230 lines
9.2 KiB
Python
230 lines
9.2 KiB
Python
# Copyright 2016 Andreas Florath (andreas@florath.net)
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#
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# Licensed under the Apache License, Version 2.0 (the "License"); you may
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# not use this file except in compliance with the License. You may obtain
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# a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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# License for the specific language governing permissions and limitations
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# under the License.
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import logging
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import os
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from diskimage_builder.block_device.exception import \
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BlockDeviceSetupException
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from diskimage_builder.block_device.level1.mbr import MBR
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from diskimage_builder.block_device.level1.partition import PartitionNode
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from diskimage_builder.block_device.plugin import PluginBase
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from diskimage_builder.block_device.utils import exec_sudo
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from diskimage_builder.block_device.utils import parse_abs_size_spec
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from diskimage_builder.block_device.utils import parse_rel_size_spec
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logger = logging.getLogger(__name__)
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class Partitioning(PluginBase):
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def __init__(self, config, default_config, state):
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logger.debug("Creating Partitioning object; config [%s]", config)
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super(Partitioning, self).__init__()
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# Unlike other PluginBase we are somewhat persistent, as the
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# partition nodes call back to us (see create() below). We
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# need to keep this reference.
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self.state = state
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# Because using multiple partitions of one base is done
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# within one object, there is the need to store a flag if the
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# creation of the partitions was already done.
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self.already_created = False
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self.already_cleaned = False
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# Parameter check
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if 'base' not in config:
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raise BlockDeviceSetupException("Partitioning config needs 'base'")
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self.base = config['base']
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if 'partitions' not in config:
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raise BlockDeviceSetupException(
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"Partitioning config needs 'partitions'")
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if 'label' not in config:
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raise BlockDeviceSetupException(
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"Partitioning config needs 'label'")
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self.label = config['label']
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if self.label not in ("mbr", "gpt"):
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raise BlockDeviceSetupException("Label must be 'mbr' or 'gpt'")
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# It is VERY important to get the alignment correct. If this
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# is not correct, the disk performance might be very poor.
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# Example: In some tests a 'off by one' leads to a write
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# performance of 30% compared to a correctly aligned
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# partition.
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# The problem for DIB is, that it cannot assume that the host
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# system uses the same IO sizes as the target system,
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# therefore here a fixed approach (as used in all modern
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# systems with large disks) is used. The partitions are
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# aligned to 1MiB (which are about 2048 times 512 bytes
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# blocks)
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self.align = 1024 * 1024 # 1MiB as default
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if 'align' in config:
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self.align = parse_abs_size_spec(config['align'])
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self.partitions = []
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prev_partition = None
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for part_cfg in config['partitions']:
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np = PartitionNode(part_cfg, state, self, prev_partition)
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self.partitions.append(np)
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prev_partition = np
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def get_nodes(self):
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# return the list of partitions
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return self.partitions
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def _size_of_block_dev(self, dev):
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with open(dev, "r") as fd:
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fd.seek(0, 2)
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return fd.tell()
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def _create_mbr(self):
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"""Create partitions with MBR"""
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with MBR(self.image_path, self.disk_size, self.align) as part_impl:
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for part_cfg in self.partitions:
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part_name = part_cfg.get_name()
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part_bootflag = PartitionNode.flag_boot \
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in part_cfg.get_flags()
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part_primary = PartitionNode.flag_primary \
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in part_cfg.get_flags()
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part_size = part_cfg.get_size()
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part_free = part_impl.free()
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part_type = part_cfg.get_type()
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logger.debug("Not partitioned space [%d]", part_free)
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part_size = parse_rel_size_spec(part_size,
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part_free)[1]
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part_no \
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= part_impl.add_partition(part_primary, part_bootflag,
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part_size, part_type)
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logger.debug("Create partition [%s] [%d]",
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part_name, part_no)
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# We're going to mount all partitions with kpartx
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# below once we're done. So the device this partition
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# will be seen at becomes "/dev/mapper/loop0pX"
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assert self.device_path[:5] == "/dev/"
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partition_device_name = "/dev/mapper/%sp%d" % \
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(self.device_path[5:], part_no)
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self.state['blockdev'][part_name] \
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= {'device': partition_device_name}
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def _create_gpt(self):
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"""Create partitions with GPT"""
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cmd = ['sgdisk', self.image_path]
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# This padding gives us a little room for rounding so we don't
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# go over the end of the disk
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disk_free = self.disk_size - (2048 * 1024)
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pnum = 1
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for p in self.partitions:
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args = {}
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args['pnum'] = pnum
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args['name'] = '%s' % p.get_name()
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args['type'] = '%s' % p.get_type()
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# convert from a relative/string size to bytes
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size = parse_rel_size_spec(p.get_size(), disk_free)[1]
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# We keep track in bytes, but specify things to sgdisk in
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# megabytes so it can align on sensible boundaries. And
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# create partitions right after previous so no need to
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# calculate start/end - just size.
