Re: [PATCH 5/6] aio: implement IOCB_CMD_FSYNC and IOCB_CMD_FDSYNC

Al Viro
2018-04-06T02:59:52Z

On Wed, Mar 28, 2018 at 09:26:38AM +0200, Christoph Hellwig wrote:
> +static int aio_fsync(struct fsync_iocb *req, struct iocb *iocb, bool datasync)
> +{
> + int ret;
> +
> + if (iocb->aio_buf)
> + return -EINVAL;
> + if (iocb->aio_offset || iocb->aio_nbytes || iocb->aio_rw_flags)
> + return -EINVAL;
> +
> + req->file = fget(iocb->aio_fildes);
> + if (unlikely(!req->file))
> + return -EBADF;
> +
> + ret = -EINVAL;
> + if (!req->file->f_op->fsync)
> + goto out_fput;
> +
> + req->datasync = datasync;
> + INIT_WORK(&req->work, aio_fsync_work);
> + schedule_work(&req->work);
> + return -EIOCBQUEUED;
> +out_fput:
> + if (unlikely(ret && ret != -EIOCBQUEUED))

Really? The only way to get there is if we got NULL ->f_op->fsync.
So this "if (unlikely(...))" is actually if (true) and I'm not
sure we want that separated anyway - simply

if (unlikely(!req->file->f_op->fsync)) {
fput(req->file);
return -EINVAL;
}

> + fput(req->file);

> + return ret;
> +}