From a9b589d90e3d7748dae459031c2d912cd9e83c88 Mon Sep 17 00:00:00 2001
From: Vladislav Bolkhovitin <vst@vlnb.net>
Date: Thu, 6 Nov 2008 13:57:52 +0300
Subject: [PATCH] [SCSI] scsi_error: TASK ABORTED status handling improvement

This patch improves handling of TASK ABORTED status by Linux SCSI
mid-layer. Currently, command returned with this status considered
failed and returned to upper layers. It leads to additional error
recovery load on file systems and block layer, which sometimes can
cause undesired side effects, like I/O errors and file systems
corruptions. See http://lkml.org/lkml/2008/11/1/38, for instance.

From other side, TASK ABORTED status is returned by SCSI target if the
corresponding command was aborted by another initiator and the target
has TAS bit set in the control mode page. So, in the majority of cases
commands with TASK ABORTED status should be simply retried. In other
cases, maybe_retry path will not retry if no retries are allowed.

This patch implement suggestion by James Bottomley from
http://marc.info/?l=linux-scsi&m=121932916906009&w=2.

Signed-off-by: Vladislav Bolkhovitin <vst@vlnb.net>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
---
 drivers/scsi/scsi_error.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c
index f5767dc48d61a5..381838ebd4604e 100644
--- a/drivers/scsi/scsi_error.c
+++ b/drivers/scsi/scsi_error.c
@@ -1406,8 +1406,9 @@ int scsi_decide_disposition(struct scsi_cmnd *scmd)
 		return ADD_TO_MLQUEUE;
 	case GOOD:
 	case COMMAND_TERMINATED:
-	case TASK_ABORTED:
 		return SUCCESS;
+	case TASK_ABORTED:
+		goto maybe_retry;
 	case CHECK_CONDITION:
 		rtn = scsi_check_sense(scmd);
 		if (rtn == NEEDS_RETRY)
-- 
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