diff --git a/fs/afs/flock.c b/fs/afs/flock.c
index af6952e..210acaf 100644
--- a/fs/afs/flock.c
+++ b/fs/afs/flock.c
@@ -524,8 +524,7 @@
 	       (long long) fl->fl_start, (long long) fl->fl_end);
 
 	/* AFS doesn't support mandatory locks */
-	if ((vnode->vfs_inode.i_mode & (S_ISGID | S_IXGRP)) == S_ISGID &&
-	    fl->fl_type != F_UNLCK)
+	if (__mandatory_lock(&vnode->vfs_inode) && fl->fl_type != F_UNLCK)
 		return -ENOLCK;
 
 	if (IS_GETLK(cmd))