Issue

• Running Scan Alignment via RHV-M GUI reports failure on VM guest disk's with multiple snapshots.

Engine.log

2017-10-30 10:41:10,801 WARN  [org.ovirt.engine.core.dal.dbbroker.auditloghandling.AuditLogDirector] (org.ovirt.thread.pool-6-thread-38) [5ae50f9f] Correlation ID: 5ae50f9f, Job ID: 64366993-b4ef-4f5c-a0ce-e412cb6260a2, Call Stack: null, Custom Event ID: -1, Message: Alignment scan of disk 'rhev_guest_disk1' failed

vdsm.log

2017-10-30 11:25:29,921+0100 ERROR (jsonrpc/2) [jsonrpc.JsonRpcServer] Internal server error (__init__:570)
Traceback (most recent call last):
  File "/usr/lib/python2.7/site-packages/yajsonrpc/__init__.py", line 565, in _handle_request
    res = method(**params)
  File "/usr/lib/python2.7/site-packages/vdsm/rpc/Bridge.py", line 202, in _dynamicMethod
    result = fn(*methodArgs)
  File "/usr/share/vdsm/API.py", line 832, in getDiskAlignment
    return self._cif.getDiskAlignment(disk)
  File "/usr/share/vdsm/clientIF.py", line 422, in getDiskAlignment
    out = alignmentScan.scanImage(volPath)
  File "/usr/share/vdsm/alignmentScan.py", line 60, in scanImage
    "or guest:\n%s" % err)
VirtAlignError: An error scanning the disk image or guest:
['libguestfs: error: qemu-img: /tmp/libguestfsGv53EW/overlay1: qemu-img exited with error status 1.', 'To see full error messages you may need to enable debugging.', 'Do:', '  export LIBGUESTFS_DEBUG=1 LIBGUESTFS_TRACE=1', 'and run the command again.  For further information, read:', '  http://libguestfs.org/guestfs-faq.1.html#debugging-libguestfs', "You can also run 'libguestfs-test-tool' and post the *complete* output", 'into a bug report or message to the libguestfs mailing list.']
2017-10-30 11:25:29,922+0100 INFO  (jsonrpc/2) [jsonrpc.JsonRpcServer] RPC call VM.getDiskAlignment failed (error -32603) in 0.92 seconds (__init__:533)