1,6 @@
/* AFS cell and server record management
*
- * Copyright (C) 2002 Red Hat, Inc. All Rights Reserved.
+ * Copyright (C) 2002, 2017 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*
* This program is free software; you can redistribute it and/or
@@ -9,213 +9,296 @@
* 2 of the License, or (at your option) any later version.
*/
-#include <linux/module.h>
#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 <keys/rxrpc-type.h>
#include "internal.h"
-DECLARE_RWSEM(afs_proc_cells_sem);
-LIST_HEAD(afs_proc_cells);
+unsigned __read_mostly afs_cell_gc_delay = 10;
-static LIST_HEAD(afs_cells);
-static DEFINE_RWLOCK(afs_cells_lock);
-static DECLARE_RWSEM(afs_cells_sem); /* add/remove serialisation */
-static DECLARE_WAIT_QUEUE_HEAD(afs_cells_freeable_wq);
-static struct afs_cell *afs_cell_root;
+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_atomic_t(&net->cells_outstanding);
+}
/*
- * allocate a cell record and fill in its name, VL server address list and
- * allocate an anonymous key
+ * Set the cell timer to fire after a given delay, assuming it's not already
+ * set for an earlier time.
*/
-static struct afs_cell *afs_cell_alloc(const char *name, unsigned namelen,
- char *vllist)
+static void afs_set_cell_timer(struct afs_net *net, time64_t delay)
{
- struct afs_cell *cell;
- struct key *key;
- char keyname[4 + AFS_MAXCELLNAME + 1], *cp, *dp, *next;
- char *dvllist = NULL, *_vllist = NULL;
- char delimiter = ':';
- int ret;
+ if (net->live) {
+ atomic_inc(&net->cells_outstanding);
+ if (timer_reduce(&net->cells_timer, jiffies + delay * HZ))
+ afs_dec_cells_outstanding(net);
+ }
+}
- _enter("%*.*s,%s", namelen, namelen, name ?: "", vllist);
+/*
+ * 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;
- BUG_ON(!name); /* TODO: want to look up "this cell" in the cache */
+ _enter("%*.*s", namesz, namesz, name);
- if (namelen > AFS_MAXCELLNAME) {
- _leave(" = -ENAMETOOLONG");
+ if (name && namesz == 0)
+ return ERR_PTR(-EINVAL);
+ if (namesz > AFS_MAXCELLNAME)
return ERR_PTR(-ENAMETOOLONG);
- }
- /* allocate and initialise a cell record */
- cell = kzalloc(sizeof(struct afs_cell) + namelen + 1, GFP_KERNEL);
- if (!cell) {
- _leave(" = -ENOMEM");
- return ERR_PTR(-ENOMEM);
- }
+ 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;
- memcpy(cell->name, name, namelen);
- cell->name[namelen] = 0;
-
- atomic_set(&cell->usage, 1);
- INIT_LIST_HEAD(&cell->link);
- rwlock_init(&cell->servers_lock);
- INIT_LIST_HEAD(&cell->servers);
- init_rwsem(&cell->vl_sem);
- INIT_LIST_HEAD(&cell->vl_list);
- spin_lock_init(&cell->vl_lock);
-
- /* if the ip address is invalid, try dns query */
- if (!vllist || strlen(vllist) < 7) {
- ret = dns_query("afsdb", name, namelen, "ipv4", &dvllist, NULL);
- if (ret < 0) {
- if (ret == -ENODATA || ret == -EAGAIN || ret == -ENOKEY)
- /* translate these errors into something
- * userspace might understand */
- ret = -EDESTADDRREQ;
- _leave(" = %d", ret);
- return ERR_PTR(ret);
+ read_seqbegin_or_lock(&net->cells_lock, &seq);
