tree a85c276c7ba414ecc65a93488dcb2ef7972779c0
parent ab9a79b9669c28734a69fa9384df6fb93152e53a
author Al Viro <viro@zeniv.linux.org.uk> 1274072386 -0400
committer Al Viro <viro@zeniv.linux.org.uk> 1274481087 -0400

Ban ecryptfs over ecryptfs

This is a seriously simplified patch from Eric Sandeen; copy of
rationale follows:
===
  mounting stacked ecryptfs on ecryptfs has been shown to lead to bugs
  in testing.  For crypto info in xattr, there is no mechanism for handling
  this at all, and for normal file headers, we run into other trouble:

  BUG: unable to handle kernel NULL pointer dereference at 0000000000000008
  IP: [<ffffffffa015b0b3>] ecryptfs_d_revalidate+0x43/0xa0 [ecryptfs]
  ...

  There doesn't seem to be any good usecase for this, so I'd suggest just
  disallowing the configuration.

  Based on a patch originally, I believe, from Mike Halcrow.
===

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>