// SPDX-License-Identifier: GPL-2.0-or-later
|
/* AFS server record management
|
*
|
* Copyright (C) 2002, 2007 Red Hat, Inc. All Rights Reserved.
|
* Written by David Howells (dhowells@redhat.com)
|
*/
|
|
#include <linux/sched.h>
|
#include <linux/slab.h>
|
#include "afs_fs.h"
|
#include "internal.h"
|
#include "protocol_yfs.h"
|
|
static unsigned afs_server_gc_delay = 10; /* Server record timeout in seconds */
|
static atomic_t afs_server_debug_id;
|
|
static struct afs_server *afs_maybe_use_server(struct afs_server *,
|
enum afs_server_trace);
|
static void __afs_put_server(struct afs_net *, struct afs_server *);
|
|
/*
|
* Find a server by one of its addresses.
|
*/
|
struct afs_server *afs_find_server(struct afs_net *net,
|
const struct sockaddr_rxrpc *srx)
|
{
|
const struct afs_addr_list *alist;
|
struct afs_server *server = NULL;
|
unsigned int i;
|
int seq = 0, diff;
|
|
rcu_read_lock();
|
|
do {
|
if (server)
|
afs_unuse_server_notime(net, server, afs_server_trace_put_find_rsq);
|
server = NULL;
|
read_seqbegin_or_lock(&net->fs_addr_lock, &seq);
|
|
if (srx->transport.family == AF_INET6) {
|
const struct sockaddr_in6 *a = &srx->transport.sin6, *b;
|
hlist_for_each_entry_rcu(server, &net->fs_addresses6, addr6_link) {
|
alist = rcu_dereference(server->addresses);
|
for (i = alist->nr_ipv4; i < alist->nr_addrs; i++) {
|
b = &alist->addrs[i].transport.sin6;
|
diff = ((u16 __force)a->sin6_port -
|
(u16 __force)b->sin6_port);
|
if (diff == 0)
|
diff = memcmp(&a->sin6_addr,
|
&b->sin6_addr,
|
sizeof(struct in6_addr));
|
if (diff == 0)
|
goto found;
|
}
|
}
|
} else {
|
const struct sockaddr_in *a = &srx->transport.sin, *b;
|
hlist_for_each_entry_rcu(server, &net->fs_addresses4, addr4_link) {
|
alist = rcu_dereference(server->addresses);
|
for (i = 0; i < alist->nr_ipv4; i++) {
|
b = &alist->addrs[i].transport.sin;
|
diff = ((u16 __force)a->sin_port -
|
(u16 __force)b->sin_port);
|
if (diff == 0)
|
diff = ((u32 __force)a->sin_addr.s_addr -
|
(u32 __force)b->sin_addr.s_addr);
|
if (diff == 0)
|
goto found;
|
}
|
}
|
}
|
|
server = NULL;
|
continue;
|
found:
|
server = afs_maybe_use_server(server, afs_server_trace_get_by_addr);
|
|
} while (need_seqretry(&net->fs_addr_lock, seq));
|
|
done_seqretry(&net->fs_addr_lock, seq);
|
|
rcu_read_unlock();
|
return server;
|
}
|
|
/*
|
* Look up a server by its UUID and mark it active.
|
*/
|
struct afs_server *afs_find_server_by_uuid(struct afs_net *net, const uuid_t *uuid)
|
{
|
struct afs_server *server = NULL;
|
struct rb_node *p;
|
int diff, seq = 0;
|
|
_enter("%pU", uuid);
|
|
do {
|
/* Unfortunately, rbtree walking doesn't give reliable results
|
* under just the RCU read lock, so we have to check for
|
* changes.
