[SCSI] sd: Fix handling of NO_SENSE check condition
Jamie Wellnitz [Fri, 12 Sep 2008 01:39:36 +0000 (21:39 -0400)]
The current handling of NO_SENSE check condition is the same as
RECOVERED_ERROR, and assumes that in both cases, the I/O was fully
transferred.

We have seen cases of arrays returning with NO_SENSE (no error), but
the I/O was not completely transferred, thus residual set.  Thus,
rather than return good_bytes as the entire transfer, set good_bytes
to 0, so that the midlayer then applies the residual in calculating
the transfer, and for sd, will fail the I/O and fall into a retry
path.

Signed-off-by: Jamie Wellnitz <Jamie.Wellnitz@emulex.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

drivers/scsi/sd.c

index 7c4d2e6..55e6ed4 100644 (file)
@@ -1054,7 +1054,6 @@ static int sd_done(struct scsi_cmnd *SCpnt)
                good_bytes = sd_completed_bytes(SCpnt);
                break;
        case RECOVERED_ERROR:
-       case NO_SENSE:
                /* Inform the user, but make sure that it's not treated
                 * as a hard error.
                 */
@@ -1063,6 +1062,15 @@ static int sd_done(struct scsi_cmnd *SCpnt)
                memset(SCpnt->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE);
                good_bytes = scsi_bufflen(SCpnt);
                break;
+       case NO_SENSE:
+               /* This indicates a false check condition, so ignore it.  An
+                * unknown amount of data was transferred so treat it as an
+                * error.
+                */
+               scsi_print_sense("sd", SCpnt);
+               SCpnt->result = 0;
+               memset(SCpnt->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE);
+               break;
        case ABORTED_COMMAND:
                if (sshdr.asc == 0x10) { /* DIF: Disk detected corruption */
                        scsi_print_result(SCpnt);