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b4d0d230 | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
3bf0fb6f DH |
2 | /* AFS fileserver 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_fs_probe_done(struct afs_server *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_SERVER_FL_PROBING, &server->flags); | |
21 | wake_up_bit(&server->flags, AFS_SERVER_FL_PROBING); | |
22 | return true; | |
23 | } | |
24 | ||
25 | /* | |
26 | * Process the result of probing a fileserver. This is called after successful | |
27 | * or failed delivery of an FS.GetCapabilities operation. | |
28 | */ | |
29 | void afs_fileserver_probe_result(struct afs_call *call) | |
30 | { | |
31 | struct afs_addr_list *alist = call->alist; | |
ffba718e DH |
32 | struct afs_server *server = call->server; |
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("%pU,%u", &server->uuid, index); | |
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_fs_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_fs_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_FS_SERVICE) { | |
85 | server->probe.is_yfs = true; | |
86 | set_bit(AFS_SERVER_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_SERVER_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_SERVER_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_fs_probe_done(server); | |
be59167c | 120 | if (have_result) |
3bf0fb6f | 121 | wake_up_all(&server->probe_wq); |
3bf0fb6f DH |
122 | } |
123 | ||
124 | /* | |
125 | * Probe all of a fileserver's addresses to find out the best route and to | |
126 | * query its capabilities. | |
127 | */ | |
128 | static int afs_do_probe_fileserver(struct afs_net *net, | |
129 | struct afs_server *server, | |
130 | struct key *key, | |
4584ae96 DH |
131 | unsigned int server_index, |
132 | struct afs_error *_e) | |
3bf0fb6f DH |
133 | { |
134 | struct afs_addr_cursor ac = { | |
135 | .index = 0, | |
136 | }; | |
0b9bf381 | 137 | struct afs_call *call; |
4584ae96 | 138 | bool in_progress = false; |
3bf0fb6f DH |
139 | |
140 | _enter("%pU", &server->uuid); | |
141 | ||
142 | read_lock(&server->fs_lock); | |
143 | ac.alist = rcu_dereference_protected(server->addresses, | |
144 | lockdep_is_held(&server->fs_lock)); | |
9efcc4a1 | 145 | afs_get_addrlist(ac.alist); |
3bf0fb6f DH |
146 | read_unlock(&server->fs_lock); |
147 | ||
148 | atomic_set(&server->probe_outstanding, ac.alist->nr_addrs); | |
149 | memset(&server->probe, 0, sizeof(server->probe)); | |
150 | server->probe.rtt = UINT_MAX; | |
151 | ||
152 | for (ac.index = 0; ac.index < ac.alist->nr_addrs; ac.index++) { | |
0b9bf381 DH |
153 | call = afs_fs_get_capabilities(net, server, &ac, key, server_index); |
154 | if (!IS_ERR(call)) { | |
155 | afs_put_call(call); | |
4584ae96 | 156 | in_progress = true; |
0b9bf381 DH |
157 | } else { |
158 | afs_prioritise_error(_e, PTR_ERR(call), ac.abort_code); | |
159 | } | |
3bf0fb6f DH |
160 | } |
161 | ||
4584ae96 DH |
162 | if (!in_progress) |
163 | afs_fs_probe_done(server); | |
9efcc4a1 | 164 | afs_put_addrlist(ac.alist); |
4584ae96 | 165 | return in_progress; |
3bf0fb6f DH |
166 | } |
167 | ||
168 | /* | |
169 | * Send off probes to all unprobed servers. | |
170 | */ | |
171 | int afs_probe_fileservers(struct afs_net *net, struct key *key, | |
172 | struct afs_server_list *list) | |
