untangling do_lookup() - take __lookup_hash()-calling case out of line.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/namei.c

@@ -1208,22 +1208,14 @@ static int do_lookup(struct nameidata *nd, struct qstr *name,
 		dentry = __d_lookup(parent, name);
 	}
 
-	if (dentry && unlikely(d_need_lookup(dentry))) {
+	if (unlikely(!dentry))
+		goto need_lookup;
+
+	if (unlikely(d_need_lookup(dentry))) {
 		dput(dentry);
-		dentry = NULL;
+		goto need_lookup;
 	}
-retry:
-	if (unlikely(!dentry)) {
-		struct inode *dir = parent->d_inode;
-		BUG_ON(nd->inode != dir);
 
-		mutex_lock(&dir->i_mutex);
-		dentry = __lookup_hash(name, parent, nd);
-		mutex_unlock(&dir->i_mutex);
-		if (IS_ERR(dentry))
-			return PTR_ERR(dentry);
-		goto done;
-	}
 	if (unlikely(dentry->d_flags & DCACHE_OP_REVALIDATE) && need_reval)
 		status = d_revalidate(dentry, nd);
 	if (unlikely(status <= 0)) {
@@ -1233,8 +1225,7 @@ static int do_lookup(struct nameidata *nd, struct qstr *name,
 		}
 		if (!d_invalidate(dentry)) {
 			dput(dentry);
-			dentry = NULL;
-			goto retry;
+			goto need_lookup;
 		}
 	}
 done:
@@ -1249,6 +1240,16 @@ static int do_lookup(struct nameidata *nd, struct qstr *name,
 		nd->flags |= LOOKUP_JUMPED;
 	*inode = path->dentry->d_inode;
 	return 0;
+
+need_lookup:
+	BUG_ON(nd->inode != parent->d_inode);
+
+	mutex_lock(&parent->d_inode->i_mutex);
+	dentry = __lookup_hash(name, parent, nd);
+	mutex_unlock(&parent->d_inode->i_mutex);
+	if (IS_ERR(dentry))
+		return PTR_ERR(dentry);
+	goto done;
 }
 
 static inline int may_lookup(struct nameidata *nd)