def get_vhd_format(self, vhd_path):
vhd_format = os.path.splitext(vhd_path)[1][1:].upper()
device_id = vdisk_const.DEVICE_ID_MAP.get(vhd_format)
# If the disk format is not recognised by extension,
# we attempt to retrieve it by seeking the signature.
if not device_id and os.path.exists(vhd_path):
vhd_format = self._get_vhd_format_by_signature(vhd_path)
if not vhd_format:
raise exceptions.VHDException(
_("Could not retrieve VHD format: %s") % vhd_path)
return vhd_format
def _check_resize_needed(self, vhd_path, new_size):
curr_size = self.get_vhd_size(vhd_path)['VirtualSize']
if curr_size > new_size:
err_msg = _("Cannot resize image %(vhd_path)s "
"to a smaller size. "
"Image virtual size: %(curr_size)s, "
"Requested virtual size: %(new_size)s")
raise exceptions.VHDException(err_msg % dict(
vhd_path=vhd_path, curr_size=curr_size, new_size=new_size))
elif curr_size == new_size:
LOG.debug(
"Skipping resizing %(vhd_path)s to %(new_size)s"
"as it already has the requested size.",
dict(vhd_path=vhd_path, new_size=new_size))
return False
return True
def _get_internal_vhdx_size_by_file_size(self, vhd_path, new_vhd_file_size,
vhd_info):
"""VHDX Size:
Header (1MB) + Log + Metadata Region + BAT + Payload Blocks
The chunk size is the maximum number of bytes described by a SB
block.
Chunk size = 2^{23} * SectorSize
:param str vhd_path: VHD file path
:param new_vhd_file_size: Size of the new VHD file.
:return: Internal VHD size according to new VHD file size.
"""
try:
with open(vhd_path, 'rb') as f:
hs = vdisk_const.VHDX_HEADER_SECTION_SIZE
bes = vdisk_const.VHDX_BAT_ENTRY_SIZE
lss = vhd_info['SectorSize']
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 exceptions.VHDException(
_("Unable to obtain internal size from VHDX: "
"%(vhd_path)s. Exception: %(ex)s") % {
"vhd_path": vhd_path,
"ex": ex
})
