[SCSI] target: Add LIO target core v4.0.0-rc6

LIO target is a full featured in-kernel target framework with the
following feature set:

High-performance, non-blocking, multithreaded architecture with SIMD
support.

Advanced SCSI feature set:

    * Persistent Reservations (PRs)
    * Asymmetric Logical Unit Assignment (ALUA)
    * Protocol and intra-nexus multiplexing, load-balancing and failover (MC/S)
    * Full Error Recovery (ERL=0,1,2)
    * Active/active task migration and session continuation (ERL=2)
    * Thin LUN provisioning (UNMAP and WRITE_SAMExx)

Multiprotocol target plugins

Storage media independence:

    * Virtualization of all storage media; transparent mapping of IO to LUNs
    * No hard limits on number of LUNs per Target; maximum LUN size ~750 TB
    * Backstores: SATA, SAS, SCSI, BluRay, DVD, FLASH, USB, ramdisk, etc.

Standards compliance:

    * Full compliance with IETF (RFC 3720)
    * Full implementation of SPC-4 PRs and ALUA

Significant code cleanups done by Christoph Hellwig.

[jejb: fix up for new block bdev exclusive interface. Minor fixes from
 Randy Dunlap and Dan Carpenter.]
Signed-off-by: Nicholas A. Bellinger <nab@linux-iscsi.org>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>

32 files changed, 27422 insertions, 0 deletions

diff --git a/drivers/Kconfig b/drivers/Kconfig
index dd0a5b5e9bf3..9bfb71ff3a6a 100644
--- a/drivers/Kconfig
+++ b/drivers/Kconfig
@@ -26,6 +26,8 @@ source "drivers/ata/Kconfig"
 
 source "drivers/md/Kconfig"
 
+source "drivers/target/Kconfig"
+
 source "drivers/message/fusion/Kconfig"
 
