Process hangs on blk_congestion_wait copying large file to cifs filesystem

[Nuno Ferreira <nuno.ferreira@graycell.biz>]

Hi,
I'm trying to copy a large file (200Mb or bigger) from an ext3
filesystem to a windows share mounted using CIFS and the cp process
hangs, sometimes for a long time (several minutes).
Calling ps, I can see that it's blocking on blk_congestion_wait.

Trying to edit a file on the same ext3 filesystem using vi blocks on the
same function. However, during that that same time that vi and cp were
blocked, I was able to do a "find /usr/share/doc" and it completed
normally, in a few seconds.

Eventually the copy succeeds but it takes a long time (20 minutes to
copy 200Mb) and the computer is unusable during most of that time.

This is copying from my laptop (IDE disk), the network card is a RTL8139
using 8139cp drivers.

Is someone seeing a similiar problem? What extra info is needed to debug
it?

Thanks
-- 
Nuno Ferreira