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assert size <= disk_free
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args['size'] = size // (1024 * 1024)
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new_cmd = ("-n", "{pnum}:0:+{size}M".format(**args),
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"-t", "{pnum}:{type}".format(**args),
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# Careful with this one, as {name} could have spaces
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"-c", "{pnum}:{name}".format(**args))
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cmd.extend(new_cmd)
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# Fill the state; we mount all partitions with kpartx
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# below once we're done. So the device this partition
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# will be seen at becomes "/dev/mapper/loop0pX"
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assert self.device_path[:5] == "/dev/"
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device_name = "/dev/mapper/%sp%d" % (self.device_path[5:], pnum)
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self.state['blockdev'][p.get_name()] \
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= {'device': device_name}
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disk_free = disk_free - size
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pnum = pnum + 1
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logger.debug("Partition %s added, %s remaining in disk",
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pnum, disk_free)
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logger.debug("cmd: %s", ' '.join(cmd))
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exec_sudo(cmd)
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# not this is NOT a node and this is not called directly! The
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# create() calls in the partition nodes this plugin has
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# created are calling back into this.
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def create(self):
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# This is a bit of a hack. Each of the partitions is actually
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# in the graph, so for every partition we get a create() call
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# as the walk happens. But we only need to create the
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# partition table once...
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if self.already_created:
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logger.info("Not creating the partitions a second time.")
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return
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self.already_created = True
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# the raw file on disk
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self.image_path = self.state['blockdev'][self.base]['image']
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# the /dev/loopX device of the parent
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self.device_path = self.state['blockdev'][self.base]['device']
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# underlying size
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self.disk_size = self._size_of_block_dev(self.image_path)
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logger.info("Creating partition on [%s] [%s]",
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self.base, self.image_path)
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assert self.label in ('mbr', 'gpt')
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if self.label == 'mbr':
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self._create_mbr()
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elif self.label == 'gpt':
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self._create_gpt()
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# "saftey sync" to make sure the partitions are written
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exec_sudo(["sync"])
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# now all the partitions are created, get device-mapper to
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# mount them
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if not os.path.exists("/.dockerenv"):
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exec_sudo(["kpartx", "-avs", self.device_path])
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else:
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# If running inside Docker, make our nodes manually,
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# because udev will not be working. kpartx cannot run in
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# sync mode in docker.
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exec_sudo(["kpartx", "-av", self.device_path])
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exec_sudo(["dmsetup", "--noudevsync", "mknodes"])
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return
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def cleanup(self):
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# remove the partition mappings made for the parent
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# block-device by create() above. this is called from the
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# child PartitionNode umount/delete/cleanup. Thus every
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# partition calls it, but we only want to do it once and our
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# gate.
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if not self.already_cleaned:
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self.already_cleaned = True
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exec_sudo(["kpartx", "-d",
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self.state['blockdev'][self.base]['device']])
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