 source "drivers/firewire/Kconfig"
diff --git a/drivers/Makefile b/drivers/Makefile
index ef5132469f58..7eb35f479461 100644
--- a/drivers/Makefile
+++ b/drivers/Makefile
@@ -46,6 +46,7 @@ obj-y				+= macintosh/
 obj-$(CONFIG_IDE)		+= ide/
 obj-$(CONFIG_SCSI)		+= scsi/
 obj-$(CONFIG_ATA)		+= ata/
+obj-$(CONFIG_TARGET_CORE)	+= target/
 obj-$(CONFIG_MTD)		+= mtd/
 obj-$(CONFIG_SPI)		+= spi/
 obj-y				+= net/
diff --git a/drivers/target/Kconfig b/drivers/target/Kconfig
new file mode 100644
index 000000000000..2fac3be209ac
--- /dev/null
+++ b/drivers/target/Kconfig
@@ -0,0 +1,32 @@
+
+menuconfig TARGET_CORE
+	tristate "Generic Target Core Mod (TCM) and ConfigFS Infrastructure"
+	depends on SCSI && BLOCK
+	select CONFIGFS_FS
+	default n
+	help
+	Say Y or M here to enable the TCM Storage Engine and ConfigFS enabled
+	control path for target_core_mod.  This includes built-in TCM RAMDISK
+	subsystem logic for virtual LUN 0 access
+
+if TARGET_CORE
+
+config TCM_IBLOCK
+	tristate "TCM/IBLOCK Subsystem Plugin for Linux/BLOCK"
+	help
+	Say Y here to enable the TCM/IBLOCK subsystem plugin for non-buffered
+	access to Linux/Block devices using BIO
+
+config TCM_FILEIO
+	tristate "TCM/FILEIO Subsystem Plugin for Linux/VFS"
+	help
+	Say Y here to enable the TCM/FILEIO subsystem plugin for buffered
+	access to Linux/VFS struct file or struct block_device
+
+config TCM_PSCSI
+	tristate "TCM/pSCSI Subsystem Plugin for Linux/SCSI"
+	help
+	Say Y here to enable the TCM/pSCSI subsystem plugin for non-buffered
+	passthrough access to Linux/SCSI device
+
+endif
diff --git a/drivers/target/Makefile b/drivers/target/Makefile
new file mode 100644
index 000000000000..5cfd70819f08
--- /dev/null
+++ b/drivers/target/Makefile
@@ -0,0 +1,24 @@
+EXTRA_CFLAGS += -I$(srctree)/drivers/target/ -I$(srctree)/drivers/scsi/
+
+target_core_mod-y		:= target_core_configfs.o \
+				   target_core_device.o \
+				   target_core_fabric_configfs.o \
+				   target_core_fabric_lib.o \
+				   target_core_hba.o \
+				   target_core_pr.o \
+				   target_core_alua.o \
+				   target_core_scdb.o \
+				   target_core_tmr.o \
+				   target_core_tpg.o \
+				   target_core_transport.o \
+				   target_core_cdb.o \
+				   target_core_ua.o \
+				   target_core_rd.o \
+				   target_core_mib.o
+
+obj-$(CONFIG_TARGET_CORE)	+= target_core_mod.o
+
+# Subsystem modules
+obj-$(CONFIG_TCM_IBLOCK)	+= target_core_iblock.o
+obj-$(CONFIG_TCM_FILEIO)	+= target_core_file.o
+obj-$(CONFIG_TCM_PSCSI)		+= target_core_pscsi.o
diff --git a/drivers/target/target_core_alua.c b/drivers/target/target_core_alua.c
new file mode 100644
index 000000000000..2c5fcfed5934
--- /dev/null
+++ b/drivers/target/target_core_alua.c
@@ -0,0 +1,1991 @@
+/*******************************************************************************
+ * Filename:  target_core_alua.c
+ *
+ * This file contains SPC-3 compliant asymmetric logical unit assigntment (ALUA)
+ *
+ * Copyright (c) 2009-2010 Rising Tide Systems
+ * Copyright (c) 2009-2010 Linux-iSCSI.org
+ *
+ * Nicholas A. Bellinger <nab@kernel.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ *
+ ******************************************************************************/
+
+#include <linux/version.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/configfs.h>
+#include <scsi/scsi.h>
+#include <scsi/scsi_cmnd.h>
+
+#include <target/target_core_base.h>
+#include <target/target_core_device.h>
