[dm-devel] [REGRESSION][BISECTED] virtio-blk serial attribute causes guest to hang [Was: Re: [PATCH UPDATED 4/5] dm: implement REQ_FLUSH/FUA support for request-based dm]

[Ryan Harper]

* Mike Snitzer <snitzer at redhat.com> [2010-09-09 12:56]:
> On Thu, Sep 09 2010 at 12:03pm -0400,
> Ryan Harper <ryanh at us.ibm.com> wrote:
> 
> > * Mike Snitzer <snitzer at redhat.com> [2010-09-09 10:58]:
> 
> > > I'm using virtio-blk w/ cache=none for the root device.  virtio-blk
> > > isn't used for any other devices in the guest.
> > 
> > And you don't have any other disks in the guest (I see just the root and
> > the cdrom), the lv stuff is happening against some sort of dummy target?
> 
> Correct.  I have used variants of the script I provided against both
> scsi-debug devices and iscsi devices in the guest.  The script I shared
> uses multipath on scsi-debug (ram-based) devices.
> 
> That script causes udev to run its various callouts via multipath and
> LVM (both packages, upstream and RHEL6, now use udev).
> 
> I have verified that I no longer get the hang if I switch the root
> device from virtio to ide.

And in the failing case, do you see:

/sys/block/vda/serial 

attribute in sysfs?


-- 
Ryan Harper
Software Engineer; Linux Technology Center
IBM Corp., Austin, Tx
ryanh at us.ibm.com