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b4d0d230 | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
3bf0fb6f DH |
2 | /* AFS vlserver probing |
3 | * | |
4 | * Copyright (C) 2018 Red Hat, Inc. All Rights Reserved. | |
5 | * Written by David Howells (dhowells@redhat.com) | |
3bf0fb6f DH |
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 | static bool afs_vl_probe_done(struct afs_vlserver *server) | |
15 | { | |
16 | if (!atomic_dec_and_test(&server->probe_outstanding)) | |
17 | return false; | |
18 | ||
19 | wake_up_var(&server->probe_outstanding); | |
20 | clear_bit_unlock(AFS_VLSERVER_FL_PROBING, &server->flags); | |
21 | wake_up_bit(&server->flags, AFS_VLSERVER_FL_PROBING); | |
22 | return true; | |
23 | } | |
24 | ||
25 | /* | |
26 | * Process the result of probing a vlserver. This is called after successful | |
27 | * or failed delivery of an VL.GetCapabilities operation. | |
28 | */ | |
29 | void afs_vlserver_probe_result(struct afs_call *call) | |
30 | { | |
31 | struct afs_addr_list *alist = call->alist; | |
ffba718e DH |
32 | struct afs_vlserver *server = call->vlserver; |
33 | unsigned int server_index = call->server_index; | |
3bf0fb6f DH |
34 | unsigned int index = call->addr_ix; |
35 | unsigned int rtt = UINT_MAX; | |
36 | bool have_result = false; | |
37 | u64 _rtt; | |
38 | int ret = call->error; | |
39 | ||
40 | _enter("%s,%u,%u,%d,%d", server->name, server_index, index, ret, call->abort_code); | |
41 | ||
42 | spin_lock(&server->probe_lock); | |
43 | ||
44 | switch (ret) { | |
45 | case 0: | |
46 | server->probe.error = 0; | |
47 | goto responded; | |
48 | case -ECONNABORTED: | |
49 | if (!server->probe.responded) { | |
50 | server->probe.abort_code = call->abort_code; | |
51 | server->probe.error = ret; | |
52 | } | |
53 | goto responded; | |
54 | case -ENOMEM: | |
55 | case -ENONET: | |
56 | server->probe.local_failure = true; | |
57 | afs_io_error(call, afs_io_error_vl_probe_fail); | |
58 | goto out; | |
59 | case -ECONNRESET: /* Responded, but call expired. */ | |
4584ae96 DH |
60 | case -ERFKILL: |
61 | case -EADDRNOTAVAIL: | |
3bf0fb6f DH |
62 | case -ENETUNREACH: |
63 | case -EHOSTUNREACH: | |
4584ae96 | 64 | case -EHOSTDOWN: |
3bf0fb6f DH |
65 | case -ECONNREFUSED: |
66 | case -ETIMEDOUT: | |
67 | case -ETIME: | |
68 | default: | |
69 | clear_bit(index, &alist->responded); | |
70 | set_bit(index, &alist->failed); | |
71 | if (!server->probe.responded && | |
72 | (server->probe.error == 0 || | |
73 | server->probe.error == -ETIMEDOUT || | |
74 | server->probe.error == -ETIME)) | |
75 | server->probe.error = ret; | |
76 | afs_io_error(call, afs_io_error_vl_probe_fail); | |
77 | goto out; | |
78 | } | |
79 | ||
80 | responded: | |
81 | set_bit(index, &alist->responded); | |
82 | clear_bit(index, &alist->failed); | |
83 | ||
84 | if (call->service_id == YFS_VL_SERVICE) { | |
85 | server->probe.is_yfs = true; | |
86 | set_bit(AFS_VLSERVER_FL_IS_YFS, &server->flags); | |
87 | alist->addrs[index].srx_service = call->service_id; | |
88 | } else { | |
89 | server->probe.not_yfs = true; | |
90 | if (!server->probe.is_yfs) { | |
91 | clear_bit(AFS_VLSERVER_FL_IS_YFS, &server->flags); | |
