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authorStewart, Sean <Sean.Stewart@netapp.com>2013-10-15 15:52:54 +0000
committerJames Bottomley <JBottomley@Parallels.com>2013-10-25 11:19:33 +0100
commita8e5a2d593cbfccf530c3382c2c328d2edaa7b66 (patch)
tree879d7cc9168fbe2c9fceba2c16923f59c2f69ed1 /drivers/scsi
parentc20ee7b56e0a1937b41919813e5a98373ca48ae8 (diff)
downloadlinux-a8e5a2d593cbfccf530c3382c2c328d2edaa7b66.tar.bz2
[SCSI] scsi_dh_alua: ALUA handler attach should succeed while TPG is transitioning
During testing, it was discovered that when a device tries to attach to the alua handler while in TPG state of transitioning, the alua_rtpg function will wait for it to exit the state before allowing it to continue. As a result, if the 60 second timeout expires, the alua handler will not attach to the device. To fix this, I have introduced an input argument to alua_rtpg called wait_for_transition. The idea is that it will wait for the transition to complete before an activation (because the current TPG state has some bearing in that case), but during a discovery if it is transitioning, it will not wait, and will store the state as standby for the time being. I believe the precedent exists for this from commit c0d289b3e59577532c45ee9110ef81bd7b341272 Since if the device reports a state of transitioning, it can transition to other more valid states, and it has been established TPGS is supported on the device, if it is attaching. Signed-off-by: Sean Stewart <Sean.Stewart@netapp.com> Acked-by: Hannes Reinecke <hare@suse.de> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
Diffstat (limited to 'drivers/scsi')
-rw-r--r--drivers/scsi/device_handler/scsi_dh_alua.c26
1 files changed, 16 insertions, 10 deletions
diff --git a/drivers/scsi/device_handler/scsi_dh_alua.c b/drivers/scsi/device_handler/scsi_dh_alua.c
index 78205cc2059c..5248c888552b 100644
--- a/drivers/scsi/device_handler/scsi_dh_alua.c
+++ b/drivers/scsi/device_handler/scsi_dh_alua.c
@@ -522,12 +522,13 @@ static int alua_check_sense(struct scsi_device *sdev,
/*
* alua_rtpg - Evaluate REPORT TARGET GROUP STATES
* @sdev: the device to be evaluated.
+ * @wait_for_transition: if nonzero, wait ALUA_FAILOVER_TIMEOUT seconds for device to exit transitioning state
*
* Evaluate the Target Port Group State.
* Returns SCSI_DH_DEV_OFFLINED if the path is
* found to be unusable.
*/
-static int alua_rtpg(struct scsi_device *sdev, struct alua_dh_data *h)
+static int alua_rtpg(struct scsi_device *sdev, struct alua_dh_data *h, int wait_for_transition)
{
struct scsi_sense_hdr sense_hdr;
int len, k, off, valid_states = 0;
@@ -599,7 +600,7 @@ static int alua_rtpg(struct scsi_device *sdev, struct alua_dh_data *h)
else
h->transition_tmo = ALUA_FAILOVER_TIMEOUT;
- if (orig_transition_tmo != h->transition_tmo) {
+ if (wait_for_transition && (orig_transition_tmo != h->transition_tmo)) {
sdev_printk(KERN_INFO, sdev,
"%s: transition timeout set to %d seconds\n",
ALUA_DH_NAME, h->transition_tmo);
@@ -637,14 +638,19 @@ static int alua_rtpg(struct scsi_device *sdev, struct alua_dh_data *h)
switch (h->state) {
case TPGS_STATE_TRANSITIONING:
- if (time_before(jiffies, expiry)) {
- /* State transition, retry */
- interval += 2000;
- msleep(interval);
- goto retry;
+ if (wait_for_transition) {
+ if (time_before(jiffies, expiry)) {
+ /* State transition, retry */
+ interval += 2000;
+ msleep(interval);
+ goto retry;
+ }
+ err = SCSI_DH_RETRY;
+ } else {
+ err = SCSI_DH_OK;
}
+
/* Transitioning time exceeded, set port to standby */
- err = SCSI_DH_RETRY;
h->state = TPGS_STATE_STANDBY;
break;
case TPGS_STATE_OFFLINE:
@@ -678,7 +684,7 @@ static int alua_initialize(struct scsi_device *sdev, struct alua_dh_data *h)
if (err != SCSI_DH_OK)
goto out;
- err = alua_rtpg(sdev, h);
+ err = alua_rtpg(sdev, h, 0);
if (err != SCSI_DH_OK)
goto out;
@@ -738,7 +744,7 @@ static int alua_activate(struct scsi_device *sdev,
int err = SCSI_DH_OK;
int stpg = 0;
- err = alua_rtpg(sdev, h);
+ err = alua_rtpg(sdev, h, 1);
if (err != SCSI_DH_OK)
goto out;