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  * $DragonFly: src/sys/dev/raid/vinum/vinumdaemon.c,v 1.12 2008/06/05 18:06:31 swildner Exp $
  40  */
  41
  42 #include "vinumhdr.h"
  43 #include "request.h"
  44
  45 #ifdef VINUMDEBUG
  46 #include <sys/reboot.h>
  47 #endif
  48
  49 /* declarations */
  50 void recover_io(struct request *rq);
  51
  52 int daemon_options = 0;                                     /* options */
  53 int daemonpid;                                              /* PID of daemon */
  54 struct daemonq *daemonq;                                    /* daemon's work queue */
  55 struct daemonq *dqend;                                      /* and the end of the queue */
  56
  57 /*
  58  * We normally call Malloc to get a queue element.  In interrupt
  59  * context, we can't guarantee that we'll get one, since we're not
  60  * allowed to wait.  If malloc fails, use one of these elements.
  61  */
  62
  63 #define INTQSIZE 4
  64 struct daemonq intq[INTQSIZE];                              /* queue elements for interrupt context */
  65 struct daemonq *intqp;                                      /* and pointer in it */
  66
  67 void
  68 vinum_daemon(void)
  69 {
  70     struct daemonq *request;
  71
  72     curproc->p_flag |= P_SYSTEM;                    /* we're a system process */
  73     daemon_save_config();                                   /* start by saving the configuration */
  74     daemonpid = curproc->p_pid;                             /* mark our territory */
  75     while (1) {
  76         tsleep(&vinum_daemon, 0, "vinum", 0);       /* wait for something to happen */
  77
  78         /*
  79          * It's conceivable that, as the result of an
  80          * I/O error, we'll be out of action long
  81          * enough that another daemon gets started.
  82          * That's OK, just give up gracefully.
  83          */
  84         if (curproc->p_pid != daemonpid) {                  /* we've been ousted in our sleep */
  85             if (daemon_options & daemon_verbose)
  86                 log(LOG_INFO, "vinum: abdicating\n");
  87             return;
  88         }
  89         while (daemonq != NULL) {                           /* we have work to do, */
  90             crit_enter();
  91             request = daemonq;                              /* get the request */
  92             daemonq = daemonq->next;                        /* and detach it */
  93             if (daemonq == NULL)                            /* got to the end, */
  94                 dqend = NULL;                               /* no end any more */
  95             crit_exit();
  96
  97             switch (request->type) {
  98                 /*
  99                  * We had an I/O error on a request.  Go through the
 100                  * request and try to salvage it
 101                  */
 102             case daemonrq_ioerror:
 103                 if (daemon_options & daemon_verbose) {
 104                     struct request *rq = request->info.rq;
 105
 106                     log(LOG_WARNING,
 107                         "vinum: recovering I/O request: %p\n%s dev %d.%d, offset 0x%012llx, length %d\n",
 108                         rq,
 109                         (rq->bio->bio_buf->b_cmd == BUF_CMD_READ) ? "Read" : "Write",
 110                         major((cdev_t)rq->bio->bio_driver_info),
 111                         minor((cdev_t)rq->bio->bio_driver_info),
 112                         (long long)rq->bio->bio_offset,
 113                         rq->bio->bio_buf->b_bcount);
 114                 }
 115                 recover_io(request->info.rq);               /* the failed request */
 116                 break;
 117
 118                 /*
 119                  * Write the config to disk.  We could end up with
 120                  * quite a few of these in a row.  Only honour the
 121                  * last one
 122                  */
 123             case daemonrq_saveconfig:
 124                 if ((daemonq == NULL)                       /* no more requests */
 125                 ||(daemonq->type != daemonrq_saveconfig)) { /* or the next isn't the same */
 126                     if (((daemon_options & daemon_noupdate) == 0) /* we're allowed to do it */
 127                     &&((vinum_conf.flags & VF_READING_CONFIG) == 0)) { /* and we're not building the config now */
 128                         /*
 129                            * We obviously don't want to save a
 130                            * partial configuration.  Less obviously,
 131                            * we don't need to do anything if we're
 132                            * asked to write the config when we're
 133                            * building it up, because we save it at
 134                            * the end.
