Re: [atomic-devel] Fedora 26 change: using overlayfs as default

[Vivek Goyal <vgoyal redhat com>]

On Thu, Dec 15, 2016 at 01:30:21PM -0500, Jonathan Lebon wrote:
> The Docker docs also has a breakdown of incompatibilities:
> 
> https://docs.docker.com/engine/userguide/storagedriver/overlayfs-driver/#/overlayfs-compatibility
> 
> Notably, there's the open(2) issue that has already been
> mentioned. The second issue is that rename(2) can fail if
> trying to move a dir across the lower and upper dirs:
> 
> $ mkdir lower upper work merged
> $ mkdir lower/dir
> $ sudo mount -t overlay overlay \
>     -olowerdir=$PWD/lower,upperdir=$PWD/upper,workdir=$PWD/work \
>     merged
> $ python -c 'import os; os.rename("merged/dir", "merged/dir2")'
> Traceback (most recent call last):
>     File "<string>", line 1, in <module>
>     OSError: [Errno 18] Invalid cross-device link
> 
> So you have to watch for EXDEV and fall back on copying.

I think renaming of directories from lower to upper has been taken care of
by miklos in his tree and it should show up in 4.10 kernel.

https://git.kernel.org/cgit/linux/kernel/git/mszeredi/vfs.git/commit/?h=overlayfs-linus&id=79a95dbf629f39b0379cde43ac50351567ffa50e

Vivek