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40b5967fc3
New modules btrfs_subvolume / btrfs_info (#5832)
* Initial implementation for new modules btrfs_subvolume and btrfs_info
* Improve/flesh out documentation. Add ability to target filesystem by uuid, label or device. Update tests to test targeting filesystem by each supported parameter and when only mountpoint.
* Updates for btrfs modules. Add missing copyright notices. Switch options to contains in return documentation. Update btrfs_subvolume to always use closest parent mount.
* Add maintainers for btrfs module(s) and remove unused class member cause lint failure.
* Add changelog fragment. Attempt to only run against the VMs as part of CI.
* Updates per code review. Remove changelog fragment. Switch use of map to list comprehension. Add trailing comma to last item in multi-line dicts. Clean up documentation with complete senstences for descriptions and correct/consistent use of macros.
* Improved error handling in btrfs_subvolume module: add custom exception type, favor exceptions over immediate call to fail_json and add single top level return for failure scenarios. Normalize name and snapshot_source parameters early in module execution and remove unecessary duplicate normalization throughout processing.
* Add azp/posix/3 to aliases per feedback
* Clean up automatic mounting. Prevent automount when check_mode=True. Immediately fail if a mount is identified as required and automount=True. Identify the minimal subset of subvolumes that need to be mounted instead of just finding a single common root.
* Skip btrfs_subvolume integration tests if btrfs-progs isn't successfully installed.
* Bump version_added for btrfs modules to 6.6.0. Ensure consistent trailing punctuation for module descriptions and document check_mode behavior as attribute description rather than a module level note.
* Remove unused imports from btrfs_subvolume module.
* Fix import.
* Docs improvements.
---------
Co-authored-by: Felix Fontein <felix@fontein.de>
(cherry picked from commit ae5090d90e)
Co-authored-by: Gregory Furlong <50386272+gnfzdz@users.noreply.github.com>
464 lines
17 KiB
Python
464 lines
17 KiB
Python
# Copyright (c) 2022, Gregory Furlong <gnfzdz@fzdz.io>
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# GNU General Public License v3.0+ (see COPYING or https://www.gnu.org/licenses/gpl-3.0.txt)
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# SPDX-License-Identifier: GPL-3.0-or-later
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from __future__ import (absolute_import, division, print_function)
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__metaclass__ = type
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from ansible.module_utils.common.text.converters import to_bytes
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import re
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import os
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def normalize_subvolume_path(path):
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"""
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Normalizes btrfs subvolume paths to ensure exactly one leading slash, no trailing slashes and no consecutive slashes.
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In addition, if the path is prefixed with a leading <FS_TREE>, this value is removed.
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"""
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fstree_stripped = re.sub(r'^<FS_TREE>', '', path)
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result = re.sub(r'/+$', '', re.sub(r'/+', '/', '/' + fstree_stripped))
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return result if len(result) > 0 else '/'
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class BtrfsModuleException(Exception):
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pass
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class BtrfsCommands(object):
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"""
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Provides access to a subset of the Btrfs command line
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"""
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def __init__(self, module):
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self.__module = module
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self.__btrfs = self.__module.get_bin_path("btrfs", required=True)
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def filesystem_show(self):
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command = "%s filesystem show -d" % (self.__btrfs)
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result = self.__module.run_command(command, check_rc=True)
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stdout = [x.strip() for x in result[1].splitlines()]
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filesystems = []
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current = None
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for line in stdout:
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if line.startswith('Label'):
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current = self.__parse_filesystem(line)
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filesystems.append(current)
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elif line.startswith('devid'):
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current['devices'].append(self.__parse_filesystem_device(line))
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return filesystems
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def __parse_filesystem(self, line):
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label = re.sub(r'\s*uuid:.*$', '', re.sub(r'^Label:\s*', '', line))
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id = re.sub(r'^.*uuid:\s*', '', line)
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filesystem = {}
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filesystem['label'] = label.strip("'") if label != 'none' else None
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filesystem['uuid'] = id
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filesystem['devices'] = []
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filesystem['mountpoints'] = []
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filesystem['subvolumes'] = []
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filesystem['default_subvolid'] = None
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return filesystem
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def __parse_filesystem_device(self, line):
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return re.sub(r'^.*path\s', '', line)
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def subvolumes_list(self, filesystem_path):
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command = "%s subvolume list -tap %s" % (self.__btrfs, filesystem_path)
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result = self.__module.run_command(command, check_rc=True)
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stdout = [x.split('\t') for x in result[1].splitlines()]
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subvolumes = [{'id': 5, 'parent': None, 'path': '/'}]
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if len(stdout) > 2:
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subvolumes.extend([self.__parse_subvolume_list_record(x) for x in stdout[2:]])
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return subvolumes
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def __parse_subvolume_list_record(self, item):
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return {
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'id': int(item[0]),
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'parent': int(item[2]),
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'path': normalize_subvolume_path(item[5]),
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}
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def subvolume_get_default(self, filesystem_path):
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command = [self.__btrfs, "subvolume", "get-default", to_bytes(filesystem_path)]
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result = self.__module.run_command(command, check_rc=True)
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# ID [n] ...
