Via unshare, copy up dir from lower dir then remove
them in another unshared namespace.
This would fail before v4.7 kernel with EPERM.
Kernel commit 3fe6e52f
ovl: override creds with the ones from the superblock mounter
fixed this issue, with this reproducer provided. Original
reproducer was written by commit author:
Antonio Murdaca <amurdaca@redhat.com>
Signed-off-by: Xiong Zhou <xzhou@redhat.com>
Reviewed-by: Eryu Guan <eguan@redhat.com>
Signed-off-by: Eryu Guan <eguan@redhat.com>
Xiong Zhou