/*
* place the specified disk block
* back on the free list of the
* specified device.
*/
void free(dev_t dev, daddr_t bno) {
struct filsys *fp;
struct buf *bp;
if (debugFree) {
printf("----- free dev = 0x%08X, bno = 0x%08X -----\n", dev, bno);
}
fp = getfs(dev);
fp->s_fmod = 1;
while(fp->s_flock)
sleep((caddr_t)&fp->s_flock, PINOD);
if (badblock(fp, bno, dev))
return;
if(fp->s_nfree <= 0) {
fp->s_nfree = 1;
fp->s_free[0] = 0;
}
if(fp->s_nfree >= NICFREE) {
fp->s_flock++;
bp = getblk(dev, bno);
((FBLKP)(bp->b_un.b_addr))->df_nfree = fp->s_nfree;
bcopy((caddr_t)fp->s_free,
(caddr_t)((FBLKP)(bp->b_un.b_addr))->df_free,
sizeof(fp->s_free));
fp->s_nfree = 0;
bwrite(bp);
fp->s_flock = 0;
wakeup((caddr_t)&fp->s_flock);
}
fp->s_free[fp->s_nfree++] = bno;
fp->s_fmod = 1;
}
/*
* place the specified disk block
* back on the free list of the
* specified device.
*/
free(dev, bno)
{
register *fp, *bp, *ip;
fp = getfs(dev);
fp->s_fmod = 1;
while(fp->s_flock)
sleep(&fp->s_flock, PINOD);
if (badblock(fp, bno, dev))
return;
if(fp->s_nfree <= 0) {
fp->s_nfree = 1;
fp->s_free[0] = 0;
}
if(fp->s_nfree >= 100) {
fp->s_flock++;
bp = getblk(dev, bno);
ip = bp->b_addr;
*ip++ = fp->s_nfree;
bcopy(fp->s_free, ip, 100);
fp->s_nfree = 0;
bwrite(bp);
fp->s_flock = 0;
wakeup(&fp->s_flock);
}
fp->s_free[fp->s_nfree++] = bno;
fp->s_fmod = 1;
}
/*
* alloc will obtain the next available
* free disk block from the free list of
* the specified device.
* The super block has up to NICFREE remembered
* free blocks; the last of these is read to
* obtain NICFREE more . . .
*
* no space on dev x/y -- when
* the free list is exhausted.
*/
struct buf *alloc(dev_t dev) {
daddr_t bno;
struct filsys *fp;
struct buf *bp;
if (debugAlloc) {
printf("----- alloc dev = 0x%08X -----\n", dev);
}
fp = getfs(dev);
while(fp->s_flock)
sleep((caddr_t)&fp->s_flock, PINOD);
do {
if(fp->s_nfree <= 0)
goto nospace;
if (fp->s_nfree > NICFREE) {
prdev("bad free count", dev);
goto nospace;
}
bno = fp->s_free[--fp->s_nfree];
if(bno == 0)
goto nospace;
} while (badblock(fp, bno, dev));
if(fp->s_nfree <= 0) {
fp->s_flock++;
bp = bread(dev, bno);
if ((bp->b_flags&B_ERROR) == 0) {
fp->s_nfree = ((FBLKP)(bp->b_un.b_addr))->df_nfree;
bcopy((caddr_t)((FBLKP)(bp->b_un.b_addr))->df_free,
(caddr_t)fp->s_free, sizeof(fp->s_free));
}
brelse(bp);
fp->s_flock = 0;
wakeup((caddr_t)&fp->s_flock);
if (fp->s_nfree <=0)
goto nospace;
}
bp = getblk(dev, bno);
clrbuf(bp);
fp->s_fmod = 1;
if (debugAlloc) {
printf(" alloc = 0x%08X\n", bp->b_blkno);
}
return(bp);
nospace:
fp->s_nfree = 0;
prdev("no space", dev);
u.u_error = ENOSPC;
return(NULL);
}