+
+ if (!name) {
+ cell = rcu_dereference_raw(net->ws_cell);
+ if (cell) {
+ afs_get_cell(cell);
+ continue;
+ }
+ ret = -EDESTADDRREQ;
+ continue;
}
- _vllist = dvllist;
- /* change the delimiter for user-space reply */
- delimiter = ',';
+ 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;
+ }
- } else {
- _vllist = vllist;
- }
+ } while (need_seqretry(&net->cells_lock, seq));
- /* fill in the VL server list from the rest of the string */
- do {
- unsigned a, b, c, d;
+ done_seqretry(&net->cells_lock, seq);
- next = strchr(_vllist, delimiter);
- if (next)
- *next++ = 0;
+ return ret == 0 ? cell : ERR_PTR(ret);
+}
- if (sscanf(_vllist, "%u.%u.%u.%u", &a, &b, &c, &d) != 4)
- goto bad_address;
+/*
+ * 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 *vllist)
+{
+ struct afs_cell *cell;
+ int i, ret;
- if (a > 255 || b > 255 || c > 255 || d > 255)
- goto bad_address;
+ ASSERT(name);
+ if (namelen == 0)
+ return ERR_PTR(-EINVAL);
+ if (namelen > AFS_MAXCELLNAME) {
+ _leave(" = -ENAMETOOLONG");
+ return ERR_PTR(-ENAMETOOLONG);
+ }
- cell->vl_addrs[cell->vl_naddrs++].s_addr =
- htonl((a << 24) | (b << 16) | (c << 8) | d);
+ _enter("%*.*s,%s", namelen, namelen, name, vllist);
- } while (cell->vl_naddrs < AFS_CELL_MAX_ADDRS && (_vllist = next));
+ cell = kzalloc(sizeof(struct afs_cell), GFP_KERNEL);
+ if (!cell) {
+ _leave(" = -ENOMEM");
+ return ERR_PTR(-ENOMEM);
+ }
- /* create a key to represent an anonymous user */
- memcpy(keyname, "afs@", 4);
- dp = keyname + 4;
- cp = cell->name;
- do {
- *dp++ = toupper(*cp);
- } while (*cp++);
+ cell->net = net;
+ cell->name_len = namelen;
+ for (i = 0; i < namelen; i++)
+ cell->name[i] = tolower(name[i]);
+
+ atomic_set(&cell->usage, 2);
+ INIT_WORK(&cell->manager, afs_manage_cell);
+ cell->flags = ((1 << AFS_CELL_FL_NOT_READY) |
+ (1 << AFS_CELL_FL_NO_LOOKUP_YET));
+ INIT_LIST_HEAD(&cell->proc_volumes);
+ rwlock_init(&cell->proc_lock);
+ rwlock_init(&cell->vl_addrs_lock);
+
+ /* Fill in the VL server list if we were given a list of addresses to
+ * use.
+ */
+ if (vllist) {
+ struct afs_addr_list *alist;
+
+ alist = afs_parse_text_addrs(vllist, strlen(vllist), ':',
+ VL_SERVICE, AFS_VL_PORT);
+ if (IS_ERR(alist)) {
+ ret = PTR_ERR(alist);
+ goto parse_failed;
+ }
- key = rxrpc_get_null_key(keyname);
- if (IS_ERR(key)) {
- _debug("no key");
- ret = PTR_ERR(key);
- goto error;
+ rcu_assign_pointer(cell->vl_addrs, alist);
+ cell->dns_expiry = TIME64_MAX;
}
- cell->anonymous_key = key;
-
- _debug("anon key %p{%x}",
- cell->anonymous_key, key_serial(cell->anonymous_key));
_leave(" = %p", cell);
return cell;
-bad_address:
- printk(KERN_ERR "kAFS: bad VL server IP address\n");
- ret = -EINVAL;
-error:
- key_put(cell->anonymous_key);
- kfree(dvllist);
+parse_failed:
+ if (ret == -EINVAL)
+ printk(KERN_ERR "kAFS: bad VL server IP address\n");
kfree(cell);
_leave(" = %d", ret);
return ERR_PTR(ret);
}
/*
- * afs_cell_crate() - create a cell record
- * @name: is the name of the cell.
