d_alloc_pseudo(9)

📦 version 7.3.1, in nixpkgs unstable

💅 d_alloc_pseudo(9) — like, the manual page, bestie

Okay so real talk, this is d_alloc_pseudo from the Kernel API Manual, section 9 (iykyk — that's the kernel API section, not your average man page energy). Buckle up 🎀

✨ NAME ✨

d_alloc_pseudo — allocate a dentry (for lookup-less filesystems) 🦋

So basically: you want a dentry, but your filesystem is so not into lookups. This is the function for that vibe.

🌸 SYNOPSIS 🌸

struct dentry * d_alloc_pseudo (struct super_block *sb , const struct
       qstr *name );

Note the spacing in the original signature, bestie — it's literally struct super_block *sb , const struct qstr *name with that space before the comma. Don't come for me, that's just how it is 💀

🫶 ARGUMENTS 🫶

  • sb — the superblock. The big one. The main character of your filesystem's mount 🌈
  • name — a qstr of the name. That's the quick-string situation, not a full char *, okay? ✨

💖 DESCRIPTION 💖

Okay so picture this: you have a filesystem that just pins its dentries in memory and never ever performs lookups. Not once. Never. Zero lookup energy. For a filesystem like that, this function returns an unhashed IS_ROOT dentry — iconic, rooty, and definitely not living in the hash table 👑

What's it for? Pipes, sockets et.al. — the stuff that should never be anyone's children or parents. Like, do not put these in your family tree, they are not participating in that whole hierarchy situation. Fr fr. 🙈

And here's the spicy detail: unlike all other dentries, these ones will not have an RCU delay between dropping the last reference and freeing them. No grace period era, they just go 💀

The only user is alloc_file_pseudo, and that's what should be considered a public interface. Don't use directly. 🚨 Like, seriously bestie — that's the whole warning. Use alloc_file_pseudo, not this.

👑 SEE ALSO 👑

Look at this list, it's giving "the entire dentry lore dumped in one place" — Kernel file ./fs/dcache.c:

Anyway, that's the whole page, no cap. This little gem lives in <code>./fs</code> and the version/date stamped on it is October 2026 — so like, future-era manpage energy, we love to see it. Byeee 🧚💜

📦 where this page comes from