Re: [PATCH 2/8] xfstests: add regression test for kernel bz 60673

Eric Sandeen
2013-10-21T15:21:48Z

On 10/21/13 10:14 AM, Eric Sandeen wrote:
> On 10/21/13 10:09 AM, Josef Bacik wrote:
>> On Mon, Oct 21, 2013 at 10:03:10AM -0500, Eric Sandeen wrote:
>>>> On 10/18/13 1:26 PM, Josef Bacik wrote:
>>>>>> There was a problem with send trying to overwrite a file that wasn't actually
>>>>>> the same. This is a test to check this particular case where receive fails when
>>>>>> it should succeed properly. I tested this to verify it fails without my fix and
>>>>>> passes with my fix. Thanks,
>>>>
>>>> 2 things -
>>>>
>>>> Why does the selinux context break things? That seems like a problem w/ send
>>>> if it can't work on a context-mounted fs? (disabling it for now doesn't bother
>>>> me, but I'm surprised that it's required).
>>>>
>> So it is the context that xfstests is using, not contexts itself. Xfstests is
>> using the nfs context, and using selinux contexts intercepts all getxattr calls,
>> so when send tries to copy the xattrs for the file it calls getxattr, and
>> because we are using the nfs context it returns EOPNOTSUPP from selinux, it
>> never makes it down to btrfs. When using the actual real context it works fine
>> because it calls down into the file system.
>>
>
> This still sounds weird. Is btrfs send trying to copy the selinux attrs directly?
>
> Shouldn't they be skipped, and be left up to the receiving end to set the selinux
> xattrs (or not) per the policy for the destination?

Eh, ok, Josef pointed out that "cp -a" does exactly the same thing.

So I'll retract the concern & go learn more about selinux. ;)

-Eric