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 15 static unsigned int afs_fs_probe_fast_poll_interval = 30 * HZ; 16 static unsigned int afs_fs_probe_slow_poll_interval = 5 * 60 * HZ; 17 18 struct 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 30 static 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 40 void 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 */ 58 static 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 */ 77 static 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 */ 99 static 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 */ 114 static 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 */ 138 void 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 } 190 191 responded: 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); 222 out: 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 */ 238 int 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 *old_alist = NULL, *alist; 243 unsigned long unprobed; 244 245 _enter("%pU", &server->uuid); 246 247 estate = kzalloc_obj(*estate); 248 if (!estate) 249 return -ENOMEM; 250 251 refcount_set(&estate->ref, 2); 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 if (old) { 260 estate->responsive_set = old->responsive_set; 261 old_alist = old->addresses; 262 if (!new_alist) 263 new_alist = old->addresses; 264 } 265 266 if (old_alist != new_alist) 267 afs_set_peer_appdata(server, old_alist, new_alist); 268 269 estate->addresses = afs_get_addrlist(new_alist, afs_alist_trace_get_estate); 270 alist = estate->addresses; 271 estate->probe_seq = ++server->probe_counter; 272 atomic_set(&estate->nr_probing, alist->nr_addrs); 273 274 if (new_alist) 275 server->addr_version = new_alist->version; 276 rcu_assign_pointer(server->endpoint_state, estate); 277 write_unlock(&server->fs_lock); 278 if (old) 279 set_bit(AFS_ESTATE_SUPERSEDED, &old->flags); 280 281 trace_afs_estate(estate->server_id, estate->probe_seq, refcount_read(&estate->ref), 282 afs_estate_trace_alloc_probe); 283 284 afs_get_address_preferences(net, new_alist); 285 286 server->probed_at = jiffies; 287 unprobed = (1UL << alist->nr_addrs) - 1; 288 while (unprobed) { 289 unsigned int index = 0, i; 290 int best_prio = -1; 291 292 for (i = 0; i < alist->nr_addrs; i++) { 293 if (test_bit(i, &unprobed) && 294 alist->addrs[i].prio > best_prio) { 295 index = i; 296 best_prio = alist->addrs[i].prio; 297 } 298 } 299 __clear_bit(index, &unprobed); 300 301 trace_afs_fs_probe(server, true, estate, index, 0, 0, 0); 302 if (!afs_fs_get_capabilities(net, server, estate, index, key)) 303 afs_fs_probe_not_done(net, server, estate, index); 304 } 305 306 afs_put_endpoint_state(old, afs_estate_trace_put_probe); 307 afs_put_endpoint_state(estate, afs_estate_trace_put_probe); 308 return 0; 309 } 310 311 /* 312 * Wait for the first as-yet untried fileserver to respond, for the probe state 313 * to be superseded or for all probes to finish. 314 */ 315 int afs_wait_for_fs_probes(struct afs_operation *op, struct afs_server_state *states, bool intr) 316 { 317 struct afs_endpoint_state *estate; 318 struct afs_server_list *slist = op->server_list; 319 bool still_probing = true; 320 int ret = 0, i; 321 322 _enter("%u", slist->nr_servers); 323 324 for (i = 0; i < slist->nr_servers; i++) { 325 estate = states[i].endpoint_state; 326 if (test_bit(AFS_ESTATE_SUPERSEDED, &estate->flags)) 327 return 2; 328 if (atomic_read(&estate->nr_probing)) 329 still_probing = true; 330 if (estate->responsive_set & states[i].untried_addrs) 331 return 1; 332 } 333 if (!still_probing) 334 return 0; 335 336 for (i = 0; i < slist->nr_servers; i++) 337 add_wait_queue(&slist->servers[i].server->probe_wq, &states[i].probe_waiter); 338 339 for (;;) { 340 still_probing = false; 341 342 set_current_state(intr ? TASK_INTERRUPTIBLE : TASK_UNINTERRUPTIBLE); 343 for (i = 0; i < slist->nr_servers; i++) { 344 estate = states[i].endpoint_state; 345 if (test_bit(AFS_ESTATE_SUPERSEDED, &estate->flags)) { 346 ret = 2; 347 goto stop; 348 } 349 if (atomic_read(&estate->nr_probing)) 350 still_probing = true; 351 if (estate->responsive_set & states[i].untried_addrs) { 352 ret = 1; 353 goto stop; 354 } 355 } 356 357 if (!still_probing || signal_pending(current)) 358 goto stop; 359 schedule(); 360 } 361 362 stop: 363 set_current_state(TASK_RUNNING); 364 365 for (i = 0; i < slist->nr_servers; i++) 366 remove_wait_queue(&slist->servers[i].server->probe_wq, &states[i].probe_waiter); 367 368 if (!ret && signal_pending(current)) 369 ret = -ERESTARTSYS; 370 return ret; 371 } 372 373 /* 374 * Probe timer. We have an increment on fs_outstanding that we need to pass 375 * along to the work item. 376 */ 377 void afs_fs_probe_timer(struct timer_list *timer) 378 { 379 struct afs_net *net = container_of(timer, struct afs_net, fs_probe_timer); 380 381 if (!net->live || !queue_work(afs_wq, &net->fs_prober)) 382 afs_dec_servers_outstanding(net); 383 } 384 385 /* 386 * Dispatch a probe to a server. 