|
*/
|
if (server)
|
afs_unuse_server(net, server, afs_server_trace_put_uuid_rsq);
|
server = NULL;
|
|
read_seqbegin_or_lock(&net->fs_lock, &seq);
|
|
p = net->fs_servers.rb_node;
|
while (p) {
|
server = rb_entry(p, struct afs_server, uuid_rb);
|
|
diff = memcmp(uuid, &server->uuid, sizeof(*uuid));
|
if (diff < 0) {
|
p = p->rb_left;
|
} else if (diff > 0) {
|
p = p->rb_right;
|
} else {
|
afs_use_server(server, afs_server_trace_get_by_uuid);
|
break;
|
}
|
|
server = NULL;
|
}
|
} while (need_seqretry(&net->fs_lock, seq));
|
|
done_seqretry(&net->fs_lock, seq);
|
|
_leave(" = %p", server);
|
return server;
|
}
|
|
/*
|
* Install a server record in the namespace tree. If there's a clash, we stick
|
* it into a list anchored on whichever afs_server struct is actually in the
|
* tree.
|
*/
|
static struct afs_server *afs_install_server(struct afs_cell *cell,
|
struct afs_server *candidate)
|
{
|
const struct afs_addr_list *alist;
|
struct afs_server *server, *next;
|
struct afs_net *net = cell->net;
|
struct rb_node **pp, *p;
|
int diff;
|
|
_enter("%p", candidate);
|
|
write_seqlock(&net->fs_lock);
|
|
/* Firstly install the server in the UUID lookup tree */
|
pp = &net->fs_servers.rb_node;
|
p = NULL;
|
while (*pp) {
|
p = *pp;
|
_debug("- consider %p", p);
|
server = rb_entry(p, struct afs_server, uuid_rb);
|
diff = memcmp(&candidate->uuid, &server->uuid, sizeof(uuid_t));
|
if (diff < 0) {
|
pp = &(*pp)->rb_left;
|
} else if (diff > 0) {
|
pp = &(*pp)->rb_right;
|
} else {
|
if (server->cell == cell)
|
goto exists;
|
|
/* We have the same UUID representing servers in
|
* different cells. Append the new server to the list.
|
*/
|
for (;;) {
|
next = rcu_dereference_protected(
|
server->uuid_next,
|
lockdep_is_held(&net->fs_lock.lock));
|
if (!next)
|
break;
|
server = next;
|
}
|
rcu_assign_pointer(server->uuid_next, candidate);
|
candidate->uuid_prev = server;
|
server = candidate;
|
goto added_dup;
|
}
|
}
|
|
server = candidate;
|
rb_link_node(&server->uuid_rb, p, pp);
|
rb_insert_color(&server->uuid_rb, &net->fs_servers);
|
hlist_add_head_rcu(&server->proc_link, &net->fs_proc);
|
|
added_dup:
|
write_seqlock(&net->fs_addr_lock);
|
alist = rcu_dereference_protected(server->addresses,
|
lockdep_is_held(&net->fs_addr_lock.lock));
|
|
/* Secondly, if the server has any IPv4 and/or IPv6 addresses, install
|
* it in the IPv4 and/or IPv6 reverse-map lists.
|
*
|
* TODO: For speed we want to use something other than a flat list
|
* here; even sorting the list in terms of lowest address would help a
|
* bit, but anything we might want to do gets messy and memory
|
* intensive.
|
*/
|
if (alist->nr_ipv4 > 0)
|
hlist_add_head_rcu(&server->addr4_link, &net->fs_addresses4);
|
if (alist->nr_addrs > alist->nr_ipv4)
|
hlist_add_head_rcu(&server->addr6_link, &net->fs_addresses6);
|
|
write_sequnlock(&net->fs_addr_lock);
|
|
exists:
|
afs_get_server(server, afs_server_trace_get_install);
|
write_sequnlock(&net->fs_lock);
|
return server;
|
}
|
|
/*
|
* Allocate a new server record and mark it active.
