UML mount failure with Linux 6.11

[Karel Zak]

On Wed, Nov 27, 2024 at 09:26:46AM GMT, Hongbo Li wrote:
> 
> 
> On 2024/11/26 21:50, Johannes Berg wrote:
> > On Mon, 2024-11-25 at 18:43 +0100, Karel Zak wrote:
> > > 
> > > The long-term solution would be to clean up hostfs and use named
> > > variables, such as "mount -t hostfs none -o 'path="/home/hostfs"'.
> > 
> > That's what Hongbo's commit *did*, afaict, but it is a regression.
> > 
> > Now most of the regression is that with fsconfig() call it was no longer
> > possible to specify a bare folder, and then we got discussing what
> > happens if the folder name actually contains a comma...
> > 
> > But this is still a regression, so we need to figure out what to do
> > short term?
> > 
> So for short term, even long term, can we consider handling the hostfs
> situation specially within libmount?

Yes (see reply to Johannes ).

> Such as treat the whole option as one
> key(also may be with comma, even with equal)

There could be userspace specific options, VFS flags, etc.

  -o /home/hostfs,ro,noexec

Is it one path or path and two options?

> in this case, libmount will
> use it as FSCONFIG_SET_FLAG. We can do that because for hostfs, it only has
> one mount option, and no need for extension.

We can automatically add a key (e.g. hostfs=) and use FSCONFIG_SET_FLAG.
The goal should be to get the path as a value, because key is limited to
256 bytes.

    Karel

-- 
 Karel Zak  <kzak at redhat.com>
 http://karelzak.blogspot.com