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import pathlib
import logging
from typing import Optional
from ...exceptions import SysCallError, DiskError
from ...general import SysCommand
from ...output import log
from ..helpers import get_mount_info
from .btrfssubvolume import BtrfsSubvolume
def mount_subvolume(installation, device, name, subvolume_information):
# we normalize the subvolume name (getting rid of slash at the start if exists. In our implemenation has no semantic load.
# Every subvolume is created from the top of the hierarchy- and simplifies its further use
name = name.lstrip('/')
# renormalize the right hand.
mountpoint = subvolume_information.get('mountpoint', None)
if not mountpoint:
return None
if type(mountpoint) == str:
mountpoint = pathlib.Path(mountpoint)
installation_target = installation.target
if type(installation_target) == str:
installation_target = pathlib.Path(installation_target)
mountpoint = installation_target / mountpoint.relative_to(mountpoint.anchor)
mountpoint.mkdir(parents=True, exist_ok=True)
mount_options = subvolume_information.get('options', [])
if not any('subvol=' in x for x in mount_options):
mount_options += [f'subvol={name}']
log(f"Mounting subvolume {name} on {device} to {mountpoint}", level=logging.INFO, fg="gray")
SysCommand(f"mount {device.path} {mountpoint} -o {','.join(mount_options)}")
def setup_subvolumes(installation, partition_dict):
"""
Taken from: ..user_guides.py
partition['btrfs'] = {
"subvolumes" : {
"@": "/",
"@home": "/home",
"@log": "/var/log",
"@pkg": "/var/cache/pacman/pkg",
"@.snapshots": "/.snapshots"
}
}
"""
log(f"Setting up subvolumes: {partition_dict['btrfs']['subvolumes']}", level=logging.INFO, fg="gray")
for name, right_hand in partition_dict['btrfs']['subvolumes'].items():
# we normalize the subvolume name (getting rid of slash at the start if exists. In our implemenation has no semantic load.
# Every subvolume is created from the top of the hierarchy- and simplifies its further use
name = name.lstrip('/')
# renormalize the right hand.
# mountpoint = None
subvol_options = []
match right_hand:
# case str(): # backwards-compatability
# mountpoint = right_hand
case dict():
# mountpoint = right_hand.get('mountpoint', None)
subvol_options = right_hand.get('options', [])
# We create the subvolume using the BTRFSPartition instance.
# That way we ensure not only easy access, but also accurate mount locations etc.
partition_dict['device_instance'].create_subvolume(name, installation=installation)
# Make the nodatacow processing now
# It will be the main cause of creation of subvolumes which are not to be mounted
# it is not an options which can be established by subvolume (but for whole file systems), and can be
# set up via a simple attribute change in a directory (if empty). And here the directories are brand new
if 'nodatacow' in subvol_options:
if (cmd := SysCommand(f"chattr +C {installation.target}/{name}")).exit_code != 0:
raise DiskError(f"Could not set nodatacow attribute at {installation.target}/{name}: {cmd}")
# entry is deleted so nodatacow doesn't propagate to the mount options
del subvol_options[subvol_options.index('nodatacow')]
# Make the compress processing now
# it is not an options which can be established by subvolume (but for whole file systems), and can be
# set up via a simple attribute change in a directory (if empty). And here the directories are brand new
# in this way only zstd compression is activaded
# TODO WARNING it is not clear if it should be a standard feature, so it might need to be deactivated
if 'compress' in subvol_options:
if not any(['compress' in filesystem_option for filesystem_option in partition_dict.get('filesystem', {}).get('mount_options', [])]):
if (cmd := SysCommand(f"chattr +c {installation.target}/{name}")).exit_code != 0:
raise DiskError(f"Could not set compress attribute at {installation.target}/{name}: {cmd}")
# entry is deleted so compress doesn't propagate to the mount options
del subvol_options[subvol_options.index('compress')]
def subvolume_info_from_path(path :pathlib.Path) -> Optional[BtrfsSubvolume]:
try:
subvolume_name = None
result = {}
for index, line in enumerate(SysCommand(f"btrfs subvolume show {path}")):
if index == 0:
subvolume_name = line.strip().decode('UTF-8')
continue
if b':' in line:
key, value = line.strip().decode('UTF-8').split(':', 1)
# A bit of a hack, until I figure out how @dataclass
# allows for hooking in a pre-processor to do this we have to do it here:
result[key.lower().replace(' ', '_').replace('(s)', 's')] = value.strip()
return BtrfsSubvolume(**{'full_path' : path, 'name' : subvolume_name, **result})
except SysCallError:
pass
return None
def find_parent_subvolume(path :pathlib.Path, filters=[]):
# A root path cannot have a parent
if str(path) == '/':
return None
if found_mount := get_mount_info(str(path.parent), traverse=True, ignore=filters):
if not (subvolume := subvolume_info_from_path(found_mount['target'])):
if found_mount['target'] == '/':
return None
return find_parent_subvolume(path.parent, traverse=True, filters=[*filters, found_mount['target']])
return subvolume
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