[PATCH v4 0/2] NFS: Fix interaction between fs_context and user namespaces

[Sargun Dhillon <sargun@sargun.me>]

This is effectively a resend, but re-based atop Anna's current tree. I can
add the samples back in an another patchset.

Right now, it is possible to mount NFS with an non-matching super block
user ns, and NFS sunrpc user ns. This (for the user) results in an awkward
set of interactions if using anything other than auth_null, where the UIDs
being sent to the server are different than the local UIDs being checked.
This can cause "breakage", where if you try to communicate with the NFS
server with any other set of mappings, it breaks.

This is after the initial v5.10 merge window, so hopefully this patchset
can be reconsidered, and maybe we can make forward progress? I think that
it takes a relatively conservative approach in enabling user namespaces,
and it prevents the case where someone is using auth_gss (for now), as the
mappings are non-trivial.

Changes since v3:
  * Rebase atop Anna's tree
Changes since v2:
  * Removed samples
  * Split out NFSv2/v3 patchset from NFSv4 patchset
  * Added restrictions around use
Changes since v1:
  * Added samples

Sargun Dhillon (2):
  NFS: NFSv2/NFSv3: Use cred from fs_context during mount
  NFSv4: Refactor NFS to use user namespaces

 fs/nfs/client.c     | 10 ++++++++--
 fs/nfs/nfs4client.c | 27 ++++++++++++++++++++++++++-
 fs/nfs/nfs4idmap.c  |  2 +-
 fs/nfs/nfs4idmap.h  |  3 ++-
 4 files changed, 37 insertions(+), 5 deletions(-)


base-commit: 8c39076c276be0b31982e44654e2c2357473258a
-- 
2.25.1