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
afs_get_endpoint_state(struct afs_endpoint_state * estate,enum afs_estate_trace where)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
afs_endpoint_state_rcu(struct rcu_head * rcu)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
afs_put_endpoint_state(struct afs_endpoint_state * estate,enum afs_estate_trace where)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 */
afs_schedule_fs_probe(struct afs_net * net,struct afs_server * server,bool fast)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 */
afs_finished_fs_probe(struct afs_net * net,struct afs_server * server,struct afs_endpoint_state * estate)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 */
afs_done_one_fs_probe(struct afs_net * net,struct afs_server * server,struct afs_endpoint_state * estate)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 */
afs_fs_probe_not_done(struct afs_net * net,struct afs_server * server,struct afs_endpoint_state * estate,int index)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 */
afs_fileserver_probe_result(struct afs_call * call)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 */
afs_fs_probe_fileserver(struct afs_net * net,struct afs_server * server,struct afs_addr_list * new_alist,struct key * key)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 */
afs_wait_for_fs_probes(struct afs_operation * op,struct afs_server_state * states,bool intr)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 */
afs_fs_probe_timer(struct timer_list * timer)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 */
afs_dispatch_fs_probe(struct afs_net * net,struct afs_server * server)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 */
afs_probe_fileserver(struct afs_net * net,struct afs_server * server)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 */
afs_fs_probe_dispatcher(struct work_struct * work)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 */
afs_wait_for_one_fs_probe(struct afs_server * server,struct afs_endpoint_state * estate,unsigned long exclude,bool is_intr)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 */
afs_fs_probe_cleanup(struct afs_net * net)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