Documentation/target: add an example script to configure an iSCSI target

Commit Message

Christophe Vu-Brugier April 12, 2017, 7:59 p.m. UTC

The script illustrates how to interact with configfs to create a very
simple LIO iSCSI target with a file or block device backstore.

The script can serve as a starting point for people that cannot use
targetcli because Python is not available on their machine.

Signed-off-by: Christophe Vu-Brugier <[e-mail]>
Signed-off-by: Vincent Donnefort <[e-mail]>
---
 Documentation/target/target-export-device | 80 +++++++++++++++++++++++++++++++
 1 file changed, 80 insertions(+)
 create mode 100755 Documentation/target/target-export-device

Comments

Nicholas A. Bellinger May 2, 2017, 4:20 a.m. UTC | #1

Hi Christophe,

Apologies for the delayed follow up.

On Wed, 2017-04-12 at 21:59 +0200, Christophe Vu-Brugier wrote:
> The script illustrates how to interact with configfs to create a very
> simple LIO iSCSI target with a file or block device backstore.
> 
> The script can serve as a starting point for people that cannot use
> targetcli because Python is not available on their machine.
> 
> Signed-off-by: Christophe Vu-Brugier <[e-mail]>
> Signed-off-by: Vincent Donnefort <[e-mail]>

Applied.

Thank you.

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Patch

diff --git a/Documentation/target/target-export-device b/Documentation/target/target-export-device
new file mode 100755
index 000000000000..b803f4f886b5
--- /dev/null
+++ b/Documentation/target/target-export-device
@@ -0,0 +1,80 @@ 
+#!/bin/sh
+#
+# This script illustrates the sequence of operations in configfs to
+# create a very simple LIO iSCSI target with a file or block device
+# backstore.
+#
+# (C) Copyright 2014 Christophe Vu-Brugier <[e-mail]>
+#
+
+print_usage() {
+    cat <<EOF
+Usage: $(basename $0) [-p PORTAL] DEVICE|FILE
+Export a block device or a file as an iSCSI target with a single LUN
+EOF
+}
+
+die() {
+    echo $1
+    exit 1
+}
+
+while getopts "hp:" arg; do
+    case $arg in
+        h) print_usage; exit 0;;
+        p) PORTAL=${OPTARG};;
+    esac
+done
+shift $(($OPTIND - 1))
+
+DEVICE=$1
+[ -n "$DEVICE" ] || die "Missing device or file argument"
+[ -b $DEVICE -o -f $DEVICE ] || die "Invalid device or file: ${DEVICE}"
+IQN="iqn.2003-01.org.linux-iscsi.$(hostname):$(basename $DEVICE)"
+[ -n "$PORTAL" ] || PORTAL="0.0.0.0:3260"
+
+CONFIGFS=/sys/kernel/config
+CORE_DIR=$CONFIGFS/target/core
+ISCSI_DIR=$CONFIGFS/target/iscsi
+
+# Load the target modules and mount the config file system
+lsmod | grep -q configfs || modprobe configfs
+lsmod | grep -q target_core_mod || modprobe target_core_mod
+mount | grep -q ^configfs || mount -t configfs none $CONFIGFS
+mkdir -p $ISCSI_DIR
+
+# Create a backstore
+if [ -b $DEVICE ]; then
+    BACKSTORE_DIR=$CORE_DIR/iblock_0/data
+    mkdir -p $BACKSTORE_DIR
+    echo "udev_path=${DEVICE}" > $BACKSTORE_DIR/control
+else
+    BACKSTORE_DIR=$CORE_DIR/fileio_0/data
+    mkdir -p $BACKSTORE_DIR
+    DEVICE_SIZE=$(du -b $DEVICE | cut -f1)
+    echo "fd_dev_name=${DEVICE}" > $BACKSTORE_DIR/control
+    echo "fd_dev_size=${DEVICE_SIZE}" > $BACKSTORE_DIR/control
+    echo 1 > $BACKSTORE_DIR/attrib/emulate_write_cache
+fi
+echo 1 > $BACKSTORE_DIR/enable
+
+# Create an iSCSI target and a target portal group (TPG)
+mkdir $ISCSI_DIR/$IQN
+mkdir $ISCSI_DIR/$IQN/tpgt_1/
+
+# Create a LUN
+mkdir $ISCSI_DIR/$IQN/tpgt_1/lun/lun_0
+ln -s $BACKSTORE_DIR $ISCSI_DIR/$IQN/tpgt_1/lun/lun_0/data
+echo 1 > $ISCSI_DIR/$IQN/tpgt_1/enable
+
+# Create a network portal
+mkdir $ISCSI_DIR/$IQN/tpgt_1/np/$PORTAL
+
+# Disable authentication
+echo 0 > $ISCSI_DIR/$IQN/tpgt_1/attrib/authentication
+echo 1 > $ISCSI_DIR/$IQN/tpgt_1/attrib/generate_node_acls
+
+# Allow write access for non authenticated initiators
+echo 0 > $ISCSI_DIR/$IQN/tpgt_1/attrib/demo_mode_write_protect
+
+echo "Target ${IQN}, portal ${PORTAL} has been created"