fscrypt_fname_siphash(9)

💅 fscrypt_fname_siphash 💅

okay bestie, welcome to the Kernel API Manual entry for fscrypt_fname_siphash(9) — yes that's the whole name, yes it's a mouthful, no we're not shortening it, she earned it 👑

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✨ NAME ✨

fscrypt_fname_siphash — calculate the SipHash of a filename 🌸

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🦋 SYNOPSIS 🦋

u64 fscrypt_fname_siphash (const struct inode *dir , const struct qstr
*name );

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🎀 ARGUMENTS 🎀

• dir — the parent directory, the one holding the keys to the kingdom 🔑
• name — the filename we're calculating the SipHash of, the main character of this whole operation 💖

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💜 DESCRIPTION 💜

so here's the tea ☕ — you hand over a plaintext filename name, and a directory dir. but not just any directory, bestie: dir has to be one that uses SipHash as its dirhash method and has had its fscrypt key set up already. both. no skipping steps 🙈

given all that, this function calculates the SipHash of that name using the directory's secret dirhash key. literally using the dir's own private key, iykyk. that's it, that's the function 💅

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🌈 RETURN 🌈

the SipHash of name using the hash key of dir ✨ — that's the u64 you get back, no cap 🫶

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👑 SEE ALSO 👑

• Kernel file ./fs/crypto/fname.c — the source, go read it, she's iconic 📖
• fscrypt_fname_encrypt(9)
• fname_decrypt(9)
• fscrypt_fname_encrypted_size(9)
• fscrypt_fname_alloc_buffer(9)
• fscrypt_fname_free_buffer(9)
• fscrypt_fname_disk_to_usr(9)
• fscrypt_setup_filename(9)
• fscrypt_match_name(9)

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and that's the vibe check, bestie 🧚 — this whole page came out of ./fs/crypto, dated October 2026, and it's titled fscrypt_fname_siphash(9). slay, go hash some filenames 💖✨🎀