may_write_xattr(9)

📦 version 7.3.1, in nixpkgs unstable

💅 may_write_xattr(9) — the kernel API manual, bestie edition 🎀

okay so bestie, welcome to the may_write_xattr(9) page ✨ it's a kernel API manual situation, and honestly it's giving "tiny function, big vibes." let's get into it 🦋

🌸 NAME 🌸

may_write_xattr — literally just vibe-checks whether an inode allows writing xattr. that's the whole job. iconic, honestly 👑

✨ SYNOPSIS ✨

int may_write_xattr (struct mnt_idmap *idmap , struct inode *inode );

🫶 ARGUMENTS 🫶

  • idmap — the idmap of the mount that the inode was found from. like, which mount did this inode come from, bestie, we need receipts 📋
  • inode — the inode you're trying to set an xattr on. the main character of this whole function, fr fr 💜

💖 DESCRIPTION 💖

okay so what this actually does: it checks whether the inode allows writing xattrs. vibe check, but for permissions 💅

specifically — and this is the important part, no cap — we can never set or remove an extended attribute on a read-only filesystem, or on an immutable / append-only inode. that's a hard no. not happening. the kernel said what it said 🙈

we also need to make sure the inode has a mapping in the mount, so we don't risk writing back invalid i_{g,u}id values. like, we're not out here writing garbage back, that's not the move 😭

⭐ RETURN ⭐

  • on success, zero is returned 🎀
  • on error, a negative errno is returned 💀

that's it. that's the return value. simple, clean, slay ✨

🦋 SEE ALSO 🦋

kernel file ./fs/xattr.c — go read it, iykyk 🧚

like, the whole xattr friend group showed up to the function. we love a supportive community 🌈💖

and that's the page, bestie! 🫶 this gem comes from ./fs, dated October 2026, and the manual name is may_write_xattr(9). go forth and write those xattrs — responsibly, obviously 💅✨
📦 where this page comes from