thaw_super(9)

📦 version 7.3.1, in nixpkgs unstable

💖 thaw_super — unlock the filesystem, bestie 💖

Okay so real talk: this is thaw_super from the Kernel API Manual — the literal glow-up page for <hotpink>thaw_super(9)</hotpink>. It's the un-freeze. The defrost. The "we're so back" moment for a filesystem that got iced. 🧊➡️🔥

✨ SYNOPSIS ✨

int thaw_super (struct super_block *sb , enum freeze_holder who , const
void *freeze_owner );

Yes bestie, that's the whole signature — three args, one int return, no cap. 💅

🫶 ARGUMENTS 🫶

  • sb — the super to thaw. Like, the actual super_block we're bringing back to life. 🌸
  • who — the context that wants to freeze. Yep, the freeze-holder vibe check. 👀
  • freeze_owner — the owner of the freeze. Gotta know whose freeze this is, fr fr. 🎀

🦋 DESCRIPTION 🦋

So here's the tea: this unlocks the filesystem and marks it writeable again after freeze_super, if there are no remaining freezes on the filesystem. Key word: if. Don't come for me if you skipped that part. 😭

The who argument should be:

  • FREEZE_HOLDER_USERSPACE — if userspace wants to thaw the fs; 💖
  • FREEZE_HOLDER_KERNEL — if the kernel wants to thaw the fs. 💜
  • FREEZE_MAY_NEST — whether nesting freeze and thaw requests is allowed. 🪆✨

And here's the part that lowkey matters a lot: a filesystem may hold multiple devices, and thus a filesystem may have been frozen through the block layer via multiple block devices. The filesystem remains frozen until all block devices are unfrozen. All of them. Every single one. No partial slay. 👑

So if you thaw one device and think you're done? Not me being the bearer of bad news, but nope — she stays frozen until the whole squad is unfrozen. 🧊🫶

🌈 SEE ALSO 🌈

Kernel file ./fs/super.c — plus the whole friend group:

Okay that's the whole page, bestie — go thaw something responsibly. 💅✨ This lil writeup lives in ./fs, dated October 2026, and it's the thaw_super(9) entry, mwah 💋🎀

📦 where this page comes from