nlm4svc_proc_nm_lock(9)

📦 version 7.3.1, in nixpkgs unstable

🌸 nlm4svc_proc_nm_lock — the Kernel API Manual, section 9 ✨

okay so bestie, gather round, because we're diving into nlm4svc_proc_nm_lock(9) — yes that's the section 9 kernel API manual, and yes it's giving "niche but iconic." This is the NM_LOCK proc, aka Establish a non-monitored lock. 💅

🎀 SYNOPSIS 🎀

__be32 nlm4svc_proc_nm_lock (struct svc_rqst *rqstp );

like… that's the whole signature. short and slay.

🦋 ARGUMENTS 🦋

  • rqstp — the RPC transaction context. that's it, that's the one argument. she's lowkey carrying the whole request on her shoulders 💖

⭐ RETURN ⭐

  • rpc_success — RPC executed successfully. we love a clean win 🎉
  • rpc_drop_reply — do not send an RPC reply. no reply, no problem, we're ghosting the client 🙈

🔥 DESCRIPTION 🔥

okay so the RPC synopsis goes like this, no cap:

nlm4_res NLMPROC4_NM_LOCK(nlm4_lockargs) = 22;

Permissible procedure status codes, bestie, listen up — these are the ones you're allowed to return:

  • NLM4_GRANTED — the requested lock was granted. periodt. lock secured 👑
  • NLM4_DENIED — the requested lock conflicted with existing lock reservations for the file. somebody else got there first 😭
  • NLM4_DENIED_NOLOCKS — the server could not allocate the resources needed to process the request. she's out of budget, literally 💀
  • NLM4_BLOCKED — the blocking request cannot be granted immediately. the server will send an NLMPROC4_GRANTED callback to the client when the lock can be granted. so like… not right now, but circle back 🫶
  • NLM4_DENIED_GRACE_PERIOD — the server has recently restarted and is re-establishing existing locks, and is not yet ready to accept normal service requests. she's in her healing era, give her a sec 🌸

and the Linux NLM server implementation also returns these extra ones — the deluxe edition:

  • NLM4_DEADLCK — the request could not be granted and blocking would cause a deadlock. mutually assured destruction, we're not doing that 🚫
  • NLM4_STALE_FH — the request specified an invalid file handle. expired, stale, not the vibe 🥀
  • NLM4_FBIG — the request specified a length or offset that exceeds the range supported by the server. too big, too much, over it 💅
  • NLM4_FAILED — the request failed for an unspecified reason. it's giving mystery, it's giving "we don't know either" 😵‍💫

💜 SEE ALSO 💜

Kernel file ./fs/lockd/svc4proc.c — go read the source, iykyk — plus her entire friend group:

and that's the page bestie!! 🌈 this little gem lives in ./fs/lockd and it was dated October 2026 — mark your calendars, she's a time traveler 🕰️✨ mwah, study hard, and don't forget to actually send the reply (unless it's rpc_drop_reply, in which case absolutely do not) 🎀💖

📦 where this page comes from