scsi: handle flush errors properly

Flush commands don't transfer data and thus need to be special cased
in the I/O completion handler so that we can propagate errors to
the block layer and filesystem.

Signed-off-by: James Bottomley <JBottomley@Parallels.com>
Reported-by: Steven Haber <steven@qumulo.com>
Tested-by: Steven Haber <steven@qumulo.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Cc: stable@vger.kernel.org
Signed-off-by: Christoph Hellwig <hch@lst.de>

diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index f7e316368c99ea289deb85a66541a88f06577737..3f50dfcb3227a834069a530bd8628e1cf9ee603d 100644 (file)
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -733,6 +733,14 @@ void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes)
                        scsi_next_command(cmd);
                        return;
                }
+       } else if (blk_rq_bytes(req) == 0 && result && !sense_deferred) {
+               /*
+                * Certain non BLOCK_PC requests are commands that don't
+                * actually transfer anything (FLUSH), so cannot use
+                * good_bytes != blk_rq_bytes(req) as the signal for an error.
+                * This sets the error explicitly for the problem case.
+                */
+               error = __scsi_error_from_host_byte(cmd, result);
        }
 
        /* no bidi support for !REQ_TYPE_BLOCK_PC yet */