d_ancestor(9)

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

okay so real talk, this page lives in the Kernel API Manual and it's about one tiny function that answers a very specific question: is this dentry an ancestor of that dentry, and if so which one do i hand back? that's the whole vibe. let's get into it 🫶

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✨ NAME ✨

d_ancestor — search for an ancestor, no cap 🔍

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🌸 SYNOPSIS 🌸

struct dentry * d_ancestor (struct dentry *p1 , struct dentry *p2 );

that's it. two pointers in, one pointer out. iconic signature tbh 💅

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🎀 ARGUMENTS 🎀

• p1 — the ancestor dentry 👑 (the one that might be the parent-ish one)
• p2 — the child dentry 🍓 (the one we're checking on)

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🦋 DESCRIPTION 🦋

so here's the tea ☕ — this function returns the ancestor dentry of p2 which is a child of p1, if p1 is an ancestor of p2. otherwise? it gives you NULL. literally that simple. not me explaining this in one sentence 😭

lowkey the whole function is a conditional. no side quests, no hidden options, just vibes and a pointer (or NULL). ✨

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🌈 SEE ALSO 🌈

bestie we are NOT done, there is a whole friend group 💖 the kernel file is ./fs/dcache.c and here's everybody else you should go say hi to:

• 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_hash_and_lookup(9)
• d_delete(9)
• d_rehash(9)
• d_add(9)
• d_splice_alias(9)
• is_subdir(9)

like. that's the entire dcache extended universe, go read them all, i'll wait 🧚💜

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okay that's the page!! it's from ./fs, dated October 2026, and yeah the page itself is d_ancestor(9) — mwah, slay, periodt 💋🎀✨