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<div class="document">
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 <div class="section" id="example-file-systems">
<h1>Example File Systems<a class="headerlink" href="#example-file-systems" title="Permalink to this headline">¶</a></h1>
Python-LLFUSE comes with several example file systems in the
<code class="file docutils literal notranslate">examples</code> directory of the release tarball. For completeness,
these examples are also included here.
<div class="section" id="single-file-read-only-file-system">
<h2>Single-file, Read-only File System<a class="headerlink" href="#single-file-read-only-file-system" title="Permalink to this headline">¶</a></h2>
(shipped as <code class="file docutils literal notranslate">examples/lltest.py</code>)
<div class="highlight-python notranslate"><table class="highlighttable"><tr><td class="linenos"><div class="linenodiv"><pre> 1
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155</pre></div></td><td class="code"><div class="highlight"><pre>#!/usr/bin/env python3
&#39;&#39;&#39;
lltest.py - Example file system for Python-LLFUSE.

This program presents a static file system containing a single file. It is
compatible with both Python 2.x and 3.x. Based on an example from Gerion Entrup.

Permission is hereby granted, free of charge, to any person obtaining a copy of
this software and associated documentation files (the &quot;Software&quot;), to deal in
the Software without restriction, including without limitation the rights to
use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
the Software, and to permit persons to whom the Software is furnished to do so.

THE SOFTWARE IS PROVIDED &quot;AS IS&quot;, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
&#39;&#39;&#39;

import os
import sys

# If we are running from the Python-LLFUSE source directory, try
# to load the module from there first.
basedir = os.path.abspath(os.path.join(os.path.dirname(sys.argv[0]), &#39;..&#39;))
if (os.path.exists(os.path.join(basedir, &#39;setup.py&#39;)) and
 os.path.exists(os.path.join(basedir, &#39;src&#39;, &#39;llfuse.pyx&#39;))):
 sys.path.insert(0, os.path.join(basedir, &#39;src&#39;))

from argparse import ArgumentParser
import stat
import logging
import errno
import llfuse

try:
 import faulthandler
except ImportError:
 pass
else:
 faulthandler.enable()

log = logging.getLogger(__name__)

class TestFs(llfuse.Operations):
 def __init__(self):
 super().__init__()
 self.hello_name = b&quot;message&quot;
 self.hello_inode = llfuse.ROOT_INODE+1
 self.hello_data = b&quot;hello world\n&quot;

def getattr(self, inode, ctx=None):
 entry = llfuse.EntryAttributes()
 if inode == llfuse.ROOT_INODE:
 entry.st_mode = (stat.S_IFDIR | 0o755)
 entry.st_size = 0
 elif inode == self.hello_inode:
 entry.st_mode = (stat.S_IFREG | 0o644)
 entry.st_size = len(self.hello_data)
 else:
 raise llfuse.FUSEError(errno.ENOENT)

stamp = int(1438467123.985654 * 1e9)
 entry.st_atime_ns = stamp
 entry.st_ctime_ns = stamp
 entry.st_mtime_ns = stamp
 entry.st_gid = os.getgid()
 entry.st_uid = os.getuid()
 entry.st_ino = inode

return entry

def lookup(self, parent_inode, name, ctx=None):
 if parent_inode != llfuse.ROOT_INODE or name != self.hello_name:
 raise llfuse.FUSEError(errno.ENOENT)
 return self.getattr(self.hello_inode)

def opendir(self, inode, ctx):
 if inode != llfuse.ROOT_INODE:
 raise llfuse.FUSEError(errno.ENOENT)
 return inode

def readdir(self, fh, off):
 assert fh == llfuse.ROOT_INODE

# only one entry
 if off == 0:
 yield (self.hello_name, self.getattr(self.hello_inode), 1)

def init_logging(debug=False):
 formatter = logging.Formatter(&#39;%(asctime)s.%(msecs)03d %(threadName)s: &#39;
 &#39;[%(name)s] %(message)s&#39;, datefmt=&quot;%Y-%m-%d %H:%M:%S&quot;)
 handler = logging.StreamHandler()
 handler.setFormatter(formatter)
 root_logger = logging.getLogger()
 if debug:
 handler.setLevel(logging.DEBUG)
 root_logger.setLevel(logging.DEBUG)
 else:
 handler.setLevel(logging.INFO)
 root_logger.setLevel(logging.INFO)
 root_logger.addHandler(handler)

