From 4654b9d2053321cf369e60eba6f3e79b92292589 Mon Sep 17 00:00:00 2001
From: Simon Rettberg
Date: Wed, 30 Sep 2020 08:56:35 +0200
Subject: [slx-dmsetup] Simplifications, comments

---
 modules.d/slx-dmsetup/scripts/dmsetup-slx-device | 54 +++++++++++++++---------
 1 file changed, 33 insertions(+), 21 deletions(-)

diff --git a/modules.d/slx-dmsetup/scripts/dmsetup-slx-device b/modules.d/slx-dmsetup/scripts/dmsetup-slx-device
index 5caeafb7..4085b1cf 100755
--- a/modules.d/slx-dmsetup/scripts/dmsetup-slx-device
+++ b/modules.d/slx-dmsetup/scripts/dmsetup-slx-device
@@ -15,6 +15,7 @@
 # NOTE: Encrypting thin-snapshot will actually encrypt the
 # entire pool data device used for the pool.
 # TODO: Support external keys
+# TODO: Put table in file in config.tgz
 
 type -p emergency_shell || . /lib/dracut-lib.sh
 
@@ -85,7 +86,13 @@ parse_config() {
 			crypt=0
 		fi
 		# finally save it to the global array for this type
-		eval "${type}"'+=("'"${name} ${crypt} ${min} ${max}"'")'
+		case "$type" in
+			linear) linear+=("${name} ${crypt} ${min} ${max}") ;;
+			snapshot) snapshot+=("${name} ${crypt} ${min} ${max}") ;;
+			thin_snapshot) thin_snapshot+=("${name} ${crypt} ${min} ${max}") ;;
+			thin_volume) thin_volume+=("${name} ${crypt} ${min} ${max}") ;;
+			*) echo "$0: SOMETHING NOT GOOT CHECK SOURCE CODE" ;;
+		esac
 	done <<< "$1"
 }
 
@@ -201,10 +208,10 @@ finish_setup() {
 		emergency_shell "'$2' not a valid type, 0 or 1 expected."
 	fi
 	# <size> optional?
-	(
-	echo "# Generated by '$0'." 
+	{
+	echo "# Generated by '$0'."
 	echo "SLX_DNBD3_DEVICE_COW=/dev/mapper/$1"
-	) >> /etc/openslx
+	} >> /etc/openslx
 	save_partition_info "$1" "/" "$2" "$3"
 	exit 0
 }
@@ -224,7 +231,7 @@ save_partition_info() {
 	[ -b "/dev/mapper/$1" ] || return 1
 	[ -n "$2" ] || return 1
 	[[ "$3" =~ ^[0-9]$ ]] || return 1
-        local opts="type=$3"
+	local opts="type=$3"
 	# plain size given
 	[[ "$4" =~ ^[0-9]+$ ]] && opts="$opts,physical_size=$4"
 	# <physical_backing_dev_size>-<virtual_size>
@@ -326,12 +333,12 @@ fi
 writable_device_allocated="$scratch_device_size"
 
 # first setup linear slices of the writable device
-for i in "${!linear[@]}"; do
-	[ -z "${linear[$i]}" ] && continue
-	read -r name crypt min max ignore <<< "${linear[$i]}"
+for line in "${linear[@]}"; do
+	[ -z "$line" ] && continue
+	read -r name crypt min max ignore <<< "$line"
 	free_space="$(( writable_device_size - writable_device_allocated ))"
 	if [ "$min" -gt "$free_space" ]; then
-		echo "$0: Not enough space left for linear devices: ${linear[$i]}"
+		echo "$0: Not enough space left for linear devices: '$line'"
 		break
 	fi
 	# allocate its max if it fits within the free space, otherwise use the space left.
@@ -339,7 +346,7 @@ for i in "${!linear[@]}"; do
 	[ "$to_allocate" -gt "$free_space" ] && to_allocate="$free_space"
 
 	if ! dmsetup_create_noudevsync "$name" "0 $to_allocate linear $writable_device $writable_device_allocated"; then
-		echo "$0: Failed to create linear device: ${linear[$i]}"
+		echo "$0: Failed to create linear device: $line"
 		continue
 	fi
 	# TODO sane?
@@ -415,18 +422,20 @@ create_pool() {
 	return 0
 }
 
-# create_volume "<name> <id> <size> <backing_dev>"
+# create_volume <name> <id> <size> [backing_dev]
 create_volume() {
 	if [ -z "$pool_dev" ] || ! [ -b "$pool_dev" ]; then
 		echo "$0: Global pool device not set or present."
 		return 1
 	fi
-	if [ $# -ne 1 ] || [ -z "$1" ]; then
-		echo "$0: create_volume requires one non-empty argument."
+	if [ $# -lt 3 ] || [ -z "$1" ]; then
+		echo "$0: create_volume: not enough arguments."
 		return 1
 	fi
-	local name id size backing_dev ignore
-	read -r name id size backing_dev ignore <<< "$1"
+	local name="$1"
+	local id="$2"
+	local size="$3"
+	local backing_dev="$4" # Optional, internal if empty
 
 	if ! dmsetup message "$pool_dev" 0 "create_thin $id"; then
 		echo "$0: Failed to create thin volume with id '$id' in pool '$pool_dev'."
@@ -441,6 +450,9 @@ create_volume() {
 	fi
 	return 0
 }
+
+# Now decide what to do for the writable layer
+
 if [ -n "$thin_snapshot" ] || [ -n "$thin_volume" ]; then
 	if ! create_pool ; then
 		echo "Failed to create thin pool. Will ignore:"
@@ -453,12 +465,12 @@ if [ -n "$thin_snapshot" ] || [ -n "$thin_volume" ]; then
 	# the thin-snapshot with id 1 which needs to call finish_setup.
 	volume_id=2
 	# go over thin-volumes
-	for i in "${!thin_volume[@]}"; do
-		[ -z "${thin_volume[$i]}" ] && continue
-		read -r name crypt min max ignore <<< "${thin_volume[$i]}"
-		# thin-volume can be safely created with max size,
+	for line in "${thin_volume[@]}"; do
+		[ -z "$line" ] && continue
+		read -r name crypt min max ignore <<< "$line"
+		# thin-volume can be created with max size,
 		# since they are overprovisioned anyway.
-		if ! create_volume "$name $(( volume_id++ )) $max"; then
+		if ! create_volume "$name" "$(( volume_id++ ))" "$max"; then
 			echo "Failed to create thin volume '$name'."
 		fi
 		save_partition_info "$name" "*" "1" "${writable_device_size}-${max}"
@@ -483,7 +495,7 @@ if [ -n "$thin_snapshot" ] || [ -n "$thin_volume" ]; then
 		else
 			thin_snapshot_size="$read_only_device_size"
 		fi
-		if ! create_volume "$name 1 $thin_snapshot_size $read_only_device"; then
+		if ! create_volume "$name" 1 "$thin_snapshot_size" "$read_only_device"; then
 			echo "Failed to create external snapshot for '$read_only_device'."
 			ramdisk_fallback
 		fi
-- 
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