Ensure StorageFull only raised on space starvation

Additional fix for lp 919255

Limit StorageFull to cases of genuine disk space starvation (ENOSPC or
EFBIG), in order to avoid confusion with 413 "Request entity too large"
status being returned from POST /images for issues unrelated to space.

Change-Id: Ib5e68e5d988d0f541803ffb3f37ddf88ac24e9dc

glance/store/filesystem.py

@@ -19,6 +19,7 @@
 A simple filesystem-backed store
 """
 
+import errno
 import hashlib
 import logging
 import os
@@ -204,8 +205,12 @@ class Store(glance.store.base.Store):
                     bytes_written += len(buf)
                     checksum.update(buf)
                     f.write(buf)
-        except IOError:
-            raise exception.StorageFull()
+        except IOError as e:
+            if e.errno in [errno.EFBIG, errno.ENOSPC]:
+                raise exception.StorageFull()
+            else:
+                raise
+
         checksum_hex = checksum.hexdigest()
 
         logger.debug(_("Wrote %(bytes_written)d bytes to %(filepath)s with "

glance/tests/unit/test_filesystem_store.py

@@ -17,6 +17,7 @@
 
 """Tests the filesystem backend store"""
 
+import errno
 import StringIO
 import hashlib
 import unittest
@@ -134,11 +135,7 @@ class TestStore(base.IsolatedUnitTest):
                           self.store.add,
                           image_id, image_file, 0)
 
-    def test_add_storage_full(self):
-        """
-        Tests that adding an image without enough space on disk
-        raises an appropriate exception
-        """
+    def _do_test_add_failure(self, errno, exception):
         ChunkedFile.CHUNKSIZE = 1024
         image_id = utils.generate_uuid()
         file_size = 1024 * 5  # 5K
@@ -147,13 +144,36 @@ class TestStore(base.IsolatedUnitTest):
         image_file = StringIO.StringIO(file_contents)
 
         def fake_IO_Error(size):
-            raise IOError
+            e = IOError()
+            e.errno = errno
+            raise e
 
         self.stubs.Set(image_file, 'read', fake_IO_Error)
-        self.assertRaises(exception.StorageFull,
+        self.assertRaises(exception,
                           self.store.add,
                           image_id, image_file, 0)
 
+    def test_add_storage_full(self):
+        """
+        Tests that adding an image without enough space on disk
+        raises an appropriate exception
+        """
+        self._do_test_add_failure(errno.ENOSPC, exception.StorageFull)
+
+    def test_add_file_too_big(self):
+        """
+        Tests that adding an excessively large image file
+        raises an appropriate exception
+        """
+        self._do_test_add_failure(errno.EFBIG, exception.StorageFull)
+
+    def test_add_other_failure(self):
+        """
+        Tests that a non-space-related IOError does not raise a
+        StorageFull exception.
+        """
+        self._do_test_add_failure(errno.ENOTDIR, IOError)
+
     def test_delete(self):
         """
         Test we can delete an existing image in the filesystem store