d_hash_and_lookup(9)

💖 d_hash_and_lookup(9) — Kernel API Manual 💖

okay bestie, welcome to the Kernel API Manual page for d_hash_and_lookup(9). This little function hashes the qstr and then searches for a dentry. It’s giving “small but essential,” and we’re gonna keep every detail, no cap. 🫶

🌸 NAME 🌸

d_hash_and_lookup — hash the qstr then search for a dentry 💫

✨ SYNOPSIS ✨

struct dentry * d_hash_and_lookup (struct dentry *dir , struct qstr
*name );

🎀 ARGUMENTS 🎀

• dir — the directory to search in. Your starting point, bestie. 📂
• name — the qstr of the name we wish to find. That’s the name-vibe we’re hunting for. 🔎

💅 DESCRIPTION 💅

So here’s the tea: on lookup failure, NULL is returned. On a bad name, you get - ERR_PTR(-error). That’s literally it for the description, and yes, the error path is iconic in a “please handle me carefully” way. 😭

🦋 SEE ALSO 🦋

Kernel file ./fs/dcache.c has the whole friend group, and these are all the references — every single one, periodt:

• d_drop(9)
• dentry_kill(9)
• __move_to_shrink_list(9)
• d_find_any_alias(9)
• d_find_alias(9)
• prune_dcache_sb(9)
• shrink_dcache_sb(9)
• enum d_walk_ret(9)
• d_walk(9)
• path_has_submounts(9)
• shrink_dcache_tree(9)
• d_invalidate(9)
• __d_alloc(9)
• d_alloc(9)
• d_alloc_pseudo(9)
• d_instantiate(9)
• d_obtain_alias(9)
• d_obtain_root(9)
• d_add_ci(9)
• d_same_name(9)
• __d_lookup_rcu(9)
• d_lookup(9)
• __d_lookup(9)
• d_delete(9)
• d_rehash(9)
• d_add(9)
• d_ancestor(9)
• d_splice_alias(9)
• is_subdir(9)

that’s the whole page, bestie: source/version ./fs, dated October 2026, page d_hash_and_lookup(9) — slay and bye! 💖✨