|
*/
|
static struct afs_server *afs_alloc_server(struct afs_cell *cell,
|
const uuid_t *uuid,
|
struct afs_addr_list *alist)
|
{
|
struct afs_server *server;
|
struct afs_net *net = cell->net;
|
|
_enter("");
|
|
server = kzalloc(sizeof(struct afs_server), GFP_KERNEL);
|
if (!server)
|
goto enomem;
|
|
atomic_set(&server->ref, 1);
|
atomic_set(&server->active, 1);
|
server->debug_id = atomic_inc_return(&afs_server_debug_id);
|
RCU_INIT_POINTER(server->addresses, alist);
|
server->addr_version = alist->version;
|
server->uuid = *uuid;
|
rwlock_init(&server->fs_lock);
|
init_waitqueue_head(&server->probe_wq);
|
INIT_LIST_HEAD(&server->probe_link);
|
spin_lock_init(&server->probe_lock);
|
server->cell = cell;
|
server->rtt = UINT_MAX;
|
|
afs_inc_servers_outstanding(net);
|
trace_afs_server(server, 1, 1, afs_server_trace_alloc);
|
_leave(" = %p", server);
|
return server;
|
|
enomem:
|
_leave(" = NULL [nomem]");
|
return NULL;
|
}
|
|
/*
|
* Look up an address record for a server
|
*/
|
static struct afs_addr_list *afs_vl_lookup_addrs(struct afs_cell *cell,
|
struct key *key, const uuid_t *uuid)
|
{
|
struct afs_vl_cursor vc;
|
struct afs_addr_list *alist = NULL;
|
int ret;
|
|
ret = -ERESTARTSYS;
|
if (afs_begin_vlserver_operation(&vc, cell, key)) {
|
while (afs_select_vlserver(&vc)) {
|
if (test_bit(AFS_VLSERVER_FL_IS_YFS, &vc.server->flags))
|
alist = afs_yfsvl_get_endpoints(&vc, uuid);
|
else
|
alist = afs_vl_get_addrs_u(&vc, uuid);
|
}
|
|
ret = afs_end_vlserver_operation(&vc);
|
}
|
|
return ret < 0 ? ERR_PTR(ret) : alist;
|
}
|
|
/*
|
* Get or create a fileserver record.
|
*/
|
struct afs_server *afs_lookup_server(struct afs_cell *cell, struct key *key,
|
const uuid_t *uuid, u32 addr_version)
|
{
|
struct afs_addr_list *alist;
|
struct afs_server *server, *candidate;
|
|
_enter("%p,%pU", cell->net, uuid);
|
|
server = afs_find_server_by_uuid(cell->net, uuid);
|
if (server) {
|
if (server->addr_version != addr_version)
|
set_bit(AFS_SERVER_FL_NEEDS_UPDATE, &server->flags);
|
return server;
|
}
|
|
alist = afs_vl_lookup_addrs(cell, key, uuid);
|
if (IS_ERR(alist))
|
return ERR_CAST(alist);
|
|
candidate = afs_alloc_server(cell, uuid, alist);
|
if (!candidate) {
|
afs_put_addrlist(alist);
|
return ERR_PTR(-ENOMEM);
|
}
|
|
server = afs_install_server(cell, candidate);
|
if (server != candidate) {
|
afs_put_addrlist(alist);
|
kfree(candidate);
|
} else {
|
/* Immediately dispatch an asynchronous probe to each interface
|
* on the fileserver. This will make sure the repeat-probing
|
* service is started.
|
*/
|
afs_fs_probe_fileserver(cell->net, server, key, true);
|
}
|
|
return server;
|
}
|
|
/*
|
* Set the server timer to fire after a given delay, assuming it's not already
|
* set for an earlier time.
|
*/
|
static void afs_set_server_timer(struct afs_net *net, time64_t delay)
|
{
|
if (net->live) {
|
afs_inc_servers_outstanding(net);
|
if (timer_reduce(&net->fs_timer, jiffies + delay * HZ))
|
afs_dec_servers_outstanding(net);
|
}
|
}
|
|
/*
|
* Server management timer. We have an increment on fs_outstanding that we
|
* need to pass along to the work item.
|
*/
|
void afs_servers_timer(struct timer_list *timer)
|
{
|
struct afs_net *net = container_of(timer, struct afs_net, fs_timer);
|
|
_enter("");
|
if (!queue_work(afs_wq, &net->fs_manager))
|
afs_dec_servers_outstanding(net);
|
}
|
|
/*
|
* Get a reference on a server object.
