ext4: Fix data exposure after failed AIO DIO

ext4: Fix data exposure after failed AIO DIO

When AIO DIO fails e.g. due to IO error, we must not convert unwritten
extents as that will expose uninitialized data. Handle this case
by clearing unwritten flag from io_end in case of error and thus
preventing extent conversion.

Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Chinner <david@fromorbit.com>
(cherry-picked commit from 74c66bcb7eda551f3b8588659c58fe29184af903)

Orabug: 24393811

Signed-off-by: Ashok Vairavan <ashok.vairavan@oracle.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>