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# Copyright 2013 Cloudbase Solutions Srl
# All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License. You may obtain
# a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.
"""
Utility class for VHD related operations.
Based on the "root/virtualization/v2" namespace available starting with
Hyper-V Server / Windows Server 2012.
"""
import struct
import sys
if sys.platform == 'win32':
import wmi
from xml.etree import ElementTree
from nova.i18n import _
from nova.openstack.common import units
from nova.virt.hyperv import constants
from nova.virt.hyperv import vhdutils
from nova.virt.hyperv import vmutils
from nova.virt.hyperv import vmutilsv2
VHDX_BAT_ENTRY_SIZE = 8
VHDX_HEADER_OFFSETS = [64 * units.Ki, 128 * units.Ki]
VHDX_HEADER_SECTION_SIZE = units.Mi
VHDX_LOG_LENGTH_OFFSET = 68
VHDX_METADATA_SIZE_OFFSET = 64
VHDX_REGION_TABLE_OFFSET = 192 * units.Ki
VHDX_BS_METADATA_ENTRY_OFFSET = 48
class VHDUtilsV2(vhdutils.VHDUtils):
_VHD_TYPE_DYNAMIC = 3
_VHD_TYPE_DIFFERENCING = 4
_vhd_format_map = {
constants.DISK_FORMAT_VHD: 2,
constants.DISK_FORMAT_VHDX: 3,
}
def __init__(self):
self._vmutils = vmutilsv2.VMUtilsV2()
if sys.platform == 'win32':
self._conn = wmi.WMI(moniker='//./root/virtualization/v2')
def create_dynamic_vhd(self, path, max_internal_size, format):
vhd_format = self._vhd_format_map.get(format)
if not vhd_format:
raise vmutils.HyperVException(_("Unsupported disk format: %s") %
format)
self._create_vhd(self._VHD_TYPE_DYNAMIC, vhd_format, path,
max_internal_size=max_internal_size)
def create_differencing_vhd(self, path, parent_path, size=None):
parent_vhd_info = self.get_vhd_info(parent_path)
self._create_vhd(self._VHD_TYPE_DIFFERENCING,
parent_vhd_info["Format"],
path, parent_path=parent_path,
max_internal_size=size)
def _create_vhd(self, vhd_type, format, path, max_internal_size=None,
parent_path=None):
vhd_info = self._conn.Msvm_VirtualHardDiskSettingData.new()
vhd_info.Type = vhd_type
vhd_info.Format = format
vhd_info.Path = path
vhd_info.ParentPath = parent_path
if max_internal_size:
vhd_info.MaxInternalSize = max_internal_size
image_man_svc = self._conn.Msvm_ImageManagementService()[0]
(job_path, ret_val) = image_man_svc.CreateVirtualHardDisk(
VirtualDiskSettingData=vhd_info.GetText_(1))
self._vmutils.check_ret_val(ret_val, job_path)
def reconnect_parent_vhd(self, child_vhd_path, parent_vhd_path):
image_man_svc = self._conn.Msvm_ImageManagementService()[0]
vhd_info_xml = self._get_vhd_info_xml(image_man_svc, child_vhd_path)
# Can't use ".//PROPERTY[@NAME='ParentPath']/VALUE" due to
# compatibility requirements with Python 2.6
et = ElementTree.fromstring(vhd_info_xml)
for item in et.findall("PROPERTY"):
name = item.attrib["NAME"]
if name == 'ParentPath':
item.find("VALUE").text = parent_vhd_path
break
vhd_info_xml = ElementTree.tostring(et)
(job_path, ret_val) = image_man_svc.SetVirtualHardDiskSettingData(
VirtualDiskSettingData=vhd_info_xml)
self._vmutils.check_ret_val(ret_val, job_path)
def _get_resize_method(self):
image_man_svc = self._conn.Msvm_ImageManagementService()[0]
return image_man_svc.ResizeVirtualHardDisk
def get_internal_vhd_size_by_file_size(self, vhd_path,
new_vhd_file_size):
"""VHDX Size = Header (1 MB)
+ Log
+ Metadata Region
+ BAT
+ Payload Blocks
Chunk size = maximum number of bytes described by a SB block
