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

[Al Viro <viro@ZenIV.linux.org.uk>]

On Thu, Jan 18, 2018 at 10:31:18PM -0800, Darrick J. Wong wrote:
> 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>

Applied; will be in -next tomorrow morning after the tree I'm putting together
gets through local beating.