|
*/
|
struct afs_server *afs_get_server(struct afs_server *server,
|
enum afs_server_trace reason)
|
{
|
unsigned int u = atomic_inc_return(&server->ref);
|
|
trace_afs_server(server, u, atomic_read(&server->active), reason);
|
return server;
|
}
|
|
/*
|
* Try to get a reference on a server object.
|
*/
|
static struct afs_server *afs_maybe_use_server(struct afs_server *server,
|
enum afs_server_trace reason)
|
{
|
unsigned int r = atomic_fetch_add_unless(&server->ref, 1, 0);
|
unsigned int a;
|
|
if (r == 0)
|
return NULL;
|
|
a = atomic_inc_return(&server->active);
|
trace_afs_server(server, r, a, reason);
|
return server;
|
}
|
|
/*
|
* Get an active count on a server object.
|
*/
|
struct afs_server *afs_use_server(struct afs_server *server, enum afs_server_trace reason)
|
{
|
unsigned int r = atomic_inc_return(&server->ref);
|
unsigned int a = atomic_inc_return(&server->active);
|
|
trace_afs_server(server, r, a, reason);
|
return server;
|
}
|
|
/*
|
* Release a reference on a server record.
|
*/
|
void afs_put_server(struct afs_net *net, struct afs_server *server,
|
enum afs_server_trace reason)
|
{
|
unsigned int usage;
|
|
if (!server)
|
return;
|
|
usage = atomic_dec_return(&server->ref);
|
trace_afs_server(server, usage, atomic_read(&server->active), reason);
|
if (unlikely(usage == 0))
|
__afs_put_server(net, server);
|
}
|
|
/*
|
* Drop an active count on a server object without updating the last-unused
|
* time.
|
*/
|
void afs_unuse_server_notime(struct afs_net *net, struct afs_server *server,
|
enum afs_server_trace reason)
|
{
|
if (server) {
|
unsigned int active = atomic_dec_return(&server->active);
|
|
if (active == 0)
|
afs_set_server_timer(net, afs_server_gc_delay);
|
afs_put_server(net, server, reason);
|
}
|
}
|
|
/*
|
* Drop an active count on a server object.
|
*/
|
void afs_unuse_server(struct afs_net *net, struct afs_server *server,
|
enum afs_server_trace reason)
|
{
|
if (server) {
|
server->unuse_time = ktime_get_real_seconds();
|
afs_unuse_server_notime(net, server, reason);
|
}
|
}
|
|
static void afs_server_rcu(struct rcu_head *rcu)
|
{
|
struct afs_server *server = container_of(rcu, struct afs_server, rcu);
|
|
trace_afs_server(server, atomic_read(&server->ref),
|
atomic_read(&server->active), afs_server_trace_free);
|
afs_put_addrlist(rcu_access_pointer(server->addresses));
|
kfree(server);
|
}
|
|
static void __afs_put_server(struct afs_net *net, struct afs_server *server)
|
{
|
call_rcu(&server->rcu, afs_server_rcu);
|
afs_dec_servers_outstanding(net);
|
}
|
|
static void afs_give_up_callbacks(struct afs_net *net, struct afs_server *server)
|
{
|
struct afs_addr_list *alist = rcu_access_pointer(server->addresses);
|
struct afs_addr_cursor ac = {
|
.alist = alist,
|
.index = alist->preferred,
|
.error = 0,
|
};
|
|
afs_fs_give_up_all_callbacks(net, server, &ac, NULL);
|
}
|
|
/*
|
* destroy a dead server
|
*/
|
static void afs_destroy_server(struct afs_net *net, struct afs_server *server)
|
{
|
if (test_bit(AFS_SERVER_FL_MAY_HAVE_CB, &server->flags))
|
afs_give_up_callbacks(net, server);
|
|
afs_put_server(net, server, afs_server_trace_destroy);
|
}
|
|
/*
|
* Garbage collect any expired servers.
