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3bf0fb6f DH |
1 | /* AFS fileserver probing |
2 | * | |
3 | * Copyright (C) 2018 Red Hat, Inc. All Rights Reserved. | |
4 | * Written by David Howells (dhowells@redhat.com) | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or | |
7 | * modify it under the terms of the GNU General Public Licence | |
8 | * as published by the Free Software Foundation; either version | |
9 | * 2 of the Licence, or (at your option) any later version. | |
10 | */ | |
11 | ||
12 | #include <linux/sched.h> | |
13 | #include <linux/slab.h> | |
14 | #include "afs_fs.h" | |
15 | #include "internal.h" | |
16 | #include "protocol_yfs.h" | |
17 | ||
18 | static bool afs_fs_probe_done(struct afs_server *server) | |
19 | { | |
20 | if (!atomic_dec_and_test(&server->probe_outstanding)) | |
21 | return false; | |
22 | ||
23 | wake_up_var(&server->probe_outstanding); | |
24 | clear_bit_unlock(AFS_SERVER_FL_PROBING, &server->flags); | |
25 | wake_up_bit(&server->flags, AFS_SERVER_FL_PROBING); | |
26 | return true; | |
27 | } | |
28 | ||
29 | /* | |
30 | * Process the result of probing a fileserver. This is called after successful | |
31 | * or failed delivery of an FS.GetCapabilities operation. | |
32 | */ | |
33 | void afs_fileserver_probe_result(struct afs_call *call) | |
34 | { | |
35 | struct afs_addr_list *alist = call->alist; | |
36 | struct afs_server *server = call->reply[0]; | |
37 | unsigned int server_index = (long)call->reply[1]; | |
38 | unsigned int index = call->addr_ix; | |
39 | unsigned int rtt = UINT_MAX; | |
40 | bool have_result = false; | |
41 | u64 _rtt; | |
42 | int ret = call->error; | |
43 | ||
44 | _enter("%pU,%u", &server->uuid, index); | |
45 | ||
46 | spin_lock(&server->probe_lock); | |
47 | ||
48 | switch (ret) { | |
49 | case 0: | |
50 | server->probe.error = 0; | |
51 | goto responded; | |
52 | case -ECONNABORTED: | |
53 | if (!server->probe.responded) { | |
54 | server->probe.abort_code = call->abort_code; | |
55 | server->probe.error = ret; | |
56 | } | |
57 | goto responded; | |
58 | case -ENOMEM: | |
59 | case -ENONET: | |
60 | server->probe.local_failure = true; | |
61 | afs_io_error(call, afs_io_error_fs_probe_fail); | |
62 | goto out; | |
63 | case -ECONNRESET: /* Responded, but call expired. */ | |
4584ae96 DH |
64 | case -ERFKILL: |
65 | case -EADDRNOTAVAIL: | |
3bf0fb6f DH |
66 | case -ENETUNREACH: |
67 | case -EHOSTUNREACH: | |
4584ae96 | 68 | case -EHOSTDOWN: |
3bf0fb6f DH |
69 | case -ECONNREFUSED: |
70 | case -ETIMEDOUT: | |
71 | case -ETIME: | |
72 | default: | |
73 | clear_bit(index, &alist->responded); | |
74 | set_bit(index, &alist->failed); | |
75 | if (!server->probe.responded && | |
76 | (server->probe.error == 0 || | |
77 | server->probe.error == -ETIMEDOUT || | |
78 | server->probe.error == -ETIME)) | |
79 | server->probe.error = ret; | |
80 | afs_io_error(call, afs_io_error_fs_probe_fail); | |
81 | goto out; | |
82 | } | |
83 | ||
84 | responded: | |
85 | set_bit(index, &alist->responded); | |
86 | clear_bit(index, &alist->failed); | |
87 | ||
88 | if (call->service_id == YFS_FS_SERVICE) { | |
89 | server->probe.is_yfs = true; | |
90 | set_bit(AFS_SERVER_FL_IS_YFS, &server->flags); | |
