We are currently solving the following issue within our repository. Here is the issue text:
--- BEGIN ISSUE ---
Improve exception handling in FileSystemTimelineJob
Under certain conditions, dfvfs may throw exceptions that are not currently being handked:

```
dfvfs.lib.errors.BackEndError: Unable to open file system with error: pyfsext_volume_open_file_object: unable to open volume. libfsext_superblock_read_data: unsupported read-only compatible features flags: 0xff000003. libfsext_superblock_read_file_io_handle: unable to read superblock at offset: 1024 (0x00000400). libfsext_internal_volume_read_block_groups: unable to read superblock: 0 at offset: 1024 (0x00000400). libfsext_internal_volume_open_read: unable to read block groups. libfsext_volume_open_file_io_handle: unable to read from file IO handle.
```


--- END ISSUE ---

Below are some code segments, each from a relevant file. One or more of these files may contain bugs.
--- BEGIN FILES ---
Path: `turbinia/workers/file_system_timeline.py`
Content:
```
1 # -*- coding: utf-8 -*-
2 # Copyright 2022 Google Inc.
3 #
4 # Licensed under the Apache License, Version 2.0 (the "License");
5 # you may not use this file except in compliance with the License.
6 # You may obtain a copy of the License at
7 #
8 #      http://www.apache.org/licenses/LICENSE-2.0
9 #
10 # Unless required by applicable law or agreed to in writing, software
11 # distributed under the License is distributed on an "AS IS" BASIS,
12 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 # See the License for the specific language governing permissions and
14 # limitations under the License.
15 """Task to run dfimagetools FileEntryLister on disk partitions."""
16 
17 from __future__ import unicode_literals
18 
19 import os
20 
21 from turbinia import TurbiniaException
22 from turbinia.workers import TurbiniaTask
23 from turbinia.evidence import EvidenceState as state
24 from turbinia.evidence import BodyFile
25 
26 if TurbiniaTask.check_worker_role():
27   try:
28     from dfvfs.helpers import volume_scanner
29     from dfvfs.lib import errors as dfvfs_errors
30     from dfimagetools import file_entry_lister
31   except ImportError as exception:
32     message = 'Could not import libraries: {0!s}'.format(exception)
33     raise TurbiniaException(message)
34 
35 
36 class FileSystemTimelineTask(TurbiniaTask):
37 
38   REQUIRED_STATES = [state.ATTACHED]
39 
40   TASK_CONFIG = {'partitions': ['all']}
41 
42   def run(self, evidence, result):
43     """Task to execute (dfimagetools) FileEntryLister.
44 
45     Args:
46         evidence (Evidence object):  The evidence we will process.
47         result (TurbiniaTaskResult): The object to place task results into.
48 
49     Returns:
50         TurbiniaTaskResult object.
51     """
52     bodyfile_output = os.path.join(self.output_dir, 'file_system.bodyfile')
53     output_evidence = BodyFile(source_path=bodyfile_output)
54     number_of_entries = 0
55 
56     # Set things up for the FileEntryLister client. We will scan all
57     # partitions in the volume.
58     volume_scanner_options = volume_scanner.VolumeScannerOptions()
59     volume_scanner_options.partitions = self.task_config.get('partitions')
60 
61     # Create the FileEntryLister client and generate the path specs
62     # for all available partitions.
63     entry_lister = file_entry_lister.FileEntryLister()
64     base_path_specs = entry_lister.GetBasePathSpecs(
65         evidence.device_path, options=volume_scanner_options)
66 
67     # Iterate over all file entries and generate the output in bodyfile
68     # format.
69     try:
70       with open(bodyfile_output, 'w') as file_object:
71         for file_entry, path_segments in entry_lister.ListFileEntries(
72             base_path_specs):
73           bodyfile_entries = entry_lister.GetBodyfileEntries(
74               file_entry, path_segments)
75           for bodyfile_entry in bodyfile_entries:
76             file_object.write(bodyfile_entry)
77             file_object.write('\n')
78             number_of_entries += 1
79       output_evidence.number_of_entries = number_of_entries
80       result.add_evidence(output_evidence, evidence.config)
81       status = 'Generated file system timeline containing [{0:d}] entries'.format(
82           number_of_entries)
83       result.close(self, success=True, status=status)
84     except dfvfs_errors.ScannerError as exception:
85       result.log('Error generating bodyfile {0!s}'.format(exception))
86       status = 'Unable to generate bodyfile using provided evidence data.'
87       result.close(self, success=False, status=status)
88       raise TurbiniaException(
89           'Could not process volume: {0!s}'.format(exception))
90 
91     return result
92
```
--- END FILES ---

Please first localize the bug based on the issue statement, and then generate a patch according to the `git diff` format fenced by three backticks.