- * @namsesz: is the strlen of the cell name.
- * @vllist: is a colon separated list of IP addresses in "a.b.c.d" format.
- * @retref: is T to return the cell reference when the cell exists.
+ * 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_cell_create(const char *name, unsigned namesz,
- char *vllist, bool retref)
+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;
- int ret;
-
- _enter("%*.*s,%s", namesz, namesz, name ?: "", vllist);
+ struct afs_cell *cell, *candidate, *cursor;
+ struct rb_node *parent, **pp;
+ 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)) {
+ if (excl) {
+ afs_put_cell(net, cell);
+ return ERR_PTR(-EEXIST);
+ }
+ goto wait_for_cell;
+ }
+ }
- down_write(&afs_cells_sem);
- read_lock(&afs_cells_lock);
- list_for_each_entry(cell, &afs_cells, link) {
- if (strncasecmp(cell->name, name, namesz) == 0)
- goto duplicate_name;
+ /* 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;
}
- read_unlock(&afs_cells_lock);
- cell = afs_cell_alloc(name, namesz, vllist);
- if (IS_ERR(cell)) {
- _leave(" = %ld", PTR_ERR(cell));
- up_write(&afs_cells_sem);
- return cell;
+ /* 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;
}
- /* add a proc directory for this cell */
- ret = afs_proc_cell_setup(cell);
- if (ret < 0)
- goto error;
+ 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);
-#ifdef CONFIG_AFS_FSCACHE
- /* put it up for caching (this never returns an error) */
- cell->cache = fscache_acquire_cookie(afs_cache_netfs.primary_index,
- &afs_cell_cache_index_def,
- cell, true);
-#endif
+ queue_work(afs_wq, &cell->manager);
- /* add to the cell lists */
- write_lock(&afs_cells_lock);
- list_add_tail(&cell->link, &afs_cells);
- write_unlock(&afs_cells_lock);
+wait_for_cell:
+ _debug("wait_for_cell");
+ ret = wait_on_bit(&cell->flags, AFS_CELL_FL_NOT_READY, TASK_INTERRUPTIBLE);
+ smp_rmb();
- down_write(&afs_proc_cells_sem);
- list_add_tail(&cell->proc_link, &afs_proc_cells);
- up_write(&afs_proc_cells_sem);
- up_write(&afs_cells_sem);
+ switch (READ_ONCE(cell->state)) {
+ case AFS_CELL_FAILED:
+ ret = cell->error;
+ goto error;
+ default:
+ _debug("weird %u %d", cell->state, cell->error);
+ goto error;
+ case AFS_CELL_ACTIVE:
+ break;
+ }
- _leave(" = %p", cell);
+ _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:
- up_write(&afs_cells_sem);
- key_put(cell->anonymous_key);
- kfree(cell);
- _leave(" = %d", ret);
+ afs_put_cell(net, cell);
+error_noput:
+ _leave(" = %d [error]", ret);
return ERR_PTR(ret);
-
-duplicate_name:
- if (retref && !IS_ERR(cell))
- afs_get_cell(cell);
-
- read_unlock(&afs_cells_lock);
- up_write(&afs_cells_sem);
-
- if (retref) {
- _leave(" = %p", cell);
- return cell;
- }
-
- _leave(" = -EEXIST");
- return ERR_PTR(-EEXIST);
}
/*
@@ -223,10 +306,11 @@ duplicate_name:
* - can be called with a module parameter string
* - can be called from a write to /proc/fs/afs/rootcell
*/
-int afs_cell_init(char *rootcell)
+int afs_cell_init(struct afs_net *net, const char *rootcell)
{
struct afs_cell *old_root, *new_root;
- char *cp;
+ const char *cp, *vllist;
+ size_t len;
_enter("");
@@ -239,222 +323,453 @@ int afs_cell_init(char *rootcell)
}
cp = strchr(rootcell, ':');
- if (!cp)
+ if (!cp) {
_debug("kAFS: no VL server IP addresses specified");
- else
- *cp++ = 0;
+ vllist = NULL;
+ len = strlen(rootcell);
+ } else {
+ vllist = cp + 1;
+ len = cp - rootcell;
+ }
/* allocate a cell record for the root cell */
- new_root = afs_cell_create(rootcell, strlen(rootcell), cp, false);
+ 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);
}
+ set_bit(AFS_CELL_FL_NO_GC, &new_root->flags);
+ afs_get_cell(new_root);
+
/* install the new cell */
- write_lock(&afs_cells_lock);
- old_root = afs_cell_root;
- afs_cell_root = new_root;
- write_unlock(&afs_cells_lock);
- afs_put_cell(old_root);
+ write_seqlock(&net->cells_lock);
+ old_root = net->ws_cell;
+ net->ws_cell = new_root;
+ write_sequnlock(&net->cells_lock);
+ afs_put_cell(net, old_root);
_leave(" = 0");
return 0;
}
/*
- * lookup a cell record
+ * Update a cell's VL server address list from the DNS.
