jbd2_journal_start_reserved(9)

📦 version 7.3.1, in nixpkgs unstable

💅 jbd2_journal_start_reserved(9) — from the Kernel API Manual

okay so bestie, welcome to the glow-up of jbd2_journal_start_reserved, straight outta the Kernel API Manual ✨ she's a little niche but she's iconic, trust.

🎀 NAME

jbd2_journal_start_reserved — start a reserved handle. literally that's her whole job. no cap.

✨ SYNOPSIS

int jbd2_journal_start_reserved (handle_t *handle , unsigned int type ,
       unsigned int line_no );

three args, one int back. she's lowkey low-maintenance like that. 🫶

💖 ARGUMENTS

  • handle — the handle you wanna start, bestie. like, the actual one. 👑
  • type — this one's just for handle statistics. bookkeeping vibes only, she's not out here changing behaviour. 📊
  • line_no — also just for handle statistics. yes queen, log that line number. 🌸

🦋 DESCRIPTION

okay so picture this: you already reserved a handle earlier with jbd2_journal_reserve, right? this function is the part where you finally bring her to life. it attaches handle to the running transaction — or, if there's like, no transaction running at all, it just creates one. main character energy, she makes it happen either way. ⭐

now here's the fun part: unlike jbd2_journal_start, this function cannot block on journal commit, checkpointing, or similar stuff. so no sitting around waiting, she's not about that life. 💅

but — and this is the important bit — it can block on memory allocation or on a frozen journal though. so like, don't get too comfortable. 😭

and the return situation: 0 on success, non-zero on error, and in the error case the handle is freed. so yeah, on error she's gone, don't touch her after that. fr fr. 💀

🌈 SEE ALSO

kernel file ./fs/jbd2/transaction.c, plus the whole friend group:

and that's the page, bestie!! 🧚 from ./fs/jbd2, dated October 2026, filed under jbd2_journal_start_reserved(9) — mwah, go forth and start those reserved handles responsibly 💜🎀

📦 where this page comes from