diff --git a/swh/model/git.py b/swh/model/git.py
--- a/swh/model/git.py
+++ b/swh/model/git.py
@@ -1,10 +1,11 @@
-# Copyright (C) 2015  The Software Heritage developers
+# Copyright (C) 2015-2017  The Software Heritage developers
 # See the AUTHORS file at the top-level directory of this distribution
 # License: GNU General Public License version 3, or any later version
 # See top-level LICENSE file for more information
 
 
 import os
+import stat
 
 from enum import Enum
 
@@ -160,17 +161,24 @@
 
     Args:
         filepath: absolute pathname of the file.
+                  Special file (fifo, character or
+                  block device) are considered empty and None is returned.
 
     Returns:
         Dictionary of values:
             - name: basename of the file
+            - length: data length
             - perms: git permission for file
             - type: git type for file
             - path: absolute filepath on filesystem
 
     """
-    blob_metadata = hashutil.hash_path(filepath)
+    mode = os.lstat(filepath).st_mode
+    if not stat.S_ISREG(mode):  # block or character device, fifo, etc...
+        return None
+
     perms = GitPerm.EXEC if os.access(filepath, os.X_OK) else GitPerm.BLOB
+    blob_metadata = hashutil.hash_path(filepath)
     blob_metadata.update({
         'name': os.path.basename(filepath),
         'perms': perms,
@@ -394,7 +402,8 @@
 
         for filepath in (file for file in filenames if file not in all_links):
             m_hashes = compute_blob_metadata(filepath)
-            hashes.append(m_hashes)
+            if m_hashes:
+                hashes.append(m_hashes)
 
         ls_hashes[dirpath] = hashes
 
@@ -494,10 +503,11 @@
 
         for filepath in (file for file in filenames if file not in all_links):
             m_hashes = compute_blob_metadata(filepath)
-            d = _get_dict_from_filepath(ls_hashes, filepath)
-            d['checksums'] = m_hashes
-            ls_hashes[filepath] = d
-            children.add(filepath)
+            if m_hashes:
+                d = _get_dict_from_filepath(ls_hashes, filepath)
+                d['checksums'] = m_hashes
+                ls_hashes[filepath] = d
+                children.add(filepath)
 
         for fulldirname in (dir for dir in dirnames if dir not in all_links):
             d_hashes = _get_dict_from_dirpath(ls_hashes, fulldirname)
diff --git a/swh/model/tests/test_git.py b/swh/model/tests/test_git.py
--- a/swh/model/tests/test_git.py
+++ b/swh/model/tests/test_git.py
@@ -1,4 +1,4 @@
-# Copyright (C) 2015  The Software Heritage developers
+# Copyright (C) 2015-2017  The Software Heritage developers
 # See the AUTHORS file at the top-level directory of this distribution
 # License: GNU General Public License version 3, or any later version
 # See top-level LICENSE file for more information
@@ -138,6 +138,27 @@
         self.assertEqual(checksum, self.checksums['tag_sha1_git'])
 
 
+@attr('fs')
+class ComputeBlobMetadata(unittest.TestCase):
+    @istest
+    def compute_blob_metadata__special_file_returns_nothing(self):
+        # prepare
+        tmp_root_path = tempfile.mkdtemp().encode('utf-8')
+        path = os.path.join(tmp_root_path, b'fifo-file')
+
+        # given
+        os.mkfifo(path)
+
+        # when
+        actual_metadata = git.compute_blob_metadata(path)
+
+        # then
+        self.assertIsNone(actual_metadata)
+
+        # cleanup
+        shutil.rmtree(tmp_root_path)
+
+
 @attr('fs')
 class GitHashWalkArborescenceTree:
     """Root class to ease walk and git hash testing without side-effecty