Feature Request: Hide the fsck /tmp mount

[pmagid]

Assume you are trying to mount and open your encrypted archive only when egressing or ingressing files for security.
Now assume your archive is very large and if you do a fsck it will take days or weeks.

While you are doing the fsck currently your archive is visible (and available) when doing a df for example:
/your/archive/location 100T 90T 10T 99% /tmp/gocryptfs.fsck.12345678

I dont have a solution, but if you could hide the mount from showing up in df that would be good. If you can do the fsck without making the entire volume available to processes other than the fsck process that would be even better.

[rfjakob]

Good idea.

[sauravrao637]

I looked into it, and I think we could create a private mount namespace specifically for -fsck, make its mount propagation private, and create the temporary FUSE mount inside it. This should keep the plaintext mount out of the parent mount namespace while fsck is running.

The main concern is permissions: creating a mount namespace and changing its propagation normally require CAP_SYS_ADMIN. Could that be an issue for users running -fsck without elevated privileges?