 135                          */
 136                         if (daemon_options & daemon_verbose)
 137                             log(LOG_INFO, "vinum: saving config\n");
 138                         daemon_save_config();               /* save it */
 139                     }
 140                 }
 141                 break;
 142
 143             case daemonrq_return:                           /* been told to stop */
 144                 if (daemon_options & daemon_verbose)
 145                     log(LOG_INFO, "vinum: stopping\n");
 146                 daemon_options |= daemon_stopped;           /* note that we've stopped */
 147                 Free(request);
 148                 while (daemonq != NULL) {                   /* backed up requests, */
 149                     request = daemonq;                      /* get the request */
 150                     daemonq = daemonq->next;                /* and detach it */
 151                     Free(request);                          /* then free it */
 152                 }
 153                 wakeup(&vinumclose);                        /* and wake any waiting vinum(8)s */
 154                 return;
 155
 156             case daemonrq_ping:                             /* tell the caller we're here */
 157                 if (daemon_options & daemon_verbose)
 158                     log(LOG_INFO, "vinum: ping reply\n");
 159                 wakeup(&vinum_finddaemon);                  /* wake up the caller */
 160                 break;
 161
 162             case daemonrq_closedrive:                       /* close a drive */
 163                 close_drive(request->info.drive);           /* do it */
 164                 break;
 165
 166             case daemonrq_init:                             /* initialize a plex */
 167                 /* XXX */
 168             case daemonrq_revive:                           /* revive a subdisk */
 169                 /* XXX */
 170                 /* FALLTHROUGH */
 171             default:
 172                 log(LOG_WARNING, "Invalid request\n");
 173                 break;
 174             }
 175             if (request->privateinuse)                      /* one of ours, */
 176                 request->privateinuse = 0;                  /* no longer in use */
 177             else
 178                 Free(request);                              /* return it */
 179         }
 180     }
 181 }
 182
 183 /*
 184  * Recover a failed I/O operation.
 185  *
 186  * The correct way to do this is to examine the request and determine
 187  * how to recover each individual failure.  In the case of a write,
 188  * this could be as simple as doing nothing: the defective drives may
 189  * already be down, and there may be nothing else to do.  In case of
 190  * a read, it will be necessary to retry if there are alternative
 191  * copies of the data.
 192  *
 193  * The easy way (here) is just to reissue the request.  This will take
 194  * a little longer, but nothing like as long as the failure will have
 195  * taken.
 196  *
 197  */
 198 void
 199 recover_io(struct request *rq)
 200 {
 201     /*
 202      * This should read:
 203      *
 204      *     vinumstrategy(rq->bio);
 205      *
 206      * Negotiate with phk to get it fixed.
 207      * Reissue the command.
 208      */
 209     dev_dstrategy((cdev_t)rq->bio->bio_driver_info, rq->bio);
 210 }
 211
 212 /* Functions called to interface with the daemon */
 213
 214 /* queue a request for the daemon */
 215 void
 216 queue_daemon_request(enum daemonrq type, union daemoninfo info)
 217 {
 218     struct daemonq *qelt = (struct daemonq *) Malloc(sizeof(struct daemonq));
 219
 220     if (qelt == NULL) {                                     /* malloc failed, we're prepared for that */
 221         /*
 222          * Take one of our spares.  Give up if it's still in use; the only
 223          * message we're likely to get here is a 'drive failed' message,
 224          * and that'll come by again if we miss it.
 225          */
 226         if (intqp->privateinuse)                            /* still in use? */
 227             return;                                         /* yes, give up */
 228         qelt = intqp++;
 229         if (intqp == &intq[INTQSIZE])                       /* got to the end, */
 230             intqp = intq;                                   /* wrap around */
 231         qelt->privateinuse = 1;                             /* it's ours, and it's in use */
 232     } else
 233         qelt->privateinuse = 0;
 234
 235     qelt->next = NULL;                                      /* end of the chain */
 236     qelt->type = type;
 237     qelt->info = info;
 238     crit_enter();
 239     if (daemonq) {                                          /* something queued already */
 240         dqend->next = qelt;
 241         dqend = qelt;
 242     } else {                                                /* queue is empty, */
 243         daemonq = qelt;                                     /* this is the whole queue */
 244         dqend = qelt;
 245     }
 246     crit_exit();
 247     wakeup(&vinum_daemon);                                  /* and give the dæmon a kick */
 248 }
 249
 250 /*
 251  * see if the daemon is running.  Return 0 (no error)
 252  * if it is, ESRCH otherwise
 253  */
 254 int
 255 vinum_finddaemon(void)
 256 {
 257     int result;
 258
 259     if (daemonpid != 0) {                                   /* we think we have a daemon, */
 260         queue_daemon_request(daemonrq_ping, (union daemoninfo) 0); /* 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 }