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1// SPDX-License-Identifier: GPL-2.0-or-later2/* AFS vlserver probing3 *4 * Copyright (C) 2018 Red Hat, Inc. All Rights Reserved.5 * Written by David Howells (dhowells@redhat.com)6 */7 8#include <linux/sched.h>9#include <linux/slab.h>10#include "afs_fs.h"11#include "internal.h"12#include "protocol_yfs.h"13 14 15/*16 * Handle the completion of a set of probes.17 */18static void afs_finished_vl_probe(struct afs_vlserver *server)19{20 if (!(server->probe.flags & AFS_VLSERVER_PROBE_RESPONDED)) {21 server->rtt = UINT_MAX;22 clear_bit(AFS_VLSERVER_FL_RESPONDING, &server->flags);23 }24 25 clear_bit_unlock(AFS_VLSERVER_FL_PROBING, &server->flags);26 wake_up_bit(&server->flags, AFS_VLSERVER_FL_PROBING);27}28 29/*30 * Handle the completion of a probe RPC call.31 */32static void afs_done_one_vl_probe(struct afs_vlserver *server, bool wake_up)33{34 if (atomic_dec_and_test(&server->probe_outstanding)) {35 afs_finished_vl_probe(server);36 wake_up = true;37 }38 39 if (wake_up)40 wake_up_all(&server->probe_wq);41}42 43/*44 * Process the result of probing a vlserver. This is called after successful45 * or failed delivery of an VL.GetCapabilities operation.46 */47void afs_vlserver_probe_result(struct afs_call *call)48{49 struct afs_addr_list *alist = call->vl_probe;50 struct afs_vlserver *server = call->vlserver;51 struct afs_address *addr = &alist->addrs[call->probe_index];52 unsigned int server_index = call->server_index;53 unsigned int rtt_us = 0;54 unsigned int index = call->probe_index;55 bool have_result = false;56 int ret = call->error;57 58 _enter("%s,%u,%u,%d,%d", server->name, server_index, index, ret, call->abort_code);59 60 spin_lock(&server->probe_lock);61 62 switch (ret) {63 case 0:64 server->probe.error = 0;65 goto responded;66 case -ECONNABORTED:67 if (!(server->probe.flags & AFS_VLSERVER_PROBE_RESPONDED)) {68 server->probe.abort_code = call->abort_code;69 server->probe.error = ret;70 }71 goto responded;72 case -ENOMEM:73 case -ENONET:74 case -EKEYEXPIRED:75 case -EKEYREVOKED:76 case -EKEYREJECTED:77 server->probe.flags |= AFS_VLSERVER_PROBE_LOCAL_FAILURE;78 if (server->probe.error == 0)79 server->probe.error = ret;80 trace_afs_io_error(call->debug_id, ret, afs_io_error_vl_probe_fail);81 goto out;82 case -ECONNRESET: /* Responded, but call expired. */83 case -ERFKILL:84 case -EADDRNOTAVAIL:85 case -ENETUNREACH:86 case -EHOSTUNREACH:87 case -EHOSTDOWN:88 case -ECONNREFUSED:89 case -ETIMEDOUT:90 case -ETIME:91 default:92 clear_bit(index, &alist->responded);93 set_bit(index, &alist->probe_failed);94 if (!(server->probe.flags & AFS_VLSERVER_PROBE_RESPONDED) &&95 (server->probe.error == 0 ||96 server->probe.error == -ETIMEDOUT ||97 server->probe.error == -ETIME))98 server->probe.error = ret;99 trace_afs_io_error(call->debug_id, ret, afs_io_error_vl_probe_fail);100 goto out;101 }102 103responded:104 set_bit(index, &alist->responded);105 clear_bit(index, &alist->probe_failed);106 107 if (call->service_id == YFS_VL_SERVICE) {108 server->probe.flags |= AFS_VLSERVER_PROBE_IS_YFS;109 set_bit(AFS_VLSERVER_FL_IS_YFS, &server->flags);110 server->service_id = call->service_id;111 } else {112 server->probe.flags |= AFS_VLSERVER_PROBE_NOT_YFS;113 if (!(server->probe.flags & AFS_VLSERVER_PROBE_IS_YFS)) {114 clear_bit(AFS_VLSERVER_FL_IS_YFS, &server->flags);115 server->service_id = call->service_id;116 }117 }118 119 rtt_us = rxrpc_kernel_get_srtt(addr->peer);120 if (rtt_us < server->probe.rtt) {121 server->probe.rtt = rtt_us;122 server->rtt = rtt_us;123 alist->preferred = index;124 }125 126 smp_wmb(); /* Set rtt before responded. */127 server->probe.flags |= AFS_VLSERVER_PROBE_RESPONDED;128 set_bit(AFS_VLSERVER_FL_PROBED, &server->flags);129 set_bit(AFS_VLSERVER_FL_RESPONDING, &server->flags);130 have_result = true;131out:132 spin_unlock(&server->probe_lock);133 134 trace_afs_vl_probe(server, false, alist, index, call->error, call->abort_code, rtt_us);135 _debug("probe [%u][%u] %pISpc rtt=%d ret=%d",136 server_index, index, rxrpc_kernel_remote_addr(addr->peer),137 rtt_us, ret);138 139 afs_done_one_vl_probe(server, have_result);140}141 142/*143 * Probe all of a vlserver's addresses to find out the best route and to144 * query its capabilities.145 */146static bool afs_do_probe_vlserver(struct