From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-13.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 78EE0C4361B for ; Wed, 16 Dec 2020 02:37:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4A1D3230FA for ; Wed, 16 Dec 2020 02:37:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726307AbgLPCht (ORCPT ); Tue, 15 Dec 2020 21:37:49 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43530 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725819AbgLPCht (ORCPT ); Tue, 15 Dec 2020 21:37:49 -0500 Received: from ZenIV.linux.org.uk (zeniv.linux.org.uk [IPv6:2002:c35c:fd02::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7F7E8C0613D6 for ; Tue, 15 Dec 2020 18:37:08 -0800 (PST) Received: from viro by ZenIV.linux.org.uk with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1kpMgd-001Z2q-5Z; Wed, 16 Dec 2020 02:37:07 +0000 Date: Wed, 16 Dec 2020 02:37:07 +0000 From: Al Viro To: Jens Axboe Cc: linux-fsdevel@vger.kernel.org, torvalds@linux-foundation.org Subject: Re: [PATCH 3/4] fs: expose LOOKUP_NONBLOCK through openat2() RESOLVE_NONBLOCK Message-ID: <20201216023707.GI3579531@ZenIV.linux.org.uk> References: <20201214191323.173773-1-axboe@kernel.dk> <20201214191323.173773-4-axboe@kernel.dk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201214191323.173773-4-axboe@kernel.dk> Sender: Al Viro Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Mon, Dec 14, 2020 at 12:13:23PM -0700, Jens Axboe wrote: > Now that we support non-blocking path resolution internally, expose it > via openat2() in the struct open_how ->resolve flags. This allows > applications using openat2() to limit path resolution to the extent that > it is already cached. > > If the lookup cannot be satisfied in a non-blocking manner, openat2(2) > will return -1/-EAGAIN. > > Cc: Al Viro > Signed-off-by: Jens Axboe > --- > fs/open.c | 6 ++++++ > include/linux/fcntl.h | 2 +- > include/uapi/linux/openat2.h | 4 ++++ > 3 files changed, 11 insertions(+), 1 deletion(-) > > diff --git a/fs/open.c b/fs/open.c > index 9af548fb841b..a83434cfe01c 100644 > --- a/fs/open.c > +++ b/fs/open.c > @@ -1087,6 +1087,12 @@ inline int build_open_flags(const struct open_how *how, struct open_flags *op) > lookup_flags |= LOOKUP_BENEATH; > if (how->resolve & RESOLVE_IN_ROOT) > lookup_flags |= LOOKUP_IN_ROOT; > + if (how->resolve & RESOLVE_NONBLOCK) { > + /* Don't bother even trying for create/truncate open */ > + if (flags & (O_TRUNC | O_CREAT)) > + return -EAGAIN; Why not O_TMPFILE here as well?