diff --git a/fs/jfs/jfs_dmap.c b/fs/jfs/jfs_dmap.c
index 63ad6b1d575a..b20fffc8b4c1 100644
--- a/fs/jfs/jfs_dmap.c
+++ b/fs/jfs/jfs_dmap.c
@@ -282,6 +282,7 @@ int dbUnmount(struct inode *ipbmap, int mounterror)
 
 	/* free the memory for the in-memory bmap. */
 	kfree(bmp);
+	JFS_SBI(ipbmap->i_sb)->bmap = NULL;
 
 	return (0);
 }