91 | alist->addrs[index].srx_service = call->service_id; | |
92 | } else { | |
93 | server->probe.not_yfs = true; | |
94 | if (!server->probe.is_yfs) { | |
95 | clear_bit(AFS_SERVER_FL_IS_YFS, &server->flags); | |
96 | alist->addrs[index].srx_service = call->service_id; | |
97 | } | |
98 | } | |
99 | ||
100 | /* Get the RTT and scale it to fit into a 32-bit value that represents | |
101 | * over a minute of time so that we can access it with one instruction | |
102 | * on a 32-bit system. | |
103 | */ | |
104 | _rtt = rxrpc_kernel_get_rtt(call->net->socket, call->rxcall); | |
105 | _rtt /= 64; | |
106 | rtt = (_rtt > UINT_MAX) ? UINT_MAX : _rtt; | |
107 | if (rtt < server->probe.rtt) { | |
108 | server->probe.rtt = rtt; | |
109 | alist->preferred = index; | |
110 | have_result = true; | |
111 | } | |
112 | ||
113 | smp_wmb(); /* Set rtt before responded. */ | |
114 | server->probe.responded = true; | |
115 | set_bit(AFS_SERVER_FL_PROBED, &server->flags); | |
116 | out: | |
117 | spin_unlock(&server->probe_lock); | |
118 | ||
119 | _debug("probe [%u][%u] %pISpc rtt=%u ret=%d", | |
120 | server_index, index, &alist->addrs[index].transport, | |
121 | (unsigned int)rtt, ret); | |
122 | ||
123 | have_result |= afs_fs_probe_done(server); | |
124 | if (have_result) { | |
125 | server->probe.have_result = true; | |
126 | wake_up_var(&server->probe.have_result); | |
127 | wake_up_all(&server->probe_wq); | |
128 | } | |
129 | } | |
130 | ||
131 | /* | |
132 | * Probe all of a fileserver's addresses to find out the best route and to | |
133 | * query its capabilities. | |
134 | */ | |
135 | static int afs_do_probe_fileserver(struct afs_net *net, | |
136 | struct afs_server *server, | |
137 | struct key *key, | |
4584ae96 DH |
138 | unsigned int server_index, |
139 | struct afs_error *_e) | |
3bf0fb6f DH |
140 | { |
141 | struct afs_addr_cursor ac = { | |
142 | .index = 0, | |
143 | }; | |
4584ae96 DH |
144 | bool in_progress = false; |
145 | int err; | |
3bf0fb6f DH |
146 | |
147 | _enter("%pU", &server->uuid); | |
148 | ||
149 | read_lock(&server->fs_lock); | |
150 | ac.alist = rcu_dereference_protected(server->addresses, | |
151 | lockdep_is_held(&server->fs_lock)); | |
152 | read_unlock(&server->fs_lock); | |
153 | ||
154 | atomic_set(&server->probe_outstanding, ac.alist->nr_addrs); | |
155 | memset(&server->probe, 0, sizeof(server->probe)); | |
156 | server->probe.rtt = UINT_MAX; | |
157 | ||
158 | for (ac.index = 0; ac.index < ac.alist->nr_addrs; ac.index++) { | |
4584ae96 | 159 | err = afs_fs_get_capabilities(net, server, &ac, key, server_index, |
3bf0fb6f | 160 | true); |
4584ae96 DH |
161 | if (err == -EINPROGRESS) |
162 | in_progress = true; | |
163 | else | |
164 | afs_prioritise_error(_e, err, ac.abort_code); | |
3bf0fb6f DH |
165 | } |
166 | ||
4584ae96 DH |
167 | if (!in_progress) |
168 | afs_fs_probe_done(server); | |
169 | return in_progress; | |
3bf0fb6f DH |
170 | } |
171 | ||
172 | /* | |
173 | * Send off probes to all unprobed servers. | |
174 | */ | |
175 | int afs_probe_fileservers(struct afs_net *net, struct key *key, | |
176 | struct afs_server_list *list) | |
177 | { | |
178 | struct afs_server *server; | |
4584ae96 DH |
179 | struct afs_error e; |
