defaults/linuxrc: Try to determine filesystem type

'mount -t auto' will not trigger module loading for filesystem kernel modules.
Therefore we try to determine filesystem to trigger module loading in case
filesystem isn't built into the kernel.

Bug: https://bugs.gentoo.org/739250
Signed-off-by: Thomas Deutschmann <whissi@gentoo.org>

2 files changed, 46 insertions, 2 deletions

diff --git a/defaults/initrd.scripts b/defaults/initrd.scripts
index ee7ca2ca..36f47919 100644
--- a/defaults/initrd.scripts
+++ b/defaults/initrd.scripts
@@ -198,6 +198,8 @@ findmediamount() {
 				fi
 				good_msg "Attempting to mount media: ${x}" ${CRYPT_SILENT}
 
+				CDROOT_TYPE=$(determine_fs "${x}" "${CDROOT_TYPE}")
+
 				run mount -t ${CDROOT_TYPE} ${x} ${mntcddir} >/dev/null 2>&1
 				if [ $? -eq 0 ]
 				then
@@ -233,6 +235,31 @@ findmediamount() {
 	[ -n "${result}" ] || bad_msg "Media not found" ${CRYPT_SILENT}
 }
 
+determine_fs() {
+	local _dev="${1}"
+	local _orig="${2:-auto}"
+	local _fs line
+
+	_fs=$(udevadm info --query=env --name="$_dev" 2>/dev/null | \
+		while read line || [ -n "${line}" ]
+		do
+			if str_starts ${line} "ID_FS_TYPE="
+			then
+				echo ${line#ID_FS_TYPE=}
+				break
+			fi
+		done
+	)
+	_fs=${_fs:-auto}
+
+	if [ "${_fs}" = "auto" ]
+	then
+		_fs="${_orig}"
+	fi
+
+	echo "${_fs}"
+}
+
 devicelist() {
 	# Locate the cdrom device with our media on it.
 	# CDROM DEVICES
@@ -697,7 +724,9 @@ setup_aufs() {
 		then
 			good_msg "Mounting ${aufs_dev} to ${aufs_memory} for aufs support"
 
-			if ! run mount -t auto "${aufs_dev}" "${aufs_dev_mnt}" >/dev/null 2>&1
+			local mounttype=$(determine_fs "${aufs_dev}" "auto")
+
+			if ! run mount -t ${mounttype} "${aufs_dev}" "${aufs_dev_mnt}" >/dev/null 2>&1
 			then
 				bad_msg "Mount of ${aufs_dev} failed, falling back to ramdisk based aufs"
 				unset aufs_dev
@@ -2727,6 +2756,17 @@ get_zfs_property() {
 	echo "$(zfs get -H -o value ${propertyname} "${device}" 2>/dev/null)"
 }
 
+# Returns TRUE if $1 contains literal string $2 at the
+# beginning and is not empty
+str_starts() {
+	if [ "${1#"${2}"*}" != "${1}" ]
+	then
+		return 0
+	fi
+
+	return 1
+}
+
 # If the kernel is handed a mount option is does not recognize, it WILL fail to
 # mount. util-linux handles auto/noauto, but busybox passes it straight to the kernel
 # which then rejects the mount.
diff --git a/defaults/linuxrc b/defaults/linuxrc
index b42366ff..061d3e01 100644
--- a/defaults/linuxrc
+++ b/defaults/linuxrc
@@ -910,6 +910,10 @@ do
 			# If $REAL_ROOT is a symlink
 			# Resolve it like util-linux mount does
 			[ -L ${REAL_ROOT} ] && REAL_ROOT=$(readlink -f ${REAL_ROOT})
+
+			# determine fs -- 'auto' will not trigger module loading!
+			ROOTFSTYPE=$(determine_fs "${REAL_ROOT}" "${ROOTFSTYPE}")
+
 			# mount ro so fsck doesn't barf later
 			if [ "${REAL_ROOTFLAGS}" = '' ]
 			then
@@ -1028,7 +1032,7 @@ then
 				MOUNTTYPE="ext2"
 				;;
 			*)
-				MOUNTTYPE="${LOOPTYPE}"
+				MOUNTTYPE=$(determine_fs "/dev/mapper/root" "${MOUNTTYPE}")
 				;;
 		esac
 		run mount -t "${MOUNTTYPE}" -o ro /dev/mapper/root "${NEW_ROOT}/mnt/livecd"