1 /* daemon.c: kernel part of Vinum daemon */ 2 /*- 3 * Copyright (c) 1997, 1998 4 * Nan Yang Computer Services Limited. All rights reserved. 5 * 6 * This software is distributed under the so-called ``Berkeley 7 * License'': 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 3. All advertising materials mentioning features or use of this software 18 * must display the following acknowledgement: 19 * This product includes software developed by Nan Yang Computer 20 * Services Limited. 21 * 4. Neither the name of the Company nor the names of its contributors 22 * may be used to endorse or promote products derived from this software 23 * without specific prior written permission. 24 * 25 * This software is provided ``as is'', and any express or implied 26 * warranties, including, but not limited to, the implied warranties of 27 * merchantability and fitness for a particular purpose are disclaimed. 28 * In no event shall the company or contributors be liable for any 29 * direct, indirect, incidental, special, exemplary, or consequential 30 * damages (including, but not limited to, procurement of substitute 31 * goods or services; loss of use, data, or profits; or business 32 * interruption) however caused and on any theory of liability, whether 33 * in contract, strict liability, or tort (including negligence or 34 * otherwise) arising in any way out of the use of this software, even if 35 * advised of the possibility of such damage. 36 * 37 * $Id: vinumdaemon.c,v 1.8 2000/01/03 05:22:03 grog Exp grog $ 38 * $FreeBSD: src/sys/dev/vinum/vinumdaemon.c,v 1.16 2000/01/05 06:03:56 grog Exp $ 39 */ 40 41 #include "vinumhdr.h" 42 #include "request.h" 43 44 #ifdef VINUMDEBUG 45 #include <sys/reboot.h> 46 #endif 47 48 /* declarations */ 49 void recover_io(struct request *rq); 50 51 int daemon_options = 0; /* options */ 52 int daemonpid; /* PID of daemon */ 53 struct daemonq *daemonq; /* daemon's work queue */ 54 struct daemonq *dqend; /* and the end of the queue */ 55 56 /* 57 * We normally call Malloc to get a queue element. In interrupt 58 * context, we can't guarantee that we'll get one, since we're not 59 * allowed to wait. If malloc fails, use one of these elements. 60 */ 61 62 #define INTQSIZE 4 63 struct daemonq intq[INTQSIZE]; /* queue elements for interrupt context */ 64 struct daemonq *intqp; /* and pointer in it */ 65 66 void 67 vinum_daemon(void) 68 { 69 struct daemonq *request; 70 71 curproc->p_flags |= P_SYSTEM; /* we're a system process */ 72 daemon_save_config(); /* start by saving the configuration */ 73 daemonpid = curproc->p_pid; /* mark our territory */ 74 while (1) { 75 tsleep(&vinum_daemon, 0, "vinum", 0); /* wait for something to happen */ 76 77 /* 78 * It's conceivable that, as the result of an 79 * I/O error, we'll be out of action long 80 * enough that another daemon gets started. 81 * That's OK, just give up gracefully. 82 */ 83 if (curproc->p_pid != daemonpid) { /* we've been ousted in our sleep */ 84 if (daemon_options & daemon_verbose) 85 log(LOG_INFO, "vinum: abdicating\n"); 86 return; 87 } 88 while (daemonq != NULL) { /* we have work to do, */ 89 crit_enter(); 90 request = daemonq; /* get the request */ 91 daemonq = daemonq->next; /* and detach it */ 92 if (daemonq == NULL) /* got to the end, */ 93 dqend = NULL; /* no end any more */ 94 crit_exit(); 95 96 switch (request->type) { 97 /* 98 * We had an I/O error on a request. Go through the 99 * request and try to salvage it 100 */ 101 case daemonrq_ioerror: 102 if (daemon_options & daemon_verbose) { 103 struct request *rq = request->info.rq; 104 105 log(LOG_WARNING, 106 "vinum: recovering I/O request: %p\n%s dev %d.%d, offset 0x%012llx, length %d\n", 107 rq, 108 (rq->bio->bio_buf->b_cmd == BUF_CMD_READ) ? "Read" : "Write", 109 major((cdev_t)rq->bio->bio_driver_info), 110 minor((cdev_t)rq->bio->bio_driver_info), 111 (long long)rq->bio->bio_offset, 112 rq->bio->bio_buf->b_bcount); 113 } 114 recover_io(request->info.rq); /* the failed request */ 115 break; 116 117 /* 118 * Write the config to disk. We could end up with 119 * quite a few of these in a row. Only honour the 120 * last one 121 */ 122 case daemonrq_saveconfig: 123 if ((daemonq == NULL) /* no more requests */ 124 ||(daemonq->type != daemonrq_saveconfig)) { /* or the next isn't the same */ 125 if (((daemon_options & daemon_noupdate) == 0) /* we're allowed to do it */ 126 &&((vinum_conf.flags & VF_READING_CONFIG) == 0)) { /* and we're