1 files changed, 5 insertions, 0 deletions

diff --git a/include/linux/exportfs.h b/include/linux/exportfs.h
index c7e6b6392ab8..5b9b5b317180 100644
--- a/include/linux/exportfs.h
+++ b/include/linux/exportfs.h
@@ -83,6 +83,11 @@ enum fid_type {
          * 64 bit parent inode number.
          */
         FILEID_NILFS_WITH_PARENT = 0x62,
+
+        /*
+         * Filesystems must not use 0xff file ID.
+         */
+        FILEID_INVALID = 0xff,
 };
 
 struct fid {