+#include <target/target_core_transport.h>
+#include <target/target_core_fabric_ops.h>
+#include <target/target_core_configfs.h>
+
+#include "target_core_alua.h"
+#include "target_core_hba.h"
+#include "target_core_ua.h"
+
+static int core_alua_check_transition(int state, int *primary);
+static int core_alua_set_tg_pt_secondary_state(
+		struct t10_alua_tg_pt_gp_member *tg_pt_gp_mem,
+		struct se_port *port, int explict, int offline);
+
+/*
+ * REPORT_TARGET_PORT_GROUPS
+ *
+ * See spc4r17 section 6.27
+ */
+int core_emulate_report_target_port_groups(struct se_cmd *cmd)
+{
+	struct se_subsystem_dev *su_dev = SE_DEV(cmd)->se_sub_dev;
+	struct se_port *port;
+	struct t10_alua_tg_pt_gp *tg_pt_gp;
+	struct t10_alua_tg_pt_gp_member *tg_pt_gp_mem;
+	unsigned char *buf = (unsigned char *)T_TASK(cmd)->t_task_buf;
+	u32 rd_len = 0, off = 4; /* Skip over RESERVED area to first
+				    Target port group descriptor */
+
+	spin_lock(&T10_ALUA(su_dev)->tg_pt_gps_lock);
+	list_for_each_entry(tg_pt_gp, &T10_ALUA(su_dev)->tg_pt_gps_list,
+			tg_pt_gp_list) {
+		/*
+		 * PREF: Preferred target port bit, determine if this
+		 * bit should be set for port group.
+		 */
+		if (tg_pt_gp->tg_pt_gp_pref)
+			buf[off] = 0x80;
+		/*
+		 * Set the ASYMMETRIC ACCESS State
+		 */
+		buf[off++] |= (atomic_read(
+			&tg_pt_gp->tg_pt_gp_alua_access_state) & 0xff);
+		/*
+		 * Set supported ASYMMETRIC ACCESS State bits
+		 */
+		buf[off] = 0x80; /* T_SUP */
+		buf[off] |= 0x40; /* O_SUP */
+		buf[off] |= 0x8; /* U_SUP */
+		buf[off] |= 0x4; /* S_SUP */
+		buf[off] |= 0x2; /* AN_SUP */
+		buf[off++] |= 0x1; /* AO_SUP */
+		/*
+		 * TARGET PORT GROUP
+		 */
+		buf[off++] = ((tg_pt_gp->tg_pt_gp_id >> 8) & 0xff);
+		buf[off++] = (tg_pt_gp->tg_pt_gp_id & 0xff);
+
+		off++; /* Skip over Reserved */
+		/*
+		 * STATUS CODE
+		 */
+		buf[off++] = (tg_pt_gp->tg_pt_gp_alua_access_status & 0xff);
+		/*
+		 * Vendor Specific field
+		 */
+		buf[off++] = 0x00;
+		/*
+		 * TARGET PORT COUNT
+		 */
+		buf[off++] = (tg_pt_gp->tg_pt_gp_members & 0xff);
+		rd_len += 8;
+
+		spin_lock(&tg_pt_gp->tg_pt_gp_lock);
+		list_for_each_entry(tg_pt_gp_mem, &tg_pt_gp->tg_pt_gp_mem_list,
+				tg_pt_gp_mem_list) {
+			port = tg_pt_gp_mem->tg_pt;
+			/*
+			 * Start Target Port descriptor format
+			 *
+			 * See spc4r17 section 6.2.7 Table 247
+			 */
+			off += 2; /* Skip over Obsolete */
+			/*
+			 * Set RELATIVE TARGET PORT IDENTIFIER
+			 */
+			buf[off++] = ((port->sep_rtpi >> 8) & 0xff);
+			buf[off++] = (port->sep_rtpi & 0xff);
+			rd_len += 4;
+		}
+		spin_unlock(&tg_pt_gp->tg_pt_gp_lock);
+	}
+	spin_unlock(&T10_ALUA(su_dev)->tg_pt_gps_lock);
+	/*
+	 * Set the RETURN DATA LENGTH set in the header of the DataIN Payload
+	 */
+	buf[0] = ((rd_len >> 24) & 0xff);
+	buf[1] = ((rd_len >> 16) & 0xff);
+	buf[2] = ((rd_len >> 8) & 0xff);
+	buf[3] = (rd_len & 0xff);
+
+	return 0;
+}
+
+/*
+ * SET_TARGET_PORT_GROUPS for explict ALUA operation.
+ *
+ * See spc4r17 section 6.35
+ */
+int core_emulate_set_target_port_groups(struct se_cmd *cmd)
+{
+	struct se_device *dev = SE_DEV(cmd);
+	struct se_subsystem_dev *su_dev = SE_DEV(cmd)->se_sub_dev;
+	struct se_port *port, *l_port = SE_LUN(cmd)->lun_sep;
+	struct se_node_acl *nacl = SE_SESS(cmd)->se_node_acl;
+	struct t10_alua_tg_pt_gp *tg_pt_gp = NULL, *l_tg_pt_gp;
+	struct t10_alua_tg_pt_gp_member *tg_pt_gp_mem, *l_tg_pt_gp_mem;
+	unsigned char *buf = (unsigned char *)T_TASK(cmd)->t_task_buf;
