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# Copyright 2010, 2011 Lars Wirzenius
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
import logging
import sys
import tracing
import ttystatus
import larch
class Error(larch.Error):
def __init__(self, msg):
self.msg = 'Assertion failed: %s' % msg
class WorkItem(object):
'''A work item for fsck.
Subclass can optionally set the ``name`` attribute; the class name
is used by default.
'''
def __str__(self):
if hasattr(self, 'name'):
return self.name
else:
return self.__class__.__name__
def do(self):
pass
def __iter__(self):
return iter([self])
def warning(self, msg):
self.fsck.warning('warning: %s: %s' % (self.name, msg))
def error(self, msg):
self.fsck.error('ERROR: %s: %s' % (self.name, msg))
def get_node(self, node_id):
tracing.trace('node_id=%s' % node_id)
try:
return self.fsck.forest.node_store.get_node(node_id)
except larch.NodeMissing:
self.error(
'forest %s: node %s is missing' %
(self.fsck.forest_name, node_id))
def start_modification(self, node):
self.fsck.forest.node_store.start_modification(node)
def put_node(self, node):
tracing.trace('node.id=%s' % node.id)
return self.fsck.forest.node_store.put_node(node)
class CheckIndexNode(WorkItem):
def __init__(self, fsck, node):
self.fsck = fsck
self.node = node
self.name = (
'CheckIndexNode: checking index node %s in %s' %
(self.node.id, self.fsck.forest_name))
def do(self):
tracing.trace('node.id=%s' % self.node.id)
if type(self.node) != larch.IndexNode:
self.error(
'forest %s: node %s: '
'Expected to get an index node, got %s instead' %
(self.fsck.forest_name, self.node.id, type(self.node)))
return
if len(self.node) == 0:
self.error('forest %s: index node %s: No children' %
(self.fsck.forest_name, self.node.id))
return
# Increase refcounts for all children, and check that the child
# nodes exist. If the children are index nodes, create work
# items to check those. Leaf nodes get no further checking.
drop_keys = []
for key in self.node:
child_id = self.node[key]
seen_already = child_id in self.fsck.refcounts
self.fsck.count(child_id)
if not seen_already:
child = self.get_node(child_id)
if child is None:
drop_keys.append(key)
elif type(child) == larch.IndexNode:
yield CheckIndexNode(self.fsck, child)
# Fix references to missing children by dropping them.
if self.fsck.fix and drop_keys:
self.start_modification(self.node)
for key in drop_keys:
self.node.remove(key)
self.warning('index node %s: dropped key %s' %
(self.node.id, key))
self.put_node(self.node)
class CheckForest(WorkItem):
def __init__(self, fsck):
self.fsck = fsck
self.name = 'CheckForest: forest %s' % self.fsck.forest_name
def do(self):
tracing.trace("CheckForest: checking forest %s" % self.name )
for tree in self.fsck.forest.trees:
self.fsck.count(tree.root.id)
root_node = self.get_node(tree.root.id)
tracing.trace('root_node.id=%s' % root_node.id)
yield CheckIndexNode(self.fsck, root_node)
class CheckRefcounts(WorkItem):
def __init__(self, fsck):
self.fsck = fsck
self.name = 'CheckRefcounts: refcounts in %s' % self.fsck.forest_name
def do(self):
tracing.trace(
'CheckRefcounts : %s nodes to check' %
len(self.fsck.refcounts) )
for node_id in self.fsck.refcounts:
tracing.trace('CheckRefcounts checking node %s' % node_id)
refcount = self.fsck.forest.node_store.get_refcount(node_id)
if refcount != self.fsck.refcounts[node_id]:
self.error(
'forest %s: node %s: refcount is %s but should be %s' %
(self.fsck.forest_name,
node_id,
refcount,
self.fsck.refcounts[node_id]))
if self.fsck.fix:
self.fsck.forest.node_store.set_refcount(
node_id, self.fsck.refcounts[node_id])
self.warning('node %s: refcount was set to %s' %
(node_id, self.fsck.refcounts[node_id]))
class CommitForest(WorkItem):
def __init__(self, fsck):
self.fsck = fsck
self.name = ('CommitForest: committing fixes to %s' %
self.fsck.forest_name)
def do(self):
tracing.trace('committing changes to %s' % self.fsck.forest_name)
self.fsck.forest.commit()
class Fsck(object):
'''Verify internal consistency of a larch.Forest.'''
def __init__(self, forest, warning, error, fix):
self.forest = forest
self.forest_name = getattr(
forest.node_store, 'dirname', 'in-memory forest')
self.warning = warning
self.error = error
self.fix = fix
self.refcounts = {}
def find_work(self):
yield CheckForest(self)
yield CheckRefcounts(self)
if self.fix:
yield CommitForest(self)
def count(self, node_id):
self.refcounts[node_id] = self.refcounts.get(node_id, 0) + 1
def run_work(self, work_generators, ts=None):
"""run work_generator.do() recursively as needed
work_generators : list of generators (eg list( self.find_work() ))
who return objects with .do() methods that
either return None or other generators.
if a ttystatus.TerminalStatus instance is passed as ts,
report fsck progress via ts
"""
while work_generators:
work_generator = work_generators.pop(0)
for work in work_generator:
if ts:
ts.increase('items', 1)
ts['item'] = work
generator_or_none = work.do()
if generator_or_none:
# Run new work before carrying-on with work_generators
# (required for proper refcount check)
work_generators.insert(0,generator_or_none)
def run_fsck(self, ts=None):
"""Runs full fsck
if a ttystatus.TerminalStatus instance is passed as ts,
report fsck progress via ts item/items updates
"""
# Make sure that we pass list( self.find_work() ) and not
# [ self.find_work() ] so that when CheckForest.do() returns
# work generators, the work generators are actually called
# before the CheckRefcounts check.
work_generators = list( self.find_work() )
self.run_work(work_generators, ts=ts)
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