92 | alist->addrs[index].srx_service = call->service_id; | |
93 | } | |
94 | } | |
95 | ||
96 | /* Get the RTT and scale it to fit into a 32-bit value that represents | |
97 | * over a minute of time so that we can access it with one instruction | |
98 | * on a 32-bit system. | |
99 | */ | |
100 | _rtt = rxrpc_kernel_get_rtt(call->net->socket, call->rxcall); | |
101 | _rtt /= 64; | |
102 | rtt = (_rtt > UINT_MAX) ? UINT_MAX : _rtt; | |
103 | if (rtt < server->probe.rtt) { | |
104 | server->probe.rtt = rtt; | |
105 | alist->preferred = index; | |
106 | have_result = true; | |
107 | } | |
108 | ||
109 | smp_wmb(); /* Set rtt before responded. */ | |
110 | server->probe.responded = true; | |
111 | set_bit(AFS_VLSERVER_FL_PROBED, &server->flags); | |
112 | out: | |
113 | spin_unlock(&server->probe_lock); | |
114 | ||
115 | _debug("probe [%u][%u] %pISpc rtt=%u ret=%d", | |
116 | server_index, index, &alist->addrs[index].transport, | |
117 | (unsigned int)rtt, ret); | |
118 | ||
119 | have_result |= afs_vl_probe_done(server); | |
120 | if (have_result) { | |
121 | server->probe.have_result = true; | |
122 | wake_up_var(&server->probe.have_result); | |
123 | wake_up_all(&server->probe_wq); | |
124 | } | |
125 | } | |
126 | ||
127 | /* | |
128 | * Probe all of a vlserver's addresses to find out the best route and to | |
129 | * query its capabilities. | |
130 | */ | |
4584ae96 DH |
131 | static bool afs_do_probe_vlserver(struct afs_net *net, |
132 | struct afs_vlserver *server, | |
133 | struct key *key, | |
134 | unsigned int server_index, | |
135 | struct afs_error *_e) | |
3bf0fb6f DH |
136 | { |
137 | struct afs_addr_cursor ac = { | |
138 | .index = 0, | |
139 | }; | |
0b9bf381 | 140 | struct afs_call *call; |
4584ae96 | 141 | bool in_progress = false; |
3bf0fb6f DH |
142 | |
143 | _enter("%s", server->name); | |
144 | ||
145 | read_lock(&server->lock); | |
146 | ac.alist = rcu_dereference_protected(server->addresses, | |
147 | lockdep_is_held(&server->lock)); | |
148 | read_unlock(&server->lock); | |
149 | ||
150 | atomic_set(&server->probe_outstanding, ac.alist->nr_addrs); | |
151 | memset(&server->probe, 0, sizeof(server->probe)); | |
152 | server->probe.rtt = UINT_MAX; | |
153 | ||
154 | for (ac.index = 0; ac.index < ac.alist->nr_addrs; ac.index++) { | |
0b9bf381 DH |
155 | call = afs_vl_get_capabilities(net, &ac, key, server, |
156 | server_index); | |
157 | if (!IS_ERR(call)) { | |
158 | afs_put_call(call); | |
4584ae96 | 159 | in_progress = true; |
0b9bf381 DH |
160 | } else { |
161 | afs_prioritise_error(_e, PTR_ERR(call), ac.abort_code); | |
162 | } | |
3bf0fb6f DH |
163 | } |
164 | ||
4584ae96 DH |
165 | if (!in_progress) |
166 | afs_vl_probe_done(server); | |
167 | return in_progress; | |
3bf0fb6f DH |
168 | } |
169 | ||
170 | /* | |
171 | * Send off probes to all unprobed servers. | |
172 | */ | |
173 | int afs_send_vl_probes(struct afs_net *net, struct key *key, | |
174 | struct afs_vlserver_list *vllist) | |
175 | { | |
176 | struct afs_vlserver *server; | |
4584ae96 DH |
177 | struct afs_error e; |
178 | bool in_progress = false; | |
179 | int i; | |
3bf0fb6f | 180 | |
4584ae96 DH |
181 | e.error = 0; |
182 | e.responded = false; | |
