Change put_file loop condition to f1.tell (#870)

Author: brandon-leapyear

fsspec/spec.py

@@ -809,7 +809,7 @@ def put_file(self, lpath, rpath, callback=_DEFAULT_CALLBACK, **kwargs):
 
             self.mkdirs(self._parent(os.fspath(rpath)), exist_ok=True)
             with self.open(rpath, "wb", **kwargs) as f2:
-                while f2.tell() < size:
+                while f1.tell() < size:
                     data = f1.read(self.blocksize)
                     segment_len = f2.write(data)
                     callback.relative_update(segment_len)