btrfs-mount-repair

#!/bin/sh

# Jolla btrfs repair and mount script
#
# Copyright (C) 2014 Jolla Ltd.
# Contact: Kalle Jokiniemi <kalle.jokiniemi@jolla.com>
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation; version 2
# of the License.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.

print_help() {
    echo "Usage: $0 <device> <mount-directory>"
    echo "       device          - btrfs device to be repaired and mounted"
    echo "       mount-directory - where to mount the device"
    echo "NOTE:  If repair is succesful, device will be left mounted in"
    echo "       mount-directory"
}

if [ -z $1 ] || [ ! -e $1 ]; then
    echo "$0: Invalid device: \"$1\"" > /dev/kmsg
    print_help
    exit 1
else
    ROOTDEV=$1
fi

if [ -z $2 ] || [ ! -e $2 ]; then
    echo "$0: Invalid mount-directory: \"$2\"" > /dev/kmsg
    print_help
    exit 1
else
    TARGET=$2
fi

# First try simple clearing of the free space cache
if mount -t btrfs -o recovery,nospace_cache,clear_cache,autodefrag $ROOTDEV $TARGET; then
    echo "$0: Root mounted with recovery options"  > /dev/kmsg
    exit 0
fi
# in case FS got mounted as read-only..
umount $TARGET

# Try normal btrfs check repair
btrfs check --repair $ROOTDEV
if mount -t btrfs -o recovery,clear_cache,autodefrag $ROOTDEV $TARGET; then
    echo "$0: Root mounted after repair"  > /dev/kmsg
    exit 0
fi
umount $TARGET

# Try rebuilding checksum tree
btrfs check --init-csum-tree $ROOTDEV
if mount -t btrfs -o recovery,clear_cache,autodefrag $ROOTDEV $TARGET; then
    echo "$0: Root mounted after rebuilding btrfs checksum tree"  > /dev/kmsg
    exit 0
fi
umount $TARGET

# Try rebuilding the extent tree, this takes the longest time.
btrfs check --init-extent-tree $ROOTDEV
if mount -t btrfs -o recovery,clear_cache,autodefrag $ROOTDEV $TARGET; then
    echo "$0 Root mounted after rebuilding btrfs extent tree"  > /dev/kmsg
    exit 0
fi

echo "$0: Failed to repair and mount $ROOTDEV" > /dev/kmsg
exit 1