// SPDX-License-Identifier: GPL-2.0-or-later
/* AFS vlserver probing
*
* Copyright (C) 2018 Red Hat, Inc. All Rights Reserved.
* Written by David Howells ([email protected])
*/
#include <linux/sched.h>
#include <linux/slab.h>
#include "afs_fs.h"
#include "internal.h"
#include "protocol_yfs.h"
/*
* Handle the completion of a set of probes.
*/
static void afs_finished_vl_probe(struct afs_vlserver *server)
{
if (!(server->probe.flags & AFS_VLSERVER_PROBE_RESPONDED)) {
server->rtt = UINT_MAX;
clear_bit(AFS_VLSERVER_FL_RESPONDING, &server->flags);
}
clear_bit_unlock(AFS_VLSERVER_FL_PROBING, &server->flags);
wake_up_bit(&server->flags, AFS_VLSERVER_FL_PROBING);
}
/*
* Handle the completion of a probe RPC call.
*/
static void afs_done_one_vl_probe(struct afs_vlserver *server, bool wake_up)
{
if (atomic_dec_and_test(&server->probe_outstanding)) {
afs_finished_vl_probe(server);
wake_up = true;
}
if (wake_up)
wake_up_all(&server->probe_wq);
}
/*
* Process the result of probing a vlserver. This is called after successful
* or failed delivery of an VL.GetCapabilities operation.
*/
void afs_vlserver_probe_result(struct afs_call *call)
{
struct afs_addr_list *alist = call->vl_probe;
struct afs_vlserver *server = call->vlserver;
struct afs_address *addr = &alist->addrs[call->probe_index];
unsigned int server_index = call->server_index;
unsigned int rtt_us = 0;
unsigned int index = call->probe_index;
bool have_result = false;
int ret = call->error;
_enter("%s,%u,%u,%d,%d", server->name, server_index, index, ret, call->abort_code);
spin_lock(&server->probe_lock);
switch (ret) {
case 0:
server->probe.error = 0;
goto responded;
case -ECONNABORTED:
if (!(server->probe.flags & AFS_VLSERVER_PROBE_RESPONDED)) {
server->probe.abort_code = call->abort_code;
server->probe.error = ret;
}
goto responded;
case -ENOMEM:
case -ENONET:
case -EKEYEXPIRED:
case -EKEYREVOKED:
case -EKEYREJECTED:
server->probe.flags |= AFS_VLSERVER_PROBE_LOCAL_FAILURE;
if (server->probe.error == 0)
server->probe.error = ret;
trace_afs_io_error(call->debug_id, ret, afs_io_error_vl_probe_fail);
goto out;
case -ECONNRESET: /* Responded, but call expired. */
case -ERFKILL:
case -EADDRNOTAVAIL:
case -ENETUNREACH:
case -EHOSTUNREACH:
case -EHOSTDOWN:
case -ECONNREFUSED:
case -ETIMEDOUT:
case -ETIME:
default:
clear_bit(index, &alist->responded);
set_bit(index, &alist->probe_failed);
if (!(server->probe.flags & AFS_VLSERVER_PROBE_RESPONDED) &&
(server->probe.error == 0 ||
server->probe.error == -ETIMEDOUT ||
server->probe.error == -ETIME))
server->probe.error = ret;
trace_afs_io_error(call->debug_id, ret, afs_io_error_vl_probe_fail);
goto out;
}
responded:
set_bit(index, &alist->responded);
clear_bit(index, &alist->probe_failed);
if (call->service_id == YFS_VL_SERVICE) {
server->probe.flags |= AFS_VLSERVER_PROBE_IS_YFS;
set_bit(AFS_VLSERVER_FL_IS_YFS, &server->flags);
server->service_id = call->service_id;
} else {
server->probe.flags |= AFS_VLSERVER_PROBE_NOT_YFS;
if (!(server->probe.flags & AFS_VLSERVER_PROBE_IS_YFS)) {
clear_bit(AFS_VLSERVER_FL_IS_YFS, &server->flags);
server->service_id = call->service_id;
}
}
rtt_us = rxrpc_kernel_get_srtt(addr->peer);
if (rtt_us < server->probe.rtt) {
server->probe.rtt = rtt_us;
server->rtt = rtt_us;
alist->preferred = index;
}
smp_wmb(); /* Set rtt before responded. */
server->probe.flags |= AFS_VLSERVER_PROBE_RESPONDED;
set_bit(AFS_VLSERVER_FL_PROBED, &server->flags);
set_bit(AFS_VLSERVER_FL_RESPONDING, &server->flags);
have_result = true;
out:
spin_unlock(&server->probe_lock);
trace_afs_vl_probe(server, false, alist, index, call->error, call->abort_code, rtt_us);
_debug("probe [%u][%u] %pISpc rtt=%d ret=%d",
server_index, index, rxrpc_kernel_remote_addr(addr->peer),
rtt_us, ret);
afs_done_one_vl_probe(server, have_result);
}
/*
* Probe all of a vlserver's addresses to find out the best route and to
* query its capabilities.
