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1// SPDX-License-Identifier: GPL-2.0-or-later2/* AFS fileserver probing3 *4 * Copyright (C) 2018, 2020 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_afs.h"13#include "protocol_yfs.h"14 15static unsigned int afs_fs_probe_fast_poll_interval = 30 * HZ;16static unsigned int afs_fs_probe_slow_poll_interval = 5 * 60 * HZ;17 18struct afs_endpoint_state *afs_get_endpoint_state(struct afs_endpoint_state *estate,19 enum afs_estate_trace where)20{21 if (estate) {22 int r;23 24 __refcount_inc(&estate->ref, &r);25 trace_afs_estate(estate->server_id, estate->probe_seq, r, where);26 }27 return estate;28}29 30static void afs_endpoint_state_rcu(struct rcu_head *rcu)31{32 struct afs_endpoint_state *estate = container_of(rcu, struct afs_endpoint_state, rcu);33 34 trace_afs_estate(estate->server_id, estate->probe_seq, refcount_read(&estate->ref),35 afs_estate_trace_free);36 afs_put_addrlist(estate->addresses, afs_alist_trace_put_estate);37 kfree(estate);38}39 40void afs_put_endpoint_state(struct afs_endpoint_state *estate, enum afs_estate_trace where)41{42 if (estate) {43 unsigned int server_id = estate->server_id, probe_seq = estate->probe_seq;44 bool dead;45 int r;46 47 dead = __refcount_dec_and_test(&estate->ref, &r);48 trace_afs_estate(server_id, probe_seq, r, where);49 if (dead)50 call_rcu(&estate->rcu, afs_endpoint_state_rcu);51 }52}53 54/*55 * Start the probe polling timer. We have to supply it with an inc on the56 * outstanding server count.57 */58static void afs_schedule_fs_probe(struct afs_net *net,59 struct afs_server *server, bool fast)60{61 unsigned long atj;62 63 if (!net->live)64 return;65 66 atj = server->probed_at;67 atj += fast ? afs_fs_probe_fast_poll_interval : afs_fs_probe_slow_poll_interval;68 69 afs_inc_servers_outstanding(net);70 if (timer_reduce(&net->fs_probe_timer, atj))71 afs_dec_servers_outstanding(net);72}73 74/*75 * Handle the completion of a set of probes.76 */77static void afs_finished_fs_probe(struct afs_net *net, struct afs_server *server,78 struct afs_endpoint_state *estate)79{80 bool responded = test_bit(AFS_ESTATE_RESPONDED, &estate->flags);81 82 write_seqlock(&net->fs_lock);83 if (responded) {84 list_add_tail(&server->probe_link, &net->fs_probe_slow);85 } else {86 server->rtt = UINT_MAX;87 clear_bit(AFS_SERVER_FL_RESPONDING, &server->flags);88 list_add_tail(&server->probe_link, &net->fs_probe_fast);89 }90 91 write_sequnlock(&net->fs_lock);92 93 afs_schedule_fs_probe(net, server, !responded);94}95 96/*97 * Handle the completion of a probe.98 */99static void afs_done_one_fs_probe(struct afs_net *net, struct afs_server *server,100 struct afs_endpoint_state *estate)101{102 _enter("");103 104 if (atomic_dec_and_test(&estate->nr_probing))105 afs_finished_fs_probe(net, server, estate);106 107 wake_up_all(&server->probe_wq);108}109 110/*111 * Handle inability to send a probe due to ENOMEM when trying to allocate a112 * call struct.113 */114static void afs_fs_probe_not_done(struct afs_net *net,115 struct afs_server *server,116 struct afs_endpoint_state *estate,117 int index)118{119 _enter("");120 121 trace_afs_io_error(0, -ENOMEM, afs_io_error_fs_probe_fail);122 spin_lock(&server->probe_lock);123 124 set_bit(AFS_ESTATE_LOCAL_FAILURE, &estate->flags);125 if (estate->error == 0)126 estate->error = -ENOMEM;127 128 set_bit(index, &estate->failed_set);129 130 spin_unlock(&server->probe_lock);131 return afs_done_one_fs_probe(net, server, estate);132}133 134/*135 * Process the result of probing a fileserver. This is called after successful136 * or failed delivery of an FS.GetCapabilities operation.137 */138void afs_fileserver_probe_result(struct afs_call *call)139{140 struct