Here is an example:

```diff
diff --git a/examples/server_async.py b/examples/server_async.py
--- a/examples/server_async.py
+++ b/examples/server_async.py
@@ -313,4 +313,4 @@
 
 
 if __name__ == "__main__":
-    asyncio.run(run_async_server("."), debug=True)
+    asyncio.run(run_async_server(), debug=True)
diff --git a/examples/server_sync.py b/examples/server_sync.py
--- a/examples/server_sync.py
+++ b/examples/server_sync.py
@@ -313,5 +313,5 @@
 
 
 if __name__ == "__main__":
-    server = run_sync_server(".")
+    server = run_sync_server()
     server.shutdown()

```

diff --git a/turbinia/workers/file_system_timeline.py b/turbinia/workers/file_system_timeline.py
--- a/turbinia/workers/file_system_timeline.py
+++ b/turbinia/workers/file_system_timeline.py
@@ -34,6 +34,7 @@
 
 
 class FileSystemTimelineTask(TurbiniaTask):
+  """Task to generate file system timelines. """
 
   REQUIRED_STATES = [state.ATTACHED]
 
@@ -61,31 +62,49 @@
     # Create the FileEntryLister client and generate the path specs
     # for all available partitions.
     entry_lister = file_entry_lister.FileEntryLister()
-    base_path_specs = entry_lister.GetBasePathSpecs(
-        evidence.device_path, options=volume_scanner_options)
+    try:
+      base_path_specs = entry_lister.GetBasePathSpecs(
+          evidence.device_path, options=volume_scanner_options)
+    except dfvfs_errors.ScannerError as exception:
+      status = 'Unable to open evidence: {0!s}'.format(exception)
+      result.close(self, success=False, status=status)
 
     # Iterate over all file entries and generate the output in bodyfile
     # format.
     try:
-      with open(bodyfile_output, 'w') as file_object:
-        for file_entry, path_segments in entry_lister.ListFileEntries(
-            base_path_specs):
-          bodyfile_entries = entry_lister.GetBodyfileEntries(
-              file_entry, path_segments)
-          for bodyfile_entry in bodyfile_entries:
-            file_object.write(bodyfile_entry)
-            file_object.write('\n')
-            number_of_entries += 1
-      output_evidence.number_of_entries = number_of_entries
-      result.add_evidence(output_evidence, evidence.config)
-      status = 'Generated file system timeline containing [{0:d}] entries'.format(
-          number_of_entries)
-      result.close(self, success=True, status=status)
-    except dfvfs_errors.ScannerError as exception:
-      result.log('Error generating bodyfile {0!s}'.format(exception))
-      status = 'Unable to generate bodyfile using provided evidence data.'
+      file_entries = None
+      with open(bodyfile_output, 'w', encoding='utf-8') as file_object:
+        file_entries = enumerate(entry_lister.ListFileEntries(base_path_specs))
+        while file_entries:
+          try:
+            _, (file_entry, path_segments) = next(file_entries)
+            bodyfile_entries = entry_lister.GetBodyfileEntries(
+                file_entry, path_segments)
+            for bodyfile_entry in bodyfile_entries:
+              file_object.write(bodyfile_entry)
+              file_object.write('\n')
+              number_of_entries += 1
+          except StopIteration:
+            break
+          except (dfvfs_errors.AccessError, dfvfs_errors.BackEndError,
+                  dfvfs_errors.MountPointError,
+                  dfvfs_errors.PathSpecError) as exception:
+            status = 'Unable to process file entry: {0!s}'.format(exception)
+            result.log(status)
+
+      if number_of_entries > 0:
+        output_evidence.number_of_entries = number_of_entries
+        result.add_evidence(output_evidence, evidence.config)
+        status = 'Generated file system timeline containing [{0:d}] entries'.format(
+            number_of_entries)
+        result.close(self, success=True, status=status)
+      else:
+        status = 'Unable to process any file entries.'
+        result.close(self, success=False, status=status)
+
+    except IOError as exception:
+      status = 'Unable to create bodyfile local output file: {0!s}'.format(
+          exception)
       result.close(self, success=False, status=status)
-      raise TurbiniaException(
-          'Could not process volume: {0!s}'.format(exception))
 
