ecryptfs_encrypt_page(9)

🌸 ecryptfs_encrypt_page(9) 🌸

okay bestie, welcome to the kernel API manual, eCryptfs edition 💅 this one's short and sweet but she's important, so pay attention.

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✨ NAME ✨

ecryptfs_encrypt_page —

so like… the description part after the dash is literally empty in the source 🙈 no cap, there's nothing there. She's a mystery. But don't worry, the rest of the page has you covered 🫶

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🦋 SYNOPSIS 🦋

int ecryptfs_encrypt_page (struct folio *folio );

that's it, that's the whole vibe check. one folio, one int back. iconic behavior honestly 👑

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🎀 ARGUMENTS 🎀

• folio — the folio, mapped from the eCryptfs inode for the file 🗂️ she's holding the decrypted content that needs to get encrypted — and heads up, it's encrypted to a temporary page, not in place (so we're not overwriting the original in the moment, okay?? we're classy) — and then written out to the lower file. slay.

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💖 DESCRIPTION 💖

so the whole job here is: encrypt an eCryptfs page 🔐 and it's done on a per-extent basis. ngl that detail matters.

and here's the part where you gotta listen — eCryptfs pages can straddle the lower pages 😭 like, imagine the scenario:

• the file got created on a machine with an 8K page size, which gives you an 8K header,
• then that file gets copied onto a host with a 32K page size,
• so now when you read page 0 of the eCryptfs file, you're gonna read and decrypt 24K of page 0 of the lower file, and then read and decrypt 8K of page 1 of the lower file 🌀

like… she spans multiple pages, she contains multitudes, she's giving main character energy across page boundaries 💫 the way that it just keeps going into the next page, honestly obsessed.

💀 Return value tea: returns zero on success; negative on error. that's the whole contract bestie, don't forget it.

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🌈 SEE ALSO 🌈

• Kernel file ./fs/ecryptfs/crypto.c
• ecryptfs_from_hex(9)
• ecryptfs_derive_iv(9)
• ecryptfs_init_crypt_stat(9)
• ecryptfs_destroy_crypt_stat(9)
• virt_to_scatterlist(9)
• crypt_scatterlist(9)
• crypt_extent(9)
• ecryptfs_decrypt_page(9)
• ecryptfs_init_crypt_ctx(9)
• ecryptfs_copy_mount_wide_flags_to_inode_flags(9)
• ecryptfs_set_default_crypt_stat_vals(9)
• ecryptfs_new_file_context(9)
• ecryptfs_validate_marker(9)
• ecryptfs_process_flags(9)
• write_ecryptfs_marker(9)
• ecryptfs_code_for_cipher_string(9)
• ecryptfs_cipher_code_to_string(9)
• ecryptfs_write_headers_virt(9)
• ecryptfs_write_metadata(9)
• set_default_header_data(9)
• ecryptfs_read_headers_virt(9)
• ecryptfs_read_xattr_region(9)
• ecryptfs_process_key_cipher(9)
• ecryptfs_destroy_crypto(9)
• ecryptfs_tfm_exists(9)
• ecryptfs_get_tfm_and_mutex_for_cipher_name(9)
• ecryptfs_encode_for_filename(9)
• ecryptfs_decode_from_filename(9)
• ecryptfs_encrypt_and_encode_filename(9)
• ecryptfs_decode_and_decrypt_filename(9)

that's a whole friend group right there, fr fr 🫶 go say hi to all of them.

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aaand that's the page!! ✨ shoutout to /fs/ecryptfs for bringing us this absolute banger, dated October 2026, filed under ecryptfs_encrypt_page(9) 🎀 mwah, go encrypt something, ily bye 💜🧚‍♀️