[PATCH v7 0/3] add rpc_status netlink support for NFSD

[Lorenzo Bianconi <lorenzo@kernel.org>]

Introduce rpc_status netlink support for NFSD in order to dump pending
RPC requests debugging information from userspace.
The new code can be tested with the user-space tool reported below:
https://github.com/LorenzoBianconi/nfsd-rpc-netlink-monitor/tree/main

Changes since v6:
- report info to user-space through netlink and get rid of the related
  entry in the procfs

Changes since v5:
- add missing delimiters for nfs4 compound ops
- add a header line for rpc_status handler
- do not dump rq_prog
- do not dump rq_flags in hex

Changes since v4:
- rely on acquire/release APIs and get rid of atomic operation
- fix kdoc for nfsd_rpc_status_open
- get rid of ',' as field delimiter in nfsd_rpc_status hanlder
- move nfsd_rpc_status before nfsd_v4 enum entries
- fix compilantion error if nfsdv4 is not enabled

Changes since v3:
- introduce rq_status_counter in order to detect if the RPC request is
  pending and RPC info are stable
- rely on __svc_print_addr to dump IP info

Changes since v2:
- minor changes in nfsd_rpc_status_show output

Changes since v1:
- rework nfsd_rpc_status_show output

Changes since RFCv1:
- riduce time holding nfsd_mutex bumping svc_serv refcoung in
  nfsd_rpc_status_open()
- dump rqstp->rq_stime
- add missing kdoc for nfsd_rpc_status_open()

Link: https://bugzilla.linux-nfs.org/show_bug.cgi?id=3D3D366

Lorenzo Bianconi (3):
  SUNRPC: export nfsd4_op_name utility routine
  SUNRPC: export svc_proc_name utility routine
  NFSD: add rpc_status netlink support

 fs/nfsd/nfs4proc.c         |   4 +-
 fs/nfsd/nfsctl.c           | 275 +++++++++++++++++++++++++++++++++++++
 fs/nfsd/nfsd.h             |  25 ++++
 fs/nfsd/nfssvc.c           |  15 ++
 fs/nfsd/state.h            |   2 -
 include/linux/sunrpc/svc.h |   1 +
 include/uapi/linux/nfs.h   |  54 ++++++++
 net/sunrpc/svc.c           |   2 +-
 8 files changed, 372 insertions(+), 6 deletions(-)

-- 
2.41.0