--- src/sys/kern/vfs_syscalls.c	2005/08/15 07:26:47	1.69
+++ src/sys/kern/vfs_syscalls.c	2005/08/25 18:34:14	1.70
@@ -1891,6 +1891,17 @@ again:
 			goto again;
 		}
 	}
+
+	/*
+	 * The fsmid can be used to detect that something has changed
+	 * at or below the specified file/dir in the filesystem.  At
+	 * a minimum the fsmid is synthesized by the kernel via the 
+	 * namecache and requires an open descriptor for deterministic
+	 * operation.  Filesystems supporting fsmid may store it in the
+	 * inode, but this is not a requirement.
+	 */
+	st->st_fsmid = nd->nl_ncp->nc_fsmid;
+
 	vput(vp);
 	return (error);
 }