check_free_space(9)

💅 check_free_space — the manual page bestie, but make it iconic

okay so real talk: the manual name for this one is check_free_space(9) — it's a section 9 kernel API page, the kind of thing you read when you're deep in the UBIFS trenches at 2am and your brain is lowkey fried. anyway. let's get into it 🫶

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✨ NAME ✨

check_free_space — the vibe check for free space before you mount. literally just "is there enough room in here or not" 💖

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🌸 SYNOPSIS 🌸

int check_free_space (struct ubifs_info *c );

that's it. that's the whole call. one argument, one int, no drama 💅

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🎀 ARGUMENTS 🎀

• c — the UBIFS file-system description object. yes bestie, that one. it's the struct that knows everything about your file system 💜

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🦋 DESCRIPTION 🦋

so what does it do? okay so basically this function makes sure UBIFS has enough free space to be mounted in read/write mode. that's the whole assignment. that's the job. 🫶

and why does it matter? because UBIFS must always have some free space to allow deletions. like, always. no cap. deletion needs room too, which is giving "you have to spend space to reclaim space" and honestly? iconic logic 😭

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👑 SEE ALSO 👑

the whole friend group — all of these live in the kernel file ./fs/ubifs/super.c and honestly you should go say hi to all of them:

• validate_inode(9)
• init_constants_early(9)
• bud_wbuf_callback(9)
• take_gc_lnum(9)
• alloc_wbufs(9)
• free_wbufs(9)
• free_orphans(9)
• free_buds(9)
• check_volume_empty(9)
• ubifs_parse_param(9)
• destroy_journal(9)
• bu_init(9)
• mount_ubifs(9)
• ubifs_umount(9)
• ubifs_remount_rw(9)
• ubifs_remount_ro(9)
• open_ubi(9)

and they all live under ./fs/ubifs in case you were wondering 🧚

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okay that's the page!! and for the cute sign-off: this whole thing comes from ./fs/ubifs, dated October 2026, and it's filed under check_free_space(9) in the Kernel API Manual. slay, go mount something responsibly 🔥💖