3bf0fb6f DH |
183 | for (i = 0; i < vllist->nr_servers; i++) { |
184 | server = vllist->servers[i].server; | |
185 | if (test_bit(AFS_VLSERVER_FL_PROBED, &server->flags)) | |
186 | continue; | |
187 | ||
4584ae96 DH |
188 | if (!test_and_set_bit_lock(AFS_VLSERVER_FL_PROBING, &server->flags) && |
189 | afs_do_probe_vlserver(net, server, key, i, &e)) | |
190 | in_progress = true; | |
3bf0fb6f DH |
191 | } |
192 | ||
4584ae96 | 193 | return in_progress ? 0 : e.error; |
3bf0fb6f DH |
194 | } |
195 | ||
196 | /* | |
197 | * Wait for the first as-yet untried server to respond. | |
198 | */ | |
199 | int afs_wait_for_vl_probes(struct afs_vlserver_list *vllist, | |
200 | unsigned long untried) | |
201 | { | |
202 | struct wait_queue_entry *waits; | |
203 | struct afs_vlserver *server; | |
204 | unsigned int rtt = UINT_MAX; | |
205 | bool have_responders = false; | |
206 | int pref = -1, i; | |
207 | ||
208 | _enter("%u,%lx", vllist->nr_servers, untried); | |
209 | ||
210 | /* Only wait for servers that have a probe outstanding. */ | |
211 | for (i = 0; i < vllist->nr_servers; i++) { | |
212 | if (test_bit(i, &untried)) { | |
213 | server = vllist->servers[i].server; | |
214 | if (!test_bit(AFS_VLSERVER_FL_PROBING, &server->flags)) | |
215 | __clear_bit(i, &untried); | |
216 | if (server->probe.responded) | |
217 | have_responders = true; | |
218 | } | |
219 | } | |
220 | if (have_responders || !untried) | |
221 | return 0; | |
222 | ||
223 | waits = kmalloc(array_size(vllist->nr_servers, sizeof(*waits)), GFP_KERNEL); | |
224 | if (!waits) | |
225 | return -ENOMEM; | |
226 | ||
227 | for (i = 0; i < vllist->nr_servers; i++) { | |
228 | if (test_bit(i, &untried)) { | |
229 | server = vllist->servers[i].server; | |
230 | init_waitqueue_entry(&waits[i], current); | |
231 | add_wait_queue(&server->probe_wq, &waits[i]); | |
232 | } | |
233 | } | |
234 | ||
235 | for (;;) { | |
236 | bool still_probing = false; | |
237 | ||
238 | set_current_state(TASK_INTERRUPTIBLE); | |
239 | for (i = 0; i < vllist->nr_servers; i++) { | |
240 | if (test_bit(i, &untried)) { | |
241 | server = vllist->servers[i].server; | |
242 | if (server->probe.responded) | |
243 | goto stop; | |
244 | if (test_bit(AFS_VLSERVER_FL_PROBING, &server->flags)) | |
245 | still_probing = true; | |
246 | } | |
247 | } | |
248 | ||
08d405c8 | 249 | if (!still_probing || signal_pending(current)) |
3bf0fb6f DH |
250 | goto stop; |
251 | schedule(); | |
252 | } | |
253 | ||
254 | stop: | |
255 | set_current_state(TASK_RUNNING); | |
256 | ||
257 | for (i = 0; i < vllist->nr_servers; i++) { | |
258 | if (test_bit(i, &untried)) { | |
259 | server = vllist->servers[i].server; | |
260 | if (server->probe.responded && | |
261 | server->probe.rtt < rtt) { | |
262 | pref = i; | |
263 | rtt = server->probe.rtt; | |
264 | } | |
265 | ||
266 | remove_wait_queue(&server->probe_wq, &waits[i]); | |
267 | } | |
268 | } | |
269 | ||
270 | kfree(waits); | |
271 | ||
272 | if (pref == -1 && signal_pending(current)) | |
273 | return -ERESTARTSYS; | |
274 | ||
275 | if (pref >= 0) | |
276 | vllist->preferred = pref; | |
277 | ||
278 | _leave(" = 0 [%u]", pref); | |
279 | return 0; | |
280 | } |