227 lines
7.3 KiB
C
227 lines
7.3 KiB
C
/* daemon.c: kernel part of Vinum daemon */
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/*-
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* Copyright (c) 1997, 1998
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* Nan Yang Computer Services Limited. All rights reserved.
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*
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* This software is distributed under the so-called ``Berkeley
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* License'':
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by Nan Yang Computer
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* Services Limited.
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* 4. Neither the name of the Company nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* This software is provided ``as is'', and any express or implied
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* warranties, including, but not limited to, the implied warranties of
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* merchantability and fitness for a particular purpose are disclaimed.
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* In no event shall the company or contributors be liable for any
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* direct, indirect, incidental, special, exemplary, or consequential
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* damages (including, but not limited to, procurement of substitute
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* goods or services; loss of use, data, or profits; or business
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* interruption) however caused and on any theory of liability, whether
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* in contract, strict liability, or tort (including negligence or
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* otherwise) arising in any way out of the use of this software, even if
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* advised of the possibility of such damage.
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*
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* $Id: vinumdaemon.c,v 1.3 1999/01/18 04:32:50 grog Exp grog $
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*/
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#define REALLYKERNEL
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#include <dev/vinum/vinumhdr.h>
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#include <dev/vinum/request.h>
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#ifdef VINUMDEBUG
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#include <sys/reboot.h>
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#endif
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/* declarations */
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void recover_io(struct request *rq);
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struct daemonq *daemonq; /* daemon's work queue */
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struct daemonq *dqend; /* and the end of the queue */
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int daemon_options = 0; /* options */
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int daemonpid; /* PID of daemon */
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void
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vinum_daemon(void)
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{
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struct daemonq *request;
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int s;
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daemon_save_config(); /* start by saving the configuration */
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daemonpid = curproc->p_pid; /* mark our territory */
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while (1) {
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tsleep(&vinum_daemon, PRIBIO, "vinum", 0); /* wait for something to happen */
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/*
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* It's conceivable that, as the result of an
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* I/O error, we'll be out of action long
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* enough that another daemon gets started.
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* That's OK, just give up gracefully.
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*/
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if (curproc->p_pid != daemonpid) { /* we've been ousted in our sleep */
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if (daemon_options & daemon_verbose)
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log(LOG_INFO, "vinumd: abdicating\n");
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return;
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}
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while (daemonq != NULL) { /* we have work to do, */
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s = splhigh(); /* don't get interrupted here */
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request = daemonq; /* get the request */
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daemonq = daemonq->next; /* and detach it */
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if (daemonq == NULL) /* got to the end, */
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dqend = NULL; /* no end any more */
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splx(s);
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switch (request->type) {
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/*
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* We had an I/O error on a request. Go through the
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* request and try to salvage it
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*/
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case daemonrq_ioerror:
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if (daemon_options & daemon_verbose) {
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struct request *rq = request->info.rq;
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log(LOG_WARNING,
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"vinumd: recovering I/O request: %x\n%s dev 0x%x, offset 0x%x, length %ld\n",
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(u_int) rq,
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rq->bp->b_flags & B_READ ? "Read" : "Write",
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rq->bp->b_dev,
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rq->bp->b_blkno,
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rq->bp->b_bcount);
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}
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recover_io(request->info.rq); /* the failed request */
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break;
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/*
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* Write the config to disk. We could end up with
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* quite a few of these in a row. Only honour the
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* last one
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*/
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case daemonrq_saveconfig:
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if ((daemonq == NULL) /* no more requests */
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||(daemonq->type != daemonrq_saveconfig)) { /* or the next isn't the same */
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if (((daemon_options & daemon_noupdate) == 0) /* we're allowed to do it */
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&&((vinum_conf.flags & VF_READING_CONFIG) == 0)) { /* and we're not building the config now */
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/*
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* We obviously don't want to save a
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* partial configuration. Less obviously,
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* we don't need to do anything if we're
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* asked to write the config when we're
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* building it up, because we save it at
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* the end.
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*/
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if (daemon_options & daemon_verbose)
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log(LOG_INFO, "vinumd: saving config\n");
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daemon_save_config(); /* save it */
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}
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}
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break;
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case daemonrq_return: /* been told to stop */
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if (daemon_options & daemon_verbose)
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log(LOG_INFO, "vinumd: stopping\n");
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daemon_options |= daemon_stopped; /* note that we've stopped */
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return;
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case daemonrq_ping: /* tell the caller we're here */
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if (daemon_options & daemon_verbose)
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log(LOG_INFO, "vinumd: ping reply\n");
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wakeup(&vinum_finddaemon); /* wake up the caller */
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break;
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case daemonrq_init: /* initialize a plex */
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/* XXX */
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case daemonrq_revive: /* revive a subdisk */
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/* XXX */
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default:
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log(LOG_WARNING, "Invalid request\n");
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break;
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}
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Free(request);
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}
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}
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}
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/*
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* Recover a failed I/O operation.
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*
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* The correct way to do this is to examine the request and determine
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* how to recover each individual failure. In the case of a write,
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* this could be as simple as doing nothing: the defective drives may
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* already be down, and there may be nothing else to do. In case of
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* a read, it will be necessary to retry if there are alternative
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* copies of the data.
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*
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* The easy way (here) is just to reissue the request. This will take
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* a little longer, but nothing like as long as the failure will have
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* taken.
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*
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*/
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void
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recover_io(struct request *rq)
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{
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vinumstrategy(rq->bp); /* reissue the command */
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}
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/* Functions called to interface with the daemon */
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/* queue a request for the daemon */
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void
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queue_daemon_request(enum daemonrq type, union daemoninfo info)
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{
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int s;
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struct daemonq *qelt = (struct daemonq *) Malloc(sizeof(struct daemonq));
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qelt->next = NULL; /* end of the chain */
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qelt->type = type;
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qelt->info = info;
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s = splhigh();
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if (daemonq) { /* something queued already */
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dqend->next = qelt;
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dqend = qelt;
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} else { /* queue is empty, */
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daemonq = qelt; /* this is the whole queue */
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dqend = qelt;
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}
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splx(s);
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wakeup(&vinum_daemon); /* and give the d<>mon a kick */
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}
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/*
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* see if the daemon is running. Return 0 (no error)
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* if it is, ESRCH otherwise
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*/
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int
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vinum_finddaemon()
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{
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int result;
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if (daemonpid != 0) { /* we think we have a daemon, */
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queue_daemon_request(daemonrq_ping, (union daemoninfo) NULL); /* queue a ping */
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result = tsleep(&vinum_finddaemon, PUSER, "reap", 2 * hz);
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if (result == 0) /* yup, the daemon's up and running */
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return 0;
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}
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/* no daemon, or we couldn't talk to it: start it */
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vinum_daemon(); /* start the daemon */
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return 0;
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}
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int
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vinum_setdaemonopts(int options)
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{
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daemon_options = options;
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return 0;
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}
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