[pnfs] [PATCH 0/20] linux-pnfs-2.6-latest pNFS client read I/O - Draft 13

[Dean Hildebrand]

> There are a lot of issues with the code that can be addressed, as 
> Benny suggested, after we port forward.
>
Thanks for the refactoring.  I haven't had time to go through the 
patches yet, but what types of issues are you referring to? The same 
issues as with the 2.6.18 kernel?

I guess my question relates to how closely I should review the patches.  
If the patches are based more or less on the 2.6.18 pnfs code, then I'm 
happy if your tests pass, but if this is supposed to be closer to the 
real thing, then maybe we should all pour over the patches a little 
closer as it will be a model for moving the remaining parts of the code 
forward.  Maybe a mix of the two? 

Thanks
Dean

> I will test against the 2.6.24-rc2 kernel once the GPFS cluster is 
> updated.
>
> With these patches, the 2.6.24-rc3 pNFS filelayout client uses normal 
> NFSv4.1 for write I/O and pNFS for read I/O. GETDEVICELIST, 
> GETDEVICEINFO, LAYOUTGET, LAYOUTRETURN are implemented. Data server 
> sessions and session recovery is implemented. Renwal of state is 
> turned off because it's implementation is incomplete - so session 
> recovery is tested!
>
> The 2.6.18.3 <http://2.6.18.3> client implemented three I/O paths:
>
> 1) Use NFS page cache with RPC (file layout)
> 2) Use NFS page cache with NO RPC (object and block layout)
> 3) Do not use NFS page cache, and of course, no RPC. (PVFS2, the 
> non-filelayout version).
>
> This patch set implements the first two I/O paths, which in the new 
> kernel goes through nfs_readpages to pnfs_readpages.
> The third I/O path jumps out of the NFS I/O path in pnfs_file_read, 
> and is therefore implemented, but not tested.
>
> Fred has "smoke tested" path #2 with our block layout driver against 
> the pynfs pNFS block server. He can mount/umount, read, close. Benny 
> will have to really test this path with the object layout backend.
>
> I added these CITI October bakeathon patches to three 2.6.18.3 
> <http://2.6.18.3> servers on the CITI GPFS.
> - fix xdr encoding of CREATE_SESSION result
> - server_draft13_update
>
> The MDS lease time is 20 seconds, very short to test the session 
> recovery code. 2 Data Servers were available.
>
> The 2.6.24-rc3 client passed:
>
> Connectathon
> - basic test
> - general test - sometimes. when it fails, the MDS dies on close.
> - special test upto truncate where the MDS died on close.
> - the lock tests were not tried.
>
> Not the best news - but I suspect that I am missing some 2.6.18.3 
> <http://2.6.18.3> server patches.
>
> Cat of a large file (16688923 Nov 28 10:36 messages) large enough to 
> use 3-4 stripes for session recover to be required prior to 
> layoutreturn when client printk's are fully turned on)
>
> So, it is not perfect, but it does perform the read I/O path. Please 
> look it over.
>
> Thanks
>
> -->Andy
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