ext4: test for inline data + DAX corruption

Add a regression test for the following kernel commit:

  ext4: prevent data corruption with inline data + DAX

The test passes either if we don't encounter corruption, or if
mounting with DAX + inline data fails.  The latter is the way that
we prevent this issue in the kernel.

[eguan: add 'dax' group]

Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: Eryu Guan <eguan@redhat.com>
Signed-off-by: Eryu Guan <eguan@redhat.com>
6 files changed