Re: [PATCH 00/23 - V5] NFS: Remove generic RPC credentials.

[J. Bruce Fields]

On Mon, Dec 03, 2018 at 11:30:30AM +1100, NeilBrown wrote:
> This is the same series as posted on 07 November, modified slightly
> to match some recent code changes upstream - nothing substantial.
> 
> General description:
> 
> There doesn't seem to be a maintainer for the 'cred' code, so I don't
> know who to ask to approve the first 4 patches.  Maybe if the NFS
> team like them, they can just go to Linus with a note for him to look
> at them if he wants to.

For what it's worth: all my usual tests still pass with this series
applied.  And the nfsd (and common) parts are unlikely to conflict with
anything of mine.

Otherwise: sounds like a reasonable idea, but I haven't gotten a chance
to review the patches in any detail.

--b.

> 
> The original motivation for this was performance.  In some
> circumstances the cred caches can get big and particularly can get
> long chains.  The hash function has been changed at least once to
> improve the hashing and it still isn't perfect.
> Rather than improving pruning of the cache, or resizing the hashtable
> etc, it is easiest to just get rid of it.
> 
> As well as discarding generic credentials completely (using 'struct
> cred' instead), we also stop storing AUTH_UNIX credentials in a hash
> table - that brings no value.  Just allocate as needed and discard
> when finished with.
> So the only hash table will still have is for AUTH_GSS.
> One of the main triggers for hashtable problems was users changing
> groups a lot, so there would be many entries for the one user, each
> with a different set of groups.  That doesn't apply for
> AUTH_GSS as the groupids on the client are ignored.
> 
> That was the original motivation, but as I worked on it, I realized
> that it was making a log of code simpler.
> 
>  44 files changed, 550 insertions(+), 925 deletions(-)
> 
> That is sufficient motivation in itself I think.
> 
> Thanks,
> NeilBrown
> 
> 
> ---
> 
> NeilBrown (23):
>       cred: add cred_fscmp() for comparing creds.
>       cred: add get_cred_rcu()
>       cred: export get_task_cred().
>       cred: allow get_cred() and put_cred() to be given NULL.
>       SUNRPC: add 'struct cred *' to auth_cred and rpc_cred
>       SUNRPC: remove groupinfo from struct auth_cred.
>       SUNRPC: remove uid and gid from struct auth_cred
>       SUNRPC: remove machine_cred field from struct auth_cred
>       NFSv4: add cl_root_cred for use when machine cred is not available.
>       NFSv4: don't require lock for get_renew_cred or get_machine_cred
>       SUNRPC: discard RPC_DO_ROOTOVERRIDE()
>       NFS/SUNRPC: don't lookup machine credential until rpcauth_bindcred().
>       SUNRPC: introduce RPC_TASK_NULLCREDS to request auth_none
>       SUNRPC: add side channel to use non-generic cred for rpc call.
>       NFS: move credential expiry tracking out of SUNRPC into NFS.
>       SUNRPC: remove RPCAUTH_AUTH_NO_CRKEY_TIMEOUT
>       NFS: change access cache to use 'struct cred'.
>       NFS: struct nfs_open_dir_context: convert rpc_cred pointer to cred.
>       NFS/NFSD/SUNRPC: replace generic creds with 'struct cred'.
>       SUNRPC: remove generic cred code.
>       SUNRPC: remove crbind rpc_cred operation
>       SUNRPC: simplify auth_unix.
>       SUNRPC discard cr_uid from struct rpc_cred.
> 
> 
>  fs/lockd/clntproc.c                       |    6 -
>  fs/nfs/blocklayout/blocklayout.c          |    2 
>  fs/nfs/client.c                           |    9 -
>  fs/nfs/delegation.c                       |   28 +--
>  fs/nfs/delegation.h                       |   10 -
>  fs/nfs/dir.c                              |   59 ++----
>  fs/nfs/flexfilelayout/flexfilelayout.c    |   64 +++---
>  fs/nfs/flexfilelayout/flexfilelayout.h    |    8 -
>  fs/nfs/flexfilelayout/flexfilelayoutdev.c |   16 +-
>  fs/nfs/inode.c                            |   13 +
>  fs/nfs/internal.h                         |    8 -
>  fs/nfs/nfs3proc.c                         |    4 
>  fs/nfs/nfs4_fs.h                          |   65 +++---
>  fs/nfs/nfs4client.c                       |    4 
>  fs/nfs/nfs4proc.c                         |  150 +++++++--------
>  fs/nfs/nfs4renewd.c                       |    9 -
>  fs/nfs/nfs4session.c                      |    5 
>  fs/nfs/nfs4state.c                        |  129 ++++++-------
>  fs/nfs/pagelist.c                         |    2 
>  fs/nfs/pnfs.c                             |   14 +
>  fs/nfs/pnfs.h                             |   10 -
>  fs/nfs/pnfs_dev.c                         |    4 
>  fs/nfs/pnfs_nfs.c                         |    2 
>  fs/nfs/proc.c                             |    2 
>  fs/nfs/unlink.c                           |   15 -
>  fs/nfs/write.c                            |   24 ++
>  fs/nfsd/nfs4callback.c                    |   31 +--
>  fs/nfsd/state.h                           |    2 
>  include/linux/cred.h                      |   26 ++-
>  include/linux/nfs_fs.h                    |   13 +
>  include/linux/nfs_fs_sb.h                 |    2 
>  include/linux/nfs_xdr.h                   |   16 +-
>  include/linux/sunrpc/auth.h               |   51 -----
>  include/linux/sunrpc/clnt.h               |    1 
>  include/linux/sunrpc/sched.h              |    6 -
>  kernel/cred.c                             |   58 ++++++
>  net/sunrpc/Makefile                       |    2 
>  net/sunrpc/auth.c                         |  116 ++++++-----
>  net/sunrpc/auth_generic.c                 |  293 -----------------------------
>  net/sunrpc/auth_gss/auth_gss.c            |   47 +----
>  net/sunrpc/auth_null.c                    |    4 
>  net/sunrpc/auth_unix.c                    |  110 +++--------
>  net/sunrpc/clnt.c                         |   26 +--
>  net/sunrpc/sched.c                        |    5 
>  44 files changed, 551 insertions(+), 920 deletions(-)
>  delete mode 100644 net/sunrpc/auth_generic.c
> 
> --
> Signature