|
*/
|
static void afs_gc_servers(struct afs_net *net, struct afs_server *gc_list)
|
{
|
struct afs_server *server, *next, *prev;
|
int active;
|
|
while ((server = gc_list)) {
|
gc_list = server->gc_next;
|
|
write_seqlock(&net->fs_lock);
|
|
active = atomic_read(&server->active);
|
if (active == 0) {
|
trace_afs_server(server, atomic_read(&server->ref),
|
active, afs_server_trace_gc);
|
next = rcu_dereference_protected(
|
server->uuid_next, lockdep_is_held(&net->fs_lock.lock));
|
prev = server->uuid_prev;
|
if (!prev) {
|
/* The one at the front is in the tree */
|
if (!next) {
|
rb_erase(&server->uuid_rb, &net->fs_servers);
|
} else {
|
rb_replace_node_rcu(&server->uuid_rb,
|
&next->uuid_rb,
|
&net->fs_servers);
|
next->uuid_prev = NULL;
|
}
|
} else {
|
/* This server is not at the front */
|
rcu_assign_pointer(prev->uuid_next, next);
|
if (next)
|
next->uuid_prev = prev;
|
}
|
|
list_del(&server->probe_link);
|
hlist_del_rcu(&server->proc_link);
|
if (!hlist_unhashed(&server->addr4_link))
|
hlist_del_rcu(&server->addr4_link);
|
if (!hlist_unhashed(&server->addr6_link))
|
hlist_del_rcu(&server->addr6_link);
|
}
|
write_sequnlock(&net->fs_lock);
|
|
if (active == 0)
|
afs_destroy_server(net, server);
|
}
|
}
|
|
/*
|
* Manage the records of servers known to be within a network namespace. This
|
* includes garbage collecting unused servers.
|
*
|
* Note also that we were given an increment on net->servers_outstanding by
|
* whoever queued us that we need to deal with before returning.
|
*/
|
void afs_manage_servers(struct work_struct *work)
|
{
|
struct afs_net *net = container_of(work, struct afs_net, fs_manager);
|
struct afs_server *gc_list = NULL;
|
struct rb_node *cursor;
|
time64_t now = ktime_get_real_seconds(), next_manage = TIME64_MAX;
|
bool purging = !net->live;
|
|
_enter("");
|
|
/* Trawl the server list looking for servers that have expired from
|
* lack of use.
|
*/
|
read_seqlock_excl(&net->fs_lock);
|
|
for (cursor = rb_first(&net->fs_servers); cursor; cursor = rb_next(cursor)) {
|
struct afs_server *server =
|
rb_entry(cursor, struct afs_server, uuid_rb);
|
int active = atomic_read(&server->active);
|
|
_debug("manage %pU %u", &server->uuid, active);
|
|
if (purging) {
|
trace_afs_server(server, atomic_read(&server->ref),
|
active, afs_server_trace_purging);
|
if (active != 0)
|
pr_notice("Can't purge s=%08x\n", server->debug_id);
|
}
|
|
if (active == 0) {
|
time64_t expire_at = server->unuse_time;
|
|
if (!test_bit(AFS_SERVER_FL_VL_FAIL, &server->flags) &&
|
!test_bit(AFS_SERVER_FL_NOT_FOUND, &server->flags))
|
expire_at += afs_server_gc_delay;
|
if (purging || expire_at <= now) {
|
server->gc_next = gc_list;
|
gc_list = server;
|
} else if (expire_at < next_manage) {
|
next_manage = expire_at;
|
}
|
}
|
}
|
|
read_sequnlock_excl(&net->fs_lock);
|
|
/* Update the timer on the way out. We have to pass an increment on
|
* servers_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->fs_manager))
|
afs_inc_servers_outstanding(net);
|
} else {
|
afs_set_server_timer(net, next_manage - now);
|
}
|
}
|
|
afs_gc_servers(net, gc_list);
|
|
afs_dec_servers_outstanding(net);
|
_leave(" [%d]", atomic_read(&net->servers_outstanding));
|
}
|
|
static void afs_queue_server_manager(struct afs_net *net)
|
{
|
afs_inc_servers_outstanding(net);
|
if (!queue_work(afs_wq, &net->fs_manager))
|
afs_dec_servers_outstanding(net);
|
}
|
|
/*
|
* Purge list of servers.