+	unsigned char *ptr = &buf[4]; /* Skip over RESERVED area in header */
+	u32 len = 4; /* Skip over RESERVED area in header */
+	int alua_access_state, primary = 0, rc;
+	u16 tg_pt_id, rtpi;
+
+	if (!(l_port))
+		return PYX_TRANSPORT_LU_COMM_FAILURE;
+	/*
+	 * Determine if explict ALUA via SET_TARGET_PORT_GROUPS is allowed
+	 * for the local tg_pt_gp.
+	 */
+	l_tg_pt_gp_mem = l_port->sep_alua_tg_pt_gp_mem;
+	if (!(l_tg_pt_gp_mem)) {
+		printk(KERN_ERR "Unable to access l_port->sep_alua_tg_pt_gp_mem\n");
+		return PYX_TRANSPORT_UNKNOWN_SAM_OPCODE;
+	}
+	spin_lock(&l_tg_pt_gp_mem->tg_pt_gp_mem_lock);
+	l_tg_pt_gp = l_tg_pt_gp_mem->tg_pt_gp;
+	if (!(l_tg_pt_gp)) {
+		spin_unlock(&l_tg_pt_gp_mem->tg_pt_gp_mem_lock);
+		printk(KERN_ERR "Unable to access *l_tg_pt_gp_mem->tg_pt_gp\n");
+		return PYX_TRANSPORT_UNKNOWN_SAM_OPCODE;
+	}
+	rc = (l_tg_pt_gp->tg_pt_gp_alua_access_type & TPGS_EXPLICT_ALUA);
+	spin_unlock(&l_tg_pt_gp_mem->tg_pt_gp_mem_lock);
+
+	if (!(rc)) {
+		printk(KERN_INFO "Unable to process SET_TARGET_PORT_GROUPS"
+				" while TPGS_EXPLICT_ALUA is disabled\n");
+		return PYX_TRANSPORT_UNKNOWN_SAM_OPCODE;
+	}
+
+	while (len < cmd->data_length) {
+		alua_access_state = (ptr[0] & 0x0f);
+		/*
+		 * Check the received ALUA access state, and determine if
+		 * the state is a primary or secondary target port asymmetric
+		 * access state.
+		 */
+		rc = core_alua_check_transition(alua_access_state, &primary);
+		if (rc != 0) {
+			/*
+			 * If the SET TARGET PORT GROUPS attempts to establish
+			 * an invalid combination of target port asymmetric
+			 * access states or attempts to establish an
+			 * unsupported target port asymmetric access state,
+			 * then the command shall be terminated with CHECK
+			 * CONDITION status, with the sense key set to ILLEGAL
+			 * REQUEST, and the additional sense code set to INVALID
+			 * FIELD IN PARAMETER LIST.
+			 */
+			return PYX_TRANSPORT_INVALID_PARAMETER_LIST;
+		}
+		rc = -1;
+		/*
+		 * If the ASYMMETRIC ACCESS STATE field (see table 267)
+		 * specifies a primary target port asymmetric access state,
+		 * then the TARGET PORT GROUP OR TARGET PORT field specifies
+		 * a primary target port group for which the primary target
+		 * port asymmetric access state shall be changed. If the
+		 * ASYMMETRIC ACCESS STATE field specifies a secondary target
+		 * port asymmetric access state, then the TARGET PORT GROUP OR
+		 * TARGET PORT field specifies the relative target port
+		 * identifier (see 3.1.120) of the target port for which the
+		 * secondary target port asymmetric access state shall be
+		 * changed.
+		 */
+		if (primary) {
+			tg_pt_id = ((ptr[2] << 8) & 0xff);
+			tg_pt_id |= (ptr[3] & 0xff);
+			/*
+			 * Locate the matching target port group ID from
+			 * the global tg_pt_gp list
+			 */
+			spin_lock(&T10_ALUA(su_dev)->tg_pt_gps_lock);
+			list_for_each_entry(tg_pt_gp,
+					&T10_ALUA(su_dev)->tg_pt_gps_list,
+					tg_pt_gp_list) {
+				if (!(tg_pt_gp->tg_pt_gp_valid_id))
+					continue;
+
+				if (tg_pt_id != tg_pt_gp->tg_pt_gp_id)
+					continue;
+
+				atomic_inc(&tg_pt_gp->tg_pt_gp_ref_cnt);
+				smp_mb__after_atomic_inc();
+				spin_unlock(&T10_ALUA(su_dev)->tg_pt_gps_lock);
+
+				rc = core_alua_do_port_transition(tg_pt_gp,
+						dev, l_port, nacl,
+						alua_access_state, 1);
+
+				spin_lock(&T10_ALUA(su_dev)->tg_pt_gps_lock);
+				atomic_dec(&tg_pt_gp->tg_pt_gp_ref_cnt);
+				smp_mb__after_atomic_dec();
