i_ffs1_size
ip->i_ffs1_size = ip->i_size;
uvm_vnp_setsize(vp, ip->i_ffs1_size);
ip->i_size = ip->i_ffs1_size;
lastlbn = ffs_lblkno(fs, ip->i_ffs1_size);
if (nb != 0 && ip->i_ffs1_size >= ffs_lblktosize(fs, lbn + 1)) {
osize = ffs_fragroundup(fs, ffs_blkoff(fs, ip->i_ffs1_size));
if (ip->i_ffs1_size < ffs_lblktosize(fs, lbn + 1))