|
*/
|
void afs_purge_servers(struct afs_net *net)
|
{
|
_enter("");
|
|
if (del_timer_sync(&net->fs_timer))
|
afs_dec_servers_outstanding(net);
|
|
afs_queue_server_manager(net);
|
|
_debug("wait");
|
atomic_dec(&net->servers_outstanding);
|
wait_var_event(&net->servers_outstanding,
|
!atomic_read(&net->servers_outstanding));
|
_leave("");
|
}
|
|
/*
|
* Get an update for a server's address list.
|
*/
|
static noinline bool afs_update_server_record(struct afs_operation *op,
|
struct afs_server *server)
|
{
|
struct afs_addr_list *alist, *discard;
|
|
_enter("");
|
|
trace_afs_server(server, atomic_read(&server->ref), atomic_read(&server->active),
|
afs_server_trace_update);
|
|
alist = afs_vl_lookup_addrs(op->volume->cell, op->key, &server->uuid);
|
if (IS_ERR(alist)) {
|
if ((PTR_ERR(alist) == -ERESTARTSYS ||
|
PTR_ERR(alist) == -EINTR) &&
|
(op->flags & AFS_OPERATION_UNINTR) &&
|
server->addresses) {
|
_leave(" = t [intr]");
|
return true;
|
}
|
op->error = PTR_ERR(alist);
|
_leave(" = f [%d]", op->error);
|
return false;
|
}
|
|
discard = alist;
|
if (server->addr_version != alist->version) {
|
write_lock(&server->fs_lock);
|
discard = rcu_dereference_protected(server->addresses,
|
lockdep_is_held(&server->fs_lock));
|
rcu_assign_pointer(server->addresses, alist);
|
server->addr_version = alist->version;
|
write_unlock(&server->fs_lock);
|
}
|
|
afs_put_addrlist(discard);
|
_leave(" = t");
|
return true;
|
}
|
|
/*
|
* See if a server's address list needs updating.
|
*/
|
bool afs_check_server_record(struct afs_operation *op, struct afs_server *server)
|
{
|
bool success;
|
int ret, retries = 0;
|
|
_enter("");
|
|
ASSERT(server);
|
|
retry:
|
if (test_bit(AFS_SERVER_FL_UPDATING, &server->flags))
|
goto wait;
|
if (test_bit(AFS_SERVER_FL_NEEDS_UPDATE, &server->flags))
|
goto update;
|
_leave(" = t [good]");
|
return true;
|
|
update:
|
if (!test_and_set_bit_lock(AFS_SERVER_FL_UPDATING, &server->flags)) {
|
clear_bit(AFS_SERVER_FL_NEEDS_UPDATE, &server->flags);
|
success = afs_update_server_record(op, server);
|
clear_bit_unlock(AFS_SERVER_FL_UPDATING, &server->flags);
|
wake_up_bit(&server->flags, AFS_SERVER_FL_UPDATING);
|
_leave(" = %d", success);
|
return success;
|
}
|
|
wait:
|
ret = wait_on_bit(&server->flags, AFS_SERVER_FL_UPDATING,
|
(op->flags & AFS_OPERATION_UNINTR) ?
|
TASK_UNINTERRUPTIBLE : TASK_INTERRUPTIBLE);
|
if (ret == -ERESTARTSYS) {
|
op->error = ret;
|
_leave(" = f [intr]");
|
return false;
|
}
|
|
retries++;
|
if (retries == 4) {
|
_leave(" = f [stale]");
|
ret = -ESTALE;
|
return false;
|
}
|
goto retry;
|
}
|
