Re: [GIT PULL] overlayfs update for 4.18

[Christoph Hellwig]

On Sat, Jun 09, 2018 at 02:42:20PM -0700, Linus Torvalds wrote:
> And Christoph's copmmentary isn't really helping the situation.
> Christoph, I haven't seen the NAK history, can you elaborate?

Most of the bits just need a bit of refinement I think, instead of
being forced through the overlayfs tree and are generally fine.

The pre_mmap hook I think is a clear no-go.  We've had this tried
multiple times and always rejected it.  Unlike previous uses the
overlayfs use isn't outright broken, but still questionalable
as it will still lead to a copyup that "leaks" if the actual mmap
wasn't successfull.  The whole discussion of how mmap happens,
how we deal with mmap_sem and failures needs a broader discussion
with all MM and VFS folks first.