Changeset c10099f in trunk

Timestamp:

2011-09-13T00:28:43Z (14 years ago)

Author:

david-sarah <david-sarah@…>

Branches:

master

Children:

2025e42

Parents:

4c33d85

Message:

interfaces: document that the 'fills-holes-with-zero-bytes' key should be used to detect whether a storage server has that behavior. refs #1528

File:

• src/allmydata/interfaces.py (modified) (2 diffs)

src/allmydata/interfaces.py ¶

@@ -215 +215 @@
         vector will be filled with zero bytes. In earlier versions the
         contents of this space was unspecified (and might end up containing
-        secrets).
+        secrets). Storage servers with the new zero-filling behavior will
+        advertise a true value for the 'fills-holes-with-zero-bytes' key
+        (under 'http://allmydata.org/tahoe/protocols/storage/v1') in their
+        version information.
 
         Each write vector is accompanied by a 'new_length' argument, which
@@ -229 +232 @@
         in that case.
 
-        If a storage client can rely on a server being of version v1.8.3 or
-        later, it can extend the file efficiently by writing a single zero
-        byte just before the new end-of-file. Otherwise it must explicitly
-        write zeroes to all bytes between the old and new end-of-file. In any
-        case it should avoid sending new_length larger than the size of the
-        data after applying all write vectors.
+        If a storage client knows that the server supports zero-filling, for
+        example from the 'fills-holes-with-zero-bytes' key in its version
+        information, it can extend the file efficiently by writing a single
+        zero byte just before the new end-of-file. Otherwise it must
+        explicitly write zeroes to all bytes between the old and new
+        end-of-file. In any case it should avoid sending new_length larger
+        than the size of the data after applying all write vectors.
 
         The read vector is used to extract data from all known shares,