Comment 17 for bug 1441930

Tested on 14.04.3 daily build.

Things go from this:

 ~ # df -h /target
 Filesystem Size Used Available Use% Mounted on
 /dev/mapper/mpath0p2 31.1G 47.9M 29.4G 0% /target

 ~ # cat /proc/swaps
 Filename Type Size Used Priority
 /dev/mapper/mpath0p3 partition 1408448 0 -1

 ~ # dmsetup table | grep ^mpath0
 mpath0: 0 554287104 multipath 1 queue_if_no_path 1 alua 2 1 round-robin 0 1 1 8:0 1000 round-robin 0 1 1 65:144 1000
 mpath0p3: 0 2817024 linear 252:0 66468608
 mpath0p2: 0 66466560 linear 252:0 2048
 mpath0p1: 0 1792 linear 252:0 256

To this:

 ~ # df -h /target
 Filesystem Size Used Available Use% Mounted on
 /dev/mapper/mpath0p2 249.4G 59.1M 236.7G 0% /target

 ~ # cat /proc/swaps
 Filename Type Size Used Priority
 /dev/mapper/mpath0p3 partition 11268032 0 -1

 ~ # dmsetup table | grep ^mpath0
 mpath0-part2: 0 531732480 linear 252:0 16384
 mpath0-part1: 0 14336 linear 252:0 2048
 mpath0: 0 554287104 multipath 1 queue_if_no_path 1 alua 2 1 round-robin 0 1 1 8:0 1000 round-robin 0 1 1 65:144 1000
 mpath0p3: 0 22536192 linear 252:0 531748864
 mpath0p2: 0 531732480 linear 252:0 16384
 mpath0p1: 0 14336 linear 252:0 2048
 mpath0-part3: 0 22536192 linear 252:0 531748864

 (ignore -part and p separators, this is another bug which should be backported for as well)