invalidate_fastmap(9)

💅 invalidate_fastmap(9) — a Kernel API Manual moment

okay bestie, welcome to invalidate_fastmap(9), a page straight out of the Kernel API Manual and honestly? it's giving "small function, big consequences" ✨

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🌸 NAME 🌸

invalidate_fastmap — destroys a fastmap. that's it. that's the whole vibe. lowkey ominous, highkey necessary 🫶

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🦋 SYNOPSIS 🦋

int invalidate_fastmap (struct ubi_device *ubi );

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🎀 ARGUMENTS 🎀

• ubi — the UBI device object. yes, THE device object. the main character here, no cap 👑

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✨ DESCRIPTION ✨

so here's the tea ☕ — this function makes sure that on the next UBI attach, a full scan gets issued. like, a whole entire scan. no shortcuts, no skipping ahead, we're doing the work fr fr.

why would you ever want that? because sometimes UBI is about to write a new fastmap and it literally cannot do it 😭 and when that happens, you've got exactly two options, bestie:

1. make sure the current fastmap won't get used at attach time, then just keep going, or
2. fall back to RO mode so the current fastmap stays in a valid state.

either way, the situation is handled. slay 💅

return value check: returns 0 on success. anything < 0 means an internal error — i.e. something went wrong inside and you should be concerned 🙈

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💖 SEE ALSO 💖

the whole friend group 🫶 — all of these live in the kernel file ./drivers/mtd/ubi/fastmap.c:

• init_seen(9)
• free_seen(9)
• set_seen(9)
• self_check_seen(9)
• ubi_calc_fm_size(9)
• new_fm_vbuf(9)
• add_aeb(9)
• add_vol(9)
• assign_aeb_to_av(9)
• update_vol(9)
• process_pool_aeb(9)
• unmap_peb(9)
• scan_pool(9)
• count_fastmap_pebs(9)
• ubi_attach_fastmap(9)
• find_fm_anchor(9)
• ubi_scan_fastmap(9)
• ubi_write_fastmap(9)
• return_fm_pebs(9)
• ubi_update_fastmap(9)

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ngl if you're reading this page you're probably deep in flash translation layer business, and honestly? respect. 🧚

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and that's the whole page, babe! 💜 born from ./drivers/mtd/ubi, dated October 2026 — catch you on the next attach, mwah 🍓