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use DeferredLock instead of threading.Lock() as it can cause deadlocks

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Kay Kurokawa 2017-10-06 17:05:10 -04:00
parent 2115919c55
commit d9cc81766d
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GPG key ID: 2D65FB1698958B8D
2 changed files with 18 additions and 15 deletions
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29
lbrynet/blob/blob_file.py
View file

@ -1,6 +1,5 @@
import logging
import os
import threading
from twisted.internet import defer, threads
from twisted.protocols.basic import FileSender
from twisted.web.client import FileBodyProducer
@ -40,7 +39,7 @@ class BlobFile(object):
self.readers = 0
self.blob_dir = blob_dir
self.file_path = os.path.join(blob_dir, self.blob_hash)
self.setting_verified_blob_lock = threading.Lock()
self.blob_write_lock = defer.DeferredLock()
self.moved_verified_blob = False
if os.path.isfile(self.file_path):
self.set_length(os.path.getsize(self.file_path))
@ -201,7 +200,7 @@ class BlobFile(object):
if err is None:
if writer.len_so_far == self.length and writer.blob_hash == self.blob_hash:
if self._verified is False:
d = self._save_verified_blob(writer)
d = self.save_verified_blob(writer)
d.addCallbacks(lambda _: fire_finished_deferred(), errback_finished_deferred)
d.addCallback(lambda _: cancel_other_downloads())
else:
@ -219,15 +218,19 @@ class BlobFile(object):
d.addBoth(lambda _: writer.close_handle())
return d
def save_verified_blob(self, writer):
# we cannot have multiple _save_verified_blob interrupting
# each other, can happen since startProducing is a deferred
return self.blob_write_lock.run(self._save_verified_blob, writer)
@defer.inlineCallbacks
def _save_verified_blob(self, writer):
with self.setting_verified_blob_lock:
if self.moved_verified_blob is False:
writer.write_handle.seek(0)
out_path = os.path.join(self.blob_dir, self.blob_hash)
producer = FileBodyProducer(writer.write_handle)
yield producer.startProducing(open(out_path, 'wb'))
self.moved_verified_blob = True
defer.returnValue(True)
else:
raise DownloadCanceledError()
if self.moved_verified_blob is False:
writer.write_handle.seek(0)
out_path = os.path.join(self.blob_dir, self.blob_hash)
producer = FileBodyProducer(writer.write_handle)
yield producer.startProducing(open(out_path, 'wb'))
self.moved_verified_blob = True
defer.returnValue(True)
else:
raise DownloadCanceledError()

4
lbrynet/tests/unit/core/test_HashBlob.py
View file

@ -150,7 +150,7 @@ class BlobFileTest(unittest.TestCase):
writer_1, finished_d_1 = blob_file.open_for_writing(peer=1)
writer_2, finished_d_2 = blob_file.open_for_writing(peer=2)
blob_file._save_verified_blob(writer_1)
blob_file.save_verified_blob(writer_1)
# second write should fail to save
yield self.assertFailure(blob_file._save_verified_blob(writer_2), DownloadCanceledError)
yield self.assertFailure(blob_file.save_verified_blob(writer_2), DownloadCanceledError)