fs_bdev_unregister(9)

🦋 fs_bdev_unregister — ok so this is the breakup function, bestie

no cap, it literally just drops a superblock's claim on a block device. that's the whole vibe.

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✨ SYNOPSIS ✨

void fs_bdev_unregister (struct file *bdev_file , struct super_block *sb );

like, void, so it gives you nothing back. it just takes. iconic behavior honestly 💅

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🎀 ARGUMENTS 🎀

• bdev_file — the file you got back from fs_bdev_file_open_by_{dev,path}(). yes that one. don't just hand over a random file, we're not animals 🫶
• sb — the superblock that this device was claimed for. the whole reason we're here.

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🌸 DESCRIPTION 🌸

okay so picture this: it's the literal inverse of fs_bdev_register. the way that it works is you drop one claim on the {dev, sb} entry — yes, just one, it's not greedy — and the last claim is the one that actually unregisters it. also important: if there's a pinning cursor hanging around, the actual unlink gets deferred. it's giving "i'll get to it later" energy 😭

the big thing: this does not close the device. not even a little. so if you're a caller who has to do stuff with the still-open device between unregistering and closing — think re-allowing freezing on one that got denied for a membership change — you pair this with bdev_fput. that's the combo move, iykyk 🔥

and if you just want the normal "unregister AND close" situation? that's fs_bdev_file_release, the common one. she's the everyday queen 👑

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💜 SEE ALSO 💜

everything else in the superblock cinematic universe, fr fr — Kernel file ./fs/super.c:

• super_lock(9)
• alloc_super(9)
• deactivate_locked_super(9)
• deactivate_super(9)
• grab_super(9)
• retire_super(9)
• generic_shutdown_super(9)
• sget_fc(9)
• iterate_supers_type(9)
• reconfigure_super(9)
• emergency_thaw_all(9)
• get_anon_bdev(9)
• sget_dev(9)
• fs_bdev_freeze(9)
• fs_bdev_thaw(9)
• fs_bdev_file_open_by_dev(9)
• fs_bdev_file_open_by_path(9)
• fs_bdev_file_release(9)
• get_tree_bdev_flags(9)
• get_tree_bdev(9)
• vfs_get_tree(9)
• sb_wait_write(9)
• freeze_super(9)
• thaw_super(9)

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ok that's the whole page 💖 go forth and unregister responsibly, and remember: don't close the device, that's somebody else's job 🧚

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✿ this lil masterpiece lives in ./fs ✿ and it's dated October 2026 — yes we're being time travellers about it, slay ⭐🎀