Use the right predicate in ->atomic_open() instances

->atomic_open() can be given an in-lookup dentry *or* a negative one
found in dcache.  Use d_in_lookup() to tell one from another, rather
than d_unhashed().

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/gfs2/inode.c b/fs/gfs2/inode.c
index 21dc784..9bad79f 100644
--- a/fs/gfs2/inode.c
+++ b/fs/gfs2/inode.c
@@ -1189,7 +1189,7 @@
 	struct dentry *d;
 	bool excl = !!(flags & O_EXCL);
 
-	if (!d_unhashed(dentry))
+	if (!d_in_lookup(dentry))
 		goto skip_lookup;
 
 	d = __gfs2_lookup(dir, dentry, file, opened);