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