Short-reads on NFS client

Short-reads on NFS client

[Shehjar Tikoo]

Hi All

Is there ever a possibility that a read syscall over linux nfs client
will return a short read? I think a short read is what I am observing
on our system with unfs3 as the NFS server. I've instrumented the
server and it seems to be returning the correct amount of data.

Is there any way I can debug this further?

I am running the  2.6.18-92.el5 kernel. The tool I am using is fileop
that is part of the iozone package. The original problem with the test
is that it outputs "Data mis-compare" error messages which means that
while doing a byte-to-byte comparison of what it wrote against the
data it read back from the file, it fails to see same contents as
written by it. On further hacking a bit with the code, I see that it
tries to compare X bytes in its buffer with Y bytes read from the
file, assuming that X will always be equal to Y. Is this assumption
supposed to hold for linux NFS client reads?

Thanks
Shehjar