[3.11.y.z extended stable] Patch "scsi: handle flush errors properly" has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    scsi: handle flush errors properly

to the linux-3.11.y-queue branch of the 3.11.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.11.y-queue

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.11.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From 22959457bcceea7486bc377f15fb5336f23038f1 Mon Sep 17 00:00:00 2001
From: James Bottomley <JBottomley at Parallels.com>
Date: Thu, 3 Jul 2014 19:17:34 +0200
Subject: scsi: handle flush errors properly

commit 89fb4cd1f717a871ef79fa7debbe840e3225cd54 upstream.

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 at Parallels.com>
Reported-by: Steven Haber <steven at qumulo.com>
Tested-by: Steven Haber <steven at qumulo.com>
Reviewed-by: Martin K. Petersen <martin.petersen at oracle.com>
Signed-off-by: Christoph Hellwig <hch at lst.de>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/scsi/scsi_lib.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 124392f3091e..96e537a8604d 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -831,6 +831,14 @@ 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 */
--
1.9.1