[Virtio-fs] virtiofsd: sshfs as submount?

[Max Reitz]

On 21.12.20 13:45, Laszlo Ersek wrote:
> 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.

Oh, that makes sense.  Right.

> 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.

Indeed, that works better.

> ... 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!

Er, *cough*, my pleasure! O:)

Max