*/
-struct afs_cell *afs_cell_lookup(const char *name, unsigned namesz,
- bool dns_cell)
+static void afs_update_cell(struct afs_cell *cell)
{
- struct afs_cell *cell;
-
- _enter("\"%*.*s\",", namesz, namesz, name ?: "");
-
- down_read(&afs_cells_sem);
- read_lock(&afs_cells_lock);
-
- if (name) {
- /* if the cell was named, look for it in the cell record list */
- list_for_each_entry(cell, &afs_cells, link) {
- if (strncmp(cell->name, name, namesz) == 0) {
- afs_get_cell(cell);
- goto found;
- }
+ struct afs_addr_list *alist, *old;
+ time64_t now, expiry;
+
+ _enter("%s", cell->name);
+
+ alist = afs_dns_query(cell, &expiry);
+ if (IS_ERR(alist)) {
+ switch (PTR_ERR(alist)) {
+ case -ENODATA:
+ /* The DNS said that the cell does not exist */
+ set_bit(AFS_CELL_FL_NOT_FOUND, &cell->flags);
+ clear_bit(AFS_CELL_FL_DNS_FAIL, &cell->flags);
+ cell->dns_expiry = ktime_get_real_seconds() + 61;
+ break;
+
+ case -EAGAIN:
+ case -ECONNREFUSED:
+ default:
+ set_bit(AFS_CELL_FL_DNS_FAIL, &cell->flags);
+ cell->dns_expiry = ktime_get_real_seconds() + 10;
+ break;
}
- cell = ERR_PTR(-ENOENT);
- if (dns_cell)
- goto create_cell;
- found:
- ;
+
+ cell->error = -EDESTADDRREQ;
} else {
- cell = afs_cell_root;
- if (!cell) {
- /* this should not happen unless user tries to mount
- * when root cell is not set. Return an impossibly
- * bizarre errno to alert the user. Things like
- * ENOENT might be "more appropriate" but they happen
- * for other reasons.
- */
- cell = ERR_PTR(-EDESTADDRREQ);
- } else {
- afs_get_cell(cell);
- }
+ clear_bit(AFS_CELL_FL_DNS_FAIL, &cell->flags);
+ clear_bit(AFS_CELL_FL_NOT_FOUND, &cell->flags);
+
+ /* Exclusion on changing vl_addrs is achieved by a
+ * non-reentrant work item.