def parse_args():
 &#39;&#39;&#39;Parse command line&#39;&#39;&#39;

parser = ArgumentParser()

parser.add_argument(&#39;mountpoint&#39;, type=str,
 help=&#39;Where to mount the file system&#39;)
 parser.add_argument(&#39;--debug&#39;, action=&#39;store_true&#39;, default=False,
 help=&#39;Enable debugging output&#39;)
 parser.add_argument(&#39;--debug-fuse&#39;, action=&#39;store_true&#39;, default=False,
 help=&#39;Enable FUSE debugging output&#39;)
 return parser.parse_args()

testfs = TestFs()
 fuse_options = set(llfuse.default_options)
 fuse_options.add(&#39;fsname=lltest&#39;)
 if options.debug_fuse:
 fuse_options.add(&#39;debug&#39;)
 llfuse.init(testfs, options.mountpoint, fuse_options)
 try:
 llfuse.main(workers=1)
 except:
 llfuse.close(unmount=False)
 raise

llfuse.close()

if __name__ == &#39;__main__&#39;:
 main()
</pre></div>
</td></tr></table></div>
</div>
<div class="section" id="in-memory-file-system">
<h2>In-memory File System<a class="headerlink" href="#in-memory-file-system" title="Permalink to this headline">¶</a></h2>
(shipped as <code class="file docutils literal notranslate">examples/tmpfs.py</code>)
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&#39;&#39;&#39;
tmpfs.py - Example file system for Python-LLFUSE.

This file system stores all data in memory. It is compatible with both Python
2.x and 3.x.

import os
import sys

import llfuse
import errno
import stat
from time import time
import sqlite3
import logging
from collections import defaultdict
from llfuse import FUSEError
from argparse import ArgumentParser

log = logging.getLogger()

class Operations(llfuse.Operations):
 &#39;&#39;&#39;An example filesystem that stores all data in memory

This is a very simple implementation with terrible performance.
 Don&#39;t try to store significant amounts of data. Also, there are
 some other flaws that have not been fixed to keep the code easier
 to understand:

* atime, mtime and ctime are not updated
 * generation numbers are not supported
 &#39;&#39;&#39;

def __init__(self):
 super().__init__()
 self.db = sqlite3.connect(&#39;:memory:&#39;)
 self.db.text_factory = str
 self.db.row_factory = sqlite3.Row
 self.cursor = self.db.cursor()
 self.inode_open_count = defaultdict(int)
 self.init_tables()

def init_tables(self):
 &#39;&#39;&#39;Initialize file system tables&#39;&#39;&#39;

self.cursor.execute(&quot;&quot;&quot;
 CREATE TABLE inodes (
 id INTEGER PRIMARY KEY,
 uid INT NOT NULL,
 gid INT NOT NULL,
 mode INT NOT NULL,
 mtime_ns INT NOT NULL,
 atime_ns INT NOT NULL,
 ctime_ns INT NOT NULL,
 target BLOB(256) ,
 size INT NOT NULL DEFAULT 0,
 rdev INT NOT NULL DEFAULT 0,
 data BLOB
 )
 &quot;&quot;&quot;)

UNIQUE (name, parent_inode)
 )&quot;&quot;&quot;)

# Insert root directory
 now_ns = int(time() * 1e9)
 self.cursor.execute(&quot;INSERT INTO inodes (id,mode,uid,gid,mtime_ns,atime_ns,ctime_ns) &quot;
 &quot;VALUES (?,?,?,?,?,?,?)&quot;,
 (llfuse.ROOT_INODE, stat.S_IFDIR | stat.S_IRUSR | stat.S_IWUSR
 | stat.S_IXUSR | stat.S_IRGRP | stat.S_IXGRP | stat.S_IROTH
 | stat.S_IXOTH, os.getuid(), os.getgid(), now_ns, now_ns, now_ns))
 self.cursor.execute(&quot;INSERT INTO contents (name, parent_inode, inode) VALUES (?,?,?)&quot;,
 (b&#39;..&#39;, llfuse.ROOT_INODE, llfuse.ROOT_INODE))

