Common Gotchas

This chapter lists some common gotchas that should be avoided.

Removing inodes in unlink handler

If your file system is mounted at mnt, the following code should complete without errors:

with open('mnt/file_one', 'w+') as fh1:
    fh1.write('foo')
    fh1.flush()
    with open('mnt/file_one', 'a') as fh2:
        os.unlink('mnt/file_one')
        assert 'file_one' not in os.listdir('mnt')
        fh2.write('bar')
    os.close(os.dup(fh1.fileno()))
    fh1.seek(0)
    assert fh1.read() == 'foobar'

If you’re getting an error, then you probably did a mistake when implementing the unlink handler and are removing the file contents when you should be deferring removal to the forget handler.