ffs_isfreeblock
int ffs_isfreeblock(struct fs *, u_char *, ufs1_daddr_t);
if (ffs_isfreeblock(&sblock, blksfree, cgbno))
if (!ffs_isfreeblock(fs, blksfree, fragno)) {
int ffs_isfreeblock(struct fs *, uint8_t *, ufs1_daddr_t);
if (!ffs_isfreeblock(fs, cg_blksfree_swap(cgp, needswap), fragno)) {
int ffs_isfreeblock(struct fs *, u_char *, int32_t);