Re: [PATCH v5 1/2] Return bytes transferred for partial direct I/O

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

On Fri, Jan 19, 2018 at 02:59:51PM +1100, Dave Chinner wrote:
> On Fri, Jan 19, 2018 at 02:13:53AM +0000, Al Viro wrote:
> > On Thu, Jan 18, 2018 at 06:57:40PM -0600, Goldwyn Rodrigues wrote:
> > > From: Goldwyn Rodrigues <rgoldwyn@suse.com>
> > > 
> > > In case direct I/O encounters an error midway, it returns the error.
> > > Instead it should be returning the number of bytes transferred so far.
> > > 
> > > Test case for filesystems (with ENOSPC):
> > > 1. Create an almost full filesystem
> > > 2. Create a file, say /mnt/lastfile, until the filesystem is full.
> > > 3. Direct write() with count > sizeof /mnt/lastfile.
> > > 
> > > Result: write() returns -ENOSPC. However, file content has data written
> > > in step 3.
> > > 
> > > This fixes fstest generic/472.
> > 
> > OK...  I can live with that.  What about the XFS side?  It should be
> > a prereq, to avoid bisection hazard; I can throw both into vfs.git,
> > if XFS folks are OK with that.  Objections?
> 
> Going through the VFS tree seesm the best approach to me - it's a
> trivial change. I'm sure Darrick will shout if it's going to be a
> problem, though.

vfs.git is fine, though the second patch to remove the xfs assert should
go first, as Al points out.

For both patches,
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>

--D

> 
> Cheers,
> 
> Dave.
> -- 
> Dave Chinner
> david@fromorbit.com