def delete_some_dummy_chunks(self, how_many, dummy_chunk_uuids=None):
"""
Delete some dummy chunks (from FS and from DB).
Yields the UUIDs of dummy chunks after removing of each one.
@param how_many: How many dummy chunks to delete.
@type how_many: numbers.Integral
@param dummy_chunk_uuids: (Optional) set of the dummy chunk UUIDs
(if we know it already).
If None, calculated automatically.
@type dummy_chunk_uuids: (set, NoneType)
"""
# For clarity only
super(ChunkStorageFS, self).delete_some_dummy_chunks(how_many,
dummy_chunk_uuids)
with self.__chunk_op_lock:
_dummy_chunk_uuids_iter = \
self.__get_dummy_chunk_uuids_on_fs() \
if dummy_chunk_uuids is None \
else dummy_chunk_uuids
# list needed so it can be used three times
removing_dummy_chunks = list(take(how_many,
_dummy_chunk_uuids_iter))
# not "how_many", but len(removing_dummy_chunks), cause
# we may probably remove less than required.
logger.debug('Removing %i dummy chunks',
len(removing_dummy_chunks))
for dummy_chunk_uuid in removing_dummy_chunks:
try:
_path = self.__get_chunk_file_path(dummy_chunk_uuid,
is_dummy=True)
os.unlink(_path)
except Exception as e:
logger.exception('Problem during removing chunk %s: %r',
dummy_chunk_uuid, e)
yield dummy_chunk_uuid # even if failed
logger.debug('Deleted dummy chunk %r', dummy_chunk_uuid)
HostQueries.HostChunks.delete_dummy_chunks(removing_dummy_chunks)
def update_dummy_chunks_size(self,
old_limit_mib=None, new_limit_mib=None):
"""
Whenever the situation with the chunks could have been changed,
update the dummy chunks: create new ones if there is a lack of them,
or remove unneeded ones if there is an excess of them.
@param old_limit_mib: The previous total amount of chunks to keep
in storage, assumed 0 if None.
@type old_limit_mib: numbers.Integral, NoneType
@param new_limit_mib: The new total amount of chunks to keep
in storage, taken from the settings if None.
@type new_limit_mib: numbers.Integral, NoneType
"""
# For clarity only
super(ChunkStorageFS, self).update_dummy_chunks_size(old_limit_mib,
new_limit_mib)
# TODO! TODO! TODO! we don't bother with dummy chunks for now
logger.warn('update_dummy_chunks_size() disabled')
return
if new_limit_mib is None:
assert old_limit_mib is None
new_limit_mib = \
HostQueries.HostSettings.get(Queries.Settings
.MAX_STORAGE_SIZE_MIB)
# This two variables will be used to specify the progress of the task.
num, of = 0, 0
_operation = '<generic operation>'
@exceptions_logged(logger)
def timercb():
"""
Callback function called on timer firing.
"""
if (num, of) != (0, 0):
logger_status_chunks_op.info(
'The chunk reallocation takes too long, completed %i/%i',
num, of,
extra={'_type': 'chunks_allocation.progress',
'num': num,
'of': of})
timer_service = TimerService(1.0, timercb)
# If the task takes more than 3 seconds,
# start notifying about the progress
_callLater = reactor.callLater # pylint:disable=E1101,C0103
# Won't worry about deferToThread here, cause it is very fast.
long_task_timer = _callLater(3.0, timer_service.startService)
logger.debug('Resizing dummy chunk set from %s to %s',
old_limit_mib, new_limit_mib)
with self.__chunk_op_lock:
try:
# Check for dummy chunks before the check for present files,
# as the check for dummy chunks also may remove some
# of the files.
# What dummy chunks are available?
# list, so it can be used twice.
# TODO: do we need to use it twice?
dummy_chunk_uuids = list(self.__get_dummy_chunk_uuids_on_fs())
how_many_dummy_chunks = len(dummy_chunk_uuids)
# What chunk files are present on the FS,...
present_chunk_filenames_iter = \
self.__get_chunk_filenames_on_fs(self.__chunk_dir)
# ... and what are the chunk UUIDs?
# present_chunk_uuids = \
# self.__class__.convert_chunk_filenames_to_uuids(
# present_chunk_filenames)
# How many bytes/MiB do we need to have preallocated?
reserved_mib = long(new_limit_mib)
reserved_size = reserved_mib * 0x100000
# How many bytes/MiB is preallocated already?
present_chunk_size = \
sum(os.stat(f).st_size
for f in present_chunk_filenames_iter)
del present_chunk_filenames_iter # help GC
present_chunks_in_mib = \
round_up_to_multiply(present_chunk_size,
0x100000) // 0x100000
if reserved_mib > present_chunks_in_mib:
# Add new chunks
how_many_new_chunks = reserved_mib - present_chunks_in_mib
of = how_many_new_chunks
_operation = 'allocation'
for u in self.__create_some_dummy_chunks(
how_many_new_chunks):
num += 1
elif reserved_mib < present_chunks_in_mib:
# Try to remove some dummy chunks...
how_many_chunks_try_to_remove = \
present_chunks_in_mib - reserved_mib
# But we cannot remove more than len(dummy_chunk_uuids)!
if how_many_dummy_chunks < how_many_chunks_try_to_remove:
logger.debug('Trying to remove %i chunks, '
'but only %i dummy chunks available!',
how_many_chunks_try_to_remove,
how_many_dummy_chunks)
how_many_chunks_to_remove = \
min(how_many_chunks_try_to_remove,
how_many_dummy_chunks)
of = how_many_chunks_to_remove
_operation = 'removing'
chunk_uuids_to_delete = take(how_many_chunks_to_remove,
dummy_chunk_uuids)
for u in self.delete_some_dummy_chunks(
how_many_chunks_to_remove,
chunk_uuids_to_delete):
num += 1
except Exception as e:
logger_status_chunks_op_error.error(
'The chunk %s failed: %r',
_operation, e,
extra={'_type': 'chunks_allocation.error',
'_exc': e,
'_tb': traceback.format_exc()})
finally:
# We've done with the chunks allocation.
# Now stop the timer, and manually report that 100%
# of the work is done.
if (not long_task_timer.called and
not long_task_timer.cancelled):
long_task_timer.cancel()
if timer_service.running:
timer_service.stopService()
timercb()
