nfsd4_decode_bitmap4(9)

💅 nfsd4_decode_bitmap4(9) — like, the Kernel API Manual but make it make sense

okay bestie, gather round, because we're diving into nfsd4_decode_bitmap4(9) and honestly? it's giving "small function, big feelings." this is the one that decodes an NFSv4 bitmap4 for you, and yes, you're gonna understand it. 🎀

---

✨ NAME ✨

nfsd4_decode_bitmap4 — decode an NFSv4 bitmap4, no cap 💖

---

🌸 SYNOPSIS 🌸

__be32 nfsd4_decode_bitmap4 (struct nfsd4_compoundargs *argp , u32
*bmval , u32 bmlen );

literal slay. copy it exactly, don't @ me. 🫶

---

🦋 ARGUMENTS 🦋

• argp — the NFSv4 compound argument structure. it's the main character of this whole operation, fr fr. 👑
• bmval — a pointer to an array of u32's, and that array is where we decode into. it's the destination, the vibe, the moment. ✨
• bmlen — the size of the bmval array. gotta know how big the canvas is before you start painting. 🎨

---

💜 DESCRIPTION 💜

okay so here's the whole situation. the server needs to return nfs_ok rather than nfserr_bad_xdr when it runs into bitmaps containing bits it does not recognize. that's the rule, that's the assignment, periodt. 🔥

and "bits it does not recognize" includes bits in bitmap words past WORDn, where WORDn is the last bitmap WORD the implementation currently supports. so like, we're out here past the edge of what we know, and we're chill about it. 💅

which is why we are careful here to simply ignore bits in bitmap words that this implementation has yet to support explicitly. not us pretending they don't exist — us being polite and moving on. it's called boundaries, look it up. 🙈

Return values:

• nfs_ok — bmval populated successfully. ate, no crumbs. 🍓
• nfserr_bad_xdr — the encoded bitmap was invalid. not slay, but that's the error, and we report it. 😭

ngl bestie, the whole point of this one is tolerance — unknown bits get the silent treatment, not an error. do not accidentally "fix" that. 💀

---

🌈 SEE ALSO 🌈

• Kernel file ./fs/nfsd/nfs4xdr.c
• svcxdr_tmpalloc(9)
• nfsd4_encode_notify_event(9)
• nfsd4_encode_dir_attr_change(9)
• nfsd4_encode_replay(9)

all of these, in this exact order, because we do not skip entries in the group chat. 🧚

---

and that's the page!! sourced straight from ./fs/nfsd and dated October 2026 — go forth and decode, icon. 👑💖⭐