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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 55F58C433F5 for ; Mon, 22 Nov 2021 15:51:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238228AbhKVPyf (ORCPT ); Mon, 22 Nov 2021 10:54:35 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36466 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231714AbhKVPyf (ORCPT ); Mon, 22 Nov 2021 10:54:35 -0500 Received: from mail-pj1-x102d.google.com (mail-pj1-x102d.google.com [IPv6:2607:f8b0:4864:20::102d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8F999C061574 for ; Mon, 22 Nov 2021 07:51:28 -0800 (PST) Received: by mail-pj1-x102d.google.com with SMTP id j6-20020a17090a588600b001a78a5ce46aso17248538pji.0 for ; Mon, 22 Nov 2021 07:51:28 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:content-transfer-encoding:in-reply-to; bh=6+RrtX/RqIJP9MdrzcI2o2KCOQtGt5iHYtstZKO1Xjc=; b=WbO5Ojx4GL89XY0Y7ckwiUkjlDJiPLUuTP73bAcEz06GTAnL7EtGXQTFtrBFrXmHJy jLYn1pJlA21uyajZK1MI+XAGdxXHc+rE1HaOOrJ0Kv5CxBJ/kq820sRJKdHhRdhShkKj gyP2B4PHKlZHRu+nDcMwrytllDsp0haYDyaZibzlYqDgj/5qsos9/C3okRAFfHs+0ML+ d9aetsBZBGsAsBRPwCYEP9gYqeGIyeXjsllecMvIJZhwUnjD59+EWx8B9HVB4xU0URKB rm+fVU5wl3w9Xw0DKElgX51be6oT0WDzJ7RZZqEb2AORbgb/yB89N2CJTDPESjNMT7WM MvOg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:content-transfer-encoding :in-reply-to; bh=6+RrtX/RqIJP9MdrzcI2o2KCOQtGt5iHYtstZKO1Xjc=; b=PjxyqAQ9x6j+mIWHx1hwlFWpXSkhhfNO/bYU7rYIxHoWHCucjWA9rg8rB3Hbmmc/3Q NGkpu+l2yxIJrT6ZnD8FgGKzlGbhsMlJW3vegtMak8FswwDJPPujt1srxzqIo8e9sEIg rilYRcCYBllGchEL/fpQTplo3KEUwcB5PwnCVcavMtlAlPW5S8st6Tt7Yg5uKd4vVR7u JaT207PoQeQMrXthKCLmJLQ5+jwnKRzRBNkvHEdCnBNdB3eOKs69sTMbifC0LHR0ZT31 ovbEfxsIKWQ/foQoLrBRjRe/V3EIKBVTh1oiP9V/he4hp8MbhZ2lH+nCFJNfTVyvLqSe n43A== X-Gm-Message-State: AOAM5322fgTLbVdzUohVNpT++kHJXkhen2E3ey/vd6td5Rf5unszwPGK DlHUKYkBy+sMjmlDRoGaWkmOLyXr64r6Lw== X-Google-Smtp-Source: ABdhPJySl7aKw6SyAsUX0BlLcq+Iunh1Jd8aLAfhe1+DIbIzsH9SyptqXi5mP2K6s/38dcxuCvgjWg== X-Received: by 2002:a17:902:9303:b0:143:d6c7:babc with SMTP id bc3-20020a170902930300b00143d6c7babcmr63906116plb.58.1637596288038; Mon, 22 Nov 2021 07:51:28 -0800 (PST) Received: from realwakka ([59.12.165.26]) by smtp.gmail.com with ESMTPSA id k91sm8064429pja.19.2021.11.22.07.51.26 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 22 Nov 2021 07:51:27 -0800 (PST) Date: Mon, 22 Nov 2021 15:51:20 +0000 From: Sidong Yang To: Nikolay Borisov Cc: Graham Cobb , linux-btrfs , David Sterba Subject: Re: [PATCH v2] btrfs-progs: filesystem: du: skip file that permission denied Message-ID: <20211122155120.GA10576@realwakka> References: <20211121151556.8874-1-realwakka@gmail.com> <09d229c6-ae30-4453-c9d4-39109f032b99@suse.com> <20211122083240.GB8836@realwakka> <0a7ce0b1-300c-233b-d844-012dfc771efe@suse.com> <20211122151027.GA10523@realwakka> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org On Mon, Nov 22, 2021 at 05:20:30PM +0200, Nikolay Borisov wrote: > > > On 22.11.21 г. 17:10, Sidong Yang wrote: > > On Mon, Nov 22, 2021 at 12:57:18PM +0200, Nikolay Borisov wrote: > >> > >> > >> On 22.11.21 г. 11:53, Graham Cobb wrote: > >>> > >>> On 22/11/2021 09:32, Nikolay Borisov wrote: > >>>> > >>>> > >>>> On 22.11.21 г. 10:32, Sidong Yang wrote: > >>>>> On Mon, Nov 22, 2021 at 09:20:00AM +0200, Nikolay Borisov wrote: > >>>>>> > >>>>>> > >>>>>> On 21.11.21 г. 17:15, Sidong Yang wrote: > >>>>>>> This patch handles issue #421. Filesystem du command fails and exit > >>>>>>> when it access file that has permission denied. But