sys/dev/raid/vinum/vinumdaemon.c

   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 }