From a8e5a2d593cbfccf530c3382c2c328d2edaa7b66 Mon Sep 17 00:00:00 2001 From: "Stewart, Sean" Date: Tue, 15 Oct 2013 15:52:54 +0000 Subject: [PATCH] [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 Acked-by: Hannes Reinecke Signed-off-by: James Bottomley --- drivers/scsi/device_handler/scsi_dh_alua.c | 26 +++++++++++++--------- 1 file 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; -- 2.30.2