13 [ -n "$cowlink" ] && rm $cowlink
14 [ -n "$dmname" ] && dmsetup remove $dmname
15 [ -n "$tmploop" ] && losetup -d $tmploop
16 [ -n "$tmpfile" ] && rm $tmpfile
17 [ -n "$imgloop" ] && losetup -d $imgloop
24 if [ -z "$imgfile" -o -z "$command" ] ; then
25 echo Syntax: $0 /path/to/image/file command [args..]
29 # Set up image loop device
30 x=`losetup -f` ; losetup -r $x $imgfile ; imgloop=$x
32 # Create temporary file and set up temporary loop device
33 tmpfile=`mktemp $imgfile.XXXXXXXXXX`
34 truncate -r $imgfile $tmpfile
35 x=`losetup -f` ; losetup $x $tmpfile ; tmploop=$x
37 # Create snapshot device
38 imgsize=`blockdev --getsz $imgloop`
39 x=`basename $imgfile` ; echo 0 $imgsize snapshot $imgloop $tmploop N 16 | \
40 dmsetup create $x ; dmname=$x
41 chown --reference=$imgfile /dev/mapper/$dmname
42 chmod --reference=$imgfile /dev/mapper/$dmname
45 x=$imgfile.cow ; ln -s /dev/mapper/$dmname $x ; cowlink=$x
48 echo "Created $cowlink"
49 $command "$@" $cowlink