STRUCT UBI_FM_HDR(9)

👑 STRUCT UBI_FM_HDR(9) 👑

okay bestie, so this page is from the Kernel API Manual and it's literally the receipts for one very specific little thing: struct ubi_fm_hdr, which is the header of the fastmap data set. that's it, that's the whole vibe. she's the opening act, the cover page, the "hi bestie welcome to the fastmap" moment ✨

🌸 SYNOPSIS 🌸

here's her whole entire shape, no notes, copy it exactly:

struct ubi_fm_hdr {
    __be32 magic;
    __be32 free_peb_count;
    __be32 used_peb_count;
    __be32 scrub_peb_count;
    __be32 bad_peb_count;
    __be32 erase_peb_count;
    __be32 vol_count;
    __u8 padding[4];
 };

like yes she's small but she's doing SO much 💅

🎀 MEMBERS 🎀

• magic — the fastmap header magic number (UBI_FM_HDR_MAGIC). her little signature, her name tag at the party 🫶
• free_peb_count — how many free PEBs this fastmap knows about. the available ones, the chill ones, the "come thru" ones 🦋
• used_peb_count — how many used PEBs this fastmap knows about. taken. occupied. booked and busy 😭
• scrub_peb_count — how many PEBs are to be scrubbed, according to this fastmap. they need a lil self-care moment 🧖
• bad_peb_count — how many bad PEBs this fastmap knows about. not their fault, they're just going through it 💀
• erase_peb_count — the number of bad PEBs which have to be erased. yes, that's what it says, that's exactly what it says, no I'm not paraphrasing 🙈
• vol_count — how many UBI volumes this fastmap knows about. the whole friend group, counted 👑

ok real talk: every single one of these is a __be32 except the last field, padding, which is __u8 padding[4] — that one's just there filling space and honestly same girlie, same 🎀

💖 SEE ALSO 💖

• Kernel file ./drivers/mtd/ubi/ubi-media.h
• struct ubi_ec_hdr(9)
• struct ubi_vid_hdr(9)
• struct ubi_vtbl_record(9)
• struct ubi_fm_sb(9)
• struct ubi_fm_scan_pool(9)
• struct ubi_fm_ec(9)
• struct ubi_fm_volhdr(9)
• struct ubi_fm_eba(9)

like she has a whole extended universe of structs, go read them, they all ate 🔥

k bye bestie, this page lives in ./drivers/mtd/ubi, dated October 2026, and it's filed under struct ubi_fm_hdr(9) — that's the whole thing, mwah 💋🌈⭐