v7fs_datablock_size_change
int v7fs_datablock_size_change(struct v7fs_self *, size_t, struct v7fs_inode *);
error = v7fs_datablock_size_change(fs, 0, &inode);
v7fs_datablock_size_change(fs, 0, inode);
error = v7fs_datablock_size_change(fs, vap->va_size, inode);