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 void 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 */
afs_wait_for_fs_probes(struct afs_operation * op,struct afs_server_state * states,bool intr)302 int 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
349 stop:
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 */
afs_fs_probe_timer(struct timer_list * timer)364 void 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 */
afs_dispatch_fs_probe(struct afs_net * net,struct afs_server * server)375 static 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 */
afs_probe_fileserver(struct afs_net * net,struct afs_server * server)396 void 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 */
afs_fs_probe_dispatcher(struct work_struct * work)407 void 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
427 again:
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 */
afs_wait_for_one_fs_probe(struct afs_server * server,struct afs_endpoint_state * estate,unsigned long exclude,bool is_intr)484 int 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
508 dont_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 */
afs_fs_probe_cleanup(struct afs_net * net)523 void 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