From 0eb02adc27344e3ae1243e728ad30aa9a2529028 Mon Sep 17 00:00:00 2001
From: Joey Hess <joeyh@debian.org>
Date: Wed, 27 Jan 2010 20:14:29 +0000
Subject: [PATCH] initial commit of partman-btrfs

This is untested and unlikely to work without parted support.
Committing what I have since I don't trust btrfs to preserve the data. ;-)

Note to translators: Probably not worth wasting your time with this yet.
Have not run debconf-updatepo.

r62090
---
 TODO                             | 10 ++++
 active_partition/_numbers        |  1 +
 active_partition/btrfs/choices   | 70 +++++++++++++++++++++++++++
 active_partition/btrfs/do_option | 41 ++++++++++++++++
 check.d/_numbers                 |  2 +
 check.d/no_btrfs_boot            | 32 +++++++++++++
 check.d/nomountpoint_btrfs       | 37 +++++++++++++++
 commit.d/_numbers                |  1 +
 commit.d/format_btrfs            | 81 ++++++++++++++++++++++++++++++++
 debian/changelog                 |  6 +++
 debian/compat                    |  1 +
 debian/control                   | 14 ++++++
 debian/copyright                 |  4 ++
 debian/di-numbers                |  7 +++
 debian/install                   |  3 ++
 debian/partman-btrfs.templates   | 73 ++++++++++++++++++++++++++++
 debian/rules                     |  3 ++
 finish.d/_numbers                |  1 +
 finish.d/aptinstall_btrfs        | 27 +++++++++++
 fstab.d/btrfs                    | 39 +++++++++++++++
 init.d/_numbers                  |  1 +
 init.d/kernelmodules_btrfs       | 20 ++++++++
 mount.d/_numbers                 |  1 +
 mount.d/btrfs                    | 20 ++++++++
 mountoptions/btrfs               | 17 +++++++
 parted_names/btrfs               |  1 +
 valid_filesystems/_numbers       |  1 +
 valid_filesystems/btrfs          | 25 ++++++++++
 28 files changed, 539 insertions(+)
 create mode 100644 TODO
 create mode 100644 active_partition/_numbers
 create mode 100755 active_partition/btrfs/choices
 create mode 100755 active_partition/btrfs/do_option
 create mode 100644 check.d/_numbers
 create mode 100755 check.d/no_btrfs_boot
 create mode 100755 check.d/nomountpoint_btrfs
 create mode 100644 commit.d/_numbers
 create mode 100755 commit.d/format_btrfs
 create mode 100644 debian/changelog
 create mode 100644 debian/compat
 create mode 100644 debian/control
 create mode 100644 debian/copyright
 create mode 100644 debian/di-numbers
 create mode 100644 debian/install
 create mode 100644 debian/partman-btrfs.templates
 create mode 100755 debian/rules
 create mode 100644 finish.d/_numbers
 create mode 100755 finish.d/aptinstall_btrfs
 create mode 100755 fstab.d/btrfs
 create mode 100644 init.d/_numbers
 create mode 100755 init.d/kernelmodules_btrfs
 create mode 100644 mount.d/_numbers
 create mode 100755 mount.d/btrfs
 create mode 100644 mountoptions/btrfs
 create mode 100644 parted_names/btrfs
 create mode 100644 valid_filesystems/_numbers
 create mode 100755 valid_filesystems/btrfs

diff --git a/TODO b/TODO
new file mode 100644
index 0000000..8c95a65
--- /dev/null
+++ b/TODO
@@ -0,0 +1,10 @@
+* Support for multi-volume btrfs filesystems
+* Support for other mkfs.btrfs options, if any are useful.
+* Support for btrfs snapshots / using existing btrfs?
+* Check if errors=remount-ro makes sense to use.
+* mountoptions is missing a few options that may be worth supporting,
+  including degraded, and all optionds that require a parameter.
+* mountoptions contains nobarrier, which is an unsafe option. Remove? Warn?
+* parted support needed for filesystem detection #567176
+* Resizing?