afs_endpoint_state *estate = call->probe;141 struct afs_addr_list *alist = estate->addresses;142 struct afs_address *addr = &alist->addrs[call->probe_index];143 struct afs_server *server = call->server;144 unsigned int index = call->probe_index;145 unsigned int rtt_us = -1, cap0;146 int ret = call->error;147 148 _enter("%pU,%u", &server->uuid, index);149 150 WRITE_ONCE(addr->last_error, ret);151 152 spin_lock(&server->probe_lock);153 154 switch (ret) {155 case 0:156 estate->error = 0;157 goto responded;158 case -ECONNABORTED:159 if (!test_bit(AFS_ESTATE_RESPONDED, &estate->flags)) {160 estate->abort_code = call->abort_code;161 estate->error = ret;162 }163 goto responded;164 case -ENOMEM:165 case -ENONET:166 clear_bit(index, &estate->responsive_set);167 set_bit(AFS_ESTATE_LOCAL_FAILURE, &estate->flags);168 trace_afs_io_error(call->debug_id, ret, afs_io_error_fs_probe_fail);169 goto out;170 case -ECONNRESET: /* Responded, but call expired. */171 case -ERFKILL:172 case -EADDRNOTAVAIL:173 case -ENETUNREACH:174 case -EHOSTUNREACH:175 case -EHOSTDOWN:176 case -ECONNREFUSED:177 case -ETIMEDOUT:178 case -ETIME:179 default:180 clear_bit(index, &estate->responsive_set);181 set_bit(index, &estate->failed_set);182 if (!test_bit(AFS_ESTATE_RESPONDED, &estate->flags) &&183 (estate->error == 0 ||184 estate->error == -ETIMEDOUT ||185 estate->error == -ETIME))186 estate->error = ret;187 trace_afs_io_error(call->debug_id, ret, afs_io_error_fs_probe_fail);188 goto out;189 }190 191responded:192 clear_bit(index, &estate->failed_set);193 194 if (call->service_id == YFS_FS_SERVICE) {195 set_bit(AFS_ESTATE_IS_YFS, &estate->flags);196 set_bit(AFS_SERVER_FL_IS_YFS, &server->flags);197 server->service_id = call->service_id;198 } else {199 set_bit(AFS_ESTATE_NOT_YFS, &estate->flags);200 if (!test_bit(AFS_ESTATE_IS_YFS, &estate->flags)) {201 clear_bit(AFS_SERVER_FL_IS_YFS, &server->flags);202 server->service_id = call->service_id;203 }204 cap0 = ntohl(call->tmp);205 if (cap0 & AFS3_VICED_CAPABILITY_64BITFILES)206 set_bit(AFS_SERVER_FL_HAS_FS64, &server->flags);207 else208 clear_bit(AFS_SERVER_FL_HAS_FS64, &server->flags);209 }210 211 rtt_us = rxrpc_kernel_get_srtt(addr->peer);212 if (rtt_us < estate->rtt) {213 estate->rtt = rtt_us;214 server->rtt = rtt_us;215 alist->preferred = index;216 }217 218 smp_wmb(); /* Set rtt before responded. */219 set_bit(AFS_ESTATE_RESPONDED, &estate->flags);220 set_bit(index, &estate->responsive_set);221 set_bit(AFS_SERVER_FL_RESPONDING, &server->flags);222out:223 spin_unlock(&server->probe_lock);224 225 trace_afs_fs_probe(server, false, estate, index, call->error, call->abort_code, rtt_us);226 _debug("probe[%x] %pU [%u] %pISpc rtt=%d ret=%d",227 estate->probe_seq, &server->uuid, index,228 rxrpc_kernel_remote_addr(alist->addrs[index].peer),229 rtt_us, ret);230 231 return afs_done_one_fs_probe(call->net, server, estate);232}233 234/*235 * Probe all of a fileserver's addresses to find out the best route and to236 * query its capabilities.237 */238void afs_fs_probe_fileserver(struct afs_net *net, struct afs_server *server,239 struct afs_addr_list *new_alist, struct key *key)240{241 struct afs_endpoint_state *estate, *old;242 struct afs_addr_list *alist;243 unsigned long unprobed;244 245 _enter("%pU", &server->uuid);246 247 estate = kzalloc(sizeof(*estate), GFP_KERNEL);248 if (!estate)249 return;250 251 refcount_set(&estate->ref, 1);252 estate->server_id = server->debug_id;253 estate->rtt = UINT_MAX;254 255 write_lock(&server->fs_lock);256 257 old = rcu_dereference_protected(server->endpoint_state,258 lockdep_is_held(&server->fs_lock));259 estate->responsive_set = old->responsive_set;260 estate->addresses = afs_get_addrlist(new_alist ?: old->addresses,261 