[Unionfs] Can't make branch read only

[Olivier Blin]

Erez Zadok <ezk at cs.sunysb.edu> writes:

> In message <200710231821.22948.herton at mandriva.com.br>, Herton Ronaldo Krzesinski writes:
>> Em Tuesday 23 October 2007 18:02:26 Herton Ronaldo Krzesinski escreveu:
>> > Em Tuesday 23 October 2007 16:13:40 Olivier Blin escreveu:
>> > > Actually, the "mount -t unionfs -o remount,mode=/live/foo=ro none
>> > > /live/union" command succeeds, with no error message, and nothing in
>> > > syslog.
>> >
>> > Yes. And debugging here what happens in this case is that
>> > unionfs_remount_fs is called with options NULL, so the "goto out_error"
>> > early in the function triggers, and do_remount_mode_option isn't even
>> > executed.
>> 
>> Confirmed, the problem is "mode" option, it falls in "VFS took care of it" 
>> case, doing this:
>> 
>> --- fs/unionfs/super.c.orig	2007-10-23 18:10:15.000000000 -0200
>> +++ fs/unionfs/super.c	2007-10-23 18:10:36.000000000 -0200
>> @@ -626,7 +626,7 @@ static int unionfs_remount_fs(struct sup
>>  			new_branches--;
>>  			continue;
>>  		}
>> -		if (!strcmp("mode", optname)) {
>> +		if (!strcmp("mode_", optname)) {
>>  			err = do_remount_mode_option(optarg, new_branches,
>>  						     tmp_data,
>>  						     tmp_lower_paths);
>
> Herton, what kernel are you using that refuses to pass the mode option to
> unionfs?  Is this a vanilla kernel or a modified one?  if it's a modified
> one (mandriva?), can you point me to kernel sources please so I can check
> them out.  I'm unable to reproduce your bug with my vanilla kernels: the
> mode option is passed just fine to unionfs.

Hi,

It's 2.6.22.9 with the following patches applied:
http://svn.mandriva.com/svn/packages/cooker/kernel-2.6/current/PATCHES/patches/
Maybe AppArmor-related?

Thanks

-- 
Olivier Blin (blino) - Mandriva