     return result

{"golden_diff": "diff --git a/turbinia/workers/file_system_timeline.py b/turbinia/workers/file_system_timeline.py\n--- a/turbinia/workers/file_system_timeline.py\n+++ b/turbinia/workers/file_system_timeline.py\n@@ -34,6 +34,7 @@\n \n \n class FileSystemTimelineTask(TurbiniaTask):\n+  \"\"\"Task to generate file system timelines. \"\"\"\n \n   REQUIRED_STATES = [state.ATTACHED]\n \n@@ -61,31 +62,49 @@\n     # Create the FileEntryLister client and generate the path specs\n     # for all available partitions.\n     entry_lister = file_entry_lister.FileEntryLister()\n-    base_path_specs = entry_lister.GetBasePathSpecs(\n-        evidence.device_path, options=volume_scanner_options)\n+    try:\n+      base_path_specs = entry_lister.GetBasePathSpecs(\n+          evidence.device_path, options=volume_scanner_options)\n+    except dfvfs_errors.ScannerError as exception:\n+      status = 'Unable to open evidence: {0!s}'.format(exception)\n+      result.close(self, success=False, status=status)\n \n     # Iterate over all file entries and generate the output in bodyfile\n     # format.\n     try:\n-      with open(bodyfile_output, 'w') as file_object:\n-        for file_entry, path_segments in entry_lister.ListFileEntries(\n-            base_path_specs):\n-          bodyfile_entries = entry_lister.GetBodyfileEntries(\n-              file_entry, path_segments)\n-          for bodyfile_entry in bodyfile_entries:\n-            file_object.write(bodyfile_entry)\n-            file_object.write('\\n')\n-            number_of_entries += 1\n-      output_evidence.number_of_entries = number_of_entries\n-      result.add_evidence(output_evidence, evidence.config)\n-      status = 'Generated file system timeline containing [{0:d}] entries'.format(\n-          number_of_entries)\n-      result.close(self, success=True, status=status)\n-    except dfvfs_errors.ScannerError as exception:\n-      result.log('Error generating bodyfile {0!s}'.format(exception))\n-      status = 'Unable to generate bodyfile using provided evidence data.'\n+      file_entries = None\n+      with open(bodyfile_output, 'w', encoding='utf-8') as file_object:\n+        file_entries = enumerate(entry_lister.ListFileEntries(base_path_specs))\n+        while file_entries:\n+          try:\n+            _, (file_entry, path_segments) = next(file_entries)\n+            bodyfile_entries = entry_lister.GetBodyfileEntries(\n+                file_entry, path_segments)\n+            for bodyfile_entry in bodyfile_entries:\n+              file_object.write(bodyfile_entry)\n+              file_object.write('\\n')\n+              number_of_entries += 1\n+          except StopIteration:\n+            break\n+          except (dfvfs_errors.AccessError, dfvfs_errors.BackEndError,\n+                  dfvfs_errors.MountPointError,\n+                  dfvfs_errors.PathSpecError) as exception:\n+            status = 'Unable to process file entry: {0!s}'.format(exception)\n+            result.log(status)\n+\n+      if number_of_entries > 0:\n+        output_evidence.number_of_entries = number_of_entries\n+        result.add_evidence(output_evidence, evidence.config)\n+        status = 'Generated file system timeline containing [{0:d}] entries'.format(\n+            number_of_entries)\n+        result.close(self, success=True, status=status)\n+      else:\n+        status = 'Unable to process any file entries.'\n+        result.close(self, success=False, status=status)\n+\n+    except IOError as exception:\n+      status = 'Unable to create bodyfile local output file: {0!s}'.format(\n+          exception)\n       result.close(self, success=False, status=status)\n-      raise TurbiniaException(\n-          'Could not process volume: {0!s}'.format(exception))\n \n     return result\n", "issue": "Improve exception handling in FileSystemTimelineJob\nUnder certain conditions, dfvfs may throw exceptions that are not currently being handked:\r\n\r\n```\r\ndfvfs.lib.errors.BackEndError: Unable to open file system with error: pyfsext_volume_open_file_object: unable to open volume. libfsext_superblock_read_data: unsupported read-only compatible features flags: 0xff000003. libfsext_superblock_read_file_io_handle: unable to read superblock at offset: 1024 (0x00000400). libfsext_internal_volume_read_block_groups: unable to read superblock: 0 at offset: 1024 (0x00000400). libfsext_internal_volume_open_read: unable to read block groups. libfsext_volume_open_file_io_handle: unable to read from file IO handle.