Re: [PATCH 0/8] nfsd: reduce the scope of the nfsd_mutex

[NeilBrown]

On Tue, 22 Sep 2026, Jeff Layton wrote:
> Currently much of nfsd's administration is serialized under the global
> nfsd_mutex, even though most of the objects managed under it are
> segregated by net namespace.
> 
> This patchset does a couple of small cleanups and then adds a new
> per-net mutex and moves all of the appropriate per-net data structures
> to be protected by it instead of the global mutex. The filecache is
> given its own mutex, and the global mutex is renamed and left for
> managing just the few remaning global objects.
> 
> I also had an LLM cook up some selftests so we can hopefully keep all of
> this working properly in the future.
> 
> Please consider for v7.4.

Thanks for doing this Jeff - it is long past time :-)

It all looks good to me - except the selftests which I didn't look at.

Thanks,
NeilBrown



> 
> Thanks,
> Jeff
> 
> Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx>
> ---
> Jeff Layton (8):
>       nfsd: clear NFSD_NET_UP before dropping the generic resource reference
>       nfsd: make max_blksize a per-namespace setting
>       nfsd: move the control plane to a per-namespace mutex
>       nfsd: rename nfsd_mutex to nfsd_global_mutex
>       nfsd: give the open file cache its own mutex
>       selftests/nfsd: factor the netlink plumbing into a shared header
>       selftests/nfsd: add cross-namespace isolation tests
>       selftests/nfsd: add a cross-namespace control-plane soak
> 
>  fs/nfsd/export.c                                   |  22 +-
>  fs/nfsd/filecache.c                                |  36 +-
>  fs/nfsd/netns.h                                    |  16 +
>  fs/nfsd/nfs4proc.c                                 |   4 +-
>  fs/nfsd/nfs4state.c                                |   8 +-
>  fs/nfsd/nfsctl.c                                   | 129 ++---
>  fs/nfsd/nfsd.h                                     |   4 +-
>  fs/nfsd/nfssvc.c                                   | 146 ++++--
>  tools/testing/selftests/nfsd/Makefile              |   2 +
>  tools/testing/selftests/nfsd/config                |   6 +
>  tools/testing/selftests/nfsd/nfsd_netlink.h        | 319 ++++++++++++
>  .../testing/selftests/nfsd/nfsd_netlink_listener.c | 301 +----------
>  tools/testing/selftests/nfsd/nfsd_netns_isolation  | Bin 0 -> 49192 bytes
>  .../testing/selftests/nfsd/nfsd_netns_isolation.c  | 450 ++++++++++++++++
>  tools/testing/selftests/nfsd/nfsd_netns_stress     | Bin 0 -> 39232 bytes
>  tools/testing/selftests/nfsd/nfsd_netns_stress.c   | 572 +++++++++++++++++++++
>  tools/testing/selftests/nfsd/settings              |   2 +-
>  17 files changed, 1580 insertions(+), 437 deletions(-)
> ---
> base-commit: aeaddc6a3711283c09a9183068897d4fe1fb464f
> change-id: 20260918-nfsd-per-net-mutex-8655764940ac
> 
> Best regards,
> -- 
> Jeff Layton <jlayton@xxxxxxxxxx>
> 
>