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return int(result[1].strip().split()[1])
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def subvolume_set_default(self, filesystem_path, subvolume_id):
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command = [self.__btrfs, "subvolume", "set-default", str(subvolume_id), to_bytes(filesystem_path)]
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result = self.__module.run_command(command, check_rc=True)
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def subvolume_create(self, subvolume_path):
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command = [self.__btrfs, "subvolume", "create", to_bytes(subvolume_path)]
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result = self.__module.run_command(command, check_rc=True)
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def subvolume_snapshot(self, snapshot_source, snapshot_destination):
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command = [self.__btrfs, "subvolume", "snapshot", to_bytes(snapshot_source), to_bytes(snapshot_destination)]
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result = self.__module.run_command(command, check_rc=True)
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def subvolume_delete(self, subvolume_path):
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command = [self.__btrfs, "subvolume", "delete", to_bytes(subvolume_path)]
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result = self.__module.run_command(command, check_rc=True)
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class BtrfsInfoProvider(object):
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"""
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Utility providing details of the currently available btrfs filesystems
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"""
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def __init__(self, module):
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self.__module = module
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self.__btrfs_api = BtrfsCommands(module)
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self.__findmnt_path = self.__module.get_bin_path("findmnt", required=True)
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def get_filesystems(self):
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filesystems = self.__btrfs_api.filesystem_show()
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mountpoints = self.__find_mountpoints()
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for filesystem in filesystems:
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device_mountpoints = self.__filter_mountpoints_for_devices(mountpoints, filesystem['devices'])
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filesystem['mountpoints'] = device_mountpoints
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if len(device_mountpoints) > 0:
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# any path within the filesystem can be used to query metadata
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mountpoint = device_mountpoints[0]['mountpoint']
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filesystem['subvolumes'] = self.get_subvolumes(mountpoint)
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filesystem['default_subvolid'] = self.get_default_subvolume_id(mountpoint)
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return filesystems
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def get_mountpoints(self, filesystem_devices):
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mountpoints = self.__find_mountpoints()
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return self.__filter_mountpoints_for_devices(mountpoints, filesystem_devices)
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def get_subvolumes(self, filesystem_path):
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return self.__btrfs_api.subvolumes_list(filesystem_path)
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def get_default_subvolume_id(self, filesystem_path):
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return self.__btrfs_api.subvolume_get_default(filesystem_path)
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def __filter_mountpoints_for_devices(self, mountpoints, devices):
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return [m for m in mountpoints if (m['device'] in devices)]
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def __find_mountpoints(self):
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command = "%s -t btrfs -nvP" % self.__findmnt_path
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result = self.__module.run_command(command)
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mountpoints = []
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if result[0] == 0:
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lines = result[1].splitlines()
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for line in lines:
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mountpoint = self.__parse_mountpoint_pairs(line)
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mountpoints.append(mountpoint)
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return mountpoints
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def __parse_mountpoint_pairs(self, line):
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pattern = re.compile(r'^TARGET="(?P<target>.*)"\s+SOURCE="(?P<source>.*)"\s+FSTYPE="(?P<fstype>.*)"\s+OPTIONS="(?P<options>.*)"\s*$')
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match = pattern.search(line)
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if match is not None:
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groups = match.groupdict()
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return {
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'mountpoint': groups['target'],
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'device': groups['source'],
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'subvolid': self.__extract_mount_subvolid(groups['options']),
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}
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else:
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raise BtrfsModuleException("Failed to parse findmnt result for line: '%s'" % line)
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def __extract_mount_subvolid(self, mount_options):
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for option in mount_options.split(','):
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if option.startswith('subvolid='):
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return int(option[len('subvolid='):])
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raise BtrfsModuleException("Failed to find subvolid for mountpoint in options '%s'" % mount_options)
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class BtrfsSubvolume(object):
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"""
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Wrapper class providing convenience methods for inspection of a btrfs subvolume
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"""
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def __init__(self, filesystem, subvolume_id):
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self.__filesystem = filesystem
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self.__subvolume_id = subvolume_id
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def get_filesystem(self):
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return self.__filesystem
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def is_mounted(self):
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mountpoints = self.get_mountpoints()
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return mountpoints is not None and len(mountpoints) > 0
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def is_filesystem_root(self):
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return 5 == self.__subvolume_id
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def is_filesystem_default(self):
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return self.__filesystem.default_subvolid == self.__subvolume_id
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def get_mounted_path(self):
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mountpoints = self.get_mountpoints()
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if mountpoints is not None and len(mountpoints) > 0:
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return mountpoints[0]
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elif self.parent is not None:
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parent = self.__filesystem.get_subvolume_by_id(self.parent)
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parent_path = parent.get_mounted_path()
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if parent_path is not None:
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return parent_path + os.path.sep + self.name
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else:
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return None
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def get_mountpoints(self):
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return self.__filesystem.get_mountpoints_by_subvolume_id(self.__subvolume_id)
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def get_child_relative_path(self, absolute_child_path):
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"""
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Get the relative path from this subvolume to the named child subvolume.
