[CRIU] [PATCH] zdtm: add ability to execute tests on aufs

[Pavel Emelyanov]

On 09/08/2014 10:36 AM, Saied Kazemi wrote:
> Here is an explanation of the problem.  As you know, the AUFS implementation in the kernel has a bug.  Specifically, by pointing inside AUFS branches, the file descriptors of links in /proc/<pid>/map_files create two problems (these file descriptors are saved by ma_get_mapfile() in vma->vm_file_fd):
> 
> 1. When doing readlink() on them, the path inside the branch is not accessible in the mount namespace.
> 
> 2. When reading their /proc/<pid>/fdinfo, the mnt_id value corresponds to a mountpoint that is not visible in the mount namespace.
> 
> The patch that we applied earlier addressed issue 1 above.  Attached is a patch for issue 2 if we need a quick workaround 
> but I would like a better solution.  The patch has a special provision for AUFS to return the root mountpoint if mnt_id cannot be found.
> 
> What do you guys think?

I'm not sure this is the correct way to go. With this we can
erroneously succeed the situation when a file is really opened
outside of the container and is having an "invisible" mnt_id.

Thanks,
Pavel