jbd2_journa...write_access(9)

📦 version 7.3.1, in nixpkgs unstable

✨ jbd2_journal_get_write_access(9) ✨

okay bestie, welcome to the Kernel API Manual 💅 this one's from the jbd2 corner of the kernel and it's literally the "hey, I'm about to touch this" heads-up for metadata. let's get into it 🫶

🌸 NAME 🌸

jbd2_journal_get_write_access — notify intent to modify a buffer for metadata (not data!!) update 💖

🦋 SYNOPSIS 🦋

int jbd2_journal_get_write_access (handle_t *handle , struct buffer_head
*bh );

like yes the wrapping is kinda unhinged but that's the signature, no cap ✨

🎀 ARGUMENTS 🎀

  • handle — the transaction you're adding these buffer modifications to. it's giving "which tab is this going in" energy 🗂️
  • bh — the bh you're gonna use for metadata writes. the actual buffer head, the main character 💫

⭐ RETURN ⭐

error code, or 0 on success 🎉 (0 = slay, anything else = read the error code, bestie)

🔥 DESCRIPTION 🔥

okay so this is the important bit 🙈 in full data journalling mode the buffer may be of type BJ_AsyncData — and why? because we're "writeing" a buffer which is also part of a shared mapping. yeah, the manpage really does spell it writeing in quotes, i'm not fixing it, i'm just reporting the vibes 💀

so: metadata, not data. don't get it twisted 🧚

🌈 SEE ALSO 🌈

Kernel file ./fs/jbd2/transaction.c — that's where the real lore lives 📖 and the whole jbd2 friend group:

💌 cute lil sign-off: this page lives under ./fs/jbd2 and it's dated October 2026 — yes, the future, we're ahead of schedule, periodt 👑 go forth and get that write access, bestie 💜🦋🌸
📦 where this page comes from