[PATCH] sd: always retry READ CAPACITY for ALUA state transition

[Hannes Reinecke <hare@suse.de>]

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@suse.de>
---
 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--;
 
-- 
1.8.5.2