On 19:08 22/07, Avi Kivity wrote:
>
> On 13/12/2018 13.53, Goldwyn Rodrigues wrote:
> > For AIO+DIO with RWF_NOWAIT, if the block layer does not support REQ_NOWAIT,
> > it returns EIO. Return EOPNOTSUPP to represent the correct error code.
> >
> > Signed-off-by: Goldwyn Rodrigues <rgoldwyn@xxxxxxxx>
> > ---
> > fs/direct-io.c | 11 +++++++----
> > 1 file changed, 7 insertions(+), 4 deletions(-)
> >
> > diff --git a/fs/direct-io.c b/fs/direct-io.c
> > index 41a0e97252ae..77adf33916b8 100644
> > --- a/fs/direct-io.c
> > +++ b/fs/direct-io.c
> > @@ -542,10 +542,13 @@ static blk_status_t dio_bio_complete(struct dio *dio, struct bio *bio)
> > blk_status_t err = bio->bi_status;
> > if (err) {
> > - if (err == BLK_STS_AGAIN && (bio->bi_opf & REQ_NOWAIT))
> > - dio->io_error = -EAGAIN;
> > - else
> > - dio->io_error = -EIO;
> > + dio->io_error = -EIO;
> > + if (bio->bi_opf & REQ_NOWAIT) {
> > + if (err == BLK_STS_AGAIN)
> > + dio->io_error = -EAGAIN;
> > + else if (err == BLK_STS_NOTSUPP)
> > + dio->io_error = -EOPNOTSUPP;
> > + }
> > }
> > if (dio->is_async && dio->op == REQ_OP_READ && dio->should_dirty) {
>
>
> In the end, did this or some alternative get applied? I'd like to enable
> RWF_NOWAIT support, but EIO scares me and my application.
>
No, it was not. There were lot of objections to return error from the
block layer for a filesystem nowait request.
--
Goldwyn
