[Gluster-devel] Mark all the xlator fops 'static '

[Jiffin Tony Thottan]

On 31/07/15 19:29, Kaleb S. KEITHLEY wrote:
> On 07/30/2015 05:16 PM, Niels de Vos wrote:
>> On Thu, Jul 30, 2015 at 08:27:15PM +0530, Soumya Koduri wrote:
>>> Hi,
>>>
>>> With the applications using and loading different libraries, the function
>>> symbols with the same name may get resolved incorrectly depending on the
>>> order in which those libraries get dynamically loaded.
>>>
>>> Recently we have seen an issue with 'snapview-client' xlator lookup fop -
>>> 'svc_lookup' which matched with one of the routines provided by libntirpc,
>>> used by NFS-Ganesha. More details are in [1], [2].
>> Indeed, the problem seems to be caused in an execution flow like this:
>>
>> 1. nfs-ganesha main binary starts
>> 2. the dynamic linker loads libntirpc (and others)
>> 3. the dynamic linker retrieves symbols from the libntirpc (and others)
>> 4. 'svc_lookup' is amoung the symbols added to a lookup table (or such)
>> 5. during execution, ganesha loads plugins with dlopen()
>> 6. the fsalgluster.so plugin is linked against libgfapi and gfapi gets
>>     loaded
>> 7. libgfapi retrieves the .vol file and loads the xlators, including
>>     snapview-client
>> 8. snapview-client provices a 'svc_lookup' symbol, same name as
>>     libntirpc provides, complete different functionality
> So far so good. But I would have expected the compiler to have populated
> the function pointers in snapview-client's fops table at compile time;
> the dynamic loader should not have been needed to resolve
> snapview-client's svc_lookup, because it was (should have been) already
> resolved at compile time.
>
> And in fact it is, but, there are semantics for global (.globl) symbols
> and run-time linkage that are biting us.
>
>

Hi all,

I am hitting a similar type of collision on ganesha 2.4.  In ganesha 
2.4, we introduced stackable
mdcache at top of every FSAL. The lookup(mdc_lookup) function has 
similar signature to gluster
mdcache lookup fop. In my case ganesha always pick up mdc_lookup from 
its layer not from
gfapi graph. When I disabled md-cache it worked perfectly. As Soumya 
suggested before do we
need to change every xlator fop to static?

Regards,
Jiffin