fix fs-resize would break on 4GB drives, and EEROMS was not properly …

…formatted on USB drives (#921)

* fs-resize: fix disk smaller than 4GiB won't be resized, and part3 of USB drive aren't properly formated
* fs-resize: fix some typo and add disclaimer
* fs-resize: use sector size 512 bytes instead of retriving from device
* fs-resize: reformat the codes to improve readability
* fs-resize: reformat the codes to improve readability, again
* fs-resize: omit EEROMS for 4GB drives, and adjust order of the size figuring logic

packages/sysutils/busybox/scripts/fs-resize

@@ -25,9 +25,11 @@ if [ -e /storage/.please_resize_me ] ; then
   case $PART in
     "/dev/mmcblk"* | "/dev/nvme"*)
       DISK=$(echo $PART | sed s/p2$//g)
+      ROMS_PART_NAME="${DISK}p3"
       ;;
     *)
       DISK=$(echo $PART | sed s/2$//g)
+      ROMS_PART_NAME="${DISK}3"
       ;;
   esac
 
@@ -38,6 +40,23 @@ if [ -e /storage/.please_resize_me ] ; then
   if [ ! -z "$DISK" -a ! -z "$PART" ] ; then
     umount $PART
 
+    DISK_NAME=$(basename $DISK)
+    DISK_SECTORS=$(cat "/sys/block/$DISK_NAME/size") # Obtain the disk sectors count, each sector is always 512 Bytes large, independent of the underlying device, according to https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/include/linux/types.h#n117
+    DISK_SIZE=$(( $DISK_SECTORS * 512 )) # Calculate the disk actual size, in byte
+    if [ $DISK_SIZE -gt 4294967296 ]; then # The optimal behaviour, this will leave 2GiB to storage, and create the EEROMS partition
+      ROMS_CREATE='yes'
+      STORAGE_END='4GiB'
+    elif [ $DISK_SIZE -gt 3221225472 ]; then  # Optionaly omit the EEROMS partition for 4GB cards/drives
+      ROMS_CREATE=''
+      STORAGE_END='100%'
+    else
+      # The bare minumum a EmuELEC image itself needs is 2186280960, but after adding in user configs things become uncontrollable, so we don't care about disks with size between 2085MiB and 3GiB
+      echo 'ERROR: You disk is too small! You need to use a USB drive/SD card that is at least 4GB!'
+      echo 'ERROR: You should NOT try to boot up this drive as it is NOT properly resized!'
+      StartProgress countdown "Powering off in 30s...     " 30 "NOW"
+      poweroff
+    fi
+
     echo "PARTITION RESIZING IN PROGRESS"
     echo ""
     echo "Please do not reboot or turn off your @DISTRONAME@ device!"
@@ -49,55 +68,58 @@ if [ -e /storage/.please_resize_me ] ; then
       StartProgress spinner "Checking layout...      " "sgdisk -e $DISK &>/dev/null"
     fi
 
-# EmueELEC Get EEROMS filetype
-ROM_FS_TYPE="vfat"
-PARTED_FS_TYPE="fat32"
+    # EmueELEC Get EEROMS filetype
+    ROM_FS_TYPE="vfat"
+    PARTED_FS_TYPE="fat32"
 
