Re: [PATCH 01/25] xfs: remove the first extent special case in xfs_bmap_add_extent

[Christoph Hellwig <hch@xxxxxxxxxxxxx>]

On Fri, Sep 02, 2011 at 05:22:56PM -0500, Alex Elder wrote:
> On Wed, 2011-08-24 at 02:04 -0400, Christoph Hellwig wrote:
> > Both xfs_bmap_add_extent_hole_delay and xfs_bmap_add_extent_hole_real
> > already contain code to handle the case where there is no extent to
> > merge with, which is effectively the same as the code duplicated here.
> > 
> > Signed-off-by: Christoph Hellwig <hch@xxxxxx>
> 
> It looks like an attribute fork will never get a delayed
> allocation extent assigned to it.  At least I assume so,
> because xfs_bmap_add_extent_hole_delay() only ever works
> on the data fork.  (I didn't know that.)

Yes, we only use delayed allocation for file data.  The same is
also true for unwritten extents.