180 | bool in_progress = false; | |
181 | int i; | |
3bf0fb6f | 182 | |
4584ae96 DH |
183 | e.error = 0; |
184 | e.responded = false; | |
3bf0fb6f DH |
185 | for (i = 0; i < list->nr_servers; i++) { |
186 | server = list->servers[i].server; | |
187 | if (test_bit(AFS_SERVER_FL_PROBED, &server->flags)) | |
188 | continue; | |
189 | ||
4584ae96 DH |
190 | if (!test_and_set_bit_lock(AFS_SERVER_FL_PROBING, &server->flags) && |
191 | afs_do_probe_fileserver(net, server, key, i, &e)) | |
192 | in_progress = true; | |
3bf0fb6f DH |
193 | } |
194 | ||
4584ae96 | 195 | return in_progress ? 0 : e.error; |
3bf0fb6f DH |
196 | } |
197 | ||
198 | /* | |
199 | * Wait for the first as-yet untried fileserver to respond. | |
200 | */ | |
201 | int afs_wait_for_fs_probes(struct afs_server_list *slist, unsigned long untried) | |
202 | { | |
203 | struct wait_queue_entry *waits; | |
204 | struct afs_server *server; | |
205 | unsigned int rtt = UINT_MAX; | |
206 | bool have_responders = false; | |
207 | int pref = -1, i; | |
208 | ||
209 | _enter("%u,%lx", slist->nr_servers, untried); | |
210 | ||
211 | /* Only wait for servers that have a probe outstanding. */ | |
212 | for (i = 0; i < slist->nr_servers; i++) { | |
213 | if (test_bit(i, &untried)) { | |
214 | server = slist->servers[i].server; | |
215 | if (!test_bit(AFS_SERVER_FL_PROBING, &server->flags)) | |
216 | __clear_bit(i, &untried); | |
217 | if (server->probe.responded) | |
218 | have_responders = true; | |
219 | } | |
220 | } | |
221 | if (have_responders || !untried) | |
222 | return 0; | |
223 | ||
224 | waits = kmalloc(array_size(slist->nr_servers, sizeof(*waits)), GFP_KERNEL); | |
225 | if (!waits) | |
226 | return -ENOMEM; | |
227 | ||
228 | for (i = 0; i < slist->nr_servers; i++) { | |
229 | if (test_bit(i, &untried)) { | |
230 | server = slist->servers[i].server; | |
231 | init_waitqueue_entry(&waits[i], current); | |
232 | add_wait_queue(&server->probe_wq, &waits[i]); | |
233 | } | |
234 | } | |
235 | ||
236 | for (;;) { | |
237 | bool still_probing = false; | |
238 | ||
239 | set_current_state(TASK_INTERRUPTIBLE); | |
240 | for (i = 0; i < slist->nr_servers; i++) { | |
241 | if (test_bit(i, &untried)) { | |
242 | server = slist->servers[i].server; | |
243 | if (server->probe.responded) | |
244 | goto stop; | |
245 | if (test_bit(AFS_SERVER_FL_PROBING, &server->flags)) | |
246 | still_probing = true; | |
247 | } | |
248 | } | |
249 | ||
08d405c8 | 250 | if (!still_probing || signal_pending(current)) |
3bf0fb6f DH |
251 | goto stop; |
252 | schedule(); | |
253 | } | |
254 | ||
255 | stop: | |
256 | set_current_state(TASK_RUNNING); | |
257 | ||
258 | for (i = 0; i < slist->nr_servers; i++) { | |
259 | if (test_bit(i, &untried)) { | |
260 | server = slist->servers[i].server; | |
261 | if (server->probe.responded && | |
262 | server->probe.rtt < rtt) { | |
263 | pref = i; | |
264 | rtt = server->probe.rtt; | |
265 | } | |
266 | ||
267 | remove_wait_queue(&server->probe_wq, &waits[i]); | |
268 | } | |
269 | } | |
270 | ||
271 | kfree(waits); | |
272 | ||
273 | if (pref == -1 && signal_pending(current)) | |
274 | return -ERESTARTSYS; | |
275 | ||
276 | if (pref >= 0) | |
277 | slist->preferred = pref; | |
278 | return 0; | |
279 | } |