1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* AFS vlserver probing
3 *
4 * Copyright (C) 2018 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_yfs.h"
13
14
15 /*
16 * Handle the completion of a set of probes.
17 */
18 static void afs_finished_vl_probe(struct afs_vlserver *server)
19 {
20 if (!(server->probe.flags & AFS_VLSERVER_PROBE_RESPONDED)) {
21 server->rtt = UINT_MAX;
22 clear_bit(AFS_VLSERVER_FL_RESPONDING, &server->flags);
23 }
24
25 clear_bit_unlock(AFS_VLSERVER_FL_PROBING, &server->flags);
26 wake_up_bit(&server->flags, AFS_VLSERVER_FL_PROBING);
27 }
28
29 /*
30 * Handle the completion of a probe RPC call.
31 */
32 static void afs_done_one_vl_probe(struct afs_vlserver *server, bool wake_up)
33 {
34 if (atomic_dec_and_test(&server->probe_outstanding)) {
35 afs_finished_vl_probe(server);
36 wake_up = true;
37 }
38
39 if (wake_up)
40 wake_up_all(&server->probe_wq);
41 }
42
43 /*
44 * Process the result of probing a vlserver. This is called after successful
45 * or failed delivery of an VL.GetCapabilities operation.
46 */
47 void afs_vlserver_probe_result(struct afs_call *call)
48 {
49 struct afs_addr_list *alist = call->vl_probe;
50 struct afs_vlserver *server = call->vlserver;
51 struct afs_address *addr = &alist->addrs[call->probe_index];
52 unsigned int server_index = call->server_index;
53 unsigned int rtt_us = 0;
54 unsigned int index = call->probe_index;
55 bool have_result = false;
56 int ret = call->error;
57
58 _enter("%s,%u,%u,%d,%d", server->name, server_index, index, ret, call->abort_code);
59
60 spin_lock(&server->probe_lock);
61
62 switch (ret) {
63 case 0:
64 server->probe.error = 0;
65 goto responded;
66 case -ECONNABORTED:
67 if (!(server->probe.flags & AFS_VLSERVER_PROBE_RESPONDED)) {
68 server->probe.abort_code = call->abort_code;
69 server->probe.error = ret;
70 }
71 goto responded;
72 case -ENOMEM:
73 case -ENONET:
74 case -EKEYEXPIRED:
75 case -EKEYREVOKED:
76 case -EKEYREJECTED:
77 server->probe.flags |= AFS_VLSERVER_PROBE_LOCAL_FAILURE;
78 if (server->probe.error == 0)
79 server->probe.error = ret;
80 trace_afs_io_error(call->debug_id, ret, afs_io_error_vl_probe_fail);
81 goto out;
82 case -ECONNRESET: /* Responded, but call expired. */
83 case -ERFKILL:
84 case -EADDRNOTAVAIL:
85 case -ENETUNREACH:
86 case -EHOSTUNREACH:
87 case -EHOSTDOWN:
88 case -ECONNREFUSED:
89 case -ETIMEDOUT:
90 case -ETIME:
91 default:
92 clear_bit(index, &alist->responded);
93 set_bit(index, &alist->probe_failed);
94 if (!(server->probe.flags & AFS_VLSERVER_PROBE_RESPONDED) &&
95 (server->probe.error == 0 ||
96 server->probe.error == -ETIMEDOUT ||
97 server->probe.error == -ETIME))
98 server->probe.error = ret;
99 trace_afs_io_error(call->debug_id, ret, afs_io_error_vl_probe_fail);
100 goto out;
101 }
102
103 responded:
104 set_bit(index, &alist->responded);
105 clear_bit(index, &alist->probe_failed);
106
107 if (call->service_id == YFS_VL_SERVICE) {
108 server->probe.flags |= AFS_VLSERVER_PROBE_IS_YFS;
109 set_bit(AFS_VLSERVER_FL_IS_YFS, &server->flags);
110 server->service_id = call->service_id;
111 } else {
112 server->probe.flags |= AFS_VLSERVER_PROBE_NOT_YFS;
113 if (!(server->probe.flags & AFS_VLSERVER_PROBE_IS_YFS)) {
114 clear_bit(AFS_VLSERVER_FL_IS_YFS, &server->flags);
115 server->service_id = call->service_id;
116 }
117 }
118
119 rtt_us = rxrpc_kernel_get_srtt(addr->peer);
120 if (rtt_us < server->probe.rtt) {
121 server->probe.rtt = rtt_us;
122 server->rtt = rtt_us;
123 alist->preferred = index;
124 }
125
126 smp_wmb(); /* Set rtt before responded. */
127 server->probe.flags |= AFS_VLSERVER_PROBE_RESPONDED;
128 set_bit(AFS_VLSERVER_FL_PROBED, &server->flags);
129 set_bit(AFS_VLSERVER_FL_RESPONDING, &server->flags);
130 have_result = true;
131 out:
132 spin_unlock(&server->probe_lock);
133
134 trace_afs_vl_probe(server, false, alist, index, call->error, call->abort_code, rtt_us);
135 _debug("probe [%u][%u] %pISpc rtt=%d ret=%d",
136 server_index, index, rxrpc_kernel_remote_addr(addr->peer),
137 rtt_us, ret);
138
139 afs_done_one_vl_probe(server, have_result);
140 }
141
142 /*
143 * Probe all of a vlserver's addresses to find out the best route and to
144 * query its capabilities.
