ubifs_fixup_free_space(9)

📦 version 7.3.1, in nixpkgs unstable

💅 ubifs_fixup_free_space(9) 💅

okay so bestie, welcome to the Kernel API Manual — yes we're reading kernel docs together, this is our bonding time now 🫶

🌸 NAME 🌸

ubifs_fixup_free_space — find & fix all LEBs with free space. literally the cleanup crew of the UBIFS world ✨

🦋 SYNOPSIS 🦋

int ubifs_fixup_free_space (struct ubifs_info *c );

🎀 ARGUMENTS 🎀

  • c — the UBIFS file-system description object. your main character struct, the whole vibe check of the filesystem lives in here 👑

💖 DESCRIPTION 💖

so here's the tea, bestie 🍓 this function fixes up LEBs that contain free space on first mount — but only if the appropriate flag was set back when the FS was created. conditional queen behavior, we love to see it.

every single LEB with one or more empty min. I/O unit (i.e. free-space-count > 0) gets re-written, so we can be absolutely sure the free space is actually erased. no fake-erased nonsense on our watch 💅

and why do we care? because, ngl, this is necessary for some NAND chips 😭 the free space may have been programmed like real "0xff" data (which generates a non-0xff ECC), and that causes future writes to the not-really-erased NAND pages to behave badly. it's giving fake confidence, it's giving not actually erased — and we are NOT here for it 🙈

after the space is fixed up, the superblock flag is cleared, so this whole thing gets skipped for all future mounts. one-and-done, iconic, periodt ✨

🌈 SEE ALSO 🌈

kernel file ./fs/ubifs/sb.c — go read it, it's good for you 🧚

💀 reminder bestie: this whole fixup only happens on first mount, and only if that flag was set at FS creation time. if it wasn't, this function's moment has passed. no cap.

and that's the page! 🎀 brought to you by ./fs/ubifs, dated October 2026, titled ubifs_fixup_free_space(9) — catch you in the next man page, bestie, stay erasing those NAND pages properly 💜🦋⭐

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