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=-6.9 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 B9087C433DB for ; Sat, 26 Dec 2020 18:26:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 711AE20855 for ; Sat, 26 Dec 2020 18:26:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726070AbgLZSYr (ORCPT ); Sat, 26 Dec 2020 13:24:47 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52960 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725989AbgLZSYr (ORCPT ); Sat, 26 Dec 2020 13:24:47 -0500 Received: from mail-pg1-x531.google.com (mail-pg1-x531.google.com [IPv6:2607:f8b0:4864:20::531]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 312D5C061757 for ; Sat, 26 Dec 2020 10:24:07 -0800 (PST) Received: by mail-pg1-x531.google.com with SMTP id e2so4892317pgi.5 for ; Sat, 26 Dec 2020 10:24:07 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20150623.gappssmtp.com; s=20150623; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=jSrK72G+LTRB59CVRGVZLVEHqQGskT1SJE3WCaELUco=; b=OXJWmMsj95kAmFcKp7NT4K7wAVvL+pAN1HgGTEYLIy2iSK82XZ6K/GSTZbQ8ZntpgT WIi9dK05eUXwkJLN67V+PbEtWUOFGYGdWgxJ1iL83cyPRwHq9Rh9k2P5J0mEyztQhibo M+Svr6V82pCw+LR0rw1hea5i4V4qzej9vkZFp5IVHNVZnquaJwkOrCiiUZinDLo6uokq BEoQdFr4WrHsehGtXBLA4FlncYqGLqtXju8gDkYaH2pUigL8JW/tIq9JnbpiAI0aw9Fu l0baCJUlckLTfihejxSC9gKEurgLiE6AkMQGFIi64znPQ/sO0cC7LROGuvENWHgxNEe/ BWLA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=jSrK72G+LTRB59CVRGVZLVEHqQGskT1SJE3WCaELUco=; b=shvQd+81ND5Wf3FTqgqOy/Vk3uEWFCoJzsWjvUpJ8/LI8RswIG9I0m96L4Ro9K52pL tDxldPwemc/rIEegc+7DFPoGRSUQV+hWZebN1r6racnrUo/oJv0GmqXhY0f+LydFHIPG cz1JS5inh9TQNQ9IYXzWrQh5EJ7N88F7XZuGL2hJb55XVT/YcvQ0K31YmlWz92o5gMYe +eF8hS3HU7TVnQBUVmctC104sBRTXTYz/QgwA4g+1xjbICXBJEZX7oDpYxg6gJOY5xh8 kxqoR5IXe9bbLP+v7obbm1cIAa3KzUNloAplnq6cFFpMoZUcPKn63jdpzjL1xsTOPZVR 5S9g== X-Gm-Message-State: AOAM5335em6Pk9HS+LSD9g+iV/lAX7YF4c71W6wx//m9ZyUO+PbYZ33j eXJqh3WBSq+3XowbB4WeB1JymeMzeu2B6A== X-Google-Smtp-Source: ABdhPJxKx6+5oviqTK+nRSQdnRnQDra+NldCNilUAtR/NzuL22dTQURfsMVI1wHhcr8j8GnKIOEoAA== X-Received: by 2002:a63:4563:: with SMTP id u35mr36252074pgk.162.1609007046689; Sat, 26 Dec 2020 10:24:06 -0800 (PST) Received: from [192.168.1.134] ([66.219.217.173]) by smtp.gmail.com with ESMTPSA id j3sm8486099pjs.50.2020.12.26.10.24.05 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sat, 26 Dec 2020 10:24:06 -0800 (PST) Subject: Re: [PATCH 1/4] fs: make unlazy_walk() error handling consistent To: Matthew Wilcox Cc: Al Viro , linux-fsdevel@vger.kernel.org, torvalds@linux-foundation.org References: <20201217161911.743222-1-axboe@kernel.dk> <20201217161911.743222-2-axboe@kernel.dk> <66d1d322-42d4-5a46-05fb-caab31d0d834@kernel.dk> <20201226045043.GA3579531@ZenIV.linux.org.uk> <9ce193e7-8609-7d96-4719-f1b316c927e6@kernel.dk> <20201226175801.GV874@casper.infradead.org> From: Jens Axboe Message-ID: <7f1cbbd7-a6ee-e1d3-e24e-02cb107ac86d@kernel.dk> Date: Sat, 26 Dec 2020 11:24:07 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20201226175801.GV874@casper.infradead.org> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On 12/26/20 10:58 AM, Matthew Wilcox wrote: > On Sat, Dec 26, 2020 at 10:33:25AM -0700, Jens Axboe wrote: >> +.TP >> +.B RESOLVE_CACHED >> +Make the open operation fail unless all path components are already present >> +in the kernels lookup cache. >> +If any kind of revalidation or IO is needed to satisfy the lookup, > > Usually spelled I/O in manpages. Changed, thanks! >> +.BR openat2 () >> +fails with the error >> +.B EAGAIN. >> +This is useful in providing a fast path open that can be performed without >> +resorting to thread offload, or other mechanism that an application might >> +use to offload slower operations. > > That almost reads backwards ... how about this? > > This provides a fast path open that can be used when an application does > not wish to block. It allows the application to hand off the lookup to > a separate thread which can block. I deliberately did not want to include anything about blocking, would prefer to just keep it about having the necessary data/state cached. -- Jens Axboe