afs_alist_trace_get_estate);262 alist = estate->addresses;263 estate->probe_seq = ++server->probe_counter;264 atomic_set(&estate->nr_probing, alist->nr_addrs);265 266 rcu_assign_pointer(server->endpoint_state, estate);267 set_bit(AFS_ESTATE_SUPERSEDED, &old->flags);268 write_unlock(&server->fs_lock);269 270 trace_afs_estate(estate->server_id, estate->probe_seq, refcount_read(&estate->ref),271 afs_estate_trace_alloc_probe);272 273 afs_get_address_preferences(net, alist);274 275 server->probed_at = jiffies;276 unprobed = (1UL << alist->nr_addrs) - 1;277 while (unprobed) {278 unsigned int index = 0, i;279 int best_prio = -1;280 281 for (i = 0; i < alist->nr_addrs; i++) {282 if (test_bit(i, &unprobed) &&283 alist->addrs[i].prio > best_prio) {284 index = i;285 best_prio = alist->addrs[i].prio;286 }287 }288 __clear_bit(index, &unprobed);289 290 trace_afs_fs_probe(server, true, estate, index, 0, 0, 0);291 if (!afs_fs_get_capabilities(net, server, estate, index, key))292 afs_fs_probe_not_done(net, server, estate, index);293 }294 295 afs_put_endpoint_state(old, afs_estate_trace_put_probe);296}297 298/*299 * Wait for the first as-yet untried fileserver to respond, for the probe state300 * to be superseded or for all probes to finish.301 */302int afs_wait_for_fs_probes(struct afs_operation *op, struct afs_server_state *states, bool intr)303{304 struct afs_endpoint_state *estate;305 struct afs_server_list *slist = op->server_list;306 bool still_probing = true;307 int ret = 0, i;308 309 _enter("%u", slist->nr_servers);310 311 for (i = 0; i < slist->nr_servers; i++) {312 estate = states[i].endpoint_state;313 if (test_bit(AFS_ESTATE_SUPERSEDED, &estate->flags))314 return 2;315 if (atomic_read(&estate->nr_probing))316 still_probing = true;317 if (estate->responsive_set & states[i].untried_addrs)318 return 1;319 }320 if (!still_probing)321 return 0;322 323 for (i = 0; i < slist->nr_servers; i++)324 add_wait_queue(&slist->servers[i].server->probe_wq, &states[i].probe_waiter);325 326 for (;;) {327 still_probing = false;328 329 set_current_state(intr ? TASK_INTERRUPTIBLE : TASK_UNINTERRUPTIBLE);330 for (i = 0; i < slist->nr_servers; i++) {331 estate = states[i].endpoint_state;332 if (test_bit(AFS_ESTATE_SUPERSEDED, &estate->flags)) {333 ret = 2;334 goto stop;335 }336 if (atomic_read(&estate->nr_probing))337 still_probing = true;338 if (estate->responsive_set & states[i].untried_addrs) {339 ret = 1;340 goto stop;341 }342 }343 344 if (!still_probing || signal_pending(current))345 goto stop;346 schedule();347 }348 349stop:350 set_current_state(TASK_RUNNING);351 352 for (i = 0; i < slist->nr_servers; i++)353 remove_wait_queue(&slist->servers[i].server->probe_wq, &states[i].probe_waiter);354 355 if (!ret && signal_pending(current))356 ret = -ERESTARTSYS;357 return ret;358}359 360/*361 * Probe timer. We have an increment on fs_outstanding that we need to pass362 * along to the work item.363 */364void afs_fs_probe_timer(struct timer_list *timer)365{366 struct afs_net *net = container_of(timer, struct afs_net, fs_probe_timer);367 368 if (!net->live || !queue_work(afs_wq, &net->fs_prober))369 afs_dec_servers_outstanding(net);370}371 372/*373 * Dispatch a probe to a server.374 */375static void afs_dispatch_fs_probe(struct afs_net *net, struct afs_server *server)376 __releases(&net->fs_lock)377{378 struct key *key = NULL;379 380 /* We remove it from the queues here - it will be added back to381 * one of the queues on the completion of the probe.382 */383 list_del_init(&server->probe_link);384 385 afs_get_server(server, afs_server_trace_get_probe);386 write_sequnlock(&net->fs_lock);387 388 afs_fs_probe_fileserver(net, server, NULL, key);389 