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The provided parameter is expected to be normalized as by normalize_subvolume_path.
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"""
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path = self.path
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if absolute_child_path.startswith(path):
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relative = absolute_child_path[len(path):]
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return re.sub(r'^/*', '', relative)
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else:
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raise BtrfsModuleException("Path '%s' doesn't start with '%s'" % (absolute_child_path, path))
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def get_parent_subvolume(self):
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parent_id = self.parent
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return self.__filesystem.get_subvolume_by_id(parent_id) if parent_id is not None else None
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def get_child_subvolumes(self):
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return self.__filesystem.get_subvolume_children(self.__subvolume_id)
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@property
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def __info(self):
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return self.__filesystem.get_subvolume_info_for_id(self.__subvolume_id)
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@property
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def id(self):
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return self.__subvolume_id
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@property
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def name(self):
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return self.path.split('/').pop()
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@property
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def path(self):
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return self.__info['path']
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@property
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def parent(self):
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return self.__info['parent']
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class BtrfsFilesystem(object):
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"""
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Wrapper class providing convenience methods for inspection of a btrfs filesystem
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"""
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def __init__(self, info, provider, module):
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self.__provider = provider
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# constant for module execution
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self.__uuid = info['uuid']
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self.__label = info['label']
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self.__devices = info['devices']
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# refreshable
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self.__default_subvolid = info['default_subvolid'] if 'default_subvolid' in info else None
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self.__update_mountpoints(info['mountpoints'] if 'mountpoints' in info else [])
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self.__update_subvolumes(info['subvolumes'] if 'subvolumes' in info else [])
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@property
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def uuid(self):
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return self.__uuid
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@property
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def label(self):
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return self.__label
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@property
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def default_subvolid(self):
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return self.__default_subvolid
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@property
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def devices(self):
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return list(self.__devices)
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def refresh(self):
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self.refresh_mountpoints()
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self.refresh_subvolumes()
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self.refresh_default_subvolume()
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def refresh_mountpoints(self):
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mountpoints = self.__provider.get_mountpoints(list(self.__devices))
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self.__update_mountpoints(mountpoints)
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def __update_mountpoints(self, mountpoints):
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self.__mountpoints = dict()
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for i in mountpoints:
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subvolid = i['subvolid']
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mountpoint = i['mountpoint']
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if subvolid not in self.__mountpoints:
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self.__mountpoints[subvolid] = []
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self.__mountpoints[subvolid].append(mountpoint)
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def refresh_subvolumes(self):
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filesystem_path = self.get_any_mountpoint()
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if filesystem_path is not None:
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subvolumes = self.__provider.get_subvolumes(filesystem_path)
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self.__update_subvolumes(subvolumes)
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def __update_subvolumes(self, subvolumes):
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# TODO strategy for retaining information on deleted subvolumes?
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self.__subvolumes = dict()
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for subvolume in subvolumes:
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self.__subvolumes[subvolume['id']] = subvolume
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def refresh_default_subvolume(self):
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filesystem_path = self.get_any_mountpoint()
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if filesystem_path is not None:
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self.__default_subvolid = self.__provider.get_default_subvolume_id(filesystem_path)
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def contains_device(self, device):
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return device in self.__devices
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def contains_subvolume(self, subvolume):
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return self.get_subvolume_by_name(subvolume) is not None
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def get_subvolume_by_id(self, subvolume_id):
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return BtrfsSubvolume(self, subvolume_id) if subvolume_id in self.__subvolumes else None
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def get_subvolume_info_for_id(self, subvolume_id):
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return self.__subvolumes[subvolume_id] if subvolume_id in self.__subvolumes else None
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def get_subvolume_by_name(self, subvolume):
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for subvolume_info in self.__subvolumes.values():
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if subvolume_info['path'] == subvolume:
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return BtrfsSubvolume(self, subvolume_info['id'])
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return None
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def get_any_mountpoint(self):
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for subvol_mountpoints in self.__mountpoints.values():
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if len(subvol_mountpoints) > 0:
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return subvol_mountpoints[0]
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# maybe error?
