add unionfs

diff --git a/docs/developer/gsocprojectspage/index.mdwn b/docs/developer/gsocprojectspage/index.mdwn
index 3355cf9..9b1a2c8 100644 (file)
--- a/docs/developer/gsocprojectspage/index.mdwn
+++ b/docs/developer/gsocprojectspage/index.mdwn
@@ -286,5 +286,19 @@ Meta information:
 * Difficulty: Medium
 * Contact point: kernel@crater.dragonflybsd.org , Alex Hornung <alexh@dragonflybsd.org>
 
+---
+
+##### Implement a new unionfs
+* unionfs is a particularly useful pseudo-fs which allows to have an upper and a lower filesystem on a single mountpoint. The upper mountpoint is mostly transparent, so that the lower mountpoint is accessible.
+
+* A typical use case is mounting a tmpfs filesystem as the upper and a read-only FS as the lower mp. This way files can be edited transparently even on a RO filesystem without actually modifying it.
+
+* The current unionfs is completely broken as it relies on the whiteout VFS technique which is not supported by HAMMER.
+
+Meta information:
+
+* Prerequisites: C, OS internals, ideally some knowledge of the FreeBSD/DragonFly VFS
+* Difficulty: Medium
+* Contact point: kernel@crater.dragonflybsd.org
 
  (please add)