+* Allow forcing use of btrfs for /boot (would probably work with eg, lilo)
diff --git a/active_partition/_numbers b/active_partition/_numbers
new file mode 100644
index 0000000..6ff6666
--- /dev/null
+++ b/active_partition/_numbers
@@ -0,0 +1 @@
+45 btrfs
diff --git a/active_partition/btrfs/choices b/active_partition/btrfs/choices
new file mode 100755
index 0000000..262746a
--- /dev/null
+++ b/active_partition/btrfs/choices
@@ -0,0 +1,70 @@
+#!/bin/sh
+
+. /usr/share/debconf/confmodule
+
+set -e
+
+dev=$1
+id=$2
+part=$dev/$id
+
+cd $dev
+
+[ -f $part/method -a -f $part/acting_filesystem ] || exit 0
+
+filesystem=$(cat $part/acting_filesystem)
+
+case "$filesystem" in
+    btrfs)
+	:
+	;;
+    *)
+	exit 0
+	;;
+esac
+
+choice_mountpoint () {
+	case "$filesystem" in
+	    btrfs)
+		if [ -f $part/mountpoint ]; then
+			mp=$(cat $part/mountpoint)
+		else
+			db_metaget partman-basicfilesystems/text/no_mountpoint description
+			mp="$RET"
+		fi
+		db_metaget partman-btrfs/text/specify_mountpoint description
+		printf "mountpoint\t%s\${!TAB}%s\n" "$RET" "$mp"
+		;;
+	esac
+}
+
+choice_options () {
+	db_metaget partman-basicfilesystems/text/options description
+	printf "options\t%s\${!TAB}%.45s\n" "$RET" "$(get_mountoptions $dev $id)"
+}
+
+choice_label () {
+	# allow to set label only if the partition is to be formatted
+	[ -f $part/format ] || return 0
+	[ ! -f $part/formatted \
+	  -o $part/formatted -ot $part/method \
+	  -o $part/formatted -ot $part/filesystem ] || return 0
+	case "$filesystem" in
+	    btrfs)
+		if [ -f $part/label ]; then
+			label=$(cat $part/label)
+		else
+			db_metaget partman-basicfilesystems/text/none description
+			label=$RET
+		fi
+		db_metaget partman-basicfilesystems/text/specify_label description
+		printf "label\t%s\${!TAB}%s\n" "$RET" "$label"
+		;;
+	esac
+}
+
+choice_mountpoint
+
+choice_options
+
+choice_label
diff --git a/active_partition/btrfs/do_option b/active_partition/btrfs/do_option
new file mode 100755
index 0000000..a4c6ae4
--- /dev/null
+++ b/active_partition/btrfs/do_option
@@ -0,0 +1,41 @@
+#!/bin/sh
+
+. /lib/partman/lib/base.sh
+
+dev=$2
+id=$3
+part=$dev/$id
+
+cd $dev
+
+[ -f $part/method -a -f $part/acting_filesystem ] || return 0
+filesystem=$(cat $part/acting_filesystem)
+
+case $1 in
+    mountpoint)
+	if select_mountpoint $dev $id; then
+		update_partition $dev $id
+	fi
+	;;
+    options)
+	select_mountoptions $dev $id
+	;;
+    label)
+	label=''
+	if [ -f $part/label ]; then
+		label=$(cat $part/label)
+	fi
+	db_set partman-basicfilesystems/choose_label "$label"
+	db_input critical partman-basicfilesystems/choose_label || true
+	db_go || exit 1
+	db_get partman-basicfilesystems/choose_label
+	if [ "$RET" ]; then
+		echo "$RET" >$part/label
+	else
+		rm -f $part/label
+	fi
+	db_reset partman-basicfilesystems/choose_label
+	;;
+esac
+
+exit 0
diff --git a/check.d/_numbers b/check.d/_numbers
new file mode 100644
index 0000000..710d9fa
--- /dev/null
+++ b/check.d/_numbers
@@ -0,0 +1,2 @@
+09 nomountpoint_btrfs
+05 no_btrfs_boot
diff --git a/check.d/no_btrfs_boot b/check.d/no_btrfs_boot
new file mode 100755
index 0000000..ef9c180
--- /dev/null
+++ b/check.d/no_btrfs_boot
@@ -0,0 +1,32 @@
+#!/bin/sh
+# grub and other bootloaders that read the filesystem do not support /boot
+# on btrfs. (lilo should work). Detect and warn.
