diff --git a/build/bazel/remote/execution/v2/remote_execution.proto b/build/bazel/remote/execution/v2/remote_execution.proto
index 9bb88a4a..40e97e76 100644
--- a/build/bazel/remote/execution/v2/remote_execution.proto
+++ b/build/bazel/remote/execution/v2/remote_execution.proto
@@ -779,6 +779,14 @@ message FileNode {
   // The node properties of the FileNode.
   reserved 5;
   NodeProperties node_properties = 6;
+
+  // Salt to force that files in the input root have distinct inode
+  // numbers, even if all properties match.
+  //
+  // Two files with in the input root SHOULD have the same inode number
+  // iff they have the same digest, is_executable flag, node_properties,
+  // and hardlink_salt.
+  bytes hardlink_salt = 7;
 }
 
 // A `DirectoryNode` represents a child of a