Re: [RFC 0/7] [RFC] cramfs: fake write support

[Arnd Bergmann <arnd@arndb.de>]

On Monday 02 June 2008, hooanon05@yahoo.co.jp wrote:
> I don't want you to call aufs users crazy who are using such policies.
> By the way, how do you think link(2) or rename(2)? When the source file
> exists on the lower writable branch, do you think copy-up is the best
> way? Or do you think all lower branches should be readonly?
> There is an exception in aufs's branch-select policy. That is
> link/rename case. When the source file exists on a writable branch, aufs
> tries link/rename it on that branch in every policy. Do you think it
> best to do it on the top branch only?

Yes, I tend to consider the union case identical to the cross-mount
move or link, so I'd expect the kernel to return errno=EXDEV and user
space to handle this by doing the appropriate copy/unlink as it does
for other cases already.

	Arnd <><