From f87146bba523cad0196aa8e80ca9e8243d7a6c0c Mon Sep 17 00:00:00 2001
From: Hannes Reinecke <hare@suse.de>
Date: Mon, 29 Mar 2010 09:29:24 +0200
Subject: [SCSI] sd: quiet spurious error messages in READ_CAPACITY(16)

sd always tries to submit a READ_CAPACITY(16) CDB,
regardless whether the host actually supports it.
queuecommand() will then return DID_ABORT, which is
not qualified enough to detect the true cause here.
So better check in sd_try_rc16 first if the cdblen
is supported.

Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>
---
 drivers/scsi/sd.c | 2 ++
 1 file changed, 2 insertions(+)

(limited to 'drivers/scsi/sd.c')

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 58c62ff42ab3..7955bc226125 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -1573,6 +1573,8 @@ static int read_capacity_10(struct scsi_disk *sdkp, struct scsi_device *sdp,
 
 static int sd_try_rc16_first(struct scsi_device *sdp)
 {
+	if (sdp->host->max_cmd_len < 16)
+		return 0;
 	if (sdp->scsi_level > SCSI_SPC_2)
 		return 1;
 	if (scsi_device_protection(sdp))
-- 
cgit v1.2.3


From 3233ac19811fe17033b537832ca7b59df8bf4aa9 Mon Sep 17 00:00:00 2001
From: James Bottomley <James.Bottomley@suse.de>
Date: Thu, 1 Apr 2010 10:30:01 -0400
Subject: [SCSI] sd: retry read_capacity on UNIT_ATTENTION

Hazard testing uncovered yet another bug in sd. Under heavy reset
activity the retry counter might be exhausted and the command will be
returned with sense UNIT_ATTENTION/0x29/00 (POWER ON, RESET, OR BUS
DEVICE RESET OCCURRED). In those cases we should just increase the
retry counter again, retrying one more to clear up this Unit Attention
state.

[jejb: update to work with RC16 devices and not to loop endlessly]
Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>
---
 drivers/scsi/sd.c | 23 ++++++++++++++++++++---
 1 file changed, 20 insertions(+), 3 deletions(-)

(limited to 'drivers/scsi/sd.c')

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 7955bc226125..015a597a852e 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -1433,6 +1433,8 @@ static void read_capacity_error(struct scsi_disk *sdkp, struct scsi_device *sdp,
 #error RC16_LEN must not be more than SD_BUF_SIZE
 #endif
 
+#define READ_CAPACITY_RETRIES_ON_RESET	10
+
 static int read_capacity_16(struct scsi_disk *sdkp, struct scsi_device *sdp,
 						unsigned char *buffer)
 {
@@ -1440,7 +1442,7 @@ static int read_capacity_16(struct scsi_disk *sdkp, struct scsi_device *sdp,
 	struct scsi_sense_hdr sshdr;
 	int sense_valid = 0;
 	int the_result;
-	int retries = 3;
+	int retries = 3, reset_retries = READ_CAPACITY_RETRIES_ON_RESET;
 	unsigned int alignment;
 	unsigned long long lba;
 	unsigned sector_size;
@@ -1469,6 +1471,13 @@ static int read_capacity_16(struct scsi_disk *sdkp, struct scsi_device *sdp,
 				 * Invalid Field in CDB, just retry
 				 * silently with RC10 */
 				return -EINVAL;
+			if (sense_valid &&
+			    sshdr.sense_key == UNIT_ATTENTION &&
+			    sshdr.asc == 0x29 && sshdr.ascq == 0x00)
+				/* Device reset might occur several times,
+				 * give it one more chance */
+				if (--reset_retries > 0)
+					continue;
 		}
 		retries--;
 
@@ -1527,7 +1536,7 @@ static int read_capacity_10(struct scsi_disk *sdkp, struct scsi_device *sdp,
 	struct scsi_sense_hdr sshdr;
 	int sense_valid = 0;
 	int the_result;
-	int retries = 3;
+	int retries = 3, reset_retries = READ_CAPACITY_RETRIES_ON_RESET;
 	sector_t lba;
 	unsigned sector_size;
 
@@ -1543,8 +1552,16 @@ static int read_capacity_10(struct scsi_disk *sdkp, struct scsi_device *sdp,
 		if (media_not_present(sdkp, &sshdr))
 			return -ENODEV;
 
-		if (the_result)
+		if (the_result) {
 			sense_valid = scsi_sense_valid(&sshdr);
+			if (sense_valid &&
+			    sshdr.sense_key == UNIT_ATTENTION &&
+			    sshdr.asc == 0x29 && sshdr.ascq == 0x00)
+				/* Device reset might occur several times,
+				 * give it one more chance */
+				if (--reset_retries > 0)
+					continue;
+		}
 		retries--;
 
 	} while (the_result && retries);
-- 
cgit v1.2.3


From c213e1407be6b04b144794399a91472e0ef92aec Mon Sep 17 00:00:00 2001
From: Hannes Reinecke <hare@suse.de>
Date: Tue, 4 May 2010 16:49:21 +0200
Subject: [SCSI] Enable retries for SYNCRONIZE_CACHE commands to fix I/O error

Some arrays are giving I/O errors with ext3 filesystems when
SYNCHRONIZE_CACHE gets a UNIT_ATTENTION.  What is happening is that
these commands have no retries, so the UNIT_ATTENTION causes the
barrier to fail.  We should be enable retries here to clear any
transient error and allow the barrier to succeed.

Signed-off-by: Hannes Reinecke <hare@suse.de>
Cc: Stable Tree <stable@kernel.org>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>
---
 drivers/scsi/sd.c | 1 +
 1 file changed, 1 insertion(+)

(limited to 'drivers/scsi/sd.c')

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 8b827f37b03e..de6c60320f6f 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -1040,6 +1040,7 @@ static void sd_prepare_flush(struct request_queue *q, struct request *rq)
 {
 	rq->cmd_type = REQ_TYPE_BLOCK_PC;
 	rq->timeout = SD_TIMEOUT;
+	rq->retries = SD_MAX_RETRIES;
 	rq->cmd[0] = SYNCHRONIZE_CACHE;
 	rq->cmd_len = 10;
 }
-- 
cgit v1.2.3