Re: [NFS] blocks of zeros (NULLs) in NFS files in kernels >= 2.6.20

[Chuck Lever]

On Sep 5, 2008, at Sep 5, 2008, 4:04 PM, Aaron Straus wrote:
> Hi,
>
> On Sep 05 03:56 PM, Chuck Lever wrote:
> > [ replacing cc: nfs@xxxxxx with linux-nfs@xxxxxxxxxxxxxxx, and neil's
> > old address with his current one ]
>
> Sorry I probably grabbed an old MAINTAINERS file.
>
> > On Sep 5, 2008, at Sep 5, 2008, 3:19 PM, Aaron Straus wrote:
> > > Writer_Version     Outcome:
> > > <= 2.6.19          OK
> > > > = 2.6.20	    BAD
> >
> > Up to which kernel?  Recent ones may address this issue already.
>
> BAD up to 2.6.27-rc?
>
> I have to see exactly which is the last rc version I tested.
>
> > > I can try to bisect between 2.6.19 <-> 2.6.20.
> >
> > That's a good start.
>
> OK will try to bisect.
>
> > Comparing a wire trace with strace output, starting with the writing
> > client, might also be illuminating.  We prefer wireshark as it uses
> > good default trace settings, parses the wire bytes and displays them
> > coherently, and allows you to sort the frames in various useful ways.
>
> OK.  Could you also try to reproduce on your side using those python
> programs?  I want to make sure it's not something specific with our
> mounts, etc.

I have the latest Fedora 9 kernels on two clients, mounting via NFSv3  
using "actimeo=600" (for other reasons).  The server is OpenSolaris  
2008.5.

reader.py reported zeroes in the test file after about 5 minutes.

Looking at the file a little later, I don't see any problems with it.

Since your scripts are not using any kind of serialization (ie file  
locking) between the clients, I wonder if non-determinant behavior is  
to be expected.

--
Chuck Lever
chuck[dot]lever[at]oracle[dot]com
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/