xfs_quota_reserve_blkres
error = xfs_quota_reserve_blkres(ip, alen);
error = xfs_quota_reserve_blkres(ip, count_fsb);
int xfs_quota_reserve_blkres(struct xfs_inode *ip, int64_t blocks);
xfs_quota_reserve_blkres(ip, -(int64_t)blocks);