def get_row(self, *a, **kw):
 self.cursor.execute(*a, **kw)
 try:
 row = next(self.cursor)
 except StopIteration:
 raise NoSuchRowError()
 try:
 next(self.cursor)
 except StopIteration:
 pass
 else:
 raise NoUniqueValueError()

return row

def lookup(self, inode_p, name, ctx=None):
 if name == &#39;.&#39;:
 inode = inode_p
 elif name == &#39;..&#39;:
 inode = self.get_row(&quot;SELECT * FROM contents WHERE inode=?&quot;,
 (inode_p,))[&#39;parent_inode&#39;]
 else:
 try:
 inode = self.get_row(&quot;SELECT * FROM contents WHERE name=? AND parent_inode=?&quot;,
 (name, inode_p))[&#39;inode&#39;]
 except NoSuchRowError:
 raise(llfuse.FUSEError(errno.ENOENT))

return self.getattr(inode, ctx)

entry = llfuse.EntryAttributes()
 entry.st_ino = inode
 entry.generation = 0
 entry.entry_timeout = 300
 entry.attr_timeout = 300
 entry.st_mode = row[&#39;mode&#39;]
 entry.st_nlink = self.get_row(&quot;SELECT COUNT(inode) FROM contents WHERE inode=?&quot;,
 (inode,))[0]
 entry.st_uid = row[&#39;uid&#39;]
 entry.st_gid = row[&#39;gid&#39;]
 entry.st_rdev = row[&#39;rdev&#39;]
 entry.st_size = row[&#39;size&#39;]

entry.st_blksize = 512
 entry.st_blocks = 1
 entry.st_atime_ns = row[&#39;atime_ns&#39;]
 entry.st_mtime_ns = row[&#39;mtime_ns&#39;]
 entry.st_ctime_ns = row[&#39;ctime_ns&#39;]

return entry

cursor2 = self.db.cursor()
 cursor2.execute(&quot;SELECT * FROM contents WHERE parent_inode=? &quot;
 &#39;AND rowid &gt; ? ORDER BY rowid&#39;, (inode, off))

for row in cursor2:
 yield (row[&#39;name&#39;], self.getattr(row[&#39;inode&#39;]), row[&#39;rowid&#39;])

if stat.S_ISDIR(entry.st_mode):
 raise llfuse.FUSEError(errno.EISDIR)

self._remove(inode_p, name, entry)

if not stat.S_ISDIR(entry.st_mode):
 raise llfuse.FUSEError(errno.ENOTDIR)

def _remove(self, inode_p, name, entry):
 if self.get_row(&quot;SELECT COUNT(inode) FROM contents WHERE parent_inode=?&quot;,
 (entry.st_ino,))[0] &gt; 0:
 raise llfuse.FUSEError(errno.ENOTEMPTY)

self.cursor.execute(&quot;DELETE FROM contents WHERE name=? AND parent_inode=?&quot;,
 (name, inode_p))

if entry.st_nlink == 1 and entry.st_ino not in self.inode_open_count:
 self.cursor.execute(&quot;DELETE FROM inodes WHERE id=?&quot;, (entry.st_ino,))

try:
 entry_new = self.lookup(inode_p_new, name_new)
 except llfuse.FUSEError as exc:
 if exc.errno != errno.ENOENT:
 raise
 target_exists = False
 else:
 target_exists = True

if target_exists:
 self._replace(inode_p_old, name_old, inode_p_new, name_new,
 entry_old, entry_new)
 else:
 self.cursor.execute(&quot;UPDATE contents SET name=?, parent_inode=? WHERE name=? &quot;
 &quot;AND parent_inode=?&quot;, (name_new, inode_p_new,
 name_old, inode_p_old))

def _replace(self, inode_p_old, name_old, inode_p_new, name_new,
 entry_old, entry_new):

if self.get_row(&quot;SELECT COUNT(inode) FROM contents WHERE parent_inode=?&quot;,
 (entry_new.st_ino,))[0] &gt; 0:
 raise llfuse.FUSEError(errno.ENOTEMPTY)