+ */
+ old = rcu_dereference_protected(cell->vl_addrs, true);
+ rcu_assign_pointer(cell->vl_addrs, alist);
+ cell->dns_expiry = expiry;
+ if (old)
+ afs_put_addrlist(old);
}
- read_unlock(&afs_cells_lock);
- up_read(&afs_cells_sem);
- _leave(" = %p", cell);
- return cell;
+ if (test_and_clear_bit(AFS_CELL_FL_NO_LOOKUP_YET, &cell->flags))
+ wake_up_bit(&cell->flags, AFS_CELL_FL_NO_LOOKUP_YET);
-create_cell:
- read_unlock(&afs_cells_lock);
- up_read(&afs_cells_sem);
+ now = ktime_get_real_seconds();
+ afs_set_cell_timer(cell->net, cell->dns_expiry - now);
+ _leave("");
+}
- cell = afs_cell_create(name, namesz, NULL, true);
+/*
+ * Destroy a cell record
+ */
+static void afs_cell_destroy(struct rcu_head *rcu)
+{
+ struct afs_cell *cell = container_of(rcu, struct afs_cell, rcu);
- _leave(" = %p", cell);
- return cell;
+ _enter("%p{%s}", cell, cell->name);
+
+ ASSERTCMP(atomic_read(&cell->usage), ==, 0);
+
+ afs_put_addrlist(cell->vl_addrs);
+ key_put(cell->anonymous_key);
+ kfree(cell);
+
+ _leave(" [destroyed]");
}
-#if 0
/*
- * try and get a cell record
+ * Queue the cell manager.
*/
-struct afs_cell *afs_get_cell_maybe(struct afs_cell *cell)
+static void afs_queue_cell_manager(struct afs_net *net)
{
- write_lock(&afs_cells_lock);
+ int outstanding = atomic_inc_return(&net->cells_outstanding);
- if (cell && !list_empty(&cell->link))
- afs_get_cell(cell);
- else
- cell = NULL;
+ _enter("%d", outstanding);
- write_unlock(&afs_cells_lock);
- return cell;
+ if (!queue_work(afs_wq, &net->cells_manager))
+ afs_dec_cells_outstanding(net);
}
-#endif /* 0 */
/*
- * destroy a cell record
+ * Cell management timer. We have an increment on cells_outstanding that we
+ * need to pass along to the work item.
*/
-void afs_put_cell(struct afs_cell *cell)
+void afs_cells_timer(struct timer_list *timer)
{
- if (!cell)
- return;
+ struct afs_net *net = container_of(timer, struct afs_net, cells_timer);
- _enter("%p{%d,%s}", cell, atomic_read(&cell->usage), cell->name);
+ _enter("");
+ if (!queue_work(afs_wq, &net->cells_manager))
+ afs_dec_cells_outstanding(net);
+}
- ASSERTCMP(atomic_read(&cell->usage), >, 0);
+/*
+ * Get a reference on a cell record.
+ */
+struct afs_cell *afs_get_cell(struct afs_cell *cell)
+{
+ atomic_inc(&cell->usage);
+ return cell;
+}
- /* to prevent a race, the decrement and the dequeue must be effectively
- * atomic */
- write_lock(&afs_cells_lock);
+/*
+ * 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 (likely(!atomic_dec_and_test(&cell->usage))) {
- write_unlock(&afs_cells_lock);
- _leave("");
+ if (!cell)
return;
- }
- ASSERT(list_empty(&cell->servers));
- ASSERT(list_empty(&cell->vl_list));
+ _enter("%s", cell->name);
- write_unlock(&afs_cells_lock);
+ now = ktime_get_real_seconds();
+ cell->last_inactive = now;
+ expire_delay = 0;
+ if (!test_bit(AFS_CELL_FL_DNS_FAIL, &cell->flags) &&
+ !test_bit(AFS_CELL_FL_NOT_FOUND, &cell->flags))
+ expire_delay = afs_cell_gc_delay;
- wake_up(&afs_cells_freeable_wq);
+ if (atomic_dec_return(&cell->usage) > 1)
+ return;
- _leave(" [unused]");
+ /* 'cell' may now be garbage collected. */
+ afs_set_cell_timer(net, expire_delay);
}
/*
- * destroy a cell record
- * - must be called with the afs_cells_sem write-locked
- * - cell->link should have been broken by the caller
+ * Allocate a key to use as a placeholder for anonymous user security.
