Data corruption with pktcdvd, kernel 2.6.10

	Hi;

	I have played with the pktcdvd patch in the past, and most
recently with the implementation in the 2.6.10 kernel, but never
really stressed it. However, someone recently complained to me that
it quite often resulted in corrupted files for them, so I performed
a stress test; copy a kernel source tree to a cdrw and a dvd+rw.
(mount /dev/pktcdvd/cdrw /cdrw -o rw,noatime)
(cp -a /foo/2.6.10 /cdrw)
	Well, diff -r shows many corrupt files in both cases.
The corruption is either that the file is completely zero, or at
some point it ends in zero data. In other words, all or part of
the file end up as zero's.
	Simpler tests, like copying a flat dir filled with 50meg
of images did not turn up corruption.
	I would have liked to compare writing to dvd+rw without
pktcdvd, but although I could make a udf fs on the disc, mount it and
start writing to it, the throughput was impossibly slow. (like 1meg in
several minutes-- at best.) Using pktcdvd was much faster, but it
seems to bog down after a while into the kernel tree copy-- and if you
look at the drive light, it seems to be doing lots of reading and 
then little blips of writing. 'vmstat 1' shows very little bi/bo,
often times 0/0.
	Can anyone suggest what might be done to find out what is
going wrong here? I am using vanilla 2.6.10, udftools-1.0.0b-r3,
a liteon LDW-451S dvd writer. The kernel is SMP with preempt enabled.
The writer and the hardisc are both ATA.
	Let me know if I can help with more information or testing.

Thanks;

Paul
[email protected]