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return None
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def get_any_mounted_subvolume(self):
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for subvolid, subvol_mountpoints in self.__mountpoints.items():
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if len(subvol_mountpoints) > 0:
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return self.get_subvolume_by_id(subvolid)
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return None
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def get_mountpoints_by_subvolume_id(self, subvolume_id):
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return self.__mountpoints[subvolume_id] if subvolume_id in self.__mountpoints else []
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def get_nearest_subvolume(self, subvolume):
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"""Return the identified subvolume if existing, else the closest matching parent"""
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subvolumes_by_path = self.__get_subvolumes_by_path()
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while len(subvolume) > 1:
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if subvolume in subvolumes_by_path:
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return BtrfsSubvolume(self, subvolumes_by_path[subvolume]['id'])
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else:
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subvolume = re.sub(r'/[^/]+$', '', subvolume)
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return BtrfsSubvolume(self, 5)
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def get_mountpath_as_child(self, subvolume_name):
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"""Find a path to the target subvolume through a mounted ancestor"""
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nearest = self.get_nearest_subvolume(subvolume_name)
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if nearest.path == subvolume_name:
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nearest = nearest.get_parent_subvolume()
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if nearest is None or nearest.get_mounted_path() is None:
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raise BtrfsModuleException("Failed to find a path '%s' through a mounted parent subvolume" % subvolume_name)
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else:
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return nearest.get_mounted_path() + os.path.sep + nearest.get_child_relative_path(subvolume_name)
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def get_subvolume_children(self, subvolume_id):
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return [BtrfsSubvolume(self, x['id']) for x in self.__subvolumes.values() if x['parent'] == subvolume_id]
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def __get_subvolumes_by_path(self):
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result = {}
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for s in self.__subvolumes.values():
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path = s['path']
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result[path] = s
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return result
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def is_mounted(self):
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return self.__mountpoints is not None and len(self.__mountpoints) > 0
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def get_summary(self):
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subvolumes = []
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sources = self.__subvolumes.values() if self.__subvolumes is not None else []
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for subvolume in sources:
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id = subvolume['id']
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subvolumes.append({
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'id': id,
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'path': subvolume['path'],
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'parent': subvolume['parent'],
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'mountpoints': self.get_mountpoints_by_subvolume_id(id),
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})
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return {
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'default_subvolume': self.__default_subvolid,
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'devices': self.__devices,
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'label': self.__label,
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'uuid': self.__uuid,
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'subvolumes': subvolumes,
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}
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class BtrfsFilesystemsProvider(object):
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"""
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Provides methods to query available btrfs filesystems
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"""
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def __init__(self, module):
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self.__module = module
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self.__provider = BtrfsInfoProvider(module)
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self.__filesystems = None
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def get_matching_filesystem(self, criteria):
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if criteria['device'] is not None:
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criteria['device'] = os.path.realpath(criteria['device'])
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self.__check_init()
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matching = [f for f in self.__filesystems.values() if self.__filesystem_matches_criteria(f, criteria)]
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if len(matching) == 1:
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return matching[0]
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else:
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raise BtrfsModuleException("Found %d filesystems matching criteria uuid=%s label=%s device=%s" % (
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len(matching),
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criteria['uuid'],
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criteria['label'],
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criteria['device']
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))
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def __filesystem_matches_criteria(self, filesystem, criteria):
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return ((criteria['uuid'] is None or filesystem.uuid == criteria['uuid']) and
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(criteria['label'] is None or filesystem.label == criteria['label']) and
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(criteria['device'] is None or filesystem.contains_device(criteria['device'])))
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def get_filesystem_for_device(self, device):
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real_device = os.path.realpath(device)
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self.__check_init()
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for fs in self.__filesystems.values():
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if fs.contains_device(real_device):
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return fs
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return None
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def get_filesystems(self):
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self.__check_init()
|
|
return list(self.__filesystems.values())
|
|
|
|
def __check_init(self):
|
|
if self.__filesystems is None:
|
|
self.__filesystems = dict()
|
|
for f in self.__provider.get_filesystems():
|
|
uuid = f['uuid']
|
|
self.__filesystems[uuid] = BtrfsFilesystem(f, self.__provider, self.__module)
|