On Thu, 2014-04-10 at 11:08 -0400, David Jeffery wrote: > There is an error with the medium access timeout feature of the sd driver. The > sdkp->medium_access_timed_out value is reset to zero in sd_done() in the wrong > place. Currently it is reset to zero only when a command returns sense data. > This can result in cases where the medium access check falsely triggers from > timed out commands which are hours or days apart. > > For example, an I/O command times out and is aborted. It then retries and > succeeds. But with no sense data generated and returned, the > medium_access_timed_out value is not reset. If no sd command returns sense > data, then the next command to time out (however far in time from the first > failure) will trigger the medium access timeout and put the device offline. > > The resetting of sdkp->medium_access_timed_out should occur before the check > for sense data. > > Signed-off-by: David Jeffery <djeff...@redhat.com> > > --- > > To reproduce using scsi_debug, use SCSI_DEBUG_OPT_TIMEOUT or > SCSI_DEBUG_OPT_MAC_TIMEOUT to force an I/O command to timeout. Then, remove > the opt value so the I/O will succeed on retry. Perform more I/O as desired. > Finally, repeat the process to make a new I/O command time out. Without the > patch, the device will be marked offline even though many I/O commands have > succeeded between the 2 instances of timed out commands. > > > diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c > index 470954a..a41e68e 100644 > --- a/drivers/scsi/sd.c > +++ b/drivers/scsi/sd.c > @@ -1689,12 +1689,12 @@ static int sd_done(struct scsi_cmnd *SCpnt) > sshdr.ascq)); > } > #endif > + sdkp->medium_access_timed_out = 0; > + > if (driver_byte(result) != DRIVER_SENSE && > (!sense_valid || sense_deferred)) > goto out; > > - sdkp->medium_access_timed_out = 0; > - > switch (sshdr.sense_key) { > case HARDWARE_ERROR: > case MEDIUM_ERROR: > -- > To unsubscribe from this list: send the line "unsubscribe linux-scsi" in > the body of a message to majord...@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html
Hey James- Is there some reason why this patch was never accepted? David posted it a couple of times last year and Martin ack'ed it, but I don't see it in your tree, and I don't see any other comments on it. It seems like something that ought to be fixed. Reviewed-by: Ewan D. Milne <emi...@redhat.com> -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html