Hi Babu, Thanks for finding this. On Tue, Jan 24 2012 at 3:38pm -0500, Moger, Babu <Babu.Moger@xxxxxxxxxx> wrote: > Resubmitting as my previous post had format issues and did not go linux-scsi. > > This patch fixes the host byte settings DID_TARGET_FAILURE and DID_NEXUS_FAILURE. > The function __scsi_error_from_host_byte, tries to reset the host byte to DID_OK. But that > does not happen because of the OR operation. > > Here is the flow. > scsi_softirq_done-> scsi_decide_disposition -> __scsi_error_from_host_byte or more accurately: scsi_softirq_done -> scsi_decide_disposition scsi_softirq_done -> scsi_finish_command -> scsi_io_completion -> __scsi_error_from_host_byte > Let's take an example with DID_NEXUS_FAILURE. In scsi_decide_disposition, result will be set as > DID_NEXUS_FAILURE (=0x11). Then in __scsi_error_from_host_byte, when we do OR with > DID_OK. Purpose is to reset it back to DID_OK. But that does not happen. This patch fixes this issue. We clearly aren't properly resetting to DID_OK but I'm not seeing an obvious "nasty bug" that is lurking due to this. Am I missing something? __scsi_error_from_host_byte() is setting error which is passed back up via blk_end_request() and blk_end_request_all(). And in my previous testing I know that corresponding errors are making it out to dm-multipath (e.g. -EREMOTEIO). Also, your patch header is missing the location where DID_OK is not properly matched (because it wasn't set exclussively due to being or'd). Looks like scsi_noretry_cmd() will be made more efficient because it will match DID_OK immediately. Any other locations? Would be good to call them out. Mike -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
