ceph: return ceph_mdsc_do_request() errors from __get_parent()

Return the error returned by ceph_mdsc_do_request(). Otherwise,
r_target_inode ends up being NULL this ends up returning ENOENT
regardless of the error.
Signed-off-by: Qiujun Huang <hqjagain@gmail.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

fs/ceph/export.c

@@ -315,6 +315,11 @@ static struct dentry *__get_parent(struct super_block *sb,
 
 	req->r_num_caps = 1;
 	err = ceph_mdsc_do_request(mdsc, NULL, req);
+	if (err) {
+		ceph_mdsc_put_request(req);
+		return ERR_PTR(err);
+	}
+
 	inode = req->r_target_inode;
 	if (inode)
 		ihold(inode);