1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* AFS fileserver probing
4 * Copyright (C) 2018 Red Hat, Inc. All Rights Reserved.
5 * Written by David Howells (dhowells@redhat.com)
8 #include <linux/sched.h>
9 #include <linux/slab.h>
12 #include "protocol_yfs.h"
14 static bool afs_fs_probe_done(struct afs_server *server)
16 if (!atomic_dec_and_test(&server->probe_outstanding))
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);
26 * Process the result of probing a fileserver. This is called after successful
27 * or failed delivery of an FS.GetCapabilities operation.
29 void afs_fileserver_probe_result(struct afs_call *call)
31 struct afs_addr_list *alist = call->alist;
32 struct afs_server *server = call->server;
33 unsigned int server_index = call->server_index;
34 unsigned int index = call->addr_ix;
35 unsigned int rtt = UINT_MAX;
36 bool have_result = false;
38 int ret = call->error;
40 _enter("%pU,%u", &server->uuid, index);
42 spin_lock(&server->probe_lock);
46 server->probe.error = 0;
49 if (!server->probe.responded) {
50 server->probe.abort_code = call->abort_code;
51 server->probe.error = ret;
56 server->probe.local_failure = true;
57 afs_io_error(call, afs_io_error_fs_probe_fail);
59 case -ECONNRESET: /* Responded, but call expired. */
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);
81 set_bit(index, &alist->responded);
82 clear_bit(index, &alist->failed);
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;
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;
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
100 _rtt = rxrpc_kernel_get_rtt(call->net->socket, call->rxcall);
102 rtt = (_rtt > UINT_MAX) ? UINT_MAX : _rtt;
103 if (rtt < server->probe.rtt) {
104 server->probe.rtt = rtt;
105 alist->preferred = index;
109 smp_wmb(); /* Set rtt before responded. */
110 server->probe.responded = true;
111 set_bit(AFS_SERVER_FL_PROBED, &server->flags);
113 spin_unlock(&server->probe_lock);
115 _debug("probe [%u][%u] %pISpc rtt=%u ret=%d",
116 server_index, index, &alist->addrs[index].transport,
117 (unsigned int)rtt, ret);
119 have_result |= afs_fs_probe_done(server);
121 wake_up_all(&server->probe_wq);
125 * Probe all of a fileserver's addresses to find out the best route and to
126 * query its capabilities.
128 static int afs_do_probe_fileserver(struct afs_net *net,
129 struct afs_server *server,
131 unsigned int server_index,
132 struct afs_error *_e)
134 struct afs_addr_cursor ac = {
137 struct afs_call *call;
138 bool in_progress = false;
140 _enter("%pU", &server->uuid);
142 read_lock(&server->fs_lock);
143 ac.alist = rcu_dereference_protected(server->addresses,
144 lockdep_is_held(&server->fs_lock));
145 afs_get_addrlist(ac.alist);
146 read_unlock(&server->fs_lock);
148 atomic_set(&server->probe_outstanding, ac.alist->nr_addrs);
149 memset(&server->probe, 0, sizeof(server->probe));
150 server->probe.rtt = UINT_MAX;
152 for (ac.index = 0; ac.index < ac.alist->nr_addrs; ac.index++) {
153 call = afs_fs_get_capabilities(net, server, &ac, key, server_index);
158 afs_prioritise_error(_e, PTR_ERR(call), ac.abort_code);
163 afs_fs_probe_done(server);
164 afs_put_addrlist(ac.alist);
169 * Send off probes to all unprobed servers.
171 int afs_probe_fileservers(struct afs_net *net, struct key *key,
172 struct afs_server_list *list)
174 struct afs_server *server;
176 bool in_progress = false;
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))
186 if (!test_and_set_bit_lock(AFS_SERVER_FL_PROBING, &server->flags) &&
187 afs_do_probe_fileserver(net, server, key, i, &e))
191 return in_progress ? 0 : e.error;
195 * Wait for the first as-yet untried fileserver to respond.
197 int afs_wait_for_fs_probes(struct afs_server_list *slist, unsigned long untried)
199 struct wait_queue_entry *waits;
200 struct afs_server *server;
201 unsigned int rtt = UINT_MAX;
202 bool have_responders = false;
205 _enter("%u,%lx", slist->nr_servers, untried);
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;
217 if (have_responders || !untried)
220 waits = kmalloc(array_size(slist->nr_servers, sizeof(*waits)), GFP_KERNEL);
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]);
233 bool still_probing = false;
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)
241 if (test_bit(AFS_SERVER_FL_PROBING, &server->flags))
242 still_probing = true;
246 if (!still_probing || signal_pending(current))
252 set_current_state(TASK_RUNNING);
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) {
260 rtt = server->probe.rtt;
263 remove_wait_queue(&server->probe_wq, &waits[i]);
269 if (pref == -1 && signal_pending(current))
273 slist->preferred = pref;