xfs: remove suport for filesystems without unwritten extent flag
Source kernel commit:
daa79baefc47293c753fed191d722f7ef605a303
The option to enable unwritten extents was made default in 2003,
removed from mkfs in 2007, and cannot be disabled in v5. We also
rely on it for a lot of common functionality, so filesystems without
it will run a completely untested and buggy code path. Enabling the
support also is a simple bit flip using xfs_db, so legacy file
systems can still be brought forward.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Signed-off-by: Eric Sandeen <sandeen@sandeen.net>