Re: [vserver] ext4 inode tagging

Roberto Puzzanghera wrote:
>>> <snip>
>>> Unfortunately, while apparently inode tagging and disk limits
>>> were working fine, I observed that when I bind mount a host
>>> directory inside a running guest I lose all read priviledges
>>> related to *newly* created files (I mean files created *after*
>>> the inode tagging).
>>
>> hmm? not sure what you are trying to tell us here ...
>
> I am mounting a host's directory inside the guest as follows inside fstab
>
> /vservers/test2/usr/local/shared_dir /shared none bind 0 0
>
> When I create a new file inside /vservers/test2/usr/local/shared_dir I
> don't have the read priviledges inside the guest.

"The guest" referring to a guest other than test2, right?

>>> I solved simply rebooting without the tag mount flag. And the
>>> shared files, created with the tag flag on, now have strange
>>> owners:
>>
>>> -rw-r--r-- 1 50333648 3892314192 6 Jan 15 16:41 test.html
>>
>> which is the expected result with your tagging (ID24)
>> i.e. the upper uid/gid bits have been used for storing
>> the xid, for example, 50333648 = 30007D0(hex) which
>> is 0x03 (xid part) and 0x7D0 (uid part), similar for
>> the gid ...
>>
>> the best way to 'fix' this is to turn tagging back on
>> and the remove the xid from all affected files. after
>> that you can turn it off and all uid/gid will be fine
>
> Thanks, but I have already solved manually.
>
> Anyway, it's not clear to me if is there a chance to have both tags and
> bind mount working..

There is. Depending on what it is you want to achieve, you have two
ways to go about it. Number one is the option notagcheck, which
tags all files, but doesn't use tags as an access restriction. This
is what you want if you still want to have disk limits apply to the
two guests separately.

Number two is setting the two guests to use the same tag. That would
mean you can't limit them separately, but you can still use tags
for access restrictions between those guests and others. This would
be accomplished by setting /etc/vservers/<guest>/tag to the same
value (e.g. one of the xids).

-- 
Daniel Hokka Zakrisson