+				break;
+			}
+			spin_unlock(&T10_ALUA(su_dev)->tg_pt_gps_lock);
+			/*
+			 * If not matching target port group ID can be located
+			 * throw an exception with ASCQ: INVALID_PARAMETER_LIST
+			 */
+			if (rc != 0)
+				return PYX_TRANSPORT_INVALID_PARAMETER_LIST;
+		} else {
+			/*
+			 * Extact the RELATIVE TARGET PORT IDENTIFIER to identify
+			 * the Target Port in question for the the incoming
+			 * SET_TARGET_PORT_GROUPS op.
+			 */
+			rtpi = ((ptr[2] << 8) & 0xff);
+			rtpi |= (ptr[3] & 0xff);
+			/*
+			 * Locate the matching relative target port identifer
+			 * for the struct se_device storage object.
+			 */
+			spin_lock(&dev->se_port_lock);
+			list_for_each_entry(port, &dev->dev_sep_list,
+							sep_list) {
+				if (port->sep_rtpi != rtpi)
+					continue;
+
+				tg_pt_gp_mem = port->sep_alua_tg_pt_gp_mem;
+				spin_unlock(&dev->se_port_lock);
+
+				rc = core_alua_set_tg_pt_secondary_state(
+						tg_pt_gp_mem, port, 1, 1);
+
+				spin_lock(&dev->se_port_lock);
+				break;
+			}
+			spin_unlock(&dev->se_port_lock);
+			/*
+			 * If not matching relative target port identifier can
+			 * be located, throw an exception with ASCQ:
+			 * INVALID_PARAMETER_LIST
+			 */
+			if (rc != 0)
+				return PYX_TRANSPORT_INVALID_PARAMETER_LIST;
+		}
+
+		ptr += 4;
+		len += 4;
+	}
+
+	return 0;
+}
+
+static inline int core_alua_state_nonoptimized(
+	struct se_cmd *cmd,
+	unsigned char *cdb,
+	int nonop_delay_msecs,
+	u8 *alua_ascq)
+{
+	/*
+	 * Set SCF_ALUA_NON_OPTIMIZED here, this value will be checked
+	 * later to determine if processing of this cmd needs to be
+	 * temporarily delayed for the Active/NonOptimized primary access state.
+	 */
+	cmd->se_cmd_flags |= SCF_ALUA_NON_OPTIMIZED;
+	cmd->alua_nonop_delay = nonop_delay_msecs;
+	return 0;
+}
+
+static inline int core_alua_state_standby(
+	struct se_cmd *cmd,
+	unsigned char *cdb,
+	u8 *alua_ascq)
+{
+	/*
+	 * Allowed CDBs for ALUA_ACCESS_STATE_STANDBY as defined by
+	 * spc4r17 section 5.9.2.4.4
+	 */
+	switch (cdb[0]) {
+	case INQUIRY:
+	case LOG_SELECT:
+	case LOG_SENSE:
+	case MODE_SELECT:
+	case MODE_SENSE:
+	case REPORT_LUNS:
+	case RECEIVE_DIAGNOSTIC:
+	case SEND_DIAGNOSTIC:
+	case MAINTENANCE_IN:
+		switch (cdb[1]) {
+		case MI_REPORT_TARGET_PGS:
+			return 0;
+		default:
+			*alua_ascq = ASCQ_04H_ALUA_TG_PT_STANDBY;
+			return 1;
+		}
+	case MAINTENANCE_OUT:
+		switch (cdb[1]) {
+		case MO_SET_TARGET_PGS:
+			return 0;
+		default:
+			*alua_ascq = ASCQ_04H_ALUA_TG_PT_STANDBY;
+			return 1;
+		}
+	case REQUEST_SENSE:
+	case PERSISTENT_RESERVE_IN:
+	case PERSISTENT_RESERVE_OUT:
+	case READ_BUFFER:
+	case WRITE_BUFFER:
+		return 0;
+	default:
+		*alua_ascq = ASCQ_04H_ALUA_TG_PT_STANDBY;
+		return 1;
+	}
+
+	return 0;
+}
+
+static inline int core_alua_state_unavailable(
+	struct se_cmd *cmd,
+	unsigned char *cdb,
+	u8 *alua_ascq)
+{
+	/*
+	 * Allowed CDBs for ALUA_ACCESS_STATE_UNAVAILABLE as defined by
+	 * spc4r17 section 5.9.2.4.5
+	 */
+	switch (cdb[0]) {
+	case INQUIRY:
+	case REPORT_LUNS:
+	case MAINTENANCE_IN:
+		switch (cdb[1]) {
+		case MI_REPORT_TARGET_PGS:
+			return 0;
+		default:
+			*alua_ascq = ASCQ_04H_ALUA_TG_PT_UNAVAILABLE;
+			return 1;
+		}
+	case MAINTENANCE_OUT:
+		switch (cdb[1]) {
+		case MO_SET_TARGET_PGS:
+			return 0;
+		default:
+			*alua_ascq = ASCQ_04H_ALUA_TG_PT_UNAVAILABLE;
+			return 1;
+		}
+	case REQUEST_SENSE:
+	case READ_BUFFER:
+	case WRITE_BUFFER:
+		return 0;