self.cursor.execute(&quot;UPDATE contents SET inode=? WHERE name=? AND parent_inode=?&quot;,
 (entry_old.st_ino, name_new, inode_p_new))
 self.db.execute(&#39;DELETE FROM contents WHERE name=? AND parent_inode=?&#39;,
 (name_old, inode_p_old))

if entry_new.st_nlink == 1 and entry_new.st_ino not in self.inode_open_count:
 self.cursor.execute(&quot;DELETE FROM inodes WHERE id=?&quot;, (entry_new.st_ino,))

self.cursor.execute(&quot;INSERT INTO contents (name, inode, parent_inode) VALUES(?,?,?)&quot;,
 (new_name, inode, new_inode_p))

return self.getattr(inode)

if fields.update_size:
 data = self.get_row(&#39;SELECT data FROM inodes WHERE id=?&#39;, (inode,))[0]
 if data is None:
 data = b&#39;&#39;
 if len(data) &lt; attr.st_size:
 data = data + b&#39;\0&#39; * (attr.st_size - len(data))
 else:
 data = data[:attr.st_size]
 self.cursor.execute(&#39;UPDATE inodes SET data=?, size=? WHERE id=?&#39;,
 (memoryview(data), attr.st_size, inode))
 if fields.update_mode:
 self.cursor.execute(&#39;UPDATE inodes SET mode=? WHERE id=?&#39;,
 (attr.st_mode, inode))

if fields.update_uid:
 self.cursor.execute(&#39;UPDATE inodes SET uid=? WHERE id=?&#39;,
 (attr.st_uid, inode))

if fields.update_gid:
 self.cursor.execute(&#39;UPDATE inodes SET gid=? WHERE id=?&#39;,
 (attr.st_gid, inode))

if fields.update_atime:
 self.cursor.execute(&#39;UPDATE inodes SET atime_ns=? WHERE id=?&#39;,
 (attr.st_atime_ns, inode))

if fields.update_mtime:
 self.cursor.execute(&#39;UPDATE inodes SET mtime_ns=? WHERE id=?&#39;,
 (attr.st_mtime_ns, inode))

return self.getattr(inode)

stat_.f_bsize = 512
 stat_.f_frsize = 512

size = self.get_row(&#39;SELECT SUM(size) FROM inodes&#39;)[0]
 stat_.f_blocks = size // stat_.f_frsize
 stat_.f_bfree = max(size // stat_.f_frsize, 1024)
 stat_.f_bavail = stat_.f_bfree

inodes = self.get_row(&#39;SELECT COUNT(id) FROM inodes&#39;)[0]
 stat_.f_files = inodes
 stat_.f_ffree = max(inodes , 100)
 stat_.f_favail = stat_.f_ffree

return stat_

# Use inodes as a file handles
 return inode

def access(self, inode, mode, ctx):
 # Yeah, could be a function and has unused arguments
 #pylint: disable=R0201,W0613
 return True

def create(self, inode_parent, name, mode, flags, ctx):
 #pylint: disable=W0612
 entry = self._create(inode_parent, name, mode, ctx)
 self.inode_open_count[entry.st_ino] += 1
 return (entry.st_ino, entry)

def _create(self, inode_p, name, mode, ctx, rdev=0, target=None):
 if self.getattr(inode_p).st_nlink == 0:
 log.warn(&#39;Attempted to create entry %s with unlinked parent %d&#39;,
 name, inode_p)
 raise FUSEError(errno.EINVAL)

now_ns = int(time() * 1e9)
 self.cursor.execute(&#39;INSERT INTO inodes (uid, gid, mode, mtime_ns, atime_ns, &#39;
 &#39;ctime_ns, target, rdev) VALUES(?, ?, ?, ?, ?, ?, ?, ?)&#39;,
 (ctx.uid, ctx.gid, mode, now_ns, now_ns, now_ns, target, rdev))

inode = self.cursor.lastrowid
 self.db.execute(&quot;INSERT INTO contents(name, inode, parent_inode) VALUES(?,?,?)&quot;,
 (name, inode, inode_p))
 return self.getattr(inode)

def read(self, fh, offset, length):
 data = self.get_row(&#39;SELECT data FROM inodes WHERE id=?&#39;, (fh,))[0]
 if data is None:
 data = b&#39;&#39;
 return data[offset:offset+length]

