On 4/30/2015 5:56 PM, Hannes Reinecke wrote:
On 04/28/2015 11:18 PM, James Bottomley wrote:
On Mon, 2015-04-27 at 11:35 +0200, Hannes Reinecke wrote:
During ALUA state transitions the device might return
a sense code 02/04/0a (Logical unit not accessible, asymmetric
access state transition). As this is a transient error
we should just retry the READ CAPACITY call until
the state transition finishes and the correct
capacity can be returned.
Signed-off-by: Hannes Reinecke <hare@xxxxxxx>
---
drivers/scsi/sd.c | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 79beebf..7178b05 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -1987,6 +1987,11 @@ static int read_capacity_16(struct scsi_disk *sdkp, struct scsi_device *sdp,
* give it one more chance */
if (--reset_retries > 0)
continue;
+ if (sense_valid &&
+ sshdr.sense_key == NOT_READY &&
+ sshdr.asc == 0x04 && sshdr.ascq == 0x0A)
+ /* ALUA state transition; always retry */
+ continue;
}
retries--;
@@ -2069,6 +2074,11 @@ static int read_capacity_10(struct scsi_disk *sdkp, struct scsi_device *sdp,
* give it one more chance */
if (--reset_retries > 0)
continue;
+ if (sense_valid &&
+ sshdr.sense_key == NOT_READY &&
+ sshdr.asc == 0x04 && sshdr.ascq == 0x0A)
+ /* ALUA state transition; always retry */
+ continue;
}
retries--;
Got to say I really don't like this infinite retry possibility. How
long does the ALUA transition take? Would increasing retries work (or
even hijacking reset_retries)?
Well ... transitioning could be quite long (NetApp FAS has a
transition timeout of 30 _minutes_ ...).
Well, actually NetApp FAS has a transition timeout of 2 minutes, and not
30 minutes - as reported in the IMPLICIT TRANSITION TIMEOUT value in the
extended RTPG data.
-Martin
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