isp driver - inquiry changed

[Scott Long]

Matthew Jacob wrote:

>  Switch as in 'Fabric' or 'Segmented FC-AL'?
> 
> The panic looks like the ones where as far as the system is concerned the
> disk went away.
> 
> Right now, certain fabric and loop events cause the isp driver to think the
> target has gone away, and this gets sent as async event upstream. I'm
> beginning to think that this is a losing proposition for FreeBSD- on the
> other hand, the unexpected disappearance of a device isn't handled well by
> FreeBSD *either*.

Yeah, the most serious and hard to fix problem is that most filesystems
and I/O related parts of the VM assume that all I/O succeeds.

> 
> When I did a hardening exercise at Mirapoint for the FreeBSD isp driver and
> SCSI midlayer, I seem to recall that I put in a deferred device
> disappearance algorithm. Maybe I should check with Mirapoint to see if I can
> pull that code back.
> 

John Polstra committed some fixes about a month ago related to device 
disappearance in SCSI.  Might be good to look at that too.

Scott