btrfs: regression test for btrfs buffered read's repair

This case tests whether buffered read can repair the bad copy if we
have a good copy.

Commit 20a7db8ab3f2 ("btrfs: add dummy callback for readpage_io_failed
and drop checks") introduced the regression.

The upstream fix is commit 9d0d1c8b1c9d ("Btrfs: bring back repair
during read")

Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Reviewed-by: Eryu Guan <eguan@redhat.com>
Reviewed-by: Filipe Manana <fdmanana@gmail.com>
Signed-off-by: Eryu Guan <eguan@redhat.com>
3 files changed