Comment 10 for bug 1293549

A naieve test of aufs directly shows that chown and chmod do cause a copy up of the underlying files as expected.

In the read only layer before chmod/chown:

  drwxrwxr-x 2 apw apw 4096 Mar 18 09:16 D1
  drwxrwxr-x 2 apw apw 4096 Mar 18 09:16 D2
  drwxrwxr-x 2 apw apw 4096 Mar 18 09:16 D3

In the mount after:

  drwxrwxr-x 2 sbuild sbuild 4096 Mar 18 09:16 D1
  drwxrwxrwx 2 apw apw 4096 Mar 18 09:16 D2
  drwxrwxrwx 2 apw apw 4096 Mar 18 09:16 D3

The underlying permissions remain unchanged after these operations. This all seems semantically correct.

I need a description of how we are using aufs in these this scenario (in comment #2), for instance are we modifing the actual underlying files while mounted which would be a no-no.