\r\n```\r\n\n", "before_files": [{"content": "# -*- coding: utf-8 -*-\n# Copyright 2022 Google Inc.\n#\n# Licensed under the Apache License, Version 2.0 (the \"License\");\n# you may not use this file except in compliance with the License.\n# You may obtain a copy of the License at\n#\n#      http://www.apache.org/licenses/LICENSE-2.0\n#\n# Unless required by applicable law or agreed to in writing, software\n# distributed under the License is distributed on an \"AS IS\" BASIS,\n# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n# See the License for the specific language governing permissions and\n# limitations under the License.\n\"\"\"Task to run dfimagetools FileEntryLister on disk partitions.\"\"\"\n\nfrom __future__ import unicode_literals\n\nimport os\n\nfrom turbinia import TurbiniaException\nfrom turbinia.workers import TurbiniaTask\nfrom turbinia.evidence import EvidenceState as state\nfrom turbinia.evidence import BodyFile\n\nif TurbiniaTask.check_worker_role():\n  try:\n    from dfvfs.helpers import volume_scanner\n    from dfvfs.lib import errors as dfvfs_errors\n    from dfimagetools import file_entry_lister\n  except ImportError as exception:\n    message = 'Could not import libraries: {0!s}'.format(exception)\n    raise TurbiniaException(message)\n\n\nclass FileSystemTimelineTask(TurbiniaTask):\n\n  REQUIRED_STATES = [state.ATTACHED]\n\n  TASK_CONFIG = {'partitions': ['all']}\n\n  def run(self, evidence, result):\n    \"\"\"Task to execute (dfimagetools) FileEntryLister.\n\n    Args:\n        evidence (Evidence object):  The evidence we will process.\n        result (TurbiniaTaskResult): The object to place task results into.\n\n    Returns:\n        TurbiniaTaskResult object.\n    \"\"\"\n    bodyfile_output = os.path.join(self.output_dir, 'file_system.bodyfile')\n    output_evidence = BodyFile(source_path=bodyfile_output)\n    number_of_entries = 0\n\n    # Set things up for the FileEntryLister client. We will scan all\n    # partitions in the volume.\n    volume_scanner_options = volume_scanner.VolumeScannerOptions()\n    volume_scanner_options.partitions = self.task_config.get('partitions')\n\n    # Create the FileEntryLister client and generate the path specs\n    # for all available partitions.\n    entry_lister = file_entry_lister.FileEntryLister()\n    base_path_specs = entry_lister.GetBasePathSpecs(\n        evidence.device_path, options=volume_scanner_options)\n\n    # Iterate over all file entries and generate the output in bodyfile\n    # format.\n    try:\n      with open(bodyfile_output, 'w') as file_object:\n        for file_entry, path_segments in entry_lister.ListFileEntries(\n            base_path_specs):\n          bodyfile_entries = entry_lister.GetBodyfileEntries(\n              file_entry, path_segments)\n          for bodyfile_entry in bodyfile_entries:\n            file_object.write(bodyfile_entry)\n            file_object.write('\\n')\n            number_of_entries += 1\n      output_evidence.number_of_entries = number_of_entries\n      result.add_evidence(output_evidence, evidence.config)\n      status = 'Generated file system timeline containing [{0:d}] entries'.format(\n          number_of_entries)\n      result.close(self, success=True, status=status)\n    except dfvfs_errors.ScannerError as exception:\n      result.log('Error generating bodyfile {0!s}'.format(exception))\n      status = 'Unable to generate bodyfile using provided evidence data.'\n      result.close(self, success=False, status=status)\n      raise TurbiniaException(\n          'Could not process volume: {0!s}'.format(exception))\n\n    return result\n", "path": "turbinia/workers/file_system_timeline.py"}], "after_files": [{"content": "# -*- coding: utf-8 -*-\n# Copyright 2022 Google Inc.\n#\n# Licensed under the Apache License, Version 2.0 (the \"License\");\n# you may not use this file except in compliance with the License.