d_backing_inode(9)

✨ d_backing_inode — kernel API manual, bestie edition ✨

Okay so real quick, this page lives in the Kernel API Manual (that's the manual name, iykyk 💅) and it's about one tiny helper that lowkey does a lot. Let's get into it 🫶

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💖 NAME 💖

d_backing_inode — get the upper or lower inode that we should actually be using 👑

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🌸 SYNOPSIS 🌸

struct inode * d_backing_inode (const struct dentry *upper );

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🎀 ARGUMENTS 🎀

• upper — the upper layer 💫 (that's it, that's the whole argument, she's simple like that)

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🦋 DESCRIPTION 🦋

So this is the helper you're supposed to reach for when you want to get at the inode that would be used if this dentry were to be opened as a file. No cap, that's literally her whole job ✨

And here's the cute part: the inode may be on the upper dentry, or it may be on a lower dentry that's pinned by the upper one. Either way, d_backing_inode is the one who finds it for you 🧚

But listen — normal filesystems should not use this to access their own inodes. Like, that's not what she's for, bestie. Read that one twice 🙈

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🌈 SEE ALSO 🌈

Kernel file ./include/linux/dcache.h — plus the whole friend group:

• dget_dlock(9)
• dget(9)
• d_unhashed(9)
• d_really_is_negative(9)
• d_really_is_positive(9)
• d_inode(9)
• d_inode_rcu(9)
• d_real(9)
• d_real_inode(9)

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And that's the page, periodt 💅 Big sign-off energy: this one comes from the source tree at ./include/linux, dated October 2026, and it's filed under d_backing_inode(9) in the Kernel API Manual. Obsessed, honestly 🎀💖🔥