*/
-static void afs_cell_destroy(struct afs_cell *cell)
+static int afs_alloc_anon_key(struct afs_cell *cell)
{
- _enter("%p{%d,%s}", cell, atomic_read(&cell->usage), cell->name);
+ struct key *key;
+ char keyname[4 + AFS_MAXCELLNAME + 1], *cp, *dp;
- ASSERTCMP(atomic_read(&cell->usage), >=, 0);
- ASSERT(list_empty(&cell->link));
+ /* Create a key to represent an anonymous user. */
+ memcpy(keyname, "afs@", 4);
+ dp = keyname + 4;
+ cp = cell->name;
+ do {
+ *dp++ = tolower(*cp);
+ } while (*cp++);
- /* wait for everyone to stop using the cell */
- if (atomic_read(&cell->usage) > 0) {
- DECLARE_WAITQUEUE(myself, current);
+ key = rxrpc_get_null_key(keyname);
+ if (IS_ERR(key))
+ return PTR_ERR(key);
- _debug("wait for cell %s", cell->name);
- set_current_state(TASK_UNINTERRUPTIBLE);
- add_wait_queue(&afs_cells_freeable_wq, &myself);
+ cell->anonymous_key = key;
- while (atomic_read(&cell->usage) > 0) {
- schedule();
- set_current_state(TASK_UNINTERRUPTIBLE);
- }
+ _debug("anon key %p{%x}",
+ cell->anonymous_key, key_serial(cell->anonymous_key));
+ return 0;
+}
- remove_wait_queue(&afs_cells_freeable_wq, &myself);
- set_current_state(TASK_RUNNING);
+/*
+ * Activate a cell.
+ */
+static int afs_activate_cell(struct afs_net *net, struct afs_cell *cell)
+{
+ int ret;
+
+ if (!cell->anonymous_key) {
+ ret = afs_alloc_anon_key(cell);
+ if (ret < 0)
+ return ret;
}
- _debug("cell dead");
- ASSERTCMP(atomic_read(&cell->usage), ==, 0);
- ASSERT(list_empty(&cell->servers));
- ASSERT(list_empty(&cell->vl_list));
+#ifdef CONFIG_AFS_FSCACHE
+ cell->cache = fscache_acquire_cookie(afs_cache_netfs.primary_index,
+ &afs_cell_cache_index_def,
+ cell, true);
+#endif
+ ret = afs_proc_cell_setup(net, cell);
+ if (ret < 0)
+ return ret;
+ spin_lock(&net->proc_cells_lock);
+ list_add_tail(&cell->proc_link, &net->proc_cells);
+ spin_unlock(&net->proc_cells_lock);
+ return 0;
+}
- afs_proc_cell_remove(cell);
+/*
+ * Deactivate a cell.
+ */
+static void afs_deactivate_cell(struct afs_net *net, struct afs_cell *cell)
+{
+ _enter("%s", cell->name);
+
+ afs_proc_cell_remove(net, cell);
- down_write(&afs_proc_cells_sem);
+ spin_lock(&net->proc_cells_lock);
list_del_init(&cell->proc_link);
- up_write(&afs_proc_cells_sem);
+ spin_unlock(&net->proc_cells_lock);
#ifdef CONFIG_AFS_FSCACHE
fscache_relinquish_cookie(cell->cache, 0);
+ cell->cache = NULL;
#endif
- key_put(cell->anonymous_key);
- kfree(cell);
- _leave(" [destroyed]");
+ _leave("");
}
/*
- * purge in-memory cell database on module unload or afs_init() failure
- * - the timeout daemon is stopped before calling this
+ * Manage a cell record, initialising and destroying it, maintaining its DNS
+ * records.