+
+. /lib/partman/lib/base.sh
+
+get_btrfs_root_boot () {
+	(for i in /lib/partman/fstab.d/*; do
+		[ -x "$i" ] || continue
+		$i
+	done) |
+	while read fs mp type options dump pass; do
+		if [ "$mp" = / ]; then
+			echo root_type=$type
+		elif [ "$mp" = /boot ]; then
+			echo boot_type=$type
+		fi
+	done
+}
+eval "$(get_btrfs_root_boot)"
+
+if [ "$boot_type" = btrfs ]; then
+	db_input critical partman-btrfs/btrfs_boot || true
+	db_go || exit 1
+	exit 1
+fi
+
+if [ "$boot_type" = "" ] && [ "$root_type" = btrfs ]; then
+	db_input critical partman-btrfs/btrfs_root || true
+	db_go || exit 1
+	exit 1
+fi
diff --git a/check.d/nomountpoint_btrfs b/check.d/nomountpoint_btrfs
new file mode 100755
index 0000000..f6ce818
--- /dev/null
+++ b/check.d/nomountpoint_btrfs
@@ -0,0 +1,37 @@
+#!/bin/sh
+
+. /lib/partman/lib/base.sh
+
+for dev in $DEVICES/*; do
+	[ -d "$dev" ] || continue
+	cd $dev
+	partitions=
+	open_dialog PARTITIONS
+	while { read_line num id size type fs path name; [ "$id" ]; }; do
+		[ "$fs" != free ] || continue
+		partitions="$partitions $id,$num"
+	done
+	close_dialog
+
+	for part in $partitions; do
+		id=${part%,*}
+		num=${part#*,}
+		[ -f $id/method ] || continue
+		[ -f $id/acting_filesystem ] || continue
+		filesystem=$(cat $id/acting_filesystem)
+		case "$filesystem" in
+		    btrfs)
+			[ ! -f "$id/mountpoint" ] || continue
+			db_subst partman-btrfs/no_mount_point PARTITION "$num"
+			db_subst partman-btrfs/no_mount_point FILESYSTEM "$filesystem"
+			db_subst partman-btrfs/no_mount_point DEVICE $(humandev $(cat device))
+			db_input critical partman-btrfs/no_mount_point || true
+			db_go || exit 1
+			db_get partman-btrfs/no_mount_point
+			if [ "$RET" = true ]; then
+				exit 1
+			fi
+			;;
+		esac
+	done
+done
diff --git a/commit.d/_numbers b/commit.d/_numbers
new file mode 100644
index 0000000..6fbce3c
--- /dev/null
+++ b/commit.d/_numbers
@@ -0,0 +1 @@
+50 format_btrfs
diff --git a/commit.d/format_btrfs b/commit.d/format_btrfs
new file mode 100755
index 0000000..a402fdf
--- /dev/null
+++ b/commit.d/format_btrfs
@@ -0,0 +1,81 @@
+#!/bin/sh
+
+. /lib/partman/lib/base.sh
+
+enable_swap
+
+for dev in $DEVICES/*; do
+	[ -d "$dev" ] || continue
+	cd $dev
+	partitions=
+	open_dialog PARTITIONS
+	while { read_line num id size type fs path name; [ "$id" ]; }; do
+		[ "$fs" != free ] || continue
+		partitions="$partitions $id,$num"
+	done
+	close_dialog
+
+	for part in $partitions; do
+		id=${part%,*}
+		num=${part#*,}
+		[ -f $id/method -a -f $id/format \
+		  -a -f $id/acting_filesystem ] || continue
+		filesystem=$(cat $id/acting_filesystem)
+		case $filesystem in
+		    btrfs)
+			if [ -f $id/formatted ] && \
+			   [ $id/formatted -nt $id/method ] && \
+			   ([ ! -f $id/filesystem ] || \
+			    [ $id/formatted -nt $id/filesystem ]); then
+				continue
+			fi
+			log "Try to create file system for $dev/$id"
+			if [ -f $id/mountpoint ]; then
+				template=partman-basicfilesystems/progress_formatting_mountable
+				db_subst $template MOUNT_POINT "$(cat $id/mountpoint)"
+			else
+				template=partman-basicfilesystems/progress_formatting
+			fi
+			open_dialog PARTITION_INFO $id
+			read_line x1 x2 x3 x4 x5 device x6
+			close_dialog
+
+			RET=''
+			db_metaget  partman/filesystem_short/"$filesystem" description || RET=''
+			[ "$RET" ] || RET="$filesystem"
+			db_subst $template TYPE "$RET"
+			db_subst $template PARTITION "$num"
+			db_subst $template DEVICE $(humandev $(cat device))
+
+			db_progress START 0 3 partman/text/formatting
+			db_progress INFO $template
+			db_progress SET 1
+
+			label=''
+			if [ -f $id/label ]; then
+				label=$(cat $id/label | \
+					sed 's/\(............\).*/\1/g')
+			fi
+			code=0
+			# Ensure label is quoted correctly
+			log-output -t partman --pass-stdout \
+				mkfs.btrfs ${label:+-L "$label"} \
+					 $device >/dev/null || code=$?
