bpf_set_dentry_xattr(9)

📦 version 7.3.1, in nixpkgs unstable

💅 bpf_set_dentry_xattr — a Kernel API Manual moment ✨

okay bestie, welcome to bpf_set_dentry_xattr(9) 🎀 the kernel API manual page that's about to teach you how to slap an xattr onto a dentry. no cap, it's lowkey niche but highkey useful. iykyk 🦋

✨ NAME ✨

bpf_set_dentry_xattr — set a xattr of a dentry 🌸

🫶 SYNOPSIS 🫶

__bpf_kfunc int bpf_set_dentry_xattr (struct dentry *dentry , const char
*name__str , const struct bpf_dynptr *value_p , int flags );

that's the whole signature, bestie, copy it exactly, do not improvise 💅

💖 ARGUMENTS 💖

  • dentry — bestie this is the dentry to get xattr from 👀 (yes, the manpage literally says "get" here, we're just reporting the facts, don't come for me 😭)
  • name__str — the name of the xattr ✨
  • value_p — the xattr value 🍓
  • flags — flags to pass into filesystem operations 🎀

🌈 DESCRIPTION 🌈

so what does this actually do? it sets xattr name__str of dentry to the value in value_ptr. periodt. that's the whole vibe 🌟

🚨 security check incoming 🚨 for security reasons, only name__str with the prefix "security.bpf." is allowed. like, only that prefix, nothing else, the kernel is not playing around 💀

also important, bestie, and i need you to hear me on this one:

the caller has not locked dentry->d_inode. 👑

that's not a suggestion, that's a state of the world. respect it 🙈

🔥 RETURN 🔥

  • 0 on success 🥳
  • a negative value on error 😭

🦋 SEE ALSO 🦋

kernel file ./fs/bpf_fs_kfuncs.c plus the whole friend group 💜:

🧚 sign-off 🧚

this icon was brought to you by ./fs, dated October 2026, and it lives under the name bpf_set_dentry_xattr(9) 🌸 go set some xattrs, bestie, but only with the right prefix 💅✨👑

📦 where this page comes from