[Pvfs2-developers] pvfs layout

[Sam Lang]

On Jun 20, 2007, at 9:43 PM, Murali Vilayannur wrote:

> Sam,
> Looks great!
> A few minor comments
> - pvfs2-touch.c: leaks io_servers and layout.server_list.servers.

That was just a quick example of how it would be used.  I don't plan  
on committing it and probably should have left it out of the patch.   
Nice catch just the same!

> - instead of sizeof(PVFS_BMI_addr_t), perhaps we can have sizeof 
> (*io_servers)?

Is the type going to change ever?

> - sys-create.sm: seems to leak  sm_p- 
> >u.create.layout.server_list.servers?

Also a nice catch.  I've fixed this in my working version.

> - I forget if these qhash_search(PINT_fsid_config_cache_table)
> required a spinlock to serialize searches or if this a purely
> client-side only code with no race conditions possible?
> in pint_cached_config_*()

I think that one is ok.

> - ANy thoughts on how client-core/vfs apps should make use of the
> additional layout information? Another Extended attributes on parent
> directory perhaps?

Maybe.  Would a layout dir hint be something the VFS users would  
use?  I had thought that this would be for users of our interfaces only.

>
> Perhaps we could start versioning system interface function  
> definitions
> and have callers specify the version they are interested in?
> something like callers have to #define PVFS_USE_VERSION before
> including the pvfs.h header file.
>
> #ifndef PVFS_USE_VERSION
> #define PVFS_USE_VERSION  CURRENT_VER
> #endif
>
> #if PVFS_USE_VERSION  < CURRENT_VER
> #define PVFS_sys_create(x,y,z) PVFS_sys_create_layout(x, y, z, NULL)
> #endif
>
> I am sure you guys would have thought of something along this, but
> just wanted to doc it here in case :)

I'm not crazy about making users specify a version like that.  I'd  
rather just change the interfaces as little as possible, and where  
necessary make the change and have users handle it themselves.

Thanks for the comments!

-sam


> thanks,
> Murali
>
>
> On 6/20/07, Sam Lang <slang at mcs.anl.gov> wrote:
>>
>> On Jun 20, 2007, at 5:56 PM, Robert Latham wrote:
>>
>> > On Wed, Jun 20, 2007 at 05:05:30PM -0500, Sam Lang wrote:
>> >> Let me know what you think.
>> >
>> > My only concern is keeping ROMIO in sync.  But what's one more
>> > autoconf macro?
>>
>> Its a PITA, is what it is.  Rob and I talked about defining a new
>> PVFS_sys_create_layout function that would take a layout parameter,
>> leaving PVFS_sys_create untouched.  If ROMIO is going to be one of
>> the users of the layout structure, that may not make a lot of sense
>> though, and it seems messy.  With the latest PVFS FUSE port, maybe
>> there are more layers that have system interface deps, so we should
>> consider the potential impact there as well.
>>
>> -sam
>>
>> >
>> > ==rob
>> >
>> > --
>> > Rob Latham
>> > Mathematics and Computer Science Division    A215 0178 EA2D B059  
>> 8CDF
>> > Argonne National Lab, IL USA                 B29D F333 664A 4280  
>> 315B
>> >
>>
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>