Am Mittwoch, 4. Januar 2012, 21:16:09 schrieb Alan Stern:
> On Tue, 3 Jan 2012, Perry Wagle wrote:
>
> > > You can test this by applying the patch below. If it fixes the
> > > problem, we'll know the diagnosis is correct.
> >
> > With the patch, I'm able to mount both disks. Thanks!
> >
> > Now what?
>
> Now that we know what the problem is, here's a real fix. Replace the
> previous patch with this one; if it works okay then I'll submit it for
> inclusion in the next stable kernel release.
Looking at the following code from scsi.c:
int scsi_dispatch_cmd(struct scsi_cmnd *cmd)
{
struct Scsi_Host *host = cmd->device->host;
unsigned long timeout;
int rtn = 0;
atomic_inc(&cmd->device->iorequest_cnt);
/* check if the device is still usable */
if (unlikely(cmd->device->sdev_state == SDEV_DEL)) {
/* in SDEV_DEL we error all commands. DID_NO_CONNECT
* returns an immediate error upwards, and signals
* that the device is no longer present */
cmd->result = DID_NO_CONNECT << 16;
scsi_done(cmd);
/* return 0 (because the command has been processed) */
goto out;
}
/* Check to see if the scsi lld made this device blocked. */
if (unlikely(scsi_device_blocked(cmd->device))) {
/*
* in blocked state, the command is just put back on
* the device queue. The suspend state has already
* blocked the queue so future requests should not
* occur until the device transitions out of the
* suspend state.
*/
scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY);
SCSI_LOG_MLQUEUE(3, printk("queuecommand : device blocked \n"));
/*
* NOTE: rtn is still zero here because we don't need the
* queue to be plugged on return (it's already stopped)
*/
goto out;
}
/*
* If SCSI-2 or lower, store the LUN value in cmnd.
*/
if (cmd->device->scsi_level <= SCSI_2 &&
cmd->device->scsi_level != SCSI_UNKNOWN) {
cmd->cmnd[1] = (cmd->cmnd[1] & 0x1f) |
(cmd->device->lun << 5 & 0xe0);
I am really unsure whether this change is really safe.
In particular I doubt it is material for the stable tree.
Regards
Oliver
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