Update partition shrink function

archlabs-installer

@@ -5,7 +5,7 @@
 # Some ideas and code reworked from other resources
 # AIF, Cnichi, Calamares, Arch Wiki.. Credit where credit is due
 
-VER="2.0.36"     # installer version
+VER="2.0.40"     # installer version
 DIST="ArchLabs"  # linux distributor
 MNT="/mnt"       # install mountpoint
 ANS="/tmp/ans"   # dialog answer file
@@ -717,7 +717,7 @@ part_menu()
 		if [[ $DISPLAY && $TERM != 'linux' ]] && hash gparted >/dev/null 2>&1; then
 			dlg choice menu "Edit Partitions" "$_part" \
 				"auto"    "Whole device automatic partitioning" \
-				"resize"  "Resize an existing ext2/3/4 or ntfs partition" \
+				"shrink"  "Shrink an existing ext2/3/4 or ntfs partition to make room for a new partition" \
 				"gparted" "GUI front end to parted" \
 				"cfdisk"  "Curses based variant of fdisk" \
 				"parted"  "GNU partition editor" \
@@ -726,7 +726,7 @@ part_menu()
 		else
 			dlg choice menu "Edit Partitions" "$_part" \
 				"auto"   "Whole device automatic partitioning" \
-				"resize" "Resize an existing ext2/3/4 or ntfs partition" \
+				"shrink" "Shrink an existing ext2/3/4 or ntfs partition to make room for a new partition" \
 				"cfdisk" "Curses based variant of fdisk" \
 				"parted" "GNU partition editor" \
 				"fdisk"  "Dialog-driven creation and manipulation of partitions" \
@@ -735,8 +735,8 @@ part_menu()
 
 		if [[ $choice == 'done' ]]; then
 			return 0
-		elif [[ $choice == 'resize' ]]; then
+		elif [[ $choice == 'shrink' ]]; then
-			part_resize "$device"
+			part_shrink "$device"
 		elif [[ $choice == 'auto' ]]; then
 			local root_size txt table boot_fs
 			root_size=$(lsblk -lno SIZE "$device" | awk 'NR == 1 {
@@ -906,7 +906,7 @@ part_format()
 	sleep "${delay:-0}"
 }
 
-part_resize()
+part_shrink()
 {
 	part=""
 	typeset -i size num
@@ -921,20 +921,26 @@ part_resize()
 			ext*|ntfs)
 				msg "Resize" "\nGathering device size info.\n" 0
 
-				# shit hacks to get device size info
+				# get device size info
 				num="${part: -1}"
-				end=$(parted -s "$device" print | awk '/^\s*'"$num"'/ {print $3}')
+				end=$(parted -s "$device" unit KiB print | awk '/^\s*'"$num"'/ {print int($3)}')                    # part size in KiB
-				devsize=$(parted -s "$device" print | awk '/Disk '"${device//\//\\/}"':/ {print $3}')
+				devsize=$(parted -s "$device" unit KiB print | awk '/Disk '"${device//\//\\/}"':/ {print int($3)}') # whole device size in KiB
-				mount "$part" $MNT >/dev/null 2>&1; sleep 0.5
+
-				min=$(df "$part" | awk '/'"${part//\//\\/}"'/ {print int($3 / 1024)}') # used
+				# minimum in KiB (2^10)
-				max=$(df "$part" | awk '/'"${part//\//\\/}"'/ {print int($4 / 1024)}') # available
+				case "$fs" in
-				umount $MNT >/dev/null 2>&1
+					ext[2-4]) min=$(dumpe2fs -h "$part" |& awk '/Block count/{count=$NF} /Block size/{size=$NF} END{print int((count * size) / 1024)}') ;;
+					ntfs) min=$(ntfsresize -f -m "$part" | awk 'NR == 2 {print int(($NF * 1000 * 1000) / 1024)}') ;;
+				esac
+
+				# KiB -> MiB
+				mbmin=$((min / 1024))
+				mbend=$((end / 1024))
 
 				# get new size from user
 				tput cnorm
-				if dialog --backtitle "$DIST Installer - $SYS - v$VER" --title " Resize: $part " --rangebox "$_resize" 17 "$COLUMNS" "$min" "$max" $((max / 2)) 2>$ANS; then
+				if dialog --backtitle "$DIST Installer - $SYS - v$VER" --title " Resize: $part " --rangebox "$_resize" 17 "$COLUMNS" "$mbmin" "$mbend" $((mbend / 2)) 2>$ANS; then
-					(( (size = $(< "$ANS")) + 1025 <= max )) || return 1
+					(( (size = $(< "$ANS")) < mbend )) || return 1
-					size=$((( (size * 1024) / 4 ) * 4)) # 4K block alignment
+					size=$((size * 1024))
 				else
 					return 1
 				fi
@@ -943,28 +949,31 @@ part_resize()
 				case "$fs" in
 					ext[2-4])
 						e2fsck -f "$part"; sleep 0.5
-						resize2fs -f "$part" ${size}K 2>$ERR
+						resize2fs -f "$part" ${size}K 2>$ERR # K=2^10 bytes
-						errshow "resize2fs -f $part ${size}K" { echo 'press enter to continue'; read; return 1; }
+						errshow "resize2fs -f $part ${size}K" || return 1
+						;;
+					ntfs)
+						ntfsresize -fc "$part" || { msg "Resize" "\nThe ntfs partition $part cannot be resized because it is scheduled for a consistency check.\n\nTo do a consistency check in windows open command prompt as admin and run:\n\n\tchkdsk /f /r /x\n"; return 1; }
+						ntfsresize -ff --size $(( (size * 1024) / 1000 ))k "$part" 2>$ERR # k=10^3 bytes
+						errshow "ntfsresize -f -s $(( (size * 1024) / 1000 ))k $part" || return 1
 						;;
-					ntfs) ntfsresize -f -s ${size}k "$part" || { echo 'press enter to continue'; read; return 1; } ;;
 				esac
 
+				echo "filesystem shrunk successfully, now the partition"
 				sleep 0.5
-				(( size += 1024 ))
+				parted "$device" resizepart "$num" ${size}KiB || return 1
-				parted "$device" resizepart "$num" ${size}Kib || return 1
+				(( size++ ))
 				sleep 0.5
 
-				if (( ++size < (max * 1024) )); then
 				if [[ $devsize == "$end" ]]; then
-						parted -s "$device" mkpart primary ext4 ${size}Kib 100% 2>$ERR
+					parted -s "$device" mkpart primary ext4 ${size}KiB 100% 2>$ERR
+					errshow "parted -s $device mkpart primary ext4 ${size}KiB 100%" || return 1
 				else
-						parted -s "$device" mkpart primary ext4 ${size}Kib "$end" 2>$ERR
+					parted -s "$device" mkpart primary ext4 ${size}KiB ${end}KiB 2>$ERR
-					fi
+					errshow "parted -s $device mkpart primary ext4 ${size}KiB ${end}KiB" || return 1
-					errshow "parted -s $device mkpart primary ext4 ${size}Kib 100%" || return 1
 				fi
 
-				sleep 1
+				msg "Resize Complete" "\n$part has been successfully resized to $((size / 1024))M.\n"
-				msg "Resize Complete" "\n$part has been successfully resized to $(( (size - 1025) / 1024 ))M.\n"
 				;;
 			*) msg "Invalid Filesystem: $fs" "\nResizing only supports ext and ntfs.\n\nFor unformatted partitions, cfdisk can be used.\n" ;;
 		esac