Re: virtiofsd: sshfs as submount?

[Laszlo Ersek]

On 12/21/20 13:06, Max Reitz wrote:

> I can share sshfs through sshfs, so it must be something virtiofs-specific.

Your insight proved crucial to solving the riddle.

Chaining sshfs with sshfs made me think that you must have used a normal
(non-root) user account on the first remote computer (where you ran the
2nd sshfs command).

And that reminded me of the "allow_root" option which I seemed to have
read somewhere around the FUSE manuals.

So indeed I set up another sshfs mount on my laptop, with my normal UID,
and tried to access the mount point from a plain root shell (with
virtiofsd completely out of the picture) -- it failed with "Permission
denied". :) It's apparently intentional on sshfs's / FUSE's part, to
protect the local root user from "remote nastiness injection".

Then I re-did the sshfs mount, but with "-o allow_root" this time. The
plain root shell can now access the mount point.

... So can virtiofsd :) It's *amazing* to see remote files in the UEFI
shell. I never thought "filesystem as a service" could feel this empowering.

Thanks, Max!
Laszlo