387 */ 388 static void afs_dispatch_fs_probe(struct afs_net *net, struct afs_server *server) 389 __releases(&net->fs_lock) 390 { 391 struct key *key = NULL; 392 393 /* We remove it from the queues here - it will be added back to 394 * one of the queues on the completion of the probe. 395 */ 396 list_del_init(&server->probe_link); 397 398 afs_get_server(server, afs_server_trace_get_probe); 399 write_sequnlock(&net->fs_lock); 400 401 afs_fs_probe_fileserver(net, server, NULL, key); 402 afs_put_server(net, server, afs_server_trace_put_probe); 403 } 404 405 /* 406 * Probe a server immediately without waiting for its due time to come 407 * round. This is used when all of the addresses have been tried. 408 */ 409 void afs_probe_fileserver(struct afs_net *net, struct afs_server *server) 410 { 411 write_seqlock(&net->fs_lock); 412 if (!list_empty(&server->probe_link)) 413 return afs_dispatch_fs_probe(net, server); 414 write_sequnlock(&net->fs_lock); 415 } 416 417 /* 418 * Probe dispatcher to regularly dispatch probes to keep NAT alive. 419 */ 420 void afs_fs_probe_dispatcher(struct work_struct *work) 421 { 422 struct afs_net *net = container_of(work, struct afs_net, fs_prober); 423 struct afs_server *fast, *slow, *server; 424 unsigned long nowj, timer_at, poll_at; 425 bool first_pass = true, set_timer = false; 426 427 if (!net->live) { 428 afs_dec_servers_outstanding(net); 429 return; 430 } 431 432 _enter(""); 433 434 if (list_empty(&net->fs_probe_fast) && list_empty(&net->fs_probe_slow)) { 435 afs_dec_servers_outstanding(net); 436 _leave(" [none]"); 437 return; 438 } 439 440 again: 441 write_seqlock(&net->fs_lock); 442 443 fast = slow = server = NULL; 444 nowj = jiffies; 445 timer_at = nowj + MAX_JIFFY_OFFSET; 446 447 if (!list_empty(&net->fs_probe_fast)) { 448 fast = list_first_entry(&net->fs_probe_fast, struct afs_server, probe_link); 449 poll_at = fast->probed_at + afs_fs_probe_fast_poll_interval; 450 if (time_before(nowj, poll_at)) { 451 timer_at = poll_at; 452 set_timer = true; 453 fast = NULL; 454 } 455 } 456 457 if (!list_empty(&net->fs_probe_slow)) { 458 slow = list_first_entry(&net->fs_probe_slow, struct afs_server, probe_link); 459 poll_at = slow->probed_at + afs_fs_probe_slow_poll_interval; 460 if (time_before(nowj, poll_at)) { 461 if (time_before(poll_at, timer_at)) 462 timer_at = poll_at; 463 set_timer = true; 464 slow = NULL; 465 } 466 } 467 468 server = fast ?: slow; 469 if (server) 470 _debug("probe %pU", &server->uuid); 471 472 if (server && (first_pass || !need_resched())) { 473 afs_dispatch_fs_probe(net, server); 474 first_pass = false; 475 goto again; 476 } 477 478 write_sequnlock(&net->fs_lock); 479 480 if (server) { 481 if (!queue_work(afs_wq, &net->fs_prober)) 482 afs_dec_servers_outstanding(net); 483 _leave(" [requeue]"); 484 } else if (set_timer) { 485 if (timer_reduce(&net->fs_probe_timer, timer_at)) 486 afs_dec_servers_outstanding(net); 487 _leave(" [timer]"); 488 } else { 489 afs_dec_servers_outstanding(net); 490 _leave(" [quiesce]"); 491 } 492 } 493 494 /* 495 * Wait for a probe on a particular fileserver to complete for 2s. 496 */ 497 int afs_wait_for_one_fs_probe(struct afs_server *server, struct afs_endpoint_state *estate, 498 unsigned long exclude, bool is_intr) 499 { 500 struct wait_queue_entry wait; 501 unsigned long timo = 2 * HZ; 502 503 if (atomic_read(&estate->nr_probing) == 0) 504 goto dont_wait; 505 506 init_wait_entry(&wait, 0); 507 for (;;) { 508 prepare_to_wait_event(&server->probe_wq, &wait, 509 is_intr ? TASK_INTERRUPTIBLE : TASK_UNINTERRUPTIBLE); 510 if (timo == 0 || 511 test_bit(AFS_ESTATE_SUPERSEDED, &estate->flags) || 512 (estate->responsive_set & ~exclude) || 513 atomic_read(&estate->nr_probing) == 0 || 514 (is_intr && signal_pending(current))) 515 break; 516 timo = schedule_timeout(timo); 517 } 518 519 finish_wait(&server->probe_wq, &wait); 520 521 dont_wait: 522 if (test_bit(AFS_ESTATE_SUPERSEDED, &estate->flags)) 523 return 0; 524 if (estate->responsive_set & ~exclude) 525 return 1; 526 if (is_intr && signal_pending(current)) 527 return -ERESTARTSYS; 528 if (timo == 0) 529 return -ETIME; 530 return -EDESTADDRREQ; 531 } 532 533 /* 534 * Clean up the probing when the namespace is killed off. 535 */ 536 void afs_fs_probe_cleanup(struct afs_net *net) 537 { 538 if (timer_delete_sync(&net->fs_probe_timer)) 539 afs_dec_servers_outstanding(net); 540 } 541