+	default:
+		*alua_ascq = ASCQ_04H_ALUA_TG_PT_UNAVAILABLE;
+		return 1;
+	}
+
+	return 0;
+}
+
+static inline int core_alua_state_transition(
+	struct se_cmd *cmd,
+	unsigned char *cdb,
+	u8 *alua_ascq)
+{
+	/*
+	 * Allowed CDBs for ALUA_ACCESS_STATE_TRANSITIO as defined by
+	 * spc4r17 section 5.9.2.5
+	 */
+	switch (cdb[0]) {
+	case INQUIRY:
+	case REPORT_LUNS:
+	case MAINTENANCE_IN:
+		switch (cdb[1]) {
+		case MI_REPORT_TARGET_PGS:
+			return 0;
+		default:
+			*alua_ascq = ASCQ_04H_ALUA_STATE_TRANSITION;
+			return 1;
+		}
+	case REQUEST_SENSE:
+	case READ_BUFFER:
+	case WRITE_BUFFER:
+		return 0;
+	default:
+		*alua_ascq = ASCQ_04H_ALUA_STATE_TRANSITION;
+		return 1;
+	}
+
+	return 0;
+}
+
+/*
+ * Used for alua_type SPC_ALUA_PASSTHROUGH and SPC2_ALUA_DISABLED
+ * in transport_cmd_sequencer().  This function is assigned to
+ * struct t10_alua *->state_check() in core_setup_alua()
+ */
+static int core_alua_state_check_nop(
+	struct se_cmd *cmd,
+	unsigned char *cdb,
+	u8 *alua_ascq)
+{
+	return 0;
+}
+
+/*
+ * Used for alua_type SPC3_ALUA_EMULATED in transport_cmd_sequencer().
+ * This function is assigned to struct t10_alua *->state_check() in
+ * core_setup_alua()
+ *
+ * Also, this function can return three different return codes to
+ * signal transport_generic_cmd_sequencer()
+ *
+ * return 1: Is used to signal LUN not accecsable, and check condition/not ready
+ * return 0: Used to signal success
+ * reutrn -1: Used to signal failure, and invalid cdb field
+ */
+static int core_alua_state_check(
+	struct se_cmd *cmd,
+	unsigned char *cdb,
+	u8 *alua_ascq)
+{
+	struct se_lun *lun = SE_LUN(cmd);
+	struct se_port *port = lun->lun_sep;
+	struct t10_alua_tg_pt_gp *tg_pt_gp;
+	struct t10_alua_tg_pt_gp_member *tg_pt_gp_mem;
+	int out_alua_state, nonop_delay_msecs;
+
+	if (!(port))
+		return 0;
+	/*
+	 * First, check for a struct se_port specific secondary ALUA target port
+	 * access state: OFFLINE
+	 */
+	if (atomic_read(&port->sep_tg_pt_secondary_offline)) {
+		*alua_ascq = ASCQ_04H_ALUA_OFFLINE;
+		printk(KERN_INFO "ALUA: Got secondary offline status for local"
+				" target port\n");
+		*alua_ascq = ASCQ_04H_ALUA_OFFLINE;
+		return 1;
+	}
+	 /*
+	 * Second, obtain the struct t10_alua_tg_pt_gp_member pointer to the
+	 * ALUA target port group, to obtain current ALUA access state.
+	 * Otherwise look for the underlying struct se_device association with
+	 * a ALUA logical unit group.
+	 */
+	tg_pt_gp_mem = port->sep_alua_tg_pt_gp_mem;
+	spin_lock(&tg_pt_gp_mem->tg_pt_gp_mem_lock);
+	tg_pt_gp = tg_pt_gp_mem->tg_pt_gp;
+	out_alua_state = atomic_read(&tg_pt_gp->tg_pt_gp_alua_access_state);
+	nonop_delay_msecs = tg_pt_gp->tg_pt_gp_nonop_delay_msecs;
+	spin_unlock(&tg_pt_gp_mem->tg_pt_gp_mem_lock);
+	/*
+	 * Process ALUA_ACCESS_STATE_ACTIVE_OPTMIZED in a seperate conditional
+	 * statement so the complier knows explictly to check this case first.
+	 * For the Optimized ALUA access state case, we want to process the
+	 * incoming fabric cmd ASAP..
+	 */
+	if (out_alua_state == ALUA_ACCESS_STATE_ACTIVE_OPTMIZED)
+		return 0;
+
+	switch (out_alua_state) {
+	case ALUA_ACCESS_STATE_ACTIVE_NON_OPTIMIZED:
+		return core_alua_state_nonoptimized(cmd, cdb,
+					nonop_delay_msecs, alua_ascq);
+	case ALUA_ACCESS_STATE_STANDBY:
+		return core_alua_state_standby(cmd, cdb, alua_ascq);
+	case ALUA_ACCESS_STATE_UNAVAILABLE:
+		return core_alua_state_unavailable(cmd, cdb, alua_ascq);