it can continue the > >>>>>>> command except the files. This patch recovers ret value when permission > >>>>>>> denied. > >>>>>>> > >>>>>>> Signed-off-by: Sidong Yang > >>>>>> > >>>>>> > >>>>>> The code itself is fine so : > >>>>>> > >>>>>> > >>>>>> Reviewed-by: Nikolay Borisov > >>>>>> > >>>>>> > >>>>>> OTOH when I looked at the code rather than just the patch I can't help > >>>>>> but wonder shouldn't we actually structure this the way you initially > >>>>>> proposed but also add a debug output along the lines of "skipping > >>>>>> file/dir XXXX due to permission denied", otherwise users might not be > >>>>>> able to account for some space and they can possibly wonder that > >>>>>> something is wrong with btrfs fi du command. > >>>>> > >>>>> You mean that it would be better that print some debug message than > >>>>> skipping silently. I agree. So I would add this code in condition. > >>>>> > >>>>> fprintf(stderr, "skipping file/dir: %s : %m\n", entry->d_name); > >>>>> > >>>>> I think it's okay that it prints when ENOTTY occurs. Is this code what > >>>>> you meant? > >>>> > >>>> > >>>> I meant to print only if we have EACCESS, but now that I think about it, > >>>> printing something when we have a non-fatal error and simply skipping > >>>> some dirs/files makes sense. OTOH printing it by default might be too > >>>> verbose so perhaps usuing a pr_verbose call would be more appropriate. > >>>> > >>>> This is one of those things which don't have a clear-cut answers so it's > >>>> useful to get as many perspective as possible to arrive at some workable > >>>> solution to a wider number of people. > >>> > >>> I must admit I just assumed it worked the same way as /bin/du. I have > >>> just created an inaccessible directory and got: > >>> > >>> $ du -sh ~ > >>> du: cannot read directory '/home/cobb/permtest': Permission denied > >>> 61G /home/cobb > >>> > >>> And when the directory was accessible but the file in it was not, I got: > >>> > >>> $ du -sh ~ > >>> du: cannot access '/home/cobb/permtest/file': Permission denied > >>> 61G /home/cobb > >>> > >>> In other words, I think any error should be printed but the error is > >>> then skipped and the du continues. No need to tell people the file is > >>> being skipped - that is obvious. But the error must be printed by > >>> default (if there are really cases where the error should not be printed > >>> but reasons not to redirect stderr to /dev/null then add an option to > >>> suppress printing it). > >>> > >>> Just my opinion. > >> > >> > >> That actually works for me, I'd rather btrfs be as consistent as > >> possible and not give surprises to users. So just mimicking what an > >> omnipresent tool does is as good as it gets :) > > > > Yeah, I understood that any error should be printed but no need to print > > that it is skipped. I agree. If so, I think the code that print error > > message should like below. > > > > fprintf(stderr, "failed to walk dir/file: %s: %m\n", entry->d_name); > > > > I agreed that btrfs command should be like "du" command that familiar > > with users. I wonder if I understood it well. > > > > If so, I think it would be better that use switch-case than if-else. > > let's be inline with du: > > fprintf(stderr, "cannot access: '%s:' %m\n", entry->d_name); > > Also %m works with the error in errno and in this case the error is in > ret, so you'd need to set errno to ret. Thanks for a tip. I'll write next version of this patch. > > >> > >> > >>> > >>> Graham > >>> > >