bdev_freeze(9)

📦 version 7.3.1, in nixpkgs unstable

💅 bdev_freeze — the bdev_freeze(9) era 💅

okay so bestie, welcome to the Kernel API Manual entry for bdev_freeze — like, the lock-your-filesystem-down-and-make-it-actually-consistent girlie of the block layer 🎀

✨ NAME ✨

bdev_freeze — lock a filesystem and force it into a consistent state

✨ SYNOPSIS ✨

int bdev_freeze (struct block_device *bdev );

✨ ARGUMENTS ✨

  • bdev — the blockdevice to lock 🦋 (yes, that's the whole assigned job, she's booked and busy)

💖 DESCRIPTION 💖

okay so here's the tea ☕ — if a superblock is found on this device, we take the s_umount semaphore on it to make sure literally nobody unmounts until the snapshot creation is done. no cap, that's the whole point.

and the reference counter, bd_fsfreeze_count? she's the main character guaranteeing that only the last unfreeze process can actually unfreeze the frozen filesystem when multiple freeze requests arrive simultaneously 🔥 the way she works: she counts up in bdev_freeze and counts down in bdev_thaw. and when she hits 0, thaw_bdev will unfreeze for real for real 💀

ngl the counter is doing a lot of heavy lifting here — don't sleep on her 🙈

🌈 RETURN 🌈

On success zero is returned, and on failure a negative error code — that's it, that's the vibe check ⭐

👑 SEE ALSO 👑

Kernel file ./block/bdev.c — and honestly the whole squad, periodt:

🫶 and that's a wrap, bestie — this page came to you straight from ./block, dated October 2026, and it ate fr fr 💅✨

📦 where this page comes from