271 lines
7.7 KiB
C
271 lines
7.7 KiB
C
/*-
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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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* Parts copyright (c) 1997, 1998 Cybernet Corporation, NetMAX project.
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*
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* Written by Greg Lehey
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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: vinumlock.c,v 1.10 1999/05/15 03:47:45 grog Exp grog $
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*/
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#include <dev/vinum/vinumhdr.h>
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/*
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* Lock routines. Currently, we lock either an individual volume
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* or the global configuration. I don't think tsleep and
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* wakeup are SMP safe. FIXME XXX
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*/
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/* Lock a drive, wait if it's in use */
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#if VINUMDEBUG
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int
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lockdrive(struct drive *drive, char *file, int line)
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#else
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int
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lockdrive(struct drive *drive)
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#endif
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{
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int error;
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/* XXX get rid of drive->flags |= VF_LOCKING; */
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if ((drive->flags & VF_LOCKED) /* it's locked */
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&&(drive->pid == curproc->p_pid)) { /* by us! */
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#ifdef VINUMDEBUG
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log(LOG_WARNING,
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"vinum lockdrive: already locking %s from %s:%d, called from %s:%d\n",
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drive->label.name,
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drive->lockfilename,
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drive->lockline,
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basename(file),
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line);
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#else
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log(LOG_WARNING,
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"vinum lockdrive: already locking %s\n",
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drive->label.name);
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#endif
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return 0;
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}
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while ((drive->flags & VF_LOCKED) != 0) {
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/*
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* There are problems sleeping on a unique identifier,
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* since the drive structure can move, and the unlock
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* function can be called after killing the drive.
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* Solve this by waiting on this function; the number
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* of conflicts is negligible.
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*/
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if ((error = tsleep(&lockdrive,
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PRIBIO | PCATCH,
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"vindrv",
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0)) != 0)
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return error;
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}
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drive->flags |= VF_LOCKED;
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drive->pid = curproc->p_pid; /* it's a panic error if curproc is null */
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#ifdef VINUMDEBUG
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bcopy(basename(file), drive->lockfilename, 15);
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drive->lockfilename[15] = '\0'; /* truncate if necessary */
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drive->lockline = line;
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#endif
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return 0;
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}
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/* Unlock a drive and let the next one at it */
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void
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unlockdrive(struct drive *drive)
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{
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drive->flags &= ~VF_LOCKED;
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/* we don't reset pid: it's of hysterical interest */
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wakeup(&lockdrive);
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}
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/* Lock a volume, wait if it's in use */
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int
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lockvol(struct volume *vol)
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{
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int error;
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while ((vol->flags & VF_LOCKED) != 0) {
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vol->flags |= VF_LOCKING;
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/*
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* It would seem to make more sense to sleep on
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* the address 'vol'. Unfortuntaly we can't
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* guarantee that this address won't change due to
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* table expansion. The address we choose won't change.
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*/
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if ((error = tsleep(&vinum_conf.volume + vol->volno,
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PRIBIO | PCATCH,
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"volock",
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0)) != 0)
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return error;
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}
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vol->flags |= VF_LOCKED;
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return 0;
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}
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/* Unlock a volume and let the next one at it */
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void
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unlockvol(struct volume *vol)
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{
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vol->flags &= ~VF_LOCKED;
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if ((vol->flags & VF_LOCKING) != 0) {
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vol->flags &= ~VF_LOCKING;
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wakeup(&vinum_conf.volume + vol->volno);
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}
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}
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/* Lock a plex, wait if it's in use */
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int
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lockplex(struct plex *plex)
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{
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int error;
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while ((plex->flags & VF_LOCKED) != 0) {
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plex->flags |= VF_LOCKING;
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/*
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* It would seem to make more sense to sleep on
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* the address 'plex'. Unfortunately we can't
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* guarantee that this address won't change due to
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* table expansion. The address we choose won't change.
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*/
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if ((error = tsleep(&vinum_conf.plex + plex->sdnos[0],
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PRIBIO | PCATCH,
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"plexlk",
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0)) != 0)
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return error;
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}
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plex->flags |= VF_LOCKED;
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return 0;
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}
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/* Unlock a plex and let the next one at it */
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void
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unlockplex(struct plex *plex)
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{
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plex->flags &= ~VF_LOCKED;
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if ((plex->flags & VF_LOCKING) != 0) {
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plex->flags &= ~VF_LOCKING;
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wakeup(&vinum_conf.plex + plex->plexno);
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}
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}
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#define LOCK_UNALLOC -1 /* mark unused lock entries */
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/* Lock an address range in a plex, wait if it's in use */
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int
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lockrange(struct plex *plex, off_t first, off_t last)
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{
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int lock;
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int pos = -1; /* place to insert */
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lockplex(plex); /* diddle one at a time */
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if (plex->locks >= plex->alloclocks)
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EXPAND(plex->lock, struct rangelock, plex->alloclocks, INITIAL_LOCKS)
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unlockplex(plex);
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for (;;) {
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lockplex(plex);
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for (lock = 0; lock < plex->locks; lock++) {
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if (plex->lock[lock].first == LOCK_UNALLOC) /* empty place */
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pos = lock; /* a place to put this one */
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else if ((plex->lock[lock].first < last)
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&& (plex->lock[lock].last > first)) { /* overlap, */
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unlockplex(plex);
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tsleep(((caddr_t *) & lockrange) + plex->sdnos[0], PRIBIO | PCATCH, "vrlock", 0);
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break; /* out of the inner level loop */
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}
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}
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if (lock == plex->locks) /* made it to the end, */
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break;
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}
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/*
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* The address range is free, and the plex is locked.
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* Add our lock entry
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*/
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if (pos == -1) { /* no free space, */
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pos = lock; /* put it at the end */
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plex->locks++;
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}
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plex->lock[pos].first = first;
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plex->lock[pos].last = last;
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unlockplex(plex);
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return 0;
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}
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/* Unlock a volume and let the next one at it */
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void
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unlockrange(struct plex *plex, off_t first, off_t last)
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{
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int lock;
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lockplex(plex);
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for (lock = 0; lock < plex->locks; lock++) {
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if ((plex->lock[lock].first == first)
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&& (plex->lock[lock].last == last)) { /* found our lock */
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plex->lock[lock].first = LOCK_UNALLOC; /* not used */
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break; /* out of the inner level loop */
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}
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}
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if (lock == plex->locks) /* made it to the end, */
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panic("vinum: unlock without lock");
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unlockplex(plex);
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}
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/* Get a lock for the global config, wait if it's not available */
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int
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lock_config(void)
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{
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int error;
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while ((vinum_conf.flags & VF_LOCKED) != 0) {
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vinum_conf.flags |= VF_LOCKING;
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if ((error = tsleep(&vinum_conf, PRIBIO | PCATCH, "vincfg", 0)) != 0)
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return error;
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}
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vinum_conf.flags |= VF_LOCKED;
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return 0;
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}
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/* Unlock and wake up any waiters */
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void
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unlock_config(void)
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{
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vinum_conf.flags &= ~VF_LOCKED;
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if ((vinum_conf.flags & VF_LOCKING) != 0) {
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vinum_conf.flags &= ~VF_LOCKING;
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wakeup(&vinum_conf);
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}
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}
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