def write(self, fh, offset, buf):
 data = self.get_row(&#39;SELECT data FROM inodes WHERE id=?&#39;, (fh,))[0]
 if data is None:
 data = b&#39;&#39;
 data = data[:offset] + buf + data[offset+len(buf):]

self.cursor.execute(&#39;UPDATE inodes SET data=?, size=? WHERE id=?&#39;,
 (memoryview(data), len(data), fh))
 return len(buf)

def release(self, fh):
 self.inode_open_count[fh] -= 1

if self.inode_open_count[fh] == 0:
 del self.inode_open_count[fh]
 if self.getattr(fh).st_nlink == 0:
 self.cursor.execute(&quot;DELETE FROM inodes WHERE id=?&quot;, (fh,))

class NoUniqueValueError(Exception):
 def __str__(self):
 return &#39;Query generated more than 1 result row&#39;

class NoSuchRowError(Exception):
 def __str__(self):
 return &#39;Query produced 0 result rows&#39;

def parse_args():
 &#39;&#39;&#39;Parse command line&#39;&#39;&#39;

parser = ArgumentParser()

return parser.parse_args()

if __name__ == &#39;__main__&#39;:

options = parse_args()
 init_logging(options.debug)
 operations = Operations()

fuse_options = set(llfuse.default_options)
 fuse_options.add(&#39;fsname=tmpfs&#39;)
 fuse_options.discard(&#39;default_permissions&#39;)
 if options.debug_fuse:
 fuse_options.add(&#39;debug&#39;)
 llfuse.init(operations, options.mountpoint, fuse_options)

# sqlite3 does not support multithreading
 try:
 llfuse.main(workers=1)
 except:
 llfuse.close(unmount=False)
 raise

llfuse.close()
</pre></div>
</td></tr></table></div>
</div>
<div class="section" id="passthrough-overlay-file-system">
<h2>Passthrough / Overlay File System<a class="headerlink" href="#passthrough-overlay-file-system" title="Permalink to this headline">¶</a></h2>
(shipped as <code class="file docutils literal notranslate">examples/passthroughfs.py</code>)
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470</pre></div></td><td class="code"><div class="highlight"><pre>#!/usr/bin/env python3
&#39;&#39;&#39;
passthroughfs.py - Example file system for Python-LLFUSE

This file system mirrors the contents of a specified directory tree. It requires
Python 3.3 (since Python 2.x does not support the follow_symlinks parameters for
os.* functions).

Caveats:

* Inode generation numbers are not passed through but set to zero.

* Block size (st_blksize) and number of allocated blocks (st_blocks) are not
 passed through.

* Performance for large directories is not good, because the directory
 is always read completely.

* There may be a way to break-out of the directory tree.

* The readdir implementation is not fully POSIX compliant. If a directory
 contains hardlinks and is modified during a readdir call, readdir()
 may return some of the hardlinked files twice or omit them completely.

* If you delete or rename files in the underlying file system, the
 passthrough file system will get confused.

import os
import sys

import llfuse
from argparse import ArgumentParser
import errno
import logging
import stat as stat_m
from llfuse import FUSEError
from os import fsencode, fsdecode
from collections import defaultdict

import faulthandler
faulthandler.enable()

class Operations(llfuse.Operations):

def __init__(self, source):
 super().__init__()
 self._inode_path_map = { llfuse.ROOT_INODE: source }
 self._lookup_cnt = defaultdict(lambda : 0)
 self._fd_inode_map = dict()
 self._inode_fd_map = dict()
 self._fd_open_count = dict()

def _inode_to_path(self, inode):
 try:
 val = self._inode_path_map[inode]
 except KeyError:
 raise FUSEError(errno.ENOENT)

if isinstance(val, set):
 # In case of hardlinks, pick any path
 val = next(iter(val))
 return val

def _add_path(self, inode, path):
 log.debug(&#39;_add_path for %d, %s&#39;, inode, path)
 self._lookup_cnt[inode] += 1

