ovl: add ovl_dentry_is_whiteout()

And use it instead of ovl_dentry_is_opaque() where appropriate.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>

fs/overlayfs/dir.c

@@ -504,7 +504,7 @@ static int ovl_create_or_link(struct dentry *dentry, struct inode *inode,
 		put_cred(override_creds(override_cred));
 		put_cred(override_cred);
 
-		if (!ovl_dentry_is_opaque(dentry))
+		if (!ovl_dentry_is_whiteout(dentry))
 			err = ovl_create_upper(dentry, inode, stat, link,
 						hardlink);
 		else
@@ -842,14 +842,14 @@ static int ovl_rename(struct inode *olddir, struct dentry *old,
 
 	if (overwrite) {
 		if (old_opaque) {
-			if (new->d_inode || !new_opaque) {
+			if (!ovl_dentry_is_whiteout(new)) {
 				/* Whiteout source */
 				flags |= RENAME_WHITEOUT;
 			} else {
 				/* Switch whiteouts */
 				flags |= RENAME_EXCHANGE;
 			}
-		} else if (is_dir && !new->d_inode && new_opaque) {
+		} else if (is_dir && ovl_dentry_is_whiteout(new)) {
 			flags |= RENAME_EXCHANGE;
 			cleanup_whiteout = true;
 		}

fs/overlayfs/overlayfs.h

@@ -161,6 +161,7 @@ struct dentry *ovl_workdir(struct dentry *dentry);
 int ovl_want_write(struct dentry *dentry);
 void ovl_drop_write(struct dentry *dentry);
 bool ovl_dentry_is_opaque(struct dentry *dentry);
+bool ovl_dentry_is_whiteout(struct dentry *dentry);
 void ovl_dentry_set_opaque(struct dentry *dentry, bool opaque);
 bool ovl_is_whiteout(struct dentry *dentry);
 const struct cred *ovl_override_creds(struct super_block *sb);

fs/overlayfs/super.c

@@ -209,6 +209,11 @@ bool ovl_dentry_is_opaque(struct dentry *dentry)
 	return oe->opaque;
 }
 
+bool ovl_dentry_is_whiteout(struct dentry *dentry)
+{
+	return !dentry->d_inode && ovl_dentry_is_opaque(dentry);
+}
+
 void ovl_dentry_set_opaque(struct dentry *dentry, bool opaque)
 {
 	struct ovl_entry *oe = dentry->d_fsdata;