/*
* Allocate a block in a cylinder group.
*
* This algorithm implements the following policy:
* 1) allocate the requested block.
* 2) allocate a rotationally optimal block in the same cylinder.
* 3) allocate the next available block on the block rotor for the
* specified cylinder group.
* Note that this routine only allocates fs_bsize blocks; these
* blocks may be fragmented by the routine that allocates them.
*/
static daddr_t
ffs_alloccgblk(struct inode *ip, struct buf *bp, daddr_t bpref)
{
struct cg *cgp;
daddr_t blkno;
int32_t bno;
struct fs *fs = ip->i_fs;
const int needswap = UFS_FSNEEDSWAP(fs);
u_int8_t *blksfree;
cgp = (struct cg *)bp->b_data;
blksfree = cg_blksfree(cgp, needswap);
if (bpref == 0 || dtog(fs, bpref) != ufs_rw32(cgp->cg_cgx, needswap)) {
bpref = ufs_rw32(cgp->cg_rotor, needswap);
} else {
bpref = ffs_blknum(fs, bpref);
bno = dtogd(fs, bpref);
/*
* if the requested block is available, use it
*/
if (ffs_isblock(fs, blksfree, ffs_fragstoblks(fs, bno)))
goto gotit;
}
/*
* Take the next available one in this cylinder group.
*/
bno = ffs_mapsearch(fs, cgp, bpref, (int)fs->fs_frag);
if (bno < 0)
return (0);
cgp->cg_rotor = ufs_rw32(bno, needswap);
gotit:
blkno = ffs_fragstoblks(fs, bno);
ffs_clrblock(fs, blksfree, (long)blkno);
ffs_clusteracct(fs, cgp, blkno, -1);
ufs_add32(cgp->cg_cs.cs_nbfree, -1, needswap);
fs->fs_cstotal.cs_nbfree--;
fs->fs_cs(fs, ufs_rw32(cgp->cg_cgx, needswap)).cs_nbfree--;
fs->fs_fmod = 1;
blkno = ufs_rw32(cgp->cg_cgx, needswap) * fs->fs_fpg + bno;
return (blkno);
}
ufs2_daddr_t
cgballoc(struct uufsd *disk)
{
u_int8_t *blksfree;
struct cg *cgp;
struct fs *fs;
long bno;
fs = &disk->d_fs;
cgp = &disk->d_cg;
blksfree = cg_blksfree(cgp);
for (bno = 0; bno < fs->fs_fpg / fs->fs_frag; bno++)
if (ffs_isblock(fs, blksfree, bno))
goto gotit;
return (0);
gotit:
fs->fs_cs(fs, cgp->cg_cgx).cs_nbfree--;
ffs_clrblock(fs, blksfree, (long)bno);
ffs_clusteracct(fs, cgp, bno, -1);
cgp->cg_cs.cs_nbfree--;
fs->fs_cstotal.cs_nbfree--;
fs->fs_fmod = 1;
return (cgbase(fs, cgp->cg_cgx) + blkstofrags(fs, bno));
}