# With hardlinks, one inode may map to multiple paths.
 if inode not in self._inode_path_map:
 self._inode_path_map[inode] = path
 return

val = self._inode_path_map[inode]
 if isinstance(val, set):
 val.add(path)
 elif val != path:
 self._inode_path_map[inode] = { path, val }

def forget(self, inode_list):
 for (inode, nlookup) in inode_list:
 if self._lookup_cnt[inode] &gt; nlookup:
 self._lookup_cnt[inode] -= nlookup
 continue
 log.debug(&#39;forgetting about inode %d&#39;, inode)
 assert inode not in self._inode_fd_map
 del self._lookup_cnt[inode]
 try:
 del self._inode_path_map[inode]
 except KeyError: # may have been deleted
 pass

def lookup(self, inode_p, name, ctx=None):
 name = fsdecode(name)
 log.debug(&#39;lookup for %s in %d&#39;, name, inode_p)
 path = os.path.join(self._inode_to_path(inode_p), name)
 attr = self._getattr(path=path)
 if name != &#39;.&#39; and name != &#39;..&#39;:
 self._add_path(attr.st_ino, path)
 return attr

def _getattr(self, path=None, fd=None):
 assert fd is None or path is None
 assert not(fd is None and path is None)
 try:
 if fd is None:
 stat = os.lstat(path)
 else:
 stat = os.fstat(fd)
 except OSError as exc:
 raise FUSEError(exc.errno)

entry = llfuse.EntryAttributes()
 for attr in (&#39;st_ino&#39;, &#39;st_mode&#39;, &#39;st_nlink&#39;, &#39;st_uid&#39;, &#39;st_gid&#39;,
 &#39;st_rdev&#39;, &#39;st_size&#39;, &#39;st_atime_ns&#39;, &#39;st_mtime_ns&#39;,
 &#39;st_ctime_ns&#39;):
 setattr(entry, attr, getattr(stat, attr))
 entry.generation = 0
 entry.entry_timeout = 5
 entry.attr_timeout = 5
 entry.st_blksize = 512
 entry.st_blocks = ((entry.st_size+entry.st_blksize-1) // entry.st_blksize)

return entry

def readlink(self, inode, ctx):
 path = self._inode_to_path(inode)
 try:
 target = os.readlink(path)
 except OSError as exc:
 raise FUSEError(exc.errno)
 return fsencode(target)

def readdir(self, inode, off):
 path = self._inode_to_path(inode)
 log.debug(&#39;reading %s&#39;, path)
 entries = []
 for name in os.listdir(path):
 attr = self._getattr(path=os.path.join(path, name))
 entries.append((attr.st_ino, name, attr))

log.debug(&#39;read %d entries, starting at %d&#39;, len(entries), off)

# This is not fully posix compatible. If there are hardlinks
 # (two names with the same inode), we don&#39;t have a unique
 # offset to start in between them. Note that we cannot simply
 # count entries, because then we would skip over entries
 # (or return them more than once) if the number of directory
 # entries changes between two calls to readdir().
 for (ino, name, attr) in sorted(entries):
 if ino &lt;= off:
 continue
 yield (fsencode(name), attr, ino)

def unlink(self, inode_p, name, ctx):
 name = fsdecode(name)
 parent = self._inode_to_path(inode_p)
 path = os.path.join(parent, name)
 try:
 inode = os.lstat(path).st_ino
 os.unlink(path)
 except OSError as exc:
 raise FUSEError(exc.errno)
 if inode in self._lookup_cnt:
 self._forget_path(inode, path)

def rmdir(self, inode_p, name, ctx):
 name = fsdecode(name)
 parent = self._inode_to_path(inode_p)
 path = os.path.join(parent, name)
 try:
 inode = os.lstat(path).st_ino
 os.rmdir(path)
 except OSError as exc:
 raise FUSEError(exc.errno)
 if inode in self._lookup_cnt:
 self._forget_path(inode, path)

def _forget_path(self, inode, path):
 log.debug(&#39;forget %s for %d&#39;, path, inode)
 val = self._inode_path_map[inode]
 if isinstance(val, set):
 val.remove(path)
 if len(val) == 1:
 self._inode_path_map[inode] = next(iter(val))
 else:
 del self._inode_path_map[inode]

