Christoph Hellwig <h...@lst.de> writes: > On Fri, Jun 25, 2010 at 06:53:28PM +0200, Markus Armbruster wrote: >> For instance, -device scsi-disk,drive=foo -device scsi-disk,drive=foo >> happily creates two SCSI disks connected to the same block device. >> It's all downhill from there. > > And from some quick testing a while ago the thing seems to actually > work. Not that I think that it is a good idea, but do we want to change > behaviour in that respect?
Valid question. I'd answer yes. It's an easy error to make, and likely to end in massive file system corruption in the guest. >> Device usb-storage deliberately attaches twice to the same blockdev, >> which fails with the fix in place. Detach before the second attach >> there. > > Can anyone explain what the hell usb storage is actually trying to do > with the two drives? It's actually a SCSI controller with a single drive on its single bus. -device usb-storage,drive=foo creates *two* devices: usb-storage itself, which serves as SCSI controller, and scsi-disk for the drive. usb-storage copies its drive property to scsi-disk. I don't like this. Each -device should create just one device.
