vfs: fix d_need_lookup/d_revalidate order in do_lookup

Doing revalidate on a dentry which has not yet been looked up makes no sense.

Move the d_need_lookup() check before d_revalidate().

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/namei.c b/fs/namei.c
index e615ff3..768f236 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -1139,6 +1139,8 @@
 			return -ECHILD;
 		nd->seq = seq;
 
+		if (unlikely(d_need_lookup(dentry)))
+			goto unlazy;
 		if (unlikely(dentry->d_flags & DCACHE_OP_REVALIDATE)) {
 			status = d_revalidate(dentry, nd);
 			if (unlikely(status <= 0)) {
@@ -1147,8 +1149,6 @@
 				goto unlazy;
 			}
 		}
-		if (unlikely(d_need_lookup(dentry)))
-			goto unlazy;
 		path->mnt = mnt;
 		path->dentry = dentry;
 		if (unlikely(!__follow_mount_rcu(nd, path, inode)))