Btrfs: try to drop dead cow pages from ram

Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/TODO b/fs/btrfs/TODO
index 5ff2cef..6a8c8cd 100644
--- a/fs/btrfs/TODO
+++ b/fs/btrfs/TODO
@@ -6,8 +6,7 @@
 * Check compat and incompat flags on the inode
 * Get rid of struct ctree_path, limiting tree levels held at one time
 * Add generation number to key pointer in nodes
-* Add parent pointer back to extent map.
-* Implement real list of pending transactions
+* Add generation number to inode
 * Release
 * Do real tree locking
 * Add extent mirroring (backup copies of blocks)