Re: [Nbd] nbd-server segfault on x86_64

["JaniD++" <djani22@...60...>]

----- Original Message ----- 
From: "Wouter Verhelst" <wouter@...3...>
To: "JaniD++" <djani22@...60...>
Cc: <nbd-general@lists.sourceforge.net>
Sent: Monday, February 13, 2006 11:53 PM
Subject: Re: [Nbd] nbd-server segfault on x86_64


> On Mon, Feb 13, 2006 at 10:53:32PM +0100, JaniD++ wrote:
> [...]
> > > > The system:
> > > > P4 Cual core(64 bit), Fedora Core 4 X86_64, Kernel 2.6.16-rc1-git4,
nbd
> > > > 2.8.2, compiled on this system.
> > >
> > > I believe these problems have been fixed in 2.8.3, though I'm not
> > > entirely sure.  Could you try with 2.8.3? If that does not work, we'll
> > > need to debug a bit more.
> >
> > Not needed.
> > It looks like fixed on 2.8.3.
>
> Right, I thought as much.
>
> > > > And another one issue:
> > > >
> > > > My client machine is i386 system, and i get this, when i try to
> > > > connect to 3.3TB blockdev: "Exported device is too big for me. Get
> > > > 64-bit machine :-("
> > > >
> > > > This is really need 64 bit machine?
> > > > This problem is cannot be solve with bit-shifting?
> > >
> > > Maybe, but that would require changes to the kernel driver.
> > >
> > > > This needs the >4GB memory access?
> > >
> > > No, it needs a useful unsigned long data type to be able to store
> > > offsets.
> > >
> > > I'm not 100% sure this check is still required, though. I'll try to
find
> > > out.
> >
> > Can i help to try / test?
>
> No, I can test it using sparse files. No need :-)

OK, anyway i want to be _really_ sure, before i feed in the big xfs, and try
xfs_grow.

>
> > (I have 4 nodes, all 3.3TB, but the NBD looks only 4x 2.0TB, and inside
one
> > 8TB XFS, with valuable data.
> > But the blockdevice is free from 8TB to 13.2TB.)
> >
> > only note:
> > The NBD write-deadlock problem is finally fixed in kernel 2.6.16!
>
> Whee!
>
> > (thanks, to Herbert Xu, and me :-)
>
> That's _really_ cool. Can you point me to the details of that one? I'd
> be interested in finding out what the heck was wrong; I could then
> perhaps get a workaround in nbd-server for older kernels as well.

If i think right, there is no way to workaround for older kernels. :(

Watch this:
http://kernel.org/pub/linux/kernel/v2.6/testing/ChangeLog-2.6.16-rc1

And this patch:
[PATCH] nbd: fix TX/RX race condition

This was tricky. ;-)

Anyway, i think i found more bugs, but smaller, and first i will try the new
server, and come back later...

Cheers,
Janos

>
> -- 
> Fun will now commence
>   -- Seven Of Nine, "Ashes to Ashes", stardate 53679.4
>
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