\n# You may obtain a copy of the License at\n#\n#      http://www.apache.org/licenses/LICENSE-2.0\n#\n# Unless required by applicable law or agreed to in writing, software\n# distributed under the License is distributed on an \"AS IS\" BASIS,\n# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n# See the License for the specific language governing permissions and\n# limitations under the License.\n\"\"\"Task to run dfimagetools FileEntryLister on disk partitions.\"\"\"\n\nfrom __future__ import unicode_literals\n\nimport os\n\nfrom turbinia import TurbiniaException\nfrom turbinia.workers import TurbiniaTask\nfrom turbinia.evidence import EvidenceState as state\nfrom turbinia.evidence import BodyFile\n\nif TurbiniaTask.check_worker_role():\n  try:\n    from dfvfs.helpers import volume_scanner\n    from dfvfs.lib import errors as dfvfs_errors\n    from dfimagetools import file_entry_lister\n  except ImportError as exception:\n    message = 'Could not import libraries: {0!s}'.format(exception)\n    raise TurbiniaException(message)\n\n\nclass FileSystemTimelineTask(TurbiniaTask):\n  \"\"\"Task to generate file system timelines. \"\"\"\n\n  REQUIRED_STATES = [state.ATTACHED]\n\n  TASK_CONFIG = {'partitions': ['all']}\n\n  def run(self, evidence, result):\n    \"\"\"Task to execute (dfimagetools) FileEntryLister.\n\n    Args:\n        evidence (Evidence object):  The evidence we will process.\n        result (TurbiniaTaskResult): The object to place task results into.\n\n    Returns:\n        TurbiniaTaskResult object.\n    \"\"\"\n    bodyfile_output = os.path.join(self.output_dir, 'file_system.bodyfile')\n    output_evidence = BodyFile(source_path=bodyfile_output)\n    number_of_entries = 0\n\n    # Set things up for the FileEntryLister client. We will scan all\n    # partitions in the volume.\n    volume_scanner_options = volume_scanner.VolumeScannerOptions()\n    volume_scanner_options.partitions = self.task_config.get('partitions')\n\n    # Create the FileEntryLister client and generate the path specs\n    # for all available partitions.\n    entry_lister = file_entry_lister.FileEntryLister()\n    try:\n      base_path_specs = entry_lister.GetBasePathSpecs(\n          evidence.device_path, options=volume_scanner_options)\n    except dfvfs_errors.ScannerError as exception:\n      status = 'Unable to open evidence: {0!s}'.format(exception)\n      result.close(self, success=False, status=status)\n\n    # Iterate over all file entries and generate the output in bodyfile\n    # format.\n    try:\n      file_entries = None\n      with open(bodyfile_output, 'w', encoding='utf-8') as file_object:\n        file_entries = enumerate(entry_lister.ListFileEntries(base_path_specs))\n        while file_entries:\n          try:\n            _, (file_entry, path_segments) = next(file_entries)\n            bodyfile_entries = entry_lister.GetBodyfileEntries(\n                file_entry, path_segments)\n            for bodyfile_entry in bodyfile_entries:\n              file_object.write(bodyfile_entry)\n              file_object.write('\\n')\n              number_of_entries += 1\n          except StopIteration:\n            break\n          except (dfvfs_errors.AccessError, dfvfs_errors.BackEndError,\n                  dfvfs_errors.MountPointError,\n                  dfvfs_errors.PathSpecError) as exception:\n            status = 'Unable to process file entry: {0!s}'.format(exception)\n            result.log(status)\n\n      if number_of_entries > 0:\n        output_evidence.number_of_entries = number_of_entries\n        result.add_evidence(output_evidence, evidence.config)\n        status = 'Generated file system timeline containing [{0:d}] entries'.format(\n            number_of_entries)\n        result.close(self, success=True, status=status)\n      else:\n        status = 'Unable to process any file entries.'\n        result.close(self, success=False, status=status)\n\n    except IOError as exception:\n      status = 'Unable to create bodyfile local output file: {0!s}'.format(\n          exception)\n      result.close(self, success=False, status=status)\n\n    return result\n", "path": "turbinia/workers/file_system_timeline.py"}]}