+	case ALUA_ACCESS_STATE_TRANSITION:
+		return core_alua_state_transition(cmd, cdb, alua_ascq);
+	/*
+	 * OFFLINE is a secondary ALUA target port group access state, that is
+	 * handled above with struct se_port->sep_tg_pt_secondary_offline=1
+	 */
+	case ALUA_ACCESS_STATE_OFFLINE:
+	default:
+		printk(KERN_ERR "Unknown ALUA access state: 0x%02x\n",
+				out_alua_state);
+		return -1;
+	}
+
+	return 0;
+}
+
+/*
+ * Check implict and explict ALUA state change request.
+ */
+static int core_alua_check_transition(int state, int *primary)
+{
+	switch (state) {
+	case ALUA_ACCESS_STATE_ACTIVE_OPTMIZED:
+	case ALUA_ACCESS_STATE_ACTIVE_NON_OPTIMIZED:
+	case ALUA_ACCESS_STATE_STANDBY:
+	case ALUA_ACCESS_STATE_UNAVAILABLE:
+		/*
+		 * OPTIMIZED, NON-OPTIMIZED, STANDBY and UNAVAILABLE are
+		 * defined as primary target port asymmetric access states.
+		 */
+		*primary = 1;
+		break;
+	case ALUA_ACCESS_STATE_OFFLINE:
+		/*
+		 * OFFLINE state is defined as a secondary target port
+		 * asymmetric access state.
+		 */
+		*primary = 0;
+		break;
+	default:
+		printk(KERN_ERR "Unknown ALUA access state: 0x%02x\n", state);
+		return -1;
+	}
+
+	return 0;
+}
+
+static char *core_alua_dump_state(int state)
+{
+	switch (state) {
+	case ALUA_ACCESS_STATE_ACTIVE_OPTMIZED:
+		return "Active/Optimized";
+	case ALUA_ACCESS_STATE_ACTIVE_NON_OPTIMIZED:
+		return "Active/NonOptimized";
+	case ALUA_ACCESS_STATE_STANDBY:
+		return "Standby";
+	case ALUA_ACCESS_STATE_UNAVAILABLE:
+		return "Unavailable";
+	case ALUA_ACCESS_STATE_OFFLINE:
+		return "Offline";
+	default:
+		return "Unknown";
+	}
+
+	return NULL;
+}
+
+char *core_alua_dump_status(int status)
+{
+	switch (status) {
+	case ALUA_STATUS_NONE:
+		return "None";
+	case ALUA_STATUS_ALTERED_BY_EXPLICT_STPG:
+		return "Altered by Explict STPG";
+	case ALUA_STATUS_ALTERED_BY_IMPLICT_ALUA:
+		return "Altered by Implict ALUA";
+	default:
+		return "Unknown";
+	}
+
+	return NULL;
+}
+
+/*
+ * Used by fabric modules to determine when we need to delay processing
+ * for the Active/NonOptimized paths..
+ */
+int core_alua_check_nonop_delay(
+	struct se_cmd *cmd)
+{
+	if (!(cmd->se_cmd_flags & SCF_ALUA_NON_OPTIMIZED))
+		return 0;
+	if (in_interrupt())
+		return 0;
+	/*
+	 * The ALUA Active/NonOptimized access state delay can be disabled
+	 * in via configfs with a value of zero
+	 */
+	if (!(cmd->alua_nonop_delay))
+		return 0;
+	/*
+	 * struct se_cmd->alua_nonop_delay gets set by a target port group
+	 * defined interval in core_alua_state_nonoptimized()
+	 */
+	msleep_interruptible(cmd->alua_nonop_delay);
+	return 0;
+}
+EXPORT_SYMBOL(core_alua_check_nonop_delay);
+
+/*
+ * Called with tg_pt_gp->tg_pt_gp_md_mutex or tg_pt_gp_mem->sep_tg_pt_md_mutex
+ *
+ */
+static int core_alua_write_tpg_metadata(
+	const char *path,
+	unsigned char *md_buf,
+	u32 md_buf_len)
+{
+	mm_segment_t old_fs;
+	struct file *file;
+	struct iovec iov[1];
+	int flags = O_RDWR | O_CREAT | O_TRUNC, ret;
+
+	memset(iov, 0, sizeof(struct iovec));
+
+	file = filp_open(path, flags, 0600);
+	if (IS_ERR(file) || !file || !file->f_dentry) {
+		printk(KERN_ERR "filp_open(%s) for ALUA metadata failed\n",
+			path);
+		return -ENODEV;
+	}
+
+	iov[0].iov_base = &md_buf[0];
+	iov[0].iov_len = md_buf_len;
+
+	old_fs = get_fs();
+	set_fs(get_ds());
+	ret = vfs_writev(file, &iov[0], 1, &file->f_pos);
+	set_fs(old_fs);
+
+	if (ret < 0) {
+		printk(KERN_ERR "Error writing ALUA metadata file: %s\n", path);
