Merge tag 'fs.idmapped.mount_setattr.v5.13-rc3' of gitolite.kernel.org:pub/scm/linux...

Pull mount_setattr fix from Christian Brauner:
 "This makes an underlying idmapping assumption more explicit.

  We currently don't have any filesystems that support idmapped mounts
  which are mountable inside a user namespace, i.e. where s_user_ns !=
  init_user_ns. That was a deliberate decision for now as userns root
  can just mount the filesystem themselves.

  Express this restriction explicitly and enforce it until there's a
  real use-case for this. This way we can notice it and will have a
  chance to adapt and audit our translation helpers and fstests
  appropriately if we need to support such filesystems"

* tag 'fs.idmapped.mount_setattr.v5.13-rc3' of gitolite.kernel.org:pub/scm/linux/kernel/git/brauner/linux:
  fs/mount_setattr: tighten permission checks