d_really_is_negative(9)

💅 d_really_is_negative — the kernel API manual, bestie edition

okay so this is a page from the Kernel API Manual and it's about d_really_is_negative(9) — yes that's the actual name, no we're not renaming it, it's iconic as is 🎀

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✨ NAME ✨

d_really_is_negative — figure out if a dentry is really negative, and by "really" we mean ignoring fallthroughs entirely 💅

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🌸 SYNOPSIS 🌸

bool d_really_is_negative (const struct dentry *dentry );

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🦋 ARGUMENTS 🦋

• dentry — the dentry you're side-eyeing 👀 like, the one in question, the one we're investigating

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💖 DESCRIPTION 💖

Returns true if the dentry represents either an absent name or a name that doesn't map to an inode (ie. ->d_inode is NULL). no cap, that's the whole vibe check ✨

The dentry could represent a true miss, a whiteout that isn't represented by a 0,0 chardev, or a fallthrough marker in an opaque directory. literally all three possibilities, and we're not picking favourites 🫶

Note! okay listen, three things, and they matter 👑 1. This should be used *only* by a filesystem to examine its own dentries. It should not be used to look at some other filesystem's dentries. respectfully, stay in your lane 💀 2. It should also be used in combination with d_inode to get the inode. like, together, as a duo, main character energy 🤝 3. The dentry may have something attached to ->d_lower and the type field of the flags may be set to something other than miss or whiteout. so like, don't assume, bestie 🙈

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🔥 SEE ALSO 🔥

• Kernel file ./include/linux/dcache.h
• dget_dlock(9)
• dget(9)
• d_unhashed(9)
• d_really_is_positive(9) — the flip side, the other half of the story ⭐
• d_inode(9)
• d_inode_rcu(9)
• d_backing_inode(9)
• d_real(9)
• d_real_inode(9)

the whole friend group, go say hi 🌈

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sign-off time 🎀 this little gem lives in ./include/linux, dated October 2026, and it's filed under d_really_is_negative(9) — the (9) means kernel API manual, iykyk. slay, go read your dentries responsibly 💜