1// SPDX-License-Identifier: GPL-2.0-or-later 2/* AFS fileserver probing 3 * 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 the 56 * 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 a 112 * 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 successful 136 * 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 else 208 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 to 236 * 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 state 300 * 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 pass 362 * 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 to 381 * 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 come 394 * 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 (estate->responsive_set & ~exclude) 510 return 1; 511 if (test_bit(AFS_ESTATE_SUPERSEDED, &estate->flags)) 512 return 0; 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