tree 69d2f04484c1945ba91af2a12e774606ce0fda07
parent 5576f7cc13bdec1e25ce7573deca0058d7ddb3bb
author Yifan Hong <elsk@google.com> 1566956261 -0700
committer Yifan Hong <elsk@google.com> 1567721674 -0700

libsnapshot: MapPartitionWithSnapshot cleanup itself if failed

When we run MapPartitionWithSnapshot, intermediate devices aren't
cleaned up if the call fails. Hence, record these intermediate devices
we have created along the way using the new AutoDevices class. Upon
failure, the AutoDevices object will be destroyed, and all the
intermediate devices will be deleted from device mapper or image
manager. Upon success, AutoDevices::Release() makes sure the
intermediate devices aren't deleted.

Test: libsnapshot_test

Change-Id: Iff4c1297528288a27765c0224b67254b68c89776