Implement stacked fadvise to fix syscalls readahead(2) and fadvise64(2)
on an overlayfs file.
Suggested-by: Miklos Szeredi <mszeredi@redhat.com>
Fixes: d1d04ef8 ("ovl: stack file ops")
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>