Re: [PATCH] sd: do not set changed flag on all unit attention conditions

[Paolo Bonzini <pbonzini@redhat.com>]

Il 17/07/2012 14:21, James Bottomley ha scritto:
>> Yes, I realize failing only on specific sense codes as I did it in the
>> patch is not going to work.  However, the other way round is not
>> problematic (explicitly allow some sense codes, fail on all others).
> 
> Heh, I once thought that, but there's no end to the strange ideas USB
> manufacturers get.

:)

>> > Another example is "target operating conditions have changed".  QEMU
>> > cannot report such changes because scsi_error prints a warning (fine)
>> > and then passes the unit attention upwards.  With removable drives, this
>> > has the same problem as resizing.
> Why would a removable device ever use any of the codes under this ASC
> when the medium hasn't changed?  They're all for arrays (well except
> 0x10 and 0x11 ... and they're only supposed to apply to tape changers
> with autoload support declared in the control mode page).

There are also a couple of generic ones such as "reported luns have
changed".  I also considered briefly using "inquiry data has changed" to
reload the unmap parameters after live snapshot or storage migration.  I
dropped the idea, please don't put me in the same bin as the USB
manufacturers.

Paolo