145 */
146 static bool afs_do_probe_vlserver(struct afs_net *net,
147 struct afs_vlserver *server,
148 struct key *key,
149 unsigned int server_index,
150 struct afs_error *_e)
151 {
152 struct afs_addr_list *alist;
153 struct afs_call *call;
154 unsigned long unprobed;
155 unsigned int index, i;
156 bool in_progress = false;
157 int best_prio;
158
159 _enter("%s", server->name);
160
161 read_lock(&server->lock);
162 alist = rcu_dereference_protected(server->addresses,
163 lockdep_is_held(&server->lock));
164 afs_get_addrlist(alist, afs_alist_trace_get_vlprobe);
165 read_unlock(&server->lock);
166
167 atomic_set(&server->probe_outstanding, alist->nr_addrs);
168 memset(&server->probe, 0, sizeof(server->probe));
169 server->probe.rtt = UINT_MAX;
170
171 unprobed = (1UL << alist->nr_addrs) - 1;
172 while (unprobed) {
173 best_prio = -1;
174 index = 0;
175 for (i = 0; i < alist->nr_addrs; i++) {
176 if (test_bit(i, &unprobed) &&
177 alist->addrs[i].prio > best_prio) {
178 index = i;
179 best_prio = alist->addrs[i].prio;
180 }
181 }
182 __clear_bit(index, &unprobed);
183
184 trace_afs_vl_probe(server, true, alist, index, 0, 0, 0);
185 call = afs_vl_get_capabilities(net, alist, index, key, server,
186 server_index);
187 if (!IS_ERR(call)) {
188 afs_prioritise_error(_e, call->error, call->abort_code);
189 afs_put_call(call);
190 in_progress = true;
191 } else {
192 afs_prioritise_error(_e, PTR_ERR(call), 0);
193 afs_done_one_vl_probe(server, false);
194 }
195 }
196
197 afs_put_addrlist(alist, afs_alist_trace_put_vlprobe);
198 return in_progress;
199 }
200
201 /*
202 * Send off probes to all unprobed servers.
203 */
204 int afs_send_vl_probes(struct afs_net *net, struct key *key,
205 struct afs_vlserver_list *vllist)
206 {
207 struct afs_vlserver *server;
208 struct afs_error e = {};
209 bool in_progress = false;
210 int i;
211
212 for (i = 0; i < vllist->nr_servers; i++) {
213 server = vllist->servers[i].server;
214 if (test_bit(AFS_VLSERVER_FL_PROBED, &server->flags))
215 continue;
216
217 if (!test_and_set_bit_lock(AFS_VLSERVER_FL_PROBING, &server->flags) &&
218 afs_do_probe_vlserver(net, server, key, i, &e))
219 in_progress = true;
220 }
221
222 return in_progress ? 0 : e.error;
223 }
224
225 /*
226 * Wait for the first as-yet untried server to respond.
227 */
228 int afs_wait_for_vl_probes(struct afs_vlserver_list *vllist,
229 unsigned long untried)
230 {
231 struct wait_queue_entry *waits;
232 struct afs_vlserver *server;
233 unsigned int rtt = UINT_MAX, rtt_s;
234 bool have_responders = false;
235 int pref = -1, i;
236
237 _enter("%u,%lx", vllist->nr_servers, untried);
238
239 /* Only wait for servers that have a probe outstanding. */
240 for (i = 0; i < vllist->nr_servers; i++) {
241 if (test_bit(i, &untried)) {
242 server = vllist->servers[i].server;
243 if (!test_bit(AFS_VLSERVER_FL_PROBING, &server->flags))
244 __clear_bit(i, &untried);
245 if (server->probe.flags & AFS_VLSERVER_PROBE_RESPONDED)
246 have_responders = true;
247 }
248 }
249 if (have_responders || !untried)
250 return 0;
251
252 waits = kmalloc(array_size(vllist->nr_servers, sizeof(*waits)), GFP_KERNEL);
253 if (!waits)
254 return -ENOMEM;
255
256 for (i = 0; i < vllist->nr_servers; i++) {
257 if (test_bit(i, &untried)) {
258 server = vllist->servers[i].server;
259 init_waitqueue_entry(&waits[i], current);
260 add_wait_queue(&server->probe_wq, &waits[i]);
261 }
262 }
263
264 for (;;) {
265 bool still_probing = false;
266
267 set_current_state(TASK_INTERRUPTIBLE);
268 for (i = 0; i < vllist->nr_servers; i++) {
269 if (test_bit(i, &untried)) {
270 server = vllist->servers[i].server;
271 if (server->probe.flags & AFS_VLSERVER_PROBE_RESPONDED)
272 goto stop;
273 if (test_bit(AFS_VLSERVER_FL_PROBING, &server->flags))
274 still_probing = true;
275 }
276 }
277
278 if (!still_probing || signal_pending(current))
279 goto stop;
280 schedule();
281 }
282
283 stop:
284 set_current_state(TASK_RUNNING);
285
286 for (i = 0; i < vllist->nr_servers; i++) {
287 if (test_bit(i, &untried)) {
288 server = vllist->servers[i].server;
289 rtt_s = READ_ONCE(server->rtt);
290 if (test_bit(AFS_VLSERVER_FL_RESPONDING, &server->flags) &&
291 rtt_s < rtt) {
292 pref = i;
293 rtt = rtt_s;
294 }
295
296 remove_wait_queue(&server->probe_wq, &waits[i]);
297 }
298 }
299
300 kfree(waits);
301
302 if (pref == -1 && signal_pending(current))
303 return -ERESTARTSYS;
304
305 if (pref >= 0)
306 vllist->preferred = pref;
307
308 _leave(" = 0 [%u]", pref);
309 return 0;
310 }
311
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