+			sync
+			db_progress STOP
+
+			if [ "$code" != 0 ]; then
+				db_subst partman-btrfs/create_failed PARTITION "$num"
+				db_subst partman-btrfs/create_failed DEVICE $(humandev $(cat device))
+				db_input critical partman-btrfs/create_failed || true
+				db_go || true
+				#disable_swap
+				exit 1
+			fi
+			>$id/formatted
+			;;
+		esac
+	done
+done
+
+#disable_swap
diff --git a/debian/changelog b/debian/changelog
new file mode 100644
index 0000000..d131f28
--- /dev/null
+++ b/debian/changelog
@@ -0,0 +1,6 @@
+partman-btrfs (1) UNRELEASED; urgency=low
+
+  * Took partman-xfs and s/xfs/btrfs/, essentially.
+  * Added error messages if /boot is on btrfs.
+
+ -- Joey Hess <joeyh@debian.org>  Thu,  4 Mar 2004 12:42:40 -0500
diff --git a/debian/compat b/debian/compat
new file mode 100644
index 0000000..7f8f011
--- /dev/null
+++ b/debian/compat
@@ -0,0 +1 @@
+7
diff --git a/debian/control b/debian/control
new file mode 100644
index 0000000..9714b7f
--- /dev/null
+++ b/debian/control
@@ -0,0 +1,14 @@
+Source: partman-btrfs
+Section: debian-installer
+Priority: standard
+Maintainer: Debian Install System Team <debian-boot@lists.debian.org>
+Uploaders: Anton Zinoviev <zinoviev@debian.org>, Joey Hess <joeyh@debian.org>
+Build-Depends: debhelper (>= 7.0.8), dh-di, po-debconf (>= 0.5.0)
+Vcs-Svn: svn://svn.debian.org/d-i/trunk/packages/partman/partman-btrfs
+
+Package: partman-btrfs
+XC-Package-Type: udeb
+Architecture: all
+Depends: ${misc:Depends}, btrfs-tools-udeb, btrfs-modules, partman-basicfilesystems (>= 59), partman-base (>= 124)
+Provides: partman-filesystem
+Description: Add to partman support for btrfs
diff --git a/debian/copyright b/debian/copyright
new file mode 100644
index 0000000..4740f09
--- /dev/null
+++ b/debian/copyright
@@ -0,0 +1,4 @@
+This package is under the GNU GPL version 2, or any later
+version at your option.
+On Debian system, the GPL is available in 
+/usr/share/common-licenses/GPL-2
diff --git a/debian/di-numbers b/debian/di-numbers
new file mode 100644
index 0000000..3f4a990
--- /dev/null
+++ b/debian/di-numbers
@@ -0,0 +1,7 @@
+active_partition lib/partman
+valid_filesystems lib/partman
+init.d lib/partman
+check.d lib/partman
+commit.d lib/partman
+finish.d lib/partman
+mount.d lib/partman
diff --git a/debian/install b/debian/install
new file mode 100644
index 0000000..2ab08be
--- /dev/null
+++ b/debian/install
@@ -0,0 +1,3 @@
+mountoptions lib/partman
+fstab.d lib/partman
+parted_names lib/partman
diff --git a/debian/partman-btrfs.templates b/debian/partman-btrfs.templates
new file mode 100644
index 0000000..12c76c2
--- /dev/null
+++ b/debian/partman-btrfs.templates
@@ -0,0 +1,73 @@
+Template: partman-btrfs/progress_checking
+Type: text
+# :sl2:
+_Description: Checking the btrfs file system in partition #${PARTITION} of ${DEVICE}...
+
+Template: partman-btrfs/check_failed
+Type: boolean
+# :sl2:
+_Description: Go back to the menu and correct errors?
