layout_commit(9)

✨ layout_commit(9) ✨

okay so bestie, buckle up — this is layout_commit, from the Kernel API Manual, and she's literally the one who figures out where your index nodes go before commit 💅

---

🎀 NAME 🎀

layout_commit — determine positions of index nodes to commit.

like, she does the seating chart for the index nodes before the commit party 🪑✨

---

💖 SYNOPSIS 💖

int layout_commit (struct ubifs_info *c , int no_space , int cnt );

---

🌸 ARGUMENTS 🌸

• c — the UBIFS file-system description object 🦋 (yes, the whole file-system's little description bestie)
• no_space — this one flags that insufficient empty LEBs were allocated 😭 like the allocation didn't get enough empty LEBs
• cnt — number of znodes to commit, fr fr

---

💫 DESCRIPTION 💫

So the job here is: calculate and update the positions of index nodes to commit. That's it, that's the vibe 👑

But here's the plot twist: if there were an insufficient number of empty LEBs allocated, then the index nodes get placed into the gaps created by obsolete index nodes in non-empty index LEBs 🫶 For this purpose, an obsolete index node is one that was not in the index as at the end of the last commit. No cap — that's the definition, don't come for me.

And to write "in-the-gaps" requires that those index LEBs are updated atomically in-place 🔥 that's a whole requirement, not a suggestion, so keep it in mind iykyk

---

🦋 SEE ALSO 🦋

Kernel file ./fs/ubifs/tnc_commit.c — plus the whole friend group:

• make_idx_node(9)
• fill_gap(9)
• find_old_idx(9)
• is_idx_node_in_use(9)
• layout_leb_in_gaps(9)
• get_leb_cnt(9)
• layout_in_gaps(9)
• layout_in_empty_space(9)
• find_first_dirty(9)
• find_next_dirty(9)
• get_znodes_to_commit(9)
• alloc_idx_lebs(9)
• free_unused_idx_lebs(9)
• free_idx_lebs(9)
• ubifs_tnc_start_commit(9)
• write_index(9)
• free_obsolete_znodes(9)
• return_gap_lebs(9)
• ubifs_tnc_end_commit(9)

---

and that's the whole page, bestie 🧚💜 shoutout to ./fs/ubifs for the source, and this one's stamped October 2026, page layout_commit(9) — periodt 🌈⭐