AIO, SMB2 and Samba 3.6

[Andrew Bartlett]

On Wed, 2012-02-22 at 10:54 +0100, Volker Lendecke wrote:
> On Wed, Feb 22, 2012 at 03:56:52PM +1100, Andrew Bartlett wrote:
> > I've now reproduced this on the NAS with a level 10 log, using
> > smbclient4 from master:
> > 
> > bin/smbclient //192.168.1.167/media -Uuser%password
> > smb: \> put /data/kvm/cdroms/FreeBSD-8.2-RELEASE-amd64-bootonly.iso
> > freebsd7.iso
> > Error writing file: socket_error
> > 
> > It seems to me that the underlying AIO layer isn't returning promptly or
> > correctly.  It appears that after the socket error, smbclient still
> > tries to close the file, and this then triggers finally an AIO error. 
> 
> The reference to freebsd makes me wonder if the NAS box
> might be FreeBSD based. 

Sorry for the red herring.  That was just a 50MB file I had lying
around.  It is Linux 2.6.37.6.RNx86_64.2.2 and glibc 2.7-18lenny7.

> I think I've seen problems with
> Samba setting up the RT signal we choose for AIO. It should
> have disabled using aio. Can you check further up in the log
> whether that might be the case? 

This certainly matches the symptoms: what would the message be in that
case?  The log is the full log from the point of the share connection. 

> Also, you might try the
> aio_fork and aio_pthread modules.

Indeed, given the well known performance issues with glibc AIO
aio_pthread has already been recommended.  This task was just to first
sort out (if possible) why the default aio didn't work at all.

Thanks,

Andrew Bartlett

-- 
Andrew Bartlett                                http://samba.org/~abartlet/
Authentication Developer, Samba Team           http://samba.org