afs_net *net,147 struct afs_vlserver *server,148 struct key *key,149 unsigned int server_index,150 struct afs_error *_e)151{152 struct afs_addr_list *alist;153 struct afs_call *call;154 unsigned long unprobed;155 unsigned int index, i;156 bool in_progress = false;157 int best_prio;158 159 _enter("%s", server->name);160 161 read_lock(&server->lock);162 alist = rcu_dereference_protected(server->addresses,163 lockdep_is_held(&server->lock));164 afs_get_addrlist(alist, afs_alist_trace_get_vlprobe);165 read_unlock(&server->lock);166 167 atomic_set(&server->probe_outstanding, alist->nr_addrs);168 memset(&server->probe, 0, sizeof(server->probe));169 server->probe.rtt = UINT_MAX;170 171 unprobed = (1UL << alist->nr_addrs) - 1;172 while (unprobed) {173 best_prio = -1;174 index = 0;175 for (i = 0; i < alist->nr_addrs; i++) {176 if (test_bit(i, &unprobed) &&177 alist->addrs[i].prio > best_prio) {178 index = i;179 best_prio = alist->addrs[i].prio;180 }181 }182 __clear_bit(index, &unprobed);183 184 trace_afs_vl_probe(server, true, alist, index, 0, 0, 0);185 call = afs_vl_get_capabilities(net, alist, index, key, server,186 server_index);187 if (!IS_ERR(call)) {188 afs_prioritise_error(_e, call->error, call->abort_code);189 afs_put_call(call);190 in_progress = true;191 } else {192 afs_prioritise_error(_e, PTR_ERR(call), 0);193 afs_done_one_vl_probe(server, false);194 }195 }196 197 afs_put_addrlist(alist, afs_alist_trace_put_vlprobe);198 return in_progress;199}200 201/*202 * Send off probes to all unprobed servers.203 */204int afs_send_vl_probes(struct afs_net *net, struct key *key,205 struct afs_vlserver_list *vllist)206{207 struct afs_vlserver *server;208 struct afs_error e = {};209 bool in_progress = false;210 int i;211 212 for (i = 0; i < vllist->nr_servers; i++) {213 server = vllist->servers[i].server;214 if (test_bit(AFS_VLSERVER_FL_PROBED, &server->flags))215 continue;216 217 if (!test_and_set_bit_lock(AFS_VLSERVER_FL_PROBING, &server->flags) &&218 afs_do_probe_vlserver(net, server, key, i, &e))219 in_progress = true;220 }221 222 return in_progress ? 0 : e.error;223}224 225/*226 * Wait for the first as-yet untried server to respond.227 */228int afs_wait_for_vl_probes(struct afs_vlserver_list *vllist,229 unsigned long untried)230{231 struct wait_queue_entry *waits;232 struct afs_vlserver *server;233 unsigned int rtt = UINT_MAX, rtt_s;234 bool have_responders = false;235 int pref = -1, i;236 237 _enter("%u,%lx", vllist->nr_servers, untried);238 239 /* Only wait for servers that have a probe outstanding. */240 for (i = 0; i < vllist->nr_servers; i++) {241 if (test_bit(i, &untried)) {242 server = vllist->servers[i].server;243 if (!test_bit(AFS_VLSERVER_FL_PROBING, &server->flags))244 __clear_bit(i, &untried);245 if (server->probe.flags & AFS_VLSERVER_PROBE_RESPONDED)246 have_responders = true;247 }248 }249 if (have_responders || !untried)250 return 0;251 252 waits = kmalloc(array_size(vllist->nr_servers, sizeof(*waits)), GFP_KERNEL);253 if (!waits)254 return -ENOMEM;255 256 for (i = 0; i < vllist->nr_servers; i++) {257 if (test_bit(i, &untried)) {258 server = vllist->servers[i].server;259 init_waitqueue_entry(&waits[i], current);260 add_wait_queue(&server->probe_wq, &waits[i]);261 }262 }263 264 for (;;) {265 bool still_probing = false;266 267 set_current_state(TASK_INTERRUPTIBLE);268 for (i = 0; i < vllist->nr_servers; i++) {269 if (test_bit(i, &untried)) {270 server = vllist->servers[i].server;271 if (server->probe.flags & AFS_VLSERVER_PROBE_RESPONDED)272 goto stop;273 if (test_bit(AFS_VLSERVER_FL_PROBING, &server->flags))274 still_probing = true;275 }276 }277 278 if (!still_probing || signal_pending(current))279 goto stop;280 schedule();281 }282 283stop:284 set_current_state(TASK_RUNNING);285 286 for (i = 0; i < vllist->nr_servers; i++) {287 if (test_bit(i, &untried)) {288 server = vllist->servers[i].server;289 rtt_s = READ_ONCE(server->rtt);290 if (test_bit(AFS_VLSERVER_FL_RESPONDING, &server->flags) &&291 rtt_s < rtt) {292 pref = i;293 rtt = rtt_s;294 }295 296 remove_wait_queue(&server->probe_wq, &waits[i]);297 }298 }299 300 kfree(waits);301 302 if (pref == -1 && signal_pending(current))303 return -ERESTARTSYS;304 305 if (pref >= 0)306 vllist->preferred = pref;307 308 _leave(" = 0 [%u]", pref);309 return 0;310}311