*/
static bool afs_do_probe_vlserver(struct afs_net *net,
struct afs_vlserver *server,
struct key *key,
unsigned int server_index,
struct afs_error *_e)
{
struct afs_addr_list *alist;
struct afs_call *call;
unsigned long unprobed;
unsigned int index, i;
bool in_progress = false;
int best_prio;
_enter("%s", server->name);
read_lock(&server->lock);
alist = rcu_dereference_protected(server->addresses,
lockdep_is_held(&server->lock));
afs_get_addrlist(alist, afs_alist_trace_get_vlprobe);
read_unlock(&server->lock);
atomic_set(&server->probe_outstanding, alist->nr_addrs);
memset(&server->probe, 0, sizeof(server->probe));
server->probe.rtt = UINT_MAX;
unprobed = (1UL << alist->nr_addrs) - 1;
while (unprobed) {
best_prio = -1;
index = 0;
for (i = 0; i < alist->nr_addrs; i++) {
if (test_bit(i, &unprobed) &&
alist->addrs[i].prio > best_prio) {
index = i;
best_prio = alist->addrs[i].prio;
}
}
__clear_bit(index, &unprobed);
trace_afs_vl_probe(server, true, alist, index, 0, 0, 0);
call = afs_vl_get_capabilities(net, alist, index, key, server,
server_index);
if (!IS_ERR(call)) {
afs_prioritise_error(_e, call->error, call->abort_code);
afs_put_call(call);
in_progress = true;
} else {
afs_prioritise_error(_e, PTR_ERR(call), 0);
afs_done_one_vl_probe(server, false);
}
}
afs_put_addrlist(alist, afs_alist_trace_put_vlprobe);
return in_progress;
}
/*
* Send off probes to all unprobed servers.
*/
int afs_send_vl_probes(struct afs_net *net, struct key *key,
struct afs_vlserver_list *vllist)
{
struct afs_vlserver *server;
struct afs_error e = {};
bool in_progress = false;
int i;
for (i = 0; i < vllist->nr_servers; i++) {
server = vllist->servers[i].server;
if (test_bit(AFS_VLSERVER_FL_PROBED, &server->flags))
continue;
if (!test_and_set_bit_lock(AFS_VLSERVER_FL_PROBING, &server->flags) &&
afs_do_probe_vlserver(net, server, key, i, &e))
in_progress = true;
}
return in_progress ? 0 : e.error;
}
/*
* Wait for the first as-yet untried server to respond.
*/
int afs_wait_for_vl_probes(struct afs_vlserver_list *vllist,
unsigned long untried)
{
struct wait_queue_entry *waits;
struct afs_vlserver *server;
unsigned int rtt = UINT_MAX, rtt_s;
bool have_responders = false;
int pref = -1, i;
_enter("%u,%lx", vllist->nr_servers, untried);
/* Only wait for servers that have a probe outstanding. */
for (i = 0; i < vllist->nr_servers; i++) {
if (test_bit(i, &untried)) {
server = vllist->servers[i].server;
if (!test_bit(AFS_VLSERVER_FL_PROBING, &server->flags))
__clear_bit(i, &untried);
if (server->probe.flags & AFS_VLSERVER_PROBE_RESPONDED)
have_responders = true;
}
}
if (have_responders || !untried)
return 0;
waits = kmalloc(array_size(vllist->nr_servers, sizeof(*waits)), GFP_KERNEL);
if (!waits)
return -ENOMEM;
for (i = 0; i < vllist->nr_servers; i++) {
if (test_bit(i, &untried)) {
server = vllist->servers[i].server;
init_waitqueue_entry(&waits[i], current);
add_wait_queue(&server->probe_wq, &waits[i]);
}
}
for (;;) {
bool still_probing = false;
set_current_state(TASK_INTERRUPTIBLE);
for (i = 0; i < vllist->nr_servers; i++) {
if (test_bit(i, &untried)) {
server = vllist->servers[i].server;
if (server->probe.flags & AFS_VLSERVER_PROBE_RESPONDED)
goto stop;
if (test_bit(AFS_VLSERVER_FL_PROBING, &server->flags))
still_probing = true;
}
}
if (!still_probing || signal_pending(current))
goto stop;
schedule();
}
stop:
set_current_state(TASK_RUNNING);
for (i = 0; i < vllist->nr_servers; i++) {
if (test_bit(i, &untried)) {
server = vllist->servers[i].server;
rtt_s = READ_ONCE(server->rtt);
if (test_bit(AFS_VLSERVER_FL_RESPONDING, &server->flags) &&
rtt_s < rtt) {
pref = i;
rtt = rtt_s;
}
remove_wait_queue(&server->probe_wq, &waits[i]);
}
}
kfree(waits);
if (pref == -1 && signal_pending(current))
return -ERESTARTSYS;
if (pref >= 0)
vllist->preferred = pref;
_leave(" = 0 [%u]", pref);
return 0;
}
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