[Thinlinc-technical] Thinlinc 4.0 & 64bit unfsd

[Rafael Ostertag]

Hi list

We have a rather annoying issue here, involving the 64bit unfsd shipped 
with the ThinLinc client 4.0.0: when copying files to an exported volume 
on the client machine, we get 'Input/output error'. Sometimes it takes a 
while until copying files fails, other times it fails right away on the 
first file to copy.

Tracing cp(1) using strace(1) revealed, that the open(2) syscall fails, 
when the O_EXCL flag is used in combination with O_CREAT, in order to 
create the destination file initially on the client machine, leaving an 
empty file behind. In case the destination already exists, cp(1) simply 
opens it using O_WRONLY|O_TRUNC which does not fail.

So we basically end up with having to issue the copy command twice in 
order to copy a file to a volume: once in order to create the empty file 
and tricking the second attempt into passing O_WRONLY|O_TRUNC to open(2).

This behavior is not limited to cp(1), Thunar (XFCE), Caja (MATE), and 
Nautilus also complain about Input/output error when files are initially 
created on the exported volume.

We replaced the 64bit ThinLinc client by the 32bit version and the issue 
was gone. So, we strongly suspect the 64bit unfsd being the culprit.

Does anybody else experience this behavior?

Cheers
rafi

P.S.: ThinLinc server is running Ubuntu 12.04 AMD64 and clients are 
running Ubuntu 12.04/12.10 AMD64. ThinLinc 4.0.0 on both ends.


-- 
Rafael Ostertag, Technischer Assistent
Institut für Mathematik, Universität Zürich
Winterthurerstrasse 190, CH-8057 Zürich, Office: Y27-J40
Tel: ++41 (0)44 63-55866, rafael.ostertag at math.uzh.ch