Add ZRAM ramdisk support

buildroot-external/rootfs-overlay/etc/fstab

@@ -9,4 +9,3 @@ tmpfs		/run		tmpfs	mode=0755,nosuid,nodev	0	0
 sysfs		/sys		sysfs	defaults	0	0
 #tmpfs		/var/log	tmpfs	defaults	0	0
 tmpfs		/var/tmp	tmpfs	defaults	0	0
-tmpfs		/ramdisk	tmpfs	rw,nodev,nosuid,size=20M	0	0

buildroot-external/rootfs-overlay/usr/lib/systemd/system/ramdisk.mount

@@ -0,0 +1,16 @@
+[Unit]
+Description=OVOS ZRAM ramdisk
+DefaultDependencies=no
+Requires=zram-ramdisk.service
+After=zram-ramdisk.service
+Before=umount.target
+Conflicts=umount.target
+
+[Mount]
+What=/dev/zram1
+Where=/ramdisk
+Type=ext4
+Options=nobarrier,strictatime,nosuid,nodev
+
+[Install]
+WantedBy=local-fs.target

buildroot-external/rootfs-overlay/usr/lib/systemd/system/zram-ramdisk.service

@@ -0,0 +1,15 @@
+[Unit]
+Description=OVOS ZRAM ramdisk
+DefaultDependencies=no
+Before=ramdisk.mount
+RefuseManualStart=true
+RefuseManualStop=true
+
+[Service]
+Type=oneshot
+ExecStart=/usr/libexec/ovos-zram -t fs -m ramdisk -s 20M
+RemainAfterExit=true
+StandardOutput=null
+
+[Install]
+WantedBy=ovos-zram.target

buildroot-external/rootfs-overlay/usr/libexec/ovos-zram

@@ -35,7 +35,7 @@ while [ "$1" != "" ]; do
 done
 
 # Valide Type
-if [ "$TYPE" != "swap" ]; then
+if [ "$TYPE" != "swap" ] && [ "$TYPE" != "fs" ]; then
     echo "[Error] Type unknown!"
     exit 1
 fi
@@ -43,8 +43,8 @@ fi
 # Lookup device
 if [ "$TYPE" = "swap" ]; then
     DEVICE="/dev/zram0"
-#elif [ "$MOUNT" = "var" ]; then
-#    DEVICE="/dev/zram1"
+elif [ "$MOUNT" = "ramdisk" ]; then
+    DEVICE="/dev/zram1"
 #elif [ "$MOUNT" = "tmp" ]; then
 #    DEVICE="/dev/zram2"
 else
@@ -64,3 +64,8 @@ zramctl "$DEVICE" -s "$SIZE" -a lz4
 if [ "$TYPE" = "swap" ]; then
     mkswap -L "ovos-zramswap" "$DEVICE"
 fi
+
+# FileSystem
+if [ "$TYPE" = "fs" ]; then
+    mkfs.ext4 -L "ovos-$MOUNT" -O ^has_journal "$DEVICE"
+fi