2 # invoked by backup scripts as
3 # lvm snap $vardir $device $mountpoint
4 # creates and mounts on $vardir/snap-mount
5 # creates $vardir/snap-device -> device
17 lvm_lvtools_opts='-A n'
21 test ! -f /etc/chiark-backup/settings.sh || . /etc/chiark-backup/settings.sh
23 case "$nargs.$opmode" in
28 usage: .../lvm snap VARDIR DEV MOUNT
36 #---------- clean up anything
38 snmnt="$vardir/snap-mount"
39 umount -v "$snmnt" || true
40 test ! -d "$snmnt" || rmdir -- "$snmnt"
43 old_lv_dev="$(readlink $vardir/snap-device)"
49 lvchange $lvm_lvtools_opts -a n $old_lv_dev
50 lvremove -f $lvm_lvtools_opts $old_lv_dev
52 rm $vardir/snap-device
55 if test "$opmode" = drop; then
56 echo 'lvm snap dropped'
60 #---------- create snapshot
62 fstype="$(mount | sed -n \
63 "s,^$device on $mountpoint type \([a-z0-9][a-z0-9]*\) .*,-t \1 ,p")"
65 if [ -z "$lvm_lvsize_opts" ]; then
66 df="$(df -P -k $device)"
67 blocks="$(printf "%s" "$df" | sed -n '2,$s,^/dev/[^ ]*[ ][ ]*[0-9][0-9]*[ ][ ]*\([0-9][0-9]*\)[ ].*,\1,p')"
68 lvm_lvsize_opts="-L $blocks"K
71 lvpath="$(dirname "$device")/$lvm_lv"
73 ln -s -- "$lvpath" "$vardir"/snap-device
80 $lvm_lvcreate_opts "$device" $lvm_lvcreate_args
83 mount -v -r $fstype $lvm_mount_opts "$lvpath" "$snmnt"
85 echo 'lvm snap activated'