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Commit 69723d17 authored by Hannes Reinecke's avatar Hannes Reinecke Committed by James Bottomley
Browse files

[SCSI] scsi_dh_alua: Handle all states correctly 



For ALUA we should be handling all states, independent of whether
the mode is explicit or implicit. For 'Transitioning' we should retry
for a certain amount of time; after that we're setting the port
to 'Standby' and return SCSI_DH_RETRY to signal upper layers
a retry is in order here.

Signed-off-by: default avatarHannes Reinecke <hare@suse.de>
Acked-by: default avatarMike Snitzer <snitzer@redhat.com>
Signed-off-by: default avatarJames Bottomley <James.Bottomley@suse.de>
parent e27d6169

drivers/scsi/device_handler/scsi_dh_alua.c

+38 −27
Original line number Diff line number Diff line 
/*

 * Generic SCSI-3 ALUA SCSI Device Handler

 *

 * Copyright (C) 2007, 2008 Hannes Reinecke, SUSE Linux Products GmbH.

 * Copyright (C) 2007-2010 Hannes Reinecke, SUSE Linux Products GmbH.

 * All rights reserved.

 *

 * This program is free software; you can redistribute it and/or modify
@@ -20,17 +20,19 @@ 
 *

 */

#include <linux/slab.h>

#include <linux/delay.h>

#include <scsi/scsi.h>

#include <scsi/scsi_eh.h>

#include <scsi/scsi_dh.h>



#define ALUA_DH_NAME "alua"

#define ALUA_DH_VER "1.2"

#define ALUA_DH_VER "1.3"



#define TPGS_STATE_OPTIMIZED		0x0

#define TPGS_STATE_NONOPTIMIZED		0x1

#define TPGS_STATE_STANDBY		0x2

#define TPGS_STATE_UNAVAILABLE		0x3

#define TPGS_STATE_LBA_DEPENDENT	0x4

#define TPGS_STATE_OFFLINE		0xe

#define TPGS_STATE_TRANSITIONING	0xf
@@ -39,6 +41,7 @@ 
#define TPGS_SUPPORT_NONOPTIMIZED	0x02

#define TPGS_SUPPORT_STANDBY		0x04

#define TPGS_SUPPORT_UNAVAILABLE	0x08

#define TPGS_SUPPORT_LBA_DEPENDENT	0x10

#define TPGS_SUPPORT_OFFLINE		0x40

#define TPGS_SUPPORT_TRANSITION		0x80
@@ -460,6 +463,8 @@ static char print_alua_state(int state) 
		return 'S';

	case TPGS_STATE_UNAVAILABLE:

		return 'U';

	case TPGS_STATE_LBA_DEPENDENT:

		return 'L';

	case TPGS_STATE_OFFLINE:

		return 'O';

	case TPGS_STATE_TRANSITIONING:
@@ -542,7 +547,9 @@ static int alua_rtpg(struct scsi_device *sdev, struct alua_dh_data *h) 
	int len, k, off, valid_states = 0;

	char *ucp;

	unsigned err;

	unsigned long expiry, interval = 10;



	expiry = round_jiffies_up(jiffies + ALUA_FAILOVER_TIMEOUT);

 retry:

	err = submit_rtpg(sdev, h);
@@ -553,7 +560,7 @@ static int alua_rtpg(struct scsi_device *sdev, struct alua_dh_data *h) 
			return SCSI_DH_IO;



		err = alua_check_sense(sdev, &sense_hdr);

		if (err == ADD_TO_MLQUEUE)

		if (err == ADD_TO_MLQUEUE && time_before(jiffies, expiry))

			goto retry;

		sdev_printk(KERN_INFO, sdev,

			    "%s: rtpg sense code %02x/%02x/%02x\n",
@@ -587,38 +594,37 @@ static int alua_rtpg(struct scsi_device *sdev, struct alua_dh_data *h) 
	}



	sdev_printk(KERN_INFO, sdev,

		    "%s: port group %02x state %c supports %c%c%c%c%c%c\n",

		    "%s: port group %02x state %c supports %c%c%c%c%c%c%c\n",

		    ALUA_DH_NAME, h->group_id, print_alua_state(h->state),

		    valid_states&TPGS_SUPPORT_TRANSITION?'T':'t',

		    valid_states&TPGS_SUPPORT_OFFLINE?'O':'o',

		    valid_states&TPGS_SUPPORT_LBA_DEPENDENT?'L':'l',

		    valid_states&TPGS_SUPPORT_UNAVAILABLE?'U':'u',

		    valid_states&TPGS_SUPPORT_STANDBY?'S':'s',

		    valid_states&TPGS_SUPPORT_NONOPTIMIZED?'N':'n',

		    valid_states&TPGS_SUPPORT_OPTIMIZED?'A':'a');



	if (h->tpgs & TPGS_MODE_EXPLICIT) {

	switch (h->state) {

	case TPGS_STATE_TRANSITIONING:

		if (time_before(jiffies, expiry)) {

			/* State transition, retry */

			interval *= 10;

			msleep(interval);

			goto retry;

		}

		/* Transitioning time exceeded, set port to standby */

		err = SCSI_DH_RETRY;

		h->state = TPGS_STATE_STANDBY;

		break;

	case TPGS_STATE_OFFLINE:

			/* Path is offline, fail */

	case TPGS_STATE_UNAVAILABLE:

		/* Path unuseable for unavailable/offline */

		err = SCSI_DH_DEV_OFFLINED;

		break;

	default:

			break;

		}

	} else {

		/* Only Implicit ALUA support */

		if (h->state == TPGS_STATE_OPTIMIZED ||

		    h->state == TPGS_STATE_NONOPTIMIZED ||

		    h->state == TPGS_STATE_STANDBY)

		/* Useable path if active */

		err = SCSI_DH_OK;

		else

			/* Path unuseable for unavailable/offline */

			err = SCSI_DH_DEV_OFFLINED;

		break;

	}

	return err;

}
@@ -672,7 +678,9 @@ static int alua_activate(struct scsi_device *sdev, 
			goto out;

	}



	if (h->tpgs & TPGS_MODE_EXPLICIT && h->state != TPGS_STATE_OPTIMIZED) {

	if (h->tpgs & TPGS_MODE_EXPLICIT &&

	    h->state != TPGS_STATE_OPTIMIZED &&

	    h->state != TPGS_STATE_LBA_DEPENDENT) {

		h->callback_fn = fn;

		h->callback_data = data;

		err = submit_stpg(h);
@@ -698,8 +706,11 @@ static int alua_prep_fn(struct scsi_device *sdev, struct request *req) 
	struct alua_dh_data *h = get_alua_data(sdev);

	int ret = BLKPREP_OK;



	if (h->state != TPGS_STATE_OPTIMIZED &&

	    h->state != TPGS_STATE_NONOPTIMIZED) {

	if (h->state == TPGS_STATE_TRANSITIONING)

		ret = BLKPREP_DEFER;

	else if (h->state != TPGS_STATE_OPTIMIZED &&

		 h->state != TPGS_STATE_NONOPTIMIZED &&

		 h->state != TPGS_STATE_LBA_DEPENDENT) {

		ret = BLKPREP_KILL;

		req->cmd_flags |= REQ_QUIET;

	}