bpf_set_dentry_xattr_locked(9)

📦 version 7.3.1, in nixpkgs unstable

💅 bpf_set_dentry_xattr_locked(9) — from the Kernel API Manual, bestie ✨

okay so picture this: you're deep in kernel-land, you've got a dentry, you've got an xattr name, you've got a value, and you just need to stick that value onto that dentry. that's this function. it's giving lowkey niche but highkey iconic. let's get into it 🫶

✨ NAME ✨

bpf_set_dentry_xattr_locked — set a xattr of a dentry 💖

🌸 SYNOPSIS 🌸

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

like, that's the whole signature, no notes, she's beautiful 😭

🎀 ARGUMENTS 🎀

  • dentry — the dentry you're pulling the xattr from. that's the main character right there 👑
  • name__str — the name of the xattr. and yes bestie, the double underscore is real, that's not a typo, write it exactly like that 💀
  • value_p — the xattr value. this is the actual payload, the vibe, the content 🌈
  • flags — flags that get passed straight into filesystem operations. so whatever the fs wants, the fs gets 🧚

🦋 DESCRIPTION 🦋

so what she actually does: she sets the xattr name__str of dentry to the value in value_ptr. that's the whole assignment. slay ✨

⚠️ and now the important part, no cap: for security reasons, only name__str with the prefix "security.bpf." is allowed. that's not a suggestion, that's the rule. anything else? not today, bestie 🙈

also, heads up: the caller already locked dentry->d_inode. that's on you, not on her. she's not doing the locking, she's just showing up to a party that's already locked (in a good way) 🔥

⭐ RETURN ⭐

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

that's it. binary queen. periodt 💅

💜 SEE ALSO 💜

  • Kernel file ./fs/bpf_fs_kfuncs.c — that's where the magic lives 📁

and the whole friend group, obviously:

like, the whole xattr cinematic universe fr fr 🌸

okay and finally, the lil sign-off: this page comes from ./fs, dated October 2026, and it's all about bpf_set_dentry_xattr_locked(9). mwah 💋 go forth and set those xattrs, but only the "security.bpf." ones, iykyk 🎀

📦 where this page comes from