def symlink(self, inode_p, name, target, ctx):
 name = fsdecode(name)
 target = fsdecode(target)
 parent = self._inode_to_path(inode_p)
 path = os.path.join(parent, name)
 try:
 os.symlink(target, path)
 os.chown(path, ctx.uid, ctx.gid, follow_symlinks=False)
 except OSError as exc:
 raise FUSEError(exc.errno)
 stat = os.lstat(path)
 self._add_path(stat.st_ino, path)
 return self.getattr(stat.st_ino)

def rename(self, inode_p_old, name_old, inode_p_new, name_new, ctx):
 name_old = fsdecode(name_old)
 name_new = fsdecode(name_new)
 parent_old = self._inode_to_path(inode_p_old)
 parent_new = self._inode_to_path(inode_p_new)
 path_old = os.path.join(parent_old, name_old)
 path_new = os.path.join(parent_new, name_new)
 try:
 os.rename(path_old, path_new)
 inode = os.lstat(path_new).st_ino
 except OSError as exc:
 raise FUSEError(exc.errno)
 if inode not in self._lookup_cnt:
 return

val = self._inode_path_map[inode]
 if isinstance(val, set):
 assert len(val) &gt; 1
 val.add(path_new)
 val.remove(path_old)
 else:
 assert val == path_old
 self._inode_path_map[inode] = path_new

def link(self, inode, new_inode_p, new_name, ctx):
 new_name = fsdecode(new_name)
 parent = self._inode_to_path(new_inode_p)
 path = os.path.join(parent, new_name)
 try:
 os.link(self._inode_to_path(inode), path, follow_symlinks=False)
 except OSError as exc:
 raise FUSEError(exc.errno)
 self._add_path(inode, path)
 return self.getattr(inode)

def setattr(self, inode, attr, fields, fh, ctx):
 # We use the f* functions if possible so that we can handle
 # a setattr() call for an inode without associated directory
 # handle.
 if fh is None:
 path_or_fh = self._inode_to_path(inode)
 truncate = os.truncate
 chmod = os.chmod
 chown = os.chown
 stat = os.lstat
 else:
 path_or_fh = fh
 truncate = os.ftruncate
 chmod = os.fchmod
 chown = os.fchown
 stat = os.fstat

try:
 if fields.update_size:
 truncate(path_or_fh, attr.st_size)

if fields.update_mode:
 # Under Linux, chmod always resolves symlinks so we should
 # actually never get a setattr() request for a symbolic
 # link.
 assert not stat_m.S_ISLNK(attr.st_mode)
 chmod(path_or_fh, stat_m.S_IMODE(attr.st_mode))

if fields.update_uid:
 chown(path_or_fh, attr.st_uid, -1, follow_symlinks=False)

if fields.update_gid:
 chown(path_or_fh, -1, attr.st_gid, follow_symlinks=False)

if fields.update_atime and fields.update_mtime:
 # utime accepts both paths and file descriptiors
 os.utime(path_or_fh, None, follow_symlinks=False,
 ns=(attr.st_atime_ns, attr.st_mtime_ns))
 elif fields.update_atime or fields.update_mtime:
 # We can only set both values, so we first need to retrieve the
 # one that we shouldn&#39;t be changing.
 oldstat = stat(path_or_fh)
 if not fields.update_atime:
 attr.st_atime_ns = oldstat.st_atime_ns
 else:
 attr.st_mtime_ns = oldstat.st_mtime_ns
 os.utime(path_or_fh, None, follow_symlinks=False,
 ns=(attr.st_atime_ns, attr.st_mtime_ns))

except OSError as exc:
 raise FUSEError(exc.errno)

return self.getattr(inode)

def mknod(self, inode_p, name, mode, rdev, ctx):
 path = os.path.join(self._inode_to_path(inode_p), fsdecode(name))
 try:
 os.mknod(path, mode=(mode &amp; ~ctx.umask), device=rdev)
 os.chown(path, ctx.uid, ctx.gid)
 except OSError as exc:
 raise FUSEError(exc.errno)
 attr = self._getattr(path=path)
 self._add_path(attr.st_ino, path)
 return attr

def mkdir(self, inode_p, name, mode, ctx):
 path = os.path.join(self._inode_to_path(inode_p), fsdecode(name))
 try:
 os.mkdir(path, mode=(mode &amp; ~ctx.umask))
 os.chown(path, ctx.uid, ctx.gid)
 except OSError as exc:
 raise FUSEError(exc.errno)
 attr = self._getattr(path=path)
 self._add_path(attr.st_ino, path)
 return attr

