btrfs support

Fail to install the ubuntu when the / volume is btrfs
 #24

script/lib/common.sh

@@ -291,8 +291,9 @@ function para_install_msg() {
 function post_install() {
 	## Mount the target file system
 	# ${TARGETMOUNTPOINT} is created by the GUI/TUI installer
+	# ${BTRFSOPTION} is defined by the caller of this function for BTRFS formated volume. 
 	echo "...Mounting /dev/mapper/${VGNAME}-${LVROOTNAME} on ${TARGETMOUNTPOINT}."
-	mount /dev/mapper/"${VGNAME}"-"${LVROOTNAME}" "${TARGETMOUNTPOINT}"
+	mount "${BTRFSOPTION}" /dev/mapper/"${VGNAME}"-"${LVROOTNAME}" "${TARGETMOUNTPOINT}"
 
 	# And mount other directories
 	echo "...Mounting all other dirs."

script/ubuntu-kaiten-yaki.sh

@@ -53,6 +53,15 @@ function main() {
 	#                                Post-install stage 
 	# ******************************************************************************* 
 
+	# If the target volume is formated by btrfs, Ubiquity install the root into the
+	# @ sub-volume. Thus, mount command inside post_install have to use special option
+	# to specify @ as mount target. 
+	if lsblk -o NAME,FSTYPE | grep -i "${VGNAME}-${LVROOTNAME}" | grep -i "btrfs" > /dev/null ; then 
+		export BTRFSOPTION="-o subvol=@"
+	else
+		export BTRFSOPTION=""
+	fi
+
 	# Distribution dependent finalizing. Embedd encryption key into the ramfs image.
 	# The script is parameterized by env-variable to fit to the distribution 
 	post_install

script/void-kaiten-yaki.sh

@@ -74,6 +74,9 @@ function main() {
 	#                                Post-install stage 
 	# ******************************************************************************* 
 
+	# We don't need special option for BTRFSOPTION. 
+	export BTRFSOPTION=""
+
 	# Distribution dependent finalizing. Embedd encryption key into the ramfs image. 
 	# The script is parameterized by env-variable to fit to the distribution 
 	post_install