173 | { | |
174 | struct afs_server *server; | |
4584ae96 DH |
175 | struct afs_error e; |
176 | bool in_progress = false; | |
177 | int i; | |
3bf0fb6f | 178 | |
4584ae96 DH |
179 | e.error = 0; |
180 | e.responded = false; | |
3bf0fb6f DH |
181 | for (i = 0; i < list->nr_servers; i++) { |
182 | server = list->servers[i].server; | |
183 | if (test_bit(AFS_SERVER_FL_PROBED, &server->flags)) | |
184 | continue; | |
185 | ||
4584ae96 DH |
186 | if (!test_and_set_bit_lock(AFS_SERVER_FL_PROBING, &server->flags) && |
187 | afs_do_probe_fileserver(net, server, key, i, &e)) | |
188 | in_progress = true; | |
3bf0fb6f DH |
189 | } |
190 | ||
4584ae96 | 191 | return in_progress ? 0 : e.error; |
3bf0fb6f DH |
192 | } |
193 | ||
194 | /* | |
195 | * Wait for the first as-yet untried fileserver to respond. | |
196 | */ | |
197 | int afs_wait_for_fs_probes(struct afs_server_list *slist, unsigned long untried) | |
198 | { | |
199 | struct wait_queue_entry *waits; | |
200 | struct afs_server *server; | |
201 | unsigned int rtt = UINT_MAX; | |
202 | bool have_responders = false; | |
203 | int pref = -1, i; | |
204 | ||
205 | _enter("%u,%lx", slist->nr_servers, untried); | |
206 | ||
207 | /* Only wait for servers that have a probe outstanding. */ | |
208 | for (i = 0; i < slist->nr_servers; i++) { | |
209 | if (test_bit(i, &untried)) { | |
210 | server = slist->servers[i].server; | |
211 | if (!test_bit(AFS_SERVER_FL_PROBING, &server->flags)) | |
212 | __clear_bit(i, &untried); | |
213 | if (server->probe.responded) | |
214 | have_responders = true; | |
215 | } | |
216 | } | |
217 | if (have_responders || !untried) | |
218 | return 0; | |
219 | ||
220 | waits = kmalloc(array_size(slist->nr_servers, sizeof(*waits)), GFP_KERNEL); | |
221 | if (!waits) | |
222 | return -ENOMEM; | |
223 | ||
224 | for (i = 0; i < slist->nr_servers; i++) { | |
225 | if (test_bit(i, &untried)) { | |
226 | server = slist->servers[i].server; | |
227 | init_waitqueue_entry(&waits[i], current); | |
228 | add_wait_queue(&server->probe_wq, &waits[i]); | |
229 | } | |
230 | } | |
231 | ||
232 | for (;;) { | |
233 | bool still_probing = false; | |
234 | ||
235 | set_current_state(TASK_INTERRUPTIBLE); | |
236 | for (i = 0; i < slist->nr_servers; i++) { | |
237 | if (test_bit(i, &untried)) { | |
238 | server = slist->servers[i].server; | |
239 | if (server->probe.responded) | |
240 | goto stop; | |
241 | if (test_bit(AFS_SERVER_FL_PROBING, &server->flags)) | |
242 | still_probing = true; | |
243 | } | |
244 | } | |
245 | ||
08d405c8 | 246 | if (!still_probing || signal_pending(current)) |
3bf0fb6f DH |
247 | goto stop; |
248 | schedule(); | |
249 | } | |
250 | ||
251 | stop: | |
252 | set_current_state(TASK_RUNNING); | |
253 | ||
254 | for (i = 0; i < slist->nr_servers; i++) { | |
255 | if (test_bit(i, &untried)) { | |
256 | server = slist->servers[i].server; | |
257 | if (server->probe.responded && | |
258 | server->probe.rtt < rtt) { | |
259 | pref = i; | |
260 | rtt = server->probe.rtt; | |
261 | } | |
262 | ||
263 | remove_wait_queue(&server->probe_wq, &waits[i]); | |
264 | } | |
265 | } | |
266 | ||
267 | kfree(waits); | |
268 | ||
269 | if (pref == -1 && signal_pending(current)) | |
270 | return -ERESTARTSYS; | |
271 | ||
272 | if (pref >= 0) | |
273 | slist->preferred = pref; | |
274 | return 0; | |
275 | } |