def statfs(self, ctx):
 root = self._inode_path_map[llfuse.ROOT_INODE]
 stat_ = llfuse.StatvfsData()
 try:
 statfs = os.statvfs(root)
 except OSError as exc:
 raise FUSEError(exc.errno)
 for attr in (&#39;f_bsize&#39;, &#39;f_frsize&#39;, &#39;f_blocks&#39;, &#39;f_bfree&#39;, &#39;f_bavail&#39;,
 &#39;f_files&#39;, &#39;f_ffree&#39;, &#39;f_favail&#39;):
 setattr(stat_, attr, getattr(statfs, attr))
 stat_.f_namemax = statfs.f_namemax - (len(root)+1)
 return stat_

def open(self, inode, flags, ctx):
 if inode in self._inode_fd_map:
 fd = self._inode_fd_map[inode]
 self._fd_open_count[fd] += 1
 return fd
 assert flags &amp; os.O_CREAT == 0
 try:
 fd = os.open(self._inode_to_path(inode), flags)
 except OSError as exc:
 raise FUSEError(exc.errno)
 self._inode_fd_map[inode] = fd
 self._fd_inode_map[fd] = inode
 self._fd_open_count[fd] = 1
 return fd

def create(self, inode_p, name, mode, flags, ctx):
 path = os.path.join(self._inode_to_path(inode_p), fsdecode(name))
 try:
 fd = os.open(path, flags | os.O_CREAT | os.O_TRUNC)
 except OSError as exc:
 raise FUSEError(exc.errno)
 attr = self._getattr(fd=fd)
 self._add_path(attr.st_ino, path)
 self._inode_fd_map[attr.st_ino] = fd
 self._fd_inode_map[fd] = attr.st_ino
 self._fd_open_count[fd] = 1
 return (fd, attr)

def read(self, fd, offset, length):
 os.lseek(fd, offset, os.SEEK_SET)
 return os.read(fd, length)

def write(self, fd, offset, buf):
 os.lseek(fd, offset, os.SEEK_SET)
 return os.write(fd, buf)

def release(self, fd):
 if self._fd_open_count[fd] &gt; 1:
 self._fd_open_count[fd] -= 1
 return

del self._fd_open_count[fd]
 inode = self._fd_inode_map[fd]
 del self._inode_fd_map[inode]
 del self._fd_inode_map[fd]
 try:
 os.close(fd)
 except OSError as exc:
 raise FUSEError(exc.errno)

def parse_args(args):
 &#39;&#39;&#39;Parse command line&#39;&#39;&#39;

parser = ArgumentParser()

parser.add_argument(&#39;source&#39;, type=str,
 help=&#39;Directory tree to mirror&#39;)
 parser.add_argument(&#39;mountpoint&#39;, type=str,
 help=&#39;Where to mount the file system&#39;)
 parser.add_argument(&#39;--single&#39;, action=&#39;store_true&#39;, default=False,
 help=&#39;Run single threaded&#39;)
 parser.add_argument(&#39;--debug&#39;, action=&#39;store_true&#39;, default=False,
 help=&#39;Enable debugging output&#39;)
 parser.add_argument(&#39;--debug-fuse&#39;, action=&#39;store_true&#39;, default=False,
 help=&#39;Enable FUSE debugging output&#39;)

return parser.parse_args(args)

def main():
 options = parse_args(sys.argv[1:])
 init_logging(options.debug)
 operations = Operations(options.source)

log.debug(&#39;Mounting...&#39;)
 fuse_options = set(llfuse.default_options)
 fuse_options.add(&#39;fsname=passthroughfs&#39;)
 if options.debug_fuse:
 fuse_options.add(&#39;debug&#39;)
 llfuse.init(operations, options.mountpoint, fuse_options)

try:
 log.debug(&#39;Entering main loop..&#39;)
 if options.single:
 llfuse.main(workers=1)
 else:
 llfuse.main()
 except:
 llfuse.close(unmount=False)
 raise

log.debug(&#39;Unmounting..&#39;)
 llfuse.close()

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