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

[William A. (Andy) Adamson]

On 11/28/07, Dean Hildebrand <seattleplus at gmail.com> wrote:
>
>
> > 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?


some of the same issues as with the 2.6.18.3 kernel - especially on the
failure paths.
the new kernel nfs client is quite different, and we need to re-think pnfs.c.
Specifically, all the tests
we have to decide if we are using pnfs or regular nfs. functions like
pnfs_use_read/write(),  pnfs_use_ds_io(),pnfs_use_nfsv4_rproto(), etc.

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?


It's a mix of the two -  as Benny suggested we don't want to change
everything at once.
Please pour over the patches - Benny has already found mistakes.

-->Andy


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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> > pNFS at linux-nfs.org
> > http://linux-nfs.org/cgi-bin/mailman/listinfo/pnfs
>
>
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