+ The test of the file system with type btrfs in partition #${PARTITION}
+ of ${DEVICE} found uncorrected errors.
+ .
+ If you do not go back to the partitioning menu and correct these errors,
+ the partition will not be used at all.
+
+Template: partman-btrfs/create_failed
+Type: error
+# :sl2:
+_Description: Failed to create a file system
+ The btrfs file system creation in partition
+ #${PARTITION} of ${DEVICE} failed.
+
+Template: partman-btrfs/no_mount_point
+Type: boolean
+# :sl2:
+_Description: Do you want to return to the partitioning menu?
+ No mount point is assigned for the btrfs file system in partition
+ #${PARTITION} of ${DEVICE}.
+ .
+ If you do not go back to the partitioning menu and assign a mount point
+ from there, this partition will not be used at all.
+
+Template: partman-btrfs/text/specify_mountpoint
+Type: text
+# :sl2:
+# This is an item in the menu "Partition settings"
+_Description: Mount point:
+
+Template: partman-btrfs/text/btrfs
+Type: text
+# :sl2:
+# File system name (untranslatable in many languages)
+_Description: btrfs
+
+Template: partman/filesystem_long/btrfs
+Type: text
+# :sl2:
+# File system name
+_Description: btrfs journaling file system
+
+Template: partman/filesystem_short/btrfs
+Type: text
+# :sl1:
+# Short file system name (untranslatable in many languages)
+_Description: btrfs
+
+Template: partman-btrfs/btrfs_root
+Type: error
+# :sl2:
+_Description: btrfs root file system not supported without separate /boot
+ Your root file system is a btrfs file system. This is not supported
+ by the boot loader used by default by this installer.
+ .
+ You should use a small /boot partition with another file system, such as ext3.
+
+Template: partman-btrfs/btrfs_boot
+Type: error
+# :sl2:
+_Description: btrfs file system not supported for /boot
+ You have mounted a btrfs file system as /boot. This is not supported
+ by the boot loader used by default by this installer.
+ .
+ You should use another file system, such as ext3, for the /boot partition.
diff --git a/debian/rules b/debian/rules
new file mode 100755
index 0000000..37850fb
--- /dev/null
+++ b/debian/rules
@@ -0,0 +1,3 @@
+#! /usr/bin/make -f
+%:
+	dh --with d-i $@
diff --git a/finish.d/_numbers b/finish.d/_numbers
new file mode 100644
index 0000000..c33c079
--- /dev/null
+++ b/finish.d/_numbers
@@ -0,0 +1 @@
+70 aptinstall_btrfs
diff --git a/finish.d/aptinstall_btrfs b/finish.d/aptinstall_btrfs
new file mode 100755
index 0000000..ae79b17
--- /dev/null
+++ b/finish.d/aptinstall_btrfs
@@ -0,0 +1,27 @@
+#!/bin/sh
+
+. /lib/partman/lib/base.sh
+
+btrfs=no
+
+for dev in $DEVICES/*; do
+	[ -d "$dev" ] || continue
+	cd $dev
+	partitions=
+	open_dialog PARTITIONS
+	while { read_line num id size type fs path name; [ "$id" ]; }; do
+		[ "$fs" != free ] || continue
+		[ -f $id/method -a -f $id/acting_filesystem ] || continue
+		filesystem=$(cat $id/acting_filesystem)
+		case $filesystem in
+		    btrfs)
+			btrfs=yes
+			;;
+		esac
+	done
+	close_dialog
+done
+
+if [ "$btrfs" = yes ]; then
+	apt-install btrfs-tools || true
+fi
diff --git a/fstab.d/btrfs b/fstab.d/btrfs
new file mode 100755
index 0000000..9111d3b
--- /dev/null
+++ b/fstab.d/btrfs
@@ -0,0 +1,39 @@
+#!/bin/sh
+
+. /lib/partman/lib/base.sh
+
