Re: Bug#801527: mount believes correctly-formatted UDF uid=forget option is in error

Re: Bug#801527: mount believes correctly-formatted UDF uid=forget option is in error

[Andreas Henriksson]

Control: tags -1 + upstream

Hello Anthony DeRobertis.

Thanks for your bug report.

On Sun, Oct 11, 2015 at 01:27:12PM -0400, Anthony DeRobertis wrote:
> Package: mount
> Version: 2.27-3
> Severity: important
> 
> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA1
> 
> I recently upgraded a system to Jessie (from Wheezy), and mounting UDF
> filesystems broke. I confirmed the bug still exists on the machine I'm
> reporting from (which runs testing/unstable).

Jessie and onwards uses a new mount implementation based on libmount.

> 
> It appears mount has decided that "uid=ignore", "uid=forget",
> "gid=ignore", and "gid=forget" are invalid mount options. Instead of
> passing them to the kernel as it used to, it now prints "mount: failed
> to parse mount options"

Using LIBMOUNT_DEBUG=all mount -t udf -o uid=ignore,gid=forget ...
shows the following message (among others):

24171: libmount:    UTILS: cannot convert 'ignore' username to UID

... and according to the following code you seem to be very right
that except an actual uid you can also pass 'uid=ignore' or
'uid=forget' explicitly:

https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/fs/udf/super.c#n352

I see several possible options for implementing this in the future:
 - special-case 'ignore' and 'forget' and pass those as is.
 - if uid-lookup fails, try the above.
 - (assuming different filesystems have different special options)
   let any fs-option through as-is if 'smart lookup' fails.
 - ...

I'm adding the upstream mailing list to CC in the hope that someone
has a suggestion on how to best handle this case.


> 
> busybox mount works fine, so the kernel is still happy with the options.
> And even in 4.2, they're still documented in
> Documentation/filesystems/udf.txt, so they should work.

Thanks for the extra data point.


Regards,
Andreas Henriksson

Re: Bug#801527: mount believes correctly-formatted UDF uid=forget option is in error

[Karel Zak]

On Sun, Oct 11, 2015 at 10:58:48PM +0200, Andreas Henriksson wrote:
> Using LIBMOUNT_DEBUG=all mount -t udf -o uid=ignore,gid=forget ...
> shows the following message (among others):
> 
> 24171: libmount:    UTILS: cannot convert 'ignore' username to UID
> 
> ... and according to the following code you seem to be very right
> that except an actual uid you can also pass 'uid=ignore' or
> 'uid=forget' explicitly:
> 
> https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/fs/udf/super.c#n352
> 
> I see several possible options for implementing this in the future:
>  - special-case 'ignore' and 'forget' and pass those as is.
>  - if uid-lookup fails, try the above.
>  - (assuming different filesystems have different special options)
>    let any fs-option through as-is if 'smart lookup' fails.

This is the way how the original mount(8) has worked. Fixed:

 https://github.com/karelzak/util-linux/commit/440a355a3d3934d99f7ef82adf02342e6f2f7983

will be in v2.27.1.

Thanks!
    Karel

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