not building the config now */ 127 /* 128 * We obviously don't want to save a 129 * partial configuration. Less obviously, 130 * we don't need to do anything if we're 131 * asked to write the config when we're 132 * building it up, because we save it at 133 * the end. 134 */ 135 if (daemon_options & daemon_verbose) 136 log(LOG_INFO, "vinum: saving config\n"); 137 daemon_save_config(); /* save it */ 138 } 139 } 140 break; 141 142 case daemonrq_return: /* been told to stop */ 143 if (daemon_options & daemon_verbose) 144 log(LOG_INFO, "vinum: stopping\n"); 145 daemon_options |= daemon_stopped; /* note that we've stopped */ 146 Free(request); 147 while (daemonq != NULL) { /* backed up requests, */ 148 request = daemonq; /* get the request */ 149 daemonq = daemonq->next; /* and detach it */ 150 Free(request); /* then free it */ 151 } 152 wakeup(&vinumclose); /* and wake any waiting vinum(8)s */ 153 return; 154 155 case daemonrq_ping: /* tell the caller we're here */ 156 if (daemon_options & daemon_verbose) 157 log(LOG_INFO, "vinum: ping reply\n"); 158 wakeup(&vinum_finddaemon); /* wake up the caller */ 159 break; 160 161 case daemonrq_closedrive: /* close a drive */ 162 close_drive(request->info.drive); /* do it */ 163 break; 164 165 case daemonrq_init: /* initialize a plex */ 166 /* XXX */ 167 case daemonrq_revive: /* revive a subdisk */ 168 /* XXX */ 169 /* FALLTHROUGH */ 170 default: 171 log(LOG_WARNING, "Invalid request\n"); 172 break; 173 } 174 if (request->privateinuse) /* one of ours, */ 175 request->privateinuse = 0; /* no longer in use */ 176 else 177 Free(request); /* return it */ 178 } 179 } 180 } 181 182 /* 183 * Recover a failed I/O operation. 184 * 185 * The correct way to do this is to examine the request and determine 186 * how to recover each individual failure. In the case of a write, 187 * this could be as simple as doing nothing: the defective drives may 188 * already be down, and there may be nothing else to do. In case of 189 * a read, it will be necessary to retry if there are alternative 190 * copies of the data. 191 * 192 * The easy way (here) is just to reissue the request. This will take 193 * a little longer, but nothing like as long as the failure will have 194 * taken. 195 * 196 */ 197 void 198 recover_io(struct request *rq) 199 { 200 /* 201 * This should read: 202 * 203 * vinumstrategy(rq->bio); 204 * 205 * Negotiate with phk to get it fixed. 206 * Reissue the command. 207 */ 208 dev_dstrategy((cdev_t)rq->bio->bio_driver_info, rq->bio); 209 } 210 211 /* Functions called to interface with the daemon */ 212 213 /* queue a request for the daemon */ 214 void 215 queue_daemon_request(enum daemonrq type, union daemoninfo info) 216 { 217 struct daemonq *qelt = (struct daemonq *) Malloc(sizeof(struct daemonq)); 218 219 if (qelt == NULL) { /* malloc failed, we're prepared for that */ 220 /* 221 * Take one of our spares. Give up if it's still in use; the only 222 * message we're likely to get here is a 'drive failed' message, 223 * and that'll come by again if we miss it. 224 */ 225 if (intqp->privateinuse) /* still in use? */ 226 return; /* yes, give up */ 227 qelt = intqp++; 228 if (intqp == &intq[INTQSIZE]) /* got to the end, */ 229 intqp = intq; /* wrap around */ 230 qelt->privateinuse = 1; /* it's ours, and it's in use */ 231 } else 232 qelt->privateinuse = 0; 233 234 qelt->next = NULL; /* end of the chain */ 235 qelt->type = type; 236 qelt->info = info; 237 crit_enter(); 238 if (daemonq) { /* something queued already */ 239 dqend->next = qelt; 240 dqend = qelt; 241 } else { /* queue is empty, */ 242 daemonq = qelt; /* this is the whole queue */ 243 dqend = qelt; 244 } 245 crit_exit(); 246 wakeup(&vinum_daemon); /* and give the daemon a kick */ 247 } 248 249 /* 250 * see if the daemon is running. Return 0 (no error) 251 * if it is, ESRCH otherwise 252 */ 253 int 254 vinum_finddaemon(void) 255 { 256 union daemoninfo di = { .nothing = 0 }; 257 int result; 258 259 if (daemonpid != 0) { /* we think we have a daemon, */ 260 queue_daemon_request(daemonrq_ping, di); /* queue a ping */ 261 result = tsleep(&vinum_finddaemon, 0, "reap", 2 * hz); 262 if (result == 0) /* yup, the daemon's up and running */ 263 return 0; 264 } 265 /* no daemon, or we couldn't talk to it: start it */ 266 vinum_daemon(); /* start the daemon */ 267 return 0; 268 } 269 270 int 271 vinum_setdaemonopts(int options) 272 { 273 daemon_options = options; 274 return 0; 275 } 276