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