afs_put_server(net, server, afs_server_trace_put_probe);390}391 392/*393 * Probe a server immediately without waiting for its due time to come394 * round. This is used when all of the addresses have been tried.395 */396void afs_probe_fileserver(struct afs_net *net, struct afs_server *server)397{398 write_seqlock(&net->fs_lock);399 if (!list_empty(&server->probe_link))400 return afs_dispatch_fs_probe(net, server);401 write_sequnlock(&net->fs_lock);402}403 404/*405 * Probe dispatcher to regularly dispatch probes to keep NAT alive.406 */407void afs_fs_probe_dispatcher(struct work_struct *work)408{409 struct afs_net *net = container_of(work, struct afs_net, fs_prober);410 struct afs_server *fast, *slow, *server;411 unsigned long nowj, timer_at, poll_at;412 bool first_pass = true, set_timer = false;413 414 if (!net->live) {415 afs_dec_servers_outstanding(net);416 return;417 }418 419 _enter("");420 421 if (list_empty(&net->fs_probe_fast) && list_empty(&net->fs_probe_slow)) {422 afs_dec_servers_outstanding(net);423 _leave(" [none]");424 return;425 }426 427again:428 write_seqlock(&net->fs_lock);429 430 fast = slow = server = NULL;431 nowj = jiffies;432 timer_at = nowj + MAX_JIFFY_OFFSET;433 434 if (!list_empty(&net->fs_probe_fast)) {435 fast = list_first_entry(&net->fs_probe_fast, struct afs_server, probe_link);436 poll_at = fast->probed_at + afs_fs_probe_fast_poll_interval;437 if (time_before(nowj, poll_at)) {438 timer_at = poll_at;439 set_timer = true;440 fast = NULL;441 }442 }443 444 if (!list_empty(&net->fs_probe_slow)) {445 slow = list_first_entry(&net->fs_probe_slow, struct afs_server, probe_link);446 poll_at = slow->probed_at + afs_fs_probe_slow_poll_interval;447 if (time_before(nowj, poll_at)) {448 if (time_before(poll_at, timer_at))449 timer_at = poll_at;450 set_timer = true;451 slow = NULL;452 }453 }454 455 server = fast ?: slow;456 if (server)457 _debug("probe %pU", &server->uuid);458 459 if (server && (first_pass || !need_resched())) {460 afs_dispatch_fs_probe(net, server);461 first_pass = false;462 goto again;463 }464 465 write_sequnlock(&net->fs_lock);466 467 if (server) {468 if (!queue_work(afs_wq, &net->fs_prober))469 afs_dec_servers_outstanding(net);470 _leave(" [requeue]");471 } else if (set_timer) {472 if (timer_reduce(&net->fs_probe_timer, timer_at))473 afs_dec_servers_outstanding(net);474 _leave(" [timer]");475 } else {476 afs_dec_servers_outstanding(net);477 _leave(" [quiesce]");478 }479}480 481/*482 * Wait for a probe on a particular fileserver to complete for 2s.483 */484int afs_wait_for_one_fs_probe(struct afs_server *server, struct afs_endpoint_state *estate,485 unsigned long exclude, bool is_intr)486{487 struct wait_queue_entry wait;488 unsigned long timo = 2 * HZ;489 490 if (atomic_read(&estate->nr_probing) == 0)491 goto dont_wait;492 493 init_wait_entry(&wait, 0);494 for (;;) {495 prepare_to_wait_event(&server->probe_wq, &wait,496 is_intr ? TASK_INTERRUPTIBLE : TASK_UNINTERRUPTIBLE);497 if (timo == 0 ||498 test_bit(AFS_ESTATE_SUPERSEDED, &estate->flags) ||499 (estate->responsive_set & ~exclude) ||500 atomic_read(&estate->nr_probing) == 0 ||501 (is_intr && signal_pending(current)))502 break;503 timo = schedule_timeout(timo);504 }505 506 finish_wait(&server->probe_wq, &wait);507 508dont_wait:509 if (test_bit(AFS_ESTATE_SUPERSEDED, &estate->flags))510 return 0;511 if (estate->responsive_set & ~exclude)512 return 1;513 if (is_intr && signal_pending(current))514 return -ERESTARTSYS;515 if (timo == 0)516 return -ETIME;517 return -EDESTADDRREQ;518}519 520/*521 * Clean up the probing when the namespace is killed off.522 */523void afs_fs_probe_cleanup(struct afs_net *net)524{525 if (del_timer_sync(&net->fs_probe_timer))526 afs_dec_servers_outstanding(net);527}528