+for dev in $DEVICES/*; do
+	[ -d $dev ] || continue
+	cd $dev
+	open_dialog PARTITIONS
+	while { read_line num id size type fs path name; [ "$id" ]; }; do
+		[ $fs != free ] || continue
+		[ -f "$id/method" ] || continue
+		[ -f "$id/acting_filesystem" ] || continue
+		method=$(cat $id/method)
+		filesystem=$(cat $id/acting_filesystem)
+		case "$filesystem" in
+		    btrfs)
+			[ -f "$id/mountpoint" ] || continue
+			mountpoint=$(cat $id/mountpoint)
+			# due to #249322, #255135, #258117:
+			if [ "$mountpoint" = /tmp ]; then
+				rm -f $id/options/noexec
+			fi
+			options=$(get_mountoptions $dev $id)
+			if [ "$mountpoint" = / ]; then
+				if [ "$options" = defaults ]; then
+					options="errors=remount-ro"
+				else
+					options="${options},errors=remount-ro"
+				fi
+				pass=1
+			else
+				pass=2
+			fi
+			echo "$path" "$mountpoint" btrfs $options 0 $pass
+			;;
+		esac
+	done
+	close_dialog
+done
diff --git a/init.d/_numbers b/init.d/_numbers
new file mode 100644
index 0000000..5dfb757
--- /dev/null
+++ b/init.d/_numbers
@@ -0,0 +1 @@
+03 kernelmodules_btrfs
diff --git a/init.d/kernelmodules_btrfs b/init.d/kernelmodules_btrfs
new file mode 100755
index 0000000..79a8244
--- /dev/null
+++ b/init.d/kernelmodules_btrfs
@@ -0,0 +1,20 @@
+#!/bin/sh
+
+mkdir -p /var/lib/partman
+
+cat /proc/modules |
+while read module_name x; do
+	if [ "$module_name" = btrfs ]; then
+		>/var/lib/partman/btrfs
+		exit 0
+	fi
+done
+
+if modprobe btrfs >/dev/null 2>/dev/null; then
+	>/var/lib/partman/btrfs
+	exit 0
+fi
+
+if grep -q btrfs /proc/filesystems; then
+	>/var/lib/partman/btrfs
+fi
diff --git a/mount.d/_numbers b/mount.d/_numbers
new file mode 100644
index 0000000..600e6d3
--- /dev/null
+++ b/mount.d/_numbers
@@ -0,0 +1 @@
+70 btrfs
diff --git a/mount.d/btrfs b/mount.d/btrfs
new file mode 100755
index 0000000..eb4b1fb
--- /dev/null
+++ b/mount.d/btrfs
@@ -0,0 +1,20 @@
+#!/bin/sh
+
+set -- $1
+
+fs=$1
+mp=$2
+type=$3
+options=$4
+dump=$5
+pass=$6
+
+case $type in
+    btrfs)
+	mount -t btrfs ${options:+-o "$options"} $fs /target$mp || exit 1
+	echo "umount /target$mp"
+	exit 0
+	;;
+esac
+
+exit 1
diff --git a/mountoptions/btrfs b/mountoptions/btrfs
new file mode 100644
index 0000000..01a5de8
--- /dev/null
+++ b/mountoptions/btrfs
@@ -0,0 +1,17 @@
+noatime
+relatime
+nodev
+nosuid
+noexec
+ro
+sync
+usrquota
+grpquota
+nodatasum
+nodatacow
+nobarrier
+compress
+ssd
+noacl
+notreelog
+flushoncommit
diff --git a/parted_names/btrfs b/parted_names/btrfs
new file mode 100644
index 0000000..00531f6
--- /dev/null
+++ b/parted_names/btrfs
@@ -0,0 +1 @@
+btrfs
diff --git a/valid_filesystems/_numbers b/valid_filesystems/_numbers
new file mode 100644
index 0000000..058feff
--- /dev/null
+++ b/valid_filesystems/_numbers
@@ -0,0 +1 @@
+25 btrfs
diff --git a/valid_filesystems/btrfs b/valid_filesystems/btrfs
new file mode 100755
index 0000000..a92f933
--- /dev/null
+++ b/valid_filesystems/btrfs
@@ -0,0 +1,25 @@
+#!/bin/sh
+
+dev=$1
+id=$2
+property=$3
+
+[ -f /var/lib/partman/btrfs ] || exit 0
+
+case $property in
+    formatable)
+	echo btrfs
+	;;
+    existing)
+	[ -f $id/detected_filesystem ] || exit 0
+	fs=$(cat $id/detected_filesystem)
+
+	case "$fs" in
+	    btrfs)
+		echo btrfs
+		;;
+	esac
+	;;
+esac
+
+