bucket_counter.state and lease_checker.state might get corrupted after hard system shutdown

[francois]

After a hard system shutdown due to power failure, Tahoe node might not be able to start again automatically because files storage/bucket_counter.state or storage/lease_checker.state are empty.

The easy workaround is to manually delete the empty files before restarting nodes.

find /srv/tahoe/*/storage/bucket_counter.state -size 0 -exec rm {} \;
find /srv/tahoe/*/storage/lease_checker.state -size 0 -exec rm {} \;

Here is what a startup attempt looks like in such case.

Traceback (most recent call last):
  File "/usr/lib/python2.5/site-packages/twisted/application/app.py", line 614, in run
    runApp(config)
  File "/usr/lib/python2.5/site-packages/twisted/scripts/twistd.py", line 23, in runApp
    _SomeApplicationRunner(config).run()
  File "/usr/lib/python2.5/site-packages/twisted/application/app.py", line 330, in run
    self.application = self.createOrGetApplication()
  File "/usr/lib/python2.5/site-packages/twisted/application/app.py", line 416, in createOrGetApplication
    application = getApplication(self.config, passphrase)
--- <exception caught here> ---
  File "/usr/lib/python2.5/site-packages/twisted/application/app.py", line 427, in getApplication
    application = service.loadApplication(filename, style, passphrase)
  File "/usr/lib/python2.5/site-packages/twisted/application/service.py", line 368, in loadApplication
    application = sob.loadValueFromFile(filename, 'application', passphrase)
  File "/usr/lib/python2.5/site-packages/twisted/persisted/sob.py", line 214, in loadValueFromFile
    exec fileObj in d, d
  File "tahoe-client.tac", line 10, in <module>
    c = client.Client()
  File "/opt/tahoe-lafs/src/allmydata/client.py", line 140, in __init__
    self.init_storage()
  File "/opt/tahoe-lafs/src/allmydata/client.py", line 269, in init_storage
    expiration_sharetypes=expiration_sharetypes)
  File "/opt/tahoe-lafs/src/allmydata/storage/server.py", line 97, in __init__
    self.add_bucket_counter()
  File "/opt/tahoe-lafs/src/allmydata/storage/server.py", line 114, in add_bucket_counter
    self.bucket_counter = BucketCountingCrawler(self, statefile)
  File "/opt/tahoe-lafs/src/allmydata/storage/crawler.py", line 449, in __init__
    ShareCrawler.__init__(self, server, statefile)
  File "/opt/tahoe-lafs/src/allmydata/storage/crawler.py", line 86, in __init__
    self.load_state()
  File "/opt/tahoe-lafs/src/allmydata/storage/crawler.py", line 195, in load_state
    state = pickle.load(f)
exceptions.EOFError: