diff --git a/swiftonfile/swift/common/utils.py b/swiftonfile/swift/common/utils.py
index a1c9f24..aa8d0ce 100644
--- a/swiftonfile/swift/common/utils.py
+++ b/swiftonfile/swift/common/utils.py
@@ -38,6 +38,7 @@ X_TIMESTAMP = 'X-Timestamp'
 X_TYPE = 'X-Type'
 X_ETAG = 'ETag'
 X_OBJECT_TYPE = 'X-Object-Type'
+X_MTIME = 'X-Object-PUT-Mtime'
 DIR_TYPE = 'application/directory'
 METADATA_KEY = 'user.swift.metadata'
 MAX_XATTR_SIZE = 65536
@@ -217,7 +218,7 @@ def clean_metadata(path_or_fd):
         key += 1
 
 
-def validate_object(metadata, stat=None):
+def validate_object(metadata, statinfo=None):
     if not metadata:
         return False
 
@@ -229,11 +230,17 @@ def validate_object(metadata, stat=None):
        X_OBJECT_TYPE not in metadata.keys():
         return False
 
-    if stat and (int(metadata[X_CONTENT_LENGTH]) != stat.st_size):
-        # File length has changed.
-        # TODO: Handle case where file content has changed but the length
-        # remains the same.
-        return False
+    if statinfo and stat.S_ISREG(statinfo.st_mode):
+
+        # File length has changed
+        if int(metadata[X_CONTENT_LENGTH]) != statinfo.st_size:
+            return False
+
+        # File might have changed with length being the same.
+        if X_MTIME in metadata and \
+                normalize_timestamp(metadata[X_MTIME]) != \
+                normalize_timestamp(statinfo.st_mtime):
+            return False
 
     if metadata[X_TYPE] == OBJECT:
         return True
@@ -308,6 +315,7 @@ def get_object_metadata(obj_path_or_fd):
             X_CONTENT_TYPE: DIR_TYPE if is_dir else FILE_TYPE,
             X_OBJECT_TYPE: DIR_NON_OBJECT if is_dir else FILE,
             X_CONTENT_LENGTH: 0 if is_dir else stats.st_size,
+            X_MTIME: 0 if is_dir else normalize_timestamp(stats.st_mtime),
             X_ETAG: md5().hexdigest() if is_dir else _get_etag(obj_path_or_fd)}
     return metadata
 
diff --git a/swiftonfile/swift/obj/diskfile.py b/swiftonfile/swift/obj/diskfile.py
index 14f48ed..9f9d15e 100644
--- a/swiftonfile/swift/obj/diskfile.py
+++ b/swiftonfile/swift/obj/diskfile.py
@@ -44,7 +44,7 @@ from swiftonfile.swift.common.utils import read_metadata, write_metadata, \
 from swiftonfile.swift.common.utils import X_CONTENT_TYPE, \
     X_TIMESTAMP, X_TYPE, X_OBJECT_TYPE, FILE, OBJECT, DIR_TYPE, \
     FILE_TYPE, DEFAULT_UID, DEFAULT_GID, DIR_NON_OBJECT, DIR_OBJECT, \
-    X_ETAG, X_CONTENT_LENGTH
+    X_ETAG, X_CONTENT_LENGTH, X_MTIME
 from swift.obj.diskfile import DiskFileManager as SwiftDiskFileManager
 from swift.obj.diskfile import get_async_dir
 
@@ -169,7 +169,7 @@ def make_directory(full_path, uid, gid, metadata=None):
         return True, metadata
 
 
-def _adjust_metadata(metadata):
+def _adjust_metadata(fd, metadata):
     # Fix up the metadata to ensure it has a proper value for the
     # Content-Type metadata, as well as an X_TYPE and X_OBJECT_TYPE
     # metadata values.
@@ -189,6 +189,12 @@ def _adjust_metadata(metadata):
         else:
             metadata[X_OBJECT_TYPE] = FILE
 
+    # stat.st_mtime does not change after last write(). We set this to later
+    # detect if the object was changed from filesystem interface (non Swift)
+    statinfo = do_fstat(fd)
+    if stat.S_ISREG(statinfo.st_mode):
+        metadata[X_MTIME] = normalize_timestamp(statinfo.st_mtime)
+
     metadata[X_TYPE] = OBJECT
     return metadata
 
@@ -385,7 +391,7 @@ class DiskFileWriter(object):
                                      name
         """
         assert self._tmppath is not None
-        metadata = _adjust_metadata(metadata)
+        metadata = _adjust_metadata(self._fd, metadata)
         df = self._disk_file
 
         if dir_is_object(metadata):
diff --git a/test/functional/swift_on_file_tests.py b/test/functional/swift_on_file_tests.py
index acead57..26c045c 100644
--- a/test/functional/swift_on_file_tests.py
+++ b/test/functional/swift_on_file_tests.py
@@ -226,3 +226,17 @@ class TestSwiftOnFile(Base):
         self.assert_status(200)
         self.assertEqual(new_data_hash, metadata['etag'])
         self.assertEqual(len(new_data), int(metadata['content_length']))
+
+        # Modify the file but let the length remain same
+        new_data = "I am Antman"
+        new_data_hash = hashlib.md5(new_data).hexdigest()
+        with open(file_path, 'w') as f:
+            f.write(new_data)
+        # Make sure GET works
+        self.assertEqual(new_data, object_item.read())
+        self.assert_status(200)
+        # Check Etag and content-length is right
+        metadata = object_item.info()
+        self.assert_status(200)
+        self.assertEqual(new_data_hash, metadata['etag'])
+        self.assertEqual(len(new_data), int(metadata['content_length']))
diff --git a/test/unit/common/test_utils.py b/test/unit/common/test_utils.py
index 422134e..44d905b 100644
--- a/test/unit/common/test_utils.py
+++ b/test/unit/common/test_utils.py
@@ -533,9 +533,9 @@ class TestUtils(unittest.TestCase):
               utils.X_CONTENT_LENGTH: '12345',
               utils.X_TYPE: utils.OBJECT,
               utils.X_OBJECT_TYPE: 'na'}
-        fake_stat = Mock(st_size=12346)
+        fake_stat = Mock(st_size=12346, st_mode=33188)
         self.assertFalse(utils.validate_object(md, fake_stat))
-        fake_stat = Mock(st_size=12345)
+        fake_stat = Mock(st_size=12345, st_mode=33188)
         self.assertTrue(utils.validate_object(md, fake_stat))
 
     def test_write_pickle(self):
diff --git a/test/unit/obj/test_diskfile.py b/test/unit/obj/test_diskfile.py
index f1272f8..25d1de3 100644
--- a/test/unit/obj/test_diskfile.py
+++ b/test/unit/obj/test_diskfile.py
@@ -188,6 +188,7 @@ class TestDiskFile(unittest.TestCase):
             'Content-Length': 4,
             'ETag': etag,
             'X-Timestamp': ts,
+            'X-Object-PUT-Mtime': normalize_timestamp(stats.st_mtime),
             'Content-Type': 'application/octet-stream'}
         gdf = self._get_diskfile("vol0", "p57", "ufo47", "bar", "z")
         assert gdf._obj == "z"