+		filp_close(file, NULL);
+		return -EIO;
+	}
+	filp_close(file, NULL);
+
+	return 0;
+}
+
+/*
+ * Called with tg_pt_gp->tg_pt_gp_md_mutex held
+ */
+static int core_alua_update_tpg_primary_metadata(
+	struct t10_alua_tg_pt_gp *tg_pt_gp,
+	int primary_state,
+	unsigned char *md_buf)
+{
+	struct se_subsystem_dev *su_dev = tg_pt_gp->tg_pt_gp_su_dev;
+	struct t10_wwn *wwn = &su_dev->t10_wwn;
+	char path[ALUA_METADATA_PATH_LEN];
+	int len;
+
+	memset(path, 0, ALUA_METADATA_PATH_LEN);
+
+	len = snprintf(md_buf, tg_pt_gp->tg_pt_gp_md_buf_len,
+			"tg_pt_gp_id=%hu\n"
+			"alua_access_state=0x%02x\n"
+			"alua_access_status=0x%02x\n",
+			tg_pt_gp->tg_pt_gp_id, primary_state,
+			tg_pt_gp->tg_pt_gp_alua_access_status);
+
+	snprintf(path, ALUA_METADATA_PATH_LEN,
+		"/var/target/alua/tpgs_%s/%s", &wwn->unit_serial[0],
+		config_item_name(&tg_pt_gp->tg_pt_gp_group.cg_item));
+
+	return core_alua_write_tpg_metadata(path, md_buf, len);
+}
+
+static int core_alua_do_transition_tg_pt(
+	struct t10_alua_tg_pt_gp *tg_pt_gp,
+	struct se_port *l_port,
+	struct se_node_acl *nacl,
+	unsigned char *md_buf,
+	int new_state,
+	int explict)
+{
+	struct se_dev_entry *se_deve;
+	struct se_lun_acl *lacl;
+	struct se_port *port;
+	struct t10_alua_tg_pt_gp_member *mem;
+	int old_state = 0;
+	/*
+	 * Save the old primary ALUA access state, and set the current state
+	 * to ALUA_ACCESS_STATE_TRANSITION.
+	 */
+	old_state = atomic_read(&tg_pt_gp->tg_pt_gp_alua_access_state);
+	atomic_set(&tg_pt_gp->tg_pt_gp_alua_access_state,
+			ALUA_ACCESS_STATE_TRANSITION);
+	tg_pt_gp->tg_pt_gp_alua_access_status = (explict) ?
+				ALUA_STATUS_ALTERED_BY_EXPLICT_STPG :
+				ALUA_STATUS_ALTERED_BY_IMPLICT_ALUA;
+	/*
+	 * Check for the optional ALUA primary state transition delay
+	 */
+	if (tg_pt_gp->tg_pt_gp_trans_delay_msecs != 0)
+		msleep_interruptible(tg_pt_gp->tg_pt_gp_trans_delay_msecs);
+
+	spin_lock(&tg_pt_gp->tg_pt_gp_lock);
+	list_for_each_entry(mem, &tg_pt_gp->tg_pt_gp_mem_list,
+				tg_pt_gp_mem_list) {
+		port = mem->tg_pt;
+		/*
+		 * After an implicit target port asymmetric access state
+		 * change, a device server shall establish a unit attention
+		 * condition for the initiator port associated with every I_T
+		 * nexus with the additional sense code set to ASYMMETRIC
+		 * ACCESS STATE CHAGED.
+		 *
+		 * After an explicit target port asymmetric access state
+		 * change, a device server shall establish a unit attention
+		 * condition with the additional sense code set to ASYMMETRIC
+		 * ACCESS STATE CHANGED for the initiator port associated with
+		 * every I_T nexus other than the I_T nexus on which the SET
+		 * TARGET PORT GROUPS command
+		 */
+		atomic_inc(&mem->tg_pt_gp_mem_ref_cnt);
+		smp_mb__after_atomic_inc();
+		spin_unlock(&tg_pt_gp->tg_pt_gp_lock);
+
+		spin_lock_bh(&port->sep_alua_lock);
+		list_for_each_entry(se_deve, &port->sep_alua_list,
+					alua_port_list) {
+			lacl = se_deve->se_lun_acl;
+			/*
+			 * se_deve->se_lun_acl pointer may be NULL for a
+			 * entry created without explict Node+MappedLUN ACLs
+			 */
+			if (!(lacl))
+				continue;
+
+			if (explict &&
+			   (nacl != NULL) && (nacl == lacl->se_lun_nacl) &&
+			   (l_port != NULL) && (l_port == port))
+				continue;
+
+			core_scsi3_ua_allocate(lacl->se_lun_nacl,
+				se_deve->mapped_lun, 0x2A,
+				ASCQ_2AH_ASYMMETRIC_ACCESS_STATE_CHANGED);
+		}
+		spin_unlock_bh(&port->sep_alua_lock);
+</