diff --git a/servers/src/main/java/tachyon/master/next/filesystem/FileSystemMaster.java b/servers/src/main/java/tachyon/master/next/filesystem/FileSystemMaster.java
index <HASH>..<HASH> 100644
--- a/servers/src/main/java/tachyon/master/next/filesystem/FileSystemMaster.java
+++ b/servers/src/main/java/tachyon/master/next/filesystem/FileSystemMaster.java
@@ -264,6 +264,7 @@ public class FileSystemMaster implements Master {
         throw new FileDoesNotExistException("File " + fileId + " is a directory.");
       }
 
+      // TODO: allow "committing" existing blocks, for lineage.
       // Try to commit this block.
       ((InodeFile) inode).commitBlock(blockId, length);
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