aw-overlay/app-backup/urbackup-client/files/dattobd_create_filesystem_snapshot

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#!/bin/sh
set -e
mkdir -p /mnt/urbackup_snaps
SNAP_ID=$1
SNAP_MOUNTPOINT="$2"
SNAP_DEST=/mnt/urbackup_snaps/$SNAP_ID
DEVICE=$(df -T -P | egrep " ${SNAP_MOUNTPOINT}\$" | head -n 1 | tr -s " " | cut -d" " -f1)
TYPE=$(df -T -P | egrep " ${SNAP_MOUNTPOINT}\$" | head -n 1 | tr -s " " | cut -d" " -f2)
if [ "x$DEVICE" = "x" ]
then
echo "Cannot get device for filesystem $SNAP_MOUNTPOINT"
exit 1
fi
echo "Snapshotting device $DEVICE via dattobd..."
NUM=0
while [ -e "/dev/datto$NUM" ]
do
NUM=`expr $NUM + 1`
done
if ! modprobe dattobd
then
echo "Dattobd kernel module not available"
exit 1
fi
echo "Using /dev/datto$NUM..."
sync
dbdctl setup-snapshot "$DEVICE" "$SNAP_MOUNTPOINT/.datto_$SNAP_ID" $NUM
echo $NUM > ${SNAP_DEST}-num
DEV_SIZE=`blockdev --getsize /dev/datto$NUM`
truncate -s100M $SNAP_MOUNTPOINT/.overlay_$SNAP_ID
LODEV=`losetup -f`
if [ "x$LODEV" = x ]
then
rm "${SNAP_DEST}-num"
rm $SNAP_MOUNTPOINT/.overlay_$SNAP_ID
dbdctl destroy $NUM
exit 1
fi
losetup $LODEV $SNAP_MOUNTPOINT/.overlay_$SNAP_ID
echo "0 $DEV_SIZE snapshot /dev/datto$NUM $LODEV N 8" | dmsetup create "wsnap-$SNAP_ID"
echo "Mounting /dev/mapper/wsnap-$SNAP_ID..."
mkdir -p $SNAP_DEST
MOUNTOPTS="ro"
if [ $TYPE = "xfs" ]
then
MOUNTOPTS="ro,nouuid"
fi
if ! mount -o $MOUNTOPTS /dev/mapper/wsnap-$SNAP_ID $SNAP_DEST
then
echo "Mounting filesystem failed"
rmdir "$SNAP_DEST"
rm "${SNAP_DEST}-num"
dmsetup remove "wsnap-$SNAP_ID"
losetup -d $LODEV
rm $SNAP_MOUNTPOINT/.overlay_$SNAP_ID
dbdctl destroy $NUM
exit 1
fi
echo "SNAPSHOT=$SNAP_DEST"
exit 0