Re: [PATCH v2] splice: only read in as much information as there is pipe buffer space

["Darrick J. Wong" <darrick.wong@oracle.com>]

On Tue, Sep 17, 2019 at 03:17:22PM +0200, Andreas Grünbacher wrote:
> Am Do., 5. Sept. 2019 um 05:42 Uhr schrieb Darrick J. Wong
> <darrick.wong@oracle.com>:
> > On Fri, Aug 30, 2019 at 02:06:03PM -0700, Darrick J. Wong wrote:
> > > From: Darrick J. Wong <darrick.wong@oracle.com>
> > >
> > > Andreas Grünbacher reports that on the two filesystems that support
> > > iomap directio, it's possible for splice() to return -EAGAIN (instead of
> > > a short splice) if the pipe being written to has less space available in
> > > its pipe buffers than the length supplied by the calling process.
> > >
> > > Months ago we fixed splice_direct_to_actor to clamp the length of the
> > > read request to the size of the splice pipe.  Do the same to do_splice.
> > >
> > > Fixes: 17614445576b6 ("splice: don't read more than available pipe space")
> > > Reported-by: Andreas Grünbacher <andreas.gruenbacher@gmail.com>
> > > Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
> > > ---
> > > v2: tidy up the other call site per Andreas' request
> >
> > Ping?  Anyone want to add a RVB to this?
> 
> You can add the following:
> 
> Reviewed-by: Andreas Grünbacher <agruenba@redhat.com>
> Tested-by: Andreas Grünbacher <agruenba@redhat.com>
> 
> And could you please update the email address in the reported-by tag as well?

Done.

> Is this going to go in via the xfs tree?

I'll let it soak in -next for a few days and send a single-patch pull
request for it.

(I'm sending out pull requests today for the things that have been
ready to go for the last couple of weeks.)

--D

> Thanks,
> Andreas