1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* AFS fileserver 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_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; 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; 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. */ 60 case -ERFKILL: 61 case -EADDRNOTAVAIL: 62 case -ENETUNREACH: 63 case -EHOSTUNREACH: 64 case -EHOSTDOWN: 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); 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 fileserver's addresses to find out the best route and to 129 * query its capabilities. 130 */ 131 static int afs_do_probe_fileserver(struct afs_net *net, 132 struct afs_server *server, 133 struct key *key, 134 unsigned int server_index, 135 struct afs_error *_e) 136 { 137 struct afs_addr_cursor ac = { 138 .index = 0, 139 }; 140 struct afs_call *call; 141 bool in_progress = false; 142 143 _enter("%pU", &server->uuid); 144 145 read_lock(&server->fs_lock); 146 ac.alist = rcu_dereference_protected(server->addresses, 147 lockdep_is_held(&server->fs_lock)); 148 read_unlock(&server->fs_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++) { 155 call = afs_fs_get_capabilities(net, server, &ac, key, server_index); 156 if (!IS_ERR(call)) { 157 afs_put_call(call); 158 in_progress = true; 159 } else { 160 afs_prioritise_error(_e, PTR_ERR(call), ac.abort_code); 161 } 162 } 163 164 if (!in_progress) 165 afs_fs_probe_done(server); 166 return in_progress; 167 } 168 169 /* 170 * Send off probes to all unprobed servers. 171 */ 172 int afs_probe_fileservers(struct afs_net *net, struct key *key, 173 struct afs_server_list *list) 174 { 175 struct afs_server *server; 176 struct afs_error e; 177 bool in_progress = false; 178 int i; 179 180 e.error = 0; 181 e.responded = false; 182 for (i = 0; i < list->nr_servers; i++) { 183 server = list->servers[i].server; 184 if (test_bit(AFS_SERVER_FL_PROBED, &server->flags)) 185 continue; 186 187 if (!test_and_set_bit_lock(AFS_SERVER_FL_PROBING, &server->flags) && 188 afs_do_probe_fileserver(net, server, key, i, &e)) 189 in_progress = true; 190 } 191 192 return in_progress ? 0 : e.error; 193 } 194 195 /* 196 * Wait for the first as-yet untried fileserver to respond. 197 */ 198 int afs_wait_for_fs_probes(struct afs_server_list *slist, unsigned long untried) 199 { 200 struct wait_queue_entry *waits; 201 struct afs_server *server; 202 unsigned int rtt = UINT_MAX; 203 bool have_responders = false; 204 int pref = -1, i; 205 206 _enter("%u,%lx", slist->nr_servers, untried); 207 208 /* Only wait for servers that have a probe outstanding. */ 209 for (i = 0; i < slist->nr_servers; i++) { 210 if (test_bit(i, &untried)) { 211 server = slist->servers[i].server; 212 if (!test_bit(AFS_SERVER_FL_PROBING, &server->flags)) 213 __clear_bit(i, &untried); 214 if (server->probe.responded) 215 have_responders = true; 216 } 217 } 218 if (have_responders || !untried) 219 return 0; 220 221 waits = kmalloc(array_size(slist->nr_servers, sizeof(*waits)), GFP_KERNEL); 222 if (!waits) 223 return -ENOMEM; 224 225 for (i = 0; i < slist->nr_servers; i++) { 226 if (test_bit(i, &untried)) { 227 server = slist->servers[i].server; 228 init_waitqueue_entry(&waits[i], current); 229 add_wait_queue(&server->probe_wq, &waits[i]); 230 } 231 } 232 233 for (;;) { 234 bool still_probing = false; 235 236 set_current_state(TASK_INTERRUPTIBLE); 237 for (i = 0; i < slist->nr_servers; i++) { 238 if (test_bit(i, &untried)) { 239 server = slist->servers[i].server; 240 if (server->probe.responded) 241 goto stop; 242 if (test_bit(AFS_SERVER_FL_PROBING, &server->flags)) 243 still_probing = true; 244 } 245 } 246 247 if (!still_probing || signal_pending(current)) 248 goto stop; 249 schedule(); 250 } 251 252 stop: 253 set_current_state(TASK_RUNNING); 254 255 for (i = 0; i < slist->nr_servers; i++) { 256 if (test_bit(i, &untried)) { 257 server = slist->servers[i].server; 258 if (server->probe.responded && 259 server->probe.rtt < rtt) { 260 pref = i; 261 rtt = server->probe.rtt; 262 } 263 264 remove_wait_queue(&server->probe_wq, &waits[i]); 265 } 266 } 267 268 kfree(waits); 269 270 if (pref == -1 && signal_pending(current)) 271 return -ERESTARTSYS; 272 273 if (pref >= 0) 274 slist->preferred = pref; 275 return 0; 276 } 277