-if [ -e "/flash/ee_fstype" ]; then
-    EE_FS_TYPE=$(cat "/flash/ee_fstype")
-
-    case $EE_FS_TYPE in
-    "ntfs")
-        ROM_FS_TYPE="ntfs"
-        PARTED_FS_TYPE="ntfs"
-    ;;
-    "ext4")
-        ROM_FS_TYPE="ext4"
-        PARTED_FS_TYPE="ext4"
-    ;;
-    "exfat")
-        ROM_FS_TYPE="exfat"
-        PARTED_FS_TYPE="ntfs"
-    ;;
-    *)
-        # Failsafe
-        ROM_FS_TYPE="vfat"
-        PARTED_FS_TYPE="fat32"
-    ;;
-    esac    
-
-fi 
-    StartProgress spinner "Resizing partition...   " "parted -s -a optimal -m $DISK resizepart 2 4GiB &>/dev/null"
+    if [ -e "/flash/ee_fstype" ]; then
+      EE_FS_TYPE=$(cat "/flash/ee_fstype")
+
+      case $EE_FS_TYPE in
+      "ntfs")
+          ROM_FS_TYPE="ntfs"
+          PARTED_FS_TYPE="ntfs"
+      ;;
+      "ext4")
+          ROM_FS_TYPE="ext4"
+          PARTED_FS_TYPE="ext4"
+      ;;
+      "exfat")
+          ROM_FS_TYPE="exfat"
+          PARTED_FS_TYPE="ntfs"
+      ;;
+      *)
+          # Failsafe
+          ROM_FS_TYPE="vfat"
+          PARTED_FS_TYPE="fat32"
+      ;;
+      esac    
+
+    fi
+
+    StartProgress spinner "Resizing partition...   " "parted -s -a optimal -m $DISK resizepart 2 $STORAGE_END &>/dev/null"
     StartProgress spinner "Checking file system... " "e2fsck -f -p $PART &>/dev/null"
     StartProgress spinner "Resizing file system... " "resize2fs $PART &>/dev/null"
-    StartProgress spinner "Creating EEROMS partition..." "parted -s -a optimal -m $DISK mkpart primary ${PARTED_FS_TYPE} 4296MB 100% &>/dev/null"
-    partprobe &>/dev/null
-
-case $ROM_FS_TYPE in 
-    "ntfs")
-    StartProgress spinner "Formatting EEROMS partition as NTFS..." "mkfs.ntfs -L EEROMS -f ${DISK}p3 &>/dev/null"
-    ;;
-    "ext4")
-    StartProgress spinner "Formatting EEROMS partition as EXT4..." "mkfs.ext4 -L EEROMS -t ext4 -O 64bit ${DISK}p3 &>/dev/null"
-    ;;
-    "exfat")
-    StartProgress spinner "Formatting EEROMS partition as EXFAT..." "mkfs.exfat -n EEROMS ${DISK}p3 &>/dev/null"
-    ;;
-    *)
-    StartProgress spinner "Formatting EEROMS partition as FAT32..." "mkfs.vfat -n EEROMS ${DISK}p3 &>/dev/null"
-    ;;
-esac    
-
+    if [ "$ROMS_CREATE" ]; then
+      StartProgress spinner "Creating EEROMS partition..." "parted -s -a optimal -m $DISK mkpart primary ${PARTED_FS_TYPE} 4GiB 100% &>/dev/null"
+      partprobe &>/dev/null
+      case $ROM_FS_TYPE in 
+        "ntfs")
+        StartProgress spinner "Formatting EEROMS partition as NTFS..." "mkfs.ntfs -L EEROMS -f ${ROMS_PART_NAME} &>/dev/null"
+        ;;
+        "ext4")
+        StartProgress spinner "Formatting EEROMS partition as EXT4..." "mkfs.ext4 -L EEROMS -t ext4 -O 64bit ${ROMS_PART_NAME} &>/dev/null"
+        ;;
+        "exfat")
+        StartProgress spinner "Formatting EEROMS partition as EXFAT..." "mkfs.exfat -n EEROMS ${ROMS_PART_NAME} &>/dev/null"
+        ;;
+        *)
+        StartProgress spinner "Formatting EEROMS partition as FAT32..." "mkfs.vfat -n EEROMS ${ROMS_PART_NAME} &>/dev/null"
+        ;;
+      esac   
+    else
+      echo 'WARNING: EEROMS partition is omitted for 4GB drives'
+    fi
     StartProgress countdown "Rebooting in 5s...     " 5 "NOW"
   fi
 fi