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0; 308 } 309 310 /* 311 * Wait for the first as-yet untried fileserver to respond, for the probe state 312 * to be superseded or for all probes to finish. 313 */ 314 int afs_wait_for_fs_probes(struct afs_operation *op, struct afs_server_state *states, bool intr) 315 { 316 struct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