fuse_inval_buf_range
err = fuse_inval_buf_range(outvp, outfilesize, *ap->a_outoffp,
err = fuse_inval_buf_range(vp, filesize, start,
err = fuse_inval_buf_range(vp, filesize, *offset, *offset + *len, 0);
err = fuse_inval_buf_range(vp, filesize, *offset, *offset + *len,