diff --git a/Documentation/filesystems/nfs/Exporting b/Documentation/filesystems/nfs/Exporting
index 87019d2b5981..09994c247289 100644
--- a/Documentation/filesystems/nfs/Exporting
+++ b/Documentation/filesystems/nfs/Exporting
@@ -92,7 +92,14 @@ For a filesystem to be exportable it must:
    1/ provide the filehandle fragment routines described below.
    2/ make sure that d_splice_alias is used rather than d_add
       when ->lookup finds an inode for a given parent and name.
-      Typically the ->lookup routine will end with a:
+
+      If inode is NULL, d_splice_alias(inode, dentry) is eqivalent to
+
+		d_add(dentry, inode), NULL
+
+      Similarly, d_splice_alias(ERR_PTR(err), dentry) = ERR_PTR(err)
+
+      Typically the ->lookup routine will simply end with a:
 
 		return d_splice_alias(inode, dentry);
 	}