Re: [PATCH v1 0/3] nfsdctl: list NFSv4 clients

[Jeff Layton <jlayton@kernel.org>]

On Tue, 2026-08-25 at 06:52 +0000, Prabhakar Pujeri wrote:
> Add the userspace consumer for the companion NFSD Netlink client-state
> series, whose cover Message-ID is:
> 
>   <cover.1787638668.git.prabhakar.pujeri@dell.com>
> 
> The series mirrors the kernel ABI split:
> 
>   1. Display the explicit recovery-grace value returned by threads-get.
>   2. Add a privileged `nfsdctl clients` table for basic client state.
>   3. Extend the table with session and stateid record counts.
> 
> Attribute presence remains the compatibility boundary. An older kernel
> omits the grace value, and missing count attributes are displayed as
> dashes. The bundled UAPI header permits building before the new kernel
> header is installed. The configure probe requires the final count
> attribute, so a system header containing only the base client command also
> falls back to the complete bundled copy.
> 
> Validation performed:
> 
>   - full nfs-utils build at each applicable patch state
>   - final `make check`: no failures; one environment-dependent test skipped
>   - bundled nfsd Netlink UAPI compared byte-for-byte with the kernel copy
>   - two-vCPU QEMU test with a live NFSv4.2 loopback mount
>   - grace yes/no transitions displayed by `nfsdctl threads`
>   - live client row showing one session, open stateid, lock stateid, and
>     delegation stateid; zero layout stateids
>   - callback, reclaim, lease, peer-address, and client-ID fields checked
> 
> The series is based on the current nfs-utils master branch. The exact base
> is recorded in the base-commit trailer below.
> 
> Prabhakar Pujeri (3):
>   nfsdctl: report NFSv4 grace state
>   nfsdctl: add a command to list NFSv4 clients
>   nfsdctl: display per-client NFSv4 state usage
> 
>  configure.ac                   |   2 +-
>  support/include/nfsd_netlink.h |  41 +++++
>  utils/nfsdctl/nfsdctl.8        |  22 ++-
>  utils/nfsdctl/nfsdctl.adoc     |  15 +-
>  utils/nfsdctl/nfsdctl.c        | 268 +++++++++++++++++++++++++++++++++
>  5 files changed, 345 insertions(+), 3 deletions(-)
> 
> 
> base-commit: 67ed1bdb1af1c70a5fd3b377a997401b7676b827

Sashiko has some comments about this that probably need to be addressed
before we apply these. There is potential for a softlockup in patch #3,
in particular:

https://sashiko.dev/#/patchset/cover.1787638668.git.prabhakar.pujeri%40dell.com
-- 
Jeff Layton <jlayton@kernel.org>