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 afs_get_addrlist(ac.alist); 149 read_unlock(&server->fs_lock); 150 151 atomic_set(&server->probe_outstanding, ac.alist->nr_addrs); 152 memset(&server->probe, 0, sizeof(server->probe)); 153 server->probe.rtt = UINT_MAX; 154 155 for (ac.index = 0; ac.index < ac.alist->nr_addrs; ac.index++) { 156 call = afs_fs_get_capabilities(net, server, &ac, key, server_index); 157 if (!IS_ERR(call)) { 158 afs_put_call(call); 159 in_progress = true; 160 } else { 161 afs_prioritise_error(_e, PTR_ERR(call), ac.abort_code); 162 } 163 } 164 165 if (!in_progress) 166 afs_fs_probe_done(server); 167 afs_put_addrlist(ac.alist); 168 return in_progress; 169 } 170 171 /* 172 * Send off probes to all unprobed servers. 173 */ 174 int afs_probe_fileservers(struct afs_net *net, struct key *key, 175 struct afs_server_list *list) 176 { 177 struct afs_server *server; 178 struct afs_error e; 179 bool in_progress = false; 180 int i; 181 182 e.error = 0; 183 e.responded = false; 184 for (i = 0; i < list->nr_servers; i++) { 185 server = list->servers[i].server; 186 if (test_bit(AFS_SERVER_FL_PROBED, &server->flags)) 187 continue; 188 189 if (!test_and_set_bit_lock(AFS_SERVER_FL_PROBING, &server->flags) && 190 afs_do_probe_fileserver(net, server, key, i, &e)) 191 in_progress = true; 192 } 193 194 return in_progress ? 0 : e.error; 195 } 196 197 /* 198 * Wait for the first as-yet untried fileserver to respond. 199 */ 200 int afs_wait_for_fs_probes(struct afs_server_list *slist, unsigned long untried) 201 { 202 struct wait_queue_entry *waits; 203 struct afs_server *server; 204 unsigned int rtt = UINT_MAX; 205 bool have_responders = false; 206 int pref = -1, i; 207 208 _enter("%u,%lx", slist->nr_servers, untried); 209 210 /* Only wait for servers that have a probe outstanding. */ 211 for (i = 0; i < slist->nr_servers; i++) { 212 if (test_bit(i, &untried)) { 213 server = slist->servers[i].server; 214 if (!test_bit(AFS_SERVER_FL_PROBING, &server->flags)) 215 __clear_bit(i, &untried); 216 if (server->probe.responded) 217 have_responders = true; 218 } 219 } 220 if (have_responders || !untried) 221 return 0; 222 223 waits = kmalloc(array_size(slist->nr_servers, sizeof(*waits)), GFP_KERNEL); 224 if (!waits) 225 return -ENOMEM; 226 227 for (i = 0; i < slist->nr_servers; i++) { 228 if (test_bit(i, &untried)) { 229 server = slist->servers[i].server; 230 init_waitqueue_entry(&waits[i], current); 231 add_wait_queue(&server->probe_wq, &waits[i]); 232 } 233 } 234 235 for (;;) { 236 bool still_probing = false; 237 238 set_current_state(TASK_INTERRUPTIBLE); 239 for (i = 0; i < slist->nr_servers; i++) { 240 if (test_bit(i, &untried)) { 241 server = slist->servers[i].server; 242 if (server->probe.responded) 243 goto stop; 244 if (test_bit(AFS_SERVER_FL_PROBING, &server->flags)) 245 still_probing = true; 246 } 247 } 248 249 if (!still_probing || signal_pending(current)) 250 goto stop; 251 schedule(); 252 } 253 254 stop: 255 set_current_state(TASK_RUNNING); 256 257 for (i = 0; i < slist->nr_servers; i++) { 258 if (test_bit(i, &untried)) { 259 server = slist->servers[i].server; 260 if (server->probe.responded && 261 server->probe.rtt < rtt) { 262 pref = i; 263 rtt = server->probe.rtt; 264 } 265 266 remove_wait_queue(&server->probe_wq, &waits[i]); 267 } 268 } 269 270 kfree(waits); 271 272 if (pref == -1 && signal_pending(current)) 273 return -ERESTARTSYS; 274 275 if (pref >= 0) 276 slist->preferred = pref; 277 return 0; 278 } 279