*/
-void afs_cell_purge(void)
+static void afs_manage_cell(struct work_struct *work)
{
- struct afs_cell *cell;
+ 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;
+ cell->state = AFS_CELL_UNSET;
+ goto again;
+
+ case AFS_CELL_UNSET:
+ cell->state = AFS_CELL_ACTIVATING;
+ goto again;
+
+ case AFS_CELL_ACTIVATING:
+ ret = afs_activate_cell(net, cell);
+ if (ret < 0)
+ goto activation_failed;
+
+ cell->state = AFS_CELL_ACTIVE;
+ smp_wmb();
+ clear_bit(AFS_CELL_FL_NOT_READY, &cell->flags);
+ wake_up_bit(&cell->flags, AFS_CELL_FL_NOT_READY);
+ goto again;
+
+ case AFS_CELL_ACTIVE:
+ if (atomic_read(&cell->usage) > 1) {
+ time64_t now = ktime_get_real_seconds();
+ if (cell->dns_expiry <= now && net->live)
+ afs_update_cell(cell);
+ goto done;
+ }
+ cell->state = AFS_CELL_DEACTIVATING;
+ goto again;
+
+ case AFS_CELL_DEACTIVATING:
+ set_bit(AFS_CELL_FL_NOT_READY, &cell->flags);
+ if (atomic_read(&cell->usage) > 1)
+ goto reverse_deactivation;
+ afs_deactivate_cell(net, cell);
+ cell->state = AFS_CELL_INACTIVE;
+ goto again;
+
+ default:
+ break;
+ }
+ _debug("bad state %u", cell->state);
+ BUG(); /* Unhandled state */
+
+activation_failed:
+ cell->error = ret;
+ afs_deactivate_cell(net, cell);
+
+ cell->state = AFS_CELL_FAILED;
+ smp_wmb();
+ if (test_and_clear_bit(AFS_CELL_FL_NOT_READY, &cell->flags))
+ wake_up_bit(&cell->flags, AFS_CELL_FL_NOT_READY);
+ goto again;
+
+reverse_deactivation:
+ cell->state = AFS_CELL_ACTIVE;
+ smp_wmb();
+ clear_bit(AFS_CELL_FL_NOT_READY, &cell->flags);
+ wake_up_bit(&cell->flags, AFS_CELL_FL_NOT_READY);
+ _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("");
- afs_put_cell(afs_cell_root);
+ /* 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);
- down_write(&afs_cells_sem);
+ 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;
- while (!list_empty(&afs_cells)) {
- cell = NULL;
+ usage = atomic_read(&cell->usage);
+ _debug("manage %s %u", cell->name, usage);
+
+ ASSERTCMP(usage, >=, 1);
- /* remove the next cell from the front of the list */
- write_lock(&afs_cells_lock);
+ 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) {
+ time64_t expire_at = cell->last_inactive;
+
+ if (!test_bit(AFS_CELL_FL_DNS_FAIL, &cell->flags) &&
+ !test_bit(AFS_CELL_FL_NOT_FOUND, &cell->flags))
+ expire_at += afs_cell_gc_delay;
+ if (purging || expire_at <= now)
+ sched_cell = true;
+ else if (expire_at < next_manage)
+ next_manage = expire_at;
+ }
- if (!list_empty(&afs_cells)) {
- cell = list_entry(afs_cells.next,
- struct afs_cell, link);
- list_del_init(&cell->link);
+ if (!purging) {
+ if (cell->dns_expiry <= now)
+ sched_cell = true;
+ else if (cell->dns_expiry <= next_manage)
+ next_manage = cell->dns_expiry;
}
- write_unlock(&afs_cells_lock);
+ if (sched_cell)
+ queue_work(afs_wq, &cell->manager);
+ }
+
+ read_sequnlock_excl(&net->cells_lock);
- if (cell) {
- _debug("PURGING CELL %s (%d)",
- cell->name, atomic_read(&cell->usage));
+ /* 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();
- /* now the cell should be left with no references */
- afs_cell_destroy(cell);
+ 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);
}
}
- up_write(&afs_cells_sem);
+ 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 = net->ws_cell;
+ 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_on_atomic_t(&net->cells_outstanding, atomic_t_wait,
+ TASK_UNINTERRUPTIBLE);
_leave("");
}
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.