= 2 ** 23 * LogicalSectorSize
"""
vhd_format = self.get_vhd_format(vhd_path)
if vhd_format == constants.DISK_FORMAT_VHD:
return super(VHDUtilsV2,
self).get_internal_vhd_size_by_file_size(
vhd_path, new_vhd_file_size)
else:
vhd_info = self.get_vhd_info(vhd_path)
vhd_type = vhd_info['Type']
if vhd_type == self._VHD_TYPE_DIFFERENCING:
vhd_parent = self.get_vhd_parent_path(vhd_path)
return self.get_internal_vhd_size_by_file_size(vhd_parent,
new_vhd_file_size)
else:
try:
with open(vhd_path, 'rb') as f:
hs = VHDX_HEADER_SECTION_SIZE
bes = VHDX_BAT_ENTRY_SIZE
lss = vhd_info['LogicalSectorSize']
bs = self._get_vhdx_block_size(f)
ls = self._get_vhdx_log_size(f)
ms = self._get_vhdx_metadata_size_and_offset(f)[0]
chunk_ratio = (1 << 23) * lss / bs
size = new_vhd_file_size
max_internal_size = (bs * chunk_ratio * (size - hs -
ls - ms - bes - bes / chunk_ratio) / (bs *
chunk_ratio + bes * chunk_ratio + bes))
return max_internal_size - (max_internal_size % bs)
except IOError as ex:
raise vmutils.HyperVException(_("Unable to obtain "
"internal size from VHDX: "
"%(vhd_path)s. Exception: "
"%(ex)s") %
{"vhd_path": vhd_path,
"ex": ex})
def _get_vhdx_current_header_offset(self, vhdx_file):
sequence_numbers = []
for offset in VHDX_HEADER_OFFSETS:
vhdx_file.seek(offset + 8)
sequence_numbers.append(struct.unpack('<Q',
vhdx_file.read(8))[0])
current_header = sequence_numbers.index(max(sequence_numbers))
return VHDX_HEADER_OFFSETS[current_header]
def _get_vhdx_log_size(self, vhdx_file):
current_header_offset = self._get_vhdx_current_header_offset(vhdx_file)
offset = current_header_offset + VHDX_LOG_LENGTH_OFFSET
vhdx_file.seek(offset)
log_size = struct.unpack('<I', vhdx_file.read(4))[0]
return log_size
def _get_vhdx_metadata_size_and_offset(self, vhdx_file):
offset = VHDX_METADATA_SIZE_OFFSET + VHDX_REGION_TABLE_OFFSET
vhdx_file.seek(offset)
metadata_offset = struct.unpack('<Q', vhdx_file.read(8))[0]
metadata_size = struct.unpack('<I', vhdx_file.read(4))[0]
return metadata_size, metadata_offset
def _get_vhdx_block_size(self, vhdx_file):
metadata_offset = self._get_vhdx_metadata_size_and_offset(vhdx_file)[1]
offset = metadata_offset + VHDX_BS_METADATA_ENTRY_OFFSET
vhdx_file.seek(offset)
file_parameter_offset = struct.unpack('<I', vhdx_file.read(4))[0]
vhdx_file.seek(file_parameter_offset + metadata_offset)
block_size = struct.unpack('<I', vhdx_file.read(4))[0]
return block_size
def _get_vhd_info_xml(self, image_man_svc, vhd_path):
(job_path,
ret_val,
vhd_info_xml) = image_man_svc.GetVirtualHardDiskSettingData(vhd_path)
self._vmutils.check_ret_val(ret_val, job_path)
return vhd_info_xml.encode('utf8', 'xmlcharrefreplace')
def get_vhd_info(self, vhd_path):
image_man_svc = self._conn.Msvm_ImageManagementService()[0]
vhd_info_xml = self._get_vhd_info_xml(image_man_svc, vhd_path)
vhd_info_dict = {}
et = ElementTree.fromstring(vhd_info_xml)
for item in et.findall("PROPERTY"):
name = item.attrib["NAME"]
value_text = item.find("VALUE").text
if name in ["Path", "ParentPath"]:
vhd_info_dict[name] = value_text
elif name in ["BlockSize", "LogicalSectorSize",
"PhysicalSectorSize", "MaxInternalSize"]:
vhd_info_dict[name] = long(value_text)
elif name in ["Type", "Format"]:
vhd_info_dict[name] = int(value_text)
return vhd_info_dict
def get_best_supported_vhd_format(self):
return constants.DISK_FORMAT_VHDX
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