On Fri, Feb 8, 2019 at 6:34 PM Jens Axboe <axboe@xxxxxxxxx> wrote:
> From: Christoph Hellwig <hch@xxxxxx>
>
> Add a new fsync opcode, which either syncs a range if one is passed,
> or the whole file if the offset and length fields are both cleared
> to zero. A flag is provided to use fdatasync semantics, that is only
> force out metadata which is required to retrieve the file data, but
> not others like metadata.
>
> Signed-off-by: Christoph Hellwig <hch@xxxxxx>
> Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
> ---
[...]
> +static int io_fsync(struct io_kiocb *req, const struct io_uring_sqe *sqe,
> + bool force_nonblock)
> +{
> + struct io_ring_ctx *ctx = req->ctx;
> + loff_t sqe_off = READ_ONCE(sqe->off);
> + loff_t sqe_len = READ_ONCE(sqe->len);
> + loff_t end = sqe_off + sqe_len;
> + unsigned fsync_flags;
> + struct file *file;
> + int ret, fd;
> +
> + /* fsync always requires a blocking context */
> + if (force_nonblock)
> + return -EAGAIN;
> +
> + if (unlikely(sqe->addr || sqe->ioprio))
> + return -EINVAL;
> +
> + fsync_flags = READ_ONCE(sqe->fsync_flags);
> + if (unlikely(fsync_flags & ~IORING_FSYNC_DATASYNC))
> + return -EINVAL;
> +
> + fd = READ_ONCE(sqe->fd);
> + file = fget(fd);
This always runs on the workqueue, right? Is it possible to call
fget() on a workqueue?
> + if (unlikely(!file))
> + return -EBADF;
> +
> + ret = vfs_fsync_range(file, sqe_off, end > 0 ? end : LLONG_MAX,
> + fsync_flags & IORING_FSYNC_DATASYNC);
> +
> + fput(file);
> + io_cqring_add_event(ctx, sqe->user_data, ret, 0);
> + io_free_req(req);
> + return 0;
> +}
